Mesorectal excision for rectal cancer: functional outcome after low anterior resection and colorectal anastomosis without a reservoir

Abstract

OBJECTIVE: The anal sphincters, neorectal capacity and motility may be affected by injury to the autonomic nerves during rectal resection. Anorectal function also depends on the method used for restoration of intestinal continuity, and colonic reservoir reconstruction has been recommended in ultralow anastomosis. This study was undertaken to evaluate the results after nerve preserving mesorectal excision and colorectal anastomosis without a reservoir. PATIENTS AND METHODS: Thirty-five consecutive patients who underwent low anterior resection with primary healing of the anastomosis, were included. Anal manometry with stationary pull through technique, rectal volumetry and symptom scoring (written questionnaires with visual analogue scales) were performed prior to and 12 months after surgery. Anal sphincter function was evaluated in all patients, but five patients with a colonic reservoir were excluded from the other evaluations. Thirty patients entered the main study; 14 patients having a total mesorectal excision (TME) and a low anastomosis (LA) (4-6 cm) and 16 patients a partial mesorectal excision (PME) and a high anastomosis (HA) (7-11 cm from the anal verge). RESULTS: Anal resting and squeeze pressure and rectal sensibility (threshold volume) were unchanged after the operation. The rectal volume eliciting urge to defecate was reduced from median 95 ml to 70 ml (P < 0.01), and the maximum tolerable rectal volume was reduced from 200 to 135 ml (P < 0.01) after the operation. The maximum tolerable volume was significantly lower in patients with LA than in patients with HA (P < 0.01). Overall functional results were good. The patients reported problems with complete bowel emptying (median VAS-score reduction from 90 to 60, P < 0.01), and minor incontinence problems (median VAS-score reduction from 100 to 90, P= 0.03). The reduction of VAS-scores was more pronounced in LA than HA patients (without reaching statistical significance). CONCLUSIONS: Anal sphincter function was preserved after mesorectal excision. Neorectal capacity was reduced, most pronounced in patients with LA. The overall functional results were satisfactory and slightly better in patients with HA than in those with LA.