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BackgroundTo investigate whether patients with critical emergency conditions are seeking or receiving the medical care that they require, we characterized the reality of care for patients presenting with neuro-emergencies during the first phase of the COVID-19 pandemic.MethodsIn this observational, longitudinal cohort study, all neurosurgical admissions that presented to our department between February 1 and April 15 during the COVID-19 pandemic and during the same time period in 2019 were identified and categorized according to the presence of a neuro-emergency, the route of admission, management, and the category of disease. Further, the clinical course of patients with aneurysmal subarachnoid hemorrhage (aSAH) and chronic subdural hematoma (cSDH) was investigated representatively for severe vascular and semi-urgent traumatic conditions that present with a wide variety of symptoms.ResultsDuring the pandemic, the percentage of neuro-emergencies among all neurosurgical admissions remained similar but a larger proportion presented through the emergency department than through the outpatient clinic or by referral (*p = 0.009). The total number of neuro-emergencies was significantly reduced (*p = 0.0007) across all types of disease, particularly in vascular (*p = 0.036) but also in spinal (*p = 0.007) and hydrocephalus (*p = 0.048) emergencies. Patients with spinal emergencies presented 48 h later (*p = 0.001) despite comparable symptom severity. For aSAH, the number of cases, aSAH grade, aneurysm localization, and treatment modality did not change but strikingly, elderly patients with cSDH presented less frequently, with more severe symptoms (*p = 0.046), and were less likely to reach favorable outcome (*p = 0.003) at discharge compared with previous years.ConclusionsDespite pandemic-related restrictive measures and reallocation of resources, patients with neuro-emergencies should be encouraged to present regardless of the severity of symptoms because deferred presentation may result in adverse outcome. Thus, conservation of critical healthcare resources remains essential in spite of fighting COVID-19.

Chemosensory cells in the mucosal surface of the respiratory tract (“brush cells”) use the canonical taste transduction cascade to detect potentially hazardous content and trigger local protective and aversive respiratory reflexes on stimulation. So far, the urogenital tract has been considered to lack this cell type. Here we report the presence of a previously unidentified cholinergic, polymodal chemosensory cell in the mammalian urethra, the potential portal of entry for bacteria and harmful substances into the urogenital system, but not in further centrally located parts of the urinary tract, such as the bladder, ureter, and renal pelvis. Urethral brush cells express bitter and umami taste receptors and downstream components of the taste transduction cascade; respond to stimulation with bitter (denatonium), umami (monosodium glutamate), and uropathogenic Escherichia coli ; and release acetylcholine to communicate with other cells. They are approached by sensory nerve fibers expressing nicotinic acetylcholine receptors, and intraurethral application of denatonium reflexively increases activity of the bladder detrusor muscle in anesthetized rats. We propose a concept of urinary bladder control involving a previously unidentified cholinergic chemosensory cell monitoring the chemical composition of the urethral luminal microenvironment for potential hazardous content.

Aneurysmal subarachnoid hemorrhage (aSAH) caused by mycotic intracranial aneurysms (MIAs) is a rare cerebrovascular condition resulting from bacterial infiltration and arterial wall damage due to systemic or local infections. Due to limited data - often restricted to case reports or small series - no standardized diagnostic or therapeutic strategies exist. Therefore, this study aimed to characterize clinical, radiological, microbiological, and histopathological features of aSAH due to MIAs and to analyze treatment approaches in a larger cohort. We conducted a retrospective analysis of consecutive patients with aSAH from MIAs treated at two neurovascular centers between 2007 and 2024. Inclusion required both suggestive aneurysm morphology (e.g., distal, dysplastic) and evidence of systemic or local infection. Twenty-five patients (64% male, median age 44.7 years) were included. Mean Glasgow Coma Scale on admission was 8 ± 5, with most patients presenting with Hunt and Hess (HH) grades 5 (40%) or 4 (28%). MIAs were most often located at the middle cerebral artery (44%), with a median aneurysm size of 5.9 mm. More than one-third of patients had multiple aneurysms, and 16% developed new MIAs during hospitalization. Infections were associated with prior intracranial surgery (16%) or secondary foci, particularly infective endocarditis (44%). Hospital mortality was 36%, and the mean GOS at discharge was 2, highlighting the severity of the condition.

Unruptured giant intracranial aneurysms (GIA) are those with diameters of 25 mm or greater. As aneurysm size is correlated with rupture risk, GIA natural history is poor. Parent artery occlusion or trapping plus bypass revascularization should be considered to encourage intra-aneurysmal thrombosis when other treatment options are contraindicated. The mechanistic background of these methods is poorly studied. Thus, we assessed the potential of computational fluid dynamics (CFD) and fluid–structure interaction (FSI) analyses for clinical use in the preoperative stage. A CFD investigation in three patient-specific flexible models of whole arterial brain circulation was performed. A C6 ICA segment GIA model was created based on CT angiography. Two models were then constructed that simulated a virtual bypass in combination with proximal GIA occlusion, but with differing middle cerebral artery (MCA) recipient vessels for the anastomosis. FSI and CFD investigations were performed in three models to assess changes in flow pattern and haemodynamic parameters alternations (wall shear stress (WSS), oscillatory shear index (OSI), maximal time averaged WSS (TAWSS), and pressure). General flow splitting across the entire domain was affected by virtual bypass procedures, and any deficiency was partially compensated by a specific configuration of the circle of Willis. Following the implementation of bypass procedures, a reduction in haemodynamic parameters was observed within the aneurysm in both cases under analysis. In the case of the temporal MCA branch bypass, the decreases in the studied parameters were slightly greater than in the frontal MCA branch bypass. The reduction in the magnitude of the chosen area-averaged parameters (averaged over the aneurysm wall surface) was as follows: WSS 35.7%, OSI 19.0%, TAWSS 94.7%, and pressure 24.2%. FSI CFD investigation based on patient-specific anatomy models with subsequent stimulation of virtual proximal aneurysm occlusion in conjunction with bypass showed that this method creates a pro-thrombotic favourable environment whilst reducing intra-aneurysmal pressure leading to shrinking. MCA branch recipient selection for optimum haemodynamic conditions should be evaluated individually in the preoperative stage.

Radiolucent carbon-fiber reinforced PEEK (CFRP) implants have helped improve oncological follow-up and radiation therapy. Here, we investigated the performance of 3D intraoperative imaging and navigation systems for instrumentation and precision assessment of CFRP pedicle screws across the thoraco-lumbar spine. Thirty-three patients with spinal tumors underwent navigated CFRP instrumentation with intraoperative CT (iCT), robotic cone-beam CT (rCBCT) or cone-beam CT (CBCT) imaging. Two different navigation systems were used for iCT-/rCBCT- and CBCT-based navigation. Demographic, clinical and outcome data was assessed. Four blinded observers rated image quality, assessability and accuracy of CFRP pedicle screws. Inter-observer reliability was determined with Fleiss` Kappa analysis. Between 2018 and 2021, 243 CFRP screws were implanted (iCT:93, rCBCT: 99, CBCT: 51), of which 13 were non-assessable (iCT: 1, rCBCT: 9, CBCT: 3; *p = 0.0475; iCT vs. rCBCT). Navigation accuracy was highest using iCT (74%), followed by rCBCT (69%) and CBCT (49%) (*p = 0.0064; iCT vs. CBCT and rCBCT vs. CBCT). All observers rated iCT image quality higher than rCBCT/CBCT image quality (*p < 0.01) but relevant pedicle breaches were reliably identified with substantial agreement between all observers regardless of the imaging modality. Navigation accuracy for CFRP pedicle screws was considerably lower than expected from reports on titanium implants and CT may be best for reliable assessment of CFRP materials.

Purpose: Subsurface blood vessels in the cerebral cortex have been identified as a bottleneck in cerebral perfusion with the potential for collateral remodeling. However, valid techniques for non-invasive, longitudinal characterization of neocortical microvessels are still lacking. In this study, we validated contrast-enhanced magnetic resonance imaging (CE-MRI) for in vivo characterization of vascular changes in a model of spontaneous collateral outgrowth following chronic cerebral hypoperfusion. Methods: C57BL/6J mice were randomly assigned to unilateral internal carotid artery occlusion or sham surgery and after 21 days, CE-MRI based on T2*-weighted imaging was performed using ultra-small superparamagnetic iron oxide nanoparticles to obtain subtraction angiographies and steady-state cerebral blood volume (ss-CBV) maps. First pass dynamic susceptibility contrast MRI (DSC-MRI) was performed for internal validation of ss-CBV. Further validation at the histological level was provided by ex vivo serial two-photon tomography (STP). Results: Qualitatively, an increase in vessel density was observed on CE-MRI subtraction angiographies following occlusion; however, a quantitative vessel tracing analysis was prone to errors in our model. Measurements of ss-CBV reliably identified an increase in cortical vasculature, validated by DSC-MRI and STP. Conclusion: Iron oxide nanoparticle-based ss-CBV serves as a robust, non-invasive imaging surrogate marker for neocortical vessels, with the potential to reduce and refine preclinical models targeting the development and outgrowth of cerebral collateralization.

BackgroundThe main challenge of bypass surgery of complex MCA aneurysm is not the selection of the bypass type, but the initial decision making of how to exclude the affected vessel segment from circulation. The aim of our study was to review our experience with the treatment of complex MCA aneurysms using revascularization and parent artery sacrifice techniques. Based on this, we aimed at categorizing these aneurysms according to specific surgical aspects in order to facilitate preoperative planning for these challenging surgical pathologies.MethodsWe reviewed 50 patients with complex MCA aneurysms that were not clippable but required revascularization and parent artery sacrifice. We report the individual variations of surgical techniques, highlight the technical aspects, and categorize the aneurysms based on their location and orientation.ResultsOf the 50 aneurysms, 56% were giant, 16% large, and 28% < 10 mm, but fusiform. Fourteen percent were previously treated endovascular. Four percent presented with SAH. Ten percent were prebifurcational, 60% involved the bifurcation, and 30% were postbifurcational. Both parent artery sacrifice and bypass strategies were tailored to the individual localization and anatomical relationship of the aneurysm and inflow/outflow arteries (38% proximal inflow occlusion, 42% aneurysm trapping, 20% distal outflow occlusion; 14% STA-MCA bypass, 48% interposition graft, 36%, combined/complex revascularization with reimplantation/in situ techniques). Good outcome (mRS 0–2) rates at discharge and at follow-up were 64% and 84%. Based on our analysis of individual cases, we categorized complex MCA aneurysms into six types and provide individual recommendations for their surgical exploration and treatment by revascularization and parent artery sacrifice.ConclusionComplex MCA aneurysms are among the most challenging vascular lesions and afford highly individualized treatment strategies. Revascularization and parent artery sacrifice provide durable results that are superior to the natural history. Our classification provides a tool for planning and pre-surgical assessment of the intraoperative anatomy of complex MCA aneurysms, helping to assume possible pitfalls.

Purpose Chronic subdural hematoma (cSDH) is a highly prevalent condition that frequently requires surgical evacuation. This is typically achieved through burr hole evacuation, which can be performed under either local anesthesia (LA) or general anesthesia (GA). In the present study, we provide a systematic review and meta-analysis to study and compare the safety and efficacy of cSDH evacuation in LA and GA. Methods Following the PRISMA guidelines, we screened four databases for studies that compared postoperative outcomes after burr hole evacuation of cSDH in LA versus GA. Baseline characteristics and postoperative outcome data were collected, and risk ratios were calculated for each study as well as pooled across records. Random effect models were applied to continuous data points. Bias was assessed using the MINORS tool. Results We identified 22 eligible studies covering 3917 patients in total. LA was associated with decreased risk for complications (p < 0.001), shorter surgery duration (p < 0.001) and hospital stay (p < 0.001). There was no statistically significant association with recurrence rates, postoperative seizure or occurrence of pneumocephalus. In a subanalysis including only data from studies utilizing subdural drainage, results remained largely similar with LA proving advantageous in terms of shorter surgery duration (p < 0.001) and hospital stay (p < 0.001). Conclusion LA may serve as a safe alternative to GA for cSDH surgery, associated with fewer postoperative complications and providing benefits regarding shorter hospital stay and surgery duration.

Adjacent segment stenosis can occur after lumbar fusion surgery, leading to significant discomfort and pain. If further surgeries are required, the choice of the operative technique is an individual decision. In patients without over instability, it is still uncertain whether patients with adjacent spinal stenosis should be treated like primary lumbar spinal stenosis via decompressive surgery alone or with decompression and fusion. This is a retrospective analysis with prospective collected data. We included patients with adjacent segment stenosis after lumbar fusion. Patients with spinal deformity and/or obvious instability and/or significant neuroforaminal stenosis were excluded. All patients were divided into two groups according to the surgical technique that has been used: (a) treated via microsurgical decompression (MDG), (b) decompression and fusion of the adjacent segment (FG). Treatment decision was at discretion of the surgeon. Primary outcome was the need for further lumbar surgery after 1 year. In addition, patient reported outcome was measured via numerical rating scale (NRS), SF-36, Oswestry disability Index (ODI), Pittsburgh Sleep Quality Index (PSQI), and General Depression Scale before and after 1 year after surgery. In a further follow-up, need for additional lumbar surgery was redetermined. Total study population was 37 patients with a median age of 72 years. A total of 86.1% of patients suffered from a proximal adjacent segment stenosis and most common level was L3/4 (51.4%). A total of 61.1% of included patients developed adjacent segment stenosis after fusion of one single lumbar segment. Eighteen patients were included in MDG and 19 patients in FG. Both groups benefited from surgical interventions and there was no significant difference concerning pain, pain associated disability, sleeping, life quality, and mood after 1 year or the need of follow-up surgeries 1 year after primary fusion (5 in MDG vs. 5 in FG, p  = 0.92) and at the second follow-up with a median time after surgery of 30 months (6 in MDG vs. 7 in FG, p  = 0.823). Duration of surgery and hospital stay was significant shorter in MDG. There was no difference concerning operative complications rate. Both groups improved significantly in pain associated disability index, pain in motion, and concerning the sleeping quality. The present study indicates that decompression may not be inferior to decompression and fusion in patients suffering from degenerative adjacent segment stenosis without obvious signs of instability, deformation, and neuroforaminal stenosis after lumbar fusion in short-term follow-up. Due to significant shorter time of surgery, a pure microsurgical decompression may be a sufficient alternative to a decompression and fusion, particular regarding old age of this patient cohort.

Dyspnoea is frequently observed in cancer cachectic patients. Little is known whether this is accompanied by structural or functional alterations of the lung. We hypothesized that in analogy to calorie restriction cancer cachexia leads to loss of alveolar surface area and surfactant. Mice were subjected to subcutaneous injection of Lewis lung carcinoma cells (tumour group, TG) or saline (control group, CG). Twenty-one days later blood samples and the lungs were taken. Using design-based stereology, the alveolar surface area and the lamellar body (Lb) content were quantified. Messenger RNA expression of surfactant proteins, ABCA3 and various growth factors was investigated by quantitative RT-PCR. Intraalveolar surfactant subtype composition was analyzed by differential centrifugation. TG mice showed reduced body weight and anaemia but no reduction of lung volume or alveolar surface area. The volume of Lb was significantly reduced and mRNA levels of ABCA3 transporter tended to be lower in TG versus CG. Surfactant protein expression and the ratio between active and inactive intraalveolar surfactant subtypes were not altered in TG. Growth factor mRNA levels were not different between CG and TG lungs but the tumour expressed growth factor mRNA. Vascular endothelial growth factor was significantly enhanced in blood plasma. The present study demonstrates structural alterations of the lung associated with cancer cachexia. These include reduction of Lb content despite normal intraalveolar surfactant and alveolar surface area. The pulmonary phenotype of the cancer cachectic mouse differs from the calorie restricted mouse possibly due to growth factors released from the tumour tissue.