Prolongation of Lumbar Facet Joint Nerve Block Duration with 10% Lidocaine Neurolysis: A Retrospective Cohort Study

Background: Neural blockade of the facet medialbranch/L5 dorsal rami with local anestheticwith or without corticosteroid has been used toboth diagnose and treat low back pain. Higherconcentration lidocaine has been shown to beneurolytic in multiple in vivo, in vitro, and someclinical studies. This may make 10% lidocaine apossible neurolytic agent to prolong pain relieffrom facet blocks.Objective: Compare neurolytic effects of 10%lidocaine to prolong pain relief compared to bupivacaine/methylprednisolone (BM) in facet medialbranch/L5 dorsal rami blocks (MBB).Methods: Retrospective review of 77 patientswho received a 10% lidocaine MBB from aftershort term relief from MBB with BM. Comparisonwas made in visual analog scale (VAS) and durationof relief using Wilcoxon signed rank matchedpairs test.Results: There was no significant differencebetween baseline median VAS prior to MBB withBM and 10% lidocaine and median days VASrecorded post each MBB ((P = 0.477). MedianVAS immediately after BM MBB (17.5 mm) wasnot significantly different than after 10% LidocaineMBB) of 18 mm (P = 0.341). Median duration ofrelief with 10% lidocaine was greater at 14 daysversus BM at 3.5 days (P = 0.001). There wasno significant correlation between the volumeof 10% lidocaine at each level and performancemeasures: % change VAS post lidocaine MBB (P=0.529), duration lidocaine MBB (P = 935), VASpre-RFTC (P = 0.683).Limitation: Retrospective, small study.Conclusion: Ten percent lidocaine was moderatelyeffective neurolytic agent with longer durationthan BM.Key words: Lidocaine, facet joint, neurolysis,low back pain