Faecal Incontinence Requiring Surgery

Faecal incontinence is recurrent uncontrolled passage of stool caused by dysfunction of the anal sphincters, rectal reservoir, pelvic floor, stool consistency or neural pathways.

Surgery is considered only after defining the mechanism and optimising reversible contributors.

Common surgical causes include obstetric external sphincter injury, previous anorectal operations, rectal prolapse and pelvic surgery.

Determine whether leakage involves gas, liquid stool or formed stool and whether it occurs with urgency or without awareness.

Assess frequency, pad use and impact on daily function.

Look specifically for:

• Obstetric trauma
• Previous sphincterotomy or fistula surgery
• Rectal prolapse
• Chronic diarrhoea
• Neurological disease
• Severe constipation with overflow

Digital rectal examination assesses resting tone, squeeze and obvious sphincter defects.

Endoanal ultrasound: defines structural external and internal sphincter defects when reconstruction is being considered.

Anorectal manometry can characterise pressures and sensation but does not reliably determine which patient will respond to sacral neuromodulation.

Optimise stool consistency before surgery.

For loose stool:

Loperamide 2 mg orally after loose stool or before predictable periods of symptoms, titrated carefully to avoid constipation. Regular regimens of 2 to 4 mg before meals can be used when required.

Pelvic floor rehabilitation and biofeedback should be attempted in suitable patients.

Sacral neuromodulation

Sacral neuromodulation is a major first line surgical option with or without a visible sphincter defect.

Perform temporary test stimulation first.

Proceed to permanent implantation when faecal incontinence episodes improve by at least approximately 50% during the test period.

Sphincteroplasty

Overlapping external anal sphincteroplasty can be considered when there is a discrete anatomical external sphincter defect, particularly a relatively recent obstetric injury.

Short term results can be good, but continence frequently deteriorates over subsequent years. Long standing obstetric incontinence presenting decades after delivery may therefore be better suited to neuromodulation than routine sphincter reconstruction.

Do not routinely repeat failed sphincteroplasty because subsequent durability is poor.

Diversion

A colostomy is an effective definitive option for severe refractory incontinence when neuromodulation and other treatments have failed or are unsuitable. For selected patients, predictable stoma function produces a major improvement in quality of life.