Experimental investigation of two techniques of arterial microanastomosis used to manage a small-to-large diameter discrepancy.

Abstract

A limiting factor in the use of perforators as recipient vessels is the small-to-large diameter mismatch often encountered. Mismatches less than 1:1.5 may be managed by dilatation of the smaller vessel and by differentially-spaced suture bites. Beyond this ratio, little evidence exists to direct the choice of end-to-end anastomotic technique. Following in silico work and the characterisation of a rodent superficial caudal epigastric/femoral artery model, we conducted an experimental series examining two techniques - an oblique section of the smaller vessel and invaginating the smaller vessel inside the larger. A paired design was used. To test for a difference in patency of >5% required a total of 156 animals (312 anastomoses). Side and technique were randomised. Two investigators performed the anastomoses. A single revision was permitted. Anastomoses were timed and patency was tested at one hour, one week and at six weeks. There was no significant difference in patency at each of the three time points (p = 0.8026, 0.2963 and 0.8137). The invagination technique was significantly faster to perform (p < 0.0001). There was a significant association between the investigator and both patency and the time taken to complete an anastomosis. Independent of the investigator, a revision was more likely to be necessary with the oblique end-to-end technique, and a revision having been performed showed a highly significant association with an anastomosis having failed at 1 h (p < 0.0001, OR 33.333). In the management of microarterial size discrepancy between 1:1.5 and 1:2.5, an invaginating anastomosis is faster to perform and produces comparable patency in a rat model.