EP1003 - Eliminating the Routine Protective Ileostomy: A Pilot Study of Modified Four-Quadrant Enhanced Coloanal Anastomosis (fqeCAA-ISR) for Ultra-Low Rectal Cancer

Purpose/Background: Intersphincteric resection (ISR) is a sphincter-preserving procedure for ultra-low rectal cancer (uLRC), yet conventional hand-sewn coloanal anastomosis carries a substantial risk of anastomotic leakage (AL), often necessitating a protective stoma. The primary mechanism underlying AL includes anastomotic high tension and colonic retraction, particularly at the posterior wall due to factors such as traction from the hiatal ligament and sphincter spasm. To address these challenges, we developed a novel four-quadrant enhanced coloanal anastomosis (fqeCAA) technique. This approach innovatively combines mechanical fixation (seromuscular layer to the levator ani muscle) with anatomic sealing (full-thickness coloanal suture) to mitigate retraction forces and reduce tension at the anastomotic site. The aim of this study was to evaluate the safety and feasibility of fqeCAA in reducing AL incidence and potentially obviating the need for a protective stoma.

Methods/Interventions: This prospective single-center pilot study enrolled consecutive patients with uLRC who underwent laparoscopic ISR with fqeCAA between February 2024 and August 2025. The fqeCAA technique consisted of three critical steps:

1) Anchoring suture: A four-quadrant discontinuous suture was placed between the seromuscular layer of the colon and the levator ani muscle aperture to stabilize the bowel, minimize colonic contractions, and reduce anastomotic tension;

2) Reinforced anastomosis: An interrupted full-thickness suture was performed to complete a hand-sewn end-to-end coloanal anastomosis, enhancing structural integrity;

3) A protective stoma was not routinely created.

Primary endpoints included AL rate (Clavien-Dindo ≥ Grade III) and annal function.

Results/Outcomes: Among 35 patients who underwent fqeCAA-ISR, 25 (71.4%) were female, and 26 (74.3%) received neoadjuvant (chemo)radiotherapy. The median tumor distance from the anal verge was 21 mm. All procedures achieved R0 resection and finished fqeCAA-ISR without protective stoma. The median operative time was 150 minutes, with a median blood loss of 20 mL. No intraoperative complications occurred. The median distance from anastomotic site to anal margin was 10 mm. Over a median follow-up of 18 months, the overall AL rate was 2.9% (1/35), with only one case with grade III Clavien-Dindo Classification requiring surgical reintervention. Other complications included anastomotic stenosis (5.7%), mild retraction (2.9%), high fever (2.9%), rectal prolapse (5.7%), and pelvic infection (8.6%). Functional outcomes were favorable, with a median LARS score of 34 (severe grade 67.6%) and a Wexner score of 14 (severe grade 47.1%).

Conclusion/Discussion: The fqeCAA-ISR technique demonstrates notable innovation through its dual-layer anchoring strategy, which effectively addresses the key mechanism of AL-postoperative colonic retraction. This pilot study confirms its safety and feasibility, showing a markedly low AL rate (2.9%) and a high stoma-free success rate, suggesting potential as a stoma-sparing option for select patients with uLRC. Long-term functional and oncological outcomes warrant further validation in larger cohorts.