Diffusion tensor imaging in pediatric patients with dystonia.

BACKGROUND: Childhood-onset dystonia is often progressive and severely impairs a child´s life. The pathophysiology is very heterogeneous and treatment responses vary in patients with dystonia. Factors influencing treatment effects remain to be elucidated. We hypothesize that differences in brain connectivity and fiber coherence contribute to the heterogeneity in treatment response among pediatric patients with inherited and acquired dystonia. METHODS: Twenty patients with childhood-onset dystonia were retrospectively recruited including twelve patients with inherited or idiopathic, and eight patients with acquired dystonia (mean age 10 years; 8 female/12 male). Fiber density between the internal part of the globus pallidus and selective target regions, as well as the diffusion measures of fractional anisotropy (FA) and mean diffusivity (MD) were analyzed and compared between different etiologies. RESULTS: Patients with acquired dystonia presented higher fiber density to the premotor cortex and putamen and lower FA values in the thalamus compared to patients with inherited/idiopathic dystonia. MD in the premotor cortex was higher in patients with acquired dystonia, while it was lower in the thalamus. CONCLUSION: Diffusion MRI reveals microstructural and network alterations in patients with dystonia of different etiologies.

General Algorithm Applicability in Determining DBS Lead Orientation: Adapting 2D and 3D X-Ray Techniques for SenSightTM Leads.

INTRODUCTION: With recent advancements in deep brain stimulation (DBS), directional leads featuring segmented contacts have been introduced, allowing for targeted stimulation of specific brain regions. Given that manufacturers employ diverse markers for lead orientation, our investigation focuses on the adaptability of the 2017 techniques proposed by the Cologne research group for lead orientation determination. METHODS: We tailored the two separate 2D and 3D X-ray-based techniques published in 2017 and originally developed for C-shaped markers, to the dual-marker of the Medtronic SenSight™ lead. In a retrospective patient study, we evaluated their feasibility and consistency by comparing the degree of agreement between the two methods. RESULTS: The Bland-Altman plot showed favorable concordance without any noticeable systematic errors. The mean difference was 0.79°, with limits of agreement spanning from 21.4° to -19.8°. The algorithms demonstrated high reliability, evidenced by an intraclass correlation coefficient of 0.99 (p < 0.001). CONCLUSION: The 2D and 3D algorithms, initially formulated for discerning the circular orientation of a C-shaped marker, were adapted to the marker of the Medtronic SenSight™ lead. Statistical analyses revealed a significant level of agreement between the two methods. Our findings highlight the adaptability of these algorithms to different markers, achievable through both low-dose intraoperative 2D X-ray imaging and standard CT imaging.

Incidence and Management of Hardware-Related Wound Infections in Spinal Cord, Peripheral Nerve Field, and Deep Brain Stimulation Surgery: A Single-Center Study.

INTRODUCTION: Neuromodulation using deep brain stimulation (DBS), spinal cord stimulation (SCS), and peripheral nerve field stimulation (PNFS) to treat neurological, psychiatric, and pain disorders is a rapidly growing field. Infections related to the implanted hardware are among the most common complications and result in health-related and economic burden. Unfortunately, conservative medical therapy is less likely to be successful. In this retrospective study, we aimed to identify characteristics of the infections and investigated surgical and antimicrobial treatments. METHODS: A retrospective analysis was performed of patients with an infection related to DBS, SCS, and/or PNFS hardware over an 8-year period at our institution. Data were analyzed for type of neurostimulator, time of onset of infection following the neurosurgical procedure, location, and surgical treatment strategy. Surgical treatment of infections consisted of either a surgical wound revision without hardware removal or a surgical wound revision with partial or complete hardware removal. Data were further analyzed for the microorganisms involved, antimicrobial treatment and its duration, and clinical outcome. RESULTS: Over an 8-year period, a total of 1,250 DBS, 1,835 SCS, and 731 PNFS surgeries were performed including de novo system implantations, implanted pulse generator (IPG) replacements, and revisions. We identified 82 patients with infections related to the neurostimulator hardware, representing an incidence of 3.09% of the procedures. Seventy-one percent of the patients had undergone multiple surgeries related to the neurostimulator prior to the infection. The infections occurred after a mean of 12.2 months after the initial surgery. The site of infection was most commonly around the IPG, especially in DBS and SCS. The majority (62.2%) was treated by surgical wound revision with simultaneous partial or complete removal of hardware. Microbiological specimens predominantly yielded Staphylococcus epidermidis (39.0%) and Staphylococcus aureus (35.4%). After surgery, antimicrobials were given for a mean of 3.4 weeks. The antimicrobial regime was significantly shorter in patients with hardware removal in comparison to those who only had undergone surgical wound revision. One intracranial abscess occurred. No cases of infection-related death, sepsis, bacteremia, or intraspinal abscesses were found. CONCLUSION: Our data did show the predominance of S. epidermidis and S. aureus as etiologic organisms in hardware-related infections. Infections associated with S. aureus most likely required (partial) hardware removal. Aggressive surgical treatment including hardware removal shortens the duration of antimicrobial treatment. Clear strategies should be developed to treat hardware-related infections to optimize patient management and reduce health- and economic-related burden.

Automatic Detection of Directional Lead Orientation in Deep Brain Stimulation using Photon-Counting Detector Computed Tomography: A Phantom Study.

INTRODUCTION: Photon-counting detector computed tomography (PCD-CT) represents the next generation of CT technology, offering enhanced capabilities for detecting the orientation of directional leads in deep brain stimulation (DBS). This study aims to refine PCD-CT-based lead orientation determination using an automated method applicable to devices from various manufacturers, addressing current methodological limitations and improving neurosurgical precision. METHODS: An automated method was developed to ascertain the orientation of directional DBS leads using PCD-CT data and grayscale model fitting for devices from Boston Scientific, Medtronic, and Abbott. A phantom study was conducted to evaluate the precision and accuracy of this method, comparing it with the stripe artifact method across different lead alignments relative to the CT gantry axis. RESULTS: Except for the Medtronic Sensight™ lead, where detection was occasionally unfeasible if aligned normal to the z-axis of the CT gantry, a clinically very unlikely alignment, the lead orientation could be automatically determined regardless of its position. The accuracy and precision of this automated method was comparable to those of the stripe artifact method. CONCLUSION: PCD-CT enables the automatic determination of lead orientation from leading manufacturers with an accuracy comparable to the stripe artifact method, and it offers the added benefit of being independent of the clinically occurring orientation of the head and, consequently, the lead relative to the CT gantry axis.

Quality of Life After Deep Brain Stimulation of Pediatric Patients with Dyskinetic Cerebral Palsy: A Prospective, Single-Arm, Multicenter Study with a Subsequent Randomized Double-Blind Crossover (STIM-CP).

BACKGROUND: Patients with dyskinetic cerebral palsy are often severely impaired with limited treatment options. The effects of deep brain stimulation (DBS) are less pronounced than those in inherited dystonia but can be associated with favorable quality of life outcomes even in patients without changes in dystonia severity. OBJECTIVE: The aim is to assess DBS effects in pediatric patients with pharmacorefractory dyskinetic cerebral palsy with focus on quality of life. METHODS: The method used is a prospective, single-arm, multicenter study. The primary endpoint is improvement in quality of life (CPCHILD [Caregiver Priorities & Child Health Index of Life with Disabilities]) from baseline to 12 months under therapeutic stimulation. The main key secondary outcomes are changes in Burke-Fahn-Marsden Dystonia Rating Scale, Dyskinesia Impairment Scale, Gross Motor Function Measure-66, Canadian Occupational Performance Measure (COPM), and Short-Form (SF)-36. After 12 months, patients were randomly assigned to a blinded crossover to receive active or sham stimulation for 24 hours each. Severity of dystonia and chorea were blindly rated. Safety was assessed throughout. The trial was registered at ClinicalTrials.gov, number NCT02097693. RESULTS: Sixteen patients (age: 13.4 ± 2.9 years) were recruited by seven clinical sites. Primary outcome at 12-month follow-up is as follows: mean CPCHILD increased by 4.2 ± 10.4 points (95% CI [confidence interval] -1.3 to 9.7; P = 0.125); among secondary outcomes: improvement in COPM performance measure of 1.1 ± 1.5 points (95% CI 0.2 to 1.9; P = 0.02) and in the SF-36 physical health component by 5.1 ± 6.2 points (95% CI 0.7 to 9.6; P = 0.028). Otherwise, there are no significant changes. CONCLUSION: Evidence to recommend DBS as routine treatment to improve quality of life in pediatric patients with dyskinetic cerebral palsy is not yet sufficient. Extended follow-up in larger cohorts will determine the impact of DBS further to guide treatment decisions in these often severely disabled patients. © 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Temporal Stability of Lead Orientation in Directional Deep Brain Stimulation.

BACKGROUND: Directional deep brain stimulation (DBS) enlarges the therapeutic window by increasing side-effect thresholds and improving clinical benefits. To determine the optimal stimulation settings and interpret clinical observations, knowledge of the lead orientation in relation to the patient's anatomy is required. OBJECTIVE: To determine if directional leads remain in a fixed orientation after implantation or whether orientation changes over time. METHOD: Clinical records of 187 patients with directional DBS electrodes were screened for CT scans in addition to the routine postoperative CT. The orientation angle of each electrode at a specific point in time was reconstructed from CT artifacts using the DiODe algorithm implemented in Lead-DBS. The orientation angles over time were compared with the originally measured orientations from the routine postoperative CT. RESULTS: Multiple CT scans were identified in 18 patients and the constancy of the orientation angle was determined for 29 leads at 48 points in time. The median time difference between the observations and the routine postoperative CT scan was 82 (range 1-811) days. The mean difference of the orientation angles compared to the initial measurement was -1.1 ± 3.9° (range -7.6 to 8.7°). Linear regression showed no relevant drift of the absolute value of the orientation angle over time (0.8°/year, adjusted R2: 0.040, p = 0.093). CONCLUSION: The orientation of directional leads was stable and showed no clinically relevant changes either in the first weeks after implantation or over longer periods of time.

Potentials and Limitations of Directional Deep Brain Stimulation: A Simulation Approach.

BACKGROUND: Directional leads are increasingly used in deep brain stimulation. They allow shaping the electrical field in the axial plane. These new possibilities increase the complexity of programming. Thus, optimized programming approaches are needed to assist clinical testing and to obtain full clinical benefit. OBJECTIVES: This simulation study investigates to what extent the electrical field can be shaped by directional steering to compensate for lead malposition. METHOD: Binary volumes of tissue activated (VTA) were simulated, by using a finite element method approach, for different amplitude distributions on the three directional electrodes. VTAs were shifted from 0 to 2 mm at different shift angles with respect to the lead orientation, to determine the best compensation of a target volume. RESULTS: Malpositions of 1 mm can be compensated with the highest gain of overlap with directional leads. For larger shifts, an improvement of overlap of 10-30% is possible, depending on the stimulation amplitude and shift angle of the lead. Lead orientation and shift determine the amplitude distribution of the electrodes. CONCLUSION: To get full benefit from directional leads, both the shift angle as well as the shift to target volume are required to choose the correct amplitude distribution on the electrodes. Current directional leads have limitations when compensating malpositions >1 mm; however, they still outperform conventional leads in reducing overstimulation. Further, their main advantage probably lies in the reduction of side effects. Databases like the one from this simulation could serve for optimized lead programming algorithms in the future.

A functional micro-electrode mapping of ventral thalamus in essential tremor.

Deep brain stimulation enables the delivery of therapeutic interventions to otherwise inaccessible areas of the brain while, at the same time, offering the unique opportunity to record from these same regions in awake patients. The posterior ventrolateral thalamus has become a reliable deep brain stimulation target for medically-refractory patients suffering from essential tremor. However, the contribution of the thalamus in essential tremor, and even whether posterior ventrolateral thalamus is the optimal target, remains a matter of ongoing debate. There are several lines of evidence supporting clusters of activity within the posterior ventrolateral thalamus that are important for tremor emergence. In this study we sought to map the functional properties of these clusters through microelectrode recordings during deep brain stimulation surgery. Data were obtained from 10 severely affected patients with essential tremor (12 hemispheres) undergoing deep brain stimulation surgery. Our results demonstrate power and coherence maxima located in the inferior posterior ventrolateral thalamus and immediate ventral region. Moreover, we identified distinct yet overlapping clusters of predominantly efferent (driving) and afferent (feedback) activity, with a preference for more efferent contributors, consistent with a net role in the driving of tremor output. Finally, we demonstrate that resolvable thalamic spiking activity directly relates to background activity and that the strength of tremor may be dictated by phase relationships between efferent and afferent pockets in the posterior ventrolateral thalamus. Taken together, these results provide important evidence for the role of the inferior posterior ventrolateral thalamus and its border region in essential tremor pathophysiology. Such results progress our mechanistic understanding and promote the adoption of next-generation therapies such as high resolution segregated deep brain stimulation electrodes.

DiODe: Directional Orientation Detection of Segmented Deep Brain Stimulation Leads: A Sequential Algorithm Based on CT Imaging.

BACKGROUND: Directional deep brain stimulation (DBS) allows steering the stimulation in an axial direction which offers greater flexibility in programming. However, accurate anatomical visualization of the lead orientation is required for interpreting the observed stimulation effects and to guide programming. OBJECTIVES: In this study we aimed to develop and test an accurate and robust algorithm for determining the orientation of segmented electrodes based on standard postoperative CT imaging used in DBS. METHODS: Orientation angles of directional leads (CartesiaTM; Boston Scientific, Marlborough, MA, USA) were determined using CT imaging. Therefore, a sequential algorithm was developed that quantitatively compares the similarity of the observed CT artifacts with calculated artifact patterns based on the lead's orientation marker and a geometric model of the segmented electrodes. Measurements of seven ground truth phantoms and three leads with 60 different configurations of lead implantation and orientation angles were analyzed for validation. RESULTS: The accuracy of the determined electrode orientation angles was -0.6 ± 1.5° (range: -5.4 to 4.2°). This accuracy proved to be sufficiently high to resolve even subtle differences between individual leads. CONCLUSIONS: The presented algorithm is user independent and provides highly accurate results for the orientation of the segmented electrodes for all angular constellations that typically occur in clinical cases.

Directional DBS increases side-effect thresholds-A prospective, double-blind trial.

OBJECTIVE: The objective of this study was to investigate whether directional deep brain stimulation (DBS) of the subthalamic nucleus in Parkinson's disease (PD) offers increased therapeutic windows, side-effect thresholds, and clinical benefit. METHODS: In 10 patients, 20 monopolar reviews were conducted in a prospective, randomized, double-blind design to identify the best stimulation directions and compare them to conventional circular DBS regarding side-effect thresholds, motor improvement, and therapeutic window. In addition, circular and best-directional DBS were directly compared in a short-term crossover. Motor outcome was also assessed after an open-label follow-up of 3 to 6 months. RESULTS: Stimulation in the individual best direction resulted in significantly larger therapeutic windows, higher side-effect thresholds, and more improvement in hand rotation than circular DBS. Rigidity and finger tapping did not respond differentially to the stimulation conditions. There was no difference in motor efficacy or stimulation amplitudes between directional and circular DBS in the short-term crossover. Follow-up evaluations 3 to 6 months after implantation revealed improvements in motor outcome and medication reduction comparable to other DBS studies with a majority of patients remaining with a directional setting. CONCLUSION: Directional DBS can increase side-effect thresholds while achieving clinical benefit comparable to conventional DBS. Whether directional DBS improves long-term clinical outcome needs to be investigated in the future. © 2017 International Parkinson and Movement Disorder Society.

The Effect of Uni- and Bilateral Thalamic Deep Brain Stimulation on Speech in Patients With Essential Tremor: Acoustics and Intelligibility.

BACKGROUND: Deep brain stimulation (DBS) of the ventral intermediate nucleus (VIM) is performed to suppress medically-resistant essential tremor (ET). However, stimulation induced dysarthria (SID) is a common side effect, limiting the extent to which tremor can be suppressed. To date, the exact pathogenesis of SID in VIM-DBS treated ET patients is unknown. OBJECTIVE: We investigate the effect of inactivated, uni- and bilateral VIM-DBS on speech production in patients with ET. We employ acoustic measures, tempo, and intelligibility ratings and patient's self-estimated speech to quantify SID, with a focus on comparing bilateral to unilateral stimulation effects and the effect of electrode position on speech. METHODS: Sixteen German ET patients participated in this study. Each patient was acoustically recorded with DBS-off, unilateral-right-hemispheric-DBS-on, unilateral-left-hemispheric-DBS-on, and bilateral-DBS-on during an oral diadochokinesis task and a read German standard text. To capture the extent of speech impairment, we measured syllable duration and intensity ratio during the DDK task. Naïve listeners rated speech tempo and speech intelligibility of the read text on a 5-point-scale. Patients had to rate their "ability to speak". RESULTS: We found an effect of bilateral compared to unilateral and inactivated stimulation on syllable durations and intensity ratio, as well as on external intelligibility ratings and patients' VAS scores. Additionally, VAS scores are associated with more laterally located active contacts. For speech ratings, we found an effect of syllable duration such that tempo and intelligibility was rated worse for speakers exhibiting greater syllable durations. CONCLUSION: Our data confirms that SID is more pronounced under bilateral compared to unilateral stimulation. Laterally located electrodes are associated with more severe SID according to patient's self-ratings. We can confirm the relation between diadochokinetic rate and SID in that listener's tempo and intelligibility ratings can be predicted by measured syllable durations from DDK tasks.

Intracranial stereotactic radiosurgery with an adapted linear accelerator vs. robotic radiosurgery: Comparison of dosimetric treatment plan quality.

BACKGROUND AND PURPOSE: Stereotactic radiosurgery with an adapted linear accelerator (linac-SRS) is an established therapy option for brain metastases, benign brain tumors, and arteriovenous malformations. We intended to investigate whether the dosimetric quality of treatment plans achieved with a CyberKnife (CK) is at least equivalent to that for linac-SRS with circular or micromultileaf collimators (microMLC). PATIENTS AND METHODS: A random sample of 16 patients with 23 target volumes, previously treated with linac-SRS, was replanned with CK. Planning constraints were identical dose prescription and clinical applicability. In all cases uniform optimization scripts and inverse planning objectives were used. Plans were compared with respect to coverage, minimal dose within target volume, conformity index, and volume of brain tissue irradiated with ≥ 10 Gy. RESULTS: Generating the CK plan was unproblematic with simple optimization scripts in all cases. With the CK plans, coverage, minimal target volume dosage, and conformity index were significantly better, while no significant improvement could be shown regarding the 10 Gy volume. Multiobjective comparison for the irradiated target volumes was superior in the CK plan in 20 out of 23 cases and equivalent in 3 out of 23 cases. Multiobjective comparison for the treated patients was superior in the CK plan in all 16 cases. CONCLUSION: The results clearly demonstrate the superiority of the irradiation plan for CK compared to classical linac-SRS with circular collimators and microMLC. In particular, the average minimal target volume dose per patient, increased by 1.9 Gy, and at the same time a 14% better conformation index seems to be an improvement with clinical relevance.

Video-Guided Optimization of Stimulation Settings in Patients with Parkinson's Disease and Deep Brain Stimulation.

Deep brain stimulation (DBS) for Parkinson's disease (PD) often necessitates frequent clinic visits for stimulation program optimization, with limited experience in remote patient management. Due to the resource-intensive nature of these procedures, we investigated a way to simplify stimulation optimization for these patients that allows for the continuous monitoring of symptoms while also reducing patient burden and travel distances. To this end, we prospectively recruited ten patients treated with DBS for PD to evaluate the feasibility of telemedicinal optimization in a home-based setting. Patients recorded daily videos of a modified Unified Parkinson's Disease Rating Scale (UPDRS) III, which experienced DBS physicians located at the clinic assessed to provide instructions on adjusting stimulation settings using a handheld programmer with previously set programs as well as patient amplitude control. This study concluded with significant improvements in participants' motor status as measured by the UPDRS-III (p = 0.0313) compared to baseline values. These findings suggest that remote video-guided optimization of DBS settings is feasible and may enhance motor outcomes for patients.

Pallidal deep brain stimulation in a patient with nonketotic hyperglycemic hemichorea.

Background: Hyperkinetic movement disorders secondary to brain tissue damage due to hyperglycemia are a rare complication of diabetes mellitus. Nonketotic hyperglycemic hemichorea (NH-HC) is characterized by a rapid onset of involuntary movements after increased serum glucose levels. Case Description: We report on a case of a 62-year-old male patient with a 28-year history of Type II diabetes mellitus with NH-HC following an infect-associated exacerbation of blood glucose levels. Choreiform movements of the right upper extremity, face, and trunk persisted 6 months after onset. Due to failure of conservative treatments, we opted for unilateral deep brain stimulation of the globus pallidus internus, which led to complete cessation of symptoms within a week after initial programming. Symptom control was still satisfactory 12 months after surgery. No side-effects or surgery-associated complications were observed. Conclusion: Globus pallidus internus DBS is an effective and safe treatment option for hyperkinetic movement disorders secondary to brain tissue damage caused by hyperglycemia. Postoperatively, stimulation effects can be observed quickly and effects persist even after 12 months.

Neuroimaging-based analysis of DBS outcomes in pediatric dystonia: Insights from the GEPESTIM registry.

INTRODUCTION: Deep brain stimulation (DBS) is an established treatment in patients of various ages with pharmaco-resistant neurological disorders. Surgical targeting and postoperative programming of DBS depend on the spatial location of the stimulating electrodes in relation to the surrounding anatomical structures, and on electrode connectivity to a specific distribution pattern within brain networks. Such information is usually collected using group-level analysis, which relies on the availability of normative imaging resources (atlases and connectomes). Analysis of DBS data in children with debilitating neurological disorders such as dystonia would benefit from such resources, especially given the developmental differences in neuroimaging data between adults and children. We assembled pediatric normative neuroimaging resources from open-access datasets in order to comply with age-related anatomical and functional differences in pediatric DBS populations. We illustrated their utility in a cohort of children with dystonia treated with pallidal DBS. We aimed to derive a local pallidal sweetspot and explore a connectivity fingerprint associated with pallidal stimulation to exemplify the utility of the assembled imaging resources. METHODS: An average pediatric brain template (the MNI brain template 4.5-18.5 years) was implemented and used to localize the DBS electrodes in 20 patients from the GEPESTIM registry cohort. A pediatric subcortical atlas, analogous to the DISTAL atlas known in DBS research, was also employed to highlight the anatomical structures of interest. A local pallidal sweetspot was modeled, and its degree of overlap with stimulation volumes was calculated as a correlate of individual clinical outcomes. Additionally, a pediatric functional connectome of 100 neurotypical subjects from the Consortium for Reliability and Reproducibility was built to allow network-based analyses and decipher a connectivity fingerprint responsible for the clinical improvements in our cohort. RESULTS: We successfully implemented a pediatric neuroimaging dataset that will be made available for public use as a tool for DBS analyses. Overlap of stimulation volumes with the identified DBS-sweetspot model correlated significantly with improvement on a local spatial level (R = 0.46, permuted p = 0.019). The functional connectivity fingerprint of DBS outcomes was determined to be a network correlate of therapeutic pallidal stimulation in children with dystonia (R = 0.30, permuted p = 0.003). CONCLUSIONS: Local sweetspot and distributed network models provide neuroanatomical substrates for DBS-associated clinical outcomes in dystonia using pediatric neuroimaging surrogate data. Implementation of this pediatric neuroimaging dataset might help to improve the practice and pave the road towards a personalized DBS-neuroimaging analyses in pediatric patients.

Intracavitary brachytherapy using stereotactically applied phosphorus-32 colloid for treatment of cystic craniopharyngiomas in 53 patients.

This paper summarizes outcomes of a single-center study of intracavitary brachytherapy (IBT) with stereotactically applied phosphorus-32 ((32)P) colloid for treatment of cystic craniopharyngiomas. We assessed its efficacy and safety, on the basis of clinical and radiological outcomes in one of the largest reported patient series. Between 1992 and 2011, 53 patients were treated with IBT, 14 without previous treatment and 39 who had previously been treated for recurrent cysts. Intervention was performed by applying 200 Gy to the internal cyst wall (median volume 6.1 ml). Median clinical and radiological follow-up were 60.2 and 53.0 months, respectively. Actuarial tumor cyst control was 86.0 ± 5.3 % at 12, 24, and 60 months. Actuarial out-of-field control (development of new cysts or progression of solid tumor parts) was 90.9 ± 4.3, 84.0 ± 5.6, and 54.5 ± 8.8 % after 12, 24, and 60 months, respectively. Corresponding actuarial overall progression-free survival was 79.4 ± 6.1, 72.4 ± 6.8, and 45.6 ± 8.7 % at 12, 24, and 60 months, respectively. Visual function improved for 12 patients (23.5 %), remained unchanged for 34 patients (66.7 %), and worsened for five patients (9.8 %), correlating with tumor progression in each case. Endocrinological deterioration occurred for ten patients (19.6 %); for nine patients this was a result of tumor progression or after tumor resection and for one it was attributed to irradiation. Within six months of IBT seven patients (13.7 %) experienced transient neurological deficits and two patients (3.9 %) deteriorated permanently (hemiparesis and third nerve palsy). Stereotactically applied (32)P is highly efficacious for control of cystic components of craniopharyngiomas and is associated with a low risk of permanent morbidity. The procedure does not, however affect the development of new cysts or the progression of solid tumor parts.

DiODe v2: Unambiguous and Fully-Automated Detection of Directional DBS Lead Orientation.

Directional deep brain stimulation (DBS) leads are now widely used, but the orientation of directional leads needs to be taken into account when relating DBS to neuroanatomy. Methods that can reliably and unambiguously determine the orientation of directional DBS leads are needed. In this study, we provide an enhanced algorithm that determines the orientation of directional DBS leads from postoperative CT scans. To resolve the ambiguity of symmetric CT artifacts, which in the past, limited the orientation detection to two possible solutions, we retrospectively evaluated four different methods in 150 Cartesia™ directional leads, for which the true solution was known from additional X-ray images. The method based on shifts of the center of mass (COM) of the directional marker compared to its expected geometric center correctly resolved the ambiguity in 100% of cases. In conclusion, the DiODe v2 algorithm provides an open-source, fully automated solution for determining the orientation of directional DBS leads.

PSA and VIM DBS efficiency in essential tremor depends on distance to the dentatorubrothalamic tract.

OBJECTIVE: To investigate the relation between deep brain stimulation (DBS) of the posterior-subthalamic-area (PSA) and the ventral-intermediate-nucleus (VIM) and the distance to the dentatorubrothalamic tract (DRTT) in essential tremor (ET). METHODS: Tremor rating scale (TRS) hemi-scores were analyzed in 13 ET patients, stimulated in both the VIM and the PSA in a randomized, crossover trial. Distances of PSA and VIM contacts to population-based DRTTs were calculated. The relationships between distance to DRTT and stimulation amplitude, as well as DBS efficiency (TRS improvement per amplitude) were investigated. RESULTS: PSA contacts were closer to the DRTT (p = 0.019) and led to a greater improvement in TRS hemi-scores (p = 0.005) than VIM contacts. Proximity to the DRTT was related to lower amplitudes (p < 0.001) and higher DBS efficiency (p = 0.017). CONCLUSIONS: Differences in tremor outcome and stimulation parameters between contacts in the PSA and the VIM can be explained by their different distance to the DRTT.

Thalamic Deep Brain Stimulation in Essential Tremor Plus Is as Effective as in Essential Tremor.

The new essential tremor (ET) classification defined ET-plus (ET-p) as an ET subgroup with additional neurological signs besides action tremor. While deep brain stimulation (DBS) is effective in ET, there are no studies specifically addressing DBS effects in ET-p. 44 patients with medication-refractory ET and thalamic/subthalamic DBS implanted at our center were postoperatively classified into ET and ET-p according to preoperative documentation. Tremor suppression with DBS (stimulation ON vs. preoperative baseline and vs. stimulation OFF), measured via the Fahn-Tolosa-Marin tremor rating scale (TRS), stimulation parameters, and the location of active contacts were compared between patients classified as ET and ET-p. TRS scores at baseline were higher in ET-p. ET-p patients showed comparable tremor reduction as patients with ET, albeit higher stimulation parameters were needed in ET-p. Active electrode contacts were located more dorsally in ET-p of uncertain reason. Our data show that DBS is similarly effective in ET-p compared to ET. TRS scores were higher in ET-p preoperatively, and higher stimulation parameters were needed for tremor reduction compared to ET. The latter may be related to a more dorsal location of active electrode contacts in the ET-p group of this cohort. Prospective studies are warranted to investigate DBS in ET-p further.