Peripheral Nerve Stimulation for Chronic Neuropathic Pain: A Health Technology Assessment.

Abstract

Background: Chronic neuropathic pain is a major health problem that adversely affects people's physical and mental well-being, as well as their quality of life. Percutaneous peripheral nerve stimulation (PNS) may offer a minimally invasive option earlier in the treatment continuum for adults with chronic neuropathic pain that is refractory to conventional medical management. We conducted a health technology assessment of PNS for adults with chronic neuropathic pain, which included an evaluation of effectiveness, safety, cost-effectiveness, the budget impact of publicly funding PNS, and patient preferences and values.

Methods: We performed a systematic literature search of the clinical evidence. We assessed the risk of bias of each included study using the Cochrane risk-of-bias tool for randomized controlled trials and the Risk of Bias in Non-randomized Studies - of Interventions for observational studies, and the quality of the body of evidence according to the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) Working Group criteria. We performed a systematic economic literature search and conducted a cost-utility analysis with a 3-year horizon from a public payer perspective. We also analyzed the budget impact of publicly funding PNS in adults with chronic neuropathic pain in Ontario. To contextualize the potential value of PNS, we spoke to people with chronic pain, and to care partners of patients with chronic pain.

Results: We included 17 publications (2 randomized controlled trials and 12 nonrandomized studies) in the clinical evidence review. These studies included chronic neuropathic pain in the trunk and the upper and lower extremities. Compared with placebo controls in adults with chronic neuropathic pain that is refractory to conventional medical management, permanent PNS likely decreases pain scores, likely improves functional outcomes, and likely improves health-related quality of life, but it has little to no effect on the use of pain medications (all GRADEs: Moderate). Compared with before implantation in adults with chronic neuropathic pain, permanent PNS may decrease pain scores, may decrease the use of pain medications, may improve functional outcomes, and may improve health-related quality of life (all GRADEs: Low). Compared with placebo controls in adults with chronic postamputation pain, temporary PNS may decrease pain scores, may decrease use of pain medications, may improve functional outcomes, and may improve health-related quality of life (all GRADEs: Low). Compared with before implantation in adults with chronic postamputation pain, temporary PNS may decrease pain scores, may decrease the use of pain medications, may improve functional outcomes, and may improve health-related quality of life (all GRADEs: Low). We did not find any studies that compared permanent PNS to temporary PNS. Implantation of a PNS system is a reasonably safe procedure; most adverse events were localized and mild in intensity (GRADEs: Moderate to Low).The incremental cost-effectiveness ratio of PNS in addition to standard care compared with standard care alone is $87,211 per quality-adjusted life-year (QALY) gained. The probability of PNS in addition to standard care being cost-effective versus standard care alone is 1.02% at a willingness-to-pay of $50,000 per QALY gained and 64.88% at a willingness-to-pay of $100,000 per QALY gained. The annual budget impact of publicly funding PNS in Ontario over the next 5 years ranges from an additional $0.97 million in year 1, increasing to $3.15 million in year 5, for a total of $10.09 million over 5 years. People with chronic pain and their family members and care partners viewed PNS favourably. Those who had direct experience with permanent PNS perceived it to be effective in reducing their pain levels, leading to a positive impact on their quality of life and mental health. Current barriers to accessing PNS include lack of awareness, cost, and geography.

Conclusions: In adults with chronic neuropathic pain that is refractory to conventional medical management, permanent PNS likely improves pain outcomes, functional outcomes, and health-related quality of life but has little to no effect on the use of pain medications compared with placebo controls. Temporary PNS may improve pain outcomes, functional outcomes, and health-related quality of life, and it may reduce the use of pain medications. Implantation of a permanent or temporary PNS system is reasonably safe. The incremental cost-effectiveness ratio of PNS in addition to standard care compared with standard care alone is $87,211 per QALY gained. We estimate that publicly funding PNS in Ontario would result in additional costs of $10.09 million over the next 5 years. People who had direct experience with permanent PNS spoke of its effectiveness in reducing their pain levels and its positive impact on their quality of life and mental health. Barriers to accessing PNS include lack of awareness, cost, and geography.