Migration of lipiodol into lateral ventricles after embolization of cerebral arteriovenous malformation: a case report.

N-butyl cyanoacrylate (NBCA) has been used to embolise brain arteriovenous malformations (AVMs) for over 30 years. It is a mixed with lipiodol in varying proportions. We report a 22-year-old male with intraventricular hemorrhage from a ruptured intranidal AVM aneurysm in the left temporal lobe. The intranidal aneurysm and the nidus were successfully embolized using a 20% NBCA and lipiodol mixture without any complications according to computed tomography (CT) immediately after treatment. Scattered high-density spots were observed in both lateral ventricles on CT 5 days after embolization, suggesting migration of lipiodol. We speculated that the aneurysm was a pseudoaneurysm whose wall protruded into the inferior horn of the left lateral ventricle, and the lipiodol in the NBCA migrated into the ventricles after the thin part of the wall ruptured. The patient developed pyrexia due to chemical meningitis, which responded to steroid treatment for one month.

Stereotactic radiosurgery for arteriovenous malformations of the basal ganglia and thalamus: an international multicenter study.

OBJECTIVE: Arteriovenous malformations (AVMs) of the basal ganglia (BG) and thalamus are associated with elevated risks of both hemorrhage if left untreated and neurological morbidity after resection. Therefore, stereotactic radiosurgery (SRS) has become a mainstay in the management of these lesions, although its safety and efficacy remain incompletely understood. The aim of this retrospective multicenter cohort study was to evaluate the outcomes of SRS for BG and thalamic AVMs and determine predictors of successful endpoints and adverse radiation effects. METHODS: The authors retrospectively reviewed data on patients with BG or thalamic AVMs who had undergone SRS at eight institutions participating in the International Gamma Knife Research Foundation (IGKRF) from 1987 to 2014. Favorable outcome was defined as AVM obliteration, no post-SRS hemorrhage, and no permanently symptomatic radiation-induced changes (RICs). Multivariable models were developed to identify independent predictors of outcome. RESULTS: The study cohort comprised 363 patients with BG or thalamic AVMs. The mean AVM volume and SRS margin dose were 3.8 cm3 and 20.7 Gy, respectively. The mean follow-up duration was 86.5 months. Favorable outcome was achieved in 58.5% of patients, including obliteration in 64.8%, with rates of post-SRS hemorrhage and permanent RIC in 11.3% and 5.6% of patients, respectively. Independent predictors of favorable outcome were no prior AVM embolization (p = 0.011), a higher margin dose (p = 0.008), and fewer isocenters (p = 0.044). CONCLUSIONS: SRS is the preferred intervention for the majority of BG and thalamic AVMs. Patients with morphologically compact AVMs that have not been previously embolized are more likely to have a favorable outcome, which may be related to the use of a higher margin dose.

Recurring Thalamic Symptoms Due to Intracranial Dural Arteriovenous Fistula: Report of Unusual Case and Treatment Outcome.

BACKGROUND: Initial clinical presentation of dural arteriovenous fistula (DAVF) with predominantly thalamic symptoms is rare and has not been reported until now. CASE DESCRIPTION: A young child presenting with complaints of tinnitus and mild right hemiparesis was evaluated with an initial magnetic resonance imaging, which revealed a Borden type 2 DAVF in the right transverse sinus with retrograde venous drainage and cortical venous reflux. Flow-related small aneurysms were also noted in the left basal vein of Rosenthal (BVR). Two days later, his motor power deteriorated and he developed right hemisensory loss and severe thalamic pain. Aphasia was atypical and mimicked the transcortical type. Repeat imaging revealed expanding thrombosed aneurysm of BVR with mass effect and edema on thalamocapsular region. Initial antiedema measures reversed the neurologic deficits; however, they recurred, necessitating an urgent endovascular intervention. Angiogram revealed an extensive high-flow DAVF in the right transverse-sigmoid sinus and torcula with preferential retrograde venous drainage into deep veins and left BVR. He underwent staged embolization of DAVF, resulting in significant obliteration of shunt. Neurologic deficits improved in the postoperative period, and the patient remained clinically asymptomatic at 6 months of follow-up. CONCLUSIONS: DAVF presenting with recurrent predominantly thalamic symptoms is rare. Atypical transcortical aphasia rather than fluent aphasia is an unusual clinical manifestation of thalamic pathology and could result from the involvement of specific thalamic nuclei. Preferential high flow into BVR in the presence of venous anomalies could potentially induce architectural weakness of the venous wall and precipitate aneurysm formation. Embolization of the DAVF can potentially reverse this unusual neurologic condition.

Bilateral Thalamic Edema from Coexisting Choroid Plexus Arteriovenous Malformation and Sinus Thrombosis: Case Report.

Bilateral thalamic dysfunction secondary to venous congestion may result from either venous sinus thrombosis or high flow arteriovenous malformations or a combination of both. We present a case of bilateral thalamic edema resulting from concomitant choroid plexus arteriovenous malformation (AVM) and straight sinus thrombosis and describe our treatment approach. The patient presented with several weeks of progressive confusion and memory deficits. Magnetic resonance imaging and venography (MRI/ MRV) showed bilateral thalamic T2 hyperintensities and straight sinus thrombosis. Subsequent cerebral angiography revealed a choroid plexus AVM within the right lateral ventricle. The patient underwent surgical resection of the AVM resulting in postoperative resolution of bilateral thalamic edema on MRI and improvement of his confusion and memory deficits. This case demonstrates a rare example of reversible bilateral thalamic edema secondary to venous hypertension from both an AVM and sinus occlusion after appropriate treatment of the AVM.

Delayed symptomatic haemorrhage from the remnants of a thalamic arteriovenous malformation after previous angiographic cure with radiotherapy.

In 1995 a 16-year old girl was diagnosed with a large left thalamic AVM that was considered unsuitable for microsurgical resection and was treated with radiotherapy twice, which led to angiographic cure. She re-presented 19 years after initial treatment with a symptomatic acute thalamic haemorrhage. Her digital subtraction angiography was negative for arterio-venous shunting. MRI/MRA showed cystic change with adjacent contrast enhancement in the region of the previously irradiated arteriovenous malformation. The patient underwent an interhemispheric transcallosal resection of the left thalamic haemorrhagic lesion via a contralateral craniotomy. Intra-operatively there was a cystic cavity filled with blood products in association with thrombosed, calcified vessels as well as actively filling vessels. Histologically there were aggregated abnormal blood vessels with a dilated lumen and surrounded by brain parenchyma. Some of the vessel walls were thickened with fibrosis and some were arterialised with presence of elastin fibres. Potential mechanisms for the delayed haemorrhage are discussed.

Bilateral Thalamic Edema from Coexisting Choroid Plexus Arteriovenous Malformation and Sinus Thrombosis: Case Report.

Bilateral thalamic dysfunction secondary to venous congestion may result from either venous sinus thrombosis or high flow arteriovenous malformations or a combination of both. We present a case of bilateral thalamic edema resulting from concomitant choroid plexus arteriovenous malformation (AVM) and straight sinus thrombosis and describe our treatment approach. The patient presented with several weeks of progressive confusion and memory deficits. Magnetic resonance imaging and venography (MRI/ MRV) showed bilateral thalamic T2 hyperintensities and straight sinus thrombosis. Subsequent cerebral angiography revealed a choroid plexus AVM within the right lateral ventricle. The patient underwent surgical resection of the AVM resulting in postoperative resolution of bilateral thalamic edema on MRI and improvement of his confusion and memory deficits. This case demonstrates a rare example of reversible bilateral thalamic edema secondary to venous hypertension from both an AVM and sinus occlusion after appropriate treatment of the AVM.

Dural arteriovenous fistula (D-AVF): a rare cause of symmetrical bithalamic changes with free diffusivity changes.

We report a rare case of an encephalopathic presentation of a posterior fossa dural arteriovenous fistula with concomitant florid symmetrical bithalamic free diffusivity changes on MRI in a previously healthy individual. We describe the structural and functional imaging findings and the role of catheter angiography in diagnosis, prognostication and the timing and strategy in the management of this challenging vascular entity.

Thalamic arteriovenous malformation fed by the artery of Percheron originating from the contralateral posterior cerebral artery in a child.

PURPOSE: Artery of Percheron (AOP) is a rare variant of thalamoperforating artery with a single common trunk feeding both thalami and with or without contribution to the rostral midbrain. We report the first case of thalamic arteriovenous malformation (AVM) fed by AOP with hemorrhagic onset. METHODS: A 12-month-old girl suddenly weakened and developed coma. Left thalamic hemorrhage was detected with the third and both lateral ventricles' hematoma. Thalamic AVM was discovered to be fed by an AOP originating from the contralateral posterior cerebral artery. RESULTS: Endovascular embolization of AVM was impossible due to a risk of bilateral thalamic infarction and anatomical inaccessibility. Thalamic AVM was removed by high superior parietal approach without new neurological symptoms. CONCLUSION: The first case of thalamic AVM fed by AOP originating from the contralateral posterior cerebral artery is reported. Surgical removal of AVM would be at the heart of treatment in order to avoid bilateral thalamic infarction.

Disseminated intravascular coagulation after craniotomy.

Disseminated intravascular coagulation (DIC) is reported in neurosurgical patients; however, the incidence of DIC after craniotomy procedures is unknown. Using a surgical database, we identified 3164 patients who underwent primary craniotomy at Mayo Clinic Rochester between January 1, 2000 and December 31, 2004. Potential cases of DIC in this population were identified using 3 search triggers, patients: (1) in whom the diagnosis of DIC was noted on their hospital discharge summary, (2) who received red blood cell-free blood products, or (3) in whom a blood fibrinogen or d-dimer concentration was assessed. Using criteria based on laboratory values, we estimated the incidence of DIC developing within 72 hours of primary craniotomy to be between 13 and 44 per 10,000 patients. Despite a low incidence of DIC, the associated mortality rate was 43% to 75%. Traumatic head injury was a significant risk factor for the development of DIC [odds ratio of trauma was in the range of 16 (95% confidence interval (CI)=5.3-49) to 29 (CI=4.0-204)]. Autologous salvaged blood was administered intraoperatively to 44 patients, and 1 of these developed DIC. Although this small sample of patients receiving salvaged blood requires caution in interpreting the results, the risk of DIC seemed to be greater with salvaged blood than without [odds ratio 24 (CI=2.5-237)]. In children, 2 of 3 patients who developed DIC had congenital malformations of the brain. Findings from this study suggest that DIC is rare after craniotomy, but is often associated with mortality.

Hyperbaric oxygen in the treatment of a radiosurgical complication: technical case report.

OBJECTIVE: Hyperbaric oxygenation is a rarely used method of treatment for steroid-refractory radiation-induced edema after stereotactic radiosurgery. We present its successful implementation for a radiosurgical complication after the treatment of a deep, large arteriovenous malformation. We also review the literature on hyperbaric oxygenation for radiation-induced complications. CLINICAL PRESENTATION: A 25-year-old man underwent radiosurgical treatment for a large arteriovenous malformation. Three years later, substantially smaller remaining nidus was retreated. Five months after that treatment, the patient developed edema around the nidus and hemiparesis. This problem was refractory to high-dose steroids. INTERVENTION: The patient underwent a course of 25 hyperbaric oxygenation treatments. Within 1 month, the edema and hemiparesis had improved, allowing steroids to be tapered. A follow-up examination 1 year later revealed complete thrombosis of the arteriovenous malformation and minimal neurological deficit. CONCLUSION: This technical case report adds to the few studies in the literature suggesting that hyperbaric oxygenation therapy, in conjunction with a slow steroid taper, is a reasonable addition to the treatment armamentarium for radiation-induced cerebral edema associated with clinically evident neurological deficits.

[The peculiarities of speech disturbance in patients with arteriovenous malformations of the caudate nucleus and the thalamus].

Clinical and neuropsychological study of 28 patients with arteriovenous malformations (AVM) of the caudate nucleus and 36 patients with AVM of the thalamus has been conducted. After surgical removal of the caudate nucleus, speech disturbances developed in 4 out of 8 patients with left-side AVM and in 1 patient, a converted left-hander, with right-side AVM. All 5 patients had mild speech disturbances, which differed by character in dependence of the AVM location. In case of AVM location in the head of the caudate nucleus, the speech disturbances were represented by perseverations and were similar to those caused by the lesion in the Broca area. In case of the caudate nucleus lesion, naming was mildly affected that resembled temporal aphasia. After surgical removal of AVM in the left thalamus in 9 patients, complex and rather stable speech disturbances developed in 7 cases. They were featured by the signs of frontal and temporal aphasias, i.e. there were perseverations and disturbances of naming, auditory and speech memory. The peculiarities of speech disturbances in lesions of the caudate nucleus and the thalamus were well explained by their anatomic and functional correlations with different regions of brain speech cortex. Speech disturbances in various subcortical lesions are reviewed. In the authors' opinion, subcortical aphasias do not have any particular character but include the same factors in different combinations as cortical ones that is determined by the presence of common functional systems for speech support which comprise cortical and subcortical patterns.

Ventricular/paraventricular small arteriovenous malformations: role of embolisation with cyanoacrylate.

Arteriovenous malformations (AVMs) located in or near to ventricles have proven difficult to treat. We report the safety and efficacy of embolisation of these deep central lesions and describe the contribution of embolisation to multimodality treatment. Fourteen consecutive patients with small (less than 3 cm) ventricular/paraventricular AVMs arranged for possible embolisation to their nidi. All patients presented with intracranial haemorrhage. The AVMs ranged in size from 10 to 30 mm (average, 17 mm). Embolisations were performed using liquid adhesive (cyanoacrylate and iodised oil mixture at a ratio of less than 1:4) delivered by flow-guided microcatheters with the patient under general anaesthesia. One patient (7.1%) was considered unsuitable for embolisation, and another (7.1%) was not able to undergo embolisation because of the morphological features of the AVM feeders, while the remaining 12 could be embolised successfully. Six of 12 patients who underwent embolisation achieved complete occlusion of their AVMs (overall occlusion rate, 42.9%), while the remaining 6 were embolised partially with a 60-95% (mean = 80%) size reduction. One (8%) permanent neurological deficit resulted from embolisation. Endovascular therapy seems to make a significant contribution to the multimodality treatment of small AVMs located in the ventricle or paraventricular deep area. Embolisation alone permits complete cure in a large number of patients. It results in obliteration of a significant volume of the nidus in most of the remaining patients, which makes those nidi more vulnerable to subsequent multimodal therapy.

[A surgical approach to Holmes' tremor associated with high-frequency synchronous bursts]. / Approche chirurgicale d'un tremblement de Holmes associé à un tremblement synchrone de haute fréquence.

INTRODUCTION: The effectiveness of thalamic stimulation is now clearly demonstrated for essential tremor, but remains to be demonstrated for other types of tremor. OBSERVATION: A young woman presented Holmes' tremor resulting from a pontine tegmental hemorrhage related to an arteriovenous malformation. A surgical approach was considered when major functional impairment persisted at 2-year follow-up despite drug therapy. The patient underwent unilateral thalamic deep brain stimulation (Vim); major improvement persisted at eighteen months follow-up. CONCLUSION: This observation is in line with previous reports suggesting that thalamic surgery can be one of the best options for treating medically intractable Holmes' tremor. The mechanism underlying the tremor, implying dentate-rubro-thalamic pathways is discussed. Moreover, the patient exhibited short periods of 16Hz tremor when her arms were maintained outstretched. Thalamic stimulation also appears to be effective for these high-frequency synchronous cerebellar bursts.

Deep arteriovenous malformations of the basal ganglia and thalamus: natural history.

OBJECT: Patients with arteriovenous malformations (AVMs) in a deep location and with deep venous drainage are thought to be at higher risk for hemorrhage than those with AVMs in other locations. Despite this, the natural history of AVMs of the basal ganglia and thalamus has not been well studied. METHODS: The authors retrospectively evaluated a cohort of 96 patients with AVMs in the basal ganglia and thalamus with respect to the tendency of these lesions to hemorrhage between the time of detection and their eventual successful management. The 96 patients studied had a mean age of 22.7 years at diagnosis, and 51% were male. Intracranial hemorrhage (ICH) was the event leading to clinical detection in 69 patients (71.9%), and 85.5% of these patients were left with hemiparesis. After diagnosis, 25 patients bled a total of 49 times. The cumulative clinical follow up after detection but before surgical management was 500.2 patient-years. The risk of hemorrhage after detection of an AVM of the basal ganglia or thalamus was 9.8% per patient-year. CONCLUSIONS: The rate of ICH in patients with AVMs of the basal ganglia or thalamus (9.8%/year) is much higher than the rate in patients with AVMs in other locations (2-4%/year). The risk of incurring a neurological deficit with each hemorrhagic event is high. Treatment of these patients at specialized centers is recommended to prevent neurological injury from a spontaneous ICH.

Scalp arteriovenous malformation draining into the superior sagittal sinus associated with an intracranial arteriovenous malformation: just a coincidence? Case report.

OBJECTIVE AND IMPORTANCE: Recent experimental and clinical evidence suggests that hemodynamic changes in the venous system can induce the formation of new arteriovenous malformations (AVMs). In a rat model, increased venous pressure induces the formation of soft tissue and dural AVMs. We report a clinical observation that may support these data. CLINICAL PRESENTATION: A 4-year-old boy with a midline scalp AVM draining into the superior sagittal sinus had an associated intracranial/parenchymal AVM. The cerebral AVM increased venous pressure in the superior sagittal sinus as revealed by angiography. INTERVENTION: The scalp AVM was resected, and the intracranial AVM was treated by use of the gamma knife. CONCLUSION: On the basis of reported experimental data and the morphological and hemodynamic characteristics in this patient's two lesions, we suggest that the scalp AVM might have been induced by hypertension in the superior sagittal sinus. This clinical observation supports the notion suggested by experimental studies that hemodynamic changes can induce the formation of associated AVMs.

[The unilateral space neglect in patients with arteriovenous malformations of the deep brain structures]. / Fenomenon odnostoronnego prostranstvennogo ignorirovaniia u bol'nykh s arteriovenoznymi mal'formatsiiami glubinnykh struktur golovnogo mozga.

Clinical and neuropsychological study has been carried out in 187 patients with arteriovenous malformations (AVM) of the deep brain structures, including 28 patients with caudate nucleus AVM, 35--with thalamus AVM, 45--with cingulated gyrus AVM, 43--with hippocampus AVM, 36--with corpus callosum AVM. Ignoring phenomenon in different modalities has been found in 47 patients, 40 patients having unfixed ignoring. The majority of the patients showed a left-side space and body ignoring and in 3 patients, with left-handedness signs, right-side ignoring has been observed. In all the patients ignoring development was associated with posthemorrhagic and postoperative impairment of the white matter (sensor conductor projections of sincipital and occipital lobes of periventricular white matter) or parietal and corpus callosum. In case of hemispheric local disturbances, ignoring developed in concomitant disorders (hemianopsia and hemihypesthesia) and coincided with them in modality. In case of corpus callosum damage, ignoring may develop without concomitant sensor disorders or may be on the other side (in case of simultaneous left hemisphere damage). The results obtained support the evidence for ignoring phenomenon independence.

Thalamic cavernous malformations.

BACKGROUND: Only few anecdotal reports and small series of thalamic cavernous malformations have been reported. It follows that the clinical behavior and management are poorly understood; in particular, experiences with the surgical treatment of these lesions are scarce. METHODS: The clinical course, treatment, and outcome of 12 patients (10 females and 2 males, mean age 36 years) with symptomatic cavernous malformations of the thalamus are reviewed. Eight patients (66%) presented with cerebral hemorrhage, one with progressive neurological deficit and three with hydrocephalus/increased intracranial pressure; associated venous anomalies were found in three cases. Treatment consisted of radical surgery in four cases with progressive neurological decline or recurrent disabling hemorrhage, radiosurgery (one case), evacuation of a chronic satellite hematoma (one case), ventriculoperitoneal shunt for hydrocephalus (one case) and observation (five cases). Operative treatment in four cases included transcallosal, trigonal, and occipital interhemispheric approaches. RESULTS: In the surgical group, one patient died, two improved after operation, and one remained the same. Of the patients not operated on radically, one had recurrent hemorrhage 4 months after radiosurgery, one remains stable 8 years after ventriculoperitoneal shunt, and one 3 years after aspiration of a satellite hematoma. Five other patients presenting with thalamic hemorrhage were treated conservatively; recurrent hemorrhage occurred in two cases at 1 month and at 2 years, leaving a mild residual deficit in both cases. Overall, rehemorrhage occurred in four cases (50%) at a mean interval of 18 months after the first bleeding; the annual hemorrhage rate was 6.1%. CONCLUSIONS: Thalamic malformations are more likely to be symptomatic from small hemorrhages compared with lesions in the cerebral hemispheres; progressive growth may also occur with third ventricle invasion or caudal extension to the midbrain. Their high-risk location deters heavy-handed management, but they should not be left long untreated. Both surgery and radiosurgery have been used in the management of thalamic cavernomas reported in the literature. Definite surgical indications include progressive neurological decline and recurrent hemorrhages of malformations abutting the ventricular surface or the posterior incisural space; the complex anatomy of the deep venous system and the association with unexpected venous anomalies complicates the removal of these lesions.