What is a hernia?

Causes and Symptoms

A hernia condition exists when either tissues from, or actual portions of, vital internal organs protrude beyond the enclosure of the abdomen as a result of an abnormal opening in several possible areas of the abdominal wall. In most hernias, the protruding material remains encased in the tissue of the peritoneum. This saclike extension forces itself into whatever space can be ceded by neighboring tissues outside the abdomen. Because of the swelling effect produced, the hernia is usually visible as a lump on the surface of the body. As there are several types of hernias that may occur in different areas of the abdomen, the place of noticeable swelling and the internal organs affected may vary. With the single exception of the pancreas, hernia cases have been recorded involving all other organs contained in the abdomen. The most common hernial protrusions, however, involve the small intestine and/or the omenta, folds of the peritoneum. Another category of hernia, referred to as hernia adipose, consists of a protrusion of peritoneal fat beyond the abdominal wall.

Generally speaking, the cause of hernial conditions involves not only an internal pressure pushing portions of the viscera against the abdominal wall (hence the danger of bringing on a hernia through heavy physical exertion in work or athletics) but also a point of weakness in the abdominal wall itself. Two such points of potential weakness exist in all normal, healthy individuals: the original umbilical ring, which should normally “heal” over after the umbilical cord is severed; and the groin tissues in the lower portion of the abdomen—the region where the most common hernia, the inguinal hernia, occurs. Another possible source of vulnerability to hernia protrusions is connected to the individual’s prior surgical history: Scar tissue may prove to be the weakest point of resistance to pressures originating anywhere in the abdominal region.

It should be noted that, because the abdominal tissues of infants and young children are particularly delicate, there is a proportionately higher occurrence of hernial conditions among babies and toddlers. If the hernia is diagnosed and treated early enough, complete healing is almost certain in such cases, most of which do not develop beyond the preliminary, or reducible, stage.

The several stages, or degrees, of hernial development usually begin with what doctors call a reducible hernia condition. At this stage, a patient suffering from hernia, sensing the onset of the disorder, may be able to obtain temporary relief from a developing protrusion by changing posture angle when upright or by lying down. Until the late twentieth century, some physicians preferred to treat reducible hernias by means of an externally attached pressure device, or truss, rather than resorting to surgical intervention. This form of treatment was gradually dropped in favor of increasingly effective hernioplasty operations.

When a hernial condition enters what is called the stage of incarceration, the advanced protrusion of the sac containing portions of viscera through the opening, or ring, in the abdominal wall can cause very severe complications. If, as is frequently the case, the protruding hernia sac passes through the ring as a fingerlike tube and then assumes a globular form outside the abdominal wall, a state of incarceration exists. As this state advances, the patient runs the risk of hernial strangulation. The constricting pressure of the ring’s edges on the hernial sac interferes with circulatory functions in the herniated organ, causing destruction of tissues and, unless surgical intervention occurs, rapid spread of gangrene throughout the affected organ. The sixteenth-century French surgeon Pierre Franco carried out the first operation to release a strangulated hernia by inserting a thin instrument between the incarcerated bowel and the herniated sac, then incising the latter without touching the extruded vital organ.

A surprisingly wide range of hernial conditions have been noted and studied. These include hernias in the umbilical, epigastric (upper abdominal), spigelian (transversus abdominal muscle), interparietal, and groin regions. Hernias in the groin can be either femoral or inguinal. Inguinal hernias affecting the groin area have always been by far the most common, accounting for more than three-quarters of hernial cases, particularly among males.

Inguinal hernias
share a number of common characteristics with one another and with the other closely associated form of groin hernia, the femoral hernia. Inguinal hernias are all caused by the abnormal introduction of a hernial sac into one of the four-centimeter-long inguinal canals located on the sides of the abdomen. These canals originate in the lower portion of the abdomen at an aperture called the inguinal ring. They have an external exit point in the rectus abdominal tissue. Located inside each inguinal canal are the ilioinguinal nerve, the genital branch of the genitofemoral nerve, and the spermatic cord. A comparable passageway from the abdomen into the groin area is found at the femoral ring, through which both the femoral artery and the femoral vein pass.

It may take a long period, sometimes years, for the sac to engage itself fully in the inguinal or femoral ring. Once the ring is passed, however, pressures from inside the abdomen help it descend through the canal rather quickly. If the external inguinal ring is firm in structure, and particularly if the narrow passageway is largely filled with the thickness of the spermatic cord, the inguinal hernia may be partially arrested at this point. In men, once it passes beyond the external inguinal ring, however, it quickly descends into the scrotum. In women, the inguinal canal contains the round ligament, which may also temporarily impede the further descent of the hernial sac beyond the external inguinal opening.

Treatment and Therapy

Given the widespread occurrence of hernia conditions, especially inguinal hernias, at all age levels in most societies, physicians receive extensive training in the diagnosis and, among those with surgical training, the treatment of hernia patients. Though not always necessary, surgery to repair inguinal hernias is common (external trusses having been largely abandoned), but different schools support different surgical methods. Options include open surgery or laparoscopy, and sutures versus surgical mesh. With the exception of operations involving the insertion of prosthetic devices to block the extension of hernia damage, most modern inguinal hernioplasty methods derive from the model finalized by the Italian Edoardo Bassini in the late nineteenth century.

Bassini believed that the surgical methods of his time fell short of the goal of complete hernia repair, since most postoperational patients were required to wear a truss to guard against recurring problems. In the simplest of surgical terms, his solution involved the physiological reconstruction of the inguinal canal. The operation provided for a new internal passageway to an external opening, as well as strengthened anterior and posterior inguinal walls. After initial incisions and ligation of the hernial sac, Bassini’s method involved a separation of tissues between the internal inguinal ring and the pubis. A tissue section referred to as the “triple layer” (containing the internal oblique, the transversus abdominal, and the transversalis fascia tissue layers) was then attached by a line of sutures to the Poupart ligament, with a lowermost suture at the edge of the rectus abdominal muscle. Such local reconstruction of the inguinal canal proved to strengthen the entire zone against the recurrence of ruptures.

Physicians operating on indirect, as opposed to direct, inguinal hernias confront a relatively uncomplicated set of procedures. In the former case, a high ligation of the peritoneal sac (a circular incision of the peritoneum at a point well inside the abdominal inguinal ring) usually makes it possible to remove the sac entirely. Complications can occur if the patient is obese, since a large mass of peritoneal fatty material may be joined to the sac, obstructing access to the inguinal ring. For normal indirect inguinal hernias, the next basic step, after ensuring that no damage has occurred to the viscera either during formation of the hernia or in the process of relocating the contents of the hernial sac inside the abdomen, is to use one of several surgical methods to reduce the opening of the inguinal ring to its normal size. The physician must also ensure that no damage to the posterior inguinal wall has occurred and that its essential attachment to Cooper’s ligament does not require additional surgical attention.

One must contrast the relative simplicity of indirect inguinal hernia surgery to treatment of direct inguinal hernias. In these cases, the hernia does not protrude through the existing inguinal aperture, but, as a result of a weakening of local tissues, passes directly through the posterior inguinal wall. The direct inguinal hernia is usually characterized by a broad base at the point of protrusion and a relatively short hernial sac. When a physician recommends surgical treatment of such hernias, the surgeon must be prepared for the extensive task of surgical reconstruction of the posterior inguinal wall as part of the operation.

Two additional reasons tend to discourage an immediate decision to operate on direct inguinal hernias. First, this form of hernia rarely strangulates the affected viscera, since the aperture stretches to allow protrusion of the hernial sac. Second, once physicians find obvious symptoms of a direct inguinal hernia (a ceding of the weakened posterior inguinal wall to pressures originating in the abdomen), they may decide to examine the patient more thoroughly to determine whether the cause behind the symptoms demands treatment as well. Such causes of abdominal pressures may range from the effects of a chronic cough to much more serious problems, including inflammation of the prostate gland or other forms of obstruction in the colon itself.

Perspective and Prospects

Because the phenomenon of hernias has been the subject of scientific observation since the onset of formal medical writing itself, a stage-by-stage development of procedures has been associated with this condition. A main dividing line appears between the mid-eighteenth and mid-nineteenth centuries, however, between the extremely rudimentary surgical treatments of the late Middle Ages and Renaissance and what can be called modern procedures.

The surgical contribution of the sixteenth-century Frenchman Pierre Franco, who performed the first operation to release an incarcerated hernia, must be considered a landmark. The major general cause for advancement in knowledge of hernias, however, is tied to the birth of a new era in medical science, characterized by the use, from about 1750 onward, of anatomical dissection to investigate the essential characteristics of a number of common diseases.

Before the relatively long line of contributions that led to general adoption of the Bassini technique of operating on hernias, surgeons tended to follow the so-called Langenbeck method, named after the German physician who pioneered modern hernioplasty. This method held that simple removal of a hernial sac at the point of its protrusion from the abdomen and closing the external aperture would lead to a closing of the sac by “adhesive inflammation.” Such spontaneous closing occurs when a severed artery “recedes” to the first branching-off point.

It took contributions by at least two lesser-known late nineteenth-century forerunners to Edoardo Bassini to convince the surgical world that hernia operations must involve a high incision of the hernial sac. Both the American H. O. Marcy (1837–1924) and the Frenchman Just Marie Marcellin Lucas-Championnière (1843–1913) have been recognized for their insistence on the necessity of high-incision operations. Their hernia operations, by incising the external oblique fascia, were the first to penetrate well beyond the external ring to expose the entire hernial sac. Following removal of the sac, it was then possible for surgeons to close the transversalis fascia and to repair the higher interior tissues that might have been damaged by the swollen hernia.

Following initial acceptance of the technique of high-incision hernial operations, a number of physicians recommended a variety of methods that might be used to repair internal tissue damage. These methods ranged from simple ligation of the sac at the internal ring, without more extensive surgery involving either the abdominal wall or the spermatic cord, to the much more extensive method practiced by Bassini. Even after the Bassini method succeeded in gaining almost universal recognition, other adaptations (but nothing that represented a full innovation) would be added during the middle decades of the twentieth century. One such method, which borrowed from the German physician Georg Lotheissen’s use of Cooper’s ligament to serve as a foundation for suturing damaged layers of lower abdominal tissues, came to be called the McVay method, after its chief proponent, the American Chester McVay.

Perhaps the most common approach to uncomplicated inguinal hernia repair in the early twenty-first century is the emplacement of synthetic mesh via a laparoscopic procedure, which, like all laparoscopy, has the advantage of greatly reducing recovery times. The most recent developments in this area include the use of biologic mesh, or biomesh, made of human or animal tissue that is fully absorbable by the human body. Studies of this procedure are ongoing, but show promise for reducing the incidence of postsurgical complications.

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