Electrophysiologic assessment of shoulder girdle weakness in patients with cervical spondylosis: prognostic value of supraclavicular stimulation.

OBJECTIVES

We tested the use of supraclavicular stimulation as a prognostic measure of deltoid function after cervical spondylotic radiculopathy.

METHODS

Electrophysiological study consisted of supramaximally stimulating the brachial plexus and recording compound muscle action potentials (CMAPs) from the deltoid in 32 patients with unilateral weakness of 3 months or shorter duration as compared with 69 healthy subjects.

RESULTS

Despite considerable individual variability and age-related reduction in amplitude and area of deltoid CMAPs, the side-to-side ratios yielded useful, reproducible values. The measures recorded initially correlated significantly with the eventual recovery of deltoid strength but, interestingly, not with the initial degree of weakness. In particular, the CMAPs greater than 50%, even in the face of severe weakness, predicted a nearly complete return of function.

CONCLUSIONS

Supraclavicular stimulation provides a useful measure in monitoring deltoid weakness and predicting its recovery in patients with cervical spondylosis.