Variation in rectoanal inhibitory reflex after laparoscopic intersphincteric resection for ultralow rectal cancer

Aim The aim was to evaluate the physiological variation in rectoanal inhibitory reflex (RAIR) after laparoscopic intersphincteric resection (Lap-ISR) for ultralow rectal cancer. Method This was a retrospective study that included 56 patients who underwent Lap-ISR from a prospectively collected database. The RAIR was examined preoperatively and up to 12 months after ileostomy closure. The primary outcome included physiological variation in RAIR and its difference between partial, subtotal and total ISR. The secondary outcome was its correlation with functional outcome. Results The reflex was present in 95% (53/56) of patients preoperatively, in 36% (20/56) before ileostomy closure, in 48% (27/56) at 3-6 months and in 61% (34/56) at 12 months after ileostomy closure. The elicited volume of RAIR was significantly increased at 12 months after ileostomy closure than at baseline (P = 0.005), but its duration and amplitude did not differ significantly. There was no significant difference in the reflex recovery between the ISR groups (partial vs. subtotal vs. total: 65% vs. 63% vs. 44%, P = 0.61). At 12 months after ileostomy closure, the RAIR-present group had favourable functional results and patient satisfaction (P < 0.05). Major faecal incontinence was found in 82% of patients in the RAIR-absent group. Conclusion The RAIR is abolished in the majority of patients after Lap-ISR, but a time-dependent recovery could be observed in more than half of the patients. The reflex recovery is not influenced by the resection grade of the internal sphincter. However, persistent loss of the RAIR correlates with worse continence.