Overview
The Evoke system by Saluda Medical is the world's first closed-loop spinal cord stimulator. While conventional SCS delivers fixed or manually-adjusted stimulation, Evoke reads the spinal cord's electrical response to each stimulus pulse — the Evoked Compound Action Potential (ECAP) — and adjusts the next pulse automatically, in real time, thousands of times per day.
This is a fundamental architectural advance over open-loop SCS. In open-loop systems, stimulation dosing doesn't account for changes in spinal cord proximity caused by posture changes, breathing, or movement — resulting in under- or over-stimulation as the patient moves. Evoke's closed-loop control maintains consistent neural activation regardless of body position.
Approved by the FDA in 2022, Evoke received the Breakthrough Device designation and is supported by one of the most rigorous evidence packages in SCS history — including the EVOKE RCT published in Nature Medicine.
Key Technology
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ECAP Sensing
System senses the evoked compound action potential — the electrical signal produced by dorsal column fibers in response to each stimulation pulse — within microseconds of delivery.
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Real-Time Closed-Loop Control
ECAP amplitude is compared to the patient's therapeutic target. Stimulation amplitude is automatically adjusted pulse-by-pulse to maintain consistent neural recruitment.
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Posture-Invariant Therapy
As the spinal cord shifts relative to the electrode with movement, ECAP feedback compensates automatically — eliminating the need for posture-based programming programs.
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Therapy Insight Data
System logs ECAP responses and stimulation adjustments continuously, providing clinicians with objective neural biomarker data to guide programming and follow-up.
Clinical Evidence
Landmark RCT
EVOKE Trial — Nature Medicine (2020)
Double-blind RCT (N=134). Closed-loop SCS achieved ≥50% pain relief in 83% of patients at 12 months vs. 61% for open-loop. Superior TIR (time in therapeutic range) — first time this metric was defined and validated for SCS.
Real-World Data
EVOKE 24-Month Follow-Up
Extended follow-up maintained outcomes at 2 years with no degradation. Responder rate remained above 80%, confirming durable benefit of closed-loop therapy vs. open-loop.
Breakthrough
FDA Breakthrough Device Designation
Designated a Breakthrough Device prior to PMA submission, reflecting the FDA's recognition that ECAP-based closed-loop control represents a meaningful advance over existing SCS technology.
Regulatory Timeline
2013
Saluda Medical founded in Sydney, Australia; ECAP sensing concept patented
2017
First-in-human implants; TGA (Australia) approval for Evoke
2020
EVOKE RCT published in Nature Medicine; FDA Breakthrough Device designation
2022
FDA PMA approval; CE Mark maintained; US commercial rollout begins
2025
Expanding US implanting center network; next-gen Evoke platform in development