Prolongation of greater occipital neural blockade with 10% lidocaine neurolysis: a case series of a new technique

INTRODUCTION Greater occipital nerve blocks (GONB) have been used for headache but their benefit may be short. Ready et al performed intrathecal injections on rabbits and reported neurologic/histologic changes that required concentrations of at least 8%. Our study tests the hypothesis that the neurolytic effects of GONB with 10% lidocaine can prolong relief. METHODS After an approval from Henry Ford Hospital Institutional Review Board, a chart review was performed for patients who had GONB with 10% lidocaine. Patients received 10% lidocaine after short response (<1 month / >50% relief) to GONB with 1 cc of a solution containing 9 mL 0.5 % bupivacaine and 40 mg methylprednisolone. They received a block with 10% lidocaine with volume given at <80% of the maximum dose of 4 mg/kg. Injections were performed under fluoroscopic guidance after injection of 0.1 cc of contrast (isovue or magnevist). All patients had intravenous access and were given fentanyl and midazolam. The visual analog scale (VAS) scores were recorded on follow-up, and the duration of response was noted. VAS changes with 10% lidocaine and comparison of duration with methylprednisolone were performed using paired t-test. RESULTS Thirteen patients were reviewed; 12 were female and the mean age was 47. Ten were diagnosed with migraine, and three with occipital neuralgia; 12 had bilateral symptoms. Baseline VAS prior to 10% lidocaine averaged 86.92 mm. The mean volume injected per nerve was 1.096 mL. There was significant decrease in mean% VAS with 10% lidocaine at 60.4% (mean: -52.69 mm) (P=0.001). The mean duration of relief was significantly higher with 10% lidocaine at 148.05 days ([standard deviation]=98.87) versus methylprednisolone at 6.33 days (standard deviation=5.01) (P=0.001). No complications or side effects were reported. CONCLUSION Ten percent lidocaine may be a useful neurolytic agent in prolonging the duration of GONB.