Factors that affect the efficacy of fluoroscopically guided selective spinal nerve root block in the treatment of radicular pain: a prospective cohort study.

Aim: The fluoroscopically guided selective nerve root block (SNRB) is being used increasingly as a therapy for radicular pain as well as a diagnostic tool. However, studies and the literature reviews have yet to reach a definite conclusion on the efficacy in this setting. Our aim was to prospectively investigate factors that may affect the success of this procedure.

Materials And Methods: A total of 301 treatment episodes with 283 patients were assessed over 25 months by patient questionnaire over a 7-day period. Changes in analgesic benefit over time, by operating consultant, referring specialty, spinal level, and the presence of periprocedural symptom provocation were evaluated. Statistical analysis was performed by using the χ(2) test, Wilcoxon test, and Kruskal-Wallis rank sum test, and the asymptotic marginal-homogeneity test. P < .05 was considered significant.

Results: There was a statistically significant increase in pain relief over the 7 days after the procedure. Pain provocation during the procedure did not improve analgesic success. Cervical, lumbar, and sacral level procedures were equally efficacious. The specialist who referred the patient and the use of contrast to verify needle position during the procedure also did not affect the analgesic outcome. Overall, 69.1% of patients experienced some pain relief by day 7.

Conclusion: Analgesic success rates of selective nerve root blocks did not vary with spinal level, or use of contrast or periprocedural replication of symptoms, when using fluoroscopic guidance. Patients may expect a continued significant improvement in their symptoms for at least a week after the procedure.