role of cervical paraspinal electromyography in cervical spinal root avulsions and its correlations with intra operative findings

Abstract

The diagnosis of cervical spinal root avulsion in patients with brachial plexus injuries is major challenge of the present day with the available investigatory procedures. To validate the use of the paraspinal electromyography was done in20 successive patients who all had sustained injuries to their upper limb nerves following road traffic accidents. Electromyographic abnormalities indicative of root avulsion were identified. All of them underwent explorative surgery. The results of the paraspinal electromyography were correlated with the intra-operative findings. Paraspinal electromyography was abnormal in six and normal in 14. All the six patients with abnormal results had evidence of multiple spinal root avulsion. Among those with normal paraspinal electromyography, two showed single spinal root avulsion and in the remaining 12 they were intact. The sensitivity of this test was 75% specificity 100% positive predictive value 100% and negative predictive value 85%. Paraspinal electromyography is an useful test in identifying cervical root avulsions because of its high positive predictive value. However with single root avulsion the sensitivity of the test falls. Somato sensory evoked potential and magnetic resonance imaging studies may be valuable adjuncts in diagnosing such cases.