Proximal Branches of the Anterior Cerebral Artery: Anatomic Study and Applications to Endoscopic Endonasal Surgery

The prevalence and anatomy of recurrent artery of Heubner: a meta analysis with neurosurgical considerations

BACKGROUND

The recurrent artery of Heubner (RAH) is typically the largest medial lenticulostriate branch of the anterior cerebral artery (ACA). Neurosurgical procedures such as aneurysm treatment on the anterior part of the circle of Willis can result in damage of the RAH leading to neurological deficits. The aim of this study was to identify the gaps and provide comprehensive data on the prevalence and anatomical characteristics of the RAH with neurosurgical considerations.

METHODS

The major electronic databases were thoroughly searched to identify the eligible studies. The information concerning study type, geographical origin, prevalence of the RAH, course and origin of the RAH, symmetry of origin and number of RAHs in each hemisphere, and morphometric data were extracted. The PRISMA guidelines were rigorously followed throughout the study. The AQUA tool was used to evaluate the reliability of included studies.

RESULTS

A total of 34 studies (n = 3645 hemispheres) were included in the meta-analysis. The analysis revealed that the RAH was present in 97.5% (95%CI: 95.5-98.6) of the hemispheres, originating most frequently from the A2 segment (42.2%, 95%CI: 35.0-49.7) or the ACoA-ACA junction (41.6%, 95%CI: 34.0-49.6), and coursing anteriorly (47.6%, 95%CI: 38.7-56.6) or superiorly (43.9%, 95%CI: 34.4-53.8) in relation to ACA. Almost a quarter of patients had more than one RAH, which was on average 22.82 mm (SD: 1.35, 95%CI: 20.16-25.47; I2 = 99.1%, p < 0.01) long and reached 0.76 mm (SD: 0.05, 95%CI: 0.66-0.85; I2 = 99.4%, p < 0.01) in diameter.

CONCLUSIONS

As the RAH is present in the majority of the population, it is important to be aware of the wide variations in its anatomy. This will help to prevent postoperative neurological deficits by avoiding undesirable complications during surgeries that are performed in close proximity to the anterior segment of the circle of Willis.

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.

An analytical method informed by clinical imaging data for estimating outlet boundary conditions in computational fluid dynamics analysis of carotid artery blood flow

Stroke occur mainly due to arterial thrombosis and rupture of cerebral blood vessels. Previous studies showed that blood flow-induced wall shear stress is an essential bio marker for estimating atherogenesis. It is a common practice to use computational fluid dynamics (CFD) simulations to calculate wall shear stress and to quantify blood flow. Reliability of predicted CFD results greatly depends on the accuracy of applied boundary conditions. Previously, the boundary conditions were estimated by varying values so that they matched the clinical data. It is applicable upon the availability of clinical data. Meanwhile, in most cases all that can be accessed are arterial geometry and inflow rate. Consequently, there is a need to devise a tool to estimate boundary values such as resistance and compliance of arteries. This study proposes an analytical framework to estimate the boundary conditions for a carotid artery based on the geometries of the downstream arteries available from clinical images.

Assessment of Arterial Configurations of the Suprachiasmatic Region from the Endoscopic Endonasal Perspective: A Cadaveric Anatomical Study

BACKGROUND

Endoscopic endonasal surgery has proved to offer a practical route to treat suprasellar lesions, including tumors and vascular pathologies. Understanding the different configurations of the anterior cerebral communicating artery (ACoA) complex (ACoA-C) is crucial to properly navigate the suprachiasmatic space and decrease any vascular injury while approaching this region through an endonasal approach.

METHODS

An endoscopic endonasal transplanum-transtubercular approach was performed on 36 cadaveric heads (72 sides). The variations of the ACoA-C and feasibility of reaching its different components were analyzed. The surgical area exposure of the lamina terminalis was also quantified before and after mobilization of the ACoA-C.

RESULTS

The typical ACoA-C configuration was found in 41.6% of specimens. The following 2 main variations were identified: accessory anterior cerebral artery segment 2 (5, 13.9%) and common trunk of anterior cerebral artery with absence of ACoA (5, 13.9%). Of 101 recurrent arteries of Heubner, 96 (95.0%) were identified within 4 mm proximal or distal to the ACoA. The mean lamina terminalis exposure area was 33.1 ± 16.7 mm², which increased to 59.9 ± 11.9 mm² after elevating the ACoA.

CONCLUSIONS

A considerable amount of variation of the ACoA-C can be found through an endoscopic endonasal transplanum-transtubercular approach. These configurations determine the feasibility of lamina terminalis exposure and the complexity of reaching the ACoA. Assessment of ACoA morphology and its adjacent structures is crucial while approaching the suprachiasmatic through a transnasal corridor.

Surgical anatomy and technical nuances of the endoscopic endonasal approach to the anterior cranial fossa

Endoscopic endonasal approaches (EEA) to the skull base have significantly impacted the management of lesions located in the cranial base. Specifically, lesions arising from the anterior cranial fossa, such as pituitary macroadenomas, craniopharyngiomas meningiomas and craniofacial malignancies have benefited from the development of such approaches. Understanding of the anatomy of the anterior fossa is of utmost importance for the successful selection of the approach and application of surgical techniques in EEA. In the current manuscript, we review the most relevant points of surgical anatomy and nuances of the surgical technique of EEA to the anterior fossa. Anatomical landmarks for the transtuberculum transplanum and transcribriform approaches are discussed and a step-by-step description for those approaches is presented. We reinforce that safe and effective application of such techniques follow the same principles of other skull base surgery techniques: mastering of surgical anatomy, adequate case selection, correct instrumentation and surgical experience.

Endoscopic endonasal resection of a large tuberculum sella meningioma

Over the past three decades, endoscopic endonasal surgery has unlocked new corridors to treat a wide spectrum of ventral skull base lesions. Tuberculum sella meningiomas represent one of the most ideal pathologies for ventral skull base access. Traditionally, these lesions were approached primarily through various subfrontal and frontal-lateral transcranial approaches that have unfortunately been shown to be associated with worsening visual decline postoperatively. The endoscopic endonasal approach is now being attempted by more surgeons and leverages an infrachiasmatic trajectory that provides direct access to the tuberculum sella where most of the vascular supply for these lesions can be taken early, facilitating more efficient surgical resection and mitigating the risk of optic nerve injury. Here we review a challenging case of a large (∼3 cm) tuberculum sella meningioma, encasing critical vessels off the circle of Willis and resected via an endoscopic endonasal approach. We discuss the technical nuances and relevant surgical anatomy of this approach and highlight important considerations in the safe and successful removal of these meningiomas. We show that certain tumors that appear to encase the supraclinoidal carotid artery can be fully resected via an endonasal approach with precise surgical technique and adequate exposure. Furthermore, this case illustrates the risk of injuring a key perforating vessel from the anterior communicating artery complex, called the subcallosal artery. Injury to this vessel is highly associated with tumors like the one presented here that extend into the suprachiasmatic space between the optic chiasm and the anterior communicating complex. Meticulous surgical dissection is required to preserve this perforating vessel as well as branches from the superior hypophyseal artery. Finally, we review our current closure techniques for these challenging approaches and discuss the use of a lumbar drain for 3 days to lower CSF leak rates.

The video can be found here: https://youtu.be/mafyXi5B0MA.

Lateral nasal wall flap for endoscopic reconstruction of the skull base: anatomical study and clinical series

BACKGROUND

The lateral nasal wall (LNW) flap provides vascularized endonasal reconstruction primarily in revision surgery. Although the harvesting technique and reconstructive surface have been reported, the arterial supply to the LNW flap and its clinical implications is not well defined. This study presents anatomical dissections to clarify the vascular supply to this flap, and the associated clinical outcomes from this reconstructive technique.

METHODS

The course and branching pattern of the sphenopalatine artery (SPA) to the LNW were studied in 6 vascular latex-injected heads (11 LNW flaps total). Patients undergoing an LNW flap since 2008 were identified and the underlying pathology, indication, flap viability, and clinical outcomes were retrospectively analyzed.

RESULTS

The inferior turbinate artery arises from the LNW artery and divides into 2 branches at the most posterior aspect of the inferior turbinate bone. A smaller-caliber superficial branch travels anteriorly and branches to the LNW. A larger dominant branch travels into the inferior meatus and tangentially supplies the nasal floor. Twenty-four patients with sellar or posterior cranial fossa (PCF) defects were reconstructed with an LNW flap. Postoperative contrast enhancement of the LWN flap was identified in 95.5% of cases. Postoperative cerebrospinal fluid (CSF) leaks were identified in 6 cases.

CONCLUSION

Blood supply to the nasal floor by the dominant inferior meatus branch is more robust than the supply to the anterior LNW by the superficial arterial branch. The LNW flap is the preferred vascularized reconstructive option to the PCF and sella in the absence of a nasoseptal flap (NSF).