Effect of Restorative Neurostimulation on Major Drivers of Chronic Low Back Pain Economic Impact

Introduction:
Chronic low back pain (CLBP) has significant economic and social consequences. Pain impact is an important construct that correlates with both functional and economic outcomes. High impact pain has been defined by the US Department of Health and Human Services (HHS) as pain that has been present on most days for six months or more that “is associated with substantial restriction of participation in work, social, and self-care activities”. When applied to specifically CLBP, high impact pain patients are more likely to be frequent users of high-cost healthcare resources, reporting substantially higher average pain intensity, and describing higher pain-related interference with life and work-related activities.

Therapies that deliver durable benefit in both pain and dysfunction reduce downstream direct and indirect healthcare costs. Restorative neurostimulation is a therapy that is applied to CLPB patients that have failed conservative management and have few viable therapeutic options remaining.

Aims/

Objectives:
Investigate the long-term clinical benefit of restorative neurostimulation and it impact on work-related abilities.

Methods:
A cohort of 146 patients with complete data were included in this analysis from the patients completing 2 year follow-up enrolled at 26 international multidisciplinary centers as part of a randomized controlled IDE trial to evaluate the safety and efficacy of the restorative neurostimulation in patients with refractory mechanical CLBP and confirmed multifidus muscle dysfunction.

Direct drivers were obtained from by stratifying patients into three categories to analyse the effect that pain impact had on clinical outcomes. Using the definition proposed by the HHS, we stratified patients to high, medium, and low impact CLBP. Pain duration was considered as at least 6 months of chronic pain and pain severity was VAS > 4. Indirect drivers were collected through questionnaires evaluating work impact. Work performance was assessed as “ability to do your work at its best” on a 10-point numerical rating scale. A descriptive statistical analysis was performed.

Results:
Following two years of therapy 124 (84.9%) of all patients were in the low impact pain class. Of the 103 patients with high impact pain at baseline, 85 (82.5%) reported low impact pain, 5 (4.8%) transitioned to a moderate pain class and 13 (12.6%) remained unchanged.
At baseline, 9/146 (6.2%) of patients reported no work problems due to CLBP. This improved to 67/146 (45.9%) and further to 50.1% after 1 and 2 years of therapy respectively. Mean score at baseline 6.0±0.2 improved to 7.8±0.2, 8.1±0.2 and 8.3±0.2 at 6 months, 1 and 2 years, respectively. The proportion of patients rating their work ability as a 9 or10 was 87/146 (60%) at 2 years compared to 21/146 (14%) at baseline.

Conclusions:
The established literature suggests that there is a disproportionate distribution of healthcare resource utilization between mildly and highly impacted patients. Restorative neurostimulation is one therapeutic option that should reduce healthcare consumption over the long term in line with meaningful and durable symptom relief and transition from the high impact pain category.