Reducing Hardware-Related Complications of Deep Brain Stimulation

Does Temporary Externalization of Electrodes After Deep Brain Stimulation Surgery Result in a Higher Risk of Infection?

OBJECTIVES

Deep brain stimulation (DBS) is a well-established surgical therapy for movement disorders that comprises implantation of stimulation electrodes and a pacemaker. These procedures can be performed separately, leaving the possibility of externalizing the electrodes for local field potential recording or testing multiple targets for therapeutic efficacy. It is still debated whether the temporary externalization of DBS electrodes leads to an increased risk of infection. We therefore aimed to assess the risk of infection during and after lead externalization in DBS surgery.

MATERIALS AND METHODS

In this retrospective study, we analyzed a consecutive series of 624 DBS surgeries, including 266 instances with temporary externalization of DBS electrodes for a mean of 6.1 days. Patients were available for follow-up of at least one year, except in 15 instances. In 14 patients with negative test stimulation, electrodes were removed. All kinds of infections related to implantation of the neurostimulation system were accounted for.

RESULTS

Overall, infections occurred in 22 of 624 surgeries (3.5%). Without externalization of electrodes, infections were noted after 7 of 358 surgeries (2.0%), whereas with externalization, 15 of 252 infections were found (6.0%). This difference was significant (p = 0.01), but it did not reach statistical significance when comparing groups within different diagnoses. The rate of infection with externalized electrodes was highest in psychiatric disorders (9.1%), followed by Parkinson's disease (7.3%), pain (5.7%), and dystonia (5.5%). The duration of the externalization of the DBS electrodes was comparable in patients who developed an infection (6.1 ± 3.1 days) with duration in those who did not (6.0 ± 3.5 days).

CONCLUSIONS

Although infection rates were relatively low in our study, there was a slightly higher infection rate when DBS electrodes were externalized. On the basis of our results, the indication for electrode externalization should be carefully considered, and patients should be informed about the possibility of a higher infection risk when externalization of DBS electrodes is planned.

Complications of deep brain stimulation in Parkinson's disease: a single-center experience of 517 consecutive cases

BACKGROUND

The number of deep brain stimulation (DBS) procedures is rapidly rising as well as the novel indications. Reporting adverse events related to surgery and to the hardware used is essential to define the risk-to-benefit ratio and develop novel strategies to improve it.

OBJECTIVE

To analyze DBS complications (both procedure-related and hardware-related) and further assess potential predictive factors.

METHODS

Five hundred seventeen cases of DBS for Parkinson's disease were performed between 2006 and 2021 in a single center (mean follow-up: 4.68 ± 2.86 years). Spearman's Rho coefficient was calculated to search for a correlation between the occurrence of intracerebral hemorrhage (ICH) and the number of recording tracks. Multiple logistic regression analyzed the probability of developing seizures and ICH given potential risk factors. Kaplan-Meier curves were performed to analyze the cumulative proportions of hardware-related complications.

RESULTS

Mortality rate was 0.2%, while permanent morbidity 0.6%. 2.5% of cases suffered from ICH which were not influenced by the number of tracks used for recordings. 3.3% reported seizures that were significantly affected by perielectrode brain edema and age. The rate of perielectrode brain edema was significantly higher for Medtronic's leads compared to Boston Scientific's (Χ2(1)= 5.927, P= 0.015). 12.2% of implants reported Hardware-related complications, the most common of which were wound revisions (7.2%). Internal pulse generator models with smaller profiles displayed more favorable hardware-related complication survival curves compared to larger designs (X2(1)= 8.139, P= 0.004).

CONCLUSION

Overall DBS has to be considered a safe procedure, but future research is needed to decrease the rate of hardware-related complications which may be related to both the surgical technique and to the specific hardware's design. The increased incidence of perielectrode brain edema associated with certain lead models may likewise deserve future investigation.

Use of a Pericranial Flap Technique for Deep Brain Stimulation Hardware Protection and Improved Cosmesis

OBJECTIVES

Deep brain stimulation (DBS) has become an established neuromodulation therapy; however, surgical site complications such as hardware skin erosion remain an important risk and can predispose to infection, requiring explantation of the system. Nuances of surgical technique can affect wound healing, cosmetic outcome, comfort, and risk of infection. In this study, we describe our experience with a layered closure technique using a vascularized pericranial flap for improving cosmesis and protection of the implanted hardware against skin erosion and infection.

MATERIALS AND METHODS

We retrospectively reviewed 636 individuals (746 lead implantations) who underwent DBS surgery by a single academic neurosurgeon between 2001 and 2020. A layered pericranial flap closure technique for the burr-hole and connector sites was instituted in 2015. We assessed the effects of a multimodal infection prevention approach that included the pericranial flap on hardware complication rates compared with the premultimodality cohort, and we report the nuances of the technique.

RESULTS

In our institutional experience, we found that implementation of a pericranial flap closure technique can enhance the subjective cosmetic result at the burr-hole cover site and increase patient comfort and satisfaction. In addition, we found a decrease in hardware infection rates in the current cohort with a multimodal infection prevention regimen that includes the pericranial-flap technique (n = 256, 2015-2020 period) to 1.2% (p = 0.006), from 6.9% in the earlier cohort (n = 490, 2001-2015 period).

CONCLUSIONS

The report highlights the potential of a pericranial-flap closure technique as a surgical adjunct to improve DBS surgical site healing and cosmesis and may, as part of a multimodal strategy, contribute to decreased risk of skin breakdown and hardware infection.

Surgical Site Infections Associated With Implanted Pulse Generators for Deep Brain Stimulation: Meta-Analysis and Systematic Review

OBJECTIVES

The aim of this study was to identify and systematically analyze relevant literature on surgical site infections (SSIs) associated with implantable pulse generator (IPG) procedures for deep brain stimulation (DBS).

MATERIALS AND METHODS

In compliance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we conducted a systematic review and meta-analyses of 58 studies that reported SSI rates of 11,289 patients and 15,956 IPG procedures. A meta-analysis of proportions was performed to estimate the pooled proportion of SSIs across DBS procedures in general and to estimate the proportion of SSIs that occur at the IPG pocket. Moreover, a meta-analysis of odds ratio (OR) was conducted on those studies that reported their results of applying topical vancomycin powder during closure of the IPG wound. Results are presented as rates and OR with 95% CIs.

RESULTS

The pooled proportion of SSIs was 4.9% (95% CI, 4.1%-6.1%) among all DBS procedures. The dominant SSI localization was the IPG pocket in 61.2% (95% CI, 53.4%-68.5%). A trend toward a beneficial effect of vancomycin powder over standard wound closure was found with an OR of 0.46 (95% CI, 0.21-1.02). Most studies (79.1%) that reported their treatment strategy in case of SSI had a strict protocol of removal of the IPG, followed by antimicrobial treatment and reimplantation of the IPG once the SSI had been eradicated.

CONCLUSIONS

The IPG pocket was identified as the main site of SSI after DBS procedures. Most studies recommend complete IPG removal, antimicrobial treatment, and reimplantation of an IPG once the SSI has been eradicated. Future studies are needed to clarify the role of alternative approaches (eg, topical vancomycin powder) in the prevention of SSI associated with IPG.

Skin-related complications following deep brain stimulation surgery: A single-center retrospective analysis of 525 patients who underwent DBS surgery

BACKGROUND

Although Deep Brain Stimulation (DBS) is a safe and proven treatment modality for patients suffering from debilitating movement and neuropsychiatric disorders, it is not free from complications. Management of skin erosion and infection following DBS surgery constitutes a challenge in everyday clinical practice.

OBJECTIVES

Skin-related complications were evaluated in patients who underwent DBS surgery due to Parkinson's disease (PD), dystonia, essential tremor (ET), and other indications including Tourette syndrome (TS), Obsessive-Compulsive Disorder (OCD), and epilepsy.

METHODS

A retrospective analysis of clinical data was performed on patients who underwent DBS surgery between November 2008 and September 2021 at the Department of Neurosurgery, Institute of Psychiatry and Neurology, Warsaw.

RESULTS

525 patients who underwent 927 DBS leads implantations were included in the analysis. There were 398 patients with PD, 80 with dystonia, 26 with ET, 7 with drug-resistant epilepsy, 5 with Multiple Sclerosis, 4 with Holme's or cerebellar tremor, 3 with TS, and 2 with OCD. 42 patients (8,0%) had 78 skin infection episodes. The overall level of skin erosion was 3,8% (20/525 patients). The risk of developing infection episode was connected with younger age at diagnosis (p = 0.017) and at surgery (p = 0.023), whereas the development of skin erosion was connected with the dystonia diagnosis (p = 0.012). Patients with dystonia showed the highest rate of infections and erosions (11/70 and 7/70 patients retrospectively).

DISCUSSION

Postoperative skin complications are a serious side effect of DBS surgery.

CONCLUSION

Our study suggests that dystonic patients are at higher risk of developing skin-related complications after DBS surgery.

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.

Estimation of ANT-DBS Electrodes on Target Positioning Based on a New PerceptTM PC LFP Signal Analysis

Deep brain stimulation of the Anterior Nucleus of the Thalamus (ANT-DBS) is an effective therapy in epilepsy. Poorer surgical outcomes are related to deviations of the lead from the ANT-target. The target identification relies on the visualization of anatomical structures by medical imaging, which presents some disadvantages. This study aims to research whether ANT-LFPs recorded with the Percept^TM PC neurostimulator can be an asset in the identification of the DBS-target. For this purpose, 17 features were extracted from LFPs recorded from a single patient, who stayed at an Epilepsy Monitoring Unit for a 5-day period. Features were then integrated into two machine learning (ML)-based methodologies, according to different LFP bipolar montages: Pass1 (nonadjacent channels) and Pass2 (adjacent channels). We obtained an accuracy of 76.6% for the Pass1-classifier and 83.33% for the Pass2-classifier in distinguishing locations completely inserted in the target and completely outside. Then, both classifiers were used to predict the target percentage of all combinations, and we found that contacts 3 (left hemisphere) and 2 and 3 (right hemisphere) presented higher signatures of the ANT-target, which agreed with the medical images. This result opens a new window of opportunity for the use of LFPs in the guidance of DBS target identification.

Involvement of the Anterior Nucleus of the Thalamus during Focal Automatisms in Epileptic Seizures: A First Evidence Study

The Anterior Nucleus of Thalamus (ANT) Deep Brain Stimulation (DBS) has long been touted as the most effective DBS-target for interrupting seizures in focal refractory epilepsy patients. The ANT is primarily involved in cognitive tasks but has extensive reciprocal connections with motor-related regions, suggesting that it is also involved in motor-cognitive tasks. In this work, we aimed to assess the involvement of the ANT during voluntary upper limbs movements. For this purpose, we analyzed Local Field Potentials (LFPs) signals recorded during a movement protocol from one of the first epilepsy patients implanted with a Percept™ PC system, who performed a 5-day period of simultaneous video electroencephalography (vEEG) and Percept PC-LFPs recordings. We estimated time-frequency maps and performed event-related desynchronization (ERD) or synchronization (ERS) analysis and we found that synchronizations found in left hemisphere 7-17 Hz map corresponded to maximum hand rotations. Positive peaks on the ERD/ERS curve occurred at a similar frequency of the hand movements ([Formula: see text] against [Formula: see text]). These results suggested that the ANT may be involved in the execution of automatisms. Moreover, we found that ERD/ERS appeared approximately 2 seconds before the movement onset, as it was found on the EEG of healthy subjects performing the same protocol.

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.

Is It Possible to Save the Deep Brain Stimulation Hardware when Presenting with Wound Dehiscence or Hardware Infection?

INTRODUCTION

Deep brain stimulation (DBS) hardware complications have been traditionally managed by removal of the entire system. Explantation of the system results in prolonged interruption to the patient's care and potential challenges when considering reimplantation of the cranial leads. The purpose of this study was to understand whether complete explantation can be avoided for patients initially presenting with wound dehiscence and/or infection of hardware.

METHODS

We performed a retrospective study that included 30 cases of wound dehiscence or infection involving the DBS system. Patients underwent reoperation without explantation of the DBS system, with partial explanation, or with complete explantation as initial management of the complication.

RESULTS

A total of 17/30 cases were managed with hardware-sparing wound revisions. The majority presented with wound dehiscence (94%), with the scalp (n = 9) as the most common location. This was successful in 76.5% of patients (n = 13). Over 11/30 patients were managed with partial explantation. The complication was located at the generator (91%) or at the scalp (9%). Partial explantation was successful in 64% of patients (n = 7). In cases that underwent a lead-sparing approach, 33% of patients ultimately required removal of the intracranial lead, and 2/30 cases of hardware infection were managed initially with total explantation.

DISCUSSION/CONCLUSION

Wound dehiscence can be successfully managed without complete removal of the DBS system in most cases. In cases of infection, removing the involved component(s) and sparing the intracranial leads may be considered. Wound revision without removal of the entire DBS system is safe and can improve quality of life by preventing or shortening the withdrawal of DBS treatment.

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.

Risk of Infection after Deep Brain Stimulation Surgery with Externalization and Local-Field Potential Recordings: Twelve-Year Experience from a Single Institution

INTRODUCTION

Deep brain stimulation (DBS) has been an established surgical procedure in the field of functional neurosurgery for many years. The experimental electrophysiological method of local field potential (LFP) recordings in postsurgically externalized patients has made substantial contributions to the better understanding of pathophysiologies underlying movement disorders. As interest in LFP recordings for the development of improved stimulation strategies increases, this study's aim was to provide evidence concerning safety of this research method, in a major DBS center.

METHODS

We retrospectively analyzed incidence and infection characteristics in adult patients who underwent two-staged DBS surgery with temporary externalization of leads in our center between January 2008 and November 2019. We focused on whether patients had participated in LFP recordings, and evaluated incidence of infections at 3 months and 1 year after the surgery based on medical records. Infection rates were compared to major DBS studies and reports focusing on the risk of infection due to externalization of DBS leads. Results were visualized using descriptive statistics.

RESULTS

Between January 2008 and November 2019, DBS surgery was performed in 528 patients (389/139 patients in the LFP/non-LFP group), mainly for movement disorders such as Parkinson's disease (308), dystonia (93), and essential tremor (86). Of the patients, 72.9% participated in LFP recordings. The incidence of infections in the acute postsurgical phase (3 months) was 2.46% and did not differ significantly between the LFP group (1.8%) and the non-LFP group (4.32%). The overall incidence after 1 year amounted to 3.6% (19 patients) with no difference between LFP/non-LFP groups. Incidence rates reported in the literature show a large variety (2.6-10%), and the incidence reported here is within the lower range of reported incidences.

DISCUSSION/CONCLUSION

This study demonstrates that DBS is a surgical procedure with a low risk of infection in a large patient cohort. Importantly, it shows that LFP recordings do not have a significant effect on the incidence of infections in patients with externalization. With a representative cohort of more than 380 patients participating in LFP-recordings, this underlines LFP as a safe method in research and supports further use of this method, for example, for the development of adaptive stimulation protocols.

Surgical and Hardware Complications of Deep Brain Stimulation-A Single Surgeon Experience of 519 Cases Over 20 Years

OBJECTIVE

Deep brain stimulation (DBS) surgery has its own set of risks and complications. This study from a single center and a single surgeon analyzes various risk factors for complications and tries to establish if there is a learning curve effect in minimizing the complications.

MATERIALS AND METHODS

A retrospective analysis of 519 patients (1024 leads) who underwent DBS surgery and 232 patients who underwent implantable pulse generator replacement (IPG), by a single surgeon, between the years 1999 and 2019 was performed. Perioperative and hardware related complications were evaluated.

RESULTS

The follow-up period ranged from six months to 20 years. Surgery-related complications occurred in 46 (8.9%) cases which included confusion in 31 (5.98%), intracerebral hemorrhage in 7 (1.3%), vasovagal attack in 3 (0.58%), respiratory distress in 2 (0.38%), postoperative aggressiveness in 1 (0.19%), and blepharospasm in 2 (0.38%) patients. Complications related to the DBS hardware were found in 35 cases, including erosion and infection in 22 (2.95%), inaccurate lead placement or migration in 6 (0.6%) lead fracture/extension wire failure in 2 (0.26%), IPG malfunction in 2 (0.26%), and hardware discomfort in 3 (0.4%) cases. In three patients, one lead was repositioned. In cases of infection, 87% of patients had either partial or complete removal of hardware. There was no mortality. The complications were analyzed for every 100 DBS procedures. There was a significant drop in the percentage of complications in from 23% in the first 100 cases to 7% in the last 100 cases (p < 0.0001).

CONCLUSION

Confusion remains the most frequent operative and perioperative complication. Erosion and infection of the surgical site represents the most frequent hardware complication. DBS surgery is safe and the complication rates are acceptably low. The complication rate also decreases with cumulative years of experience, demonstrating a learning curve effect.

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.

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.

A qualitative study of key stakeholders' perceived risks and benefits of psychiatric electroceutical interventions

Amid a renewed interest in alternatives to psychotherapy and medication to treat depression, there is limited data as to how different stakeholders perceive of the risks and benefits of psychiatric electroceutical interventions (PEIs), including electroconvulsive therapy (ECT) and deep brain stimulation (DBS). To address this gap, we conducted 48 semi-structured interviews, including 16 psychiatrists, 16 persons diagnosed with depression, and 16 members of the general public. To provide a basis of comparison, we asked participants to also compare each modality to front-line therapies for depression and to neurosurgical procedures used for non-psychiatric conditions. Across all stakeholder groups, perceived memory loss was the most frequently mentioned potential risk with ECT. The most discussed benefits across all stakeholder groups were efficacy and quick response. Psychiatrists most often referenced effectiveness when discussing ECT, while patients and the public did so when discussing DBS. Taken as a whole, these data highlight stakeholders' contrasting perspectives on the risks and benefits of electroceuticals.

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.

Reconstruction of chronic scalp erosion after deep brain stimulation surgery

OBJECTIVE

To investigate the reconstructive effectiveness for chronic scalp erosion after deep brain stimulation (DBS).

BACKGROUND

Deep brain stimulation (DBS) is an effective treatment for Parkinson's disease. However, this surgery is not exempt from hard-ware related complications, especially scalp erosions on scalp. Scalp erosions usually accompanied with chronic infection and wound contamination. If not arrested, infections may spread through the entire equipment which would endanger the patient's life. Along with review of previous literatures, we summarized our experience in the management of scalp erosion and implemented a systemic treatment plan for reconstruction.

METHODS

We retrospectively analyzed the clinical data of patients with chronic scalp erosion after DBS in the past 40 months. The treatment plan was composed of three sequential major steps, including wound care and conservative methods, debridement and local flap, and revaluation of the wound. In each of the cases, wound debridement and local scalp flap repair were conducted, and assisted by negative pressure wound therapy (NPWT) device and double cannula irrigation.

RESULTS

The local scalp flap survived in all 6 patients. The chronic scalp erosions all healed without refractory. The DBS devices still functioned properly after the treatments in all patients. The average follow-up period was 13.33 months (range: 4 to 23 months), and no infection recurrence or re-erosion of the scalp flap was reported.

CONCLUSION

A combination of wound debridement, local scalp flap repair, the use of NPWT device and double cannula irrigation provides effective treatment method for chronic erosion post DBS surgery.

Parkinson's disease and skin

Parkinson's disease is associated with a variety of dermatologic disorders and the study of skin may provide insights into pathophysiological mechanisms underlying this common neurodegenerative disorder. Skin disorders in patients with Parkinson's disease can be divided into two major groups: 1) non-iatrogenic disorders, including melanoma, seborrheic dermatitis, sweating disorders, bullous pemphigoid, and rosacea, and 2) iatrogenic disorders related either to systemic side effects of antiparkinsonian medications or to the delivery system of antiparkinsonian therapy, including primarily carbidopa/levodopa, rotigotine and other dopamine agonists, amantadine, catechol-O-methyl transferase inhibitors, subcutaneous apomorphine, levodopa/carbidopa intestinal gel, and deep brain stimulation. Recent advances in our understanding of the role of α-synuclein in peripheral tissues, including the skin, and research based on induced pluripotent stem cells derived from skin fibroblasts have made skin an important target for the study of Parkinson's disease pathogenesis, drug discovery, novel stem cell therapies, and diagnostics.

A Deep Brain Stimulation Trial Period for Treating Chronic Pain

Early studies of deep brain stimulation (DBS) for various neurological disorders involved a temporary trial period where implanted electrodes were externalized, in which the electrical contacts exiting the patient's brain are connected to external stimulation equipment, so that stimulation efficacy could be determined before permanent implant. As the optimal brain target sites for various diseases (i.e., Parkinson's disease, essential tremor) became better established, such trial periods have fallen out of favor. However, deep brain stimulation trial periods are experiencing a modern resurgence for at least two reasons: (1) studies of newer indications such as depression or chronic pain aim to identify new targets and (2) a growing interest in adaptive DBS tools necessitates neurophysiological recordings, which are often done in the peri-surgical period. In this review, we consider the possible approaches, benefits, and risks of such inpatient trial periods with a specific focus on developing new DBS therapies for chronic pain.

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.

Negative Pressure Wound Therapy With Chymotrypsin Irrigation: A Maximal Implant Retention Procedure Treating the Exposure/Infection of Titanium Mesh in Cranioplasty

This preliminary study aims to investigate the effects of a maximal implant retention procedure. The authors retrospectively reviewed the use of negative pressure wound therapy with chymotrypsin irrigation treating implant infection/exposure in titanium mesh cranioplasty by comparing patients with titanium mesh totally retained, partially removed, or totally removed according to the evaluation during the surgery. Negative pressure wound therapy with chymotrypsin irrigation was applied 5 days after the surgery. The negative pressure was set at -125 to -150 mmHg. A total of 21 patients were included, 4 patients treated with titanium mesh totally removed; 3 patients treated with titanium mesh partially removed; and 14 patients treated with U-shape debridement with titanium mesh preserved completely. However, 1 patient in the U-shape group required a second debridement to remove all implant. Negative pressure wound therapy with chymotrypsin irrigation is a novel procedure and could be used to treat implant-related infection without the exchange of implant.

Feasibility of changing for a rechargeable constant current neurostimulator in Parkinson's disease

BACKGROUND

Little is known about outcome and settings adaptations after replacement of constant-voltage non-rechargeable implantable pulse generator (CV-nrIPG) by constant-current rechargeable IPG (CC-rIPG).

OBJECTIVE

To determine the feasibility and safety of replacing a CV-nrIPG by a CC-rIPG in Parkinson's disease (PD) and the subsequent outcome.

METHODS

A prospective cohort of thirty PD patients, whose CV-nrIPG was replaced by a CC-rIPG in University Hospital of Lyon between January 2017 and December 2018 (rIPG group) and 39 PD patients, who underwent the replacement of a CV-nrIPG by the same device in 2016 (nrIPG group), were enrolled in this study. Three surgeons performed the operations. Duration of hospitalization for the replacement as well as the number of in or outpatient visits during the first 3 months after the surgery were recorded. In the rIPG group, we compared preoperative DBS settings and the theoretical amplitude estimated using Ohm's law to the amplitude used at the end of follow-up. We assessed patients' and clinicians' opinion on the patient global functioning after the replacement using Clinical Global Impression score.

RESULTS

Duration of hospitalization (P=0.47) and need for additional hospitalizations (P=0.73) or consultations (P=0.71) to adapt DBS parameters did not differ between the two groups. Neurological condition (CGI score) was considered as unchanged by both patients and neurologists. Final amplitude of stimulation using CC-rIPG was not predicted by Ohm's law in most cases.

CONCLUSIONS

Replacing CV-nrIPG by CC-rIPG is safe and well tolerated but require neurological expertise to set the new parameters of stimulation.

Antibiotic Impregnated Catheter Coating Technique for Deep Brain Stimulation Hardware Infection: An Effective Method to Avoid Intracranial Lead Removal

BACKGROUND

Few studies have proposed alternative salvage methods of deep brain stimulation (DBS) intracranial lead once the infection has already occurred.

OBJECTIVE

To assess the effectiveness of antibiotic impregnated catheter coverage of DBS leads in case of hardware infection.

METHODS

Patients with a hardware infection and consequent partial removal of extension and internal pulse generator (IPG) were reviewed. To diagnose an infection, criteria provided by the Guideline for Prevention of Surgical Site Infection were used. We compared the intracranial lead salvage rate between the group that underwent antibiotic catheter lead protection (group A) and the group that did not (group B).

RESULTS

A total of 231 DBS surgeries and 339 IPG replacements were performed from January 2012 to January 2017. Twenty-three hardware-related infections (4%) were identified. Nineteen patients (82.6%) underwent partial hardware removal with an attempt to spare intracranial lead. Of these, 8 patients (42.1%) had antibiotic catheter lead coverage (group A) while 11 patients (57.9%) did not receive any antibiotic protection (group B). At 6-mo follow-up, 6 patients had the extension and IPG successfully re-implanted in group A, whereas only 1 patient was successfully re-implanted in group B (75 vs 9.1%; P < .001).

CONCLUSION

The antibiotic impregnated catheter coating technique seems to be effective in avoiding intracranial lead removal in case of IPG or DBS extension-lead junction infection. This method does not require any surgical learning curve, it is safe and relatively inexpensive. Randomized, prospective, larger studies are needed to validate our results.

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.

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.

Towards unambiguous reporting of complications related to deep brain stimulation surgery: A retrospective single-center analysis and systematic review of the literature

Background and objective

To determine rates of adverse events (AEs) related to deep brain stimulation (DBS) surgery or implanted devices from a large series from a single institution. Sound comparisons with the literature require the definition of unambiguous categories, since there is no consensus on the reporting of such AEs.

Patients and methods

123 consecutive patients (median age 63 yrs; female 45.5%) treated with DBS in the subthalamic nucleus (78 patients), ventrolateral thalamus (24), internal pallidum (20), and centre médian-parafascicular nucleus (1) were analyzed retrospectively. Both mean and median follow-up time was 4.7 years (578 patient-years). AEs were assessed according to three unambiguous categories: (i) hemorrhages including other intracranial complications because these might lead to neurological deficits or death, (ii) infections and similar AEs necessitating the explantation of hardware components as this results in the interruption of DBS therapy, and (iii) lead revisions for various reasons since this involves an additional intracranial procedure. For a systematic review of the literature AE rates were calculated based on primary data presented in 103 publications. Heterogeneity between studies was assessed with the I² statistic and analyzed further by a random effects meta-regression. Publication bias was analyzed with funnel plots.

Results

Surgery- or hardware-related AEs (23) affected 18 of 123 patients (14.6%) and resolved without permanent sequelae in all instances. In 2 patients (1.6%), small hemorrhages in the striatum were associated with transient neurological deficits. In 4 patients (3.3%; 0.7% per patient-year) impulse generators were removed due to infection. In 2 patients electrodes were revised (1.6%; 0.3% per patient-year). There was no lead migration or surgical revision because of lead misplacement. Age was not statistically significant different (p>0.05) between patients affected by AEs or not. AE rates did not decline over time and similar incidences were found among all patients (423) implanted with DBS systems at our institution until December 2016. A systematic literature review revealed that exact AE rates could not be determined from many studies, which could not be attributed to study designs. Average rates for intracranial complications were 3.8% among studies (per-study analysis) and 3.4% for pooled analysis of patients from different studies (per-patient analysis). Annual hardware removal rates were 3.6 and 2.4% for per-study and per-patient analysis, respectively, and lead revision rates were 4.1 and 2.6%, respectively. There was significant heterogeneity between studies (I² ranged between 77% and 91% for the three categories; p< 0.0001). For hardware removal heterogeneity (I² = 87.4%) was reduced by taking study size (p< 0.0001) and publication year (p< 0.01) into account, although a significant degree of heterogeneity remained (I² = 80.0%; p< 0.0001). Based on comparisons with health care-related databases there appears to be publication bias with lower rates for hardware-related AEs in published patient cohorts.

Conclusions

The proposed categories are suited for an unequivocal assessment of AEs even in a retrospective manner and useful for benchmarking. AE rates in the present cohorts from our institution compare favorable with the literature.

Cerebrospinal Fluid Egress from the Quadripolar Deep Brain Stimulation Electrode for Anterior Nucleus of the Thalamus for Refractory Epilepsy

Deep brain stimulation (DBS) of the anterior nucleus of the thalamus (ANT) is an effective treatment for refractory epilepsy. Due to the unique location of ANT in the thalamus facing the lateral and third ventricles, transventricular DBS lead placement is an essential part of ANT DBS. However, there is no report regarding hardware problems including impedance variability in transventricular ANT DBS due to limited experience. A 45-year-old male patient with previously effective, bilateral ANT DBS presented with increasing seizure frequency and a shortened battery longevity within 2 years. Magnetic resonance imaging showed that the left-sided DBS lead was in the third ventricle leaning on the medial wall of ANT. Electrode revision was performed. Upon disconnecting the proximal lead from the extension connection, cerebrospinal fluid egress through fine gaps between the metallic electrode contacts, and electrode spacing was observed. This case raises a concern about the transventricular approach for ANT lead placement because the currently available DBS electrode lead is not waterproofed. A careful, longitudinal follow-up of DBS impedance for ANT DBS is warranted.

Technical Note: Preemptive Surgical Revision of Impending Deep Brain Stimulation Hardware Erosion

BACKGROUND

While deep brain stimulation (DBS) is a relatively safe procedure, skin erosion is a commonly reported hardware complication that can threaten the DBS system. Patients with Parkinson disease are especially at risk for this complication due to their autonomic dysregulation and impaired nutrition. Early detection of impending skin erosion allows for intervention that may prevent hardware destruction. Here we report a novel technique to address this complication preemptively. We describe the use of an acellular dermal matrix to prevent skin erosion in 20 patients with Parkinson disease who were treated with DBS and showed signs of impending skin erosion.

METHODS

Twenty patients with signs of impending hardware erosion were identified. An acellular dermal matrix was surgically placed under the at-risk skin overlying the DBS lead.

RESULTS

None of the 20 patients treated with this technique went on to require further revision surgery or removal of hardware.

CONCLUSIONS

Surgical placement of acellular dermal matrix in patients identified as having impending hardware erosions is a safe and cost-effective way to prevent hardware complications.

Postoperative lead migration in deep brain stimulation surgery: Incidence, risk factors, and clinical impact

Introduction

Deep brain stimulation (DBS) is an effective treatment for multiple movement disorders and shows substantial promise for the treatment of some neuropsychiatric and other disorders of brain neurocircuitry. Optimal neuroanatomical lead position is a critical determinant of clinical outcomes in DBS surgery. Lead migration, defined as an unintended post-operative displacement of the DBS lead, has been previously reported. Despite several reports, however, there have been no systematic investigations of this issue. This study aimed to: 1) quantify the incidence of lead migration in a large series of DBS patients, 2) identify potential risk factors contributing to DBS lead migration, and 3) investigate the practical importance of this complication by correlating its occurrence with clinical outcomes.

Methods

A database of all DBS procedures performed at UF was queried for patients who had undergone multiple post-operative DBS lead localization imaging studies separated by at least two months. Bilateral DBS implantation has commonly been performed as a staged procedure at UF, with an interval of six or more months between sides. To localize the position of each DBS lead, a head CT is acquired ~4 weeks after lead implantation and fused to the pre-operative targeting MRI. The fused targeting images (MR + stereotactic CT) acquired in preparation for the delayed second side lead implantation provide an opportunity to repeat the localization of the first implanted lead. This paradigm offers an ideal patient population for the study of delayed DBS lead migration because it provides a large cohort of patients with localization of the same implanted DBS lead at two time points. The position of the tip of each implanted DBS lead was measured on both the initial post-operative lead localization CT and the delayed CT. Lead tip displacement, intracranial lead length, and ventricular indices were collected and analyzed. Clinical outcomes were characterized with validated rating scales for all cases, and a comparison was made between outcomes of cases with lead migration versus those where migration of the lead did not occur.

Results

Data from 138 leads in 132 patients with initial and delayed lead localization CT scans were analyzed. The mean distance between initial and delayed DBS lead tip position was 2.2 mm and the mean change in intracranial lead length was 0.45 mm. Significant delayed migration (>3 mm) was observed in 17 leads in 16 patients (12.3% of leads, 12.1% of patients). Factors associated with lead migration were: technical error, repetitive dystonic head movement, and twiddler’s syndrome. Outcomes were worse in dystonia patients with lead migration (p = 0.035). In the PD group, worse clinical outcomes trended in cases with lead migration.

Conclusions

Over 10% of DBS leads in this large single center cohort were displaced by greater than 3 mm on delayed measurement, adversely affecting outcomes. Multiple risk factors emerged, including technical error during implantation of the DBS pulse generator and failure of lead fixation at the burr hole site. We hypothesize that a change in surgical technique and a more effective lead fixation device might mitigate this problem.

Chronic multisite brain recordings from a totally implantable bidirectional neural interface: experience in 5 patients with Parkinson's disease

OBJECTIVE Dysfunction of distributed neural networks underlies many brain disorders. The development of neuromodulation therapies depends on a better understanding of these networks. Invasive human brain recordings have a favorable temporal and spatial resolution for the analysis of network phenomena but have generally been limited to acute intraoperative recording or short-term recording through temporarily externalized leads. Here, the authors describe their initial experience with an investigational, first-generation, totally implantable, bidirectional neural interface that allows both continuous therapeutic stimulation and recording of field potentials at multiple sites in a neural network. METHODS Under a physician-sponsored US Food and Drug Administration investigational device exemption, 5 patients with Parkinson's disease were implanted with the Activa PC+S system (Medtronic Inc.). The device was attached to a quadripolar lead placed in the subdural space over motor cortex, for electrocorticography potential recordings, and to a quadripolar lead in the subthalamic nucleus (STN), for both therapeutic stimulation and recording of local field potentials. Recordings from the brain of each patient were performed at multiple time points over a 1-year period. RESULTS There were no serious surgical complications or interruptions in deep brain stimulation therapy. Signals in both the cortex and the STN were relatively stable over time, despite a gradual increase in electrode impedance. Canonical movement-related changes in specific frequency bands in the motor cortex were identified in most but not all recordings. CONCLUSIONS The acquisition of chronic multisite field potentials in humans is feasible. The device performance characteristics described here may inform the design of the next generation of totally implantable neural interfaces. This research tool provides a platform for translating discoveries in brain network dynamics to improved neurostimulation paradigms. Clinical trial registration no.: NCT01934296 (clinicaltrials.gov).

Complication rates, lengths of stay, and readmission rates in "awake" and "asleep" deep brain simulation

OBJECTIVE As the number of deep brain stimulation (DBS) procedures performed under general anesthesia ("asleep" DBS) increases, it is more important to assess the rates of adverse events, inpatient lengths of stay (LOS), and 30-day readmission rates in patients undergoing these procedures compared with those in patients undergoing traditional "awake" DBS without general anesthesia. METHODS All patients in an institutional database who had undergone awake or asleep DBS procedures performed by a single surgeon between August 2011 and August 2014 were reviewed. Adverse events, inpatient LOS, and 30-day readmissions were analyzed. RESULTS A total of 490 electrodes were placed in 284 patients, of whom 126 (44.4%) underwent awake surgery and 158 (55.6%) underwent asleep surgery. The most frequent overall complication for the cohort was postoperative mental status change (13 patients [4.6%]), followed by hemorrhage (4 patients [1.4%]), seizure (4 patients [1.4%]), and hardware-related infection (3 patients [1.1%]). Mean LOS for all 284 patients was 1.19 ± 1.29 days (awake: 1.06 ± 0.46 days; asleep: 1.30 ± 1.67 days; p = 0.08). Overall, the 30-day readmission rate was 1.4% (1 awake patient, 3 asleep patients). There were no significant differences in complications, LOS, and 30-day readmissions between awake and asleep groups. CONCLUSIONS Both awake and asleep DBS can be performed safely with low complication rates. The authors found no significant differences between the 2 procedure groups in adverse events, inpatient LOS, and 30-day readmission rates.

An Analysis of Scalp Thickness and Other Novel Risk Factors for Deep Brain Stimulator Infections

Introduction: Deep brain stimulator (DBS) infections are a persistent problem for patients undergoing this procedure. They may require further surgery, treatment with antibiotics, or even removal of the device. To date, no consensus exists on the best practices to avoid DBS infections or what factors predispose patients to an eventual infection. The goal of this study was to examine several patient factors for association with DBS infection.

Methods: A single-center, single-surgeon quality improvement database was queried. All patients who experienced an infection were identified. The primary variable analyzed was scalp thickness. Other pre-specified, secondary variables included routine intraoperative cultures, operative time, diagnosis, and age.

Results: None of the independent variables examined were significantly associated with DBS infections. Only two of the 46 infections qualified as surgical site infections as defined by the Centers for Disease Control.

Conclusion: DBS infections are independent of all of the predictor variables analyzed. Surgical site infections, according to traditional definitions, are not the optimal definition for evaluating DBS infections/erosions. New studies must examine new variables that are not routinely gathered in this population. Also, because of the rare event rates and difficulty in randomizing patients to exposures, a large, multicenter registry may be the optimal study design to solve this clinical problem.

Adverse events associated with deep brain stimulation for movement disorders: analysis of 510 consecutive cases

BACKGROUND

Although numerous studies have focused on the efficacy of deep brain stimulation (DBS) for movement disorders, less is known about surgical adverse events, especially over longer time intervals.

OBJECTIVE

Here, we analyze adverse events in 510 consecutive cases from a tertiary movement disorders center at up to 10 years postoperatively.

METHODS

We conducted a retrospective review of adverse events from craniotomies between January 2003 and March 2013. The adverse events were categorized into 2 broad categories--immediate perioperative and time-dependent postoperative events.

RESULTS

Across all targets, perioperative mental status change occurred in 18 (3.5%) cases, and symptomatic intracranial hemorrhage occurred in 4 (0.78%) cases. The most common hardware-related event was skin erosion in 13 (2.5%) cases. The most frequent stimulation-related event was speech disturbance in 16 (3.1%) cases. There were no significant differences among surgical targets with respect to the incidence of these events. Time-dependent postoperative events leading to the revision of a given DBS electrode for any reason occurred in 4.7% ± 1.0%, 9.3% ± 1.4%, and 12.4% ± 1.5% of electrodes at 1, 4, and 7 years postoperatively, respectively. Staged bilateral DBS was associated with approximately twice the risk of repeat surgery for electrode replacement vs unilateral surgery (P = .020).

CONCLUSION

These data provide low incidences for adverse events in a large series of DBS surgeries for movement disorders at up to 10 years follow-up. Accurate estimates of adverse events will better inform patients and caregivers about the potential risks and benefits of surgery and provide normative data for process improvement.

Chronological Changes of C-Reactive Protein Levels Following Uncomplicated, Two-Staged, Bilateral Deep Brain Stimulation

Objective

The occurrence of acute cerebral infection following deep brain stimulation (DBS) is currently being reported with elevation of C-reactive protein (CRP) level. The aim of the present study was to establish normal range of the magnitude and time-course of CRP increases following routine DBS procedures in the absence of clinical and laboratory signs of infection.

Methods

A retrospective evaluation of serial changes of plasma CRP levels in 46 patients undergoing bilateral, two-staged DBS was performed. Because DBS was performed as a two-staged procedure involving; implantation of lead and internal pulse generator (IPG), CRP was measured preoperatively and postoperatively every 2 days until normalization of CRP (post-lead implantation day 2 and 4, post-IPG implantation day 2, 4, and 6).

Results

Compared with preoperative CRP levels (0.12±0.17 mg/dL, n=46), mean CRP levels were significantly elevated after lead insertion day 2 and 4 (1.68±1.83 mg/dL, n=46 and 0.76±0.38 mg/dL, n=16, respectively, p<0.001). The mean CRP levels at post-lead implantation day 2 were further elevated at post-IPG implantation day 2 (3.41±2.56 mg/dL, n=46, respectively, p<0.01). This elevation in post-IPG day 2 rapidly declined in day 4 (1.24±1.29 mg/dL, n=46, p<0.05) and normalized to preoperative value at day 6 (0.42±0.33 mg/dL, n=46, p>0.05). Mean CRP levels after IPG implantation were significantly higher in patients whose IPGs were implanted at post-lead day 3 than those at post-lead day 5-6 (3.99±2.80 mg/dL, n=30, and 2.31±1.56 mg/dL, n=16, respectively, p<0.05). However, there was no difference in post-IPG day 2 and 4 between them (p>0.05).

Conclusion

The mean postoperative CRP levels were highest on post-IPG insertion day 2 and decreased rapidly, returning to the normal range on post-IPG implantation day 6. The duration of post-lead implantation period influenced the magnitude of CRP elevation at post-IPG insertion day 2. Information about the normal response of CRP following DBS could help to avoid unnecessary diagnostic and therapeutic efforts.

Sudden loss of the deep brain stimulation effect with high impedance without macroscopic fracture: a case report and review of the published literature

The number of deep brain stimulation (DBS) hardware complications has increased during the past decade. In cases of abnormally high lead impedance with no evidence of a macroscopic fracture, optimal treatment options have not yet been established. Here, we present the case of a 49-year-old woman with a 12-year history of Parkinson's disease who received bilateral subthalamic nucleus DBS in March 2006. The patient showed good control of parkinsonism until December 24, 2010, when she awoke with abrupt worsening of parkinsonian symptoms. At telemetric testing, lead impedances were found at >2,000 Ω in all four leads on the left side. Fracture of a lead or an extension wire was suspected. However, radiological screening and palpation revealed no macroscopic fracture. In June 2011, the implantable pulse generator (IPG) was changed under local anesthesia without any complications. Postoperatively, her parkinsonism immediately improved to the previous level, and the lead impedance readings by telemetry were also normalized. The disconnection of the neurostimulator connector block and the hybrid circuit board of the IPG was confirmed by destructive analysis. The present report illustrates that a staged approach that starts with simple IPG replacement can be an option for some cases of acute DBS effect loss with high impedance, when radiological findings are normal, thereby sparing the intact electrodes and extension wires.