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 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.
A. Layers of the abdominal wall in the anterior open approach to hernia repair. B. Identification of indirect and direct hernia sacs with retraction of the spermatic cord and ilioinguinal nerve. Ex. = external; SQ = subcutaneous.
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).
Anterior open exposure of the inguinal canal. m. = muscle; n. = nerve; v. = vein.
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-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.
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.
Bassini repair. A. The transversalis fascia is opened B. Reconstruction of the posterior wall by suturing the transversalis fascia (TF), the transversus abdominis muscle (TA), and the internal oblique muscle (IO) medially to the inguinal ligament (IL) laterally. EO = external oblique aponeurosis.
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.
Shouldice repair. A. The iliopubic tract is sutured to the medial flap of the transversalis fascia and the internal oblique and transverse abdominis muscles. B. The second of the four suture lines, reversing toward the pubic tubercle approximating the internal oblique and transversus muscles to the inguinal ligament. Two more suture lines affix the internal oblique and transversus muscles medially.
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.
McVay Cooper’s ligament repair.
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
Lichtenstein tension-free hernioplasty. m. = muscle; n. = nerve; v. = vein.
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.
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.
Plug and patch repair. A. A plug may be created from a flat piece of mesh, or a preformed, commercially available plug is placed in the internal ring. B. Final view of the repair following placement of the plug and patch.
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.
The Prolene Hernia System prosthesis.
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.
Extensive dissection of the preperitoneal space on both sides will accommodate a large prosthesis.
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.
Giant prosthetic reinforcement of the visceral sac. A. Exposure of the preperitoneal space. B. Dissection of the hernia sac from the spermatic cord. C. Reduction of the sac and elevation of the cord. D. Orientation and placement of the giant mesh.
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.
Operating room setup for laparoscopic inguinal hernia repair.
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.
Trocar placement for (A) transabdominal preperitoneal repair and (B) totally extraperitoneal repair.
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.
View of mesh placement in posterior repairs. A large mesh overlaps the myopectineal orifice.
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.
Balloon dissection of the preperitoneal space in a totally extraperitoneal inguinal hernia repair.
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.
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.
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.
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.
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.