Short- and Long-term Outcomes of Three-Row Versus Two-Row Circular Staplers for Low Colorectal Anastomosis After Total Mesorectal Excision: A Single-Center, Randomized, Single-Blind, Phase III Trial (THREESTAPLER Study).

BACKGROUND: Anastomotic leakage remains a critical complication in colorectal surgery. OBJECTIVE: This study compared the efficacy of three-row versus two-row circular staplers in reducing anastomotic leakage rates. DESIGN: Prospective, randomized, single-center, non-inferiority trial. SETTINGS: Clinic of Colorectal and Minimally Invasive Surgery, University Hospital Nº 2, Sechenov University. PATIENTS: The trial included patients who underwent low anterior resection with total mesorectal excision. INTERVENTIONS: Patients were randomized 1:1 to 2-row or 3-row stapler group using centralized, computer-generated randomization. Outcome adjudicators, data collectors, and data analysts were blinded. MAIN OUTCOME MEASURES: Anastomotic leakage incidence; intra- and postoperative anastomotic bleeding; 30-day complications; low anterior resection syndrome; anastomotic stenosis; adverse events; time to and permanence of stoma; and 5-year overall survival. RESULTS: Among 154 patients included in the study, the anastomotic leakage rate was 16.9% (13/77) in the 3-row group compared to 15.6% (12/77) in the 2-row group (p = 0.8). The observed difference between groups was 1.3%, with a one-sided 95% confidence interval bounded below by -8.47%. The rates of anastomotic stricture were 1.4% (n = 2) in the two-row group and 0.7% (n = 1) in the 3-row group (p = 1). No patients experienced anastomotic hemorrhage. Stoma closure was successfully performed in 147 patients (95.5%). The 5-year overall survival was 80.2% (95% confidence interval, 69.4-92.8) in the 3-row group versus 83.8% (95% confidence interval, 75.6-92.3) in the 2-row group (p = 0.80). LIMITATIONS: Routine postoperative proctography was not performed, clinically silent (Grade A) leaks may have been missed; the study was underpowered because the assumed 12% anastomotic leakage difference for sample-size estimation was optimistic; neoadjuvant regimen heterogeneity may have influenced outcomes; and the single-center design may limit generalizability. CONCLUSIONS: The three-row stapler was not non-inferior to the 2-row stapler in preventing anastomotic leakage. See Video Abstract.Clinical trial registration number: NCT03910699.