OBJECTIVEThe short-term efficacy of the transanal one-stage endorectal pull through operation for Hirschsprung's disease is satisfactory. However the long-term outcome of anorectal function has not been fully understood. The aim of this study was to evaluate the stooling pattern, colonic motility and anal sphincter performance after transanal one-stage pull through operation in children with Hirschsprung's disease.

METHODSFifty-eight children who underwent transanal one-stage pull through operation for Hirschsprung's disease were followed up. The mean follow-up duration was 15.8 months (range, 6-24 months). The stooling patterns of the patients were investigated by the informed questionnaire. Barium enema, defecography, total and segmental colonic transit time and the anorectal vector manometry were performed. Thirty- three healthy children were used as controls.

RESULTSMost of patients had normal stool consistency and frequency. Postoperative enterocolitis occurred in 3 patients, and constipation was found in five patients. Postoperative soiling was observed in 9 patients. None of the 58 patients had incontinence, cuff infection, anastomotic leak and mortality. The barium enema showed that the configuration of the colon recovered well in most of patients. Postopertive defecography showed the anorectal angle of all the patients was open, fixed and bigger than that of preoperation and the healthy controls (P < 0.01). Postoperatively, the mean total gastrointestinal transit time (TGITT), the left colonic transit time (LCTT) and rectosigmoid colonic transit time (RSTT) in the 58 patients were significantly shorter than preoperatively (P < 0.01) and were similar to those of the control group. The rectoanal inhibitory reflex was regained in 5 patients. The anal maximal pressure of the patients with constipation in resting and squeezing condition were significantly higher than those of the asymptomatic patients and controls (P < 0.05). The vector volume (VV) and vector symmetric index (VSI) in patients with soiling were significantly lower than those in preoperation and the controls (P < 0.05). The VSI in the patients with constipation was significantly higher compared with the controls (P < 0.05).

CONCLUSIONSThe stooling function, colonic motility and anal sphincter performance manifest well in most of the patients after the transanal endorectal pull through operation for Hirschsprung's disease. Stooling disorders in few cases are probably related to decrease or disappearance of the sigmoid loops, dysfunction of the "neorectosigmoid", an open and fixed anorectal angle and achalasia of the internal anal sphincter.