Enhancing microvascular anastomoses with the Synovis Coupler device: A retrospective analysis of management of vascular diameter discrepancies

Background and Introduction: Microvascular surgery enables com- plex tissue repairs with free flaps. The Synovis Coupler has stream- lined venous anastomoses, improving speed and precision. How- ever, size discrepancies between donor and recipient vessels con- tinue to cause postoperative complications. This study presents our experience in managing caliber discrepancies, optimizing venous flow, reducing thrombosis risk, and improving free flap survival. Material and Methods: This retrospective observational study an- alyzed data from patients undergoing free flap reconstruction be- tween January 2018 and January 2024. A total of 84 microvascular free tissue transfers and 86 venous anastomoses were performed using a mechanical coupler system. Results: Eighty-six venous anastomoses were completed, averag- ing 3.25 min each, with an average coupler size of 2.34 mm. No postoperative returns to the operating room or anastomosis revi- sions were required. Complications included one infection and one hematoma, both resulting in flap necrosis. The average follow-up was 1.7 years, with no cases of venous ischemia. Discussion and Conclusion: Our experience suggests that adapting the vessel lumen may represent a practical option for managing di- ameter discrepancies when using couplers. The approach appeared to reduce the need for grafts and allowed efficient anastomosis. However, the retrospective design, limited sample size, and lack of a comparative group constrain the strength of these findings. Further prospective studies are warranted to confirm whether this method offers a consistent advantage over established techniques.