Spinal cord stimulation for chronic pain of neuropathic or ischaemic origin: systematic review and economic evaluation

Objectives: This report addressed the question 'What is the clinical and cost-effectiveness of spinal cord stimulation (SCS) in the management of chronic neuropathic or ischaemic pain?' Data sources: Thirteen electronic databases [including MEDLINE (1950-2007), EMBASE (1980-2007) and the Cochrane Library (1991-2007)] were searched from inception; relevant journals were hand-searched; and appropriate websites for specific conditions causing chronic neuropathic/ischaemic pain were browsed. Literature searches were conducted from August 2007 to September 2007. Review methods: A systematic review of the literature sought clinical and cost-effectiveness data for SCS in adults with chronic neuropathic or ischaemic pain with inadequate response to medical or surgical treatment other than SCS. Economic analyses were performed to model the cost-effectiveness and cost-utility of SCS in patients with neuropathic or ischaemic pain. Results: From approximately 6000 citations identified, 11 randomised controlled trials (RCTs) were included in the clinical effectiveness review: three of neuropathic pain and eight of ischaemic pain. Trials were available for the neuropathic conditions failed back surgery syndrome (FBSS) and complex regional pain syndrome (CRPS) type I, and they suggested that SCS was more effective than conventional medical management (CMM) or reoperation in reducing pain. The ischaemic pain trials had small sample sizes, meaning that most may not have been adequately powered to detect clinically meaningful differences. Trial evidence failed to demonstrate that pain relief in critical limb ischaemia (CLI) was better for SCS than for CMM; however, it suggested that SCS was effective in delaying refractory angina pain onset during exercise at short-term follow-up, although not more so than coronary artery bypass grafting (CABG) for those patients eligible for that surgery. The results for the neuropathic pain model suggested that the cost-effectiveness estimates for SCS in patients with FBSS who had inadequate responses to medical or surgical treatment were below 20,000 pound per quality-adjusted life-year (QALY) gained. In patients with CRPS who had had an inadequate response to medical treatment the incremental cost-effectiveness ratio (ICER) was 25,095 pound per QALY gained. When the SCS device costs varied from 5000 pound to 15,000 pound, the ICERs ranged from 2563 pound per QALY to 22,356 pound per QALY for FBSS when compared with CMM and from 2283 pound per QALY to 19,624 pound per QALY for FBSS compared with reoperation. For CRPS the ICERs ranged from 9374 pound per QALY to 66,646 pound per QALY If device longevity (I to 14 years) and device average price (5000 pound to 15,000) pound were varied simultaneously, ICERs were below or very close to 30,000 pound per QALY when device longevity was 3 years and below or very close to 20,000 pound per QALY when device longevity was 4 years. Sensitivity analyses were performed varying the costs of CMM, device longevity and average device cost, showing that ICERs for CRPS were higher. In the ischaemic model, it was difficult to determine whether SCS represented value for money when there was insufficient evidence to demonstrate its comparative efficacy. The threshold analysis suggested that the most favourable economic profiles for treatment with SCS were when compared to CABG in patients eligible for percutaneous coronary intervention (PCI), and in patients eligible for CABG and PCI. In these two cases, SCS dominated (it cost less and accrued more survival benefits) over CABG. Conclusions: The evidence suggested that SCS was effective in reducing the chronic neuropathic pain of FBSS and CRPS type I. For ischaemic pain, there may need to be selection criteria developed for CLI, and SCS may have clinical benefit for refractory angina short-term. Further trials of other types of neuropathic pain or subgroups of ischaemic pain, may be useful.