Is spinal cord stimulation safe? A review of 13 years of implantations and complications

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.

Large-scale real-world data on a multidisciplinary approach to spinal cord stimulation for persistent spinal pain syndromes: first evaluation of the Neuro-Pain® nationwide screening and follow-up interactive register

Introduction

Spinal cord stimulation is a common treatment option for neuropathic pain conditions. Despite its extensive use and multiple technological evolutions, long term efficacy of spinal cord stimulation is debated. Most studies on spinal cord stimulation include a rather limited number of patients and/or follow-ups over a limited period. Therefore, there is an urgent need for real-world, long-term data.

Methods

In 2018, the Belgian government initiated a nationwide secure platform for the follow-up of all new and existing spinal cord stimulation therapies. This is a unique approach used worldwide. Four years after the start of centralized recording, the first global extraction of data was performed.

Results

Herein, we present the findings, detailing the different steps in the centralized procedure, as well as the observed patient and treatment characteristics. Furthermore, we identified dropouts during the screening process, the reasons behind discontinuation, and the evolution of key indicators during the trial period. In addition, we obtained the first insights into the evolution of the clinical impact of permanent implants on the overall functioning and quality of life of patients in the long-term.

Discussion

Although these findings are the results of the first data extraction, some interesting conclusions can be drawn. The long-term outcomes of neuromodulation are complex and subject to many variables. Future data extraction will allow us to identify these confounding factors and the early predictors of success. In addition, we will propose further optimization of the current process.

Incidence of Neuraxial and Non-Neuraxial Hematoma Complications From Spinal Cord Stimulator Surgery: Systematic Review and Proportional Meta-Analysis

OBJECTIVE

The goal of this meta-analysis was to estimate the incidence of total hematomas, neuraxial hematomas, and non-neuraxial hematomas in patients who underwent temporary spinal cord stimulator (SCS) lead trial placement and permanent implantation of SCS leads and internal pulse generator (IPG).

MATERIALS AND METHODS

A comprehensive search was conducted of databases of any publications before October 21, 2021. Eligible study designs included randomized control trials and prospective or retrospective observational studies with more than ten patients. The primary outcome variables were the incidences of total hematomas, neuraxial hematomas, and non-neuraxial hematomas in patients with SCS. These dichotomous categorical outcomes were abstracted from studies after Freeman-Tukey arcsine square root transformation using random-effects meta-analysis (DerSimonian and Laird method). Pooled incidence rates and 95% CIs were calculated for each outcome variable.

RESULTS

A total of 40 studies met the inclusion criteria. Included in the neuraxial and non-neuraxial hematoma analyses were 4751 patients and 3862 patients, respectively. The pooled incidence of any hematoma in patients with SCS was 0.81% (95% CI, 0.45%-1.27%). The pooled incidence of neuraxial hematoma in patients with SCS was 0.32% (95% CI, 0.18%-0.50%). This included primarily epidural hematomas (11/4751) but also comprised an intracranial hemorrhage in a patient on enoxaparin bridge therapy from warfarin and one patient not on anticoagulation with an intracranial subdural hematoma that resulted in death. The pooled incidence of non-neuraxial hematomas in patients with SCS was 0.59% (95% CI, 0.29%-1.00%).

CONCLUSION

The overall incidence of hematomas in patients with temporary SCS trial lead placement and permanent SCS/IPG implantations is less than 1%. Furthermore, the incidence of neuraxial hematomas is less than 0.5%, which is of particular interest given the potential devastating consequences of this complication. The results of this study can be used to inform patients and implanting physicians on hematoma complications from SCS and highlight that the benefits of SCS outweigh the hematoma risks if anticoagulation is appropriately managed perioperatively.

Beyond treatment of chronic pain: a scoping review about epidural electrical spinal cord stimulation to restore sensorimotor and autonomic function after spinal cord injury

Epidural electrical epinal cord stimulation (ESCS) is an established therapeutic option in various chronic pain conditions. In the last decade, proof-of-concept studies have demonstrated that ESCS in combination with task-oriented rehabilitative interventions can partially restore motor function and neurological recovery after spinal cord injury (SCI). In addition to the ESCS applications for improvement of upper and lower extremity function, ESCS has been investigated for treatment of autonomic dysfunction after SCI such as orthostatic hypotension. The aim of this overview is to present the background of ESCS, emerging concepts and its readiness to become a routine therapy in SCI beyond treatment of chronic pain conditions.

Efficacy and Safety of 10 kHz Spinal Cord Stimulation Using Cervical and Thoracic Leads: A Single-Center Retrospective Experience

INTRODUCTION

Spinal cord stimulation (SCS) with lower thoracic leads has been studied extensively. However, the evidence base for cervical SCS is less well developed, and reports of multiarea SCS lead placement are uncommon. Therefore, this single-center retrospective study evaluated outcomes from 10-kHz SCS with cervical or combined cervical and thoracic lead placement.

METHOD

All patients that underwent a 10-kHz SCS trial with either cervical or combined cervical and thoracic lead placement between 2015 and 2020 were included in our study. We reviewed patient's charts for demographic information, lead placement, and pain scores up to 48 months after implantation.

RESULTS

Of the 105 patients that underwent a 10-kHz SCS trial during the review period, 92 (88%) had back/neck or extremity pain that responded to therapy (≥ 50% pain relief from baseline) and received a permanent system. Sixty-two of these patients (67%) were implanted with combined cervical and thoracic leads, while 30 (33%) received cervical-only leads. Pain relief in both regions exceeded 60% at most visits throughout the 48-month study period. Throughout follow-up, the responder rate in both pain areas was consistently ≥ 70%. No unexpected adverse events occurred.

CONCLUSION

The 10-kHz SCS provided effective and durable pain relief with either cervical or combined cervical and thoracic leads. The efficacy and safety profile of both applications appears to be comparable to lower thoracic SCS. Our results suggest that 10-kHz SCS is a useful paresthesia-free therapeutic option for chronic neuropathic pain originating in the cervical area, as well as more complex multiarea pain presentations.

Spinal Cord Stimulation via Percutaneous and Open Implantation: Systematic Review and Meta-Analysis Examining Complication Rates

BACKGROUND

Spinal cord stimulation (SCS) has become a successful therapeutic option for combating chronic pain and can be implanted via percutaneous or open (laminotomy/laminectomy) techniques. This study aimed to systematically review the complications that occur after SCS placement via percutaneous and open (laminotomy/laminectomy) in failed back surgery syndrome (FBSS), complex regional pain syndrome (CRPS), and chronic back (lumbosacral)/leg pain.

METHODS

The PubMed and Embase databases were searched from inception to June 2020; prospective studies using SCS in patients with FBSS, CRPS, and chronic low back pain that reported both complications and the implantation method used were included. Effects and results from each study were combined using a random-effects model and were structured for subgroup analysis between open implantation and percutaneous implantation. Meta-regression was performed by calculating a mean difference and weighted by inverse variance and 95% confidence intervals (CIs).

RESULTS

Thirty-two articles were included in this systematic review and meta-analysis. Using several different patient- and event-based metrics, our meta-analysis revealed an overall average complication rate of 21.1% (95% CI, 14.9-27.2). Equipment, technical, and medical complications occurred at rates of 12.1%, 1.1%, and 6.3%, respectively. Lead migration and infection rates were 5.6% and 3.8%, respectively. When comparing the 2 implant techniques, medical-related surgical reinterventions and explants due to infection were more common in open compared with percutaneous SCS procedures.

CONCLUSIONS

Equipment-related complications accounted for the majority of SCS complications. Percutaneous SCS resulted in less reintervention and fewer explants caused by medical-related complications and infection, respectively. These conclusions may provide a general understanding of the SCS complications profile for physicians who care for SCS patients.

The Use of Remote Programming for Spinal Cord Stimulation for Patients With Chronic Pain During the COVID-19 Outbreak in China

ObjectiveS

Due to the impact of COVID-19 epidemic, face-to-face follow-up treatments for patients with chronic pain and implanted spinal cord stimulation (SCS) devices are forced to be delayed or stopped. This has led to more follow ups being done remotely. Meanwhile, with the development of 4G/5G networks, smartphones, and novel devices, remote programming has become possible. Here, we investigated the demand and utility of remote follow-ups including remote programming for SCS for patients with chronic pain.

Materials and Methods

A questionnaire including questions on demographic characteristics, pain history, postimplantation life quality, standard follow-up experience, remote follow-up, and remote programming experience was sent to patients diagnosed as chronic intractable pain and treated with SCS during January 2019 to January 2020.

Results

A total of 64 participants completed the questionnaire. About 70% of participants expressed demands for remote follow-ups due to the inconvenience, high costs, and time consumption of traditional follow-up visits. Nearly 97% of participants have attempted remote follow-ups, and about 81% of participants have further tried remote programming. Approximately, 96% of them recognized the benefits.

Conclusions

The remote programming was in high demand among participants. Most of the participants have tried remote follow-ups or even remote programming. The remote programming appeared to be more efficient, economic and were widely recognized among participants.

Efficacy and Safety of 10 kHz Spinal Cord Stimulation for the Treatment of Chronic Pain: A Systematic Review and Narrative Synthesis of Real-World Retrospective Studies

10 kHz spinal cord stimulation (SCS) is increasingly utilized globally to treat chronic pain syndromes. Real-world evidence complementing randomized controlled trials supporting its use, has accumulated over the last decade. This systematic review aims to summarize the retrospective literature with reference to the efficacy and safety of 10 kHz SCS. We performed a systematic literature search of PubMed between 1 January 2009 and 21 August 2020 for English-language retrospective studies of ≥3 human subjects implanted with a Senza® 10 kHz SCS system and followed-up for ≥3 months. Two independent reviewers screened titles/abstracts of 327 studies and 46 full-text manuscripts. In total, 16 articles were eligible for inclusion; 15 reported effectiveness outcomes and 11 presented safety outcomes. Follow-up duration ranged from 6-34 months. Mean pain relief was >50% in most studies, regardless of follow-up duration. Responder rates ranged from 67-100% at ≤12 months follow-up, and from 46-76% thereafter. 32-71% of patients decreased opioid or nonopioid analgesia intake. Complication incidence rates were consistent with other published SCS literature. Findings suggest 10 kHz SCS provides safe and durable pain relief in pragmatic populations of chronic pain patients. Furthermore, it may decrease opioid requirements, highlighting the key role 10 kHz SCS can play in the medium-term management of chronic pain.

3D patient-specific spinal cord computational model for SCS management: potential clinical applications

BACKGROUND AND OBJECTIVE

Although Spinal Cord Stimulation (SCS) is an established therapy for treating neuropathic chronic pain, in tonic stimulation, postural changes, electrode migration or badly-positioned electrodes can produce annoying stimulation (intercostal neuralgia) in about 35% of the patients. SCS models are used to study the effect of electrical stimulation to better manage the stimulation parameters and electrode position. The goal of this work was to develop a realistic 3D patient-specific spinal cord model from a real patient and develop a future clinical application that would help physicians to optimize paresthesia coverage in SCS therapy.

METHODS

We developed two 3D patient-specific models from a high-resolution MRI of two patients undergoing SCS treatment. The model consisted of a finite element model of the spinal cord and a sensory myelinated nerve fiber model. The same simulations were performed with a generalized spinal cord model and we compared the results with the clinical data to evaluate the advantages of a patient-specific model. To identify the geometrical parameters that most influence the stimulation predictions, a sensitivity analysis was conducted. We used the patient-specific model to perform a clinical application involving the pre-implantation selection of electrode polarity and study the effect of electrode offset.

RESULTS

The patient-specific model correlated better with clinical data than the generalized model. Electrode-dura mater distance, dorsal CSF thickness, and CSF diameter are the geometrical parameters that caused significant changes in the stimulation predictions. Electrode polarity could be planned and optimized to stimulate the patient's painful dermatomes. The addition of offset in parallel electrodes would not have been beneficial for one of the patients of this study because they reduce neural activation displacement.

CONCLUSIONS

This is the first study to relate the activation area model prediction in dorsal columns with the clinical effect on paresthesia coverage. The outcomes show that 3D patient-specific models would help physicians to choose the best stimulation parameters to optimize neural activation and SCS therapy in tonic stimulation.

A Retrospective Review of Lead Migration Rate in Patients Permanently Implanted with Percutaneous Leads and a 10 kHz SCS Device

Background

Spinal cord stimulation (SCS) has been used over decades for pain management, but migration of percutaneous leads has been the most common complication. Better surgical techniques and newer SCS technologies likely reduced the incidence of lead migration requiring surgical revision, although data are sparse. This study aimed to retrospectively evaluate the incidence of clinically significant percutaneous lead migration in patients permanently implanted with a 10 kHz SCS system.

Methods

Consecutive patients with chronic trunk and/or limb pain, permanently implanted between January 2016 and June 2019, were included in the analysis. Data were collected from the hospital's electronic medical records and the manufacturer's database. Clinically significant lead migration, defined as diminished pain relief followed by surgery to correct lead location, was assessed at the 6-month follow-up.

Results

At the 6-month follow-up, there were no cases of clinically significant lead migration, average pain relief was 65.2%, 82% of patients had response (≥50% pain relief), improvement of function was noted in 72% of patients, and decrease of medication was observed in 42% of patients. Therapy efficacy was sustained in patients with >12 months follow-up; the average pain relief was 58.5%, and the response rate was 82%.

Conclusions

The surgical techniques in use today are designed to minimise the risk of percutaneous lead migration and may have reduced its incidence. In addition, new SCS systems may give greater opportunity to mitigate cases of minor lead movement using alternative stimulation programs.

Immediate Abdominal Pain after Placement of Thoracic Paddle Leads for Spinal Cord Stimulation: A Case Series

BACKGROUND

Spinal cord stimulation (SCS) is a well-established treatment modality for chronic pain. Thoracic radiculopathy has been reported as a complication of SCS paddle lead implantation by several authors and commonly presents as abdominal pain.

METHODS

We performed a search of all patients who underwent either placement of a new epidural paddle lead electrode or revision of an epidural paddle lead electrode for SCS in the thoracic region from January 2017 to January 2018. We then investigated all cases of immediate postoperative abdominal pain.

RESULTS

We identified 7 patients who had immediate postoperative abdominal pain among 86 cases of epidural SCS procedures. Most patients were discharged on postoperative days 1-3. No patients required revisions or removals of their SCS for any reason.

CONCLUSIONS

We conclude that the etiology of immediate postoperative abdominal pain after thoracic paddle lead implantation for SCS is most likely thoracic radiculopathy. We hypothesize that small, transient epidural hematomas could be the cause of this thoracic radiculopathy. We argue that all patients with immediate postoperative abdominal pain and no other neurologic deficits after thoracic paddle lead implantation for SCS should first be treated conservatively with observation and pain management.

Neurostimulation Devices for the Treatment of Neurologic Disorders

Rapid advancements in neurostimulation technologies are providing relief to an unprecedented number of patients affected by debilitating neurologic and psychiatric disorders. Neurostimulation therapies include invasive and noninvasive approaches that involve the application of electrical stimulation to drive neural function within a circuit. This review focuses on established invasive electrical stimulation systems used clinically to induce therapeutic neuromodulation of dysfunctional neural circuitry. These implantable neurostimulation systems target specific deep subcortical, cortical, spinal, cranial, and peripheral nerve structures to modulate neuronal activity, providing therapeutic effects for a myriad of neuropsychiatric disorders. Recent advances in neurotechnologies and neuroimaging, along with an increased understanding of neurocircuitry, are factors contributing to the rapid rise in the use of neurostimulation therapies to treat an increasingly wide range of neurologic and psychiatric disorders. Electrical stimulation technologies are evolving after remaining fairly stagnant for the past 30 years, moving toward potential closed-loop therapeutic control systems with the ability to deliver stimulation with higher spatial resolution to provide continuous customized neuromodulation for optimal clinical outcomes. Even so, there is still much to be learned about disease pathogenesis of these neurodegenerative and psychiatric disorders and the latent mechanisms of neurostimulation that provide therapeutic relief. This review provides an overview of the increasingly common stimulation systems, their clinical indications, and enabling technologies.

Neuropathic Pain after Spinal Surgery

Neuropathic pain after spinal surgery, the so-called failed back surgery syndrome (FBSS), is a frequently observed troublesome disease entity. Although medications may be effective to some degree, many patients continue experiencing intolerable pain and functional disability. Only gabapentin has been proven effective in patients with FBSS. No relevant studies regarding manipulation or physiotherapy for FBSS have been published. Spinal cord stimulation (SCS) has been widely investigated as a treatment option for chronic neuropathic pain, including FBSS. SCS was generally accepted to improve chronic back and leg pain, physical function, and sleep quality. Although the cost effectiveness of SCS has been proved in many studies, its routine application is limited considering that it is invasive and is associated with safety issues. Percutaneous epidural adhesiolysis has also shown good clinical outcomes; however, its effects persisted for only a short period. Because none of the current methods provide absolute superiority in terms of clinical outcomes, a multidisciplinary approach is required to manage this complex disease. Further studies concerning the etiology, diagnosis, treatment, and cost effectiveness of FBSS are warranted to deepen our understanding of this condition.

High-Density in Spinal Cord stimulation: Virtual Expert Registry (DISCOVER): Study Protocol for a Prospective Observational Trial

Background

Spinal cord stimulation (SCS) is a proven and effective treatment for neuropathic pain conditions such as failed back surgery syndrome (FBSS). The hypothesis that different settings for SCS parameters activate unique, pain-relieving mechanisms has boosted the development of various SCS paradigms. High density spinal cord stimulation (HD-SCS) is one of those promising, novel stimulation forms characterized by subthreshold stimulation, delivering more pulses per second and a higher pulse density to the spinal cord than conventional SCS.

Objectives

The aim of DISCOVER is to gather evidence about the effectiveness, feasibility, and (possible) side effects of HD stimulation.

Methods

The prospective, non-interventional, multi-center, clinical study, DISCOVER, is currently restricted to Belgium where 19 neuromodulation centers were selected. Patient recruitment started in October 2016 and is expected to end in October 2017. Subjects included are (1) patients with insufficient pain relief from conventional SCS or (2) neurostimulation-naïve patients suited for SCS. Patients will be assessed 1 month, 3 months, and 12 months after conversion to HD-SCS settings. Each patient’s visit will include: a numerical rating scale (NRS), Oswestry disability index (ODI), Pittsburgh sleep quality index (PSQI), EQ-5D, a pain map, registration of SCS settings, and a list of used pain medication.

Conclusions

Although promising results have been reported, adequate registration of its effectiveness and (possible) side-effects remains an unmet need. Main results are expected in 2019.