876 - Evaluation of Patient’s Self-Report of Percent Change Compared to Calculated Numerical Rating Scale Score Changes Among Pre-and-Post Medial Branch Block injections.

Objectives: The 80% threshold improvement established by the Centers of Medicare and Medicaid Services (CMS) for medial branch block positivity has created some challenges for patients that have difficulty with ascribing a numerical value to their pain. Our objective is to compare the calculated reduction in pain using NRS with the patient's self-reported estimate of percentage reduction in pain and satisfaction score after diagnostic medial branch blocks.

Design: An observational study of patients undergoing medial branch block injections (MBB), with participants completing a pre-and post medial branch block survey. The setting consisted of all patients receiving MBB injections within an academic multi-center clinic system.IRB approval was obtained before data collection began.

Results: Of 112 patients receiving MBB injections, 67 patients (59.9%) met the threshold criteria of 80% or higher in their pain improvement. Among patients meeting threshold criteria, an average NRS score percent change was 87.03%. Higher satisfaction scores were significantly associated with higher percent change between pre and post MBB (p< 0.0001, CI -69.68-59.02). Across all patient grouping, percent change of reported pain scores compared to calculated pain scores was statistically significant (p=0.011).

Conclusions: Pain outcome scores were truly reflected among patients who met threshold criteria of 80% or higher in pain improvement following MBB injections. High satisfaction scores were observed among patients with higher percent change in pre and post procedure self-report of pain.