CLINICAL-EXPERIENCE WITH PARASPINAL MAPPING .1. NEUROPHYSIOLOGY OF THE PARASPINAL MUSCLES IN VARIOUS SPINAL-DISORDERS

Objective: To assess the extent of denervation of the paraspinal muscl es in spinal disorders. Design: Nonrandomized prospective trial. Setti ng: Electrodiagnostic laboratory of a university spine center and of a private practice in a small community. Subjects: One hundred fourteen consecutive persons referred for electrodiagnosis of spinal or lower extremity disorders. Intervention: The paraspinal mapping (PM) electro myography (EMG) protocol along with codified history, physical examina tion, extremity EMG, and in 44 cases, radiologic imaging results. Main Outcome Measures: PM scores compared with recently established norms (95% of normal subjects scoring less than <6), lower extremity (LE) EM G findings, and imaging results. Results: Fifty-eight subjects had nor mal PM scores; 62 were abnormal. Compared to imaging studies, false po sitive rate was 8% (1/13). False negative rate (normal PM with definit e nerve involvement on imaging) was 33% (6/18), but this decreased to 5% when PM was combined with LE EMG. Four of 4 high lumbar lesions wer e detected by PM. Of 14 apparent false negatives (13%) compared to LE EMG, 6 had S1 root lesions and 5 had nonspinal lesions. All 7 subjects with isolated S1 radiculopathy had PM scores within normal limits. Oc casional polyneuropathies presented with normal PM and abnormal distal findings or with abnormal PM but normal distal findings. No patient w ith isolated paraspinal findings had evidence of malignancy on follow- up. This report also describes the distribution of denervation in the multifidus, longissimus, and iliocostalis in various disorders. Conclu sions: PM relates well to imaging studies and LE EMG. It detects uncom mon high lumbar root lesions. S1 may not innervate the paraspinal musc les. There are isolated paraspinal findings in persons without maligna ncy. The effects of specific muscle denervation on biomechanics, rehab ilitation exercise, and prognosis are not known. (C) 1997 by the Ameri can Congress of Rehabilitation Rehabilitation Medicine and the America n Academy of Physical Medicine and Rehabilitation.