Can Peripheral Nerve Stimulation Reduce Neuropathic Pain in Patients with Brachial Plexus Injuries?

Introduction: Up to 95% of patients with brachial plexus injuries (BPIs) develop neuropathic pain. Peripheral nerve stimulation (PNS) shows promise as a targeted treatment for neuropathic pain, however, it has been relatively unexplored in large, prospective studies. This study aims to summarize existing literature on PNS for treating neuropathic pain in adults with BPI and assess its efficacy in pain reduction.

Methods: A systematic literature search was conducted. Articles examining PNS for neuropathic pain secondary to BPI were included. Pain reduction, measured as a change in Numerical Rating Scale (NRS) score, was compared between pre-stimulation and post-stimulation cohorts. Regression analysis was conducted to evaluate the effects of injury etiology and stimulation technique on pain reduction. Results are presented as mean NRS scores with β coefficients and 95% CIs.

Results: After reviewing 314 articles, 8 studies met inclusion criteria, encompassing 15 patients undergoing PNS for BPI. The cohort was entirely male with a mean age of 45.3 years. Aggregate analysis revealed NRS scores were significantly lower following PNS (7.79) compared to before PNS (2.51) (p < 0.001). Injuries from tumors were associated with greater pain reduction (8.50 pre-PNS, 1.50 post-PNS) (β = 1.83, 95% CI: [-0.97, 4.64]) than traumatic injuries (7.81 pre-PNS, 3.14 post-PNS) (β = -0.83, 95% CI: [-2.92, 1.25]), although these effects were statistically non-significant. Percutaneous PNS (8.3 pre-PNS, 1.5 post-NRS) was associated with greater pain reduction compared to open techniques (5.25 pre-PNS, 2.08 post-PNS) (β = -1.99, 95% CI: [-0.77, 4.77]), though not statistically significant.

Conclusion : Pooled analysis of BPI patients undergoing PNS for neuropathic pain reveals pain reduction after PNS. Future research with larger cohorts will be integral in elucidating the effects of injury etiology and stimulation parameters on pain reduction. Nevertheless, in patients with severe neuropathic pain from BPI, multimodal pain control including PNS may significantly improve recovery.