Presacral sinus after minimally invasive rectal resection: delayed complications following stoma closure in a case series

Presacral sinus (PS) is a late sequela of anastomotic leakage that fails to heal following restorative rectal resection. Clinical outcomes following expectant management and subsequent stoma closure remain poorly defined. This single-center case series included patients who developed PS after minimally invasive restorative low anterior resection with defunctioning ileostomy for rectal cancer between 2013 and 2023. PS was defined as a leak-associated presacral cavity persisting beyond 90 days from the index operation; eligibility was anchored on a documented leak with such a cavity, irrespective of when the sinus was first recognized. Patients with concurrent severe anastomotic stricture or rectovaginal fistula requiring surgical intervention were excluded. All patients were initially managed expectantly, with or without adjunctive transanal repair, followed by stoma closure. Long-term clinical and radiological outcomes were evaluated. Of 1,010 patients undergoing minimally invasive restorative rectal resection, 24 (2.4%) were identified as having a PS; after exclusions, 17 met the inclusion criteria and all underwent stoma closure. After a median follow-up of 53 months, eight patients (47%) developed major complications, including pelvic abscess, necrotizing fasciitis, enterocutaneous fistula, bilateral ureteric obstruction, and pseudo-obstruction. Six required permanent fecal diversion. The median interval from stoma closure to reoperation was 13 months (range 2–32 months). Among patients without complications, four achieved complete resolution, while five had persistent but asymptomatic sinuses. Complications were numerically more frequent with complex sinus morphology (7/11 vs 1/6) and a preceding Grade B leak (4/5 vs 4/12), though neither difference was significant ( p = 0.131 for both). Excluding the two patients whose sinus was recognized only after closure, complications occurred in 7 of 15 (46.7%). Despite apparent improvement or resolution of PS on pre-closure imaging, complications remained common after stoma closure. PS may remain clinically silent after restoration of bowel continuity, but carries a substantial risk of delayed complications. Additional treatment strategies beyond expectant management should be considered before stoma closure, particularly with complex sinus morphology or a preceding Grade B leak.