Spinal cord injury (SCI) is a devastating condition that results in paralysis and significant functional impairments for approximately one million individuals globally, with new cases growing each year. The consequences of SCI extend beyond motor and sensory deficits to include muscle atrophy, spasticity, heterotopic ossification, and disturbances in autonomic function, profoundly diminishing patients’ quality of life. Despite advances in medicine, current therapeutic strategies remain predominantly focused on rehabilitation through medication, physical therapy, and surgical interventions, none of which reliably reverse the neural damage inflicted by SCI. Recently, epidural electrical stimulation (EES) has garnered attention as a promising neurorehabilitation approach by leveraging implanted electrodes in the epidural space to activate spinal neural circuits below the lesion, enhancing network excitability and facilitating recovery of motor and sensory functions, as evidenced in prior animal and clinical models.
However, the effects of EES on patients with incomplete SCI have yet to be conclusively established. Current evidence is limited by small sample sizes, variable long-term outcomes, and a narrow focus primarily on motor recovery. Furthermore, delineating the individual contributions of EES from concurrent physical therapy (PT) presents a critical methodological challenge, as their combined efficacy remains underexplored in controlled clinical contexts. Addressing this gap, researchers at Beijing Tiantan Hospital, Capital Medical University, led by Yihang Ren, designed a controlled, larger cohort study to rigorously evaluate the impact of EES combined with standardized PT across multiple neurological domains, encompassing sensation, muscle strength, spasticity, and autonomic functions in individuals with incomplete SCI.
The single-center, nonrandomized, and nonblinded cohort study spanned from October 2020 to April 2024, enrolling adult patients with incomplete spinal cord injuries classified by the ASIA grading system (grade ≥B) and injury levels above L1–L2, at least six months post-injury. Rigorous baseline assessments were conducted, including MRI, electromyography (EMG), somatosensory evoked potentials (SEP), and computed tomography (CT), to characterize demographic, clinical, and radiological profiles. Participants self-selected into an intervention group receiving EES plus PT (n=11) or a control group undergoing PT alone (n=10). Both groups engaged in an intensive, standardized physical therapy regimen focused on lower-limb functional training, cycling, quadriceps strengthening, ankle passive motion, and body-weight-supported treadmill exercises for 4–5 hours daily, supplemented by remote follow-up.
In the intervention arm, the surgical protocol involved implantation of a thoracolumbar epidural electrode (Medtronic 39565) connected initially to a temporary stimulator (Medtronic 37714), with intraoperative electrophysiological monitoring ensuring optimal electrode placement and stimulation parameter calibration—namely anode/cathode configuration, amplitude, pulse width, and frequency. Following a 7–10-day evaluation period confirming therapeutic benefit without adverse effects, permanent implantable stimulators (Medtronic 37714) were implanted subcutaneously. Stimulation protocols commenced on the first postoperative day, targeting major lower-limb muscle groups with iterative adjustments over two weeks. Patients were assessed at three timepoints: baseline, within 14 days post-EES surgery prior to PT commencement, and at a long-term follow-up between 19 and 25 months.
Comparative analyses revealed no significant difference between groups at baseline in demographics, injury characteristics, or neurological status (all P>0.05), validating internal comparability. Early postoperative evaluation at day 14 in EES+PT patients demonstrated marked improvements in sensory function and reduction in muscle spasticity (both P<0.001), although group-level changes in lower-limb strength, urinary and bowel function, and pain scores did not reach statistical significance. Notably, individual patient data indicated that roughly one-third exhibited enhanced muscle strength, and the majority experiencing neuropathic pain reported symptom alleviation.
Longitudinal outcomes over 19–25 months substantiated sustained and significant gains in the intervention group across multiple domains. EES combined with PT facilitated robust improvements in sensory scores, spasticity reduction, and urinary control (P<0.001 and P<0.05 respectively). Remarkably, 100% of EES+PT participants exhibited enhanced sensation and spasticity metrics, while substantial proportions also improved in urinary (6/11), motor strength (4/11), bowel function (4/11), and pain relief (4/5) parameters. In direct comparisons, EES+PT significantly outperformed PT alone in sensory, motor, spasticity, and urinary functions (P-values ranging from <0.01 to <0.0001). Although bowel function improvement favored the EES+PT group (57.1% recovery vs. 11.1% in PT-only), this result did not achieve statistical significance. Encouragingly, no electrode-related infections or displacements were reported throughout the follow-up period.
This pioneering investigation offers compelling evidence that EES integrated with standardized physical therapy yields considerable long-term benefits for patients with incomplete SCI, encompassing sensory restoration, strength augmentation, spasticity management, and autonomic improvements such as urinary control. The study also highlights potential advantages in bladder function and neuropathic pain relief, broadening the therapeutic scope of EES beyond motor recovery alone. The implant technology, paired with personalized stimulation protocols, appears safe and well-tolerated, setting the stage for broader clinical adoption.
Looking forward, the authors emphasize the importance of further research incorporating controlled rehabilitation content and intensity, extended follow-up durations to evaluate sustainability, and objective sensory assessments including electrophysiological measurements. Unraveling the underlying neuroplasticity mechanisms will enrich the understanding of EES’s role in spinal network reorganization. Moreover, controlling for confounding variables like age and comorbidities, and comparing EES+PT against alternative treatments in randomized designs, will be essential to conclusively reaffirm its efficacy. Personalized treatment paradigms tailored to individual patient profiles are envisioned to optimize therapeutic outcomes.
The investigative team includes Yihang Ren, Lifen Mo, Junlin Lu, Ping Zhu, Ming Yin, Wenqing Jia, Fengyan Liang, Xiaodi Han, and Jizong Zhao, and their groundbreaking work is detailed in the paper entitled “Epidural Electrical Stimulation for Functional Recovery in Incomplete Spinal Cord Injury.” Published in the journal Cyborg and Bionic Systems on July 22, 2025, this study underscores significant advancements in neurorehabilitation strategies for SCI. Supported by prestigious funding bodies such as the National Natural Science Foundation of China and regional technology science initiatives, this research marks a critical milestone in spinal injury therapeutics.
As spinal cord injury continues to challenge neuroscience and rehabilitation disciplines, this study offers a beacon of progress. By combining cutting-edge neuromodulation technology with rigorous physical therapy, EES emerges as a transformative approach capable of restoring multiple functional domains lost to SCI. The implications for clinical practice, patient quality of life, and future innovation in neurorehabilitation are profound, inviting further exploration and rapid translation of these findings into widespread clinical settings.
Subject of Research: Epidural electrical stimulation combined with physical therapy for functional recovery in incomplete spinal cord injury
Article Title: Epidural Electrical Stimulation for Functional Recovery in Incomplete Spinal Cord Injury
News Publication Date: July 22, 2025
Web References: DOI: 10.34133/cbsystems.0314
Image Credits: Yihang Ren, Beijing Tiantan Hospital, Capital Medical University
Keywords: Life sciences, Mathematics, Physical sciences
