Inguinal hernia

The inguinal hernia repair continues to be the most common operation in general surgery. Discussing the latest scientific findings, we have prepared this article to present a state-of-the-art approach to the inguinal hernia repair. This approach is used for discussing the general principles of hernia repair in German military hospitals. Quality assurance requires that all hernias be classified during surgery on the basis of a standardized approach for an objective comparison of treatment and outcomes. Our approach to hernia repair considers the age of the patient, the diameter and location of the hernia and whether or not the herniation is recurrent. The Shouldice technique performed under local anesthesia is defined as the standard approach in young patients. The use of prosthetic meshes continues to be the ideal method for repairing large medial fascial defects and recurrent hernias. Endoscopic procedures are particularly suitable for the bilateral repair and recurrent hernias.

Introduction

The past 15 years have witnessed fundamental changes in the surgical repair of inguinal hernias. Apart from the conventional Shouldice repair, endoscopic and open procedures, which involve covering the abdominal wall defect with a biocompatible mesh, have gained widespread use. With approximately 200,000 operations that are performed annually in Germany, the surgical repair of hernias continues to be the most common operation in general surgery in Germany.1,2 Likewise, the treatment of hernias is the most frequent operation in general surgery in the German armed forces. Every year more than 3,000 military and civilian patients receive surgical treatment of the inguinal hernia in German military hospitals. This large number of operations emphasizes the need for discussing and comparing modern repair techniques and their outcomes. The success of surgery can be measured on the basis of recurrence rates and patient comfort. Recent data show that up to 15% of all operations are performed to repair recurrent hernias.3,4 Given an incidence of inguinal hernia of 2% to 5% in males and 0.3% to 0.5% in females,5 economic aspects, quite apart from the implications for each individual patient, are playing an increasingly important role. The past decade has witnessed dynamic changes in the surgical repair of inguinal hernia. Since the early 1990s, when endoscopie procedures gained in popularity, mesh techniques have almost become the new method of choice for repairing hernias in Europe. At the same time, the conventional Lichtenstein technique has also become more widely used. At the end of the 1990s, there was great controversy about the long-term safety of implanted synthetic meshes.6,7 As a result of this discussion, it was recommended that synthetic material be used with great caution, especially in patients under 40 years of age, not least because the conventional Shouldice technique continued to be an appropriate alternative with which satisfactory outcomes and low recurrence rates could be achieved. In the past 5 years, however, considerable progress has been made in developing new types of meshes. Today, large pore-sized and low-weight meshes are available which are partially absorbable and have more favorable biological properties than their predecessors.8,9 This makes it all the more difficult for the surgeon to decide what surgical procedure is best suited to which case.

We have used a recent analysis of surgical procedures in an attempt to find answers to the following question: Which techniques are currently recommended for the surgical repair of primary unilateral hernias, primary bilateral hernias, recurrent hernias, scrotal hernias and incarcerated hernias?

Current Surgical Procedures

The Shouldice Repair

This technique was introduced by Shouldice10 from Toronto, Canada, and is a modification of the repair technique by Bassini,11 who -as far back as 1890 -was the first to define one of the basic principles of this repair method: a series of suture lines is used to reinforce the posterior wall of the inguinal canal and narrow the internal inguinal ring. Unlike Bassini's all-layer interrupted suture, the Shouldice approach to repairing the posterior wall of the inguinal canal begins at the level of the transversalis fascia. The transversalis fascia is divided parallel to the inguinal ligament and a double layer of transversalis fascia is sutured to the inguinal ligament using continuous suture lines. This is reinforced by an additional continuous double layer of low-tension suture which is placed between the internal oblique muscle and the lower part of the inguinal ligament. As a result, the defect is repaired and the inguinal ring is reconstructed using four layers of low-tension suturing. This operation can be performed under local anesthesia.

The Lichtenstein Repair

In this procedure, which uses a conventional anterior approach, a prosthetic mesh is implanted between the external aponeurosis and the internal oblique muscle to form a strong posterior wall of the inguinal canal. This method was pioneered by Lichtenstein as early as 197012,13 and has been practiced widely since 1989. In contrast to the Shouldice method of repair, the defect is covered with a patch of synthetic material in an attempt to reinforce the posterior wall of the inguinal canal. This technique is also known as the Lichtenstein tension-free hernioplasty3 and, like the Shouldice method, can be performed under local anesthesia.

The Transabdominal Preperitoneal (TAPP) Approach to Hernia Repair

This endoscopic procedure was first described by Bogojavalenski in 1989.14 Following the induction of a pneumoperitoneum, this procedure involves the transabdominal preperitoneal laparoscopic placement of a sufficiently large prosthetic mesh (10 × 15 cm) over the hernia defect.

The Totally Extrapreperitoneal (TEP) Approach to Hernia Repair

In this procedure, a balloon trocar is used to create a working space between the abdominal wall and the peritoneum. Then the prosthetic mesh is placed endoscopically between the musculature of the abdominal wall and the peritoneum. This method was popularized by McKernan and Laws in 1993.15 Compared with the TAPP approach, the extraperitoneal procedure has the advantage that major complications such as vascular and visceral injuries, adhesion formation and subsequent bowel obstruction, and trocar hernias are less likely to occur. Endoscopic procedures require general anesthesia. It is possible to repair bilateral hernias at the same time through a single incision.

The above description of the most common surgical procedures clearly shows that two different repair principles can be distinguished. On the one hand, the Shouldice method of repair involves closing the defect by suturing without tension natural endogenous tissue to the inguinal ligament. On the other hand, there are open (Lichenstein) and endoscopic (TEP or TAPP) procedures in which synthetic material is used to achieve a tensionfree repair of the hernia.

Classification of Inguinal Hernias

Because the risk of recurrence of a large medial hernia is approximately five times higher than the risk of recurrence of a small lateral hernia,5 it is important to assess and document the size and location of each hernia. Only on the basis of complete documentation can the long-term outcomes of different types of hernia repair be objectively compared and reproduced as required by quality assurance.

A review of the pertinent literature shows that there are a great variety of classifications, most of which, however, have not gained widespread use.16 The classifications which were published by Halverson and McVay17 in 1970 and by Gilbert18 in 1989 take into account the anatomic and functional aspects of the inguinal region but provide only insufficient information about the location in connection with the size of the hernia.

The Nyhus classification,19 which dates back to 1993 and has thus far been the most popular classification system, distinguishes between four types of hernias. Using this classification, however, it is impossible to obtain information about direct and indirect inguinal hernias and their respective sizes. In addition, all recurrent hernias, irrespective of their location and size, are classified as type IV hernias. This classification does not consider the great variability of recurrent hernias.

What was needed was a new classification of inguinal hernias which takes into account all types of hernias and their location, which includes a quantitative measurement of the size of the defect and which can be successfully applied in actual clinical practice. In 1994, Schumpelick et al.20 published a new approach which involves classifying hernias during surgery. This classification system not only takes into account the size and location of hernias but is also easy to apply in actual clinical practice even when an endoscopie procedure is performed. The letters "M" (medial or direct), "L" (lateral or indirect), and "C" (combined) indicate the location of the hernia sac. "F" refers to femoral hernias. The size of the hernia sac is classified as "1" (not exceeding 1.5 cm), "2" (between 1.5 cm and 3 cm), or "3" (exceeding 3 cm; Table I). In the case of combined hernias, the sizes of the hernia sacs are added together. When conventional procedures are performed, the surgeon uses the tip of his index finger for assessing the size of the defect. When an endoscopie procedure is performed, the 1.5-cm-long limb of endoscopie scissors can be used as a reference size.20 Thus, Schumpelick's classification system is easy to perform and suitable for daily clinical practice. The letter "R" refers to recurrent inguinal hernias.

Discussion

The Surgical Repair of Hernias over the Past 10 Years

Since the introduction of endoscopie hernia repair, this type of surgery has become the method of choice in many European hospitals. As a result of the initial enthusiasm that was generated by the prospect of using videoendoscopic techniques for almost all kind of operations, the age of the patient and the type of hernia tended to play only a minor role in the choice of surgical procedure. The past 5 years have witnessed a change in this general trend. Compared with other techniques, endoscopie procedures require far more infrastructure and equipment as well as special expertise on the part of the surgeon and accordingly require a substantial surgical learning curve.21,22 A review of the literature gives evidence of a wide variety of recurrence rates (between 0.5% and 18.4%) after TEP, which is usually not only associated with a longer operating time23 but also appears to be a technically more demanding procedure which is not always reproducible.24-26 Furthermore, endoscopic procedures, unlike conventional methods, cannot be performed under local anesthesia. Another aspect which continues to cause controversy is the long-term biocompatibility of synthetic meshes, the size of which is usually 10 × 15 cm.6,7 When an endoscopic procedure is performed, it is impossible to decide on the basis of intraoperative findings whether or not to use a mesh. The most important problem associated with endoscopic procedures, however, is the risk of major complications such as vessel and viscera injuries, which, although uncommon, may be lifethreatening.22,24,27 Mechanical bowel obstruction caused by intraperitoneal adhesions is often described as a late effect of endoscopie surgery. This complication has been reported more often in connection with TAPP but can also occur with TEP.28 Recurrence rates of 0.5% to 5% show that satisfactory long-term outcomes can be achieved with surgical procedures which are technically easy to perform. It should be noted that endoscopie techniques are particularly suitable for the simultaneous repair of large medial hernias on both sides and for the repair of hernias with multiple recurrences after conventional surgery.

Among the surgical techniques which are currently practiced, the Lichtenstein method of repair is the easiest to learn and particularly suited to training purposes. Compared with endoscopic techniques, the risk of major complications is far lower.22,24,27 In addition, the Lichtenstein method usually requires only one-half to one-third of the prosthetic material that is needed for TEP or TAPP. Another advantage of the Lichtenstein technique is that the surgeon can decide on the surgical procedure on the basis of intraoperative findings because the Lichtenstein method of repair uses almost the same initial approach to the inguinal region as the Shouldice method. The Lichtenstein technique can be performed under local anesthesia. The recurrence rate was found to be as low as 0.6% to 5% in controlled stuudies.29,30 Whereas studies show similar outcomes for the Lichtenstein method and the technically simple TEP method, endoscopic procedures show much wider variation in the results achieved (from 0.5% to 18.4%).

In the mid-1990s, the long-term biocompatibility of synthetic implants caused much controversy in the surgical community.6,7 On the one hand, many feared that the implanted material could begin to migrate in the long run. On the other, the heavy close-meshed implants were found to shrink and lead to scar formation; patients repeatedly complained of discomfort caused by these conglomerates of mesh and scar tissue. Moreover, chronic inguinal pain syndromes were found to occur more often after the implantation of meshes.24,26 As a result of this discussion, it was recommended that foreign material should be used with great caution, especially in young patients (under 40 years of age). The conventional Shouldice technique continued to be an appropriate alternative with which satisfactory outcomes and acceptable recurrence rates (on average 3.5% to 8%) could be achieved.1,4 The Shouldice method of repair, in which a double layer of transversalis fascia is sutured to the inguinal ligament, has proven to be less suitable for the repair of very large medial fascial defects. In these cases, the absence of a sufficient amount of natural material for reconstruction is conducive to the recurrence of the hernia. Whereas many doubt that the Shouldice method is suitable for the repair of recurrent hernias, the use of prosthetic meshes for a large medial recurrent hernia after a Shouldice repair is undisputed.31

In the past 5 years, major progress has been made in developing new material-reduced types of meshes. Today, large-meshed and low-weight implants are available which are partially absorbable and have more favorable biological properties than their predecessors. Large pore-sized meshes have the advantage that, on the one hand, no adverse body reactions to excessive scarring occur and that, on the other, they induce the body to form a more flexible and sufficiently stable "mesh of scar tissue." This also leads to a less severe inflammatory response and reduces the risks associated with the implantation of foreign material.8,9 Although efforts to further improve existing material are still underway, it has been possible in the past to extend the indications for the implantation of synthetic material for the repair of hernia and especially for the repair of large medial fascial defects.

The most recent meta-analysis of surgical methods for inguinal hernia repair was published by Grant31 in 2002 on behalf of the EU Hernia Trialists Collaboration. Open-mesh techniques were compared with nonmesh techniques on the basis of 20 validated studies. The conventional open mesh technique (Lichtenstein) was associated with a lower rate of recurrence. Although there were no clear differences between mesh and nonmesh groups as far as complications were concerned, there was evidence of lower rates of persisting pain and quicker recovery following the Lichtenstein technique. In addition, endoscopic and conventional procedures were compared on the basis of 41 studies. On the one hand, endoscopic procedures were associated with longer operating times and with higher risks; on the other, the advantage of these procedures is that they cause less pain and promote a speedier return to normal activities. Once again, the mesh techniques showed a lower recurrence rate than the open nonmesh techniques.

Conclusions: Recommendations for the Surgical Repair of Hernias in German Military Hospitals

The following recommendations for the surgical treatment of hernias can be given on the basis of the latest validated scientific data (Table II):

1. Primary unilateral hernias: A prosthetic mesh is used especially for the repair of a large medial defect or in cases where the posterior wall of the inguinal canal has been destroyed. This applies to M2-3, L2, and C3 hernias according to the Schumpelick classification and to III a, b, c hernias according to the Nyhus classification. An implantation is not indicated in the absence of a medial defect (Schumpelick's Ll hernias and Nyhus's I and II hernias). Meshes should be used in young patients only in very rare cases.

2. Primary bilateral hernias: Both open and endoscopie procedures are used. Endoscopie procedures are contraindicated in patients with health problems that prohibit the use of general anesthesia for elective hernia repair and in young patients for whom the use of large meshes for the repair of bilateral hernias would involve high long-term risks associated with the implantation of foreign material.

3. Recurrent hernias: The Lichtenstein technique or the TEP or TAPP approaches should be used for the repair of recurrent hernias following conventional nonmesh repair. A surgical exploration including the coverage of the defect or an endoscopie procedure should be used for the repair of recurrent hernias following mesh repair. The Lichtenstein technique should be used for the repair of recurrent hernias following TEP or TAPP.

4. Scrotal hernias: Large scrotal hernias should be repaired using a conventional operation and the implantation of a mesh. Endoscopie procedures should be used only rarely because of the increased operative risk. In individual cases, hernia repairs in young adults can be performed without a mesh.

5. Incarcerated hernias: Apart from the aforementioned recommendations for the repair of hernia on the basis of intraoperative findings, an explorative laparoscopy should be performed to assess the vitality of the incarceration. In the case of unclear findings, the vitality of an incarcerated bowel loop must be assessed using laparoscopy.

A differentiated treatment concept is currently the only basis on which a surgeon can choose the "perfect" surgical procedure which is tailored to the individual patient's requirements and takes into account his or her age and type of hernia. Ideally, the decision on whether or not to implant a mesh should be made during surgery. There is no standard method of hernia repair that can be used as a "one type fits all" approach.

References

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29. Vrljland WW, van den ToI MP, Luijendljk RW. et al: Randomized clinical trial of non-mesh versus mesh repair of primary inguinal hernia. Br J Surg 2002: 89: 293-7.

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Guarantor: LtCol Robert Schwab, GAF MC

Contributors: LtCol Robert Schwab, GAF MC; Col H. Peter Becker, GA; Maj Volker Fackeldey, GA

Department of General Surgery, Central Military Hospital, Koblenz, Teaching Hospital of the University of Mainz-Medical School, Germany.

This manuscript was received for review in March 2003 and accepted for publication in January 2004.

Reprint & Copyright © by Association of Military Surgeons of U.S., 2004.

Copyright Association of Military Surgeons of the United States Dec 2004
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