Abdominal wall and hernia

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CHAPTER 12 Abdominal wall and hernia

Herniae 195

Other conditions of the abdominal wall 202

Swellings in the groin and scrotum 203

Herniae

A hernia is an abnormal protrusion of a viscus or part of a viscus through an opening in the cavity in which it is normally contained. About 75% of all herniae occur at the groin.

Classification of hernia

Congenital

A congenital hernia develops in a peritoneal sac, which gives rise to a hernia in infancy, or provides a potential channel for one to form in later life, e.g. patent processus vaginalis in indirect inguinal hernia, or failure of closure of the umbilicus orifice in umbilical hernia. These sacs represent persistent embryological channels.

Acquired

Aetiological factors

• Loss of tissue strength and elasticity, e.g. direct inguinal hernia in the older patient

• Surgical trauma, e.g. incisional hernia

• Enlargement of a foramen, e.g. enlarged oesophageal hiatus allowing development of a hiatus hernia

• Nerve damage with consequent weakening of muscles, e.g. development of inguinal hernia after appendicectomy owing to damage to the ilioinguinal nerve.

If a potential weakness is present, then the following factors may predispose to hernia formation by increasing intra-abdominal pressure. These include:

• Heavy lifting or carrying

• Coughing, e.g. asthma, COPD

• Constipation

• Benign prostatic hypertrophy

• Pregnancy

• Obesity

• Ascites

• CAPD – may unmask persistent processus vaginalis with CAPD fluid filling a potential hernial sac and presenting as scrotal oedema.

Types of hernia

Inguinal hernia

This is the most common form of hernia. There are two types: indirect and direct.

Indirect

A peritoneal sac protrudes through the deep inguinal ring, passes down the inguinal canal, and may extend as far as the upper pole of the testis. The defect is congenital and is due to a persistent processus vaginalis. It is more common in males. It may appear in infancy or early adult life. In infants, there is often an associated hydrocele and undescended testis.

Direct

This is acquired. The defect occurs in the abdominal wall, in Hesselbach’s triangle (bounded by the inguinal ligament inferiorly, the inferior epigastric artery laterally and the lateral border of rectus muscle medially). It is due to a weakness of the transversalis fascia in the posterior wall of the inguinal canal. It is often bilateral and occurs in the older patient and may be associated with obesity, cough, constipation, prostatism.

Both types may occur and straddle the inferior epigastric artery, the so-called ‘pantaloon’ hernia.

Symptoms and signs

Often none. Occasionally aching or dragging sensation in the groin. Some patients relate the development of the hernia to an episode of straining or lifting. Some patients can push the hernia back. A painful, tense, tender lump that will not reduce indicates incipient strangulation until proved otherwise. Examine the patient standing. A hernia that descends into the scrotum is likely to be indirect. A diffuse bulge medially over the canal is likely to be direct. Locate the pubic tubercle. If the hernia is above and medial to this it is an inguinal hernia, if it is below and lateral, it is a femoral hernia. Test for a cough impulse. Lay the patient down and reduce the hernia. Apply pressure over the deep inguinal ring, i.e. 1 cm above the midpoint of the inguinal ligament. Ask the patient to cough. If the hernia appears medial to the point of pressure, it is likely to be direct. If no hernia appears, release the pressure and again get the patient to cough. If it appears, it is likely to be indirect. For smaller herniae it is possible to distinguish between direct and indirect by invaginating the scrotum with the little finger into the inguinal canal. Get the patient to cough. If the hernia is indirect, the impulse hits the tip of the finger; if direct, it hits the pulp. The difference, in fact, is academic since both will be carefully looked for at surgery.

Treatment

Uncomplicated

Elective herniotomy (i.e. excision of sac) in children. Herniotomy and herniorrhaphy (repair of the defect) in adults. There are three accepted methods of repair of inguinal hernia:

1. Lichtenstein repair – this is a tension-free mesh repair using polypropylene mesh.

2. Shouldice repair – this is a double-breasted repair of the transversalis fascia followed by suturing of the conjoint tendon to the inguinal ligament with non-absorbable sutures.

3. Laparoscopic – this may be via an extraperitoneal or intraperitoneal technique. NICE guidelines recommend this technique for bilateral or recurrent inguinal herniae.

Trusses may be used if surgery is contraindicated. A spring-loaded pad is applied to the defect after the hernia has been reduced. The patient should apply it after lying down and reducing the hernia. They are uncomfortable and unhygienic. Indications for a truss are rare.

Obstructed and strangulated herniae

These require emergency surgery, with resection of bowel if necessary followed by surgical repair.

Procedure

Repair of inguinal hernia

• Make an incision 2.5 cm above and parallel to the medial ⅔ of the inguinal ligament.

• Divide the superficial fascia (Camper’s and Scarpa’s) ligating the superficial veins (superficial epigastric vein and possibly the superficial circumflex iliac vein in the lateral end of the incision.

• Expose the aponeurotic fibres of external oblique. Open the external oblique aponeurosis in the line of its fibres, extending the incision into the superficial inguinal ring.

• Dissect the ilioinguinal nerve off the spermatic cord and preserve it.

• Mobilize the cord. Check if there is a direct hernia (posterior to and separate from the cord). Carefully divide the layers of fascia covering the cord and check for an indirect sac. If indirect sac present, separate it carefully from the cord. Open the sac and reduce any contents. Twist the neck of the sac. Transfix and ligate the neck of the sac and excise redundant sac.

• Repair with Prolene mesh, attaching it to the pubic tubercle and inguinal ligament with a continuous Prolene suture and with interrupted sutures to the internal oblique and transversalis fascia, leaving an adequate opening for the cord to pass through.

• Close the external oblique with a continuous suture, making sure not to catch the ilioinguinal nerve.

• Close Scarpa’s fascia and skin.

• Exert gentle traction on the testis to make sure that it is in the base of the scrotum.

Complications

Recurrence may occur but should be less than 2%. Other complications include infection, ilioinguinal nerve entrapment, and testicular ischaemia. Testicular ischaemia is rare after initial repair but occurs with a higher incidence after repair of recurrent herniae, possibly owing to cord damage.

Femoral hernia

The defect is in the transversalis fascia overlying the femoral ring at the entry to the femoral canal. The hernia passes through the femoral canal and presents in the groin, below and lateral to the pubic tubercle. It is more common in females and carries a higher risk of strangulation. Femoral herniae are often of the Richter type.

Symptoms and signs

A lump occurs below and lateral to the pubic tubercle. It may be reducible. It may not be noticed until it becomes tender and painful. This type of hernia should be carefully sought in the obese patient who presents with signs of intestinal obstruction without an obvious cause.

Treatment

Surgical repair. An incision is made directly over the swelling. The sac is opened, the contents reduced and the sac removed. The defect is repaired by inserting non-absorbable sutures between the inguinal ligament and the pectineal ligament, thus closing the femoral canal. If the hernia is strangulated or obstructed, a separate abdominal incision will be required to deal with the bowel. There is no place for a truss in the treatment of femoral hernia – it may, in fact, be dangerous by compressing the contents of an incompletely emptied sac against the pubic bone. This is one reason why it is necessary to distinguish accurately between inguinal and femoral herniae. Recurrence rate following surgery should be less than 3%.

Procedure

Repair of femoral hernia (low approach)

• Make an incision in the line of the groin crease over the hernial sac.

• Deepen the incision to identify the hernial sac.

• Ligate superficial veins as necessary.

• Expose the sac carefully defining the neck of the sac.

• Open sac, reduce any contents.

• Transfix and ligate the neck of the sac and excise the sac.

• Repair the femoral canal by suturing the inguinal ligament to the pectineal ligament without constricting the femoral vein.

• Place the left index finger over the femoral vein, insert a stitch into the inguinal ligament and the pectineal ligament, making sure that the most lateral stitch snugly fits around the index finger.

• Withdraw the index finger, allowing the vein to fill the space.

• Alternatively, the inguinal canal may be filled with a mesh plug which is tacked in place.

• Close the wound in layers.

Umbilical hernia

This occurs in children because of incomplete closure of the umbilical orifice – most close spontaneously during the first year of life. It is more common in black children. Surgical repair should only be carried out if the hernia has not disappeared by the age of 3 and the fascial defect is >1.5 cm in diameter.

Paraumbilical hernia

It occurs just above or just below the umbilicus, and is more common in females. Predisposing factors include multiple pregnancies and obesity. The neck of the sac is usually narrow and therefore, there is a high risk of strangulation. The most common content is omentum, followed by transverse colon and small intestine. Treatment is by excision of the sac and a two-layer overlapping repair (Mayo repair).

Epigastric hernia

This is usually a small protrusion through the linea alba in the upper part of the abdomen. Often, the hernia consists of extraperitoneal fat only, but it may contain omentum or small bowel. It may be extremely painful, probably because of trapping and ischaemia of extraperitoneal fat. Treatment is by simple suture of the defect with non-absorbable sutures.

Incisional hernia

This occurs through a defect in the scar of a previous abdominal incision.

Symptoms and signs

May occur up to 5 years postoperatively. A swelling protrudes through the wound. Many are large and involve the whole incision – consequently the neck of the sac is wide and the risk of strangulation rare. If the defect is small, there is a greater risk of strangulation.

Treatment

Small herniae

These may be repaired with interrupted non-absorbable sutures.

Large herniae

These may be very unsightly and noticeable through the clothes. If the patient is unfit for surgery, a corset may be worn. Surgical repair should otherwise be undertaken. The old scar should be excised and normal rectus sheath identified. The edges may then be approximated with non-absorbable sutures. Often to get an adequate repair the hernia is repaired in two layers overlapping. Very large defects may need interposition of foreign material, e.g. polypropylene mesh. The recurrence rate is high, being 10–20%.

Richter’s hernia (→ Fig. 12.2)

Part of the circumference of the bowel becomes trapped in the defect. This is usually the antimesenteric border of the small bowel. A strangulated Richter’s hernia may reduce spontaneously leaving a segment of bowel with a gangrenous area – this may subsequently perforate with resulting peritonitis.

Figure 12.2 Richter’s hernia.

Spigelian hernia

This is a hernia through the linea semilunaris at the lateral border of the rectus sheath. It occurs at a point a hand’s breadth above the pubic symphysis at the level of the linea semicircularis (arcuate line of Douglas). This is the point at which the posterior rectus sheath becomes deficient and all aponeuroses of the abdominal muscles pass in front of the rectus muscle. Surgical repair is required.

Littre’s hernia

This is a hernia that contains a Meckel’s diverticulum in the sac.

Sliding hernia (hernia-en-glissade → Fig. 12.3)

The posterior parietal peritoneum ‘slides’ on the underlying tissue; therefore, the posterior wall of the sac is formed, not of peritoneum alone, but of sigmoid colon on the left and caecum on the right. These herniae occur in older patients, especially males with obesity and weak musculature. Diagnosis is made at surgery. Care needs to be taken when excising the sac.

Figure 12.3 Sliding hernia. Part of the bowel wall (sigmoid colon or caecum) forms the posterior wall of the sac.

Obturator hernia

This hernia occurs through the obturator foramen. It is commoner in elderly females. The diagnosis is usually made via a laparotomy for intestinal obstruction. It is difficult to feel the hernia as it occurs in the groin deep to pectineus. The hernia may cause pressure on the obturator nerve at the obturator foramen causing referred pain down the medial side of the thigh, especially if the hernia is strangulated (Howship–Romberg sign).

Lumbar herniae

These may occur through Grynfeltt’s space (below the 12th rib) or Petit’s triangle (just above the iliac crest). They usually contain extraperitoneal fat and are often mistaken for lipomas.

Internal herniae

Usually present with intestinal obstruction. They are often the result of iatrogenic causes such as defects left in the mesentery or following adhesions. Rarely, they may occur through the epiploic foramen of Winslow or into paracaecal or paraduodenal fossae.

Other conditions of the abdominal wall

Umbilicus

Discharge

Patent vitellointestinal duct

This may result in discharge of mucus or small bowel contents. It is usually associated with a Meckel’s diverticulum and usually occurs in infancy.

Patent urachus

This may not present until early adult life or even old age and results from distension of the bladder usually because of outflow obstruction. Urine discharges through the umbilicus.

Abscess in a urachal cyst

This may discharge through the umbilicus.

Infection

This may occur deep in the umbilicus and cause discharge. It may be fungal. Inflammation of the umbilicus is called omphalitis.

Umbilical calculus

This is usually black in colour and composed of inspissated desquamated epithelium and may be associated with infection and discharge. This condition is not infrequently seen in the elderly and associated with poor hygiene.

Endometriosis

The umbilicus is usually painful and bleeds at the time of menstruation.

Mass

Umbilical hernia (see above)

Secondary carcinoma

This is rare and presents as an umbilical nodule (Sister Joseph’s nodule). It may be associated with carcinoma of the stomach, colon, ovary or breast.

Rectus sheath haematoma

This is due to tearing of the inferior epigastric vessels with haematoma in the posterior rectus sheath. It may occur in athletic, muscular young men during exercise or in thin elderly females. Occasionally it occurs during pregnancy. It may be also associated with disorders of coagulation or blood dyscrasias.

Symptoms and signs

Sudden onset of severe lower abdominal pain in the left or right lower abdomen. Occasionally its onset is slow and progressive. Examination in the early stages reveals a tender mass in the abdominal wall. Later bruising may be detectable in the suprapubic area.

Treatment

This is usually conservative. The acute pain and discomfort should disappear within a few days. In young patients with a rectus sheath haematoma on the right side, the symptoms and signs may be mistaken for acute appendicitis.

Tumours of the abdominal wall

Most of these are benign lipomas. Most malignant tumours of the abdominal wall are metastatic. Musculoaponeurotic fibromatoses (desmoid tumours) may occur and are part of Gardner’s syndrome (familial polyposis coli, osteomas, sebaceous cysts and desmoid tumours).

Swellings in the groin and scrotum

These are a common clinical problem. A list of conditions is shown in Table 12.1. They are discussed further in the relevant chapters.

TABLE 12.1 Lumps in the groin and scrotum

Groin

Above the inguinal ligament:

• sebaceous cyst

• lipoma

• direct inguinal hernia

• indirect inguinal hernia

• malgaigne’s bulges (minor bilateral bulging of the inguinal canal – normal)

• imperfectly descended testis

• lipoma of the cord

• hydrocele of the cord (rare)

• hydrocele of the canal of Nuck (rare)

Below the inguinal ligament:

• femoral artery aneurysm (true or false)

• imperfectly descended testis

• neuroma of femoral nerve (rare)

• synovioma of hip joint (rare)

• obturator hernia (rare)

• psoas abscess (rare)

Scrotum

• sebaceous cyst

• indirect inguinal hernia

• hydrocele

• epididymal cyst (spermatocele)

• torsion of testicular appendage

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Abdominal wall and hernia

General description of a hernia (→ Fig. 12.1)

Richter’s hernia (→ Fig. 12.2)

Sliding hernia (hernia-en-glissade → Fig. 12.3)

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