Neuromodulation with Ultrasound: Hypotheses on the Directionality of Effects and a Community Resource.

Low-intensity Transcranial Ultrasound Stimulation (TUS) is a promising non-invasive technique for deep-brain stimulation and focal neuromodulation. Research with animal models and computational modelling has raised the possibility that TUS can be biased towards enhancing or suppressing neural function. Here, we first conduct a systematic review of human TUS studies for perturbing neural function and alleviating brain disorders. We then collate a set of hypotheses on the directionality of TUS effects and conduct an initial meta-analysis on the human TUS study reported outcomes to date ( n = 32 studies, 37 experiments). We find that parameters such as the duty cycle show some predictability regarding whether the targeted area's function is likely to be enhanced or suppressed. Given that human TUS sample sizes are exponentially increasing, we recognize that results can stabilize or change as further studies are reported. Therefore, we conclude by establishing an Iowa-Newcastle (inTUS) resource for the systematic reporting of TUS parameters and outcomes to support further hypothesis testing for greater precision in brain stimulation and neuromodulation with TUS. Highlights: Systematic review of human TUS studies for enhancing or suppressing neural functionCollated set of hypotheses on using TUS to bias towards enhancement or suppressionMeta-analysis results identify parameters that may bias the directionality of effectsTUS resource established for systematic reporting of TUS parameters and outcomes.

Survival and neurological outcomes following management of intramedullary spinal metastasis patients: a case series with comprehensive review of the literature.

Intramedullary spinal cord metastasis (ISCM), though rare, represents a potentially debilitating manifestation of systemic cancer. With emerging advances in cancer care, ISCMs are increasingly being encountered in clinical practice. Herein, we describe one of the larger retrospective single institutional case series on ISCMs, analyze survival and treatment outcomes, and review the literature. All surgically evaluated ISCMs at our institution between 2005 and 2023 were retrospectively reviewed. Demographics, tumor features, treatment, and clinical outcome characteristics were collected. Neurological function was quantified via the Frankel grade and the McCormick score (MCS). The pre- and post-operative Karnofsky performance scores (KPS) were used to assess functional status. Descriptive statistics, univariate analysis, log-rank test, and the Kaplan-Meier survival analysis were performed. A total of 9 patients were included (median age 67 years (range, 26-71); 6 were male). Thoracic and cervical spinal segments were most affected (4 patients each). Six patients (75%) underwent surgical management (1 biopsy and 5 resections), and 3 cases underwent chemoradiation only. Post-operatively, 2 patients had an improvement in their neurological exam with one patient becoming ambulatory after surgery; three patients maintained their neurological exam, and 1 had a decline. There was no statistically significant difference in the pre- and post-operative MCS and median KPS scores in surgically treated patients. Median OS after ISCM diagnosis was 7 months. Absence of brain metastasis, tumor histology (renal and melanoma), cervical/thoracic location, and post-op KPS ≥ 70 showed a trend toward improved overall survival. The incidence of ISCM is increasing, and earlier diagnosis and treatment are considered key for the preservation of neurological function. When patient characteristics are favorable, surgical resection of ISCM can be considered in patients with rapidly progressive neurological deficits. Surgical treatment was not associated with an improvement in overall survival in patients with ISCMs.

Cervical, Intradural Extramedullary Solitary Fibrous Tumor of the Spinal Cord: A Case Report and Review of the Literature.

Solitary fibrous tumors (SFTs) are rare, spindle cell neoplasms of the mesenchymal origin. Lesions localized to the spine are exceptionally uncommon, only described in the literature in case reports and small case series. While these lesions are typically benign, there are a few reports in which they recur or present as malignancies. The patient presented in the case herein was a 72-year-old male, who presented with a 1-year history of lower extremity weakness, pain, and numbness and was found to have a cervical, intradural extramedullary tumor. In addition to the case report, the authors perform a thorough review of all previously published cases of spinal SFT.

Methods and Devices for Posterior Ventriculoperitoneal Shunt Placement Surgery: 25 Years of Iterative Refinement.

BACKGROUND: The posterior ventriculoperitoneal shunt (VPS) placement procedure is technically efficient and cosmetically appealing. The main limitations of the posterior approach relate to the technical challenges associated with accurately placing the ventricular catheter. In this report, we describe methods and simple devices used for posterior VPS surgery that have evolved over a >25-year period to enhance catheter placement accuracy and reduce complication rates. OBJECTIVE: We describe the combination of methods and customized devices used at a single institution to perform posterior VPS surgery. Results are presented for the most recent 11-year epoch, along with a description of sources of technical errors and plans for further methodologic refinements. MATERIALS AND METHODS: The medical records and imaging studies of 468 patients undergoing posterior VPS, from 2007 to 2018 were reviewed. Ventricular catheter placement accuracy data were collected and complications were identified and recorded. RESULTS: Optimal ventricular catheter placement was achieved in 98.29%. Of the remaining 1.71%, one half (0.85%) required acute revision surgery. Four patients (0.85%) developed new neurologic deficits following surgery; 2 were related to intraparenchymal hemorrhages and 2 (0.43%) as a result of a misplaced catheter. The deficits resulting from poor catheter placement were transient. The complication rates due to causes other than catheter placement accuracy compared favorably with those reported previously in the literature. CONCLUSIONS: Using the methods and devices described in this series, posterior VPS operations can be performed safely with a high degree of ventricular catheter placement accuracy.

Dural Arteriovenous Fistula Associated With a Vestibular Tumor: An Unusual Case and Review of the Literature.

Intracranial dural arteriovenous fistulae (DAVF) are rare vascular malformations. They are generally considered to be acquired lesions, often attributed to dural sinus thrombosis and intracranial venous hypertension. The authors encountered a case of DAVF associated with an octreotide-positive vestibular schwannoma. A 46-year-old female had symptoms of right ear congestion accompanied by pulsatile tinnitus and mild hearing loss. Magnetic resonance imaging (MRI) identified a lobulated mass centered at the cerebellopontine angle. Preoperatively, on cerebral angiography, there was an incidental discovery of a DAVF in the right posterior fossa. The decision was made to proceed with resection of the tumor in a staged fashion. Her latest follow-up MRI showed no evidence of recurrent tumor. This is the second reported case of DAVF associated with an intracranial schwannoma. Findings are discussed along with a thorough review of the literature. This case, combined with the data from the literature review, led us to believe that tumor-related angiogenesis might contribute to DAVF formation.

Duplication of the vertebral artery: A series of four cases.

INTRODUCTION: Duplication of the vertebral artery (VA) is a rare vascular variant, with less than 50 reported cases in the literature. CASE SERIES: We present four cases of VA duplication and discuss the imaging findings, which highlight the rarely seen VA duplication. DISCUSSION: VA duplication is generally considered to be an incidental finding. The VA is formed from the fusion of the longitudinal anastomoses that link the cervical intersegmental arteries, during the 32-40-day stage. The duplication of the VA is a clinically relevant finding for planning of head and neck surgery and neuro-interventional procedures.

Complete spontaneous regression of cerebral arteriovenous malformation: a case report and review of the literature.

Spontaneous regression of an arteriovenous malformation (AVM) is the phenomenon of partial or complete obliteration of the vascular anomaly without any therapeutic intervention. Complete spontaneous regression is a rare event with limited previously reported cases in the literature. We present a new case of complete spontaneous regression of a right frontal AVM and report findings from the imaging studies. Furthermore, we present the findings of a detailed literature review and discuss hypotheses regarding the pathophysiology of this rare occurrence.