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1/120. Tentorial dural arteriovenous fistula obliterated using the petrosal approach.

    BACKGROUND: Tentorial dural arteriovenous fistulas (AVFs) are uncommon lesions usually treated surgically using a subtemporal exposure with division of the tentorium. This exposure requires significant retraction of the temporal lobe and has the possibility of significant arterialized venous bleeding if a draining vein is accidentally cut during division of the tentorium. skull base surgical techniques may provide alternate approaches for the surgical treatment of tentorial dural AVFs. methods: A tentorial dural arteriovenous fistula supplied by the tentorial artery and drained by the petrosal vein was exposed and obliterated using the petrosal (subtemporal-presigmoid) approach. RESULTS: The petrosal approach allowed the exposure and division of the superior petrosal sinus and tentorium with direct visualization of the supratentorial and the infratentorial compartments, avoiding accidental damage to the draining veins. The dural fistula was easily obliterated after its venous drainage was interrupted and the tentorial artery occluded. CONCLUSIONS: Tentorial dural AVFs can be safely treated with interruption of the venous drainage. The exposure can be enhanced with a petrosal approach, decreasing the possibility of uncontrolled bleeding during the procedure.
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ranking = 1
keywords = visual
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2/120. An angiographically occult arteriovenous malformation in the medial parietal lobe presenting as seizures of medial temporal lobe origin.

    We present an unusual case of a patient who was diagnosed with temporal lobe epilepsy and whose seizures were reduced markedly after excision of an angiographically occult arteriovenous malformation (AVM) located in the left medial parietal lobe. A 38-year-old man had complex partial seizures characterized by motionless staring with oroalimentary and behavioral automatisms since the age of 15 years. magnetic resonance imaging (MRI) demonstrated a small lesion extending from the left posterior cingulate gyrus to the precuneus. There was no MRI evidence of mesial temporal sclerosis. Intracranial EEG recordings showed ictal onset from the left medial parietal lobe propagating to the medial temporal lobes. Clinical signs appeared when these discharges reached the temporal lobes. After excision of the lesion (which was histologically confirmed as an AVM), together with the marginal cortex, seizures were reduced significantly. Careful diagnostic evaluation of lesions such as the this one may reveal an epileptogenic lesion (zone) far from the region where scalp ictal discharges seem to arise. In our case, we hypothesize that false localization was due to propagation of ictal discharges from the parietal focus through the limbic system.
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ranking = 15.551556450406
keywords = cortex
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3/120. Endoscopic procedures for resection of arteriovenous malformations.

    BACKGROUND: Resection of arteriovenous malformations (AVMs), particularly those located in functional areas, requires precision. To enhance that precision, endoscope-assisted microsurgery has been employed at loma Linda University. methods: Twenty-five consecutive cases of AVM were treated microsurgically with endoscopic assistance. patients were divided into two groups: (1) those having AVMs in functional areas, and (2) those whose AVMs extended into the ventricle, either in the trigonal area or the capsulocaudatothalamic area. The endoscope was inserted into the subarachnoid space to interrupt communicating venules around the major draining vein and into the cleavage developed between the AVM venous loops and surrounding brain tissue as shunting arterioles and communicating venules were interrupted. For surgery of intraventricular AVMs, the curved endoscope was inserted into the ventricle, providing visualization of the AVM core, which was dissected from the ventricular side. RESULTS: AVMs were totally resected in all cases except for two patients with capsulocaudatothalamic AVMs, which were decreased in size sufficiently to receive radiosurgery. CONCLUSION: Endoscope-assisted microsurgery enhances magnification, illumination, and technical precision while the surgeon is dissecting the AVM core vessels and while operating on AVMs extending into the ventricle.
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ranking = 1
keywords = visual
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4/120. Impaired capacity of cerebellar patients to perceive and learn two-dimensional shapes based on kinesthetic cues.

    This study addresses the issue of the role of the cerebellum in the processing of sensory information by determining the capability of cerebellar patients to acquire and use kinesthetic cues received via the active or passive tracing of an irregular shape while blindfolded. patients with cerebellar lesions and age-matched healthy controls were tested on four tasks: (1) learning to discriminate a reference shape from three others through the repeated tracing of the reference template; (2) reproducing the reference shape from memory by drawing blindfolded; (3) performing the same task with vision; and (4) visually recognizing the reference shape. The cues used to acquire and then to recognize the reference shape were generated under four conditions: (1) "active kinesthesia," in which cues were acquired by the blindfolded subject while actively tracing a reference template; (2) "passive kinesthesia," in which the tracing was performed while the hand was guided passively through the template; (3) "sequential vision," in which the shape was visualized by the serial exposure of small segments of its outline; and (4) "full vision," in which the entire shape was visualized. The sequential vision condition was employed to emulate the sequential way in which kinesthetic information is acquired while tracing the reference shape. The results demonstrate a substantial impairment of cerebellar patients in their capability to perceive two-dimensional irregular shapes based only on kinesthetic cues. There also is evidence that this deficit in part relates to a reduced capacity to integrate temporal sequences of sensory cues into a complete image useful for shape discrimination tasks or for reproducing the shape through drawing. Consequently, the cerebellum has an important role in this type of sensory information processing even when it is not directly associated with the execution of movements.
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ranking = 3
keywords = visual
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5/120. Stereotactic radiosurgery and particulate embolization for cavernous sinus dural arteriovenous fistulae.

    OBJECTIVE: To evaluate the safety and efficacy of stereotactic radiosurgery, either with or without transarterial embolization, in the treatment of patients with dural arteriovenous fistulae (DAVFs) of the cavernous sinus. methods: We reviewed the findings, from a prospectively established database, for 20 patients with cavernous sinus DAVFs who were treated with either radiosurgery alone (n = 7) or radiosurgery and transarterial embolization (n = 13) in a 7-year period. The median follow-up period after radiosurgery was 36 months (range, 4-59 mo). RESULTS: Nineteen of 20 patients (95%) experienced improvement of their clinical symptoms. Fourteen of 15 patients (93%) experienced either total (n = 13) or nearly total (n = 1) obliteration of their DAVFs, as documented by angiography performed a median of 12 months after radiosurgery. No patient experienced a recurrence of symptoms after angiography showed DAVF obliteration. Two patients developed new neurological deficits after embolization procedures. One patient exhibited temporary aphasia secondary to a venous infarction; another patient exhibited permanent VIth cranial nerve weakness related to acute cavernous sinus thrombosis. Two patients experienced recurrent symptoms and underwent repeat transarterial embolization at 7 and 12 months; both patients achieved clinical and angiographic cures (5 and 10 mo later, respectively). One patient experienced recurrent visual symptoms and underwent transvenous embolization 4 months after radiosurgery. CONCLUSION: Staged radiosurgery and transarterial embolization provided both rapid symptom relief and long-term cures for patients with cavernous sinus DAVFs. radiosurgery alone was effective for patients with DAVFs whose arterial supply was not accessible via a transarterial approach, although the time course of symptom improvement was longer, compared with patients who also underwent embolization.
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ranking = 1
keywords = visual
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6/120. Orbital drainage from cerebral arteriovenous malformations.

    OBJECTIVE: To describe the neuro-ophthalmic findings in patients with orbital drainage from cerebral arteriovenous malformations (AVMs). methods: We reviewed the records of 100 consecutive adult patients with cerebral AVMs who presented to our institution during a 4-year period. All patients with orbital drainage were identified, and their neuro-ophthalmic evaluations were reviewed. RESULTS: Three patients (3%) were identified with orbital drainage from a cerebral AVM. The first patient presented with typical chiasmal syndrome (reduced visual acuity, bitemporal hemianopia, and optic atrophy). magnetic resonance imaging demonstrated a large left temporal and parietal lobe AVM with compression of the chiasm between a large pituitary gland and a markedly enlarged carotid artery. The second patient presented with headaches and postural monocular transient visual obscurations. Examination revealed normal visual function with minimal orbital congestion and asymmetrical disc edema, which was worse in the left eye. magnetic resonance imaging revealed a large right parietal and occipital lobe AVM without mass effect or hemorrhage and an enlarged left superior ophthalmic vein. The third patient had no visual symptoms and a normal neuro-ophthalmic examination; a right parietal lobe AVM was discovered during an examination for the cause of headaches. CONCLUSION: Orbital drainage from cerebral AVMs is rare. Manifestations may include anterior visual pathway compression, dilated conjunctival veins, orbital congestion, and asymmetrical disc swelling.
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ranking = 5
keywords = visual
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7/120. prenatal diagnosis of an aneurysm of the vein of Galen with three-dimensional color power angiography.

    The prenatal diagnosis of an aneurysm of the vein of Galen has been reported on only a few occasions. This rare arterio-venous fistula is suspected when an intracerebral hypoechoic cyst is found in which blood flow can be demonstrated by Doppler ultrasound. This is one of the few conditions where Doppler ultrasound is critical for the diagnosis. Three-dimensional color power Doppler (3D-CPA) is a recent ultrasound modality which enables the three-dimensional visualization of vessels and which is more readily available than magnetic resonance imaging (MRI) We report a fetus in which an aneurysm of the vein of Galen was detected at 33 weeks' gestation and where the application of 3D-CPA enabled a better understanding of the spatial orientation and course of the dilated vessels. The neonate was successfully treated with coil angiography but subsequently died at 5 months of age from cardiac decompensation. Where fetal malformations involve the vascular system, 3D-CPA appears to be a promising technique.
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ranking = 1
keywords = visual
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8/120. language mapping in pretreatment planning of patients with cerebral arteriovenous malformation: a PET study.

    PURPOSE: Three patients who had cerebral arteriovenous malformations underwent language mapping by positron emission tomography (PET) to identify the dominant hemisphere for language and the spatial relation of lesions to language areas. methods: Mapping was performed to assess the risk that surgery could cause neurologic deficits and to plan other therapeutic strategies. RESULTS: The information obtained by PET language mapping changed the course of management for these patients. Two patients were treated with stereotactic radiosurgery and one patient with surgical resection. CONCLUSIONS: PET imaging can be a valuable noninvasive tool for mapping the functional cortex and for preoperative planning of different treatment options in patients with arteriovenous malformations.
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ranking = 15.551556450406
keywords = cortex
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9/120. Surgery or gamma -knife for the treatment of arteriovenous malformations?

    decision making for either surgery or gamma-knife for the treatment of arteriovenous malformations (AVMs) cannot be uniform. The skill of the neurosurgeon in operating on AVMs is now being compared with that of the gamma-knife. The decision varies from case to case and is to be taken by the neurosurgeon. This report presents three cases in which such decision making was not easy. Case 1 was a non-ruptured cingulate AVM of 2.5 cm diameter in the cingulate cortex. The operative field was anticipated to be very narrow between the parietal bridging veins. Case 2 was a tiny ruptured AVM in the speech-motor area which was buried underneath the cortex. Case 3 was a large ruptured thalamo-stiriate-capsular AVM with feeders from the anterior and posterior choroidal arteries. All cases were operated without serious morbidity. A combination of pre-operative intravascular surgery (cases 1 and 3) or postoperative gamma-knife (case 3) was adopted. In conclusion, there is no unitary rule to decide on surgery or gamma-knife for the treatment of AVMs. It depends on what good or harm the responsible surgeon or the gamma-knife does.
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ranking = 31.103112900812
keywords = cortex
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10/120. Cerebral arteriovenous malformation presenting as visual deterioration in a child.

    A rare case of visual loss as the presenting feature of a central arteriovenous malformation involving the vein of Galen is reported. A 5-year-old girl with a history of deteriorating vision for the past 6 months was examined. Ocular examination showed a left hemianopia, left optic atrophy, and dilated vessels of the right optic disc. MRI revealed a massive deep-seated central arteriovenous malformation involving the vein of Galen. The mechanism of visual loss is likely to be a combination of ischaemic optic atrophy associated with a steal phenomenon and direct compression of the right optic radiation.
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ranking = 6
keywords = visual
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