First evidence of a biomarker-based dose-response relationship in chronic pain using physiological closed-loop spinal cord stimulation.

BACKGROUND AND OBJECTIVES: In spinal cord stimulation (SCS) therapy, electricity is the medication delivered to the spinal cord for pain relief. In contrast to conventional medication where dose is determined by desired therapeutic plasma concentration, there is lack of equivalent means of determining dose delivery in SCS. In open-loop (OL) SCS, due to the dynamic nature of the epidural space, the activating electric field delivered is inconsistent at the level of the dorsal columns. Recent Food and Drug Administration guidance suggests accurate and consistent therapy delivered using physiologic closed-loop control (PCLC) devices can minimize underdosage or overdosage and enhance medical care. PCLC-based evoked compound action potential (ECAP)-controlled technology provides the ability to prescribe a precise stimulation dose unique to each patient, continuously measure neural activation, and objectively inform SCS therapy optimization.

METHODS: Neurophysiological indicator metrics of therapy dose, usage above neural activation threshold, and accuracy of SCS therapy were assessed for relationship with pain reduction in over 600 SCS patients.

RESULTS: Significant relationships between objective metrics and pain relief across the patient population are shown, including first evidence for a dose-response relationship in SCS.

CONCLUSIONS: Higher dose, more time over ECAP threshold, and higher accuracy are associated with better outcomes across patients. There is potential to optimize individual patient outcomes based on unique objective measurable electrophysiological inputs.