Delayed complications of deep brain stimulation: 16-year experience in 249 patients

Decreased brain volume may be associated with the occurrence of peri-lead edema in Parkinson's disease patients with deep brain stimulation

BACKGROUND

Peri-lead edema (PLE) is a poorly understood complication of deep brain stimulation (DBS), which has been described in patients presenting occasionally with profound and often delayed symptoms with an incidence ranging from 0.4% up to even 100%. Therefore, our study aims to investigate the association of brain and brain compartment volumes on magnetic resonance imaging (MRI) with the occurrence of PLE in Parkinson's disease (PD) patients after DBS implantation in subthalamic nuclei (STN).

METHODS

This retrospective study included 125 consecutive PD patients who underwent STN DBS at the Department of Neurosurgery, Dubrava University Hospital from 2010 to 2022. Qualitative analysis was done on postoperative MRI T2-weighted sequence by two independent observers, marking PLE on midbrain, thalamus, and subcortical levels as mild, moderate, or severe. Quantitative volumetric analysis of brain and brain compartment volumes was conducted using an automated CIVET processing pipeline on preoperative MRI T1 MPRAGE sequences. In addition, observed PLE on individual hemispheres was delineated manually and measured using Analyze 14.0 software.

RESULTS

In our cohort, PLE was observed in 32.17%, mostly bilaterally. Mild PLE was observed in the majority of patients, regardless of the level observed. Age, sex, diabetes, hypertension, vascular disease, and the use of anticoagulant/antiplatelet therapy showed no significant association with the occurrence of PLE. Total grey matter volume showed a significant association with the PLE occurrence (r = -0.22, p = 0.04), as well as cortex volume (r = -0.32, p = 0.0005). Cortical volumes of hemispheres, overall hemisphere volumes, as well as hemisphere/total intracranial volume ratio showed significant association with the PLE occurrence. Furthermore, the volume of the cortex and total grey volume represent moderate indicators, while hemisphere volumes, cortical volumes of hemispheres, and hemisphere/total intracranial volume ratio represent mild to moderate indicators of possible PLE occurrence.

CONCLUSION

The results of our study suggest that the morphometric MRI measurements, as a useful tool, can provide relevant information about the structural status of the brain in patients with PD and represent moderate indicators of possible PLE occurrence. Identifying patients with greater brain atrophy, especially regarding grey matter before DBS implantation, will allow us to estimate the possible postoperative symptoms and intervene in a timely manner. Further studies are needed to confirm our findings and to investigate other potential predictors and risk factors of PLE occurrence.

Postoperative use of steroids for peri-electrode edema after deep brain stimulation surgery: A retrospective cohort study

BACKGROUND

To review the incidence and extent of peri-electrode edema after DBS and to clarify the effect of postoperative use of steroids on the peri-electrode edema.

METHODS

This retrospective cohort study included 250 patients who underwent bilateral subthalamic nucleus (STN) DBS surgery with intact MRI within 1 month after DBS surgery. Patients were divided into steroid and non-steroid groups, based on postoperative steroids use. The occurrence and extent of peri-electrode edema were compared between the two groups, and other associated factors were analyzed using univariate and multivariate methods.

RESULTS

Peri-electrode edema >1 cm3 in at least one hemisphere was reported in 215 (86.00%) patients. The mean volume of peri-electrode edema observed in the steroid group was significantly smaller than in the non-steroid group (8.09 ± 8.47 cm3 vs 17.10 ± 16.90 cm3 , p < 0.001). In the steroid group, 104 (32.91%) of the 316 implanted electrodes present with edema less than 1 cm3 , whereas in the non-steroid group, only 27 (14.67%) of the 184 implanted electrodes present with edema less than 1 cm3 (p < 0.001). Multivariate analysis indicated that lesser peri-electrode edema was significantly associated with postoperative steroids use and general anesthesia.

CONCLUSIONS

Peri-electrode edema is common after DBS surgery, and postoperative steroids use reduces the occurrence and extent of peri-electrode edema.

Rescuing Infected Deep Brain Stimulation Therapies in Severely Affected Patients

(1) Background: Infections in deep brain stimulation (DBS) hardware, while an undesired complication of DBS surgeries, can be effectively addressed. Minor infections are typically treated with wound revision and IV antibiotics. However, when visible hardware infection occurs, most centers opt for complete removal, leaving the patient in a preoperative state and necessitating post-removal care. To avoid the need for such care, a novel technique was developed. (2) Methods: The electrodes are placed at the exact same spot and then led to the contralateral side. new extensions and a new generator contralateral to the infection as well. Subsequently, the infected system is removed. This case series includes six patients. (3) Results: The average duration of DBS system implantation before the second surgery was 272 days. Only one system had to be removed after 18 months due to reoccurring infection; the others remained unaffected. Laboratory alterations and pathogens were identified in only half of the patients. (4) Conclusions: The described surgical technique proves to be safe, well tolerated, and serves as a viable alternative to complete system removal. Importantly, it effectively prevents the need of post-removal care for patients.

Incidence and management of idiopathic peri-lead edema (IPLE) following deep brain stimulation (DBS) surgery: Case series and review of the literature

OBJECTIVE

Idiopathic peri-lead edema (IPLE) is being increasingly described as a potential complication occurring after DBS surgery. Its incidence and relationship to post-operative symptoms, though, are still poorly defined and its understanding and management yet limited.

METHODS

We reviewed delayed (≥ 72 h) post-operative CT imaging of patients who underwent DBS surgery at our Institution. A comparison of clinical and laboratory findings was carried out between patients with IPLE and controls.

RESULTS

61 patients, accounting for 115 electrodes, were included. Incidence of IPLE was 37.7 % per patient and 29.5 % per electrode. Patients with IPLE were significantly older than controls (52.82 ± 15.65 years vs 44.73 ± 18.82 years, p = 0.04). There was no difference in incidence of new-onset neurological symptoms between patients with IPLE and controls. Longer operative time (180.65 ± 34.30 min vs 158.34 ± 49.28 min, p = 0.06) and a greater number of MERs per electrode were associated with IPLE (3.37 ± 1.21 vs 3.00 ± 1.63, p = 0.089), though these comparisons did not meet the statistical significance. None of the patients with IPLE underwent hardware removal, with IPLE vanishing spontaneously over months.

CONCLUSIONS

IPLE is an underestimated, benign event that may occur after DBS surgery. Age, longer operative time and MER use may represent risk factors for IPLE formation, but further studies are needed. The presence of post-operative neurological symptoms and fever was not associated with IPLE presence, highlighting its benign nature and suggesting that empiric treatment may not be always justified.

Cerebrospinal Fluid Leakage to the Chest Subcutaneous Pocket Due to Aggressive Brain Edema around the Leads for Deep Brain Stimulation: A Case Report and Literature Review

Cerebral edema around the lead has been reported as a complication of deep brain stimulation; however, the causes remain unknown. Herein, we present a rare case of sudden cerebral edema around the lead occurring after deep brain stimulation. This was accompanied by cerebrospinal fluid (CSF) leakage into the subcutaneous thoracic pocket around the implantable pulse generator in a 53-year-old man with Parkinson's disease. No such case has been reported thus far. Lumbar drainage was performed to improve CSF leakage. The cerebral edema initially responded to steroids, but then it stopped responding to treatment. The edema appeared alternately on the left and right sides, and cyst formation was noted around the left lead. There are some reports of cyst formation around the lead; however, in our case, images were used to monitor the edema and cyst from their appearance to their disappearance. Our data suggest that cyst formation and cerebral edema are related.

Peri-lead edema and local field potential correlation in post-surgery subthalamic nucleus deep brain stimulation patients

Implanting deep brain stimulation (DBS) electrodes in patients with Parkinson’s disease often results in the appearance of a non-infectious, delayed-onset edema that disappears over time. However, the time window between the DBS electrode and DBS stimulating device implant is often used to record local field potentials (LFPs) which are used both to better understand basal ganglia pathophysiology and to improve DBS therapy. In this work, we investigated whether the presence of post-surgery edema correlates with the quality of LFP recordings in eight patients with advanced Parkinson’s disease implanted with subthalamic DBS electrodes. The magnetic resonance scans of the brain after 8.5 ± 1.5 days from the implantation surgery were segmented and the peri-electrode edema volume was calculated for both brain hemispheres. We found a correlation (ρ = −0.81, p < 0.0218, Spearman’s correlation coefficient) between left side local field potentials of the low beta band (11–20 Hz) and the edema volume of the same side. No other significant differences between the hemispheres were found. Despite the limited sample size, our results suggest that the effect on LFPs may be related to the edema localization, thus indicating a mechanism involving brain networks instead of a simple change in the electrode-tissue interface.

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.

Survey-based identification of design requirements and constraints for a wearable tremor suppression device

Introduction

Parkinsonian tremor has severely impacted the lives of 65% of individuals with Parkinson’s disease, and nearly 25% do not respond to traditional treatments. Although wearable tremor suppression devices (WTSDs) have become a promising alternative approach, this technology is still in the early stages of development, and no studies have reported the stakeholders’ opinions on this technology and their desired design requirements.

Methods

An online survey was distributed to affected Canadians and Canadian movement disorder specialists (MDS) to acquire information on demographics, the current state of treatments, opinions on the WTSDs, and the desired design requirements of future WTSDs.

Results

A total of 101 affected individuals and 24 MDS completed the survey. It was found that both groups are generally open to using WTSDs to manage tremor. The most important design requirement to end users is the adaptability to lifestyle, followed by weight and size, accurate motion, comfort, safety, quick response, and cost. Lastly, most of the participants (65%) think that the device should cost under $500.

Conclusions

The findings from this study can be used as guidelines for the development of future WTSDs, such that the future generations could be evaluated and accepted by the end users.

Piezoelectric ultrasound energy-harvesting device for deep brain stimulation and analgesia applications

Supplying wireless power is a challenging technical problem of great importance for implantable biomedical devices. Here, we introduce a novel implantable piezoelectric ultrasound energy-harvesting device based on Sm-doped Pb(Mg_1/3Nb_2/3)O₃-PbTiO₃ (Sm-PMN-PT) single crystal. The output power density of this device can reach up to 1.1 W/cm² in vitro, which is 18 times higher than the previous record (60 mW/cm²). After being implanted in the rat brain, under 1-MHz ultrasound with a safe intensity of 212 mW/cm², the as-developed device can produce an instantaneous effective output power of 280 μW, which can immediately activate the periaqueductal gray brain area. The rat electrophysiological experiments under anesthesia and behavioral experiments demonstrate that our wireless-powered device is well qualified for deep brain stimulation and analgesia applications. These encouraging results provide new insights into the development of implantable devices in the future.

Fulminant non-infectious peri-electrode edema after deep brain stimulation system implantation in a pediatric patient

Non-infectious peri-electrode edema is a rare complication after implantation of a deep brain stimulation (DBS) electrode. DBS is frequently used in the management of movement disorders with increasing interest surrounding its value in more rare disorders associated with movement abnormalities. This is the report of a 10-year-old male with Cockayne syndrome who acutely developed symptomatic non-infectious, non-hemorrhagic peri-electrode edema 18 days postoperatively from implantation of a DBS system targeting the bilateral globus pallidus internus. CT head confirmed extensive vasogenic edema along the entire length of the left electrode, and infectious workup was negative. The patient required admission to the pediatric intensive care unit for management utilizing steroid, hypertonic, and hyperosmolar therapy due to the amount of mass effect. Symptoms reduced over a 7-day hospital stay and were completely resolved at 1 month without removal of the DBS system. Management of this rare entity remains controversial and often involves the use of steroids and anti-epileptic prophylaxis. This represents the first case of non-infectious peri-electrode edema reported in a pediatric patient and is especially notable for its fulminant nature.

The need to be alert to complications of peri‐lead cerebral edema caused by deep brain stimulation implantation: A systematic literature review and meta‐analysis study

Background

The compatibility of deep brain stimulation (DBS) hardware and MRI scans has greatly improved the diagnostic rate of postoperative peri‐lead edema (PLE). However, the etiology, incidence, and prognostic outcomes of this complication have not been established.

Objective

The incidence of PLE and associated symptoms, the process of occurrence and progression of this complication, as well as treatment strategies were evaluated.

Methods

We conducted a Preferred Reporting Items for Systematic Reviews and Meta‐Analyses compliant systematic review of all studies that reported on incidences of PLE and associated symptoms after DBS implantation. Through systematic literature review, we evaluated its causes, neuropsychiatric symptoms, duration, treatment methods, and prognostic outcomes.

Results

Our search retrieved 10 articles, including 5 articles on PLE and 10 articles on symptomatic PLE. The incidence of PLE was 35.8% (95% CI: 17.0%–54.6%), while the incidence of symptomatic PLE was 3.1% (95% CI: 1.5%–4.7%) accounting for 8.7% of PLE.

Conclusions

This complication is not as rare as previously reported. Therefore, it requires significant attention after DBS implantation. The correlation between its causes, duration, symptoms, and the area involved in edema should be assessed in long‐term prospective clinical studies with large sample sizes.

Driving restrictions following deep brain stimulation surgery

Background

There are currently no Australian guidelines to assist clinicians performing deep brain stimulation (DBS) procedures in setting postoperative driving restrictions.

Purpose

We aimed to provide recommendations for post-DBS driving restrictions to guide practice in Australia.

Methods

A review of current Australian and international driving guidelines, literature regarding the adverse effects of DBS and literature regarding the long-term effect of neurostimulation on driving was conducted using Elton B Stephens Company discovery service-linked databases. Australian neurologists and neurosurgeons who perform DBS were surveyed to gain insight into existing practice.

Results

No guidance on driving restrictions following DBS surgery was found, either in existing driving guidelines or in the literature. There was a wide difference seen in the rates of reported adverse effects from DBS surgery. The most serious adverse events (haemorrhage, seizure and neurological dysfunction) were uncommon. Longer term, there does not appear to be any adverse effect of DBS on driving ability. Survey of Australian practitioners revealed a universal acceptance of the need for and use of driving restrictions after DBS but significant heterogeneity in how return to driving is managed.

Conclusion

We propose a 6-week driving restriction for private licences and 6-month driving restriction for commercial licences in uncomplicated DBS. We also highlight some of the potential pitfalls and pearls to assist clinicians to modify these recommendations where needed. Ultimately, we hope this will stimulate further examination of this issue in research and by regulatory bodies to provide more robust direction for practitioners performing DBS implantation.

Deep Brain Stimulation Complications in Patients With Parkinson's Disease and Surgical Modifications: A Single-Center Retrospective Analysis

Background

As a complication-prone operation, deep brain stimulation (DBS) has become the first-line surgical approach for patients with advanced Parkinson’s disease (PD). This study aimed to evaluate the incidence and risk factors of DBS-associated complications.

Methods

We have reviewed a consecutive series of patients with PD undergoing DBS procedures to describe the type, severity, management, and outcome of postoperative complications from January 2011 to December 2018. Both univariate and multivariate analyses were performed to identify statistically significant risk factors. We also described our surgical strategies to minimize the adverse events.

Results

A total of 225 patients underwent 229 DBS implantation procedures (440 electrodes), of whom 20 patients experienced 23 DBS-associated complications, including ten operation-related complications and 13 hardware-related ones. Univariate analysis elucidated that comorbid medical conditions (P = 0.024), hypertension (P = 0.003), early-stage operation (P < 0.001), and unilateral electrode implantation (P = 0.029) as risk factors for overall complications, or more specifically, operation-related complications demonstrated in the stratified analysis. In contrast, no risk factor for hardware-related complications was identified. Statistical significances of hypertension (OR = 3.33, 95% CI: 1.14–9.71, P = 0.027) and early-stage (OR = 11.04, 95% CI: 2.42–50.45, P = 0.002) were further validated via multivariate analysis. As the annual number of DBS procedures increased, the incidence of complications gradually decreased (R = −0.699, P < 0.01). Additionally, there was a strong correlation between surgical complications and unplanned readmission (R = 0.730, P < 0.01).

Conclusion

The importance of cumulative experience and relevant technique modifications should be addressed to prevent DBS-associated complications and unplanned readmission.

Lesser-Known Aspects of Deep Brain Stimulation for Parkinson's Disease: Programming Sessions, Hardware Surgeries, Residential Care Admissions, and Deaths

OBJECTIVE

The long-term treatment burden, duration of community living, and survival of patients with Parkinson's disease (PD) after deep brain stimulation (DBS) implantation are unclear. This study aims to determine the frequency of programming, repeat hardware surgeries (of the intracranial electrode, implantable pulse generator [IPG], and extension-cable), and the timings of residential care and death in patients with PD treated with DBS.

MATERIALS AND METHODS

In this cross-sectional, population-based study, individual-level data were collected from the Australian government covering a 15-year period (2002-2016) on 1849 patients with PD followed from DBS implantation.

RESULTS

The mean DBS implantation age was 62.6 years and mean follow-up 5.0 years. Mean annual programming rates were 6.9 in the first year and 2.8 in subsequent years. 51.4% of patients required repeat hardware surgery. 11.3% of patients had repeat intracranial electrode surgery (including an overall 1.1% of patients who were completely explanted). 47.6% of patients had repeat IPG/extension-cable surgery including for presumed battery depletion. 6.2% of patients had early repeat IPG/extension-cable surgery (within one year of any previous such surgery). Thirty-day postoperative mortality was 0.3% after initial DBS implantation and 0.6% after any repeat hardware surgery. 25.3% of patients were admitted into residential care and 17.4% died. The median interval to residential care and death was 10.2 years and 11.4 years, respectively. Age more than 65 years was associated with fewer repeat hardware surgeries for presumed complications (any repeat surgery of electrodes, extension-cables, and early IPG surgery) and greater rates of residential care admission and death.

CONCLUSIONS

Data from a large cohort of patients with PD treated with DBS found that the median life span after surgery is ten years. Repeat hardware surgery, including of the intracranial electrodes, is common. These findings support development of technologies to reduce therapy burden such as enhanced surgical navigation, hardware miniaturization, and improved battery efficiency.

Deep Brain Stimulation-Related Surgical Site Infections: A Systematic Review and Meta-Analysis

BACKGROUND

Over the last decades, the increased use of deep brain stimulation (DBS) has raised concerns about the potential adverse health effects of the treatment. Surgical site infections (SSIs) following an elective surgery remain a major challenge for neurosurgeons. Few studies have examined the prevalence and risk factors of DBS-related complications, particularly focusing on SSIs.

OBJECTIVES

We systematically searched published literature, up to June 2020, with no language restrictions.

MATERIALS AND METHODS

Eligible were studies that examined the prevalence of DBS-related SSIs, as well as studies that examined risk and preventive factors in relation to SSIs. We extracted information on study characteristics, follow-up, exposure and outcome assessment, effect estimate and sample size. Summary odds ratios (sOR) and 95% confidence intervals (CI) were calculated from random-effects meta-analyses; heterogeneity and small-study effects were also assessed.

RESULTS

We identified 66 eligible studies that included 12,258 participants from 27 countries. The summary prevalence of SSIs was estimated at 5.0% (95% CI: 4.0%-6.0%) with higher rates for dystonia (6.5%), as well as for newer indications of DBS, such as epilepsy (9.5%), Tourette syndrome (5.9%) and OCD (4.5%). Similar prevalence rates were found between early-onset and late-onset hardware infections. Among risk and preventive factors, the perioperative implementation of intra-wound vancomycin was associated with statistically significantly lower risk of SSIs (sOR: 0.26, 95% CI: 0.09-0.74). Heterogeneity was nonsignificant in most meta-analyses.

CONCLUSION

The present study confirms the still high prevalence of SSIs, especially for newer indications of DBS and provides evidence that preventive measures, such as the implementation of topical vancomycin, seem promising in reducing the risk of DBS-related SSIs. Large clinical trials are needed to confirm the efficacy and safety of such measures.

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.

Recommendations for Deep Brain Stimulation Device Management During a Pandemic

Most medical centers are postponing elective procedures and deferring non-urgent clinic visits to conserve hospital resources and prevent spread of COVID-19. The pandemic crisis presents some unique challenges for patients currently being treated with deep brain stimulation (DBS). Movement disorder (Parkinson’s disease, essential tremor, dystonia), neuropsychiatric disorder (obsessive compulsive disorder, Tourette syndrome, depression), and epilepsy patients can develop varying degrees of symptom worsening from interruption of therapy due to neurostimulator battery reaching end of life, device malfunction or infection. Urgent intervention to maintain or restore stimulation may be required for patients with Parkinson’s disease who can develop a rare but potentially life-threatening complication known as DBS-withdrawal syndrome. Similarly, patients with generalized dystonia can develop status dystonicus, patients with obsessive compulsive disorder can become suicidal, and epilepsy patients can experience potentially life-threatening worsening of seizures as a result of therapy cessation. DBS system infection can require urgent, and rarely emergent surgery. Elective interventions including new implantations and initial programming should be postponed. For patients with existing DBS systems, the battery status and electrical integrity interrogation can now be performed using patient programmers, and employed through telemedicine visits or by phone consultations. The decision for replacement of the implantable pulse generator to prevent interruption of DBS therapy should be made on a case-by-case basis taking into consideration battery status and a patient’s tolerance to potential therapy disruption. Scheduling of the procedures, however, depends heavily on the hospital system regulations and on triage procedures with respect to safety and resource utilization during the health crisis.

Incidence and risk factors for seizures associated with deep brain stimulation surgery

OBJECTIVE

The objective of this study was to determine the incidence of seizures following deep brain stimulation (DBS) electrode implantation and to evaluate factors associated with postoperative seizures.

METHODS

The authors performed a single-center retrospective case-control study. The outcome of interest was seizure associated with DBS implantation. Univariate analyses were performed using the Student t-test for parametric continuous outcomes. The authors used the Kruskal-Wallis test or Wilcoxon rank-sum test for nonparametric continuous outcomes, chi-square statistics for categorical outcomes, and multivariate logistic regression for binomial variables.

RESULTS

A total of 814 DBS electrode implantations were performed in 645 patients (478 [58.7%] in men and 520 [63.9%] in patients with Parkinson's disease). In total, 22 (3.4%) patients who had undergone 23 (2.8%) placements experienced seizure. Of the 23 DBS implantation-related seizures, 21 were new-onset seizures (3.3% of 645 patients) and 2 were recurrence or worsening of a prior seizure disorder. Among the 23 cases with postimplantation-related seizure, epilepsy developed in 4 (17.4%) postoperatively; the risk of DBS-associated epilepsy was 0.50% per DBS electrode placement and 0.63% per patient. Nine (39.1%) implantation-related seizures had associated postoperative radiographic abnormalities. Multivariate analyses suggested that age at surgery conferred a modest increased risk for postoperative seizures (OR 1.06, 95% CI 1.02-1.10). Sex, primary diagnosis, electrode location and sidedness, and the number of trajectories were not significantly associated with seizures after DBS surgery.

CONCLUSIONS

Seizures associated with DBS electrode placement are uncommon, typically occur early within the postoperative period, and seldom lead to epilepsy. This study suggests that patient characteristics, such as age, may play a greater role than perioperative variables in determining seizure risk. Multiinstitutional studies may help better define and mitigate the risk of seizures after DBS surgery.

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.

Automated neurosurgical stereotactic planning for intraoperative use: a comprehensive review of the literature and perspectives

The creation of intracranial stereotactic trajectories, from entry point to target point, is still mostly done manually by the neurosurgeon. The development of automated stereotactic planning tools has been described in the literature. This systematic review aims to assess the effectiveness of stereotactic planning procedure automation and develop tools for patients undergoing neurosurgical stereotactic procedures. PubMed/MEDLINE, EMBASE, Google Scholar, CINAHL, PsycINFO, and Cochrane Register of Controlled Trials databases were searched from inception to September 1, 2019, at the exception of Google Scholar (from 1 January 2010 to September 1, 2019) in French and English. Eligible studies included all studies proposing automated stereotactic planning. A total of 1543 studies were screened. Forty-two studies were included in the systematic review, including 18 (42.9%) conference papers. The surgical procedures planned automatically were mainly deep brain stimulation (n = 14, 33.3%), stereoelectroencephalography (n = 12, 28.6%), and not specified (n = 10, 23.8%). The most frequently used surgical constraints to plan the trajectory were blood vessels (n = 32, 76.2%), cerebral sulci (n = 27, 64.3%), and cerebral ventricles (n = 23, 54.8%). The distance from blood vessels ranged from 1.96 to 4.78 mm for manual trajectories and from 2.47 to 7.0 mm for automated trajectories. At least one neurosurgeon was involved in 36 studies (85.7%). The automated stereotactic trajectory was preferred in 75.4% of the studied cases (range 30-92.9). Only 3 (7.1%) studies were multicentric. No study reported prospective use of the planning software. Stereotactic planning automation is a promising tool to provide valuable stereotactic trajectories for clinical applications.

High resolution transcranial acoustoelectric imaging of current densities from a directional deep brain stimulator

OBJECTIVE

New innovations in deep brain stimulation (DBS) enable directional current steering-allowing more precise electrical stimulation of the targeted brain structures for Parkinson's disease, essential tremor and other neurological disorders. While intra-operative navigation through MRI or CT approaches millimeter accuracy for placing the DBS leads, no existing modality provides feedback of the currents as they spread from the contacts through the brain tissue. In this study, we investigate transcranial acoustoelectric imaging (tAEI) as a new modality to non-invasively image and characterize current produced from a directional DBS lead. tAEI uses ultrasound (US) to modulate tissue resistivity to generate detectable voltage signals proportional to the local currents.

APPROACH

An 8-channel directional DBS lead (Infinity 6172ANS, Abbott Inc) was inserted inside three adult human skulls submerged in 0.9% NaCl. A 2.5 MHz linear array delivered US pulses through the transtemporal window and focused near the contacts on the lead, while a custom amplifier and acquisition system recorded the acoustoelectric (AE) interaction used to generate images.

MAIN RESULTS

tAEI detected monopolar current with stimulation pulses as short as 100 µs with an SNR ranging from 10-27 dB when using safe US pressure (mechanical indices  <0.78) and injected current of ~2 mA peak amplitude. Adjacent contacts were discernable along the length and within each ring of the lead with a mean radial separation between contacts of 2.10 and 1.34 mm, respectively.

SIGNIFICANCE

These results demonstrate the feasibility of tAEI for high resolution mapping of directional DBS currents using clinically-relevant stimulation parameters. This new modality may improve the accuracy for placing the DBS leads, guide calibration and programming, and monitor long-term performance of DBS for treatment of Parkinson's disease.

Reduced long-term cost and increased patient satisfaction with rechargeable implantable pulse generators for deep brain stimulation

OBJECTIVE

Deep brain stimulation (DBS) has revolutionized the treatment of neurological disease, but its therapeutic efficacy is limited by the lifetime of the implantable pulse generator (IPG) batteries. At the end of the battery life, IPG replacement surgery is required. New IPGs with rechargeable batteries (RC-IPGs) have recently been introduced and allow for decreased reoperation rates for IPG replacements. The authors aimed to examine the merits and limitations of these devices.

METHODS

The authors reviewed the medical records of patients who underwent DBS implantation at their institution. RC-IPGs were placed either during initial DBS implantation or during an IPG change. A cost analysis was performed that compared RC-IPGs with standard IPGs, and telephone patient surveys were conducted to assess patient satisfaction.

RESULTS

The authors identified 206 consecutive patients from 2011 to 2016 who underwent RC-IPG placement (mean age 61 years; 67 women, 33%). Parkinson's disease was the most common indication for DBS (n = 144, 70%), followed by essential tremor (n = 41, 20%), dystonia (n = 13, 6%), depression (n = 5, 2%), multiple sclerosis tremor (n = 2, 1%), and epilepsy (n = 1, 0.5%). DBS leads were typically placed bilaterally (n = 192, 93%) and targeted the subthalamic nucleus (n = 136, 66%), ventral intermediate nucleus of the thalamus (n = 43, 21%), internal globus pallidus (n = 21, 10%), ventral striatum (n = 5, 2%), or anterior nucleus of the thalamus (n = 1, 0.5%). RC-IPGs were inserted at initial DBS implantation in 123 patients (60%), while 83 patients (40%) were converted to RC-IPGs during an IPG replacement surgery. The authors found that RC-IPG implantation resulted in $60,900 of cost savings over the course of 9 years. Furthermore, patient satisfaction was high with RC-IPG implantation. Overall, 87.3% of patients who responded to the survey were satisfied with their device, and only 6.7% found the rechargeable component difficult to use. In patients who were switched from a standard IPG to RC-IPG, the majority who responded (70.3%) preferred the rechargeable IPG.

CONCLUSIONS

RC-IPGs can provide DBS patients with long-term therapeutic benefit while minimizing the need for battery replacement surgery. The authors have implanted rechargeable stimulators in 206 patients undergoing DBS surgery, and here they demonstrate the cost-effectiveness and high patient satisfaction associated with this procedure.

Long-term outcomes following deep brain stimulation for Parkinson's disease

OBJECTIVE

Deep brain stimulation (DBS) is an effective treatment for several movement disorders, including Parkinson's disease (PD). While this treatment has been available for decades, studies on long-term patient outcomes have been limited. Here, the authors examined survival and long-term outcomes of PD patients treated with DBS.

METHODS

The authors conducted a retrospective analysis using medical records of their patients to identify the first 400 consecutive patients who underwent DBS implantation at their institution from 1999 to 2007. The medical record was used to obtain baseline demographics and neurological status. The authors performed survival analyses using Kaplan-Meier estimation and multivariate regression using Cox proportional hazards modeling. Telephone surveys were used to determine long-term outcomes.

RESULTS

Demographics for the cohort of patients with PD (n = 320) were as follows: mean age of 61 years, 70% male, 27% of patients had at least 1 medical comorbidity (coronary artery disease, congestive heart failure, diabetes mellitus, atrial fibrillation, or deep vein thrombosis). Kaplan-Meier survival analysis on a subset of patients with at least 10 years of follow-up (n = 200) revealed a survival probability of 51% (mean age at death 73 years). Using multivariate regression, the authors found that age at implantation (HR 1.02, p = 0.01) and male sex (HR 1.42, p = 0.02) were predictive of reduced survival. Number of medical comorbidities was not significantly associated with survival (p > 0.5). Telephone surveys were completed by 40 surviving patients (mean age 55.1 ± 6.4 years, 72.5% male, 95% subthalamic nucleus DBS, mean follow-up 13.0 ± 1.7 years). Tremor responded best to DBS (72.5% of patients improved), while other motor symptoms remained stable. Ability to conduct activities of daily living (ADLs) remained stable (dressing, 78% of patients; running errands, 52.5% of patients) or worsened (preparing meals, 50% of patients). Patient satisfaction, however, remained high (92.5% happy with DBS, 95% would recommend DBS, and 75% felt it provided symptom control).

CONCLUSIONS

DBS for PD is associated with a 10-year survival rate of 51%. Survey data suggest that while DBS does not halt disease progression in PD, it provides durable symptomatic relief and allows many individuals to maintain ADLs over long-term follow-up greater than 10 years. Furthermore, patient satisfaction with DBS remains high at long-term follow-up.

Continuous subcutaneous apomorphine in advanced Parkinson's disease patients treated with deep brain stimulation

INTRODUCTION

Deep brain stimulation (DBS) is an effective therapy for patients with advanced Parkinson's disease (PD). However, sometimes, it is not sufficient to adequately control motor symptoms. We describe our experience with continuous subcutaneous apomorphine infusion (APO) in patients with DBS.

METHODS

We undertook a retrospective analysis of all patients treated with DBS and APO at our centre over 12 years. Subjects were allocated to four groups: (1) APO temporarily before DBS, (2) APO after DBS complications before a new DBS, (3) APO after definitive DBS removal, and (4) APO in patients with DBS and declining response. Motor state and other parameters were analysed and compared for the different treatments.

RESULTS

Data for 71 patients were evaluated. Group 1: (n = 18) patients improved their motor function significantly with both APO and DBS (off-hours before APO 5.4 ± 1.4; after APO 1.4 ± 1.2, p > 0.001; after DBS 0.7 ± 0.8, p < 0.001). Group 2: (n = 11) patients were found to have mild but significant worsening of motor state between the first DBS treatment (off-hours 0.7 ± 1.0) and APO (2.2 ± 1.5, p = 0.02), and improvement between APO and the second DBS treatment (off-hours 0.6 ± 0.8, p = 0.03). Group 3: (n = 12) patients had mild but significant worsening of motor function between DBS (off-hours 1.1 ± 1.0) and APO (2.0 ± 0.9, p = 0.03). Group 4: (n = 13) significant improvement in motor function was observed between DBS alone (off-hours 3.9 ± 2.6) and DBS combined with APO (2.2 ± 1.3, p = 0.03).

CONCLUSION

In advanced PD, DBS may be not sufficient or may fail to control motor symptoms adequately. In these cases, APO, whether alone or in combination with DBS, is a good choice to improve the disease control.

Peri-lead edema after deep brain stimulation surgery for Parkinson's disease: a prospective magnetic resonance imaging study

BACKGROUND AND PURPOSE

The aim of this study was to define the prevalence and characteristics of peri-electrode edema in a prospective cohort of patients undergoing deep brain stimulation (DBS) surgery and to correlate it with clinical findings.

METHODS

We performed brain magnetic resonance imaging (MRI) between 7 and 20 days after surgery in 19 consecutive patients undergoing DBS surgery for Parkinson's disease. The T2-weighted hyperintensity surrounding DBS leads was characterized and quantified. Any evidence of bleeding around the leads was also evaluated. Clinical and follow-up data were recorded. In a subgroup of patients, a follow-up MRI was performed 3-6 weeks after surgery. We also retrospectively reviewed the post-operative computed tomography scans of patients who underwent DBS at our center since 2013.

RESULTS

Magnetic resonance imaging showed a peri-lead edematous reaction in all (100%) patients, which was unilateral in three patients (15.8%). In six patients (31.6%), we detected minor peri-lead hemorrhage. Edema completely resolved in eight out of 11 patients with a follow-up MRI and was markedly reduced in the others. Most patients were asymptomatic but six (31.6%) manifested various degrees of confusional state without motor symptoms. We found no significant correlation between edema volume, distribution and any clinical feature, including new post-operative neurological symptoms. The retrospective computed tomography analysis showed that peri-electrode hypodensity consistent with edema is absent at early post-operative imaging but is common at scans performed >3 days after surgery.

CONCLUSIONS

Peri-electrode edema is a common, transient reaction to DBS lead placement and a convincing relation between edema and post-operative clinical status is lacking.

Experience Reduces Surgical and Hardware-Related Complications of Deep Brain Stimulation Surgery: A Single-Center Study of 181 Patients Operated in Six Years

Objective

Deep brain stimulation (DBS) surgery has increasingly been performed for the treatment of movement disorders and is associated with a wide array of complications. We aimed to present our experience and discuss strategies to minimize adverse events in light of this contemporary series and others in the literature.

Methods

A retrospective chart review was conducted to collect data on age, sex, indication, operation date, surgical technique, and perioperative and late complications.

Results

A total of 181 patients (113 males, 68 females) underwent DBS implantation surgery (359 leads) in the past six years. Indications and targets were as follows: Parkinson's disease (STN) (n=159), dystonia (GPi) (n=13), and essential tremor (Vim) (n=9). Mean age was 55.2 ± 11.7 (range 9-74) years. Mean follow-up duration was 3.4 ± 1.6 years. No mortality or permanent morbidity was observed. Major perioperative complications were confusion (6.6%), intracerebral hemorrhage (2.2%), stroke (1.1%), and seizures (1.1%). Long-term adverse events included wound (7.2%), mostly infection, and hardware-related (5.5%) complications. Among several factors, only surgical experience was found to be related with overall complication rates (early period: 31% versus late period: 10%; p=0.001).

Conclusion

The rates of both early and late complications of DBS surgery are acceptably low and decrease significantly with cumulative experience.

Spontaneous Regression of an Intraparenchymal Cyst Following Deep Brain Stimulator Electrode Implantation: Case Report and Literature Review

BACKGROUND

The development of an intraparenchymal cyst following deep brain stimulation (DBS) surgery is an uncommon complication that lacks a clearly defined management strategy. The pathophysiology is not known and may be related to perielectrode edema or cerebrospinal fluid tracking. Previous case reports have described various therapies for symptomatic cysts, including hardware removal or conservative treatment with steroids.

CASE DESCRIPTION

We present a male patient with bilateral DBS of the ventral intermediate nucleus of the thalamus for management of essential tremor, who developed a cystic cavitation at the left electrode tip and was followed without treatment. This patient developed dysarthria, gait impairment, and unilateral motor deficits 3 months after surgery. Perielectrode edema was initially identified, eventually coalescing into a cystic cavitation at the electrode tip. Cystic regression and symptomatic improvement were observed without any surgical or medical intervention, with full cyst resolution by 17 months.

CONCLUSIONS

Only 15 additional cases have been reported in the literature, although the true incidence may be underreported because of varying practices in obtaining postoperative scans. Cysts were identified in symptomatic patients on average 6.2 months after surgery. All symptomatic cysts were treated with hardware removal or steroid therapy. Observation alone may be sufficient when a DBS-associated cyst is identified. More reports are needed to characterize this rare complication.