INGUINAL HERNIAS

The history of inguinal hernia surgery is a long one with the evolution of repair techniques over quite a long period of time.  Indirect inguinal hernias are a congenital problem and therefore are frequently seen, and have been frequently a problem in the history of the human race.

In medieval times one approach to the problem of inguinal hernia was cauterization of the inguinal area creating a deep burn scar which hopefully obliterated the hernia sac.  Need less to say, complications from this rather brutal method of treatment were many.

An anatomic understanding of the basis of inguinal hernia and the structures in the groin allowed a more anatomic approach to inguinal hernia repair and several very good anatomic approaches were developed over the years including the Halsted, Bassini and the McVey repair.  The McVey repair was particularly a good anatomic approach and the recurrence rate for inguinal hernia with the McVey repair was probably around 5 to 7 percent.  This was still too high for many surgeons and the search for an improved method of hernia repair has been ongoing.

More recently the Lichtenstein hernia repair has shown a recurrence rate of approximately one or two percent in experienced hands and this has become arguably the gold standard for hernia repair in the United States.  This repair involves the placement of Marlex mesh in approximation to the muscle layers of the inguinal canal.  This substance incorporates into the tissue producing, as in the middle ages, a dense scar which resists recurrence.  Laparoscopic hernia repair has also gone through several different iterations and now is rather widely offered.  Laparoscopic hernia repair also relies on placement of prosthetic mesh in approximation to the tissue.  Its proponents offer that the technique causes less postoperative pain than the Lichtenstein technique.

It is between these two techniques, that most patients need to choose.  The advantage of the Lichtenstein repair is a 20 year track record in the United States with a predictable incidence of recurrence and widespread familiarity with the procedure.  This hernia repair is involved with a low incidence of nerve entrapment problems, and essentially no potential for intra-abdominal viscera to form adhesions to the Marlex mesh.  There is very little chance of damage to intra-abdominal contents except in the rare case of a so-called sliding inguinal hernia.  The use of Marlex mesh does allow for the possibility of postoperative wound infection, and when wound infection occurs in the setting of prosthetic material, this prosthetic material must be completely removed and hernia repair accomplished by another method.  This is obviously a bad outcome for the patient and may require several surgeries to completely address this complication.

The laparoscopic approaches do not have as long of a track record as the Lichtenstein hernia repair, but the preperitoneal laparoscopic approach appears to come near to the recurrence rate of the Lichtenstein hernia repair although follow-up is not as long .  With the laparoscopic hernia repair, there is more danger of injury to intra-abdominal contents because it involves the placement of trochars into or very nearly into the abdomen.  It has at least as much potential for brisk bleeding as the Lichtenstein repair.  Because the Marlex mesh or polypropylene mesh is placed into closer proximity to the abdominal viscera, the possibility of adhesion formation between the abdominal contents and the mesh is more likely with these laparoscopic approaches.  The problems of infection remain essentially the same although removal of the intra-abdominal mesh is probably a more difficult proposition.  Laparoscopic inguinal hernia repair may leave certain mass lesions of the spermatic cord in place such as a so-called lipoma of the cord which can later be mistaken for recurrent hernia.  The laparoscopic approach also has some unique potential for temporary neurologic problems particularly involving the lateral femoral cutaneous nerve.  These neurologic problems usually subside within 6 weeks however.

Types of inguinal hernias

The general nature of hernias is a thinning or absence of the muscular layer of tissue in such a fashion that the abdominal viscera becomes covered by only a layer of skin, subcutaneous tissue, and the lining of the abdomen called the peritoneum which is an extremely thin layer.  This clinically appears to be a weakness in the abdominal wall are groin.  Repair efforts are directed toward reinforcing or replacing the thinned or absent muscular layer

There are two main types of inguinal hernias and three other hernias that present similarly but are much more uncommon.

Indirect inguinal hernia is the most frequent kind of hernia and has a congenital basis.  It represents a dissection of the lining of the abdomen called the peritoneum down along the spermatic cord in males or the round ligament in females which are anatomic structures that go from inside the abdomen down into the groin or the vaginal area.  Intra-abdominal contents can follow this so-called sac of peritoneum and this is what comprises this hernia.  Essentially every pediatric hernia is of this type.

The other main type of inguinal hernia is the direct inguinal hernia and occurs mostly in older age groups.  It is virtually nonexistent in the pediatric population.  It involves a thinning of the muscular layers beneath the the spermatic cord or the round ligament in such a fashion that the tissue bulges outward and the intra-abdominal contents can follow this bulge.  Repair of both direct and indirect inguinal hernias are done in a very similar fashion and the incisions for these are the same.

Femoral hernia is a variant of inguinal hernia but instead of bulging in the groin, frequently bulges in the upper thigh, although it may be difficult to distinguish this from the other two.  Frequently femoral hernias are mistaken for an enlarged lymph node in the thigh or some other sort of mass.  They frequently present with acute pain because their contents become trapped in the hernia sac.  This is referred to as incarceration.  These hernias are frequently not recognized until incarceration occurs and often have to be operated on emergently.  Once again the repair of these hernias ,at least when done electively, is very similar to the repair for the other two types of hernia.  In the case of incarceration, a midline incision may need to be performed if the entrapped contents of the hernia sac become gangrenous.

Obturator hernia is a very unusual form of hernia and presents simply with pain in the thigh.  The diagnosis of an obturator hernia is difficult to make, and it is frequently not appreciated what the actual diagnosis is prior to exploratory surgery.  CT scan of the abdomen is now very good way to look for obturator hernia.

Spigelian hernia is also a very unusual hernia defect and occurs in the groin in a higher location than the typical inguinal hernia.  It involves a protrusion of the lining of the abdomen through a congenitally weak spot where muscle layers cross.  Sometimes the diagnosis of spigelian hernia is not made properly preoperatively and this leads to some intraoperative confusion.

Emergencies: Incarceration and strangulation

Incarceration of any of these kinds of hernia can occur and once again this involves entrapment of the intra-abdominal contents in the hernia sac.  When the intra-abdominal contents become gangrenous, frequently a midline incision may be required to adequately care for this problem since bowel resection may be required.  Incarceration is a surgical emergency and the gangrenous variant of this is referred to as strangulation.  Certainly any hernia  contents that suddenly become unable to be reduced merit immediate physician attention.

It is because of the possibility of incarceration or strangulation that elective repair of hernias is urged by the surgical community.  Certainly elective repair is easier on the patient and has much fewer complications and is more likely to result in complete resolution of the problem than an emergency surgery especially one done in the face of infected tissue.

Preoperative evaluation

Patients with a new inguinal hernia without any underlying medical conditions and without any previous surgery are good candidates for either laparoscopic or Lichtenstein type hernia repairs.  The choice is very much up to the patient in these cases although the surgeon may have a preference.  Patients with specific health-care problems such as cardiac disease or asthma may require specific evaluation of these problems in relation to their surgical procedure.

Patients with a previous hernia repair on the same side, may be counseled to undergo laparoscopic hernia repair as this can be done without going through previously scarred tissue.  Again individual surgeon preference can be an issue.  Patients with bilateral hernias frequently are also counseled to undergo laparoscopic hernia repair since this may be one area in which there truly is less postoperative pain.

Pediatric patients if born prematurely, are usually counseled to wait until such time as their age equals the usual term of pregnancy.  Respiratory complications are more frequent if the patient is operated on earlier, and if the patient requires an earlier operation, the patient should be observed overnight in a monitored setting.

Patients of 50 or older may have a predisposing cause for a new hernia and usually require some workup.  Many surgeons suggest that preoperative colonoscopy be done to exclude colon polyps and colon cancer.  They also frequently counsel  preoperative chest x-ray since a chronic cough can cause the presentation of inguinal hernia.  Male patients are usually screened for prostate disease either with a physical examination, a PSA (prostate hormone) test, or usually both.

Performance of the procedure

Most inguinal hernia surgery today is done on an outpatient basis.  The patient is asked to refrain from eating or drinking anything within approximately 8 hours of the anticipated procedure.  They are usually brought to the outpatient surgery department 1 1/2 or one hour prior to the procedure to allow for registration, starting IVs, and anesthesia  related activities.  The patient is usually administered a broad-spectrum cephalosporin type antibiotic if the use of prosthetic mesh is anticipated.  The patient is usually shaved either in the outpatient area or in the operating room prior to the procedure.  Shaving the night before the procedure can result in an increased number of infections.

If Lichtenstein hernia repair is done, local anesthetic, spinal anesthetic, or general anesthetic can be  chosen and is usually a matter of  patient preference.  For laparoscopic hernia surgery, general anesthetic is necessary.

The patient can usually go home several hours after the procedure.  Narcotic pain medications are used for pain control.  Narcotic pain medications can result in constipation, and therefore the patient is advised to use milk of magnesia at the first sign that this may become a problem.

Pediatric patients usually can be discharged the same day and usually tolerate the surgery much better than adults.  The frequently have very little postoperative discomfort.  Marlex mesh is not used in the pediatric population.

Complications

Complications can occur postoperatively and can prevent discharge of the patient.  First among these would be urinary retention.  This is more of a problem in males and occurs especially in young muscular males and in the older male population where prostate enlargement enters into the equation.  If urinary retention occurs, the patient may need to spend the night in the hospital with a bladder catheter in place.  Urinary retention usually resolves by the next morning, although in the circumstance of a very enlarged prostate, further measures may have to be taken.  It is for this reason that patients with significantly enlarged prostate glands are advised to have this condition corrected prior to anticipated hernia surgery.

Postoperative bleeding can also require observation or a return to the operating room to control.  Fortunately this is unusual.

Prolongation of spinal anesthesia can result in the necessity for overnight observation.  Again this is unusual.

Nerve entrapment symptoms can cause pain in the groin area and in the anterior and medial surface of the thigh.  If the nerve is truly entrapped by a suture, this can be a very difficult problem to deal with.  Repeated injections of local anesthetic and steroid medication may allow this complication to resolve but sometimes reoperation to divide the entrapped nerve may be necessary.

Postoperative formation of intra-abdominal adhesions with laparoscopic procedures can result in the necessity for later operation for bowel obstruction, although this is not generally manifest itself or months or years.

Infection of the prosthetic mesh as mentioned can occur, although this is very infrequent.  When the mesh becomes infected the only recourse is to remove the mesh completely and repair the hernia in another manner.  This is obviously a difficult outcome for both patient and the surgeon since repeated procedures may be required to repair this problem.

Postoperative follow-up.

Patients may return to work at their own discretion after hernia repair if their work does not involve very physical labor.  Most patients after Lichtenstein herniorrhaphy will want to take at least one or two weeks off.  Patients with very physical jobs may want to be off for a longer period of time, perhaps even 4 weeks.  Employers will often give light duty jobs in order to get the patient back to work.

Patients are usually seen for at least six weeks postoperatively until the hernia repair shows evidence of complete healing and are then discharged.  The incidence of postoperative recurrence varies between 1 and 2 percent and is somewhat dependent on the experience of the surgeon.