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

ABSTRACT

INTRODUCTION: A limiting factor in the use of perforators as recipient vessels is the small-to-large diameter mismatch often encountered. Mismatches less than 11.5 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. MATERIALS AND METHODS: 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. RESULTS: 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). CONCLUSIONS: In the management of microarterial size discrepancy between 11.5 and 12.5, an invaginating anastomosis is faster to perform and produces comparable patency in a rat model.