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Spine Rapid Fire Abstract

Spine

Improved Selectivity in Eliciting Evoked Electromyography Responses with High-Resolution Spinal Cord Stimulation

Saturday, May 4, 2024
3:41 PM – 3:43 PM CT
Location:  S403ab
Disclosure(s):
Julie G. Pilitsis, MD, PhD, MBA: Abbott: Grant/Research Support (Ongoing); Aim Medical Robotics: Advisor (Ongoing), Stock Shareholder (excluding mutual funds) (Ongoing); Boston Scientific: Grant/Research Support (Ongoing); Focused Ultrasound Foundation: Grant/Research Support (Ongoing); Medtronic: Grant/Research Support (Ongoing); NIH 2R01CA166379: Grant/Research Support (Ongoing); NIH R01EB030324: Grant/Research Support (Ongoing); NIH-NeuroBlueprint MedTech 5U54EB033650: Grant/Research Support (Ongoing)
Introduction: As spinal cord stimulation (SCS) offers a therapy for increasing numbers of patients with chronic pain and with spinal cord injury, it becomes increasingly important to better understand its somatotopy. In this prospective study (NCT05459324) we investigate whether high-resolution spinal cord stimulation (HR-SCS) offers improved selectivity assessed through elicitation of evoked electromyography (EMG) responses as compared to commercial leads.

Methods: Vertical tripole configurations were used to elicit EMG responses in both types of paddles placed for standard of care indications between T6-T10. In HR-SCS, evoked EMG responses in lower extremity/abdominal muscle groups were monitored at 6 to 8 mediolateral sites. All commercial paddle columns were tested. Percentage change in the maximum root mean square value (maxRMS) was calculated at a group level. Heat maps were generated to identify responders for each muscle group. Responders were considered patients that had a > 50% change in RMS over baseline.

Results: We demonstrated greater motor responses across medial and lateral contacts and greater responder rates consistently at the T6 and T9 levels with HR-SCS as compared to commercial paddles in 18 patients. Distal muscle groups (gastrocnemius and tibialis anterior) were selectively activated at both levels while proximal muscle activation (biceps femoris) was limited to T9.

Conclusion : We demonstrate that HR-SCS has greater selectivity in eliciting evoked EMG responses in an intraoperative setting. HR-SCS offers recruitment of muscle groups at lateral contacts concurrently with medial contacts. We provide data that HR–SCS may provide higher spatial resolution which has the potential to allow for personalization of care and treatment of pain syndromes/symptoms which to date have not been effectively treated.