Modified Kunlin's Technique for Microsurgical End-to-End Anastomoses: A Series of 100 Flaps

Background In 1949, a French vascular surgeon, Jean Kunlin, first described a venous end-to-side anastomotic technique to address large vessel size mismatches. It was later modified by Dr. Robert Linton for end-to-end (ETE) anastomoses on the macrovascular scale. While multiple procedures exist for addressing moderate caliber discrepancies, few safely and reliably compensate for marked diameter differences at the microvascular level. In this study, we present the first large series adapting a modified geometric Kunlin's technique for arterial and venous ETE anastomoses in reconstructive microsurgery. Methods We reviewed 100 consecutive cases of free flap reconstructions from 2006 to 2015 utilizing a modified geometric Kunlin's technique for arterial and venous ETE anastomoses. Patient demographics and flap outcomes were analyzed. Overall flap survival rates and postoperative complications were analyzed and compared with standard values in the microsurgical literature. Results A total of 146 ETE anastomoses from 100 free flaps were analyzed. The average patient age was 51 ± 3.1 years (range: 10-84 years). Free flaps in this study were used for gender confirmation phalloplasties (20%) and reconstructing defects of the head and neck (63%), extremities (16%), and trunk (1%). There was a total of 17 takebacks including 5 for hematoma, 8 for anastomotic thromboses (6 venous), and 4 without any identifiable complication. Of these takebacks, two partial and two complete flap losses occurred. There was an 88% salvage rate for flaps requiring takebacks during the postoperative period. Overall, flap survival rate was 98% including those with complications or takebacks. Conclusion The modified Kunlin's technique is a reliable, facile, and versatile method of performing ETE anastomoses for arterial and venous vessels, especially with vessel diameter mismatches of 3:1 or greater, as well as for challenging orientations. Notably, it provides equivalent flap survival and complication rates as compared with other techniques in the microsurgical literature.