ID# 1906237 First Objective Quantification of Multifidus Activity during Restorative Stimulation using 18F-FDG PET/CT- Mechanisms of action
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Authors
Poply K.
Harron A.
Wodehouse T.
Ganeshan B.
Endozo R.
Goss B.
Mehta, V.
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2025
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Introduction: Background: Restorative neurostimulation for chronic mechanical low back pain relies on stimulation of the L2 medial branch of the dorsal ramus to elicit episodic tetanic contractions of lumbar multifidus muscle. Longitudinal clinical 5-year data supports improvements in pain and quality of life indices.1 Objectives of this study were to provide quantification of metabolic activity and heterogeneity using PET uptake measurements and radiomic-based texture analysis on 18F-FDG PET/CT to uniquely visualize and quantify changes in segmental and full lumbo-sacral multifidus and paraspinal muscle lengths in response to restorative neurostimulation therapy. Method(s): Methods: After regulatory approval (Clinicaltrials.gov: NCT04327817 and Rec 20/LO/0740), seven patients underwent three 18F-FDG PET/CT scans (GE-Discovery 710 PET system, 128 slice CT (approx. 250 MBq i.v)) which were acquired at baseline, six months, and one year following multifidus stimulator implant. Baseline scans were performed in a resting position. Six-month and 12-month scans were obtained immediately after a 30-minute multifidus stimulation session. Metabolic activity within the brain and multifidus was quantified using maximum standardized uptake values (SUVmax). Multifidus muscle low dose CT texture analysis (CTTA) was performed to examine changes in heterogeneity within the multifidus muscles (using entropy as a parameter reflecting irregularity at pixel resolution). Result(s): Results: Regions of interest specific to deep multifidi showed increased 18F-FDG uptake (SUVmax) (p< 0.001) between baseline and post-stimulation scans at six and 12 months within deep multifidi from L2 to L5. CTTA was available in the first four patients who had pre-stimulation and 6-month post-stimulation scans as part of a preliminary exploratory analysis. CTTA was significantly different (p=0.004) between post- and pre-stimulation within deep paraspinal muscles and was higher (median value=4.12, range: 3.53-4.39) in post-stimulation compared to pre-stimulation (median value=3.81, range: 3.43-4.33). Prospective correlation for 12-month follow-up data will be provided. Conclusion(s): Conclusion(s): This analysis demonstrated mechanistic understanding of structural and metabolic changes in multifidi as a direct consequence of stimulation. Metabolic activation observed in L2-L5 and textural changes in the muscle are consistent with animal studies demonstrating histological structural changes.2 This is the first long-term quantification of muscle function and texture demonstrating an increased metabolic activity (18FDG uptake and texture analysis) following stimulation of the L2 medial branch of the dorsal ramus. These data help contribute to explanations regarding specific aspects of a restorative mechanism and are consistent with both electrophysiological and histological findings.3 Copyright © 2025
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Neuromodulation
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The Abstract from The Irish Society of Urology Annual Meeting 10 and 11 October 2025 Radisson Blu Hotel, Sligo Publication; ISU 2025 Annual Abstract.