To describe neurophysiological changes over time in persons with and without spinal complaints, and to assess whether paraspinal denervation predicts change in stenosis on MRI and clinical course.
Prospective, controlled, masked trial.
University spine program.
Persons aged 55–80, screened for polyneuropathy and determined on clinical examination to have spinal stenosis, mechanical low back pain, or no spinal symptoms.
Subjects underwent comprehensive codified history and physical examination, ambulation testing, masked electrodiagnostic testing including paraspinal mapping, and MRI; repeated at >18 months. This publication presents detailed technical information and additional analyses not reported previously.
Main Outcome Measurements
Change in electrodiagnostic findings. Among persons with clinical stenosis, relationship of change in paraspinal mapping scores to MRI findings and clinical changes.
Of 149 initial subjects, 83 (79.3% of eligible subjects) repeated testing at 20 +/− 2 s.d.) months. No significant change in limb muscle spontaneous activity or motor unit pathology was noted in any group. In 23 persons with initial diagnosis of stenosis, paraspinal mapping EMG related to change in diagnosis over time (ANOVA F=3.77, p=0.037), but not to most initial MRI measurements or to change in spinal canal diameter.
Clinical spinal stenosis is neurophysiologically stable in most persons. Paraspinal EMG changes reflect large changes in clinical course, but neither neurophysiological nor clinical changes relate to change in spinal geometry over 20 months.