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Hernias & Other Lesions of the Abdominal Wall
Karen E. Deveney, MD
An external hernia is an abnormal protrusion of intra-abdominal tissue through a fascial defect in the abdominal wall. Although most hernias (75%) occur in the groin, incisional hernias represent an increasing proportion (15%-20%), with umbilical and other ventral hernias comprising the remainder. Generally, a hernial mass is composed of covering tissues (skin, subcutaneous tissues, etc), a peritoneal sac, and any contained viscera. Particularly if the neck of the sac is narrow where it emerges from the abdomen, bowel protruding into the hernia may become obstructed or strangulated. If the hernia is not repaired early, the defect may enlarge and operative repair may become more complicated. The definitive treatment of hernia is operative repair.
A reducible hernia is one in which the contents of the sac return to the abdomen spontaneously or with manual pressure when the patient is recumbent.
An irreducible (incarcerated) hernia is one whose contents cannot be returned to the abdomen, usually because they are trapped by a narrow neck. The term “incarceration” does not imply obstruction, inflammation, or ischemia of the herniated organs, though incarceration is necessary for obstruction or strangulation to occur.
Though the lumen of a segment of bowel within the hernia sac may become obstructed, there may initially be no interference with blood supply. Compromise to the blood supply of the contents of the sac (eg, omentum or intestine) results in a strangulated hernia, in which gangrene of the contents of the sac has occurred. The incidence of strangulation is higher in femoral than in inguinal hernias, but strangulation may occur in any hernia.
An uncommon and dangerous type of hernia, a Richter hernia, occurs when only part of the circumference of the bowel becomes incarcerated or strangulated in the fascial defect. A strangulated Richter hernia may spontaneously reduce and the gangrenous piece of intestine be overlooked at operation. The bowel may subsequently perforate, with resultant peritonitis.
HERNIAS OF THE GROIN
Anatomy
All groin hernias protrude through the myopectineal orifice of Fruchaud, a weakness or defect in the transversalis fascia, an aponeurosis located just outside the peritoneum. External to the transversalis fascia are found the transversus abdominis, internal oblique, and external oblique muscles, which are fleshy laterally and aponeurotic medially. Their aponeuroses form investing layers of the strong rectus abdominis muscles above the semilunar line. Below this line, the aponeurosis lies entirely in front of the muscle. Between the two vertical rectus muscles, the aponeuroses meet again to form the linea alba, which is well defined only above the umbilicus. The subcutaneous fat contains the Scarpa fascia—a misnomer, since it is only a condensation of connective tissue with no substantial strength.
In the groin, an indirect inguinal hernia results when obliteration of the processus vaginalis, the peritoneal extension accompanying the testis in its descent into the scrotum, fails to occur. The resultant hernia sac passes through the internal inguinal ring, a defect in the transversalis fascia halfway between the anterior iliac spine and the pubic tubercle. The sac is located anteromedially within the spermatic cord and may extend partway along the inguinal canal or accompany the cord out through the subcutaneous (external) inguinal ring, a defect medially in the external oblique muscle just above the pubic tubercle. A hernia that passes fully into the scrotum is known as a complete hernia. The sac and the spermatic cord are invested by the cremaster muscle, an extension of fibers of the internal oblique muscle.
Other anatomic structures of the groin that are important in understanding the formation of hernias and types of hernia repairs include the conjoined tendon, a fusion of the medial aponeurotic transversus abdominis and internal oblique muscles that passes along the inferolateral edge of the rectus abdominis muscle and attaches to the pubic tubercle. Between the pubic tubercle and the anterior iliac spine passes the inguinal (Poupart) ligament, formed by the lowermost border of the external oblique aponeurosis as it rolls on itself and thickens into a cord.
Just deep and parallel to the inguinal ligament runs the iliopubic tract, a band of connective tissue that extends from the iliopsoas fascia, crosses below the deep inguinal ring, forms the superior border of the femoral sheath, and inserts into the superior pubic ramus to form the lacunar (Gimbernat) ligament. The lacunar ligament is about 1.25 cm long and triangular in shape. The sharp, crescentic lateral border of this ligament is the unyielding noose for the strangulation of a femoral hernia.
The Cooper ligament is a strong, fibrous band that extends laterally for about 2.5 cm along the iliopectineal line on the superior aspect of the superior pubic ramus, starting at the lateral base of the lacunar ligament.
The Hesselbach triangle is bounded by the inguinal ligament, the inferior epigastric vessels, and the lateral border of the rectus muscle. A weakness or defect in the transversalis fascia, which forms the floor of this triangle, results in a direct inguinal hernia. In most direct hernias, the transversalis fascia is diffusely attenuated, though a discrete defect in the fascia may occasionally occur. This funicular type of direct inguinal hernia is more likely to become incarcerated, since it has distinct borders.
A femoral hernia passes beneath the iliopubic tract and inguinal ligament into the upper thigh. The predisposing anatomic feature for femoral hernias is a small empty space between the lacunar ligament medially and the femoral vein laterally—the femoral canal. Because its borders are distinct and unyielding, a femoral hernia has the highest risk of incarceration and strangulation of groin hernias.
Surgeons must be familiar with the pathways of the nerves and blood vessels of the inguinal region to avoid injuring them when repairing groin hernias. The iliohypogastric nerve (T12, L1) emerges from the lateral edge of the psoas muscle and travels inside the external oblique muscle, emerging medial to the external inguinal ring to innervate the suprapubic skin. The ilioinguinal nerve (L1) parallels the iliohypogastric nerve and travels on the surface of the spermatic cord to innervate the base of the penis (or mons pubis), the scrotum (or labia majora), and the medial thigh. This nerve is the most frequently injured in anterior open inguinal hernia repairs. The genitofemoral (L1, L2) and lateral femoral cutaneous nerves (L2, L3) travel on and lateral to the psoas muscle and provide sensation to the scrotum and anteromedial thigh and to the lateral thigh, respectively. These nerves are subject to injury during laparoscopic hernia repairs. The femoral nerve (L2-L4) travels from the lateral edge of the psoas and extends lateral to the femoral vessels. It can be injured during laparoscopic or femoral hernia repairs.
The external iliac artery travels along the medial aspect of the psoas muscle and beneath the inguinal ligament, giving off the inferior epigastric artery, which borders the medial aspect of the internal inguinal ring. The corresponding veins accompany the arteries. These vessels can be injured during hernia repairs of all types.
Causes
Nearly all inguinal hernias in infants, children, and young adults are indirect inguinal hernias. Although these “congenital” hernias most often present during the first year of life, the first clinical evidence of hernia may not appear until middle or old age, when increased intra-abdominal pressure and dilation of the internal inguinal ring allow abdominal contents to enter the previously empty peritoneal diverticulum. An untreated indirect hernia will inevitably dilate the internal ring and displace or attenuate the inguinal floor. The peritoneum may protrude on either side of the inferior epigastric vessels to give a combined direct and indirect hernia, called a pantaloon hernia.
In contrast, direct inguinal hernias are acquired as the result of a developed weakness of the transversalis fascia in the Hesselbach area. There is some evidence that direct inguinal hernias may be related to hereditary or acquired defects in collagen synthesis or turnover. Femoral hernias involve an acquired protrusion of a peritoneal sac through the femoral ring. In women, the ring may become dilated by physical and biochemical changes during pregnancy.
Any condition that chronically increases intra-abdominal pressure may contribute to the appearance and progression of a hernia. Marked obesity, abdominal strain from heavy exercise or lifting, cough, constipation with straining at stool, and prostatism with straining on micturition are often implicated. Cirrhosis with ascites, pregnancy, chronic ambulatory peritoneal dialysis, and chronically enlarged pelvic organs or pelvic tumors may also contribute. Loss of tissue turgor in the Hesselbach area, associated with a weakening of the transversalis fascia, occurs with advancing age and in chronic debilitating disease.
INDIRECT & DIRECT INGUINAL HERNIAS
Clinical Findings
Most hernias produce no symptoms until the patient notices a lump or swelling in the groin, though some patients may describe a sudden pain and bulge that occurred while lifting or straining. Frequently, hernias are detected in the course of routine physical examinations such as preemployment examinations. Some patients complain of a dragging sensation and, particularly with indirect inguinal hernias, radiation of pain into the scrotum. As a hernia enlarges, it is likely to produce a sense of discomfort or aching pain, and the patient must lie down to reduce the hernia.
In general, direct hernias produce fewer symptoms than indirect inguinal hernias and are less likely to become incarcerated or strangulated.
Examination of the groin reveals a mass that may or may not be reducible. The patient should be examined both supine and standing and also with coughing and straining, since small hernias may be difficult to demonstrate. The external ring can be identified by invaginating the scrotum and palpating with the index finger just above and lateral to the pubic tubercle (Figure 32–1). If the external ring is very small, the examiner’s finger may not enter the inguinal canal, and it may be difficult to be sure that a pulsation felt on coughing is truly a hernia. At the other extreme, a widely patent external ring does not by itself constitute hernia. Tissue must be felt protruding into the inguinal canal during coughing in order for a hernia to be diagnosed.
Figure 32–1. Insertion of finger through upper scrotum into the external inguinal ring.
Differentiating between direct and indirect inguinal hernia on examination is difficult and is of little importance, since most groin hernias should be repaired regardless of type. Nevertheless, each type of inguinal hernia has specific features more common to it. A hernia that descends into the scrotum is almost certainly indirect. On inspection with the patient erect and straining, a direct hernia more commonly appears as a symmetric, circular swelling at the external ring; the swelling disappears when the patient lies down. An indirect hernia appears as an elliptic swelling that may not reduce easily.
On palpation, the posterior wall of the inguinal canal is firm and resistant in an indirect hernia but relaxed or absent in a direct hernia. If the patient is asked to cough or strain while the examining finger is directed laterally and upward into the inguinal canal, a direct hernia protrudes against the side of the finger, whereas an indirect hernia is felt at the tip of the finger.
Compression over the internal ring when the patient strains may also help to differentiate between indirect and direct hernias. A direct hernia bulges forward through Hesselbach triangle, but the opposite hand can maintain reduction of an indirect hernia at the internal ring.
These distinctions are obscured as a hernia enlarges and distorts the anatomic relationships of the inguinal rings and canal. In most patients, the type of inguinal hernia cannot be established accurately before surgery.
Differential Diagnosis
Groin pain of musculoskeletal or obscure origin occurs primarily with vigorous physical exertion (so-called “sports hernia”) and may be difficult to distinguish from a true hernia, even with thorough physical examination. MRI may be helpful in identifying the problem as inflammation, edema, or a muscle or tendon tear or strain.
Herniation of preperitoneal fat through the inguinal ring into the spermatic cord (lipoma of the cord) is commonly misinterpreted as a hernia sac. Its true nature may only be confirmed at operation. Occasionally, a femoral hernia that has extended above the inguinal ligament after passing through the fossa ovalis femoris may be confused with an inguinal hernia. If the examining finger is placed on the pubic tubercle, the neck of the sac of a femoral hernia lies lateral and below, while that of an inguinal hernia lies above.
Inguinal hernia must be differentiated from hydrocele of the spermatic cord, lymphadenopathy or abscesses of the groin, varicocele, and residual hematoma following trauma or spontaneous hemorrhage in patients taking anticoagulants. An undescended testis in the inguinal canal must also be considered when the testis cannot be felt in the scrotum.
The presence of an impulse in the mass with coughing, bowel sounds in the mass, and failure to transilluminate are features that indicate that an irreducible mass in the groin is a hernia.
Treatment
Although inguinal hernias have traditionally been repaired electively to avoid the risks of incarceration, obstruction, and strangulation, asymptomatic or mildly symptomatic hernias may be safely observed in elderly, sedentary patients or those with high morbidity for operation. The annual risk of hernia incarceration is not precisely known but has been estimated at fewer than 2/1000 patients per year. However, a high percentage of patients become symptomatic while being observed expectantly. All symptomatic groin hernias should be repaired if the patient can tolerate surgery.
Even elderly patients tolerate elective repair of a groin hernia very well when other medical problems are optimally controlled and local anesthetic is used. Emergency operation carries a much greater risk for the elderly than carefully planned elective operation.
If the patient has significant prostatic hyperplasia, it is prudent to solve this problem first, since the risks of urinary retention and urinary tract infection are high following hernia repair in patients with significant prostatic obstruction.
Although most direct hernias do not carry as high a risk of incarceration as indirect hernias, the difficulty in reliably differentiating them from indirect hernias makes the repair of all symptomatic inguinal hernias advisable. Direct hernias of the funicular type, which are particularly likely to incarcerate, should always be repaired.
Because of the possibility of strangulation, an incarcerated, painful, or tender hernia usually requires an emergency operation. Nonoperative reduction of an incarcerated hernia may first be attempted. The patient is placed with hips elevated and given analgesics and sedation sufficient to promote muscle relaxation. Repair of the hernia may be deferred if the hernia mass reduces with gentle manipulation and if there is no clinical evidence of strangulated bowel. Though strangulation is usually clinically evident, gangrenous tissue can occasionally be reduced into the abdomen by manual or spontaneous reduction. It is therefore safest to repair the reduced hernia at the earliest opportunity. At surgery, one must decide whether to explore the abdomen to make certain that the intestine is viable. If the patient has leukocytosis or clinical signs of peritonitis or if the hernia sac contains dark or bloody fluid, the abdomen should be explored.
Figure 32–2. Indirect inguinal hernia. Inguinal canal opened, showing spermatic cord retracted medially and indirect hernia peritoneal sac dissected free to above the level of the internal inguinal ring.
Figure 32–3. Direct inguinal hernia. Inguinal canal opened and spermatic cord retracted inferiorly and laterally to reveal the hernia bulging through the floor of the Hesselbach triangle.
If recurrence is due to an overlooked indirect sac, the posterior wall is often solid and removal of the sac may be all that is required. Occasionally, a recurrence is discovered to consist of a small, sharply circumscribed defect in the previous hernioplasty, in which case closure of the defect suffices.
The goal of all hernia repairs is to reduce the contents of the hernia into the abdomen and to close the fascial defect in the inguinal floor. Traditional repairs approximated native tissues using permanent sutures. More recently, synthetic mesh has supplanted tissue repairs because multiple prospective, randomized studies have shown lower recurrence with tension-free mesh repairs than traditional primary tissue repair.
Over the past 20 years, increased experience has been gained with minimally invasive techniques for hernia repair. Laparoscopic approaches offer less pain and more rapid return to work or normal activities. Multiple randomized trials have compared open and laparoscopic hernia repairs. Although details of specific studies vary, long-term recurrence rates of open and laparoscopic repairs are similar. The success of laparoscopic approaches is dependent on experience of the surgeon, as is also true for open repair.
Although repairs today overwhelmingly employ prosthetic material, the presence of infection or need to resect gangrenous bowel may make use of nonbiologic mesh unwise. In these situations, primary tissue repairs may still be a preferable option. For this reason, surgeons need to know the traditional techniques even though they are rarely used today.
Among the traditional autologous tissue repairs, the Bassini repair is the most widely used method. In this repair, the conjoined tendon is approximated to the Poupart ligament, and the spermatic cord remains in its normal anatomic position under the external oblique aponeurosis. The Halsted repair places the external oblique beneath the cord but otherwise resembles the Bassini repair. Cooper ligament (Lotheissen–McVay) repair brings the conjoined tendon farther posteriorly and inferiorly to the Cooper ligament. Unlike the Bassini and Halsted methods, McVay repair is effective for femoral hernia but always requires a relaxing incision to relieve tension. Recurrence rates after these open nonmesh repairs vary widely according to skill and experience of the surgeon but population studies show them to range from as low as 5%-10% to as high as 33%. Though the Shouldice repair has a lower reported recurrence rate, it is not widely used, perhaps because of the more extensive dissection required and a belief that the skill of the surgeons may be as important as the method itself. In the Shouldice repair, the transversalis fascia is first divided and then imbricated to the Poupart ligament. Finally, the conjoined tendon and internal oblique muscle are also approximated in layers to the inguinal ligament.
The open preperitoneal approach exposes the groin from between the transversalis fascia and peritoneum via a lower abdominal incision to effect closure of the fascial defect. Because it requires more initial dissection and is associated with higher morbidity and recurrence rates in less experienced hands, it has not been widely used. For recurrent or large bilateral hernias, a preperitoneal approach using a large piece of mesh to span all areas of potential herniation has been described by Stoppa.
A desire to decrease the recurrence rate of hernias prompted the increased use of prosthetic materials in repair of both recurrent and first-time hernias. Methods include “plugs” of mesh inserted into the internal ring and sheets of mesh to create a tension-free repair. The most widely used technique is that of Lichtenstein, an open mesh repair that allows an early return to normal activities and a low complication and recurrence rate.
Virtually all laparoscopic approaches utilize mesh in the repair. Several methods have been explored, with two methods having emerged as most frequently employed—the transabdominal preperitoneal mesh technique (TAPP) and total extraperitoneal (preperitoneal) mesh placement (TEP). The high incidence of complications that occurred in early studies prompted revisions in the operative technique to avoid injury to lateral nerves. Several prospective randomized trials have subsequently been conducted comparing open with minimally invasive techniques and one type of minimally invasive technique with another. These studies have reported decreased pain and faster return to work with the minimally invasive techniques but increased operative time and cost. Laparoscopic procedures also require general anesthesia and therefore are not appropriate for all patients. Long-term hernia recurrence is equivalent with open and laparoscopic mesh repairs at approximately 4%. Specific situations in which laparoscopic procedures often lower recurrence include the repair of recurrent hernias after anterior open repairs, repair of bilateral hernias simultaneously, and repair in patients who must return to work particularly quickly. Although the percentage of hernias repaired laparoscopically has increased, its use varies considerably across different locales and still represents a minority of groin hernia repairs. The success of both open and laparoscopic repair of groin hernias is highly dependent upon the surgeon’s skill and experience with the technique.
The surgeon is occasionally called upon to prescribe a truss when a patient refuses operative repair or when there are absolute contraindications to operation. A truss should be fitted to provide adequate external compression over the defect in the abdominal wall. It should be taken off at night and put on in the morning before the patient arises. The use of a truss does not preclude later repair of a hernia, although it may cause fibrosis of the anatomic structures, so that subsequent repair may be more difficult.
Preoperative & Postoperative Course
Although groin hernia repair is usually an outpatient procedure, a thorough preoperative evaluation should be completed before the day of surgery. The anesthetic may be general, spinal, or local. Local anesthetic is effective for most patients, and the incidence of urinary retention and pulmonary complications is lowest with local anesthesia. Recurrent hernias are more easily repaired with the patient under spinal or general anesthesia, since local anesthetic does not readily diffuse through scar tissue. A sedentary worker may return to work within a few days; heavy manual labor has traditionally not been performed for up to 4-6 weeks after hernia repair, though recent studies document no increase in recurrence when full activity is resumed as early as 2 weeks after surgery, particularly when mesh has been used in the repair.
Prognosis
In addition to chronic cough, prostatism, and constipation, poor tissue quality and poor operative technique may contribute to recurrence of inguinal hernia. Because tissue is often more attenuated in direct hernias, recurrence rates are slightly higher than for indirect hernias. Placing the repair under tension leads to recurrence. Failure to find an indirect hernia, to dissect the sac high enough, or to adequately close the internal ring may lead to recurrence of indirect hernia. Postoperative wound infection is associated with increased recurrence. The recurrence rate is considerably increased in patients receiving chronic peritoneal dialysis, cirrhotics with ascites, smokers, and patients on steroids or who are malnourished.
The current recurrence rate after hernia repair in adults is reported at best to be 4%. Reasons for recurrence include failure to identify a femoral or indirect hernia.
An underappreciated sequela of groin hernia repair is chronic groin pain, which may occur in as high as 10% of patients and is usually attributed to nerve entrapment or neuroma. Laparoscopic repair or prophylactic division of the ileoinguinal nerve in open repairs has been shown to decrease the incidence of chronic groin pain.
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Eker H et al: Randomized clinical trial of total extraperitoneal inguinal hernioplasty vs Lichtenstein repair. Arch Surg 2012;147:256-260.
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Gass M et al: Bilateral total extraperitoneal inguinal hernia repair (TEP) has outcomes similar to those for unilateral TEP: population-based analysis of prospective data of 6,505 patients. Surg Endosc2012;26:1364-1368.
Hallén M et al: Laparoscopic extraperitoneal inguinal hernia repair versus open mesh repair: long-term follow-up of a randomized controlled trial. Surgery 2008;143:313-317.
Itani K et al: Management of recurrent inguinal hernias. J Am Coll Surg 2009;209:653-658.
Matthews RD et al: Inguinal hernia in the 21st century: an evidence-based review. Curr Probl Surg 2008;45:261-312.
Mizrahi H et al: Management of asymptomatic inguinal hernia. Arch Surg 2012;147:277-281.
Nam A et al: Management and therapy for sports hernia. J Am Coll Surg 2008;206:154-164.
O’Reilly E et al: A meta-analysis of surgical morbidity and recurrence after laparoscopic and open repair of primary unilateral inguinal hernia. Ann Surg 2012;255:846-853.
Stylianidis G et al: Management of the hernia sac in inguinal hernia repair. Brit J Surg 2010;97:415-419.
Zendejas B et al: Simulation-based mastery learning improves patient outcomes in laparoscopic inguinal hernia repair. Ann Surg 2011;254:502-511.
SLIDING INGUINAL HERNIA
A sliding inguinal hernia (Figure 32–4) is an indirect inguinal hernia in which the wall of a viscus forms a portion of the wall of the hernia sac. On the right side, the cecum is most commonly involved, and on the left side, the sigmoid colon. The development of a sliding hernia is related to the variable degree of posterior fixation of the large bowel or other sliding components (eg, bladder, ovary) and their proximity to the internal inguinal ring.
Figure 32–4. Right-sided sliding hernia seen in sagittal section. At arrow, the wall of the cecum forms a portion of the hernia sac.
Clinical Findings
Though sliding hernias have no special signs that distinguish them from other inguinal hernias, they should be suspected in any large hernia that cannot be completely reduced. Finding a segment of colon in the scrotum on contrast radiograph strongly suggests a sliding hernia. Recognition of this variation is of great importance at operation, since failure to recognize it may result in inadvertent entry into the lumen of the bowel or bladder.
Treatment
It is essential to recognize the entity at an early stage of operation. As is true of all indirect inguinal hernias, the sac will lie anteriorly, but the posterior wall of the sac will be formed by colon, bladder, or retroperitoneal ileum.
After the cord has been dissected free from the hernia sac, most sliding hernias can be reduced by a series of inverting sutures (Bevan technique) and one of the standard types of inguinal repair performed. Very large sliding hernias may have to be reduced by entering the peritoneal cavity through a separate incision (La Roque technique), pulling the bowel back into the abdomen, and fixing it to the posterior abdominal wall. The hernia is then repaired in the usual fashion. Sliding hernias can also be repaired successfully by laparoscopic (TAPP or TEP) techniques in experienced hands.
Prognosis
Sliding hernias have a higher recurrence rate than uncomplicated indirect hernias.
The surgical complication most often encountered during repair of a sliding hernia is entry into the bowel or bladder, usually due to failure to recognize that the hernia is a sliding hernia.
Adams R et al: Outcome of sliding inguinal hernia repair. Hernia 2010;14:47-49.
Freundlich R et al: Laparoscopic repair of an incarcerated right indirect sliding inguinal hernia involving a retroperitoneal ileum. Hernia 2011;15:225-227.
FEMORAL HERNIA
A femoral hernia descends through the femoral canal beneath the inguinal ligament. Because of its narrow neck, it is prone to incarceration and strangulation. Femoral hernia is much more common in women than in men, but in both sexes femoral hernia is less common than inguinal hernia. Femoral hernias comprise about one-third of groin hernias in women and about 2% of groin hernias in men.
Clinical Findings
Femoral hernias are notoriously asymptomatic until incarceration or strangulation occurs. Even with obstruction or strangulation, the patient may feel discomfort more in the abdomen than in the femoral area. Thus, colicky abdominal pain and signs of intestinal obstruction frequently are the presenting manifestations of a strangulated femoral hernia, without discomfort, pain, or tenderness in the femoral region. The patient often has a history of previous repair of an inguinal hernia, lending credence to the concept that a femoral hernia may be overlooked if a thorough search for a femoral hernia is not conducted during an operation for an inguinal hernia.
A femoral hernia may present in a variety of ways. If it is small and uncomplicated, it usually appears as a small bulge in the upper medial thigh just below the level of the inguinal ligament. Because it may be deflected anteriorly through the fossa ovalis femoris to present as a visible or palpable mass at or above the inguinal ligament, it can be confused with an inguinal hernia.
Differential Diagnosis
Femoral hernia must be distinguished from inguinal hernia, a saphenous varix, and femoral adenopathy. A saphenous varix transmits a distinct thrill when a patient coughs, and it appears and disappears instantly when the patient stands or lies down—in contrast to femoral hernias, which are either irreducible or reduce gradually on pressure.
Treatment
A femoral hernia can be repaired through an open or laparoscopic approach, with mesh or primary tissue repair. The traditional primary repair was the McVay (Cooper ligament) repair that employed a relaxing incision in the anterior rectus sheath. More recently, open repair with mesh or laparoscopic preperitoneal repair (TEP) have been used. No matter what the approach, the hernia is often difficult to reduce. Reduction may be facilitated by carefully incising the iliopubic tract, Gimbernat ligament, or even the inguinal ligament. Occasionally, a counterincision in the thigh is required to free attachments below the inguinal ligament. Irrespective of the approach used, successful femoral hernia repair must close the femoral canal.
If the hernia sac and mass reduce when the patient is given opiates or anesthesia and if bloody fluid appears in the hernia sac when it is exposed and opened, one must strongly suspect the possibility of nonviable bowel in the peritoneal cavity. In such cases, it is mandatory to explore the abdomen, an advantage of the laparoscopic approach.
Prognosis
Recurrence rates are equivalent to that of inguinal hernia at 4%-5%.
Chan G: Longterm results of a prospective study of 225 femoral hernia repairs: indications for tissue and mesh repair. J Am Coll Surg 2008;207:360-367.
Putnis S: Synchronous femoral hernias diagnosed during endoscopic inguinal hernia repair. Surg Endosc 2011;25: 3752-3754.
OTHER TYPES OF HERNIAS
UMBILICAL HERNIAS IN ADULTS
Umbilical hernia in adults occurs long after closure of the umbilical ring and is due to a gradual yielding of the cicatricial tissue closing the ring. It is more common in women than in men.
Predisposing factors include: (1) multiple pregnancies with prolonged labor, (2) ascites, (3) obesity, and (4) large intra-abdominal tumors.
Clinical Findings
In adults, umbilical hernia does not usually obliterate spontaneously, as in children, but instead increases steadily in size. The hernia sac may have multiple loculations. Umbilical hernias usually contain omentum, but small and large bowel may be present. Emergency repair is often necessary, because the neck of the hernia is usually quite narrow compared to the size of the herniated mass and incarceration and strangulation are common.
Umbilical hernias with tight rings are often associated with sharp pain on coughing or straining. Very large umbilical hernias more commonly produce a dragging or aching sensation.
Treatment
Umbilical hernia in an adult should be repaired expeditiously to avoid incarceration and strangulation. Repairs utilizing mesh result in the lowest recurrence rate. The laparoscopic approach is associated with less postoperative pain and faster recovery than open techniques. Mesh should be used for all but the smallest umbilical hernias.
The presence of cirrhosis and ascites does not contraindicate repair of an umbilical hernia, since incarceration, strangulation, and rupture are particularly dangerous in patients with these disorders. If significant ascites exists, however, it should first be controlled medically or by transjugular intrahepatic portosystemic shunt (TIPS) if necessary, since mortality, morbidity, and recurrence are higher after hernia repair in patients with ascites, when the procedure must be performed as an emergency. Preoperative correction of fluid and electrolyte imbalance and improvement of nutrition also improve the outcome in these patients.
Prognosis
Factors that lead to a high rate of complication and recurrence after surgical repair include large size of the hernia, old age or debility of the patient, obesity, and the presence of related intra-abdominal disease. In healthy individuals, surgical repair of the umbilical defects gives good results with a low rate of recurrence.
Aslani N et al: Does mesh offer an advantage over tissue in the open repair of umbilical hernias? A systematic review and meta-analysis. Hernia 2010;14:455-462.
Farrow B et al: More than 150 consecutive open umbilical hernia repairs in a major Veterans Administration Medical Center. Am J Surg 2008;196:647-651.
Gray S et al: Umbilical herniorrhapy in cirrhosis: improved outcomes with elective repair. J Gastrointest Surg 2008;12: 675-681.
McKay A et al: Umbilical hernia repair in the presence of cirrhosis and ascites: results of a survey and review of the literature. Hernia 2009;13:461-468.
EPIGASTRIC HERNIA
An epigastric hernia (Figure 32–5) protrudes through the linea alba above the level of the umbilicus. The hernia may develop through one of the foramina of egress of the small paramidline nerves and vessels or through an area of congenital weakness in the linea alba.
Figure 32–5. Epigastric hernia. Note closeness to midline and the presence in upper abdomen. The herniation is through the linea alba.
About 3%-5% of the population have epigastric hernias. They are more common in men than in women and most common between the ages of 20 and 50. About 20% of epigastric hernias are multiple, and about 80% occur just off the midline.
Clinical Findings
Most epigastric hernias are painless and are found on routine abdominal examination. If symptomatic, their presentation ranges from mild epigastric pain and tenderness to deep, burning epigastric pain with radiation to the back or the lower abdominal quadrants. The pain may be accompanied by abdominal bloating, nausea, or vomiting. The symptoms often occur after a large meal and on occasion may be relieved by reclining, probably because the supine position causes the herniated mass to drop away from the anterior abdominal wall. The smaller masses most frequently contain only preperitoneal fat and are especially prone to incarceration and strangulation. These smaller hernias are often tender. Larger hernias seldom strangulate and may contain, in addition to preperitoneal fat, a portion of the nearby omentum and, occasionally, a loop of small or large bowel.
If a mass is palpable, the diagnosis can often be confirmed by any maneuver that will increase intra-abdominal pressure and thereby cause the mass to bulge anteriorly. The diagnosis is difficult to make when the patient is obese, since a mass is hard to palpate; ultrasound, CT, or tangential radiographs may be needed in the very obese patient.
Differential Diagnosis
Differential diagnosis includes peptic ulcer, gallbladder disease, hiatal hernia, pancreatitis, and upper small bowel obstruction. On occasion, it may be impossible to distinguish the hernial mass from a subcutaneous lipoma, fibroma, or neurofibroma.
Another condition that must be distinguished from an epigastric hernia is diastasis recti, a diffuse widening and attenuation of the linea alba without a fascial defect. On examination, this condition appears as a fusiform, linear bulge between the two rectus abdominis muscles without a discrete fascial defect. Although this condition may be unsightly, repair should be avoided since there is no risk of incarceration, the fascial layer is weak, and the recurrence rate is high. If it is painful or unsightly, a diastasis is best repaired using a laparoscopic plication technique.
Treatment
Most epigastric hernias should be repaired, since small ones are likely to become incarcerated and large ones are often symptomatic and unsightly. Small defects can usually be closed primarily, although mesh should be used for large hernias. Herniated fat contents are usually dissected free and removed. Intraperitoneal herniating structures are reduced, but no attempt is made to close the peritoneal sac.
Prognosis
The recurrence rate is 10%-20%, a higher incidence than with the routine inguinal or femoral hernia repair. This high recurrence rate may be partly due to failure to recognize and repair multiple small defects.
Palanivelu C et al: Laparoscopic repair of diastasis recti using the “Venetian blinds” technique of plication with prosthetic reinforcement: a retrospective study. Hernia 2009;13:287-292.
INCISIONAL HERNIA (VENTRAL HERNIA)
About 10% of abdominal operations result in incisional hernias. The incidence of this iatrogenic type of hernia is not diminishing in spite of an awareness of the many causative factors.
Etiology
The factors most often responsible for incisional hernia are listed below. When more than one factor coexists in the same patient, the likelihood of postoperative wound failure is greatly increased.
Treatment
Small incisional hernias should be treated by early repair since they may cause bowel obstruction. If the patient is unwilling to undergo surgery or is a poor surgical risk, symptoms may be controlled by an elastic binder.
Defects too large to close easily may be left without surgical repair if they are asymptomatic, since they are less likely to incarcerate bowel than smaller defects.
For only the very smallest incisional hernias (< 2 cm in diameter) should a direct fascia-to-fascia repair be considered. Interrupted or continuous closure may be used, but the sutures should be nonabsorbable. Sutures tied too tightly or tension on the repair will predispose to recurrence.
Although no specific diameter distinguishes a small from a large hernia, a hernia can be considered large when the fascial edges cannot be approximated without tension. Primary closure of a large defect is not advisable, since tension on the closure increases the risk of hernia recurrence. Increasingly, repair of large or recurrent defects is performed using nonabsorbable mesh. Although a variety of techniques exist for placement of the mesh, a retrorectus underlay achieves a lower recurrence rate than an edge-to-edge or onlay placement. If a large dead space persists, a closed drainage system is usually employed in the space above the fascia. The lowest recurrence is achieved if native tissues can be approximated over the mesh underlay.
Laparoscopic techniques are increasingly being used to repair incisional hernias and perform adhesiolysis electively. A sheet of synthetic material is secured to the abdominal wall as an underlay graft; the intraperitoneal placement of the graft enhances the durability of the repair, though it also increases the risk of bowel adhesions or fistula formation.
Alternative methods to repair very large hernias that close the fascial defect using the patient’s native tissue include component separation techniques that allow primary closure in the midline (Figure 32–6). These techniques are especially indicated when the procedure is infected or contaminated, making synthetic mesh an unwise choice. In a contaminated or infected field biologic mesh of human or animal origin is increasingly used as an underlay since infection risk is high with synthetic mesh. Best results are seen, when native tissue can be brought together over the biologic mesh.
Figure 32–6. Component separation technique to allow primary closure in the midline, usually over a mesh underlay. A. Division of the external oblique aponeurosis. B. Release of the rectus from the posterior rectus sheath. C. Closure of the rectus in the midline. D. Mesh underlay.
Prognosis
Results of randomized clinical trials show that mesh repair is superior to primary suture repair, even for small incisional hernias. Despite the increasing use of both open and laparoscopic mesh repairs, however, population-based studies show that incisional hernias continue to recur at a high rate after repair, and the recurrence rate increases with each subsequent reoperation for recurrence, reaching almost 40% on average after the third recurrence. Factors shown to increase risk of hernia recurrence include wound infection, the presence of abdominal aneurysms, smoking, and poor nutrition. Recurrence rates are so high in smokers that many surgeons require patients to stop smoking for a month before the operation. If patients are able to stop smoking, complications and recurrence are cut in half. In all techniques employing mesh, the underlay technique with at least 3-4 cm of underlay of the mesh leads to the lowest recurrence rates. In addition to a high recurrence rate after operations, complications such as infected mesh, bleeding, seroma, and erosion of mesh into bowel causing a fistula occur in a small percentage of cases. Mesh infection is more likely after repair of a hernia occurring in a wound with a previous infection.
Albright E et al: The component separation technique for hernia repair: a comparison of open and endoscopic techniques. Am Surg 2011;77:839-843.
Breuing K et al: Incisional ventral hernias: review of the literature and recommendations regarding the grading and technique of repair. Surgery 2010;148:544-558.
den Hartog D et al: Open surgical procedures for incisional hernias. Cochrane Database Syst Rev 2008 Jul 16;(3): CD006438
Itani KMF et al: Comparison of laparoscopic and open repair with mesh for the treatment of ventral incisional hernia. Arch Surg 2010;145:322-328.
Jin J et al: Laparoscopic versus open ventral hernia repair. Surg Clin N Am 2008;88:1083-1100.
Lindström D et al: Effects of a perioperative smoking cessation intervention on postoperative complications. Ann Surg 2008;248:739-745.
Melvin WS et al: Laparoscopic ventral hernia repair. World J Surg 2011;35:1496-1499.
Sauerland S et al: Laparoscopic versus open surgical techniques for ventral or incisional hernia repair. Cochrane Database of Systematic Reviews 2011 Mar 16;(3):CD007781.
PARASTOMAL HERNIA
A parastomal hernia is a particularly troublesome hernia to repair successfully, since the stoma’s course through the abdominal wall is, by its very nature, a hernia. Studies cite an incidence of up to 50% for this type of hernia. Traditional teaching advises that a stoma be placed through the rectus muscle rather than more laterally, but even perfect stoma placement can result in hernia formation when the fascial opening stretches and allows additional loops of intestine to protrude. Causes include collagen defects and anything that increases intra-abdominal pressure such as straining, heavy lifting, or obesity.
Parastomal hernias should be repaired if they interfere with stoma function or are difficult to reduce, as they can incarcerate and strangulate. If the hernia is asymptomatic or very large, repair is not mandatory. Many options for repair of a parastomal hernia are described. Primary repair and moving the stoma have particularly poor results. The lowest recurrence is found with mesh repair by open or laparoscopic approach, placing the mesh beneath the rectus or intraperitoneally in a keyhole fashion. Because of the high risk of this hernia’s occurrence, some even advocate the prophylactic use of mesh when the stoma is placed, though this practice has not gained widespread acceptance.
Israelsson L: Parastomal hernias. Surg Clin N Am 2008;88:113-125.
Tam KW: Systematic review of the use of a mesh to prevent parastomal hernia. World J Surg 2010;34:2723-2729.
VARIOUS RARE HERNIATIONS THROUGH THE ABDOMINAL WALL
Littre Hernia
A Littre hernia is a hernia that contains a Meckel diverticulum in the hernia sac. Although Littre first described the condition in relation to a femoral hernia, the relative distribution of Littre hernias is as follows—inguinal, 50%; femoral, 20%; umbilical, 20%; and miscellaneous, 10%. Littre hernias of the groin are more common in men and on the right side. The clinical findings are similar to those of Richter hernia; when strangulation is present, pain, fever, and manifestations of small bowel obstruction occur late.
Treatment consists of repair of the hernia plus, if possible, excision of the diverticulum. If acute Meckel diverticulitis is present, the acute inflammatory mass may have to be treated through a separate abdominal incision.
Amyand Hernia
An Amyand hernia is a groin hernia that contains the appendix. If the appendix is inflamed, it should be removed and the hernia repaired using native tissues or biologic mesh. If the appendix is normal and only an incidental finding in the hernia, it should be returned to the abdomen and a mesh repair employed.
Sharma H et al: Amyand’s hernia: a report of 18 consecutive patients over a 15-year period. Hernia 2007;11:31-35.
Spigelian Hernia
Spigelian hernia is an acquired ventral hernia through the linea semilunaris, the line where the sheaths of the lateral abdominal muscles fuse to form the lateral rectus sheath. Spigelian hernias are nearly always found above the level of the inferior epigastric vessels. They most commonly occur where the semicircular line (fold of Douglas) crosses the linea semilunaris.
The presenting symptom is pain that is usually localized to the hernia site and may be aggravated by any maneuver that increases intra-abdominal pressure. With time, the pain may become more dull, constant, and diffuse, making diagnosis more difficult.
If a mass can be demonstrated, the diagnosis presents little difficulty. The diagnosis is most easily made with the patient standing and straining; a bulge then presents in the lower abdominal area and disappears with a gurgling sound on pressure. Following reduction of the mass, the hernia orifice can usually be palpated.
Diagnosis is often made more difficult because the hernial defect may lie beneath an intact external oblique layer and therefore not be palpable. The hernia often dissects within the layers of the abdominal wall and may not present a distinct mass, or the mass may be located at a distance from the linea semilunaris. Patients with spigelian hernias should have a tender point over the hernia orifice, though tenderness alone is not sufficient to make the diagnosis. Both ultrasound and CT scan may help to confirm the diagnosis.
Spigelian hernias have a high incidence of incarceration and should be repaired. Small hernias may be repaired by primary aponeurotic closure though fascial defects larger than 2-3 cm should be repaired using mesh, preferable in an underlay, preperitoneal technique. Open or laparoscopic approach may be used according to the surgeon’s experience, with laparoscopy affording an advantage in allowing the evaluation and treatment of bilateral hernia.
Bittner J et al: Mesh-free laparoscopic spigelian hernia repair. Am Surg 2008;74:713-720.
Saber A et al: Laparoscopic spigelian hernia repair: the scroll technique. Am Surg 2008;74:108-112.
Lumbar or Dorsal Hernia
Lumbar or dorsal hernias (Figure 32–7) are hernias through the posterior abdominal wall at some level in the lumbar region. The most common sites (95%) are the superior (Grynfeltt) and inferior (Petit) lumbar triangles. A “lump in the flank” is the common complaint, associated with a dull, heavy, pulling feeling. With the patient erect, the presence of a reducible, often tympanitic mass in the flank usually makes the diagnosis. Incarceration and strangulation occur in about 10% of cases. Hernias in the inferior lumbar triangle are most often small and occur in young, athletic women. They present as tender masses producing backache and usually contain fat. Lumbar hernia must be differentiated from abscesses, hematomas, soft tissue tumors, renal tumors, and muscle strain.
Figure 32–7. Anatomic relationships of lumbar or dorsal hernia. On the left, lumbar or dorsal hernia into space of Grynfeltt. On the right, hernia into the Petit triangle (inferior lumbar space).
Acquired hernias may be traumatic or nontraumatic. Severe direct trauma, penetrating wounds, abscesses, and poor healing of flank incisions are the usual causes. Congenital hernias occur in infants and are usually isolated unilateral congenital defects.
Lumbar hernias increase in size and should be repaired when found. Repair is by mobilization of the nearby fascia and obliteration of the hernia defect by precise fascia-to-fascia closure. The recurrence rate is very low.
Stamatiou D et al: Lumbar hernia: surgical anatomy, embryology, and technique of repair. Am Surg 2009;75:202-207.
Obturator Hernia
Herniation through the obturator canal is more frequent in elderly women and is difficult to diagnose preoperatively. The mortality rate (13%-40%) of these hernias makes them the most lethal of all abdominal hernias. These hernias most commonly present as small bowel obstruction with cramping abdominal pain and vomiting. The hernia is rarely palpable in the groin, though a mass may be felt on pelvic or rectal examination. The most specific finding is a positive Howship–Romberg sign, in which pain extends down the medial aspect of the thigh with abduction, extension, or internal rotation of the knee. Since this sign is present in fewer than half of cases, diagnosis should be suspected in any elderly debilitated woman without previous abdominal operations who presents with a small bowel obstruction. Though diagnosis can be confirmed by CT scan, operation should not be unduly delayed if complete bowel obstruction is present.
The abdominal approach gives the best exposure; these hernias should not be repaired from the thigh approach. The Cheatle–Henry approach (retropubic) may also be used. Simple repair is most often possible, though bladder wall, pectineal muscle, peritoneum, or mesh has been used when the defect cannot be approximated primarily.
Petrie A et al: Obturator hernia: anatomy, embryology, diagnosis, and treatment. Clin Anat 2011;24:562-569.
Stamatiou D et al: Obturator hernia revisited: surgical anatomy, embryology, diagnosis, and technique of repair. Am Surg 2011;77:1147-1157.
Perineal Hernia
A perineal hernia protrudes through the muscles and fascia of the perineal floor. It may be primary but is usually acquired following perineal prostatectomy, abdominoperineal resection of the rectum, or pelvic exenteration.
These hernias present as easily reducible perineal bulges and usually are asymptomatic but may present with pain, dysuria, bowel obstruction, or perineal skin breakdown.
Repair is usually done by an abdominal approach, with an adequate fascial and muscular perineal repair. Occasionally, polypropylene (Marlex) mesh or flaps using the gracilis, rectus abdominis, or gluteus may be necessary, when the available tissues are too attenuated for adequate primary repair.
Interparietal Hernia
Interparietal hernias, in which the sac insinuates itself between the layers of the abdominal wall, are usually of an indirect inguinal type but, rarely, may be direct or ventral hernias. Although interparietal hernias are rare, it is essential to recognize them, because strangulation is common and the mass is easily mistaken for a tumor or abscess. The lesion usually can be suspected on the basis of the physical examination provided it is kept in mind. In most cases, extensive studies for intra-abdominal tumors have preceded diagnosis. A lateral film of the abdomen will usually show bowel within the layers of the abdominal wall in cases with intestinal incarceration or strangulation, and an ultrasound or CT scan may be diagnostic.
As soon as the diagnosis is established, operation should be performed, usually through the standard inguinal approach.
Sciatic Hernia
Sciatic hernia is the rarest of abdominal hernias and consists of an outpouching of intra-abdominal contents through the greater sciatic foramen. The diagnosis is made after incarceration or strangulation of the bowel occurs. The repair is usually made through the abdominal approach. The hernia sac and contents are reduced, and the weak area is closed by making a fascial flap from the superficial fascia of the piriformis muscle.
TRAUMATIC HERNIA
Abdominal wall hernias occur rarely as a direct consequence of direct blunt abdominal injury. The patient presents with abdominal pain. On examination, ecchymosis of the abdominal wall and a bulge are usually present. The existence of a hernia may not be obvious, however, and the patient may require CT scan to confirm it. Because of the high incidence of associated intra-abdominal injuries, laparotomy is usually required. The defect should be repaired primarily if possible.
CONGENITAL DEFECTS
Congenital defects of the abdominal wall other than hernias or lesions of the urachus and umbilicus are rare. The important ones involving the urachus and umbilicus are discussed in Chapter 43.
TRAUMA TO THE ABDOMINAL WALL
Rectus Sheath Hematoma
This is a rare but important entity that may follow mild trauma to the abdominal wall or may occur spontaneously in patients with disorders of coagulation, blood dyscrasia, or degenerative vascular diseases.
Abdominal pain localized to the rectus muscle is the presenting symptom. The pain may be sudden and severe in onset or slowly progressive. The key to diagnosis is the physical examination. Careful palpation will reveal a tender mass within the abdominal wall. When the patient tenses the rectus muscles by raising the head or body, the swelling becomes more tender and distinct on palpation, in contrast to an intra-abdominal mass or tenderness that disappears when the rectus muscles are contracted (Fothergill sign). In addition, there may be detectable discoloration or ecchymosis. If the physical signs are not diagnostic, ultrasound or CT scan will demonstrate the hematoma in the abdominal wall.
The condition does not commonly require operation. Coagulation abnormalities should be corrected if possible. The acute pain and discomfort usually disappear within 2-3 days, although a residual mass may persist for several weeks. Rarely bleeding persists, requiring embolization by interventional radiology.
PAIN IN THE ABDOMINAL WALL
A number of conditions are characterized by pain in the abdominal wall without a demonstrable organic lesion. Pain from a diaphragmatic, supradiaphragmatic, or spinal cord lesion may be referred to the abdomen. Herpes zoster (shingles) may present as abdominal pain, in which case it will follow a dermatomal distribution.
Scars may be sensitive or painful, particularly in the first 6 months after surgery.
Entrapment of a nerve by a nonabsorbable suture may cause persistent incisional pain, sometimes quite severe. Hyperesthesia of the skin over the involved dermatome may provide a clue to the cause. If local anesthetic nerve block relieves the pain, nerve block with alcohol or nerve excision may be performed.
In all cases of localized pain in the abdominal wall, careful search should be made for a small hernia—MRI or CT scan may be helpful to rule out a hernia.
ABDOMINAL WALL TUMORS
Tumors of the abdominal wall are not unusual, but most are benign, eg, lipomas, hemangiomas, and fibromas. Musculoaponeurotic fibromatoses (desmoid tumors), which often occur in abdominal wall scars or after parturition in women, are discussed in more detail in Chapter 44.
Endometriomas may also occur in the abdominal wall, particularly in the scars from gynecologic procedures and Caesarian sections. Most malignant tumors of the abdominal wall are metastatic. Metastases may appear by direct invasion from intra-abdominal lesions or by vascular dissemination. The sudden appearance of a sensitive nodule anywhere in the abdominal wall that is clearly not a hernia should arouse suspicion of an occult cancer, the lung and pancreas being the more likely primary sites.
MULTIPLE CHOICE QUESTIONS
*See Chapter 43 for further discussion of hernias in the pediatric age group and Chapter 21 for a discussion of internal hernias.