fig1

Figure 1. Rule-of-thumb calculation for predicting outcomes after neurorrhaphy. Assuming that axonal regeneration occurs at a rate of 2.5 cm per month and that the neuromuscular junction will remain intact for 18 months, favorable neurorrhaphies are those in which the distance between the injury site to the muscle target is less than 45 - 2.5x in centimeters, where x is the number of months since injury. In example 1, primary repair at 6 months after high sciatic nerve injury is unfavorable and nerve transfers should be considered. In example 2, primary repair at 9 months of a low sciatic nerve injury is favorable.