Diagnosis of the vertebral level from which low back or leg pain originates. A comparison of clinical evaluation, MRI and epiduroscopy.

BACKGROUND: The precise localization of painful structures in the spine of patients with low back pain and/or pain radiating (LBP/RP) to the lower extremities is important for targeted therapeutic intervention. The aim of the study reported here was to determine and compare the spinal segment(s) where pain was elicited via endoscopic evaluation vs. the vertebral level from where the pain was thought to originate as determined by clinical evaluation and by MRI.

METHODS: Observational cohort study of 143 patients 19 to 88 years of age undergoing spinal canal endoscopy (epiduroscopy) in a combined academic and private practice setting January 2008 to December 2008. Patients were asked whether pain generated by pressure upon epidural structures with the tip of an endoscope was similar in character and distribution (concordant) to the pain for which patients sought treatment. Notes from clinical evaluation and MRI reports were reviewed, and segmental level determined to be the locus of pathology was tabulated.

RESULTS: One hundred twenty-five (87%) patients reported maximal reproducible pain at a specific level during epiduroscopy. The most common level was at L4 to L5 (87 patients). The least common level was L5 to S1 (2 patients). In only 40 patients did the level determined by clinical evaluation correlate with the level at which pain could be reproduced during epiduroscopy. MRI indicated a specific vertebral level that corresponded to the level at which pain could be reproduced during epiduroscopy in 28 of 143 (20%) patients. The results of the 3 diagnostic methods were significantly different (P < 0.01).

CONCLUSION: Results of this study indicate that epiduroscopy is more reliable than is either clinical evaluation or MRI for determining the vertebral level where clinically significant spinal pathology occurs in patients with LBP/RP.