You are leaving Medscape Education
Cancel Continue
Log in to save activities Your saved activities will show here so that you can easily access them whenever you're ready. Log in here CME & Education Log in to keep track of your credits.
 

 

CME

Inguinal Hernia: Anatomy and Management

  • Authors: Authors: Arthur I. Gilbert, MD, FACS, Michael F. Graham, MD FACS, Walter J. Voigt, MD FACS
  • THIS ACTIVITY HAS EXPIRED
Start Activity


Target Audience and Goal Statement

Inguinal Hernia: Anatomy and Management is intended for general surgeons and hernia specialists.

The goal of this activity is to define current treatment protocols and clinical strategies and describe state-of-the-art materials and techniques used in the surgical management of inguinal hernias.

On completion of this continuing medical education offering, participants will be able to:

  1. Identify the anatomical landmarks of the abdomen and groin relevant to hernia repair.
  2. Summarize the most commonly used tissue repair procedures.
  3. Explain the benefits of local, regional and general anesthesia in hernia repair.
  4. Describe the prosthetic devices and materials currently available for hernia repair.
  5. List the most common reasons for hernia recurrence and/or failed repairs.


Author(s)

  • Arthur I. Gilbert, MD, FACS

    Associate Clinical Professor of Surgery, University of Miami Medical School; Director of Surgery, Hernia Institute of Florida, Miami, Fla.

    Disclosures

    Disclosure: Arthur I. Gilbert, MD, FACS, has disclosed that he is a surgical consultant for Ethicon, Inc. He is President of the Florida Surgical Society and President of theAmerican Hernia Society.

  • Michael F. Graham, MD, FACS

    Hernia Institute of Florida, Consultant of Ethicon, Inc.

    Disclosures

    Disclosure: Michael F. Graham, MD, FACS, has disclosed that he holds consulting agreements with Ethicon, Inc.

  • Walter J. Voigt, MD, FACS

    Hernia Institute of Florida, Consultant of Ethicon, Inc.

    Disclosures

    Disclosure: Walter J. Voigt, MD, FACS, has disclosed that he holds consulting agreements with Johnson & Johnson and Prolene Hernia System.


Accreditation Statements

    For Physicians

  • Medical Education Collaborative, a nonprofit education organization, is accredited by the Accreditation Council for Continuing Medical Education (ACCME) to provide continuing medical education for physicians.

    Medical Education Collaborative designates this educational activity for a maximum of 2 hours in Category 1 credit towards the AMA Physician's Recognition Award. Each physician should claim only those hours of credit that he/she actually spent in the educational activity.

    Contact This Provider

For questions regarding the content of this activity, contact the accredited provider for this CME/CE activity noted above. For technical assistance, contact [email protected]


Instructions for Participation and Credit

There are no fees for participating in or receiving credit for this online educational activity. For information on applicability and acceptance of continuing education credit for this activity, please consult your professional licensing board.

This activity is designed to be completed within the time designated on the title page; physicians should claim only those credits that reflect the time actually spent in the activity. To successfully earn credit, participants must complete the activity online during the valid credit period that is noted on the title page.

Follow these steps to earn CME/CE credit:

  1. Read the target audience, learning objectives, and author disclosures.
  2. Study the educational content online or printed out.
  3. Online, choose the best answer to each test question. To receive a certificate, you must receive a passing score as designated at the top of the test. Medscape encourages you to complete the Activity Evaluation to provide feedback for future programming.
You may now view or print the certificate from your CME/CE Tracker. You may print the certificate but you cannot alter it. Credits will be tallied in your CME/CE Tracker and archived for 5 years; at any point within this time period you can print out the tally as well as the certificates by accessing "Edit Your Profile" at the top of your Medscape homepage.

The credit that you receive is based on your user profile.

CME

Inguinal Hernia: Anatomy and Management

processing....

The Evolution of Hernia Repair

Hernia (known as breuk in Dutch, rompure in French, keal in Greek and rupture in English) has plagued humans throughout recorded history, and descriptions of hernia reduction date back to Hammurabi of Babylon and the Egyptian papyrus (Figures 5 and 6).

 

Figure 5. Plates of ancient healing. Various trusses for containment of groin hernias.

 

Figure 6. Plates of ancient healing. Taxis for reduction of an incarcerated hernia.

Much of modern surgical technique results from the contributions of early surgeons (Tables 2 and 3), but it was not until the late 19th century that hernia surgeon Edoardo Bassini -- considered the father of modern day hernia surgery -- experienced any measurable degree of success in repairing hernias.

 

Table 3. Milestones in Hernia Repair: The Listerian Era

Marcy (1871)

Publication of original paper on antiseptic herniorrhaphy ("A New Use of Carbolized Catgut Ligature")

Czerny (1876)

Described ligating and excising the indirect peritoneal sac through the external ring

Kocher

Twisted and suture-transfixed the peritoneal sac in the lateral muscles. through the external ring

MacEwen (1886)

Reefed the peritoneal sac into a plug to block the internal ring.

Lucas-Championniere

Opened the external oblique aponeurosis to expose the entire inguinal canal.

 

Bassini: The Father of Modern Day Hernia Surgery

Bassini's aggressive approach was to perform "a radical cure of inguinal hernia," (the title of his presentation to the Italian Surgical Society in Genoa, in 1887). He reported only 8 failures in 206 hernia repairs during a 3-year period. His results were monumentally important, considering that before his work, failure rates ranged between 30% and 40% in the first postoperative year and almost 100% after 4 years.

Bassini's operation epitomized the essential steps for an ideal tissue repair.[7] He opened the external oblique aponeurosis through the external ring, then resected the cremasteric fascia to expose the spermatic cord. He then divided the canal's posterior wall to expose the preperitoneal space and did a high dissection and ligation of the peritoneal sac in the iliac fossa. Bassini then reconstructed the canal's posterior wall in 3 layers. He approximated the medial tissues, including the internal oblique muscle, transversus abdominus muscle and transversalis fascia to the shelving edge of the inguinal ligament with interrupted sutures. He then placed the cord against that newly constructed wall and closed the external oblique aponeurosis over it, thereby restoring the step-down effect of the canal and reforming the external inguinal ring (Figure 7).

 

Figure 7. Original Bassini operation. The canal's posterior wall is opened and the deep epigastric vessels are exposed.

There have been numerous modifications of Bassini's original technique, although many of the less detailed renditions have yielded poor results. Those that avoided opening the posterior wall, for example, resulted in suture-line tension between tissues at the most medial part of the inguinal canal just cephalad to the pubic bone. Some help was afforded the Bassini technique and other tissue repairs by the introduction of relaxing incisions by surgeons such as Wolfer, Halsted, Tanner, and McVay. (Figure 8).

 

Figure 8. Relaxing incision. Required for most tissue repairs to reduce tension on suture line.

Many other innovative surgeons have contributed to improved outcomes in hernia repair.[8-11] Annandale[12] described a posterior approach to groin hernia repair in 1876, although it failed to gain favor among surgeons. In 1920, Cheatle revitalized the use of the posterior approach.[13] He used a preperitoneal approach to repair abdominal wall defects, initially, through a lower midline incision, and later through a Pfannenstiel incision. Cheatle advocated this approach for indirect hernias and described dividing the peritoneal sac, and leaving the distal part of the sac in the cord. The proximal peritoneum was closed, and the defect of the widened internal ring was tightly sutured to prevent reherniation through it.

This technique was not well received until Henry[14] and, later, McEvedy[15] began using it for femoral hernias. More recently, US surgeons Nyhus, Condon, and Harkins[16] adapted the preperitoneal approach to repair direct and indirect groin hernias (Figure 9). In their procedure, abdominal wall defects were repaired with sutures and in some cases, mesh.

 

Figure 9. Preperitoneal suturing. The tranversus arch is sutured to the iliopubic tract.

Stoppa and colleagues[17] used the posterior approach to implant an impermeable barrier around the entire peritoneal bag, demonstrating that permanent repair of groin hernias does not require closure of the abdominal wall defect per se. Without having stated it, their repair used a tension-free technique (Figure 10). Wantz[18] furthered Stoppa's work by using it for unilateral hernia repair (Figure 11). Essential to these and all subsequent tension-free repairs is the application of a barrier prosthesis, usually a permanent mesh.[2] In Stoppa's approach, the mesh is held in place by intra-abdominal pressure, an application of Pascal's principle (Figure 12).

 

Figure 10. Stoppa procedure. The entire peritoneal bag is wrapped with a mesh graft. Expanding intra-abdominal pressure hold the graft in place without suture fixation.

 

Figure 11. Wantz procedure. Mesh draped between the peritoneum and the myopectineal orifice for unilateral hernia repair.

 

Figure 12. Bathtub drawing. Water pressure in the tub holds the stopper in the drain.

 

Contemporary Classical Repairs

Among the most notable contemporary classic hernia repairs are the Bassini, Halsted, Shouldice and, McVay (Cooper Ligament) repairs.

Modified Bassini. Bassini's original repair yielded outstanding results for a pure tissue technique, but, as noted above, problems occurred when surgeons failed to open the posterior wall. This operation became known as the "modified" or "North American" Bassini (Figure 13). By not opening the posterior wall, the wall tissue was damaged in its most medial portion by sutures placed under tension, and recurrences resulted, primarily in the pubic tubercle area. Thus, the failure of this operation in its first year was more likely due to an overlooked second hernia or to poor surgical technique, rather than a metabolic or tissue defect that might predispose to recurrent hernia.

 

Figure 13. Modified Bassini. The posterior wall is not opened. Sutures placed between the transversus arch and the inguinal ligament create tension on the tissues approximated.

The Halsted operation. Halsted, a contemporary of Bassini, published multiple generations of his operations for hernia repair, each one attempting to correct a flaw in the previous version.[8] Like Bassini, Halsted opened the canal's posterior wall to do a high dissection and ligation of the peritoneal sac in the iliac fossa. He made a point to thin the cord as much as possible and then did a 4-layer repair of the canal's posterior wall (Figure 14).

 

Figure 14. Halsted operation. The external oblique aponeurosis is closed under the spermatic cord thereby sacrificing the step-down effect of the canal.

Using the external oblique aponeurosis to reinforce the natural tissues of the posterior wall, Halsted's repair did not restore the step-down effect of the inguinal canal. This resulted in many recurrent indirect hernias and also produced an inordinately high incidence of postoperative hydroceles and atrophic testes. In a second version of his procedure, Halsted placed the cord against the posterior wall and sutured the transversus abdominus and internal oblique muscles over it for fortification. Although neither of these procedures is favored by surgeons today, Halsted made many other important contributions to surgery. Perhaps his most useful contribution to the advancement of hernia surgery was his demonstration that hernia repair could routinely be performed under local anesthesia.

Cooper ligament repair. Cooper was the first to describe the superior pubic ligament, although he never used it to surgically repair a groin hernia. The first Cooper ligament repair was done in 1897 by the Austrian surgeon, Georg Lotheissen, who used the superior pubic ligament in 2 patients who had lost their inguinal ligaments in the course of prior unsuccessful hernia repairs.[19]

McVay and Anson[20] revived Lothiessen's operation in 1942 (Figure 15). They considered the superior pubic ligament to be the ideal structure for reconstructing the posterior wall of an inguinal hernia, since it shares the same tissue plane and is derived from the same tissue origin as the transversus aponeurosis and the transversalis fascia. However, many surgeons who attempted this procedure found that it was sometimes difficult to approximate the transversus arch to the Cooper ligament. Doing so frequently resulted in considerable suture-line tension -- enough to require one or more relaxing incisions. Patients complained of considerable and prolonged postoperative pain, and failure rates became unacceptable. This procedure has, however, had value to surgeons by demonstrating the strength of the superior pubic ligament and showing its utility in large and difficult hernia repairs, including incisional hernias. It is a reliable structure to which prosthetic material can be fixed when a large defect must be spanned.

 

Figure 15. Cooper ligament repair. Approximation of the transversus arch to the superior pubic ligament creates more sutureline tension than any other pure tissue repair. A transition stitch must be used to avoid injury to the femoral vein.

Shouldice repair. Canadian surgeon E.E. Shouldice contributed substantially to hernia surgery in the second half of the 20th century. He founded a clinic that has since become a hospital devoted exclusively to the treatment of abdominal wall hernias. The Shouldice operation for hernia repair revitalizes Bassini's original technique.[21] It applies the principle of an imbricated posterior wall closure with continuous monofilament suture. At the Shouldice hospital, continuous stainless-steel wire is used for all layers of the repair, including the ligatures used in the subcutaneous layer (Figure 16). Local anesthesia is routinely used and bilateral hernias are usually repaired separately, 2 days apart. Patients walk to and from the operating room, begin exercise therapy on the day of surgery, and resume their usual activities within a reasonable time after the operation.

 

Figure 16. Shouldice repair. The posterior wall is imbricated to reconstructed and reinforced in 4 layers.

An unusual feature of the procedure is the routine sacrifice of the lateral cremasteric bundle, a structure that contains the external spermatic vessels and the genital branch of the genitofemoral nerve. Shouldice surgeons have not reported any ill effects related to this step. In fact, before using this technique, pubic tubercle recurrences were unacceptably high. The minor sensation loss that results from dividing that nerve has not proven to be a substantial or longstanding disability. However, when the lateral flap of the cremasteric fascia is sacrificed, ptosis of the testicle will occur. This can be prevented by fixing the distal pedicle of the cremasteric fascia to the external oblique when the canal is restored.

The Shouldice Hospital's specialized approach to hernia repair includes close patient follow-up. Because the Shouldice group believes that weight represents a critical factor in the success of all hernia surgery, the hospital often defers surgery until an overweight patient reaches an individualized, target weight.

The Shouldice repair has been considered the gold standard of hernia repairs for the last 4 decades, although its use has declined since the introduction of various tension-free prosthetic repairs. The Shouldice repair remains an excellent option, however, and has produced the best and most enduring results of any other pure tissue repair.

 

Use of Prosthetics in Hernia Repair

T he need for a satisfactory prosthesis for hernia repair has been recognized for more than a century. Various materials, including autografts (the patient's own tissue), have been tried. The most successful of the autografts is fascia lata, which has been used as suture material, a pedicle graft, and as a free transplanted graft. However, in addition to requiring a second operation to harvest it, fascia lata weakens and fails over time and dissolves in the presence of infection.

Artificial prostheses. Many authors have attempted to define characteristics of the ideal prosthetic material for hernia repairs (Table 4), although attempts to achieve this "ideal" have met with varying degrees of success (Tables 5 and 6). No currently available prosthesis is perfect or free of problems, and the choice of material thus requires compromise.[18] Surgeons do, however, have a large array of products from which to choose. (For a complete review of these products, see the recent Medscape Clinical Update "New Developments in Hernia Surgery.")

 

Table 4. Characteristics of an Ideal Prosthesis

The ideal prosthetic mesh should:

Not be physically modified by tissue fluids

Be chemically inert

Not excite inflammatory or foreign body reaction

Be noncarcinogenic

Not produce allergy or hypersensitivity

Be capable of resisting mechanical strain

Be capable of being fabricated in the form required, and constructed in a way such that sutures or cutting will not cause the mesh to unravel or fray

Be sterilizable[21,22]

Be permeable and allow tissue ingrowth within it

Stimulate fibroblastic activity to allow incorporation into tissue rather than sequestration or encapsulation

Be sufficiently pliable so as not to cause stiffness or to be felt by the patient

Strong enough to resist bursting by the maximum forces that can be created by intra-abdominal pressure or from an outer force

 

Table 5. Metal Prosthetic Graft Material

Silver filigree mesh (1900)

Became brittle and fractured and eventually extruded causing multiple sinuses and fistulas.


Fractured and caused sinus formation.

Toilinox (stainless steel)

Set up electrolyte reactions between ingredients if composition varied.

 

Table 6. Nonmetal Synthetic Prosthesis

Nylon (1944)

Replaced rubber, metals and animal products. Initially used for sutures, later knitted or woven into patches for hernia repair; disintegrates in tissue and loses most of its tensile strength within 6 months.

Polyethylene mesh (1958)
Polypropylene mesh (1962)

High-density polyethylene mesh (Marlex, 1958) resistant to chemicals and sterilizable, but unraveled after being cut. Modified to polypropylene mesh (1962). Available under various trade names (Hertra-2, Marlex, PROLENE, Surgipro, Tramex, Trelex). Available as a flat mesh as well as 3-dimensional devices (Altex, Hermesh3, PerFix Plug, PROLENE Hernia System).[23]

Polyester mesh (MERSILENE) (1984)

Composed of polyester fiber with the characteristics of filigree; can be inserted into narrow spaces without distortion.[16]

Expanded polytetrafluoroethylene

Teflon product; produces minimal adhesions when placed intraperitoneally.[22,24] Does not allow significant fibroblastic or angiogenic ingrowth; must be removed if infection occurs.

Polyglycolic acid mesh (Dexon)
Polyglactin 910 mesh (Vicryl)

Absorbable mesh; loses strength after 8 -12 weeks; should not be used as a sole prosthesis for the repair of abdominal or groin hernias

Complications related to the use of prosthetics. Materials composed of polypropylene and polyester insight a prompt and strong fibroblastic tissue response with minimal inflammation. This response consists of macrophages and giant cells, most of which eventually disappear. Fibroblastic activity allows rapid integration of the prosthesis into tissues; however, contraction of the enveloping scar tissue creates undesirable deformation of unsecured pieces of the monofilament; its free margins tend to curl, and small pieces roll up. There also have been some reports in the literature of freeform and preformed prosthetic mesh products migrating.

Serum or blood that accumulate in dead spaces surrounding any prosthesis becomes an excellent media for infection. Suction drainage is therefore advisable to eliminate dead space as well as to remove serum collections. Intestinal obstruction and fistula formation are serious complications and often require removal of the mesh/prosthesis. When a prosthesis is placed inside the peritoneal cavity, various degrees of visceral adhesions form depending upon the type of material used. When this is unavoidable, omentum or an absorbable prosthesis should be interposed between the mesh and the bowel.

Treatment of infection involves the application of basic surgical principles. Although most infections occur acutely, delayed infections involving nonabsorbable prostheses can occur months or years later. In the case of an acute infection of a groin hernia repair, it is advisable to quickly and widely open the wound (including the subcutaneous layer down to the external oblique) to avoid chronic sinus formation. A specimen should be taken for culture and sensitivity, irrigation and antibiotics started and healing observed by secondary intention. Frequent wound check to remove accumulated fluid is advisable.

If a prosthetic mesh had been used in the repair, it can usually be left in place if the above measures are employed promptly. If the wound closes, but a sinus continues to drain, it is likely that the mesh and all old suture material will need to be removed. Unlike early infection, when the mesh can be salvaged, late infection involving mesh requires the complete removal of the unincorporated material, although the incorporated mesh may be left undisturbed.

If the surgeon encounters an inflammatory granuloma in the course of repairing a recurrent inguinal hernia, it is prudent to avoid using a new prosthesis. Gram staining of the inflammatory granuloma at the time of surgery is not sufficiently reliable to exclude subsequent infection. In most cases of persistent infection related to a prior prosthetic repair, the culprit is the nature of the suture material rather than the graft itself. Multifilament and braided sutures, such as silk and cotton should be avoided.

 

Tension-Free Hernia Repair

T he most important advance in hernia surgery has been the development of tension-free repairs. In 1958, Usher described a hernia repair using Marlex mesh. The benefit of that repair he described as being "tension-eliminating" or what we now call "tension-free" (Figure 17). Usher opened the posterior wall and sutured a swatch of Marlex mesh to the undersurface of the medial margin of the defect (which he described as the transversalis fascia and the conjoined tendon) and to the shelving edge of the inguinal ligament. He created tails from the mesh that encircled the spermatic cord and secured them to the inguinal ligament.[22]

 

Figure 17. Usher's repair. The mesh is sutured from the transversalis fascia and conjoined tendon medially across the defect to the shelving edge of the inguinal ligament establishing a "tension-eliminating" repair.

Every type of tension-free repair requires a mesh, whether it is done through an open anterior, open posterior, or laparoscopic route. The most common prosthetic open repairs done today are the Kugel patch repair, the Lichtenstein onlay patch repair, the PerFix plug and patch repair, and the PROLENE Hernia System bilayer patch repair (Figures 18-21).

 

Figure 18. Lichtenstein onlay patch. Mesh is sutured from the transversus arch to the shelving edge of the inguinal ligament creating a "tension-free" repair.

 

Figure 19. Perfix Plug. Flower-shaped polypropylene mesh plug with multiple petals, and onlay graft with slit to accommodate the spermatic cord.

 

Figure 20. Kugel Patch. "Race-track" oval shaped polypropylene mesh graft with pocket for insertion and larger gauge polypropylene ring to hold graft's flat shape.

 

Figure 21. PROLENE Hernia System (PHS) bilayer patch repair. Bilayer polypropylene mesh. Three-in-one device with round disc for properitoneal repair, plug effect of connector, and oblong shaped onlay component.

The Stoppa-Rives giant prosthetic repair of the visceral sac is also an important tension-free technique done through an open posterior approach[17] (Figure 10). It has been described as "the ultimate weapon" to repair recurrent hernias. In this procedure, the surgeon uses a large sheet of Mersilene mesh to separate the peritoneal bag and its contents from the defect(s) in the abdominal wall. The defects in the abdominal wall are left unsutured.

Newman introduced a less complicated tension-free repair procedure in which the posterior wall is invaginated and Marlex mesh is sutured as an onlay graft to the transversus arch superiorly, the inguinal ligament inferiorly, and the pubis medially. The tails are crossed lateral to the cord and fixed to the inguinal ligament lateral to the internal ring. This technique does not require opening the posterior wall, and the mesh acts more like a lid than a stopper. Newman performed the procedure on 1600 patients and gifted this operation to Lichtenstein, who popularized it to become the most frequently done hernia repair in the United States and possibly worldwide.

The PerFix Plug repair of direct and indirect hernias is an adaptation of Gilbert's free-formed umbrella-shaped plug, which was initially used as a plug in the internal ring for treatment of indirect inguinal hernias (Figure 22). Currently, the PerFix Plug is manufactured and placed in the internal ring and fixed with sutures to the surrounding tissues. When a direct hernia is present, the PerFix Plug is used in a similar fashion. When pantaloon or unusually large direct hernias are present, multiple plugs are sewn together to repair the defect. In addition to the plugs, an onlay patch is provided, which can be used with or without sutures over the posterior wall and around the spermatic cord lateral to the internal ring.

 

Figure 22. The PerFix plug repair of direct and indirect hernias. It adapts Gilbert's free-formed umbrella-shaped plug, which was initially used as a plug in the internal ring for treatment of indirect inguinal hernias.

The Kugel patch is a polypropylene, oblong-shaped mesh with a thickened polypropylene thread that encourages the mesh to flatten. The Kugel approach is through a small incision above the internal ring. The preperitoneal space is entered and dissected free. An indirect sac is retracted or transsected, and the threshold of the internal ring is thereby freed of the peritoneal sac. The prosthesis is inserted and fixed in place with a single suture and then held in place by the natural intra-abdominal forces (Pascal's principle) (Figure 23). In this procedure, the spermatic cord anterior to the interior ring is not handled. This approach is designed to protect the internal ring and posterior groin wall as well as the femoral canal.

 

Figure 23. A cork in a barrel works more effectively than a cork outside the barrel.

The PROLENE Hernia System bilayer patch device (Figure 21) has a combined onlay graft (like a Lichtenstein repair) and underlay graft (like a Stoppa or Kugel patch); these are held together by a connector (like a plug). The external oblique aponeurosis is opened through a 5-cm groin incision, the spermatic cord is elevated, and an anterior space is created for placement of the onlay component of the device (Figure 24). If an indirect hernia sac is present, it is invaginated through the internal ring. If a posterior wall hernia is present (direct hernia), the defective tissue is circumscribed. In either case, the preperitoneal space (space of Bogros) is dissected free with a 4 x 4 sponge (Figure 25).

 

Figure 24. Finger dissection of the anterior space is best done when first reaching this tissue plane.

 

Figure 25. Sponge dissection, posterior space. Sponge traction in the properitoneal space is more effective in creating the space than is the gloved finger of the surgeon.

The head, neck, and shoulders drawing in Figure 26 illustrates the concept of dissecting the shoulders of the peritoneal sac. Separating the peritoneum from the transversalis fascia develops the shoulders. The PROLENE Hernia System is inserted through either of these defects. If a pantaloon hernia exists, the deep epigastric vessels are divided, and the two defects are converted to a single defect. The entire PROLENE Hernia System is inserted through the posterior wall defect or internal ring. The underlay component is deployed so that the edge of the graft is at complete distraction from the connector (Figure 27). The lateral portion of the underlay graft descends caudad to the Cooper ligament, thereby protecting the femoral canal. The onlay graft is extracted and placed against the posterior wall into the anterior space beneath the external and internal oblique muscles and laid against the transversus arch down to and over the pubic tubercle. A few sutures are placed in the onlay graft. At minimum, one is placed at the pubic tubercle, one at the mid portion of the transversus arch, and one at the mid portion of the inguinal ligament. The spermatic cord is accommodated with a central or lateral slit in the onlay component.

 

Figure 26. Freeing the shoulders of the sac creates the optimum space.

 

Figure 27. The forefinger unfurls the underlay component of the PROLENE Hernia System device.