Treatment of Chronic, Intractable Pain With a Conventional Implantable Pulse Generator

Abstract

To provide further short-term (6 mo) and long-term (1 y) evidence for the use of spinal cord stimulation (SCS) with a conventional implantable pulse generator in the management of chronic, intractable pain. We conducted a meta-analysis of 4 prospective, multicenter studies that collected outcome data from patients implanted with SCS to treat chronic pain of the trunk and/or limbs (Genesis IPG system). Two of these were conducted as long-term studies lasting 1 year, and 2 as shorter term studies lasting 6 months. A total of 300 patients from 28 investigational sites were prospectively evaluated for efficacy at 3 months after implant and safety at 6 months after implant. None of the sites participated in more than one study. Outcome measures included patient-reported percent of pain relief, patient satisfaction, quality of life improvement, pain evaluation (0 to 10 rating), pain relief rating, Short-Form McGill Pain Questionnaire, visual analog scale, the Short Form-36, and the total number of adverse events (AEs). At 3 months after implantation of the permanent system, 75.4% of the patients (190/252) reported a 50% or greater pain relief as determined by the patient-reported degree of pain relief. Similarly, assessment of patient satisfaction with SCS therapy showed that 86.1% of patients (217/252) in all 4 studies were satisfied or very satisfied with the therapy at 3 months. In the 2 long-term studies, 80.9% of patients (140/173) were satisfied or very satisfied with the therapy at the 1-year evaluation point. Quality-of-life (QoL) data indicated that at 3 months after implant, 77.8% of patients (196/252) reported QoL as improved or greatly improved. Similarly, QoL was improved or greatly improved for 74.0% patients in the long-term study at 1 year (128/173). In the safety analysis, AEs were reviewed for all 4 studies. A total of 190 AEs were reported in 117 of 300 patients during all studies. This analysis provides further evidence of the safety and effectiveness of SCS in treating chronic intractable pain of the trunk and/or limbs. Specifically, it underscores a high level of effectiveness and acceptable safety concerns in the use of nonrechargeable SCS devices.