Intracranial ventricular shunts.

Permanent shunt diversion of cerebrospinal fluid away from the central nervous system is a widely recognized neurosurgical procedure. Still, patients with ventricular shunts are at substantial risk of shunt dysfunction, which includes complications like mechanical shunt failure, abnormal shunt drainage and infection. Early detection of shunt dysfunction is essential to proper and timely treatment, and acute shunt dysfunction might require immediate intervention. This review summarizes current and potential strategies for investigation of shunt dysfunction.

Meningioma animal models: a systematic review and meta-analysis.

BACKGROUND: Animal models are widely used to study pathological processes and drug (side) effects in a controlled environment. There is a wide variety of methods available for establishing animal models depending on the research question. Commonly used methods in tumor research include xenografting cells (established/commercially available or primary patient-derived) or whole tumor pieces either orthotopically or heterotopically and the more recent genetically engineered models-each type with their own advantages and disadvantages. The current systematic review aimed to investigate the meningioma model types used, perform a meta-analysis on tumor take rate (TTR), and perform critical appraisal of the included studies. The study also aimed to assess reproducibility, reliability, means of validation and verification of models, alongside pros and cons and uses of the model types. METHODS: We searched Medline, Embase, and Web of Science for all in vivo meningioma models. The primary outcome was tumor take rate. Meta-analysis was performed on tumor take rate followed by subgroup analyses on the number of cells and duration of incubation. The validity of the tumor models was assessed qualitatively. We performed critical appraisal of the methodological quality and quality of reporting for all included studies. RESULTS: We included 114 unique records (78 using established cell line models (ECLM), 21 using primary patient-derived tumor models (PTM), 10 using genetically engineered models (GEM), and 11 using uncategorized models). TTRs for ECLM were 94% (95% CI 92-96) for orthotopic and 95% (93-96) for heterotopic. PTM showed lower TTRs [orthotopic 53% (33-72) and heterotopic 82% (73-89)] and finally GEM revealed a TTR of 34% (26-43). CONCLUSION: This systematic review shows high consistent TTRs in established cell line models and varying TTRs in primary patient-derived models and genetically engineered models. However, we identified several issues regarding the quality of reporting and the methodological approach that reduce the validity, transparency, and reproducibility of studies and suggest a high risk of publication bias. Finally, each tumor model type has specific roles in research based on their advantages (and disadvantages). SYSTEMATIC REVIEW REGISTRATION: PROSPERO-ID CRD42022308833.

Ventriculosinus shunt: a pilot study to investigate new technology to treat hydrocephalus and mimic physiological principles of cerebrospinal fluid drainage.

OBJECTIVE: Devices draining CSF to the intracranial venous sinus for the treatment of hydrocephalus have been tested in the past, and while clinically effective, have not shown efficacy in the long term. The majority of these devices become obstructed within 3 months due to endothelial overgrowth. In this study, the authors investigated a newly developed ventriculosinus (VS) shunt outlet device with the objective of showing it would remain patent for at least 6 months. METHODS: Twelve patients in need of shunting for hydrocephalus underwent an operation using the investigational device and were followed for 6 months to record patency of the shunt. RESULTS: In 10 patients, the shunt was patent at 6 months, with the outlet device remaining unobstructed. In the remaining 2 patients, one died just before reaching the 6-month endpoint, and in the other the outlet was misplaced during surgery and therefore ceased to function after 3 months. No occlusion of the internal jugular vein or thrombus formation was noted in any of the 12 cases. CONCLUSIONS: These findings indicate that the outlet device can remain patent and has the capability to mimic physiological drainage by diverting CSF to the intracranial sinus. Additional confirmation of its potential as part of a new VS shunt system and ultimately as a viable alternative for ventriculoperitoneal and ventriculoatrial shunting to reduce complication rates requires further clinical trials.

Retinal vessel dynamics analysis as a surrogate marker for raised intracranial pressure in patients with suspected idiopathic intracranial hypertension.

INTRODUCTION: Retinal vessel dynamics analysis has proven to be a viable, non-invasive surrogate marker for increased intracranial pressure. We aimed to test this method in patients with suspected idiopathic intracranial hypertension. METHODS: Patients with suspected idiopathic intracranial hypertension were prospectively enrolled for hand-held fundus-videography during diagnostic lumbar puncture. After extracting optic disc images, peripapillary arteriole-to-venule-ratios were measured using machine-learning algorithms with manual identification control. A general linear model was applied to arteriole-to-venule-ratios and corresponding lumbar opening pressures to estimate cerebrospinal fluid pressure. RESULTS: Twenty-five patients were included with a significant difference in arteriole-to-venule-ratio between patients with (n = 17) and without (n = 8) idiopathic intracranial hypertension (0.78 ± 0.10 vs 0.90 ± 0.08, p = 0.006). Arteriole-to-venule-ratio correlated inversely with lumbar opening pressure (slope regression estimate -0.0043 (95% CI -0.0073 to -0.0023), p = 0.002) and the association was stronger when lumbar opening pressure exceeded 15 mm Hg (20 cm H2O) (slope regression estimate -0.0080 (95% CI -0.0123 to -0.0039), p < 0.001). Estimated cerebrospinal fluid pressure predicted increased lumbar opening pressure >20 mm Hg (27 cm H2O) with 78% sensitivity and 92% specificity (AUC 0.81, p = 0.02). A stand-alone arteriole-to-venule-ratio measurement predicting lumbar opening pressure >20 mm Hg (27 cm H2O) was inferior with a 48% sensitivity and 92% specificity (AUC 0.73, p = 0.002). CONCLUSION: Retinal vessel dynamics analysis with the described model for estimating cerebrospinal fluid pressure is a promising non-invasive method with a high sensitivity and specificity for detecting elevated intracranial pressure at follow-up assessments of patients with confirmed idiopathic intracranial hypertension if initial lumbar opening pressure and arteriole-to-venule-ratio data are available.

Endonasal Endoscopic Approach for Minimally Invasive Orbital Decompression in Nonthyroid Proptosis-A Scoping Review.

OBJECTIVE: The endoscopic endonasal approach (EEA) was originally performed to treat thyroid orbitopathy and proptosis. Since then, this approach also has been used to treat other causes of proptosis. This review systematically identifies surgical outcome and complication rates in patients without thyroid proptosis who underwent endoscopic endonasal orbital decompression. METHODS: Databases were searched using the following search terms: orbital disease, surgical decompression, and endoscopic endonasal approach. Two independent reviewers screened all abstracts and titles for relevance and all articles passing this screen were subjected to full-text review. To assess risk of bias, we used ROBINS-I (Risk Of Bias in Non-randomized Studies-of Interventions). RESULTS: Eight studies with a total of 74 patients with nonthyroid proptosis were included. Pre- and postoperative eye examination was performed in all studies, but the extent of examination was varying. With a mean age of 35.7 years, most patients were adolescent, and most pathologies induced unilateral proptosis Complications to EEA for orbital decompression were transient diplopia (5 patients/6.8%), transient facial dysesthesia (2 patients/2.7%), ptosis (1 patient/1.4%), infarction (1 patient/1.4%), sinus obstruction (1 patient/1.4%), and enophtalmos (1 patient/1.4%). The authors reported successful reduction of proptosis in all but 2 patients (97.2%), and only 2 authors reported a need for secondary decompression. CONCLUSIONS: Medial orbital decompression using EEA is a feasible approach for orbital decompression in patients with nonthyroid proptosis. While being comparable in primary outcome to transorbital approaches, the EEA seems superior in terms of complication rates.

Magnetic Resonance Elastography in Intracranial Neoplasms: A Scoping Review.

BACKGROUND: Magnetic resonance elastography (MRE) allows noninvasive assessment of intracranial tumor mechanics and may thus be predictive of intraoperative conditions. Variations in the use of technical terms complicate reading of current literature, and there is need of a review using consolidated nomenclature. OBJECTIVES: We present an overview of current literature on MRE relating to human intracranial neoplasms using standardized nomenclature suggested by the MRE guidelines committee. We then discuss the implications of the findings, and suggest approaches for future research. METHOD: We performed a systematic literature search in PubMed, Embase, and Web of Science; the articles were screened for relevance and then subjected to full text review. Technical terms were consolidated. RESULTS: We identified 12 studies on MRE in patients with intracranial tumors, including meningiomas, glial tumors including glioblastomas, vestibular schwannomas, hemangiopericytoma, central nervous system lymphoma, pituitary macroadenomas, and brain metastases. The studies had varying objectives that included prediction of intraoperative consistency, histological separation, prediction of adhesiveness, and exploration of the mechanobiology of tumor invasiveness and malignancy. The technical terms were translated using standardized nomenclature. The literature was highly heterogeneous in terms of image acquisition techniques, post-processing, and study design and was generally limited by small and variable cohorts. CONCLUSIONS: MRE shows potential in predicting tumor consistency, adhesion, and mechanical homogeneity. Furthermore, MRE provides insight into malignant tumor behavior and its relation to tissue mechanics. MRE is still at a preclinical stage, but technical advances, improved understanding of soft tissue rheological impact, and larger samples are likely to enable future clinical introduction.

[Intracranial pressure and non-invasive pressure modalities].

As summarised in this review, the need for intracranial neuromonitoring is crucial in patients with elevated intracranial pressure (ICP) regardless of aetiology and geographic location. ICP monitoring still relies heavily on invasive measure modalities. Non-invasive pressure modalities would exclude some of the difficulties of the invasive: procedure-related complications and accessibility. However, non-invasive modalities have not been implemented due to lack of precision and varying results in clinical studies. New research in retinal vessel dynamics have shown promising results.

Mild trauma causing cervical fracture through transverse foramen leading to a vertebral arteriovenous fistula.

Vertebral arteriovenous fistula (vAVF) is an uncommon vascular disease defined as abnormal connections between the vertebral artery or its branches extracranially with nearby venous structures. This case report outlines the case of a man in his late 70s presenting with C1-C3 fractures after a mild trauma falling down a small staircase. CT angiogram (CTA) gave suspicion of vertebral artery dissection and pseudoaneurysm; however, digital subtraction angiography revealed a fracture-induced vAVF successfully treated endovascularly with coils. In conclusion, cervical fractures involving the transverse foramen regardless of trauma mechanism should result in a CTA. Endovascular treatment with ipsilateral vertebral artery closure is preferred due to its feasibility and safety.

[Orbital decompression in non-thyroid-associated diseases].

Hypoxia triggers hypoxia-inducible factor (HIF). Not only hypoxia triggers downstream HIF target genes for transcription, as intermittent hyperoxia also possesses similar capabilities, suggesting that fluctuations in oxygen availability may be equally important for inducing HIF transcription. This review describes some of the mechanisms, whereby intermittent hyperbaric hyperoxia may explain some of the observations during hyperbaric oxygen therapy such as enhanced wound healing, angiogenesis and tissue healing, and concludes that oxidative stress enhances certain antibiotics in infection control.

A new novel method for assessing intracranial pressure using non-invasive fundus images: a pilot study.

Arteriole and venule diameter ratio (A/V-ratio) can be measured using fundus photography. In this pilot study, we correlated changes in the intracranial pressure with the diameter of vessels of the retina. We investigated whether increased intracranial pressure (ICP) was reflected in a measurable and quantifiable distention of the venule diameter, leading to a decreased A/V-ratio. This was demonstrated by assessment of the A/V-ratio in patients already undergoing conventional ICP monitoring with a cerebral intraparenchymal pressure monitor. Our method shows a correlation between A/V ratio and ICP and suggests an easily obtainable and usable point-of-care (POC), non-invasive method to estimate the intracranial pressure without the necessity of mydriatic drugs. Furthermore, the sensitivity/specificity analysis with a cut-off of < 0.8015 A/V-ratio, showed a sensitivity of 94% [85-98%] and a specificity of 50% [34-66%] with a positive likelihood ratio of 9.0. This means that in a clinical setting there is a 94% chance of correctly identifying individuals with ICP ≥ 20 mmHg.

[MR-guided focused ultrasound for treatment of essential tremor].

Essential tremor can be a debilitating disease. In many cases, medical treatment is ineffective and/or holds significant side effects. Surgical treatment using deep brain stimulation is only possible in few and selected cases. The introduction of MR-guided focused ultrasound enables surgeons to make small and specific lesions in the thalamus with few side effects and limited risk for the patient. The effectiveness has been documented in several international studies and is summarised in this review.

[Intracranial meningiomas].

Meningiomas are the most frequent intracranial non-glial tumours. They are derived from arachnoid cap cells and are classified according to WHO histology-based classification. The epigenetic technique DNA methylation profiling has shown improved prognostic value in comparison to the current WHO classification. Total surgical tumour removal is still golden standard in meningioma treatment with radiation as a supplement for WHO high-grade patients and inoperable patients. Efficient medical alternatives to surgery are not yet available, but future research may provide new strategies to be explored.

Detection of membrane-bound and soluble antigens by magnetic levitation.

Magnetic levitation is a technique for measuring the density and the magnetic properties of objects suspended in a paramagnetic field. We describe a novel magnetic levitation-based method that can specifically detect cell membrane-bound and soluble antigens by measurable changes in levitation height that result from the formation of antibody-coated bead and antigen complex. We demonstrate our method's ability to sensitively detect an array of membrane-bound and soluble antigens found in blood, including T-cell antigen CD3, eosinophil antigen Siglec-8, red blood cell antigens CD35 and RhD, red blood cell-bound Epstein-Barr viral particles, and soluble IL-6, and validate the results by flow cytometry and immunofluorescence microscopy performed in parallel. Additionally, employing an inexpensive, single lens, manual focus, wifi-enabled camera, we extend the portability of our method for its potential use as a point-of-care diagnostic assay.