Tag: Vascular malformations

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

J Neurosurg 132:122–131, 2020

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.

 

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Radiosurgery for Unruptured Brain Arteriovenous Malformations: An International Multicenter Retrospective Cohort Study

Neurosurgery 80:888–898, 2017

The role of intervention in the management of unruptured brain arteriovenous malformations (AVM) is controversial.

OBJECTIVE: To analyze in a multicenter, retrospective cohort study, the outcomes following radiosurgery for unruptured AVMs and determine predictive factors.

METHODS: We evaluated and pooled AVM radiosurgery data from 8 institutions participating in the International Gamma Knife Research Foundation. Patients with unruptured AVMs and ≥12 mo of follow-up were included in the study cohort. Favorable outcome was defined as AVM obliteration, no postradiosurgical hemorrhage, and no permanently symptomatic radiation-induced changes.

RESULTS: The unruptured AVM cohort comprised 938 patients with a median age of 35 yr. The median nidus volume was 2.4 cm3, 71% of AVMs were located in eloquent brain areas, and the Spetzler-Martin grade was III or higher in 57%. The median radiosurgical margin dose was 21 Gy and follow-up was 71 mo. AVM obliteration was achieved in 65%. The annual postradiosurgery hemorrhage rate was 1.4%. Symptomatic and permanent radiation-induced changes occurred in 9% and 3%, respectively. Favorable outcome was achieved in 61%. In the multivariate logistic regression analysis, smaller AVM maximum diameter (P = .001), the absence of AVM-associated arterial aneurysms (P = .001), and higher margin dose (P = .002) were found to be independent predictors of a favorable outcome. A margin dose ≥ 20 Gy yielded a significantly higher rate of favorable outcome (70% vs 36%; P < .001)

CONCLUSION: Radiosurgery affords an acceptable risk to benefit profile for patients harboring unruptured AVMs. These findings justify further prospective studies comparing radiosurgical intervention to conservative management for unruptured AVMs.

 

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Transvenous Approach to Intracranial Arteriovenous Malformations

Transvenous Approach to Intracranial Arteriovenous Malformations

Neurosurgery 77:644–652, 2015

A compartmental conceptualization of intracranial arteriovenous malformations (AVMs) allows recognition of feeding arteries, an intervening plexiform nidus, and draining veins. AVM therapy involves eliminating the nidus, which is the source of hemorrhage, without compromising normal arterial and venous drainage of the brain. Traditional methods of AVM therapy through microsurgery and endovascular embolization involve arterial devascularization, with preservation of AVM venous drainage, until the nidus is excluded.

The transvenous approach in treating vascular malformations was popularized by successful treatment models for dural arteriovenous fistulas. More recently, high-flow intracranial AVMs are being managed with transvenous endovascular approaches, although this novel technique has its challenges and perils.

We review the current literature on transvenous AVM therapy and highlight its role for AVM therapy in the present day.

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Effect of Prior Embolization on Cerebral Arteriovenous Malformation Radiosurgery Outcomes

AVM

Neurosurgery 77:406–417, 2015

Embolization before stereotactic radiosurgery (SRS) for cerebral arteriovenous malformations (AVM) has been shown to negatively affect obliteration rates, but its impact on the risks of radiosurgery-induced complications and latency period hemorrhage is poorly defined.

OBJECTIVE: To determine, in a case-control study, the effect of prior embolization on AVM SRS outcomes.

METHODS: We evaluated a database of AVM patients who underwent SRS. Propensity score analysis was used to match the case (embolized nidi) and control (nonembolized nidi) cohorts. AVM angioarchitectural complexity was defined as the sum of the number of major feeding arteries and draining veins to the nidus. Multivariate Cox proportional hazards regression analyses were performed on the overall study population to determine independent predictors of obliteration and radiation-induced changes.

RESULTS: The matching process yielded 242 patients in each cohort. The actuarial obliteration rates were significantly lower in the embolized (31%, 49% at 5, 10 years, respectively) compared with the nonembolized (48%, 64% at 5, 10 years, respectively) cohort (P = .003). In the multivariate analysis for obliteration, lower angioarchitectural complexity (P , .001) and radiologically evident radiation-induced changes (P = .016) were independent predictors, but embolization was not significant (P = .744). In the multivariate analysis for radiologic radiation-induced changes, lack of prior embolization (P = .009) and fewer draining veins (P = .011) were independent predictors.

CONCLUSION: The effect of prior embolization on AVM obliteration after SRS may be significantly confounded by nidus angioarchitectural complexity. Additionally, embolization could reduce the risk of radiation-induced changes. Thus, combined embolization and SRS may be warranted for appropriately selected nidi.

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Radiosurgery for Spetzler-Martin Grade III arteriovenous malformations

Multimodality management of Spetzler-Martin Grade III arteriovenous malformations

J Neurosurg 120:959–969, 2014

Intracranial arteriovenous malformations (AVMs) are most commonly classified based on their Spetzler- Martin grades. Due to the composition of the Spetzler-Martin grading scale, Grade III AVMs are the most heterogeneous, comprising 4 distinct lesion subtypes. The management of this class of AVMs and the optimal treatment approach when intervention is indicated remain controversial. The authors report their experience with radiosurgery for the treatment of Grade III AVMs in a large cohort of patients.

Methods. All patients with Spetzler-Martin Grade III AVMs treated with radiosurgery at the University of Virginia over the 20-year span from 1989 to 2009 were identified. Patients who had less than 2 years of radiological follow-up and did not have evidence of complete obliteration during that period were excluded from the study, leaving 398 cases for analysis. The median patient age at treatment was 31 years. The most common presenting symptoms were hemorrhage (59%), seizure (20%), and headache (10%). The median AVM volume was 2.8 cm3, and the median prescription dose was 20 Gy. The median radiological and clinical follow-up intervals were 54 and 68 months, respectively. Univariate and multivariate Cox proportional hazards and logistic regression analysis were used to identify factors associated with obliteration, postradiosurgery radiation-induced changes (RIC), and favorable outcome.

Results. Complete AVM obliteration was observed in 69% of Grade III AVM cases at a median time of 46 months after radiosurgery. The actuarial obliteration rates at 3 and 5 years were 38% and 60%, respectively. The obliteration rate was higher in ruptured AVMs than in unruptured ones (p < 0.001). Additionally, the obliteration rate for Grade III AVMs with small size (< 3 cm diameter), deep venous drainage, and location in eloquent cortex was higher than for the other subtypes (p < 0.001). Preradiosurgery AVM rupture (p = 0.016), no preradiosurgery embolization (p = 0.003), increased prescription dose (p < 0.001), fewer isocenters (p = 0.006), and a single draining vein (p = 0.018) were independent predictors of obliteration. The annual risk of postradiosurgery hemorrhage during the latency period was 1.7%. Two patients (0.5%) died of hemorrhage during the radiosurgical latency period. The rates of symptomatic and permanent RIC were 12% and 4%, respectively. Absence of preradiosurgery AVM rupture (p < 0.001) and presence of a single draining vein (p < 0.001) were independent predictors of RIC. Favorable outcome was observed in 63% of patients. Independent predictors of favorable outcome were no preradiosurgery hemorrhage (p = 0.014), increased prescription dose (p < 0.001), fewer isocenters (p = 0.014), deep location (p = 0.014), single draining vein (p = 0.001), and lower Virginia radiosurgery AVM scale score (p = 0.016).

Conclusions. Radiosurgery for Spetzler-Martin Grade III AVMs yields relatively high rates of obliteration with a low rate of adverse procedural events. Small and ruptured lesions are more likely to become obliterated after radiosurgery than large and unruptured ones.

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De Novo Formation of a Cavernoma in a Thrombosed Developmental Venous Anomaly

Magnetic Resonance Evolution of De Novo Formation of a Cavernoma in a Thrombosed Developmental Venous Anomaly

Neurosurgery 73:E739–E745, 2013

Mechanisms that lead to de novo formations of nonfamilial-type cavernomas are not well understood. One of the interesting hypotheses is the causative relationship between developmental venous anomaly (DVA) and cavernoma formation. We report a unique case in which serial imaging demonstrated the evolution of de novo formation of a cavernoma in association with a thrombosed DVA. A detailed review of the causal hypothesis between a DVA and cavernoma is also provided.

CLINICAL PRESENTATION: We report a 37-year-old female patient in whom a cavernoma-like lesion arose 1 year after the progressive thrombosis of a medullary (or caput medusa) vein of a DVA. The presence of an acute angulation in the draining vein may have prompted an intrinsic outflow restriction. Possible worsening of venous disequilibrium led to subsequent thrombus progression, venous congestion, and occlusion of the vein with venous dilation and signs of stasis on follow-up magnetic resonance imaging. Finally, this developed into a lobulated lesion with salt-and-pepper appearance at the converging region of medullary tributaries, which typified the classic features of a cavernoma.

CONCLUSION: Compared with other published cases of de novo cavernoma formation in relation to a DVA, our case, for the first time, allows us to witness the temporal evolution from a thrombosed DVA to the birth of a cavernoma around it. This supports the hypothesis that the cavernoma can be an acquired disease that arises from a DVA.

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Anterior subtemporal approach for posterolateral brainstem cavernomas

Acta Neurochir (2012) 154:2009–2016

The neuronavigation-assisted anterior subtemporal approach is proposed in this article as an alternative to surgery of posterolateral brainstem cavernomas. Brainstem cavernomas represent a neurosurgical challenge because of the high morbidity and mortality rate related to their surgical removal. Several nerve nuclei, ascending and descending fibers make this region at high risk of serious postoperative deficits.

Methods Between 1998 and 2010, 24 patients underwent surgical removal of brainstem cavernomas in our institution. Ten of these patients presented a cavernous malformation in the posterolateral region of the brainstem and underwent surgical removal by means of a neuronavigation-assisted anterior subtemporal approach.

Results Lesion removal was complete for all patients. There were no cases of surgery-related death. Neurological status improved or remained unchanged after surgery in all cases. All patients presented good outcomes at 12 to 154 months’ follow-up (mean 70 months; GOS05 in 8/10 patients, 4 in 2/10 patients; mRS00–1 in all patients). Only one patient presented transient confusion, aphasia and seizures related to temporal lobe swelling, which resolved completely within a few days. One patient developed cranial nerve III palsy and left hemiparesis with gradual recovery.

Conclusions This approach represents a valid alternative to the “more classical” approaches for the surgery of posterolateral cavernomas of the pontomesenchephalic junction reaching the tentorial incisura, reducing the risk of damaging the vein of Labbé, temporal lobe swelling, cerebellar swelling, ophtalmoparesis, fourth ventricle cranial nerve nuclei lesions. Skeletonization of sigmoidal sinus provides with good outcomes, low morbidity and mortality.

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