Chapter 7. Hernias

A hernia is defined as an area of weakness or complete disruption of the fibromuscular tissues of the body wall. Structures arising from the cavity contained by the body wall can pass through, or herniate, through such a defect. While the definition is straightforward, the terminology is often misrepresented. It should be clear that hernia refers to the actual anatomic weakness or defect, and hernia contents describe those structures that pass through the defect.

Hernias are among the oldest known afflictions of humankind, and surgical repair of the inguinal hernia is the most common general surgery procedure performed today.1 Despite the high incidence, the technical aspects of hernia repair continue to evolve.

History

The word “hernia” is derived from a Latin term meaning “a rupture.” The earliest reports of abdominal wall hernias date back to 1500 bc. During this early era, abdominal wall hernias were treated with trusses or bandage dressings. The first evidence of operative repair of a groin hernia dates back to the first century ad. The original hernia repairs involved wide operative exposures through scrotal incisions requiring orchiectomy on the involved side. Centuries later, around 700 ad, principles of operative hernia repair evolved to emphasize mass ligation and en bloc excision of the hernia sac, cord, and testis distal to the external ring. The first report of groin hernia classification based on the anatomy of the defect (ie, inguinal versus femoral) dates back to the 14th century, and the anatomical descriptions of direct and indirect types of inguinal hernia were first reported in 1559.

Bassini revolutionized the surgical repair of the groin hernia with his novel anatomical dissection and low recurrence rates. He first performed his operation in 1884, and published his initial outcomes in 1889.2 Bassini reported 100% follow-up of patients over a 5-year period, with just five recurrences in over 250 patients. This rate of recurrence was unheard of at the time and marked a distinct turning point in the evolution of herniorraphy. Bassini's repair emphasizes both the high ligation of the hernia sac in the internal ring, as well as suture reinforcement of the posterior inguinal canal. The operation utilizes a deep and superficial closure of the inguinal canal. In the deep portion of the repair, the canal is repaired by interrupted sutures affixing the transversalis fascia medially to the inguinal ligament laterally. This requires an incision through the transversalis fascia. The superficial closure is provided by the external oblique fascia.

In addition to Bassini's contributions, the first true Cooper's ligament repair, which affixes the pectineal ligament to Poupart's ligament and thereby repairs both inguinal and femoral hernia defects, was introduced by Lotheissen in 1898. McVay further popularized the Cooper's ligament repair with the addition of a relaxing incision to reduce the increased wound tension.

The advances in groin hernia repair in the century following Bassini have shared the primary goal of reducing long-term hernia recurrence rates. To this end, efforts have been directed at developing a repair that imparts the least tension on the tissues that are brought together to repair the hernia defect. Darn repairs were first introduced in the early 20th century to reduce wound tension by using either autologous tissue or synthetic suture to bridge the gap between fascial tissues. Muscle and fascial flaps were attempted without consistent success. In 1918, Handley introduced the first use of silk as a prosthetic darn and nylon followed several years later. However, it was found that heavy prosthetic material increased the risk of wound infection, and the silk suture ultimately lost its strength over time. The use of autologous or synthetic patches was also attempted in order to reduce wound tension and improve rates of recurrence. The first patches, beginning in the early 20th century, consisted of silver wire filigree sheets that were placed along the inguinal canal. Over time, the sheets suffered from metal fatigue leading to hernia recurrence. Reports of the wire patches eroding into adjacent inguinal structures and even the peritoneal cavity itself caused even more concern with this technique. The modern synthetic patch, made of a plastic monofilament polymer (polyethylene), was introduced by Usher in 1958. Lichtenstein, who developed a sutureless hernia repair using a plastic mesh patch placed across the inguinal floor, further popularized this technique.

In the search for a technical means to reduce recurrence, emphasis was also placed on a meticulous dissection that would avoid placement of a prosthetic mesh. The most popular version was the Shouldice technique, initially introduced in 1958, and in essence a modification of the Bassini operation. This technique involves meticulous dissection of the entire inguinal floor and closure of the inguinal canal in four layers. The transversalis fascial layer itself is closed in two layers, as opposed to the single layer of interrupted suture advocated by Bassini. While the operation can be technically challenging to the beginner, it has been associated with excellent long-term outcomes and low recurrence rates.

Today, laparoscopic techniques have been validated as safe and effective in the treatment of groin hernias and have become commonplace. The laparoscopic approaches were initially developed in the early 1990s as laparoscopic techniques diffused throughout other specialties of general surgery.

Epidemiology

Seventy-five percent of all abdominal wall hernias are found in the groin, making it the most common location for an abdominal wall hernia. Of all groin hernias, 95% are hernias of the inguinal canal with the remainder being femoral hernia defects. Inguinal hernias are nine times more common in men than in women. Although femoral hernias are found more often in women, the inguinal hernia is still the most common hernia in women.3 The overall lifetime risk of developing a groin hernia is approximately 15% in males and less than 5% in females. There is clearly an association between age and hernia diagnosis. After an initial peak in the infant, groin hernias become more prevalent with advancing age. In the same way, the complications of hernias (incarceration, strangulation, and bowel obstruction) are found more commonly at the extremes of age.

Currently in this country, approximately 700,000 operations for inguinal hernia repair are performed annually.4

Anatomic Classification

A thorough classification system has been developed to assist in the proper diagnosis and management of the inguinal hernia. All hernias can be broadly classified as congenital or acquired, and it is thought that the vast majority of inguinal hernias are congenital in nature. Acquired groin hernias develop after surgical incision and manipulation of the involved abdominal wall tissues. Given the paucity of primary groin incisions utilized in modern general surgery, acquired hernias of the inguinal or femoral region are rare.

Inguinal hernias are further divided by anatomical location into direct and indirect types. This differentiation is based on the location of the actual hernia defect in relation to the inferior epigastric vessels. The inferior epigastric vessels are continuous with the superior epigastric vessels that originate from the internal mammary artery cephalad and ultimately course caudally into the common femoral artery and vein. These vascular structures make up the lateral axis of Hesselbach's triangle, which includes the lateral border of the rectus sheath as its medial border and the inguinal (Poupart's) ligament itself as the inferior border. Hernias that develop lateral to the inferior epigastric vessels are termed indirect inguinal hernias, and those that develop medial to the vessels are direct inguinal hernias. In this way, direct hernia defects are found within Hesselbach's triangle. Hernias of the femoral type are located caudal or inferior to the inguinal ligament in a medial position.

The indirect inguinal hernia develops at the site of the internal ring, or the location where the spermatic cord in men and the round ligament in women enters the abdomen. While they may present at any age, indirect inguinal hernias are thought to be congenital in etiology. The accepted hypothesis is that these hernias arise from the incomplete or defective obliteration of the processus vaginalis during the fetal period. The processus is the peritoneal layer that covers the testicle or ovary as it passes through the inguinal canal and into the scrotum in men or the broad ligament in women. The internal ring closes, and the processus vaginalis becomes obliterated following the migration of the testicle into the inguinal canal. The failure of this closure provides an environment for the indirect inguinal hernia to develop. In this way, the remnant layer of peritoneum forms a sac at the internal ring through which intra-abdominal contents may herniate, thereby resulting in a clinically detectable inguinal hernia. Anatomically, the internal ring is lateral to the external ring and the remainder of the inguinal canal, and this explains the lateral relationship of the indirect inguinal hernia to the inferior epigastric vessels. It is noteworthy that indirect inguinal hernia develops more frequently on the right, where descent of the gonads occurs later during fetal development.

Direct inguinal hernias, in contrast, are found medial to the inferior epigastric artery and vein, and within Hesselbach's triangle. These hernias are acquired and only rarely found in the youngest age groups. They are thought to develop from an acquired weakness in the fibromuscular structures of the inguinal floor, so that the abdominal wall in this region can no longer adequately contain the intra-abdominal contents. The exact relationship between direct inguinal hernias and heavy lifting or straining remains unclear, and some studies suggest that the incidence of direct hernia is no greater in people in professions that routinely involve heavy manual labor.5

While femoral hernias account for less than 10% of all groin hernias, their presentation can be more acute in nature. In fact, it is estimated that up to 40% of femoral hernias present as emergencies with hernia incarceration or strangulation.3 In this way, femoral hernias may also present with bowel obstruction. The empty space through which a femoral hernia forms is medial to the femoral vessels and nerve in the femoral canal and adjacent to the major femoral lymphatics. The inguinal ligament forms the cephalad border of the empty space. However, while the empty space is inferior to the ligament, the herniated contents may present superior to the ligament, thereby making an accurate diagnosis difficult.

Femoral hernias are much more common in females than in males, although inguinal hernias are still the most common hernia in women. The predilection for femoral hernias in women may be secondary to less bulky groin musculature or weakness in the pelvic floor tissues from previous childbirth. It has been shown that previous inguinal hernia repair may be a risk factor for the subsequent development of a femoral hernia.3

Anatomy of the Groin

The boundaries of the inguinal canal must be understood to comprehend the principles of hernia repair. In the inguinal canal, the anterior boundary is the external oblique aponeurosis; the posterior boundary is composed of the transversalis fascia with some contribution from the aponeurosis of the transversus abdominis muscle; the inferior border is imparted by the inguinal and lacunar ligaments; and the superior boundary is formed by the arching fibers of the internal oblique musculature.

The internal (or deep) inguinal ring is formed by a normal defect in the transversalis fascia through which the spermatic cord in men and the round ligament in women pass into the abdomen from the extraperitoneal plane. The external (or superficial) ring is inferior and medial to the internal ring and represents an opening of the aponeurosis of the external oblique. The spermatic cord passes from the peritoneum through the internal ring and then caudally into the external ring before entering the scrotum in males.

From superficial to deep, the surgeon first encounters Scarpa's fascia after incising the skin and subcutaneous tissue. Deep to Scarpa's layer is the external oblique aponeurosis, which must be incised and spread to identify the cord structures. The inguinal ligament represents the inferior extension of the external oblique aponeurosis, and extends from the anterior superior iliac spine to the pubic tubercle. The medial extension of the external oblique aponeurosis forms the anterior rectus sheath. The iliohypogastric and ilioinguinal nerves, which provide sensation to the skin, penis, and the upper medial thigh, lie deep to the external oblique aponeurosis in the groin region. The internal oblique aponeurosis is more prominent cephalad in the inguinal canal, and its fibers form the superior border of the canal itself. The cremaster muscle, which envelops the cord structures, originates from the internal oblique musculature. The transversus abdominis muscle and its fascia represent the true floor of the inguinal canal. Deep to the floor is the preperitoneal space, which houses the inferior epigastric artery and vein, the genitofemoral and lateral femoral cutaneous nerves, and the vas deferens, which traverses this space to join the remaining cord structures at the internal inguinal ring.

Etiology

The indirect inguinal hernia, the most common form of groin hernia across all ages and both genders, is thought to be congenital in etiology. The processus vaginalis is the pocket of peritoneum that forms around the testicle as it descends through the internal ring and along the inguinal canal into the scrotum during the 28th week of gestation. The primary etiology behind the indirect inguinal hernia is believed to be a patent processus vaginalis, which in essence represents a hernia sac. In this way, the hernia defect is the internal ring itself, and the sac is preformed but never closes at the end of gestation. Once intra-abdominal contents find their way into the sac, an indirect inguinal hernia is formed.

It is likely, however, that every person with a patent processus vaginalis does not develop an inguinal hernia during his or her lifetime. Thus, other predisposing factors must aid in indirect inguinal hernia formation. It is commonly thought that repeated increases in intra-abdominal pressure contribute to hernia formation; hence, inguinal hernias are commonly associated with pregnancy, chronic obstructive pulmonary disease, abdominal ascites, patients who undergo peritoneal dialysis, laborers who repeatedly flex the abdominal wall musculature, and individuals who strain from constipation. It is also thought that collagen formation and structure deteriorates with age, and thus hernia formation is more common in the older individual.

Several inborn errors of metabolism can lead to hernia formation. Specifically, conditions such as Ehlers–Danlos syndrome, Marfan's syndrome, Hunter's syndrome, and Hurler's syndrome can predispose to defects in collagen formation. There is evidence that cigarette smoking is associated with connective tissue disruption, and hernia formation is more common in the chronic smoker.

Clinical Manifestations

The groin hernia can present in a variety of ways, from the asymptomatic hernia to frank peritonitis in a strangulated hernia. Many hernias are found on routine physical examination or on a focused examination for an unrelated complaint. These groin hernias are usually fully reducible and chronic in nature. Such hernias are still referred for repair since they invariably develop symptoms, and asymptomatic hernias still have an inherent risk of incarceration and strangulation.

The most common presenting symptomatology for a groin hernia is a dull feeling of discomfort or heaviness in the groin region that is exacerbated by straining the abdominal musculature, lifting heavy objects, or defecating. These maneuvers worsen the feeling of discomfort by increasing the intra-abdominal pressure and forcing the hernia contents through the hernia defect. Pain develops as a tight ring of fascia outlining the hernia defect compresses intra-abdominal structures with a visceral neuronal supply. With a reducible hernia, the feeling of discomfort resolves as the pressure is released when the patient stops straining the abdominal muscles. The pain is often worse at the end of the day, and patients in physically active professions may experience the pain more often than those who lead a sedentary lifestyle.

Overwhelming or focal pain from a groin hernia is unusual and should raise the suspicion of hernia incarceration or strangulation. An incarcerated hernia occurs when the hernia contents are trapped in the hernia defect so that the contents cannot be reduced back into the abdominal cavity. The tight circumferential pressure applied by the hernia defect serves to impede the venous outflow from the hernia contents, resulting in congestion, edema, and tissue ischemia. Ultimately, the arterial inflow to the hernia contents is compromised as well, resulting in tissue loss and necrosis, termed strangulation of the hernia.

All types of groin hernias are at risk for incarceration and strangulation, although the femoral hernia seems to be predisposed to this complication. Incarceration and strangulation of a groin hernia may present as a bowel obstruction when the tight hernia defect constricts the lumen of the viscus. Hence, all patients presenting with bowel obstruction require a thorough physical examination of the groin region for inguinal and femoral hernias. If there is no bowel in the hernia sac, an incarcerated groin hernia may alternatively present as a hard, painful mass that is tender to palpation.

The physical examination differs between an incarcerated hernia and a strangulated hernia. The incarcerated hernia may be mildly tender due to venous congestion from the tight defect. The strangulated hernia will be tender and warm and may have surrounding skin erythema secondary to the inflammatory reaction from the ischemic bowel. The patient with the strangulated hernia may have a fever, hypotension from early bacteremia, and a leukocytosis. The incarcerated hernia requires operation on an urgent basis within 6–12 hours of presentation. If the operation is delayed for any reason, serial physical examinations are mandated to follow any change in the hernia site indicating the onset of tissue loss. The strangulated hernia clearly requires emergent operation immediately following diagnosis.

It may also be difficult to differentiate fat from bowel contents in the hernia sac. It is important to recognize that incarcerated omental fat alone can produce significant pain and tenderness on physical examination.

Pregnancy and Groin Hernia

Not surprisingly, groin hernias during pregnancy may become symptomatic. This is related to the increased intra-abdominal pressure from the growing fetus and enlarging uterus. The symptomatic groin discomfort may become positional later in pregnancy as the uterus shifts location with movement. While the risk of complications of groin hernias still exists during pregnancy, the enlarging uterus may in theory protect against incarceration by physically blocking the intra-abdominal contents from the inlet of the defect.

In general, elective repair of groin hernias during pregnancy is not recommended, even if they become increasingly symptomatic. Emergent repair of the incarcerated or strangulated hernia is undertaken as needed.

Physical Examination

As with any hernia, the groin hernia should be properly examined with the patient in the standing position. This allows the hernia contents to fill the hernia sac and make the hernia obvious on physical examination. Some hernias, however, may be easily identifiable in the supine position. It should be noted that the exact anatomical classification of the inguinal hernia (ie, indirect vs direct) is impossible to accurately predict based on physical examination alone.

In the male patient, using the second or third finger, the examiner should invaginate the scrotum near the external ring and direct the finger medial toward the pubic tubercle. The examiner's finger will thus lie on the spermatic cord with the tip of the finger within the external ring. The patient is then asked to cough or perform a Valsalva maneuver. A true inguinal hernia will be felt as a silklike sensation against the gloved finger of the examiner. This is the infamous “silk glove” sign.

The female patient does not have the long and stretched spermatic cord to follow with the examiner's finger during the physical examination. Instead, two fingers can be placed along the inguinal canal, and the patient is asked to cough or strain. If present, the examiner should feel the sensation of the hernia sac against the gloved finger. Particular attention in the female patient should be paid to the location of the sensation; femoral hernia sacs will present medial and just inferior to the lower border of the inguinal ligament.

While the physical examination does not differ in the infant, it can be more challenging to elicit the hernia impulse given the compressed groin anatomy of the young child. It is well known that a groin hernia can be more readily diagnosed in the infant who is actively crying and hence increasing the intra-abdominal pressure through flexion of the abdominal wall musculature.

The examination for the femoral hernia in both genders involves palpation of the femoral canal just below the inguinal ligament in the upper thigh. In this way, the most easily palpable landmark is the femoral artery, which is located lateral in the canal. Medial to the femoral artery is the femoral vein, and the femoral empty space is just medial to the vein. This area can be located easily, palpated with two fingers, and then examined closely while the patient coughs or strains. In general, a focused groin hernia examination should involve the investigation for both inguinal and femoral hernias in both genders.

Treatment

The treatment of all hernias, regardless of their location or type, is surgical repair. Elective repair is performed to alleviate symptoms and to prevent the significant complications of hernias, such as incarceration or strangulation. While the limited data available on the natural history of groin hernias show that these complications are rare, the complications are associated with a high rate of morbidity and mortality when they occur. At the same time, the risks of elective groin hernia repair, even in the patient with a complicated medical history, are exceedingly low. Outcomes of surgical repair are generally excellent with minimal morbidity and relatively rapid return to baseline health.

The major risk with delayed surgical repair is the risk of incarceration and/or strangulation. It is not possible to reliably identify those hernias that are at an increased risk for these complications. It is known that the risk of incarceration of a hernia is greatest soon after the hernia manifests itself. This is likely due to the fact that at the early stage of the hernia, the defect is small and fits tightly around the hernia sac; therefore, any contents that fill the sac may quickly become trapped within the hernia. Over time, the hernia defect stretches due to the tissue that enters and leaves the sac with changes in intra-abdominal pressure. After 6 months, the risk of hernia incarceration decreases from 5% per year to 1–2% per year. In general, the larger the palpable defect on physical examination, the lower the risk of incarceration. Clearly, all risks of tissue loss aside, elective hernia repair is still preferred to emergent repair.

Anesthesia

Groin hernia repair can be performed using a variety of anesthesia options, including general, regional (such as spinal or epidural), and local anesthesia.6 Laparoscopic repairs usually require general anesthesia in order to provide the complete muscle relaxation needed to achieve insufflation of the preperitoneal or peritoneal space.

Open groin hernia repairs are most often performed using either regional or local anesthesia. Local anesthesia with controlled intravenous sedation, referred to as monitored anesthesia care, is often preferred in the repair of the reducible inguinal hernia. Its advantages include the ease of induction and awakening, the short postanesthesia recovery period, and the fact that its intensity can easily be titrated up or down based on patient comfort levels intraoperatively. The only major disadvantage to this approach is in patients who experience considerable pain during repairs of large groin hernias.

In groin hernia repair, local anesthesia can be administered as a direct infiltration of the tissues to be incised or as a local nerve block of the ilioinguinal and iliohypogastric nerves. The latter is associated with improved local pain control, but may be difficult to achieve. The local nerve block also spares the soft tissue of edema from diffuse infiltration of local anesthesia.

Spinal or continuous epidural anesthesia allows the surgeon greater freedom to maneuver within the operative field since the anesthetized region is larger than in local anesthesia. However, these modes of anesthesia carry their own infrequent risks such as urinary retention, prolonged anesthetic effect, hypotension, and spinal headache. They may also be associated with longer in-hospital recovery times on the day of surgery.

A randomized trial of local, regional, and general anesthesia in 616 adult patients undergoing open inguinal hernia repair in 10 hospitals found that local anesthesia was superior in the early postoperative period.7 Compared to those who received regional or general anesthesia, patients who received local anesthesia had less postoperative pain and nausea, shorter time spent in the hospital, and fewer unplanned overnight admissions (3% vs 14% and 22%, respectively).

Operative Techniques

Successful surgical repair of a hernia depends on a tension-free closure of the hernia defect to attain the lowest possible recurrence rate. Previous efforts to simply identify the defect and suture it closed resulted in unacceptably high recurrence rates of up to 15%. Modern techniques have improved upon this recurrence rate by placement of mesh over the hernia defect, or in the case of laparoscopic repair, behind the hernia defect. One exception to this rule is the classic Shouldice repair, which uses meticulous dissection and closure without mesh placement to obtain a consistently low recurrence rate. Another benefit of the tension-free closure is that it has been shown to cause the patient significantly less pain and discomfort in the short-term postoperative period.

Figure 7-1 illustrates the essential steps to the modern open inguinal hernia repair. All of the open anterior herniorraphy techniques begin with a transversely oriented, slightly curvilinear skin incision of approximately 6–8 cm positioned one to two fingerbreadths above the inguinal ligament. Dissection is carried down through the subcutaneous and Scarpa's layers. The external oblique aponeurosis is identified and cleaned so that the external ring is identified inferomedially. Being careful to avoid injury to the iliohypogastric and ilioinguinal nerves, the aponeurosis is incised sharply and opened along its length through the external ring with fine scissors. The nerves underlying the external oblique fascia are then identified and isolated for protection. The soft tissue is cleared off the posterior surface of the external oblique aponeurosis on both sides and the spermatic cord is mobilized. Using a combination of blunt and sharp dissection, the cremaster muscle fibers enveloping the cord are separated from the cord structures and the cord itself is isolated. At this point, it is possible to accurately define the anatomy of the hernia. An indirect hernia will present with a sac attached to the cord in an anteromedial position extending superiorly through the internal ring. A direct inguinal hernia will present as a weakness in the floor of the canal posterior to the cord. A pantaloon defect will present as both a direct and an indirect defect in the same inguinal canal.

The specifics of the common modern techniques for hernia repair will be discussed further.

The Shouldice Technique

The Shouldice technique is commonly used for open repair of inguinal hernias and is the most popular pure tissue hernia repair. It is in essence the modern evolution of the Bassini repair performed in a multilayered fashion. Both operations use a tightening of the internal ring and closure of the transversalis fascia to the inguinal ligament as their primary tenets of hernia repair.8

Figure 7-2 illustrates the basic steps in the Shouldice repair. After suitable exposure and isolation of the cord, a pair of scissors is passed posterior to the transversalis fascia beginning at the medial pillar of the internal ring and extending inferomedially to the pubic tubercle. In this way, the transversalis fascia is separated from the preperitoneal fat plane. Care must be taken at this stage to preserve the inferior epigastric vessels that reside in the preperitoneal space. The transversalis fascia is then opened with scissors along the entire inguinal floor from internal ring to pubic tubercle, and the posterior surface of the transversalis is cleaned of its preperitoneal attachments. As the first layer of the repair, the free edge of the lower transversalis flap is sutured in a continuous, imbricated fashion behind the upper flap to the posterior surface of the upper transversalis fascia and the lateral component of the posterior rectus sheath. This running suture layer is started medially at the pubic tubercle and carried up to and through the internal ring, thereby tightening the transversalis fascia around the cord at its entrance to the inguinal canal. The first layer is not tied but continued in a running fashion from lateral to medial as a second layer closing the upper transversalis flap to the base of the lower edge as well as the inguinal ligament. This second layer progresses medially to the pubic tubercle where it is tied to the original tail that started the first layer. The third layer of continuous suture starts at the tightened internal ring and brings together the conjoined tendon (the internal oblique and transversus abdominis aponeuroses) medially with the inguinal ligament laterally. This layer is run down to the pubic tubercle, and returns to the internal ring as the fourth layer including the anterior rectus sheath medially with the posterior aspect of the external oblique aponeurosis laterally. The cord can now be relaxed gently on the new inguinal floor, and the external oblique aponeurosis is closed in one to two additional continuous layers extending down to the external ring to reapproximate this structure. The original descriptions of the operation by Shouldice used continuous stainless steel wire suture for all four layers of repair, although surgeons commonly use permanent synthetic suture today.

The Shouldice Hospital reports excellent long-term outcomes from their operation with recurrence rates less than 1% in selected patients.9,10 These results have not been achieved with any other pure tissue technique. The operation is well tolerated by most patients using local anesthesia only. From the multiple, overlapping, continuous suture lines, Shouldice proponents argue that any tension brought about in this type of closure is dispersed throughout the entire inguinal canal. The dissection is complicated, however, and requires excellent surgical technique and anatomic awareness. Moreover, other surgeons utilizing the Shouldice method have not achieved recurrence rates this low. Thus, the low rate of recurrence associated with the Shouldice technique likely depends on the level of surgical expertise and the patient selection. In one report of 183 inguinal hernia repairs using the Shouldice technique under local anesthesia, the recurrence rates for beginners versus more experienced surgeons were 9.4% versus 2.5%, respectively.11

A recent meta-analysis conducted by the Cochrane Collaboration compared the Shouldice technique with other open techniques for inguinal hernia repair.12 The analysis incorporated results from 16 different randomized or quasi-randomized studies and compared 2566 hernias repaired via the Shouldice technique with 1121 hernias repaired with mesh and 1608 hernias repaired with other nonmesh techniques. The recurrence rate for the Shouldice repair was significantly higher than mesh repair (odds ratio 3.8), but significantly lower than nonmesh repair (Odds Ratio 0.62). There were no significant differences between the groups with respect to complications, length of stay, or chronic pain following herniorraphy.12 Thus, the Shouldice technique is associated with a higher recurrence rate than mesh repairs, but appears to be the repair of choice in situations where mesh cannot be implanted.

The Cooper Ligament Repair

The Cooper ligament repair is the only technique that definitively repairs both the inguinal and femoral hernia defects in the groin. The operation is often named after Chester McVay, who popularized the operation in the 1940s and introduced the concept of the relaxing incision to decrease the tension from the repair. The repair is also a primary tissue repair in that no mesh is utilized.

The Cooper ligament repair begins similar to the Shouldice procedure, and exposure and isolation of the cord is performed. The transversalis fascia is then opened and cleaned posteriorly. At this time, Cooper's ligament is identified and dissected free of its fibrous and fatty attachments. The defects are repaired by using interrupted suture to affix the upper border of the transversalis fascia to Cooper's ligament beginning medially at the pubic tubercle and continuing until the femoral sheath is reached. At this point, the femoral canal is closed by carefully suturing Cooper's ligament to the femoral sheath. The repair is continued with interrupted sutures between the transversalis fascia and the iliopubic tract laterally until the entrance point of the cord is reached. In this way, the closure creates a new, and tighter, internal inguinal ring around the cord.

The Cooper ligament repair requires a relaxing incision because this pure tissue repair is associated with significant tension in closing all three groin hernia defects. After the transversalis fascia has been mobilized, and prior to the closure of the fascia to Cooper's ligament, a 2–4 cm vertical incision is made at the lateral border of the anterior rectus sheath beginning at the pubic tubercle and extending superiorly. The relaxing incision can be left open since the rectus muscle should protect against any herniation; alternatively, some surgeons argue for placement of a mesh over the relaxing incision since hernia formation can occur at this site.

The Cooper ligament repair is an outstanding technique for a femoral hernia and is associated with excellent long-term results in experienced hands. Disadvantages of the repair include a longer operating time, a more extensive dissection, the potential for vascular injury and thromboembolic complications from the femoral vessels, and a longer postoperative recovery phase.

Prosthetic Repairs

Polypropylene mesh is the most common prosthetic used today in mesh repairs of the inguinal hernia. The two most common prosthetic repairs are the Lichtenstein13 and the “plug and patch” repair as described by Gilbert14 and popularized by Rutkow and Robbins.15

The type of mesh to be used during prosthetic inguinal hernia repairs deserves a brief discussion. The most common and preferred mesh for groin hernia repair is a polypropylene woven mesh marketed under a variety of names. Polypropylene is preferred because it allows for a fibrotic reaction to occur between the inguinal floor and the posterior surface of the mesh, thereby forming scar and strengthening the closure of the hernia defect. This fibrotic reaction is not seen to the same extent with other varieties of prosthetic, namely expanded polytetrafluoroethylene (PTFE) mesh. PTFE is often used for repair of ventral or incision hernias in which the fibrotic reaction with the underlying serosal surface of the bowel is best avoided.

There are limited prospective, randomized data comparing the recurrence rate of open prosthetic repairs versus open nonprosthetic repairs. An attempted meta-analysis concluded that mesh repair was associated with fewer overall recurrences, although the authors report that formal analysis was limited by the lack of available study data.16 A review of 26,000 inguinal hernia repairs from Denmark found that mesh repairs had a lower reoperation rate than conventional open repairs.17 The majority of groin hernia repairs performed in the United States in the modern era utilize mesh placement.

The Lichtenstein Technique

The Lichtenstein inguinal hernia repair was the first pure prosthetic, tension-free repair to achieve consistently low recurrence rates in long-term outcomes analysis. This operation begins with the incision of the external oblique aponeurosis, and the isolation of the cord structures. Any indirect hernia sac is mobilized off the cord to the level of the internal ring. At this point, a large mesh tailored to fit along the inguinal canal floor is placed so that the curved end lies directly on top of the pubic tubercle. The mesh patch extends underneath the cord until the spermatic cord and the tails of the mesh patch meet laterally. Here, an incision is made in the mesh, and the cord is inserted between the tails of the mesh, thereby creating a new, tighter, and more medial internal ring. The tails are sutured together with one nonabsorbable stitch just proximal to the attachment of the cord. The mesh is then sutured in a continuous or interrupted fashion to the pubic tubercle inferiorly, the conjoined tendon medially, and the inguinal ligament laterally.

Rutkow and Robbins have reported interesting and effective advances in the Lichtenstein technique. The “plug and patch” repair, as illustrated in Fig. 7-3, represents a tension-free herniorraphy and can even be performed without sutures. In this technique, the patch is placed in a similar fashion to the modern Lichtenstein repair as it lies along the inguinal canal from the pubic tubercle medially to beyond the cord laterally. In addition, a mesh plug in the form of an umbrella or cone is snugly fit up and into the internal ring. In this way, the repair goes beyond just a tightening of the internal ring, but serves to close the ring around the spermatic cord. Modifications of this operation exist and are practiced commonly by general surgeons. The patch and plug can be sutured to the surrounding inguinal canal tissue in an interrupted or continuous fashion. Alternatively, both prostheses can be placed in appropriate position with no suture affixment. In this way, the body's natural scarring mechanism will hold both pieces of mesh in place over time. Wide internal ring defects, often caused by large or chronic indirect sacs, may require one or two sutures to tack the plug in place to avoid slippage into the canal anteriorly or the retroperitoneal space posteriorly.

The Preperitoneal Approach

The preperitoneal space is found between the transversalis fascia and the peritoneum itself. The actual groin hernia defect is located anterior to this space, whether the defect exists in the internal ring (indirect inguinal hernia) or through the transversalis floor of the inguinal canal (direct inguinal hernia). Several authors, including Rives, Nyhus, Stoppa, and Kugel, advocate the use of a preperitoneal or posterior approach to repair the inguinal hernia. They argue that this approach is more effective than the traditional anterior herniorraphy because a repair in the preperitoneal plane fixes the hernia defect in the space between the hernia contents and the hernia defect. In contrast, the anterior approach does not keep the hernia contents from contact with the defect, but rather fixes the hernia defect anterior to the defective anatomy. The operation is also advocated for difficult inguinal hernia recurrences, since the posterior approach will usually remain open and without scar following a previous anterior hernia repair. The original operation as described by Nyhus repairs the hernia primarily with suture, although more recent modifications incorporate a mesh patch posterior to the floor of the inguinal canal. As described later in this chapter, the standard laparoscopic technique for inguinal hernia repair is based entirely on the preperitoneal hernia repair.

Figures 7-4 and 7-5 illustrate the preperitoneal repair as described by Rives.18 In the preperitoneal hernia repair, the incision is usually made transversely in the lower quadrant 2–3 cm cephalad to the inguinal ligament. The incision is made slightly more medial than the anterior approach so that the lateral border of the rectus muscle can be exposed after incising the anterior rectus sheath. Once the muscle is exposed, retraction of the rectus muscle medially allows for careful opening of the posterior rectus sheath and entry into the preperitoneal space. The inferior epigastric vessels and the cord can be visualized in this space. The cord usually does not require extensive manipulation or dissection since the usual cord attachments (lipoma and cremaster fibers) are found in the anterior layers of the inguinal canal. In this way, the approach also avoids exposure to the sensory nerves of the inguinal canal.

Once the preperitoneal space has been entered and exposed, the specific repair to be performed depends on hernia anatomy. For direct defects, the sac is inverted back into the peritoneal cavity but does not need to be excised. The transversalis fascia is then reapproximated over the inverted sac using interrupted sutures; in this way, the upper border of the transversalis fascia is affixed to the lower border composed of the iliopubic tract. For indirect defects, the sac is reduced off of the cord and a high ligation of the sac is performed at the sac neck; ironically, with this approach, the “high ligation” is actually a “posterior” ligation, since the surgeon ideally should transect the sac just above the preperitoneal fat, which is situated along the inferior border of the exposed field. Once the sac has been ligated, the defect in the internal ring is repaired from the posterior plane using interrupted suture to affix the ring leaflets of the transversalis fascia to the iliopubic tract, thereby tightening the ring itself.

Modifications of this approach using the prosthetic mesh patch are relatively straightforward. The mesh patch is placed underneath the transversalis fascia and directly on the preperitoneal fat. This patch, if placed completely over the inguinal region, covers any peritoneum that could potentially form a hernia sac through a direct or indirect fascial defect.

Laparoscopic Repair

Laparoscopic groin hernia repair was first performed by Ger in 1979, although it was only within the past decade and a half that laparoscopic hernia repair became more accepted. The laparoscopic approach to hernia repair has since evolved into a common and effective procedure. Today, the laparoscopic approach comprises approximately 20–25% of groin hernia operations and 80,000–100,000 laparoscopic hernia repairs are performed annually in the United States. The most important difference between the laparoscopic and open approaches for inguinal hernia repair is anatomical: the laparoscopic approach uses mesh to repair the hernia defect in a plane posterior to the defect (either in the preperitoneal space or from within the peritoneal cavity), whereas the open approaches repair the hernia anterior to the defect.

Three different techniques exist for laparoscopic repair of groin hernias. The transabdominal preperitoneal (TAP) repair involves standard laparoscopy with access into the peritoneal cavity and placement of a large mesh along the anterior abdominal wall, thereby repairing the hernia posterior to the defect. This technique was the first laparoscopic hernia repair to be performed. Ports are generally placed through the umbilicus and then laterally on either side of the rectus muscle. The hernia defect is usually well visualized from within the peritoneal cavity. After both inguinal regions have been inspected and laparoscopic adhesiolysis performed if necessary, the median umbilical ligament (the urachal remnant), the medial umbilical ligament (the remnant of the umbilical artery), and the lateral umbilical fold (the reflection of peritoneum over the inferior epigastric vessels) are identified. The parietal layer of peritoneum is then incised superior to the hernia defect and reflected inferiorly, thereby exposing the hernia defect, the epigastric vessels, Cooper's ligament, the pubic tubercle, and the iliopubic tract. The cord structures are then dissected free of their peritoneal attachments. In a direct hernia, the peritoneal sac is pulled back within the peritoneal cavity with gentle traction to separate the thin peritoneal layer from the equally thin layer of transversalis fascia anterior to it. In an indirect hernia, the peritoneal sac is retracted off of the cord structures and pulled back within the peritoneal cavity. Alternatively, in the setting of a large chronic indirect hernia, the sac can be divided distal to the internal ring so that only the proximal portion of the sac needs to be mobilized for the repair. A large polypropylene mesh patch is then placed between the peritoneum and the transversalis fascia that covers the inguinal floor, internal ring, and the femoral canal. The mesh is stapled or tacked to the pubic tubercle medially, Cooper's ligament inferiorly, and the anterior superior iliac spine laterally. The incised peritoneal flap is then closed over the mesh.

While the TAP repair has been shown to be effective, there is a risk that the prosthetic mesh will be in direct content with the bowel, and significant concern has been raised about the potential for intra-abdominal adhesions postoperatively.19 Enthusiasm for this technique has waned in recent years with the advent of extraperitoneal laparoscopic approaches to inguinal hernia repair.

The total extraperitoneal (TEP) approach to laparoscopic inguinal hernia repair is currently the most popular laparoscopic technique. This repair is performed entirely within the preperitoneal space and does not involve the peritoneal cavity when performed correctly. In this technique, the surgeon carefully develops a plane between the peritoneum posteriorly and the abdominal wall tissues anteriorly, and thus insufflates the preperitoneal space. An incision is made inferior to the umbilicus, and the anterior rectus sheath on the ipsilateral side is incised. The rectus muscle is retracted laterally, and the preperitoneal space is bluntly dissected to allow placement of a balloon port to facilitate insufflation. Once the space has been insufflated, two additional ports are placed in the midline between the umbilicus and the pubic symphysis. In experienced hands, this approach provides for excellent visualization of the groin anatomy, and the dissection proceeds in a similar fashion to the TAP. The TEP repair allows a large prosthetic mesh to be placed through a laparoscopic port into the preperitoneal space, and it is then positioned deep to the hernia defect to repair the hernia from a posterior approach.20

The intraperitoneal onlay mesh technique (IPOM) was developed as a simplified version of the TAP repair. In this technique, laparoscopic exposure is obtained directly into the peritoneal cavity as in the TAP. However, this technique does not require an extensive mobilization of the peritoneal flap and dissection of the preperitoneal space. Rather, a large mesh is simply stapled or sutured directly posterior to the peritoneum to repair the hernia. In theory, once the peritoneum scars to the mesh after allowing for connective tissue in-growth, the peritoneum will not be mobile enough to herniate through the actual defect and intra-abdominal pressure will keep the abdominal contents posterior to the mesh patch. The disadvantage of this procedure is that there is direct exposure of mesh to the intra-abdominal contents and therefore a high risk of adhesion formation and possible erosion of the mesh into bowel contents. Another potential disadvantage of the IPOM is the fact that in large inguinal hernias, the mesh and peritoneum may herniate through the defect together, thereby negating any protective effect imparted by the mesh patch. Therefore, at the present time, this procedure is thought to be experimental only.

There are few prospective, randomized data available to adequately judge short- and long-term results of the different laparoscopic inguinal hernia techniques. A systematic review by the Cochrane Collaboration in 2005 found that among the several nonrandomized trials, TAP was associated with an increased rate of port site herniation and visceral organ injury. This review concluded that there are insufficient data from prospective, randomized trials to make firm conclusions about the relative effectiveness of the TEP and TAP procedures.21

There are emerging data comparing laparoscopic techniques to open inguinal hernia repair, although the evidence is far from definitive. While there are multiple meta-analyses in the literature, only two truly compare the laparoscopic hernia technique with a tension-free open repair. A meta-analysis of 29 randomized trials in 2003 found that laparoscopic hernia repair was associated with earlier discharge from the hospital, quicker return to normal activity and work, and fewer postoperative complications than open repair.22 However, in these data there was a trend toward an increase in the risk of recurrence after laparoscopic repair. A separate meta-analysis reviewing 41 published randomized trials found no significant difference in risk of recurrence between the two approaches.23 Laparoscopic repair was associated with a quicker return to function and less postoperative pain, but also was found to have a higher risk of visceral and vascular injuries. A more recent multicenter, randomized trial that analyzed long-term hernia results in over 2000 patients in 14 Veterans Affairs hospitals found that laparoscopic hernia repair was associated with a higher recurrence rate among primary hernias, but was equivalent to open repair in recurrent hernias.24 In all of these studies, the laparoscopic repair was noted to take more time in the operating room. Proper laparoscopic technique also appears to play a significant role in recurrence rates. In a randomized, multicenter trial comparing 665 TEP versus 705 Lichtenstein repairs with 5-year follow-up, authors initially found that the recurrence rate following TEP (3.5%) was significantly higher (p = 0.008) than that following Lichtenstein (1.2%).25 However, when they removed a single surgeon who was responsible for 33% of all the recurrences in the TEP group, the cumulative recurrence rate for TEP was lowered to 2.4% and was not statistically different from the Lichtenstein group. Finally, a recent study has reported a significant learning curve inherent in the laparoscopic approach.26 Clearly, more definitive multicenter data from surgeons experienced in both procedures are needed to reach formal conclusions about the utility of both hernia approaches.

A separate issue that deserves further study in laparoscopic hernia repair is the anatomical disturbance of the space of Retzius. This area, first described by Retzius in the 19th century, is the prevesical space located anterior and lateral to the bladder. Suprapubic prostatectomy is performed with dissection through this space, and this operation may be made more difficult following laparoscopic hernia repair.

Although groin hernia repair is associated with excellent short- and long-term outcomes, complications of the procedure exist and must be recognized.

Recurrence

Recurrence of the hernia in the early postoperative setting is rare. When this does occur, it is often secondary to deep infection, undue tension on the repair, or tissue ischemia. Clearly, all of these etiologies raise the concern for a technical complication on the part of the surgeon, either in the handling of the groin tissues or the placement of mesh or suture. The patient who is overactive in the immediate postoperative setting may also be at risk for early hernia recurrence. In this way, it is thought that early exercise is performed before the suture or mesh in the repair has had an opportunity to hold tissue in place and promote scar tissue formation. In the initial postoperative setting, patients may also develop seromas along the planes of dissection as well as fluid in the obliterated hernia sac. These benign consequences of surgery must be differentiated from the more worrisome early recurrence.

Tension is an important, if not the primary, etiology of hernia recurrence. Tissues repaired under undue tension will tend to pull apart, even if sutures or mesh has been affixed to them. In addition, tension at the site of suture may lead to ischemia at the point where the suture pulls against the tissue, thereby further weakening the hernia repair. Sutures can also cut out or fall apart, especially if placed in a continuous fashion, when tensile force predominates. The role of excessive tissue tension in promotion of hernia recurrence is the basic rationale behind the modern, tension-free, and increasingly suture-free hernia repairs advocated by hernia experts such as Lichtenstein and Rutkow.

The size of the hernia defect is proportional to the risk of hernia recurrence. Larger hernias have an increased rate of recurrence postoperatively. This is most likely due to the nature of the surrounding fascial tissues that are critical to the strength and reliability of the repair. As large hernias stretch and attenuate the surrounding fascial planes, these tissues are correspondingly weaker when repaired with suture or mesh. The weakened tissue may also be relatively ischemic at the time of hernia repair, although this has not been adequately studied.

An emergency operation for strangulated or incarcerated hernia may increase the risk of postoperative recurrence. It is likely that the strangulated hernia, with its inherent inflammation, tissue ischemia, and fascial edema, provides an environment in which the hernia repair is placed either at increased tension or through unhealthy tissue.

A hernia that is overlooked in the operating room represents a potential etiology of hernia recurrence, although this should not be a major concern for the modern hernia surgeon. Most of the repairs in the current era emphasize the repair of both an indirect and a direct defect through strengthening of the internal ring and inguinal canal floor, respectively.

A final etiology of hernia recurrence pertains to tobacco use and smoking. The relationship between smoking and hernia formation as well as recurrence was first reported in 1981 and further research has identified proteolytic enzymes that may degrade the connective tissue components.27

Infection

Infection of the hernia wound or mesh is an uncommon postoperative complication but represents another etiology of hernia recurrence. In specialized hernia practices, the incidence of wound infection following inguinal hernia operation is 1% or less. When an infection does occur, skin flora is the most likely etiology, and appropriate gram-positive antibiotics should be initiated. Patients who undergo mesh placement during groin herniorraphy are at a slightly higher risk of postoperative wound infection. It is often difficult to determine whether the mesh itself is infected or if just the skin or soft tissue anterior to the layer of mesh is infected. However, even if mesh is present, most postoperative groin hernia infections can be treated with aggressive use of antibiotics after the incision is opened and drained expeditiously.28 Mesh removal in this setting is rarely indicated; when this is mandated, primary closure or redo herniorraphy with a synthetic tissue substitute may be warranted and a preperitoneal approach may be necessary.

Seromas and hematomas are frequent complications in the postoperative setting. Seromas form in the dead space remaining from a wide dissection during the hernia repair or when fluid fills the distal remnant of the hernia sac. While the sac is often ligated or excised during open herniorraphy, it remains in place following laparoscopic repair, and the filling of the remnant sac with seroma-type fluid has been termed a pseudohernia. This must be differentiated from the more concerning complication of the early recurrent hernia. Defined fluid collections infrequently require drainage or aspiration, as most will reabsorb or drain through the incision on their own.

Hematoma formation must be assiduously avoided during groin hernia repair. This is especially true in the anticoagulated patient, and therefore it is recommended that patients temporarily stop taking aspirin and clopidogrel at least 1 week prior to their operation. Hematoma formation may be minor and lead only to ecchymoses and wound drainage. The ecchymosis often spreads inferiorly into the scrotal plane in a dependent fashion. The hematoma usually resolves in days to weeks following repair and supportive management for pain control including scrotal elevation and warm packs is all that is required. A large volume of hematoma is concerning, as it may serve as a nidus for infection deep in the hernia wound and may risk secondary infection of the prosthetic mesh. Therefore, hemostasis at the end of a groin hernia repair is paramount to achieve effective wound healing.

Neuralgia

Postoperative groin pain, or neuralgia, is common to varying degrees following groin herniorrhaphy.29 Often, the neuralgia will follow the known distribution of the regional nerves, including the ilioinguinal, iliohypogastric, genital branch of the genitofemoral nerve, and the lateral femorocutaneous nerves. During open hernia repair, the ilioinguinal, iliohypogastric, and the genitofemoral nerves are most commonly injured, while the lateral femorocutaneous nerve is more commonly injured during laparoscopic herniorraphy. Nerve injury is usually due to entrapment of a portion of the nerve in the mesh or suture line placed in one of the soft tissue layers.

Neuralgias can be prevented by meticulously avoiding overt manipulation of the nerves during operative dissection. The ilioinguinal and iliohypogastric nerves are generally injured during elevation of the external oblique fascial flaps, while the genitofemoral nerve is most likely to be injured during the isolation of the cord and stripping of the cremaster muscle fibers. Often, once the nerve branches are identified, they are encircled with a vessel loop and retracted out of the operative field to avoid injury. The nerves can also be intentionally sacrificed at time of surgery. The result of this maneuver is a region of sensory deprivation in the distributions of these nerve structures, namely on the inner upper thigh and the hemiscrotum. However, the sensory deprivation is thought to be better tolerated by the patient than the chronic and persistent pain attributed to nerve entrapment in scar or mesh. In laparoscopic repair, nerve injury can be prevented by avoiding tack or staple placement below the iliopubic tract.

Neuralgia should first be managed conservatively, with attempts at local anesthetic injection in the affected groin. When local anesthesia is injected along the known course of a nerve, this modality may serve as both a diagnostic and a therapeutic maneuver. In some cases, temporary control of the chronic pain with local anesthesia may reduce or altogether eliminate the sequelae of chronic groin pain. When this conservative approach does not succeed, groin re-exploration can be performed to ligate or excise affected nerve branches. This is clearly not the preferred first option, since the groin wound has abundant scar and previously undamaged nerve structures may be placed at additional risk. Occasionally, patients will present with postoperative neuralgia that does not match the distribution of any known inguinal nerve. Groin re-exploration should be avoided in this case since it is unlikely to ameliorate the pain and may damage additional structures.

Nerve injury during laparoscopic repair can occur during the tacking of the mesh to the anterior abdominal wall. Tacks should be avoided in the known areas of nerve structures. Some surgeons prefer to not place any tacking staples at all when performing laparoscopic herniorraphy to avoid this complication altogether.

Bladder Injury

The urinary bladder may be inadvertently injured during dissection of a direct inguinal hernia sac, but only rarely during repair of an indirect defect. The bladder can also participate in a sliding hernia so that a portion of the bladder wall is adherent to the sac in a direct defect. Because of the potential for this complication, direct sacs should be inverted into the peritoneal cavity so that excessive dissection can be avoided. If bladder injury takes place, the sac should be opened, and the bladder injury repaired in two layers of an absorbable suture. In general, a urethral catheter is placed for a minimum of 7–14 days.

Testicular Injury

Testicular swelling and atrophy is seen after inguinal hernia repair. Edema of the scrotum or testis may be secondary to edema or hematoma of the inguinal canal that tracks inferomedially to the scrotum in a dependent fashion. Alternatively, a tender testicle or an atrophic testicle may be secondary to injury to the blood supply to the genitals during dissection and isolation of the cord. In most cases, this is not an emergency in the adult patient, and the testes will atrophy without significant infectious complications so that orchiectomy is rarely necessary. A testicle that is tender on examination may require ultrasonographic imaging to rule out testicular torsion or a corresponding abscess. Necrosis of the testes, a very rare complication of groin hernia repair, usually requires orchiectomy to avoid infectious complications.

In the pediatric patient, traction on the cord in the cephalad direction can cause the testes to migrate into the inguinal canal and out of the scrotum. For this reason, the scrotum is often prepped sterilely in the pediatric inguinal hernia operation, and the testes are confirmed to be in appropriate position by palpation at the end of the hernia repair. If the testes remain in the inguinal canal following herniorraphy, this may require manipulation of the testes further down the canal and into the scrotum using a long atraumatic forceps or a choker instrument.

Vas Deferens Injury

Injury to the vas deferens is a rare complication of groin hernia surgery in the male patient. Transection of the vas is the most serious form of this injury; this requires urologic consultation and likely immediate reanastomosis in the child or young adult, but may only require ligation of both ends in the older adult patient. Minor injuries to the vas can be avoided by using gentle, atraumatic traction only and by avoiding complete grasping or squeezing of the vas. The most worrisome sequela of vas deferens obstruction or transection is formation of antisperm antibodies in the serum, leading to infertility.

The strangulation of a groin hernia is a complication of the hernia itself rather than of a hernia repair. This pathophysiologic process is associated with a high rate of mortality and morbidity, especially in the elderly population with multiple comorbidities. The risk of strangulation is highest in the first months to years after the initial presentation of a reducible hernia. Gallegos and associates estimated the probability of inguinal hernia strangulation over time to be 2.8% over 3 months and 4.5% at 2 years.30 It is likely that with time, the hernia contents weaken the hernia defect and widen the hernia neck so that the sac is no longer compressed as tightly, thereby decreasing the opportunity for incarceration and strangulation to take place.

The mortality from a strangulated hernia is related to the duration of the strangulation and the age of the patient. A longer duration of strangulation leads to a greater degree of tissue edema, ischemia, and risk of outright necrosis. Therefore, a strangulated hernia clearly represents a surgical emergency. The incarcerated hernia without overt signs of strangulation on examination and laboratory analysis should undergo attempts at reduction, often requiring conscious sedation to minimize discomfort. After the hernia is reduced, the repair can take place 1–2 days later, usually during the same inpatient hospitalization, to minimize risk of recurrent incarceration leading to strangulation.

Surgery for an incarcerated inguinal hernia is most often performed under general anesthesia given the high likelihood that bowel resection will need to be performed. Epidural or spinal anesthesia may suffice in select cases, but local anesthesia should not be employed. The location of the incision depends on the diagnosis and clinical assessment. In those patients who are unlikely to have ischemic bowel present within the hernia sac, an inguinal incision will likely be successful in both reducing the hernia contents and repairing the hernia defect. If nonviable bowel is found on exploration of the inguinal canal, the resection and anastomosis can take place deep to the transversalis fascia in the preperitoneal space or a midline incision can be made. If the initial physical examination yields signs of ischemic bowel that may necessitate resection, a midline laparotomy can be performed and the hernia repaired in the inguinal canal using a tissue repair after the laparotomy is closed. A helpful alternative is the preperitoneal hernia repair, which can be used to evaluate the bowel and repair the hernia defect; yet it can also be easily converted to an intraperitoneal exposure if extensive bowel resection and anastomosis is required. Placement of prosthetic mesh should be avoided when possible in strangulated hernia repair given the increased risk of bacterial translocation and wound infection.

The femoral hernia is the second most common abdominal wall hernia, although it makes up only 5–10% of all hernias. The femoral hernia is more common in females than in males, by a ratio of approximately 4:1.

Anatomy and Etiology

Figure 7-6 illustrates the anatomy of the femoral hernia. The defect through which a femoral hernia occurs is in the medial femoral canal. The anterior boundary of this defect is the inguinal ligament, the lateral boundary the femoral vein, the posterior boundary the pubic ramus and Cooper's ligament, and the medial boundary the lacunar portion of the inguinal ligament. This space is obviously tight and does not have room to expand when hernia contents fill the sac since the boundaries are either ligamentous, bony, or the fibrous femoral sheath and its vessels. Therefore, femoral hernias have a high propensity for incarceration and strangulation. Gallegos and associates reported the cumulative probability of femoral hernia strangulation to be 22% in the first 3 months following diagnosis and 45% at nearly 2 years.30 Therefore, repair of a known femoral hernia is mandatory to avoid this highly morbid complication.

In contrast to the inguinal hernia, the femoral hernia is unlikely to be of congenital etiology. The incidence of femoral hernia in infancy and childhood is exceedingly low, in the range of 0.5%. In addition, there is no embryologic mechanism for a preexisting sac of peritoneum in the femoral canal. The hernia defect most often presents in middle-aged to older women, suggesting that the natural loss of tissue strength and elasticity is a primary etiology.

Clinical Presentation

The femoral hernia often presents as a small bulge just below the medial groin crease. It is often difficult to reduce on initial presentation.31 The hernia usually extends caudad as the sac increases in size with abdominal contents but may extend up and over the inguinal ligament anteriorly. Not uncommonly, the femoral hernia presents acutely with strangulation given its anatomic limitations. The differential diagnosis for a femoral hernia includes femoral lymphadenopathy, groin lipoma, or a soft tissue mass of benign or rarely malignant nature.

Treatment

The operative approach to repairing the reducible femoral hernia differs from inguinal hernia repair in several ways. The incision is usually centered transversely just below the inguinal ligament, although a standard groin hernia incision may still afford exposure to the defect. The simplest approach is anterior to the inguinal ligament. Here, the sac can often be found, dissected, and reduced into the peritoneal cavity. Repair of the defect can be performed using a Cooper ligament repair as described above, by affixing the transversalis fascia to the Cooper's ligament medially and the iliopubic tract laterally up to the internal ring. Alternatively, a simple suture repair can be performed by tacking the inguinal ligament anteriorly to Cooper's ligament posteromedially to close the defect. A third option is a purse-string suture placed first anteriorly into the inguinal ligament, then through the lacunar ligament medially, the pectineal ligament posteriorly, and finally through the fascia medial to the femoral vein and back to the inguinal ligament. All of these techniques can successfully close the femoral hernia defect.

However, a unique complication from suture repair of the femoral hernia defect is bleeding from an aberrant obturator artery. This vessel originates from the inferior epigastric rather than the internal iliac artery and traverses a space medial to the femoral hernia defect adjacent to the pubic ramus. The medial suture placed in femoral hernia repair can injure an aberrant obturator artery if present. A simple and possibly safer way to repair the femoral defect is a mesh plug placed from cephalad to caudad to obstruct the defect and promote scar tissue formation. This technique, shown in Fig. 7-7, has been reported by Lichtenstein with excellent results and low rates of recurrence.32

If the femoral hernia sac is large and filled with voluminous intra-abdominal contents, a preperitoneal repair should be considered. In this way, the transversalis fascia is opened and the preperitoneal plane is entered. This approach is particularly useful during repair of a strangulated hernia since there is more space to allow for inspection of the bowel to ensure viability. Bowel resection, if needed, can also take place in the preperitoneal space prior to full reduction of the hernia contents.

The umbilicus represents a midline opening in the linea alba. Umbilical hernia occurs when the umbilical scar closes incompletely in the child or fails and stretches in later years in the adult patient. The hernia becomes readily apparent once the abdominal contents move through the umbilical opening given the relative lack of soft tissue in the anterior body wall at the site of the umbilicus.

History

Umbilical hernias have been documented throughout history with the first references dating back to the ancient Egyptians with the first known record of a surgical repair by Celsus in the first century ad. Mayo in 1901 reported the first series of patients to undergo the classic overlapping fascia operation through a transverse umbilical incision using nonabsorbable suture.33

Incidence

Estimates of umbilical hernia present at birth have a wide range. In Caucasian babies, the incidence has been reported at 10–30%, although for unknown reasons it may be several times greater in African-American children. Umbilical hernia is even more common in premature infants of all races and there is a tendency for familial inheritance.

The majority of congenital pediatric umbilical hernias are known to close over time, as the infant becomes a child. In this way, by school age, only 10% of umbilical hernias remain open on physical examination. Umbilical hernia repair in the child is therefore rarely performed electively before the age of 2 years, and incarceration in the child is rare. Current recommendations in the pediatric surgical literature advise the delay of umbilical hernia repair until at least 2–3 years of age given the likelihood that most umbilical hernias will spontaneously close in the young child.

The incidence of umbilical hernia in the adult is largely unknown but most cases are thought to be acquired rather than congenital. It is known to occur more commonly in adult females with a female:male ratio of 3:1. Umbilical hernia is also more commonly found in association with processes that increase intra-abdominal pressure, such as pregnancy, obesity, ascites, persistent or repetitive abdominal distention in bowel obstruction, or peritoneal dialysis. The etiology of umbilical hernia in the adult may be multifactorial, with increased intra-abdominal pressure working against a weak or incomplete umbilical scar.

Embryology and Anatomy

The fascial margins that make up the umbilical defect are formed by the third week of gestation, and the umbilical cord takes shape in the fifth week of gestation. In the sixth week, the intestinal tract migrates through the umbilicus and outside the coelom as intestinal growth outpaces the size of the abdominal cavity. The intestinal tract returns to the abdominal cavity through the umbilical defect as the midgut undergoes rotation at the tenth week of gestation, and subsequent to this, the four folds of the somatopleure begin to fuse inward. This, in turn, forms the tight umbilical defect, which allows only the passage of the umbilical vessels. At birth, when the umbilical cord is manually ligated, the umbilical arteries and vein thrombose and the umbilical aperture close. Any defect in the process of umbilical closure will result in an umbilical hernia through which omentum or bowel can herniate.

Clinical Manifestations

The diagnosis of umbilical hernia is not difficult to make. The condition presents with a soft bulge located anterior or adjacent to the umbilicus. In most cases, the bulge will be readily reducible so that the actual fascial defect can be easily defined by palpation. The patient may provide a history of vague abdominal pain associated with herniation and reduction. The list of differential diagnoses is short and includes abdominal wall varices associated with advanced cirrhosis, umbilical granulomas, and metastatic tumor implants in the umbilical soft tissue (Sister Joseph's node). In clinical practice, there is usually little doubt as to the diagnosis of umbilical hernia on physical examination.

While the majority of umbilical hernias will close spontaneously in the infant, the clinical spectrum varies widely in the adult. The hernia in the adult is often symptomatic and does not show a tendency to close without intervention. As the hernia contents increase in size, the overlying umbilical skin may become thin and ultimately ulcerated by pressure necrosis. The umbilical hernia with incarcerated omentum may present with significant tenderness on examination, despite the fact that bowel integrity is not at risk. Alternatively, an umbilical hernia may be found incidentally in the adult on physical examination. This hernia is usually small and any hernia contents are usually readily reducible. The small, asymptomatic, reducible hernia in the adult can be observed without the need for immediate intervention.

Patients with umbilical hernia secondary to chronic, massive ascites require special consideration. The repair of such hernias is associated with significantly increased morbidity and mortality. Fluid shifts leading to hemodynamic instability, infection, electrolyte imbalance, and blood loss are all considerable risks for the patient in this clinical scenario. Umbilical hernia recurrence is also common in this setting given the persistently increased intra-abdominal pressure. Thus, hernia repair in this population should be reserved for those with progressively symptomatic or incarcerated umbilical hernias.

Treatment

In the pediatric patient with a small umbilical hernia, a short curvilinear (smile) incision is made just inferior to the umbilicus in the typical skin crease. A skin flap is then raised cephalad using blunt dissection and low-level electrocautery. Dissection is carried through the subcutaneous tissues and down to the fascial level. The neck of the sac is then encircled with a hemostat. After the sac is dissected free of its umbilical attachments, it can be reduced or inverted completely into the peritoneal cavity or incised to explore the contents of the hernia sac. In this way, the redundant portion of the sac can be excised using electrocautery. The fascial defect is then closed transversely with interrupted sutures in a horizontal mattress fashion, and the skin of the umbilicus is tacked to the fascia layer using a single suture. This operation is usually performed under general anesthesia as a day-surgery procedure.

In the adult patient, most small umbilical hernia repairs are performed using local anesthesia with the possible addition of intravenous sedation. The approach is also through a curvilinear incision, placed transversely on the inferior border of the umbilicus or vertically on one curved edge of the umbilicus (Fig. 7-8). A skin flap is raised to elevate the umbilicus off the hernia sac. The sac is again dissected free of its fascial attachments to isolate the sac for complete reduction and to allow for an adequate width of fascia for suture closure. The sac contents are then reduced into the abdominal cavity and any excess sac can be excised. The defect is then closed with a strong, nonabsorbable suture (such as 0 polypropylene or nylon), usually in an interrupted fashion. The fascial edges are approximated through this technique. The traditional “vest-over-pants” technique originated by Mayo is less commonly utilized since overlapping fascial closures have been shown to weaken the overall wound strength in hernia repair.

In large defects that may close only with a significant degree of tension, a cone of polypropylene mesh can be fitted to fill the umbilical defect in place of a tissue repair. The mesh is then sutured circumferentially to the surrounding umbilical fascia to prevent migration. Newer mesh products contain polypropylene mesh or polyester mesh in combination with a bioabsorbable layer so that they can be placed in contact with the bowel without the formation of significant adhesions. These products can be very useful in the treatment of umbilical and other ventral hernias where mesh adherence to bowel is a concern.

An epigastric hernia is a defect in the abdominal wall in the midline junction of the aponeuroses of the abdominal wall musculature from the xiphoid process superiorly to the umbilicus inferiorly. The region of this midline raphe is termed the linea alba, and the rectus muscles are situated just lateral to the linea alba. In this area, there is no muscle layer to protect against herniation of intra-abdominal contents through defects in the midline fascia. A paraumbilical hernia is an epigastric hernia that borders on the umbilicus.

History

The epigastric hernia was first described by Villeneuve in 1285, but the term “epigastric hernia” was only first used to describe this condition in 1812 by Leville. The first successful repair of an epigastric hernia was reported in 1802 by Maunior.

Incidence

Estimates of the frequency of epigastric hernia in the general population range from 3% to 5%. It is most commonly diagnosed in middle age, and congenital epigastric hernias are uncommon. The condition is more common in males by a ratio of 3:1. Twenty percent of epigastric hernias may be multiple, although most are associated with one dominant defect.

Anatomy and Etiology

The cause of epigastric hernia is largely unknown. Since the condition does not predominate in children, it is unlikely that the defect is entirely congenital in origin. Rather, the hernia is likely the result of multiple factors, such as a congenitally weakened linea alba from a lack of decussating midline fibers and subsequent increase in intra-abdominal pressure, surrounding muscle weakness, or chronic abdominal wall strain.

The midline defect is usually elliptical in nature, with the long axis oriented transversely. The width of the defect is generally a few millimeters to several centimeters, and larger defects are rare. In most cases, the hernia is filled by a small amount of preperitoneal fat only and no peritoneal sac is present. The hernia will often not be seen on laparoscopy owing to the lack of peritoneal involvement through the hernia defect. Epigastric hernias that involve a peritoneal sac usually contain only omentum and rarely small intestine.

Clinical Manifestations

Epigastric hernia is often asymptomatic and represents a chance finding on physical examination. Patients with symptomatic hernias complain of vague abdominal pain above the umbilicus that is exacerbated with standing or coughing and relieved in the supine position. Severe pain may be secondary to incarceration or strangulation of preperitoneal fat or omentum. Bowel strangulation in epigastric hernias is a rare finding.

On examination, the hernia is diagnosed by palpating a small, soft, reducible mass in the midline superior to the umbilicus. The mass may protrude with a Valsalva maneuver or with standing. Palpation can be especially difficult in the obese patient. Rarely, imaging is needed to confirm the diagnosis, and computed tomography of the abdomen is the preferred technique.

Treatment

As illustrated in Fig. 7-9, operative repair of the epigastric hernia can most often be performed as a day-surgery procedure under local anesthesia. General anesthesia should be reserved for the complicated patient, a very large hernia, or the pediatric population. The herniated contents are exposed through a small midline vertical or transverse incision. The defect in the linea alba and the surrounding fascia are cleared of subcutaneous fat. Effort is made to identify a peritoneal sac protruding through the defect. If identified, a small sac can be simply inverted back within the abdominal cavity. Alternatively, a larger sac can be opened, its contents reduced, and any excess peritoneum excised. It is usually not necessary to perform formal closure of the peritoneal sac. The defect is then closed transversely with a few interrupted sutures of polypropylene or nylon, taking generous bites of surrounding fascia.

This repair usually suffices with minimal recurrence. In general, it is not necessary to reconstruct the linea alba for a single epigastric hernia. Most patients will not develop a subsequent epigastric hernia at a separate site, and repair of an epigastric hernia is a minor ambulatory procedure that can be repeated easily if necessary.

An obturator hernia is one of the rarest forms of hernia, and most surgeons will see few in an entire career. An obturator hernia occurs when there is protrusion of intra-abdominal contents through the obturator foramen in the pelvis.

Incidence

The true incidence of obturator hernia is unknown. The largest reported series includes only 43 patients diagnosed with obturator hernia over a 30-year period.34 It is thought that less than 1% of mechanical bowel obstructions arise from strangulated obturator hernias. The hernia is much more common in females, with a female:male ratio of 6:1. The gender discrepancy is often explained by differences in female pelvic anatomy, including a broader pelvis, a wide obturator canal, and the increase in pelvic diameter brought about by pregnancy. Most cases of obturator hernia present in the seventh and eighth decades, and this condition is clearly associated with advanced age. Bilateral obturator hernias have been reported in 6% of cases.

Anatomy

The obturator foramen is formed by the ischial and pubic rami (Fig. 7-10). The obturator membrane covers the majority of the foramen space, except for a small portion through which the obturator vessels and nerve pass. These vessels traverse the canal to leave the abdominal cavity and enter the medial aspect of the thigh. The boundaries of the obturator canal are the obturator groove on the superior pubic ramus superiorly and the upper edge of the obturator membrane inferiorly. The canal is approximately 3 cm in length, and the obturator vessels and nerve lie posterolateral to the hernia sac in the canal. The hernia sac usually takes the shape of the canal so that it is long and narrow before ballooning in the upper thigh. The hernia lies deep to the pectineus muscle and therefore is difficult to palpate on examination. Small bowel is the most likely intra-abdominal organ to be found in an obturator hernia, although rare cases have been reported of the appendix, Meckel's diverticulum, omentum, bladder, and ovary incarcerated in the hernia.

Clinical Manifestations

Obturator hernia is associated with four cardinal findings that assist in the difficult diagnosis. Rarely do all four physical findings occur together. The most common clinical manifestation is intestinal obstruction, which occurs in over 80% of patients. This is often in the form of acute obstruction secondary to hernia strangulation.35 The second most common finding is the Howship–Romberg sign, seen in about one-half of patients with obturator hernia. With this sign, patients characteristically complain of pain along the medial surface of the thigh that may radiate to the knee and hip joints. The finding is likely associated with compression of the obturator nerve between the canal and the hernia sac. The adductor reflex in the thigh may also be weakened or lost secondary to motor dysfunction from an entrapped obturator nerve. The third finding, observed in 30% of patients, is a history of repeated episodes of bowel obstruction that pass quickly and without intervention. This is likely due to periodic incarceration of the hernia sac in the obturator canal. Finally, a fourth finding is a palpable mass in the proximal medial aspect of the thigh at the origin of the adductor muscles. The palpable mass is only found in an estimated 20% of patients with obturator hernia. The mass is best palpated with the thigh flexed, abducted, and rotated outward.

In rare cases, ecchymoses may be noted in the upper medial thigh due to effusion from the strangulated hernia contents. The obturator hernia mass may also be palpated laterally on a vaginal examination.

Treatment

The only treatment for obturator hernia is surgical repair. All obturator hernias should be operated on soon after diagnosis given the high risk for bowel incarceration and strangulation. There is no role for conservative management given the location of the hernia and the fact that the strangulated obturator hernia is difficult to diagnose. A preoperative diagnosis of obturator hernia is rare indeed, and a diagnosis prior to presentation with bowel obstruction is even more uncommon. The typical case of obturator hernia presents as an acute small bowel obstruction with evidence of ischemic bowel on examination, laboratory analyses, or imaging. Therefore, obturator hernia repair is often performed as a surgical emergency via a midline laparotomy.

There are three general operative approaches for obturator hernia repair: the lower midline transperitoneal approach, the lower midline extraperitoneal approach, and the anterior thigh exposure.

The lower midline transperitoneal approach is the most common method for repair of obturator hernias since most cases are encountered unexpectedly during exploratory laparotomy for small bowel obstruction of unknown etiology. Following laparotomy, the dilated small bowel is run deep into the pelvis where it is found to enter the obturator canal alongside the obturator vessels and nerve. A careful attempt should be made to reduce the incarcerated bowel with gentle traction. This maneuver may be augmented by palpation on the medial inner thigh to push the hernia sac into the abdominal cavity from the outside. This is difficult to perform without assistance since the thigh is rarely sterilely prepared for the exploratory laparotomy unless a preoperative diagnosis of obturator hernia has been made. The pelvic side of the obturator canal has a rigid opening that cannot be digitally dilated, making reduction of the hernia sac more difficult. If traction alone does not allow reduction of the bowel, the obturator membrane can be carefully incised from anterior to posterior to facilitate exposure. Care should be taken to avoid injury to both the incarcerated bowel and the obturator vessels. If these maneuvers are unsuccessful, a counter incision can be made in the medial groin to facilitate reduction from both sides of the canal. Once the hernia has been reduced, the intestine is assessed for viability and resected as needed. The hernia opening is then closed around the obturator vessels with a running layer of polypropylene or nylon suture applied in the thin layer of fascia that encircles the inner circumference of the canal. Alternatively, in a clean case without bowel contamination, a piece of mesh can be placed over the obturator foramen. Some hernia surgeons suture the mesh to Cooper's ligament to avoid migration.

The midline extraperitoneal approach is used when the diagnosis of obturator hernia has been made preoperatively. It allows complete exposure of the opening of the obturator canal. The incision is made in the midline from the umbilicus to the pubis. The preperitoneal plane is entered deep to the rectus muscle, and the bladder is peeled from the peritoneum. The space is opened so that the superior pubic ramus and the obturator internus muscle are exposed. The hernia sac is seen as a projection of peritoneum passing inferiorly into the obturator canal. The sac is incised at the base, the contents are reduced, and the neck of the sac is transected. Any remaining distal sac in the canal is extracted by traction or with long forceps. The internal opening to the obturator canal is closed with a continuous suture as described above. The bites of tissue should include the periosteum of the superior pubic ramus and the fascia on the internal obturator muscle. Care must be exercised at all times to avoid injury to the obturator vessels and nerve that run alongside the hernia defect. In addition to or in place of the suture closure of the obturator defect, preperitoneal mesh placement has been described to cover the defect.

The thigh approach begins with a vertical incision in the upper medial thigh placed along the adductor longus muscle (Fig. 7-11). The muscle is retracted medially to expose the pectineus muscle, which is cut across its width to expose the sac. The sac is carefully incised, the contents inspected and reduced if viable, and the sac is excised. The hernial opening is closed with a continuous suture layer. If the bowel contents within the hernia sac do not appear viable, it is difficult to perform an adequate small bowel resection through the thigh incision and therefore midline laparotomy is usually performed.

Laparoscopic transperitoneal and extraperitoneal approaches have been recently described for obturator hernia repair with placement of prosthetic mesh to close the obturator opening.36

Results

Mortality after obturator hernia repair has been much higher than with other hernias because it is associated with acute bowel obstruction in an elderly population with multiple comorbidities. Recent data show a mortality of less than 5% and a 25% incidence of small bowel resection during obturator hernia repair.34 These reports emphasize the benefit in accuracy in the modern era afforded by computed tomographic imaging techniques. Recurrence rates are low in published series, although long-term follow-up has proved difficult in this patient population.

Hernias of the perineum are rare and composed of protrusions of the intra-abdominal contents through a weakened pelvic floor. They may also be termed pelvic hernias, ischiorectal hernias, pudendal hernias, subpubic hernias, or hernias of the pouch of Douglas. Perineal hernias should be differentiated from the more common rectocele or cystocele, which are related to pelvic floor relaxation, most often from childbirth, and do not represent true hernias.

Primary perineal hernias are extremely rare. The first reported case was by Scarpa in 1821. Secondary, or postoperative, perineal hernias are more commonly seen and occur in patients status postabdominoperineal resection in which the pelvic musculature is dissected to resect the distal rectum.

Etiology

Primary perineal hernias occur in the older population, usually between the fifth and seventh decades of life. They are at least five times more common in women than in men, and this is thought to be associated with the broader pelvic floor in the female and long-term effects of pregnancy and childbirth. Factors that may predispose to a primary perineal hernia include a deep or elongated pouch of Douglas, obesity, chronic ascites, history of pelvic infection, and obstetric trauma.

Postoperative perineal hernia may occur in patients who have undergone abdominoperineal resection or pelvic exenteration. It is thought to form as a result of excision of the levator ani musculature and its surrounding fascia with incomplete repair of the pelvic floor. An excision of the coccyx is thought to be an additional aggravating factor in hernia formation. As in primary perineal hernias, women are affected more often than men. The condition, while more common than the primary perineal hernia, remains rare.

Anatomy

The pelvic floor is formed by the levator ani and iliococcygeus muscles and their fascia. The pelvic outlet is bounded by the pubic symphysis and the subpubic ligament anteriorly, the pubic rami and ischial tuberosities laterally, and the coccyx and sacrotuberous ligaments posteriorly. The outlet is divided into anterior and posterior divisions by the superficial transversus perinei muscles. The anterior space is termed the urogenital triangle, and the posterior space is termed the ischiorectal fossa. Anterior and posterior perineal hernias are named according to the location of the hernia defect and subsequent sac protrusion, as shown in Fig. 7-12.

The anterior perineal hernia occurs almost exclusively in women. The sac enters in front of the broad ligament and lateral to the bladder, emerging anterior to the transversus perinei musculature. The sac may pass between the ischiopubic bone and the vagina, thereby producing a swelling in the posterior portion of the labia majus. Posterior perineal hernias are found in both genders but remain more common in women. In men, the hernia sac emerges between the bladder and the rectum to present as a bulge in the perineum. In women, the hernia enters between the rectum and the uterus to pass posteriorly to the broad ligament. In this space, the hernia can push forward to present as a bulge in the posterior vagina or emerge posteriorly into the rectum. The hernia can pass through the levator ani muscle or between it and the iliococcygeus muscle. A lateral pelvic hernia may occur through the hiatus of Schwalbe when the levator ani muscle is not firmly attached to the internal obturator fascia. This type of perineal hernia can present anteriorly in the labium majus or posteriorly in the ischiorectal fossa.

Clinical Manifestations

The patient with a perineal hernia most often complains of a soft protuberance that is reduced in the recumbent position. In cases of anterior perineal hernia, minor urinary retention or discomfort may be reported. A soft bulge may be noted in the posterior vagina or the labia, thereby interfering with labor or intercourse. In posterior perineal hernias, the patient may describe a mass protruding between the gluteus muscles, thereby making sitting difficult after the hernia has emerged in a standing position. The patient may rarely complain of constipation or the feeling of incomplete defecation.

In general, symptoms from a perineal hernia are mild, and strangulation is rare since the hernia defect in the pelvic floor is large and surrounded by soft tissue and atrophied musculature. Rectal prolapse may be confused with a posterior perineal hernia, although the two can exist concomitantly. The perineal hernia, even when the defect involves the posterior pelvic floor, will present as a bulge anterior to the prolapsed rectum.

Treatment

Three options for repair of the perineal hernia exist including the transperitoneal, perineal, and the combined approaches. The transperitoneal approach is the preferred method for complete repair. In this technique, a lower midline abdominal incision is performed and the bowel retracted out of the pelvis with the patient in the Trendelenburg position. A defect in the muscular lining of the pelvic floor will be noted, and any remaining bowel in the defect can usually be easily reduced. The sac is everted and excess sac tissue can be excised. While small defects in the pelvic floor can be closed with interrupted sutures of nylon or polypropylene, this is usually not an adequate repair given the poor strength of the atrophied tissue that often surrounds the hernia defect. Therefore, a repair with a large piece of nonabsorbable mesh is preferred and is usually tacked down to the pelvic floor tissues with interrupted nonabsorbable monofilament sutures.

The perineal approach to hernia repair is more direct and avoids a laparotomy but suffers from inadequate exposure of the actual hernia defect. In this technique, a transverse or longitudinal incision is made directly over the site of the hernia bulge. The sac is identified and dissected free of its attachments to the surrounding pelvic musculature and fascia. The sac is then excised and its contents are reduced within the abdominal cavity. The defect is repaired with interrupted nonabsorbable suture, as the exposure is usually not wide enough for proper placement of mesh. While this approach may be suitable for a small hernia defect in an unhealthy patient, the risk of recurrence is high.

In extraordinary cases in which the hernia contents cannot be reduced during a transperitoneal repair, a combined approach with dissection from the perineum can be considered. The actual repair of the hernia defect should take place from within the abdomen to obtain optimal exposure and facilitate placement of mesh to reinforce the closure.

Postoperative perineal hernia repairs may also be repaired by either a transperitoneal or perineal approach. However, the transperitoneal approach is preferred in this scenario, as the hernia contents may be difficult to completely reduce secondary to postoperative adhesion formation. In addition, given the previous operative dissection, the pelvic floor is already weakened and mesh placement is often necessary to achieve an adequate, tension-free closure of the defect.

A spigelian hernia occurs along the semilunar line, which traverses a vertical space along the lateral rectus border from the costal margin to the pubic symphysis. Adriaan van der Spieghel (1578–1625), a pupil of Fabricius of Padua and a professor of anatomy and surgery, was the first to accurately describe the semilunar line. He described the spigelian fascia as the aponeurotic structure between the transversus abdominis muscle laterally and the posterior rectus sheath medially. This fascia is what makes up the semilunar line, and it is through this fascial layer that a spigelian hernia forms.

Spigelian hernia is well described, and almost 1000 cases have been reported in the medical literature. It is likely that more of these hernias will be diagnosed, as the spigelian hernia is readily seen on computed tomography scans as well as laparoscopic views of the anterior abdominal wall.

Anatomy

In practice, the semilunar line is taken as the lateral border of the rectus sheath. Spieghel originally intended this structure to represent the line of transition from the muscular fibers of the transversus abdominis muscle to the posterior aponeurosis of the rectus. The semilunar line runs from the ninth rib cartilage superiorly to the pubic tubercle inferiorly. The spigelian fascia varies in width along the semilunar line, and it gets wider as it approaches the umbilicus. The widest portion of the spigelian fascia is the area where the semilunar line intersects the arcuate line of Douglas (the linea semicircularis; Fig. 7-13). It is in this region, between the umbilicus and the arcuate line, where more than 90% of spigelian hernias are found.37 It is thought that since the spigelian fascia is widest at this point, it is also weakest in this region. Below the arcuate line, all of the transversus abdominis aponeurotic fibers pass anterior to the rectus muscle to contribute to the anterior rectus sheath, and there is no posterior component of the rectus sheath. The rearrangement of muscle and fascial fibers at the intersection of the arcuate and semilunar lines is thought to cause an area of functional weakness that is predisposed to hernia formation. Hernias at the upper extremes of the semilunar line are rare and usually not true spigelian hernias since there is little spigelian fascia in these regions.

As the hernia develops, preperitoneal fat emerges through the defect in the spigelian fascia bringing an extension of the peritoneum with it (Fig. 7-14). The hernia usually meets resistance from the external oblique aponeurosis, which is intact and does not undergo rearrangement of its aponeurotic fibers at the arcuate line. For this reason, almost all spigelian hernias are interparietal in nature, and only rarely will the hernia sac lie in the subcutaneous tissues anterior to the external oblique fascia. This fact makes the accurate diagnosis of spigelian hernias more challenging. The hernia also cannot develop medially due to resistance from the intact rectus muscle and sheath. Therefore, a large spigelian hernia is most often found lateral and inferior to its defect in the space directly posterior to the external oblique muscle.

Clinical Manifestations

The patient most often presents with a swelling in the middle to lower abdomen just lateral to the rectus muscle. The patient may complain of a sharp pain or tenderness at this site. The hernia is usually reducible in the supine position. However, up to 20% of spigelian hernias will present incarcerated, and for this reason operative repair is mandatory once the hernia is confirmed on diagnosis. The reducible mass may be palpable, even if it sits below the external oblique musculature.

When the diagnosis is unclear, radiologic imaging may be necessary. Ultrasound examination has been shown to be the most reliable and easiest method to assist in the diagnostic workup. Testa and colleagues found that abdominal wall ultrasonography was accurate in 86% of cases of spigelian hernia.38 If the hernia is fully reduced during examination and no mass is palpable, ultrasound evaluation can show a break in the echogenic shadow of the semilunar line associated with the fascial defect. Ultrasound can also identify the nonreduced hernia sac passing through the defect in the spigelian fascia. Computed tomographic scanning of the abdomen will also confirm the presence of a spigelian hernia. As described above, the anatomy of the spigelian hernia should make it readily apparent on laparoscopic evaluation of the anterior abdominal wall.

Treatment

The treatment for spigelian hernia is operative repair once the diagnosis has been confirmed, given the risk for incarceration. This is usually performed under general anesthesia given the need for splitting of the external oblique muscle. A transverse incision is made directly over the palpable mass or fascial defect. A hernia in the subcutaneous space will reveal itself immediately, and an interparietal hernia will require further dissection. In this way, the external oblique fascia is incised and the external oblique muscle is split to identify the sac posterior to the muscle. The sac is freed from its surrounding attachments until the neck is isolated. The sac is opened, the intra-abdominal contents reduced, and the sac is either excised if sizable or simply inverted into the intra-abdominal cavity. Suturing the medial and lateral edges of the internal oblique and transversus abdominis aponeuroses closes the fascial defect. Essentially, this approximates the internal oblique and transversus fascia laterally to the rectus sheath medially. Prosthetic mesh is not required for this repair, although the use of mesh plugs to close the hernia defect has been described.38 Recurrence is uncommon and the operation is usually well tolerated.

The lumbar region is bordered by the twelfth rib superiorly, the iliac crest inferiorly, the erector spinae muscles of the back posteriorly, and a vertical line between the anterior tip of the twelfth rib and the iliac crest anteriorly. The region contains two anatomic triangles, through which the rare lumbar hernia can form. The inferior lumbar triangle of Petit is the more common of the two. Its anterior border is the posterior edge of the external oblique muscle, the posterior border is the anterior extent of the latissimus dorsi muscle, and the inferior border is the iliac crest (Fig. 7-15). The anterior floor of the canal formed by this triangle is the lumbar fascia. Occasionally, the lower border of the latissimus dorsi muscle overlaps the external oblique muscle, and in this setting the triangle is absent. The superior lumbar triangle of Grynfeltt (see Fig. 7-15) is deeper and is bounded by the twelfth rib and the serratus posterior inferior muscle, the posterior border of the internal oblique muscle, and by the quadratus lumborum and erector spinae muscles posteriorly. The floor of the superior triangle is composed of transversalis fascia and the entire triangular space is covered posteriorly by the latissimus dorsi muscle.

Congenital lumbar hernias are rare, but case reports can be found in the literature. Lumbar hernias most commonly present in adults older than 50 years of age. Two-thirds of the cases are reported in males, and left-sided hernias are thought to be more common. Bilateral lumbar hernias have been reported. Acquired lumbar hernias have been associated with back or flank trauma, poliomyelitis, back surgery, and the use of the iliac crest as a donor site for bone grafts.

Strangulation is rare in lumbar hernias since at least two of the three boundaries for the hernia defect are soft and muscular in origin. The hernia tends to increase in size over time and may assume large proportions and overhang the iliac crest. Symptoms range from a vague dullness in the flank or lower back to focal pain associated with movement over the site of the defect. On physical examination, a soft swelling in the lower posterior abdomen will be found that is usually reducible without difficulty. The hernia will increase in size with straining or a standard Valsalva maneuver. Ultrasonographic or computed tomographic imaging is usually obtained in the patient with a suspected lumbar hernia to confirm the diagnosis.

Operative repair of the lumbar hernia is performed with the patient under general anesthesia and in a modified lateral decubitus position. A kidney rest can be used to widen the lumbar space between the twelfth rib and iliac crest. An oblique skin incision is made in the region of the hernia and the sac is identified. The dissection may require takedown of the latissimus dorsi muscle to reach the deeper superior lumbar triangle. Once the sac is identified, it is opened and the contents are carefully reduced. The empty sac can then be inverted or simply excised. While complicated procedures for lumbar hernia closure utilizing muscle flaps and grafts have been described, a small defect surrounded by healthy tissue can usually be closed primarily with an interrupted or continuous layer of nylon or polypropylene suture. If a large defect is found or the tissues appear weak, the hernia may be repaired with a large sheet of prosthetic nonabsorbable mesh placed between the peritoneal layer and the abdominal wall musculature. To prevent migration, the mesh is usually fixed to the peripheral tissues by a series of interrupted nonabsorbable sutures.

Recently, minimally invasive approaches to repair of lumbar hernias have been reported. These involve either intraperitoneal laparoscopy necessitating takedown of the lateral peritoneal reflection of the colon to facilitate exposure of the hernia defect,39 or retroperitoneoscopy in which the lateral retroperitoneal space is entered and insufflated.40 Initial results with the minimally invasive approaches are encouraging, although these case series contain small numbers of subjects.

A sciatic hernia is defined as a protrusion of peritoneum and intra-abdominal contents through the greater or lesser sciatic notch (Fig. 7-16). The greater sciatic notch is traversed by the piriformis muscle, and hernia sacs can protrude either superior or inferior to this muscle. There are classically three variants of the sciatic hernia that are defined by their anatomic site of exit from the pelvis. The suprapiriform defect is by far the most common and is thought to represent 60% of cases of sciatic hernia. Infrapiriform hernias are found in approximately 30% of cases, and subspinous hernias (through the lesser sciatic foramen) occur in 10% of cases.

The hernia sac passes laterally, inferiorly, and ultimately posteriorly to lie deep to the gluteus maximus muscle. While case reports of this rare hernia exist in the pediatric age group, the majority of sciatic hernias are found in the adult population. The patient complains of pain deep in the buttock that may radiate down the leg in the sciatic nerve distribution. Alternatively, the patient may report a lump in the buttock or infragluteal area that is painful and tender. Rarely, ureteral obstruction occurs because the ipsilateral ureter is contained within the hernia contents. Physical examination often reveals a reducible mass deep to the gluteus maximus, although the actual hernia defect is rarely palpable given the anatomic depth and the thickness of the buttock musculature. Incarceration of the hernia can occur, and sciatic hernia has been known to present with bowel obstruction.

The treatment of a sciatic hernia is surgical. Both transperitoneal and transgluteal approaches have been described in depth, and the transperitoneal technique is preferred in the setting of bowel obstruction or incarceration. Rarely, a combined approach will be necessary to fully reduce the hernia contents. Even in the setting of incarceration, the bowel can usually be reduced from within the hernia with gentle traction. When necessary with the transperitoneal approach, the defect can be dilated with manual manipulation or the piriformis muscle may be partially incised. Full visualization of the structures is necessary and great care must be taken to avoid injury to the many nerves and vessels found in this region. After the sac has been excised, the defect is repaired using interrupted nonabsorbable suture or a prosthetic mesh plug or patch for larger hernia defects.

The posterior or transgluteal technique can be utilized for uncomplicated, reducible sciatic hernias diagnosed preoperatively. With this method the patient is placed in the prone position. The gluteus maximus muscle is approached through a gluteal incision starting at the posterior edge of the greater trochanter and is detached at its origin to expose the hernia defect. This exposure allows visualization of the piriformis muscle, the gluteal vessels and nerve, and the sciatic nerve. The sac is then isolated and opened. Following reduction of the hernia contents, the defect can be sutured closed using large nonabsorbable suture or repaired with a prosthetic mesh.

A postoperative ventral abdominal wall hernia, more commonly termed incisional hernia, is the result of a failure of fascial tissues to heal and close following laparotomy. Such hernias can occur after any type of abdominal wall incision, although the highest incidence is seen with midline and transverse incisions.41 Postoperative ventral hernias following paramedian, subcostal, McBurney, Pfannenstiel, and flank incisions have also been described in the literature. Laparoscopic port sites may also develop hernia defects in the abdominal wall fascia.

As the approximated fascial tissue separates, the bowel and omentum herniate through the opening, covered by a peritoneal sac. These hernias can increase in size to enormous proportions, and giant ventral hernias can contain a significant amount of small or large bowel. At the extreme end of the ventral hernia spectrum is the giant incisional hernia that leads to loss of the abdominal domain, which occurs when the intra-abdominal contents can no longer lie within the abdominal cavity.

Incidence and Etiology

Incisional hernias have been reported in up to 20% of patients undergoing laparotomy. Modern rates of incisional hernia range from 2% to 11%.42–44 It is estimated that approximately 100,000 ventral incisional hernia repairs are performed each year in the United States alone. The incidence seems to be lower in smaller incisions so that laparoscopic port site hernias are much less common than hernias following large midline abdominal incisions. While it was once believed that the majority of incisional hernias presented within the first 12 months following laparotomy, longer-term data indicate that at least one-third of these hernias will present 5–10 years postoperatively.

Multiple risk factors exist for the development of an incisional hernia. Some of these risks are under the control of the surgeon at the initial operation, while many others are patient specific or related to postoperative complications. Patient-specific risks for postoperative ventral hernia include advanced age, malnutrition, presence of ascites, corticosteroid use, diabetes mellitus, cigarette smoking, and obesity.41,45–47 Emergency surgery is known to increase the risk of incisional hernia formation. Wound infection is believed to be one of the most significant prognostic risk factors for development of an incisional hernia.41,48 It is for this reason that many surgeons advocate aggressive and early opening of the skin closure to drain any potential infection at the fascial level. Postoperative sepsis has also been identified as a risk for subsequent incisional hernia.

Technical aspects of wound closure likely contribute to incisional hernia formation. Wounds closed under excessive tension are prone to fascial closure disturbance. Therefore, a continuous closure is advocated to disperse the tension throughout the length of the wound. In this way, 1 cm bites of fascia on either side of the incision are taken with each pass of the suture and the suture is advanced 1 cm at a time along the length of the incision. The type of incision may affect hernia formation. Studies have shown that transverse incisions are associated with a reduced incidence of incisional hernia compared to midline vertical laparotomies, although the data are far from conclusive.46,49

Clinical Manifestations

The patient with an incisional hernia will complain of a bulge in the abdominal wall originating deep to the skin scar. The bulge may cause varying degrees of discomfort or may present as a cosmetic concern. Symptoms will usually be aggravated by coughing or straining as the hernia contents protrude through the abdominal wall defect. In large ventral hernias, the skin may present with ischemic or pressure necrosis leading to frank ulceration. Presentation of the incisional hernia with incarceration causing bowel obstruction is not uncommon. This may be associated with a history of repeated mild attacks of colicky dull abdominal pain and nausea consistent with incomplete bowel obstruction.

On examination the hernia is usually easy to identify and the edges of the fascial defect can often be defined by palpation. The entire abdominal wall along the length of the incision should be inspected and palpated carefully, as multiple hernias are often present in the setting of an incisional hernia. In the obese patient with a suspected incisional hernia that cannot be confirmed on examination, computed tomography of the abdomen is the best way to visualize intra-abdominal contents within the hernia sac. In extreme instances, laparoscopy may be required to diagnose a hernia defect that only intermittently contains intra-abdominal contents.

Treatment

The treatment of ventral incisional hernia is operative repair, and three general classes of operative repair have emerged in the modern era. These techniques include primary suture repair of the hernia, open repair of the hernia with prosthetic mesh, and laparoscopic incisional hernia repair. The major sequela from operative repair of the incisional hernia is hernia recurrence, and there are convincing data that placement of mesh to repair the hernia defect has decreased the high recurrence rate historically associated with primary suture repair to less than 25%.50,51 Many advocates of the operation believe that laparoscopic incisional hernia repair will have the lowest rate of hernia recurrence and definitive studies are underway to assess this question.

In general, primary repair of incisional hernias can be performed for hernia defects less than 4 cm in diameter with strong, viable surrounding tissue. For larger hernias or hernias associated with multiple small defects, mesh repair is indicated. Even with mesh repair, hernia recurrence remains a significant complication. In one multicenter trial, for example, 200 patients were randomly assigned to suture or mesh repair of a primary hernia or a first recurrence of hernia at the site of a vertical midline incision.52 The 3-year cumulative rates of recurrence among patients who had suture or mesh for repair of a primary hernia were 43% and 24%, respectively. The rates of second recurrence were 58% and 20%, respectively.

Primary Suture Repair

The operation is best performed with the patient under general anesthesia to achieve full relaxation of the abdominal wall musculature. The skin is opened through the previous incision and dissection is performed through the subcutaneous tissues. Care should be taken as the level of the anterior rectus sheath is approached since portions of the sac and its contents may lie at this level. The sac is identified and cleared of its attachments to the fascia using electrocautery. In this way, any peritoneal attachments to the anterior abdominal wall in the vicinity of the hernia are taken down and the sac is fully reduced into the abdominal cavity. The fascia is then cleared of soft tissue both anteriorly and posteriorly for at least a 3–4 cm margin. This allows for a margin of healthy fascia to bring together in the midline with suture closure.

The fascia is then closed using an interrupted layer of nonabsorbable suture by taking large bites of the clean fascia on both sides of the defect. The sutures are usually placed sequentially and then tied after the entire layer of suture has been placed. The fascia is then inspected to confirm that no additional defects are present and that the repair sutures are not pulling through the tissue due to excessive tension. The skin is closed over the fascia using either staples or a running subcuticular layer. If the hernia contents have created a large pocket in the soft tissue above the anterior fascia, placement of a closed suction drain for evacuation of early seroma fluid can be considered.

If there is tension upon attempted closure of the abdominal wall, a separation of components can be performed in order to mobilize the fascia toward the midline (Fig. 7-17). This technique begins with the mobilization of the skin and soft tissue off of the underlying fascia. The fascia of the external oblique is then incised lateral to the rectus abdominis and the external oblique is dissected free from the internal oblique in a relatively avascular plane. This alone allows for significant mobilization of the abdominal wall toward the midline. Should additional mobilization be required, the posterior rectus sheath can be incised in a longitudinal fashion to allow the overlying rectus abdominis and anterior rectus sheath to slide even further toward the midline.53 This technique allows for closure of complex or infected abdominal wounds without the need for implantation of any foreign material.

Over the last 10–15 years, the introduction of component separation as a method for repairing ventral hernias has gained increasing popularity due to its conceptual purity and its overwhelming success. Recent series including those by Ko54 has reported his experience in 200 patients who underwent this procedure over the course of slightly over 1 decade. The overall recurrence rate was 21%. Supportive polypropylene mesh was employed to cover the defect. In the process of performing this procedure, bilateral releases of the external oblique muscle are performed and the fascia is mobilized, thereby allowing medial movement of the rectus muscle. This brings the rectus muscle closer to the midline and achieves a muscular closure of the midline which can be reinforced or strengthened by the placement of either biologic or manufactured mesh. Mesh is not a necessary portion of the component separation technique although it is frequently used. The variety of different types of mesh includes polypropylene, polyester, and other both biologic and nonbiologic materials. Primary repair using no mesh but using the component separation technique had a 22.5% recurrence rate, while recurrence rates using cadaveric biomesh were 33.3%. Those in whom low-weight polypropylene was used had a 0% recurrence rate. Part of the study looked at demographic factors and noted that elevated body mass had a significant risk of recurrence. This was true at less than a p value of 0.005 and also notable most commonly in patients with a BMI of greater than 25.

Mesh Repair

The use of sheets of nonabsorbable prosthetic mesh placed across the incisional hernia defect and sutured to the abdominal wall is routinely employed in the modern era. It is associated with a low incidence of perioperative complications and lower rates of recurrence than open, nonmesh repairs.

Many variations of mesh repair for the incisional hernia have been described (Fig. 7-18). The mesh is cut to the shape of the hernia defect with a margin added circumferentially around the mesh to suture to healthy surrounding fascia. The mesh is sutured to the fascial layer either deep to the peritoneum or between the peritoneum and the abdominal wall. Alternative techniques have been described that suture pieces of mesh to fascia from both intra- and extraperitoneal planes.

The operation is performed under general anesthesia. The old scar is incised and the soft tissue dissected down to the level of the anterior rectus sheath. Here the defect is identified and the fascia is cleared of surrounding soft tissue attachments to allow a 3–4 cm rim of healthy fascia circumferentially. The sac is then freed from the fascia in order to reduce the hernia contents and prevent recurrence. This portion of the operation is often technically challenging, as significant adhesion formation may have occurred following the initial operation. It is often impossible to stay in an extraperitoneal plane in this situation, and dissection within the abdominal cavity may be necessary to fully excise the sac and reduce its contents. The mesh can now be placed either anterior to the fascia or posterior from within the intra-abdominal cavity. Effort should be made to protect the bowel from direct contact with the mesh patch, and a layer of omentum can often be placed between them. The mesh is sutured in an interrupted fashion in multiple sites throughout the entire circumference of the patch to ensure that any tension is distributed throughout the entire area of the repair. Large, nonabsorbable suture is used to affix the mesh to the fascia layer.

There are currently a variety of mesh products readily available for use in the repair of ventral incisional hernias. In general, these products can be grouped into those that are composed of synthetic materials and those that are composed of biologic materials. The synthetic meshes frequently incorporate either polypropylene or expanded polyfluorotetraethylene (ePTFE) in combination with some form of barrier to prevent adhesions to the bowel. While both polypropylene and ePTFE are used in the treatment of ventral hernias, they have significantly different properties. Polypropylene meshes are macroporous and allow for ingrowth of native tissue into the mesh, leading to incorporation. Conversely, ePTFE meshes are more microporous and do not promote as much ingrowth. This leads to less adhesions to ePTFE meshes, but also requires that there is adequate fixation in order to prevent disruption and thus recurrence. Biologic meshes are based on acellular dermal matrices from human, porcine, and fetal bovine sources. While the long-term outcomes for these meshes are currently being studied, the biologic meshes have been shown to be more resistant to infection than their synthetic predecessors and are more appropriate for use in infected or contaminated fields.55

Biologic grafts derive from two basic materials. The first is human tissue and the second is animal tissue. Their use in hernias is confined primarily to dirty or contaminated fields in which placement of a prosthetic mesh might increase the chance of infection. It is well recognized that primary closure of incisional hernias carries a high recurrence rate and that removal of prosthetic mesh in an infected field and attempts to primarily close these defects will invariably lead to recurrence. As a result, enthusiasm has recently grown for the use of biologic grafts that may enhance the repair, decrease the chances of infection, and provide a bridge to a clean wound. If recurrence subsequently develops, it can be managed with a prosthetic material. The biologic grafts have different characteristics depending on the tissue of origin. Grafts can be based on dermis, either human or porcine, or on submucosa. The dermis-based grafts are prepared in such a way as to allow collagen and elastin to remain within the matrix. Although these materials have excellent resistance to infection, they do have the distinct disadvantage of weakening over time because of elastin breakdown. This can lead to eventration, recurrence, or the possibility of pseudorecurrence, which can occur as a result of the weakening of the elastin, increased compliance, and softening of the graft. Methods that are utilized to improve the durability of these grafts are the use of glutaraldehyde and hexamethylene diisocyanate, cross-linking agents which make the material, whether it is human or porcine, more resistant to breakdown by enzymatic degradation. This leads not only to greater durability but also to increasing the susceptibility of these grafts to microbiologic attack. Cross-linking limits the ability of the host to incorporate the graft and make it essentially a part of the native tissue.

Laparoscopic Repair

The evolution of ventral hernia repair has advanced from open mesh repair to the application of mesh repair to the laparoscopic approach. In this technique, the defect is repaired posteriorly and no dissection within the scarred layer of anterior fascia is required. The laparoscopic approach may also allow for identification of additional hernia defects in the anterior abdominal wall during the repair.

One of the challenging aspects of laparoscopic repair is port access into a peritoneal cavity that has been previously operated upon. In general, access can be obtained for needle insufflation via the left upper quadrant, placing the port along the anterior axillary line to avoid injury to the more laterally positioned spleen. Once insufflation has been achieved and instruments have been inserted, the next challenge is the extensive laparoscopic lysis of adhesions that is often necessary to gain exposure to the entire hernia defect. The goal of the adhesiolysis is to provide a 3–4 cm circumferential area of overlap for the mesh patch beyond the edge of the ventral hernia defect.

After the appropriate adhesions have been taken down and the fascial edges of the defect confirmed, the sac is retracted and excised from within the hernia. The outline of the defect is then drawn on the anterior abdominal wall. Edges of the defect at the skin level can be confirmed from within the abdominal cavity using the laparoscope. The mesh is then cut to fit this defect with a margin of 3–4 cm on each side to provide adequate coverage and to minimize tension. Nonabsorbable sutures are placed around the circumference of the mesh and tied, but not cut. The mesh is rolled so that the anterior surface lies inside the roll, and the mesh is inserted into the abdomen through a large 10- or 12-mm port.

Once inside the abdominal cavity, the mesh is unrolled and positioned. A transfascial suture passer can be introduced through small stab incisions placed around the marked border of the defect. The suture passer retrieves the long ends of the suture that has been previously placed in the mesh, and the ends are tied at the skin level at 4–6 points around the repair and buried with the subcutaneous tissue in the stab incision. This affixes the mesh patch to the fascia layers around the circumference of the patch. After all sutures have been tied and cut, laparoscopically placed tacks or staples can be used to further fasten the mesh to the anterior abdominal wall. Whether the strength of the repair is imparted by the transfascial sutures or the tacks or both remains controversial.

Complications

The major complication from open, nonmesh incisional hernia repair is recurrence. Rates of recurrence in this type of repair have approached 30–50% in some series. The risk of recurrence is likely related to the tension placed on the repair in large hernias, and for this reason, incisional hernias with a diameter greater than 4 cm should be repaired with mesh.

Open incisional hernia repairs using mesh can also suffer from hernia recurrence, although the risk is far less than that of the nonmesh technique. Several studies have shown that the risk of recurrence in incisional hernia repair with mesh is approximately 10%. Recurrence in this setting is usually secondary to the appearance of an additional, unrecognized hernia site or an improperly placed prosthesis that pulls away from the fascia edge of the repair. Hematoma or seroma formation may occur in the cavity left behind following a hernia repair. For this reason, closed suction drains may be placed if a large amount of dead space remains following the repair. The drains should be managed judiciously, however, since they may be placed in proximity to the prosthetic mesh, thereby increasing the chance of secondary infection. Wound infection and infection of the mesh can be grave complications, often necessitating removal of the mesh and application of an allogenic tissue graft. Wound infection in open mesh repairs is thought to approximate 5%.

The laparoscopic approach to incisional hernia repair shares the general complications of laparoscopy, including the potential for port-site herniation, vascular injury from trocar placement, and inadvertent bowel injury during laparoscopic adhesiolysis. The mesh placed during laparoscopic repair can also be prone to infection, although the incidence of mesh infection appears to be lower in laparoscopic than open mesh techniques. This may be related to the extensive tissue dissection required to place the mesh in the open procedure. Several nonrandomized studies have shown that the laparoscopic approach is associated with a low incidence of hernia recurrence, in the range of 0–11%.56 Seroma formation in the retained sac above the mesh may occur but usually resolves spontaneously.

There are numerous prospective studies that provide data for the individual techniques, but data are scarce in the comparison between open and laparoscopic mesh repairs for incisional hernia. Nonrandomized, retrospective studies have provided ample evidence that the laparoscopic approach is associated with fewer postoperative complications, a lower incidence of wound and mesh infections, a lower rate of recurrence in long-term follow-up, and shorter in-hospital stays.57 A recent meta-analysis pooled results from five separate randomized controlled trials comparing laparoscopic and open incisional hernia repairs.58 The authors found no significant differences in recurrence rates between the two groups, but the open repair was associated with significantly longer length of stay and postoperative complications compared to the laparoscopic group. Clearly, more studies are required to definitively determine which procedure is optimal; however, at this time both open and laparoscopic techniques appear to be safe and effective in the treatment of incisional hernias.