Treatment of chronic, intractable pain with a conventional implantable pulse generator: A meta-analysis of 4 clinical studies

Objective: 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. MATERIALS AND Methods: 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). Results: 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. Conclusions: 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.