Vivek P. Buch, MD

All Publications

• Ictal Involvement of the Pulvinar and the Anterior Nucleus of the Thalamus in Patients With Refractory Epilepsy. Neurology McGinn, R., Von Stein, E. L., Datta, A., Wu, T., Lusk, Z., Nam, S., Dilts-Garcha, M., Fisher, R. S., Buch, V., Parvizi, J. 2024; 103 (11): e210039

  Abstract

  Deep brain stimulation (DBS) targeting the anterior nucleus of the thalamus (ANT) has been shown to be effective in treating some patients with medically refractory epilepsy. However, it remains unknown how seizures spread through the ANT relative to other thalamic nuclei. This study aimed to investigate, through simultaneous recordings from both ANT and pulvinar (PLV) nucleus, their roles in seizure propagation. Our goal was to determine whether the ANT is the primary site of seizure propagation in the human thalamus, especially for focal seizure originating in the medial temporal lobe.In a retrospective design, we studied EEGs and clinical notes of patients with refractory epilepsy who were implanted with stereo-EEG (sEEG) electrodes across cortical regions, some of which were extended to reach various sites of the thalamus (i.e., multisite thalamic recordings). We selected patients from the Stanford Comprehensive Epilepsy Center with both ANT and PLV electrodes and collected information about the timing and anatomy of seizure activity in the seizure onset zones, usually temporal, and the 2 thalamic sites.We recruited 17 (5 female, mean age 32 years) adult patients with simultaneous ipsilateral ANT and PLV recordings. In all patients, the procedure was safe without any complications. In 100% of patients, the thalamus was involved during seizures (in 88% both ANT and PLV and in 82% first the PLV). In patients with confirmed hippocampal or amygdalar onset seizures, 62% had initial involvement and 100% had subsequent involvement of the PLV nucleus. Only 31% showed initial propagation to ANT. All focal-to-bilateral tonic-clonic seizures and most of the focal impaired awareness seizures had early involvement of both ANT and PLV, with rapid spread to the contralateral nuclei.sEEG of thalamic nuclei simultaneously provides an opportunity to understand propagation patterns of seizures with respect to each thalamic subdivision at the individual level. The patterns of seizure propagation, as we report here, provide insights about the prominent involvement of the PLV nucleus during seizure propagation. This may motivate future prospective work in larger cohorts of patients to understand how thalamic propagation may predict response to resective/ablative surgery or whether personalization of DBS (for instance, PLV instead of, or together with, ANT) could improve clinical outcomes.

  View details for DOI 10.1212/WNL.0000000000210039

  View details for PubMedID 39531602

• Cross-regional coordination of activity in the human brain during autobiographical self-referential processing. Proceedings of the National Academy of Sciences of the United States of America Stieger, J. R., Pinheiro-Chagas, P., Fang, Y., Li, J., Lusk, Z., Perry, C. M., Girn, M., Contreras, D., Chen, Q., Huguenard, J. R., Spreng, R. N., Edlow, B. L., Wagner, A. D., Buch, V., Parvizi, J. 2024; 121 (32): e2316021121

  Abstract

  For the human brain to operate, populations of neurons across anatomical structures must coordinate their activity within milliseconds. To date, our understanding of such interactions has remained limited. We recorded directly from the hippocampus (HPC), posteromedial cortex (PMC), ventromedial/orbital prefrontal cortex (OFC), and the anterior nuclei of the thalamus (ANT) during two experiments of autobiographical memory processing that are known from decades of neuroimaging work to coactivate these regions. In 31 patients implanted with intracranial electrodes, we found that the presentation of memory retrieval cues elicited a significant increase of low frequency (LF < 6 Hz) activity followed by cross-regional phase coherence of this LF activity before select populations of neurons within each of the four regions increased high-frequency (HF > 70 Hz) activity. The power of HF activity was modulated by memory content, and its onset followed a specific temporal order of ANTHPC/PMCOFC. Further, we probed cross-regional causal effective interactions with repeated electrical pulses and found that HPC stimulations cause the greatest increase in LF-phase coherence across all regions, whereas the stimulation of any region caused the greatest LF-phase coherence between that particular region and ANT. These observations support the role of the ANT in gating, and the HPC in synchronizing, the activity of cortical midline structures when humans retrieve self-relevant memories of their past. Our findings offer a fresh perspective, with high temporal fidelity, about the dynamic signaling and underlying causal connections among distant regions when the brain is actively involved in retrieving self-referential memories from the past.

  View details for DOI 10.1073/pnas.2316021121

  View details for PubMedID 39078679

• Safety and Efficacy of Staged, Bilateral Focused Ultrasound Thalamotomy in Essential Tremor: An Open-Label Clinical Trial. JAMA neurology Kaplitt, M. G., Krishna, V., Eisenberg, H. M., Elias, W. J., Ghanouni, P., Baltuch, G. H., Rezai, A., Halpern, C. H., Dalm, B., Fishman, P. S., Buch, V. P., Moosa, S., Sarva, H., Murray, A. M. 2024

  Abstract

  Unilateral magnetic resonance-guided focused ultrasound ablation of ventralis intermedius nucleus of the thalamus for essential tremor reduces tremor on 1 side, but untreated contralateral or midline symptoms remain limiting for some patients. Historically, bilateral lesioning produced unacceptable risks and was supplanted by deep brain stimulation; increasing acceptance of unilateral focused ultrasound lesioning has led to interest in a bilateral option.To evaluate the safety and efficacy of staged, bilateral focused ultrasound thalamotomy.This prospective, open-label, multicenter trial treated patients with essential tremor from July 2020 to October 2021, with a 12-month follow-up, at 7 US academic medical centers. Of 62 enrolled patients who had undergone unilateral focused ultrasound thalamotomy at least 9 months prior to enrollment, 11 were excluded and 51 were treated. Eligibility criteria included patient age (22 years and older), medication refractory, tremor severity (Clinical Rating Scale for Tremor [CRST] part A score ≥2 for postural or kinetic tremor), and functional disability (CRST part C score ≥2 in any category).A focused ultrasound system interfaced with magnetic resonance imaging allowed real-time alignment of thermography maps with anatomy. Subthreshold sonications allowed target interrogation for efficacy and off-target effects before creating an ablation.Tremor/motor score (CRST parts A and B) at 3 months for the treated side after treatment was the primary outcome measure, and secondary assessments for efficacy and safety continued to 12 months.The mean (SD) population age was 73 (13.9) years, and 44 participants (86.3%) were male. The mean (SD) tremor/motor score improved from 17.4 (5.4; 95% CI, 15.9-18.9) to 6.4 (5.3; 95% CI, 4.9 to 7.9) at 3 months (66% improvement in CRST parts A and B scores; 95% CI, 59.8-72.2; P < .001). There was significant improvement in mean (SD) postural tremor (from 2.5 [0.8]; 95% CI, 2.3 to 2.7 to 0.6 [0.9]; 95% CI, 0.3 to 0.8; P < .001) and mean (SD) disability score (from 10.3 [4.7]; 95% CI, 9.0-11.6 to 2.2 [2.8]; 95% CI, 1.4-2.9; P < .001). Twelve participants developed mild (study-defined) ataxia, which persisted in 6 participants at 12 months. Adverse events (159 of 188 [85%] mild, 25 of 188 [13%] moderate, and 1 severe urinary tract infection) reported most commonly included numbness/tingling (n = 17 total; n = 8 at 12 months), dysarthria (n = 15 total; n = 7 at 12 months), ataxia (n = 12 total; n = 6 at 12 months), unsteadiness/imbalance (n = 10 total; n = 0 at 12 months), and taste disturbance (n = 7 total; n = 3 at 12 months). Speech difficulty, including phonation, articulation, and dysphagia, were generally mild (rated as not clinically significant, no participants with worsening in all 3 measures) and transient.Staged, bilateral focused ultrasound thalamotomy significantly reduced tremor severity and functional disability scores. Adverse events for speech, swallowing, and ataxia were mostly mild and transient.ClinicalTrials.gov Identifier NCT04112381.

  View details for DOI 10.1001/jamaneurol.2024.2295

  View details for PubMedID 39073822

• Translating Molecular Approaches to Oligodendrocyte-Mediated Neurological Circuit Modulation. Brain sciences Song, J., Saglam, A., Zuchero, J. B., Buch, V. P. 2024; 14 (7)

  Abstract

  The central nervous system (CNS) exhibits remarkable adaptability throughout life, enabled by intricate interactions between neurons and glial cells, in particular, oligodendrocytes (OLs) and oligodendrocyte precursor cells (OPCs). This adaptability is pivotal for learning and memory, with OLs and OPCs playing a crucial role in neural circuit development, synaptic modulation, and myelination dynamics. Myelination by OLs not only supports axonal conduction but also undergoes adaptive modifications in response to neuronal activity, which is vital for cognitive processing and memory functions. This review discusses how these cellular interactions and myelin dynamics are implicated in various neurocircuit diseases and disorders such as epilepsy, gliomas, and psychiatric conditions, focusing on how maladaptive changes contribute to disease pathology and influence clinical outcomes. It also covers the potential for new diagnostics and therapeutic approaches, including pharmacological strategies and emerging biomarkers in oligodendrocyte functions and myelination processes. The evidence supports a fundamental role for myelin plasticity and oligodendrocyte functionality in synchronizing neural activity and high-level cognitive functions, offering promising avenues for targeted interventions in CNS disorders.

  View details for DOI 10.3390/brainsci14070648

  View details for PubMedID 39061389

  View details for PubMedCentralID PMC11275066

• Dichotomous frequency-dependent phase synchrony in the sensorimotor network characterizes simplistic movement. Scientific reports Buch, V. P., Brandon, C., Ramayya, A. G., Lucas, T. H., Richardson, A. G. 2024; 14 (1): 11933

  Abstract

  It is hypothesized that disparate brain regions interact via synchronous activity to control behavior. The nature of these interconnected ensembles remains an area of active investigation, and particularly the role of high frequency synchronous activity in simplistic behavior is not well known. Using intracranial electroencephalography, we explored the spectral dynamics and network connectivity of sensorimotor cortical activity during a simple motor task in seven epilepsy patients. Confirming prior work, we see a "spectral tilt" (increased high-frequency (HF, 70-100 Hz) and decreased low-frequency (LF, 3-33 Hz) broadband oscillatory activity) in motor regions during movement compared to rest, as well as an increase in LF synchrony between these regions using time-resolved phase-locking. We then explored this phenomenon in high frequency and found a robust but opposite effect, where time-resolved HF broadband phase-locking significantly decreased during movement. This "connectivity tilt" (increased LF synchrony and decreased HF synchrony) displayed a graded anatomical dependency, with the most robust pattern occurring in primary sensorimotor cortical interactions and less robust pattern occurring in associative cortical interactions. Connectivity in theta (3-7 Hz) and high beta (23-27 Hz) range had the most prominent low frequency contribution during movement, with theta synchrony building gradually while high beta having the most prominent effect immediately following the cue. There was a relatively sharp, opposite transition point in both the spectral and connectivity tilt at approximately 35 Hz. These findings support the hypothesis that task-relevant high-frequency spectral activity is stochastic and that the decrease in high-frequency synchrony may facilitate enhanced low frequency phase coupling and interregional communication. Thus, the "connectivity tilt" may characterize behaviorally meaningful cortical interactions.

  View details for DOI 10.1038/s41598-024-62848-9

  View details for PubMedID 38789576

  View details for PubMedCentralID 2868968

• Emerging Outlook on Personalized Neuromodulation for Depression: Insights from Tractography-Based Targeting. Biological psychiatry. Cognitive neuroscience and neuroimaging Sadeghzadeh, S., Swaminathan, A., Bhanot, P., Steeman, S., Xu, A., Shah, V., Purger, D. A., Buch, V. P. 2024

  Abstract

  Deep brain stimulation (DBS) has shown individual promise in treating treatment resistant depression (TRD), but larger-scale trials have been less successful. Here, we create the largest meta-analysis with individual patient data (IPD) to date to explore if the use of tractography enhances the efficacy of DBS for TRD.We systematically reviewed 1823 articles, selecting 32 that contributed data from 366 patients. We stratified the IPD based on stimulation target and use of tractography. Utilizing two-way type III Analysis of Variance (ANOVA), Welch Two Sample t-tests, and mixed-effects linear regression models, we evaluated changes in depression severity 9-15 months post-surgery (1-Y) and at last follow-up (LFU) (4 weeks - 8 years) as assessed by depression scales.Tractography was used for medial forebrain bundle (MFB, n=17/32), subcallosal cingulate (SCC, n=39/241), and ventral capsule/ventral striatum (VC/VS, n=3/41) targets; and not used for bed nucleus of stria terminalis (n=11), lateral habenula (n=10), and inferior thalamic peduncle (n=1). Across all patients, tractography significantly improved mean depression scores at 1-Y (p<0.001) and LFU (p=0.009). Within the target cohorts, tractography improved depression scores at 1-Y for both MFB and SCC, though significance was only met at the alpha = 0.1 level (SCC: β=15.8%, p=0.09; MFB: β=52.4%, p=0.10). Within the tractography cohort, MFB with tractography patients showed greater improvement than those with SCC with tractography (72.42±7.17% versus 54.78±4.08%) at 1-Y (p=0.044).Our findings underscore the promise of tractography in DBS for TRD as a methodology for personalization of therapy, supporting its inclusion in future trials.

  View details for DOI 10.1016/j.bpsc.2024.04.007

  View details for PubMedID 38679323

• The fasciola cinereum of the hippocampal tail as an interventional target in epilepsy. Nature medicine Jamiolkowski, R. M., Nguyen, Q. A., Farrell, J. S., McGinn, R. J., Hartmann, D. A., Nirschl, J. J., Sanchez, M. I., Buch, V. P., Soltesz, I. 2024

  Abstract

  Targeted tissue ablation involving the anterior hippocampus is the standard of care for patients with drug-resistant mesial temporal lobe epilepsy. However, a substantial proportion continues to suffer from seizures even after surgery. We identified the fasciola cinereum (FC) neurons of the posterior hippocampal tail as an important seizure node in both mice and humans with epilepsy. Genetically defined FC neurons were highly active during spontaneous seizures in epileptic mice, and closed-loop optogenetic inhibition of these neurons potently reduced seizure duration. Furthermore, we specifically targeted and found the prominent involvement of FC during seizures in a cohort of six patients with epilepsy. In particular, targeted lesioning of the FC in a patient reduced the seizure burden present after ablation of anterior mesial temporal structures. Thus, the FC may be a promising interventional target in epilepsy.

  View details for DOI 10.1038/s41591-024-02924-9

  View details for PubMedID 38632391

  View details for PubMedCentralID 3712982

• Ultrasound-Induced Cascade Amplification in a Mechanoluminescent Nanotransducer for Enhanced Sono-Optogenetic Deep Brain Stimulation. ACS nano Wang, W., Kevin Tang, K. W., Pyatnitskiy, I., Liu, X., Shi, X., Huo, D., Jeong, J., Wynn, T., Sangani, A., Baker, A., Hsieh, J. C., Lozano, A. R., Artman, B., Fenno, L., Buch, V. P., Wang, H. 2023

  Abstract

  Remote and genetically targeted neuromodulation in the deep brain is important for understanding and treatment of neurological diseases. Ultrasound-triggered mechanoluminescent technology offers a promising approach for achieving remote and genetically targeted brain modulation. However, its application has thus far been limited to shallow brain depths due to challenges related to low sonochemical reaction efficiency and restricted photon yields. Here we report a cascaded mechanoluminescent nanotransducer to achieve efficient light emission upon ultrasound stimulation. As a result, blue light was generated under ultrasound stimulation with a subsecond response latency. Leveraging the high energy transfer efficiency of focused ultrasound in brain tissue and the high sensitivity to ultrasound of these mechanoluminescent nanotransducers, we are able to show efficient photon delivery and activation of ChR2-expressing neurons in both the superficial motor cortex and deep ventral tegmental area after intracranial injection. Our liposome nanotransducers enable minimally invasive deep brain stimulation for behavioral control in animals via a flexible, mechanoluminescent sono-optogenetic system.

  View details for DOI 10.1021/acsnano.3c06577

  View details for PubMedID 38096422

• Subjective states induced by intracranial electrical stimulation matches the cytoarchitectonic organization of the human insula. Brain stimulation Duong, A., Quabs, J., Kucyi, A., Lusk, Z., Buch, V., Caspers, S., Parvizi, J. 2023

  Abstract

  Functions of the human insula have been explored extensively with neuroimaging methods and intracranial electrical stimulation studies that have highlighted a functional segregation across its subregions. A recently developed cytoarchitectonic map of the human insula has also segregated this brain region into various areas. Our knowledge of the functional organization of this brain region at the level of these fine-parceled microstructural areas remains only partially understood. We address this gap of knowledge by applying a multimodal approach linking direct electrical stimulation and task-evoked intracranial EEG recordings with microstructural subdivisions of the human insular cortex. In 17 neurosurgical patients with 142 implanted electrodes, stimulation of 40 % of the sites induced a reportable change in the conscious experience of the subjects in visceral/autonomic, anxiety, taste/olfactory, pain/temperature as well as somatosensory domains. These subjective responses showed a topographical allocation to microstructural areas defined by probabilistic cytoarchitectonic parcellation maps of the human insula. We found the pain and thermal responses to be located in areas lg2/ld2, while non-painful/non-thermal somatosensory responses corresponded to area ld3 and visceroceptive responses to area Id6. Lastly, the stimulation of area Id7 in the dorsal anterior insula, failed to induce reportable changes to subjective experience even though intracranial EEG recordings from this region captured significant time-locked high-frequency activity (HFA. Our results provide a multimodal map of functional subdivisions within the human insular cortex at the individual brain basis and characterize their anatomical association with fine-grained cytoarchitectonic parcellations of this brain structure.

  View details for DOI 10.1016/j.brs.2023.11.001

  View details for PubMedID 37949296

• Developing the surgeon-machine interface: using a novel instance-segmentation framework for intraoperative landmark labelling. Frontiers in surgery Park, J. J., Doiphode, N., Zhang, X., Pan, L., Blue, R., Shi, J., Buch, V. P. 2023; 10: 1259756

  Abstract

  The utilisation of artificial intelligence (AI) augments intraoperative safety, surgical training, and patient outcomes. We introduce the term Surgeon-Machine Interface (SMI) to describe this innovative intersection between surgeons and machine inference. A custom deep computer vision (CV) architecture within a sparse labelling paradigm was developed, specifically tailored to conceptualise the SMI. This platform demonstrates the ability to perform instance segmentation on anatomical landmarks and tools from a single open spinal dural arteriovenous fistula (dAVF) surgery video dataset.Our custom deep convolutional neural network was based on SOLOv2 architecture for precise, instance-level segmentation of surgical video data. Test video consisted of 8520 frames, with sparse labelling of only 133 frames annotated for training. Accuracy and inference time, assessed using F1-score and mean Average Precision (mAP), were compared against current state-of-the-art architectures on a separate test set of 85 additionally annotated frames.Our SMI demonstrated superior accuracy and computing speed compared to these frameworks. The F1-score and mAP achieved by our platform were 17% and 15.2% respectively, surpassing MaskRCNN (15.2%, 13.9%), YOLOv3 (5.4%, 11.9%), and SOLOv2 (3.1%, 10.4%). Considering detections that exceeded the Intersection over Union threshold of 50%, our platform achieved an impressive F1-score of 44.2% and mAP of 46.3%, outperforming MaskRCNN (41.3%, 43.5%), YOLOv3 (15%, 34.1%), and SOLOv2 (9%, 32.3%). Our platform demonstrated the fastest inference time (88ms), compared to MaskRCNN (90ms), SOLOV2 (100ms), and YOLOv3 (106ms). Finally, the minimal amount of training set demonstrated a good generalisation performance -our architecture successfully identified objects in a frame that were not included in the training or validation frames, indicating its ability to handle out-of-domain scenarios.We present our development of an innovative intraoperative SMI to demonstrate the future promise of advanced CV in the surgical domain. Through successful implementation in a microscopic dAVF surgery, our framework demonstrates superior performance over current state-of-the-art segmentation architectures in intraoperative landmark guidance with high sample efficiency, representing the most advanced AI-enabled surgical inference platform to date. Our future goals include transfer learning paradigms for scaling to additional surgery types, addressing clinical and technical limitations for performing real-time decoding, and ultimate enablement of a real-time neurosurgical guidance platform.

  View details for DOI 10.3389/fsurg.2023.1259756

  View details for PubMedID 37936949

  View details for PubMedCentralID PMC10626480

• Accumbens connectivity during deep-brain stimulation differentiates loss of control from physiologic behavioral states. Brain stimulation Rolle, C. E., Ng, G. Y., Nho, Y. H., Barbosa, D. A., Shivacharan, R. S., Gold, J. I., Bassett, D. S., Halpern, C. H., Buch, V. 2023

  Abstract

  Loss of control (LOC) eating, the subjective sense that one cannot control what or how much one eats, characterizes binge-eating behaviors pervasive in obesity and related eating disorders. Closed-loop deep-brain stimulation (DBS) for binge eating should predict LOC and trigger an appropriately timed intervention.This study aimed to identify a sensitive and specific biomarker to detect LOC onset for DBS. We hypothesized that changes in phase-locking value (PLV) predict the onset of LOC-associated cravings and distinguish them from potential confounding states.Using DBS data recorded from the nucleus accumbens (NAc) of two patients with binge eating disorder (BED) and severe obesity, we compared PLV between inter- and intra-hemispheric NAc subregions for three behavioral conditions: craving (associated with LOC eating), hunger (not associated with LOC), and sleep.In both patients, PLV in the high gamma frequency band was significantly higher for craving compared to sleep and significantly higher for hunger compared to craving. Maximum likelihood classifiers achieved accuracies above 88% when differentiating between the three conditions.High-frequency inter- and intra-hemispheric PLV in the NAc is a promising biomarker for closed-loop DBS that differentiates LOC-associated cravings from physiologic states such as hunger and sleep. Future trials should assess PLV as a LOC biomarker across a larger cohort and a wider patient population transdiagnostically.

  View details for DOI 10.1016/j.brs.2023.09.010

  View details for PubMedID 37734587

• Long-term outcomes of mesial temporal laser interstitial thermal therapy for drug-resistant epilepsy and subsequent surgery for seizure recurrence: a multi-centre cohort study. Journal of neurology, neurosurgery, and psychiatry Youngerman, B. E., Banu, M. A., Khan, F., McKhann, G. M., Schevon, C. A., Jagid, J. R., Cajigas, I., Theodotou, C. B., Ko, A., Buckley, R., Ojemann, J. G., Miller, J. W., Laxton, A. W., Couture, D. E., Popli, G. S., Buch, V. P., Halpern, C. H., Le, S., Sharan, A. D., Sperling, M. R., Mehta, A. D., Englot, D. J., Neimat, J. S., Konrad, P. E., Sheth, S. A., Neal, E. G., Vale, F. L., Holloway, K. L., Air, E. L., Schwalb, J. M., D'Haese, P., Wu, C. 2023

  Abstract

  BACKGROUND: Magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) is a minimally invasive alternative to surgical resection for drug-resistant mesial temporal lobe epilepsy (mTLE). Reported rates of seizure freedom are variable and long-term durability is largely unproven. Anterior temporal lobectomy (ATL) remains an option for patients with MRgLITT treatment failure. However, the safety and efficacy of this staged strategy is unknown.METHODS: This multicentre, retrospective cohort study included 268 patients consecutively treated with mesial temporal MRgLITT at 11 centres between 2012 and 2018. Seizure outcomes and complications of MRgLITT and any subsequent surgery are reported. Predictive value of preoperative variables for seizure outcome was assessed.RESULTS: Engel I seizure freedom was achieved in 55.8% (149/267) at 1year, 52.5% (126/240) at 2 years and 49.3% (132/268) at the last follow-up ≥1year (median 47 months). Engel I or II outcomes were achieved in 74.2% (198/267) at 1year, 75.0% (180/240) at 2 years and 66.0% (177/268) at the last follow-up. Preoperative focal to bilateral tonic-clonic seizures were independently associated with seizure recurrence. Among patients with seizure recurrence, 14/21 (66.7%) became seizure-free after subsequent ATL and 5/10 (50%) after repeat MRgLITT at last follow-up≥1year.CONCLUSIONS: MRgLITT is a viable treatment with durable outcomes for patients with drug-resistant mTLE evaluated at a comprehensive epilepsy centre. Although seizure freedom rates were lower than reported with ATL, this series represents the early experience of each centre and a heterogeneous cohort. ATL remains a safe and effective treatment for well-selected patients who fail MRgLITT.

  View details for DOI 10.1136/jnnp-2022-330979

  View details for PubMedID 37336643

• Causal evidence for the processing of bodily self in the anterior precuneus. Neuron Lyu, D., Stieger, J. R., Xin, C., Ma, E., Lusk, Z., Aparicio, M. K., Werbaneth, K., Perry, C. M., Deisseroth, K., Buch, V., Parvizi, J. 2023

  Abstract

  To probe the causal importance of the human posteromedial cortex (PMC) in processing the sense of self, we studied a rare cohort of nine patients with electrodes implanted bilaterally in the precuneus, posterior cingulate, and retrosplenial regions with a combination of neuroimaging, intracranial recordings, and direct cortical stimulations. In all participants, the stimulation of specific sites within the anterior precuneus (aPCu) caused dissociative changes in physical and spatial domains. Using single-pulse electrical stimulations and neuroimaging, we present effective and resting-state connectivity of aPCu hot zone with the rest of the brain and show that they are located outside the boundaries of the default mode network (DMN) but connected reciprocally with it. We propose that the function of this subregion of the PMC is integral to a range of cognitive processes that require the self's physical point of reference, given its location within a spatial environment.

  View details for DOI 10.1016/j.neuron.2023.05.013

  View details for PubMedID 37295420

• Multisite thalamic recordings to characterize seizure propagation in the human brain. Brain : a journal of neurology Wu, T. Q., Kaboodvand, N., McGinn, R. J., Veit, M., Davey, Z., Datta, A., Graber, K. D., Meador, K. J., Fisher, R., Buch, V., Parvizi, J. 2023

  Abstract

  Neuromodulation of the anterior nuclei of the thalamus (ANT) has shown to be efficacious in a subset of patients with refractory focal epilepsy. One important uncertainty is to what extent thalamic subregions other than the ANT could be recruited more prominently in the propagation of focal onset seizures. We designed the current study to simultaneously monitor the engagement of the ANT, mediodorsal (MD) and pulvinar (PUL) nuclei during seizures in patients who could be candidates for thalamic neuromodulation. We studied 11 patients with clinical manifestations of presumed temporal lobe epilepsy (TLE) undergoing invasive stereo-encephalography (sEEG) monitoring to confirm the source of their seizures. We extended cortical electrodes to reach the ANT, MD and PUL nuclei of the thalamus. More than one thalamic subdivision was simultaneously interrogated in nine patients. We recorded seizures with implanted electrodes across various regions of the brain and documented seizure onset zones (SOZ) in each recorded seizure. We visually identified the first thalamic subregion to be involved in seizure propagation. Additionally, in eight patients, we applied repeated single pulse electrical stimulation in each SOZ and recorded the time and prominence of evoked responses across the implanted thalamic regions. Our approach for multisite thalamic sampling was safe and caused no adverse events. Intracranial EEG recordings confirmed SOZ in medial temporal lobe, insula, orbitofrontal and temporal neocortical sites, highlighting the importance of invasive monitoring for accurate localization of SOZs. In all patients, seizures with the same propagation network and originating from the same SOZ involved the same thalamic subregion, with a stereotyped thalamic EEG signature. Qualitative visual reviews of ictal EEGs were largely consistent with the quantitative analysis of the corticothalamic evoked potentials, and both documented that thalamic nuclei other than ANT could have the earliest participation in seizure propagation. Specifically, pulvinar nuclei were involved earlier and more prominently than ANT in more than half of the patients. However, which specific thalamic subregion first demonstrated ictal activity could not be reliably predicted based on clinical semiology or lobar localization of SOZs. Our findings document the feasibility and safety of bilateral multisite sampling from the human thalamus. This may allow more personalized thalamic targets to be identified for neuromodulation. Future studies are needed to determine if a personalized thalamic neuromodulation leads to greater improvements in clinical outcome.

  View details for DOI 10.1093/brain/awad121

  View details for PubMedID 37137813

• Taking modern psychiatry into the metaverse: Integrating augmented, virtual, and mixed reality technologies into psychiatric care. Frontiers in digital health Ford, T. J., Buchanan, D. M., Azeez, A., Benrimoh, D. A., Kaloiani, I., Bandeira, I. D., Hunegnaw, S., Lan, L., Gholmieh, M., Buch, V., Williams, N. R. 2023; 5: 1146806

  Abstract

  The landscape of psychiatry is ever evolving and has recently begun to be influenced more heavily by new technologies. One novel technology which may have particular application to psychiatry is the metaverse, a three-dimensional digital social platform accessed via augmented, virtual, and mixed reality (AR/VR/MR). The metaverse allows the interaction of users in a virtual world which can be measured and manipulated, posing at once exciting new possibilities and significant potential challenges and risks. While the final form of the nascent metaverse is not yet clear, the immersive simulation and holographic mixed reality-based worlds made possible by the metaverse have the potential to redefine neuropsychiatric care for both patients and their providers. While a number of applications for this technology can be envisioned, this article will focus on leveraging the metaverse in three specific domains: medical education, brain stimulation, and biofeedback. Within medical education, the metaverse could allow for more precise feedback to students performing patient interviews as well as the ability to more easily disseminate highly specialized technical skills, such as those used in advanced neurostimulation paradigms. Examples of potential applications in brain stimulation and biofeedback range from using AR to improve precision targeting of non-invasive neuromodulation modalities to more innovative practices, such as using physiological and behavioral measures derived from interactions in VR environments to directly inform and personalize treatment parameters for patients. Along with promising future applications, we also discuss ethical implications and data security concerns that arise when considering the introduction of the metaverse and related AR/VR technologies to psychiatric research and care.

  View details for DOI 10.3389/fdgth.2023.1146806

  View details for PubMedID 37035477

  View details for PubMedCentralID PMC10080019

• Pilot study of responsive nucleus accumbens deep brain stimulation for loss-of-control eating. Nature medicine Shivacharan, R. S., Rolle, C. E., Barbosa, D. A., Cunningham, T. N., Feng, A., Johnson, N. D., Safer, D. L., Bohon, C., Keller, C., Buch, V. P., Parker, J. J., Azagury, D. E., Tass, P. A., Bhati, M. T., Malenka, R. C., Lock, J. D., Halpern, C. H. 2022

  Abstract

  Cravings that precede loss of control (LOC) over food consumption present an opportunity for intervention in patients with the binge eating disorder (BED). In this pilot study, we used responsive deep brain stimulation (DBS) to record nucleus accumbens (NAc) electrophysiology during food cravings preceding LOC eating in two patients with BED and severe obesity (trial registration no. NCT03868670). Increased NAc low-frequency oscillations, prominent during food cravings, were used to guide DBS delivery. Over 6 months, we observed improved self-control of food intake and weight loss. These findings provide early support for restoring inhibitory control with electrophysiologically-guided NAc DBS. Further work with increased sample sizes is required to determine the scalability of this approach.

  View details for DOI 10.1038/s41591-022-01941-w

  View details for PubMedID 36038628

• Magnetic resonance imaging-guided laser interstitial thermal therapy for refractory focal epilepsy in a patient with a fully implanted RNS system: illustrative case. Journal of neurosurgery. Case lessons Buch, V. P., Mirro, E. A., Purger, D. A., Zeineh, M., Wilmer-Fierro, K., Razavi, B., Halpern, C. H. 2022; 3 (21): CASE22117

  Abstract

  BACKGROUND: The resective surgery plus responsive neurostimulation (RNS) system is an effective treatment for patients with refractory focal epilepsy. Furthermore, the long-term intracranial electroencephalography data provided by the system can inform a future resection or ablation procedure. RNS patients may undergo 1.5-T magnetic resonance imaging (MRI) under the conditions specified in the RNS system MRI guidelines; however, it was unknown if the MRI artifact would limit intraoperative laser interstitial thermal therapy (LITT) in a patient with a fully implanted RNS system.OBSERVATIONS: The authors were able to complete a successful awake LITT of epileptogenic tissue in a 1.5-T MRI scanner on the ipsilateral side to an implanted RNS system.LESSONS: If a future LITT procedure is probable, the neurostimulator should be placed contralateral to the side of the potential ablation. Using twist drill holes versus burr holes for depth lead placement may assist in future laser bone anchor seating. Before a LITT procedure in a patient with the neurostimulator ipsilateral to the ablation, 1.5-T MRI thermography scanning should be scheduled preoperatively to assess artifact in the proposed ablation zone. Per the RNS system MRI guidelines, the patient must be positioned supine and awake, with no more than 30 minutes of active scan time before a 30-minute pause.

  View details for DOI 10.3171/CASE22117

  View details for PubMedID 35734233

• How the Brain Anticipates: From Neurons to Networks Ramayya, A. G., Buch, V., Richardson, A., Lucas, T., Gold, J. AMER ASSOC NEUROLOGICAL SURGEONS. 2022

  View details for Web of Science ID 001132701400094

• Conversion to Hybrid Deep Brain Stimulation System to Enable Multi-Contact Fractionation Can be Therapeutic. Movement disorders : official journal of the Movement Disorder Society Ojukwu, D. I., Wang, A. R., Hornbeck, T. S., Lim, E. A., Sharrard, J., Dhall, R., Buch, V. P., Halpern, C. H. 2022

  View details for DOI 10.1002/mds.29007

  View details for PubMedID 35393689

• Network Brain-Computer Interface (nBCI): An Alternative Approach for Cognitive Prosthetics FRONTIERS IN NEUROSCIENCE Buch, V. P., Richardson, A. G., Brandon, C., Stiso, J., Khattak, M. N., Bassett, D. S., Lucas, T. H. 2018; 12: 790

  Abstract

  Brain computer interfaces (BCIs) have been applied to sensorimotor systems for many years. However, BCI technology has broad potential beyond sensorimotor systems. The emerging field of cognitive prosthetics, for example, promises to improve learning and memory for patients with cognitive impairment. Unfortunately, our understanding of the neural mechanisms underlying these cognitive processes remains limited in part due to the extensive individual variability in neural coding and circuit function. As a consequence, the development of methods to ascertain optimal control signals for cognitive decoding and restoration remains an active area of inquiry. To advance the field, robust tools are required to quantify time-varying and task-dependent brain states predictive of cognitive performance. Here, we suggest that network science is a natural language in which to formulate and apply such tools. In support of our argument, we offer a simple demonstration of the feasibility of a network approach to BCI control signals, which we refer to as network BCI (nBCI). Finally, in a single subject example, we show that nBCI can reliably predict online cognitive performance and is superior to certain common spectral approaches currently used in BCIs. Our review of the literature and preliminary findings support the notion that nBCI could provide a powerful approach for future applications in cognitive prosthetics.

  View details for DOI 10.3389/fnins.2018.00790

  View details for Web of Science ID 000449007900001

  View details for PubMedID 30443203

  View details for PubMedCentralID PMC6221897

• Navigated peel-away sheath assisted placement of fully pre-assembled Ommaya reservoir systems: Technical note. World neurosurgery: X Wathen, C. A., Punchak, M., Madsen, P., Vaughan, K., Buch, V., Marcotte, P. J. 2024; 23: 100295

  View details for DOI 10.1016/j.wnsx.2024.100295

  View details for PubMedID 38497062

• Causal Cortical and Thalamic Connections in the Human Brain. bioRxiv : the preprint server for biology Lyu, D., Stiger, J., Lusk, Z., Buch, V., Parvizi, J. 2024

  Abstract

  The brain's functional architecture is intricately shaped by causal connections between its cortical and subcortical structures. Here, we studied 27 participants with 4864 electrodes implanted across the anterior, mediodorsal, and pulvinar thalamic regions, and the cortex. Using data from electrical stimulation procedures and a data-driven approach informed by neurophysiological standards, we dissociated three unique spectral patterns generated by the perturbation of a given brain area. Among these, a novel waveform emerged, marked by delayed-onset slow oscillations in both ipsilateral and contralateral cortices following thalamic stimulations, suggesting a mechanism by which a thalamic site can influence bilateral cortical activity. Moreover, cortical stimulations evoked earlier signals in the thalamus than in other connected cortical areas suggesting that the thalamus receives a copy of signals before they are exchanged across the cortex. Our causal connectivity data can be used to inform biologically-inspired computational models of the functional architecture of the brain.

  View details for DOI 10.1101/2024.06.22.600166

  View details for PubMedID 38979261

  View details for PubMedCentralID PMC11230252

• Rates and Predictors of Pain Reduction With Intracranial Stimulation for Intractable Pain Disorders. Neurosurgery Huang, Y., Sadeghzadeh, S., Li, A. H., Schonfeld, E., Ramayya, A. G., Buch, V. P. 2024

  Abstract

  Intracranial modulation paradigms, namely deep brain stimulation (DBS) and motor cortex stimulation (MCS), have been used to treat intractable pain disorders. However, treatment efficacy remains heterogeneous, and factors associated with pain reduction are not completely understood.We performed an individual patient review of pain outcomes (visual analog scale, quality-of-life measures, complications, pulse generator implant rate, cessation of stimulation) after implantation of DBS or MCS devices. We evaluated 663 patients from 36 study groups and stratified outcomes by pain etiology and implantation targets.Included studies comprised primarily retrospective cohort studies. MCS patients had a similar externalized trial success rate compared with DBS patients (86% vs 81%; P = .16), whereas patients with peripheral pain had a higher trial success rate compared with patients with central pain (88% vs 79%; P = .004). Complication rates were similar for MCS and DBS patients (12% vs 15%; P = .79). Patients with peripheral pain had lower likelihood of device cessation compared with those with central pain (5.7% vs 10%; P = .03). Of all implanted patients, mean pain reduction at last follow-up was 45.8% (95% CI: 40.3-51.2) with a 31.2% (95% CI: 12.4-50.1) improvement in quality of life. No difference was seen between MCS patients (43.8%; 95% CI: 36.7-58.2) and DBS patients (48.6%; 95% CI: 39.2-58) or central (41.5%; 95% CI: 34.8-48.2) and peripheral (46.7%; 95% CI: 38.9-54.5) etiologies. Multivariate analysis identified the anterior cingulate cortex target to be associated with worse pain reduction, while postherpetic neuralgia was a positive prognostic factor.Both DBS and MCS have similar efficacy and complication rates in the treatment of intractable pain. Patients with central pain disorders tended to have lower trial success and higher rates of device cessation. Additional prognostic factors include anterior cingulate cortex targeting and postherpetic neuralgia diagnosis. These findings underscore intracranial neurostimulation as an important modality for treatment of intractable pain disorders.

  View details for DOI 10.1227/neu.0000000000003006

  View details for PubMedID 38836613

• Causal Cortical and Thalamic Connections in the Human Brain. Research square Parvizi, J., Lyu, D., Stieger, J., Lusk, Z., Buch, V. 2024

  Abstract

  The brain's functional architecture is intricately shaped by causal connections between its cortical and subcortical structures. Here, we studied 27 participants with 4864 electrodes implanted across the anterior, mediodorsal, and pulvinar thalamic regions, and the cortex. Using data from electrical stimulation procedures and a data-driven approach informed by neurophysiological standards, we dissociated three unique spectral patterns generated by the perturbation of a given brain area. Among these, a novel waveform emerged, marked by delayed-onset slow oscillations in both ipsilateral and contralateral cortices following thalamic stimulations, suggesting a mechanism by which a thalamic site can influence bilateral cortical activity. Moreover, cortical stimulations evoked earlier signals in the thalamus than in other connected cortical areas suggesting that the thalamus receives a copy of signals before they are exchanged across the cortex. Our causal connectivity data can be used to inform biologically-inspired computational models of the functional architecture of the brain.

  View details for DOI 10.21203/rs.3.rs-4366486/v1

  View details for PubMedID 38853954

  View details for PubMedCentralID PMC11160924

• Naturalistic acute pain states decoded from neural and facial dynamics. bioRxiv : the preprint server for biology Huang, Y., Gopal, J., Kakusa, B., Li, A. H., Huang, W., Wang, J. B., Persad, A., Ramayya, A., Parvizi, J., Buch, V. P., Keller, C. 2024

  Abstract

  Pain is a complex experience that remains largely unexplored in naturalistic contexts, hindering our understanding of its neurobehavioral representation in ecologically valid settings. To address this, we employed a multimodal, data-driven approach integrating intracranial electroencephalography, pain self-reports, and facial expression quantification to characterize the neural and behavioral correlates of naturalistic acute pain in twelve epilepsy patients undergoing continuous monitoring with neural and audiovisual recordings. High self-reported pain states were associated with elevated blood pressure, increased pain medication use, and distinct facial muscle activations. Using machine learning, we successfully decoded individual participants' high versus low self-reported pain states from distributed neural activity patterns (mean AUC = 0.70), involving mesolimbic regions, striatum, and temporoparietal cortex. High self-reported pain states exhibited increased low-frequency activity in temporoparietal areas and decreased high-frequency activity in mesolimbic regions (hippocampus, cingulate, and orbitofrontal cortex) compared to low pain states. This neural pain representation remained stable for hours and was modulated by pain onset and relief. Objective facial expression changes also classified self-reported pain states, with results concordant with electrophysiological predictions. Importantly, we identified transient periods of momentary pain as a distinct naturalistic acute pain measure, which could be reliably differentiated from affect-neutral periods using intracranial and facial features, albeit with neural and facial patterns distinct from self-reported pain. These findings reveal reliable neurobehavioral markers of naturalistic acute pain across contexts and timescales, underscoring the potential for developing personalized pain interventions in real-world settings.

  View details for DOI 10.1101/2024.05.10.593652

  View details for PubMedID 38766098

  View details for PubMedCentralID PMC11100805

• Dosimetric Comparison of Dedicated Radiosurgery Platforms for the Treatment of Essential Tremor: Technical Report. Cureus Marianayagam, N. J., Paddick, I., Persad, A. R., Hori, Y. S., Maslowski, A., Thirunarayanan, I., Khanna, A. R., Park, D. J., Buch, V., Chang, S. D., Schneider, M. B., Yu, H., Weidlich, G. A., Adler, J. R. 2024; 16 (4): e57452

  Abstract

  Essential tremor (ET) is one of the most common adult movement disorders. As the worldwide population ages, the incidence and prevalence of ET is increasing. Although most cases can be managed conservatively, there is a subset of ET that is refractory to medical management. By virtue of being "reversible", deep brain stimulation (DBS) of the ventral intermediate nucleus (VIM) of the thalamus is one commonly accepted intervention. As an alternative to invasive and expensive DBS, there has been a renaissance in treating ET with lesion-based approaches, spearheaded most recently by high-intensity focused ultrasound (HIFU), the hallmark of which is that it is non-invasive. Meanwhile, stereotactic radiosurgical (SRS) lesioning of VIM represents another time-honored lesion-based non-invasive treatment of ET, which is especially well suited for those patients that cannot tolerate open neurosurgery and is now also getting a "second look". While multiple SRS platforms have been and continue to be used to treat ET, there is little in the way of dosimetric comparison between different technologies. In this brief technical report we compare the dosimetric profiles of three major radiosurgical platforms (Gamma Knife, CyberKnife Robotic Radiosurgery, and Zap-X Gyroscopic Radiosurgery (GRS)) for the treatment of ET. In general, the GRS and Gamma Knife were shown to have the best theoretical dosimetric profiles for VIM lesioning. Nevertheless the relevance of such superiority to clinical outcomes requires future patient studies.

  View details for DOI 10.7759/cureus.57452

  View details for PubMedID 38699125

  View details for PubMedCentralID PMC11064878

• Evolution of SEEG Strategy: Stanford Experience. Neurosurgery clinics of North America Buch, V. P., Parvizi, J. 2024; 35 (1): 83-85

  Abstract

  Overall stereoelectroencephalography (SEEG) has a favorable risk profile, patient tolerability, and superior investigative capability of individualized 3-dimensional seizure onset activity over subdural electrodes. Further, our recent surgical approach to safely enable multinuclear thalamic propagation mapping can only be performed with SEEG. For these reasons, SEEG has become the gold standard of phase II monitoring at our institution, and believe the ability to develop precision network-centric approaches to therapy will be critical to enhance our ability to care for medically refractory, and importantly, even complex multifocal, generalized, or surgically refractory epilepsy patients.

  View details for DOI 10.1016/j.nec.2023.08.003

  View details for PubMedID 38000844

• An Individualized Tractography Pipeline for the Nucleus Basalis of Meynert Lateral Tract. medRxiv : the preprint server for health sciences Crockett, R. A., Wilkins, K. B., Zeineh, M. M., McNab, J. A., Henderson, J. M., Buch, V. P., Brontë-Stewart, H. M. 2023

  Abstract

  At the center of the cortical cholinergic network, the nucleus basalis of Meynert (NBM) is crucial for the cognitive domains most vulnerable in PD. Preclinical evidence has demonstrated the positive impact of NBM deep brain stimulation (DBS) on cognition but early human trials have had mixed results. It is possible that DBS of the lateral NBM efferent white matter fiber bundle may be more effective at improving cognitive-motor function. However, precise tractography modelling is required to identify the optimal target for neurosurgical planning. Individualized tractography approaches have been shown to be highly effective for accurately identifying DBS targets but have yet to be developed for the NBM.Using structural and diffusion weighted imaging, we developed a tractography pipeline for precise individualized identification of the lateral NBM target tract. Using dice similarity coefficients, the reliability of the tractography outputs was assessed across three cohorts to investigate: 1) whether this manual pipeline is more reliable than an existing automated pipeline currently used in the literature; 2) the inter- and intra-rater reliability of our pipeline in research scans of patients with PD; and 3) the reliability and practicality of this pipeline in clinical scans of DBS patients.The individualized manual pipeline was found to be significantly more reliable than the existing automated pipeline for both the segmentation of the NBM region itself (p<0.001) and the reconstruction of the target lateral tract (p=0.002). There was also no significant difference between the reliability of two different raters in the PD cohort (p=0.25), which showed high inter- (mean Dice coefficient >0.6) and intra-rater (mean Dice coefficient >0.7) reliability across runs. Finally, the pipeline was shown to be highly reliable within the clinical scans (mean Dice coefficient = 0.77). However, accurate reconstruction was only evident in 7/10 tracts.We have developed a reliable tractography pipeline for the identification and analysis of the NBM lateral tract in research and clinical grade imaging of healthy young adult and PD patient scans.

  View details for DOI 10.1101/2023.08.31.23294922

  View details for PubMedID 37693520

  View details for PubMedCentralID PMC10491381

• Predicting Sedation Level using Surface and Intracranial EEG with Convolutional Neural Networks during Emergence from Anesthesia Han, L., Purger, D., Eagleman, S., Halpern, C., Buch, V., Razavi, B., Meador, K., Drover, D. LIPPINCOTT WILLIAMS & WILKINS. 2023: 583-585

  View details for Web of Science ID 001058985600203

• Beyond mAP: Towards better evaluation of instance segmentation Jena, R., Zhornyak, L., Doiphode, N., Chaudhari, P., Buch, V., Gee, J., Shi, J., IEEE IEEE COMPUTER SOC. 2023: 11309-11318

  View details for DOI 10.1109/CVPR52729.2023.01088

  View details for Web of Science ID 001062522103059

• Methods and Impact for Using Federated Learning to Collaborate on Clinical Research. Neurosurgery Cheung, A. T., Nasir-Moin, M., Fred Kwon, Y. J., Guan, J., Liu, C., Jiang, L., Raimondo, C., Chotai, S., Chambless, L., Ahmad, H. S., Chauhan, D., Yoon, J. W., Hollon, T., Buch, V., Kondziolka, D., Chen, D., Al-Aswad, L. A., Aphinyanaphongs, Y., Oermann, E. K. 2022

  Abstract

  BACKGROUND: The development of accurate machine learning algorithms requires sufficient quantities of diverse data. This poses a challenge in health care because of the sensitive and siloed nature of biomedical information. Decentralized algorithms through federated learning (FL) avoid data aggregation by instead distributing algorithms to the data before centrally updating one global model.OBJECTIVE: To establish a multicenter collaboration and assess the feasibility of using FL to train machine learning models for intracranial hemorrhage (ICH) detection without sharing data between sites.METHODS: Five neurosurgery departments across the United States collaborated to establish a federated network and train a convolutional neural network to detect ICH on computed tomography scans. The global FL model was benchmarked against a standard, centrally trained model using a held-out data set and was compared against locally trained models using site data.RESULTS: A federated network of practicing neurosurgeon scientists was successfully initiated to train a model for predicting ICH. The FL model achieved an area under the ROC curve of 0.9487 (95% CI 0.9471-0.9503) when predicting all subtypes of ICH compared with a benchmark (non-FL) area under the ROC curve of 0.9753 (95% CI 0.9742-0.9764), although performance varied by subtype. The FL model consistently achieved top three performance when validated on any site's data, suggesting improved generalizability. A qualitative survey described the experience of participants in the federated network.CONCLUSION: This study demonstrates the feasibility of implementing a federated network for multi-institutional collaboration among clinicians and using FL to conduct machine learning research, thereby opening a new paradigm for neurosurgical collaboration.

  View details for DOI 10.1227/neu.0000000000002198

  View details for PubMedID 36399428

• Do-It-Yourself Augmented Reality Heads-Up Display (DIY AR-HUD): A Technical Note. International journal of spine surgery Yoon, J. W., Spadola, M., Blue, R., Saylany, A., Sharma, N., Ahmad, H. S., Buch, V., Madhavan, K., Chen, H. I., Steinmetz, M. P., Welch, W. C., Malhotra, N. R. 2021

  Abstract

  We present a "Do-It-Yourself" method to build an affordable augmented reality heads-up display system (AR-HUD) capable of displaying intraoperative images. All components are commercially available products, which the surgeons may use in their own practice for educational and research purposes.Moverio BT 35-E smart glasses were connected to operating room imaging modalities (ie, fluoroscopy and 3D navigation platforms) via a high-definition multimedia interface (HDMI) converter, allowing for continuous high-definition video transmission. The addition of an HDMI transmitter-receiver makes the AR-HUD system wireless.We used our AR-HUD system in 3 patients undergoing instrumented spinal fusion. AR-HUD projected fluoroscopy images onto the surgical field, eliminating shift of surgeon focus and procedure interruption, with only a 40- to 100-ms delay in transmission, which was not clinically impactful.An affordable AR-HUD capable of displaying real-time information into the surgeon's view can be easily designed, built, and tested in surgical practice. As wearable heads-up display technology continues to evolve rapidly, individual components presented here may be substituted to improve its functionality and usability. Surgeons are in a unique position to conduct clinical testing in the operating room environment to optimize the augmented reality system for surgical use.

  View details for DOI 10.14444/8106

  View details for PubMedID 34266938

• Theta Synchrony Is Increased near Neural Populations That Are Active When Initiating Instructed Movement ENEURO Ramayya, A. G., Yang, A., Buch, V. P., Burke, J. F., Richardson, A. G., Brandon, C., Stein, J. M., Davis, K. A., Chen, H., Proekt, A., Kelz, M. B., Litt, B., Gold, J., Lucas, T. H. 2021; 8 (1)

  Abstract

  Theta oscillations (3-8 Hz) in the human brain have been linked to perception, cognitive control, and spatial memory, but their relation to the motor system is less clear. We tested the hypothesis that theta oscillations coordinate distributed behaviorally relevant neural representations during movement using intracranial electroencephalography (iEEG) recordings from nine patients (n = 490 electrodes) as they performed a simple instructed movement task. Using high frequency activity (HFA; 70-200 Hz) as a marker of local spiking activity, we identified electrodes that were positioned near neural populations that showed increased activity during instruction and movement. We found that theta synchrony was widespread throughout the brain but was increased near regions that showed movement-related increases in neural activity. These results support the view that theta oscillations represent a general property of brain activity that may also play a specific role in coordinating widespread neural activity when initiating voluntary movement.

  View details for DOI 10.1523/ENEURO.0252-20.2020

  View details for Web of Science ID 000641651800015

  View details for PubMedID 33355232

  View details for PubMedCentralID PMC7901148

• Focused ultrasound for functional neurosurgery. Journal of neuro-oncology Lev-Tov, L., Barbosa, D. A., Ghanouni, P., Halpern, C. H., Buch, V. P. 2021

  Abstract

  Brain lesioning is a fundamental technique in the functional neurosurgery world. It has been investigated for decades and presented promising results long before novel pharmacological agents were introduced to treat movement disorders, psychiatric disorders, pain, and epilepsy. Ablative procedures were replaced by effective drugs during the 1950s and by Deep Brain Stimulation (DBS) in the 1990s as a reversible neuromodulation technique. In the last decade, however, the popularity of brain lesioning has increased again with the introduction of magnetic resonance-guided focused ultrasound (MRgFUS).In this review, we will cover the current and emerging role of MRgFUS in functional neurosurgery.Literature review from PubMed and compilation.Investigated since 1930, MRgFUS is a technology enabling targeted energy delivery at the convergence of mechanical sound waves. Based on technological advancements in phased array ultrasound transducers, algorithms accounting for skull penetration by sound waves, and MR imaging for targeting and thermometry, MRgFUS is capable of brain lesioning with sub-millimeter precision and can be used in a variety of clinical indications.MRgFUS is a promising technology evolving as a dominant tool in different functional neurosurgery procedures in movement disorders, psychiatric disorders, epilepsy, among others.

  View details for DOI 10.1007/s11060-021-03818-3

  View details for PubMedID 34383232

• Development of an Intraoperative Pipeline for Holographic Mixed Reality Visualization During Spinal Fusion Surgery SURGICAL INNOVATION Buch, V. P., Mensah-Brown, K. G., Germi, J. W., Park, B. J., Madsen, P. J., Borja, A. J., Haldar, D., Basenfelder, P., Yoon, J. W., Schuster, J. M., Chen, H. I. 2020: 1553350620984339

  Abstract

  Objective. Holographic mixed reality (HMR) allows for the superimposition of computer-generated virtual objects onto the operator's view of the world. Innovative solutions can be developed to enable the use of this technology during surgery. The authors developed and iteratively optimized a pipeline to construct, visualize, and register intraoperative holographic models of patient landmarks during spinal fusion surgery. Methods. The study was carried out in two phases. In phase 1, the custom intraoperative pipeline to generate patient-specific holographic models was developed over 7 patients. In phase 2, registration accuracy was optimized iteratively for 6 patients in a real-time operative setting. Results. In phase 1, an intraoperative pipeline was successfully employed to generate and deploy patient-specific holographic models. In phase 2, the registration error with the native hand-gesture registration was 20.2 ± 10.8 mm (n = 7 test points). Custom controller-based registration significantly reduced the mean registration error to 4.18 ± 2.83 mm (n = 24 test points, P < .01). Accuracy improved over time (B = -.69, P < .0001) with the final patient achieving a registration error of 2.30 ± .58 mm. Across both phases, the average model generation time was 18.0 ± 6.1 minutes (n = 6) for isolated spinal hardware and 33.8 ± 8.6 minutes (n = 6) for spinal anatomy. Conclusions. A custom pipeline is described for the generation of intraoperative 3D holographic models during spine surgery. Registration accuracy dramatically improved with iterative optimization of the pipeline and technique. While significant improvements and advancements need to be made to enable clinical utility, HMR demonstrates significant potential as the next frontier of intraoperative visualization.

  View details for DOI 10.1177/1553350620984339

  View details for Web of Science ID 000621140400001

  View details for PubMedID 33382008

  View details for PubMedCentralID PMC8243385

• Aventricular hemispherotomy: technical note JOURNAL OF NEUROSURGERY-PEDIATRICS Brimley, C., Buch, V. P., Pisapia, J. M., Kennedy, B. C. 2020; 26 (6): 642-647

  Abstract

  Hemispheric disconnection in the form of hemispherectomy or hemispherotomy is the most effective way of treating intractable hemispheric epilepsy. Anatomical hemispherectomy approaches have largely been abandoned in most cases due to a higher risk of superficial hemosiderosis, intraoperative blood loss, hydrocephalus, prolonged hospital stay, and mortality compared to the variety of tissue-sparing hemispherotomy techniques. Disconnective hemispherotomy approaches utilize the lateral ventricle as a key component of the surgical corridor. Without a lateral ventricle, disconnective surgery becomes significantly challenging, typically leading to a hemispherectomy. The authors present the case of a patient with severe hemispheric dysplasia without a lateral ventricle on the pathologic side and detail a novel surgical technique for a prone, occipital interhemispheric, tissue-sparing, purely disconnective aventricular hemispherotomy with an excellent surgical outcome.

  View details for DOI 10.3171/2020.5.PEDS20247

  View details for Web of Science ID 000596398300006

  View details for PubMedID 32858506

• Policies Restricting Overlapping Surgeries Negatively Impact Access to Care, Clinical Efficiency and Hospital Revenue: A Forecasting Model for Surgical Scheduling. Annals of surgery Brandon, C., Ghenbot, Y., Buch, V., Contreras-Hernandez, E., Tooker, J., Dimentberg, R., Richardson, A. G., Lucas, T. H. 2020

  Abstract

  To model the financial impact of policies governing the scheduling of overlapping surgeries, and to identify optimal solutions that maximize operating efficiency that satisfy the fiduciary duty to patients.Hospitals depend on procedural revenue to maintain financial health as the recent pandemic has revealed. Proposed policies governing the scheduling of overlapping surgeries may dramatically impact hospital revenue. To date, the potential financial impact has not been modeled.A linear forecasting model based on a logic matrix decision tree enabled an analysis of surgeon productivity annualized over a fiscal year. The model applies procedural and operational variables to policy constraints limiting surgical scheduling. Model outputs included case and financial metrics modeled over 1000-surgeon-year simulations. Case metrics included annual case volume, case mix, operating room (OR) utilization, surgeon utilization, idle time and staff overtime hours. Financial outputs included annual revenue, expenses and contribution margin.The model was validated against surgical data. Case and financial metrics decreased as a function of increasingly restrictive scheduling scenarios, with the greatest contribution margin loses ($1,650,000 per surgeon-year) realized with the introduction of policies mandating that a second patient could not enter the OR until the critical portion of the first surgery was completed. We identify an optimal scheduling scenario that maximizes surgeon efficiency, minimizes OR idle time and revenue loses, and satisfies ethical obligations to patients.Hospitals may expect significant financial loses with the introduction of policies restricting OR scheduling. We identify an optimal solution that maximizes efficiency while satisfying ethical duty to patients. This forecast is immediately relevant to any hospital system that depends upon procedural revenue.

  View details for DOI 10.1097/SLA.0000000000004469

  View details for PubMedID 33086323

• Focused Ultrasound Thalamotomy with Dentato-Rubro-Thalamic Tractography in Patients with Spinal Cord Stimulators and Cardiac Pacemakers STEREOTACTIC AND FUNCTIONAL NEUROSURGERY Buch, V. P., McShane, B. J., Beatson, N., Yang, A., Blanke, A., Tilden, D., Korn, M., Chaibainou, H., Ramayya, A., Wombacher, K., Maier, S., Marashlian, T., Wolf, R., Baltuch, G. H. 2020; 98 (4): 263-269

  Abstract

  Magnetic resonance image-guided high-intensity focused ultrasound (MRgFUS)-based thermal ablation of the ventral intermediate nucleus of the thalamus (VIM) is a minimally invasive treatment modality for essential tremor (ET). Dentato-rubro-thalamic tractography (DRTT) is becoming increasingly popular for direct targeting of the presumed VIM ablation focus. It is currently unclear if patients with implanted pulse generators (IPGs) can safely undergo MRgFUS ablation and reliably acquire DRTT suitable for direct targeting. We present an 80-year-old male with a spinal cord stimulator (SCS) and an 88-year-old male with a cardiac pacemaker who both underwent MRgFUS for medically refractory ET. Clinical outcomes were measured using the Clinical Rating Scale for Tremor (CRST). DRTT was successfully created and imaging parameter adjustments did not result in any delay in procedural time in either case. In the first case, 7 therapeutic sonications were delivered. The patient improved immediately and durably with a 90% CRST-disability improvement at 6-week follow-up. In our second case, 6 therapeutic sonications were delivered with durable, 75% CRST-disability improvement at 6 weeks. These are the first cases of MRgFUS thalamotomy in patients with IPGs. DRTT targeting and MRgFUS-based thermal ablation can be safely performed in these patients using a 1.5-T MRI.

  View details for DOI 10.1159/000507031

  View details for Web of Science ID 000605966100006

  View details for PubMedID 32403106

• Detailed Analysis of Hydrocephalus and Hindbrain Herniation After Prenatal and Postnatal Myelomeningocele Closure: Report From a Single Institution NEUROSURGERY Flanders, T. M., Heuer, G. G., Madsen, P. J., Buch, V. P., Mackell, C. M., Alexander, E. E., Moldenhauer, J. S., Zarnow, D. M., Flake, A. W., Adzick, N. 2020; 86 (5): 637-645

  Abstract

  The Management of Myelomeningocele Study (MOMS) demonstrated that fetal myelomeningocele (fMMC) closure results in improved hydrocephalus and hindbrain herniation when compared to postnatal closure.To report on the outcomes of a single institution's experience in the post-MOMS era, with regard to hydrocephalus absence and hindbrain herniation resolution.A single-center retrospective study of a subset of post-MOMS patients who underwent fetal/postnatal myelomeningocele closure was performed. Primary outcomes included cerebrospinal fluid (CSF) diversion status and hindbrain herniation resolution. Families were contacted via telephone for outcome information if care was transitioned to outside institutions. Univariate/multivariable analyses were performed using several prenatal and postnatal variables.From January 2011 to May 2016, data were reviewed from families of 62 postnatal and 119 fMMC closure patients. In the postnatal group, 80.6% required CSF diversion compared to 38.7% fetal cases (P < .01). Hindbrain herniation resolution occurred in 81.5% fetal repairs compared to 32.6% postnatal (P < .01). In the fetal group, fetal/premature neonatal demise occurred in 6/119 (5.0%) patients. There was a 42.0% decrease (95% CI -55.2 to -28.8) and 48.9% increase (95% CI 33.7 to 64.1) in risk difference for CSF diversion and hindbrain herniation resolution, respectively, in the fetal group. On univariate analysis for both groups, prenatal atrial diameter, frontal-occipital horn ratio, and hindbrain herniation resolution were significantly associated with the absence of clinical hydrocephalus. The treatment of hydrocephalus was significantly delayed in the fetal group compared to the postnatal group (10 mo vs 13.8 d).This study demonstrates the benefits of fMMC closure with regard to CSF dynamics.

  View details for DOI 10.1093/neuros/nyz302

  View details for Web of Science ID 000537429900028

  View details for PubMedID 31432079

• Thalamic Deep Brain Stimulation for Essential Tremor: Relation of the Dentatorubrothalamic Tract with Stimulation Parameters WORLD NEUROSURGERY Yang, A., Buch, V. P., Heman-Ackah, S. M., Ramayya, A. G., Hitti, F. L., Beatson, N., Chaibainou, H., Yates, M., Wang, S., Verma, R., Wolf, R. L., Baltuch, G. H. 2020; 137: E89-E97

  Abstract

  In deep brain stimulation (DBS) for essential tremor, the primary target ventrointermedius (VIM) nucleus cannot be clearly visualized with structural imaging. As such, there has been much interest in the dentatorubrothalamic tract (DRTT) for target localization, but evidence for the DRTT as a putative stimulation target in tremor suppression is lacking. We evaluated proximity of the DRTT in relation to DBS stimulation parameters.This is a retrospective analysis of 26 consecutive patients who underwent DBS with microelectrode recordings (46 leads). Fiber tracking was performed with a published deterministic technique. Clinically optimized stimulation parameters were obtained in all patients at the time of most recent follow-up (6.2 months). Volume of tissue activated (VTA) around contacts was calculated from a published model.Tremor severity was reduced in all treated hemispheres, with 70% improvement in the treated hand score of the Clinical Rating Scale for Tremor. At the level of the active contact (2.9 ± 2.0 mm superior to the commissural plane), the center of the DRTT was lateral to the contacts (5.1 ± 2.1 mm). The nearest fibers of the DRTT were 2.4 ± 1.7 mm from the contacts, whereas the radius of the VTA was 2.9 ± 0.7 mm. The VTA overlapped with the DRTT in 77% of active contacts. The distance from active contact to the DRTT was positively correlated with stimulation voltage requirements (Kendall τ = 0.33, P = 0.006), whereas distance to the atlas-based VIM coordinates was not.Active contacts in proximity to the DRTT had lower voltage requirements. Data from a large cohort provide support for the DRTT as an effective stimulation target for tremor control.

  View details for Web of Science ID 000532762900003

  View details for PubMedID 31954907

  View details for PubMedCentralID PMC7584387

• Near-Infrared Fluorescence with Second-Window Indocyanine Green as an Adjunct to Localize the Pituitary Stalk During Skull Base Surgery WORLD NEUROSURGERY Cho, S. S., Buch, V. P., Teng, C. W., De Ravin, E., Lee, J. K. 2020; 136: 326

  Abstract

  A potential application of near-infrared (NIR) fluorescence imaging using second-window indocyanine green (SWIG) is demonstrated. We hypothesized that because the pituitary lacks a blood-brain barrier, we might visualize the pituitary stalk using SWIG. A 52-year-old, right-handed man presented to our clinic for evaluation of progressive loss of vision. Physical examination was significant for loss of right peripheral vision and near-complete loss of left field vision. Prolactin was high-normal at 16.2 mg/dL. Brain magnetic resonance imaging demonstrated a 36-mm sellar mass extending superiorly and laterally crossing the intracranial left internal carotid artery, consistent with a nonfunctional pituitary macroadenoma. We elected to pursue left pterional craniotomy for resection. The patient was eligible for our SWIG clinical trial and consented to the study. SWIG is a novel, investigational technique using Food and Drug Administration-approved indocyanine green to enhance visualization of neoplastic tissue intraoperatively.1-7 The patient received 2.5 mg/kg of indocyanine green intravenously approximately 24 hours preoperatively. Intraoperatively, under white-light microscopy, the tumor was easily identified and distinguished from the optic nerves and internal carotid artery. After debulking of the gross tumor, NIR visualization using a laser-equipped endoscope8 demonstrated strong NIR fluorescence in the pituitary stalk. Despite the distorted anatomy, this technique enabled us to confidently identify and preserve the pituitary stalk. Postoperatively, the patient had persistently high urine output that normalized in 24 hours without desmopressin (sodium 139-140 mmol/L); after uneventful recovery, he was discharged with mild improvement in visual function. This case demonstrated a potential use of our SWIG protocol. As the stalk demonstrates strong NIR fluorescence after high-dose indocyanine green administration, surgeons may be able to better localize and preserve the stalk even in complex skull base tumor cases where the anatomy may be significantly distorted.

  View details for DOI 10.1016/j.wneu.2020.01.135

  View details for Web of Science ID 000520838600135

  View details for PubMedID 31996340

• F-18-Fluciclovine PET to distinguish treatment-related effects from disease progression in recurrent glioblastoma: PET fusion with MRI guides neurosurgical sampling NEURO-ONCOLOGY PRACTICE Henderson, F., Brem, S., O'Rourke, D. M., Nasrallah, M., Buch, V. P., Young, A. J., Doot, R. K., Pantel, A., Desai, A., Bagley, S. J., Nabavizadeh, S. 2020; 7 (2): 152-157

  Abstract

  Differentiation of true tumor progression from treatment-related effects remains a major unmet need in caring for patients with glioblastoma. Here, we report how the intraoperative combination of MRI with18F-fluciclovine PET guided surgical sampling in 2 patients with recurrent glioblastoma.18F-Fluciclovine PET is FDA approved for use in prostate cancer and carries an orphan drug designation in glioma. To investigate its utility in recurrent glioblastoma, we fused PET and MRI images using 2 different surgical navigation systems and performed targeted stereotactic biopsies from the areas of high ("hot") and low ("cold") radiotracer uptake. Concordant histopathologic and imaging findings suggest that a combined18F-fluciclovine PET-MRI-guided approach can guide neurosurgical resection of viable recurrent glioblastoma in the background of treatment-related effects, which can otherwise look similar on MRI.

  View details for DOI 10.1093/nop/npz068

  View details for Web of Science ID 000536505600004

  View details for PubMedID 32206320

  View details for PubMedCentralID PMC7081387

• How technology is driving the landscape of epilepsy surgery EPILEPSIA Dorfer, C., Rydenhag, B., Baltuch, G., Buch, V., Blount, J., Bollo, R., Gerrard, J., Nilsson, D., Roessler, K., Rutka, J., Sharan, A., Spencer, D., Cukiert, A. 2020; 61 (5): 841-855

  Abstract

  This article emphasizes the role of the technological progress in changing the landscape of epilepsy surgery and provides a critical appraisal of robotic applications, laser interstitial thermal therapy, intraoperative imaging, wireless recording, new neuromodulation techniques, and high-intensity focused ultrasound. Specifically, (a) it relativizes the current hype in using robots for stereo-electroencephalography (SEEG) to increase the accuracy of depth electrode placement and save operating time; (b) discusses the drawback of laser interstitial thermal therapy (LITT) when it comes to the need for adequate histopathologic specimen and the fact that the concept of stereotactic disconnection is not new; (c) addresses the ratio between the benefits and expenditure of using intraoperative magnetic resonance imaging (MRI), that is, the high technical and personnel expertise needed that might restrict its use to centers with a high case load, including those unrelated to epilepsy; (d) soberly reviews the advantages, disadvantages, and future potentials of neuromodulation techniques with special emphasis on the differences between closed and open-loop systems; and (e) provides a critical outlook on the clinical implications of focused ultrasound, wireless recording, and multipurpose electrodes that are already on the horizon. This outlook shows that although current ultrasonic systems do have some limitations in delivering the acoustic energy, further advance of this technique may lead to novel treatment paradigms. Furthermore, it highlights that new data streams from multipurpose electrodes and wireless transmission of intracranial recordings will become available soon once some critical developments will be achieved such as electrode fidelity, data processing and storage, heat conduction as well as rechargeable technology. A better understanding of modern epilepsy surgery will help to demystify epilepsy surgery for the patients and the treating physicians and thereby reduce the surgical treatment gap.

  View details for DOI 10.1111/epi.16489

  View details for Web of Science ID 000522059400001

  View details for PubMedID 32227349

  View details for PubMedCentralID PMC7317716

• Second Window Indocyanine Green (SWIG) Near Infrared Fluorescent Transventricular Biopsy of Pineal Tumor WORLD NEUROSURGERY Cho, A., Cho, S. S., Buch, V. P., Buch, L. Y., Lee, J. K. 2020; 134: 196-200

  Abstract

  Second Window Indocyanine Green (SWIG) is a novel technique for real-time, intraoperative tumor visualization using a high-dose infusion of indocyanine green (ICG) 24 hours before surgery. Due to pathologic diversity found in the pineal region, tissue diagnosis in patients with pineal region mass is essential to optimize further clinical management.We present the case of a 75-year-old woman with known pineal region mass for 18 years, who presented with progressive classic signs and symptoms of obstructive hydrocephalus over the past 6 months. Preoperative imaging confirmed a contrast-enhancing pineal region tumor, which appeared to be obstructing the aqueduct of Sylvius, causing proximal obstructive hydrocephalus. We delivered 5 mg/kg of ICG intravenously 24 hours before the surgery. The patient underwent an endoscopic third ventriculostomy and a biopsy of the pineal lesion. The tumor demonstrated clear near-infrared fluorescence, which was distinct from surrounding third ventricle floor and ependyma. The signal-to-background ratio was 2.9. The final pathology report revealed a World Health Organization grade I pineocytoma.We report on a novel application of near-infrared fluorescence for tumor identification of pineal region tumors, using the "SWIG technique."

  View details for DOI 10.1016/j.wneu.2019.10.113

  View details for Web of Science ID 000512878200170

  View details for PubMedID 31669685

• Refocusing neurosurgical resident education amidst the COVID-19 crisis: A mental imagery-based transfer learning approach for virtual teaching of operative fundamentals. Sinha, S., Howard, S. D., Buch, V. P. Annals of Surgical Education. 2020 3
• Endoscopic endonasal resection versus open surgery for pediatric craniopharyngioma: comparison of outcomes and complications JOURNAL OF NEUROSURGERY-PEDIATRICS Madsen, P. J., Buch, V. P., Douglas, J. E., Parasher, A. K., Lerner, D. K., Alexander, E., Workman, A. D., Palmer, J. N., Lang, S., Kennedy, B. C., Vossough, A., Adappa, N. D., Storm, P. B. 2019; 24 (3): 236-245

  Abstract

  Craniopharyngioma represents up to 10% of pediatric brain tumors. Although these lesions are benign, attempts at gross-total resection (GTR) can lead to serious complications. More conservative approaches have emerged but require adjuvant radiation. Endoscopic endonasal surgery (EES) aimed at GTR has the potential to result in fewer complications, but there has been limited comparison to open surgery. The authors performed a review of these two approaches within their institution to elucidate potential benefits and complication differences.The authors performed a retrospective review of pediatric patients undergoing resection of craniopharyngioma at their institution between 2001 and 2017. Volumetric analysis of tumor size and postoperative ischemic injury was performed. Charts were reviewed for a number of outcome measures.A total of 43 patients with an average age of 8.2 years were identified. Open surgery was the initial intervention in 15 and EES in 28. EES was performed in patients 3-17 years of age. EES has been the only approach used since 2011. In the entire cohort, GTR was more common in the EES group (85.7% vs 53.3%, p = 0.03). Recurrence rate (40% vs 14.2%, p = 0.13) and need for adjuvant radiation (20.0% vs 10.7%, p = 0.71) were higher in the open surgical group, although not statistically significant. Pseudoaneurysm development was only observed in the open surgical group. Volumetric imaging analysis showed a trend toward larger preoperative tumor volumes in the open surgical group, so a matched cohort analysis was performed with the largest tumors from the EES group. This revealed no difference in residual tumor volume (p = 0.28), but the volume of postoperative ischemia was still significantly larger in the open group (p = 0.004). Postoperative weight gain was more common in the open surgical group, a statistically significant finding in the complete patient group that trended toward significance in the matched cohort groups. Body mass index at follow-up correlated with volume of ischemic injury in regression analysis of the complete patient cohort (p = 0.05).EES was associated with similar, if not better, extent of resection and significantly less ischemic injury than open surgery. Pseudoaneurysms were only seen in the open surgical group. Weight gain was also less prevalent in the EES cohort and appears be correlated with extent of ischemic injury at time of surgery.

  View details for DOI 10.3171/2019.4.PEDS18612

  View details for Web of Science ID 000484053700003

  View details for PubMedID 31174192

• Stereoelectroencephalography in Pediatric Epilepsy Surgery JOURNAL OF KOREAN NEUROSURGICAL SOCIETY Tomlinson, S. B., Buch, V. P., Armstrong, D., Kennedy, B. C. 2019; 62 (3): 302-312

  Abstract

  Stereoelectroencephalography (SEEG) is an invasive technique used during the surgical management of medically refractory epilepsy. The utility of SEEG rests in its ability to survey the three-dimensional organization of the epileptogenic zone as well as nearby eloquent cortices. Once concentrated to specialized centers in Europe and Canada, the SEEG methodology has gained worldwide popularity due to its favorable morbidity profile, superior coverage of deep structures, and ability to perform multilobar explorations without the need for craniotomy. This rapid shift in practice represents both a challenge and an opportunity for pediatric neurosurgeons familiar with the subdural grid approach. The purpose of this review is to discuss the indications, technique, and safety of long-term SEEG monitoring in children. In addition to reviewing the conceptual and technical points of the diagnostic evaluation, attention will also be given to SEEG-based interventions (e.g., radiofrequency thermo-coagulation).

  View details for DOI 10.3340/jkns.2019.0015

  View details for Web of Science ID 000467678700006

  View details for PubMedID 31085956

  View details for PubMedCentralID PMC6514312

• An estimation of global volume of surgically treatable epilepsy based on a systematic review and meta-analysis of epilepsy JOURNAL OF NEUROSURGERY Vaughan, K. A., Ramos, C., Buch, V. P., Mekary, R. A., Amundson, J. R., Shah, M., Rattani, A., Dewan, M. C., Park, K. B. 2019; 130 (4): 1127-1141

  Abstract

  OBJECTIVEEpilepsy is one of the most common neurological disorders, yet its global surgical burden has yet to be characterized. The authors sought to compile the most current epidemiological data to quantify global prevalence and incidence, and estimate global surgically treatable epilepsy. Understanding regional and global epilepsy trends and potential surgical volume is crucial for future policy efforts and resource allocation.METHODSThe authors performed a systematic literature review and meta-analysis to determine the global incidence, lifetime prevalence, and active prevalence of epilepsy; to estimate surgically treatable epilepsy volume; and to evaluate regional trends by WHO regions and World Bank income levels. Data were extracted from all population-based studies with prespecified methodological quality across all countries and demographics, performed between 1990 and 2016 and indexed on PubMed, EMBASE, and Cochrane. The current and annual new case volumes for surgically treatable epilepsy were derived from global epilepsy prevalence and incidence.RESULTSThis systematic review yielded 167 articles, across all WHO regions and income levels. Meta-analysis showed a raw global prevalence of lifetime epilepsy of 1099 per 100,000 people, whereas active epilepsy prevalence is slightly lower at 690 per 100,000 people. Global incidence was found to be 62 cases per 100,000 person-years. The meta-analysis predicted 4.6 million new cases of epilepsy annually worldwide, a prevalence of 51.7 million active epilepsy cases, and 82.3 million people with any lifetime epilepsy diagnosis. Differences across WHO regions and country incomes were significant. The authors estimate that currently 10.1 million patients with epilepsy may be surgical treatment candidates, and 1.4 million new surgically treatable epilepsy cases arise annually. The highest prevalences are found in Africa and Latin America, although the highest incidences are reported in the Middle East and Latin America. These regions are primarily low- and middle-income countries; as expected, the highest disease burden falls disproportionately on regions with the fewest healthcare resources.CONCLUSIONSUnderstanding of the global epilepsy burden has evolved as more regions have been studied. This up-to-date worldwide analysis provides the first estimate of surgical epilepsy volume and an updated comprehensive overview of current epidemiological trends. The disproportionate burden of epilepsy on low- and middle-income countries will require targeted diagnostic and treatment efforts to reduce the global disparities in care and cost. Quantifying global epilepsy provides the first step toward restructuring the allocation of healthcare resources as part of global healthcare system strengthening.

  View details for DOI 10.3171/2018.3.JNS171722

  View details for Web of Science ID 000462866700009

  View details for PubMedID 30215556

• Factors Predicting Ventriculostomy Revision at a Large Academic Medical Center WORLD NEUROSURGERY Ramayya, A. G., Glauser, G., Mcshane, B., Branche, M., Sinha, S., Kvint, S., Buch, V., Abdullah, K. G., Kung, D., Chen, H., Malhotra, N. R., Ozturk, A. 2019; 123: E509-E514

  Abstract

  Freehand bedside ventriculostomy placement can result in catheter malfunction requiring a revision procedure and cause significant patient morbidity. We performed a single-center retrospective review to assess factors related to this complication.Using an administrative database and chart review, we identified 101 first-time external ventricular drain placements performed at the bedside. We collected data regarding demographics, medical comorbidities, complications, and catheter tip location. We performed univariate and multivariate statistical analyses using MATLAB. We corrected for multiple comparisons using the false discovery rate (FDR) procedure.Multivariate regression analyses revealed that revision procedures were more likely to occur after drain blockage (odds ratio [OR] 17.9) and hemorrhage (OR 10.3, FDR-corrected P values < 0.01, 0.05, respectively). Drain blockage was less frequent after placement in an "optimal location" (ipsilateral ventricle or near foramen of Monroe; OR 0.09, P = 0.009, FDR-corrected P < 0.03) but was more likely to occur after placement in third ventricle (post-hoc P values < 0.015). Primary diagnoses included subarachnoid hemorrhage (n = 30, 29.7%), intraparenchymal hemorrhage with intraventricular extravasation (n = 24, 23.7%), tumor (n = 20, 19.8%), and trauma (n = 17, 16.8%). Most common complications included drain blockage (n = 12, 11.8%) and hemorrhage (n = 8, 7.9%). In total, 16 patients underwent at least 1 revision procedure (15.8%).Bedside external ventricular drain placement is associated with a 15% rate of revision, that typically occurred after drain blockage and postprocedure hemorrhage. Optimal placement within the ipsilateral frontal horn or foramen of Monroe was associated with a reduced rate of drain blockage.

  View details for DOI 10.1016/j.wneu.2018.11.196

  View details for Web of Science ID 000462958400059

  View details for PubMedID 30503293

• Novel Inter-Trial Resting State Network Analysis can Reliably Predict Learning and Performance of a Cognitive Reaction Time Task Buch, V. P., Cameron, B., Archer, R., Stiso, J., Ramayya, A., Yang, A., Richardson, A., Bassett, D., Lucas, T. JOURNAL OF NEUROSURGERY. 2019
• Increased dynamic modularity of the fronto-temporo-limbic network precedes enhanced task performance Journal of Neurosurgery Buch, V., Brandon, C., Khambhati, A., Richardson, A., Bassett, D., Lucas, T. 2018
• Rotational vertebrobasilar insufficiency due to compression of a persistent first intersegmental vertebral artery variant: case report JOURNAL OF NEUROSURGERY-SPINE Buch, V. P., Madsen, P. J., Vaughan, K. A., Koch, P. F., Kung, D. K., Ozturk, A. K. 2017; 26 (2): 199-202

  Abstract

  Rotational vertebrobasilar insufficiency, or bow hunter's syndrome, is a rare cause of posterior circulation ischemia, which, following rotation of the head, results in episodic vertigo, dizziness, nystagmus, or syncope. While typically caused by dynamic occlusion of the vertebral artery in its V2 and V3 segments, the authors here describe a patient with dynamic occlusion of the vertebral artery secondary to a persistent first intersegmental artery, a rare variant course of the vertebral artery. In this case the vertebral artery coursed under rather than over the posterior arch of the C-1. This patient was also found to have incomplete development of the posterior arch of C-1, as is often seen with this variant. The patient underwent dynamic digital subtraction angiography, which demonstrated occlusion at the variant vertebral artery with head turning. He was then taken for decompression of the vertebral artery through removal of the incomplete arch of C-1 that was causing the dynamic compression. After surgery the patient had a complete resolution of symptoms. In this report, the authors present the details of this case, describe the anatomical variants involved, and provide a discussion regarding the need for atlantoaxial fusion in these patients.

  View details for DOI 10.3171/2016.7.SPINE163

  View details for Web of Science ID 000393088900010

  View details for PubMedID 27716015

• Resident simulation training in endoscopic endonasal surgery utilizing haptic feedback technology JOURNAL OF CLINICAL NEUROSCIENCE Thawani, J. P., Ramayya, A. G., Abdullah, K. G., Hudgins, E., Vaughan, K., Piazza, M., Madsen, P. J., Buch, V., Grady, M. 2016; 34: 112-116

  Abstract

  Simulated practice may improve resident performance in endoscopic endonasal surgery. Using the NeuroTouch haptic simulation platform, we evaluated resident performance and assessed the effect of simulation training on performance in the operating room. First- (N=3) and second- (N=3) year residents were assessed using six measures of proficiency. Using a visual analog scale, the senior author scored subjects. After the first session, subjects with lower scores were provided with simulation training. A second simulation served as a task-learning control. Residents were evaluated in the operating room over six months by the senior author-who was blinded to the trained/untrained identities-using the same parameters. A nonparametric bootstrap testing method was used for the analysis (Matlab v. 2014a). Simulation training was associated with an increase in performance scores in the operating room averaged over all measures (p=0.0045). This is the first study to evaluate the training utility of an endoscopic endonasal surgical task using a virtual reality haptic simulator. The data suggest that haptic simulation training in endoscopic neurosurgery may contribute to improvements in operative performance. Limitations include a small number of subjects and adjudication bias-although the trained/untrained identity of subjects was blinded. Further study using the proposed methods may better describe the relationship between simulated training and operative performance in endoscopic Neurosurgery.

  View details for DOI 10.1016/j.jocn.2016.05.036

  View details for Web of Science ID 000389093300023

  View details for PubMedID 27473019

• Lumbar decompression for dorsiflexion palsy JOURNAL OF THE NEUROLOGICAL SCIENCES Buch, V. P., Ozturk, A. K. 2016; 362: 64-65

  View details for DOI 10.1016/j.jns.2015.12.036

  View details for Web of Science ID 000372558400011

  View details for PubMedID 26944119

• 210 Human Sensorimotor Electrocorticography: Spectral Dynamics and Network Connectivity During a Simple Motor Task Neurosurgery Buch, V. P., Burke, J. F., Ramayya, A. G., Brandon, C., Hudgins, E., Richardson, A., Lucas, T. H. 2016; 63 (CN_suppl_1)

  View details for DOI 10.1227/01.neu.0000489779.53428.e3

• Varicella zoster-induced magnetic resonance imaging abnormalities of the trigeminal nucleus JOURNAL OF THE NEUROLOGICAL SCIENCES Douglas, J. E., Buch, V. P., Mamourian, A. C. 2015; 359 (1-2): 57-58

  View details for DOI 10.1016/j.jns.2015.10.029

  View details for Web of Science ID 000367276200011

  View details for PubMedID 26671086