Interpositional vein grafting for significant size discrepancy: The important role for short, sequential grafts in step-up and step-down microvascular anastomoses.

Introduction: Anastomotic vessel size discrepancy may be addressed by numerous techniques, including the end-to-side. Most of these conventional methods are less suited with larger flap vessels relative to recipients, such as the vessel-depleted oncological neck with prior radiotherapy or in supermicrosurgical techniques with perforator recipients. We describe how short segment (single or double) interpositional vein grafts can be used to safely graduate this discrepancy in a 'step-up' or 'step-down' manner.

Methods: We conducted a retrospective review of all cases where interpositional vein grafts had been utilised. Furthermore, the technique for harvest, vessel preparation and anastomotic sequence is described.

Results: Over fifteen years, 116 short segment interpositional vein grafts (in 83 patients) were employed to address vessel discrepancy. Concerning patient demographics, there were 81 male:2 female, mean age 51 years (range 27-68 years), and aetiology was oral cancer (75), trauma(7) and congenital(1). Single (50) and double (33) grafts were used for 65 arterial anastomoses (8 step-down: 57 step-up) and 18 for venous anastomoses (12 step-down: 6 step-up). Flaps employed were osteocutaneous fibula (28), anterolateral thigh (24), free ileocolon (11), radial forearm (11), SCIP (7) and others (2). Six flaps (of 83) were lost (5 arterial and 1 venous thrombosis).

Conclusion: Short segment interpositional vein grafts may be safely utilised for 'step-up' and 'step-down' anastomoses. Planned use in the primary case, minimum required length and meticulous preparation are fundamental for success and to dispel traditional concerns over poorer outcomes when vein grafts are used.