Inguinal Hernia Repair Techniques
The most common type of hernia is an inguinal hernia. These occur in the groin, in the location where, before a male is born, the testicle migrates out through the three muscles of the inguinal canal, causing a weakening in the muscles in the area – the spermatic cord and the testicular blood vessels pass through the inguinal canal. The two deeper muscles of the inguinal canal (the internal oblique and the transversus abdominis muscles) are called the “floor’ of the canal. In women, the round ligament, which supports the uterus on the inside, and attaches to the pubic tubercle on the outside, passes through the inguinal canal. This opening is smaller in women. It is through this weakness where the hernia or defect occurs. Inguinal hernias can be classified as direct (medial hernias), or indirect (lateral hernias), or femoral hernias below the inguinal ligament.
The basic principle of every type of inguinal hernia repair is the reduction of the hernia contents and the prevention of passage of any intra-abdominal or pre-peritoneal contents to outside the musculo-aponeurotic plane of the abdominal wall. The goal of the hernia repair is to close the defect in the abdominal wall.
In the early days of hernia surgery suture repairs were the only repairs used. There are three popular suture repairs: modified Bassini, McVay, and Shouldice. Because suture repairs require pulling the muscles on the upper side of the defect to the fixed structures on the lower side, all create tension by necessity.
BASSINI: Bassini is credited with beginning the modern era of hernia surgery when he reported on his technique in 1887. Bassini used interrupted sutures to close the muscle on the upper side, to the inguinal ligament on the lower side, leaving a small opening for the spermatic cord and testicular blood vessels to come out. He divided the posterior wall of the inguinal canal, ligated the peritoneal sac, and constructed a sutured, three-layered tissue repair in 262 patients, with a failure rate of less than 3%. A simplification of his technique, the modified or “North American” Bassini repair avoided opening the posterior wall, but approximated the muscles of the floor to close the weakness with a single layer of sutures. However, it was difficult for regular general surgeons to match up to Bassini’s success rate – in fact, because of the “modification” of the technique, and less skill of many surgeons, the recurrence rate for this procedure is more in the range of 10-15%.
McVAY: Anson and McVay popularized a deeper anatomic repair that also required opening the floor of the inguinal canal, and approximated the upper muscles to the pectineal ligament (Cooper’s ligament). The “McVay” repair is more difficult to perform, but it became the preferred procedure for treatment of femoral hernias and many direct inguinal hernias.
SHOULDICE: In 1946, Shouldice, of Toronto, re-popularized Bassini’s original operation, and equally important, introduced the use of local anesthesia with sedation as the choice of anesthesia. The technically difficult Shouldice operation requires a “thinning” of the cord structures and a multi-layered closure of the floor with stainless steel wire, or nowadays with prolene suture. One of the problems with the Shouldice technique was the lengthy “learning curve” – the number of procedures a surgeon must do to become proficient enough to produce the same results as the experts. The reported results at the Shouldice clinic are excellent, with a recurrence rate of less than 1%, but few surgeons do the Shouldice operation today because of the difficulty in mastering the technique, and the introduction of tension free mesh repairs.
Suturing the muscles on the upper side of the inguinal canal (the conjoined tendon) to the inguinal ligament creates tension at the suture line. This feature of the Bassini operation, and other sutured repairs, is most disadvantageous. Even with relaxing incisions to reduce suture line tension, patients still experienced a high level of postoperative pain, prolonged disability, and unacceptable failure rates because of the tension.
Today, approximately 5-10% of repairs today are done with sutures – the rest are done with mesh.
In the early 1980’s, Dr. Gilbert and other surgeons, concerned about the unacceptably high incidence of hernia repair failures, began to evaluate the use of nylon mesh products for hernia repairs. Tension free techniques were proposed to reduce tension and post-operative pain. In 1960, Francis Usher, from Texas, described a technique for “bridging” the defect – he reported suturing a polyethylene mesh inlay patch deep to the transversalis fascia to do a “tension-eliminating” inguinal hernia repair. The mesh can be placed on top of the floor (onlay), beneath the floor, or both inside and out.
After visiting and operating with Rene Stoppa in Amiens, Dr. Gilbert was further convinced that the ideal place to position mesh is in the pre-peritoneal space behind the muscle, between the force of the hernia and the defect in the abdominal wall. He used nylon instead of wire for his Shouldice repair and reinforced it by placing mesh behind the muscle. This modified Shouldice technique further reduced the failure rate, and less than 0.5% for primary hernias and to 3% for recurrent hernias. The meh technique was easier for surgeons to master than the more complex suture repairs and has become the most popular method for inguinal hernia repair.
Lichtenstein (patch) repairs
Newman of New Jersey also described a tension-free technique for inguinal hernia using a polypropylene (Prolene) mesh onlay patch that he sutured over the opening in the floor of the inguinal canal. This technique, using a patch on the outside of the muscle, was popularized by Dr. Irving Lichtenstein and Dr. Parviz Amid. The Lichtenstein technique is currently the most commonly used open, tension-free procedure for groin hernias worldwide.
Plug and patch repairs
In 1985, Dr. Gilbert, at the Hernia Institute, borrowed Lichtenstein’s idea of creating a rolled plug and using it to repair indirect inguinal hernias. The intact indirect sac was dissected and pushed inward, and a hand-rolled mesh plug was placed into the internal ring to block the hernia opening. To complement this, a flat mesh onlay patch was used to reinforce the rest of the floor of the inguinal canal – hence the “plug and patch” technique. This was popularized further by Rutkow, and is still used by some surgeons today. This worked well, but the plug was annoyingly palpable in some thin patients.
To avoid these problems, and to protect a wider area, the mesh shape was changed from a rolled plug to an opened underlay patch, so it did not form a plug. Dr. Gilbert proposed and wrote about placement of mesh behind these muscle layers, using the hernia opening as a point of entry for deployment of the mesh like opening an umbrella, allowing it to unravel there – it became seated on the inside of the anterior abdominal wall. It literally blocked the peritoneal sac and its contents from protruding through the internal ring. Although no sutures were used, this technique proved satisfactory, providing a lasting repair for small and medium-sized indirect hernias.
This concept of placing mesh behind the muscles was the theory used by Gilbert when he developed the Prolene Hernia System, a two layer repair a technique in which two layers of mesh attached by a “connector” are placed both behind and in front of the muscles, requiring very few sutures. It is also the basis for other “posterior” repairs including those of Nyhus and Stoppa. Posterior repairs similar to these are re-gaining some popularity because of placement of mesh behind the muscle. The “posterior” repair concept is also the basis for laparoscopic repairs which were first described in 1991. Furthermore, the concept of protecting an opening from inside the defect has resulted in modification of the technique of repair of other hernias, including ventral, umbilical, and particularly, incisional hernias.
In 1997, having completed over 18,000 hernia repairs, Dr. Gilbert was commissioned by Ethicon, a subsidiary of Johnson and Johnson, to design the ideal mesh product for hernia repair. After consulting with engineers and biologists, he developed the Prolene Hernia System, a bilayer hernia repair device made of polypropylene. The Gilbert PHS technique is used by surgeons all over the world, including our surgeons at the Hernia Institute of Florida, where our experience has been with over 12,500 cases.
In 1989, general surgeons began using a small straw-like “port” device that allowed thin instruments to be placed into the abdominal cavity, thereby allowing for “minimally invasive” surgery. The laparoscope, a small camera inside a thin tube shaped instrument, allowed visualization inside the abdominal cavity, and other thin instruments such as scissors, dissectors, and ligating clip devices could be passed thru the ports to do the surgery. This was a major advancement, and surgeons could do procedures that resulted in less pain then conventional open surgery procedures. There was a great benefit for the patient, and within two years, 98% of all gall bladder procedures were done with the “laparoscopic” technique. Since that time, many other surgical procedures, including hernia repairs, are being done using the laparoscopic technique.
The first laparoscopic hernia repairs were done in 1991, over twenty years ago. Yet today, over twenty years later, approximately 10-15% of inguinal and femoral hernias are repaired using the laparoscope. Many surgeons started doing repairs laparoscopically, and have reverted back to open techniques. There are several reasons for this. The laparoscopic procedure, like the Shouldice suture technique, is more difficult to perform, and has a longer “learning curve”. It may take a surgeon over 200 cases before he can match his results with the open technique. It requires a general anesthesia, usually a Foley catheter, and there is a risk for more serious complications such as bowel, bladder, or vascular injuries.