Spinal Cord Stimulation Trial Electrodes Rapidly Produce Epidural Scarring, Impeding Surgical Paddle Lead Placement.

OBJECTIVES: After a successful percutaneous cylindrical electrode five-to-seven-day trial of spinal cord stimulation, subsequent permanent surgical paddle lead (SPL) placement can be impeded by epidural scar induced by the trial leads (TLs). Our goal was to determine whether a delay between TL and subsequent SPL placement provokes enhanced epidural scarring with an increased need for laminotomy extension required for scar removal for optimal SPL placement. MATERIALS AND METHODS: Using a prospectively maintained data base, a single-facility/surgeon retrospective study identified 261 patients with newly placed thoracolumbar SPLs from June 2013 to November 2023. Data were obtained from the patients' charts, including, but not limited to, timing between TL and SPL, operative time, and need for extension of laminotomy. RESULTS: We found that the need for laminotomy extension due to TL epidural scarring and longer operative times was not required in our patients if the SPL was placed within ten days of placement of the TL (0/26), leading to shorter operative times in those with SPL placed after ten days (122.42 ± 10.72 minutes vs 140.75 ± 4.72 minutes; p = 0.005). We found no association with other medical comorbidities that may be confounding factors leading to epidural scarring/extension of laminotomy or association with level of SPL placement, size of the spinal canal, or indication for SPL placement. CONCLUSIONS: TL placement leads to scarring in the epidural space that appears to mature after ten days of its placement. In approximately 34% of patients, this leads to prolonged operative time owing to the need for extension of laminotomy and subsequent clearing of epidural scar for optimal SPL placement.

The Neurostimulation Appropriateness Consensus Committee (NACC)®: Recommendations for the Mitigation of Complications of Neurostimulation.

INTRODUCTION: The International Neuromodulation Society convened a multispecialty group of physicians based on expertise and international representation to establish evidence-based guidance on the mitigation of neuromodulation complications. This Neurostimulation Appropriateness Consensus Committee (NACC)® project intends to update evidence-based guidance and offer expert opinion that will improve efficacy and safety. MATERIALS AND METHODS: Authors were chosen on the basis of their clinical expertise, familiarity with the peer-reviewed literature, research productivity, and contributions to the neuromodulation literature. Section leaders supervised literature searches of MEDLINE, BioMed Central, Current Contents Connect, Embase, International Pharmaceutical Abstracts, Web of Science, Google Scholar, and PubMed from 2017 (when NACC last published guidelines) to October 2023. Identified studies were graded using the United States Preventive Services Task Force criteria for evidence and certainty of net benefit. Recommendations are based on the strength of evidence or consensus when evidence was scant. RESULTS: The NACC examined the published literature and established evidence- and consensus-based recommendations to guide best practices. Additional guidance will occur as new evidence is developed in future iterations of this process. CONCLUSIONS: The NACC recommends best practices regarding the mitigation of complications associated with neurostimulation to improve safety and efficacy. The evidence- and consensus-based recommendations should be used as a guide to assist decision-making when clinically appropriate.

Deep Brain Stimulation for Chronic Cluster Headaches: A Systematic Review and Meta-Analysis.

BACKGROUND: Chronic cluster headache (CCH) is a severe and debilitating sub-type of trigeminal autonomic cephalalgia that can be resistant to medical management and associated with significant impairment in quality of life. Studies of deep brain stimulation (DBS) for CCH have provided promising results but have not been assessed in a comprehensive systematic review/meta-analysis. OBJECTIVE: The objective was to perform a systematic literature review and meta-analysis of patients with CCH treated with DBS to provide insight on safety and efficacy. METHODS: A systematic review and meta-analysis were performed according to PRISMA 2020 guidelines. 16 studies were included in final analysis. A random-effects model was used to meta-analyze data. RESULTS: Sixteen studies reported 108 cases for data extraction and analysis. DBS was feasible in >99% of cases and was performed either awake or asleep. Meta-analysis revealed that the mean difference in headache attack frequency and headache intensity after DBS were statistically significant (p < 0.0001). Utilization of microelectrode recording was associated with statistically significant improvement in headache intensity postoperatively (p = 0.006). The average overall follow-up period was 45.4 months and ranged from 1 to 144 months. Death occurred in <1%. The rate of major complications was 16.67%. CONCLUSIONS: DBS for CCHs is a feasible surgical technique with a reasonable safety profile that can be successfully performed either awake or asleep. In carefully selected patients, approximately 70% of patients achieve excellent control of their headaches.

Functional Connectivity Magnetic Resonance Imaging Sequences in Patients With Postsurgical Persistent Spinal Pain Syndrome Type 2 With Implanted Spinal Cord Stimulation Systems: A Safety, Feasibility, and Validity Study.

BACKGROUND: Chronic pain has been associated with alterations in brain connectivity, both within networks (regional) and between networks (cross-network connectivity). Functional connectivity (FC) data on chronic back pain are limited and based on heterogeneous pain populations. Patients with postsurgical persistent spinal pain syndrome (PSPS) type 2 are good candidates for spinal cord stimulation (SCS) therapy. We hypothesize that 1) FC magnetic resonance imaging (fcMRI) scans can be safely obtained in patients with PSPS type 2 with implanted therapeutic SCS devices and that 2) their cross-network connectivity patterns are altered and involve emotion and reward/aversion functions. MATERIALS AND METHODS: Resting-state (RS) fcMRI (rsfcMRI) scans were obtained from nine patients with PSPS type 2 implanted with therapeutic SCS systems and 13 age-matched controls. Seven RS networks were analyzed, including the striatum. RESULTS: Cross-network FC sequences were safely obtained on a 3T MRI scanner in all nine patients with PSPS type 2 with implanted SCS systems. FC patterns involving emotion/reward brain circuitry were altered as compared with controls. Patients with a history of constant neuropathic pain, experiencing longer therapeutic effects of SCS, had fewer alterations in their connectivity patterns. CONCLUSIONS: To our knowledge, this is the first report of altered cross-network FC involving emotion/reward brain circuitry in a homogeneous population of patients with chronic pain with fully implanted SCS systems, on a 3T MRI scanner. All rsfcMRI studies were safe and well tolerated by all nine patients, with no detectable effects on the implanted devices.

Preoperative Thoracic Spine Magnetic Resonance Imaging for Spinal Cord Stimulation: Should Such a Recommendation Be an Absolute Requirement?

OBJECTIVE: Current published guidelines recommend advanced imaging, specifically, thoracic magnetic resonance imaging (MRI), prior to implantation of epidural paddle spinal cord stimulator (SCS) leads. Preoperative imaging may affect surgical approach to minimize risk of complications. We aimed to assess the impact of preoperative thoracic MRI on surgical planning in a large series of surgical paddle SCS lead placements in a real-world setting. MATERIALS AND METHODS: This is a retrospective study of a prospectively maintained data base of 160 patients treated by SCS with awake thoracic surgical paddle lead placement in a single academic functional neurosurgery center from 2013 to 2021. All patients had a thoracic MRI prior to implantation. Abnormal MRI findings were reviewed to determine their potential impact on the safety of surgical paddle lead placement. A minor impact was defined as anatomical areas to avoid with paddle lead placement. Major impacts included significant deviations from standard approach to electrode placement. RESULTS: None of the 160 patients had signs or symptoms referable to thoracic spine pathology prior to lead implant. Sixty-seven had abnormal thoracic MRI findings, and 36 had abnormal MRI findings that impacted surgical planning. Thirty-one patients had MRI findings with minor impact. Five patients (more than 3%) had findings with major impact. CONCLUSIONS: This is the largest case series assessing the impact of preoperative thoracic MRI on surgical planning for patients undergoing paddle SCS placement. Twenty-two percent of patients had MRI findings that impacted surgical planning with 3% requiring additional surgical decompression for safe paddle lead placement. Without advanced imaging to inform surgical planning, unnecessary risk may have been placed on these patients. Although such imaging has been recommended by consensus committees in published guidelines, our study is the first to present a large institutional experience of real-world data that demonstrates its importance.

The Neurostimulation Appropriateness Consensus Committee (NACC): Recommendations for Surgical Technique for Spinal Cord Stimulation.

INTRODUCTION: The field of neurostimulation for the treatment of chronic pain is a rapidly developing area of medicine. Although neurostimulation therapies have advanced significantly as a result of technologic improvements, surgical planning, device placement, and postoperative care are of equal importance to optimize outcomes. This Neurostimulation Appropriateness Consensus Committee (NACC) project intends to provide evidence-based guidance for these often-overlooked areas of neurostimulation practice. MATERIALS AND METHODS: Authors were chosen based on their clinical expertise, familiarity with the peer-reviewed literature, research productivity, and contributions to the neuromodulation literature. Section leaders supervised literature searches of MEDLINE, BioMed Central, Current Contents Connect, Embase, International Pharmaceutical Abstracts, Web of Science, Google Scholar, and PubMed from the last NACC publication in 2017 to the present. Identified studies were graded using the United States Preventive Services Task Force criteria for evidence and certainty of net benefit. Recommendations are based on evidence strength and consensus when evidence was scant. RESULTS: This NACC project provides guidance on preoperative assessment, intraoperative techniques, and postoperative management in the form of consensus points with supportive evidence. These results are based on grade of evidence, strength of consensus, and expert opinion. CONCLUSIONS: The NACC has given guidance for a surgical plan that encompasses the patient journey from the planning stage through the surgical experience and postoperative care. The overall recommendations are designed to improve efficacy and the safety of patients undergoing these neuromodulation procedures and are intended to apply throughout the international community.

The Neurostimulation Appropriateness Consensus Committee (NACC): Recommendations on Best Practices for Cervical Neurostimulation.

INTRODUCTION: The International Neuromodulation Society convened a multispecialty group of physicians based on expertise with international representation to establish evidence-based guidance on the use of neurostimulation in the cervical region to improve outcomes. This Neurostimulation Appropriateness Consensus Committee (NACC) project intends to provide evidence-based guidance for an often-overlooked area of neurostimulation practice. MATERIALS AND METHODS: Authors were chosen based upon their clinical expertise, familiarity with the peer-reviewed literature, research productivity, and contributions to the neuromodulation literature. Section leaders supervised literature searches of MEDLINE, BioMed Central, Current Contents Connect, Embase, International Pharmaceutical Abstracts, Web of Science, Google Scholar, and PubMed from 2017 (when NACC last published guidelines) to the present. Identified studies were graded using the US Preventive Services Task Force criteria for evidence and certainty of net benefit. Recommendations are based on the strength of evidence or consensus when evidence was scant. RESULTS: The NACC examined the published literature and established evidence- and consensus-based recommendations to guide best practices. Additional guidance will occur as new evidence is developed in future iterations of this process. CONCLUSIONS: The NACC recommends best practices regarding the use of cervical neuromodulation to improve safety and efficacy. The evidence- and consensus-based recommendations should be utilized as a guide to assist decision making when clinically appropriate.

Low Rate of Intrathecal Baclofen Pump Catheter-Related Complications: Long-Term Study in Over 100 Adult Patients Associated With Reinforced Catheter.

OBJECTIVES: Intrathecal baclofen (ITB) is a cost-effective therapy for patients with severe spasticity. The most common complications are catheter-related complications (CRCs) including kinking/occlusion, blockage, migration, fracture, disconnection, and CSF leak. Our objective was to determine the CRC rate in a large cohort of adults with newly implanted ITB pump systems with polymer reinforced silicone catheters. MATERIALS AND METHODS: This is a retrospective study of a prospectively maintained database consisting of patients who had undergone implantation of ITB pump systems with Ascenda (Medtronic, Minneapolis) catheters from 2013 to 2020. Over this seven-year period, 141 patients underwent ITB pump system implantations; 126 of which had a minimum of one-year follow-up. RESULTS: The 126 patients with a minimum of one year follow-up (average 43 month; range 12-89), had an average age of 51 years (63% male). Severe spasticity was due to spinal cord injury (38%), traumatic brain injury (15%), cerebral palsy (13%), multiple sclerosis (11%), stroke (10%), and other (13%). Nine (7.1%) CRCs occurred in 7 (5.6%) patients (median 6 mo. post-implant): 5 intrathecal catheter occlusions (range 3-52 months post-implant), two fractures in one patient (6 months), one disconnection at the catheter pump interface (2 months), and one due to kinking at 84 months No migrations occurred. CONCLUSIONS: Reported CRCs have been high for ITB pump systems. Ours is the first large cohort, long-term study of CRCs related to reinforced catheters; additionally, our low CRC rate compares favorably to previously published data. Thus, implantation of reinforced catheters may be associated with a low CRC rate.

Non-Infectious Peri-Electrode Edema and Contrast Enhancement Following Deep Brain Stimulation Surgery.

BACKGROUND: Dramatic radiographic abnormalities seen after electrode placement (DRAAEP) in deep brain stimulation (DBS) surgery is rare and it has not been associated with infection or hemorrhage. It has consisted of peri-electrode low-attenuation signals on CT scans and extensive T2-hyperintense signals without associated contrast enhancement (CE) on MRI scans. OBJECTIVE: Report on the management of a patient with Parkinson's disease (PD) presenting with a seizure and findings of DRAAEP with positive CE 12 days after the placement of a subthalamic nucleus (STN) DBS electrode. METHODS: Head CT and contrasted brain MRI scans were completed on presentation. Standard laboratory work up was obtained to evaluate for infection. Operative exploration deep to the burr-hole site surrounding the electrode was performed and cultures were obtained. Serial contrasted MRI scans were completed to determine the abnormal signal duration. RESULTS: A MRI revealed extensive T2-hyperintensity and positive CE concentrated around the burr-hole site surrounding the electrode. Intraoperative exploration revealed no evidence of infection and electrode revision was avoided. There was near resolution of the abnormal T2 signal and CE at six weeks from detection. The patient remained without signs of intracranial infection and responded well to DBS. CONCLUSION: To our knowledge, this is the first reported case of DRAAEP with positive gadolinium enhancement. Despite the extensive contrast enhancement, these DRAAEP appear to remain benign transient events that, in the absence of clinical signs of infection or neurologic decline, may warrant no further aggressive intervention such as hardware removal.

A Novel Nonanchoring Technique for Implantation of Paddle Leads in the Cervical Spine Under Conscious Sedation.

OBJECTIVES: Spinal cord stimulation (SCS) revision surgery remains common, with a negative impact on cost-effectiveness and outcomes. The primary goal of this report was to retrospectively study the need for revision surgery in a cohort of complex regional pain syndrome type I (CRPS-1) patients with newly implanted cervical surgical paddle leads, focusing on a method of implantation to reduce the need for revision surgery. METHODS: Fifteen patients underwent implantation of paddle SCS leads in the cervical spine with cervical laminotomies under conscious sedation for CRPS-1 from 2008 to 2012. Electrodes were not anchored and 11 of the electrodes were three-column paddle leads. A disinterested third party performed initial chart reviews, supplemented by subsequent telephone interviews. The need for revision surgery was the endpoint. A single surgeon performed all implants with a consistent method. RESULTS: There were no paddle electrode lead revisions required for suboptimal lead placement, fracture, migration, or infection at a median follow-up period of 22 months. CONCLUSIONS: This study is the first to report on: 1) cervical electrode implantation with no anchoring; and 2) cervical paddle lead implantation (including three-column paddles) performed under conscious sedation. The specific method of nonanchoring of the paddle implants under conscious sedation may have contributed to low electrode lead revision rates.

Incidence of Revision Surgery in a Large Cohort of Patients With Thoracic Surgical Three-Column Paddle Leads: A Retrospective Case Review.

OBJECTIVES: Spinal cord stimulation (SCS) revision surgery remains common, with a negative impact on cost-effectiveness and outcomes. The primary goal in this report was to retrospectively study the need for revision surgery in a large cohort of patients with newly implanted thoracic surgical three-column paddle leads, focusing on a method of implantation to reduce the need for revision surgery. Clinical outcomes were also assessed. METHODS: The outcomes in 126 patients who received initial surgical paddle SCS implants for back and/or leg pain from 2008 to 2012 were retrospectively analyzed. A disinterested third party performed chart reviews and telephone interviews. A single surgeon with a consistent method performed all implants, with no lead anchoring. All three major commercial vendors were utilized. RESULTS: There were no paddle electrode lead revisions required for spontaneous fracture, migration, or infection at an average chart-review follow-up period of 20 months. With subsequent telephone interviews, a 65% clinical success rate was seen at 29 months. Significant suboptimal stimulation with body-position changes (SSBPC) was reported in less than 10% of patients. All results were vendor-independent. CONCLUSIONS: This report, the largest to date on patients with three-column paddle leads, shows low electrode revision rates with expected clinical success rates. Clinically relevant SSBPC was uncommon.

Surgical paddle-lead placement for screening trials of spinal cord stimulation.

OBJECTIVES: Spinal cord stimulation (SCS) has become an evidence-based treatment for a variety of chronic pain disorders. A key step in appropriate patient selection and long-term outcome predictability is a percutaneous screening trial of stimulation. Occasionally, a trial cannot be adequately completed with a percutaneous electrode. Rather than depriving this therapy from these patients, the authors have developed a program providing surgically implanted paddle-lead screening trials of SCS. METHODS: Data from 22 patients undergoing paddle-lead screening trials of SCS from October 2009 to August 2012 were retrospectively reviewed. The surgical paddle leads were positioned with thoracic or cervical laminotomies under local anesthetic and conscious sedation, allowing awakened patients to confirm optimal lead placement. Externalized lead extensions were connected to an external pulse generator for a five-day screening trial. Pain reduction of at least 50% was required for patients to have the previously implanted paddle lead connected to an internalized pulse generator; otherwise, the trial surgical paddle leads were removed. RESULTS: Twenty-two patients received five-day paddle-lead stimulation screening trials for various chronic neuropathic pain conditions. All paddle screening trials were well tolerated and completed as outpatient procedures. Sixteen patients received fully implanted systems. At an average follow-up of 23 months, all implanted patients continue to have satisfactory pain control. There were no infections, lead migrations, or revisions. CONCLUSIONS: Surgically implanted paddle-lead screening trials of SCS can be used safely and effectively in those patients in which an adequate percutaneous-electrode trial cannot be completed. Results are similar to those seen with standard percutaneous screening trials. A systematic approach to surgical-paddle screening trials of SCS has not been previously reported.

Restoration of altered somatosensory cortical representation with spinal cord stimulation therapy in a patient with complex regional pain syndrome: a magnetoencephalography case study.

OBJECTIVES: Development of effective chronic pain treatment strategies has been hampered by the lack of an objective pain biomarker. Magnetoencephalography (MEG) has demonstrated cortical disorganization corresponding to the affected limb of complex regional pain syndrome (CRPS) patients and spinal cord stimulation (SCS) can acutely treat CRPS in a reversible and adjustable fashion. In order to better define a potential MEG-sensitive biomarker for chronic pain, our goal was to study the effects of therapeutic SCS on cortical disorganization in patients with unilateral limb CRPS. METHODS: Two patients treated with either thoracic or cervical SCS with leg or arm CRPS were studied with MEG. Baseline and tactile-evoked responses were recorded with and without effective SCS therapy. RESULTS: All MEG recordings were obtained with minimal interference. In the patient with arm CRPS, with the stimulator off, first and fifth digit primary somatosensory (SI) cortical representations (D1/D5) were significantly disorganized and spatially inverted as compared with the opposite unaffected limb. Effective SCS therapy was then able to acutely normalize or restore hand cortical organization in the affected CRPS limb. This restoration of cortical organization was partially maintained with lingering pain relief when the stimulator was subsequently turned off. CONCLUSIONS: This is the first report of a MEG study showing D1/D5 cortical disorganization and its apparent reversal or restoration with cervical SCS therapy. Ours also is the first report of an apparent acute reversible interchange in the cortical representations of D1 and D5. Our limited data demonstrate that disorganization of SI cortex might be a neurophysiologic marker of chronic pain as shown with instantaneous normalization of SI disorganization or restoration of SI organization with therapeutic SCS. As a clinically proven tool for functional mapping, MEG might be shown to provide an objective measure of chronic pain. More data are required to further investigate this possibility.

Distinct Functional Connectivity Patterns for Intermittent Vs Constant Neuropathic Pain Phenotypes in Persistent Spinal Pain Syndrome Type 2 Patients.

Background: Chronic low back pain (cLBP) has been associated with alterations in brain functional connectivity (FC) but based upon heterogeneous populations and single network analyses. Our goal is to study a more homogeneous cLBP population and focus on multiple cross-network (CN) connectivity analysis. We hypothesize that within this population: 1) altered CN FC, involving emotion and reward/aversion functions are related to their pain levels and 2) altered relationships are dependent upon pain phenotype (constant neuropathic vs intermittent pain). Methods: In this case series, resting state fcMRI scans were obtained over a study duration of 60 months from 23 patients (13 constant neuropathic and 10 intermittent pain) with Persistent Spinal Pain Syndrome (PSPS Type 2) being considered for spinal cord stimulation (SCS) therapy at a single academic center. Images were acquired using a Discovery MR750 GE scanner. During the resting state acquisitions, they were asked to close their eyes and relax. The CN analysis was performed on 7 brain networks and compared to age-matched controls. Linear regression was used to test the correlation between CN connectivity and pain scores. Results: CN FC involving emotion networks (STM: striatum network index) was significantly lower than controls in all patients, regardless of pain phenotype (P < 0.003). Pain levels were positively correlated with emotional FC for intermittent pain but negatively correlated for constant pain. Conclusion: This is the first report of 1) altered CN FC involving emotion/reward brain circuitry in 2) a homogeneous population of cLBP patients with 3) two different pain phenotypes (constant vs intermittent) in PSPS Type 2 patients being considered for SCS. FC patterns were altered in cLBP patients as compared to controls and were characteristic for each pain phenotype. These data support fcMRI as a potential and objective tool in assessing pain levels in cLBP patients with different pain phenotypes.

Large-scale brain networks and intra-axial tumor surgery: a narrative review of functional mapping techniques, critical needs, and scientific opportunities.

In recent years, a paradigm shift in neuroscience has been occurring from "localizationism," or the idea that the brain is organized into separately functioning modules, toward "connectomics," or the idea that interconnected nodes form networks as the underlying substrates of behavior and thought. Accordingly, our understanding of mechanisms of neurological function, dysfunction, and recovery has evolved to include connections, disconnections, and reconnections. Brain tumors provide a unique opportunity to probe large-scale neural networks with focal and sometimes reversible lesions, allowing neuroscientists the unique opportunity to directly test newly formed hypotheses about underlying brain structural-functional relationships and network properties. Moreover, if a more complete model of neurological dysfunction is to be defined as a "disconnectome," potential avenues for recovery might be mapped through a "reconnectome." Such insight may open the door to novel therapeutic approaches where previous attempts have failed. In this review, we briefly delve into the most clinically relevant neural networks and brain mapping techniques, and we examine how they are being applied to modern neurosurgical brain tumor practices. We then explore how brain tumors might teach us more about mechanisms of global brain dysfunction and recovery through pre- and postoperative longitudinal connectomic and behavioral analyses.

Responsive Neurostimulation of the Anterior Thalamic Nuclei in Refractory Genetic Generalized Epilepsy: A Case Series.

Genetic generalized epilepsies (GGEs) are thought to represent disorders of thalamocortical networks. There are currently no well-established non-pharmacologic treatment options for patients with drug-resistant GGE. NeuroPace's Responsive Neurostimulation (RNS) System was approved by the United States Food and Drug Administration to treat focal seizures with up to two ictal foci. We report on three adults with drug-resistant GGE who were treated with thalamic RNS. Given the severity of their epilepsies and the potential ictogenic role of the thalamus in the pathophysiology of GGE, the RNS System was palliatively implanted with leads in the bilateral anterior thalamic nuclei (ANT) of these patients. The ANT was selected because it was demonstrated to be a safe target. We retrospectively evaluated metrics including seizure frequency over 18-32 months. One patient required explantation due to infection. The other two patients were clinical responders. By the end of the observation period reported here, one patient was seizure-free for over 9 months. All three self-reported an improved quality of life. The clinical response observed in these patients provides 'proof-of-principle' that GGE may be treatable with responsive thalamic stimulation. Our results support proceeding to a larger study investigating the efficacy and safety of thalamic RNS in drug-resistant GGE.

Spinal Cord Stimulation for Neurogenic Claudication Associated with Lumbar Spinal Stenosis.

BACKGROUND: There is a debate on the long-term outcomes of surgical decompression for lumbar spinal stenosis (LSS) as compared to conservative treatment, with even more limited outcomes in repeat surgeries. Hence, other less invasive treatment modalities, such as neuromodulation with a modern spinal cord stimulator (SCS), could be considered in the spectrum of management options for symptoms of neurogenic claudication (NC) related to LSS as an alternative to surgery. OBJECTIVE: Assessing the outcomes and efficacy of SCS in neurogenic claudication in patients with or without a prior lumbar surgery. STUDY DESIGN: This is a retrospective study of a prospectively collected database. SETTING: The research was conducted at the Medical College of Wisconsin (MCW), an academic medical center, in Milwaukee, Wisconsin. METHODS: This study reviewed all patients who had undergone SCS therapy for symptoms consistent with NC between 2013 through 2020. The data were collected from MCW. Only patients with at least one year of follow-up were included in outcome assessment. RESULTS: One hundred and eighteen patients with primary symptoms of NC underwent an SCS trial with an 86% pass-rate. A total of 69 of the 93 patients who underwent permanent SCS implantation had at least one year of follow-up. All patients reported initial improvement after permanent implantation. At one-year follow-up, 55 (80%) patients had sustained improvement of their pain levels and claudication symptoms, of whom 52 (75%) continued to experience benefit for an average of at least 27 months. For patients with no prior surgical decompression, 86% continued to experience sustained benefit at the latest follow-up. LIMITATIONS: This study has several limitations. It is of a retrospective nature that includes selection and recall biases. It is a single-center study that limits its generalizability. More limitations are discussed in the main article. CONCLUSIONS: With modern SCS techniques, the majority of patients can achieve sustained improvement of symptoms of NC of at least a 2-year duration regardless of previous history of lumbar decompressive surgery. SCS can be considered as part of the conservative treatment options before committing to surgical decompression.

Long-term follow-up study of chronic deep brain stimulation of the subthalamic nucleus for cervical dystonia.

Objectives. Medically refractory cervical dystonia has recently been treated using deep brain stimulation (DBS), targeting the subthalamic nucleus (STN). There has been limited literature regarding short-term outcomes and no literature regarding long-term outcomes for refractory cervical dystonia following DBS of the STN. Materials and Methods. Two patients with medically refractory cervical dystonia underwent STN DBS. Patients were rated using the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) preoperatively and immediately postoperatively as well as just prior to turning on the stimulators and subsequently at 24-48 hours, six months, one, two, and three years after stimulation. Microrecordings were used to identify the STN and substantia nigra reticulata (SNr). Results. Significant immediate and sustained long-term improvements were seen in motor, disability, pain, and total TWSTRS scores. In one patient, only unilateral stimulation was required. The STN and SNr were easily identified as having activity similar to off-state Parkinson's patients. Conclusions. DBS therapy for cervical dystonia utilizing the STN as the surgical target may be novel and may be an alternative target to the globus pallidus internus as supported by this first long-term outcome report. Further studies need to be performed to confirm these conclusions.

Functional connectivity and structural analysis of trial spinal cord stimulation responders in failed back surgery syndrome.

BACKGROUND: Chronic pain has been associated with alterations in brain structure and function that appear dependent on pain phenotype. Functional connectivity (FC) data on chronic back pain (CBP) is limited and based on heterogeneous pain populations. We hypothesize that failed back surgery syndrome (FBSS) patients being considered for spinal cord stimulation (SCS) therapy have altered resting state (RS) FC cross-network patterns that 1) specifically involve emotion and reward/aversion functions and 2) are related to pain scores. METHODS: RS functional MRI (fMRI) scans were obtained for 10 FBSS patients who are being considered for but who have not yet undergone implantation of a permanent SCS device and 12 healthy age-matched controls. Seven RS networks were analyzed including the striatum (STM). The Wilcoxon signed-rank test evaluated differences in cross-network FC strength (FCS). Differences in periaqueductal grey (PAG) FC were assessed with seed-based analysis. RESULTS: Cross-network FCS was decreased (p<0.05) between the STM and all other networks in these FBSS patients. There was a negative linear relationship (R2 = 0.76, p<0.0022) between STMFCS index and pain scores. The PAG showed decreased FC with network elements and amygdala but increased FC with the sensorimotor cortex and cingulate gyrus. CONCLUSIONS: Decreased FC between STM and other RS networks in FBSS has not been previously reported. This STMFCS index may represent a more objective measure of chronic pain specific to FBSS which may help guide patient selection for SCS and subsequent management.

Care Bundle Approach to Minimizing Infection Rates after Neurosurgical Implants for Neuromodulation: A Single-Surgeon Experience.

INTRODUCTION: Implant-related infections carry a high morbidity. Infectious rates for neuromodulation implants range from 1% to 9% for deep brain stimulation (DBS), 0% to 10% for spinal cord stimulation (SCS) systems, and 3% to 15% for intrathecal (IT) pump systems. Meanwhile, studies of care bundles report infection rate reduction to 1.0% for SCS and 0.3% for cardiac implants. Herein, we evaluate the effectiveness of an infection prevention bundle (IPB) in minimizing infections after surgeries for neuromodulation implants. METHODS: An IPB focused on preoperative checklists, screening questionnaires, methicillin-resistant and methicillin-sensitive Staphylococcus aureus decolonization, weight-based antibiotic prophylaxis, strict draping and surgical techniques, and wound care education was implemented in our functional neurosurgery division in April 2015. We retrospectively reviewed all surgeries for implantation or replacement of SCS, DBS, and IT pump system components from March 2013 to October 2017. The patients were divided into pre-IPB and post-IPB groups. All procedures were performed by a single surgeon. Each surgical site was considered a unique surgical case. Infection rates were calculated for pre-IPB and post-IPB groups. RESULTS: A total of 688 patients underwent 1161 unique surgical procedures (222 DBS electrodes, 419 IPG, 203 SCS, 317 IT pumps) during the study period. There were 546 pre-IPB and 615 post-IPB surgical procedures. The pre-IPB infection rates were 0%, 1.3%, and 8.7% for SCS, DBS, and IT pumps, respectively. The post-IPB infection rates were 0%, 0.3%, and 1.8% for SCS, DBS, and IT pumps, respectively. CONCLUSIONS: Implementation of a standardized IPB approach reduced the number of infections for all neuromodulation implants studied. This approach can be adopted within any specialty to potentially decrease the incidence of implant-related infections.