Callosomarginal Artery Research Articles

Morphometric analysis of the arteries of Willis Polygon

Abstract Objective: Willis polygon forms the basis of the arterial circulation of the cerebrum. Willis polygon is a vascular structure whom variations are not rare. Knowledge of the anatomy and preservation of its integrity is crucial for performing neurovascular surgery and intracranial tumour surgery. Because of the important vascular and neurological structures, approaches to this region are considered extremely risky. One of the main variations in-person basis is the diameter differences of the arteries, which forms Willis polygon, between the left and right hemispheres. About structure and variations, studies of Rhoton and Yasargil had formed the touchstone. Our aim is to contribute to the literature and clinical studies, to be done in the future, by comparing our results with previous studies about variations and morphometric features of Willis polygon. Methods: Arteries of 30 fresh cadaver brains were examined during autopsies in T.C. Ministry of Justice Istanbul Forensic Science Institute. Bilaterally anterior cerebral artery A1 segment lengths, distance between anterior communicating artery-callosomarginal artery outputs, posterior cerebral artery P1 segment lengths were measured using a digital calliper. After dissections and measures, photos of the region were taken and vascular anatomy and variations noted. From every single cerebrum samples were obtained from bilaterally A1, A2, callosomarginal artery, middle cerebral artery, posterior communicant artery, P1 and basilar artery. Samples were fixed by using 10% buffered-formalin. Taken samples were transported to Marmara University Faculty of Medicine, Department of Anatomy Laboratory. Samples were examined and interior diameters were measured under the microscope. Results: Our results with artery diameters and lengths were similar with literature. Different from literature, in anterior cerebral artery A1 segment, posterior cerebral artery P1 segment and posterior communicant artery no aplasia were noted. In 50% of the samples, callosomarginal artery were originate from A2 segment. In one case, we observed left and right pericallosal arteries were joined together at the end of the A2 segment and continued as a single pericallosal artery. We could not find any information about this variation in the literature. Conclusion: Before surgical operations, detailed knowledge of Willis polygon and evaluation of the pre-op cerebral angiography considering possible variations, reduce mortality and morbidity ratios. In addition, because of the role of flow gradients of Willis polygon in aneurysm formation, and in terms of better understanding the collateral circulation which is important in vascular occlusive diseases and vascular surgery, we believe, more anatomic studies about this region needed.

Sonographic Development of the Pericallosal Vascularization in the First and Early Second Trimester of Pregnancy.

Anomalies of the corpus callosum are rare. Routine scanning in midtrimester of the pregnancy often fails to identify defective development. The purpose of the study was to identify the pericallosal artery and all its main branching arteries during early gestation from the first trimester onward, to measure the length of the pericallosal artery during its development, and to establish a normal vascular map for each week of development. We performed a single-center prospective, longitudinal clinical study in 15 patients between 11 and 22 weeks of gestation. The origin and course of the different blood vessels were identified. There was a linear association among gestational age, the biparietal diameter, and the length of the pericallosal artery. The curvature of the developing pericallosal artery increases linearly with the gestational age and biparietal diameter, and 4 variations of branching of the callosomarginal artery were observed. The pericallosal artery and its branches can be identified and measured from 11 weeks on, and the pericallosal artery takes its characteristic course. A defective course or an abnormal biometry of the pericallosal artery could be an early sonographic marker of abnormal development of the corpus callosum.

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

ObjectiveCertain 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. MethodsA 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. ResultsThe 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. ConclusionThe 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.

Cerebral Angiographic Study of Anatomical Variations of Anterior Cerebral Artery Complex in Bangladeshi Population

Background: Anterior cerebral artery is an important terminal branch of internal carotid artery. It forms the anterior component of circle of Willis along with the anterior communicating artery. It is known for the frequent variations. The knowledge of anatomical variations in anterior cerebral artery is of considerable help to clinicians and interventionists. Method: Morphology and variations of the anterior cerebral arteries and the anterior communicating artery were studied in 90 patients undergone digital subtraction angiography (DSA).
 Results: Variations were found in 33% (n=30). Variations of the segments in relation with size, course, communications and terminations of the anterior cerebral artery (ACA) were noted. These were divided into different groups like hypoplasia, aplasia, duplication and fenestrations. Hypoplasia/Aplasia of proximal anterior cerebral artery (A1) was 24.5% in right side and 9% in left side. Anterior communicating artery (AComA) was found absent in 9% and fenestration in 9%. Callosomarginal artery was found absent in 2.2% in right side and 4.5% in left side. In right callosomarginal artery 6% had abnormal origin and 3.5% abnormal in left side.Pericallosal artery was present 100% on both sides. Conclusion: Variations of anterior cerebral artery complex anatomy is found common in Bangladeshi population.
 Bangladesh Journal of Neuroscience 2016; Vol. 32 (2): 56-62

Keyhole Cisternal Navigational Resection of an Inner Falx Meningioma

Objective: The keyhole concept in neurosurgery has remained mostly limited to transcranial endoscope-assisted microsurgery or limited-sized keyhole craniotomies. In contrast, documentation of keyhole surgery, as described by Yaşargil, regarding no traumatization to the normal neural, arterial, and venous structures has appeared relatively less in the medical literature, under the term keyhole neurosurgery. Microsurgical resection of falcine meningiomas, although not infrequent, poses technical challenges related to the tumor’s anatomic relationships with the superior sagittal sinus, inferior sagittal sinus, callosomarginal arteries, pericallosal arteries, and neural structures of the medial aspects of the hemispheres. Case Description: A 35-year-old female patient with an anterior inner falcine meningioma and frontal multiple cortical veins draining into superior sagittal sinus is presented. The tumor was totally removed using a very small gap without scarifying any cortical vein. Postoperatively, the patient did very well. Conclusions: The microneurosurgical technique of navigation through aquatic cisternal corridors for surgical access is a minimally invasive technique permitting surgical manipulations through very small gaps and preserves normal neural and vascular structures.

Combined total aortic arch replacement associated with aortic valve replacement and subtotal thyroidectomy

The aim of this study is to present a 57-year-old female patient in whom a combined total aortic arch replacement associated with aortic valve replacement and subtotal thyroidectomy was simultaneously performed. The patient was admitted to the Department of Neurology due to isolated seizure of the right upper limb, with progression of the paresis. The symptoms resolved after a few hours. Seven months earlier, the patient suffered from a haemorrhagic stroke in the right hemisphere due to an aneurysm of the distal branch of the callosomarginal artery. The pathology was then treated by embolisation of the aneurysm. During current hospitalisation, diagnostic tests showed goitre, paroxysmal atrial fibrillation, and aortic valve insufficiency. Computed tomography angiography confirmed aortic dissection — Stanford type A, with dissected aortic arch, brachiocephalic trunk, both common carotid arteries, and the left subclavian artery (Figs. 1, 2). After completed diagnostics, the patient was transferred to the Department of Cardiac Surgery for immediate operation. It was decided to perform a combined aortic valve replacement with total aortic arch replacement and subtotal thyroidectomy. Longitudinal skin incisions on the neck were performed to expose both carotid arteries. Median sternotomy was performed. Brachiocephalic trunk and the right atrium were cannulated. Extracorporeal circulation (ECC) was established and the patient was cooled to 28oC. The aorta was clamped, aortotomy was performed, and Calafiore blood cardioplegia was introduced into the coronary ostia. Aortic valve was replaced using a 21-mm bioprosthesis. Proximal anastomosis with a four-branched graft to the ascending aorta was performed. The selective antegrade cerebral perfusion started, and under circulatory arrest the distal part of the graft was anastomosed with the descending aorta above the left subclavian artery, also using a felt strip and Bio-Glue (Fig. 3). Circulation was restored through the graft. The four-branched graft was anastomosed with both common carotid arteries and the right subclavian artery. Due to dissection of the right internal carotid artery, the vessel was separately reconstructed. During reperfusion and rewarming, a subtotal thyroidectomy was performed (Fig. 4). The surgery took 7 h 10 min, ECC-time was 3 h 22 min, aortic cross clamp time was 1 h 57 min, and circulatory arrest time was 30 min. The postoperative period passed uneventfully. The patient, in a haemodynamically and respiratorily stable state, was discharged 12 days after the surgery to the Department of Cardiology for further rehabilitation. The simultaneous surgical procedures can be safely done after meticulous preparation and diagnostics as well as good constipated surgery sequence. It has to be stated, however, that it requires an individual approach in an environment of an experienced surgical team.

Following the canyon to reach and remove olfactory groove meningiomas.

Olfactory groove meningiomas (OGMs) represent approximately 10% of all intracranial meningiomas. They arise in the olfactory fossa, a variable depression delimited by the lateral lamella and perpendicular plate. The cribriform plate with the lateral lamella and ethmoidal and orbital roof could be viewed as a 'canyon' with the frontal sinus as the main entrance. Between January 2000 and December 2013, 32 consecutive patients underwent removal of OGMs through this 'canyon' at the Department of Neurosurgery of Brescia and Turin. Complete removal was achieved in all patients with this trans-frontal sinus subcranial approach (Simpson grade I; mean lesion volume, 46.6 cm3). Five patients (15.6%) experienced nasal CSF leakage, treated with external lumbar drain positioning for 4 days and resolved in all cases but one, which was re-operated. Two patients (6.2%) during the CSF leakage experienced meningitis at day 7 after surgery, both successfully treated by intravenous antibiotic therapy. After one month, one patient developed hydrocephalus, treated with a ventricular peritoneal shunt. In one patient, traction on the OGM caused bleeding of the callosomarginal artery, which was coagulated with superior frontal gyrus ischemia without neurological consequences. Glasgow Outcome Scale Score at 6 months was V in 29 patients, IV in one patient, and I in two patients. Advantages with this approach may include easy and early control of blood supply from its insertion in the skull base, minimal frontal lobe retraction, preservation of the frontal veins draining to the sagittal sinus, and a satisfactory aesthetic outcome.

Microsurgical anatomy of the central lobe.

The central lobe consists of the pre- and postcentral gyri on the lateral surface and the paracentral lobule on the medial surface and corresponds to the sensorimotor cortex. The objective of the present study was to define the neural features, craniometric relationships, arterial supply, and venous drainage of the central lobe. Cadaveric hemispheres dissected using microsurgical techniques provided the material for this study. The coronal suture is closer to the precentral gyrus and central sulcus at its lower rather than at its upper end, but they are closest at a point near where the superior temporal line crosses the coronal suture. The arterial supply of the lower two-thirds of the lateral surface of the central lobe was from the central, precentral, and anterior parietal branches that arose predominantly from the superior trunk of the middle cerebral artery. The medial surface and the superior third of the lateral surface were supplied by the posterior interior frontal, paracentral, and superior parietal branches of the pericallosal and callosomarginal arteries. The venous drainage of the superior two-thirds of the lateral surface and the central lobe on the medial surface was predominantly through the superior sagittal sinus, and the inferior third of the lateral surface was predominantly through the superficial sylvian veins to the sphenoparietal sinus or the vein of Labbé to the transverse sinus. The pre- and postcentral gyri and paracentral lobule have a morphological and functional anatomy that differentiates them from the remainder of their respective lobes and are considered by many as a single lobe. An understanding of the anatomical relationships of the central lobe can be useful in preoperative planning and in establishing reliable intraoperative landmarks.

Review of the Anatomy of the Distal Anterior Cerebral Artery and Its Anomalies.

The anterior cerebral artery (ACA) varies considerably and this complicates the description of the normal anatomy. The segmentation of the ACA is mostly agreed on by different authors, although the relationship of the pericallosal and callosomarginal arteries (CmA) is not agreed upon. The two basic configurations of the ACA are determined by the presence or absence of the CmA. The diameter, length and origin of the cortical branches have been measured and described by various authors and display great variability. Common anomalies of the ACA include the azygos, bihemispheric, and median anterior cerebral arteries. A pilot study was done on 19 hemispheres to assess the variation of the branches of the ACA. The most common variations included absence and duplication. The inferior internal parietal artery and the CmA were most commonly absent and the paracentral lobule artery was the most frequently duplicated (36.8%). The inferior internal parietal artery originated from the posterior cerebral artery in 40.0% and this was the most unusual origin observed. It is important to be aware of the possibility of variations since these variations can have serious clinical implications. The knowledge of these variations can be helpful to clinicians and neurosurgeons. The aim of this article is to review the anatomy and variations of the anterior cerebral artery, as described in the literature. This was also compared to the results from a pilot study.

前大脳動脈末梢部動脈瘤の手術アプローチに関する検討

Distal anterior cerebral artery aneurysms (DACA-ANs) are relatively uncommon and lead to some unique operative difficulties. We retrospectively reviewed 18 cases of DACA-ANs, treated in our institute between April 2007 and October 2013, with regard to anatomical features and surgical approaches. DACA-ANs were categorized into three groups: infra-, anterior-, and supra-genu types, based on their anatomical relationship with the genu of the corpus callosum.The most common location was the bifurcation of the pericallosal and callosomarginal arteries (50%). DACA-ANs were infra- in 5, anterior- in 11, and supra- genu in 2 cases. The interhemispheric approach (IHA) was selected in all cases except in one. DACA-ANs were clipped via the basal, anterior, and superior IHA in 5, 11, and 1 cases, respectively. Selection of microsurgical trajectory to the aneurysm based on the anatomical architecture of the ACA and genu of the corpus callosum is vital to occlude aneurysms safely with proximal control established.

Saccular trilobed aneurysm of azygos anterior cerebral artery

Multiple saccular or giant aneurysms of azygos anterior cerebral artery (AACA) at the distal segments A2-A5 are very rarely reported. Distal anterior cerebral artery (DACA) aneurysms represent approximately 2%-7% of all cerebral aneurysms. We present the case of an Albanian 62-year-old male, admitted at our service after sudden onset of severe headache and vomiting. Computerized tomography (CT) of the head showed hemorrhage in the front of corpus callosum. CT angiography followed by digitally subtracted angiography (DSA) documented a large necked aneurysm with three lobes at the origin of calloso-marginal artery and a single DACA, also known as AACA. A frontal parasagittal craniotomy was performed. Obliteration of the aneurysm was done only by separate clipping of each three lobes at the respective neck. Postoperative DSA demonstrated complete exclusion of the aneurysm and a regular flow of AACA. The patient recovered uneventfully. Despite it is a rare occurrence, an aneurysm of distal segments of anterior cerebral artery A2-A5, concomitant to AACA should be studied with DSA. In the era of embolization, conserving good microsurgical skills is fundamental for dealing with multilobar cerebral aneurysms, associated with rare anatomical variations.

Diagnostic dyspraxia by disrupted fiber connections of the posterior corpus callosum after distal anterior cerebral artery aneurysm rupture

Dear Editor, We would like to report a well-documented case of diagnostic dyspraxia as a consequence of a ruptured distal anterior cerebral artery (DACA) aneurysm. Radiological findings on tractography permit a better understanding of the physiopathology and anatomo-clinical correlations between diagnostic dyspraxia and intracranial hemorrhage secondary to a DACA aneurysm rupture. A right-handed patient presented with brutal onset of left temporal headache. Clinical examination revealed a Glasgow Coma Scale of 14 with a right crural hemiparesis. The cerebral CT scan showed a subarachnoid hemorrhage Fisher grade IV (Fig. 1a), with the majority of the blood in the pericallosal cistern. The angio-CT demonstrated a right A2 aneurysm at the pericallosal—callosomarginal junction; this was treated immediately by urgent endovascular coiling with no periprocedural complications. On day 1, the patient complained about the feeling of oppositional behavior from his non-dominant hand against his dominant hand. The left hand-dissociative movements were triggered by voluntary activities of his right hand: when we asked the patient to take an object with his right hand, his left hand seized the object before the right hand had time to reach it. The patient never doubted that the left hand was part of his own body, and he had no left/right hand confusion, but he felt that his left hand had its own will. No frontal release signs such as grasping or perseverance were observed. Neuropsychological testing showed language difficulties and clinical signs of callosal disconnection (bilateral taping disturbance, interdigital transfer difficulties, left tactile extinction) associated with executive dysfunction. In the subacute phase, T2and DWI-weightedMRI images showed involvement of the body and splenium of the corpus callosum with residual blood in the pericallosal cistern (Fig. 1b). The tractographic analysis confirmed the interhemispheric disconnection at the posterior third of the corpus callosum with a complete interruption of the commissural fibers (Fig. 1c, d). The patient underwent a specialized rehabilitation and had a good recovery with a complete return to autonomous daily life activities. DACA aneurysms account for about 3 to 7 % of intracranial aneurysms, most of which commonly arise at the bifurcation of the pericallosal and calloso-marginal arteries [3]. Ruptured DACA aneurysms are smaller than in other sites and are associated with more frequent intracerebral hematomas [4]. The Alien Hand Syndrome (AHS) was first described by Goldstein as a variety of clinical conditions whose common characteristic is the uncontrolled behavior or the feeling of strangeness of one extremity, most frequently involving the left hand [1, 2]. The common classification distinguishes between the posterior, or sensory form, of AHS and the anterior, or motor form, of this condition. To explain inconsistencies such as the phenomenon of diagonistic dyspraxia, Aboitiz (2003) proposed the distinction of five classes of AHS with peculiar clinical manifestations and specific anatomical substrates [1]. G. Cossu (*) :M. Messerer : R. T. Daniel Departement des Neurosciences Cliniques, Service de Neurochirurgie, Centre Hospitalier Universitaire Vaudois, Universite de Medecine et Biologie de Lausanne, Rue du Bugnon 44, 1011 Lausanne, Switzerland e-mail: giulia.cossu@chuv.ch

Traumatic Aneurysm of the Callosomarginal Artery-Cortical Artery Junction from Penetrating Injury by Scissors

Traumatic intracranial aneurysms (TICAs) are rare and are associated with high rates of morbidity and mortality. TICAs usually result from head injuries caused by traffic accidents, industrial accidents, or gunshots. We report a traumatic aneurysm of the callosomarginal artery-cortical artery junction arising from a penetrating injury by scissors. A 51-year-old woman was admitted to our hospital after suffering a penetrating injury caused by scissors. Computed tomography (CT) and CT-angiography demonstrated a right orbital roof fracture, subarachnoid hemorrhage, frontal lobe hemorrhage, intraventricular hemorrhage, and a traumatic aneurysm of the right callosomarginal artery-cortical artery junction. We trapped the traumatic aneurysm and repositioned a galeal flap. Postoperative CT showed a small infarction in the left frontal lobe. Follow-up angiography two months later showed no residual aneurysm. We suggest that an aggressive surgical intervention be performed whenever TICA is diagnosed.

Prenatal Demonstration of Normal Variants of the Pericallosal Artery by 3D Ultrasound

To demonstrate the different normal variants of the fetal pericallosal artery (PCA) with the different branching forms of callosomarginal artery (CMA) by three-dimensional glass body-rendering. With the use of the glass body mode (grey scale ultrasound and color or power Doppler), 3-D ultrasound permits precise imaging of the fetal pericallosal artery, an important anatomic landmark of the corpus callosum. This rendering mode enabled us for the first time to demonstrate sonographically the origin, course and branching pattern of the pericallosal artery with the callosomarginal artery. In 452 fetus between 18 and 41 weeks of gestation 5 variants of branching of the fetal A. callosomarginalis from the pericallosal artery were found using three-dimensional ultrasonography. The CMA was absent in 36.06 % of the 452 fetal brains studied. In 63.94 % the CMA was present and arose from four different segments of the anterior cerebral artery (ACA) from the A3 segment in 59.17 %, from the A2 segment in 20.7 %, from the A4 segment in 13.15 % and from the A1 segment in 7.61 % of the cases. The use of 3-D power Doppler sonoangiography enables the precise demonstration of the normal variants of the fetal pericallosal artery with different origins of the callosomarginal artery. The knowledge of normal variants helps to detect pathological forms of the pericallosal artery.

Coil embolization of ruptured frontopolar artery aneurysm: Case report

Distal anterior cerebral artery aneurysms are infrequent. The most common location is at the bifurcation of the pericallosal and callosomarginal arteries. Cerebral artery anomalies can sometimes, at least partially, explain aneurysm formation in less common locations in relation to hemodynamic stress caused on the vascular wall. We report a very rare case of subarachnoid hemorrhage due to a ruptured frontopolar artery aneurysm as a part of an anomalous anterior cerebral artery complex that was, for the first time, treated with endovascular coiling.

Endovascular Management of Distal ACA Aneurysms: Single-Institution Clinical Experience in 22 Consecutive Patients and Literature Review

Distal ACA aneurysms remain difficult to treat with endovascular therapy, but improved technology and experience allows for the treatment of some of these aneurysms with excellent results. The purpose of this study was to assess the status of endovascular treatment of distal ACA aneurysms by comparing our results with recent endovascular and microsurgical series of distal ACA aneurysms. Between 2000 and 2008, a total of 22 consecutive patients (14 women; mean age, 58.4 years) with distal ACA aneurysms underwent coil placement at Barrow Neurological Institute. Clinical presentations, radiographic findings, endovascular management, and outcomes were reviewed retrospectively. Of the 22 patients, 13 (59%) presented with subarachnoid hemorrhage. Six patients were HH grade I or II, 1 was grade III, 5 were grade IV, and 1 was grade V. Frontal lobe hematomas occurred in 5 patients with ruptured aneurysms. The mean aneurysm size was 7.5 mm (range, 2.8-25 mm); 55% were smaller than 7 mm. Twelve aneurysms (55%) arose from the origin of the callosomarginal artery (55%). Complete occlusion was achieved in 50% of the cases and near-complete occlusion in 45%. The few periprocedural complications included 1 retroperitoneal hematoma and 1 intraoperative rupture. Four patients had thromboembolic events adequately treated intraprocedurally with abciximab. No deaths occurred in the patients treated. The characteristics of the patients and aneurysms treated in our series were comparable to previous reports of endovascular treatment of ACA aneurysms with respect to rupture status. Periprocedural morbidity and mortality rates in our series fared well compared with previous reports, as did our combined rate of complete or near-complete occlusions. Recent advances in endovascular devices and techniques have improved outcomes of distal ACA aneurysms.

Microsurgical anatomy of the anterior cerebral artery in Indian cadavers

The microanatomy features of cerebral arteries may be variable and may be different in different ethnic groups. To study the anterior cerebral artery (ACA) anatomy in North-West Indian cadavers. Microanatomy features of the ACA were studied in 15 formalin fixed human cadaveric brains under microscope. The outer diameter, length, and number of perforating branches with respective anomalies were measured for each of the following vessels: ACA (proximal A1 segment to distal A2 segment), anterior communicating artery (ACoA), Recurrent artery of Heubner (RAH), and callosomarginal artery and photographed for documentation. The mean length and external diameter of right and left A1 segment was 12.09 mm and 12.0 mm and 2.32 mm and 2.36 mm respectively. Narrowing, duplication, and median ACA were seen in 6.6%, 3.3% and 6.6% of the vessels respectively. Complex ACoA type was seen in 40% cadavers. RAH originated at an average point of 0.2 mm distal to ACoA, but in one cadaver it arose 5 mm proximal to ACoA. Double RAH was found in 26.6%. The course of RAH in relation to A1 was superiorly in 60%, in anteriorly 30% and posteriorly in 10% of cadavers. The orbitofrontal artery (OFA) and frontopolar artery (FPA) arose from A2 in 83.3% to 40% respectively. The mean distance of OFA and FPA from ACoA was 4.17 mm and 8.5 mm respectively. After giving rise to central, callosal and cortical branches, pericallosal artery terminated near the splenium of the corpus callosum or on the precuneus as the inferomedial parietal artery. Knowledge of the microvascular anatomy is indispensable and it is mandatory to be aware of the possible variations in the anomalies to minimize morbidity.

The Contralateral Transcingulate Approach

The contralateral transcingulate approach is a variation of the contralateral transcallosal approach for lesions located in the cingulate gyrus and deep white matter of the medial frontal lobe. To more thoroughly describe the contralateral transcingulate approach by reporting our operative technique and results. This approach positions the head with the midline horizontally, lesion on the upside, allowing gravity retraction of the dependent frontal lobe. Bifrontal craniotomy and splitting of the interhemispheric fissure create a crossing trajectory from the contralateral fissure to the ipsilateral cingulate gyrus that maximizes lateral exposure. Eleven patients with vascular lesions were treated with the contralateral transcingulate approach (9 patients with cavernous malformations and 2 patients with arteriovenous malformations). Eight lesions were located on the left side, 5 in the cingulate gyrus, and 6 in the deep frontal lobe. The falx was cut in 5 patients to extend the crossing trajectory. All lesions were removed completely, with neurological morbidity in 1 patient caused by venous infarction. Although similar to the contralateral transcallosal approach, the contralateral transcingulate approach accesses lesions outside the ventricle and has a steeper crossing trajectory. This approach requires no disruption of brain tissue with lesions on the cingulate surface and only a small incision in cingulate gyrus with lesions in the deep frontal lobe. The ipsilateral pericallosal and callosomarginal arteries provide dependable landmarks for transcingulate dissection. The contralateral transcingulate approach offers an alternative medial approach to lesions near language and motor areas and avoids lateral transcortical approaches, awake speech mapping, and risk to eloquent cortex in the dominant hemisphere.

Clip assisted use of gelatin–thrombin matrix sealant as a rescue procedure to treat a hidden arterial tear

Major intracranial arteries can be injured during tumor removal. Surgeons routinely manage this event by using either microvascular direct repair, by-pass of the wounded segment or the placement of a sutureless device. These procedures, however, are not always possible due to artery brittleness, deep operating field, vascular configuration, or restricted viewing field. In this particular case, we illustrate an example of innovative use of gelatin–thrombin matrix sealant used to repair a hidden tear of pericallosal–callosomarginal bifurcation. A 49-year-old man underwent resection of a recurrent left frontal glioma. During an attempt to remove a firmly attached portion of the tumor, a tear occured in the pericallosal–callosomarginal bifurcation. The wall defect was repaired with a temporary vascular clip placed on the pericallosal artery and gelatin–thrombin matrix sealant sprayed over the tear. An intraoperative indocyanine videoangiography showed patency of both the pericallosal and callosomarginal arteries. Gelatin–thrombin matrix sealant is useful to control bleeding from an artery when the viewing field is restricted. In some cases, however, blood outflow must first be reduced in order to allow clot formation.

The azygos anterior cerebral artery bypass: double reimplantation technique for giant anterior communicating artery aneurysms

The authors introduce the azygos anterior cerebral artery (ACA) bypass as an option for revascularizing distal ACA territories, as part of a strategy to trap giant anterior communicating artery (ACoA) aneurysms. In this procedure, the aneurysm is exposed with an orbitozygomatic-pterional craniotomy and distal ACA vessels are exposed with a bifrontal craniotomy. The uninvolved contralateral A(2) segment of the ACA serves as a donor vessel for a short radial artery graft. The contralateral pericallosal artery (PcaA) and the callosomarginal artery (CmaA) are connected to the graft in the interhemispheric fissure using the double reimplantation technique. Three anastomoses create an azygos system supplying the entire ACA territory, enabling the surgeon to trap the aneurysm incompletely. Retrograde flow from the CmaA supplies the ipsilateral recurrent artery of Heubner, and the aneurysm lumen thromboses. The azygos bypass was successfully performed to treat a 47-year-old woman with a giant, thrombotic ACoA aneurysm supplied by the A(1) segment of the left ACA, with left PcaA and CmaA originating from the aneurysm base. The authors conclude that the azygos ACA bypass is a novel option for revascularizing PcaA and CmaA, as part of the overall treatment of giant ACoA aneurysms.