The morphologic characteristics of nerve shortening following traumatic bone loss.

Little is known about peripheral nerve shortening secondary to joint contracture or traumatic bone loss. We used the rat sciatic nerve as a model to study nerve shortening secondary to leg shortening. Nerve shortening was induced by surgically removing 16 mm of the femur. The histology of the ipsilateral and contralateral (control) sciatic nerves were compared at 1 h, 3 weeks, and 6 weeks. Transverse semithin sections of sciatic nerve were prepared and examined; single fibers also were teased from the nerve for study. The epineurium was shortened about 25% at 6 weeks. Axonal diameter was unchanged at 1 h, but increased over time, and was 0.68 microm larger than controls at 6 weeks (p < 0.05). In teased-fiber preparations, internodal length decreased 2.3% at 6 weeks, but not significantly. Peripheral nerve shortening secondary to leg shortening shortens the epineurium, but does not effect on internodal length.