Spinal cord injury (SCI) causes paralysis in roughly one million people worldwide, with incident cases rising yearly. Beyond motor and sensory deficits, patients frequently experience muscle atrophy, spasticity, heterotopic ossification, and autonomic dysfunction, all of which severely impair quality of life. Current treatments are rehabilitation-centered; medications, physical therapies, and surgery rarely reverse neural damage. In recent years, epidural electrical stimulation (EES) has emerged as a neurorehabilitation approach. Prior animal and clinical studies suggest that EES, delivered via electrodes implanted in the epidural space, activates neural circuits below the lesion and increases network excitability, which can elicit standing/locomotor patterns and promote recovery of sensory and motor functions. “However, for people with incomplete SCI, evidence for EES’s effectiveness on functional recovery remains limited: small sample sizes, uncertain long-term outcomes, a predominant focus on motor function, and difficulty separating the effects of concurrent physical therapy (PT). The combined effects of EES and PT have not been tested in controlled designs.” said the author Yihang Ren, a researcher at Beijing Tiantan Hospital, Capital Medical University, “Therefore, we propose a comparatively larger, controlled cohort study to systematically evaluate EES plus PT across multiple outcome domains—sensation, muscle strength, spasticity, and autonomic function—in individuals with incomplete SCI.”
This single-center, nonrandomized, nonblinded controlled cohort study at Beijing Tiantan Hospital (October 2020–April 2024) was approved by the institutional ethics committee (Approval No. KY 2021-012-02) with written informed consent from all participants. Eligible adults had incomplete spinal cord injury (ASIA grade ≥B), an injury level above L1–L2, and were ≥6 months postinjury; demographic, clinical, and radiological baselines (MRI, EMG/SEP, and CT) were obtained preoperatively. Patients self-selected into an intervention arm (EES + PT; n=11) or a comparison arm (PT only; n=10). All patients received standardized physical therapy comprising lower-limb functional training, rehabilitation cycling, quadriceps strengthening, ankle continuous passive motion, and body-weight-supported treadmill work for 4–5 hours daily with remote follow-up. In the intervention arm, surgery entailed implantation of a thoracolumbar epidural electrode (Medtronic 39565) with a temporary stimulator (Medtronic 37714); intraoperative electrophysiological monitoring guided electrode positioning and initial parameter selection (anode/cathode configuration, amplitude, pulse width, frequency). If a favorable response and no adverse effects were confirmed after 7–10 days, an implantable stimulator (Medtronic 37714) was placed via subcutaneous tunneling. Stimulation protocols were configured beginning postoperative day 1 to ensure coverage of major lower-limb muscle groups. Outcomes were assessed at three time points—baseline, within 14 days post-EES surgery, and at 19–25 months—and included ASIA sensory scores (C2–S5; total 224), ASIA motor scores (L2–S1), Modified Ashworth Spasticity Scale, urinary and bowel function composites, and visual-analog pain ratings.
In this nonrandomized cohort (EES+PT, n=11; PT-only, n=10), baseline demographics, injury characteristics, and initial neurological measures did not differ between groups (all P>0.05), supporting internal comparability. Short-term effects were assessed on postoperative day 14 while patients were bedbound and had not yet begun PT: in the EES+PT arm, sensation and muscle spasticity improved significantly (both P<0.001), whereas group-level changes in strength, urinary and bowel function, and pain were not significant; nevertheless, 4/11 improved lower-limb strength and 4/5 with neuropathic pain reported lower scores. Over long-term follow-up (19–25 months), within-group analyses for EES+PT showed significant gains in sensation (P<0.001), spasticity (P<0.001), and urinary control (P<0.05), with all 11 improving in sensation/spasticity, 6/11 in urinary control, 4/11 in strength, 4/11 in bowel function, and 4/5 in pain. Between-group comparisons at the same horizon favored EES+PT over PT-only for sensory function (P<0.01), strength (P<0.01), spasticity (P<0.0001), and urinary control (P<0.01); bowel outcomes showed a higher recovery rate with EES+PT (57.1% vs 11.1%) but did not reach statistical significance. No electrode-related infections or displacements occurred among the 11 implanted patients during follow-up.
This study comprehensively evaluated the combined effects of EES and PT on sensory, motor, and autonomic functions in SCI patients. The results indicate that EES combined with PT significantly enhances long-term sensory function, muscle strength, spasticity, and urinary function in SCI patients compared to PT alone. The combined treatment also improved bladder control and pain relief in some patients. “In the future, we will conduct single-center studies to control the content and intensity of rehabilitation. We will evaluate the long-term sustainability of rehabilitation based on a longer follow-up period. Incorporating objective sensory measurements, such as electrophysiological measurement, and exploring neuroplasticity mechanisms will enhance understanding. Controlling for confounding factors such as age and comorbidities and comparing EES + PT with other interventions will validate its efficacy. Finally, we will customize treatment plans based on individual patient needs to maximize treatment effectiveness.” said Yihang Ren.
Authors of the paper include Yihang Ren, Lifen Mo, Junlin Lu, Ping Zhu, Ming Yin, Wenqing Jia, Fengyan Liang, Xiaodi Han, and Jizong Zhao.
This research was supported by the National Natural Science Foundation of China (Nos. T2488101, 32360196, and 32160204), the Project of Sanya Yazhou Bay Science and Technology City (Nos. SCKJ-JYRC-2023-26 and SCKJ-JYRC-2023-27), the Key R&D Project of Hainan Province (Grant Nos. ZDYF2025SHFZ023, ZDYF2022SHFZ302, and ZDYF2022SHFZ275), and the South China Sea Rising Star Project of Hainan Province and Hunan Provincial Natural Science Foundation of China (No. 2025JJ90272).
The paper, “Epidural Electrical Stimulation for Functional Recovery in Incomplete Spinal Cord Injury” was published in the journal Cyborg and Bionic Systems on Jul. 22, 2025, at DOI: 10.34133/cbsystems.0314.
Spinal cord injury (SCI) causes paralysis in roughly one million people worldwide, with incident cases rising yearly. Beyond motor and sensory deficits, patients frequently experience muscle atrophy, spasticity, heterotopic ossification, and autonomic dysfunction, all of which severely impair quality of life. Current treatments are rehabilitation-centered; medications, physical therapies, and surgery rarely reverse neural damage. In recent years, epidural electrical stimulation (EES) has emerged as a neurorehabilitation approach. Prior animal and clinical studies suggest that EES, delivered via electrodes implanted in the epidural space, activates neural circuits below the lesion and increases network excitability, which can elicit standing/locomotor patterns and promote recovery of sensory and motor functions. “However, for people with incomplete SCI, evidence for EES’s effectiveness on functional recovery remains limited: small sample sizes, uncertain long-term outcomes, a predominant focus on motor function, and difficulty separating the effects of concurrent physical therapy (PT). The combined effects of EES and PT have not been tested in controlled designs.” said the author Yihang Ren, a researcher at Beijing Tiantan Hospital, Capital Medical University, “Therefore, we propose a comparatively larger, controlled cohort study to systematically evaluate EES plus PT across multiple outcome domains—sensation, muscle strength, spasticity, and autonomic function—in individuals with incomplete SCI.”
This single-center, nonrandomized, nonblinded controlled cohort study at Beijing Tiantan Hospital (October 2020–April 2024) was approved by the institutional ethics committee (Approval No. KY 2021-012-02) with written informed consent from all participants. Eligible adults had incomplete spinal cord injury (ASIA grade ≥B), an injury level above L1–L2, and were ≥6 months postinjury; demographic, clinical, and radiological baselines (MRI, EMG/SEP, and CT) were obtained preoperatively. Patients self-selected into an intervention arm (EES + PT; n=11) or a comparison arm (PT only; n=10). All patients received standardized physical therapy comprising lower-limb functional training, rehabilitation cycling, quadriceps strengthening, ankle continuous passive motion, and body-weight-supported treadmill work for 4–5 hours daily with remote follow-up. In the intervention arm, surgery entailed implantation of a thoracolumbar epidural electrode (Medtronic 39565) with a temporary stimulator (Medtronic 37714); intraoperative electrophysiological monitoring guided electrode positioning and initial parameter selection (anode/cathode configuration, amplitude, pulse width, frequency). If a favorable response and no adverse effects were confirmed after 7–10 days, an implantable stimulator (Medtronic 37714) was placed via subcutaneous tunneling. Stimulation protocols were configured beginning postoperative day 1 to ensure coverage of major lower-limb muscle groups. Outcomes were assessed at three time points—baseline, within 14 days post-EES surgery, and at 19–25 months—and included ASIA sensory scores (C2–S5; total 224), ASIA motor scores (L2–S1), Modified Ashworth Spasticity Scale, urinary and bowel function composites, and visual-analog pain ratings.
In this nonrandomized cohort (EES+PT, n=11; PT-only, n=10), baseline demographics, injury characteristics, and initial neurological measures did not differ between groups (all P>0.05), supporting internal comparability. Short-term effects were assessed on postoperative day 14 while patients were bedbound and had not yet begun PT: in the EES+PT arm, sensation and muscle spasticity improved significantly (both P<0.001), whereas group-level changes in strength, urinary and bowel function, and pain were not significant; nevertheless, 4/11 improved lower-limb strength and 4/5 with neuropathic pain reported lower scores. Over long-term follow-up (19–25 months), within-group analyses for EES+PT showed significant gains in sensation (P<0.001), spasticity (P<0.001), and urinary control (P<0.05), with all 11 improving in sensation/spasticity, 6/11 in urinary control, 4/11 in strength, 4/11 in bowel function, and 4/5 in pain. Between-group comparisons at the same horizon favored EES+PT over PT-only for sensory function (P<0.01), strength (P<0.01), spasticity (P<0.0001), and urinary control (P<0.01); bowel outcomes showed a higher recovery rate with EES+PT (57.1% vs 11.1%) but did not reach statistical significance. No electrode-related infections or displacements occurred among the 11 implanted patients during follow-up.
This study comprehensively evaluated the combined effects of EES and PT on sensory, motor, and autonomic functions in SCI patients. The results indicate that EES combined with PT significantly enhances long-term sensory function, muscle strength, spasticity, and urinary function in SCI patients compared to PT alone. The combined treatment also improved bladder control and pain relief in some patients. “In the future, we will conduct single-center studies to control the content and intensity of rehabilitation. We will evaluate the long-term sustainability of rehabilitation based on a longer follow-up period. Incorporating objective sensory measurements, such as electrophysiological measurement, and exploring neuroplasticity mechanisms will enhance understanding. Controlling for confounding factors such as age and comorbidities and comparing EES + PT with other interventions will validate its efficacy. Finally, we will customize treatment plans based on individual patient needs to maximize treatment effectiveness.” said Yihang Ren.
Authors of the paper include Yihang Ren, Lifen Mo, Junlin Lu, Ping Zhu, Ming Yin, Wenqing Jia, Fengyan Liang, Xiaodi Han, and Jizong Zhao.
This research was supported by the National Natural Science Foundation of China (Nos. T2488101, 32360196, and 32160204), the Project of Sanya Yazhou Bay Science and Technology City (Nos. SCKJ-JYRC-2023-26 and SCKJ-JYRC-2023-27), the Key R&D Project of Hainan Province (Grant Nos. ZDYF2025SHFZ023, ZDYF2022SHFZ302, and ZDYF2022SHFZ275), and the South China Sea Rising Star Project of Hainan Province and Hunan Provincial Natural Science Foundation of China (No. 2025JJ90272).
The paper, “Epidural Electrical Stimulation for Functional Recovery in Incomplete Spinal Cord Injury” was published in the journal Cyborg and Bionic Systems on Jul. 22, 2025, at DOI: 10.34133/cbsystems.0314.
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