The Prognosis of Preganglionic Brachial Plexus Injuries by Electrodiagnosis

ABSTRACT

OBJECTIVE: To document the neurological recovery of the preganglionic lesion of brachial plexus, both clinically and electrodiagnostically. METHOD: Sixteen male and three female patients were evaluated. Ages of the patients ranged from 1 to 45 years with the mean age of 25.2+/-14.3 years. We studied retrospectively the improvements of 43 injured nerves and its innervated muscles of 19 patients retrospectively according to the complete or incomplete nature of the injuries by the electromyographic findings. We compred the results of initial and final examinations by the electromyographic and clinical findings including a muscle strength test. RESULTS: In the complete injuries, 84.0% of the cases showed a minimal or no improvement in muscle strength whereas in the incomplete injuries, 88.2% of the cases showed a greater than moderate improvement in muscle strength. The cases in which no compound muscle action potential could be evoked on the initial study, showed the improvements of greater than 3/5 muscle strength only in 20.0%. However 71.5% of cases with the initial amplitude between 0.1 & 0.5 mV and 100.0% of cases with the initial amplitude greater than 0.5 mV showed the muscle strength greater than 3/5. CONCLUSION: The prognosis for the neurological recovery was significantly poor in the complete preganglionic lesions of brachial plexus injuries but in the incomplete lesions, the prognosis was extremely good. It would be crucial for the initial CMAP being greater than 0.5 mV to expect the recovery of muscle strength to the functional level. Rehabilitative or operative management should be instituted based on the electrodiagnostic findings.