Short-term patient reported outcomes of multi-contact independent current control spinal cord stimulation in patients with chronic low back and extremity pain: an exploratory prospective cohort study.

Introduction: The effect of multi-contact independent current control (MICC) spinal cord stimulation (SCS) on patient-reported outcomes in those who have lost therapeutic efficacy of a conventional SCS is not well described. We prospectively evaluated self-reported pain, disability, and quality of life in patients with persistent spinal pain syndrome type 2 (PSPS-2) who were converted from a conventional to MICC SCS.

Methods: Patients with PSPS-2 who had lost therapeutic efficacy with a constant current control (CCC) or voltage control (VC) system were enrolled, and had a MICC generator implanted. All participants were followed prospectively with standardized assessments of pain (Visual Analog Scale, VAS), condition-specific function (Oswestry Disability Index, ODI), and quality of life (Short-Form-36) at three- and six-months post-implantation.

Results: Fifteen participants were eligible for inclusion; three were lost to follow-up. Mean VAS score was significantly decreased at 3 months (5.3±2.5, p=0.009) and 6 months (5.1±2.8, p=0.005) relative to pre-implantation (VAS 8.3±0.8). At 30 months, mean VAS remained significantly decreased (5.8±1.6, p<0.001). Mean disability score was significantly decreased at six months (ODI 40.5±14.7, p=0.029) compared to the mean preoperative score (53.6±14.7). At 6 months, the minimum clinically important difference (MCID) for VAS was met by 90% of patients and for ODI by 100%.

Conclusion: This exploratory study suggests that MICC programming may represent a reasonable short-term salvage option for patients with PSPS-2 who have lost therapeutic efficacy with a CCC or VC SCS system. A larger study is required to evaluate superiority in terms of long-term pain control of MICC versus conventional SCS.