Epidural Spinal Cord Stimulation Research Articles

Timing-dependent synergies between motor cortex and posterior spinal stimulation in humans.

Volitional movement requires descending input from the motor cortex and sensory feedback through the spinal cord. We previously developed a paired brain and spinal electrical stimulation approach in rats that relies on convergence of the descending motor and spinal sensory stimuli in the cervical cord. This approach strengthened sensorimotor circuits and improved volitional movement through associative plasticity. In humans, it is not known whether posterior epidural spinal cord stimulation targeted at the sensorimotor interface or anterior epidural spinal cord stimulation targeted within the motor system is effective at facilitating brain evoked responses. In 59 individuals undergoing elective cervical spine decompression surgery, the motor cortex was stimulated with scalp electrodes and the spinal cord was stimulated with epidural electrodes, with muscle responses being recorded in arm and leg muscles. Spinal electrodes were placed either posteriorly or anteriorly, and the interval between cortex and spinal cord stimulation was varied. Pairing stimulation between the motor cortex and spinal sensory (posterior) but not spinal motor (anterior) stimulation produced motor evoked potentials that were over five times larger than brain stimulation alone. This strong augmentation occurred only when descending motor and spinal afferent stimuli were timed to converge in the spinal cord. Paired stimulation also increased the selectivity of muscle responses relative to unpaired brain or spinal cord stimulation. Finally, clinical signs suggest that facilitation was observed in both injured and uninjured segments of the spinal cord. The large effect size of this paired stimulation makes it a promising candidate for therapeutic neuromodulation. KEY POINTS: Pairs of stimuli designed to alter nervous system function typically target the motor system, or one targets the sensory system and the other targets the motor system for convergence in cortex. In humans undergoing clinically indicated surgery, we tested paired brain and spinal cord stimulation that we developed in rats aiming to target sensorimotor convergence in the cervical cord. Arm and hand muscle responses to paired sensorimotor stimulation were more than five times larger than brain or spinal cord stimulation alone when applied to the posterior but not anterior spinal cord. Arm and hand muscle responses to paired stimulation were more selective for targeted muscles than the brain- or spinal-only conditions, especially at latencies that produced the strongest effects of paired stimulation. Measures of clinical evidence of compression were only weakly related to the paired stimulation effect, suggesting that it could be applied as therapy in people affected by disorders of the central nervous system.

Lumbar epidural electrical stimulation enhances respiration in mice

Spinal cord epidural electrical stimulation (EES) has emerged as a novel approach to modulate and interrogate the neural circuit(s) underlying sensorimotor functions in the past few decades. Recent studies have revealed that cervical EES can regulate respiration in both human subjects and animal models. Furthermore, coupled cervical and lumbar stimulations significantly increased the rhythmic motor outputs in both the cervical and lumbar spinal cord. We hypothesize that the lumbar and cervical coupling is underpinned by cervico-lumbar synaptic connections, and thus, EES at level of the lumbar spinal cord alone may also facilitate respiration via the cervico-lumbar circuit. In this study, we applied EES to the dorsal surface of the lumbar spinal cord between levels 1 and 6 (L1-6) in anesthetized mice. We found that rostral lumbar (L1-2) EES at a stimulation intensity of 0.5 mA elicited significantly higher respiratory frequency, tidal volume, and minute ventilation responses compared to the other lumbar levels (L3-4 and L5-6) tested at intensities ranging from 0.1-1.0 mA. The increased respiratory activity elicited by lumbar stimulation persisted even after the stimulation ceased. Using the optimal stimulation parameters that we identified, we further investigated the underlying mechanism of the lumbar EES-induced respiratory response by examining the neuronal activation patterns. Using immunostaining, we detected c-fos signals, a marker of neuronal activity, in the cervical spinal cord and brainstem after EES at L1-2 using 0.5 mA at 30Hz. This indicates that focal lumbar stimulation elicits remote neuronal activation in cervical spinal cord and brainstem, regions that contain respiration-related neural circuits. These findings suggest that lumbar EES may facilitate respiration by recruiting paraspinal respiratory circuits and potentially supra-spinal respiratory central pattern generator(s). This study provides insights into the development of novel approaches to restore normal respiratory patterns for patients with respiratory disorders, particularly spinal cord injuries. This work was supported by The Louis and Harold Price Foundation, H & H Evergreen Foundation, Jonathan and Susan Dolgen Foundation, the National Institute of Drug Abuse (R01DA047637), and the National Institute of Neurological Disorders and Stroke (UH3NS119772) in the National Institutes of Health. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Robotic Postural Training With Epidural Stimulation for the Recovery of Upright Postural Control in Individuals With Motor Complete Spinal Cord Injury: A Pilot Study.

Activity-based training and lumbosacral spinal cord epidural stimulation (scES) have the potential to restore standing and walking with self-balance assistance after motor complete spinal cord injury (SCI). However, improvements in upright postural control have not previously been addressed in this population. Here, we implemented a novel robotic postural training with scES, performed with free hands, to restore upright postural control in individuals with chronic, cervical (n = 5) or high-thoracic (n = 1) motor complete SCI, who had previously undergone stand training with scES using a walker or a standing frame for self-balance assistance. Robotic postural training re-enabled and/or largely improved the participants' ability to control steady standing, self-initiated trunk movements and upper limb reaching movements while standing with free hands, receiving only external assistance for pelvic control. These improvements were associated with neuromuscular activation pattern adaptations above and below the lesion. These findings suggest that the human spinal cord below the level of injury can generate meaningful postural responses when its excitability is modulated by scES, and can learn to improve these responses. Upright postural control improvements can enhance functional motor recovery promoted by scES after severe SCI.

Peak Slope Ratio of the Recruitment Curves Compared to Muscle Evoked Potentials to Optimize Standing Configurations with Percutaneous Epidural Stimulation after Spinal Cord Injury.

Background: Percutaneous spinal cord epidural stimulation (pSCES) has effectively restored varying levels of motor control in persons with motor complete spinal cord injury (SCI). Studying and standardizing the pSCES configurations may yield specific motor improvements. Previously, reliance on the amplitude of the SCES-evoked potentials (EPs) was used to determine the correct stimulation configurations. Methods: We, hereby, retrospectively examined the effects of wide and narrow-field configurations on establishing the motor recruitment curves of motor units of three different agonist-antagonist muscle groups. Magnetic resonance imaging was also used to individualize SCI participants (n = 4) according to their lesion characteristics. The slope of the recruitment curves using a six-degree polynomial function was calculated to derive the slope ratio for the agonist-antagonist muscle groups responsible for standing. Results: Axial damage ratios of the spinal cord ranged from 0.80 to 0.92, indicating at least some level of supraspinal connectivity for all participants. Despite the close range of these ratios, standing motor performance was enhanced using different stimulation configurations in the four persons with SCI. A slope ratio of ≥1 was considered for the recommended configurations necessary to achieve standing. The retrospectively identified configurations using the supine slope ratio of the recruitment curves of the motor units agreed with that visually inspected muscle EPs amplitude of the extensor relative to the flexor muscles in two of the four participants. Two participants managed to advance the selected configurations into independent standing performance after using tonic stimulation. The other two participants required different levels of assistance to attain standing performance. Conclusions: The findings suggest that the peak slope ratio of the muscle agonists-antagonists recruitment curves may potentially identify the pSCES configurations necessary to achieve standing in persons with SCI.

Retrograde Epidural Spinal Cord Stimulation for the Treatment of Intractable Neuropathic Pain Following Spinal Cord and Cauda Equina Injuries: A Case Report and Literature Review

AbstRactSpinal cord stimulation (SCS) offers an alternative treatment for refractory pain resulting from various etiologies. Generally, SCS electrodes are inserted in an anterograde fashion, moving from caudal to rostral direction. However, there are instances where anterograde placement is unfeasible due to technical limitations. We present the use of retrograde surgical electrode placement in SCS for a patient with extensive epidural fibrosis at the site intended for electrode insertion. A 48-year-old female suffering from refractory neuropathic pain caused from injuries to the conus medullaris and cauda equina opted for SCS. During the SCS trial procedure, challenges emerged when attempting percutaneous electrode insertion at the site of a prior T12 laminectomy. However, the trial stimulation resulted in significant pain relief. For the permanent placement of the stimulator, utilizing a surgical electrode centered at T11 vertebral level, a considerable amount of epidural fibrosis was encountered at the entry of the spine, particularly at the T12 vertebral level. To avoid dural injury and ensure accurate electrode positioning, a retrograde technique for surgical electrode was employed via partial laminectomies at the T9-T10 level. The final electrode positioning was in accordance with the preoperative plan, well-centered at the T11 vertebral level. The patient experienced sustained relief from neuropathic pain over the long term. Retrograde epidural SCS is a suitable option for cases characterized by extensive epidural fibrosis resulting from a previous spinal surgery or when the anterograde placement of the electrode is unattainable due to aberrant vertebral anatomy.

Epidural Spinal Cord Stimulation for Spinal Cord Injury in Humans: A Systematic Review.

(1) Background: Spinal cord injury (SCI) represents a major health challenge, often leading to significant and permanent sensorimotor and autonomic dysfunctions. This study reviews the evolving role of epidural spinal cord stimulation (eSCS) in treating chronic SCI, focusing on its efficacy and safety. The objective was to analyze how eSCS contributes to the recovery of neurological functions in SCI patients. (2) Methods: We utilized the PRISMA guidelines and performed a comprehensive search across MEDLINE/PubMed, Embase, Web of Science, and IEEE Xplore databases up until September 2023. We identified studies relevant to eSCS in SCI and extracted assessments of locomotor, cardiovascular, pulmonary, and genitourinary functions. (3) Results: A total of 64 studies encompassing 306 patients were identified. Studies investigated various stimulation devices, parameters, and rehabilitation methods. Results indicated significant improvements in motor function: 44% of patients achieved assisted or independent stepping or standing; 87% showed enhanced muscle activity; 65% experienced faster walking speeds; and 80% improved in overground walking. Additionally, eSCS led to better autonomic function, evidenced by improvements in bladder and sexual functions, airway pressures, and bowel movements. Notable adverse effects included device migration, infections, and post-implant autonomic dysreflexia, although these were infrequent. (4) Conclusion: Epidural spinal cord stimulation is emerging as an effective and generally safe treatment for chronic SCI, particularly when combined with intensive physical rehabilitation. Future research on standardized stimulation parameters and well-defined therapy regimens will optimize benefits for specific patient populations.

Symptomatic Treatment of Myelopathy.

This article discusses the effects of myelopathy on multiple organ systems and reviews the treatment and management of some of these effects. Recent advances in functional electrical stimulation, epidural spinal cord stimulation, robotics, and surgical techniques such as nerve transfer show promise in improving function in patients with myelopathy. Ongoing research in stem cell therapy and neurotherapeutic drugs may provide further therapeutic avenues in the future. Treatment for symptoms of spinal cord injury should be targeted toward patient goals. If nerve transfer for upper extremity function is considered, the patient should be evaluated at around 6 months from injury to assess for lower motor neuron involvement and possible time limitations of surgery. A patient with injury at or above the T6 level is at risk for autonomic dysreflexia, a life-threatening condition that presents with elevated blood pressure and can lead to emergent hypertensive crisis. Baclofen withdrawal due to baclofen pump failure or programming errors may also be life-threatening. Proper management of symptoms may help avoid complications such as autonomic dysreflexia, renal failure, heterotopic ossification, and fractures.

Spinal cord stimulation for chronic pain treatment following sacral chordoma resection: illustrative case.

Cancer-related or postoperative pain can occur following sacral chordoma resection. Despite a lack of current recommendations for cancer pain treatment, spinal cord stimulation (SCS) has demonstrated effectiveness in addressing cancer-related pain. A 76-year-old female with a sacral chordoma underwent anterior osteotomies and partial en bloc sacrectomy. She subsequently presented with chronic pain affecting both buttocks and posterior thighs and legs, significantly impeding her daily activities. She underwent a staged epidural SCS paddle trial and permanent system placement using intraoperative neuromonitoring. The utilization of percutaneous leads was not viable because of her history of spinal fluid leakage, multiple lumbosacral surgeries, and previous complex plastic surgery closure. The patient reported a 62.5% improvement in her lower-extremity pain per the modified Quadruple Visual Analog Scale and a 50% improvement in the modified Pain and Sleep Questionnaire 3-item index during the SCS trial. Following permanent SCS system placement and removal of her externalized lead extenders, she had an uncomplicated postoperative course and reported notable improvements in her pain symptoms. This case provides a compelling illustration of the successful treatment of chronic pain using SCS following radical sacral chordoma resection. Surgeons may consider this treatment approach in patients presenting with refractory pain following spinal tumor resection.

Standing Reactive Postural Responses of Lower Limbs With and Without Self-Balance Assistance in Individuals With Spinal Cord Injury Receiving Epidural Stimulation.

Spinal cord epidural stimulation can promote the recovery of motor function in individuals with severe spinal cord injury (SCI) by enabling the spinal circuitry to interpret sensory information and generate related neuromuscular responses. This approach enables the spinal cord to generate lower limb extension patterns during weight bearing, allowing individuals with SCI to achieve upright standing. We have shown that the human spinal cord can generate some standing postural responses during self-initiated body weight shifting. In this study, we investigated the ability of individuals with motor complete SCI receiving epidural stimulation to generate standing reactive postural responses after external perturbations were applied at the trunk. A cable-driven robotic device was used to provide constant assistance for pelvic control and to deliver precise trunk perturbations while participants used their hands to grasp onto handlebars for self-balance support (hands-on) as well as when participants were without support (free-hands). Five individuals with motor complete SCI receiving lumbosacral spinal cord epidural stimulation parameters specific for standing (Stand-scES) participated in this study. Trunk perturbations (average magnitude: 17 ± 3% body weight) were delivered randomly in the four cardinal directions. Participants attempted to control each perturbation such that upright standing was maintained and no additional external assistance was needed. Lower limb postural responses were generally more frequent, larger in magnitude, and appropriately modulated during the free-hands condition. This was associated with trunk displacement and lower limb loading modulation that were larger in the free-hands condition. Further, we observed discernible lower limb muscle synergies that were similar between the two perturbed standing conditions. These findings suggest that the human spinal circuitry involved in postural control retains the ability to generate meaningful lower limb postural responses after SCI when its excitability is properly modulated. Moreover, lower limb postural responses appear enhanced by a standing environment without upper limb stabilization that promotes afferent inputs associated with a larger modulation of ground reaction forces and trunk kinematics. These findings should be considered when developing future experimental frameworks aimed at studying upright postural control and activity-based recovery training protocols aimed at promoting neural plasticity and sensory-motor recovery.

Current strategies for regenerative therapy of spinal cord injury

Spinal cord injury (SCI) is a leading cause of death and severe disability amongst young people. The incidence of SCI is 0.6–1.0 per 10,000 individuals. Unfortunately, there are no effective methods of restoring locomotor function for individuals with severe SCI. To address this issue, exoskeleton technology controlled using BCI is actively being developed for prosthetic locomotion. Despite the lack of encouraging data for severe spinal cord injuries, regenerative technologies continue to hold promise for spinal cord repair. The limited options for regenerating the central nervous system in humans necessitate creating new sources of neural stem cells for regeneration. Reprogramming autologous somatic cells neurologically can effectively serve as such a source [1]. Nevertheless, the constitution of neuroglial progenitors, which are necessary for regenerating damaged axons of the pyramidal tract, still requires clarification [2]. Some interesting efforts are underway to directly reprogram glial cells in situ using a variety of biotechnological approaches [3]. Overcoming or preventing the formation of a harsh scar tissue at the injury site is the key obstacle to successful regeneration therapy for SCI. Various scaffolds are being developed to facilitate axon regeneration, and several gene therapy agents are being tested to either knock down scar formation factors or activate extracellular matrix remodeling and reparative regeneration. Neuromodulation shows promise for SCI treatment. Studies indicate that epidural stimulation of the L2-S1 spinal cord in humans and mammals activates SPG neurons, aiding spinal walking generator functions. A potentially successful treatment approach involves scaffolds with reprogrammed cells and neuromodulation [4].

Consecutive Transcutaneous and Epidural Spinal Cord Neuromodulation to Modify Clinical Complete Paralysis—the Proof of Concept

ObjectiveTo evaluate the effect of transcutaneous (tSCS) and epidural electrical spinal cord stimulation (EES) in facilitating volitional movements, balance, and nonmotor functions, in this observational study, tSCS and EES were consecutively tested in 2 participants with motor complete spinal cord injury (SCI). Participants and MethodsTwo participants (a 48-year-old woman and a 28-year-old man), both classified as motor complete spinal injury, were enrolled in the study. Both participants went through a unified protocol, such as an initial electrophysiological assessment of neural connectivity, consecutive tSCS and EES combined with 8 wks of motor training with electromyography (EMG) and kinematic evaluation. The study was conducted from May 1, 2019, to December 31, 2021. ResultsIn both participants, tSCS reported a minimal improvement in voluntary movements still essential to start tSCS-enabled rehabilitation. Compared with tSCS, following EES showed immediate improvement in voluntary movements, whereas tSCS was more effective in improving balance and posture. Continuous improvement in nonmotor functions was found during tSCS-enabled and then during EES-enabled motor training. ConclusionResults report a significant difference in the effect of tSCS and EES on the recovery of neurologic functions and support consecutive tSCS and EES applications as a potential therapy for SCI. The proposed approach may help in selecting patients with SCI responsive to neuromodulation. It would also help initiate neuromodulation and rehabilitation therapy early, particularly for motor complete SCI with minimal effect from conventional rehabilitation.

Spinal cord stimulation in severe pharmacoresistant restless legs syndrome—two case reports

Restless legs syndrome is a prevalent, sleep-related sensorimotor disorder with relevant impact on the patients’ quality of life. For patients suffering from severe, pharmacoresistant restless legs syndrome, few therapeutic options remain to alleviate symptoms. In this case series, two patients with severe, pharmacoresistant restless legs syndrome were treated with epidural spinal cord stimulation and repeatedly assessed with polysomnography, including sleep structure and periodic limb movements as objective biomarkers not subject to placebo effects, during a 6-month follow-up period. One of the patients experienced excellent short- and long-term efficacy on subjective symptom severity (International RLS Study group rating scale 1 vs. 34 points at 3 months) and objective sleep parameters such as sleep architecture and periodic limb movements during sleep, while the second patient only reported short-term benefits from spinal cord stimulation. Ultimately, both patients opted for removal of the device for inefficacy. Based on the complex pathophysiology of restless legs syndrome and presumed mechanism of action of spinal cord stimulation in chronic pain disorders, we provide a detailed hypothesis on the possible modulating effect of spinal cord stimulation on the key symptoms of restless legs syndrome. Apart from describing a new therapeutic option for pharmacoresistant restless legs syndrome, our findings might also provide further insights into the pathophysiology of the syndrome.

Spinal Cord Epidural Stimulation Improves Lower Spine Sitting Posture Following Severe Cervical Spinal Cord Injury.

Cervical spinal cord injury (SCI) leads to impaired trunk motor control, negatively impacting the performance of activities of daily living in the affected individuals. Improved trunk control with better sitting posture has been previously observed due to neuromuscular electrical stimulation and transcutaneous spinal stimulation, while improved postural stability has been observed with spinal cord epidural stimulation (scES). Hence, we studied how trunk-specific scES impacts sitting independence and posture. Fourteen individuals with chronic, severe cervical SCI with an implanted neurostimulator performed a 5-min tall-sit task without and with trunk-specific scES. Spine posture was assessed by placing markers on five spine levels and evaluating vertical spine inclination angles. Duration of trunk manual assistance was used to assess independence along with the number of independence changes and average independence score across those changes. With scES, the sacrum-L1 inclination and number of independence changes tended to decrease by 1.64 ± 3.16° (p = 0.07; Cohen's d = 0.53) and 9.86 ± 16.8 (p = 0.047; Cohen's d = 0.59), respectively. Additionally, for the participants who had poor sitting independence without scES, level of independence tended to increase by 12.91% [0%, 31.52%] (p = 0.38; Cohen's d = 0.96) when scES was present. Hence, trunk-specific scES promoted improvements in lower spine posture and lower levels of trunk assistance.

Student Competition (Knowledge Generation) ID 1985158

Background Spinal cord injury (SCI) affects locomotion and quality of life. Two spinal cord stimulation approaches are currently under investigation for restoring standing and walking following SCI: epidural spinal cord stimulation (ESCS) and intraspinal microstimulation (ISMS). In ESCS, electrodes are placed on the dura mater and in ISMS, ultrafine wires are inserted into the cord. These modalities likely activate the locomotor regions in the ventral horn through different pathways. Objective The goal of this study is to examine the difference in the distribution of neuronal activation and the type of neurons activated by ESCS and ISMS. Methods The first step was to establish the needed immunohistochemical (IHC) staining protocols. Domestic pigs were divided into naïve (n=2) and positive control (n=1) groups. The naïve control animals were anesthetized for 5 hrs. The positive control animal was anesthetized for 2 hrs and injected with hypertonic saline in hindlimb muscles. The animals were then euthanized, and the spinal cord removed for IHC analysis. Antibodies against cFos, a maker of neuronal activation, and NeuN, a neuronal marker were used. Results Preliminary results indicate that ESCS activates neurons in the dorsal horn with scattered activation in the intermediate and ventral regions. ISMS primarily activates neurons in the intermediate and ventral regions where locomotor-related networks reside. Significance To the best of our knowledge, this is the first time the type and sites of activation of ESCS and ISMS are investigated. This will provide a foundational understanding of the mechanism of action of these stimulation modalities.

Student Competition (Knowledge Generation) ID 1985170

Background/Objectives Functional electrical stimulation (FES)-assisted arm and leg (A&L) cycling is an effective rehabilitative intervention for improving walking following an incomplete spinal cord injury (SCI). The goal of this study was to assess the potential benefits of combining transcutaneous spinal cord stimulation (tSCS) with A&L cycling to potentially improve functional mobility and activities of daily living for persons living with motor complete SCI. Methods This is a case study of a participant with AIS B SCI. The participant has been undergoing FES-assisted A&L cycling training combined with cervical and lumbar tSCS (1 hr/day, 5 days/week) for 37 weeks. Assessments were performed pre-training and every 6 weeks thereafter and include the International Standards for Neurological Classification of SCI (ISNCSCI), time able to stand while assisted, and training load of each exercise session. Results Although there were no changes in the ISNCSCI scores, the duration of assisted standing increased from 10s per-training to 33.5s at 36 weeks post-training. Interestingly, the addition of tSCS enhanced standing duration to 38.5s. Moreover, the total power output exerted by the participant consistently increased over time. Conclusion This study provides, for the first time, evidence that FES-assisted A&L cycling paired with non-invasive tSCS can be safely completed after severe SCI and leads to improvements in training load and assisted standing. Additional assessments will be incorporated to further identify improvements in function and quality of life. Future work will assess the benefits of using epidural spinal cord stimulation combined with A&L cycling after motor complete SCI.

Immediate Effects of Anti-Spastic Epidural Cervical Spinal Cord Stimulation on Functional Connectivity of the Central Motor System in Patients with Stroke- and Traumatic Brain Injury-Induced Spasticity: A Pilot Resting-State Functional Magnetic Resonance Imaging Study.

Spinal cord stimulation (SCS) is one approach to the potential improvement of patients with post-stroke or post-traumatic spasticity. However, little is known about whether and how such interventions alter supraspinal neural systems involved in the pathogenesis of spasticity. This pilot study investigated whether epidural spinal cord stimulation at the level of the C3-C5 cervical segments, aimed at reducing spasticity, alters the patterns of functional connectivity of the brain. Eight patients with spasticity in the right limbs as a result of left cerebral hemisphere damage (due to hemorrhagic and ischemic stroke or traumatic and anoxic brain injury) were assessed with fMRI immediately before and immediately after short-term (1 to 6 days) test cervical epidural SCS therapy. Eight demographically and clinically comparable patients with spasticity in the right extremities due to a left hemisphere ischemic stroke and brain injury who received conventional therapy were examined as a control group. All patients also had paresis of one or two limbs and hyperreflexia. After the SCS therapy, there were three main findings: (1) higher functional connectivity of the brainstem to the right premotor cortex and changes in functional connectivity between cortical motor areas, (2) increased functional connectivity between the right and left lateral nodes of the sensorimotor network, and (3) a positive correlation between decreased spasticity in the right leg and increased functional connectivity within the right hemisphere sensorimotor cortex. All these changes in functional connectivity occurred with a statistically significant decrease in spasticity, as assessed using the modified Ashworth scale. The control group showed no decrease in spasticity or increase in functional connectivity in any of the seeds of interest. On the contrary, a decrease in functional connectivity of the brainstem and right postcentral gyrus was observed in this group during the observation period. We were thus able to detect intrinsic brain connectivity rearrangements that occurred during spasticity mitigation following short epidural SCS therapy. The clinical results obtained confirmed the efficacy of short-term anti-spastic SCS therapy. The obtained data on functional rearrangements of the central motor system may shed light on the mechanism of antispastic action of this procedure.

Spinal cord stimulation for spinal cord injury – Where do we stand? A narrative review

Recovery of function following a complete spinal cord injury (SCI) or an incomplete SCI where recovery has plateaued still eludes us despite extensive research. Epidural spinal cord stimulation (SCS) was initially used for managing neuropathic pain. It has subsequently demonstrated improvement in motor function in otherwise non-recovering chronic spinal cord injury in animal and human trials. The mechanisms of how it is precisely effective in doing so will need further research, which would help refine the technology for broader application. Transcutaneous spinal cord stimulation (TSCS) is also emerging as a modality to improve the functional outcome in SCI individuals, especially when coupled with appropriate rehabilitation. Apart from motor recovery, ESCS and TSCS have also shown improvement in autonomic, metabolic, genitourinary, and pulmonary function. Since the literature on this is still in its infancy, with no large-scale randomised trials and different studies using different protocols in a wide range of patients, a review of the present literature is imperative to better understand the latest developments in this field. This article examines the existing literature on the use of SCS for SCI individuals with the purpose of enabling functional recovery. It also examines the voids in the present research, thus providing future directions.

Mid-lumbar (L3) epidural stimulation effects on bladder and external urethral sphincter in non-injured and chronically transected urethane-anesthetized rats

Recent pre-clinical and clinical spinal cord epidural stimulation (scES) experiments specifically targeting the thoracolumbar and lumbosacral circuitries mediating lower urinary tract (LUT) function have shown improvements in storage, detrusor pressure, and emptying. With the existence of a lumbar spinal coordinating center in rats that is involved with external urethral sphincter (EUS) functionality during micturition, the mid-lumbar spinal cord (specifically L3) was targeted in the current study with scES to determine if the EUS and thus the void pattern could be modulated, using both intact and chronic complete spinal cord injured female rats under urethane anesthesia. L3 scES at select frequencies and intensities of stimulation produced a reduction in void volumes and EUS burst duration in intact rats. After chronic transection, three different subgroups of LUT dysfunction were identified and the response to L3 scES promoted different cystometry outcomes, including changes in EUS bursting. The current findings suggest that scES at the L3 level can generate functional neuromodulation of both the urinary bladder and the EUS in intact and SCI rats to enhance voiding in a variety of clinical scenarios.

ID: 214352 Microdissection of the Swine Spinal Cord to Reveal Lumbar and Thoracic Rootlets

Spinal cord epidural stimulation (SCS) is a safe and effective therapy of chronic pain. The most common complication for SCS is lead migration, resulting in inefficient stimulation. In addition, the shunting of current or activation of the dorsal rootlets may result in contraction of back muscles, via activation of motor fibers recruited at lower stimulation amplitudes. Activation of these rootlets could cause electromyography (EMG) bleed-through into the evoked compound action potential (ECAPs) recordings, as well as cause side effect during SCS therapy. In some cases, motor activation may limit the range of stimulation to levels below what is required for pain therapy.

ID: 221565 EEG Signatures of Epidural Spinal Cord Stimulation: A Dosing and Mechanism of Action Study

The neurophysiological process by which epidural spinal cord stimulation (SCS) relieves pain and the relationship of paresthesia perception to analgesia are still poorly understood. While the gate control theory of pain processing[1] suggests that SCS-induced sensory paresthesia interferes with ascending pain processing, a wealth of evidence contradicts this notion.[2] Studies indicate that SCS may produce analgesia at sub-paresthesia amplitudes by modulating key brain circuits[3] despite similar effects at spinal levels.[4] To date, there are limited human studies evaluating the effect of SCS on chronic pain states and endogenous neural patterns as measured by electroencephalography (EEG).