Hardware-Related Complications of Deep Brain Stimulation: A Review of the Published Literature

Asymptomatic cable twisting in a patient with impending Twiddler syndrome detected during deep brain stimulation surgery for Parkinson's disease: A case report

Background

Deep brain stimulation (DBS) has consistently demonstrated high efficacy and safety in patients with Parkinson's disease. Twiddler's syndrome is a rare occurrence of hardware failure in patients undergoing neuromodulation. We report here a case of subclinical cable twisting jeopardizing Twiddler's syndrome in a patient with Parkinson's disease who underwent DBS surgery targeting the globus pallidus internus (GPI).

Case Description

A 70-year-old woman with a 7-year history of Parkinson's disease refractory to medication was referred to our department for treatment of involuntary movements of the left hand and leg. She underwent right GPI DBS implantation. Left GPI DBS implantation was subsequently planned to manage resting tremors that developed in the right leg after the first surgery at around one year after the first surgery. During a routine check-up before the second surgery, we incidentally detected Twiddler's syndrome. The patient showed no neurological deficits in the left extremities, the same as before right GPI DBS. We performed left GPI DBS concomitantly with the revision of the implantable pulse generator and extension wire.

Conclusion

Twiddler's syndrome is a rare complication of DBS. Subclinical risk of cable twisting jeopardizing Twiddler's syndrome is rarely detected without clinical indications of hardware failure. Neurosurgeons should be cognizant of and regularly monitor the implanted device in case serious complications occur.

Increased electrode impedance as an indicator for early detection of deep brain stimulation (DBS) hardware Infection: Clinical experience and in vitro study

BACKGROUND

When deep brain stimulation (DBS) infections are identified, they are often too advanced to treat without complete hardware removal. New objective markers to promptly identify DBS infections are needed. We present a patient with GPi (globus pallidus interna) DBS for dystonia, where the electrode impedance unexpectedly increased 3-months post-operatively, followed by serologic and hematologic markers of inflammation at 6-months, prompting explantation surgery. We recreated these conditions in a laboratory environment to analyze the pattern of changing of electrical impedance across the contacts of a DBS lead following Staphylococcus biofilm formation.

METHODS

A stainless-steel culture chamber containing 1 % brain heart infusion agar was used. A DBS electrode was dipped in peptone water containing a strain of S. aureus and subsequently introduced into the chamber. The apparatus was incubated at 37 °C for 6 days. Impedance was measured at 24hr intervals. A control experiment without S. Aureus inoculation was used to determine changes in impedance over a period of 6-days.

RESULTS

The mean monopolar impedance on day-1 was 751.8 ± 23.8 Ω and on day-3 was 1004.8 ± 68.7 Ω, a 33.7 % rise (p = 0.007). A faint biofilm formation could be seen around the DBS lead by day-2 and florid growth by day-3. After addition of the linezolid solution, a 15.9 % decrease in monopolar impedance was observed from day 3-6 (p = 0.003).

CONCLUSION

This study gives insight into impedance trends following a hardware infection in DBS. Increased impedance outside expected norms may be valuable for early prediction of infection. Furthermore, timely management using antibiotics might reduce the frequency of infection-related explant surgeries.

Stereotactic Staged Asymmetric Bilateral Radiofrequency Lesioning for Parkinson's Disease

INTRODUCTION

Parkinson's disease (PD) is one of the most common neurodegenerative progressive disorders. Despite the dominance of neurostimulation technology, stereotactic lesioning operations play a significant role in the treatment of PD. The aim of the study was to evaluate the effectiveness and safety of staged bilateral asymmetric radiofrequency (RF) stereotactic lesioning in a highly selected group of PD patients.

MATERIAL AND METHODS

A retrospective review of 418 consecutive patients undergoing stereotactic ablation for advanced PD at our institution revealed 28 patients who underwent staged asymmetric bilateral ablation. In this subset, after initial RF thalamotomy, contralateral pallidotomy was performed in 16 (57.1%) patients (group Vim-GPi), and contralateral lesion of the subthalamic nucleus (STN) was performed in 12 (32.9%) patients (group Vim-STN). The mean duration of disease before the first surgery was 9.9 ± 0.8 years. The mean interval between the two operations was 3.5 ± 0.4 years (range, 1-10 years); in the Vim-GPi group, it was 3.1 ± 0.4 years; and in the Vim-STN group, it was 4.3 ± 0.1 years. After the second operation, the long-term follow-up lasted from 1 to 8 years (mean 4.8 ± 0.5 years). All patients were evaluated 1 year after the second operation.

RESULTS

One year after staged bilateral lesioning, the mean tremor score improved from baseline, prior to the first operation, from 19.8 to 3.8 (improvement of 81%), the overall mean rigidity score improved from 11.0 to 3.7 (improvement of 66%), and hypokinesia improved from 14.8 to 8.9 (improvement of 40%). One year after staged bilateral lesioning, the total UPDRS score improved in the Vim-GPi group by 47% in the OFF and 45.9% in the ON states. In the Vim-STN group, the total UPDRS score improved from baseline, prior to the first operation, by 44.8% in the OFF and 51.6% in the ON states. Overall, levodopa dose was reduced by 43.4%. Neurological complications were observed in 4 (14.3%) cases; among them, 1 (3.6%) patient had permanent events related to local ischemia after pallidotomy.

CONCLUSION

Staged asymmetric bilateral stereotactic RF lesioning can be a safe and effective method in highly selected patients with advanced PD, particularly where deep brain stimulation is not available or desirable. Careful identification and selection of patients for ablative surgery allow achieving optimal results in the treatment of PD with bilateral symptoms.

Efficacy of Occipital Nerve Stimulation in Trigeminal Autonomic Cephalalgias: A Systematic Review

BACKGROUND

Trigeminal autonomic cephalalgias (TACs) are a group of highly disabling primary headache disorders. Although pharmacological treatments exist, they are not always effective or well tolerated. Occipital nerve stimulation (ONS) is a potentially effective surgical treatment.

OBJECTIVE

To perform a systematic review of the efficacy of ONS in treating TACs.

METHODS

A systematic review was performed using Medline, Embase, and Cochrane databases. Primary outcomes were reduction in headache intensity, duration, and frequency. Secondary outcomes included adverse event rate and reduction in medication use. Because of large differences in outcome measures, data for patients suffering from short-lasting, unilateral, and neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) and cranial autonomic symptoms (SUNA) were reported separately. Risk of bias was assessed using the NIH Quality Assessment Tools.

RESULTS

A total of 417 patients from 14 published papers were included in the analysis, of which 15 patients were in the SUNCT/SUNA cohort. The mean reduction in headache intensity and duration was 26.2% and 31.4%, respectively. There was a mean reduction in headache frequency of 50%, as well as a 61.2% reduction in the use of abortive medications and a 31.1% reduction in the use of prophylactic medications. In the SUNCT/SUNA cohort, the mean decrease in headache intensity and duration was 56.8% and 42.8%. The overall responder rate, defined as a >50% reduction in attack frequency, was 60.8% for the non-SUNCT/non-SUNA cohort and 66.7% for the SUNCT/SUNA cohort. Adverse events requiring repeat surgery were reported in 33% of cases. Risk of bias assessment suggests that articles included in this review had reasonable internal validity.

CONCLUSION

ONS may be an effective surgical treatment for approximately two thirds of patients with medically refractory TACs.

Essential Tremor - Deep Brain Stimulation vs. Focused Ultrasound

INTRODUCTION

Essential Tremor (ET) is one of the most common tremor syndromes typically presented as action tremor, affecting mainly the upper limbs. In at least 30-50% of patients, tremor interferes with quality of life, does not respond to first-line therapies and/or intolerable adverse effects may occur. Therefore, surgery may be considered.

AREAS COVERED

In this review, the authors discuss and compare unilateral ventral intermedius nucleus deep brain stimulation (VIM DBS) and bilateral DBS with Magnetic Resonance-guided Focused Ultrasound (MRgFUS) thalamotomy, which comprises focused acoustic energy generating ablation under real-time MRI guidance. Discussion includes their impact on tremor reduction and their potential complications. Finally, the authors provide their expert opinion.

EXPERT OPINION

DBS is adjustable, potentially reversible and allows bilateral treatments; however, it is invasive requires hardware implantation, and has higher surgical risks. Instead, MRgFUS is less invasive, less expensive, and requires no hardware maintenance. Beyond these technical differences, the decision should also involve the patient, family, and caregivers.

Focused ultrasound thalamotomy for tremor treatment impacts the cerebello-thalamo-cortical network

High-intensity Magnetic Resonance-guided Focused Ultrasound (MRgFUS) is a recent, non-invasive line of treatment for medication-resistant tremor. We used MRgFUS to produce small lesions in the thalamic ventral intermediate nucleus (VIM), an important node in the cerebello-thalamo-cortical tremor network, in 13 patients with tremor-dominant Parkinson's disease or essential tremor. Significant tremor alleviation in the target hand ensued (t(12) = 7.21, p < 0.001, two-tailed), which was strongly associated with the functional reorganization of the brain's hand region with the cerebellum (r = 0.91, p < 0.001, one-tailed). This reorganization potentially reflected a process of normalization, as there was a trend of increase in similarity between the hand cerebellar connectivity of the patients and that of a matched, healthy control group (n = 48) after treatment. Control regions in the ventral attention, dorsal attention, default, and frontoparietal networks, in comparison, exhibited no association with tremor alleviation and no normalization. More broadly, changes in functional connectivity were observed in regions belonging to the motor, limbic, visual, and dorsal attention networks, largely overlapping with regions connected to the lesion targets. Our results indicate that MRgFUS is a highly efficient treatment for tremor, and that lesioning the VIM may result in the reorganization of the cerebello-thalamo-cortical tremor network.

Neurotechnology for Pain

Neurotechnologies for treating pain rely on electrical stimulation of the central or peripheral nervous system to disrupt or block pain signaling and have been commercialized to treat a variety of pain conditions. While their adoption is accelerating, neurotechnologies are still frequently viewed as a last resort, after many other treatment options have been explored. We review the pain conditions commonly treated with electrical stimulation, as well as the specific neurotechnologies used for treating those conditions. We identify barriers to adoption, including a limited understanding of mechanisms of action, inconsistent efficacy across patients, and challenges related to selectivity of stimulation and off-target side effects. We describe design improvements that have recently been implemented, as well as some cutting-edge technologies that may address the limitations of existing neurotechnologies. Addressing these challenges will accelerate adoption and change neurotechnologies from last-line to first-line treatments for people living with chronic pain.

Complications of Deep Brain Stimulation for Parkinson Disease and Relationship between Micro-electrode tracks and hemorrhage: Systematic Review and Meta-Analysis

BACKGROUND

Deep brain stimulation is a common treatment for Parkinson's disease (PD). Despite strong efficacy in well-selected patients, complications can occur. Intraoperative micro-electrode recording (MER) can enhance efficacy by improving lead accuracy. However, there is controversy as to whether MER increases risk of hemorrhage.

OBJECTIVES

To provide a comprehensive systematic review and meta-analysis reporting complication rates from deep brain stimulation in PD. We also interrogate the association between hemorrhage and MER.

METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were implemented while querying the Pubmed, Embase, and Cochrane databases. All included studies were randomized controlled trials and prospective case series with 5 or more patients. Primary outcomes included rates of overall revision, infection, lead malposition, surgical site and wound complications, hardware-related complications, and seizure. The secondary outcome was the relationship between number of MER tracks and hemorrhage rate.

RESULTS

262 articles with 21,261 patients were included in the analysis. Mean follow-up was 25.8 months (range 0-133). Complication rates were: revision 4.9%, infection 4.2%, lead malposition 3.3%, surgical site complications 2.8%, hemorrhage 2.4%, hardware-related complications 2.4%, and seizure 1.9%. While hemorrhage rate did not increase with single-track MER (odds ratio, 3.49; P = 0.29), there was a significant non-linear increase with each additional track.

CONCLUSION

Infection and lead malposition were the most common complications. Hemorrhage risk increases with more than one MER track. These results highlight the challenge of balancing surgical accuracy and perioperative risk.

Translational aspects of deep brain stimulation for chronic pain

The use of deep brain stimulation (DBS) for the treatment of chronic pain was one of the first applications of this technique in functional neurosurgery. Established brain targets in the clinic include the periaqueductal (PAG)/periventricular gray matter (PVG) and sensory thalamic nuclei. More recently, the anterior cingulum (ACC) and the ventral striatum/anterior limb of the internal capsule (VS/ALIC) have been investigated for the treatment of emotional components of pain. In the clinic, most studies showed a response in 20%-70% of patients. In various applications of DBS, animal models either provided the rationale for the development of clinical trials or were utilized as a tool to study potential mechanisms of stimulation responses. Despite the complex nature of pain and the fact that animal models cannot reliably reflect the subjective nature of this condition, multiple preparations have emerged over the years. Overall, DBS was shown to produce an antinociceptive effect in rodents when delivered to targets known to induce analgesic effects in humans, suggesting a good predictive validity. Compared to the relatively high number of clinical trials in the field, however, the number of animal studies has been somewhat limited. Additional investigation using modern neuroscience techniques could unravel the mechanisms and neurocircuitry involved in the analgesic effects of DBS and help to optimize this therapy.

An antibiotic envelope to reduce infections in deep brain stimulation surgery

The therapeutic benefits of Deep Brain Stimulation (DBS) surgery in patients with movement disorderssuch as Parkinson's Diseaseare life-altering. Surgical site infections (SSI), however, can result in increasedhospitalisations, prolonged antibiotics and neurological sequelae. We performed aretrospective review to evaluate the effectiveness of an antibiotic envelope to reduce SSI in DBS surgeries.This study includedall DBS surgeries performed between August 2020 to May 2022 using a single-use, multifilament, antibiotic-coated mesh envelope wrapped around the DBS implantable pulse generator (IPG)(TYRX™ Absorbable Antibacterial Envelope,Medtronic Fridley, MN, USA). Standardised infection-prevention measures were applied and various patient-specific and surgery-specific factors were analysed.44 patients were analysed with 26 (59.1 %) primary implantations and 18 (40.9 %) revision surgeries.The median age was 65 years old with an average follow-up of 13.5 months (range 3-24 months). The mean Body Mass Indexwas 24.0 (range 16.7-35.6). 8 (18.2 %) patients had underlying diabetes mellitus. There were only 2 (4.5 %) SSIs reported with neither involvingthe subcutaneous IPG and antibiotic envelope. 1 superficial-incisional SSI (2.3 %) was from a prior retro-auricular abscess around a lead-wirerequiring antibiotics and subcutaneous implanttransposition. The other was a deep-incisional SSI (2.3 %) from repetitive trauma causingdelayed scalp wound dehiscence and lead-wire extrusion, requiring antibiotics and wound revision. Both subjects were discharged well with no implants removed. Theantibioticenvelope therefore appears to be a safe and well-tolerated adjunct that may reduce SSIs in DBS surgery. Further prospective work withlarger sample sizes in a multi-institution setting is required.

Deep Brain Stimulator Device Infection: The Mayo Clinic Rochester Experience

Background

Deep brain stimulator (DBS)-related infection is a recognized complication that may significantly alter the course of DBS therapy. We describe the Mayo Clinic Rochester experience with DBS-related infections.

Methods

This was a retrospective study of all adults (≥18 years old) who underwent DBS-related procedures between 2000 and 2020 at the Mayo Clinic Rochester.

Results

There were 1087 patients who underwent 1896 procedures. Infection occurred in 57/1112 (5%) primary DBS implantations and 16/784 (2%) revision surgeries. The median time to infection (interquartile range) was 2.1 (0.9-6.9) months. The odds of infection were higher with longer operative length (P = .002), higher body mass index (BMI; P = .006), male sex (P = .041), and diabetes mellitus (P = .002). The association between infection and higher BMI (P = .002), male sex (P = .016), and diabetes mellitus (P = .003) remained significant in a subgroup analysis of primary implantations but not revision surgeries. Infection was superficial in 17 (23%) and deep in 56 (77%) cases. Commonly identified pathogens were Staphylococcus aureus (65%), coagulase-negative staphylococci (43%), and Cutibacterium acnes (45%). Three device management approaches were identified: 39 (53%) had complete device explantation, 20 (27%) had surgical intervention with device retention, and 14 (19%) had medical management alone. Treatment failure occurred in 16 (23%) patients. Time-to-event analysis showed fewer treatment failures with complete device explantation (P = .015). Only 1 individual had complications with brain abscess at failure.

Conclusions

Primary DBS implantations had higher rates of infection compared with revision surgeries. Complete device explantation was favored for deep infections. However, device salvage was commonly attempted and is a reasonable approach in select cases given the low rate of complications.

Hardware-Related Skin Erosion in Deep Brain Stimulation for Parkinson's Disease: How Far Can We Go? An Illustrative Case Report

Skin erosion is a hardware-related complication commonly described after deep brain stimulation (DBS). Hardware exposure is often associated with the development of infection that can lead to implant removal. However, in selected cases, it is possible to manage skin erosion without having to remove the hardware. This article presents the case of a patient with recurrent skin erosions above the IPG, who underwent multiple surgeries. Given the failure of less invasive approaches, a more complex surgery with the employment of a pedunculated flap of pectoralis major in order to cover the IPG was attempted. Nevertheless, the IPG removal was finally unavoidable, resulting in a rapid decline in clinical performance. This illustrative case suggests how, in patients with sustained stimulation who benefit from a good degree of autonomy, it may be useful to use invasive surgical techniques to resolve skin erosions and save the DBS system. In spite of everything, sometimes complete or partial removal of the implant still becomes unavoidable, but this can lead to a severe worsening of PD symptoms. Definitive removal of the system should therefore be considered only in cases of frank infection or after failure of all other approaches.

Deep brain stimulation and spinal cord stimulation for orthostatic tremor: A systematic review

BACKGROUND

Orthostatic tremor is a rare and debilitating movement disorder. Its first-line treatment is pharmacological. For pharmaco-refractory patients, surgical treatment options such as deep brain stimulation (DBS) and spinal cord stimulation (SCS) have been investigated recently.

OBJECTIVES

We conducted a systematic review of all published outcome and safety data on DBS and SCS for orthostatic tremor patients.

METHODS

We searched Pubmed and Embase for studies describing orthostatic tremor patients treated with DBS or SCS. We collected all available outcome and safety data and our primary endpoint was the change in unsupported stance duration 1 year postoperatively (±6 months).

RESULTS

We included 15 studies, reporting on 32 orthostatic tremor patients who underwent DBS, 4 patients SCS and 2 both. The ventral intermediate nucleus and the zona incerta were targeted in 25/34 and 9/34 DBS cases, respectively. The median stance time at 1 year follow-up was 240 s compared to 30 s pre-operatively (p < 0.001). Stimulation-induced side effects occurred in the majority of patients, but were often transient. Bilateral stimulation appeared more effective than unilateral and stimulation settings were comparable to thalamic DBS for essential tremor. There were insufficient data available to draw meaningful conclusions on the long-term effects of DBS. Due to insufficient data, no conclusions could be drawn on the effects of SCS on orthostatic tremor.

CONCLUSION

DBS may be effective to increase stance time in orthostatic tremor patients in the first year, but further research is necessary to evaluate the long-term effects and the role of spinal cord stimulation.

Deep brain stimulation of the subthalamic nucleus for epilepsy

Deep brain stimulation of the subthalamic nucleus (STN-DBS) is a promising palliative option for patients with refractory epilepsy. However, crucial questions remain unanswered: Which patients are the optimal candidates? How, where, and when to stimulate the STN? And what is the mechanism of STN-DBS action on epilepsy? Thus, we reviewed the clinical evidence on the antiepileptic effects of STN-DBS and its possible mechanisms on drug-resistant epilepsy, its safety, and the factors influencing stimulation outcomes. This information may guide clinical decision-making. In addition, based on the current knowledge on the effect of STN-DBS on epilepsy, we suggest research that needs to be carried out in the future.

Development of Unilateral Peri-Lead Edema Into Large Cystic Cavitation After Deep Brain Stimulation: A Case Report

Background and Importance

Deep brain stimulation (DBS) has been approved to treat a variety of movement disorders, including Parkinson's disease (PD), essential tremor, and dystonia. Following the DBS surgery, some perioperative and even delayed complications due to intracranial and hardware-related events could occur, which may be life-threatening and require immediate remedial measures.

Clinical Presentation

We report a case of an older woman with advanced PD who developed the unique complication of unilateral cyst formation at the tip of the DBS electrode after undergoing bilateral placement of subthalamic nucleus DBS. After a period of controlled motor symptoms, the patient showed new neurological deficits related to right peri-lead edema. However, the new neurological symptoms regressed quickly over several days with stereotactic implantation of a puncture needle to drain the cyst fluid without removing the affected lead.

Conclusion

The occurrence of an intraparenchymal cyst following DBS surgery is a rare but life-threatening complication that could relate to edema around the electrodes or cerebrospinal fluid tracking. Stereotactic aspiration makes the intracranial cyst regress safely and effectively and ensures that the electrode is in the optimal position of the target nucleus to achieve an effective DBS surgery.

Effects of Transcranial Direct Current Stimulation on Cognitive and Affective Outcomes Using Virtual Stimuli: A Systematic Review

Transcranial direct current stimulation (tDCS) is a noninvasive form of brain stimulation used to influence neural activity. While early tDCS studies primarily used static stimuli, there is growing interest in dynamic stimulus presentations using virtual environments (VEs). This review attempts to convey the state of the field. This is not a quantitative meta-analysis as there are not yet enough studies following consistent protocols and/or reporting adequate data. In addition to reviewing the state of the literature, this review includes an exploratory analysis of the available data. Following preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines, studies were culled from several databases. Results from this review reveal differences between online and offline stimulation. While offline stimulation did not influence affective and cognitive outcomes, online stimulation led to small changes in affect and cognition. Future studies should include randomized controlled trials with larger samples. Furthermore, greater care needs to be applied to full data reporting (e.g., means, standard deviations, and data for their nonsignificant findings) to improve our understanding of the combined effects of virtual stimuli with tDCS.

A systematic review on neuromodulation therapies for reducing body weight in patients with obesity

The global prevalence of obesity increases yearly along with a rising demand for efficacious, safe, and accessible treatments. Neuromodulation interventions (i.e., deep brain stimulation [DBS], transcranial magnetic stimulation [TMS], transcranial direct current stimulation [tDCS], percutaneous neurostimulation [PENS], vagus nerve stimulation [VNS], and gastric electrical stimulation [GES]) have been proposed as novel therapies. This systematic review sought to examine the safety and efficacy of neuromodulation therapies in reducing body weight in patients with obesity. Using PRISMA guidelines, we performed a systematic review for studies on neuromodulation for the treatment of obesity, resulting in 60 trials included (7 DBS, 5 TMS, 7 tDCS, 17 PENS and VNS, and 24 GES; a total of 3,042 participants). While promising results have been reported in open label studies, double-blinded randomized clinical trials often did not reach their primary endpoints, with no technique inducing a striking reduction in body weight. Bearing in mind the complexity and multifactorial nature of obesity, it is possible that a single treatment may not be enough for patients to lose or maintain the weight lost at long term.

Prevention and Treatment of Hardware-Related Infections in Deep Brain Stimulation Surgeries: A Retrospective and Historical Controlled Study

Background

Hardware-related infection in deep brain stimulation (DBS) is one of the most commonly reported complications frequently resulting in the removal of implantable pulse generator (IPG).

Objective

The aim of this study was to establish a useful strategy to better prevent and treat those infections and to improve the preservation rates of IPG.

Methods

We conducted a retrospective and historical controlled study of all adult patients (≥18 years old) who had undergone initial DBS implantation at a single center. All participants were enrolled in the control group (between June 2005 and June 2014) or intervention group (between July 2014 and May 2019) based on their surgery dates. We used the intraoperative irrigation with hydrogen dioxide solution in the intervention group. Based on the dates of diagnosis, patients with hardware-related infection after DBS were enrolled in group A (between June 2005 and June 2014) or group B (between July 2014 and May 2019). IPG-sparing algorithm (Isa) was applied for group B. The early-onset IPG infections of the control and intervention groups were evaluated. The IPG preservation rates in both groups A and B were statistically analyzed.

Results

Six cases of early IPG infection and subsequent IPG removal occurred in the control group, while none occurred after intraoperative usage of the hydrogen dioxide in the intervention group. IPG preservation rate of infected cases in group B was significantly higher than that in group A (70% vs.16%, p = 0.004).

Conclusion

The combined application of hydrogen dioxide solution and Isa seems to be an effective strategy to prevent IPG infection.

Vacuum-Assisted Closure with Temporalis Muscle Reconstruction for Recurrent Scalp Erosion Following Deep Brain Stimulation: A Case Report

BACKGROUND

Scalp erosion is not an uncommon complication of deep brain stimulation (DBS) surgery. Although various methods have been proposed to prevent and manage complications, there are still challenges. We introduce a case of recurrent scalp erosion after DBS surgery treated with vacuum-assisted closure.

CASE DESCRIPTION

This article reports the case of a patient who underwent DBS for advanced Parkinson's disease and suffered from recurrent scalp erosion with device extrusion through the skin. Scalp erosion occurred 2 years after DBS and repeated improvement and deterioration despite scalp reconstruction using a skin flap. We opened the wound and performed temporal muscle reconstruction to cover the burr hole site, and we changed the exposed cable and applied vacuum-assisted closure. During the follow-up period, no signs of erosion or infection occurred, and DBS efficacy was preserved.

CONCLUSION

To date, the available management strategies for scalp erosion after DBS are revision with debridement and scalp reconstruction using skin flaps or skin grafts. However, if erosion occurs repeatedly despite the above management strategies, vacuum-assisted closure with temporalis muscle reconstruction could be a suitable option. We suggest that if the condition of the scalp is weakened, it is worth considering this approach preferentially.

Skin erosion in deep brain stimulation procedures: Using the temporalis muscle to treat this complication - A technical note

Background:

Skin erosion is a common complication after deep brain stimulator procedures. Despite being a relatively common event, there is no standard surgical technique or a widely accepted guideline for managing this kind of complication.

Methods:

We describe a case of cutaneous erosion in the connector’s site of deep brain stimulation case, surgically managed with anterior displacement of the connectors and overlapping and wrapping the connections within the temporal muscle.

Results:

Postoperatively, the patient did well and achieved complete resolution of the skin erosion, with no signs of infection or new skin lesions.

Conclusion:

This technique demonstrated to be effective in this case in the long-term follow-up.

Patient-Centered Identification of Meaningful Regulatory Endpoints for Medical Devices to Treat Parkinson's Disease

Introduction. A growing literature has developed on identifying outcomes that matter to patients. This study demonstrates an approach involving patient and regulatory perspectives to identify outcomes that are meaningful in the context of medical devices for Parkinson’s disease (PD). Methods. A systematic process was used for specifying relevant regulatory endpoints by synthesizing inputs of various sources and stakeholders. First, a literature review was conducted to identify important benefits, risks, and other considerations for medical devices to treat PD; patient discussion groups (n = 6) were conducted to refine the list of considerations, followed by a survey (n = 29) to prioritize them; and patient and Food and Drug Administration (FDA) reviewers informed specification of the final endpoints. Two FDA clinicians gave clinical and regulatory perspectives at each step. Results. Movement symptoms were ranked as most important (ranked 1 or 2 by 72% of participants) and psychological and cognitive symptoms as the next most important (ranked 1 or 2 by 52% of participants). Within movement symptoms, falls, impaired movement, bradykinesia, resting tremor, stiffness, and rigidity were ranked highly. Overall, nine attributes were identified and prioritized as patient-centric for use in clinical trial design and quantitative patient preference studies. These attributes were benefits and risks related to therapeutics for PD as well as other considerations, including time until a medical device is available for patient use. Discussion. This prospective approach identified meaningful and relevant benefits, risks, and other considerations that may be used for clinical trial design and quantitative patient preference studies. Although PD was the focus of this study, the approach can be used to study patient perspectives about other disease or treatment areas.

Neuromodulation Approaches in Parkinson's Disease Using Deep Brain Stimulation and Transcranial Magnetic Stimulation

Parkinson's Disease (PD) is the second most common neurodegenerative disease, characterized by progressive motor (such as resting tremor, hypokinesia, postural instability) and non-motor symptoms (such as neuropsychiatric decline and autonomic dysfunction). Since its introduction in the late 1980s, deep brain stimulation (DBS) has revolutionized the treatment of PD. Initially used in patients' with advanced PD with either medically refractory motor symptoms or medication intolerance, DBS typically provides excellent improvement in motor symptoms. Indications for DBS have continued to expand, with demonstrated efficacy in early PD and essential tremor, and promising preliminary results in the treatment of epilepsy, psychiatric disease, and depression. Advancements in DBS hardware, programming, neuroimaging, and surgical techniques have led to progressive improvement in efficacy and safety profiles. Thanks to ongoing research into remote programming, adaptive DBS, new targets, and alternative interventions, such as transcranial magnetic stimulation, the opportunities for further improvements in DBS and neuromodulation are bright.

Significance of MRI Guided Focused Ultrasound Thalamotomy for Parkinson's Disease: A Review

BACKGROUND

Magnetic-Resonance guided Focused Ultrasound (FUS) thalamotomy is a new and less invasive surgical technique for treating Parkinson's disease (PD). During therapy, the required part of the cerebral (as STN, Internal Globus Pallidus, and Ventral Intermediate Nucleus) is ablated with less possibility of infection and brain hemorrhage as it normally happens in invasive procedures.

INTRODUCTION

New advancement in the technique enables it for transcranial transportation of US. Nowadays, US coupling with MRI confirms the accurate energy transferring and monitoring. So, MRI guided FUS lesioning is discovered for various psychiatric and brain disorders.

METHODS

A technical overview of non-invasive MRI-FUS thalamotomy to treat various tremors is described here. Research, review articles, and book chapters are extracted from online resources using related search strings from the year 1994-2020.

RESULTS

MRgFUS is concluded a non-invasive, satisfactory, and safe technique to reduce the tremor. Conlusion: MRgFUS is comparatively a new method that is being explored as a non-invasive cerebral ablation to solve the problems of movement disorder.

Toward living neuroprosthetics: developing a biological brain pacemaker as a living neuromodulatory implant for improving parkinsonian symptoms

Objective.Therapeutic intervention for Parkinson's disease (PD) via deep brain stimulation (DBS) represents the current paradigm for managing the advanced stages of the disease in patients when treatment with pharmaceuticals becomes inadequate. Although DBS is the prevailing therapy in these cases, the overall effectiveness and reliability of DBS can be diminished over time due to hardware complications and biocompatibility issues with the electronic implants. To achieve a lifetime solution, we envision that the next generation of neural implants will be entirely 'biological' and 'autologous', both physically and functionally. Thus, in this study, we set forth toward developing a biological brain pacemaker for treating PD. Our focus is to investigate engineering strategies for creating a multicellular biological circuit that integrates innate biological design and function while incorporating principles of neuromodulation to create a biological mechanism for delivering high-frequency stimulation with cellular specificity.Approach.We engineer a 3D multicellular circuit design built entirely from biological and biocompatible components using established tissue engineering protocols to demonstrate the feasibility of creating a living neural implant. Furthermore, using 2D co-culture systems, we investigate the physiologically relevant parameters that would be necessary to further develop a therapeutic benefit of high-frequency stimulation with cellular specificity within our construct design.Main results.Our results demonstrate the feasibility of fabricating a 3D multicellular circuit device in an implantable form. Furthermore, we show we can organize cellular materials to create potential functional connections in normal physiological conditions, thus laying down the foundation of designing a high-frequency pacing system for selective and controlled therapeutic neurostimulation.Significance.The findings from this study may lead to the future development of autologous living neural implants that both circumvent the issues inherent in electronic neural implants and form more biocompatible devices with lifelong robustness to repair and restore motor functions, with the ultimate benefit for patients with PD.

Movement during focused ultrasound therapy caused by an unstable magnetic resonance table: case report

Transcranial MR-guided focused ultrasound (MRgFUS) therapy is a less invasive form of stereotactic treatment for tremors and other movement disorders. Its stereotactic accuracy is ensured by stability of the stereotactic frame and MR table. The authors report a case wherein the patient's movement was detected, and the MR images were repeated to continue the treatment. A 72-year-old man with essential tremor underwent unilateral ventralis intermedius thalamotomy using MRgFUS. The stereotactic frame was correctly fixed to the patient's skull and the table. During the seventh sonication, the patient pressed the emergency button and vomited several times. Before the eighth sonication, the patient's movement was detected and was verified on coronal images. The MR images were repeated, and the treatment was successfully completed with significant improvement in the tremors. After treatment, it was discovered that the MR table was laterally unstable due to the absence of ball bearings, which should be present on both sides of the guide rail of the MR table. The ball bearings were attached to the reverse side of the table, and the table was stabilized. Stereotactic accuracy of MRgFUS is not only ensured by rigid fixation of the stereotactic frame, but also by stability of the MR table.

Neuromodulation for chronic pain

Neuromodulation is an expanding area of pain medicine that incorporates an array of non-invasive, minimally invasive, and surgical electrical therapies. In this Series paper, we focus on spinal cord stimulation (SCS) therapies discussed within the framework of other invasive, minimally invasive, and non-invasive neuromodulation therapies. These therapies include deep brain and motor cortex stimulation, peripheral nerve stimulation, and the non-invasive treatments of repetitive transcranial magnetic stimulation, transcranial direct current stimulation, and transcutaneous electrical nerve stimulation. SCS methods with electrical variables that differ from traditional SCS have been approved. Although methods devoid of paraesthesias (eg, high frequency) should theoretically allow for placebo-controlled trials, few have been done. There is low-to-moderate quality evidence that SCS is superior to reoperation or conventional medical management for failed back surgery syndrome, and conflicting evidence as to the superiority of traditional SCS over sham stimulation or between different SCS modalities. Peripheral nerve stimulation technologies have also undergone rapid development and become less invasive, including many that are placed percutaneously. There is low-to-moderate quality evidence that peripheral nerve stimulation is effective for neuropathic pain in an extremity, low quality evidence that it is effective for back pain with or without leg pain, and conflicting evidence that it can prevent migraines. In the USA and many areas in Europe, deep brain and motor cortex stimulation are not approved for chronic pain, but are used off-label for refractory cases. Overall, there is mixed evidence supporting brain stimulation, with most sham-controlled trials yielding negative findings. Regarding non-invasive modalities, there is moderate quality evidence that repetitive transcranial magnetic stimulation does not provide meaningful benefit for chronic pain in general, but conflicting evidence regarding pain relief for neuropathic pain and headaches. For transcranial direct current stimulation, there is low-quality evidence supporting its benefit for chronic pain, but conflicting evidence regarding a small treatment effect for neuropathic pain and headaches. For transcutaneous electrical nerve stimulation, there is low-quality evidence that it is superior to sham or no treatment for neuropathic pain, but conflicting evidence for non-neuropathic pain. Future research should focus on better evaluating the short-term and long-term effectiveness of all neuromodulation modalities and whether they decrease health-care use, and on refining selection criteria and treatment variables.

Deep Brain Electrode Externalization and Risk of Infection: A Systematic Review and Meta-Analysis

BACKGROUND

When evaluating deep brain stimulation (DBS) for newer indications, patients may benefit from trial stimulation prior to permanent implantation or for investigatory purposes. Although several case series have evaluated infectious complications among DBS patients who underwent trials with external hardware, outcomes have been inconsistent.

OBJECTIVE

To determine whether a period of lead externalization is associated with an increased risk of infection.

METHODS

We conducted a Preferred Reporting Items for Systematic Reviews and Meta-Analyses compliant systematic review of all studies that included rates of infection for patients who were externalized prior to DBS implantation. A meta-analysis of proportions was performed to estimate the pooled proportion of infection across studies, and a meta-analysis of relative risks was conducted on those studies that included a control group of nonexternalized patients. Heterogeneity across studies was assessed via I2 index.

RESULTS

Our search retrieved 23 articles, comprising 1354 patients who underwent lead externalization. The pooled proportion of infection was 6.9% (95% CI: 4.7%-9.5%), with a moderate to high level of heterogeneity between studies (I2 = 62.2%; 95% CI: 40.7-75.9; P < .0001). A total of 3 studies, comprising 212 externalized patients, included a control group. Rate of infection in externalized patients was 5.2% as compared to 6.0% in nonexternalized patients. However, meta-analysis was inadequately powered to determine whether there was indeed no difference in infection rate between the groups.

CONCLUSION

The rate of infection in patients with electrode externalization is comparable to that reported in the literature for DBS implantation without a trial period. Future studies are needed before this information can be confidently used in the clinical setting.

Postoperative Externalization of Deep Brain Stimulation Leads Does Not Increase Infection Risk

OBJECTIVES

Externalization of deep brain stimulation (DBS) leads is performed to allow electrophysiological recording from implanted electrodes as well as assessment of clinical response to trial stimulation before implantable pulse generator (IPG) insertion. Hypothetically, lead externalization provides a route for inoculation and subsequent infection of hardware, though this has not been established definitively in the literature. We sought to determine if lead externalization affects the risk of infection in DBS surgery.

MATERIALS AND METHODS

We present our center's experience of lead externalization and surgical site infection (SSI) in DBS surgery for movement disorders. Patients were divided into two cohorts: one in which leads were not externalized and IPGs were implanted at the time of electrode insertion, and one in which leads were externalized for six days while patients underwent electrophysiological recording from DBS electrodes for research. We compare baseline characteristics of these two cohorts and their SSI rates.

RESULTS

Infective complications were experienced by 3/82 (3.7%) patients overall with one (1.2%) requiring complete hardware removal. These occurred in 1/36 (2.7%) in the externalized cohort and 2/46 (4.3%) in the nonexternalized cohort. The incidence of infection between the two cohorts was not significantly different (p = 1, two-tailed Fisher's exact test). This lack of significant difference persisted when baseline variation between the cohorts in age, hardware manufacturer, and indication for DBS were corrected by excluding patients implanted for dystonia, none of whom underwent externalization. We present and discuss in detail each of the three cases of infection.

CONCLUSIONS

Our data suggest that externalization of leads does not increase the risk of infective complications in DBS surgery. Lead externalization is a safe procedure which can provide a substrate for unique neurophysiological studies to advance knowledge and therapy of disorders treated with DBS.

Risk Factors for Wire Fracture or Tethering in Deep Brain Stimulation: A 15-Year Experience

BACKGROUND

In deep brain stimulation (DBS), tunneled lead and extension wires connect the implantable pulse generator to the subcortical electrode, but circuit discontinuity and wire revision compromise a significant portion of treatments.

OBJECTIVE

To identify factors predisposing to fracture or tethering of the lead or extension wire in patients undergoing DBS.

METHOD

Retrospective review of wire-related complications was performed in a consecutive series of patients treated with DBS at a tertiary academic medical center over 15 yr.

RESULTS

A total of 275 patients had 513 extension wires implanted or revised. There were 258 extensions of 40 cm implanted with a postauricular connector (50.3%), 229 extensions of 60 cm with a parietal connector (44.6%), and 26 extensions 40 cm with a parietal connector (5.1%). In total, 26 lead or extension wires (5.1%) were replaced for fracture. Fracture rates for 60 cm extensions with a parietal connector, 40 cm wires with a postauricular connector, and 40 cm extensions with a parietal connector were 0.2, 1.4, and 12.9 fractures per 100 wire-years, significantly different on log-rank test. Total 16 (89%) 40 cm extension wires with a postauricular connector had fracture implicating the lead wire. Tethering occurred only in patients with 60 cm extensions with parietal connectors (1.14 tetherings per 100 wire-years). Reoperation rate correlated with younger age, dystonia, and target in the GPI.

CONCLUSION

The 40 cm extensions with parietal connectors have the highest fracture risk and should be avoided. Postauricular connectors risk lead wire fracture and should be employed cautiously. The 60 cm parietal wires may reduce fracture risk but increase tethering risk.

A Systematic Review of Deep Brain Stimulation Targets for Obsessive Compulsive Disorder

BACKGROUND

Obsessive compulsive disorder (OCD) is a complex neuropsychiatric disease characterized by obsessions and compulsions. Deep brain stimulation (DBS) has demonstrated efficacy in improving symptoms in medically refractory patients. Multiple targets have been investigated.

OBJECTIVE

To systematically review the current level and quality of evidence supporting OCD-DBS by target region with the goal of establishing a common nomenclature.

METHODS

A systematic literature review was performed using the PubMed database and a patient/problem, intervention, comparison, outcome search with the terms "DBS" and "OCD." Of 86 eligible articles that underwent full-text review, 28 were included for review. Articles were excluded if the target was not specified, the focus on nonclinical outcomes, the follow-up period shorter than 3 mo, or the sample size smaller than 3 subjects. Level of evidence was assigned according to the American Association of Neurological Surgeons/Congress of Neurological Surgeons joint guideline committee recommendations. Quality of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation approach.

RESULTS

Selected publications included 9 randomized controlled trials, 1 cohort study, 1 case-control study, 1 cross-sectional study, and 16 case series. Striatal region targets such as the anterior limb of the internal capsule, ventral capsule/ventral striatum, and nucleus accumbens were identified, but stereotactic coordinates were similar despite differing structural names. Only 15 of 28 articles included coordinates.

CONCLUSION

The striatal area is the most commonly targeted region for OCD-DBS. We recommend a common nomenclature based on this review. To move the field forward to individualized therapy, active contact location relative to stereotactic coordinates and patient specific anatomical and clinical variances need to be reported.

Neuronal Activity and Synaptic Plasticity in a Reimplanted STN-DBS Patient with Parkinson's Disease: Recordings from Two Surgeries

The authors report the case of an elderly male in his 60s who, after 5 months of efficacious treatment with chronic deep brain stimulation of the subthalamic nucleus (STN-DBS), developed a hardware-related erosion necessitating removal of the complete DBS system. One and a half years following the first implantation, a new STN-DBS system was implanted along an immediately adjacent trajectory, and reproduction of clinical efficacy was reported. Additionally, 2 microstimulation protocols were compared between the 2 surgeries, i.e., one to assess the stimulation frequency response of STN neurons and another to assess inhibitory synaptic plasticity in the substantia nigra pars reticulata (SNr). The spontaneous neuronal firing rates of STN neurons in each hemisphere were also compared between the 2 surgeries. The results suggest that the frequency-sensitivity of STN neurons may have been reduced (i.e., more resistant to neuronal suppression), while the spontaneous baseline firing rates of STN neurons and the plasticity measured in the SNr remained unchanged (2 factors that may be indicative of neurodegenerative processes).

An initial experience with intraoperative O-Arm for deep brain stimulation surgery: can it replace post-operative MRI?

Deep brain stimulation (DBS) is used to treat movement disorders, severe psychiatric disorders, and neuropathic pain, among other diseases. Advanced neuroimaging techniques allow direct or indirect localization of the target site, which is verified in many centers by the intraoperative recording of unitary neuronal activity. Intraoperative image acquisition technology (e.g., O-Arm) is increasingly used for accurate electrode positioning throughout the surgery. The aim of our study is to analyze the initial experience of our team in the utilization of O-Arm for planning DBS and monitoring its precision and accuracy throughout the procedure. The study included 13 patients with movement disorders. All underwent DBS with the intraoperative O-arm image acquisition system (iCT) and Medtronic StealthStation S7 cranial planning system, placing a total of 25 electrodes. For each patient, we calculated the difference between real and theoretic x, y, z coordinates, using the paired Student's t test to evaluate absolute and directional differences and the one-sample Student's t test to analyze differences in Euclidean distances. No statistically significant differences were found in absolute, directional, or Euclidean distances between intended and actual x, y, and z coordinates, based on iCT scan. Our experience confirms that utilization of the O-Arm system in DBS provides accurate and precise verification of electrode placements throughout the procedure. Recent studies found no significant differences between iCT and postoperative MRI, the current gold standard. Further prospective studies are warranted to test the elimination of postoperative MRI when this system is used.

Repeat magnetic resonance imaging-guided focused ultrasound thalamotomy for recurrent essential tremor: case report and review of MRI findings

An 86-year-old right-handed man with medically refractory essential tremor was treated using left-sided MRI-guided focused ultrasound (MRgFUS) thalamotomy targeting the dentatorubrothalamic tract (DRTT) at its intersection with the ventral intermediate nucleus of the thalamus, with immediate symptomatic improvement and immediate postprocedure imaging demonstrating disruption of the DRTT. The patient experienced a partial return of symptoms 9 weeks following the procedure, and MRI demonstrated retraction of the left thalamic ablation site. The patient underwent repeat left-sided MRgFUS thalamotomy 4 months after initial treatment, resulting in reduced tremor. MR thermometry temperature measurements during the second MRgFUS procedure were unreliable with large fluctuations and false readings, likely due to susceptibility effects from the initial MRgFUS procedure. Final sonications were therefore monitored using the amount of energy delivered. The patient fared well after the second procedure and had sustained improvement in tremor control at the 12-month follow-up. This is the first report to describe the technical challenges of repeat MRgFUS with serial imaging.

Cerebrospinal Fluid Leak to the IPG Subcutaneous Pocket after Deep Brain Stimulation Implantation: A Case Report

This case report presents a 54-year-old Parkinson´s disease patient who underwent a DBS implantation to the subthalamic nuclei bilaterally. Shortly after the operation, the subcutaneous pocket of the generator filled with a liquid. Repeated aspirations did not show any bacterial contamination, and an infection was not found. In the sample, a beta-trace protein was detected that proved the presence of cerebrospinal fluid. A lumbar drain was immediately placed, and a chest compression bandage was fastened for 7 days. After removing the lumbar drain and the compression bandage, no additional liquid was observed, and the wound healed without any other complication. We present an unusual adverse event related to DBS surgery and suggest an effective treatment that has led to uncomplicated healing.

Safety and efficacy of magnetic resonance imaging-guided focused ultrasound neurosurgery for Parkinson's disease: a systematic review

Magnetic resonance imaging-guided focused ultrasound (MRgFUS) neurosurgery is a new option for medication-resistant Parkinson's disease (PD), but its safety and efficacy remain elusive. This study aimed to investigate the safety and efficacy of MRgFUS for PD by systematically reviewing related literature. PubMed and EMBASE were searched to identify related studies. Inclusion criteria were (1) reported the efficacy or safety of MRgFUS for PD and (2) published in English. Exclusion criteria were (1) nonhuman study, (2) review or meta-analysis or other literature types without original data, and (3) conference abstract without full text. Data on study characteristics, treatment parameters, efficacy, and adverse events were collected. Descriptive synthesis of data was performed. Eleven studies containing 80 patients were included. Nine studies were observational studies with no controls. Two studies included a randomized and controlled phase. Most studies included tremor-dominant PD. Ten studies reported decline of UPDRS-III scores after MRgFUS, and five reported a statistically significant decline. Nine studies evaluated the quality of life (QOL). Significant improvement of QOL was reported by four studies using the 39-item Parkinson's disease questionnaire. Four studies investigated the impact of MRgFUS on non-motor symptoms. Most tests indicated that MRgFUS had no significant effect on neuropsychological outcomes. Most adverse events were mild and transient. MRgFUS is a potential treatment for PD with satisfying efficacy and safety. Studies in this field are still limited. More studies with strict design, larger sample size, and longer follow-up are needed to further investigate its efficacy and safety for PD.

Open-loop deep brain stimulation for the treatment of epilepsy: a systematic review of clinical outcomes over the past decade (2008-present)

OBJECTIVE The field of deep brain stimulation (DBS) for epilepsy has grown tremendously since its inception in the 1970s and 1980s. The goal of this review is to identify and evaluate all studies published on the topic of open-loop DBS for epilepsy over the past decade (2008 to present). METHODS A PubMed search was conducted to identify all articles reporting clinical outcomes of open-loop DBS for the treatment of epilepsy published since January 1, 2008. The following composite search terms were used: ("epilepsy" [MeSH] OR "seizures" [MeSH] OR "kindling, neurologic" [MeSH] OR epilep* OR seizure* OR convuls*) AND ("deep brain stimulation" [MeSH] OR "deep brain stimulation" OR "DBS") OR ("electric stimulation therapy" [MeSH] OR "electric stimulation therapy" OR "implantable neurostimulators" [MeSH]). RESULTS The authors identified 41 studies that met the criteria for inclusion. The anterior nucleus of the thalamus, centromedian nucleus of the thalamus, and hippocampus were the most frequently evaluated targets. Among the 41 articles, 19 reported on stimulation of the anterior nucleus of the thalamus, 6 evaluated stimulation of the centromedian nucleus of the thalamus, and 9 evaluated stimulation of the hippocampus. The remaining 7 articles reported on the evaluation of alternative DBS targets, including the posterior hypothalamus, subthalamic nucleus, ventral intermediate nucleus of the thalamus, nucleus accumbens, caudal zone incerta, mammillothalamic tract, and fornix. The authors evaluated each study for overall epilepsy response rates as well as adverse events and other significant, nonepilepsy outcomes. CONCLUSIONS Level I evidence supports the safety and efficacy of stimulating the anterior nucleus of the thalamus and the hippocampus for the treatment of medically refractory epilepsy. Level III and IV evidence supports stimulation of other targets for epilepsy. Ongoing research into the efficacy, adverse effects, and mechanisms of open-loop DBS continues to expand the knowledge supporting the use of these treatment modalities in patients with refractory epilepsy.

Detection of bacterial DNA on neurostimulation systems in patients without overt infection

OBJECTIVE

Hardware-related infection remains a major problem in patients with neurostimulation systems. The role of bacterial colonization and the formation of biofilm on the surface of implanted devices remain unclear. Here, we analysed the incidence of bacterial DNA on the surface of implantable pulse generators (IPGs) using 16S rRNA gene sequencing in a consecutive series of patients who underwent routine IPG replacement without clinical signs of infection.

PATIENTS AND METHODS

We included 36 patients who underwent scheduled replacement surgery of 44 IPGs. The removed IPGs were processed and whole genomic DNA was extracted. The detection of bacterial DNA was carried out by Polymerase Chain Reaction (PCR) using universal bacterial primers targeting the 16S rRNA gene. The DNA strands were analysed by single-strand conformation polymorphism (SSCP) analysis.

RESULTS

Indications for chronic neurostimulation were Parkinson disease, tremor, dystonia, neuropathic pain and peripheral artery occlusion disease. Mean age of patients at the time of implantation was 48 ± 17.6 years. The mean interval between implantation and replacement of the IPG was 24.8 months. PCR/SSCP detected bacterial DNA of various species in 5/36 patients (13.9%) and in 5/44 pacemakers (11.4%), respectively. There was no evidence of clinical infection or wound healing impairment during follow-up time of 45.6 ± 19.6 months.

CONCLUSION

Bacterial DNA can be detected on the surface of IPGs of neurostimulation systems in patients without clinical signs of infection by using PCR techniques. It remains unclear, similar to other permanently implanted devices, which mechanisms and processes promote progression to the point of overt infection.

Safety and accuracy of incisionless transcranial MR-guided focused ultrasound functional neurosurgery: single-center experience with 253 targets in 180 treatments

OBJECTIVE

Since the first clinical application of the incisionless magnetic resonance-guided focused ultrasound (MRgFUS) technology only small series of patients have been reported, and thus only extrapolations of the procedure-related risks could be offered. In this study, the authors analyze side-effects and targeting accuracy in 180 consecutive treatments with MRgFUS for chronic therapy-resistant idiopathic Parkinson's disease (PD), essential tremor (ET), cerebellar tremor (CT), and neuropathic pain (NP), all performed in their dedicated center.

METHODS

A total of 180 treatments with MRgFUS for chronic therapy-resistant idiopathic PD, ET, CT, and NP were prospectively assessed for side-effects and targeting accuracy. Monitoring for later side-effects was continued for at least 3 months after the procedure in all but 1 case (0.6%); in that single case, the patient was lost to follow-up after an uneventful early postoperative course. The surgical targets were the pallidothalamic tract (pallidothalamic tractotomy, n = 105), the cerebellothalamic tract (cerebellothalamic tractotomy, n = 50), the central lateral nucleus (central lateral thalamotomy, n = 84), the centrum medianum (centrum medianum thalamotomy, n = 12), and the globus pallidus (pallidotomy, n = 2). Cognitive testing was performed before, 1-2 days after, and 1 year after the procedure. The Mini-Mental State Examination (MMSE) was used for the first 29 cases and was then replaced by the Montreal Cognitive Assessment (MoCA). Lesion reconstruction and measurement of targeting accuracy were done on 2-day posttreatment MR images for each performed target. To determine targeting accuracy measurement, 234 out of the 253 lesions depicted in the 2-day postoperative MR examination could be 3D-reconstructed.

RESULTS

The mean MoCA score was slightly improved 2 days postoperatively (p = 0.002) and remained stable at 1-year follow-up (p = 0.03). The mean MMSE score was also slightly improved 2 days postoperatively and at 1-year follow-up, but the improvement was not statistically significant (p = 0.06 and p = 0.2, respectively). The mean (± SD) accuracy was 0.32 ± 0.29 mm, 0.29 ± 0.28 mm, and 0.44 ± 0.39 mm for the mediolateral, anteroposterior, and dorsoventral dimensions, respectively. The mean 3D accuracy was 0.73 ± 0.39 mm. As to side-effects, 14 events over 180 treatments were documented. They were classified into procedure-related (n = 4, 2.2%), effect on neighboring structures (n = 3, 1.7%), and disease-related (n = 7, 3.9%). There was no bleeding.

CONCLUSIONS

The incisionless transcranial MRgFUS technology demonstrates a higher targeting accuracy and a lower side-effect profile than techniques requiring cerebral penetration. In the absence of penetration brain shift, this technique avoids the placement of a thermolesion away from the chosen target, thus suppressing the need for reversible therapeutic energy application. With the use of proper physiopathology-based targets, definitive therapeutic effects can be coupled with sparing of sensory, motor, and paralimbic/multimodal thalamocortical functions. Clinical efficacy, not analyzed in this investigation, will ultimately rest in proper target selection and optimized thermolesional coverage of the target.

Neuromodulation Strategies in Post-Traumatic Stress Disorder: From Preclinical Models to Clinical Applications

Post-traumatic stress disorder (PTSD) is an often debilitating disease with a lifetime prevalence rate between 5⁻8%. In war veterans, these numbers are even higher, reaching approximately 10% to 25%. Although most patients benefit from the use of medications and psychotherapy, approximately 20% to 30% do not have an adequate response to conventional treatments. Neuromodulation strategies have been investigated for various psychiatric disorders with promising results, and may represent an important treatment option for individuals with difficult-to-treat forms of PTSD. We review the relevant neurocircuitry and preclinical stimulation studies in models of fear and anxiety, as well as clinical data on the use of transcranial direct current stimulation (tDCS), repetitive transcranial magnetic stimulation (rTMS), and deep brain stimulation (DBS) for the treatment of PTSD.

Deep brain stimulation hardware-related infections: 10-year experience at a single institution

OBJECTIVE

Deep brain stimulation is an effective surgical treatment for managing some neurological and psychiatric disorders. Infection related to the deep brain stimulator (DBS) hardware causes significant morbidity: hardware explantation may be required; initial disease symptoms such as tremor, rigidity, and bradykinesia may recur; and the medication requirements for adequate disease management may increase. These morbidities are of particular concern given that published DBS-related infection rates have been as high as 23%. To date, however, the key risk factors for and the potential preventive measures against these infections remain largely uncharacterized. In this study, the authors endeavored to identify possible risk factors for DBS-related infection and analyze the efficacy of prophylactic intrawound vancomycin powder (VP).

METHODS

The authors performed a retrospective cohort study of patients who had undergone primary DBS implantation at a single institution in the period from December 2005 through September 2015 to identify possible risk factors for surgical site infection (SSI) and to assess the impact of perioperative (before, during, and after surgery) prophylactic antibiotics on the SSI rate. They also evaluated the effect of a change in the National Healthcare Safety Network's definition of SSI on the number of infections detected. Statistical analyses were performed using the 2-sample t-test, the Wilcoxon rank-sum test, the chi-square test, Fisher's exact test, or logistic regression, as appropriate for the variables examined.

RESULTS

Four hundred sixty-four electrodes were placed in 242 adults during 245 primary procedures over approximately 10.5 years; most patients underwent bilateral electrode implantation. Among the 245 procedures, 9 SSIs (3.7%) occurred within 90 days and 16 (6.5%) occurred within 1 year of DBS placement. Gram-positive bacteria were the most common etiological agents. Most patient- and procedure-related characteristics did not differ between those who had acquired an SSI and those who had not. The rate of SSIs among patients who had received intrawound VP was only 3.3% compared with 9.7% among those who had not received topical VP (OR 0.32, 95% CI 0.10-1.02, p = 0.04). After controlling for patient sex, the association between VP and decreased SSI risk did not reach the predetermined level of significance (adjusted OR 0.32, 95% CI 0.10-1.03, p = 0.06). The SSI rates were similar after staged and unstaged implantations.

CONCLUSIONS

While most patient-related and procedure-related factors assessed in this study were not associated with the risk for an SSI, the data did suggest that intrawound VP may help to reduce the SSI risk after DBS implantation. Furthermore, given the implications of SSI after DBS surgery and the frequency of infections occurring more than 90 days after implantation, continued follow-up for at least 1 year after such a procedure is prudent to establish the true burden of these infections and to properly treat them when they do occur.

Neurologic Medical Device Overview for Pathologists

Thorough morphologic evaluations of medical devices placed in or near the nervous system depend on many factors. Pathologists interpreting a neurologic device study must be familiar with the regulatory framework affecting device development, biocompatibility and safety determinants impacting nervous tissue responses, and appropriate study design, including the use of appropriate animal models, group design, device localization, euthanasia time points, tissue examination, sampling and processing, histochemistry and immunohistochemistry, and reporting. This overview contextualizes these features of neurologic medical devices for pathologists engaged in device evaluations.

Initial Results of Bilateral Subthalamic Nucleus Stimulation for Parkinson Disease in a Newly Established Center in a Developing Country: Shiraz, Southern Iran

OBJECTIVE

To report the establishment of a new center for deep brain stimulation (DBS) as a surgical treatment for Parkinson disease and the surgical outcomes, from 2014 to 2017 in Shiraz, Southern Iran.

METHODS

A new treatment program was established in Shiraz through a multidisciplinary team in 2014. Thirty-four patients underwent implantation of subthalamic nucleus (STN) electrodes during the last 3 years. Twenty-five patients fulfilled the minimum 6-month follow-up criteria. The baseline Unified Parkinson Disease Rating Scale (UPDRS) was assessed 1 month before surgery in both off-medication and on-medication states by a movement disorder neurologist. To evaluate the outcomes, subscores of the UPDRS were assessed in all patients before surgery and at least 6 months after the operation.

RESULTS

All 25 patients had advanced Parkinson disease categorized as stage 3 or 4 using the Hoehn and Yahr scale. STN DBS resulted in a dramatic improvement in motor function of most patients. A reduction in dopaminergic medication dosage (average 60% reduction) was observed. The mean improvement was 40% in UPDRS II and 67% in UPDRS III. No surgical or hardware complications were observed. Stimulation-related adverse effects, including increased falling and worsening of speech, occurred in a few patients after surgery. Most of the patients experienced weight gain after surgery.

CONCLUSIONS

Bilateral STN DBS is a satisfactory and safe treatment for carefully selected patients with advanced Parkinson disease. According to the results, the procedure can be performed safely and with comparable results in developing countries around the world.

Deep Brain Stimulation in Moroccan Patients With Parkinson's Disease: The Experience of Neurology Department of Rabat

Introduction: Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is known as a therapy of choice of advanced Parkinson's disease. The present study aimed to assess the beneficial and side effects of STN DBS in Moroccan Parkinsonian patients. Material and Methods: Thirty five patients underwent bilateral STN DBS from 2008 to 2016 in the Rabat University Hospital. Patients were assessed preoperatively and followed up for 6 to 12 months using the Unified Parkinson's Disease Rating Scale in four conditions (stimulation OFF and ON and medication OFF and ON), the levodopa-equivalent daily dose (LEDD), dyskinesia and fluctuation scores and PDQ39 scale for quality of life (QOL). Postoperative side effects were also recorded. Results: The mean age at disease onset was 42.31 ± 7.29 years [28-58] and the mean age at surgery was 54.66 ± 8.51 years [34-70]. The median disease duration was 11.95 ± 4.28 years [5-22]. Sixty-three percentage of patients were male. 11.4% of patients were tremor dominant while 45.71 showed akinetic-rigid form and 42.90 were classified as mixed phenotype. The LEDD before surgery was 1200 mg/day [800-1500]. All patients had motor fluctuations whereas non-motor fluctuations were present in 61.80% of cases. STN DBS decreased the LEDD by 51.72%, as the mean LEDD post-surgery was 450 [188-800]. The UPDRS-III was improved by 52.27%, dyskinesia score by 66.70% and motor fluctuations by 50%, whereas QOL improved by 27.12%. Post-operative side effects were hypophonia (2 cases), infection (3 cases), and pneumocephalus (2 cases). Conclusion: Our results showed that STN DBS is an effective treatment in Moroccan Parkinsonian patients leading to a major improvement of the most disabling symptoms (dyskinesia, motor fluctuation) and a better QOL.