biodegradable-magnesium-stent-treatment-saccular-aneurysms-rat-model

Biodegradable Magnesium Stent Treatment of Saccular Aneurysms in a Rat Model - Introduction of the Surgical Technique

The steady progess in the armamentarium of techniques available for endovascular treatment of intracranial aneurysms requires affordable and reproducable ...

Kantonsspital Aarau

University Hospital and University of Bern

The accurate discrimination between tumor and normal tissue is crucial for determining how much to resect and therefore for the clinical outcome of patients with brain tumors. In recent years, guidance with 5-aminolevulinic acid (5-ALA)-induced intraoperative fluorescence has proven to be a useful surgical adjunct for gross-total resection of high-grade gliomas. The clinical utility of 5-ALA in resection of brain tumors other than glioblastomas has not yet been established. The authors assessed the frequency of positive 5-ALA fluorescence in a cohort of patients with primary brain tumors and metastases.

Use of fluorescence to guide resection or biopsy of primary brain tumors and brain metastases.

Pedicle screw placement is a very common procedure used to stabilize all three columns of the thoracic and lumbar spine. The purpose of this study is to evaluate the incidence of screw misplacement and related complications in patients who underwent fluoroscopy-guided transpedicular screw fixation at a neurosurgical teaching institution.

Accuracy of Pedicle Screw Placement in the Thoracic and Lumbosacral Spine Using a Conventional Intraoperative Fluoroscopy-Guided Technique: A National Neurosurgical Education and Training Centre Analysis of 1236 Consecutive Screws.

Aneurysmal subarachnoid haemorrhage (SAH) is a disease with devastating complications that leads to stroke, permanent neurological deficits and death. Clinical and ex-perimental work has demonstrated the importance of the contribution of delayed cerebral vasospasm (DCVS) indepen-dent early events to mortality, morbidity and functional out-come after SAH. In order to elucidate processes involved in early brain injury (EBI), animal models that reflect acute events of aneurysmal bleeding, such as increase in intracranial pressure (ICP) and decrease in cerebral perfusion pressure, are needed. In the presented arterial shunt model, bleeding is initially driven by the pressure gradient between mean arterial blood pressure and ICP. SAH dynamics (flow rate, volume and duration) depend on physiological reactions and local anatomical intrathecal (cistern) conditions. During SAH, ICP reaches a plateau close to diastolic arterial blood pressure and the blood flow stops. Historical background, anaesthesia, perioperative care and monitoring, SAH induction, technical considerations and advantages and limitations of the rabbit blood shunt SAH model are discussed in detail. Awareness of technical details, physiological characteristics and appropriate monitoring methods guarantees successful implementation of the rabbit blood shunt model and allows the study of both EBI and DCVS after SAH.

The rabbit shunt model of subarachnoid haemorrhage.

Unilateral posterior inferior cerebellar artery (PICA) thrombosis is frequent. However, bilateral PICA thrombosis is rare. Herein we report about an intraoperative visualization of a bilateral thrombosis of the telovelomedullary segment of the PICA. A 74-year-old woman was admitted to our department on day two of a bilateral PICA thrombosis with developing cerebellar infarction. Her Glasgow Coma Scale score dropped from 15 to 13, and cranial computed tomography revealed compression of the fourth ventricle with consecutive occlusive hydrocephalus. After the insertion of an external ventricular drainage, the patient underwent urgent suboccipital decompressive craniectomy with removal of infarcted cerebellar tonsils, which allowed the bilateral visualization of the thrombosed telovelomedullary segments. The surgical access may offer surgical therapeutic options in a hyperacute occlusion, such as thromb-/embolectomy or bypass procedures.

Intraoperative visualization of bilateral thrombosis in the posterior inferior cerebellar artery apparent in the telovelomedullary segment.

17β-estradiol (E2) has been found to induce vasodilation in the cardiovascular system and at physiological levels, resulting in prevention of cerebral vasospasm following subarachnoid hemorrhage (SAH) in animal models. The goal of this study was to analyze the cellular mechanism of nitric oxide (NO) production and its relation to E2, in vitro in brain and peripheral endothelial cells.

Estrogen induces nitric oxide production via nitric oxide synthase activation in endothelial cells.

The New Zealand White (NZW) rabbit model is an established animal model for examining surgical methods to prevent epidural scar formation after spine surgery. As most approaches include complete laminectomy of the rabbit vertebra, this procedure is associated with high morbidity and mortality rates. We examined a less invasive technique, the microsurgical interlaminotomy, for testing epidural substance application in the rabbit spine.

An Interlaminotomy New Zealand White Rabbit Model to Evaluate Novel Epidural Strategies.

The filament perforation model (FPM) in mice is becoming increasingly popular to elucidate the molecular pathogenesis of neuronal injury after subarachnoid hemorrhage (SAH). We evaluated brain MRI in a mouse FPM. A total of 28 male C57Bl/6J mice were used. Seventeen animals underwent SAH induction by FPM. In two animals, transient middle cerebral artery occlusion (MCAo) was induced. Nine mice served as controls. T1-weighted images (T1WI), T2-weighted images (T2WI), T2(∗)-weighted images (T2*WI) and apparent diffusion coefficient maps were acquired at day 0 and at various time points following SAH (range: day 1-6 after SAH). Cerebral blood flow (CBF) analysis by (14)C-iodoamphetamine ((14)C-IMP) autoradiography was conducted in nine animals. Hemorrhage could be best confirmed using T2*WI. The degree of hemorrhage varied. All animals evaluated for ⩾2days were hydrocephalic, which was best seen on T2WI. T2-hyperintensity of the corpus callosum and external capsule, indicating white matter (WM) injury, was present after SAH. Ventricle and WM injury volumes were statistically significantly higher at day 3 compared to day 0. Territorial ischemia was detectable in MCAo but not in SAH. Markedly hypointense cortical veins were visible in the hyperacute and delayed phase after SAH on T2*WI. The (14)C-IMP analysis indicated decreased CBF after SAH. MRI is feasible and useful in evaluating pathophysiological changes over time. T2*WI seems best for SAH detection and grading. The chronological change of hydrocephalus and WM injury could be analyzed. T2*WI illustrated specific signal changes of cortical veins, possibly caused by increased oxygen extraction fraction due to decreased CBF.

Evaluation of a filament perforation model for mouse subarachnoid hemorrhage using 7.0 Tesla MRI.

In subarachnoid hemorrhage (SAH), occurrence of cerebral vasospasm (CVS) mediated by endothelin (ET)-1 might be a result of a compartmental inflammatory response with interleukin (IL)-6 release. We aim to investigate the relationship between ET-1 and IL-6 in association of CVS.

The relationship between IL-6, ET-1 and cerebral vasospasm, in experimental rabbit subarachnoid hemorrhage.

Application of Medishield to the nerve root is common during spinal surgery to create a mechanical barrier from pain mediators and reduce scar formation. However, Medishield's signal characteristics on magnetic resonance imaging (MRI) have not yet been examined.

Magnetic Resonance Imaging Signal Characteristics of Medishield: Early Postoperative Profile in a Rabbit Interlaminotomy Model.

Chronic subdural hematoma (cSDH) is one of the most common neurosurgical diseases typically affecting older people. Many of these patients have coronary artery disease and receive antiplatelet therapy, usually acetylsalicylic acid (ASA). Despite growing clinical relevance, there is still a lack of data focusing on the perioperative management of such patients.

Burr-Hole Drainage for Chronic Subdural Hematoma Under Low-Dose Acetylsalicylic Acid: A Comparative Risk Analysis Study.

With the concept of the hybrid operating room gaining popularity, the authors adapted a hybrid angiographic suite with intraoperative computed tomography (iCT) to evaluate accuracy of pedicle screw placement in spinal fusion. This retrospective review examines how well iCT detected extrapedicular screw violation, to then allow repositioning and potentially avoid revision surgery.

Article	Year
Use of fluorescence to guide resection or biopsy of primary brain tumors and brain metastases. Neurosurgical focus\| PubMed ID: 24484248	2014
Accuracy of Pedicle Screw Placement in the Thoracic and Lumbosacral Spine Using a Conventional Intraoperative Fluoroscopy-Guided Technique: A National Neurosurgical Education and Training Ce... World neurosurgery\| PubMed ID: 24954252	2014
The rabbit shunt model of subarachnoid haemorrhage. Translational stroke research\| PubMed ID: 25326333	2014
Intraoperative visualization of bilateral thrombosis in the posterior inferior cerebellar artery apparent in the telovelomedullary segment. Case reports in neurological medicine\| PubMed ID: 25328728	2014
Estrogen induces nitric oxide production via nitric oxide synthase activation in endothelial cells. Acta neurochirurgica. Supplement\| PubMed ID: 25366614	2015
An Interlaminotomy New Zealand White Rabbit Model to Evaluate Novel Epidural Strategies. Journal of neurological surgery. Part A, Central European neurosurgery\| PubMed ID: 26351871	2015
Evaluation of a filament perforation model for mouse subarachnoid hemorrhage using 7.0 Tesla MRI. Journal of clinical neuroscience : official journal of the Neurosurgical Society of Australasia\| PubMed ID: 27021225	2016
The relationship between IL-6, ET-1 and cerebral vasospasm, in experimental rabbit subarachnoid hemorrhage. Journal of neurosurgical sciences\| PubMed ID: 27759738	2016
Magnetic Resonance Imaging Signal Characteristics of Medishield: Early Postoperative Profile in a Rabbit Interlaminotomy Model. World neurosurgery\| PubMed ID: 27965076	2017
Burr-Hole Drainage for Chronic Subdural Hematoma Under Low-Dose Acetylsalicylic Acid: A Comparative Risk Analysis Study. World neurosurgery\| PubMed ID: 28137546	2017
Validation and accuracy of intraoperative CT scan using the Philips AlluraXper FD20 angiography suite for assessment of spinal instrumentation. British journal of neurosurgery\| PubMed ID: 28282990	2017

Edin Nevzati

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