Spinal Cord Stimulation Electrode Research Articles

Anatomical-related factors and outcome of percutaneous short-term spinal cord stimulation electrode shift in patients with disorders of consciousness: a retrospective study

BackgroundDisorders of consciousness (DoC) represent a spectrum of neurological conditions that pose significant treatment challenges. Percutaneous short-term spinal cord stimulation (SCS) has emerged as a promising experimental diagnostic treatment to assess and potentially improve consciousness levels. However, the effectiveness of this intervention is frequently compromised by the shift of electrodes, particularly in the cervical region, which can negatively affect therapeutic outcomes.MethodsThis retrospective study aimed to study if electrodes shift in percutaneous short-term SCS in patients with DoC would affect the outcome. We analyzed the relationship between electrode shift length and patient outcome, as well as the correlation with various anatomical parameters, including the actual length of the cervical spine, linear length, spinal canal transverse diameter, spinal canal diameter, and C2 cone height, in a cohort of patients undergoing the procedure.ResultsOur findings revealed that in patients with better outcome, there are significant less patient with electrode shift (p = 0.019). Further, a linear correlation was found between the length of electrode shift and patients’ outcome (Rho = 0.583, p = 0.002), with longer shift lengths associated with poorer outcomes. Contrary to our expectations, there was no significant association between the measured anatomical parameters and the extent of electrode shift. However, a trend was found between the actual length of the cervical spine and the shift of the electrode (p = 0.098). Notably, the shorter spinal canal transverse diameter was found to be significantly associated with better outcome in patients with DoC receiving percutaneous short-term SCS (p = 0.033).ConclusionThese results highlight the clinical importance of electrode stability in the cervical region during SCS treatment for patients with DoC. Ensuring secure placement of electrodes may play a crucial role in enhancing patients’ outcome and minimize postoperative complications. Given the lack of association with expected anatomical parameters, future research should investigate other factors that could impact electrode stability to optimize this therapeutic intervention.

894 Comparison of Intraoperative Neural Changes During Tonic Versus High-Frequency Spinal Cord Stimulation in Chronic Pain Patients

INTRODUCTION: Chronic pain is a prevalent issue that may affect up to 34% of US adults, and spinal cord stimulation (SCS) is a promising therapy. However, SCS device selection remains a challenge because there are currently no objective biomarkers to evaluate chronic pain, or to predict which patients will be responders. METHODS: Intraoperative EEG signals were recorded in 24 chronic pain patients (14 women) during permanent SCS electrode placement surgery. Neural responses were captured with respect to tonic (60 Hz/300 µs) and high-frequency (1 kHz/30 µs) SCS paradigms in a randomized manner and correlated to Numeric Rating Scale (NRS) scores. All data were analyzed offline in MATLAB and SPSS v28.0.1.1. RESULTS: Our analyses for the main effects demonstrated a significant difference between cortical regions (F(2.88,57.7) = 7.60 , p < 0.001) and a marginal difference between stimulation conditions (F(2,40) = 2.970, p = 0.063). The post hoc analysis for these factors revealed that alpha/theta peak power ratio was significantly different between in central regions (C3-C4) between tonic and HF stimulation (p = 0.006) and temporal regions (T3-T4) between baseline and HF stimulation (p = 0.049). The comparison of NRS scores before and 3 months after surgery indicated a significant improvement in pain intensity (p < 0.001) at the group level. The neural features found to be significantly correlated with preoperative NRS scores in PFC (p = 0.036 and p = 0.025) and temporal regions (p = 0.041 and p = 0.012) under both stimulations. CONCLUSIONS: Our preliminary results support the possibility that different stimulation patterns affect the electrophysiological activity differently in various cortical regions. Such differences might account for the variability in pain suppression in patients with chronic pain treated with SCS. Future work will utilize this dataset to develop a machine learning classifier to support objective device selection strategies.

ExoNav: A Novel Robotic Steering and Latching Mechanism for Spinal Cord Stimulation Electrodes

ExoNav: A Novel Robotic Steering and Latching Mechanism for Spinal Cord Stimulation Electrodes

The impact of spinal cord stimulation on a chronic model of atrial fibrillation in a mini-pig experiment

Introduction: Despite the advancement interventional methods for treating atrial fibrillation, the effectiveness of catheter ablation remains poor, especially in patients with persistent and long-persistent atrial fibrillation. Thus, experts continue to explore new treatments for this arrhythmia. The issue of experimental studies investigating the association between spinal cord stimulation and atrial fibrillation is mainly attributed to the lack of optimal algorithms for spinal cord stimulation in animal experiments. Therefore, it is important to develop adequate algorithms for spinal cord stimulation in the chronic model of atrial fibrillation.Objective: To evaluate the impact of spinal cord stimulation on the model of atrial fibrillation in mini-pigs.Methods: In a series of experiments, 6 (100%) successful implantations of electrodes and pacemakers, and spinal cord stimulation electrodes were performed. The electrodes were used to stimulate the atria, creating a model of atrial fibrillation, while the spinal cord stimulation was carried out using an electrode implanted into the spinal canal. During the experiment, an electrophysiological study was performed using an implanted pacemaker. The inducibility of atrial fibrillation was assessed before and after the experiment using various spinal cord stimulation algorithms.Results: There were no complications associated with surgery or stimulation of the atria and spinal cord. Spinal stimulation had a modeling effect on the autonomic nervous system, significantly changing the average heart rate, Wenckebach point, and effective refractory period. When comparing spinal stimulation algorithms, algorithm 1 was found to significantly reduce the atrial fibrillation inducibility.Conclusion: Spinal cord stimulation had a modeling effect on the autonomic nervous system, significantly changing the average heart rate, Wenckebach point, and effective refractory period. Inducibility of atrial fibrillation decreases with changes in the spinal pacing algorithm. Received 15 September 2023. Revised 30 October 2023. Accepted 31 October 2023. Funding: The study was supported by Russian Science Foundation (project No. 22-25-00672). Conflict of interest: The authors declare no conflict of interest. Contribution of the authorsConception and study design: A.G. Filippenko, V.V. Shabanov, V.I. MurtazinData collection and analysis: A.G. Filippenko, T.U. Khalkhoghaev, V.V. BeloborodovStatistical analysis: A.G. Filippenko, V.V. ShabanovDrafting the article: A.G. Filippenko, V.V. BeloborodovCritical revision of the article: V.V. ShabanovFinal approval of the version to be published: V.V. Shabanov, A.G. Filippenko, V.V. Beloborodov, T.U. Khalkhoghaev, V.I. Murtazin

Defining the Boundaries of Patient Perception in Spinal Cord Stimulation Programming

ObjectivesRecent developments in spinal cord stimulation (SCS) programming have initiated new modalities of imperceptible stimulation. However, the boundaries of sensory perception are not well defined. The BEnchtop NEuromodulation Following endIng of Trial study aimed to create a map of perceptual threshold responses across a broad range of SCS parameters and programming to inform subperception therapy design. Materials and MethodsThis multicenter study was conducted at seven US sites. A total of 43 patients with low back and/or leg pain who completed a percutaneous commercial SCS trial were enrolled. Test stimulation was delivered through trial leads for approximately 90 minutes before removal. SCS parameters, including amplitude, frequency, pulse width (PW), electrode configuration, cycling, and multifrequency stimulation were varied during testing. Paresthesia threshold (PT), comfort level (CL), perceptual coverage area, and paresthesia quality (through patient selection of keywords) were collected. Differences were evaluated with analysis of variance followed by post hoc multiple comparisons using t-tests with Bonferroni correction. ResultsPT was primarily determined by PW and was insensitive to frequency for constant frequency stimulation (range: 20 Hz–10 kHz; F(1284) = 69.58, p < 0.0001). For all tests, CL was approximately 25% higher than PT. The dominant variable that influenced paresthesia quality was frequency. Sensations described as comfortable and tingling were most common for frequencies between 60 Hz and 2.4 kHz; unpleasant sensations were generally more common outside this range. Increasing distance between active electrodes from 7 mm to 14 mm, or cycling the SCS waveform at 1 Hz, decreased PT (p < 0.0001). Finally, PT for a low-frequency stimulus (ie, 60 Hz) was unaffected by mixing with a sub-PT high-frequency stimulus. ConclusionsIn contrast to previous work investigating narrower ranges, PW primarily influenced PT, independently of frequency. Paresthesia quality was primarily influenced by pulse frequency. These findings advance our understanding of SCS therapy and may be used to improve future novel neuromodulation paradigms.

Is it possible to generate an additional pleasant and pain-relieving muscle stimulation when using a low-frequency spinal cord stimulation (SCS) for the treatment of lower back pain? Pilot study: A new technique: "MuscleSCS".

The combined use of spinal cord stimulation (SCS) and muscle stimulation, in the treatment of chronic pain, using the same probe, could improve the clinical results. However, this technique has not been established as yet. It was our hypothesis that it is possible to generate muscle stimulation by using low frequencies with SCS electrodes and use it to additionally treat chronic back pain. We generated muscle stimulation in patients with previously implanted SCS electrodes, for the treatment of lower back pain, by using low frequencies (2, 4, 6, and 8 Hz) and different contact combinations of the electrodes. The results were evaluated by using visual inspection (videos), haptic control, surface electromyography (EMG), and sonographic recordings. This pilot study (17 patients, seven females, age 36-87 years, 11 percutaneous paddle leads, and 6 octrodes) was performed at the Neurosurgical Department of the University of Tuebingen. The most preferred frequencies were 6 Hz (45.5% of percutaneous paddle leads) and 8 Hz (50% of octrodes) at contacts 3&4 or 5&6. The preference of frequencies differed significantly among genders (p = 0.023). Simultaneous EMG and ultrasonic recordings demonstrated the generation of muscle potentials and the stimulation of deeper muscle groups. In this study, it has been shown that with low-frequency SCS stimulation, pleasant and pain-relieving muscle contractions of the lower and upper back can also be generated. This combined method has been coined by us as "MuscleSCS" technique. Clinical trials are necessary to establish the value of this combined technique and its subtypes.

An optimization framework for targeted spinal cord stimulation

Objective. Spinal cord stimulation (SCS) is a common neurostimulation therapy to manage chronic pain. Technological advances have produced new neurostimulation systems with expanded capabilities in an attempt to improve the clinical outcomes associated with SCS. However, these expanded capabilities have dramatically increased the number of possible stimulation parameters and made it intractable to efficiently explore this large parameter space within the context of standard clinical programming procedures. Therefore, in this study, we developed an optimization approach to define the optimal current amplitudes or fractions across individual contacts in an SCS electrode array(s). Approach. We developed an analytic method using the Lagrange multiplier method along with smoothing approximations. To test our optimization framework, we used a hybrid computational modeling approach that consisted of a finite element method model and multi-compartment models of axons and cells within the spinal cord. Moreover, we extended our approach to multi-objective optimization to explore the trade-off between activating regions of interest (ROIs) and regions of avoidance (ROAs). Main results. For simple ROIs, our framework suggested optimized configurations that resembled simple bipolar configurations. However, when we considered multi-objective optimization, our framework suggested nontrivial stimulation configurations that could be selected from Pareto fronts to target multiple ROIs or avoid ROAs. Significance. We developed an optimization framework for targeted SCS. Our method is analytic, which allows for the fast calculation of optimal solutions. For the first time, we provided a multi-objective approach for selective SCS. Through this approach, we were able to show that novel configurations can provide neural recruitment profiles that are not possible with conventional stimulation configurations (e.g. bipolar stimulation). Most importantly, once integrated with computational models that account for sources of interpatient variability (e.g. anatomy, electrode placement), our optimization framework can be utilized to provide stimulation settings tailored to the needs of individual patients.

Evoked compound action potentials during spinal cord stimulation: effects of posture and pulse width on signal features and neural activation within the spinal cord

Objective. Evoked compound action potential (ECAP) recordings have emerged as a quantitative measure of the neural response during spinal cord stimulation (SCS) to treat pain. However, utilization of ECAP recordings to optimize stimulation efficacy requires an understanding of the factors influencing these recordings and their relationship to the underlying neural activation. Approach. We acquired a library of ECAP recordings from 56 patients over a wide assortment of postures and stimulation parameters, and then processed these signals to quantify several aspects of these recordings (e.g., ECAP threshold (ET), amplitude, latency, growth rate). We compared our experimental findings against a computational model that examined the effect of variable distances between the spinal cord and the SCS electrodes. Main results. Postural shifts strongly influenced the experimental ECAP recordings, with a 65.7% lower ET and 178.5% higher growth rate when supine versus seated. The computational model exhibited similar trends, with a 71.9% lower ET and 231.5% higher growth rate for a 2.0 mm cerebrospinal fluid (CSF) layer (representing a supine posture) versus a 4.4 mm CSF layer (representing a prone posture). Furthermore, the computational model demonstrated that constant ECAP amplitudes may not equate to a constant degree of neural activation. Significance. These results demonstrate large variability across all ECAP metrics and the inability of a constant ECAP amplitude to provide constant neural activation. These results are critical to improve the delivery, efficacy, and robustness of clinical SCS technologies utilizing these ECAP recordings to provide closed-loop stimulation.

Related Factors and Outcome of Spinal Cord Stimulation Electrode Deviation in Disorders of Consciousness.

Background and PurposeSpinal cord stimulation (SCS) has been reported to be a promising neuromodulation method for patients with disorders of consciousness (DOC). Our previous studies found that clinical characteristics of patients and SCS stimulation parameters could affect the therapeutic effects of SCS, while surgical-related factors remain unknown. Through the improvement of surgical procedures, most of the SCS electrodes are implanted in the middle, while a small number of electrodes have still deviated.MethodsA total of 137 patients received SCS treatment in our institutions from 1 January 2010 to 31 December 2020. Among them, 27 patients were found with electrode deviation and met the inclusion criteria. Patients were grouped according to whether the electrode deviation angle (EDA) is >30°, respectively. Clinical characteristics of patients and SCS stimulation parameters were compared. Potential related factors and outcomes were evaluated by Chi-square test or two-way repeated measures analysis.ResultsTwenty seven patients receiving cervical SCS treatment were found to have electrode deviation postoperatively. Among them, 12 patients were classified into the more deviation group. No significant difference was found among age, sex, pathogeny, course of DOC, C2–C5 distance, spinal cord to spinal canal ratio at C2 level, and preoperative JFK Coma Recovery Scale-Revised (CRS-R) scores. We found that the electrode direction significantly deviated to the contralateral side in the lateral decubitus position (P = 0.025). The maximum tolerant stimulation intensity in the less deviation group (1.70 ± 0.41) was significantly higher than that in the more deviation group (1.25 ± 0.34) (P = 0.006). Under the strongest stimulation, less unilateral limb tremor (P = 0.049) and paroxysmal sympathetic hyperactivity (PSH) episodes (P = 0.030) were found. EDA had a significant effect on postoperative CRS-R in patients, and patients in the less deviation group had significantly higher postoperative CRS-R (P < 0.01). There was also an interaction effect between EDA and postoperative time. With the prolonged postoperative time, the CRS-R improvement rate of patients with different EDA was different, and the CRS-R improved faster in patients with less EDA (P < 0.05).ConclusionsElectrode deviation will affect the outcome of patients receiving cervical SCS treatment. The intraoperative surgical position is associated with postoperative electrode deviation direction. The reduction of EDA under 30° can increase maximum tolerant stimulation intensity, reduce complications, and further improve patients' outcomes.

HPR66 Cost Savings Associated with One-Stage vs Two-Stage Spinal Cord Stimulation from Medicare Perspective

Spinal cord stimulation (SCS) is an FDA approved therapy for failed back surgery syndrome. In clinical practice typically patients undergo a trial phase, in which temporary electrodes are implanted in the patients. Only those patients who experience adequate pain relief progress to the next step where the SCS electrodes and the pulse generator device are permanently implanted (trial success rate). Centers for Medicare & Medicaid Services (CMS) policy mandates this two-stage process for reimbursement eligibility.

Tonic, Burst, and Burst-Cycle Spinal Cord Stimulation Lead to Differential Brain Activation Patterns as Detected by Functional Magnetic Resonance Imaging

ObjectiveThe objective of this preclinical study was to examine the responses of the brain to noxious stimulation in the presence and absence of different modes of spinal cord stimulation (SCS) using blood-oxygen-level-dependent functional magnetic resonance imaging (BOLD-fMRI). Materials and MethodsSprague-Dawley rats were randomized to groups based on the mode of SCS delivered which included tonic stimulation (n = 27), burst stimulation (n = 30), and burst-cycle stimulation (n = 29). The control (sham) group (n = 28) received no SCS. The SCS electrode was inserted between T10 and T12 spinal levels prior to fMRI session. The experimental protocol for fMRI acquisition consisted of an initial noxious stimulation phase, a treatment phase wherein the SCS was turned on concurrently with noxious stimulation, and a residual effect phase wherein the noxious stimulation alone was turned on. The responses were statistically analyzed through paired t-test and the results were presented as z-scores for the quantitative analysis of the fMRI data. ResultsThe treatment with different SCS modes attenuated the BOLD brain responses to noxious hindlimb stimulation. The tonic, burst, and burst-cycle SCS treatment attenuated BOLD responses in the caudate putamen (CPu), insula (In), and secondary somatosensory cortex (S2). There was little to no corresponding change in sham control in these three regions. The burst and burst-cycle SCS demonstrated greater attenuation of BOLD signals in CPu, In, and S2 compared to tonic stimulation. ConclusionThe high-resolution fMRI study using a rat model demonstrated the potential of different SCS modes to act on several pain-matrix-related regions of the brain in response to noxious stimulation. The burst and burst-cycle SCS exhibited greater brain activity reduction in response to noxious hindlimb stimulation in the caudate putamen, insula, and secondary somatosensory cortex compared to tonic stimulation.

Conscious Sedation Using Dexmedetomidine During Surgical Paddle Lead Placement Improves Outcome in Spinal Cord Stimulation: A Case Series of 25 Consecutive Patients

Different anesthesia techniques are used for surgical implantation of paddle lead electrodes for neurostimulation through a laminectomy. We wanted to evaluate the use of dexmedetomidine as sedative for this procedure in a series of patients. Second, we wanted to verify whether the stimulation pattern and position of the electrode had to be changed during the procedure guided by the patient's feedback. Twenty-five consecutive patients received surgical implantation of a spinal cord stimulation electrode under conscious sedation using dexmedetomidine and local anesthesia. We evaluated the effects of the administered drug, the patient comfort, and the adequacy of the stimulation pattern. Twenty-four patients completed the procedure with only dexmedetomidine and local anesthetic. Infusion was started on average 55 minutes (sd 29) prior to incision. The mean dose of lidocaine was 430 mg (sd 95). There were no significant hemodynamic changes. Median time to reach Modified Aldrete's score postoperative was 67 minutes (sd 38). In 46% of the patients, the position of the electrode was changed guided by the feedback of the patient. More than half of the patients remember most details of the procedure. Only four patients mentioned substantial discomfort and only three would definitely not want to undergo this procedure again. Implantation of spinal cord stimulation electrodes through a surgical laminectomy using dexmedetomidine is a safe and feasible procedure with adequate comfort for patient and surgeon. This way of working increases the optimal position of the electrode resulting in the most convenient stimulation pattern and avoiding revisions.

Rapid Visualization Tool for Intraoperative Dorsal Column Mapping Triggered by Spinal Cord Stimulation in Chronic Pain Patients.

Spinal cord stimulation (SCS) is a widely accepted effective treatment for managing chronic pain. SCS outcomes depend highly on accurate placement of SCS electrodes at the appropriate spine level for a desired pain relief. Intraoperative neurophysiological monitoring (IONM) under general anesthesia provides an objective real-time mapping of the dorsal columns, and has been shown to be a safe and effective tool. IONM applies stimulation to multiple electrode contacts at various intensities and monitors the triggered electromyography (EMG) responses in several muscle groups simultaneously. Therefore, it requires dynamic communication between neurosurgeon and neurophysiologist and continuous real-time annotations of the responses, which makes the procedure complex and experience-based. Here, we describe an automated data visualization tool that generates patient specific activity maps using intraoperatively collected signals. Responses were collected using a High-resolution (HR)-SCS lead with 8 columns of electrodes spanning the dorsal columns. Our JavaScript/Python based graphical user interface (GUI) provides a fast and robust visualization of EMG activity via denoising, feature extraction, normalization, and overlaying of the activity maps on body images in selected colormaps. In contrast to reviewing series of EMG signals, our user-friendly tool provides a rapid and robust analysis of stimulation effects on various muscle groups and direct comparison across subjects and/or stimulation settings. Future work includes expanding analytics capabilities and operating room implementation as a real-time processing tool that can be used in conjunction with the current IONM techniques.

Magnetically Guided Catheters, Micro- and Nanorobots for Spinal Cord Stimulation.

Spinal cord stimulation (SCS) is an established treatment for refractory pain syndromes and has recently been applied to improve locomotion. Several technical challenges are faced by surgeons during SCS lead implantation, particularly in the confined dorsal epidural spaces in patients with spinal degenerative disease, scarring and while targeting challenging structures such as the dorsal root ganglion. Magnetic navigation systems (MNS) represent a novel technology that uses externally placed magnets to precisely steer tethered and untethered devices. This innovation offers several benefits for SCS electrode placement, including enhanced navigation control during tip placement, and the ability to position and reposition the lead in an outpatient setting. Here, we describe the challenges of SCS implant surgery and how MNS can be used to overcome these hurdles. In addition to tethered electrode steering, we discuss the navigation of untethered micro- and nanorobots for wireless and remote neuromodulation. The use of these small-scale devices can potentially change the current standard of practice by omitting the need for electrode and pulse generator implantation or replacement. Open questions include whether small-scale robots can generate an electrical field sufficient to activate neuronal tissue, as well as testing precise navigation, placement, anchoring, and biodegradation of micro- and nanorobots in the in vivo environment.

MP08-15 HIGH-RESOLUTION EPIDURAL SPINAL CORD STIMULATION (HR-SCS) EVOKES SELECTIVE MICTURITION AND CONTINENCE REFLEXES THROUGH A FREQUENCY-DEPENDENT EFFECT GOVERNED BY DISTINCT NEURAL CIRCUITS

You have accessJournal of UrologyBladder & Urethra: Anatomy, Physiology & Pharmacology (MP08)1 Sep 2021MP08-15 HIGH-RESOLUTION EPIDURAL SPINAL CORD STIMULATION (HR-SCS) EVOKES SELECTIVE MICTURITION AND CONTINENCE REFLEXES THROUGH A FREQUENCY-DEPENDENT EFFECT GOVERNED BY DISTINCT NEURAL CIRCUITS Chaitanya Gopinath, Maria K. Jantz, Ritesh Kumar, Bryan L. McLaughlin, and Robert A. Gaunt Chaitanya GopinathChaitanya Gopinath More articles by this author , Maria K. JantzMaria K. Jantz More articles by this author , Ritesh KumarRitesh Kumar More articles by this author , Bryan L. McLaughlinBryan L. McLaughlin More articles by this author , and Robert A. GauntRobert A. Gaunt More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000001981.15AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Spinal cord stimulation (SCS) has been explored for controlling lower urinary tract function in experimental and clinical settings. However, there are no mechanistic and reproducible approaches to evoke both micturition and continence reflexes. Here, we demonstrate that epidural SCS can selectively evoke micturition and continence behaviors in both isovolumetric and cystometric studies in feline anesthetized animal model. Our results indicate the existence of two distinct frequency-dependent neural circuits mediating continence and micturition evoked by varying stimulus frequencies. METHODS: Three male and three female cats (n=6) were anesthetized with α-chloralose after initial surgical preparations under isoflurane anesthesia. Nerve cuffs were placed unilaterally on the pelvic nerve, pudendal nerve and its branches (sensory, deep perineal and caudal rectal nerves). HR-SCS electrodes (Ripple Neuro, Micro-Leads Medical) were placed on the epidural surface of sacral cord and cauda equina. Stimulation pulse trains with amplitudes between 200-800 µA were delivered through SCS electrodes while recording bladder pressure and compound action potentials in the peripheral nerve cuffs. Electromyograms from the pelvic floor and urethral sphincter, as well as bladder pressure data were collected, first under isovolumetric bladder conditions and later during filling cystometries. RESULTS: Epidural SCS through many electrodes was able to elicit functional changes in the bladder and urethra. We also identified bipolar electrode pairs that evoked a frequency-dependent effect. Stimulation at 3 Hz stimulation evoked a continence reflex, while the same electrodes evoked a voiding reflex when the stimulation frequency was changed to 33 Hz. Inhibition through 3 Hz stimulation was particularly robust and resulted in abolishing all non-voiding contractions (NVCs) and decreasing the bladder pressure to its baseline value. Voiding under 33 Hz was incomplete and varied between 20-50% of the infused volume. In 3 animals, an acute spinalization at T10 abolished all 33 Hz-evoked responses suggesting that this neural circuit requires an intact spino-bulbo-spinal reflex. The 3 Hz continence reflex remained unaffected by spinalization suggesting a local reflex in the lumbosacral spinal cord. CONCLUSIONS: HR-SCS can selectively evoke continence and micturition reflexes through a unique frequency-dependent effect. Source of Funding: NIH OT2OD024908 and Craig H. Neilsen Foundation—476681 © 2021 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 206Issue Supplement 3September 2021Page: e155-e156 Advertisement Copyright & Permissions© 2021 by American Urological Association Education and Research, Inc.MetricsAuthor Information Chaitanya Gopinath More articles by this author Maria K. Jantz More articles by this author Ritesh Kumar More articles by this author Bryan L. McLaughlin More articles by this author Robert A. Gaunt More articles by this author Expand All Advertisement Loading ...

1-kHz high-frequency spinal cord stimulation alleviates chronic refractory pain after spinal cord injury: a case report

BackgroundPatients with spinal cord injury (SCI) frequently complain of intractable pain that is resistant to conservative treatments. Here, we report the successful application of 1-kHz high-frequency spinal cord stimulation (SCS) in a patient with refractory neuropathic pain secondary to SCI.Case presentationA 69-year-old male diagnosed with SCI (C4 American Spinal Injury Association Impairment Scale A) presented with severe at-level bilateral upper extremity neuropathic pain. Temporary improvement in his symptoms with a nerve block implied peripheral component involvement. The patient received SCS, and though the tip of the leads could not reach the cervical vertebrae, a 1-kHz frequency stimulus relieved the intractable pain.ConclusionsSCI-related symptoms may include peripheral components; SCS may have a considerable effect on intractable pain. Even when the SCS electrode lead cannot be positioned in the target area, 1-kHz high-frequency SCS may still produce positive effects.

A Retrospective Database Review of the Indications, Complications, and Incidence of Subsequent Spine Surgery in 12,297 Spinal Cord Stimulator Patients

Retrospective review. To analyze the indications, incidence of minor and major complications, and rate of subsequent spinal surgery or revision after spinal cord stimulator (SCS) placement for degenerative spine disease. Despite the application of SCS in various chronic pain conditions, there remains a growing debate on the efficacy and necessity of SCS in degenerative spine disease. A nationally representative sample of Medicare patients who had an open (via laminectomy) SCS placement for degenerative spine disease between 2005 and 2014 were studied. Indications, complications, and the rate of subsequent spinal surgery within 90 days, one year, two years, and three years postoperatively were studied using Current Procedural Terminology (CPT) and International Classification of Diseases (ICD) codes. We included 12,297 SCS patients in our study cohort. The most common indications for SCS placement were postlaminectomy syndrome (25.2%) and chronic pain syndrome (20.2%). There was a 4.2 and 17.2% incidence of postoperative back or spine emergency department (ED) visits, and a 0.3 and 3.4% incidence of SCS electrode removal or reimplantation within 90 days and 1 year, respectively. Other reported surgical complications were wound infection (4.3%), hematoma (0.5%), and seroma (0.4%) at one year postoperatively. Within 90 days after SCS implantation, the rate of subsequent spine surgery or revision was 0.9%. This incidence was 7.1, 11.7, and 15.5% at one, two, and three years, respectively. In our retrospective analysis of Medicare patients, the most common indication for SCS implantation was postlaminectomy syndrome. Common postoperative complications included wound infection, and removal of SCS electrodes at one year postoperatively. About 17% patients had an ED visit for spine-related symptoms within one year of device implantation, and 15.5% underwent subsequent spinal decompression and/or fusion within 3 years after primary SCS placement.

Anatomical and technical factors affecting the neural response to epidural spinal cord stimulation

Objective. Spinal cord stimulation (SCS) is a common neurostimulation therapy to treat chronic pain. Computational models represent a valuable tool to study the potential mechanisms of action of SCS and to optimize the design and implementation of SCS technologies. However, it is imperative that these computational models include the appropriate level of detail to accurately predict the neural response to SCS and to correlate model predictions with clinical outcomes. Therefore, the goal of this study was to investigate several anatomic and technical factors that may affect model-based predictions of neural activation during thoracic SCS. Approach. We developed computational models that consisted of detailed finite element models of the lower thoracic spinal cord, surrounding tissues, and implanted SCS electrode arrays. We positioned multicompartment models of sensory axons within the spinal cord to calculate the activation threshold for each sensory axon. We then investigated how activation thresholds changed as a function of several anatomical variables (e.g. spine geometry, dorsal rootlet anatomy), stimulation type (i.e. voltage-controlled vs. current-controlled), electrode impedance, lead position, lead type, and electrical properties of surrounding tissues (e.g. dura conductivity, frequency-dependent conductivity). Main results. Several anatomic and modeling factors produced significant percent differences or errors in activation thresholds. Rostrocaudal positioning of the cathode with respect to the vertebrae had a large effect (up to 32%) on activation thresholds. Variability in electrode impedance produced significant changes in activation thresholds for voltage-controlled stimulation (38% to 51%), but had little effect on activation thresholds for current-controlled stimulation (less than 13%). Changing the dura conductivity also produced significant differences in activation thresholds. Significance. This study demonstrates several anatomic and technical factors that can affect the neural response to SCS. These factors should be considered in clinical implementation and in future computational modeling studies of thoracic SCS.

Lower limb ischemia cured by stimulation electrode implantation assisted with microendoscopic discectomy system: A case report

A 58-year-old male patient diagnosed with thromboangiitis obliterans (Fontaine stage IV) was recently treated with microendoscope discectomy system-assisted spinal cord stimulation electrode implantation and cured by department of vascular surgery combined with department of spinal surgery at Peking University People's Hospital. The patient suffered from cold injury to the right foot 14 years ago, which was cold, painful, numb, and then the toe was ulcerated and gangrene. Only the right foot small toe was left. The right foot skin was swollen from the toe to the proximal segment 1 year ago, accompanied by resting pain. Both pain and autologous bone marrow stem cell transplantation were ineffective. The above symptoms were aggravated three months ago, and the pain was severe. The visual analogue score was 10 points. A high amputation of the left lower extremity was performed 30 years ago due to trauma. Physical examination: the bilateral femoral artery was weak, and the right radial artery, posterior tibial artery, and dorsal artery were not touched. Buerger sign (+). Auxiliary examination: angiography of both lower extremities showed complete occlusion of the bilateral external iliac artery and its distal end. The percutaneous oxygen partial pressure was measured to be 30 mmHg on the right side of the iliac crest. The operation was performed under the local anesthesia. After X-ray positioning, the body projection of the lumbar vertebrae 1-2 lamina gap was marked. The skin had a 1.8 cm incision on the caudal side 2 cm from the mark. Then the dilators were used, and the working sleeve was tilted to the lumbar vertebrae 1-2 lamina gap. The microendoscope discectomy system was installed, the electrode was directly placed into the epidural space from the interlamina space under the microendoscope, the vascular surgeon adjusted the position of the electrode in the spinal canal under fluoroscopy, then connected the stimulator, adjusted the current until the patient had the lower limb fever, fixed electrode position, removed the microendoscope discectomy system after hemostasis under the microendoscope, used the guide needle to lead the electrode through the lumbar subcutaneous and then sutured the incision. After the operation, the electrode was connected to the temporary stimulator to stimulate for several minutes, the patient felt numbness in his lower limbs. In less than one hour, the skin temperature of the affected limb increased, and the painkiller could be stopped while sleeping. After 1 week, the skin temperature of the affected limb increased, and the percutaneous oxygen partial pressure of the foot and ankle was 36 mmHg, and the pain improved, and the score was reduced to 2 points. One month after surgery, the patient underwent permanent stimulator implantation. The pain disappeared after 3 months and half year of follow-up, and the score was reduced to 1 point. Microendoscope discectomy system-assisted spinal cord stimulation electrode implantation can complete the operation quickly, safely and effectively, and greatly reduce the number of intraoperative fluoroscopy and reduce the occurrence of complications.

Active Recharge Burst and Tonic Spinal Cord Stimulation Engage Different Supraspinal Mechanisms: A Functional Magnetic Resonance Imaging Study in Peripherally Injured Chronic Neuropathic Rats.

To assess the supraspinal working mechanisms of the burst spinal cord stimulation (SCS) mode, we used functional magnetic resonance imaging (fMRI) in chronic neuropathic rats. We hypothesized that active recharge burst SCS would induce a more profound blood oxygenation level-dependent (BOLD) signal increase in areas associated with cognitive-emotional aspects of pain, as compared to tonic SCS. Sprague Dawley rats (n=17) underwent a unilateral partial sciatic nerve ligation, which resulted in chronic neuropathic pain. Quadripolar SCS electrodes were epidurally positioned on top of the dorsal columns at Th13. Isoflurane-anesthetized (1.5%) rats received either tonic SCS (n=8) or burst SCS (n=9) at 66% of motor threshold. BOLD fMRI was conducted before, during, and after SCS using a 9.4-T horizontal bore scanner. Overall, both tonic and burst SCS induced a significant increase of BOLD signal levels in areas associated with the location and intensity of pain, and areas associated with cognitive-emotional aspects of pain. Additionally, burst SCS significantly increased BOLD signal levels in the raphe nuclei, nucleus accumbens, and caudate putamen. Tonic SCS did not induce a significant increase in BOLD signal levels in these areas. In conclusion, active recharge burst and tonic SCS have different effects on the intensity and localization of SCS-induced activation responses in the brain. This work demonstrates that active recharge burst is another waveform that can engage brain areas associated with cognitive-emotional aspects of pain as well as areas associated with location and intensity of pain. Previous studies showing similar engagement used only passive recharge burst.