Objective: Many patients experience disordered defaecation after low anterior resection of the rectum (LARR). We analysed the anorectal function of these patients to determine which factors might contribute to this problem.
Patients and methods: Between November 2002 and January 2004, 18 consecutive patients (11 males and 7 females) who underwent LARR with total mesorectal excision (TME) for rectal cancer were assessed by anorectal manometry, balloon proctometry and the Wexner continence questionnaire before operation and at 6 months and 1 year following stoma closure. Sixteen volunteers (11 males and 5 females) were evaluated for comparison. Stepwise logistic regression was performed for variables that were highly significant at univariate analysis.
Results: The mean daily preoperative stool frequency was 2, mean basal pressure (MBP) 43.12 cm H(2)O, maximum threshold volume (MTV) 181.8 ml, length of high-pressure zone (HPZ) 3.11 cm and the rectoanal inhibitory reflex (RAIR) was present in all the patients. Twelve months after stoma closure, the stool frequency was 3.3, MBP 37.7 cm H(2)O, MTV 146.3 ml, length of HPZ 2.88 cm and Wexner score 4.37. Comparing patients having a good anorectal function (Wexner score > or = 5) with those having an unsatisfactory function, we found that, on multivariate analysis, the factors that independently contributed to a poor outcome at 12 months after operation were the absence of RAIR as well as an MTV and HPZ below the fifth percentile of normal individuals.
Conclusions: Many patients undergoing LARR with TME for rectal cancer experience an anterior resection syndrome that persists for at least 1 year. Those with no RAIR and subnormal MTV and HPZ lengths can be predicted to have an unsatisfactory outcome.