Electrically evoked compound action potentials recorded from the sheep spinal cord

Area of Science:

• Neuroscience
• Biomedical Engineering
• Pain Management

Background:

• Spinal cord stimulation (SCS) is a key therapy for chronic pain.
• Understanding the electrical response of dorsal column axons is crucial for optimizing SCS efficacy.
• Current SCS mechanisms require further elucidation for improved therapeutic outcomes.

Purpose of the Study:

• To characterize the electrical response of dorsal column axons to depolarizing stimuli during SCS.
• To investigate the influence of electrode location on these responses.
• To inform the optimization of SCS devices for pain relief and power consumption.

Main Methods:

• Recording electrically evoked compound action potentials (ECAPs) in anesthetized sheep during SCS.
• Utilizing epidural SCS leads with integrated stimulating and recording electrodes.
• Employing a novel system to minimize artifact contamination in ECAP recordings.

Main Results:

• ECAPs exhibited a triphasic morphology (P1, N1, P2 peaks).
• ECAP amplitude varied along the spinal cord, with minimums over intervertebral discs and maximums in midvertebral positions.
• Regions with depressed ECAP amplitude showed higher stimulation thresholds, impacting power consumption.

Conclusions:

• Sheep Aβ fiber potentials during SCS are location-dependent.
• Optimizing electrode placement can enhance Aβ fiber recruitment and reduce power consumption in SCS devices.
• Findings suggest potential translation to human SCS therapy optimization.