The Neurosurgeons' Armamentarium for the Management of Refractory Post-Herpetic Neuralgia

Abstract

Abstract INTRODUCTION Post-herpetic neuralgia (PHN) can be refractory to medical treatment. Its complex pathophysiology explains the numerous neurosurgical procedures available. The present study summarizes all available neurosurgical strategies for the management of resistant PHN and evaluates respective safety and efficacy. METHODS A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. The PubMed and Cochrane Library databases were searched up to October 2018. RESULTS A total of 38 studies comprising 811 patients with refractory PHN were included. Ten studies with 243 patients reported use of spinal cord stimulation. The mean visual analog scale (VAS) score was 7.6 and 2.7 before and after the procedure. Dorsal root entry zone (DREZ) lesioning was performed in 85 patients. The mean VAS score before and after the procedure was 8.6 and 3.7. During the postoperative period, 42.3% of patients developed motor deficits. Five studies investigated intrathecal (IT) injections or pump insertions. The combined IT injections demonstrated a strong analgesic effect 87% of patients reported pain reduction >50%. Spinal trigeminal nucleotomy was reported in 4 studies with a total of 60 patients with 78.3% of patients pain-free during long-term follow-up. However, motor and sensory deficits occurred in 75% to 100%. DRG pulsed radiofrequency lesioning was reported by 2 studies (69 patients) with mean VAS before and after was 6.9 and 2.7, respectively. Peripheral nerve simulation was reported by 3 studies comprising 10 patients in total. This strategy was among the safest and most effective, demonstrating a VAS pain reduction from 8.6 to 2 without any complications. CONCLUSION Neurosurgical approaches for recalcitrant PHN include neuromodulatory and ablative procedures. Patients with resistant PHN should undergo minimally invasive procedures first, including SCS, PNS, or DRG radiofrequency lesioning. More invasive procedures should be reserved for refractory cases. Comparative studies are needed in order to construct a PHN neurosurgical management algorithm.