Comparison of a Novel Intracorporeal Anastomosis Versus Extracorporeal Anastomosis for Colon Cancer: A Propensity Score-Weighted, Prospective Idea, Development, Exploration, Assessment, Long-term Stage 2b Cohort Study

BACKGROUND: Intracorporeal anastomosis benefits are often offset by high costs and technical complexity. OBJECTIVE: To evaluate the safety, efficacy, and cost-neutrality of a novel U-tied functional end-to-end anastomosis v. conventional laparoscopic-assisted colectomy. DESIGN: Prospective cohort study following the Idea, Development, Exploration, Assessment, Long-term follow-up Stage 2b framework, using inverse probability of treatment weighting. SETTINGS: Single tertiary referral hospital. PATIENTS: Patients undergoing elective radical colectomy for colon cancer (May 2023 to December 2025). INTERVENTIONS: Intracorporeal U-tied functional end-to-end anastomosis v. conventional extracorporeal anastomosis. MAIN OUTCOME MEASURES: Overall 30-day postoperative complications, operative metrics, recovery indicators, postoperative pain, and hospital costs. RESULTS: Of 461 patients, 294 underwent extracorporeal and 167 received U-tied anastomosis. After weighting, baseline covariates were balanced. Thirty-day complication rates were comparable between U-tied and conventional groups (10.8 vs 11.3%, p = 0.907), a finding consistently supported by sensitivity analyses (all p > 0.05). However, this nonsignificant result should be interpreted cautiously as absence of evidence to detect a difference. Although the U-tied required longer anastomosis time (27.4 vs 22.4 min, p < 0.001), total operative times were comparable ( p = 0.172). The U-tied group showed significant advantages in shorter incisions (4.3 vs 8.9 cm), reduced blood loss, and earlier return of bowel function (flatus: 60.8 vs 80.4 hours; defecation: 73.9 vs 87.0 hours; all p < 0.001). Visual analogue scale (VAS) scores were significantly lower in the U-tied group on Pod 1 ( p < 0.001). Limitations: Single-center design and limited statistical power for rare complications. CONCLUSIONS: The U-tied functional end-to-end anastomosis is a safe, feasible, and cost-neutral intracorporeal technique that reduces surgical trauma, alleviates early pain, and accelerates recovery. See Video Abstract.