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Hernias and Other Groin Problems
Introduction
This chapter describes the clinical presentation and diagnosis of lumps and swellings in the groin along with specific conditions causing these problems. Other hernias of the anterior abdominal wall (ventral hernias) are considered at the end of the chapter.
Groin lumps and swellings account for about 10% of general surgical outpatient referrals. In both sexes, the most common lumps in the groin are hernias , mainly inguinal but also femoral. Both are caused by abdominal contents protruding through an abdominal wall defect. The normal testicular descent is from the abdomen to the scrotum via the inguinal canal, and this area remains vulnerable throughout life; consequently, inguinal hernias are much more common in males. If large, an inguinal hernia may present as a scrotal rather than a groin lump, but it is obvious that it arises in the groin. In the female, the uterine round ligament pursues a similar course, which explains inguinal hernias in females. The femoral canal, below the inguinal ligament, is another potential weakness and may give rise to a femoral hernia , particularly in women.
Enlarged lymph nodes caused by infection or malignancy also cause groin lumps or swellings. Less common are vascular abnormalities, such as a saphena varix or a femoral artery aneurysm . Very rarely nowadays, a psoas abscess may track down beneath the inguinal ligament to present in the groin. This used to be a common complication of spinal tuberculosis, but is now more often a result of infection tracking down from a perforation in the left colon, caused by diverticulitis or Crohn colitis.
The anatomy of the groin provides a good starting point for understanding surgical problems in this area and is explained in Fig. 32.1 .
Lumps in the Groin
Clinical Examination
Groin and scrotum must be examined to discover the anatomical origin of the swelling. Lumps in the groin are examined as lumps elsewhere but there are some special points to note:
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examine the patient both standing and lying;
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examine for the presence of a cough impulse and test the reducibility of the lump;
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demonstrate the relationship of the origin of the lump to the inguinal ligament and the pubic tubercle.
Position for Examination
The patient must first be examined whilst standing. This increases intraabdominal pressure and makes any hernia more visible. Ask the patient to cough, while palpating the lump: intraabdominal pressure transmitted through the abdominal wall causes an expansile cough impulse in a hernia. Small inguinal hernias may reduce on lying down, and a scrotal varicocoele (see Ch. 33 ) will empty.
Consistency and Reducibility
Hernias are usually soft and ‘squishy’ but the most reliable diagnostic sign is if the lump reduces when the patient lies flat or can be reduced by gentle manipulation by patient or clinician. Most inguinal hernias are at least partly reducible, although longstanding hernias gradually become irreducible because of adhesions within the sac. These are said to be incarcerated , that is, chronically irreducible. In contrast, femoral hernias are nearly always irreducible and have no cough impulse as the femoral canal is so narrow ( Table 32.1 ), a common trap for the unwary.
TABLE 32.1
Summary of Groin Lumps and Swellings and Their Clinical Features
| Disorder | Anatomical/Developmental Basis | Clinical Features |
|---|---|---|
|
Simple bulging of abdominal contents resulting from inadequate support by weak or ruptured posterior wall of inguinal canal (transversalis fascia) | Discomfort; lump usually disappears on lying down; risk of incarceration if large but low risk of strangulation |
|
Passage of abdominal contents, often including bowel, through inguinal canal towards scrotum or labium majus | Potential for incarceration and strangulation; much more common in men |
|
Abdominal contents, often including bowel, migrate into femoral canal | Rarely has a cough impulse; rarely reducible; high rate of strangulation; more common in women |
|
Inguinal nodes drain lower limb, abdominal wall below umbilicus, anal canal, scrotal skin, penis (but not testes, which drain to paraaortic and parailiac nodes) | Enlarged nodes indicate infection, lymphoma or metastases from primary lesion in drainage area |
|
Dilatation of long saphenous vein superficial to deep fascia before it enters the femoral vein | Can be mistaken for femoral hernia but empties on pressure and disappears on lying down, unlike femoral hernia; varicose veins present in the leg |
|
Dilatation of common femoral artery just below inguinal ligament | Found in patients over 65 years, mostly male; classic clinical sign is expansile pulsation; could be mistaken for femoral hernia |
|
Classically, a tuberculous abscess of lumbar vertebra tracking down inside sheath of psoas muscle; occasionally a pyogenic abscess originating within the abdomen presents via the same route | Tuberculosis presents as swelling or ‘cold abscess’ below inguinal ligament; rare nowadays but may be confused with lymph nodes; pyogenic abscess typically ‘hot’; rarely may be caused by abscess from renal stones |
A strangulated inguinal hernia can be readily diagnosed by finding an irreducible hernia in the correct anatomical position; the lump is tender and often red. Conversely, strangulated femoral hernias are usually very small and unimpressive, often no more than the size of a grape, yet have serious consequences. Strangulated hernias, particularly femoral hernias, sometimes present with abdominal pain or signs of obstruction but without localised pain in the groin. This emphasises the importance of examining the hernial orifices in every patient with an acute abdomen, and being aware of the femoral hernia trap described earlier.
Enlarged inguinal lymph nodes vary in consistency, number and size depending on the pathological cause; they are of course not reducible. A saphena varix is very soft and disappears completely on palpation or if the patient lies down, refilling when pressure is released or if the patient stands. The leg on that side nearly always has obvious varicose veins. A saphena varix also exhibits a cough impulse. Femoral artery aneurysms , however, are firm but pulsatile. These vascular conditions must be diagnosed correctly as injudicious operation could be catastrophic!
Relationship to the Inguinal Ligament
The site of the lump in relation to the inguinal ligament needs to be identified. The ligament is not visible but stretches between two palpable bony prominences, the anterior superior iliac spine laterally and the pubic tubercle medially (see Fig. 32.1A ). The pubic tubercle is higher than might be imagined from the skin contour, lying 2 to 3 cm above the groin crease. The iliac spine is easy to locate but the pubic tubercle can be difficult, especially in obese patients. It is best found by palpating along the upper border of the pubic symphysis, outwards from the midline (care is needed in the male as the spermatic cord can be tender, where it crosses the pubic tubercle).
As shown in Fig. 32.2 , inguinal hernias always originate above the inguinal ligament, whereas femoral hernias, saphena varices and femoral artery aneurysms always arise below it. Enlarged inguinal lymph nodes are usually situated below the inguinal ligament.
Direct and Indirect Inguinal Hernias ( Fig. 32.3 )
Distinguishing between direct and indirect inguinal hernias may be clinically difficult, but it is a useful exercise in eliciting clinical signs and frequently comes up in student examinations! By definition, an indirect inguinal hernia is one in which the hernial sac lies within the spermatic cord, leaving the abdomen via the deep (internal) inguinal ring to pass along the inguinal canal, exiting through the superficial (external) ring. Thus if the hernia can be completely reduced, finger pressure over the deep ring will prevent it reappearing on coughing (the deep ring is midway between the pubic symphysis and the pubic tubercle, 2.5 cm above the femoral pulse; see Fig. 32.1A ). In contrast, a direct inguinal hernia leaves the abdomen through a weakness or split in the transversalis fascia , the posterior wall of the inguinal canal, emerging directly through the superficial ring, and cannot be controlled by digital pressure over the deep ring. In practice, this test is difficult and often unreliable. The patient’s age is perhaps the most useful indicator of the likely type of inguinal hernia, with indirect hernias most frequent under the age of 50 years and direct hernias more common after that age.
Inguinal and Femoral Hernias
Differentiating an inguinal from a femoral hernia may sometimes be problematic but is important, as it will determine the surgical approach and the operation performed. The key is the position of the hernia in relation to the inguinal ligament. An inguinal hernia, emerging from the superficial ring, has its origin above the inguinal ligament, often descending over or medial to the pubic tubercle. A femoral hernia originates below the inguinal ligament and lies lateral to the pubic tubercle. Rarely, it becomes large, and tends to be deflected upwards and may seem to arise above the inguinal ligament. This explains the importance of careful examination to determine the origin of the neck of any groin hernia.
Inguinal Hernia
Inguinal hernia is one of the most common conditions seen in general surgical clinics. In a typical district general hospital, inguinal hernias account for about 7% of surgical outpatient consultations and about 12% of operating theatre time.
As shown in Fig. 32.4 , inguinal hernias in males are by far the most common type of groin hernia. Inguinal hernias occur eight times more often in males because of the abdominal wall deficiency caused by testicular descent. Femoral hernias are rare in males, comprising only 2.5% of groin hernias. Even in females, inguinal hernias are the most frequent (twice as common as femorals). Femoral hernias are twice as common in females as in males.
Inguinal hernias occur at any age. In childhood, they always have a developmental origin and are common in premature infants. In males, hernias appear most often before the age of 5 years or after middle age. A smaller peak occurs in the late teens and early 20s. Hernias in these young men probably result from a congenital predisposition, exacerbated by work or sport. Most inguinal hernias should be repaired early to reduce the long-term risk of strangulation and the need for emergency operation. The exception is small, easily reducible painless direct hernias in elderly men or those with substantial comorbidity, where watchful waiting is a reasonable strategy.
Anatomical Considerations
The surgical anatomy of the inguinal canal is shown in Fig. 32.1C . The external oblique aponeurosis (or fascia) forms the anterior wall of the inguinal canal. In the diagram, it has been split obliquely from the external ring along the line of its fibres, for about 5 cm laterally, and the cut edges reflected upwards and downwards to expose the inguinal canal. This is how it would appear after the first stage of an inguinal hernia repair operation.
The internal oblique and transversus abdominis muscles are deficient above the medial half of the inguinal ligament, with the D-shaped defect normally filled with the transversalis fascia . Normal transversalis is particularly strong here and forms the posterior wall of the inguinal canal, providing the only restraint to herniation of the abdominal contents. Arching over this, the inferior borders of the two muscles fuse to form the conjoint musculature and ‘tendon’, which extends from the lateral half of the inguinal ligament to the pubic crest.
The spermatic cord passes through the deep ring, a defect in the transversalis fascia at the most lateral part of the muscular defect. The inferior epigastric artery passes upwards from the external iliac immediately medial to it. Thus the deep (internal) ring is bounded by the inguinal ligament below, conjoint musculature above and laterally, and the inferior epigastric artery medially. At operation, its relationship to the inferior epigastric artery defines whether an inguinal hernia is direct or indirect.
Mechanisms of Inguinal Hernia Formation
Inguinal herniation may be direct or indirect. In either case, the herniated abdominal contents are contained within a sac of peritoneum. In an indirect hernia , the peritoneal sac may represent a patent or reopened processus vaginalis and may extend as far as the tunica vaginalis and surround the testis.
Direct hernias tend to bulge forwards and rarely enter the scrotum. They are usually found in older patients with deficient muscles and weak transversalis fascia. The neck of a direct sac is broad, in contrast to the narrow neck of an indirect sac, confined as it is by the borders of the deep ring. Consequently, indirect inguinal hernias are more liable to strangulate. A direct hernia may occur suddenly after physical strain. In this case, the transversalis fascia has split, causing the appearance of a ‘rupture’.
An indirect and a direct hernia can occur together on the same side—a pantaloon hernia . A hernia may consist merely of peritoneum and associated extraperitoneal fat, but if larger, the sac usually contains omentum or small bowel, or less commonly large bowel or appendix. Occasionally, the contents of the sac are diseased, for example, large bowel carcinoma, an inflamed appendix (acute appendicitis) or peritoneal tumour metastases. Sometimes, a retroperitoneal viscus ‘slides’ down the posterior abdominal wall and herniates directly (occasionally indirectly) into the inguinal canal, dragging its overlying peritoneum with it. Thus the visceral contents of a sliding hernia lie behind and outside the peritoneal sac ( Fig. 32.5 ). This most commonly occurs in the left groin involving the descending and sigmoid colon or in larger direct hernias, may involve the bladder.
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