Chapter 14 — Rectal Prolapse

Rectal prolapse means the rectum slides down and out through the anus. It is distressing for the patient. It is also very treatable. This chapter explains rectal prolapse in full. It covers presentation, examination, differential diagnosis, investigations, and management. This is the same pattern used for every disease chapter in this manual.

14.1 What Is Rectal Prolapse

The rectum normally stays fixed in place. It is held by ligaments. It is supported by the surrounding pelvic floor muscles. It is also anchored by its own attachment to the sacrum. When this support weakens, the rectum can slide downward.

In a mild case, only the inner lining slides down. In a full case, the whole thickness of the rectal wall comes out through the anus. This chapter covers both patterns.

Rectal prolapse is most common in older women. It is linked to a weak pelvic floor, long- standing straining, and sometimes to childbirth injury. It can also occur in young children, and in men, though less often.

14.2 Why It Happens

Several factors weaken the normal supports of the rectum over time. Chronic straining is one of the most common. It often comes from long-standing constipation. Repeated straining stretches the ligaments and the pelvic floor muscles.

Childbirth can injure the pelvic floor and the anal sphincter directly. This injury adds to the risk of prolapse later in life. A chronic cough can add further strain to the same supporting structures. So can heavy lifting over many years.

In children, prolapse is usually linked to a different cause. It often follows straining from constipation, a chronic cough, or an underlying condition such as cystic fibrosis. Most childhood cases resolve once the underlying cause is treated.

14.3 Classification

Rectal prolapse is classified by how much of the rectal wall comes down, and how far it protrudes.

Mucosal prolapse — only the inner lining slides down. It usually protrudes only a short distance. It is sometimes mistaken for large haemorrhoids. Full-thickness prolapse — the whole wall of the rectum comes down. This is the classic, complete rectal prolapse. It can protrude several centimetres. Internal prolapse, or intussusception — the rectal wall folds inward on itself. It does not come out through the anus. It does not show on external examination. Chapter 15 covers this separately.

The distance the prolapse protrudes matters for planning treatment. Whether it reduces on its own also matters. This chapter records both features at every assessment.

14.4 Presentation

Follow the history-taking method described in Chapter 2. Certain features are typical of rectal prolapse.

A visible lump or mass that comes out of the anus, often during straining or defecation. The lump may reduce on its own, or may need to be pushed back manually. Mucus discharge, and sometimes bleeding, from the exposed rectal lining. A feeling of incomplete emptying after defecation. Faecal incontinence, in a long-standing or large prolapse. The anal sphincter stretches over time. This is why incontinence develops. Constipation and straining. These often exist before the prolapse begins. They can also follow, once the prolapse has weakened the pelvic floor further.

Ask how far the prolapse protrudes. Ask whether it now stays out permanently. Ask about any related bowel symptoms, such as straining or a sense of incomplete emptying. This history guides the choice of investigation.

14.5 Examination

Follow the sequence from Chapter 3. Some steps need particular attention for rectal prolapse.

See Chapter 4 for the inspection method. Inspection is often normal at rest. The prolapse may only appear on straining. Ask the patient to strain, or to sit on a commode and bear down. This allows the prolapse to be seen directly.

A full-thickness prolapse shows circular folds of rectal mucosa. A mucosal prolapse shows radial folds instead. This distinction helps confirm the type of prolapse.

Digital rectal examination checks the resting tone and the squeeze pressure of the sphincter. A weak sphincter often coexists with a long-standing prolapse. This affects the choice of operation.

Examine for a rectocele or other pelvic floor problem at the same visit. These often occur together. Both may need attention.

14.6 Differential Diagnosis

A few conditions can look similar to rectal prolapse on first inspection.

Large prolapsing haemorrhoids — show radial grooves rather than circular folds. Chapter 10 covers this distinction in more detail. Rectal polyp or tumour — can protrude through the anus in a large or pedunculated case. Any unusual or irregular tissue should be biopsied. Anal skin tags or perianal masses — sit at the anal margin rather than protruding from within the rectum.

A careful look at the pattern of the folds usually settles the diagnosis on examination alone. This pattern is described above.

14.7 Investigations

A visible, reducible prolapse on examination often needs no further imaging to confirm the diagnosis.

Defecography shows the rectum during active straining. Its MRI equivalent does the same. Either is useful when the prolapse is not obvious in the clinic. Either is also useful when an internal prolapse is suspected.

Colonoscopy is advisable before surgery in an older patient. This rules out a polyp or tumour as a contributing cause.

Anorectal manometry is described in Chapter 8. It helps assess sphincter function before planning an operation. This is especially useful when incontinence is already present.

14.8 Principles of Management

Surgery is the definitive treatment for a full-thickness rectal prolapse. No non-surgical treatment corrects the underlying weakness.

A mild, mucosal prolapse can sometimes be managed conservatively at first. This includes treating constipation and reducing straining. Surgery is considered if symptoms persist.

The choice of operation balances two things: the durability of the repair, and the fitness of the patient for surgery. This balance shapes every decision in this chapter.

14.9 Surgical Techniques

Operations for rectal prolapse fall into two broad groups. Perineal approaches are done from below. Abdominal approaches are done from within the abdomen.

14.9.1 Perineal Approaches

Delorme's procedure — the prolapsed mucosa is stripped away. The underlying muscle layer is folded and stitched to shorten it. This suits a shorter, mucosal or partial prolapse. Altemeier's procedure, or perineal rectosigmoidectomy — the prolapsed bowel is removed from below. The remaining ends are joined together. This suits a longer, full-thickness prolapse in a frail patient. Thiersch procedure, or anal encirclement — a band or suture is placed around the anus to narrow it. This does not correct the prolapse itself. It is a supportive measure. It is most often used in a very frail patient unfit for a larger operation. Section 14.11 covers this procedure in more detail.

A perineal approach avoids an abdominal incision. It suits an older or frail patient. It carries a higher rate of recurrence than an abdominal approach.

14.9.2 Abdominal Approaches

Suture rectopexy — the rectum is mobilised and fixed to the sacrum with sutures. No bowel is removed. Resection rectopexy — the rectum is mobilised and fixed to the sacrum. The redundant sigmoid colon is also removed. This suits a patient with significant constipation alongside the prolapse. Ventral mesh rectopexy — a strip of mesh supports the front of the rectum. The mesh is fixed to the sacrum, without a posterior dissection. This has a lower risk of new constipation than a posterior rectopexy.

An abdominal approach can be done openly or laparoscopically. It gives a more durable repair, with a lower recurrence rate. It suits a fitter patient who can tolerate a longer operation.

A note of caution on mesh: synthetic mesh in ventral rectopexy has come under increasing scrutiny in recent years. Similar concerns have been raised about pelvic mesh in gynaecological surgery. Mesh erosion into the rectum or vagina, chronic pain, and infection have all been reported. Many surgeons now prefer biological mesh, or avoid mesh altogether in favour of suture rectopexy, particularly in a younger patient. This remains an evolving area, not settled practice, and should be discussed openly with the patient as part of consent.

14.10 Choosing an Approach

Age and fitness guide the choice more than the prolapse itself. A fit patient usually benefits most from an abdominal repair. This is because of its durability, regardless of the patient's age.

A frail or elderly patient with significant medical illness is often better served by a perineal approach. The lower physiological demand of the operation outweighs its higher recurrence rate in this group.

Discuss the trade-off clearly with the patient. A perineal operation is easier to recover from. It is also more likely to need repeating later. An abdominal operation asks more of the patient at the time of surgery. It is less likely to fail later.

14.11 The Thiersch Procedure — A Historical Note

The Thiersch procedure has a long history in the surgical treatment of rectal prolapse. A dedicated case history is discussed in the author's companion volume, A Surgeon's History of Anorectal Disease. That volume traces the evolution of this technique, from its original description to its current, limited role.

In current practice, the Thiersch procedure is rarely used as a stand-alone cure. It remains useful as a temporary or palliative measure, in a patient too frail for a definitive repair. This chapter records it for completeness. It also places it correctly alongside the more durable modern operations described above.

14.12 Special Situations

Paediatric rectal prolapse — is usually mucosal. It often resolves with treatment of the underlying cause, such as constipation or a chronic cough. Surgery is rarely needed in a child. Recurrent prolapse — needs careful reassessment of the original operation and the patient's current fitness. A different technique is often chosen for the repeat procedure. Prolapse with faecal incontinence — often improves after successful repair. Much of the incontinence was caused by the prolapse itself, stretching the sphincter over time. Prolapse with obstructed defecation — needs careful assessment. Correcting the prolapse alone may not resolve the obstructed defecation. Chapter 16 covers this overlap in more detail. Prolapse in pregnancy — is uncommon, but can occur due to the pressure of the growing uterus. Conservative management is preferred until after delivery, unless the prolapse is severe.

14.13 Complications of Treatment

Every prolapse operation carries some risk. This should be explained clearly to the patient before surgery.

Recurrence, more common after a perineal approach than an abdominal one. New or worsened constipation, particularly after a posterior rectopexy. Bleeding or infection at the operative site. Anastomotic leak, in an operation that involves joining two ends of bowel together. Persistent incontinence, if the sphincter damage predates the operation and does not fully recover. Mesh-related complications, such as erosion or infection, in a ventral mesh rectopexy.

14.14 Common Mistakes to Avoid

Diagnosing haemorrhoids in a patient with an undetected rectal prolapse. Choosing a major abdominal operation for a very frail patient who cannot tolerate it. Missing an underlying tumour as the cause of a prolapse in an older patient. Failing to assess sphincter function before planning surgery. Treating the prolapse alone in a patient with coexisting obstructed defecation, and overlooking the second problem.

14.15 Recording and Follow-Up

Record the type of prolapse, its length, and whether it reduces on its own. Record the sphincter tone on examination. For example: "Full-thickness rectal prolapse, 6 cm, reduces spontaneously. Sphincter tone reduced." Arrange follow-up to confirm healing. Check bowel function and continence after surgery.

14.16 Why This Chapter Matters

Rectal prolapse causes real distress. It responds well to the right operation, chosen for the right patient. The next chapter turns to rectal intussusception. This is the internal counterpart of the condition described here. It hides within the rectum, rather than protruding through the anus.