Prolapse

 Partial prolapse

The mucous membrane and submucosa of the rectum protrude outside the anus for approximately 1-4 cm. When the prolapsed mucosa is palpated between the finger and thumb, it is evident that it is composed of no more than a double layer of mucous membrane (cf. complete prolapse). There is some confusion as to its exact nature. Some believe that partial rectal prolapse represents the head of a rectal intussusception, and is the early manifestation of a complete rectal prolapse. Others consider that it is a separate entity. The probable truth is that both types exist. The condition occurs most often at the extremes of life — in children between 1 and 3 years of age, and in elderly people.

In infants

The direct downward course of the rectum, due to the as yet undeveloped sacral curve (Fig. 60.9), predisposes to this con­dition, as does the reduced resting anal tone which offers diminished support to the mucosal lining of the anal canal (Mann).

In children

Partial prolapse often commences after an attack of diarrhoea, as a result of severe whooping cough, or from loss of weight and consequent diminution in the amount of fat in the ischiorectal fossae.

In adults

The condition in adults is usually associated with third-degree haemorrhoids. In the female, a torn perineum predisposes to prolapse, and in the male straining from urethral obstruction. In old age, both partial and complete prolapse are associated with atony of the sphincter mechanism but whether this is the cause of the problem or secondary to it is unknown.

Partial prolapse may follow an operation for fistula-in-ano where a large portion of muscle has been divided. Here the prolapse is usually localised to the damaged quadrant and is seldom progressive.

Prolapsed mucous membrane is pink; prolapsed internal haemorrhoids are plum coloured and more pedunculated.

Treatment

In infants and young children

Digital reposition. The parent must be taught to replace the protrusion. The distal two-thirds of the index finger is wrapped in tissue paper. The finger is inserted into the protrusion and the mass is eased into place. Gently, the finger is withdrawn, leaving the tissue paper to disintegrate. In cases of malnutrition, dietetic adjustments are necessary.

Submucous injections. If digital reposition fails after 6 weeks’ trial, injections of 5 per cent phenol in almond oil are carried out under general anaesthesia. As a result of the aseptic inflammation following these injections, the mucous membrane becomes tethered to the muscle coat.

Technique. The submucosa at the apex of the prolapse is injected circularly, so as to form a raised ring, up to 10 ml of the solution being injected. A similar injection is made at the base of the prolapse. Alternatively, if the prolapse cannot be brought down, the injections are given through a proctoscope.

Thiersch’s operation. When the prolapse persists in spite of these measures, Thiersch’s operation (below) may succeed. In infants, insertion of the little finger into the anus before the stitch is tied is recommended. In infants and young children, strong chromic catgut should be used for the stitch instead of silver wire: if wire were employed (or any other retained unabsorbable material) as growth proceeded, the stitch would have to be removed or anal stenosis would result. As the procedure is designed only as a temporary measure in the young, chromic catgut is adequate for the purpose.

In adults

Submucous injections. Submucous injections of phenol in almond oil occasionally are successful in cases of early partial prolapse.

Excision of the prolapsed mucosa. When the prolapse is unilateral the redundant mucosa can be excised after inserting and tying Goodsall’s ligature (Fig. 60.10) which, after the needles have been cut off, permits the base of the prolapsed mucous membrane to be ligated in three portions lying in juxtaposition. When necessary, the operation is combined with haemorrhoidectomy, and if the pedicle of one or more of the haemorrhoids is broad, Goodsall’s ligature is applied. Alterna­tively, an endoluminal stapling technique can now be used.

Complete prolapse

Complete prolapse (syn. procidentia) is less common than the partial variety. The protrusion consists of all layers of the rectal wall and is a descending hernia-en-glissade of the rec­tum downwards through the levator ani. As the rectum descends, it intussuscepts upon itself. The process starts with the anterior wall of the rectum where the supporting tissues are weakest, especially in women. It is more than 4 cm and commonly as much as 10—15 cm in length. On palpation between the finger and the thumb, the prolapse feels much thicker than a partial prolapse, and obviously consists of a double thickness of the entire wall of the rectum. Any prolapse over 5 cm in length contains anteriorly between its layers a pouch of peritoneum (Fig. 60.11). When large, the peritoneal pouch contains small intestine, which returns to the general peritoneal cavity with a characteristic gurgle when the prolapse is reduced. The prolapsed mucous membrane (Fig. 60.12) is often arranged in a series of circular folds. The anal sphincter is characteristically patulous and gapes widely on straining to allow the rectum to prolapse. Complete prolapse is uncommon in children. In adults, it can occur at any age, but is more common in the elderly. Women are six times more often affected than men. In women, prolapse of the rectum is commonly associated with prolapse of the uterus, or a past history of a gynaecological operation, e.g. hysterectomy. In the Middle East and Asia, complete rectal prolapse is not uncommon in young males. In approximately 50 per cent of adults, faecal incontinence is also a feature .bifferential diagnosis. In the case of a child with abdominal pain, prolapse of the rectum must be distinguished from ileocaecal intussusception protruding from the anus. Figures 60.13 and 60.14 make the differential diagnosis clear. In rectosigmoid intussusception in the adult, there is a deep groove (5 cm or more) between the emerging protruding mass and margin of the anus, into which the finger can be entered.

Treatment

Surgery is required and the operation can be performed via the perineal or the abdominal approaches. Whenever possible, an abdominal rectopexy is recommended, but when the patient is elderly and very frail, or is suffering from injury or disease of the spinal cord, or in very early life, a perineal operation is indicated.

Perineal approach. Two procedures have been used most commonly.

Delorme’s operation (Fig. 60.15). In this procedure, the rectal mucosa is removed circumferentially from the prolap­sed rectum over its length, apart from 0.5-cm strips at its proximal end and at its tip. The underlying muscle is then imbricated with a series of chromic catgut sutures, such that, when these are tied, the rectal muscle is concertinaed towards the anal canal. The anal canal mucosa is then sutured circumferentially to the rectal mucosa remaining at the tip of the prolapse. This manoeuvre has the effect of reducing the prolapse and creating a ring of muscle within the anal canal, which narrows the orifice and prevents recurrence.

Thiersch's operation. This procedure, which aims to place a steel wire or, more commonly now, a silastic or nylon suture, around the anal canal has in the past been the most frequently performed perineal procedure. However, it has become obsolete for the treatment of rectal prolapse in adults, although it still does have a place in the treatment of partial prolapse in children. The reasons for its lack of popularity are that the suture would often break or cause chronic perineal sepsis, or both, or the anal stenosis so created would produce severe functional problems. Delorme’s operation is now the preferred perineal operation.

If an abdominal repair must he avoided (e.g. in a young man in whom sexual potency must be preserved by avoiding damage to the pelvic nerves) more extensive perineal procedures are available. These include strengthening the puborectalis and external anal sphincters by an approach through the intersphincteric plane (see above), the so-called postanal repair (Parks) and perineal rectosigmoidectomy (Altemeier) in which the prolapsed rectum is exised from below.

Abdominal approach. The principle of all abdominal operations for rectal prolapse is to replace and hold the rectum in its proper position. Of the many operations described, the following are relatively simple. They are recommended in patients with complete prolapse, who are otherwise in good health.

Wells’ operation. In this operation the rectum is fixed firmly to the sacrum by inserting a sheet of polyvinyl alcohol sponge or, more commonly now, polypropylene mesh between them (Fig. 60.16). The rectum is separated from the sacrum in the Lisual way. The mesh is fixed by a series of sutures to the periosteum over the midline of the sacrum and is then wrapped loosely about the rectum covering all except the anterior wall. The free margins of the mesh are sutured to the lateral margins of the anterior wall of the rectum. The peritoneal floor is resutured so that the mesh is excluded from the peritoneal cavity. The mesh does not give rise to a foreign body reaction, but it does produce very marked fibrous tissue formation. Many proctologists regard this as the method of choice. Recently, the technique has been performed laparoscopically, thus reducing the operative trauma and limiting the time in hospital (Fig. 60.17).

Ripstein’s operation. In this operation, the rectosigmoid junction is hitched up by a Teflon sling to the front of the sacrum just below the sacral promontory. The operation is very safe and simple, and the results are good. Some surgeons recommend combining this procedure with resection of the sigmoid colon (Goldberg).

Lahaut’s operation. This operation depends entirely upon mobilising the rectum and lower sigmoid colon, and holding it up by taking it through the rectus sheath. The results are moderate and few surgeons use this method. It should he noted that approximately 50 per cent of adult patients with a complete rectal prolapse are incontinent, and rectopexy cures only about one-third. Consequently, it may be necessary to perform a subsequent procedure to correct the incontinence.