Use of a Psychological Evaluation Tool as a Predictor of Spinal Cord Stimulation Outcomes.

Introduction: Preoperative work-up for spinal cord stimulation (SCS) includes a psychological assessment; however, no one psychological factor has correlated with poor outcomes across studies. We developed a Psychological Evaluation Tool for Spinal Cord Stimulation Candidacy (PETSCSC), which includes all factors in the literature found to correlate with outcomes. In this study, we examine whether PETSCSC correlates with postoperative outcomes.

Methods: Patients undergoing SCS were prospectively enrolled in this study. PETSCSC scores were obtained preoperatively. Numeric rating scale (NRS), global impression of change (GIC), pain catastrophizing scale (PCS), McGill pain questionnaire (MPQ), Oswestry disability index (ODI), and Beck Depression Inventory were assessed preoperatively and postoperatively. Outcomes were correlated with PETSCSC scores.

Results: Thirty-four SCS patients had a mean follow-up of 9.88 ± 2.91 months. At latest follow-up, we observed significant improvement in NRS, PCS, MPQ, and ODI. Total PETSCSC score exhibited significant correlation with GIC (p = 0.026, r = 0.380) and improvement in PCS total (p = 0.041, r = 0.351), and MPQ affective (p = 0.002, r = 0.517) scores. The PETSCSC emotive subset significantly correlated with GIC (p = 0.020, r = 0.395). The PETSCSC depression subset significantly correlated with improvement in PCS rumination (p = 0.009, r = 0.439), PCS helplessness (p = 0.021, r = 0.393), PCS total (p = 0.021, r = 0.394), and MPQ affective (p = 0.002, r = 0.501). The PETSCSC therapy subset significantly correlated with improvement in MPQ sensory (p = 0.026, r = -0.381) and MPQ affective (p < 0.001, r = 0.583).

Discussion: PETSCSC scores and subscores demonstrate significant correlation with pain outcomes used in assessment of SCS efficacy. Higher PETSCSC scores correlate with greater improvement in GIC, MPQ affective, and PCS scores. Stratification of these patients based on PETSCSC total and subset scores could help with prognostication.