Electrodiagnostic evidence for cervical radiculopathy and suprascapular neuropathy in shoulder pain

Abstract

Patients diagnosed with a shoulder impingement syndrome occasionally do not respond to techniques used for treatment of soft tissue injury. The neurologic examination may be only partially abnormal or incomplete due to pain limitation so that peripheral nerve or nerve root abnormalities are overlooked. This study was undertaken to investigate the frequency of cervical radiculopathy and suprascapular neuropathy in patients with shoulder pain who were initially diagnosed with a musculoskeletal syndrome. Thirty-three subjects with a diagnosis of unilateral or bilateral impingement syndrome were entered into the study. A neurological examination was performed, followed by electromyography on 38 upper extremities and associated cervical paraspinal muscles to search for electrodiagnostic evidence for a suprascapular neuropathy and/or cervical radiculopathy. There were no subjects with electrodiagnostic evidence for suprascapular neuropathy. In two studies (5.3%), there was electrodiagnostic evidence for a C5/6 radiculopathy, and in nine (23.7%) additional subjects, there was electrodiagnostic evidence for a possible cervical radiculopathy. The remaining 27 (71.1%) studies showed no significant electrodiagnostic evidence for a cervical radiculopathy. Of the 11 subjects with abnormal electrodiagnostic studies, the neurological examination in 7 (63.6%) was normal except for pain-limited manual muscle testing, and the other 4 (36.4%) had an abnormality in either sensation testing, muscle bulk, or muscle stretch reflexes. One case of a patient with an initial diagnosis of soft tissue injury is presented. In patients undergoing evaluation for shoulder pain, cervical radiculopathy as a possible etiology should be considered, even when there is an equivocal clinical examination.