Neuromodulation: Technology at the Neural Interface Received: March 24, 2019 Revised: June 20, 2019 Accepted: July 17, 2019 (onlinelibrary.wiley.com) DOI: 10.1111/ner.13044 Association Between Pain Scores and Successful Spinal Cord Stimulator Implantation Vwaire Orhurhu, MD, MPH* ; Robert Chu, BA † ; Mariam Salisu Orhurhu, MD, MPH ‡ ; Charles A. Odonkor, MD § Introduction: Determining reduction in pain score during spinal cord stimulation (SCS) trial is important prior to permanent SCS implantation. However, this association remains elusive. We investigate the association between post-SCS pain scores and successful permanent SCS implants. Materials and Methods: This IRB-approved, retrospective study identified patients who underwent SCS trials and implanta- tion. Predictive modeling with nonparametric regression and margins plot analysis was used to determine the threshold for post-SCS trial pain scores associated with successful permanent SCS implant (defined as >50% pain relief). Nonparametric sen- sitivity and specificity analysis was performed. p < 0.05 was considered significant. Results: Eighty-eight patients with SCS trials were retrospectively identified (57.95% female, median age 52.5 Æ 15.5 years). Of the total cohort, 79% had successful permanent SCS implantation. Post-SCS trial pain scores less than or equal to 4.9 had greater than 50% probability of a successful permanent SCS implant (97.14% sensitivity, 44.44% specificity, ROC = 0.71). Post- SCS trial pain scores between 4 and 7 were associated with a significantly higher probability of a successful SCS implant among patients without spine surgery compared with those with a history of spine surgery. Compared with males, females with pain scores between 5 and 7 had a higher probability of a successful SCS implant. Conclusion: Low pain scores after SCS trial are predictive of successful SCS implants with high sensitivity. Males and surgical patients with higher pain scores had a lower probability of successful SCS implant than their counterparts. Larger studies are needed to further elucidate this relationship. Keywords: Gender and spinal cord stimulator, pain scores, prediction, spinal cord stimulation, spinal cord stimulation trial Conflict of Interest: Dr. Charles Odonkor and Dr. Vwaire Orhurhu designed the study. Dr. Vwaire Orhurhu performed the sta- tistical analysis. Dr. Vwaire Orhurhu, Robert Chu, Dr. Mariam Salisu Orhurhu and Dr.Charles Odonkor were involved in drafting the manuscript. All authors critically revised the manuscript, interpreted the results, and performed a critical review of the manuscript for intellectual content. INTRODUCTION Permanent spinal cord stimulation (SCS) implant remains one of the standard interventions used to provide pain relief for chronic pain patients with failed back surgery syndrome (FBSS), complex regional pain syndrome (CRPS), and peripheral vascular disease (PVD) (1–4). The mechanism of action is postulated to inhibit the neural activity of nociception-transmitting fibers in the dorsal horn of the spinal cord and GABA-responsive wide-dynamic-range neu- rons (5–7). Several clinical studies have shown that approximately 60% of patients report pain reduction after implantation of SCS, and the procedure has been shown to be overall cost-effective (8–11). Several studies have attempted to determine predictors of pain reduction following SCS implantation. Patient demographic fac- tors associated with better SCS outcomes include lower age, lack of psychologic comorbidity, and lower BMI (12–15). Implantation- related factors that have been shown to increase efficacy include a shorter interval between onset of symptoms to implantation, decreased complication rates, increasing area covered by the SCS leads, increasing number of leads, and pain relief at one and six months following permanent SCS implantation (16–19). A study by Hord et al. also found associations between successful sympathetic block and better pain control in both SCS trials and permanent SCS implantation (20). However, it remains unclear to what extent pain reduction dur- ing the trial period is associated with long-term success of the permanent implant. Several studies have shown that around 25% of patients fail their trial period and do not go on to have perma- nent implantation, with the use of paddle electrodes, presence 1 Address correspondence to: Charles A. Odonkor, MD, Harvard Medical School, Massachusetts General Hospital, 55 Fruit Street, White 437, Boston MA 02114, USA. Email: charles.odonkor@mgh.harvard.edu * Department of Anesthesia, Critical Care, and Pain Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA; † Johns Hopkins University School of Medicine, Baltimore, MD, USA; ‡ Department of Anesthesia, Critical Care and Pain Medicine, Johns Hopkins Hospital, Baltimore, MD, USA; and § Department of Anesthesia, Critical Care and Pain Medicine, Division of Pain, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA For more information on author guidelines, an explanation of our peer review process, and conflict of interest informed consent policies, please go to www. wiley.com/WileyCDA/Section/id-301854.html Source(s) of financial support: The authors have no sources of financial support to disclose. Neuromodulation 2019; ••: ••–•• © 2019 International Neuromodulation Society www.neuromodulationjournal.com