Lateral ventricular arteriovenous malformations: natural history and surgical indications

Location-based clinical and angiographic profile of brain arteriovenous malformations - a single-center observational study

BACKGROUND

The location of brain arteriovenous malformations (bAVM) is one of the most relevant prognostic factors included in surgical, endovascular and radiosurgical scores. However, their characteristics according to location are seldom described. The goal of this study was to describe the clinical and angiographic characteristics of bAVM classified according to their location.

METHODS

This retrospective observational study included patients diagnosed with bAVM and attending a national referral hospital during the period 2010-2020. Data regarding clinical and angiographic variables were extracted, including characteristics on nidus, arterial afferents, venous drainage and associated aneurysms. BAVM were classified in 8 groups according to their location: frontal, temporal, parieto-occipital, periventricular, deep, cerebellar, brainstem and mixed. Data distribution for each group was determined and between-group differences were assessed.

RESULTS

A total of 269 bAVM (in 258 patients) were included. The most frequent location was parieto-occipital; and the least frequent, brainstem. Statistically significant differences were observed between groups for most studied variables, including: clinical presentation, functional status at admission; nidus size and density, classification according to the Spetzler-Martin, Buffalo and modified Pollock-Flickinger scales; number, diameter, origin and type of afferents; number, diameter, type and direction of venous drainage, retrograde venous flow; and presence and size of flow-related aneurysms.

CONCLUSION

The clinical and angiographic differences observed between brain AVM groups allow the formulation of profiles according to their location.

Successful embolization of ventricular arteriovenous malformation supplied by the choroidal artery: A case report and literature review

BACKGROUND

Ventricular arteriovenous malformations (AVMs) are localized in the ventricles and are mainly fed by the anterior choroidal artery (AChoA) and posterior choroidal artery (PChoA). Surgical resection of ventricular AVMs is difficult as the lesions are localized deep in the brain. Therefore, endovascular treatment is expected to treat ventricular AVMs. However, embolization from the AChoA and PChoA carries the risk of ischemic complications. Even though there are some major reports on embolization strategies from the choroidal arteries, embolization of these arteries remains technically challenging. In this article, we report two successful cases of ventricular AVM embolization using AChoA and PChoA.

CASE DESCRIPTION

Case 1: A 34-year-old male presented with intraventricular hemorrhage (IVH). Subsequently, ventricular AVM embolization in the anterior horn was performed using n-butyl-2-cyanoacrylate (NBCA) through the AChoA and medial PChoA, and complete obliteration was observed without neurological deterioration. Case 2: A 71-year-old female presented with IVH. Subsequently, ventricular AVM embolization in the lateral ventricle was performed through the AChoA and lateral PChoA with Onyx and NBCA, and partial obliteration was observed without complications. Furthermore, Gamma Knife surgery for residual lesions resulted in complete obliteration.

CONCLUSION

Embolization through the choroidal arteries for ventricular AVMs is an effective curative or adjunctive treatment.

Gamma Knife surgery for arteriovenous malformations within or adjacent to the ventricles

Object

The outcomes of stereotactic radiosurgery for arteriovenous malformations (AVMs) within or adjacent to the ventricular system are largely unknown. This study assessed the long-term outcomes and hemorrhage risks for patients with AVMs within this region who underwent Gamma Knife surgery (GKS) at the University of Pittsburgh.

Methods

The authors retrospectively identified 188 patients with ventricular-region AVMs who underwent a single-stage GKS procedure during a 22-year interval. The median patient age was 32 years (range 3–80 years), the median target volume was 4.6 cm3 (range 0.1–22 cm3), and the median marginal dose was 20 Gy (range 13–27 Gy).

Results

Arteriovenous malformation obliteration was confirmed by MRI or angiography in 89 patients during a median follow-up of 65 months (range 2–265 months). The actuarial rates of total obliteration were 32% at 3 years, 55% at 4 years, 60% at 5 years, and 64% at 10 years. Higher rates of AVM obliteration were obtained in the 26 patients with intraventricular AVMs. Twenty-five patients (13%) sustained a hemorrhage during the initial latency interval after GKS, indicating an annual hemorrhage rate of 3.4% prior to AVM obliteration. No patient experienced a hemorrhage after AVM obliteration was confirmed by imaging. Permanent neurological deficits due to adverse radiation effects developed in 7 patients (4%).

Conclusions

Although patients in this study demonstrated an elevated hemorrhage risk that remained until complete obliteration, GKS still proved to be a generally safe and effective treatment for patients with these high-risk intraventricular and periventriclar AVMs.

Arteriovenous malformations

Arteriovenous malformations of the brain are congenital vascular lesions that affect 0.01-0.50% of the population, and are generally present in patients aged 20-40 years. The usual clinical presentations are haemorrhage, seizures, progressive neurological deficit, or headache. Results of natural history studies have shown a yearly haemorrhage rate of 1-4%. Frequency of rebleeding has increased over the years, and several factors that increase risk of haemorrhage have been identified. Although substantial, the morbidity associated with haemorrhages could be less than previously thought. Over the past decade, great advances have been made in application of endovascular embolisation techniques, stereotactic radiosurgery, and microsurgery, allowing effective multidisciplinary treatment of arteriovenous malformations, including those previously deemed to be untreatable. Increasing attention has been paid to management of flow-related aneurysms associated with these malformations. Finally, many reports of recurrent arteriovenous malformations have coincided with new theories regarding the embryogenesis of these disorders and laboratory work suggesting their proliferative potential.

Surgical management of arteriovenous malformations in the region of the ventricular trigone

The results in the surgical management of 26 patients with arteriovenous malformations intimately related to the trigone of the lateral ventricle are presented. Three operative approaches were used in the series, including a transtemporal route through the inferior or middle temporal gyrus (15 patients), an interhemispheric approach (8 patients), and a transcortical parieto-occipital approach (3 patients). The surgical approach was chosen on the basis of the relationship of the arteriovenous malformation to the trigone, the presence and location of associated hematoma, and preoperative neurological deficits. This report emphasizes the use of surgical adjuncts that are instrumental in the management of these challenging lesions, including magnetic resonance imaging for precise localization and operative planning, preoperative embolization to obliterate deep arterial supply, and intraoperative ultrasound and angiography to aid in localization and to document complete excision of the arteriovenous malformation before closure. The results of the management of these 26 patients are as follows: 21 had no or minor neurological deficits and were able to resume premorbid activities; 2 had a fair result, being independent but unable to resume their premorbid occupation; 2 had a poor result and were dependent as the result of an incapacitating neurological deficit; and 1 died.

Intra- and paraventricular arteriovenous malformations: symptomatology, neuroradiological diagnosis, surgical approach and postoperative results

A series of 8 patients with para- and intraventricular arteriovenous malformations (AVM) is presented. Confirmed by histopathological examination or based upon their history all of them sustained recurrent intraventricular or intracerebral haemorrhages. Our results strongly recommend a surgical removal of these AVMs as a feasible and mandatory form of treatment. Conservative methods, e.g., embolisation or gamma beam irradiation leave the patient susceptible to rebleeding which often results in devastating neurological deficits. Total removal of the AVM with minimal surgical trauma was achieved in 7 patients under controlled hypotension and was facilitated by stereotactic guidance in two patients. Post surgical re-bleeding was not observed in any of our patients even though in one case only a subtotal resection of the angiomatous malformation was achieved. Based on our experience, we advocate an inspection of the lateral ventricle in order to avoid leaving any intraventricular portion of the vascular malformation behind. MRI investigation is recommended because the multiplanar images clarify the topographic-anatomic location and its relation to important surgical landmarks.