Changes in electromyographic results of patients with lumbar radiculopathy: a follow-up study.

OBJECTIVE: To assess the neurophysiologic changes in a group of patients with lumbar radiculopathy 5 to 12 months after their first electromyographic examination. DESIGN: A prospective group of patients with a case definition of lumbar radiculopathy was reassessed between 5 and 12 months after their first clinical, functional, imaging, and neurophysiologic evaluation. Both the lumbar paraspinals (in which the mini-mapping technique was used) and the same lower limb muscles were explored in every patient. Relevant abnormalities were (1) positive sharp waves/fibrillation potentials, (2) polyphasic motor unit potentials, and (3) large-amplitude/long-duration motor unit potentials. Patients were sorted into 5 groups based on the type and distribution of neurophysiologic abnormalities: from 0 (no abnormalities) to 4 (denervation signs in 2 lower limb muscles and paraspinals). Patients' subjective perception of any improvement or worsening of their condition was also recorded. SETTING: A referral center for neurophysiologic evaluation. PARTICIPANTS: A consecutive sample of patients (N=91) with a clinical definition of lumbar radiculopathy (lumbar pain radiating down the leg and below the knee) referred for neurophysiologic assessment was selected for an initial clinical, functional, and neurophysiologic evaluation. Patients were called for a second evaluation (between 5 and 12mo). Thirty-eight (42% of the initial sample) were willing/eligible for the second evaluation. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Changes in (1) electromyographic results; (2) patients' subjective perception of pain; and (3) quality of life, based on the Roland-Morris Questionnaire and Medical Outcomes Study 36-Item Short-Form Health Survey scores. RESULTS: Paraspinal muscles were most frequently affected. Neurophysiologic abnormalities had improved on reassessment. Clinical improvement was more significant for those patients with initially abnormal electromyographic results. CONCLUSIONS: There was clinical as well as electromyographic improvement in patients with lumbar radiculopathy within the first year of the initial diagnosis.