[Advantages and limitations of electroneuromyography for analysis of upper limb pain]

To study the utility of electroneuromyography in analysis of upper limb pain as a function of the existence of a diagnostic hypothesis.

We retrospectively compared the consecutive electroneuromyographic examinations performed between 1 January and 30 September 2004. All recordings were performed by the same examiner in the neurophysiology clinic in the department of neurology of Saint-Etienne university hospital UHC at the request of hospital specialists or surgeon and private general practitioners. In each examination, at a minimum and regardless of the specific situation, motor conduction speed, F waves, and sensory conduction speed were recorded for the median nerve and the ulnar nerve on the right and left. For the arm in question, needle electromyography explored the muscles depending on the C5-T1 roots.

In all, 76 patients had ENMG examinations, 38 for whom the physician had a diagnostic hypothesis and 38 patients without. In the case of a diagnosis based on clinical suspicions, examination was normal in 73.7% of cases compared with 23.7% when there was a clinically based hypothesis (p<0.01). These findings did not vary significantly according to the specialization of the referring physician.

Electromyography and nerve conduction studies are useful to confirm a diagnosis based on patient reports and clinical data, it is not useful when no diagnosis has been suggested.