PARESTHESIA-FREE SPINAL CORD STIMULATION OF THE S1 SPINAL NERVE ROOT FOR REFRACTORY SURAL NEURALGIA: A CASE REPORT

Abstract

A 63-year-old man with a remote history of left ankle surgeries following traumatic injury, with resultant neuropathic pain secondary to sural nerve injury, was treated successfully with a left L5 DRG stimulator. He re-presents several years after a right Achilles tendon repair with resulting severe right posterolateral ankle pain. Based on the distribution of pain, a right sural nerve block was performed with > 75% relief of pain for 2 months. Cryoablations of the right sural nerve provided him with excellent pain relief for 5 months’ duration. For unclear reasons, the degree and duration of relief decreased with successive cryoablations. We then transitioned to right radiofrequency lesioning (pulsed RFL) L5 and S1 DRG with 90% relief of pain. During sensory stimulation, it was noted that the L5 DRG was discordant with his pain at the time of lesioning. For several years, the patient received serial S1 DRG RFLs, each with near complete relief lasting 4 to 8 months. Over this time period, the patient developed burning at the site of his implantable pulse generator (IPG) when the device was in the “on” mode only. The impression was that there was an electrical leak at the site where the lead inserts into the IPG. The decision was made to replace the existing IPG and add a lead over the S1 nerve root on the right, as close as possible to the DRG.