Measurement of reduction in pain as reported by patients aged 18 years and older following medial branch radiofrequency ablation 1. The percent reduction in pain score on a visual analog scale (0-10), comparing pre-procedure pain (recorded within 90 days prior to the procedure) and post-procedure pain (recorded within 120 days following the procedure) in the area targeted for treatment 2. The reduction in pain as reported by the patient as a percent reduction in pain in the area targeted for treatment, comparing pre-procedure and post-procedure pain. Percent reduction in pain must be reported within 120 days following the procedure. Performance rate: 2 (cervical/thoracic, lumbar/sacral)