The diagnostic accuracy of MRI in determining the relations between paraclinoid aneurysms and the cavernous sinus.

PURPOSE: The location of paraclinoid aneurysms is determinant for evaluation of its intradural compartment and risk of SAH after rupture. Advanced MRI techniques have provided clear visualization of the distal dural ring (DDR) to determine whether an aneurysm is intracavernous, transitional or intradural for decision-making. We analyzed the diagnostic accuracy of MRI in predicting whether a paraclinoid aneurysm is intracavernous, transitional or intradural. METHODS: We conducted a prospective cohort between January 2014 and December 2018. Patients with paraclinoid aneurysms underwent 3D fast spin-echo MRI sequence before surgical treatment. The DDR was the landmark for MRI characterization of the aneurysms as follow: (i) Intradural; (ii) Transitional; and (iii) Intracavernous. The MRI sensitivity, specificity, positive and negative likelihood ratios were determined compared to the intraoperative findings. We also evaluated the intertechnique agreement using the Cohen's kappa coefficient (κ) for dichotomous classifications (cavernous vs non-cavernous). RESULTS: Twenty patients were included in the cohort. The accuracy of MRI showed a sensitivity of 86.7% (95%CI:59.5-98.3) and specificity of 90.0% (95%CI:55.5-99.8). Analyzing only patients without history of SAH, accuracy test improved with a sensitivity of 92.3% (95%CI:63.9-99.8) and specificity reached 100% (95%CI: 63-100). Values of Cohen's kappa (κ), intertechnique agreement was considered substantial for dichotomous classifications (κ = 0.754; p < 0.001). For patients without previous SAH, intertechnique agreement was even more coincident for the dichotomous classification (κ = 0.901; p < 0.001). CONCLUSION: 3D fast spin-echo MRI sequence is a reliable and useful technique for determining the location of paraclinoid aneurysms in relation to the cavernous sinus, particularly for patients with no history of SAH.

Cerebral arteriovenous malformation and foreign accent syndrome: a case report.

OBJECTIVE: This case study aims to present the Foreign Accent Syndrome (FAS) in a patient with Cerebral Arteriovenous Malformation (cAVM), considering neuropsychological, radiological and microsurgical aspects. METHODS: The patient underwent preoperative neuropsychological assessment and MRI and Tractography were performed to identify fibers close to the lesion site. In the surgical procedure, a craniotomy was performed for excision of the cAVM. After surgery and 6 months after the surgical procedure, the patient underwent further and neuropsychological evaluations. RESULTS: The presence of AVM located in the posterior part of the medial surface of the left superior frontal gyrus was identified and the neuropsychological evaluation found cognitive deficits and symptoms characteristic of FAS, which disappeared after resection. CONCLUSION: This report presented a case of cAVM in which symptoms were found even without rupture, which was no longer observed after the surgical procedure, demonstrating the relationship of cAVM with the symptoms and neuroanatomical bases of FAS.

Unusual Spinal Foraminal Hemangioblastoma With Prominent Arteriovenous Shunt.

Von Hippel-Lindau (VHL) disease is a rare neurocutaneous disorder characterized by multiple benign and malignant tumors involving different organs (renal, adrenal, pancreas, liver, urogenital system, central nervous system, and head and neck region) due to mutations in the VHL tumor suppressor gene. Here, we describe a patient with unknown VHL disease who has complained of hypoesthesia of the right lower limb for about six years. A lumbar MRI was performed and revealed an expansive foraminal lesion at the right L3-L4 level and multiple serpiginous intradural and extramedullary flow voids involving the dorsal aspect of the spinal cord. The patient underwent digital subtraction angiography to exclude a spinal dural arteriovenous fistula, which revealed imaging features suggestive of spinal hemangioblastoma. In the presence of a spinal hemangioblastoma, a brain MRI was performed for further evaluation to rule out the possible diagnosis of VHL disease, and a solitary hemangioblastoma on the right cerebellar hemisphere was found. The patient underwent lumbar spine surgery, confirming the suspicious diagnosis of hemangioblastomas related to VHL disease.

Microsurgery for a medial left giant lesser sphenoid wing meningioma complicated by postoperative vasospasm of the ipsilateral supraclinoid carotid artery.

Background: Sphenoid wing meningiomas present close contact with intracranial arteries and have great potential for vascular complications. Here, we describe the case of a patient who presented a medial left giant lesser sphenoid wing meningioma involving the supraclinoid carotid artery. One week after surgery, she developed vasospasm whose treatment using milrinone achieved excellent results. Case Description: This is the case of a 23-year-old female with a large meningioma of the middle third of the lesser wing of the left sphenoid. Furthermore, the patient had symptoms of headache, diplopia, and left amaurosis (Video 1). The lesion involved the supraclinoid left carotid artery, causing significant stenosis of the vessel. The patient underwent surgical treatment without complications. One week after the procedure, she evolved with lowered level of consciousness, complete, and proportionate right hemiparesis and right Babinski's sign. Angiographic study demonstrated significant stenosis of the left supraclinoid artery. After endovascular treatment with milrinone, the patient evolved with immediate improvement of signs and symptoms.Video 1:Surgical procedure. Video is accessible from the portal. Conclusion: Giant meningiomas with vascular involvement involve a higher risk of postoperative vascular complications. Other studies should be carried out to predict these complications and thus develop preventive measures.

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).

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 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.

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.

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.

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.

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.

Microsurgical Treatment of Ruptured Spetzler-Martin Grade 3 Right Hippocampal Arteriovenous Malformation: 3-Dimensional Operative Video.

We present a 14-yr-old male with a history of traumatic brain injury in March 2016, secondary to clonic tonic generalized seizures. CT scan showed hemorrhage at mesial temporal region in the body of right hippocampus, intraventricular hemorrhage at the level of lateral ventricles (right and left side) and fourth ventricle. After this the patient presented with pulsating right temporal headache of high intensity (VAS 10/10) that improved with common analgesics, dizziness, and clonic tonic generalized seizures despite taking Phenobarbital 100 mg/24 h. Neuropsychological assessment reveal major deficits regarding executive functions: working memory, verbal fluency, and planning abilities. Brain MRI and angiography showed AVM at the right level of hippocampus body. An intranidal aneurysm was also observed. Venous drainage was through the basal vein of Rosenthal. We planned for surgery and resection of the hippocampal AVM through the trans-T2 approach. Postoperatively, the patient was without medical complications. We present a 3-dimensional video of the microsurgical treatment for right hippocampal AVM performed through a trans-T2 approach. 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.

Reproducibility of a new classification of the anterior clinoid process of the sphenoid bone.

BACKGROUND: Pneumatization of the anterior clinoid process (ACP) affects paraclinoid region surgery, this anatomical variation occurs in 6.6-27.7% of individuals, making its preoperative recognition essential given the need for correction based on the anatomy of the pneumatized process. This study was conducted to evaluate the reproducibility of an optic strut-based ACP pneumatization classification by presenting radiological examinations to a group of surgeons. METHODS: Thirty cranial computer tomography (CT) scans performed from 2013 to 2014 were selected for analysis by neurosurgery residents and neurosurgeons. The evaluators received Google Forms with questionnaires on each scan, DICOM files to be manipulated in the Horos software for multiplanar reconstruction, and a collection of slides demonstrating the steps for classifying each type of ACP pneumatization. Interobserver agreement was calculated by the Fleiss kappa test. RESULTS: Thirty CT scans were analyzed by 37 evaluators, of whom 20 were neurosurgery residents and 17 were neurosurgeons. The overall reproducibility of the ACP pneumatization classification showed a Fleiss kappa index of 0.49 (95% confidence interval: 0.49-0.50). The interobserver agreement indices for the residents and neurosurgeons were 0.52 (0.51-0.53) and 0.49 (0.48-0.50), respectively, and the difference was statistically significant (P < 0.00001). CONCLUSION: The optic strut-based classification of ACP pneumatization showed acceptable concordance. Minor differences were observed in the agreement between the residents and neurosurgeons. These differences could be explained by the residents' presumably higher familiarity with multiplanar reconstruction software.

Anterior temporal artery to posterior cerebral artery bypass for revascularization of the posterior circulation: An anatomical study.

We describe a novel intracranial-to-intracranial bypass technique between the anterior temporal artery and the posterior cerebral artery for revascularization of the posterior circulation. Four formalin-fixed human heads were examined to demonstrate the detailed anatomy of the middle cerebral artery and the posterior cerebral artery, and to illustrate the step-by-step bypass procedure. The anterior temporal artery, a branch of the middle cerebral artery, can be anastomosed to the P2 segment of the posterior cerebral artery as an alternative to extracranial bypass donor segments for treatment of complex aneurysms requiring revascularization. The anastomosis of the anterior temporal artery as a pedicled donor to the posterior cerebral artery provides a shorter graft, due to its close anatomical position to the posterior cerebral artery, for posterior circulation revascularization.