title: Acute vs. Prolonged Screening for Spinal Cord Stimulation in Chronic Pain.
abstract: Spinal cord stimulation (SCS) was performed to test the hypothesis that pain relief data during acute (15 minute intraoperative) and prolonged (5 day) SCS screening have equivalent predictive value for long-term successful SCS control of chronic low back pain and/or lower extremity pain. A retrospective series of patients with chronic low back and/or lower extremity pain underwent either percutaneous or open (ie, laminectomy) SCS implantation during which acute intraoperative followed by prolonged screening trials for percentage pain relief (%PR) were performed. Data were analyzed for (a) correlation between positive predictive value (PPV) of acute and prolonged SCS screening for %PR and (b) PPV of acute vs. prolonged screening %PR for long-term SCS %PR. Fifty-four patients (male/female = 38/16; mean age ± SEM = 54.2 ± 2.0 years) underwent thoracic (T) (mean level = T9.1 ± 0.4) percutaneous (n = 33) and laminectomy (n = 21) implantation of SCS for acute (15 minute intraoperative) and prolonged (5.0 ± 0.3 days) SCS screening of pain relief. Correlation between successful (> 50%PR) pain relief during acute (n = 53/54, PPV = 98%) and prolonged (n = 47/52, PPV = 90%) screening was significant (Spearman Rank Correlation Coefficient, SRCC = 0.462, p < 0.01). After permanent SCS implantation, at mean follow-up = 9.4 ± 1.5 months, acute and prolonged SCS screening %PR PPV's were each statistically significant for predicting long-term SCS relief of chronic pain (n = 31/38, PPV = 82% and n = 31/36, PPV = 86%, SRCC = 0.462 and 0.433, respectively, p < 0.01).  We conclude that successful pain relief during acute SCS screening is highly correlated with successful prolonged SCS screening of chronic low back and/or lower extremity pain relief. Acute and prolonged SCS screening appear to have equivalent predictive value for successful long-term SCS control of chronic low back and/or lower extremity pain. These preliminary results suggest potential justification for eliminating prolonged and retaining acute (intraoperative) SCS screening for selection of permanent SCS implantation candidates.
authors.affiliation: Division of Neurosurgery, Department of Surgery, and                                      Department of Anesthesiology, University of Arizona College of Medicine, Tucson, Arizona.
authors.forename: Martin E
authors.initials: ME
authors.lastname: Weinand
authors.forename: Hassan
authors.initials: H
authors.lastname: Madhusudan
authors.forename: Bennett
authors.initials: B
authors.lastname: Davis
authors.forename: Miguel
authors.initials: M
authors.lastname: Melgar