Short Therapy, Long Relief: Predictors of 12 Month Outcomes After 60 Day Peripheral Nerve Stimulation

Introduction: Sixty day peripheral nerve stimulation (PNS) is a temporary neuromodulation modality for chronic pain. 1-3 Prior studies link higher physical activity, greater pain self efficacy and lower catastrophizing with favorable responses during the 60 day treatment period but it is unclear whether these baseline characteristics or early response predict sustained relief. 4,5

Objective: To identify baseline predictors of achieving ≥50 % pain relief at 12 months after a 60 day PNS program and to assess whether end of treatment response predicts 12 month outcomes.

Methods: This prospective multicenter cohort study enrolled 110 participants. The primary endpoint was the proportion of patients achieving at least 50 % pain relief at 12 months after completing the 60 day PNS. Baseline measures included pain self efficacy (PSEQ ≥ 40), pain catastrophizing (PCS ≥ 30), pain related disability (Oswestry Disability Index [ODI]), pain duration and physical activity (PAVS; ordinal 1–3). We recorded the proportion achieving ≥ 50 % pain relief at 60 days and at 12 months. Logistic regression estimated odds ratios (ORs) for baseline predictors and for the prognostic value of 60 day response.

Results: At 12 months, 91 of 110 participants (82.7 %) achieved ≥ 50 % pain relief. Responders at 60 days were markedly more likely to maintain relief at one year (OR ≈ 11.1, 95 % CI 3.34–36.81). Higher baseline self efficacy increased the odds of a 12 month response (OR ≈ 6.67, 95 % CI 1.45–30.56), whereas higher catastrophizing (OR ≈ 0.10, 95 % CI 0.03–0.38) and greater disability (OR≈ 0.26, 95 % CI 0.09–0.70), reduced the odds of sustained relief. Greater physical activity was associated with improved outcomes (OR≈ 7.70, 95 % CI 2.68–22.16). Adjusting for disability, the association between 60 day response and 12 month outcomes persisted (OR 9.19, 95 % CI 2.69–31.40, p = 0.0004). In a model including both disability and physical activity, the effect of 60-day response attenuated (OR1.91, 95 % CI 0.30–12.10, p = 0.494), whereas physical activity remained a significant predictor (OR 4.55, 95 % CI 1.03–20.17, p = 0.046).

Conclusion: In this cohort, most patients experienced durable pain relief 12 months after completing a 60-day PNS program. Early response predicted longterm success, but was impacted by baseline physical activity and disability. The findings corroborate prior reports and suggest that evaluating psychosocial factors alongside early response could inform patient selection. 4,5 Future research should validate these predictors in a larger and more diverse cohort.