Sacral nerve stimulation for faecal incontinence secondary to congenital imperforate anus

After treatment in infancy, patients with imperforate anus can develop bowel dysfunction in adult life. Low anorectal malformations are often associated with congenital deformity of the sacrum and coccyx (sacrococcygeal agenesis). Sacral nerve stimulation (SNS) is an effective treatment for incontinent patients with an accompanying acquired sphincter defect. We report two patients treated by SNS for faecal incontinence secondary to congenital imperforate anus. Two adults presented with faecal incontinence. Both had a congenital imperforate anus. The first, a female 36 years old, suffered from lifelong incontinence. She had daily passive soiling, a sensation of incomplete emptying and urgency (less than 5 min). The second, a male 35 years old, had had incontinence since adulthood. He had urgency (2 min) and daily soiling. Both had undergone coloanal pull-through procedures in infancy. Anal manometry showed a low resting pressure in both patients (30 and 33 cm H₂O) and a reduced peak squeeze pressure increment (15 and 40 cm H₂O). Endoanal ultrasonography demonstrated a complete ring of muscle around the neo-anus in both patients. The patients underwent peripheral nerve evaluation (PNE). Both had partial sacral agenesis, which made this technically difficult. After 3 weeks of PNE, the female patient showed no improvement, but the male patient had no further episodes of incontinence and urgency improved from 2 to 15 min. Accordingly, he underwent implantation of a permanent pulse generator. SNS may be effective for some incontinent patients with imperforate anus even in the presence of partial sacral agenesis. The clinician should be aware of any associated sacral agenesis and the technical difficulty this may cause. Alternative methods of neuromodulation, such as pudendal nerve stimulation, could be considered in such cases.