Anatomical Targets Research Articles

Preclinical Dosimetry for Small Animal Radiation Research in Proton Therapy: A Feasibility Study.

To evaluate the feasibility of the three-dimensional (3D) printed small animal phantoms in dosimetric verification of proton therapy for small animal radiation research. Two different phantoms were modeled using the computed-tomography dataset of real rat and tumor-bearing mouse, retrospectively. Rat phantoms were designed to accommodate both EBT3 film and ionization chamber. A subcutaneous tumor-bearing mouse phantom was only modified to accommodate film dosimetry. All phantoms were printed using polylactic-acid (PLA) filament. Optimal printing parameters were set to create tissue-equivalent material. Then, proton therapy plans for different anatomical targets, including whole brain and total lung irradiation in the rat phantom and the subcutaneous tumor model in the mouse phantom, were created using the pencil-beam scanning technique. Point dose and film dosimetry measurements were performed using 3D-printed phantoms. In addition, all phantoms were analyzed in terms of printing accuracy and uniformity. Three-dimensionally printed phantoms had excellent uniformity over the external body, and printing accuracy was within 0.5 mm. According to our findings, two-dimensional dosimetry with EBT3 showed acceptable levels of γ passing rate for all measurements except for whole brain irradiation (γ passing rate, 89.8%). In terms of point dose analysis, a good agreement (<0.1%) was found between the measured and calculated point doses for all anatomical targets. Three-dimensionally printed small animal phantoms show great potential for dosimetric verifications of clinical proton therapy for small animal radiation research.

Drilling accuracy evaluation of a mouldable surgical targeting system for minimally invasive access to anatomic targets in the temporal bone.

Minimally invasive cochlear implant surgery using a micro-stereotactic surgical targeting system with on-site moulding of the template aims for a reliable, less experience-dependent access to the inner ear under maximal reduction of trauma to anatomic structures. We present an accuracy evaluation of our system in ex-vivo testing. Eleven drilling experiments were performed on four cadaveric temporal bone specimens. The process involved preoperative imaging after affixing the reference frame to the skull, planning of a safe trajectory preserving relevant anatomical structures, customization of the surgical template, execution of the guided drilling and postoperative imaging for determination of the drilling accuracy. Deviation between the drilled and desired trajectories was measured at different depths. All drilling experiments were successfully performed. Other than purposely sacrificing the chorda tympani in one experiment, no other relevant anatomy, such as facial nerve, chorda tympani, ossicles or external auditory canal were harmed. Deviation between the desired and achieved path was found to be 0.25 ± 0.16mm at skulls' surface and 0.51 ± 0.35mm at the target level. The closest distance of the drilled trajectories' outer circumference to the facial nerve was 0.44mm. We demonstrated the usability for drilling to the middle ear on human cadaveric specimen in a pre-clinical setting. Accuracy proved to be suitable for many applications such as procedures within the field of image-guided neurosurgery. Promising approaches to reach sufficient submillimetre accuracy for CI surgery have been outlined.

SynBOLD-DisCo: Synthetic BOLD images for distortion correction of fMRI without additional calibration scans.

The blood oxygen level dependent (BOLD) signal from functional magnetic resonance imaging (fMRI) is a noninvasive technique that has been widely used in research to study brain function. However, fMRI suffers from susceptibility-induced off resonance fields which may cause geometric distortions and mismatches with anatomical images. State-of-the-art correction methods require acquiring reverse phase encoded images or additional field maps to enable distortion correction. However, not all imaging protocols include these additional scans and thus cannot take advantage of these susceptibility correction capabilities. As such, in this study we aim to enable state-of-the-art distortion correction with FSL's topup algorithm of historical and/or limited fMRI data that include only a structural image and single phase encoded fMRI. To do this, we use 3D U-net models to synthesize undistorted fMRI BOLD contrast images from the structural image and use this undistorted synthetic image as an anatomical target for distortion correction with topup. We evaluate the efficacy of this approach, named SynBOLD-DisCo (synthetic BOLD images for distortion correction), and show that BOLD images corrected using our approach are geometrically more similar to structural images than the distorted BOLD data and are practically equivalent to state-of-the-art correction methods which require reverse phase encoded data. Future directions include additional validation studies, integration with other preprocessing operations, retraining with broader pathologies, and investigating the effects of spin echo versus gradient echo images for training and distortion correction. In summary, we demonstrate SynBOLD-DisCo corrects distortion of fMRI when reverse phase encoding scans or field maps are not available.

Effect of Deep Brain Stimulation in The Ventral Tegmental Area on Neuronal Activity in Local and Remote Brain Regions in Kindled Mice.

The mechanisms behind seizure suppression by deep brain stimulation (DBS) are not fully revealed, and the most optimal stimulus regimens and anatomical targets are yet to be determined. We investigated the modulatory effect of low-frequency DBS (L-DBS) in the ventral tegmental area (VTA) on neuronal activity in downstream and upstream brain areas in chemically kindled mice by assessing c-Fos immunoreactivity. In this experimental study, 4-6 weeks old BL/6 male mice underwent stereotaxic implantation of a unilateral stimulating electrode in the VTA followed by pentylenetetrazole (PTZ) administration every other day until they showed stage 4 or 5 seizures following 3 consecutive PTZ injections. Animals were divided into control, sham-implanted, kindled, kindled-implanted, L-DBS, and kindled+L-DBS groups. In the L-DBS and kindled+L-DBS groups, four trains of L-DBS were delivered 5 min after the last PTZ injection. 48 hours after the last L-DBS, mice were transcardially perfused, and the brain was processed to evaluate c-Fos expression by immunohistochemistry. L-DBS in the VTA significantly decreased the c-Fos expressing cell numbers in several brain areas including the hippocampus, entorhinal cortex, VTA, substantia nigra pars compacta, and dorsal raphe nucleus but not in the amygdala and CA3 area of the ventral hippocampus compared to the sham group. These data suggest that the possible anticonvulsant mechanism of DBS in VTA can be through restoring the seizure-induced cellular hyperactivity to normal.

129 Anatomical Approaches to Treating Obstructive Sleep Apnea in Patients who Fail CPAP: State of the Art Review

OBJECTIVES/GOALS: The aim of this study was to evaluate current and new anatomical approaches to treating obstructive sleep apnea (OSA) in patients who fail continuous positive airway pressure (CPAP). Understanding the breadth of devices and procedures increases clinical scope of practice and innovator opportunities. METHODS/STUDY POPULATION: A comprehensive review of literature, FDA approvals, patents, and commercially available technologies was undertaken with regards to anatomical approaches for treating OSA. These include experimental therapies, surgical approaches, and non-surgical ablative procedures. Oral appliances, positive airway pressure devices, and therapeutics were excluded. Key search terms included obstructive sleep apnea,’ anatomy,’ surgery,’ devices,’ experimental therapy,’ innovation,’ technology,’ and translational research.’ Publications were limited to the last five years. Innovations were evaluated for relevance to OSA treatment and then assessed in greater depth based on scientific literature. RESULTS/ANTICIPATED RESULTS: Numbers of preclinical and commercially available innovations pertinent to the anatomical treatment of OSA were reported along with clinically relevant outcome metrics. The greatest number of innovations was found in surgical approaches, including soft-tissue removal, orthognathic surgery, and electrical stimulation. Outcome parameters included safety, efficacy, patient compliance, and mean disease alleviation as a ratio of efficacy to compliance. Innovations were grouped by their intended anatomical targets including retrolingual, palatal, oropharyngeal, epiglottic, nasal, and complete concentric collapse, making special note of gaps in the treatment armamentarium. DISCUSSION/SIGNIFICANCE: In the last decade, sleep surgery has trended toward innovative CPAP alternatives. Nerve stimulation and ablative procedures have grown, but some anatomical presentations have been frequently excluded. These developments present opportunities for innovators to fill persistent gaps in treatment.

The Fifth Bioelectronic Medicine Summit Hosted by the Feinstein Institutes for Medical Research (Manhasset, NY) and Columbia Engineering (NY, NY) at The Garden City Hotel, Garden City, NY 11530 on October 11-12th, 2022- Bioelectronic Medicine: Today’s Tools, Tomorrow’s Therapies

The Fifth Bioelectronic Medicine Summit Hosted by the Feinstein Institutes for Medical Research (Manhasset, NY) and Columbia Engineering (NY, NY) at The Garden City Hotel, Garden City, NY 11530 on October 11-12th, 2022- Bioelectronic Medicine: Today’s Tools, Tomorrow’s Therapies

Abstract Number ‐ 13: Endovascular BCI to Restore Motor Control for the Command of Digital Devices in Severe Quadriparesis

Introduction Brain‐computer interfaces (BCIs), functioning as motor neuroprostheses, have the potential to restore the transmission of neural signal from the cerebral cortex to control digital devices and improve functional independence in patients with severe paralysis due to brain, spinal cord, peripheral nerve or muscle dysfunction. Methods COMMAND is an FDA‐approved, NIH‐funded single arm, open‐label, prospective early feasibility study designed to enroll 6 patients with severe quadriparesis to receive an endovascular implantable motor neuroprosthesis (Stentrode, Synchron Inc, Brooklyn, NY). The primary outcome measures include treatment related serious adverse events within 12‐month after device implantation. Secondary outcome measures include restoration of neural signal from the cerebral cortex utilized for neuromuscular control of digital devices, resulting in the successful execution of non‐mechanical digital commands, e.g., for the control of personal computers. The study device comprises of three parts: 1) Endovascular electrode array and lead (StentrodeTM), implanted percutaneously via the jugular vein in the superior sagittal sinus adjacent to the motor cortex using endovascular approach; 2) Implantable Receiver Transmitter Unit (IRTU) implanted in the pectoral region; and 3) Controller, including an External Receiver Transmitter Unit (ERTU), Signal Control Unit (SCU) and Software Application. Results A 67 year‐old patient with complete quadriplegia from amyotrophic lateral sclerosis (ALS) enrolled into the study and completed a screening process, which included CTV and MRV to ascertain normal venous sinus anatomy, with two patent jugular veins and bilateral patent transverse sinuses. Using a right internal jugular vein access, the investigational endovascular Stentrode BCI was implanted in the superior sagittal sinus adjacent to primary motor cortex. Co‐registration to enable accurate anatomical targeting was achieved by fusing structural MRI data with intra‐procedurally acquired 3D‐volume (3D‐DSA). A sub‐clavicular subcutaneous pocket was created to place the IRTU. Then, the lead was tunneled to the pocket and connected to the IRTU. Before closure of the wound, impedance measurement was taken which confirmed functionality of the system. The patient tolerated the procedure very well, was successfully extubated after the procedure and remained neurologically at his baseline. The patient was started on dual antiplatelet therapy 2 weeks prior to the surgery and will be continued on this regimen for 3 months.The participant will undergo machine‐learning‐assisted training to use wirelessly transmitted electrocorticography signals associated with attempted movements to control multiple mouse‐click actions, including zoom and left‐click. Used in combination with an eye‐tracker for cursor navigation, the patient will practice controlling a computer to conduct instrumental activities of daily living (IADL) tasks. Conclusions We describe the first US in‐human experience of a minimally invasive, fully implanted, wireless motor neuroprosthesis using an endovascular stent‐electrode array to transmit electrocorticography signals from the motor cortex for multiple command control of digital devices.

Improving the metric of surgical freedom in the laboratory based on a novel concept of volume.

In laboratory-based neuroanatomical studies, surgical freedom, the most important metric of instrument maneuverability, has been based on Heron's formula. Inaccuracies and limitations hinder this study design's applicability. A new methodology, volume of surgical freedom (VSF), may produce a more realistic qualitative and quantitative representation of a surgical corridor. Overall, 297 data set measurements assessing surgical freedom were completed for cadaveric brain neurosurgical approach dissections. Heron's formula and VSF were calculated specifically to different surgical anatomical targets. Quantitative accuracy and the results of an analysis of human error were compared. Heron's formula for irregularly shaped surgical corridors resulted in overestimation of the respective areas (minimum overestimation 31.3%). In 92% (188/204) of data sets reviewed for influence of offset, areas calculated on the basis of measured data points were larger than areas calculated on the basis of the translated best-fit plane points (mean [SD] overestimation of 2.14% [2.62%]). Variability in the probe length attributable to human error was small (mean [SD] calculated probe length 190.26 mm [5.57 mm]). VSF is an innovative concept that can develop a model of a surgical corridor producing better assessment and prediction of the ability to maneuver and manipulate surgical instruments. VSF corrects for deficits in Heron's method by generating the correct area for an irregular shape using the shoelace formula, adjusting the data points to account for offset, and attempting to correct for human error. VSF produces 3-dimensional models and, therefore, is a preferable standard for assessing surgical freedom.

Analysis of Cephalometric Points in Male and Female Mandibles: An Application to Gender-Affirming Facial Surgery.

Gender-affirming facial surgery is a common intervention for transgender patients because of its ability to decrease the frequency of misgendering. Many anatomic targets can be addressed, but the mandible is the primary aspect of the lower third of the face that is manipulated during these procedures. This study's objective is to quantify the differences in cephalometric measurements between male and female mandibles on maxillofacial imaging, with the goal of identifying surgical targets for gender affirmation. A nonrandomized, retrospective, single-institution, case-control study of 387 patients who underwent maxillofacial computed tomography during 2017-2020 was performed. After excluding patients with imaging that did not capture the entire head or had deforming pathology of the face, a total of 113 patients were included. Cephalometric measurements that corresponded to areas reported by patients as sources of dysphoria were selected for analysis. These included mandibular width, ramus height, lateral flare, masseter volume, total face height, and the values of the mandibular angles in degrees. The relationship of masseter volume to the other measurements was also characterized. Significantly greater masseter volume was seen in males compared with females, and a greater masseter thickness was also seen in males. The mandibular angle was more acute in males than females. Aggregate analysis of muscle volume and thickness was positively correlated with ramus height, lateral flare, and mandibular width. Ramus, mental, and total facial height correlated directly with patient height in males but not in females. These data provide a normative baseline for planning lower facial gender-affirming surgery.

Endoscopic Endonasal Accessibility and Maneuverability Around the Internal Carotid Artery from Distal Dural Ring to Foramen Lacerum: Cadaveric Study

Background: Expanded-endoscopic endonasal approaches (eEEA) to surgical targets around the internal carotid artery (ICA) remain inspiring and necessitate a special learning curve. Methods: Six formalin-fixed heads were dissected to study the 360° accessibility and manoeuvrability around ICAs from the distal dural ring (DDR) to the foramen lacerum (FL) on each side (n=12) via eEEA. The ICA course was divided into three segments: ICA in cavernous sinus (CS-ICA), paraclival-ICA and lacerum-ICA. Following total exposure of each ICA, the three-dimensional (3D= medial/lateral, superficial/deep and above/below) anatomical targets (n= 35) around each ICA were evaluated. The data were collected and analyzed. Results: Distinctively, we included 35 anatomical targets (pertinent to CS-ICA, paraclival-ICA and lacerum-ICA were 16, 10, and 9, respectively) in 360° around every ICA (n=12) from the DDR to FL. Although reasonable visual validation was possible for all targets, micro-dissections were safely achievable for 19 targets (54.3%) through full or limited surgical freedom in 73.7% and 26.3%, respectively. In the remaining 45.7%, the accessibility to targets was abandoned due to hazardous manipulation. The most unreachable targets were around the lacerum-ICA (55.6%) with extremely restricted maneuverability (75%). Though, favorable accessibility (60%) and full surgical freedom (100%) were around the paraclival-ICA. Conclusion: This study delivers a distinctive view to appreciate the degree of complexity and invasiveness in relation to the degree of surgical freedom around ICA via eEEA. Illustrating these details for skull base surgeons can lead them to tailor their approach. It delivers prospective feedback for our operative theatre.

HAPPY: Hip Arthroscopy Portal Placement Using Augmented Reality.

Correct positioning of the endoscope is crucial for successful hip arthroscopy. Only with adequate alignment can the anatomical target area be visualized and the procedure be successfully performed. Conventionally, surgeons rely on anatomical landmarks such as bone structure, and on intraoperative X-ray imaging, to correctly place the surgical trocar and insert the endoscope to gain access to the surgical site. One factor complicating the placement is deformable soft tissue, as it can obscure important anatomical landmarks. In addition, the commonly used endoscopes with an angled camera complicate hand-eye coordination and, thus, navigation to the target area. Adjusting for an incorrectly positioned endoscope prolongs surgery time, requires a further incision and increases the radiation exposure as well as the risk of infection. In this work, we propose an augmented reality system to support endoscope placement during arthroscopy. Our method comprises the augmentation of a tracked endoscope with a virtual augmented frustum to indicate the reachable working volume. This is further combined with an in situ visualization of the patient anatomy to improve perception of the target area. For this purpose, we highlight the anatomy that is visible in the endoscopic camera frustum and use an automatic colorization method to improve spatial perception. Our system was implemented and visualized on a head-mounted display. The results of our user study indicate the benefit of the proposed system compared to baseline positioning without additional support, such as an increased alignment speed, improved positioning error and reduced mental effort. The proposed approach might aid in the positioning of an angled endoscope, and may result in better access to the surgical area, reduced surgery time, less patient trauma, and less X-ray exposure during surgery.

Cranial Electrotherapy Stimulation (CES) for Major Depressive Disorder

Cranial electrotherapy stimulation (CES) is a noninvasive neuromodulation technique that has potential for treating several psychiatric diseases. This method consists of delivering bilateral low-intensity electrical current, via a pair of electrodes, to different anatomical targets around the head. This kind of stimulation is believed to interact with brain oscillation patterns, resulting in changes in connectivity of brain networks. CES has been observed to be a safe intervention with no serious side effects reported in randomized controlled trials. Unequivocal efficiency of CES has not been demonstrated for the treatment of major depressive disorder (MDD); however, some data suggest that CES could be an effective therapy for MDD, either as a standalone or in combination with pharmacological treatment and psychological therapy. CES devices are portable devices that do not required trained personnel to administer the treatment and therefore allow the patients to self-administer the treatment at home. [ Psychiatr Ann . 2022;52(11):461–465.]

Semantic Graph Attention With Explicit Anatomical Association Modeling for Tooth Segmentation From CBCT Images.

Accurate tooth identification and delineation in dental CBCT images are essential in clinical oral diagnosis and treatment. Teeth are positioned in the alveolar bone in a particular order, featuring similar appearances across adjacent and bilaterally symmetric teeth. However, existing tooth segmentation methods ignored such specific anatomical topology, which hampers the segmentation accuracy. Here we propose a semantic graph-based method to explicitly model the spatial associations between different anatomical targets (i.e., teeth) for their precise delineation in a coarse-to-fine fashion. First, to efficiently control the bilaterally symmetric confusion in segmentation, we employ a lightweight network to roughly separate teeth as four quadrants. Then, designing a semantic graph attention mechanism to explicitly model the anatomical topology of the teeth in each quadrant, based on which voxel-wise discriminative feature embeddings are learned for the accurate delineation of teeth boundaries. Extensive experiments on a clinical dental CBCT dataset demonstrate the superior performance of the proposed method compared with other state-of-the-art approaches.

Evaluating Multidisciplinary Peer Review: A Retrospective Study of Plan Modifications in Radical and Palliative Intent Radiation Therapy Treatments

<h3>Purpose/Objective(s)</h3> Multidisciplinary peer review of radiation therapy treatment plans is recognized as an integral component to improving quality and safety. Our institution has established a goal of 100% peer review completion for all radiation therapy treatment plans, of both radical and palliative intent. This study investigates whether treatment intent influences the rate of plan modifications (PM) arising from peer review recommendations, and whether the timing of when peer review is conducted may modulate any effect. <h3>Materials/Methods</h3> Peer review primarily focused on target volume, dose, and fractionation. Pertinent clinical and treatment plan characteristics were extracted, including intent (radical/palliative), whether the treatment plan followed institutional protocol or not, and anatomical target site. The primary endpoint was PM rate, defined as any change implemented following recommendations from peer review. All treatment plans peer reviewed between November 2015 – November 2016 (cohort 1) and November 2016 – November 2017 (cohort 2) were analyzed. Between the 1^st and 2^nd cohort, a new institutional policy was introduced requiring peer review to occur prior to commencement of treatment planning. To evaluate the effect, we developed a causal model involving intent as the exposure variable, PM as the outcome variable, and both target site and protocol treatment, as confounding variables. Logistic regression analysis was used to describe the relationship between the variables influencing the PM decision process. <h3>Results</h3> A total of 3807 radiation therapy treatment plans involving 2608 patients were included in the analysis. Among the initial cohort (1740 treatments, 1195 patients), plans with palliative intent were 35% less likely to have a PM (OR = 0.65, CI = 0.49 - 0.86) compared to those with radical intent. However, following the policy change, in the second cohort (2067 treatments, 1413 patients), the probability of PM for plans with either palliative or radical intent was equally likely (OR = 1, CI = 0.76 – 1.31). <h3>Conclusion</h3> We found that treatment plans of palliative intent were initially 35% less likely to be modified than those of radical intent, however, this difference was nullified by the change in timing of when peer review occurred in the treatment planning process. This may be explained by possible biases against PM in palliative treatments where the perceived clinical impact may not be felt to outweigh the additional work required. Earlier integration of peer review within the treatment planning process may contribute to reducing potential intent bias in decision making regarding peer review recommendations.

Verification of multi-structure targeting in chronic microelectrode brain recordings from CT scans

BackgroundLarge-scale microelectrode recordings offer a unique opportunity to study neurophysiological processes at the network level with single cell resolution. However, in the small brains of many experimental animals, it is often technically challenging to verify the correct targeting of the intended structures, which inherently limits the reproducibility of acquired data. New methodTo mitigate this problem, we have developed a method to programmatically segment the trajectory of electrodes arranged in larger arrays from acquired CT-images and thereby determine the position of individual recording tips with high spatial resolution, while also allowing for coregistration with an anatomical atlas, without pre-processing of the animal samples or post-imaging histological analyses. ResultsTesting the technical limitations of the developed method, we found that the choice of scanning angle influences the achievable spatial resolution due to shadowing effects caused by the electrodes. However, under optimal acquisition conditions, individual electrode tip locations within arrays with 250 µm inter-electrode spacing were possible to reliably determine. Comparison to existing methodsComparison to a histological verification method suggested that, under conditions where individual wires are possible to track in slices, a 90% correspondence could be achieved in terms of the number of electrodes groups that could be reliably assigned to the same anatomical structure. ConclusionsThe herein reported semi-automated procedure to verify anatomical targeting of brain structures in the rodent brain could help increasing the quality and reproducibility of acquired neurophysiological data by reducing the risk of assigning recorded brain activity to incorrectly identified anatomical locations. Data availabilityThe tools developed in this study are freely available as a software package at: https://github.com/NRC-Lund/ct-tools

O068 / #830 DORSAL ROOT GANGLION STIMULATION AS A SALVAGE THERAPY FOLLOWING FAILED SPINAL CORD STIMULATION: TRACK 1: SPINAL CORD STIMULATION, BEST PRACTICES, AND STUDIES

Spinal cord stimulation (SCS) can provide long-term pain relief for various chronic pain conditions, but some patients have no relief with trial stimulation or lose efficacy over time. To ‘salvage’ relief in patients who do not respond or have lost efficacy, alternative stimulation paradigms or anatomical targets can be considered. Dorsal root ganglion stimulation (DRG-S) has a different mechanism of action and anatomical target than SCS. Objective: We assessed DRG-S salvage therapy outcomes in patients who did not respond to SCS or had lost SCS efficacy.

Deep brain stimulation for movement disorders after stroke: a systematic review of the literature.

Stroke remains the leading cause of disability in the United States. Even as acute care for strokes advances, there are limited options for improving function once the patient reaches the subacute and chronic stages. Identification of new therapeutic approaches is critical. Deep brain stimulation (DBS) holds promise for these patients. A number of case reports and small case series have reported improvement in movement disorders after strokes in patients treated with DBS. In this systematic review, the authors have summarized the patient characteristics, anatomical targets, stimulation parameters, and outcomes of patients who have undergone DBS treatment for poststroke movement disorders. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. The PubMed, Scopus, and SpringerLink databases were searched for the keywords "DBS," "stroke," "movement," and "recovery" to identify patients treated with DBS for movement disorders after a stroke. The Joanna Briggs Institute Critical Appraisal checklists for case reports and case series were used to systematically analyze the quality of the included studies. Data collected from each study included patient demographic characteristics, stroke diagnosis, movement disorder, DBS target, stimulation parameters, complications, and outcomes. The authors included 29 studies that described 53 patients who underwent placement of 82 total electrodes. Movement disorders included tremor (n = 18), dystonia (n = 18), hemiballism (n = 6), spastic hemiparesis (n = 1), chorea (n = 1), and mixed disorders (n = 9). The most common DBS targets were the globus pallidus internus (n = 32), ventral intermediate nucleus of thalamus (n = 25), and subthalamic area/subthalamic nucleus (n = 7). Monopolar stimulation was reported in 43 leads and bipolar stimulation in 13. High-frequency stimulation was used in 57 leads and low-frequency stimulation in 6. All patients but 1 had improvement in their movement disorders. Two complications were reported: speech impairment in 1 patient and hardware infection in another. The median (interquartile range) duration between stroke and DBS treatment was 6.5 (2.1-15.8) years. This is the first systematic review of DBS for poststroke movement disorders. Overall, most studies to date have been case reports and small series reporting heterogeneous patients and surgical strategies. This review suggests that DBS for movement disorders after a stroke has the potential to be effective and safe for diverse patients, and DBS may be a feasible option to improve function even years after a stroke.

Responsive neurostimulation in pediatric patients with drug-resistant epilepsy.

Medically refractory epilepsy remains a therapeutic challenge when resective surgery is not a practical option and indirect neurostimulation efficacy may be limited. In these instances responsive neurostimulation (RNS) has been used in adults, with good outcomes in most patients. However, the utility of RNS in children and young adults has not been systematically explored. In this study, the authors present a single institution's experience with RNS in pediatric patients. A single-center retrospective chart review of patients who underwent RNS implantation at Phoenix Children's Hospital during the 4-year period between January 2018 and December 2021 was performed. Following evaluation for epilepsy surgery, 22 patients underwent RNS implantation using different anatomical targets depending on the predetermined epileptic focus/network. In the cohort, 59% of patients were male, the mean age at implantation was 16.4 years (range 6-22 years), and the mean follow-up time was 2.7 years (range 1.0-4.3 years). All patients had a preoperative noninvasive evaluation that included MRI, video-electroencephalography, and resting-state functional MRI. Additionally, 13 patients underwent invasive monitoring with stereo-electroencephalography to help determine RNS targets. All patients had variable positive responses with reduction of seizure frequency and/or intensity. Overall, seizure frequency reduction of > 50% was seen in the majority (86%) of patients. There were two complications: one patient experienced transitory weakness and one generator failed, requiring replacement. A patient died of sudden unexpected death in epilepsy 3 years after implantation despite being seizure free during the previous year. RNS used in children with medically refractory epilepsy improved seizure control after implantation, with decreases in seizure frequency > 50% from preoperative baseline in the majority of patients. Preliminary findings indicate that functional MRI and stereo-electroencephalography were helpful for RNS targeting and that RNS can be used safely even in young children.

Accuracy, precision, and safety of stereotactic, frame-based, intraoperative MRI-guided and MRI-verified deep brain stimulation in 650 consecutive procedures.

Suboptimal lead placement is one of the most common indications for deep brain stimulation (DBS) revision procedures. Confirming lead placement in relation to the visible anatomical target with dedicated stereotactic imaging before terminating the procedure can mitigate this risk. In this study, the authors examined the accuracy, precision, and safety of intraoperative MRI (iMRI) to both guide and verify lead placement during frame-based stereotactic surgery. A retrospective analysis of 650 consecutive DBS procedures for targeting accuracy, precision, and perioperative complications was performed. Frame-based lead placement took place in an operating room equipped with an MRI machine using stereotactic images to verify lead placement before removing the stereotactic frame. Immediate lead relocation was performed when necessary. Systematic analysis of the targeting error was calculated. Verification of 1201 DBS leads with stereotactic MRI was performed in 643 procedures and with stereotactic CT in 7. The mean ± SD of the final targeting error was 0.9 ± 0.3 mm (range 0.1-2.3 mm). Anatomically acceptable lead placement was achieved with a single brain pass for 97% (n = 1164) of leads; immediate intraoperative relocation was performed in 37 leads (3%) to obtain satisfactory anatomical placement. General anesthesia was used in 91% (n = 593) of the procedures. Hemorrhage was noted after 4 procedures (0.6%); 3 patients (0.4% of procedures) presented with transient neurological symptoms, and 1 experienced delayed cognitive decline. Two bleeds coincided with immediate relocation (2 of 37 leads, 5.4%), which contrasts with hemorrhage in 2 (0.2%) of 1164 leads implanted on the first pass (p = 0.0058). Three patients had transient seizures in the postoperative period. The seizures coincided with hemorrhage in 2 of these patients and with immediate lead relocation in the other. There were 21 infections (3.2% of procedures, 1.5% in 3 months) leading to hardware removal. Delayed (> 3 months) retargeting of 6 leads (0.5%) in 4 patients (0.6% of procedures) was performed because of suboptimal stimulation benefit. There were no MRI-related complications, no permanent motor deficits, and no deaths. To the authors' knowledge, this is the largest series reporting the use of iMRI to guide and verify lead location during DBS surgery. It demonstrates a high level of accuracy, precision, and safety. Significantly higher hemorrhage was encountered when multiple brain passes were required for lead implantation, although none led to permanent deficit. Meticulous audit and calibration can improve precision and maximize safety.

Percutaneous Radiofrequency Sympatholysis in the Treatment of Primary Palmar Hyperhidrosis: A Retrospective Case-Controlled Study of Rib-Based Anatomical Targeting

PurposeTo compare the efficacy, adverse reactions, quality of life, and patient satisfaction of percutaneous radiofrequency (RF) thoracic sympatholysis at different rib-based anatomic targets for primary palmar hyperhidrosis (PPHH). Materials and MethodsPatients with PPHH were divided according to the target, namely, the upper edge (Group U) and lateral border (Group L) of the fourth rib; there were 30 patients (mean age, 24.9 years; women, 31, 51.7%) and 60 cases in each group. The Hyperhidrosis Disease Severity Scale (HDSS) and Dermatology Life Quality Index (DLQI) were assessed. ResultsFrom before RF sympatholysis to 12 months after, the proportion of patients with HDSS Grades III and IV (100%–26.7%) and the DLQI (19.78 ± 5.08 to 4.98 ± 4.18) decreased significantly (P < .001). At 3, 6, and 12 months after RF, the HDSS grades were better in Group L than in Group U (P = .005, .002, and .004). At 6 and 12 months after RF, the DLQI in Group L was lower than that in Group U (P = .012 and .016), and at 1, 6, and 12 months after RF, patient satisfaction was higher than that in Group U (P = .025, .014, and .009). Adverse events were mild; 8 patients (13.3%) demonstrated compensatory hyperhidrosis at 12 months after RF, and there was no difference between the 2 groups (P = .448); neuralgia and pneumothorax also did not differ (P = .522 and .643). ConclusionsRF sympatholysis targeting the lateral border of the fourth rib had higher efficacy, better quality of life, and higher patient satisfaction.