Correlation of Lumbar Medial Branch Neurotomy Results with Diagnostic Medial Branch Block Cutoff Values to Optimize Therapeutic Outcome

Objective. We sought an optimal medial branch block (MBB) cutoff value for both single and double MBB protocols that would best correlate with a positive outcome of medial branch neurotomy (MBN). Outcome Measures. We analyzed the percentage of subjective pain relief following MBB, confirmed by numerical rating scale (NRS) in aggravating positions before and 45 minutes after MBB. The percentage of overall pain relief following MBB was plotted against the following outcome variables: degree of subjective pain relief, duration of relief, patient satisfaction and activity level, no other doctor's visits, and reduction in medications use. Results. Using the percent of pain relief post-MBB plotted in 10% increments in the double-MBB group, patients reporting 70% or greater pain relief following MBB showed statistically favorable outcome for the following four criteria: percentage of pain relief, duration of relief, patient satisfaction, and pain medications reduction. In the single MBB group, patients reporting 80% or greater pain relief following MBB had favorable outcomes for improvement in activity level and patient satisfaction. Conclusions. The double MBB protocol better correlated with favorable MBN outcomes compared with a single MBB protocol. Using a double MBB protocol, a 70% cutoff value for reported subjective pain relief post-MBB best predicted overall outcome following MBN. Without a confirmatory MBB, an 80% cutoff value was the optimal value.