Advanced Reconstructive Techniques: Mitigating Low Anterior Resection Syndrome Post-TME in Low Rectal Cancer - A Single-Center Randomised Controlled Study.

Background: Low Anterior Resection Syndrome (LARS) is a debilitating complication of sphincter-preserving surgeries, particularly after Total Mesorectal Excision (TME) for very low rectal cancer. LARS adversely impacts bowel function and quality of life, highlighting the need for effective preventive strategies. Objective: This study evaluates advanced reconstructive techniques, including taeniectomy pouch (TP), transverse coloplasty (TCP), colonic J-pouch (CJP), smooth muscle plasty (SMP), and greater omentum transplantation (GOT), in reducing LARS incidence and severity. Methods: This was a single-center randomized controlled trial (RCT) conducted between April 2018 and March 2024, involving 88 patients undergoing total mesorectal excision (TME) for very low rectal cancer. The trial was registered locally at our tertiary referral center. Patients were randomized in a 1:1 ratio to either the control group (straight coloanal anastomosis) or the test group (advanced reconstructive techniques: transverse coloplasty, colonic J-pouch, taeniectomy pouch, or smooth muscle plasty, with or without greater omentum transplantation). Eligible patients had histologically confirmed, well- or moderately-differentiated adenocarcinoma located 1-6 cm from the anal verge. Propensity score adjustment was applied during analysis to minimize residual confounding. The primary endpoint was the incidence of major Low Anterior Resection Syndrome (LARS; score >30), assessed by validated questionnaires at 6 weeks, 3, 6, 12, and 24 months postoperatively. Secondary outcomes included stool frequency, continence recovery, and quality-of-life scores. Trial registration: [AMG-HOSP-RCT-2018-003]. Results: At six weeks, major LARS occurred in 10% of the test group (95% CI: 4-23%) versus 80% of controls (95% CI: 68-88%) (P < 0.001). Mild LARS (score <20) was observed in 80% of test patients compared to 5% of controls. Stool frequency improved from 4.5/day to 2.7/day within 12 months in the test group, consistently outperforming controls. Major incontinence was recorded in 10% (95% CI: 4-23%) of test patients versus 80% (95% CI: 68-88%) of controls. GOT combined with TP or SMP achieved the most favorable outcomes, with faster recovery of anal function and greater LARS score improvement at six weeks post-surgery. Pairwise comparisons confirmed significantly lower stool frequency in both test subgroups at all follow-up points (mean differences -1.8 to -0.4 without GOT; -2.2 to -0.6 with GOT; all P<0.0056). Logistic regression identified test group allocation and GOT as strong independent predictors of reduced major LARS, while prior CRT was the most significant risk factor. Conclusion: GOT and other advanced techniques effectively mitigate LARS severity, resulting in enhanced postoperative quality of life. This study demonstrates the potential benefits of neorectal reservoir techniques and GOT in enhancing functional outcomes after TME for very low rectal cancer. The findings provide promising evidence supporting their role in LARS management; however, broader adoption requires validation in larger, multicenter trials with longer follow-up.