Recurrent Artery of Heubner Guiding the Clip Application for Internal Carotid Artery Bifurcation Aneurysm: 2-Dimensional Operative Video.

Aneurysms of the bifurcation of the internal carotid artery (ICA) represent approximately 5% of intracranial aneurysms and tend to occur in younger patients.1-3 They typically have a superior orientation, in close relationship with the medial (branches of the anterior cerebral artery, segment A1) and lateral (branches of the middle cerebral artery, segment M1) lenticulostriate arteries (LSA), including recurrent artery of Heubner (RAH). RAH commonly originates in the junction of A1 and A2, courses medially to laterally between LSA and anterior cerebral artery, ICA bifurcation, and middle cerebral artery before entering the lateral portion of the anterior perforated substance.4-7 Damage to these arteries are catastrophic. This complex vascular anatomy makes treatment challenging, either endovascular or microsurgical.8-13 We present a video case of microsurgical clipping for the left ICA bifurcation aneurysm. This study was approved by the ethics committee of our institution. The patient, a 46-year-old man, was diagnosed with an unruptured ICA bifurcation aneurysm during workup for intermittent headache. Morphological characteristics of the aneurysm supported intervention over conservative treatment. Digital subtraction angiography showed a prominent proximal RAH crossing between the aneurysm neck and LSA, providing anatomical protection for clip application. Microsurgical clipping was chosen, and the procedure went uneventfully. The patient consented to the procedure and to the publication of his/her image. We discussed and demonstrated throughout the video how we used this anatomic variation and trajectory of the RAH to prevent clipping of LSA unwittingly and achieve complete occlusion of the aneurysm neck.

Case report: Association between PTEN-gene variant and an aggressive case of multiple dAVFs.

Introduction: Mutations of the phosphatase and tensin homolog (PTEN) gene have been associated with a spectrum of disorders called PTEN hamartoma tumor syndrome, which predisposes the individual to develop various types of tumors and vascular anomalies. Its phenotypic spectrum includes Cowden syndrome (CS), Bannayan-Riley-Ruvalcaba syndrome (BRRS), Proteus syndrome, autism spectrum disorders (ASD), some sporadic cancers, Lhermitte-Duclos disease (LDD), and various types of associated vascular anomalies. Clinical presentation: A previously healthy 27-year-old woman was experiencing visual scintillating scotomas and mild chronic headaches for the past 2 years. The initial computed tomographic (CT) and magnetic resonance imaging (MRI) scans did not reveal any abnormalities, but the possibility of pseudotumor cerebri was considered. Furthermore, a cerebral angiogram showed a posterior fossa dural arteriovenous fistula (dAVF), which was initially treated through embolization. However, in spite of proper treatment, this patient experienced multiple recurrent dAVFs in different locations, requiring multiple embolizations and surgeries. Despite exhibiting altered cerebral perfusion and hemodynamics, the patient did not display any significant symptoms until she experienced a sudden stroke resulting from deep venous thrombosis, which was not associated with any medical procedures or medication use. A comprehensive analysis was performed due to the aggressive nature of the dAVFs. Surprisingly, exome sequencing of a blood sample revealed a PTEN gene variant in chromosome 10, indicative of Cowden syndrome. However, no tumors or other vascular lesions were detected in other systems that would constitute Cowden syndrome. Conclusion: The rapid formation of multiple and complex dAVFs, coupled with not meeting the criteria for any other PTEN-related syndrome, unequivocally leads to the presentation of a novel phenotype of the PTEN germline variant.

Case report: Delayed outflow obstruction of a DVA: A rare complication of brainstem cavernoma surgery.

Introduction: Developmental venous anomalies (DVAs) are considered variants of normal transmedullary veins. Their association with cavernous malformations is reported to increase the risk of hemorrhage. Expert consensus recommends meticulous planning with MR imaging, use of anatomical "safe zones", intraoperative monitoring of long tracts and cranial nerve nuclei, and preservation of the DVA as key to avoiding complications in brainstem cavernoma microsurgery. Symptomatic outflow restriction of DVA is rare, with the few reported cases in the literature restricted to DVAs in the supratentorial compartment. Case: We present a case report of the resection of a pontine cavernoma complicated by delayed outflow obstruction of the associated DVA. A female patient in her 20's presented with progressive left-sided hemisensory disturbance and mild hemiparesis. MRI revealed two pontine cavernomas associated with interconnected DVA and hematoma. The symptomatic cavernoma was resected via the infrafacial corridor. Despite the preservation of the DVA, the patient developed delayed deterioration secondary to venous hemorrhagic infarction. We discuss the imaging and surgical anatomy pertinent to brainstem cavernoma surgery, as well as the literature exploring the management of symptomatic infratentorial DVA occlusion. Conclusion: Delayed symptomatic pontine venous congestive edema is extremely rare following cavernoma surgery. DVA outflow restriction from a post-operative cavity, intraoperative manipulation, and intrinsic hypercoagulability from COVID-10 infection are potential pathophysiological factors. Improved knowledge of DVAs, brainstem venous anatomy, and "safe entry zones" will further elucidate the etiology of and the efficacious treatment for this complication.

The Intersection Between the Oculomotor Nerve and the Internal Carotid Artery to Distinguish Extracavernous and Intracavernous Paraclinoid Aneurysms Using Anatomic Dissections-A New 3T Magnetic Resonance Imaging Protocol Confirmed by Three-Dimensionally Printed Biomodels.

OBJECTIVE: To evaluate the relationship between the oculomotor nerve (CNIII) and the internal carotid artery (ICA) as a new anatomic-radiologic landmark for distinguishing the exact location of a paraclinoid intracranial aneurysm (IA). METHODS: Microanatomic dissections were performed in 20 cavernous sinuses to evaluate the ICA paraclinoid region. Based on anatomic observations, a new magnetic resonance (MRI) protocol to classify paraclinoid aneurysms was proposed. MRI of 42 IAs from 34 patients was independently analyzed and classified as intracavernous, extracavernous, or transitional by 2 neuroradiologists. To validate the proposed MRI protocol, each IA was classified by a three-dimensionally (3D) printed biomodel and agreement with the radiologic classifications was evaluated. Of 42 IAs, 23 undergoing microsurgeries were also classified by direct visualization. RESULTS: We observed that the true cavernous sinus roof is defined by the carotid-oculomotor membrane, which has an intimate relationship with the intersection between the superior limit of the CNIII and the ICA. Based on this intersection, all 42 IAs were radiologically classified and agreement with the 3D printed biomodels was observed in 95% IAs. Concordance tests showed a statistically significant (P < 0.05) agreement between the classifications. All 23 IAs treated had the radiologic and 3D biomodel classification confirmed. CONCLUSIONS: The intersection between the ICA and the CNIII, which crosses it transversely in its entire diameter, is a reliable anatomic-radiologic landmark to correctly classify paraclinoid aneurysms. Through a new MRI protocol, it is possible to radiologically identify this intersection and to easily distinguish the intracavernous and extracavernous ICA paraclinoid aneurysms.

Tips and Tricks in Microsurgical Treatment for Previously Embolized Aneurysms-Three-Dimensional Video.

One of the most popular treatment strategies for complex cerebral aneurysms with wide necks is stent-assisted coiling.1 Although it is a minimally invasive technique, it is associated with higher recurrence rates (approximately 20%) compared with surgical clipping.2 Recanalization is more common principally in ruptured aneurysms as well as in giant aneurysms, aneurysms located in the posterior circulation, aneurysms with a relatively wide neck morphology, and aneurysms followed for >1 year.2-6 Tirakotai et al. classified the indications for surgical treatment after coiling into 3 groups: 1) surgery of incompletely coiled aneurysms; 2) surgery for mass effects on neural structures; 3) surgery for vascular complications.7 Recanalization, if significant, often requires retreatment. Retreating with additional coils fails in perhaps 50% of cases.3 On the other hand, surgical clipping is complicated and difficult to perform. Recanalized aneurysms are categorized into 3 types: type I, coils are compressed; type II, coils are migrated; type III, coils are migrated, and multiple coils fill its neck or the parent artery. Direct clipping can be applied to types I and II, whereas trapping, wrapping, or auxiliary revascularization is required in type III.2 Coil extraction should not be attempted regularly because it is associated with high morbidity.8 In this three-dimensional video, we present the microsurgical treatment of a type I recanalized anterior communicating artery aneurysm, which in serial digital subtraction angiography control scans showed residual patency, progressive growth, and changes in its hemodynamic behavior (Video).

Awake Microsurgical Resection for a Precentral Gyrus Arteriovenous Malformation-Three-Dimensional Video and Anatomic Landmarks.

Arteriovenous malformations (AVMs) are complex, heterogeneous, and uncommon neurovascular disorders that frequently manifest in young adults. Parenchymal AVMs are thought to be congenital, but this has been recently questioned in the literature.1,2 AVMs can change over time and cause focal neurological signs or neurocognitive deficits.3 The clinical presentation of an AVM is variable and depends mainly on the occurrence of bleeding as well as its location, size, and ability to take flow from adjacent areas.4 AVMs can be treated by a single modality or a combination of different modalities. According to the Expert Consensus on the Management of Brain Arteriovenous Malformations, neurosurgery may be the best option for Spetzler-Martin grade 2 AVMs.5 However, the treatment of these lesions when located in eloquent areas, especially in the central lobe, is controversial. Awake craniotomy allows identification of eloquent gyrus and can potentially facilitate resection with functional preservation. An alternative is stereotactic radiosurgery, but a qualitative comparative analysis revealed higher obliteration rate with awake AVM excision compared with stereotactic radiosurgery.6 Awake craniotomy was the earliest surgical procedure known, and it has become fashionable again. It was used in the past for surgical management of intractable epilepsy, but its indications are increasing, and it is a widely recognized technique for resection of mass lesions involving the eloquent cortex and for deep brain stimulation.7 Its application for resection of vascular lesions, including AVMs, is still limited. In the Video, we present a case of a cerebral AVM of the precentral gyrus in which we achieved complete resection with awake microsurgical treatment without any neurological sequelae for the patient.

Microsurgical Treatment for Arteriovenous Malformation in Eloquent Area: A 2-Dimensional Surgical Video and Step-by-Step Practical Guide.

Cerebral arteriovenous malformations (AVMs) are dynamic neurovascular disorders that occur mainly in young adults, presenting an annual risk of rupture of 2% - 4% per year.1 They can be asymptomatic, representing an incidental radiologic finding, or present with neurologic deficits according to their brain location, size, and presence or absence of bleeding.2,3 AVMs located in eloquent areas4 represent a great challenge for neurosurgeons, sometimes directed to alternatives therapies (e.g., embolization, radiotherapy) due to the difficulty in planning and surgical technique. Despite the complexity, we consider that there is benefit to removing these lesions; this can be done safely, as with the adequate microsurgical strategy and neuroanatomic knowledge. In Video 1, we show the case of a 55-year-old male patient with an AVM positioned over the right central sulcus. He presented with intermittent left-hand paresthesia followed by an episode of involuntary movements in the left arm without loss of consciousness and with spontaneous resolution. Angiography showed an AVM feed by branches of the middle cerebral artery and multiple venous drainage for the Trolard complex and superficial middle cerebral vein, with a 4-cm nidus, making it grade III in the Spetzler-Martin classification.4 The patient underwent surgery with total resection of the lesion without any complication or new neurologic deficits.

Microsurgical Treatment for a Cerebral Arteriovenous Malformation of the Central Sulcus.

Arteriovenous malformations (AVMs) are congenital neurovascular disorders frequently manifested in young adults. The clinical presentation is variable and depends on its location, size, and ability to steal flow from adjacent areas, but it depends mainly on the occurrence of bleeding.1 The treatment of these lesions when located in eloquent areas, especially around the central sulcus, is controversial. Surgical resection of an AVM in the central lobe may cause postoperative sensorimotor deficits because this anatomic region includes the precentral and postcentral gyri on the lateral surface and paracentral lobule on the medial surface.2 AVMs can be successfully treated by surgery, but this treatment may pose unacceptable risks to the patient if the AVM involves an eloquent cortex. We consider that surgical removal of many of these lesions is feasible when preoperative planning is performed,3 when it is based on deep anatomic knowledge, and particularly when using a refined microsurgical technique.1 In this 3-dimensional Video 1, we present a case of a cerebral AVM of the central sulcus in which we achieved complete resection with microsurgical treatment without any neurologic sequelae for the patient. The patient consented to publication of images.

Microsurgical Treatment for a Ruptured Posterior Inferior Cerebellar Artery Aneurysm: A 3-Dimensional Surgical Video and Anatomic Landmarks Review.

Aneurysms are the most frequent issue for the posterior inferior cerebellar artery (PICA). PICA aneurysms account for 1.4% to 4.5% of all intracranial aneurysms.1-3 Although the majority of PICA aneurysms arise from their junction with the vertebral artery, they can be found in any of 5 segments.4,5 Although PICA is more prone to form nonsaccular aneurysms than other intracranial arteries, ruptured aneurysms are usually saccular.6 Nearly all PICA aneurysms are located intracranially, above the foramen magnum. Extracranial PICA aneurysms are rare, with few reports in literature.7 Microsurgical clipping remains a good treatment alternative for these aneurysms. Higher risk of rerupture has even been reported with embolization of the distal PICA aneurysm with parent artery preservation.8 Here we present the case of a 64-year-old male patient who presented right after a thunderclap headache, followed by a temporary loss of consciousness and disorientation. He was diagnosed with a modified Fisher 4 and Hunt and Hess 2 subarachnoid hemorrhage and found to have a partially thrombosed left PICA saccular aneurysm of the caudal loop just below the foramen magnum. The lesion was approached via a midline suboccipital craniotomy with C1 laminectomy. Microsurgical clipping of the aneurysm was performed without any complications (Video 1). Postoperatively, the patient was discharged without neurologic deficits. We present the first surgical video of the necessary steps in order to perform a microsurgical clipping of an extracranially located caudal loop PICA aneurysm through a midline suboccipital craniotomy with C1 laminectomy.

Awake Microsurgical Resection for Optochiasmatic Cavernous Malformation.

Cavernous malformations (CM) affect approximately 0.5% of the population, with only a limited portion being located in the optic nerve and chiasma. The clinical presentation is determined by their locations. In the optochiasmatic CM, the acute visual disturbance is the most common presentation. Chronically, many show a progressive visual loss, chronic headache, and pituitary disturbances. The differential diagnosis includes optic glioma, arteriovenous malformations, aneurysm, craniopharyngioma, pituitary apoplexy, and inflammatory conditions. In Video 1, we present the case of a 39-year-old woman with a history of a hemorrhagic optochiasmatic cavernoma in 2016, who started using propranolol to reduce the lesion and symptoms of visual loss. Moreover, the first microsurgical resection of the cavernoma and evacuation of the hematoma were performed in the same year. Owing to evolvement from a partial to a total vision loss in the left eye and presentation of new symptoms in the right eye, the patient underwent microsurgical resection. The surgery was performed sequentially. An awake craniotomy was performed to monitor the chiasma and right optic nerve. The postoperative magnetic resonance imaging showed complete resection of the CM, and the patient fully recovered. The patient signed the institutional consent form, stating that he or she accepts the procedure and allows the use of his or her images and videos for any type of medical publications in conferences and/or scientific articles.

Microsurgical Treatment for Posthemorrhagic Cavernoma of Frontal Lobe Coexisting with Unruptured Ipsilateral Middle Cerebral Artery Aneurysm.

Cerebral cavernous malformations, also known as cavernomas, are vascular abnormalities of the brain that are clinically associated with a variety of neurologic symptoms that may include hemorrhagic strokes. They are the most common vascular abnormality, representing 10%-25% of all vascular malformations.1 Lesions associated with cavernomas include developmental venous anomalies, capillary telangiectasias, and other vascular malformations2 but not intracranial aneurysms. The latter association is extremely rare; in fact, there is only 1 case reported in the literature, in which the cavernoma was obscured by the presence of a cerebral hemorrhage and an unruptured aneurysm, which was presumed to be the primary cause of the bleeding, thereby misleading the surgeons to treat only the aneurysm.2 There are different alternatives for the management of different types of lesions.3-5 In this 3-dimensional operative video (Video 1), we present a case of a cavernoma associated with hemorrhage coexisting with an unruptured aneurysm in which we achieved complete resolution of both with microsurgical treatment through a pterional approach.6 The patient consented to publication of images.

Combined treatment for a hemispheric cerebellar AVM.

Posterior fossa arteriovenous malformations (AVMs) can be a challenging disease, especially those large in size. AVMs can be treated with a combination of endovascular treatment and microsurgery. Here, the authors present the case of a 16-year-old female patient with progressive dizziness and episodic syncope. The workup of the patient showed a hemispheric cerebellar AVM, Spetzler-Martin grade IV. She underwent combined treatment (endovascular and microsurgery) with no complications and cure of the malformation. The video can be found here: https://youtu.be/rNw_Kyd76Mg.

Transtentorial Approach for Parahippocampal Gyrus Arteriovenous Malformation Resection: 3-Dimensional Operative Video.

Medial temporal basal arteriovenous malformations (AVMs) have complex anatomy. They usually drain to the basal vein of Rosenthal, and arterial feeders can arise from the anterior choroidal artery and its branches, or from the posterior cerebral artery. If the AVM is more posterior in the parahippocampal gyrus, there is a predominance of arterial feeders arising from P2P or P3 segments of the posterior cerebral artery. As posterior AVMs are difficult to reach using anterior approaches, the supracerebellar transtentorial approach provides a direct pathway to the malformation, allowing better visualization and exposure of the vascular anatomy. In this video, we present a 29-yr-old woman with a left parahippocampal AVM with P2P arterial feeders and Rosenthal basal vein drainage. The patient had three months of moderate headache and two abrupt seizures before admission. Emergency computed tomography showed intraventricular hemorrhage. Magnetic resonance imaging and cerebral angiography revealed an AVM located in the parahippocampal gyrus, posterior to pulvinar thalamus. The patient underwent microsurgical treatment in semi-sitting position using a supracerebellar and infratentorial approach with transtentorial resection. The AVM was completely removed, and the patient recovered without neurological deficits. The authors present a 3-dimensional video of the microsurgical steps required to perform a transtentorial approach for AVM resection in the parahippocampal gyrus. The patient signed the Institutional Consent Form, which allows the use of his/her images and videos for any type of medical publications in conferences and/or scientific articles.

Awake Craniotomy for Removal of Left Insular Cavernous Malformation.

The insula plays a crucial role in speech planning due to its connections with cortical and subcortical areas. Surgical management of cavernous malformation (CM) of the insula consists of total resection of the lesion and the surrounding gliosis to avoid or reduce seizures. When located in the dominant hemisphere, an awake craniotomy with intraoperative mapping reduces the risk of functional damage. The insula is covered by the operculum and has a relationship with the middle cerebral artery and its branches that run along its lateral surface. Therefore high expertise is required to manage the exposure of the insula and its complex anatomy. This video demonstrates the surgical management of a large left insular CM. A 29-year-old female with multiple CM and 7 years of partial seizures and recent onset of short memory loss. Neuroimaging showed a large left insular and planum polare CM with important mass effect and hemorrhage signs. The patient consented to surgery, and an awake pretemporal craniotomy was carried out with continuous motor evoked potential monitoring. No language function was localized in the superior temporal gyrus; therefore corticectomy of the middle portion was performed to expand the operative corridor. The vessel manipulation during wide opening of the sylvian fissure increased the risk of postoperative vasospasm and blood drain into the surgical field. The CM was exposed and completely removed without functional damage. The patient recovered from surgery without complications, and no seizures occurred at 2 months' follow-up. Postoperative imaging showed complete removal of the CM.

Microsurgical Clipping of Low-Riding Basilar Bifurcation Aneurysm.

Basilar bifurcation is a challenging site for aneurysm clipping. Anatomical factors such as size and projection of the aneurysm, distance between the aneurysm neck and the dorsum sellae, and location of the basilar bifurcation contribute to surgical complexity. Endovascular treatment has been used more frequently than microsurgical clipping, especially for posterior circulation lesions. Thus, the upcoming generation of neurosurgeons will have increasingly less access to the microsurgical treatment of such lesions. We present the case of a 45-year-old female patient who presented sudden mental confusion characterized by disorientation in time, space, and person. Investigative acute cerebral magnetic resonance imaging revealed diffusion restriction in the left posterior cerebral and superior cerebellar arteries. The clinical and cardiologic investigations revealed no abnormalities, but computed tomographic angiography and digital arteriography revealed a low-riding basilar bifurcation aneurysm and a very small aneurysm in the right internal carotid artery. The wide neck precluded coil embolization, and the appropriate stent was not covered by our public health insurance. Considering the young age, surgical treatment was proposed. Microsurgical clipping was performed using the right pre-temporal approach. In this two-dimensional video, we show the steps to reach the low-riding basilar bifurcation aneurysm neck. The positioning, transzygomatic pterional craniotomy, intradural anterior clinoidectomy, and posterior cavernous sinus opening are shown, and the surrounding anatomy is illustrated.

Anaplastic Ganglioglioma of the Pineal Region ­ A Case Report

Introduction Gangliogliomas are tumors commonly found in the temporal lobe and related to seizures; their appearance in the pineal region is rarely described. This report characterizes the first case of anaplastic ganglioglioma of the pineal region. Case Report The authors describe the case of a 32-year-old woman that developed progressive headache. An MRI investigation revealed a pineal tumor. The patient tested negative for biomarkers and underwent surgery through supracerebellar infratentorial approach and achieved gross total resection of the tumor in a challenging location. Pathological analysis revealed a biphasic neoplasm with the following two distinct phenotypes in separate fields: an immature neuronal component with several atypical mitoses and a mature astrocytic component with bipolar cells, microcysts, and eosinophilic bodies. The Ki67/MIB1 proliferation index was 20­30% in localized hotspots. Based on the pathological findings, the tumor was defined as an anaplastic ganglioglioma World Health Organization (WHO) grade III. Discussion/Conclusion Gangliogliomas are classified as glioneural neoplasms based on the histologic findings described as a mixture of neoplastic astrocytes and neurons. Moreover, these tumors represent 0.4­1.3% of tumors of the central nervous system. Authors describe de novo anaplastic ganglioglioma as 1% of the largest series. Gross total resection and adjuvant treatment may play important role in patients' prognostic. In this case, due to the malignant anaplastic component of her tumor, the patient received treatment with temozolamide and radiotherapy after gross total resection of the lesion.

Introdução Gangliogliomas são tumores comumente encontrados no lobo temporal e se relacionam com crises epilépticas; o aparecimento desses tumores na região da pineal é raramente descrito. Este relato caracteriza o primeiro caso de ganglioglioma anaplásico da região da pineal. Relato de Caso Paciente do sexo feminino, 32 anos, apresentou-se com cefaleia de piora progressiva. Investigação com ressonância magnética revelou tumor na região da pineal. Os biomarcadores para tumores da pineal foram negativos e a paciente foi submetida a microcirurgia com o acesso supracerebelar e infratentorial atingindo ressecção total da lesão. A análise patológica revelou neoplasia bifásica com dois fenótipos distintos em campos separados: um componente era composto por células neuronais imaturas com inúmeras mitoses atípicas e o segundo componente era composto por astrócitos maduros, microcistos e corpos eosinofílicos. Foi encontrado um índice proliferativo Ki67/M1B1 de 20­30%. Baseado nos achados anatomopatológicos, o tumor foi definido como ganglioglioma anaplásico grau III da OMS. Discussão/Conclusão Gangliogliomas são classificados como neoplasias glioneurais baseado nos achados histológicos descritos como misto de neoplasia neuronal e glial; esses tumores representam 0,4­1,3% de todos os tumores do sistema nervoso central. Ganglioglioma anaplásico de novo tem sido descrido em 1% nas maiores series de gangliogliomas. Ressecção total da lesão e tratamento adjuvante desempenham um papel importante no prognóstico dos pacientes. Devido ao componente anaplásico do tumor em questão, a paciente foi tratada com temozolamida e radioterapia após ressecção total da lesão.