Changes in the stress relaxation properties of peripheral nerves after transection.

Changes in peripheral nerve stress relaxation after transection were measured weekly for 5 weeks in the distal stumps of sciatic nerves of 50 Sprague-Dawley rats. Each week after transection the distal stumps of the transected nerves showed decreased stress relaxation compared with the freshly transected contralateral nerves after undergoing a 10% elongation. The transected side always showed less stress relaxation at 30 minutes than the intact contralateral side (average, 24%; range, 15% to 32%). A statistically significant difference in mean stress relaxation between the cut nerves and the uncut sciatic nerves occurred for weeks 1 through 4. Week 5 demonstrated a decrease in mean stress relaxation of the experimental side compared with the contralateral control side but this was not statistically significant. Decreased stress relaxation of the distal stump results in increased tension at the suture line as the nerve gap is overcome when performing a delayed neurorrhaphy at 1 to 5 weeks after transection.