Redistribution of Intraspinal and Muscular 18F-FDG Uptake after the Epidural Electrical Stimulation Treatment in Spinal Cord Injury Individuals

Purpose: This study investigates the redistribution of resting 18 F-Fluorodeoxyglucose ( 18 F-FDG) uptake in both spinal cord and lower limb muscles following 6 months of epidural electrical stimulation (EES) treatment in spinal cord injury (SCI) individuals, examining potential implications for metabolic and functional recovery. Materials and Methods: A clinical trial (NCT04969042) was conducted to improve lower limb motor function using EES. Resting 18 F-FDG Positron Emission Tomography–Computed Tomography (PET/CT) was performed before EES implantation and after 6 months of EES treatment. Metabolic changes were assessed in both the spinal cord and lower limb muscles. Results: After 6 months of EES treatment, the motor function of the lower limbs gradually recovers. EES can synergistically activate the muscles to form a rhythmic gait. Increased intraspinal 18 F-FDG uptake was observed in the EES-implanted region, while a decrease was noted in nonstimulated segments, indicating a redistribution of spinal cord 18 F-FDG uptake. In addition, muscle cross-sectional total glycolysis (TLG) increased in the lower limbs. The TLG increased by 19.84% in the psoas major, by 30.67% in the iliacus muscle, and by 9.78% in the thigh muscles. Conclusions: EES promotes localized 18 F-FDG uptake at stimulated intraspinal region and lower limb muscles, suggesting potential as a targeted metabolic intervention for motor recovery in SCI and related metabolic dysfunctions.