Search

Objectives One of the main challenges posed by the surgical deep brain stimulation (DBS) procedure is the successful targeting of the structures of interest and avoidance of side effects, especially in asleep surgery. Here, intraoperative motor evoked potentials (MEPs) might serve as tool to identify the pyramidal tract. We hypothesized that intraoperative MEPs are useful to define the distance to the pyramidal tract and reduce the occurrence of postoperative capsular side effects. Materials and methods Motor potentials were evoked through both microelectrode and DBS-electrode stimulation during stereotactic DBS surgery on 25 subthalamic nuclei and 3 ventral intermediate thalamic nuclei. Internal capsule proximity was calculated for contacts on microelectrode trajectories, as well as for DBS-electrodes, and correlated with the corresponding MEP thresholds. Moreover, the predictivity of intraoperative MEP thresholds on the probability of postoperative capsular side effects was calculated. Results Intraoperative MEPs thresholds correlated significantly with internal capsule proximity, regardless of the stimulation source. Furthermore, MEPs thresholds were highly accurate to exclude the occurrence of postoperative capsular side effects. Conclusions Intraoperative MEPs provide additional targeting guidance, especially in asleep DBS surgery, where clinical value of microelectrode recordings and test stimulation may be limited. As this technique can exclude future capsular side effects, it can directly be translated into clinical practice.

Purpose: The ventral intermediate nucleus (VIM) of the thalamus is the typical target of deep brain stimulation (DBS) for controlling tremor in essential tremor (ET). It remains unclear whether the outcomes are significantly different on speech and/or swallowing functions. This study was to compare speech and swallowing outcomes in patients with ET without VIM DBS, and those with unilateral/bilateral VIM DBS.Methods: We conducted a retrospective review of 133 patients with the diagnosis of ET. We analyzed the clinical speech and swallowing evaluations, and compared outcomes across four ‘DBS disposition’ groupings: no DBS, left, right, or bilateral VIM DBS.Results: Speech function was worse in bilateral group versus no DBS and unilateral groups. Orofacial (p=0.000), rate (p=0.001), and prosody (p=0.003) were significantly different between groups. No DBS and unilateral groups demonstrated either no dysarthria or mild hyperkinetic dysarthria versus exhibiting higher rates of dysarthria including an ataxic component in bilateral group. Bilateral group showed more impaired swallowing severity versus no DBS and unilateral groups, however, these differences were not statistically significant.Conclusions: The results demonstrated speech and swallowing changes in the ET patient population after VIM DBS. This data provides support for further study in order to better understand the speech and/or swallowing changes that may occur with VIM DBS.

Background and purpose Quantitative susceptibility mapping (QSM) has been shown to be valuable in direct targeting for subthalamic nucleus (STN) DBS, given its higher quality of contrast between the STN border and adjacent anatomical structures. The objective is to demonstrate the feasibility of using 1.5 T QSM for direct targeting in STN DBS planning. Material and methods Eleven patients underwent MRI acquisitions using a 1.5 T scanner, including multi-echo gradient echo sequences for generating QSM images. 22 STN targets were planned with direct targeting method using QSM images by one stereotactic neurosurgeon and indirect targeting method using standard protocol by a second stereotactic neurosurgeon. The two physicians were blinded to each other's results. Results The mean coordinates for the STN using direct targeting relative to the mid-commissural point (MCP) was 11.41 ± 2.43 mm lateral, 2.48 ± 0.53 mm posterior and 4.45 ± 0.95 mm inferior. The mean coordinates for the STN using indirect targeting was 11.79 ± 2.51 mm lateral, 2.55 ± 0.54 mm posterior, and 4.84 ± 1.03 mm inferior. The mean (±SEM) radial error between the direct and indirect target was 0.67 ± 0.14 mm. In cases where DBS electrodes were implanted, the radial difference between the indirect and actual target (1.19 ± 0.30 mm) was statistically equivalent to the radial difference between the direct and actual target (1.0 ± 0.27 mm). Conclusions Direct targeting of the STN for DBS implantation using 1.5 T QSM was found to be statistically equivalent to standard protocol surgery planning. This may offer a simpler, more intuitive alternative for DBS surgery planning at centers with 1.5 T MRIs.

Hemorrhagic venous infarction secondary to deep brain stimulation (DBS) surgery occurs rarely and can cause delayed intracranial hemorrhage. Venous cerebral infarction after DBS surgery is commonly caused by coagulation of the superficial cerebral veins, which usually produces transient symptoms but leaves no permanent sequelae. We report a case of hemorrhagic venous infarction resulting in severe sequelae, likely due to coagulation of the lateral venous lacuna during DBS surgery.

OBJECTIVEThe goal of this study was to demonstrate the use of quantitative susceptibility mapping (QSM)–based images to precisely localize the globus pallidus internus (GPi) for deep brain stimulation (DBS) planning and to enhance postsurgical visualization of the DBS lead positions.METHODSPresurgical T1-weighted (T1w), T2-weighted (T2w), and QSM images as well as postsurgical CT images were obtained in 29 patients with Parkinson’s disease. To enhance the contrast within the GP, a hybrid contrast was created by linearly combining T1w and QSM images. Contrast-to-noise ratios (CNRs) of the GPi on T1w, T2w, QSM, and hybrid images were compared. The CNR differences were tested using the 1-way ANOVA method. The visualization of the DBS lead position was demonstrated by merging the postsurgical CT with presurgical MR images.RESULTSThe hybrid images yield the best CNRs for GPi depiction and the visualization of the postsurgical DBS lead position was significantly improved.CONCLUSIONSQSM-based images allow for confident localization of borders of the GPi that is superior to T1w and T2w images. High-contrast hybrid images can be used for precisely directed DBS targeting, e.g., GPi DBS for the treatment of advanced Parkinson’s disease.

Background Hemophilia is generally considered a contraindication to deep brain stimulation (DBS) and other elective intracranial surgery because of the elevated risk of perioperative hemorrhage. Two prior case reports have suggested, however, that DBS may be safe in patients with hemophilia who undergo appropriate factor replacement. Here, we describe a third case of DBS surgery for medically refractory essential tremor (ET) in a patient with hemophilia A. Case Description A 68-year-old right-handed man with mild hemophilia A presented for a 10-year history of bilateral (right greater than left), medically refractory ET. The patient was considered an appropriate candidate for DBS by a multidisciplinary movement disorders conference, and hematology consultation was obtained. Baseline preoperative laboratory results showed a quantitative factor VIII (FVIII) level of 38%. Perioperative management consisted of daily intravenous bolus doses of recombinant FVIII from the morning of surgery to postoperative day 10. The patient underwent uncomplicated unilateral DBS placement in the left ventralis intermedius thalamus. Intra- and postoperative imaging showed no hemorrhage. His postoperative course was uncomplicated except for a single self-limited episode of hematuria requiring no intervention. Conclusions DBS placement for ET may be safe in patients with coexisting hemophilia A if appropriate FVIII replacement is given, which may be delivered as bolus infusions rather than continuous infusion.

AIM: To examine the postoperative outcomes of electrode fixation using bone cement and Stimloc® in patients with Parkinson’s disease (PD) who underwent subthalamic nucleus (STN) deep brain stimulation (DBS). MATERIAL and METHODS: Between 2016 and 2018, permanent electrode fixation was performed in 30 patients with PD, of which 15 received bone cement and the remaining 15 received Stimloc®. Data regarding preoperative Unified Parkinson’s Disease Rating Scale (UPDRS) III scores, levodopa equivalent daily dose (LEDD) values, surgery duration, and the fixation technique used were recorded. Brain computed tomography was performed for early postoperative evaluation of pneumocephalus and possible hematoma as well as for the determination of migration 1 year postoperatively. UPDRS III scores and LEDD values were re-evaluated 1 year postoperatively; surgery duration, clinical effectiveness, and complication rates were compared between the two fixation techniques. RESULTS: A statistically significant difference in application time was observed between the two techniques (bone cement: 21 min, Stimloc®: 6 min). After 1 year from surgery, 0.92- and 0.88-mm migrations were observed in the bone cement and Stimloc® groups, respectively. A significant correlation between migration and the pneumocephalus volume was observed in both groups. No differences were observed between the groups regarding infection, migration, pneumocephalus volume, wound erosion, and clinical outcomes. CONCLUSION: Stimloc® is preferred over bone cement for electrode fixation in DBS surgeries as it is associated with shorter application duration; this increases patient comfort and tolerance during awake surgery. Clinical efficacy and complication rates associated with both techniques are similar.

Deep brain stimulation (DBS) electrode implant trajectories are stereotactically defined using preoperative neuroimaging. To validate the correct trajectory, microelectrode recordings (MERs) or local field potential recordings can be used to extend neuroanatomical information (defined by MRI) with neurophysiological activity patterns recorded from micro- and macroelectrodes probing the surgical target site. Currently, these two sources of information (imaging vs. electrophysiology) are analyzed separately, while means to fuse both data streams have not been introduced.Here, we present a tool that integrates resources from stereotactic planning, neuroimaging, MER, and high-resolution atlas data to create a real-time visualization of the implant trajectory. We validate the tool based on a retrospective cohort of DBS patients (N = 52) offline and present single-use cases of the real-time platform.We establish an open-source software tool for multimodal data visualization and analysis during DBS surgery. We show a general correspondence between features derived from neuroimaging and electrophysiological recordings and present examples that demonstrate the functionality of the tool.This novel software platform for multimodal data visualization and analysis bears translational potential to improve accuracy of DBS surgery. The toolbox is made openly available and is extendable to integrate with additional software packages.Deutsche Forschungsgesellschaft (410169619, 424778381), Deutsches Zentrum für Luft- und Raumfahrt (DynaSti), National Institutes of Health (2R01 MH113929), and Foundation for OCD Research (FFOR).Deep brain stimulation is an established therapy for patients with Parkinson’s disease and an emerging option for other neurological conditions. Electrodes are implanted deep in the brain to stimulate precise brain regions and control abnormal brain activity in those areas. The most common target for Parkinson’s disease, for instance, is a structure called the subthalamic nucleus, which sits at the base of the brain, just above the brain stem. To ensure electrodes are placed correctly, surgeons use various sources of information to characterize the patient’s brain anatomy and decide on an implant site. These data include brain scans taken before surgery and recordings of brain activity taken during surgery to confirm the intended implant site. Sometimes, the brain activity signals from this last confirmation step may slightly alter surgical plans. It represents one of many challenges for clinical teams: to analyse, assimilate, and communicate data as it is collected during the procedure. Oxenford et al. developed a software pipeline to aggregate the data surgeons use to implant electrodes. The open-source platform, dubbed Lead-OR, visualises imaging data and brain activity recordings (termed electrophysiology data) in real time. The current set-up integrates with commercial tools and existing software for surgical planning. Oxenford et al. tested Lead-OR on data gathered retrospectively from 32 patients with Parkinson’s who had electrodes implanted in their subthalamic nucleus. The platform showed good agreement between imaging and electrophysiology data, although there were some unavoidable discrepancies, arising from limitations in the imaging pipeline and from the surgical procedure. Lead-OR was also able to correct for brain shift, which is where the brain moves ever so slightly in the skull. With further validation, this proof-of-concept software could serve as a useful decision-making tool for surgical teams implanting electrodes for deep brain stimulation. In time, if implemented, its use could improve the accuracy of electrode placement, translating into better surgical outcomes for patients. It also has the potential to integrate forthcoming ultra-high-resolution data from current brain mapping projects, and other commercial surgical planning tools.

Background: Symptomatic pneumocephalus is an uncommon complication of cranial surgery. Reports of symptomatic pneumocephalus in deep brain stimulation (DBS) surgery are lacking, due to the rarity of this condition. The ­authors describe 2 patients who experienced clinically significant intraparenchymal pneumocephalus as a consequence of DBS surgery and report their clinical presentations, treatments, and outcomes. Cases Descriptions: The first patient was a 69-year-old woman with Parkinson disease and the second was a 73-year-old woman with medically refractory essential tremor. Both patients underwent DBS implantation and developed focal neurological deficits in the days after surgery. In each case, immediate postoperative head computed tomography scans showed extra-axial pneumocephalus which redistributed on subsequent imaging along the dorsal length of the lead. For each patient, a second surgery was carried out to evacuate the pneumocephalus without lead removal. Clinical symptoms and radiological signs of intracranial air were resolved on the last follow-up. Conclusion: Symptomatic intraparenchymal pneumocephalus is a rare complication of DBS surgery which can be treated with surgical evacuation.

Essential tremor (ET) is a disabling movement disorder that is most prevalent among the elderly. While deep brain stimulation surgery targeting the ventral intermediate nucleus of the thalamus is commonly used to treat ET, the most elderly patients or those with multiple medical comorbidities may not qualify as surgical candidates. Magnetic resonance-guided focused ultrasound (MRgFUS) constitutes a less invasive modality that may be used to perform thalamotomy without the need for a burr hole craniotomy. Here, we report on 2 patients over the age of 90 years who benefited significantly from MRgFUS thalamotomy to relieve their symptoms and improve their quality of life. The procedure was well tolerated and performed safely in both patients. We conclude that age should not be a limiting factor in the treatment of patients with MRgFUS.

뇌심부자극술은 뇌심부핵에 고주파 전기자극을 전달하여 약물 불응성 이상운동질환을 치료하는 효과적인 방법이다. 그리고 미세전극기록은 뇌심부자극 수술 중에 MRI와 함께 뇌심부핵의 위치를 정확히 파악하여 수술 결과를 향상시키고 부작용을 최소화 할 수 있는 보조적인 검사이다. 본 논문의 목적은 이상운동질환에 대한 뇌심부자극 수술 중에 실시한 미세전극기록을 분석하여 신경생리학적 파형과 유용성을 알아보고자 하였다. 2018년 1월부터 12월까지 이상운동질환에 대한 뇌심부자극수술 중에 미세전극기록를 실시한 환자 대상으로 후향적 조사를 하였다. 총 28명의 환자 중에 시상하핵은 38 개의 MER, 내측 담창구는 10개의 MER, 복내측 시상핵은 4개의 MER을 실시했다. 모두 목표지점을 찾았고 미세자극을 이용해서 부작용의 여부를 확인하고 목표지점을 재조정하였다. 수술 후 총 28명의 환자에서 모두 임상 증상은 호전되었다. 결론적으로. 미세전극기록은 신경생리학적 파형을 이용해서 MRI와 함께 정확한 뇌심부핵 부위를 파악해서 이상운동질환에 대한 뇌심부자극 수술 결과를 향상시키고 부작용을 최소화할 수 있는 유용한 검사이다.

Background Efficacy in deep brain stimulation (DBS) is dependent on precise positioning of electrodes within the brain. Intraoperative fluoroscopy, computed tomography (CT), or magnetic resonance imaging are used for stereotactic intraoperative localization (StIL), but the utility of biplanar X-ray has not been evaluated in detail. Objective To determine if analysis of orthogonal biplanar X-rays using graphical analysis (GA), ray tracing (RT), and/or perspective projection (PP) can be utilized for StIL. Methods A review of electrode tip positions comparing postoperative CT to X-ray methods was performed for DBS operations containing orthogonal biplanar X-ray with referential spheres and pins. Results Euclidean (Re) errors for final DBS electrode position on intraoperative X-rays vs postoperative CT using GA, RT, and PP methods averaged 1.58 mm (±0.75), 0.74 mm (±0.45), and 1.07 mm (±0.64), respectively (n = 56). GA was more accurate with a ventriculogram. RT and PP predicted positions that correlated with third ventricular structures on ventriculogram cases. RT was the most stable but required knowledge of the geometric setup. PP was more flexible than RT but required well-distributed reference points. A single case using the O-arm demonstrated Re errors of 0.43 mm and 0.28 mm for RT and PP, respectively. In addition, these techniques could also be used to calculate directional electrode rotation. Conclusion GA, RT, and PP can be employed for precise StIL during DBS using orthogonal biplanar X-ray. These methods may be generalized to other stereotactic procedures or instances of biplanar imaging such as angiograms, radiosurgery, or injection therapeutics.

Background Deep brain stimulation (DBS) surgery in patients with pre-existing cochlear implants (CIs) poses various challenges. We previously reported successful magnetic resonance imaging (MRI)-based, microelectrode recording (MER)-guided subthalamic DBS surgery in a patient with a pre-existing CI. Other case reports have described various DBS procedures in patients with pre-existing CIs using different techniques, leading to varying issues to address. A standardized operative technique and workflow for DBS surgery in the setting of pre-existing CIs is much needed. Objective To provide a standardized operative technique and workflow for DBS lead placement in the setting of pre-existing CIs. Methods Our operative technique is MRI-based and MER-guided, following a workflow involving coordination with a neurotology team to remove and re-implant the internal magnets of the CIs in order to safely perform DBS lead placement, altogether within a 24-h time frame. Intraoperative nonverbal communication with the patient is easily possible using a computer monitor. Results A 65-yr old woman with a 10-yr history of craniocervical dystonia and pre-existing bilateral CIs underwent successful bilateral pallidal DBS surgery at our institution. No merging errors or difficulties in targeting globus pallidus internus were experienced. Also, inactivated CIs do not interfere with MER nor with stimulation, and intraoperative communication with the patient using a computer monitor proved feasible and satisfactory. Conclusion DBS procedures are safe and feasible in patients with pre-existing CIs if precautions are taken following our workflow.

Background The goal of deep brain stimulation (DBS) is to achieve maximal benefit for the patient while minimizing the likelihood of adverse effects. Currently, no standardized criteria exist that predicts extended hospital stay in DBS patients, although careful patient selection is recognized as a very important step for successful DBS therapy. Objectives and Methods The objective of this study was to identify eight key factors that predicted extended post-operative hospital stay following DBS lead implantation, in an effort to better identify patients that would require minimal hospital stay, resulting in reduced cost and reduced exposure to hospital- related problems. Univariate logistic regression models were used to examine associations between each factor and patients’ post-surgical outcomes. Results Using data collected from 183 patients, we found that 53 patients required a hospital stay longer than two days within one month post-procedure. Those who were 70 years or older and those who had frequent falls were significantly more likely to require extended post-surgical care. Patients that scored three points or higher on our eight-factor assessment scale had a greater likelihood of experiencing an event that would require an extended hospital stay following DBS lead placement, regardless of what three factors were present. Conclusions Any PD patient who is 70 years or older, incurring frequent falls, or with more than three points on our scale, should be carefully screened and cautioned about likely prolonged recovery and extended post-operative hospital stay.

Diffuse reflectance spectroscopy (or DRS) is a technique where the absorption and scattering characteristics of a given material are inferred from the reflectes spectra, typically in the visible and near-infrared regions. It has been used to study biological tissue in a wide range of studies from cancer detection to neurovasculature dynamics. Its simplicity and good potential to identify tissue in the brain has brought us to use it for neurosurgical guidance. We show that DRS can give blood content information due to the strong absorbers in blood deoxygenated and oxygenated hemoglobin, but most importantly, thanks to the difference in myelinated and unmyelinated axons scattering properties, it can distinguish between white and grey matter content in live tissue. We demonstrate its use in fixed and live tissues and how we plan on using the information for surgical guidance during deep brain stimulation surgery.