A hernia, or “rupture,” is a defect in the abdominal wall, into which may protrude an organ or part from the abdominal cavity. The defect is most usually an actual hole in the muscle and fascial layers. The elastic lining layer of peritoneum remains unbroken and is pushed out into the defective area. This lines the hernial cavity and is called the hernial sac. The overlying skin may bulge but remains intact.
Other hernial defects are merely a weakening of the muscle layers without an actual hole but rather a thinned-out area of muscle which bulges under the strain on the abdominal wall. Others are combinations of a hole in one layer with a weakening of other muscle layers. In some cases, the sac itself may be made up of another layer besides peritoneum. But most hernial defects are an actual hole through the muscle and fascial layer with peritoneum as the lining hernial sac.
Herniae vary greatly in size. Some are very small, while others may make up the greater proportion of the abdominal wall. Regardless of their size when first perceptible, they all become progressively larger. Some progress in size very slowly, while others rapidly enlarge. But in brief, the sooner treatment is instigated the lesser its magnitude.
The cause of a hernia is often difficult to determine. Several factors are known to play a role. Direct injury to the abdomen may result in a hernia. Others are from abnormal strain on the abdominal muscles with their resultant tearing or stretching. Increased pressure within the abdomen, such as from persistent vigorous coughing, or diseases which cause fluid collections within the abdomen, or enlarging tumors, or even pregnancy, seem to precipitate some hemiae. Many are the result of imperfect formation or development of the abdominal wall, that is, defects present since birth (congenital). Still others may be the result of incomplete healing after abdominal incision. In a few the cause is remote.
Most types of herniae are of a transitory nature. They bulge when there is pressure within the abdomen but are not apparent when there is no such force. A hernia which is empty and contains no abdominal organ or part is said to be reduced. Most herniae automatically reduce when a person lies down. With standing, most will protrude again. Straining by coughing, sneezing, or lifting makes the hernia protrude even farther. Even while standing, most can be reduced by simple pressure of the hand over the bulge; but with release of the hand, the bulge reappears. The larger herniae protrude most readily and reduce most readily. A hernia through a small abdominal wall defect is more difficult to reduce but more easily held in reduction.
Incarcerated Hernia. A hernia which cannot be reduced is called an incarcerated hernia. These are often quite painful and usually demand immediate operative treatment. Incarceration is usually found in a hernia with a large sac but a small wall defect, which has allowed the protrusion of a larger volume of abdominal tissue than can be pushed back through the opening. An incarcerated hernia may also be due to the formation of adhesions or scars between the sac and the sac contents when the hernia has remained unreduced for a long period of time. Reduction of incarcerated herniae can usually be facilitated by placing the patient at bed rest and administering sedatives to relax the abdominal muscles. Occasionally an anesthetic is required. When a hernia has once become incarcerated, it should be surgically repaired, if at all possible, before it incarcerates again.
Strangulated Hernia. An incarcerated hernia which is so tight that it pinches off the blood supply of the part within it is called a strangulated hernia. This is a serious situation, for the imprisoned part becomes gangrenous. Immediate operative correction is imperative. A loop of intestine might become caught in a hernia to cause intestinal obstruction. With death of the strangulated loop there also results the formation of toxins and a leakage of the intestinal contents. Without surgical intervention this is a grave condition.
Surgical treatment of a hernia will vary according to the specific type and location, but in general certain basic principles are employed. All involved structures arc dissected free. The contents of the hernial sac are inspected and treated according to their needs. The base of the sac is closed and the excess portion cut away. The defect in the fascial and muscle layers is then repaired in separate layers. This is the most important part of the operation, of course, and each type of hernia entails a different type of reconstruction. Whenever possible, each type of tissue is united to that of the same kind and quality. Tension on the tissues is avoided. In some cases flaps of adjacent layers are rotated over the defect and grafted in place to reinforce the area. Sometimes there is not sufficient tissue of strength in the operative vicinity to reconstruct the defect, so sheaths of fascia are taken from such places as the thigh to graft into the region. With very large defects it is occasionally necessary to employ artificial materials, such as metal gauze or screen, to support the site. Every hernia is given individual evaluation as to the type of repair most efficacious, both before and during operation.
As a general rule, all herniae should be repaired as soon as practical, since they continually enlarge to make the repair a more formidable operation, and since the dangers of incarceration and strangulation are ever-present. Procrastination until a hernia becomes tremendous and disabling means not only needless suffering, but also a more complicated operation at an older age with greater operative risks.
In infants, however, treatment of slowly enlarging herniae may be deferred until the child reaches an age at which the operation will entail lesser risks. In many cases it is best to wait until the child is four or five years of age before operating, if there is no apparent discomfort and the hernia is not markedly enlarging. This decision should be left with the surgeon, but often anxious parents are not contented to accept for their child the benefits of the surgeon’s watchful waiting for the optimal time of operation.
Numerous methods have been proposed as substitutes for operative correction of abdominal wall herniae. Among these has been the truss, a supportive device to keep a hernia reduced and add artificial support to the weakened area. Innumerable types of trusses have been devised. All must be considered as only temporary measures. The truss cannot cure a hernia; it merely supports the area to keep the hernia reduced and provide relief from discomfort, as long as it is kept properly in place. The external support of a truss can hardly be expected to correct the abnormal anatomy of a hernia. However, a properly fitted truss may prevent the hernia from progressing if operative correction has to be delayed for any reason. In some cases the size of the hernia or the poor risk of an aged patient may make operation inadvisable, so the wearing of a truss may be the best means of keeping a hernia reduced and symptomless and preventing further enlargement. In the infant, special trusses are sometimes used to protect herniae until the child reaches a more ideal operative age. This may be for either the inguinal or the umbilical hernia. For the inguinal, the truss may keep the defect so sealed that the hernia will not require operation during childhood, but most often the hernia docs not seal off; and even when it does, it so often appears in later life. With the small umbilical hernia noted early in life, frequently a truss devised of adherent tape
makes operation unnecessary, if kept properly reduced for a long enough period for the area to seal itself through normal growth processes. But, for the most part, a truss cannot permanently cure any other type of hernia. Many advertisements appear in modern newspapers and magazines advising all sorts of trusses and supports for ruptures, but the only reliable agencies are those which fit trusses only on a physician’s prescription. Harm can result from poorly fitted and ill-advised trusses.
Another method proposed for the correction of herniae has been by the injection of irritating substances into the area. The theory behind this drastic method is that the inflammation so caused will resolve into scar-tissue formation which supposedly will seal over the defect and mat the layers together for support. This method is not only impractical but also unreliable and indeed dangerous. Subsequent corrective operation is more difficult or even not feasible, due to the damaging effects on the tissues of the injected chemicals. The injection method of treating herniae has long since fallen into disrepute.