The effect of endoscopic mucosal resection and transanal endoscopic microsurgery on anorectal function

The study assessed the impact on anorectal function of endoscopic mucosal resection (EMR) and transanal endoscopic microsurgery (TEM) of large rectal adenomas.

Patients with a large (≥ 3 cm) rectal adenoma undergoing EMR or TEM were included. Self-reported faecal incontinence was assessed using the Colorectal Functional Outcome (COREFO) questionnaire and the Wexner Incontinence Grading Scale. Anorectal manometry was performed before and at 6 months after treatment to measure anal resting (ARP) and squeeze pressure (SP), squeeze endurance (SE), the rectoanal inhibitory reflex (RAIR), rectal volumetry of first sensation (FS), first urge (FU), maximum tolerable volume (MTV) and rectal compliance (RC).

Twenty-four patients were included in the study, of whom 11 underwent EMR and 13 underwent TEM. The mean adenoma size was 51 ± 19 mm and the median distance from the anal verge was 3 cm (interquartile range 1-10 cm). Follow-up data were available from 20 patients; one patient had died and three had undergone total mesorectal excision. Incontinence for liquid stool and Wexner score decreased significantly after treatment. In contrast, none of the measured parameters of anorectal motility (ARP, SP, SE, RAIR, RC) and perception (FS, FU, MTV) was affected by adenoma resection. No differences were found in baseline and follow-up incontinence and functional parameters between intervention groups, except for postprocedural ARP, which was lower after TEM than after EMR.

Continence in patients with a large rectal adenoma improved after EMR or TEM, probably due to decreased rectal mucus production. Anal sphincter pressure, rectoanal reflexes, rectal sensation and compliance were not affected by adenoma resection.