Successful overlapping anal sphincter repair: relationship to patient age, neuropathy, and colostomy formation

Fecal incontinence from single anal sphincter defects are surgically remedial and commonly the result of obstetric injuries. Overlapping anal sphincter repair has previously been associated in small series with good results in 69 to 97 percent of patients.

The aims of this study were to assess the results of overlapping anal sphincter repair in one institution and to assess the effects of age, presence of a neuropathy, and addition of a temporary colostomy on the success of surgery.

A study of 57 overlapping anal sphincter repairs in 56 (54 females) patients at the Royal Prince Alfred Hospital during a six-year period was performed. All patients were investigated preoperatively with endoanal ultrasound and concentric needle electromyography. Patients have been assessed prospectively since 1994 with a questionnaire, including a four-point Likert scale of continence level, the St. Mark's incontinence scoring system (range, 0-13), the Pescatori incontinence scoring system (range, 0-6), and patient assessment of success or failure of the overlapping anal sphincter repair. A colostomy was selectively formed in conjunction with an overlapping anal sphincter repair in 21 patients (8 preoperatively, 13 simultaneously), and 18 patients had a concomitant neuropathy (3 unilateral, 15 bilateral).

After a median follow-up of 18 months, median continence scores overall had improved from St. Mark's incontinence scoring 13 to 3 (P < 0.0001) and Pescatori incontinence scoring 6 to 2 (P < 0.0001). Forty-nine of 57 (86 percent) repairs have been successful, and 8 are considered to be failures. Twenty-one of 27 (78 percent) repairs in patients younger than 40 years of age were successful, as were 28 of 30 (93 percent) repairs in patients older than 40 years of age (P = 0.10). Four of 18 (22 percent) repairs associated with a neuropathy failed compared with 4 of 39 (10 percent) without a neuropathy (P = 0.21). Improved or normal continence was achieved in 17 of 21 (81 percent) patients with a stoma and overlapping anal sphincter repair and in 32 of 36 (89 percent) patients with an overlapping anal sphincter repair alone (P = 0.32). The presence of a stoma did not improve the rate of wound healing by primary intention (62 percent for stoma vs. 64 percent for overlapping anal sphincter repair alone; P = 0.55).

Single anal sphincter defects can be successfully treated with an overlapping anal sphincter repair. There is no improvement in primary healing with selective stoma formation. Age of the patient and presence of a neuropathy should not detract from proceeding with overlapping anal sphincter repair when singular anal sphincter defects are detected on endoanal ultrasound in muscle that is still active.