[Preliminary outcomes of modified Bacon procedure combined with priority intersphincteric- plane dissection via the jack-knife transanal approach for special-type ultra-low rectal cancer].

Objective: To explore the feasibility and short-term outcomes of the jackknife position transanal-priority intersphincteric space (ISS) dissection combined with the modified Bacon procedure for special types of ultra-low rectal cancer. Methods: A retrospective observational study was performed. Clinical data of 7 patients with ultra-low rectal cancer who underwent transanal-first ISS dissection combined with modified Bacon technique for staged reconstruction at Zhongnan Hospital of Wuhan University between September 2024 and August 2025 were retrospectively analyzed. The patients were aged (58.3±11.2) years with a body mass index of (23.0±2.9) kg/m². Based on preoperative pelvic MRI measurement, the median distance from the inferior tumor margin to the anal verge was 3.0 (2.4, 3.4) cm. Four patients received neoadjuvant chemoradiotherapy and achieved tumor regression. Among the 7 patients, preoperative imaging and digital rectal examination indicated anterior wall tumor involvement (partial or circumferential) in 6 cases, and tumor located at the right posterior wall in 1 case; one patient was complicated with drug-induced osteonecrosis of the femoral head and could not tolerate the conventional lithotomy position. Perioperative parameters and short-term oncological outcomes were analyzed. Results: All seven patients underwent successful laparoscopic surgery without conversion to open surgery or prophylactic stoma creation. The median operative time was 210 (180, 220) minutes, with intraoperative blood loss of 50 (50, 100) ml. Two perioperative complications occurred, both resolved conservatively. All cases achieved negative circumferential margins with a distal margin distance of 1.0 (0.5, 1.3) cm. Median follow-up was 18 (13, 19) months, with one case showing distant metastasis and no recurrence in the remaining patients. Overall, patients reported satisfactory anal function. Conclusion: The combination of the jackknife position transanal-priority ISS dissection and the modified Bacon procedure is a feasible and safe sphincter-preserving strategy for patients with ultra-low rectal cancer characterized by unfavorable tumor location, challenging anatomy, or high anastomotic risk. It serves as an effective supplementary option for managing such complex cases.