1. 2017;20;95-106Successful Long-term Nerve Root Stimulation for Chronic Neuropathic Pain: A Real World, Single Center Canadian Experience
   Prospective Study
   Adrian B. Levine, BSc, David A. Steven, MD, Andrew G. Parrent, MD, FRCSC, and Keith W. MacDougall, MD, FRCSC.

BACKGROUND: Spinal cord stimulation (SCS) is a well-established treatment for chronic neuropathic pain in the lower limbs. However, some patients have pain in distributions that are difficult to target specifically and consistently with SCS. This often involves pain in the groin or upper limbs, or pain limited to a specific dermatome. We hypothesized that dorsal nerve root stimulation (DNRS) would provide similar pain relief for these patients, compared to our results using SCS.

OBJECTIVES: In this study we report our experience treating patients with chronic neuropathic pain using SCS and DNRS.

STUDY DESIGN: Open label, prospective study that includes all patients treated with a new trial stimulator system at a single center between July 1, 2011, and October 31, 2013.

SETTING: Academic university neurosurgical pain center.

METHODS: One hundred thirty-two consecutive patients had trials of spinal stimulation. Seventy-six patients went on to permanent implants, of which 26 received only DNRS, 47 only SCS, and 3 both. The technique was selected based on clinical assessment and intraoperative test stimulation. Other than pain location and diagnosis, the DNRS and SCS groups had similar baseline characteristics. Follow-up is reported at 12 months. Patients were assessed using a visual analogue scale (VAS) for pain, the SF-36 for quality of life, and the morphine equivalent daily dose (MEDD).

RESULTS: At 12 months, the average VAS score for the DNRS group had decreased from 7.5 (SD 1.4) to 4.4 (SD 2.6) and 47% of patients with permanent implants achieved > 50% pain reduction. There were improvements in all subscores and component summary scores of the SF-36. The MEDD had been reduced in 55% of the patients with available data. There was no significant difference in complication or revision rates between the 2 groups.

LIMITATIONS: Patients were not randomized to treatment groups, and instead were assigned to SCS or DNRS based on what was expected to provide superior pain coverage. There is incomplete follow-up data for some patients due to missed clinic visits.

CONCLUSIONS: In our study, DNRS provided excellent pain reduction, quality of life improvement, and opioid medication use decreases. We conclude that it is an effective long-term treatment for chronic neuropathic pain.

Key words: Spinal cord stimulation, dorsal nerve root stimulation, lumbar, thoracic, cervical, neuropathic pain, neuromodulation, clinical effectiveness, chronic pain, visual analogue scale