A primer to vascular anatomy of the brain: an overview on anterior compartment.

PURPOSE: Knowledge of neurovascular anatomy is vital for neurosurgeons, neurologists, neuro-radiologists and anatomy students, amongst others, to fully comprehend the brain's anatomy with utmost depth. This paper aims to enhance the foundational knowledge of novice physicians in this area. METHOD: A comprehensive literature review was carried out by searching the PubMed and Google Scholar databases using primary keywords related to brain vasculature, without date restrictions. The identified literature was meticulously examined and scrutinized. In the process of screening pertinent papers, further articles and book chapters were obtained through analysis and additional assessing of the reference lists. Additionally, four formalin-fixed, color latex-injected cadaveric specimens preserved in 70% ethanol solution were dissected under surgical microscope (Leica Microsystems Inc, 1700 Leider Ln, Buffalo Grove, IL 60089 USA). Using microneurosurgical as well as standard instruments, and a high-speed surgical drill (Stryker Instruments 1941 Stryker Way Portage, MI 49002 USA). Ulterior anatomical dissection was documented in microscopic images. RESULTS: Encephalic circulation functions as a complex network of intertwined vessels. The Internal Carotid Arteries (ICAs) and the Vertebral Arteries (VAs), form the anterior and posterior arterial circulations, respectively. This work provides a detailed exploration of the neurovascular anatomy of the anterior circulation and its key structures, such as the Anterior Cerebral Artery (ACA) and the Middle Cerebral Artery (MCA). Embryology is also briefly covered, offering insights into the early development of the vascular structures of the central nervous system. Cerebral venous system was detailed, highlighting the major veins and tributaries involved in the drainage of blood from the intracranial compartment, with a focus on the role of the Internal Jugular Veins (IJVs) as the primary, although not exclusive, deoxygenated blood outflow pathway. CONCLUSION: This work serves as initial guide, providing essential knowledge on neurovascular anatomy, hoping to reduce the initial impact when tackling the subject, albeit the intricate vasculature of the brain will necessitate further efforts to be conquered, that being crucial for neurosurgical and neurology related practice and clinical decision-making.

Posterior vascular anatomy of the encephalon: a comprehensive review.

PURPOSE: This article presents a comprehensive exploration of neurovascular anatomy of the encephalon, focusing specifically on the intricate network within the posterior circulation and the posterior fossa anatomy; enhancing understanding of its dynamics, essential for practitioners in neurosurgery and neurology areas. METHOD: A profound literature review was conducted by searching the PubMed and Google Scholar databases using main keywords related to neurovascular anatomy. The selected literature was meticulously scrutinized. Throughout the screening of pertinent papers, further articles or book chapters were obtained through additional assessment of the reference lists. Furthermore, four formalin-fixed, color latex-injected cadaveric specimens preserved in 70% ethanol solution were dissected under surgical microscope (Leica Microsystems Inc, 1700 Leider Ln, Buffalo Grove, IL 60089, USA), using microneurosurgical as well as standard instruments, and a high-speed surgical drill (Stryker Instruments 1941 Stryker Way Portage, MI 49002, USA). Ulterior anatomical dissection was performed. RESULTS: Detailed examination of the basilar artery (BA), a common trunk formed by the union of the left and right vertebral arteries, denoted a tortuous course across the basilar sulcus. Emphasis is then placed on the Posterior Inferior Cerebellar Artery (PICA), Anterior Inferior Cerebellar Artery (AICA) and Superior Cerebellar Artery (SCA). Each artery's complex course through the posterior fossa, its divisions, and potential stroke-related syndromes are explored in detail. The Posterior Cerebral Artery (PCA) is subsequently unveiled. The posterior fossa venous system is explained, categorizing its channels. A retrograde exploration traces the venous drainage back to the internal jugular vein, unraveling its pathways. CONCLUSION: This work serves as a succinct yet comprehensive guide, offering fundamental insights into neurovascular anatomy within the encephalon's posterior circulation. Intended for both novice physicians and seasoned neuroanatomists, the article aims to facilitate a more efficient clinical decision-making in neurosurgical and neurological practices.

Cervical anterior spinal artery infarction associated with anomalous vertebral artery: a case report.

We report a unique case of cervical anterior spinal artery (ASA) infarction in a 49-year-old male with hypercholesterolemia and sleep apnea. The patient experienced sudden cervical pain, quadriparesis, areflexia, and urinary incontinence after swallowing a large food bolus. Imaging revealed an infarction at the C3-C5 levels and an anomalous right vertebral artery (VA) originating from the thoracic aorta, tightly enclosed between the aorta and a vertebral column with an anterior osteophyte. This aberrant VA was the primary vascular supply to the ASA, with no contribution from the left VA or supreme intercostal arteries. We propose that transient injury to the right VA, induced by compression between the aortic arch, the food bolus, and the osteophyte, led to temporary hypoperfusion of the ASA, causing a watershed ischemic injury in the mid cervical cord's anterior gray matter. The article also provides an in-depth discussion of the developmental and clinical characteristics associated with this rare vascular anomaly.

Debilitating trigeminal neuralgia secondary to idiopathic intracranial hypertension.

Idiopathic intracranial hypertension (IIH) is characterized by raised intracranial pressure with unknown etiology. The most common neurological manifestations are headache and visual loss. Often, other cranial nerve impairments are also found, most commonly in the VI nerve. Trigeminal neuralgia (TN) is a debilitating condition that is most frequently caused by neurovascular pathology, but TN secondary to IIH is a rare and poorly described topic. Possible explanations of TN in these patients include the distortion of the local anatomy at CN entry zones and fluid displacement causing distortion of the Meckel's cave. In the case below we describe the clinical course of an obese female patient with TN-like pain who underwent a ventriculoperitoneal shunt to treat IIH and experienced complete resolution of both conditions.

Chiari Malformation Type 1 and Semi-Sitting Position-A Suitable Alternative for Patients with High BMI.

OBJECTIVE: Chiari I malformation results from a mismatch between the posterior fossa bones and neural components. Management usually relies on surgical treatment. Despite being the most common assumed positioning, the prone position can be challenging in high body mass index (BMI) patients (>40 kg/m2). METHODS: Between February 2020 and September 2021, 4 consecutive patients with class III obesity underwent posterior fossa decompression. The authors describe nuances of the positioning and perioperative details. RESULTS: No perioperative complications were reported. These patients are at a lower risk of bleeding and increased intracranial pressure as a consequence of low intra-abdominal pressure and venous return. In this context, the semi-sitting position, with the aid of accurate monitoring for venous air embolism, seems to be an advantageous surgical position in this group of patients. CONCLUSIONS: We present our results and technical nuances on positioning high BMI patients for posterior fossa decompression using a semi-sitting position.

The Role of EGFR Amplification in Deep Venous Thrombosis Occurrence in IDH Wild-Type Glioblastoma.

Introduction: Glioblastoma (GBM) patients have a 20-30 incidence of venous thromboembolic events. EGFR is a widely used prognostic marker for many cancers. Recent lung cancer studies have described relationships between EGFR amplification and an increased incidence of thromboembolic complications. We aim to explore this relationship in glioblastoma patients. Methods: Two hundred ninety-three consecutive patients with IDH wild-type GBM were included in the analysis. The amplification status of EGFR was measured using fluorescence in situ hybridization (FISH). Centromere 7 (CEP7) expression was recorded to calculate the EGFR-to-CEP7 ratio. All data were collected retrospectively through chart review. Molecular data were obtained through the surgical pathology report at the time of biopsy. Results: There were 112 subjects who were EGFR-amplified (38.2%) and 181 who were non-amplified (61.8%). EGFR amplification status was not significantly correlated with VTE risk overall (p = 0.2001). There was no statistically significant association between VTE and EGFR status after controlling for Bevacizumab therapy (p = 0.1626). EGFR non-amplified status was associated with an increased VTE risk in subjects greater than 60 years of age (p = 0.048). Conclusions: There was no significant difference in occurrence of VTE in patients with glioblastoma, regardless of EGFR amplification status. Patients older than 60 years of age with EGFR amplification experienced a lower rate of VTE, contrary to some reports on non-small-cell lung cancer linking EGFR amplification to VTE risk.

Endoscopic endonasal optic nerve sheath decompression (EONSD) for idiopathic intracranial hypertension: Technical details and meta-analysis.

BACKGROUND: The neurosurgical management of idiopathic intracranial hypertension (IIH) remains controversial. Although shunting and newer endovascular stenting techniques are part of the neurosurgical armamentarium to treat medically refractory IIH symptoms, optic nerve sheath fenestration has traditionally been performed by ophthalmologists. OBJECTIVE: We present a detailed cadaveric dissection that simulates the endoscopic endonasal optic nerve sheath decompression (EONSD) technique along with the literature review. METHODS: EONSD was performed in four freshly injected cadaveric specimens. Additionally, a systematic review from different electronic databases has been done. RESULTS: Bilateral EONSD was performed in all specimens without significant technical difficulties. Based on our experience, there is no need to expose the periorbita or orbital apex. The primary anatomic landmarks were the optic canal, the lateral opticocarotid recess, the tuberculum, the limbus, and the clinoid segment of the internal carotid artery. Based on the systematic review, 68 patients (77.9% female) underwent EONSD, with a mean age of 33.4 ± 6.9 years in adult patients. Follow-up ranged from 3 to 58 months across different studies. The pooled meta-analysis showed headache, papilledema, and visual disturbance improvement in 78% [95%CI 0.65-0.90], 72% [95%CI 0.61-0.83], and 88% [95%CI 0.80-0.96] of cases who underwent EONSD, respectively. The subgroup analysis showed there was no statistically significant difference between unilateral and bilateral EONSD in terms of different measured outcomes. CONCLUSION: EONSD is a feasible surgical procedure that may obviate the need for shunting in patients with IIH. Although clinical studies showed that EONSD is a safe and effective technique, further studies are required to establish the preferences of either unilateral or bilateral approaches.

Anatomical Description and Literature Review of the Endoscopic Endonasal Transclival Transodontoid Approach Combined with Endoscopic Transoral Decompression to the Anterior Craniovertebral Junction: A New Strategy.

OBJECTIVE: To describe and evaluate the steps required to perform a combined endoscopic endonasal/transoral transclival transodontoid approach for anterior decompression of the craniovertebral junction. METHODS: The endoscopic endonasal transclival transodontoid approach combined with endoscopic transoral decompression was performed on 4 cadaveric specimens. Evaluation of this combined technique; a review of the literature; and the nuances, advantages, and pitfalls are reported. RESULTS: Adequate wide anterior decompression was achieved in all specimens. This combined approach allowed the preservation of the anterior arch of C1 without injuring the eustachian tube anatomy and avoiding internal carotid artery manipulation. CONCLUSIONS: Mastery of both techniques allows for a safe and comfortable surgical corridor. The transoral and transnasal approaches should not be considered as either/or techniques, but rather as a complement to each other. However, as with all new or developing techniques, there is a steep learning curve, which requires ample training in the skull base laboratory.

Safety of craniotomy for brain tumor resection in octogenarians and older patients - a matched - cohort analysis.

INTRODUCTION: The incidence of brain tumors has increased in elderly population overtime. Their eligibility to a major surgery remains a questionable subject. This study evaluated prognostic factors and 30-days morbidity and mortality in octogenarian population who underwent craniotomy for resection of brain tumor. MATERIALS AND METHODS: A total of 154 patients were divided into two different groups: patients above 80 years old and patients below 65 years old. In both groups, patients were stratified based on diagnosis with benign tumors [meningioma] and malignant tumors [high-grade gliomas and metastases]. Multivariable logistic regression model with backward elimination method was utilized to identify the independent risk factors for 30-days readmission and post-operative complications. RESULTS: The analysis revealed no significant difference in 30-day readmission (p = 0.7329), 30-day mortality (0.6854) or in post-operative complication (p = 0.3291) between age ≥ 80 and age ≤ 65 groups. A longer length of stay (LOS) was observed in the older patients (p = 0.0479). There was a significant difference in the pre-post KPS between the two groups (p < 0.0001). ASA (p = 0.0315) and KPS (p = 0.071) were found as important prognostic factors associated with post-operative mortality in both groups. CONCLUSION: Octogenarians can withstand craniotomy without any significant increase in 30-day readmission, 30-day mortality and post-operative complications as compared to patients younger than age 65. The ASA score (>3) and/or KPS (<70) were the most important prognostic factors for 30-days readmission and mortality.

Trigeminal Neuralgia-Step-by-Step DYNA-Computed Tomography-Assisted Balloon Compression Rhizotomy.

Trigeminal nerve balloon compression (TNBC)1-3 can provide immediate therapeutic relief to patients suffering from trigeminal neuralgia. This is a particularly effective treatment option for patients who are not eligible for surgical procedures (i.e., elderly patients or patients with multiple comorbidities) or for patients who have had an insufficient response to microvascular decompression. TNBC can also be used as a bridge treatment before stereotactic radiosurgery. Use of intraoperative computed tomography-like images using a C-arm system (DYNA-CT) imaging facilitates the TNBC procedure.4,5 Three-dimensional DYNA-CT imaging with needle guidance allows for precise needle advancement and insertion through the foramen ovale. DYNA-CT enables the direct visualization and avoidance of vascular structures such as the carotid or internal maxillary arteries and results in decreased procedure times and complications. The authors present a step-by-step video demonstrating the use of intraoperative DYNA-CT needle guidance for TNBC (Video 1). A Siemens Artis Zee Biplane system is used for the procedure. A comprehensive description of all elements of the procedure is provided including balloon preparation, needle trajectory planning, needle advancement, 3-dimensional confirmation of the needle's depth and path, balloon placement, balloon inflation, and balloon removal. Tips and optimal strategies are presented. Advantages of using DYNA-CT for needle guidance include the reduction of fluoroscopy dose and fluoroscopy time. The average dose area product during conventional percutaneous balloon compression in prior studies was 1137 mGycm2, with a mean fluoroscopic time of 62 seconds.6 In our experience, the mean fluoroscopy dose is 274 mGycm2 and the total fluoroscopic time is about 45 seconds. Furthermore, during the DYNA-CT acquisition, the neurointerventional team stays outside the room during the DYNA-CT, which reduces the cumulative radiation to the operator. DYNA-CT needle guidance facilitates precise advancement of the needle into the foramen ovale and positioning of the balloon in the Meckel cave during TNBC. It is a safe and feasible technique that allows for the visualization and avoidance of important structures such as the internal carotid artery or the internal maxillary artery, resulting in decreased procedure times and complications.

Wide Dissection Trans-Sulcal Approach for Resection of Deep Intra-Axial Lesions in Eloquent Brain Areas.

Introduction: Resection of intra-axial tumors (IaT) in eloquent brain regions risks major postoperative neurological deficits. Awake craniotomy is often used to navigate these areas; however, some patients are ineligible for awake procedures. The trans-sulcal approach (TScal) was introduced to reduce parenchymal trauma during tumor resection. We report our experiences utilizing TScal for resection of deep IaT located in eloquent areas. Materials and Methods: This is a single-center retrospective analysis of patients who underwent IaT resection in eloquent areas via TScal from January 2013 to April 2021. Seventeen cases were reviewed, and relevant data was collected. Fluorescence-guided surgery with 5-aminolevulinic acid (ALA) and intraoperative ultrasound was performed in some cases. Results: Seventeen patients (10 males, 7 females) averaging 61.2 years-old (range, 21-76) were included in this study. Average length of stay was 4.8 days, and only 2 patients (11.8%) required hospital readmission within 30 days. Gross total resection (GTR) was achieved in 15 patients (88.2%), while subtotal resection occurred in 2 patients (11.8%). Eleven patients (64.7%) reported full resolution of symptoms, 4 patients (23.5%) reported deficit improvement, and 2 patients (11.8%) experienced no change from their preoperative deficits. No patient developed new permanent deficits postoperatively. Discussion: GTR, preoperative deficit reduction, and complications were comparable to awake craniotomy and other TScal studies. Ancillary intraoperative techniques, such as brain mapping, 5-ALA and intraoperative ultrasound, are afforded by TScal to improve resection rates and overall outcomes. Conclusions: TScal can be an option for patients with deep lesions in eloquent areas who are not candidates for awake surgeries.

Transcavernous Approach for Microsurgical Clipping of Ruptured Right Superior Cerebellar Artery Aneurysm with Cadaveric Stepwise Video Illustration.

Superior cerebellar artery (SCA) aneurysms are rare. The management options are not well defined. There is increasing role of endovascular treatment for all aneurysms, especially for aneurysms of the posterior circulation. However in some situations (wide base, dysmorphic features) coiling is not feasible. The surgical management of these aneurysms has its own distinct complexity and requires careful planning. The classic pterional or subtemporal approaches had its own limitation in proper visualization of the neurovascular anatomy. In this video, we describe the technical nuances of transcavernous sinus approach for microsurgical clipping SCA and A-comm aneurysms. We present the case of a 67-year-old RHF who presented with ruptured right-sided SCA aneurysm. She complained of Headache, confusion, and double vision. On physical examination, she had no focal deficits and was Hunt and Hess grade 3. A brain computed tomography (CT) scan revealed a subarachnoid hemorrhage Fisher's grade 4. A brain CT angiography (CTA) demonstrated an aneurysm at the origin of right SCA. The patient had failed attempt of endovascular coiling and she underwent microsurgical clipping. Stepwise demonstration of the approach with cadaveric anatomical dissection is illustrated. The technique presented here allows for safe clipping of the aneurysm through the cavernous sinus. The approach allows for good exposure of the aneurysm and the surrounding structures. Care is taken to visualize the perforators to avoid any devastating brain stem infarction during the clipping. The transcavernous sinus is a robust approach with good visualization of the neurovascular structures allowing safe aneurysm clipping in this location. The link to the video can be found at: https://youtu.be/oE-HyDASiKM .

Percutaneous balloon compression technique using intraoperative contrasted DynaCT for the treatment of refractory trigeminal neuralgia: initial experience.

OBJECTIVE: Percutaneous balloon compression (BC) is a well-established technique that can provide immediate relief to patients suffering from trigeminal neuralgia (TN). The general procedure of BC uses fluoroscopy imaging to guide the needle through the foramen ovale (FO). The aim of this study was to describe our experience with a novel technique using intraoperative contrast-enhanced DynaCT as an adjunct for more accurate and safer guidance of the needle to the FO. METHODS: In this study, DynaCT was used to perform BC in 20 TN cases. The three-dimensional path of the needle was pre-planned using DynaCT obtained during the administration of IV contrast. The FO was accessed in a single pass along the path pre-determined from the DynaCT images, avoiding any major arteries and veins. DynaCT was also used for confirmation of the final position of the needle prior to insertion of the balloon as well as for confirmation of the position of the balloon after inflation. RESULTS: Intravenous contrast-enhanced DynaCT-guided percutaneous BC allowed precise advancement and positioning of the needle within the FO. It facilitated cannulation of the FO along a pre-determined path that avoided any major vascular structures. Clinical outcomes were excellent-all patients had a quick postoperative recovery, and there were no complications. CONCLUSIONS: The advantages of the contrast-enhanced DynaCT-guided technique include a single precise needle pass and avoidance of vessel injury. Precise placement of the balloon into different aspects of the FO can target trigeminal branches more selectively and allow for a better outcome.

Blood Supply of Cranial Nerves Passing Through the Cavernous Sinus: An Anatomical Study and Its Implications for Microsurgical and Endoscopic Cavernous Sinus Surgery.

BACKGROUND: Despite improvements in surgical techniques, cranial nerve (CN) deficits remain the most frequent cause of disability following cavernous sinus (CS) surgery. The most common tumor affecting the CS is meningioma. They originate from lateral wall and have their blood supply from meningohypophyseal trunk (MHT) and inferolateral trunk (ILT). Pituitary adenomas commonly invade the CS through its medial wall and receive blood supply form medial branches of the internal carotid artery (ICA) (superior and inferior hypophyseal arteries). Some tumors may grow within the CS (e.g. trigeminal schwannomas, hemangiomas). These tumors are fed by all the intracavernous ICA branches. Tumors involving the CS may also displace the neurovascular structures, therefore, a better understanding of intracavernous neurovascular anatomy may reduce the postoperative morbidity associated with approaching CS tumors. In this anatomical study, the anatomic variations and their clinical implications of the intracavernous CNs' blood supply were evaluated through transcranial and endonasal routes. METHODS: Twenty sides of ten adult cadaveric formalin-fixed, latex-injected specimens were dissected in stepwise fashion under microscopic and endoscopic magnification. The origin and course of the intracavernous ICA branches supplying the intracavernous CNs are studied. RESULTS: The proximal segment of the oculomotor nerve receives blood supply from the ILT in 85%, and the tentorial artery of the MHT in 15% of specimens. The distal segment is exclusively supplied by the ILT. The proximal trochlear nerve receives blood supply from the ILT (75%) and the tentorial artery (25%); the distal segment is exclusively supplied by the superior orbital branch. The proximal third of the abducens nerve receives its vascularity exclusively from the dorsal meningeal artery, and its middle and distal thirds from the ILT. The ophthalmic and proximal maxillary segments of the trigeminal nerve also receive blood supply from the ILT. The distal maxillary segment is supplied by the artery of the foramen rotundum. All ILT branches terminate on the inferomedial aspects of the intra-cavernous CNs. Extensive anastomoses are found between ILT branches and the branches arising from external carotid artery. CONCLUSION: Understanding the anatomy of the intracavernous ICA's branches is important to improving surgical outcomes with tumors involving the CS.

Intracranial Plasmacytoma Mimicking a Cavernous Sinus Meningioma.

Extramedullary plasmacytomas involving the cavernous sinus are rare manifestations of multiple myeloma, and management strategies for such a pathology are not extensively discussed in the literature. In this case report, we describe the case of a patient presenting with a cavernous sinus syndrome secondary to a presumed meningioma. Surgical intervention was avoided as a computed tomography-guided biopsy was performed yielding the diagnosis of a cavernous sinus plasmacytoma. Neurointerventional radiology obtained the cavernous sinus mass biopsy using an approach through the maxillary bone and sinus. Histopathology identified sheets of atypical plasma cells, and the patient was referred to radiation oncology for further management.

A rare combination of carotid artery congenital abnormalities: understanding the embryology and clinical associations.

Duplication of an extracranial internal carotid artery, a retropharyngeal carotid transposition, an aberrant internal carotid artery in the middle ear, and a persistent stapedial artery are each individually uncommon vascular variants. In this case report, we discuss a rare occurrence of all four of these variants in a single individual who presented to our emergency department with a complaint of dizziness and a recent fall. Included in the discussion is pertinent embryology and clinical associations.