Chapter 37: Inguinal Hernias

1. Conservative management of asymptomatic inguinal hernias is acceptable.

2. A proficient understanding of groin anatomy is essential to successful inguinal hernia treatment.

3. Elective repair of inguinal hernias can be undertaken using an laparoscopic or open approach.

4. The use of prosthetic mesh as a reinforcement significantly improves recurrence rates, whether the repair is open or laparoscopic.

5. Recurrence, pain, and quality of life are important outcome factors.

6. Laparoscopic inguinal hernia repair results in less pain and faster recovery, yet requires specialized training and equipment.

Inguinal hernia repair is the most commonly performed operation in the United States, owing to a significant lifetime incidence and variety of successful treatment modalities. Approximately 800,000 cases were performed in 2003, not including recurrent or bilateral hernias.¹ Advancements in perioperative anesthesia and operative technique have made this an outpatient ambulatory operation with low recurrence rates and morbidity. Given this success, quality of life and the avoidance of chronic pain have become the most important considerations in hernia repair.

Approximately 75% of abdominal wall hernias occur in the groin. The lifetime risk of inguinal hernia is 27% in men and 3% in women.² Of inguinal hernia repairs, 90% are performed in men and 10% in women. The incidence of inguinal hernias in males has a bimodal distribution, with peaks before the first year of age and after age 40. Abramson demonstrated the age dependence of inguinal hernias in 1978. Those age 25 to 34 years had a lifetime prevalence rate of 15%, whereas those age 75 years and over had a rate of 47% (Table 37-1).³ Approximately 70% of femoral hernia repairs are performed in women; however, inguinal hernias are five times more common than femoral hernias. The most common subtype of groin hernia in men and women is the indirect inguinal hernia.⁴

History

Evidence of surgical repair of inguinal hernias can be traced back to ancient civilizations of Egypt and Greece.⁵ Early management of inguinal hernias often involved a conservative approach with operative management reserved only for complications. Surgery often involved routine excision of the testicle, and wounds were closed with cauterization or left to granulate on their own. Considering these procedures were performed before the advent of the aseptic technique, it is safe to assume that mortality was quite high. For those that survived the operation, recurrence of the hernia was common.

From the late 1700s to the early 1800s, physicians including Hesselbach, Cooper, Camper, Scarpa, Richter, and Gimbernat identified vital components of the inguinal region, and their contributions are reflected in the current nomenclature. Improved understanding of the anatomy and pathophysiology of inguinal hernias, coupled with the development of aseptic technique, led surgeons such as Marcy, Kocher, and Lucas-Championnière to perform sac dissection, high ligation, and closure of the internal ring. Outcomes improved, but recurrence rates remained high with prolonged follow-up.

Based on a comprehensive understanding of inguinal anatomy, Bassini (1844–1924) transformed inguinal hernia repair into a successful venture with minimal morbidity. The success of the Bassini repair over its predecessors ushered in an era of tissue-based repairs. Modifications of the Bassini repair were manifest in the McVay and Shouldice repairs. All three of these techniques, as well as modern variations such as the Desarda operation, are currently practiced.⁶

In the early 1980s, Lichtenstein popularized the tension-free repair, supplanting tissue-based repairs with the widespread acceptance of prosthetic materials for inguinal floor reconstruction. This technique was superior to previous tissue-based repair in that mesh could restore the strength of the transversalis fascia, thereby avoiding tension in the defect closure. Superior results were reproducible regardless of hernia size and type, and they were achievable among expert and nonexpert hernia surgeons alike.⁷

With the advent of minimally invasive surgery, inguinal hernia repair underwent its most recent transformation. Laparoscopic inguinal hernia repair offers an alternative approach, minimizes postoperative pain, and improves recovery. Since the initial description by Ger, the laparoscopic method has become significantly more sophisticated. Refinements in approach and technique have led to the development of the intraperitoneal onlay mesh, the transabdominal preperitoneal (TAPP) repair, and the totally extraperitoneal (TEP) repair. Furthermore, an array of prosthetic materials has been introduced to minimize recurrence and improve quality of life. Irrespective of the approach, successful surgical treatment of inguinal hernias depends on a sound grasp of inguinal anatomy.

Anatomy

The inguinal canal is an approximately 4- to 6 cm-long cone-shaped region situated in the anterior portion of the pelvic basin (Fig. 37-1). The canal begins on the posterior abdominal wall, where the spermatic cord passes through the deep (internal) inguinal ring, a hiatus in the transversalis fascia. The canal concludes medially at the superficial (external) inguinal ring, the point at which the spermatic cord crosses a defect in the external oblique aponeurosis. The boundaries of the inguinal canal are comprised of the external oblique aponeurosis anteriorly, the internal oblique muscle laterally, the transversalis fascia and transversus abdominis muscle posteriorly, the internal oblique muscle superiorly, and the inguinal (Poupart’s) ligament inferiorly. The spermatic cord traverses the inguinal canal, and it contains three arteries, three veins, two nerves, the pampiniform venous plexus, and the vas deferens. It is enveloped in three layers of spermatic fascia.

Additional important structures surrounding the inguinal canal include the iliopubic tract, the lacunar ligament, Cooper’s ligament, and the conjoined tendon (Fig. 37-2). The iliopubic tract is an aponeurotic band that begins at the anterior superior iliac spine and inserts into Cooper’s ligament from above. It forms on the deep inferior margin of the transversus abdominis and transversalis fascia. The shelving edge of the inguinal ligament is a structure that connects the iliopubic tract to the inguinal ligament. The iliopubic tract helps form the inferior margin of the internal inguinal ring as it courses medially, where it continues as the anteromedial border of the femoral canal. The lacunar ligament, or ligament of Gimbernat, is the triangular fanning of the inguinal ligament as it joins the pubic tubercle. Cooper’s (pectineal) ligament is the lateral portion of the lacunar ligament that is fused to the periosteum of the pubic tubercle. The conjoined tendon is commonly described as the fusion of the inferior fibers of the internal oblique and transversus abdominis aponeurosis at the point where they insert on the pubic tubercle.

Inguinal hernias are generally classified as indirect, direct, and femoral based on the site of herniation relative to surrounding structures. Indirect hernias protrude lateral to the inferior epigastric vessels, through the deep inguinal ring. Direct hernias protrude medial to the inferior epigastric vessels, within Hesselbach’s triangle. The borders of the triangle are the inguinal ligament inferiorly, the lateral edge of rectus sheath medially, and the inferior epigastric vessels superolaterally. Femoral hernias protrude through the small and inflexible femoral ring. The borders of the femoral ring include the iliopubic tract and inguinal ligament anteriorly, Cooper’s ligament posteriorly, the lacunar ligament medially, and the femoral vein laterally. The Nyhus classification categorizes hernia defects by location, size, and type (Table 37-2).

The laparoscopic approach to hernia repair provides a posterior perspective to the peritoneal and preperitoneal spaces (Fig. 37-3). Intraperitoneal points of reference are the five peritoneal folds, bladder, inferior epigastric vessels, and psoas muscle (Fig. 37-4). Two potential spaces exist within the preperitoneum. Between the peritoneum and the posterior lamina of the transversalis fascia is Bogros’s (preperitoneal) space. This area contains preperitoneal fat and areolar tissue. The most medial aspect of the preperitoneal space, that which lies superior to the bladder, is known as the space of Retzius. The posterior perspective also allows visualization of the myopectineal orifice of Fruchaud, a relatively weak portion of the abdominal wall that is divided by the inguinal ligament (Fig. 37-5).

The vascular space is situated between the posterior and anterior laminae of the transversalis fascia, and it houses the inferior epigastric vessels. The inferior epigastric artery supplies the rectus abdominis. It is derived from the external iliac artery, and it anastomoses with the superior epigastric, a continuation of the internal thoracic artery. The epigastric veins course parallel to the arteries within the rectus sheath, posterior to the rectus muscles. Inspection of the internal inguinal ring will reveal the deep location of the inferior epigastric vessels.

Nerves of interest in the inguinal region are the ilioinguinal, iliohypogastric, genitofemoral, and lateral femoral cutaneous nerves (Figs. 37-6 and 37-7). The ilioinguinal and iliohypogastric nerves arise together from the first lumbar nerve (L1). The ilioinguinal nerve emerges from the lateral border of the psoas major and passes obliquely across the quadratus lumborum. At a point just medial to the anterior superior iliac spine, it pierces the transversus and internal oblique muscles to enter the inguinal canal and exits through the superficial inguinal ring. It supplies somatic sensation to the skin of the upper and medial thigh. In males, it also innervates the base of the penis and upper scrotum. In females, it innervates the mons pubis and labium majus. The iliohypogastric nerve arises from T12–L1. After it pierces the deep abdominal wall, it courses between the internal oblique and transversus abdominis, supplying both. It then divides into lateral and anterior cutaneous branches. A common variant is for the iliohypogastric and ilioinguinal nerves to exit around the superficial inguinal ring as a single entity. The genitofemoral nerve arises from L1–L2, courses along the retroperitoneum, and emerges on the anterior aspect of the psoas. It then divides into genital and femoral branches. The genital branch enters the inguinal canal lateral to the inferior epigastric vessels, and it courses ventral to the iliac vessels and iliopubic tract. In males, it travels through the superficial inguinal ring and supplies the ipsilateral scrotum and cremaster muscle. In females, it supplies the ipsilateral mons pubis and labium majus. The femoral branch courses along the femoral sheath, supplying the skin of the upper anterior thigh. The lateral femoral cutaneous nerve arises from L2–L3, emerges lateral to the psoas muscle at the level of L4, and crosses the iliacus muscle obliquely toward the anterior superior iliac spine. It then passes inferior to the inguinal ligament where it divides to supply the lateral thigh (Fig. 37-8).

The preperitoneal anatomy seen in laparoscopic hernia repair led to characterization of important anatomic areas of interest, known as the triangle of doom, the triangle of pain, and the circle of death (Fig. 37-9).⁸ The triangle of doom is bordered medially by the vas deferens and laterally by the vessels of the spermatic cord. The contents of the space include the external iliac vessels, deep circumflex iliac vein, femoral nerve, and genital branch of the genitofemoral nerve. The triangle of pain is a region bordered by the iliopubic tract and gonadal vessels, and it encompasses the lateral femoral cutaneous, femoral branch of the genitofemoral, and femoral nerves. The circle of death is a vascular continuation formed by the common iliac, internal iliac, obturator, inferior epigastric, and external iliac vessels.

Pathophysiology

Inguinal hernias may be congenital or acquired. Most adult inguinal hernias are considered acquired defects in the abdominal wall although collagen studies have demonstrated a heritable predisposition. A number of studies have attempted to delineate the precise causes of inguinal hernia formation; however, the best-characterized risk factor is weakness in the abdominal wall musculature (Table 37-3). Congenital hernias, which make up the majority of pediatric hernias, can be considered an impedance of normal development, rather than an acquired weakness. During the normal course of development, the testes descend from the intra-abdominal space into the scrotum in the third trimester. Their descent is preceded by the gubernaculum and a diverticulum of peritoneum, which protrudes through the inguinal canal and becomes the processus vaginalis. Between 36 and 40 weeks of gestation, the processus vaginalis closes and eliminates the peritoneal opening at the internal inguinal ring.⁹ Failure of the peritoneum to close results in a patent processus vaginalis (PPV), hence the high incidence of indirect inguinal hernias in preterm babies. Children with congenital indirect inguinal hernias will present with a PPV; however, a patent processus does not necessarily indicate an inguinal hernia (Fig. 37-10). In a study of nearly 600 adults undergoing general laparoscopy, bilateral inspection revealed that 12% had PPV. None of these patients had clinically significant symptoms of a groin hernia.¹⁰ In a group of 300 patients undergoing unilateral laparoscopic inguinal hernia repair, 12% were found to have a contralateral PPV, which was associated with a fourfold 5-year incidence of inguinal hernia.¹¹

The presence of a PPV likely predisposes a patient to the development of an inguinal hernia. This likelihood depends on the presence of other risk factors such as inherent tissue weakness, family history, and strenuous activity. Overall, there are limited data regarding the etiology of inguinal hernia development. Several studies have documented strenuous physical activity as a risk factor for acquired inguinal hernia.^12,13 Repeated physical exertion may increase intra-abdominal pressure; however, whether this process occurs in combination with a PPV or through age-related weakness of abdominal wall musculature is unknown. A case-controlled study of over 1400 male patients with inguinal hernia revealed that a positive family history was associated with an eightfold lifetime incidence of inguinal hernia. Chronic obstructive pulmonary disease also significantly increases the risk of direct inguinal hernias, as it is accompanied by repeated episodes of high intra-abdominal pressure.¹⁴ Several studies have suggested a protective effect of obesity. In a large, population-based prospective study of American individuals (First National Health and Nutrition Examination Survey), the risk of inguinal hernia development in obese men was only 50% that of normal weight males, whereas the risk in overweight males was 80% that of nonobese men. A possible explanation is the increased difficulty in detecting inguinal hernias in obese individuals.¹⁵

Epidemiologic studies have identified risk factors that may predispose to a hernia. Microscopic examination of skin of inguinal hernia patients demonstrated significantly decreased ratios of type I to type III collagen. Type III collagen does not contribute to wound tensile strength as significantly as type I collagen. Additional analyses revealed disaggregated collagen tracts with decreased collagen fiber density in hernia patients’ skin.¹⁶ Collagen disorders such as Ehlers-Danlos syndrome are also associated with an increased incidence of hernia formation (Table 37-4). Recent studies have found an association between concentrations of extracellular matrix elements and hernia formation.¹⁷ Although a significant amount of work remains to elucidate the biologic nature of hernias, current evidence suggests they have a multifactorial etiology with both environmental and hereditary influences.

History

Inguinal hernias present along a spectrum of scenarios. These range from incidental discovery to surgical emergencies such as incarceration and strangulation of the hernia sac contents. Patients who present with a symptomatic groin hernia will frequently report groin pain. Extrainguinal symptoms such as a change in bowel habits or urinary symptoms are less common. Inguinal hernias may compress adjacent nerves, leading to generalized pressure, localized sharp pain, and referred pain. Pressure or heaviness in the groin is a common complaint, especially at the conclusion of the day or following prolonged activity. Sharp pain tends to indicate an impinged nerve and may not be related to the extent of physical activity performed by the patient. Neurogenic pain may be referred to the scrotum, testicle, or inner thigh. Questions should be directed to elicit and characterize extrainguinal symptoms. A change in bowel habits or urinary symptoms may indicate a sliding hernia consisting of intestinal contents or involvement of the bladder within the hernia sac.

Important considerations of the patient’s history include the duration and timing of symptoms. Hernias will often increase in size and content over a protracted time. Much less commonly, a patient will present with a history of acute inguinal herniation following a strenuous activity. It is more likely that an asymptomatic inguinal hernia became evident once the patient experienced symptoms after an acute event. Questions should also be directed to characterize whether the hernia is reducible. Patients will often reduce the hernia by pushing the contents back into the abdomen, thereby providing temporary relief. As the defect size increases and more intra-abdominal contents fill the hernia sac, the hernia may become harder to reduce.

Physical Examination

Physical examination is essential to the diagnosis of inguinal hernia. Asymptomatic hernias are frequently diagnosed incidentally on physical examination or may be brought to the patient’s attention as an abnormal bulge. Ideally, the patient should be examined in a standing position to increase intra-abdominal pressure, with the groin and scrotum fully exposed. Inspection is performed first, with the goal of identifying an abnormal bulge along the groin or within the scrotum. If an obvious bulge is not detected, palpation is performed to confirm the presence of the hernia.

Palpation is performed by advancing the index finger through the scrotum toward the external inguinal ring (Fig. 37-11). This allows the inguinal canal to be explored. The patient is then asked to perform Valsalva’s maneuver to protrude the hernia contents. These maneuvers will reveal an abnormal bulge and allow the clinician to determine whether the hernia is reducible or not. Examination of the contralateral side affords the clinician the opportunity to compare the presence and extent of herniation between sides. This is especially useful in the case of a small hernia. In addition to inguinal hernia, a number of other diagnoses may be considered in the differential of a groin bulge (Table 37-5).

Certain techniques of the physical examination have classically been used to differentiate between direct and indirect hernias. The inguinal occlusion test entails the examiner blocking the internal inguinal ring with a finger as the patient is instructed to cough. A controlled impulse suggests an indirect hernia, while persistent herniation suggests a direct hernia. Transmission of the cough impulse to the tip of the finger implies an indirect hernia, while an impulse palpated on the dorsum of the finger implies a direct hernia. When results of physical examination are compared against operative findings, there is a probability somewhat higher than chance (i.e., 50%) of correctly diagnosing the type of hernia.^18,19 Accordingly, these tests should be used to detect hernias, but not to diagnose hernia types.

External groin anatomy is difficult to assess in obese patients, making the physical diagnosis of inguinal hernia challenging. A further challenge to the physical examination is the identification of a femoral hernia. Femoral hernias should be palpable below the inguinal ligament, lateral to the pubic tubercle. In obese patients, a femoral hernia may be missed or misdiagnosed as a hernia of the inguinal canal. In contrast, a prominent inguinal fat pad in a thin patient, otherwise known as a femoral pseudohernia, may prompt an erroneous diagnosis of femoral hernia.

Imaging

In the case of an ambiguous diagnosis, radiologic investigations may be used as an adjunct to history and physical examination. Imaging in obvious cases is unnecessary and costly. The most common radiologic modalities include ultrasonography (US), computed tomography (CT), and magnetic resonance imaging (MRI). Each technique has certain advantages over physical examination alone; however, each modality is associated with potential limitations.

US is the least invasive technique and does not impart any radiation to the patient. Anatomic structures can be more easily identified by the presence of bony landmarks; however, because there are few bones in the inguinal canal, other structures such as the inferior epigastric vessels are used to define groin anatomy. Positive intra-abdominal pressure is used to elicit the herniation of abdominal contents. Movement of these contents through the canal is essential to making the diagnosis with US, and lack of this movement may lead to a false-negative result. A recent meta-analysis demonstrated that US detects inguinal hernia with a sensitivity of 86% and specificity of 77%.²⁰ In thin patients, normal movement of the spermatic cord and posterior abdominal wall against the anterior abdominal wall may lead to false-positive diagnoses of hernia.²¹

CT and MRI provide static images that are able to delineate groin anatomy, to detect groin hernias, and to exclude potentially confounding diagnoses (Fig. 37-12). A meta-analysis determined that standard CT detects inguinal hernia with a sensitivity of 80% and specificity of 65%. Although direct herniography has a higher sensitivity and specificity than CT, its invasiveness and limited availability restrict its routine use.²⁰ As CT imaging increases in resolution, its sensitivity in detecting inguinal hernia is expected to expand; however, this has yet to be clinically confirmed by surgical correlation.²²

When used to diagnose inguinal hernia, MRI is frequently reserved for cases where physical examination detects a groin bulge, but where US is inconclusive. In a 1999 study of 41 patients with clinical findings of inguinal hernia, laparoscopy revealed that MRI was an effective diagnostic test, with a sensitivity of 95% and specificity of 96%.²³ MRI has become more sophisticated since 1999; however, its high cost and limited access remain obstacles to more routine use.

Surgical repair is the definitive treatment of inguinal hernias; however, operation is not necessary in a subset of patients. When the patient’s medical condition confers an unacceptable level of operative risk, elective surgery should be deferred until the condition resolves, and operations reserved for life-threatening emergencies. Although the natural history of untreated inguinal hernias is poorly defined, the rates of incarceration and strangulation are low in the asymptomatic population. As a result, nonoperative management is an appropriate consideration in minimally symptomatic patients. Prospective studies and meta-analyses have demonstrated no difference in intent-to-treat outcomes, quality of life, or cost-effectiveness between nonoperative management and elective repair among healthy inguinal hernia patients.^24,25 A 2012 systematic review found that 72% of asymptomatic inguinal hernia patients developed symptoms (mostly pain) and had surgical repair within 7.5 years of diagnosis.²⁶ Nevertheless, the complication rates of immediate and delayed elective tension-free repair are equivalent.^25,27 A nonoperative strategy is safe for minimally symptomatic inguinal hernia patients, and it does not increase the risk of developing hernia complications.

Nonoperative inguinal hernia treatment targets pain, pressure, and protrusion of abdominal contents in the symptomatic patient population. The recumbent position aids in hernia reduction via the effects of gravity and a relaxed abdominal wall. Trusses externally confine hernias to a reduced state and intermittently relieve symptoms in up to 65% of patients; however, they do not prevent complications, and they may be associated with an increased rate of incarceration.²⁸ The risks of incarceration and strangulation appear to decrease over the first year, likely because gradual enlargement of the abdominal wall defect facilitates spontaneous reduction of hernia contents. The sheer volume of protruding tissue in an inguinal hernia does not necessarily signify severe morbidity.

Femoral and symptomatic inguinal hernias carry higher complication risks, and so surgical repair is performed earlier for these patients. Irrespective of symptoms, one study found the 3-month and 2-year cumulative incidences of strangulation were 2.8% and 4.5%, respectively, for inguinal hernias and 22% and 45%, respectively, for femoral hernias.²⁹ Data from the Swedish Hernia Registry demonstrate that emergent operation is associated with a sevenfold increase in all-cause mortality over that of elective surgery among 107,838 groin hernia repairs.³⁰ For this reason, it is recommended that femoral hernias and symptomatic inguinal hernias be electively repaired, when possible.

The administration of preoperative prophylactic antibiotics in elective inguinal hernia repair remains controversial. A systematic review of 7843 elective open hernia repairs from the Cochrane Database in 2012 revealed an overall decrease in infection rates (odds ratio [OR] 0.64, confidence interval [CI] 0.50–0.82) when prophylactic antibiotics are administered; however, the absolute risk reduction was not sufficient to justify universal recommendations for or against the practice. Overall wound infection rates are higher than those expected for clean operations, and there was a significant reduction in the rate of wound infection among patients undergoing repair with a prosthetic mesh.^31,32 Although there is no universal guideline regarding the administration of prophylactic antibiotics for open elective hernia repair, it is our experience that meticulous perioperative protocol and surgical technique are more reliable countermeasures to prevent wound infection than antibiotics. Nevertheless, data trends and quality improvement measures have resulted in routine administration of prophylactic perioperative antibiotics in inguinal hernia repairs.

Incarceration occurs when hernia contents fail to reduce; however, a minimally symptomatic, chronically incarcerated hernia may also be treated nonoperatively. Taxis should be attempted for incarcerated hernias without sequelae of strangulation, and the option of surgical repair should be discussed prior to the maneuver. To perform taxis, analgesics and light sedatives are administered, and the patient is placed in the Trendelenburg position. The hernia sac is elongated with both hands, and the contents are compressed in a milking fashion to ease their reduction into the abdomen.

The indication for emergent inguinal hernia repair is impending compromise of intestinal contents. As such, strangulation of hernia contents is a surgical emergency. Clinical signs that indicate strangulation include fever, leukocytosis, and hemodynamic instability. The hernia bulge is usually warm and tender, and the overlying skin may be erythematous or discolored. Symptoms of bowel obstruction in patients with sliding or incarcerated inguinal hernias may also indicate strangulation. Taxis should not be performed when strangulation is suspected, as reduction of potentially gangrenous tissue into the abdomen may result in an intra-abdominal catastrophe. Preoperatively, the patient should receive fluid resuscitation, nasogastric decompression, and prophylactic intravenous antibiotics.

Open Approach

Open inguinal hernia repairs are subdivided into techniques that employ prostheses to create a tension-free repair and those that reconstruct the inguinal floor using native tissue. Tissue repairs are indicated when the use of prosthetic material is contraindicated, (contamination or strangulation).

The option to administer locoregional anesthesia is an advantage of the open approach. Common anesthetic agents include lidocaine or the longer-acting bupivacaine, both with the option of adding epinephrine. In advance of the initial incision, a field block or ilioinguinal nerve block may be employed. A regional block is an option for patients who cannot tolerate general anesthesia, and it exerts a broader effect than local anesthesia alone.

Exposure of the anterior inguinal region is common to the open approaches. An oblique or horizontal incision is performed over the groin (Fig. 37-13). The incision begins two fingerbreadths inferior and medial to the anterior superior iliac spine. It is then extended medially for approximately 6 to 8 cm.The subcutaneous tissue is dissected using electrocautery. Scarpa’s fascia is divided to expose the external oblique aponeurosis. A small incision is made in the external oblique aponeurosis parallel to the direction of the muscle fibers. Metzenbaum scissors are introduced and spread beneath the fibers to separate adhesions to the underlying ilioinguinal nerve. The scissors are then used to incise the aponeurosis superior to the inguinal ligament, splitting the external inguinal ring.

The flaps of the external oblique aponeurosis are elevated with Hemostat clamps. The interior oblique fibers are dissected bluntly from the overlying external oblique flaps. Dissection of the inferior flap reveals the shelving edge of the inguinal ligament. The iliohypogastric and ilioinguinal nerves are identified and preserved. Effort should be made to avoid removing nerves from their natural bed and disrupting the protective investing fascia. The pubic tubercle is identified and the cord structures are atraumatically dissected off of the pubis, encircled, and elevated with a Penrose drain. The cord is elevated 2 cm over the pubic symphysis in an avascular plane, and cremasteric fibers are preserved to avoid injuring cord structures (Fig. 37-14).

An indirect hernia sac will generally be found on the anterolateral surface of the spermatic cord after division of the cremasteric muscle in the direction of its fibers. The genital nerve is visualized along the inferolateral surface of the cord adjacent to the external spermatic vein. The floor of the inguinal canal is fully assessed for direct hernias. If a hernia is not visualized upon entry into the inguinal canal, the preperitoneal space should be explored for a femoral hernia. In addition to sac identification, the vas deferens and vessels of the spermatic cord must be identified to allow dissection of the sac from the cord. At the leading edge of the sac, the two layers of peritoneum will fold upon themselves and reveal a white edge, which may help in the identification of the sac. The sac can then be grasped with a tissue forceps and bluntly dissected from the cord. The dissection is carried proximally toward the deep inguinal ring.

In cases where the viability of sac contents is in question, the sac should be incised, and hernia contents should be evaluated for signs of ischemia. The defect should be enlarged to augment blood flow to the sac contents. Viable contents may be reduced into the peritoneal cavity, while nonviable contents should be resected, and synthetic prostheses should be avoided in the repair. In elective cases, the sac may be amputated at the internal inguinal ring or inverted into the preperitoneum. Both methods are effective; however, patients undergoing sac excision had significantly increased postoperative pain in a prospective trial.³³ Dissection of a densely adherent sac may result in injury to cord structures and should be avoided; however, sac ligation at the internal inguinal ring is necessary in these cases. A hernia sac that extends into the scrotum may require division within the inguinal canal, as extensive dissection and reduction risks injury to the pampiniform plexus, resulting in testicular atrophy and orchitis.

At this point, the inguinal canal is reconstructed, either with native tissue or with prostheses. The following sections describe the most commonly performed types of tissue-based and prosthetic-based reconstructions.

Tissue Repairs

Tissue-based herniorrhaphy is a suitable alternative when prosthetic materials cannot be used safely. Indications for tissue repairs include operative field contamination, emergency surgery, and when the viability of hernia contents is uncertain. General surgeons should understand inguinal anatomy and possess the expertise and ability to perform an effective tissue-based repair.

Bassini Repair

The Bassini repair was an historic advancement in operative technique. Its current use is limited, as modern techniques reduce recurrence. The original repair includes dissection of the spermatic cord, dissection of the hernia sac with high ligation, and extensive reconstruction of the floor of the inguinal canal (Fig. 37-15). After exposing the inguinal floor, the transversalis fascia is incised from the pubic tubercle to the internal inguinal ring. Preperitoneal fat is bluntly dissected from the upper margin of the posterior side of the transversalis fascia to permit adequate tissue mobilization. A triple-layer repair is then performed. The internal oblique, transversus abdominis, and transversalis fascia are fixed to the shelving edge of the inguinal ligament and pubic periosteum with interrupted sutures. The lateral aspect of the repair reinforces the medial border of the internal inguinal ring.

Shouldice Repair

The Shouldice repair recapitulates principles of the Bassini repair, and its distribution of tension over several tissue layers results in lower recurrence rates (Fig. 37-16). During dissection of the cord, the genital branch of the genitofemoral nerve is routinely divided, resulting in ipsilateral loss of sensation to the scrotum in men or the mons pubis and labium majus in women. With the posterior inguinal floor exposed, an incision in the transversalis fascia is made between the pubic tubercle and internal ring. Care is taken to avoid injury to preperitoneal structures, which are bluntly dissected to mobilize the upper and lower fascial flaps. At the pubic tubercle, the iliopubic tract is sutured to the lateral edge of the rectus sheath using a synthetic, nonabsorbable, monofilament suture. This continuous suture progresses laterally, approximating the edge of the inferior transversalis flap to the posterior aspect of the superior flap. At the internal inguinal ring, the suture continues back in the medial direction, approximating the edge of the superior transversalis fascia flap to the shelving edge of the inguinal ligament. At the pubic tubercle, this suture is tied to the tail of the original stitch. The next suture begins at the internal inguinal ring, and it continues medially, apposing the aponeuroses of the internal oblique and transversus abdominis to the external oblique aponeurotic fibers. At the pubic tubercle, the suture doubles back through the same structures laterally toward the tightened internal ring.

McVay Repair

The McVay repair addresses both inguinal and femoral ring defects. This technique is indicated for femoral hernias and in cases where the use of prosthetic material is contraindicated (Fig. 37-17). Once the spermatic cord has been isolated, an incision in the transversalis fascia permits entry into the preperitoneal space. The upper flap is mobilized by gentle blunt dissection of underlying tissue. Cooper’s ligament is bluntly dissected to expose its surface. A 2- to 4-cm relaxing incision is made in the anterior rectus sheath vertically from the pubic tubercle. This incision is essential to reduce tension on the repair; however, it may result in increased postoperative pain and higher risk of ventral abdominal herniation. Using either interrupted or continuous suture, the superior transversalis flap is then fastened to Cooper’s ligament, and the repair is continued laterally along Cooper’s ligament to occlude the femoral ring. Lateral to the femoral ring, a transition stitch is placed, affixing the transversalis fascia to the inguinal ligament. The transversalis is then sutured to the inguinal ligament laterally to the internal ring.

Prosthetic Repairs

The popularization of tension-free prosthetic mesh repairs signified a paradigm shift in the surgical concept of inguinal hernia pathophysiology. Mesh-based hernioplasty is the most commonly performed general surgical procedure, owing to the technique’s efficacy and improved outcomes. The techniques of the most commonly performed prosthetic repairs are presented in this section.

Lichtenstein Tension-Free Repair

The Lichtenstein technique expands the domain of the inguinal canal by reinforcing the inguinal floor with a prosthetic mesh, thereby minimizing tension in the repair (Fig. 37-18). Initial exposure and mobilization of cord structures is identical to other open approaches. The inguinal canal is dissected to expose the shelving edge of the inguinal ligament, the pubic tubercle, and sufficient area for mesh. The mesh is a 7 × 15 cm rectangle with a rounded medial edge, and it must be large enough to extend 2 to 3 cm superior to Hesselbach’s triangle. The lateral portion of the mesh is split such that the superior tail comprises two thirds of its width, and the inferior tail comprises the remaining one third. The medial edge of the mesh is affixed to the anterior rectus sheath such that it overlaps the pubic tubercle by 1.5 to 2 cm. This refinement to the original Lichtenstein technique minimizes medial recurrence.³⁴

For fixation of the inferior margin of the mesh, a permanent, synthetic, monofilament suture is used, taking care to avoid placing sutures directly into the periosteum of the pubic tubercle. Fixation is continued along the shelving edge of the inguinal ligament from medial to lateral, ending at the internal ring. The upper tail of the mesh is then fixed to the internal oblique aponeurosis and the medial edge to the rectus sheath using a synthetic, absorbable suture.

In the case of a femoral hernia, a triangular extension of the inferior aspect of the mesh is sutured to Cooper’s ligament medially and to the inguinal ligament laterally. The lateral tails of the mesh are tailored to fit snugly around the cord at the internal ring, but not too tight to strangulate it. The tails are then sutured to the inguinal ligament with an interrupted stitch and placed beneath the external oblique aponeurosis.

Plug and Patch Technique

A modification of the Lichtenstein repair, the plug and patch technique was developed by Gilbert and later popularized by Rutkow and Robbins.³⁵ Prior to placing the prosthetic mesh patch over the inguinal floor, a three-dimensional prosthetic plug is placed in the space previously occupied by the hernia sac (Fig. 37-19). In the case of an indirect hernia, the plug is placed alongside the spermatic cord through the internal ring. Prosthetic plugs of various sizes are available, and one of appropriate size is fixed to the margins of the internal ring with interrupted sutures.³⁶ For direct hernias, the sac is reduced, and the plug is sutured to Cooper’s ligament, the inguinal ligament, and the internal oblique aponeurosis.

Prolene Hernia System

The Prolene Hernia System (PHS) repair provides reinforcement to the anterior and posterior aspects of the abdominal wall. Exposure of the inguinal canal is identical to that of other open approaches. With an indirect hernia, the sac is dissected from the spermatic cord, and the preperitoneal space is bluntly dissected through the internal ring. With a direct hernia, the transversalis fascia is opened at the defect, and the preperitoneal space is bluntly dissected to create space for the mesh. The mesh has an underlay flap and an onlay flap, joined by a short cylindrical connector (Fig. 37-20). The underlay portion of the mesh is then placed through the hernia defect into the preperitoneal space. The advantage of the preperitoneal mesh position is that increased intra-abdominal pressure pushes the mesh into closer apposition to the abdominal wall. The overlay flap reinforces the inguinal floor similar to a tension-free repair. The spermatic cord is placed through a slit in the onlay portion of the mesh. Three to four circumferential interrupted sutures anchor the anterior layer of the mesh to the inguinal canal floor.

Wound Closure

Once the reconstruction of the inguinal canal is complete, the cord contents are returned to their anatomic position. The external oblique aponeurosis is then reapproximated continuously from medial to lateral using an absorbable suture. The external ring should be reconstructed in close apposition to the spermatic cord to avoid the appearance of recurrence on future examination. Scarpa’s fascia and skin are appropriately closed.

Giant Prosthetic Reinforcement of the Visceral Sac

In giant prosthetic reinforcement of the visceral sac, also known as the Stoppa repair, a broad prosthetic mesh is placed in the preperitoneal space from an anterior approach. In unilateral repair, an 8- to 10-cm Pfannenstiel or low transverse incision is made above the internal inguinal ring. The lateral aspect of the rectus sheath and the oblique muscles are divided along the length of the incision. The transversalis is incised, and the preperitoneal space is dissected widely (Fig. 37-21). The preperitoneal dissection is carried medially to expose Cooper’s ligament and laterally over the iliopubic tract to the anterior superior iliac spine. If bilateral hernias are present, a lower midline incision allows for access and the preperitoneal dissection spans the entire area between both anterior superior iliac spines and both inguinal canals. For direct defects, the transversalis fascia may be sutured to Cooper’s ligament to obliterate the sac’s laxity. Indirect hernias require directed dissection from the internal ring. Large or densely adherent indirect hernia sacs are dissected from the cord at the internal ring and ligated, and the peritoneum is closed.

The mesh should be large enough to cover the area from the midline to 1 cm medial to the anterior superior iliac spine and from the umbilicus to the pubic symphysis. The middle portion and lower corners of the mesh are clamped. The mesh is placed flat along the inferior margin of the preperitoneal space (Fig. 37-22). The medial clamp is directed into the space of Retzius, the middle clamp is placed over the pubic ramus and iliac vessels, and the lateral clamp is placed into the iliac fossa cover the spermatic cord. Splitting the mesh to accommodate the cord may predispose to hernia recurrence. Alternatively, the mesh may be fixed with interrupted sutures to the anterior abdominal wall; however, care must be taken to avoid injuring the lateral femoral cutaneous nerve and the inferior epigastric vessels. For bilateral hernias, a single large mesh is placed into the preperitoneal space using up to eight clamps along its inferior edge. The transversalis is reapproximated and the wound is closed.

Laparoscopic Approach

Laparoscopic inguinal hernia repairs reinforce the abdominal wall via a posterior approach. Principal laparoscopic methods include the transabdominal preperitoneal (TAPP) repair, the totally extraperitoneal (TEP) repair, and the less commonly performed intraperitoneal onlay mesh (IPOM) repair.

Although laparoscopic repairs in experienced hands are relatively expedient, they necessitate the administration of general anesthesia and its inherent risks. Any patient with a contraindication to the use of general anesthesia should not undergo laparoscopic hernia repair. Occasionally, general anesthesia induction may result in reduction of an incarcerated or strangulated inguinal hernia. If the surgeon suspects this might have occurred, the abdomen should be explored for nonviable tissue either via laparoscopy or upon conversion to an open laparotomy.

The indications for laparoscopic inguinal hernia repair are similar to those for open repair. Most surgeons would agree that the laparoscopic approach to bilateral or recurrent inguinal hernias is superior to the open approach.³⁷ Concurrent inguinal hernia repair should be considered if a hernia patient is scheduled to undergo another clean laparoscopic procedure, such as prostatectomy.^38,39 International Endohernia Society (IEHS) guidelines offer a Grade A recommendation that TEP and TAPP are preferred alternatives to Lichtenstein repair for recurrent hernias after open anterior repair.⁴⁰ The possibility of bilateral repair should be discussed with all patients undergoing laparoscopic inguinal hernia surgery.

The operating room configuration is identical for TAPP, TEP, and IPOM procedures. The patient is placed in the Trendelenburg position, and video screens are placed at the foot of the bed. The surgeon stands contralateral to the hernia, and the assistant stands opposite the surgeon. The patient’s arms are tucked to the sides. Fig. 37-23 demonstrates a typical operating room setup for laparoscopic inguinal hernia repair. The following sections outline the most commonly performed laparoscopic inguinal hernia repair techniques.

Transabdominal Preperitoneal Procedure

The transabdominal approach confers the advantage of an intraperitoneal perspective, which is useful for bilateral hernias, large hernia defects, and scarring from previous lower abdominal surgery. The abdominal cavity is accessed using a dissecting trocar or open Hasson technique. Pneumoperitoneum is instilled to a level of 15 mmHg. Two 5-mm trocars are placed lateral and slightly inferior to the umbilical trocar, avoiding injury to the inferior epigastric vessels (Fig. 37-24). The patient is then placed in the Trendelenburg position, and the pelvis is inspected.

The bladder, median and medial umbilical ligaments, external iliac, and inferior epigastric vessels are visualized. An incision is made in the peritoneum at the medial umbilical ligament 3 to 4 cm superior to the hernia defect, and it is carried laterally to the anterior superior iliac spine. For bilateral inguinal hernia repair, bilateral peritoneal incisions are advisable, leaving a midline bridge of tissue to avoid injuring a potential patent urachus. The inferior edge of incised peritoneum is retracted, and the preperitoneum is dissected to expose the spermatic cord. If a direct hernia is encountered, the sac is inverted and fixed to Cooper’s ligament to prevent development of hematoma or seroma. An indirect hernia sac will usually protrude anterior to the spermatic cord. In this case, the sac is grasped and elevated superiorly from the cord and the space below is developed bluntly to allow for mesh placement. The sac is dissected from its adhesions, and the cord is skeletonized.

The mesh usually measures 10 × 15 cm to completely cover the myopectineal orifice (Fig. 37-25). It is rolled lengthwise and placed through the 12-mm trocar. It is unrolled in the preperitoneal space and secured medially to Cooper’s ligament using a spiral tacker. During this fixation, the surgeon palpates the end of the tacker from the abdominal surface to ensure its proper angle and to stabilize the pelvis. The mesh is then pulled taut and fixed lateral to the anterior superior iliac spine. Tacks are placed above the iliopubic tract to avoid injury to the lateral cutaneous nerve of the thigh and the femoral branch of the genitofemoral nerve. The peritoneal edges are reapproximated using tacks or intracorporeal sutures as the mesh is stabilized. The peritoneum should be closed completely to avoid contact between the mesh and the intestine. The abdomen is desufflated and the trocars are removed. The fascial defect of the 12-mm port and the skin incisions are appropriately closed.

Totally Extraperitoneal Procedure

The advantage of the TEP repair is the access to the preperitoneal space without intraperitoneal infiltration. Consequently, this approach minimizes the risk of injury to intra-abdominal organs and port site herniation through an iatrogenic defect in the abdominal wall. As with TAPP, TEP is indicated for repair of bilateral inguinal hernias or for unilateral hernias when scarring makes the anterior approach challenging.

A small horizontal incision is made inferior to the umbilicus. Subcutaneous tissue is dissected to the level of the anterior rectus sheath, which is then incised lateral to the linea alba. The rectus muscle is retracted superolaterally, and a dissecting balloon is advanced through the incision toward the pubic symphysis. Under direct visualization with a 30° laparoscope, the balloon is inflated slowly to bluntly dissect the preperitoneal space (Fig. 37-26). The dissecting balloon is replaced with a 12-mm balloon trocar, and pneumopreperitoneum is achieved by insufflation to 15 mmHg. A 5-mm trocar is placed suprapubically in the midline, and another is placed inferior to the insufflation port (see Fig. 37-24). The patient is placed in the Trendelenburg position, and the operation proceeds in an identical fashion to TAPP. No modifications are necessary to repair bilateral inguinal hernias with the TEP approach.Any peritoneal rents should be repaired prior to desufflation to prevent mesh from contacting intraperitoneal structures. Following mesh placement, the preperitoneal space is desufflated slowly under direct vision to ensure proper mesh positioning. Trocars are removed, and the anterior rectus sheath is closed with an interrupted suture.

Intraperitoneal Onlay Mesh Procedure

In contrast to TAPP and TEP, the IPOM procedure permits the posterior approach without preperitoneal dissection. It is an attractive procedure in cases where the anterior approach is unfeasible, in recurrent hernias that are refractory to other approaches, or where extensive preperitoneal scarring would make TEP or TAPP challenging. Port placement and inguinal hernia identification are identical to TAPP. Hernia sac contents are reduced; however, the sac itself is not inverted from the preperitoneal space. Instead, mesh is placed directly over the defect and fixed in place with sutures or spiral tacks. Because these anchors are placed through the peritoneum without preperitoneal inspection, the lateral cutaneous nerve of the thigh and the genitofemoral nerve are especially prone to injury. Furthermore, intraperitoneal mesh migration is a documented phenomenon that can lead to postoperative morbidity, recurrence, and reoperation.

Prosthesis Considerations

The success of prosthetic repairs has generated considerable debate about the desirable physical attributes of mesh and their fixation. An ideal mesh should be easy to handle, flexible, strong, immunologically inert, contraction-resistant, infection-resistant, and inexpensive to manufacture.⁴¹ The following section reviews the most common types of mesh and fixatives currently available.

Synthetic Mesh Material

Polypropylene and polyester are the most common synthetic prosthetic materials used in hernia repair. These materials are permanent and hydrophobic, and they promote a local inflammatory response that results in cellular infiltration and scarring with slight contraction in size. Other synthetic mesh materials are under investigation with the goals of minimizing postoperative pain and preventing infection or recurrence. In selecting mesh material, considerations include mesh absorbability, thickness, weight, porosity, and strength.

Variations in the fiber diameter and fiber count of mesh materials categorize them as heavyweight or lightweight in density. Commonly used lightweight mesh materials include β-d-glucan, titanium-coated polypropylene, and polypropylene-poliglecaprone. These materials have greater elasticity and less theoretical surface area contact with surrounding tissues than their heavyweight counterparts.⁴² Accordingly, they are hypothesized to reduce scarring and chronic pain with equivalent recurrence rates. The use of lightweight mesh in TEP and TAPP repairs is associated with fewer 3-month cumulative mesh-related complications.⁴⁰ A 2012 meta-analysis of 2310 patients undergoing open or laparoscopic hernia repairs found a lower incidence of chronic pain (relative risk [RR] 0.61, CI 0.50–0.74) following use of lightweight mesh versus heavyweight mesh, and no significant difference in rates of recurrence.⁴³ When available, lightweight mesh should be considered for all prosthetic repairs to minimize postoperative chronic pain.

A disadvantage of currently available commercial prostheses is their high cost. In settings where resources are limited, prosthetic repairs are performed using alternative materials. Polypropylene and polyethylene mosquito nets are inexpensive and ubiquitous in sub-Saharan Africa and India, and they have similar mechanical properties to commercially available hernioplasty meshes. Meta-analysis of 577 hernioplasties performed using sterilized mosquito nets demonstrated similar rates of short-term mesh-related complications (6.1%) and recurrence (0.17%) to those using commercial meshes.⁴⁴ Furthermore, the disability-adjusted life-years (DALYs) prevented by inguinal hernia repair signify a comparable impact to that of vaccination in sub-Saharan Africa.^45,46 Expensive prostheses are not necessarily needed for hernia surgery, either in resource-limited or in resource-abundant settings, and the anticipated benefits should be evaluated with consideration of increased costs.

Biologic Mesh

Although indications for the use of biologic prostheses have not been absolutely defined, they are commonly reserved for contaminated cases or when domain expansion is necessary in the face of high infection risk. There are numerous biologic materials available with differing properties, but in general, they have lower tensile strength and subsequent higher rates of rupture than synthetic prostheses.⁴⁷ They also have varying degrees of tensile strength and tissue biocompatibility between them. In ventral hernia repairs, xenograft material was associated with a lower rate of recurrence than allograft material.⁴⁸ A review of biologic materials concluded that cross-linked graft materials are more durable and less prone to failure than non–cross-linked grafts.⁴⁹ Nevertheless, their diminished ability to remodel adversely affects rates of infection and incorporation. While new prosthetic materials continue to be developed, no single biologic warrants routine use. These materials will continue to evolve, and they remain an important tool for challenging cases when used judiciously.

Fixation Technique

Independent of prosthesis material, the method of its fixation remains disputed. Suturing, stapling, and tacking prostheses entail tissue perforation, which may cause inflammation, neurovascular injury, and chronic pain development. Conversely, improper prosthesis fixation may result in mesh migration, repair failure, meshoma pain, and hernia recurrence. Mesh may be fixed with fibrin-derived glue, and self-gripping mesh has been developed to minimize trauma to surrounding tissues and to reduce the risk for entrapment neuropathy. For hernias repaired via a strictly preperitoneal approach, prosthesis fixation may not be necessary at all.

Fibrin glue fixation is a successful alternative to tack fixation in hernia repair with a synthetic prosthesis. Recent studies comparing fibrin glue fixation and suture fixation in open hernia repair show superior rates of chronic pain with both Lichtenstein and plug and patch techniques.^50,51 Meta-analyses of laparoscopic hernia repair determined the incidence of chronic postoperative pain after tacker fixation was significantly higher than after fibrin glue fixation, with one showing an RR of 4.64 (CI 1.9–11.7). Rates of other postoperative complications and recurrence were similar between both fixation methods.^52,53 Glue fixation is a promising technical refinement; however, its questionable efficacy in larger hernias, long-term outcomes, and cost remain considerations.

In TEP repairs, fixation of mesh may not be compulsory. A prospective randomized trial comparing fixation and no fixation in TEP repairs found a significant increase in new pain and equivalent recurrence rates in the fixation group several months after repair.⁵⁴ A 2012 meta-analysis comparing laparoscopic tacker mesh fixation to no mesh fixation found no statistically significant differences in operative duration, pain, mesh-related complications, recurrence, or length of stay between the two methods.⁵⁵ Studies of three-dimensional, ergonomically contoured mesh without fixation, as well as self-gripping meshes, have yielded similar results.⁵⁶ In the preperitoneal approach, the re-approximation of surrounding tissues and physiologic intra-abdominal pressure hypothetically prevent mesh migration. Due to higher theoretical risk of mesh migration, repair without fixation is not recommended for anterior or transperitoneal approaches.

As with other clean operations, the most common complications of inguinal hernia repair include bleeding, seroma, wound infection, urinary retention, ileus, and injury to adjacent structures (Table 37-6). Complications specific to herniorrhaphy and hernioplasty include hernia recurrence, chronic inguinal and pubic pain, and injury to the spermatic cord or testis. The incidence, prevention, and treatment of these complications are discussed in the ensuing section.

Hernia Recurrence

When a patient develops pain, bulging, or a mass at the site of an inguinal hernia repair, clinical entities such as seroma, persistent cord lipoma, and hernia recurrence should be considered. Common medical issues associated with recurrence include malnutrition, immunosuppression, diabetes, steroid use, and smoking. Technical causes of recurrence include improper mesh size, tissue ischemia, infection, and tension in the reconstruction. A focused physical examination should be performed. As with primary hernias, US, CT, or MRI can elucidate ambiguous physical findings. When a recurrent hernia is discovered and warrants re-operation, an approach through a virgin plane facilitates its dissection and exposure. Extensive dissection of the scarred field and mesh may result in injury to cord structures, viscera, large blood vessels, and nerves. After an initial anterior approach, the posterior laparoscopic approach will usually be easier and more effective than another anterior dissection. Conversely, failed preperitoneal repairs should be approached using an open anterior repair.

Pain

Pain after inguinal hernia repair is classified into acute or chronic manifestations of three mechanisms: nociceptive (somatic), neuropathic, and visceral pain. Nociceptive pain is the most common of the three. Because it is usually a result of ligamentous or muscular trauma and inflammation, nociceptive pain is reproduced with abdominal muscle contraction. Treatment consists of rest, nonsteroidal anti-inflammatory drugs (NSAIDs), and reassurance, as it resolves spontaneously in most cases. Neuropathic pain occurs as a result of direct nerve damage or entrapment. It may present early or late, and it manifests as a localized, sharp, burning or tearing sensation. It may respond to pharmacologic therapy and to local steroid or anesthetic injections when indicated. Visceral pain refers to pain conveyed through afferent autonomic pain fibers. It is usually poorly localized and may occur during ejaculation as a result of sympathetic plexus injury.

Chronic postoperative pain remains an important measure of clinical outcome that has been reported in as many as 63% of inguinal hernia repair cases.^57,58,59 Despite the significant anatomic variation in the three inguinal nerves, literature reviews suggest identification of all three nerves is possible in 70% to 90% of cases.⁶⁰ Meticulous nerve identification may prevent injury that results in debilitating chronic postoperative pain syndromes. Notwithstanding, moderate-to-severe pain adversely affects physical activity, social interactions, healthcare utilization, employment, and productivity in 6% to 8% of patients.^{58,59,61,62,63,64} Pain in this subset of patients comprises a tremendous individual and societal burden.

Post-herniorrhaphy inguinodynia is a debilitating chronic complication caused by a combination of nociceptive, neuropathic, and visceral elements. Its incidence is independent of the method of hernia repair; however, the original operative technique determines options for intervention and remedial surgery.⁶² Treatment is based on repair technique, subsequent re-operations, pain character, and the presence of recurrence, meshoma, and fixation material. Selective ilioinguinal, iliohypogastric, and genitofemoral neurolysis or neurectomy, removal of mesh and fixation material, and revision of the repair are common options for treatment. Nevertheless, anatomic variation and cross-innervation of the inguinal nerves in the retroperitoneum and inguinal canal make selective neurectomy less reliable.^{65,66,67,68,69} When inguinodynia is refractory to pharmacologic and interventional measures, triple neurectomy with removal of meshoma is arguably the most effective option for the majority of patients.^{64,67,68,69,70,71,72,73,74} Refractory inguinodynia with concurrent orchialgia also requires resection of the paravasal nerves.⁷⁴

Other chronic pain syndromes include local nerve entrapment, meralgia paresthetica, and osteitis pubis. At greatest risk of entrapment are the ilioinguinal and iliohypogastric nerves in anterior repairs and the genitofemoral and lateral femoral cutaneous nerves in laparoscopic repairs. Clinical manifestations of nerve entrapment mimic acute neuropathic pain, and they occur with a dermatomal distribution. Injury to the lateral femoral cutaneous nerve results in meralgia paresthetica, a condition characterized by persistent paresthesias of the lateral thigh. Initial treatment of nerve entrapment consists of rest, ice, NSAIDs, physical therapy, and possible local corticosteroid and anesthetic injection. Osteitis pubis is characterized by inflammation of the pubic symphysis and usually presents as medial groin or symphyseal pain that is reproduced by thigh adduction. Avoiding the pubic periosteum when placing sutures and tacks reduces the risk of developing osteitis pubis. CT scan or MRI excludes hernia recurrence, and bone scan is confirmatory for the diagnosis. Initial treatment is identical to that of nerve entrapment; however, if pain remains intractable, orthopedic surgery consultation should be sought for possible bone resection and curettage. Irrespective of treatment, the condition often takes 6 months to resolve.⁷⁵

Cord and Testes Injury

Injury to spermatic cord structures may result in ischemic orchitis or testicular atrophy. Ischemic orchitis is likely caused by injury to the pampiniform plexus and not to the testicular artery. It usually manifests within 1 week of inguinal hernia repair as an enlarged, indurated, and painful testis, and it is almost certainly self-limited. It occurs in <1% of primary hernia repairs; however, this figure is larger for recurrent inguinal hernia repairs.⁷⁶ US will demonstrate testicular blood flow to differentiate between ischemia and necrosis. Emergent orchiectomy is only necessary in the case of necrosis. Injury to the testicular artery also may lead to testicular atrophy, which is manifest over a protracted period. Treatment for ischemic orchitis most frequently consists of reassurance, NSAIDs, and comfort measures. Intraoperatively, proximal ligation of large hernia sacs to avoid cord manipulation minimizes the risk of injury.

Injury to the vas deferens within the cord may lead to infertility. In open inguinal hernia repairs, isolating the vas deferens along with the cord structures using digital manipulation may cause injury or disruption. In laparoscopic approach, grasping the vas may result in a crush injury. Transections of the vas deferens should be addressed with a urologic consult and early anastomosis, if possible. Historically, surgeons and their patients speculated that synthetic material would increase the risks of mesh rejection, carcinogenesis, and inflammation; however, as mesh became used more frequently, these concerns did not manifest. Nevertheless, one study found prosthetic mesh may exert long-term deleterious effects upon the vas deferens, causing azoospermia.⁷⁷ Similar studies report varied results, though. A recent prospective study from the Swedish Hernia Registry discovered no difference in rates of patient-reported infertility between the general population and patients who underwent either mesh or tissue-based inguinal hernia repair.⁷⁸ Chronic scarring may lead to vas deferens obstruction, resulting in decreased fertility rates and a dysejaculation syndrome. Pain and burning during ejaculation are usually self-limited, and more common causes, such as sexually transmitted diseases, should be excluded.

In females, the round ligament is the analog to the spermatic cord, and it maintains uterine anteversion. Injury to the artery of the round ligament does not result in clinically significant morbidity.

Laparoscopic Complications

In general, the risks of the TEP technique mirror those of open anterior repairs, as the peritoneal space is not violated. Complications of transabdominal laparoscopy include urinary retention, paralytic ileus, visceral injuries, vascular injuries, and less commonly, bowel obstruction, hypercapnia, gas embolism, and pneumothorax. The most common complications of laparoscopic inguinal hernia repair are presented in this section.

Urinary Retention

The most common cause of urinary retention after hernia repair is general anesthesia, which is routine in laparoscopic hernia repairs. Among 880 patients undergoing inguinal hernia repair with local anesthesia only, 0.2% developed urinary retention, whereas the rate of urinary retention was 13% among 200 patients undergoing repair with general or spinal anesthesia.⁷⁹ Other risk factors for postoperative urinary retention include pain, narcotic analgesia, and perioperative bladder distention. Initial treatment of urinary retention requires decompression of the bladder with short-term catheterization. Patients will generally require an overnight admission and trial of normal voiding before discharge. Failure to void normally requires reinsertion of the catheter for up to a week. Chronic requirement of a urinary catheter is rare, although older patients may require prolonged catheterization.

Ileus and Bowel Obstruction

The laparoscopic transabdominal approach is associated with a higher incidence of ileus than other modes of repair. This complication is self-limited; however, it necessitates sustained inpatient observation, intravenous fluid maintenance, and possibly nasogastric decompression. Abdominal imaging may be helpful to confirm the diagnosis and to exclude bowel obstruction. Prolonged absence of bowel function, in conjunction with a suspicious abdominal series, should raise concern for obstruction. In this case, CT of the abdomen is helpful to distinguish anatomic sites of obstruction, inflammation, and ischemia. In TAPP repairs, obstruction occurs most commonly secondary to herniation of bowel loops through peritoneal defects or large trocar insertion sites; however, the use of smaller trocars and the preponderance of TEP repairs have reduced the frequency of this complication. True obstruction warrants reoperation.

Visceral Injury

Small bowel, colon, and bladder are at risk for injury in laparoscopic hernia repair. The presence of intra-abdominal adhesions from previous surgeries may predispose to visceral injuries. Direct bowel injuries may also result from trocar placement. In reoperative abdominal surgery, open Hasson technique and direct visualization of trocars are recommended to reduce the likelihood of visceral injury. Bowel injury may also occur secondary to electrocautery and instrument trauma outside of the camera field. Missed bowel injuries are associated with increased mortality. If injury to the bowel is suspected, its entire length should be examined, and conversion to open repair may be necessary.

Bladder injuries are less common than visceral injuries, and they are usually associated with perioperative bladder distention or extensive dissection of perivesical adhesions. As with bladder injuries encountered in open surgery, cystotomies must be repaired in several layers with 1 to 2 weeks of Foley catheter decompression. A confirmatory cystogram may be performed before catheter removal to confirm healing of the injury.

Vascular Injury

The most severe vascular injuries usually occur in iliac or femoral vessels, either by misplaced sutures in anterior repairs, or by trocar injury or direct dissection in laparoscopic repairs. In these cases, exsanguination may be swift. Conversion to an open approach may be necessary, and bleeding should be temporarily controlled with mechanical compression until vascular control is obtained.

The most commonly injured vessels in laparoscopic hernia repair include the inferior epigastrics and external iliacs. Although apparent upon initial approach, these vessels may be obscured during mesh positioning, and tacks or staples may injure them. Often, due to tamponade effect, injury to the inferior epigastric vessels is not apparent until the adjacent trocar is removed. If injured, the inferior epigastrics may be ligated with a percutaneous suture passer or endoscopic hemoclips.

If the tissue pressure exerted by pneumoperitoneum is greater than an injured vessel’s hydrostatic intraluminal pressure, bleeding will not manifest until pneumoperitoneum is released. The presentation of an inferior epigastric vein injury is often delayed because of this effect, and it may result in a significant rectus sheath hematoma. Accordingly, the surgeon should be aware of this intraoperative consideration.

Hematomas and Seromas

Hematomas may present as localized collections or as diffuse bruising over the operative site. Injury to spermatic cord vessels may result in a scrotal hematoma. Although they are self-limited, characteristic dark blue discoloration of the entire scrotum may alarm patients. Intermittent warm and cold compression aids in resolution. Hematomas may also develop in the incision, retroperitoneum, rectus sheath, and peritoneal cavity. The latter three sites are more frequently associated with laparoscopic repair. Bleeding within the peritoneum or preperitoneal space may not be readily apparent on physical examination. For this reason, close monitoring of subjective complaints, vital signs, urine output, and physical parameters is necessary.

Seromas are loculated fluid collections that most commonly develop within 1 week of synthetic mesh repairs. Large hernia sac remnants may fill with physiologic fluid and mimic seromas. Patients often mistake seromas for early recurrence. Treatment consists of reassurance and warm compression to accelerate resolution. To avoid secondary infection, seromas should not be aspirated unless they cause discomfort or they restrict activity for a prolonged time.

The incidence of recurrence is the most-cited measure of postoperative outcome following inguinal hernia repair. In evaluating the various available techniques, other salient signifiers of outcome include complication rates, operative duration, hospital stay, and quality of life. The following section summarizes the evidence-based outcomes of the various approaches to inguinal hernia repair.

Among tissue repairs, the Shouldice operation is the most commonly performed technique, and it is most frequently executed at specialized centers. A 2012 meta-analysis from the Cochrane Database demonstrated significantly lower rates of hernia recurrence (OR 0.62, CI 0.45–0.85) in patients undergoing Shouldice operations when compared with other open tissue-based methods.⁸⁰ In experienced hands, the overall recurrence rate for the Shouldice repair is about 1%.⁸¹ Although it is an elegant procedure, its meticulous nature requires significant technical expertise to achieve favorable outcomes, and it is associated with longer operative duration and longer hospital stay. One study found the recurrence rate for Shouldice repairs decreased from 9.4% to 2.5% after surgeons performed the repair six times.⁸² Compared with mesh repairs, the Shouldice technique resulted in significantly higher rates of recurrence (OR 3.65, CI 1.79–7.47); however, it is the most effective tissue-based repair when mesh is unavailable or contraindicated.⁸⁰

Hernia recurrence is drastically reduced as a result of the Lichtenstein tension-free repair.⁸³ Compared with open elective tissue-based repairs, mesh repair is associated with fewer recurrences (OR 0.37, CI 0.26–0.51) and with shorter hospital stay and faster return to usual activities.^84,85 In a multi-institutional series, 3019 inguinal hernias were repaired using the Lichtenstein technique, with an overall recurrence rate of 0.2%.⁸⁶ Among other tension-free repairs, the Lichtenstein technique remains the most commonly performed procedure worldwide. Meta-analysis demonstrates no significant differences in outcomes between the Lichtenstein and the plug and patch techniques; however, intra-abdominal plug migration and erosion into contiguous structures occurs in approximately 6% of cases.^84,87,88 The Stoppa technique results in longer operative duration than the Lichtenstein technique. Nevertheless, postoperative acute pain, chronic pain, and recurrence rates are similar between the two methods.⁸⁹ Perhaps the most compelling advantage of the Lichtenstein technique is that nonexpert surgeons rapidly achieve similar outcomes to their expert counterparts. Guidelines issued by the European Hernia Society recommend the Lichtenstein repair for adults with either unilateral or bilateral inguinal hernias as the preferred open technique.⁸⁵

Compared to open approaches, laparoscopic primary inguinal hernia repair produces equivalent recurrence rates and improved recovery time, pain prevention, and return to normal activities.⁹⁰ In a study of 168 patients randomized to either TEP or Lichtenstein repair, the 5-year recurrence rates were extremely low in both groups.^91,92 Similarly, a study of 200 male patients randomized to either ambulatory TEP or Lichtenstein repair demonstrated no recurrences in either group after 1 year.⁹³ Because laparoscopic surgery requires specialized instruments and longer operative times, its cost is higher than conventional open repair; however, the potential financial benefit of shorter recovery and decreased pain may offset these costs in the long term.

Perhaps the most salient difference between open and laparoscopic techniques is the number of cases needed to develop technical proficiency. In a randomized controlled trial performed by the Veterans Affairs Cooperative Study, 2-year recurrence rates were 10.1% in patients undergoing laparoscopic repair and 4.9% in those undergoing open repair, and the outcomes of laparoscopic repairs improved after each surgeon performed at least 250 cases.⁹⁴ More recently, Lal and colleagues found that surgeons sustained a decrease from 9% to 2.9% in postoperative recurrences after performing 100 TEP operations.⁹⁵ Other studies also suggest surgeons develop proficiency in these laparoscopic techniques after performing 30 to 100 cases; however, this estimate has decreased precipitously since laparoscopic technique was first introduced.^94,96,97

Although controversy persists regarding the utility of TEP vs. TAPP, reviews to date find no significant differences in operative duration, length of stay, time to recovery, or short-term recurrence rate between the two approaches. In TAPP repair, the risk of intra-abdominal injury is higher than in TEP repair. This finding prompted the IEHS to recommend that TAPP should only be attempted by surgeons with sufficient experience.⁴⁰ A Cochrane systematic review found that rates of port-site hernias and visceral injuries were higher for the TAPP technique, whereas TEP may be associated with a higher rate of conversion to an alternative approach; however, neither finding was sufficiently compelling to recommend one technique over the other.⁹⁷

The frequency with which the above inguinal hernia repair techniques are performed reinforces the importance of broad experience. The authors recommend that surgeons become proficient in several techniques to address different manifestations of inguinal hernias. Surgeons should tailor this experience to optimize outcomes for each patient.