Peripheral nervous system involvement in chronic spinal cord injury.

Abstract

Upper motor neuron disorders are believed to leave the peripheral nervous system (PNS) intact. In this study we examined whether there is evidence of PNS involvement in spinal cord injury (SCI). Twelve subjects with chronic low cervical or thoracic SCI were included prospectively. Needle electromyography was done in 10 different muscles in each subject bilaterally. Nerve conduction studies (NCS) were conducted in the fibular, tibial, and femoral motor and fibular and sural sensory nerves. Half the subjects had widespread abnormal spontaneous activity (SA), and the amount of SA correlated inversely with reflex activity and nerve length. Fibular nerve entrapment across the knee was seen in 6 subjects, and sciatic nerve entrapment was seen in 1. Apart from entrapment neuropathies, NCS changes were found predominantly in motor nerves. The presence of widespread electrophysiologic changes outside entrapment sites indicates that SCI has a significant impact on the entire PNS, affecting the motor part predominantly.