The mathematical basis of adjunctive techniques for enhancement of vessel caliber to maximize coupler ring size for...

The use of ring-pin devices as a nonsuture alternative for microanastomoses is expedient and highly practical, with excellent patency rates. A frequently encountered problem, though, is a significant discrepancy between the donor and recipient vessel lumen size. Rather than accepting the choice of a smaller ring size corresponding to the caliber of the smaller vessel, it may be preferable to instead increase the latter's circumference for potential eversion on the pins by either beveling or "fish-mouthing" the end of the vessel. Arithmetical calculations suggest that a 25% increase in dimensions can thereby be possible at least for thin-walled venous structures. Not only does the capability for selection of a size larger ring simplify drawing the vessel wall through the ring orifice prior to pin impalement, but the resulting larger anastomotic lumen should theoretically increase the potential flow rate across the microanastomosis.