RECOVERY OF THE INTERNAL ANAL-SPHINCTER AND CONTINENCE AFTER RESTORATIVE PROCTOCOLECTOMY

The internal anal sphincter (IAS) was assessed prospectively using ele ctromyography and manometry in 66 patients (48 men) undergoing restora tive proctocolectomy to determine its role in the gradual return of co ntinence. Twenty-nine patients received a J pouch and 37 a W reservoir . Some 38 pouches (J, ten; W, 28) were hand-sewn (mucosal proctectomy with endoanal anastomosis) and 28 (J, 19; W, nine) stapled (end-to-end pouch-anal anastomosis 1 cm above the dentate line). Twelve patients underwent a one-stage procedure (all J pouches), while the remainder h ad a covering loop ileostomy. Each patient was reassessed immediately after restorative proctocolectomy and again at 7 days, 1 month, 4 mont hs, 9 months and 18 months after pouch formation. Internal sphincter e lectromyographic activity was greatly reduced after pouch-anal anastom osis (median preoperative frequency 0.51 Hz versus immediate postopera tive frequency 0.21 Hz, P<0.003) and gradually recovered from 4 months after surgery. At 18 months, measurements of IAS function had not ful ly recovered to preoperative values (median frequency 0.31 Hz; P<0.03) . Resting anal pressures (median preoperative value 99 cmH(2)O) decrea sed by over 50 per cent after surgery (median immediate postoperative resting pressure 44 cmH(2)O) and recovered gradually but incompletely (median pressure at 18 months 63 cmH(2)O). Eleven patients reported le akage in the follow-up period. The median (range) resting pressure in these patients (54 (40-71) cmH(2)O) was not significantly different at 9 months from that of those who were continent either before or after operation (59 (46-68) cmH(2)O). Prolonged recordings in patients with faecal leakage revealed evidence of high-pressure pouch waves that ov erwhelmed anal sphincter pressures and coincided with leakage. These e pisodes were most common during sleep, when anal sphincter activity wa s reduced.