Safety and anatomical outcome analysis after flow diverter coverage of the anterior cerebral artery

OBJECTIVES

Few studies on ischemic complications and flow changes after a flow diverter covering the anterior cerebral artery. The purpose of the study was to explore the ischemic complications and anatomical alterations associated with the flow diverter after it covers the anterior cerebral artery.

MATERIALS AND METHODS

In this single-center study, patients treated with FD covering the anterior cerebral artery at the First Affiliated Hospital of Zhengzhou University were retrospectively collected. The primary endpoint was ischemic complications related to the anterior cerebral artery. Secondary endpoints were anatomical changes in the anterior cerebral artery postoperatively and at follow-up.

RESULTS

A total of 59 patients were included in this study. Four (6.8%) patients presented with ischemic stroke symptoms. Immediately after the procedure, complete occlusion of A1 and decreased blood flow was observed in 13 (22.0%) and 21 patients (35.6%), respectively. At follow-up, A1 artery was occluded in 34 patients (57.6%) and decreased blood flow was observed in 10 patients (16.9%). Symptoms of neurological deficits related to the anterior cerebral artery were not observed in all patients at follow-up.

CONCLUSION

Coverage of A1 is safe, with a low incidence of ischemic stroke, when using an FD to treat aneurysms. Risk of reduced perfusion of the anterior cerebral artery postoperatively even if the anterior communicating artery is open. In cases with A1 occlusion, the blood flow in the distal the anterior cerebral artery can be adequately compensated by opening the anterior communicating artery and good vascular anastomoses.

Effect of revascularization surgery on cerebral hemodynamics in adult moyamoya disease

OBJECTIVE

Few studies have reported local hemodynamic changes after revascularization surgery. This study aimed to identify regional hemodynamic changes after combined revascularization surgery for moyamoya disease using single-photon emission computed tomography with N-isopropyl-p-123I-iodoamphetamine.

METHODS

A total of 46 adults with moyamoya disease who underwent combined revascularization surgery from August 2009 to July 2021 at our facility were enrolled. The combined bypass procedure comprised a single direct bypass to the motor area and encephalo-duro-arterio-myo-synangiosis. The preoperative and postoperative cerebral blood flow (CBF) and cerebral vascular reserve (CVR) in the genu; precentral, central, parietal, angular, temporal, and posterior regions; splenium; hippocampus; and cerebellum were measured. To modify the examination variability, the cerebral-to-cerebellar activity ratio (CCR) was calculated by dividing the counts in the region by those in the cerebellum (CBF-CCR and CVR-CCR).

RESULTS

Postoperatively, asymptomatic cerebral infarction occurred in three (6.5%) patients. The CBF-CCR and CVR-CCR improved in the precentral, parietal, and temporal regions and in the overall middle cerebral artery (MCA) territory. Sub-analysis of anterior cerebral artery (ACA) and posterior cerebral artery (PCA) territory hemodynamics revealed that patients with normal preoperative hemodynamics showed no changes in the CBF-CCR and CVR-CCR postoperatively, whereas patients with preoperative perfusion impairment exhibited improved CVR-CCR in the ACA territory (0.13-0.3, p=0.019) and CBF-CCR in the PCA territory (0.93-0.96, p=0.0039).

CONCLUSION

Combined revascularization surgery with single bypass to the motor area improved hemodynamics in the primary targeted MCA territory and in the ACA and PCA territories among patients with preoperative hemodynamic impairment.

Endovascular treatment of patients with stroke caused by anterior cerebral artery occlusions

BACKGROUND

Occlusion of the anterior cerebral artery (ACA) is uncommon but may lead to significant disability. The benefit of endovascular treatment (EVT) for ACA occlusions remains uncertain.

METHODS

We included patients treated with EVT and compared patients with ACA occlusions with patients who had internal carotid artery (ICA) or proximal (M1/M2) middle cerebral artery (MCA) occlusions from the MR CLEAN Registry. Primary outcome was the modified Rankin Scale score (mRS). Secondary outcomes were functional independence (mRS 0-2), National Institutes of Health Stroke Scale (NIHSS) score, delta-NIHSS (baseline minus NIHSS score at 24-48 h), and successful recanalization (expanded thrombolysis in cerebral infarction (eTICI) score 2b-3). Safety outcomes were symptomatic intracranial hemorrhage (sICH), periprocedural complications, and mortality.

RESULTS

Of 5193 patients, 11 (0.2%) had primary ACA occlusions. Median NIHSS at baseline was lower in patients with ACA versus ICA/MCA occlusions (11, IQR 9-14; versus 15, IQR 11-19). Functional outcome did not differ from patients with ICA/MCA occlusions. Functional independence was 4/11 (36%) in patients with ACA versus 1949/4815 (41%) in ICA/MCA occlusions; median delta-NIHSS was - 1 (IQR - 7 to 2) and - 4 (IQR - 9 to 0), respectively. Successful recanalization was 4/9 (44%), versus 3083/4787 (64%) in ICA/MCA occlusions. Mortality was 3/11 (27%) versus 1263/4815 (26%). One patient with ACA occlusion had sICH; no other complications occurred.

CONCLUSION

In this cohort ACA occlusions were uncommon. Functional outcome did not differ between patients with ACA occlusions and ICA/MCA occlusions. Prospective research is needed to determine feasibility, safety, and outcomes of EVT for ACA occlusions.

Anatomical Variations and Anomalies of the Anterior Communicating Artery Complex

BACKGROUND

Intracranial arteries have a high rate of variation, but a clear schematic overview is lacking. In this pictorial review we classify and depict all variations and anomalies within the anterior communicating artery complex.

METHODS

PubMed was searched with the terms "Anterior Communicating Artery" AND "Variations" OR "Anomalies." Articles were selected based on their description of variants. Cross-referencing was used to broaden the range of variations. Surgical view during pterional craniotomy and transsylvian approach was used as a baseline for schematic drawings of the variations.

RESULTS

A total of 42 variants were identified, schematically drawn and classified into A1-A2 segment, anterior communicating artery, and the recurrent artery of Heubner.

CONCLUSIONS

The anterior communicating artery complex consists of the anterior cerebral artery, anterior communicating artery and the recurrent artery of Heubner. An overview of these variations may be helpful in distinguishing pathology from anatomical variations, assist neurosurgeons during clipping of cerebral aneurysms, and support interventional radiologists during endovascular treatments. This article summarizes the current knowledge of anatomical variations within the anterior communicating artery complex, their prevalence and clinical relevance. A total of 42 variants were identified and schematically depicted. We encourage all who diagnose, treat, and study the anterior communicating artery complex to use this overview for a uniform and better understanding of its anatomy.

Risk factor analysis of changes in blood flow in the A1 segment of the anterior cerebral artery after flow-diverter coverage of it

Few studies have explored the effect of a flow-diverter device (FD) on blood flow in the A1 segment of the anterior cerebral artery (ACA), after treatment of intracranial aneurysms in the bifurcation region of the internal carotid artery (ICA). The main objective of this article is to investigate the factors that affect A1 blood flow after FD covers the A1 artery. This is a single-center, retrospective study. Data were collected retrospectively from our center, and patients whose FDs were placed for treatment from the terminal of the ICA to the M1 segment were analyzed. A total of 42 patients were included in the study. Immediate post-procedural angiography following device placement revealed decreased blood flow in the A1 of 15 (35.7%) patients and complete occlusion of the A1 segment in 11 (26.2%) patients. During an average follow-up period of 9.8 months, the A1 segment was ultimately occluded in 25 patients (59.5%) and decreased blood flow in 4 patients (9.5%). When using FD to cover the A1 artery for the treatment of intracranial aneurysms, patients with preoperative opening of the anterior communicating artery (AcomA) are more prone to occlusion or decreased blood flow of the A1 artery, compared to patients without opening.

Dominant A1 Direction as an Additional Factor for Deciding Surgical Approach for A1 Bifurcation Aneurysms

BACKGROUND AND OBJECTIVE

Clipping of aneurysms located in the anterior communicating artery (AcomA) is considered a critical surgical procedure for neurosurgeons worldwide because of the complexity of the surgical area. The present study was conducted to discuss the importance of the geometric curvatures and the direction of the dominant A1 artery and their impact on aneurysmal growth direction and choice of side selection of the pterional surgical approach side.

METHODS

The present study enrolled 183 patients with ruptured AcomA-located aneurysms. The aneurysms were all treated surgically through a pterional approach. Because of multiple dominant A1 directions, we divided the artery into 2 segments, and based on the second segment direction, we categorized the patients into ascending A1, descending A1, and horizontal A1 groups. The ascending group includes the superiorly projecting aneurysms, whereas the horizontal and descending groups include the anteriorly and inferiorly projecting aneurysms, respectively. A contralateral pterional approach to the dominant A1 was chosen for aneurysms with an ascending artery. However, the ipsilateral pterional approach was conducted in the horizontal and descending A1 dominant groups.

RESULTS

The aneurysmal growth projection axis always follows the direction of the second dominant A1 segment. Full neck control with satisfactory inspection of perforators was achieved through the contralateral approach in most cases of an ascending A1, especially if ipsilateral A2 was posterior to the neck. The A1 segment can be satisfactorily seen from the contralateral exposure before the aneurysmal neck is exposed in ascending A1 geometries.

CONCLUSIONS

A1 direction is an important additional factor that is to be considered for side selection when deciding pterional exposure of A1 bifurcation aneurysms. Accessing the contralateral dominant ascending A1 has better visualization of the neck than entering from an ipsilateral approach, especially if the ipsilateral A2 was posterior to the neck.

The biportal transorbital approach: quantitative comparison of the anterior subfrontal craniotomy, bilateral transorbital endoscopic, and microscopic approaches

OBJECTIVE

The aim of this study was to assess the surgical use and applicability of a biportal bitransorbital approach. Single-portal transorbital and combined transorbital transnasal approaches have been used in clinical practice, but no study has assessed the surgical use and applicability of a biportal bitransorbital approach.

METHODS

Ten cadaver specimens underwent midline anterior subfrontal (ASub), bilateral transorbital microsurgery (bTMS), and bilateral transorbital neuroendoscopic surgery (bTONES) approaches. Morphometric analyses included the length of the bilateral cranial nerves I and II, the optic tract, and A1; the area of exposure of the anterior cranial fossa floor; craniocaudal and mediolateral angles of attack (AOAs); and volume of surgical freedom (VSF; maximal available working volume for a specific surgical corridor and surgical target structure normalized to a height of 10 mm) of the bilateral paraclinoid internal carotid arteries (ICAs), bilateral terminal ICAs, and anterior communicating artery (ACoA). Analyses were conducted to determine whether the biportal approach was associated with greater instrument freedom.

RESULTS

The bTMS and bTONES approaches provided limited access to the bilateral A1 segments and the ACoA, which were inaccessible in 30% (bTMS) and 60% (bTONES) of exposures. The average total frontal lobe area of exposure (AOE) was 1648.4 mm2 (range 1516.6-1958.8 mm2) for ASub, 1658.9 mm2 (1274.6-1988.2 mm2) for bTMS, and 1914.9 mm2 (1834.2-2014.2 mm2) for bTONES exposures, with no statistically significant superiority between any of the 3 approaches (p = 0.28). The bTMS and bTONES approaches were significantly associated with decreases of 8.7 mm3 normalized volume (p = 0.005) and 14.3 mm3 normalized volume (p < 0.001) for VSF of the right paraclinoid ICA compared with the ASub approach. No statistically significant difference in surgical freedom was noted between all 3 approaches when targeting the bilateral terminal ICA. The bTONES approach was significantly associated with a decrease of 105% in the (log) VSF of the ACoA compared with the ASub (p = 0.009).

CONCLUSIONS

Although the biportal approach is intended to improve maneuverability within these minimally invasive approaches, these results illustrate the pertinent issue of surgical corridor crowding and the importance of surgical trajectory planning. A biportal transorbital approach provides improved visualization but does not improve surgical freedom. Furthermore, although it affords impressive anterior cranial fossa AOE, it is unsuitable for addressing midline lesions because the preserved orbital rim restricts lateral movement. Further comparative studies will elucidate whether a combined transorbital transnasal route is preferable to minimize skull base destruction and maximize instrument access.

Coil Embolization of the Azygos Anterior Cerebral Artery Aneurysm: Three Case Reports

The azygos anterior cerebral artery (ACA) is a rare anatomical anomaly. Clipping surgery has been conducted in approximately 30 reported cases because it is frequently associated with aneurysms. However, few cases in which coil embolization was performed have been reported. We report three cases of coil embolization for distal ACA aneurysms with distal azygos ACA at our institution in 7 years. All patients were over 65-year-old women with saccular aneurysms larger than 7 mm; two with subarachnoid hemorrhage and one with an unruptured aneurysm. No patient had surgical complications associated with coil embolization. Coil embolization is also useful for large aneurysms in the distal azygos ACA, and its indication for treatment could be broadened.

Fusiform aneurysms of anterior cerebral artery: center experience and systematic literature review

Fusiform aneurysms of the anterior cerebral artery (ACA) are uncommon, and the natural history of this entity is poorly characterized. Along with our center experience, we conducted a systematic literature review to help shed light on the clinical course of ACA fusiform aneurysms. We queried our institutional database to identify cases with fusiform aneurysms of ACA. In addition, following the PRISMA algorithm, we identified all reported cases published in the English literature from the inception of PubMed until December 2022. We categorized clinical presentations into three categories: (i) traumatic/iatrogenic, (ii) spontaneous symptomatic ruptured/unruptured, and (iii) spontaneous asymptomatic aneurysms. We utilized descriptive statistics. We identified seven cases from our center along with 235 patients from published literature. Blunt trauma was responsible for the development of 19 aneurysms. Sixty-three percent of these aneurysms tend to rupture within 2 weeks from the initial trauma, and despite treatment, only 74% of these patients had good clinical outcomes. Spontaneous symptomatic presentation occurred in 207 patients and was often associated with previous/concomitant ACA dissection. Subarachnoid hemorrhage from ruptured aneurysms was the most common presentation. Spontaneous symptomatic fusiform aneurysm is rapidly evolving lesions, and treatment is necessary. Three of our own cases were treated with an endovascular flow diverter (pipeline) stenting with good outcomes. Spontaneous asymptomatic aneurysms were reported in nine patients. These lesions are often associated with other vascular abnormalities. Treatment included surgical clipping with good clinical outcomes. Instead, four patients from our center database were managed conservatively with equally good outcomes. Our study demonstrates good clinical outcomes when fusiform aneurysms of ACA, especially when symptomatic, are treated promptly with either reconstructive or deconstructive therapies.

Superficial temporal artery interposition bypass for the treatment of complex intracranial aneurysms: Flexible and creative options for flow preservation bypass

PURPOSE

Flow-preservation bypass is a treatment option for complex intracranial aneurysms (IAs) that cannot be managed with microsurgical clipping or endovascular treatment. Various bypass methods are available, including interposition grafts such as the radial artery or saphenous vein. Size discrepancy, invasiveness, and procedure complexity must be considered when using interposition grafts. We describe our experience of treating complex IAs using a superficial temporal artery (STA) interposition bypass.

METHODS

We retrospectively reviewed the medical records and operative videos of all patients who were treated for complex IAs at our center from January 2009 to December 2021 using cerebral revascularization. Clinical, radiological, and surgical findings of the cases that underwent STA interposition bypass were investigated.

RESULTS

Seventy-six bypass procedures were performed of which seven (9.2%) complex IAs were managed using STA interposition bypass. Of these 5 cases were of anterior cerebral artery, 1 of middle cerebral artery, and 1 of posterior inferior cerebellar artery aneurysm. There were no postoperative ischemic complications. Revision surgery for postoperative pseudomeningocele was performed in one case. The long-term bypass patency rate was 85.7% (6 out of 7) and good long-term aneurysm control was achieved in all cases, with a mean follow-up of 64 months.

CONCLUSIONS

When treating complex IAs, creative revascularization strategies are needed in selective cases for favorable outcomes. STA interposition graft bypass which can reduce the size discrepancy between the donor and recipient may be a less invasive, flexible, and practical option for treating complex IAs.

Left anterior cerebral artery arising from a right internal carotid artery: a rare case of carotid-anterior cerebral artery anastomosis

Carotid-anterior cerebral artery anastomosis (carotid-ACA anastomosis) is described as infrequent vascular connections between the pre-ophthalmic segment of the internal carotid artery (ICA) and the A1 segment of the anterior cerebral artery (ACA). The embryological origin of these variant is still unclear and they are often associated to other vascular anomalies of the circle of Willis, as well as to the presence of aneurysms. Carotid-ACA anastomosis is often right-sided although left and bilateral cases have also been described. We report a rare case by MR angiography of a carotid-ACA anastomosis in which the abnormal vessel arises from the right ICA and takes an infraoptic course to join the A2 segment of the contralateral ACA, making this vascular anomaly function as a 'left ACA with an origin at the right ICA'. The A1 segment of the left ACA is absent and both A2 segments of the ACAs present fenestration. To our knowledge, no similar cases have been reported in English literature so far.

Fenestrated Anterior Cerebral Artery, Anterior Communicating Artery, with Accessory Middle Cerebral Artery-A Conglomeration of Embryologically Different Entities in a Single Individual

Cerebral arterial fenestrations are anatomic variants of undetermined significance where there is a division of a single vessel into at least 2 channels, each having endothelial and muscular layers, that coalesce to a single lumen in the distal course of the vessel. The basilar artery is the most common site, followed by the anterior communicating artery. The accessory middle cerebral artery is defined as the anomalous origin of the vessel from the anterior cerebral artery and its further course along the sylvian fissure parallel to the middle cerebral artery. The embryologic basis of all these has been explained by studies on human embryological development by Padget et al. However, simultaneous existence of all 3 anomalies in a single individual has never been reported. Here we present a case of medial sphenoid wing meningioma with these incidental findings during workup and further delineation of anatomy following surgical resection of meningioma.

Unreported branching pattern of the triplicated anterior cerebral artery associated with multiple bilateral variants of the superior cerebellar artery detected by computed tomography angiography and 3D modeling

A 26-year-old patient underwent a successful ablation of Grade 2 diffuse astrocytoma of the right parietal lobe. The postoperative computed tomography angiography with 3D modeling revealed a residual avascular porencephalic cyst. Otherwise, multiple arterial variants have been encountered. First, the left A1 segment was fenestrated, and three A2 segments arose from the anterior communicating artery. The middle A2 segment was dominant and supplied left callosomarginal and both pericallosal territories. The right A2 segment supplied the right callosomarginal territory, while the left A1 was limited to the left orbitofrontal and frontopolar territories. This configuration represents a triplicated anterior cerebral artery with an unusual branching pattern not included in the classification of Baptista. In addition, on both sides, superior cerebellar artery duplication was present, with one arising from the basilar artery and the other from the P1 segment of the ipsilateral posterior cerebral artery. The left lower superior cerebellar artery was early bifurcated. It is the first time such a cerebrovascular configuration has been reported. Because of the several clinical and surgical applications of the anterior cerebral artery and superior cerebellar artery variants, this case report is of utmost interest to anatomists, radiologists, and neurosurgeons.

Selective clipping of giant anterior communicating artery aneurysms remains a reliable therapeutic option

BACKGROUND

Giant anterior communicating artery (AcomA) aneurysm represent a significant surgical challenge. Our study aimed to discuss the therapeutic strategy in patients with a giant AcomA aneurysm treated by selective neck clipping through a pterional approach.

METHODS

Among all operated patients from an intracranial aneurysm between January 2015 and January 2022 (n = 726) in our institution, three patients with a giant AcomA aneurysm treated by neck clipping were included. Early (<7days) outcome was noted. Early postoperative CT scan was performed in all patients to detect any complications. Early DSA was also performed to confirm giant AcomA aneurysm exclusion. The mRS score was recorded 3 months after treatment. The mRS≤ 2 was considered as a good functional outcome. Control DSA was performed one year after treatment.

RESULTS

In the three patients, after a large frontopterional approach, a selective exclusion of their giant AcomA aneurysm was obtained after a partial pars orbitalis of the inferior frontal gyrus resection. Ischemic lesion was noted in 1 patient and chronic hydrocephalus in 2 patients with ruptured aneurysm. The mRS score after 3 months was good in 2 patients. Long term complete occlusion of the aneurysm were noted in the three patients.

CONCLUSION

Selective clipping of a giant AcomA aneurysm is a reliable therapeutic option after a careful evaluation of local vascular anatomy. An adequate surgical exposure is frequently obtained through an enlarged pterional approach with an anterior basifrontal lobe resection, especially in an emergency situation and/or in case of high position of anterior communicating artery.

Contralateral transfalcine approach for resection of right medial frontal AVM

Brain arteriovenous malformations (AVMs) are high flow vascular lesions that can cause significant morbidity and mortality [1-6]. We present a case of a 23-year-old woman who initially presented to an outside institution with a ruptured right medial frontal Spetzler Martin grade II AVM. An EVD was placed and a diagnostic angiogram with partial embolization was performed. She was then transferred to our institution two months post rupture for further care. On arrival, she was trached with eyes opening to voice and localizing in bilateral upper extremities and withdrawing in bilateral lower extremities. Diagnostic angiogram demonstrated arterial supply from the right pericallosal and callosomarginal artery, right posterior cerebral artery callosomarginal branch, distal left anterior cerebral artery (ACA) branches with venous drainage via a cortical vein to the superior sagittal sinus. The patient underwent preoperative embolization of the ACA feeders followed by a contralateral interhemispheric transfalcine approach. An interhemispheric dissection was performed down to the corpus callosum and AVM feeders and draining veins were identified. The falx was then incised to expose the right medial frontal lobe. The AVM was circumferentially dissected and resected. Postoperative imaging demonstrated complete resection of the AVM. She remained at her neurological baseline immediately postoperatively and was discharged to inpatient rehab. The patient made a remarkable recovery and at three months follow up, she no longer required a tracheostomy and was neurologically intact with no complaints except for mild memory difficulties. In this video, we demonstrate the step-by-step surgical technique and review the benefits of the contralateral transfalcine approach for resection of a ruptured right medial frontal Spetzler Martin grade II AVM. The patient consented to the procedure and to the publication of her imaging in this surgical video.

Funnel Shaped Anterior Communicating Artery Fenestration Mistaken for an Aneurysm: A Cautionary Tale

This report portrays a case of a funnel shaped anterior communicating artery (ACoA) fenestration which was mistaken as a small A1 aneurysm in a subarachnoid hemorrhage case. Although tridimensional rotational digital subtraction angiography improves aneurysm diagnosis specially at the ACoA complex, current spatial resolution might leave behind a considerable percentage of ACoA fenestrations. This may lead to diagnostic errors and unnecessary treatments risking iatrogenic complications. Luckily for our patient, a concomitant aneurysm warranted clipping and subsequent surgical exploration of the ACoA complex revealed the pitfall, thus preventing further action. Interestingly, another group of authors who reported similar misdiagnosis with ACoA aneurysms were able to prevent a third error, thanks to the experience acquired with 2 prior cases. Therefore, this clinical image aims to raise wider awareness of the need for very cautious consideration of imaging depicting small and/or atypical aneurysms in the ACoA complex.

False Absence of the Anterior Communicating Artery and a Median Artery of Corpus Callosum

The anterior communicating artery (AComA) normally joins the anterior cerebral arteries (ACAs) when they change their directions from horizontal to vertical. Each postcommunicating segment of the ACAs commonly sends off the callosomarginal artery (CMA) and continues as the pericallosal artery. While documenting the archived computed tomography angiogram of a 61-year-old male patient, a rare anatomic variant was found to be associated with a previously unreported one. Both ACAs had symmetrical horizontal and vertical segments, but the AComA was absent from the usual location. The right ACA continued as CMA without sending off a pericallosal artery. A median artery of corpus callosum (MACC) left from the horizontal segment of the left ACA. Then the left ACA continued as CMA. At 1.9 cm from its origin, the MACC was united to the right CMA by a high, interhemispheric AComA. Therefore, an AComA should be regarded as absent only after documenting the bilateral anastomoses within the interhemispheric fissure. A third interhemispheric main artery, such as a rarely occurring MACC, could be accurately documented by computed tomography angiogram to avoid unpleasant intraoperative hemorrhage or to establish a personalized endovascular route to the anterior cerebral system.

Transcallosal and Pericallosal Courses of the Anterior Cerebral Artery

(1) Background: The anterior cerebral artery (ACA) has a precommunicating A1 segment, followed by a postcommunicating A2 segment. Anatomically, after it sends off from the callosomarginal artery (CMA), it continues as the pericallosal artery (PCalA). A detailed pattern of the anatomical variations of the PCalA are needed for practical reasons. (2) Methods: There were 45 retrospectively documented Computed Tomography Angiograms of 32 males and 13 females. (3) Results: In 90 sides, eleven different types of PCalA were documented: type 1: normal origin, above the genu of the corpus callosum (CC) (51.11%); type 2: low origin, below the rostrum of the CC (8.88%); type 3: late origin, above the body of the CC (3.33%); type 4, initial transcallosal course (3.33%); type 5, duplicated PCalA (1.11%); type 6, azygos PCalA (2.22%); type 7, absent PCalA (CMA type of ACA) (7.78%); type 8: CMA continued as PCalA (5.56%); type 9: PCalA continued as the cingular branch (1.11%); type 10: PCalA type of ACA, absent CMA (14.44%); type 11: triple PCalA, with an added median artery of the CC (1.11%). Different types of CMA were also documented: type 0, absent CMA (17.78%); type 1, CMA with frontoparietal distribution (45.56%); type 2, CMA with parietal distribution (22.22%); type 3, low origin of CMA, either from A1, or from A2 (8.88%); type 4, CMA continued as PCalA (5.56%). Ipsilateral combinations of PCalA and CMA types were classified as types A-P. In 33/45 cases (73.3%), the bilateral asymmetry of the combined anatomical patterns of PCalA and CMA was documented. Additional rare variations were found: (a) huge fenestration of A2; (b) bihemispheric ACAs (6/45 cases); (c) twisted arteries within the interhemispheric fissure. (4) Conclusions: The PCalA and CMA are anatomically diverse and unpredictable. Therefore, they should be documented on a case-by-case basis before surgical or endovascular approaches.

The Infraoptic or Infrachiasmatic Course of the Anterior Cerebral Artery Emerging an Elongated Internal Carotid Artery

(1) Background: The normal A1 segment of the anterior cerebral artery (ACA) has a supraoptic course. The proximal infraoptic course of an A1 segment leaving the internal carotid artery (ICA) near the origin of the ophthalmic artery is a rare possibility. This study aimed to determine the prevalence and detailed anatomy of infraoptic A1 segments. (2) Methods: We retrospectively studied 145 computed tomography angiograms from 92 male and 53 female cases, with ages varying from 61 to 78 y.o. (3) Results: In 21/145 cases, infraoptic or infrachiasmatic horizontal-medial courses of A1 segments that emerged distally from the ICA were found. Distal infraoptic A1 segments were bilateral in 16/145 cases and unilateral in 3/145 cases. Infrachiasmatic A1 segments were found bilaterally in 2/145 male cases. All the infraoptic/infrachiasmatic A1 segments left long ICAs with low bifurcations. In 7/34 sides with distal infraoptic or infrachiasmatic A1 segments, supracarotid courses were present. In one female, the right A1 segment had an anterior supraclinoid, supracarotid and infraoptic course. In two female cases with a bilateral distal infraoptic A1, the segment was almost contacting the respective posterior cerebral artery. (4) Conclusions: In cases with dolicho(ectatic) ICAs, the A1 segments could have infraoptic and supracarotid courses the neurosurgeons should be aware of.

How I do it: left posterior cerebral artery P1-2 segment dissecting aneurysm distal clipping via an A1-RAG-P2 bypass

BACKGROUND

Posterior cerebral artery (PCA) P1-2 segment dissecting aneurysms are difficult because regular craniectomy aneurysm clipping or intravascular interventional therapy is not applicable.

METHOD

We report distal clipping of a PCA P1-2 segment dissection aneurysm with an anterior cerebral artery (ACA) A1-radial artery graft-PCA P2 bypass.

CONCLUSION

This case demonstrates the value of an ACA-RAG-PCA bypass in the therapy of a PCA dissecting aneurysm.

Superficial temporal artery lengthening technique to prevent postoperative wound complications in direct revascularization to the anterior cerebral artery for Moyamoya disease

BACKGROUND

Neurocognitive dysfunctions or psychomotor symptoms of Moyamoya disease may improve after direct revascularization to the anterior cerebral artery (ACA). However, long-distance harvest of the frontal branch of the superficial temporal artery (STA) is needed to reach the cortical ACA, frequently resulting in postoperative wound complications. To solve this problem, we devised a novel method (STA lengthening technique). In this study, we compared the STA lengthening technique and the conventional method regarding postoperative wound complications.

METHODS

Twenty-five patients who underwent STA-ACA direct bypass from December 2016 to October 2021 were retrospectively reviewed, and postoperative wound complications were recorded. Magnetic resonance angiography was performed to evaluate the patency of the bypass to the ACA and postoperative development of collaterals to the skin flap.

RESULTS

Thirty-eight hemispheres (new method [n = 12] vs. conventional method [n = 26]) were treated. Wound complications occurred in 12 surgeries (46%) of the conventional method, and none (0%) of the new method. The anastomosis with the cortical ACA was patent in all surgeries. Postoperative development of collaterals to the skin flap was confirmed after all surgeries (100%) in the new method, whereas after only five surgeries (20%) in the conventional method.

CONCLUSION

The STA lengthening technique can enable to preserve the collateral circulation to the skin flap postoperatively, resulting in good wound healing.

Revascularization to the ACA: effectiveness and variation of the STA-RAG-A3 bonnet bypass

BACKGROUND

The effectiveness of bypass surgery in patients with atherothrombotic ischemia in the anterior cerebral artery (ACA) domain remains unclear. In this study, three cases with ischemia in the ACA territory underwent revascularization surgery using superficial temporal artery (STA)-radial artery graft (RAG)-A3 (pericallosal artery) bonnet bypass. Herein, we discuss the effectiveness and variations of this approach.

METHODS

Among 182 consecutive patients with atherothrombotic ischemic stroke admitted to the NTT Medical Center, Tokyo, from April 2017 to May 2021, three patients with hemodynamic insufficiency in the extensive ACA territory beyond the recent infarct area were treated using STA-RAG-A3 bonnet bypass.

RESULTS

One patient with bilateral severe cerebral blood flow (CBF) deficiency required additional A3-A3 and STA-middle cerebral artery single bypass in conjunction with STA-RAG-A3 bypass. There were no complications associated with the surgical procedure. The patients' hemodynamic study results and neurocognitive performances improved dramatically after surgery.

CONCLUSION

Our results suggest the efficacy of STA-RAG-A3 bypass for atherothrombotic ACA ischemia. However, because the number of cases was too small to generalize our results, more cases and thorough pre- and postoperative hemodynamic studies are necessary to prove the validity of the approach.

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.

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.

Treatment of a Fusiform Anterior Cerebral Artery Aneurysm With an A3-A3 Bypass: 2-Dimensional Operative Video

Distal anterior cerebral artery (ACA) aneurysms remain a relatively rare and challenging entity for both open microsurgical and endovascular treatments. These lesions provide a significant surgical challenge because of the narrow interhemispheric surgical field, limited proximal control, common fixation of the aneurysm to the adjacent cingulate gyrus, and possible involvement of an unpaired azygos A2. These challenges result in a known association between distal ACA aneurysms and higher operative morbidity. This video demonstrates indirect obliteration of a prior ruptured fusiform right A2 aneurysm utilizing an A3-to-A3 side-to-side anastomotic bypass with aneurysm trapping. An anterior interhemispheric approach was used for exposure of bilateral ACAs, arteriotomies, microanastomosis, and trapping of the aneurysmal right A2 segment. Postoperatively, the patient's neurological status returned to baseline, and imaging demonstrated evidence of bypass patency with no residual filling of the fusiform aneurysmal segment. This video verifies the feasibility and efficacy of the A3-to-A3 anastomotic bypass for treatment of distal ACA aneurysms. The patient gave informed consent for surgery and video recording. Institutional review board approval was deemed unnecessary. Used with permission from Barrow Neurological Institute, Phoenix, Arizona.

Surgical treatment of traumatic distal anterior cerebral artery aneurysm: a report of nine cases from a single centre

BACKGROUND

Traumatic distal anterior cerebral artery (dACA) aneurysm is rare and can be easily neglected and misdiagnosed in patients with trauma. The aim of this study was to explore the radiologic characteristics of and therapeutic strategies for traumatic dACA aneurysm and to improve our understanding of unusual complications after trauma.

METHODS

The clinical data of nine cases of traumatic dACA aneurysm from our neurosurgical department from July 1, 2010, to July 1, 2018, were retrospectively analysed.

RESULTS

All 9 patients had a history of brain trauma. The initial computed tomography scan immediately after trauma showed subarachnoid haemorrhage in 8 cases. Among these cases, delayed intracranial haemorrhage occurred in 7 cases. The average interval between injury and diagnosis was 13.67 ± 9.43 days. All 9 cases were confirmed as traumatic dACA aneurysm by computed tomography angiography (CTA) and/or digital subtraction angiography. According to Lehecka's classification system, traumatic dACA aneurysm located in the A3 and A4 segment was found in 3 and 6 cases, respectively. Surgical treatment was performed in 8 cases, including neck clipping, with or without wrapping in 3 cases, trapping in 4 cases, aneurysm excision and suturing in 1 case and conservative treatment in 1 case. Three patients required a ventriculoperitoneal shunt due to severe hydrocephalus. According to the Glasgow Outcome Scale scoring system, good recovery was achieved in 4 cases, moderate disability in 2 cases, severe disability in 1 case, and death in 2 cases.

CONCLUSION

Traumatic dACA aneurysm is a rare complication of brain trauma. Delayed intracranial haemorrhage and the sudden deterioration of neurologic function were the typical characteristics in patients with traumatic dACA aneurysm. CTA is the first-line screening modality for patients who present with intracerebral haemorrhage in the corpus callosum after trauma, particularly for patients who are older, in a poorer or critical condition. When the aneurysm is located in the A4 segment or involves a small branch, surgical trapping is the preferred definitive therapy to prevent further growth and disastrous bleeding. Early diagnosis and prompt treatment could help to improve clinical outcomes.

Combined Pterional Transsylvian and Bifrontal Interhemispheric Approach to Ruptured Subcallosal and Pericallosal Brain Arteriovenous Malformation with Skeletonization of the Entire A2 ACA Segment

A 39-year-old man presented with a large left paramedian frontal lobe intracerebral hemorrhage. Computed tomography angiography and magnetic resonance imaging revealed a tangle of vessels arising from the anterior cerebral arteries (ACAs) and dilated draining veins entering the superior sagittal sinus. Angiography confirmed a Spetzler-Martin grade 3, supplemented 2 arteriovenous malformation (AVM) with predominant supply from branches of the left ACA with superficial and deep drainage (Video 1). The case illustrates an unusual cerebrovascular pathology involving the entire A2 ACA segment. The AVM extended from the A1/2 junction along the entire A2 segment past the genu of the corpus callosum (A3 segment). A combined pterional transsylvian and bifrontal interhemispheric approach was performed. The proximal sylvian fissure and opticocarotid cistern were opened to expose the A1/2 junction. Once proximal control was obtained, the hematoma was evacuated to define the lateral border of the AVM. The interhemispheric fissure was then opened to identify the draining vein and the distal pericallosal arteries. The interhemispheric approach also defined the medial border of the AVM. The A2 ACAs were then skeletonized from the AVM from the A1/2 junction to the pericallosal arteries. Aneurysm clips were used to interrupt large AVM feeders from the A2 arteries, which avoids cautery and heat transmission to the parent vessel. Once the AVM was disconnected and skeletonized from the A2s, the draining vein was clipped and the nidus was removed. Indocyanine green angiography confirmed patency of the A2s and pericallosal arteries. Postoperative angiography demonstrated no residual shunting, and the patient was discharged in good condition.

Modified encephalo-duro-periosteal-synangiosis (EDPS) for the revascularization of anterior cerebral artery territory in moyamoya disease: A single-center experience

OBJECTIVES

Anterior cerebral artery (ACA) territory, a crucial area of intellectual development in children, is frequently involved in the progress of moyamoya disease (MMD). However, revascularization surgeries for this area are not as established as surgeries for middle cerebral artery (MCA) territory. This study aimed to describe our experience and study the effect of revascularizing ACA territory with periocranium and dural leaflets, which is referred to as 'encephalo-duro-periosteal-synangiosis (EDPS)'.

PATIENTS AND METHOD

Fourteen hemispheres of 9 MMD patients who had undergone EDPS from November 2015 till July 2017 in our hospital were retrospectively included. Clinical characteristics and procedure-related information were recorded. Cerebral perfusion was evaluated by computed tomography perfusion (CTP). Absolute and relative (r) CTP parameters of ROIs in ACA territory at the level of centrum semiovale and middle basal ganglia were calculated. Preoperative and postoperative parameters were compared.

RESULTS

All EDPS procedures were technically successful with no postoperative complications. The mean operating time was 75.00 ± 22.53 min per hemisphere. Postoperative absolute cerebral blood flow (CBF), rCBF were significantly increased and absolute time to peak (TTP), rTTP, absolute mean transit time (MTT) were significantly reduced in ACA territory at centrum semiovale level (P = 0.002, 0.045, 0.007, 0.005 and 0.039 respectively). Improved outcomes were achieved in five patients, stabilization in three and one patient had deterioration out of intracerebral hemorrhage during follow-up.

CONCLUSION

EDPS is a simple but effective technique to revascularize ACA territory for MMD. EDPS significantly improved cerebral blood perfusion of frontal lobe in the majority of patients without increasing procedure-related risks.

[Combination of infraoptic anterior cerebral artery with an aneurysm of the ACA-AcomA complex. Case study and literature review]

The infraoptic anterior cerebral artery (ACA) is an abnormal vessel that usually is a bifurcation of the intradural part of the internal carotid artery (ICA) or near the site of discharge of the ophthalmic artery, which passes under the ipsilateral optic nerve and penetrates between the optic nerves into the prechiasm cistern, reaching the ACA-AcomA complex. The infra-optic ACA is an extremely rare anomaly, but it may be of great clinical significance in surgery of the arteries of the anterior sections of the Willis circle. The article describes the case of a combination of infra-optical ACA with an aneurysm of the ACA-AcomA complex. This observation is of interest both from the viewpoint of the rarity of the considered pathology and the associated increased risk of the formation of intracranial aneurysms.

STA-ACA bypass using the ipsilateral free STA graft as an interposition graft and A3-A3 anastomosis for treatment of bilateral ACA steno-occlusive ischemia

BACKGROUND

Anterior cerebral artery (ACA)-related ischemia is a rare entity in patients with atherosclerosis. Some surgical treatments are reported to date.

METHOD

We present the modification of intracranial-intracranial and intracranial-extracranial bypasses for symptomatic bilateral ACA steno-occlusive disease. The A3-A3 bypass followed by the superficial temporal artery-ACA bypass using the ipsilateral free superficial temporal artery graft is useful without harvesting of the radial artery.

CONCLUSION

Bilateral ACA steno-occlusive induced ischemia can be treated with tailored bypass procedures.

Retrograde Snare-Assisted Rescue via Anterior Communicating Artery for Lost Access During Multiple Overlapping Pipeline Embolization Device Placement

BACKGROUND

The Pipeline embolization device (PED; ev3, Irvine, California, USA) has been used to divert flow away from an aneurysm sac. The risk of complications may increase for flow diversion with giant aneurysms because these cases may require multiple overlapping PEDs, which makes the technique highly complex.

CASE DESCRIPTION

We report a rescue technical strategy for lost access during multiple overlapping PED placement for a giant, fusiform cavernous aneurysm.

CONCLUSIONS

By using the collateral circulation as an alternative rescue route, intraprocedural loss of distal access may be salvaged.

Rescue bypass for the treatment of pseudoaneurysm on the distal anterior cerebral artery: a case report of vertical side-to-side anastomosis of the distal callosomarginal artery-pericallosal artery

Pseudoaneurysm on the distal anterior cerebral artery (ACA) is rare but potentially fatal. It usually cannot be treated with typical treatment modalities. A 47-year-old female patient was diagnosed with a ruptured aneurysm on the pericallosal artery (PerA). During surgical exploration, it was found to be a pseudoaneurysm and could not be treated with clipping. We performed surgical trapping of the involved segment of the proximal PerA followed by side-to-side anastomosis between the ipsilateral PerA and the callosomarginal artery. The patient recovered without any neurologic deficit. This new method of anastomosis could be an alternative option.

Assessing the Role of Preoperative Embolization in the Surgical Management of Cerebral Arteriovenous Malformations

BACKGROUND

Preoperative embolization is established as an advantageous adjunct in multimodality treatment of cerebral arteriovenous malformations (AVMs). However, the benefit of preoperative embolization in AVMs with favorable surgical risk profile is debatable, because it has yet to be supported by evidence in comparative studies. In this study, we assessed outcome of surgically treated patients in a comparative setting.

METHODS

Our institutional AVM database of retrospectively and prospectively collected data between 1990 and 2015 was reviewed. Patients with complete clinical data who underwent surgical resection for AVMs were included. We performed a 1:1 ratio propensity score match for baseline variables that differed between patients with or without preoperative embolization. Differences in surgical risk and outcomes were evaluated between these 2 groups.

RESULTS

AVM size, eloquence, deep drainage, middle cerebral artery feeder, and ruptured presentation differed significantly between the 2 groups. Forty-eight patients without preoperative embolization were matched to 48 with embolization, with no significant differences in baseline variables or AVM characteristics between the 2 groups. We found no significant differences in AVM obliteration and postoperative modified Rankin Scale (mRS) score between embolized and nonembolized patients, respectively. Change in mRS score from preoperative score was also not significant, although more embolized patients had a decline in mRS score. Secondary outcome measures including duration of surgery (P = 0.172), intraoperative bleeding (P = 0.280), duration of hospitalization (P = 0.368), and postoperative symptoms were also similar between both groups.

CONCLUSIONS

Our data do not support substantial benefit of preoperative embolization for patients with a favorable surgical risk profile. Because of risks and costs with this intervention, the prudent use of preoperative embolization should be individually considered.

[Surgical management of proximal anterior cerebral artery (A1) aneurysms]

OBJECTIVE

To review our experience in surgical management of proximal anterior cerebral artery (A1) aneurysms in 23 patients.

METHODS

Between January, 2004 and December, 2014, 23 patients (1.6%) with A1 aneurysms diagnosed by CTA or DSA were treated surgically. The "3H" therapy was adopted for postoperative prevention of cerebrovascular spasm. All the patients were followed up and examined with cerebrovascular CTA at 6, 12, 48 and 60 months after the operation with their Glasgow Outcome Scale score recorded.

RESULTS

The patients consisted of 15 men and 8 women with an age range of 16 to 72 years (mean 51.3 years). The average diameter of the aneurysms was 5.8 mm, ranging from 3.2 to 9.7 mm. Twenty-two saccular aneurysms were found in these patients; 21 patients presented with SAH and two had vascular malformation. All the A1 aneurysms were managed through the pterional approach, and the mean postoperative Glasgow Outcome Scale score was 4.8.

CONCLUSION

Thorough analysis of the angiographic data is essential for the diagnosis and treatment of A1 aneurysms. Preservation of the perforators and prevention of aneurysm rupture are critical during the surgery. Full exposure of the Sylvian fissure and temporary occlusion of the parent artery ensures safe and effective dissection of A1 aneurysms.

Predicting the necessity of anterior communicating artery division in the bifrontal basal interhemispheric approach

Background

The anterior communicating artery (ACoA) often limits surgical exposure in the anterior interhemispheric approach. Although division of the ACoA has been proposed occasionally, it is rarely practiced, and criteria for such a surgical maneuver remain unknown. Our purpose was to identify key factors that allow for predicting the necessity of controlled ACoA division in the bifrontal basal interhemispheric approach.

Method

Twenty-two consecutive patients who underwent surgery via the bifrontal basal interhemispheric approach for removal of various pathologic brain lesions were examined. First, tumors were dichotomized into central and lateral lesions. Next, three tumor parameters were compared between cases with and without ACoA division in each, the central and lateral lesion groups, respectively: tumor volume, tumor depth (defined as distance between the ACoA and posterior tumor margin) and tumor laterality angle (defined as the geometric angle between the lateral tumor margin and sagittal midline).

Results

Tumor volume was not related in a statistically significant manner to ACoA division in both the central (P = 0.06) and lateral (P = 0.13) lesion groups, respectively. However, tumor depth was significantly correlated with ACoA division in the central lesion group (P = 0.01), whereas in the lateral lesion group, the tumor laterality angle showed a significant correlation with ACoA division (P = 0.04).

Conclusions

Our results suggest that controlled ACoA division may be required in central lesions with a depth of 38 mm or more and in lateral lesions with an angle of 23 degrees or more as defined in this study. Two key factors were thus identified that may predict the necessity of controlled ACoA division before surgery.

The outcome of a surgical protocol based on ischemia overprotection in large and giant aneurysms of the anterior cerebral circulation

Aiming to define the optimal treatment of large and giant aneurysms (LGAs) in the anterior circulation, we present our surgical protocol and patient outcome. A series of 42 patients with intracavernous LGAs (n = 16), paraclinoid (C2) LGAs (n = 17), and peripheral (middle cerebral artery—MCA or anterior cerebral artery—ACA) LGAs (n = 9) were treated after bypass under motor evoked potential (MEP) monitoring. Preoperatively, three categories of ischemic tolerance during internal carotid artery (ICA) occlusion were defined on conventional angiography: optimal, suboptimal, and insufficient collaterals. Accordingly, three types of bypass: low flow (LFB), middle flow (MFB) and high flow (HFB) were applied for the cases with optimal, suboptimal, and insufficient collaterals, respectively. Outcome was evaluated by the Glasgow Outcome Scale (GOS). All patients had excellent GOS score except one, who suffered a major ischemic stroke immediately after surgery for a paraclinoid lesion. Forty-one patients were followed up for 87.1 ± 40.1 months (range 13–144 months). Intracavernous LGAs were all treated by proximal occlusion with bypass surgery. Of paraclinoid LGA patients, 15 patients had direct clipping under suction decompression and other 2 patients with recurrent aneurysms had ICA (C2) proximal clipping with HFB. MEP monitoring guided for temporary clipping time and clip repositioning, observing significant MEP changes for up to 6 min duration. Of 9 peripheral LGAs patients 7 MCA LGAs had reconstructive clipping (n = 4) or trapping (n = 3) with bypass including LFB in 3 cases, MFB in 1 and HFB in 1. Two ACA LGAs had clipping (n = 1) or trapping (n = 1) with A3-A3 bypass. The applied protocol provided excellent results in intracavernous, paraclinoid, and peripheral thrombosed LGAs of the anterior circulation.

Ophthalmic artery originating from the anterior cerebral artery: anatomo-radiological study, histological analysis, and literature review

The ophthalmic artery has an anomalous origin in 2-3 % of cases and rarely arises from the anterior cerebral artery. Herein, we provide the first anatomical, radiological, and histological description of such an anomalous origin, together with a literature review. During the anatomical dissection of an 81-year-old Caucasian male, the absence of the right ophthalmic artery in its usual location was evident from an endonasal transsphenoidal perspective. The specimen was then studied in detail, through multiple dissections, corrosion casting, high-resolution CT, and histological analysis. The English literature on anomalous origins of the ophthalmic artery was reviewed, together with reported associated pathologies. Anatomo-radiological analysis documented that the right ophthalmic artery arose from the inferior surface of A1 tract of the anterior cerebral artery (A1) and passed over the optic nerve in its subarachnoid tract. A meningo-ophthalmic artery was evident on the same side and reached the orbit through the superior orbital fissure. Histological examination of both internal carotid artery (ICA) walls documented a significantly decreased thickness of the tunica media and adventitia on the side of the anomalous ophthalmic artery, with a significantly different content of collagen types I and III. The literature review documented an association of aneurysms and anomalous ophthalmic arteries. To the best of our knowledge, this is the first anatomical report that includes a radiological and arterial wall analysis of a persistent ventral ophthalmic artery. The latter provides histological data that support the clinical evidence of a higher association of aneurysms with anomalous origins of the ophthalmic artery.

Results of Clipping Surgery for Aneurysmal Subarachnoid Hemorrhage in Elderly Patients Aged 90 or Older

BACKGROUND

The number of elderly patients with aneurysmal subarachnoid hemorrhage (SAH) is increasing. Although advanced age is one of the recognized risk factors for poor outcome, conservative treatment for aneurysmal subarachnoid hemorrhage cannot provide satisfactory outcome in elderly patients. The aim of this study is to assess the outcome in patients aged 90 or older, for whom ruptured aneurysms were treated by clipping.

METHODS

We retrospectively reviewed the medical records of non-traumatic SAH patients who were hospitalized at the Chiba Neurosurgical Clinic between 2004 and 2013. Of the 702 patients, 8 patients (1.1 %) were aged 90 or older. Of them, four underwent clipping surgery and the other four died or were managed conservatively. Their preoperative conditions were evaluated with the World Federation of Neurosurgical Societies Grading Scale of SAH, and the Fisher classification was used to assess the bleeding severity. The location of the ruptured aneurysm was determined by three-dimensional computed tomographic angiography or cerebral angiography. The Glasgow Outcome Scale evaluation was assigned at discharge.

RESULTS

Four patients (four female, all WFNS grade 1), aged 90 or older, underwent clipping surgery. Fisher classification was three in two patients and four in the other two. Location of the ruptured aneurysm was internal carotid artery in two, anterior communicating artery in one, and posterior inferior cerebellar artery in one patient. Two of these four patients had a favorable outcome.

CONCLUSIONS

We propose that advanced age alone does not exclude suitable surgical clipping in patients with aneurysmal rupture in the tenth decade of life.

The extended endoscopic endonasal transplanum transtuberculum approach to the anterior communicating artery complex: anatomic study

BACKGROUND

When performing a transplanum transtuberculum approach, dealing with the anterior communicating artery (ACoA) complex is inevitable. The aim of this study is to provide quantitative anatomical information regarding the ACoA complex and its bony and neural relationships, when exposed through this approach.

METHOD

The endoscopic endonasal transplanum transtuberculum approach was performed on ten human cadaver heads. In each specimen, radiological studies were performed. A three-dimensional model of the approach was reconstructed. Measured parameters were: exposure of the vessels; distance between the proximal anterior cerebral artery (A1) and the optic chiasm; dimension of the bone opening. The feasibility to perform clip placement was graded as "possible" or "not possible".

RESULTS

Dimension of bone opening varied from 88 to 53 mm(2). The ACoA was exposed for 3 mm ± 2 mm, A1 for 17 mm ± 9 mm, the distal anterior cerebral artery (A2) for 12 mm ± 3 mm, the recurrent artery of Heubner (RAH) for 16 mm ± 4 mm. Clip placement was possible on the ACoA, A2, and distal segment of A1 in all cases, and on the proximal segment of A1 in one instance. The distance between A1 and the optic chiasm measured 9 mm ± 2 mm.

CONCLUSIONS

The ACoA, A2, and the distal segment of A1 can be visualized and controlled through the transplanum transtuberculum approach. The relationship between A1, gyrus rectus, and optic chiasm is the main determinant for the exposure and control of the vessel. The olfactory nerve can represent a surgical landmark for the identification of the A1 origin. The whole course of the RAH can be visualized trough this approach.

[A3-A3 side-to-side anastomosis combined with endovascular intervention in recurrent complex anterior artery aneurysm: a case report and literature review]

A 28-year-old female patient was admitted to the Second Affiliated Hospital, Zhejiang University School of Medicine, with sudden headache and vomiting for 1 day. CT scan conducted at emergency revealed subarachnoid hemorrhage, whereas digital subtraction angiography demonstrated a wide-neck aneurysm located at A1 segment of the left anterior cerebral artery. The aneurysm was totally coiled using stent assistance, which, however, was recanalized at 3 month follow-up. This patient was then subjected to aneurysm and parent artery occlusion after bypass of the bilateral A3 segments, who recovered well and discharged without ischemic complications.

Microsurgical efficacy and safety of a right-hemispheric approach for unruptured anterior communicating artery aneurysms

OBJECTIVE

We investigated the effectiveness of a right hemispheric surgical approach in treating unruptured anterior communicating artery aneurysms.

METHODS

Between January 2005 and June 2012, 305 patients with anterior communicating artery (Acom) aneurysms were treated using the pterional approach. Among them, 113 who underwent microsurgery with an unruptured Acom aneurysm were enrolled in this study. Every patient was evaluated with digital subtraction angiography preoperatively and CT scans were taken several times postoperatively. Surgical outcomes and complications were evaluated at discharge using the Glasgow Outcome Scale and at 6 months after surgery with CT angiography.

RESULTS

Enrolled patients included 55 males and 58 females with a mean age of 56.3 years (range: 30-75 years). The mean diameter of the aneurysm was 5.8mm (range: 1.9-24.1). Left A1 dominancy was found in 71 patients (62.8%) whereas right A1 dominancy was found in 20 patients (17.7%), and right pterional craniotomies were performed in 92 patients (81.4%) while left pterional craniotomies were performed in 21 patients (18.6%). Complete clip application was achieved in 94.9% of patients (74 of 78) in right-side approach group but in only 81.3% of patients (13 of 16) in left-side approach group. Despite a left A1 dominancy and approached from the right, more than 90% of the patients had an excellent outcome at discharge (GOS 5) and more than 90% a complete aneurysm clipping at the 6-month follow-up CT angiography although it was not statistically significant.

CONCLUSION

Microsurgical clipping of the unruptured Acom aneurysm through a right-side surgical approach showed favorable postoperative clinical and anatomical outcomes, especially aneurysms smaller than 10mm.

[Microsurgical anatomy of perforating branches of anterior communicating artery]

INTRODUCTION

The anterior communicating artery (ACoA) gives perforating branches to the optic chiasma, the hypothalamus and the corpus callosum. Perforating branches are variable (number, direction). Nevertheless, their knowledge is crucial during surgery of this area to spare injuries leading to ischemic post-operative complications.

OBJECTIVE

The objective was to update the anatomical knowledge about perforating branches of the ACoA.

METHODS

The study was led on a series of seven brains taken from human cadavers. An injection of latex neoprene was performed for every case. The region of interest was observed under operating microscope. Were examined: the length of the ACoA, its diameter, its orientation, its configuration and perforating branches (number and areas).

RESULTS

Three cases on five presented with an anatomical variation at the level of the ACoA. The average length of AcoA was 2.1 millimeters (min: 2, max: 2.2). The average diameter of the ACoA was 1.67 mm (min: 1.1, max: 2.1). The average number of perforating branches was 4.2 (min: 2, max: 6). The presence of a median artery of the corpus callosum seemed to correlated with a low number of perforating branches. Branches supplying the optic chiasma seemed to be more numerous.

Ruptured Giant Left Distal Anterior Cerebral Artery Aneurysm in a Two-Month-Old Baby

BACKGROUND

The incidence of intracranial aneurysm in childhood is rare, especially in infancy. In the literature, most of childhood intracranial aneurysms occur in the posterior and middle cerebral circulation. We report a case of a ruptured giant left distal anterior cerebral artery aneurysm in a 2-month-old baby. This report will discuss the rarity of this case as well as the diagnostic and surgical challenges in treating this condition.

CASE REPORT

A 2-month-old baby girl presented to our centre with a 1-day history of multiple afebrile seizures. A CT scan of her brain showed a large frontal interhemispheric acute bleed with intraventricular extension and acute hydrocephalus. An external ventricular drain was inserted and she was nursed in the Paediatric Intensive Care Unit. Subsequent CT angiogram and 4-vessel angiogram showed a giant aneurysm originating from the A3 segment of the left anterior cerebral artery. She underwent craniotomy and clipping and excision of the giant aneurysm.

DISCUSSION

Giant distal anterior artery aneurysms are very rare in infants. They are more commonly associated with the posterior and middle cerebral arteries. The aneurysms in infants tend to be larger compared to adults and they commonly present with subarachnoid haemorrhage and seizures. CT angiogram and 4-vessel cerebral angiogram are important diagnostic tools in this case. The angiogram demonstrated no distal runoff from the aneurysm and this assisted in our planning for surgical treatment of the aneurysm. A bifrontal craniotomy was done and the giant aneurysm was approached interhemispherically. The proximal and distal parent vessel was clipped and the aneurysm wall was excised. The baby recovered from surgery and did not require any cerebrospinal fluid diversion.

CONCLUSION

Giant distal anterior cerebral artery aneurysms are rare in infants. Detailed angiographic investigation is important. Surgery is the treatment of choice, although there may be a role for endovascular intervention.

[Two cases of anterior cerebral artery aneurysm associated with accessory anterior cerebral artery: review of the literature and points of diagnosis]

The accessory anterior cerebral artery (AccACA) is an anomalous vessel arising from the anterior communicating artery. Although AccACA is not particularly rare, aneurysms arising from the AccACA is extremely rare. Here, we report two cases of unruptured AccACA aneurysms. Patient 1 was a 58-year-old woman with an unruptured distal AccACA aneurysm. Magnetic resonance imaging and three-dimensional computed tomography angiography(3D-CTA)demonstrated a left middle cerebral artery aneurysm that was subsequently clipped successfully by direct surgery. No aneurysm was detected in the distal anterior cerebral artery(ACA)due to the narrow imaging range at that time. Postoperatively, an aneurysm of the distal ACA was incidentally identified on 3D-CTA. This AccACA aneurysm was also clipped by direct surgery about 5 months later, and the patient was discharged without any neurological deficits. Patient 2 was a 46-year-old woman with an aneurysm at the proximal portion of the AccACA. Since the aneurysm was small and patient was asymptomatic, the observation-approach was selected. In introducing these cases, we discuss AccACA aneurysms and the process of diagnosis. Aneurysm can arise over the entire length of the ACA, from the anterior communicating artery to the peripheral portion, particularly the supracallosal portion, so observation and imaging of the peripheral region is important in cases where an AccACA is present.

[A case of STA-A3 bypass with a STA interposition graft and endovascular trapping for a ruptured A2 dissecting aneurysm]

A 57-year-old man presented with sudden-onset consciousness disturbance. He had a 10-year history of a subarachnoid hemorrhage(SAH)caused by a ruptured aneurysm in the right middle cerebral artery, and had undergone aneurysmal clipping. He could perform all his daily life activities independently. Computed tomography showed diffuse SAH with intraventricular hemorrhage. Digital subtraction angiography(DSA)demonstrated mild fusiform dilatation of the left A2 portion of the left anterior cerebral artery(ACA)and the terminal portion of the left internal carotid artery with no sign of right middle cerebral artery(MCA)aneurysm recurrence. We could not identify the bleeding lesion at that time; therefore, conservative treatment was selected in the acute phase. Fourteen days later, repeated DSA showed fusiform dilatation of the left A2 portion leading to a diagnosis of ACA dissection. We initially performed superficial temporal artery(STA)-ACA anastomosis and secondary internal trapping with detachable coils in the operating room. Postoperative DSA revealed complete obliteration of the dissection and parent artery. Endovascular treatment with STA-ACA bypass is a safe and effective alternative for the treatment of ACA dissection.