Clinical Predictors of Pain Relief with 60-Day Peripheral Nerve Stimulation: A Multicenter Observational Study.

BACKGROUND

Clinical predictors of pain relief with 60-day peripheral nerve stimulation (PNS) remained undefined. Identifying the factors associated with treatment outcomes may improve patient selection and optimize results.

OBJECTIVE

This study examined baseline physical activity, pain, disability, and psychological factors influencing early versus delayed response and non-response to a 60-day PNS.

METHODS

A prospective, multicenter, observational cohort study was conducted on 73 patients who consecutively received a 60-day PNS. Baseline assessments included pain (numeric rating scale [NRS]), disability (Oswestry Disability Index [ODI]), psychological profiles (Pain Self-Efficacy Questionnaire, PSEQ; Pain Catastrophizing Scale, PCS), and physical activity (physical activity vital signs [PAVS]). Logistic regression and principal component analysis were used to identify the predictors of response phenotypes.

RESULTS

Early (≥50% pain relief within 7-14 days of PNS implant that is sustained through the entire 60-day period) and delayed (<50% pain relief in the first 14 days but eventually reaching ≥50% before the end of the 60 days) responder rates were 26% and 43%, respectively. Non-responders (<50% pain relief at the end of the 60-day treatment period) comprised 30.1% of the group. Predictors of early response included high physical activity (OR=4.22, p=0.0006, Area Under the Curve [AUC] =0.81), high pain self-efficacy (OR=1.12, p=0.0004, AUC=0.86), and low catastrophizing (OR=0.88, p=0.0003, AUC=0.86). A delayed response was associated with a longer chronic pain duration (OR=0.83, p=0.027) and high baseline ODI (OR=0.43, p=0.002; AUC=0.79). Nonresponse was linked to psychological distress (eigenvalue =3.23, 40.3% variance), opioid dependency, and morbid obesity (eigenvalue =1.63, 20.4% variance).

CONCLUSION

This real-world study showed that baseline physical activity, psychological resilience, and pain behaviors predicted response to a 60-day PNS. Non-responders presented with psychological distress, morbid obesity, and opioid dependence. These findings may refine patient selection and help to set treatment expectations for 60-day PNS.