Identification of cervical radiculopathies - Optimizing the electromyographic screen

Objective: To determine the optimal electromyography screening examination of the upper limb that ensures detection of those cervical radiculopathies, which can be electrodiagnostically confirmed, yet minimizes the number of muscles studied. Design: A prospective multicenter study was conducted from May 1996 to Sept ember 1997 at five institutions. Patients who were referred to participatin g electrodiagnostic laboratories with suspected cervical radiculopathy were recruited. A standard set of muscles were examined by needle electromyogra phy. Patients with electrodiagnostically confirmed cervical radiculopathies , based on electromyography findings, were selected for analysis. Muscle sc reens were tested against this group to determine whether the screen identi fied the patients with radiculopathy. Results: There were 101 patients with cervical radiculopathies representing ail cervical root levels. When paraspinal muscles were one of the screenin g muscles, five muscle screens identified 90% to 98% of radiculopathies, si x muscle screens identified 94% to 99%, and seven muscle screens identified 96% to 100%. When paraspinal muscles were not part of the screen, eight di stal limb muscles recognized 92% to 95% of radiculopathies. Conclusion: This study demonstrated that six muscle screens including paras pinal muscles yielded consistently high identification rates. Studying addi tional muscles led to marginal increases in identification.