Identifying the Impact of Centralized Pain on Pain Outcomes after Spinal Cord Stimulator Trials (POST)

Chronic pain affects over 100 million people in the United States. Central sensitization contributes to many chronic pain syndromes and may reduce the effectiveness of peripherally directed interventions. Although spinal cord stimulation (SCS) is effective for many patients, identifying those less likely to benefit could improve patient selection and reduce unnecessary procedures. We hypothesized that centralized pain features are associated with failure to achieve meaningful analgesia during an SCS trial.

Participants completed validated questionnaires before SCS trial implantation and within 48 hours of trial removal. Measures included the Brief Pain Inventory (BPI), Central Sensitization Inventory (CSI), 2016 Fibromyalgia Diagnostic Criteria Survey, PROMIS-29 v2.0, PainDETECT, Perceived Stress Scale, PANAS, Childhood Traumatic Events Scale, CSQ-CAT, and Patient Global Impression of Change (PGIC).

67 patients were enrolled; 51 completed follow-up. Mean age was 63.5 years, with 67.2% female participants. Baseline average and worst BPI pain severity scores were 6.4 and 8.6, respectively, and mean fibromyalgianess score was 12.5. Following SCS, average and worst pain severity scores improved significantly (p < 0.001), as did all PROMIS domains (p < 0.001-0.002). Responders (≥50% reduction in worst pain) did not differ demographically from non-responders but had significantly lower fibromyalgianess (p = 0.03), CSI scores (p = 0.02), and presence of widespread pain (p = 0.03).

Patients with greater centralized pain features experienced less analgesic benefit despite overall improvements in pain and function, supporting our hypothesis that nociplastic pain burden influences SCS response. These findings suggest that pre-procedural pain phenotyping may improve patient selection.