The Role of Electrophysiological Workup in Lumbar Spinal Canal Stenosis (LSCS): A Systematic Review

Study design: Systematic literature review. Objective: Update on diagnostic utility of electrophysiology in lumbar spinal canal stenosis (LSCS). Summary of background: LSCS is a highly prevalent degenerative spine condition characterized by neurogenic claudication, radicular pain, and muscle weakness. While lumbar spine MRI is the imaging modality for detecting spinal canal narrowing, it correlates poorly with clinical symptoms. Electrophysiological methods, including electromyography (EMG), nerve conduction studies (NCS), and evoked potentials (MEP and SEP), may provide complementary information on neural dysfunction. Current guidelines support paraspinal electromyography (EMG) mapping for symptomatic patients with imaging confirmed stenosis (grade B). In contrast, the diagnostic value of other electrophysiologic tests in lumbar spinal canal stenosis (LSCS) remains uncertain. Methods: A systematic literature search was conducted in Medline and Embase for original studies on LSCS between 2020 and 2024. Two independent reviewers screened studies for inclusion. Extracted data was synthesized qualitatively. Study quality was assessed using the Robins-V2 tool. PROSPERO registration (CRD42024622427). Results: Thirteen studies met the inclusion criteria; study quality was moderate. Needle EMG of the limbs was evaluated in 23% of studies to detect denervation as a sign of radiculopathy. 23% of the studies examined tibial nerve SEP or cauda equina MEP conduction time for lesion localization, with varying findings and utility for diagnosing LSCS. Surface EMG was investigated in 31% of studies and revealed significantly altered muscle activation patterns and compensatory gait adaptations in LSCS. Conclusion: There is an increasing number of studies combining surface EMG with gait assessments and tasks. This approach is interesting for being non-invasive with clinical utility to be further determined. Based on previous guidelines, paraspinal mapping is considered the gold-standard electrophysiological diagnostic tool. Interestingly, there were no recent studies on paraspinal mapping, indicating a shift to alternative methods.