The optimal number and location of sutures in conduit-assisted primary digital nerve repair.

We evaluated the strength of conduit-assisted primary digital nerve repairs, with varying suture location and number, in 56 digital nerves from cadavers. Maximum load to failure was tested for the following seven repairs, designated by the number of epineurial sutures followed by the number of sutures at each end of the conduit: 4 (epineurial sutures)/0 (sutures at each end of conduit), 4/4, 4/2, 2/2, 0/4, 0/2, 0/1. The 4/4 repair (3.0 N) was significantly stronger than 4/0 (1.5 N), 2/2 (1.6 N), 0/4 (2.0 N), 0/2 (1.4 N) and 0/1 (1.1 N). Considering all repair types, there was a significant correlation between suture number and failure load, with the strongest repair having a total of 12 sutures, which is impractical. Reasonable repair options, which have two sutures at each end of the conduit and either two or no epineurial sutures, are as strong as a four-suture epineurial repair but have less sutures at the coaptation site.