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Stoma-Free Intersphincteric Resection in Low Rectal Cancer under standardized perioperative protocols

Low rectal cancer (<5cm from anal verge) poses surgical challenges. For ultra-low cases needing sphincter preservation, Intersphincteric Resection (ISR) with Total Mesorectal Excision (TME) is the standard. While ISR ensures oncological radicality, anastomotic leak risk necessitates a routine diverting stoma. This practice, however, carries stoma-related complications, reduces quality of life, and requires a second reversal surgery. Therefore, achieving stoma-free ISR without increasing the risk of anastomotic leakage would prevent stoma-related complications, avoid a definitive second surgery, and reduce healthcare costs. Division of Gastrointestinal Surgery from West China Hospital of Sichuan University has long been dedicated to exploring stoma-free strategies for ISR, developing a comprehensive and standardized perioperative protocol with excellent clinical outcomes.

For patients with low rectal tumors not receiving neoadjuvant radiotherapy, our stoma-free ISR procedure demonstrates remarkably low 30-day rates of Grade C anastomotic leak (1.3%) and Clavien-Dindo ≥ Grade III complications (2.5%). Our overall anastomotic leak rate is a low 2.5%. These favorable results stem from significant technical refinements targeting the two primary failure mechanisms identified in previous studies: anastomotic tension and marginal ischemia.

In addition, this approach successfully overcomes previous challenges, facilitating timely restoration of bowel continuity while maintaining procedural simplicity—a crucial advantage both clinically and economically. The stoma-free method demonstrates a 34% reduction in median hospitalization costs (RMB 29,598 vs. 49,734; p=0.004) and a 20% shorter postoperative hospital stay (5 days vs. 6 days; p<0.001), primarily due to avoiding stoma-related expenses and complications. Our key improvements include: 1) A double-layer interrupted anastomosis technique: involving deep fixation to the sphincter muscle layer followed by mucosal apposition. 2) Preservation of the left colic artery (LCA): To optimize blood supply. 3) Intraoperative indocyanine green (ICG) perfusion assessment: To verify adequate blood flow at the anastomotic margin. 4) A standardized enhanced recovery after surgery (ERAS) perioperative protocol and a structured system for complication monitoring. 5) A transanal drainage protocol to prevent major (Grade C) leak events.

West China Hospital's standardized stoma-free ISR offers a safe, effective, and cost-efficient sphincter-preserving option for selected patients with low rectal cancer, enhancing recovery and quality of life.

Surgical Technique Overview

Abdominal Phase (Laparoscopic): The patient is positioned in modified lithotomy. TME is performed with routine LCA preservation. Dissection extends to the pelvic floor and into the intersphincteric space, preserving pelvic autonomic nerves. The mesentery is divided 10-15 cm proximal to the tumor.

Transanal Phase: After anal dilation and eversion, a purse-string suture is placed 0.5 cm distal to the tumor. A full-thickness circumferential incision is made 0.5 cm below this, connecting with the abdominal dissection. The specimen is exteriorized transanally and divided 10-15 cm proximal to the tumor. Negative distal margins are confirmed intraoperatively by frozen section.

Anastomosis: After confirming negative margins and adequate perfusion via ICG, a double-layer hand-sewn colo-anal anastomosis is performed:

1) First Layer: 8-10 interrupted 2-0 absorbable sutures approximate the proximal colon's muscularis (0.5-0.8 cm from the edge) to the deep sphincter muscle.

2) Second Layer: 8-10 interrupted 3-0 absorbable sutures achieve mucosal/submucosal apposition.

3)

Finalization: A transanal drainage tube wrapped in Vaseline gauze is placed. Pneumoperitoneum is re-established to check for torsion, tension, or bleeding, and a pelvic drain is placed.