Combined Spinal Cord and Peripheral Nerve Field Stimulation for Persistent Post-Herniorrhaphy Pain

Abstract

Chronic post-hernia pain is a common complication after inguinal herniorrhaphies. Peripheral nerve field stimulation (PNFS) and spinal cord stimulation (SCS) are two new promising treatment modalities. Four patients with persistent neuropathic post-hernia pain were recruited for this prospective study. Electrodes were inserted into the epidural space of the spinal canal and into the subcutaneous tissue in the inguinal region during a single surgical procedure. During a 14-day trial, double-blind stimulation was performed via an external stimulator: three days using the spinal electrode (SCS), three days using the inguinal electrode (PNFS), three days using both (SCS + PNFS), and five days off, with an alternating order from patient to patient. During the trial, pain intensity was assessed thrice daily by the visual analog scale. Additionally, pain intensity and quality of life (QOL) were assessed before and after surgical intervention by the Brief Pain Inventory, SF36 scale, and Pain Disability Index. All patients had a marked pain reduction during the trial phase, and this reduction was more prominent when both electrodes were activated simultaneously (p < 0.001). At the late follow-up, a significant pain reduction and improvement of QOL was observed in three patients. Both SCS and PNFS are effective in treating post-hernia pain, but the magnitude of pain reduction was more prominent with concomitant stimulation. Combined PNFS and SCS should be considered for patients with a less than optimal response to either SCS or PNFS. More studies are necessary to address the cost-effect issues of this new approach to treatment.