24-month Real-World Study of Spinal Cord Stimulation in Failed Back Surgery Patients with Refractory Pain

Abstract

BACKGROUND: Failed Back Surgery Syndrome (FBSS) causes disability and lowers health-related quality of life (HRQoL) for patients. Many patients become refractory to Conventional Medical Management (CMM) and Spinal Cord Stimulation (SCS) is advised. However, comparative effectiveness research of both clinical approaches still lacks further evidence. OBJECTIVES: This study describes Comparative Effectiveness Research of CMM versus SCS to provide real world evidence regarding the appropriate means for FBSS management, in terms of Patient-Reported Outcomes Measures. STUDY DESIGN: Naturalistic, pragmatic, prospective observational multicenter SEFUDOCE-study SETTING: FBSS patients attending clinical programmed visits in Pain Unit at Hospital Universitario de La Princesa and at Hospital General Universitario de Alicante (Spain). METHODS: Study evaluates the impact on pain, functional limitation, and HRQoL of CMM versus SCS in the management of FBSS. Patients completed Pain Detect Questionnaire, Oswestry Disability Index, EQ-5D-3L, Medical Outcomes Study Sleep Scale, and Hospital Anxiety and Depression Scale at baseline and at 3, 6, 12, 18 and 24 months. Longitudinal data were analysed with repeated-measures one-way analysis of variance adjusting by confounders. RESULTS: Eighty-five adults patients with FBSS receiving treatment according to current clinical practice were assessed. After 24 months, the PainDETECT Questionnnaire showed that CMM patients maintained similar scores, while SCS patients reduced their overall score (current pain: 6 CMM versus 4.21 SCS, P = 0.0091; intensity strongest pain: 7.77 CMM versus 6.07 SCS, P = 0.0103; average pain: 6.46 CMM versus 4.75 SCS, P = 0.0012). For the Oswestry Disability Index, the Medical Outcomes Study Sleep Scale, and the Hospital Anxiety and Depression Scale no significant inter-group differences were found. EQ-5D utility improved in SCS patients from baseline (baseline: 0.32 CMM versus 0.22 SCS; 24-month: 0.37 CMM versus 0.63 SCS, P = 0.026). Twenty-four month follow-up showed unlikely presence of neuropathic pain and moderate disability in SCS patients, whereas the CMM patients maintained baseline health state. LIMITATIONS: Given the nature of the intervention, conducting a blinded study was not considered practically feasible. A larger sample could also overcome having younger patients in the SCS arm. CONCLUSIONS: SCS may improve the HRQoL and functionality of FBSS patients with refractory pain in the long-term compared to CMM alone. KEY WORDS: Chronic pain management, conventional medical management, failed back surgery syndrome, observational study, spinal cord stimulation