Anatomy of the pontine arteries and perforators of the basilar artery in humans.

Cerebral blood flow constitutes a critical area of interest for neurologists, neurosurgeons, and interventional radiologists as a social burden related to ischemic stroke, hemorrhagic stroke, and vascular dementia is expected to intensify. There is a great need to develop new and effective therapies, therefore deepening understanding of cerebrovascular anatomy, physiology, and pathology is crucial. The main aim of the study was to develop a comprehensive classification of the pontine arteries considering their typology, relations to the cranial nerves, branching schemes, and superficial pontine blood supply areas. We prepared 100 anatomical specimens of the human brainstem with the basilar artery, the pontine arteries, and the terminal perforating arteries. With the use of microsurgical microscope, we analyzed morphometry of the basilar artery, origins, courses, and branching patterns of the pontine arteries as well as distribution of the terminal perforators in relation to pontine superficial vascular areas and the cranial nerves. Additionally, we studied presence of pontine branches of the superior cerebellar artery (SCA) and anterior inferior cerebellar artery (AICA). Repetitive branching patterns, origins, and courses led us to distinguish five types of the pontine arteries: type 1-the paramedian branches, type 2-the short circumflex branches, type 3-composition of the paramedian and the short circumflex branches, type 4-long circumflex branches, and type 5-median branches penetrating the pons along the basilar sulcus. Types 1, 2, and 4 were described in the literature previously, but the classification did not include the median branches (the most prevalent branches) and frequently occurring combinations of the types 1 and 2. There were seven pontine arteries on both sides on average that presented the following general pattern: the first pontine artery below the SCA is a type 4 vessel called the posterolateral pontine artery and it is followed by a type 2 vessel-the superolateral pontine artery; the next three arteries represent the types 1, 2, and 3 and supply most of the ventral pontine surface; the sixth artery-the anterolateral pontine artery-is a short circumflex branch and the seventh artery, originating below the AICA, represents long circumflex arteries. Occlusion of each of the abovementioned vessels relates to a specific pontine vascular syndrome. As explained by the phylogenesis and ontogenesis of the central nervous system, the pontine arteries are subject to variability. The SCA and the AICA took part in the pontine blood supply in 2.5% and 12.5% of cases, respectively, therefore neurovascular interventions involving the SCA, or the AICA may lead to pontine ischemia. Contact of the pontine arteries with the cranial nerves depends on the vessel type and origin location.

Mechanism of Spontaneous Intracerebral Hemorrhage Formation: An Anatomical Specimens-Based Study.

BACKGROUND: Despite advances in understanding various risk and prognostic factors, spontaneous intracerebral hemorrhage is connected to very high morbidity and mortality, while the therapy is mainly supportive. Understanding of the pathophysiology of initial hematoma expansion is limited due to insufficient clinical data and lack of a suitable animal model. METHODS: We injected 40 anatomic specimens of the basal ganglia with contrast medium, scanned them with a micro-computed tomography scanner and analyzed the results of radiological studies, direct and histological examinations. RESULTS: In 9 cases, micro-computed tomography and histological examinations revealed contrast medium extravasations mimicking intracerebral hematomas. The artificial hematomas spread both proximally and distally along the ruptured perforator and its branches in the perivascular spaces and detached the branches from the adjacent neural tissue leading to destruction of the tissue and secondary extravasations. Moreover, some contrast extravasations skipped to the perivascular spaces of unruptured perforators, created further extravasation sites and aggravated the expansion of the artificial hematoma. There was no subarachnoid extension of any artificial hematoma. CONCLUSIONS: We postulate that a forming basal ganglia intracerebral hematoma spreads initially in the perivascular space, detaches the branches from the neural tissue and causes secondary bleeding. It can also skip to the perivascular space of a nearby perforator. The proposed mechanism of hematoma initiation and formation explains extent of damage to the neural tissue, variability of growth in time and space, creation of secondary bleeding sites, and limited usefulness of surgical interventions. The model is reproducible, the extent of the artificial hematoma can be easily controlled, the rupture sites of the perforating arteries can be determined, and preparation of the model does not require specialized, expensive equipment apart from the micro-computed tomography scanner.

Acute platelet response to aneurysmal subarachnoid hemorrhage depends on severity and distribution of bleeding: an observational cohort study.

Microthrombosis after aneurysmal subarachnoid hemorrhage (aSAH) is considered to initiate neuroinflammation, vessel remodeling, and blood-brain barrier leakage. We aimed to verify the hypothesis that the intensity of thrombogenicity immediately after aSAH depends on the amount and distribution of extravasated blood. This observational cohort study included 37 consecutive aSAH patients admitted no longer than 24 h after ictus. Volumes of subarachnoid and intraventricular hemorrhages as well as the Subarachnoid Hemorrhage Early Brain Edema Scale (SEBES) score were calculated in each case. Platelet system status was described by platelet count (PLT), mean platelet volume (MPV), MPV to PLT ratio, and platelet-large cell ratio (P-LCR). Median hemorrhage volume amounted to 11.4 ml (interquartile range 2.8-26.8 ml). Patients with more severe hemorrhage had lower PLT and higher MPV to PLT ratio (ρ = - 0.49, p < .002; ρ = 0.50, p < .002, respectively). PLT decreased by 2.80 G/l per 1 ml of hemorrhage volume (95% CL 1.30-4.30, p < .001). Further analysis revealed that intraventricular hemorrhage volume was associated with P-LCR and MPV (ρ = 0.34, p < .039; ρ = 0.33, p < .048, respectively), whereas SAH volume with PLT and MPV:PLT ratio (ρ = - 0.40, p < .013; ρ = 0.41, p < .013, respectively). The odds of unfavorable neurological outcome increased 3.95 times per 1 fl of MPV (95% CI 1.19-13.12, p < .025). MPV was independently correlated with SEBES (ρ = 0.44, p < .006). This study demonstrated that the extent and distribution of aneurysmal subarachnoid hemorrhage are related to different types of acute platelet response, which may be interpreted as local and systemic thrombogenicity. Increased mean platelet volume measured in the acute phase of aSAH may identify patients at risk for unfavorable neurological outcomes and may serve as a marker of early brain injury.

Basilar tip fenestration giving rise to Percheron's and mesencephalic arteries.

The basilar bifurcation region is a common site for intracranial aneurysms, as well as it gives rise to a group of perforating arteries that supply the mesencephalon and the thalamus. Complex vascular microanatomy poses a diagnostic and therapeutic challenge for neurosurgeons, neuroradiologists and neurologists. In this paper, we present a previously unreported case of basilar tip fenestration that gave rise to five perforating arteries: the artery of Percheron and four mesencephalic arteries. Due to invaluable clinical significance, the possibility of such a variant must be considered during performing various neurovascular procedures, since e.g., embolization of the fenestration misdiagnosed as an aneurysm would inevitably lead to severe neurological complications (consciousness disturbances, quadriplegia, and sensory loss). Comprehensive knowledge of the neuroanatomy and neuroembryology is crucial to safe execution of intracranial interventions.

Method of creating 3D models of small caliber cerebral arteries basing on anatomical specimens.

The cerebral circulation is a common site of vascular lesions and concurrent hemodynamic accidents, which often lead to serious neurological disabilities. Recent advances in understanding pathogenesis, improving diagnostics and developing new treatment methods for these conditions result from an interdisciplinary approach to the problem - linking clinical sciences, basic medical sciences and hemodynamical analyses. Most common techniques used in such studies include computational fluid dynamics, which allows for development of 3D models of cerebral vasculature, basing on radiological studies. However, these methods remain flawed, mainly because of their spatial resolution, which is not high enough to visualize the smallest arterial branches (perforating branches) in the models. That leaves the perforators (<1.0 mm) out of most of the contemporary studies, whilst their clinical importance is widely recognized in clinical practice. Obstruction of these vessels by atherosclerotic plaques, thrombi or implantation of flow diverting stents may result in neurological complications such as paralysis or coma. Our research team has recently developed a new method of creating 3D models of the cerebral arterial system based on anatomical specimens and micro computed tomography (micro-CT). We have infused fresh brainstem vasculature specimens with contrast medium, subsequently scanned them using an industrial-grade micro-CT system and finally, created spatial models, which included branches of diameter less than 0.1 mm. None of the current methods have been able to produce models of detail as high as this, which allows us to presume, that our procedure may open up new opportunities for hemodynamical studies within cerebral circulation and beyond.

Dynamics of humoral response to coronavirus antigens among employees of a designated COVID­19 hospital: an observational study.

INTRODUCTION: During the COVID­19 pandemic studies on workplace safety of hospital staff taking care of patients with this disease are a high priority. We decided to analyze the results of opportunistic screening for anti-SARS­CoV-2 antibodies among employees of a designated COVID-19 center. OBJECTIVES: The aim of the study was to investigate whether potential exposition to SARS­CoV-2 antigens is reflected in the results of serological studies. PATIENTS AND METHODS: Every employee who performed at least a single test between April 21 and July 20, 2020 was included in the study. The tests assessed the levels of immunoglobulin (Ig) G and IgM+IgA. Employees working in direct contact with COVID­19 patients and those participating in aerosol­generating procedures were identified. RESULTS: The results of 2455 tests taken by 1572 employees were analyzed. A total of 357 participants (22.7%) had at least 1 positive or equivocal result during the study period. Linear mixed models revealed gradual increases in mean levels of both IgG and IgM+IgA antibodies among employees with all negative results. The rate of change was higher among persons who had direct contact with COVID­19 patients and the highest rate of change was observed among individuals participating in aerosol­generating procedures. CONCLUSIONS: We detected developing humoral immune response to a new set of coronavirus antigens among the study group. It is possible that employees of designated COVID­19 centers are regularly exposed to noninfectious doses of SARS­CoV-2 or its antigens.

Transformation of a large multi-speciality hospital into a dedicated COVID-19 centre during the coronavirus pandemic.

INTRODUCTION: The article describes the process of converting a large multi-specialized hospital into one dedicated to COVID-19 patients, and present established standards of work organization in all the wards and training system of the medical and supporting staff. The several weeks pandemic of the COVID-19 disease has forced the healthcare systems of numerous countries to adjust their resources to the care of the growing number of COVID-19 patients. Managers were presented with the challenge of protecting the healthcare workers from transmission of the disease within medical institutions, and issues concerning the physical and psychological depletion of personnel. MATERIAL AND METHODS: Based on analyses of the structure and work processes in Central Clinical Hospital (CCH) reconstructive strategic plan was developed. It included: division of existing wards into observation and isolation wards; installing locks; weekly plan for supplying personal protection equipment (PPE); designating new access to the hospital and communication routes; training of medical and supporting staff. The plan was implemented from the first days of conversion of the hospital. RESULTS: The wards of the CCH were converted for observation and isolation, and each one was fitted with sanitary locks. There was a big improvement in the supply of PPE for the medical staff. Separation of the 'dirty' and 'clean' parts of the CCH were attained, and widespread intensive training not only protected personnel against infections, but also diminished unrest which was discernable at the beginning of conversion. CONCLUSIONS: The transformation efforts will ultimately be appraised at the end of the epidemic, but the data looks encouraging. Two weeks after conversion, the testing of hospital Staff was started and by the end of April, 459 tests were had been conducted, of which only 11 were positive.