Microsurgical anatomy of the distal anterior cerebral artery

Tumor resection in paramedian structures of the frontal lobe poses a risk for corpus callosum infarction

PURPOSE

Surgeons resecting intraparenchymal tumors should be aware of potential white matter ischemia resulting from damage to the medullary artery arising from the cerebral cortex. In the vicinity of the paramedian structure, crucial brain regions for higher brain function such as corpus callosum and cingulate cortex are located. However, the actual area of ischemia induced by damaging the medullary artery supplying the paramedian structures is not known. The present study investigated the ischemic field following tumor resection in paramedian structures of the frontal lobe.

METHODS

Patients having intraparenchymal tumors with lesions in the paramedian structures of the frontal lobe (superior frontal gyrus or cingulate gyrus) resected between April 2016 and June 2022 at Tohoku University Hospital were included in the study. Magnetic resonance images obtained within 72 h after surgery were used to retrospectively examine the extent of the resection and the distribution of ischemic complications. Related postoperative clinical symptoms were assessed using medical records.

RESULTS

Thirty-three cases matched the inclusion criteria. The median age was 48 years. Cases comprised patients with an astrocytoma IDH-mutant (n = 11), oligodendroglioma IDH-mutant, and 1p/19q-codeletion (n = 12), and glioblastoma IDH-wildtype (n = 10). The main locations were superior frontal gyrus only (n = 17), cingulate gyrus only (n = 8), and both the frontal lobe and cingulate gyrus (n = 8). The cingulate gyrus was removed in 19 cases. In 16 of the 19 cases, ischemic foci were observed in the adjacent corpus callosum. In the 14 cases in which the cingulate gyrus was not removed, no ischemic foci appeared in the corpus callosum. Three cases exhibited a prolonged disturbance of consciousness after the second postoperative day, all with corpus callosum infarction.

CONCLUSION

Surgeons resecting intraparenchymal tumors in the paramedian structures of the frontal lobe, especially the cingulate gyrus, should be aware of the potential for ischemia foci emerging in the corpus callosum.

Dual fenestration of the A1 and azygos A2 segments of the anterior cerebral artery illustrated by Magnetic Resonance Imaging

PURPOSE

Fenestrations are probably the most common among the anomalies of intracranial arteries. They are known for their association with other vascular conditions, such as aneurysms and arterio-venous malformations. Anterior cerebral artery (ACA) in both A1 and A2 segments is subjected to many anomalies, including fenestrations, but they are rarer than hypoplasia and aplasia. The association of more than one anomaly has been described, but the presence of a dual fenestration in a single arterial segment has been anecdotally reported.

METHODS

A case of an incidentally discovered association of two ACA anomalies, i.e. dual fenestration in the A1 segment and azygos pattern in the A2 segment, is presented. Both anomalies were identified in a brain Magnetic Resonance Imaging (MRI) study with MR Angiography. The clinical indication for MRI was tinnitus. The other intracranial arteries were unremarkable (apart from duplicated posterior communicating arteries) and the brain parenchyma did not show abnormalities. No aneurysms were found.

CONCLUSIONS

The reported anomalies (the dual fenestration and the azygos A2 ACA) are located in the same arterial territory and potentially have a long-term effect on the local hemodynamics of the ACA facilitating the formation of aneurysms. Then, an imaging follow-up may be adviced.

Anterior communicating aneurysm clipping: How I do it

Up to 40% of intracranial aneurysms arise from the anterior cerebral artery and anterior communicating artery (ACA-ACoA) complex. The vast variability of vessel anomalies and the surrounding critical structures correlate with severe morbidity and mortality rates in case of rupture. In the era of cutting-edge advantages of endovascular procedures, surgical expertise is reducing. This article describes our institutional surgical technique in managing ACoA aneurysms, focusing on anatomical variants, approach selection, and technical intraoperative nuances.

The microsurgical anatomy of the paracentral lobule artery: a cadaveric series

PURPOSE

The paracentral lobule artery (PLA) is a typically present branch of the distal anterior cerebral artery (ACA), irrigating the homonymous lobule. The PLA origin is either a pericallosal portion of the ACA or a prominent branch of the ACA termed callosomarginal (CMA). In addition to the paracentral lobule, the PLA irrigates the cingulate gyrus in the medial hemispheric surface, and the superior portion of the precentral and postcentral gyri in the lateral hemispheric surface. The present cadaveric case series aimed at establishing previously unreported morphometric estimates of the PLA, including its length according to its site of origin, its supplying branches according to its distribution area, as well as its anastomoses.

METHODS

Seventeen colored latex-injected cadaveric heads were studied with a surgical microscope and microsurgical instruments.

RESULTS

The PLA was invariably present and most commonly originated from the A4 (n = 15 hemispheres, 50%) segment of the ACA. Other PLA origins were the CMA (n = 10, 30%), the A3 (n = 5, 16.7%) and the A5 (n = 1, 3.3%) segments. When the PLA originated from the A4, its mean (SD) overall length was 7.6 (17.9) mm and its mean (SD) diameter was 0.88 (0.26) mm. The PLA supplied the paracentral lobule, cingulate gyrus and post central gyrus with a mean (SD) of 28.07 (13.4), 8.53 (4.27), 5.92 (4.4) branches respectively and the precentral gyrus with a median [IQR] of 2 [0-6] branches. The most common anastomoses of the PLA in the medial and the lateral hemispheric surface involved the ipsilateral posterior internal frontal artery and the branches of the middle cerebral artery, respectively. There were no significant differences between sexes or hemispheric sides for the anatomical features of the artery analyzed.

CONCLUSION

The present study established previously unreported morphometric estimates for the PLA by considering all possible PLA variant origins and morphological variants. Given that variable pathologies have been previously detected in the areas supplied by the PLA, a better understanding of its anatomy can aid surgical planning and approaches.

Finding MeVO: Identifying Intracranial Medium-Vessel Occlusions at CT Angiography

The development of methods to detect and treat intracranial large-vessel occlusions (LVOs) has revolutionized the management of acute ischemic stroke. CT angiography (CTA) of the head and neck is effective in depicting LVOs and widely used in the evaluation of patients who have had a stroke. Ongoing efforts are now focused on the potential to detect and treat intracranial medium-vessel occlusions (MeVOs), which by definition are smaller than LVOs and thus more difficult to detect with CTA. The authors review common and variant anatomies of medium-sized cerebral arteries and the appearance of a variety of MeVOs on CT angiograms. Possible pitfalls in MeVO detection include rare anatomic variants, calcified thrombi, and stump occlusions. Current recommendations for performing CTA and ancillary methods that might aid in MeVO detection are discussed. Understanding the relevant anatomy and the variety of appearances of MeVOs aids radiologists in identifying these occlusions, particularly in the setting of urgent stroke. ©RSNA, 2024 See the invited commentary by Ospel and Nguyen in this issue.

Efficacy of endovascular treatment for distal anterior cerebral artery aneurysms: A multicenter observational study

OBJECTIVES

Distal anterior cerebral artery (DACA) aneurysms account for 1%-9% of all intracranial aneurysms. Microsurgical treatment is generally preferred for DACA aneurysms; however, it presents challenges owing to the anatomical complexities. Advances in neuro-interventional techniques have yielded promising results. This study aims to compare the clinical outcomes of DACA aneurysms treated with microsurgery and endovascular treatment (EVT) to elucidate the efficacy of EVT.

MATERIALS AND METHODS

A multicenter observational registry comprising 16 stroke centers was utilized for this study. Data was retrospectively and prospectively analyzed from 166 patients with DACA aneurysms in our database, which included 4,552 consecutive patients with ruptured or unruptured intracranial aneurysms who underwent microsurgical or endovascular treatment between January 2013 and December 2021.

RESULTS

Surgical clipping was performed in 115 patients, and 51 underwent coil embolization. The median follow-up duration was 15.3 months. No significant differences were observed in patient characteristics between the two treatment modalities. There were no differences in complication-related morbidity between the microsurgical treatment and EVT groups in either unruptured (10.5% vs. 9.1%, p=1.00) or ruptured aneurysms (5.2% vs. 6.9%, p=0.66). Coil embolization resulted in higher recurrence and retreatment rates than surgical clipping did, especially for ruptured aneurysms (2.6% vs. 27.6%, p<0.01).

CONCLUSIONS

Endovascular treatment is an alternative to microsurgery for DACA aneurysms especially in unruptured cases or the patients who have difficulty undergoing craniotomy due to their general condition, albeit with considerations for higher recurrence and retreatment rates, particularly in ruptured cases. Close follow-up is crucial for the effective management of these challenges. Further studies are needed to refine the treatment strategies for DACA aneurysms.

Prevalence of ACA variations: A systematic review and meta‑analysis

The anterior cerebral artery (ACA) and its divisions enclose symptomatically critical and supplementary differentiations. Anatomical variations of the distal ACA that are irregularly detected can be separated into three major groups, namely, azygos, bihemispheric and median ACA variations. The present study performed a systematic review and meta-analysis. The PICOS criteria and electronic databases, namely the Cochrane Library, PubMed (until December, 2023), Embase (until December, 2023) and MEDLINE (until December, 2023) were used to identify 48 articles to fulfill the eligible criteria. As a limited number of studies exist on the prevalence of ACA anatomical variations, the present meta-analysis aimed to determine the precise incidence of these variants. In addition, with the comparative description between cadaveric (autopsy) and imaging cases, more accurate results were extract from the prevalence presentation of the distal ACA variants. On the whole, no statistically significant differences were found between autopsy and imaging studies.

Comprehensive analysis of the rostral and caudal cerebral artery branching patterns in the dromedary camel (Camelus dromedarius)

Introduction

In mammals, the cerebral cortex depends on a robust blood supply for optimal function. The rostral and caudal cerebral arteries are critical for supplying the cerebrum. This study presents the first detailed anatomical description of the rostral and caudal cerebral arteries of dromedary camels (Camelus dromedarius), including their origins, routes, and complex branching patterns.

Methods

A sample of 55 heads from male dromedary camels aged 2-6 years was analyzed using advanced casting techniques with various casting materials to provide precise visualization of these arterial structures.

Results

The rostral cerebral arteries originate dorsally from the rostral epidural rete mirabile (RERM), while the caudal cerebral arteries arise from the caudal communicating artery, which is another branch of the RERM. Both sets of arteries give rise to multiple cortical branches responsible for supplying the medial aspects of the frontal, parietal, and temporal lobes, as well as the medial and caudal regions of the occipital lobes.

Conclusion

This study significantly expands our understanding of the cerebrovascular anatomy of dromedary camels. Our findings have potential implications for veterinary medicine in the diagnosis and treatment of neurological disorders in camels and may offer insights into broader comparative neuroscience research.

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.

The Management of Persistent Distal Occlusions after Mechanical Thrombectomy and Thrombolysis: An Inter- and Intrarater Agreement Study

BACKGROUND AND PURPOSE

The best management of patients with persistent distal occlusion after mechanical thrombectomy with or without IV thrombolysis remains unknown. We sought to evaluate the variability and agreement in decision-making for persistent distal occlusions.

MATERIALS AND METHODS

A portfolio of 60 cases was sent to clinicians with varying backgrounds and experience. Responders were asked whether they considered conservative management or rescue therapy (stent retriever, aspiration, or intra-arterial thrombolytics) a treatment option as well as their willingness to enroll patients in a randomized trial. Agreement was assessed using κ statistics.

RESULTS

The electronic survey was answered by 31 physicians (8 vascular neurologists and 23 interventional neuroradiologists). Decisions for rescue therapies were more frequent (n = 1116/1860, 60%) than for conservative management (n = 744/1860, 40%; P < .001). Interrater agreement regarding the final management decision was "slight" (κ = 0.12; 95% CI, 0.09-0.14) and did not improve when subgroups of clinicians were studied according to background, experience, and specialty or when cases were grouped according to the level of occlusion. On delayed re-questioning, 23 of 29 respondents (79.3%) disagreed with themselves on at least 20% of cases. Respondents were willing to offer trial participation in 1295 of 1860 (69.6%) cases.

CONCLUSIONS

Individuals did not agree regarding the best management of patients with persistent distal occlusion after mechanical thrombectomy and IV thrombolysis. There is sufficient uncertainty to justify a dedicated randomized trial.

The Anatomical Variation of the Distal Anterior Cerebral Artery: An Angiographic Study in a Greek Population Sample

Objective The current retrospective angiographic study establishes the rates of variants in the distal anterior cerebral artery (DACA) in a sample of the Greek population. Methods Data were collected from 456 patients who underwent two-dimensional (2D) or three-dimensional (3D) digital subtraction angiography (DSA) of the carotid and vertebral arteries bilaterally. The study focused on patients with good visualization of the anterior and posterior circulations and employed magnetic resonance (MR) or computed tomography (CT) angiography for 3D reconstruction. The anterior cerebral artery (ACA) was classified into one of its two basic configurations, that is, with or without the callosomarginal artery (CMA). The bihemispheric, median, and azygos ACA patterns were also identified. Results The majority (373/456, 81.8%) exhibited a typical DACA pattern. The bihemispheric, median, and azygos patterns were identified in 66/456 (14.5%), 10/456 (2.2%), and 7/456 (1.5%), respectively. The CMA was present in 824/912 (90.4%) of the hemispheres, with a trend toward male predominance for bilateral presence (males: 167/192, 86.98%; females: 210/264, 79.55%; p = 0.05). In particular, the CMA was present significantly more frequently (p = 0.002) in the left hemispheres of male patients. Gender differences in CMA presence persisted in the analysis of the patients with a typical DACA pattern. Conclusion This study provides insights into the variations of the DACA in the Greek population. The observed gender differences in CMA rates suggest potential morphological variations in cerebral vasculature between males and females and contribute to a better understanding of vascular anatomy for clinical and surgical applications.

The Anterior Interhemispheric Transcallosal Approach to the Ventricles: How We Do It

Intraventricular tumors of the lateral and third ventricles are relatively rare, accounting for 1-2% of all primary brain tumors in most large series [1-4]. They can be uniquely challenging to approach due to their deep location, propensity to become large before they are discovered, and association with hydrocephalus [5, 6]. The surgeon's goal is to develop a route to these deep lesions that will cause the least morbidity, provide adequate working space, and achieve a complete resection. This must be performed with minimal manipulation of the neural structures encircling the ventricles, avoiding functional cortical areas, and acquiring early control of feeding vessels [7, 8].

Ruptured Aneurysm at the Origin of an Anomalous Callosomarginal Artery Arising from the A1 Segment of the Anterior Cerebral Artery -A Case Report-

Aneurysms of the A1 segment of the anterior cerebral artery tend to develop in combination with various vascular anomalies of the A1 segment. Arterial branches that originate from the A1 segment and perfuse cortical regions are known to be rare. In this report, we describe a 48-year-old woman who presented with a ruptured aneurysm at the origin of an anomalous cortical artery arising from the A1 segment, for which microsurgical neck clipping was performed. Intraoperatively, the anomalous artery was seen to originate from the A1 segment, running into the interhemispheric fissure. An aneurysm was located at the bifurcation of the anomalous artery and the A1 segment. Postoperative angiography showed that the anomalous artery has branched into the fronto-orbital artery and the frontopolar artery and terminated as the anterior internal frontal arteries. We report a rare case of an aneurysm arising from an anomalous callosomarginal artery that arose from the A1 segment and perfused the cortical region. It is of significance to recognize that an aneurysm can develop at the origin of an anomalous artery that arises from the A1 segment.

Embryology of the anterior communicating artery complex: implications on possible adult variants

The anterior cerebral artery (ACA) and the anterior communicating artery (AComA) are important arteries of the telencephalon and are prominent location for cerebral aneurysms. Their embryological development is closely linked, and explains the possible variants seen in adults. In this paper, we present details related to the development of these two arteries, focusing on some variants such as the infra-optic course of the ACA, the unpaired ACA, and the persistent primitive olfactory artery.

A distal anterior cerebral artery tripod branching to a bihemispheric pericallosal artery

The anterior cerebral artery (ACA) branching pattern may be particularly complex and variant including bifurcations, trifurcations or quadrifurcations, thus leading to typical or atypical vessels. The bihemispheric ACA (BhACA) variant crosses the midline to supply the contralateral hemisphere. The current case highlights a left-sided ACA trifurcation into a bihemispheric pericallosal artery, and two ipsilateral atypical arteries: a callosomarginal artery of short course and a left-sided pericallosal artery of an aberrant course into the cingulate sulcus. The depicted trifurcation was characterized as a distal ACA tripod. The bihemispheric branch supplied the contralateral pericallosal area and coursed into the cingulate sulcus. Deviations from the typical ACA pattern, especially when they coexist are quite rare and may complicate neurosurgical approaches or raise diagnostic difficulties. The BhACA may be implicated in aneurysm formation and bilateral ischemia after its occlusion. Knowledge of such variants, as well as awareness of the complications they may be related to, is of great significance.

Anatomical structures, cell types and biomarkers of the Human Reference Atlas

The Human Reference Atlas (HRA) aims to map all of the cells of the human body to advance biomedical research and clinical practice. This Perspective presents collaborative work by members of 16 international consortia on two essential and interlinked parts of the HRA: (1) three-dimensional representations of anatomy that are linked to (2) tables that name and interlink major anatomical structures, cell types, plus biomarkers (ASCT+B). We discuss four examples that demonstrate the practical utility of the HRA.

Endovascular Device Choice and Tools for Recanalization of Medium Vessel Occlusions: Insights From the MeVO FRONTIERS International Survey

Background: Endovascular treatment (EVT) for stroke due to medium vessel occlusion (MeVO) can be technically challenging. Devices and tools are rapidly evolving. We aimed to gain insight into preferences and global perspectives on the usage of endovascular tools in treating MeVOs.

Methods: We conducted an international survey with seven scenarios of patients presenting A3, M2/3, M3, M3/4, or P2/3 occlusions. Respondents were asked for their preferred first-line endovascular approach, and whether they felt that the appropriate endovascular tools were available to them. Answers were analyzed by occlusion location and geographical region of practice, using multinomial/binary logistic regression.

Results: A total of 263 neurointerventionists provided 1836 responses. The first-line preferences of physicians were evenly distributed among stent-retrievers, combined approaches, and aspiration only (33.2, 29.8, and 26.8%, respectively). A3 occlusions were more often treated with stent-retrievers (RR 1.21, 95% CI: 1.07–1.36), while intra-arterial thrombolysis was more often preferred in M3 (RR 2.47, 95% CI: 1.53–3.98) and M3/4 occlusions (RR 7.71, 95% CI: 4.16–14.28) compared to M2/3 occlusions. Respondents who thought appropriate tools are currently not available more often chose stent retrievers alone (RR 2.07; 95% CI: 1.01–4.24) or intra-arterial thrombolysis (RR 3.35, 95% CI: 1.26–8.42). Physicians who stated that they do not have access to optimal tools opted more often not to treat at all (RR 3.41, 95% CI: 1.11–10.49). Stent-retrievers alone were chosen more often and contact aspiration alone less often as a first-line approach in Europe (RR 2.12, 95% CI: 1.38–3.24; and RR 0.49, 95% CI 0.34–0.70, respectively) compared to the United States and Canada.

Conclusions: In EVT for MeVO strokes, neurointerventionalists choose a targeted vessel specific first-line approach depending on the occlusion location, region of practice, and availability of the appropriate tools.

Retractorless combined pterional and interhemispheric approach to achieve proximal control in pericallosal artery aneurysm: how I do it

BACKGROUND

Pericallosal artery aneurysms differ from other cerebral aneurysms for the difficulty in establishing proximal vascular control during surgical clipping. A frontomedial craniotomy with combined pterional and interhemispheric approach allows obtaining a better proximal control.

MATERIALS AND METHODS

We present our surgical technique to achieve a proximal vessel control in pericallosal artery aneurysm clipping using a combined pterional and interhemispheric approach through frontomedial craniotomy. This surgical technique is illustrated by an intraoperative video.

CONCLUSION

Proximal control for pericallosal artery aneurysm clipping can be challenging. In selected cases, a single craniotomy allows performing two approaches and obtaining a safer proximal control for surgical clipping.

Endovascular treatment of anterior cerebral artery occlusions

There are limited data on endovascular treatment (EVT) for anterior cerebral artery (ACA) occlusions. This review focuses on aspects related to ACA EVT: ACA anatomy, clinical and imaging findings, prognosis of ACA stroke, and ACA thrombectomy techniques. The ACA anatomy, and the regions supplied by the ACA, are highly variable; frequent anatomical variants include azygos ACA, triplicated ACA and fenestrations of the anterior communicating artery. ACA occlusions can be classified based on occlusion location, their continuity with other vessel occlusions (isolated ACA occlusion vs ACA occlusion as part of a carotid T occlusion) and etiology (primary-spontaneous ACA occlusion, vs secondary-spontaneous or iatrogenic due to clot fragmentation/migration). Symptoms of ACA stroke differ in severity and nature due to large inter-individual variations in territorial ACA blood supply. Generally, ACA strokes are severely disabling, and the typical clinical hallmark is a motor deficit of the contralateral lower extremity. Advanced imaging (CT perfusion, multiphase CT angiography) increases the likelihood of the correct diagnosis of ACA stroke and should be obtained on routine basis.Available data for ACA EVT suggest its feasibility and safety while clinical outcomes are often unfavorable with conservative management. Therefore, the potential benefit of EVT seems obvious. An optimized endovascular approach for ACA thrombectomy comprises the development and use of smaller and softer devices that can be delivered through small microcatheters with an optimized vector of force. Ultimately, generating high-level evidence for ACA EVT from randomized trials remains warranted.

Tailored Communicating Bypass for the Management of Complex Anterior Communicating Artery Aneurysms: "Flow-Counteraction" In Situ Bypass and Interposition Bypass Using Contralateral A2 Orifice as Donor Site

BACKGROUND

The use of bypass surgery for anterior communicating artery (ACOM) aneurysms is technically challenging. Communicating bypass (COMB), such as pericallosal artery side-to-side anastomosis, is the most frequently used and anatomically directed reconstruction option. However, in many complex cases, this technique may not afford a sufficient blood supply or necessitate sacrificing the ACOM and the eloquent perforators arising from it.

OBJECTIVE

To evaluate tailored COMB and propose a practical algorithm for the management of complex ACOM aneurysms.

METHODS

For 1 patient with an aneurysm incorporating the entire ACOM, conventional in Situ A3-A3 bypass was performed as the sole treatment in order to create competing flow for aneurysm obliteration, sparing the sacrifice of eloquent perforators. In situations in which A2s were asymmetric in the other case, the contralateral A2 orifice was selected as the donor site to provide adequate blood flow by employing a short segment of the interposition graft.

RESULTS

The aneurysm was not visualized in patients with in Situ A3-A3 bypass because of the "flow-counteraction" strategy. The second patient, who underwent implementation of the contralateral A2 orifice for ipsilateral A3 interposition bypass, demonstrated sufficient bypass patency and complete obliteration of the aneurysm.

CONCLUSION

The feasibility of conventional COMB combined with complete trapping may only be constrained to selected ideal cases for the treatment of complex ACOM aneurysms. Innovative modifications should be designed in order to create individualized strategies for each patient because of the complexity of hemodynamics and the vascular architecture. Flow-counteraction in Situ bypass and interposition bypass using the contralateral A2 orifice as the donor site are 2 novel modalities for optimizing the advantages and broadening the applications of COMB for the treatment of complex ACOM aneurysms.

In Situ Side-to-Side Pericallosal-Pericallosal Artery and Callosomarginal-Callosomarginal Artery Bypasses for Complex Distal Anterior Cerebral Artery Aneurysms: A Technical Note

BACKGROUND

Despite surgical and endovascular technical improvements over the last decades, the treatment of complex aneurysms of the distal anterior cerebral artery (ACA) is very challenging for both vascular neurosurgeons and interventional neuroradiologists. Furthermore, the interpersonal anatomic variability requires, most of the time, a tailored planning.

OBJECTIVE

To describe a novel technique of bypasses in the territory of ACA to protect the brain territory distal to the aneurysm.

METHODS

A 53-yr-old male with a large complex fusiform aneurysm of the left distal A2 segment of the ACA, involving the origin of the callosomarginal and pericallosal arteries, was judged not suitable for a single procedure (endovascular or neurosurgical). Two side-to-side bypasses were performed in a single surgery to connect the pericallosal and callosomarginal arteries of both sides, distally to the aneurysm. Subsequently, an endovascular embolization of the aneurysm was achieved with coils.

RESULTS

The patency of the microanastomoses, performed in the anterior interhemispheric fissure, was positively evaluated intraoperatively with indocyanine green and fluorescein videoangiography. The aneurysm sac, together with proximal A2 segment, was completely occluded with platinum coils. At the last follow-up, computed tomography angiography confirmed the patency of both bypasses, without any sign of aneurysm recanalization. The patients never complained of any focal neurological deficits or worsening of clinical status.

CONCLUSION

We present an elegant and innovative solution to completely protect the distal ACA territory in cases of complex aneurysm involving the origin of both callosomarginal and pericallosal arteries.

Clinical prognosis of isolated anterior cerebral artery territory infarction: a retrospective study

Background

Isolated anterior cerebral artery territory (ACA) infarction is a rare phenomenon, and is known to have distinctive clinical features. Little is known regarding the clinical prognosis of isolated ACA territory infarction with associated factors, and its impact on dwelling and job status. We investigated the short- and long-term outcomes of anterior cerebral artery (ACA) territory infarction, and the associated factors involved in the development of the distinctive symptoms.

Methods

This retrospective study in a prospective cohort of acute ischaemic stroke patients included consecutively enrolled patients with isolated ACA territory infarction. We investigated the functional status using the modified Rankin scale (mRS) score at discharge, three months’ post-discharge, and one-year post-discharge. We also investigated the occlusion site of the ACA (proximal vs. distal); presence of distinctive symptoms of ACA territory infarction including behaviour changes, indifference, aphasia, and urinary incontinence; and the effect of these symptoms on dwelling and job status one year after discharge.

Results

Between April 2014 and March 2019, 47 patients with isolated ACA territory infarction were included. Twenty-nine patients (61.7 %) had good outcomes (mRS ≤ 2) at discharge; however, the mRS score increased at three months (40; 85.1 %, p < 0.001) and one year (41; 87.2 %) post-discharge. Occlusion of the ACA proximal segment was independently associated with the development of distinctive symptoms (adjusted odds ratio, 17.68; 95 % confidence interval: 2.55–122.56, p < 0.05). Twenty-one (48.8 %) patients with good outcomes at one year experienced a change in dwelling status and job loss; 20 (95.2 %) of them had distinctive ACA territory symptoms with proximal ACA occlusion.

Conclusions

Short- and long-term outcomes of isolated ACA territory infarction were favourable. However, proximal segment occlusion was associated with the development of distinctive symptoms, possibly related to future dwelling and job status.

Traumatic rupture of the circle of Willis with closed head injury: Its pathology and possible pathogenesis

Massive and fatal subarachnoid hemorrhage (SAH) with an injury on the circle of Willis may be caused by blunt force to the head; however, it is extremely rare, and the precise mechanism of arterial rupture remains unclear. We investigated the clinicopathologic appearance of four rare autopsy cases of massive SAH associated with the rupture of the circle of Willis. All four cases were men aged 17-75 years who presented with a loss of consciousness within a short interval after the injury. Autopsy revealed that the rupture site was located in the vertebral artery in two cases and in the anterior cerebral artery (ACA) in two cases. During our literature review, we found no previous report on traumatic ACA rupture. Based on the correlation of the autopsy findings and the circumstance of injury, we determined that the accidental excessive stretching of the selected artery by neck anteflexion or rotation after a blunt trauma to the posterior head might have caused this rare lethal injury. These cases demonstrated the diversity of the traumatic rupture site of the circle of Willis after a blunt head and/or neck injury. The topographical features of the circle of Willis, particularly in correlation with the surrounding tissue, might account for the occurrence and site of these rare injuries.

Lamina terminalis fenestration: An important neurosurgical corridor

Cerebrospinal fluid (CSF) disorders are challenging conditions in neurosurgical practice. The majority of CSF is contained in the basal cisterns of the brain, which are subarachnoid compartments that communicate with each other, and contribute to the circulation of CSF. Yaşargil et al. (1976) was the first to provide the systematic classification and naming of the basal cisterns. The lamina terminalis (LT) starts from the gyrus rectus and descends to the lateral aspect of the optic chiasm. It is a thick arachnoidal membrane delineating the anterior wall of the third ventricle that borders the LT cistern. With the introduction of the operating microscope and the progressive development of modern neurosurgery, the arachnoid and basal cisterns have been used as surgical corridors in order to reach deep areas of the brain and to release CSF for brain relaxation. In this way, the LT is used as a surgical corridor for the treatment of several conditions such as obstructive hydrocephalus and diencephalic tumors. In this chapter, we will describe the anatomy of the LT, possible conditions treated by opening the LT, the different surgical approaches to opening the LT, along with their advantages and disadvantages.

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

BACKGROUND

The endoscopic endonasal approach is a surgical alternative for midline anterior skull base tumors. A detailed understanding of the proximal anterior cerebral artery (ACA) branches' anatomy from an endonasal perspective is essential for avoiding vascular complications.

OBJECTIVE

To evaluate, from an endonasal perspective, the anatomic variations of the ACA and its proximal branches, specifically the recurrent artery of Heubner (RAH), and the fronto-orbital (FOA) and frontopolar (FPA) arteries.

METHODS

We study the origin, course, branching pattern, diameter, and relationship between the proximal ACA branches and the optic apparatus and olfactory tract in 25 head specimens.

RESULTS

The RAH was present in all hemispheres and originated within 3 ± 1.5 mm of the AcomA, with a 0.4 ± 0.1 mm diameter. Based on its relationship with the A1 segment, we observed three RAH courses: anterior (40%), superior (22%), and posterior (38%). The FOA was present in all cases, a mean of 6 ± 4 mm from the AcomA, with a 0.7 ± 0.4 mm diameter. The FOA arose mainly from the A2 (70%), with three courses in relation to the olfactory tract: crossing its proximal third (54%), crossing its middle third (31%), and running parallel to it along the gyrus rectus (15%). The FPA was present in 92% of the hemispheres, a mean of 10 ± 5 mm from the AcomA, always arising from the A2 and coursing anteriorly within the interhemispheric fissure towards the frontal pole.

CONCLUSION

The RAH, FOA, and FPA can be differentiated by origin, course, and destination using the A1 segment, olfactory tract, and interhemispheric fissure, respectively, as surgical landmarks.

Selective Brain Hypothermia for Ischemic MCA-M1 Stroke: Influence of Cerebral Arterial Circulation in a 3D Brain Temperature Model

Acute ischemic stroke is a major health problem with a high mortality rate and a high risk for permanent disabilities. Selective brain hypothermia has the neuroprotective potential to possibly lower cerebral harm. A recently developed catheter system enables to combine endovascular blood cooling and thrombectomy using the same endovascular access. By using the penumbral perfusion via leptomeningeal collaterals, the catheter aims at enabling a cold reperfusion, which mitigates the risk of a reperfusion injury. However, cerebral circulation is highly patient-specific and can vary greatly. Since direct measurement of remaining perfusion and temperature decrease induced by the catheter is not possible without additional harm to the patient, computational modeling provides an alternative to gain knowledge about resulting cerebral temperature decrease. In this work, we present a brain temperature model with a realistic division into gray and white matter and consideration of spatially resolved perfusion. Furthermore, it includes detailed anatomy of cerebral circulation with possibility of personalizing on base of real patient anatomy. For evaluation of catheter performance in terms of cold reperfusion and to analyze its general performance, we calculated the decrease in brain temperature in case of a large vessel occlusion in the middle cerebral artery (MCA) for different scenarios of cerebral arterial anatomy. Congenital arterial variations in the circle of Willis had a distinct influence on the cooling effect and the resulting spatial temperature distribution before vessel recanalization. Independent of the branching configurations, the model predicted a cold reperfusion due to a strong temperature decrease after recanalization (1.4-2.2  ^°C after 25 min of cooling, recanalization after 20 min of cooling). Our model illustrates the effectiveness of endovascular cooling in combination with mechanical thrombectomy and its results serve as an adequate substitute for temperature measurement in a clinical setting in the absence of direct intraparenchymal temperature probes.

Morphometric evaluation of Anterior Cerebral Artery (on Digital Subtraction Angiography)-Potential implications

PURPOSE

The aim of the present study was to perform a morphometric analysis of ACA and to establish significant differences, if any, with sex and age via Digital Subtraction Angiography (DSA).

METHODS

This cross-sectional study was conducted on 70 patients (>20 years) for the evaluation of ACA by Digital Subtraction Angiography done on a Philips biplane system clarity (Allura FD20/20). Length and diameter of ACA were taken manually on the DSA console using auto-calibration. Statistical analysis was done.

RESULT

Mean diameter and length of ACA was found to be greater in female. The f-ratio value for diameter and length of the same was 1.43 and 0.92 respectively. The length of ACA was found to be statistically significant for different age groups. The mean length of ACA followed a decreasing trend with age, whereas mean diameter of ACA was nearly the same in all the age groups.

CONCLUSION

The results of our study show that the length of ACA was found to be statistically significant for different age groups.

Different strategies in the management of thalamic space-occupying lesions

Introduction

Thalamic space-occupying lesions (SOL) are considered challenging for microsurgical removal. Unfortunately, the pathological features of lesions occurring in the thalamic region are different with a wide variation in clinical behavior and outcome. Although microsurgery is still the gold standard in the management of these lesions through different approaches, questions remain whether surgery is feasible and safe in these patients and what are the alternatives? It is well known that stereotactic techniques may be favorable especially in cystic, small, multiple lesions and in combination with adjuvant therapy. Transventricular endoscopic approach is also an alternative technique to combine tumor biopsy and treatment of hydrocephalus.

Aim of the study

The identification of the different procedures for the management of thalamic SOL in respect to the age of the patient, the clinical condition, and the site of the lesion as well as its extent and pathology.

Patients and methods

This prospective study included 35 patients having thalamic lesions with a mean age of 27 years old who were treated with different approaches including microsurgical, stereotactic, and endoscopic approaches. The clinical outcome was assessed as the same, improved, deteriorated, or died in comparison to the initial clinical status, while the radiological control was measured as no gross residual, residual < 10% and residual > 10%. Chi-square test was used to test the association between two categorical variables.

Results

Thirty-five patients were included in this study, 20 were males and 15 were females. Eight cases were children, and 27 cases were adults. The most common clinical presentation was contralateral hemiparesis. The most common pathology was pilocytic astrocytoma. Radiological studies showed that the total thalamic type was the most common topographic variant and that 10 cases had hydrocephalus treated with CSF diversion procedures. For the definitive lesion, 2 cases underwent endoscopic biopsy and cystoventriculostomy and 18 cases had stereotactic technique in the form of biopsy, aspiration, and ommaya reservoir application, while 15 cases had microsurgery through different approaches with stereotactic technique preceding surgery in 2 of them.

Conclusion

The main factors involved in choosing the appropriate approach included nature of the lesion (solid or cystic, multiplicity), suspected pathological type, and diffusion tensor imaging. Abscesses are best treated with stereotaxy, while non-neoplastic cystic lesions (other than abscesses) related to the ventricles are best treated with endoscopy. For the remaining pathologies, maximum surgical removal is the best management. Best lesion control was provided by microsurgery.

Trial registration

ISRCTN 1380 registered 6/11/2018

Vascularization of the Alouatta belzebul brain base

ABSTRACT: We studied the arterial circle in the brain of five specimens of the Alouatta belzebul primate. The material had the arterial system perfused (water at 40°C), injected with stained latex (Neoprene 650), fixed in aqueous formaldehyde solution (10%) and dissected for vessel verification. The arterial circle of this primate is composed of two vascular systems: the vertebra-basilar and the carotid ones, which anastomose to close the arterial circuit. In the caudal portion of the arterial circle, there are the vertebral arteries and their branches: the rostral spinal artery and the caudal inferior cerebellar artery. The anastomosis of the vertebral arteries gives rise to the basilar artery. It presented an anatomical variation at the beginning of its path, forming a double basilar artery, called arterial island. In its course, it emitted branches giving rise to the rostral inferior cerebellar artery, the pontine arteries, the rostral cerebellar arteries, the satellite rostral cerebellar arteries and its terminal branch, the caudal cerebral artery, which presented itself in two segments: the pre-communicating one and post-communicating, joining the internal carotid artery and originating the caudal communicating artery. This group of arteries and anastomoses enclose the caudal portion of the arterial circle. From the right and left internal carotid arteries begins the rostral portion of the arterial circle, which consists of the right and left rostral cerebral arteries and the right and left middle cerebral arteries. The rostral cerebral arteries anastomose into a single trunk, giving rise to the interhemispheric artery, and in A. belzebul and Sapajus libidinosus, the rostral communicating artery is absent. The interhemispheric artery goes to the midbrain region and the corpus callosum knee divides into pericalous artery and callosarginal artery, which will supply the pre and post-central regions of the cerebral hemispheres of this species, as well as other non-human and human primates. It is noted that in the first part of the left rostral cerebral artery, there is a direct inosculation between the recurrent branch of the rostral cerebral artery and left middle cerebral artery to supply the entorhinal region. This fact also occurs in Pongo spp. The middle cerebral artery travels along the lateral sulcus where it emits several superficial branches to irrigate the superior and inferior lateral cortical regions of the frontal, parietal and temporal lobes. It is not part of the arterial circle but is the terminal branch of the internal carotid artery. A. belzebul can be considered to depend on two sources of supply to the brain: the vertebra-basilar and carotid systems, contributing to the intervention of veterinarians during clinical and surgical procedures in other primates, as well as the preservation of wild animals.

Radiological and clinical outcomes of endovascular coiling of proximal A1 aneurysms

Aneurysms of the proximal anterior cerebral artery (A1) are rare. Of these A1 aneurysms, proximal A1 aneurysms are among the most challenging for endovascular coiling. This study aimed to evaluate the angiographic features and radiological and clinical outcomes of endovascular coiling of proximal A1 aneurysms. We recruited 38 patients with 38 proximal A1 aneurysms treated with endovascular coiling between September 2005 and April 2016. Baseline patient characteristics, aneurysm morphology, endovascular treatment techniques, immediate post-procedural radiological outcome, and follow-up clinical and radiological outcomes were evaluated, as were risk factors for recurrence. Sixteen proximal A1 aneurysms ruptured (42.1%). Six procedural complications (15.8%), including 5 thromboembolisms and 1 coil migration, were noted. There was no procedural morbidity or mortality. Immediate post-procedural radiological outcomes showed complete occlusion in 23, residual necks in 12, and residual sacs in 3 lesions. Follow-up angiographic outcomes were possible for 28 lesions (73.7%). Follow-up angiography showed sac recurrence in 3 (10.7%) and neck recurrence in 3 (10.7%) lesions. Retreatment was performed in 4 lesions (14.3%); all were treated by endovascular coiling. The presence of aneurysmal ruptures was only significant regarding recurrence in univariate logistic regression analysis. In our study, endovascular coiling of proximal A1 aneurysms was associated with a relatively high rate of procedural complications but not with procedural morbidity and mortality. The recurrence and retreatment rates of endovascular coiling of proximal A1 aneurysms were relatively high, and presence of rupture was significant for recurrence.

Anterior Cerebral Artery: Variant Anatomy and Pathology

The anterior cerebral artery (ACA) contains anatomical variants that are closely related to its embryology and development. In this study, the authors reviewed the most commonly encountered variants of the ACA and anterior communicating artery. They also reviewed the embryological origins of these variants as well as a variety of associated pathologies. Several variants are described and highlighted with illustrations including: (1) the aberrant origin of the ACA from the internal carotid artery and its developmental association with the ophthalmic artery; (2) the persistent olfactory artery; (3) the azygous ACA; (4) the triplicated ACA; and (5) multiple anterior communicating arteries. The formation of aneurysms is associated with such variants, thus their knowledge and the embryology behind their development are crucial to prevent injury to the patient.

The microneurosurgical anatomy legacy of Albert L. Rhoton Jr., MD: an analysis of transition and evolution over 50 years

The authors chronologically categorized the 160 original articles written by Dr. Rhoton and his fellows to show why they selected their themes and how they carried out their projects. The authors note that as neurosurgery progresses and new techniques and approaches are developed, accurate and safe treatment will depend upon continued clarification of microsurgical anatomy.

Endovascular Therapy in Ischemic Stroke With Acute Large-Vessel Occlusion: Recovery by Endovascular Salvage for Cerebral Ultra-Acute Embolism Japan Registry 2

BACKGROUND

Endovascular therapy has been shown to be effective in patients with acute cerebral large-vessel occlusion, but real-world efficacies are unknown.

METHODS AND RESULTS

We conducted a prospective registry at 46 centers between October 2014 and January 2017. Eligible patients were those who were aged 20 years or older, with acute cerebral large-vessel occlusion, and who were hospitalized within 24 hours of the onset. We enrolled both consecutive patients who were treated with or without endovascular therapy. Endovascular therapy included thrombectomy, balloon angioplasty, stenting, local fibrinolysis, and piercing. The primary outcome was a favorable outcome as defined by a modified Rankin Scale of 0 to 2 at 90 days after onset. Secondary outcomes were modified Rankin Scale of 0 to 1 and mortality. Safety outcomes were intracerebral hemorrhage or a recurrence of ischemic stroke. We constructed the 2242 (1121 each) propensity score-matched patients cohort based on a propensity score for endovascular therapy and estimated the adjusted odds ratio, followed by sensitivity analyses on original 2399 (1278 in endovascular therapy versus 1121 in no endovascular therapy) patients. In the propensity score-matched cohort, favorable outcomes were observed in 35.3% and 30.7% of patients in the endovascular therapy and no endovascular therapy groups, respectively (P=0.02). The adjusted odds ratio for the favorable outcome was 1.44 (95% confidence interval, 1.10-1.86, P=0.007). The efficacy of endovascular therapy in achieving favorable outcomes did not differ between our subgroups and in the sensitivity analyses.

CONCLUSIONS

Endovascular therapy decreased disabilities at 90 days in real-world patients with acute cerebral large-vessel occlusion.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT02419794.

Treatment of Distal Anterior Cerebral Artery Aneurysms with Flow-Diverter Stents: A Single-Center Experience

BACKGROUND AND PURPOSE

Flow diversion for aneurysms beyond the circle of Willis is still debated. Our aim was to evaluate the safety and efficacy of flow diversion treatment of distal anterior cerebral artery aneurysms.

MATERIALS AND METHODS

Consecutive patients with distal anterior cerebral artery aneurysms treated from January 2014 to October 2017 were evaluated retrospectively with prospectively maintained data. Treatment was performed only for unruptured or recanalized aneurysms after coiling. Technical feasibility, procedural complications, aneurysm occlusion (O'Kelly-Marotta grading scale), and clinical outcome were evaluated.

RESULTS

Fifteen patients were included in the study, with 17 distal anterior cerebral artery saccular aneurysms treated with flow-diverter stents. Mean aneurysm size was 4.25 ± 3.9 mm; range, 2-9 mm. Flow diversion was used as retreatment among 6 previously coiled aneurysms (5 ruptured and coiled in the acute phase, and 1 unruptured and recanalized). Stent deployment was technically successful in all cases. During the perioperative period, 1 patient experienced a transient minor stroke (6%), whereas 2 patients reported acute in-stent thrombosis with disabling ischemic complications (13%). Fourteen patients and 16 aneurysms were available during a mean radiologic follow-up of 12 months (range, 3-24 months). Overall, 12 (75%) aneurysms were completely occluded (O'Kelly-Marotta grading scale score D), 1 aneurysm (6%) showed near-complete occlusion (O'Kelly-Marotta grading scale score C), and 3 aneurysms (19%) were incompletely occluded (O'Kelly-Marotta grading scale, score B). All 6 aneurysms previously coiled were completely occluded after flow diversion, whereas 70% of aneurysms treated with flow diverters alone showed complete/near-complete occlusion (O'Kelly-Marotta grading scale C-D). There were no cases of aneurysm rupture, in-stent occlusion, or retreatment during long-term follow-up.

CONCLUSIONS

Treatment of distal anterior cerebral artery aneurysms with flow-diverter stents is feasible and effective, with high rates of aneurysm occlusion. Flow diversion plus coiling, in the retreatment of lesions previously coiled, allowed higher rates of occlusion compared with flow diverters alone. However, the risk of ischemic complications is not negligible, and flow-diversion treatment should be evaluated only for aneurysms not amenable to simple coil embolization.

Subarachnoid Aneurysmal Hemorrhage Associated with Coarctation of the Aorta: Case Report and Review of the Literature

Intracranial aneurysms (IAs) that undergo rupture causing subarachnoid hemorrhage (SAH), are common in young patients with coarctation of the aorta (CoA), but rarer in middle-aged and elderly patients. The pathogenesis of IAs associated with CoA remains unclear. We report the case of a 50-year-old woman who presented with SAH. On evaluation, six IAs were distributed among the anterior communicating artery (ACoA) (ruptured), distal segments of both anterior cerebral arteries (ACA), the left internal carotid artery (ICA), the bifurcation of the left middle cerebral artery (MCA)/MCA early branch, and the inferior trunk of the left MCA. CoA was also diagnosed. The ruptured ACoA IA, and two other unruptured IAs, were successfully clipped during emergency surgery. Postoperative intensive care was instituted to avoid cerebral vasospasm and renal or spinal cord ischemia. During the same hospitalization, the remaining three IAs were clipped at a second surgery. She was discharged with slight cognitive impairment eighty days after admission. Subsequently, she underwent elective treatment for the CoA. According to the literature, IAs associated with CoA have a higher tendency to involve the ACoA than IAs without CoA. Moreover, adult CoA patients tend to have multiple IAs, considered to be due to hypertension associated with CoA, as well as genetic predisposition. In CoA patients, ruptured IAs should be treated as early as possible before correction of the CoA. Close postoperative observation with management of cerebral vasospasm, renal or spinal cord ischemia, and respiratory compromise in the perioperative period is vital.

The cerebral circulation and cerebrovascular disease I: Anatomy

In this paper, which is the first in a three-part series that reviews cerebrovascular anatomy, pathogenesis, and stroke, we lay the anatomical foundation for the rest of the series. Beginning with its origin in the branches of the aorta, we start by describing the arterial system. This system is partitioned into two major divisions (anterior and posterior circulations) that differ significantly in features and pathogenic potential. The systems, and the major branches that comprise them, are described. Description of the arterial system proceeds to the point of the fulfillment of its function. This function, the exchange of gases and nutrients with the cerebral parenchyma, is the subject of a subsequent section on the microcirculation and blood-brain barrier. Finally, the cerebral venous system, which is composed of cerebral veins and dural venous sinuses, is described. Thus, an anatomical context is supplied for the discussion of cerebrovascular disease pathogenesis provided by our second paper.

A5 segment aneurysm of the anterior cerebral artery, imbedded into the body of the corpus callosum: A case report

BACKGROUND

The A5 segment aneurysms of the anterior cerebral artery are rare, approximately 0.5% of all intracranial aneurysms. They are small with a wide base located in the midline, with the domes mostly projecting upward or backward.

CASE DESCRIPTION

The authors describe a unique case of A5 segment aneurysm, with the dome embedded into the body of the corpus callosum. This 41-year-old female was admitted to the neurology department for possible multiple sclerosis investigation. Computed tomography angiogram (CTA) revealed a 4-mm right-sided pericallosal artery aneurysm, with rare configuration, which was caudally projected, embedded into the body of the corpus callosum. Considering the family history, patient underwent a prophylactic ligation surgery. The postoperative CT and CTA showed no complication and successful occlusion of the aneurysm with no ischemia or hemorrhage in the corpus callosum.

CONCLUSION

To the best of our knowledge, this is the first case of an aneurysm with this configuration. Our rare case of A5 segment aneurysm demonstrates the importance of planning of the surgery, choosing the appropriate approach, and knowing the detailed anatomy of the region, as well as the necessity of microsurgical clipping of small unruptured AdistAs.

Description of the anterior cerebral artery and its cortical branches: Variation in presence, origin, and size

OBJECTIVE

Certain aspects of the anterior cerebral artery (ACA) cortical branches tend to vary, including absent or additional arteries, variation in origin, and changes to diameter and length. Knowledge of these factors can be crucial in aneurysm and arteriovenous malformation surgery. Few studies report on these aspects and a South African study have not been completed. Therefore, the aim of this study is to report absent or additional arteries, the origin, diameter and length of ACA cortical branches in a Western Cape population.

METHODS

A coloured silicone was injected into the ACA of 121 hemispheres (60 right, 61 left), consisting of 83 males and 38 females. Specimens were divided in groups younger than 34 (n=36), between 35 and 48 (n=35), older than 49 (n=40), and unknown (n=10). There were three population groups; coloured (n=72), black (n=37), white (n=10), and unknown (n=2). Any absent or additional arteries were noted, as well as the origins. External diameter and lengths were measured using a digital micrometre, string and a ruler.

RESULTS

The diameter and lengths indicated significant differences between right and left, sex, age and population groups. Most commonly absent (callosomarginal artery) and additional (paracentral lobule artery) arteries were noted. Origins were similar to the literature; however, previously unreported origins and common trunks were also observed.

CONCLUSION

The aspects reported have been neglected in previous work and neurosurgeons should be aware of these variations and anomalies to avoid complications. Studies should continue to assess the cerebral vasculature since undocumented variations are still being reported.