AIM: Splenic flexure resection (SFR) is a technically demanding procedure due to the region’s complex vascular anatomy and limited colonic mobility. The orientation of the colonic anastomosis—either isoperistaltic or anisoperistaltic—represents a critical yet understudied technical factor that may influence operative complexity and postoperative recovery. This study aimed to compare short-term outcomes between these two anastomotic configurations.

METHODS: We conducted a retrospective cohort study at a tertiary colorectal center, including consecutive patients who underwent elective SFR for colon cancer between January 2023 and December 2024 (n = 53). Patients were stratified according to the orientation of the side-to-side anastomosis: isoperistaltic (ISO, n = 32) or anisoperistaltic (ANISO, n = 21). Demographic, oncologic, surgical, and postoperative variables were analyzed. Primary endpoints were operative time, gastrointestinal recovery (time to first flatus and first stool), and length of hospital stay. Secondary endpoints included estimated blood loss, conversion rate, 30-day complications, inflammatory markers, analgesic use, costs, and quality of life assessed using the Gastrointestinal Quality of Life Index (GIQLI).

RESULTS: Baseline demographics were largely comparable between groups, although patients in the ANISO group were significantly older (71.4 ± 6.0 vs. 67.8 ± 4.4 years; p = 0.023) and had a slightly lower body mass index (BMI) (25.4 ± 1.4 vs. 26.5 ± 2.3 kg/m²; p = 0.049). Operative time was significantly shorter in the ANISO group (126.5 ± 13.8 vs. 154.8 ± 23.4 minutes; p < 0.001). Gastrointestinal recovery was faster following anisoperistaltic anastomosis, with earlier first flatus (31.7 ± 8.7 vs. 39.3 ± 10.2 hours; p = 0.005), while time to first stool did not differ significantly (51.2 ± 12.5 vs. 55.8 ± 9.0 hours; p = 0.159). Length of hospital stay was comparable (5.2 ± 0.8 vs. 5.6 ± 1.3 days; p = 0.172). Estimated blood loss was significantly lower in the ANISO group (34.6 ± 17.0 vs. 47.6 ± 13.6 mL; p = 0.006). Conversion rate and postoperative complications were comparable between groups (p = 1.000 and p = 0.743 respectively). No differences were observed in inflammatory markers, analgesic use, or costs. GIQLI scores at 30 days were similar between groups (126.9 ± 11.0 vs. 123.0 ± 8.1; p = 0.166).

CONCLUSIONS: Anisoperistaltic anastomosis following splenic flexure resection is safe and effective and is associated with shorter operative time and faster postoperative gastrointestinal recovery without compromising short-term outcomes. The choice of anastomotic orientation may be influenced by intraoperative anatomical conditions and technical factors.