Arteriovenous malformations of the posterior fossa: a systematic review

The influence of hemorrhage presentation on clinical outcomes of curative embolisation in 125 cerebellar arteriovenous malformations

BACKGROUND

This study investigated the influence of periprocedural hemorrhage and clinical outcomes with an endovascular therapeutic strategy for cerebellar arteriovenous malformations (cAVMs).

METHODS

From December 2006 to January 2018, 125 cAVMs were classified as types I-IV and received endovascular embolization via Onyx or Glubran 2. The risk factors of hemorrhage were analyzed using univariate and multivariate logistic analyses. A modified Rankin Scale (mRS) score was used to evaluate the neurological function before and 1 year after the operation. Results Of 125 patients, 63 had type I cAVMs, 2 type II cAVMs, 48 type III cAVMs, and 12 type IV cAVMs. A total of 88 (70.4%) patients had clinical manifestations of intracranial hemorrhage. Multivariate logistic regression analysis showed that age (OR, 2.276; 95% CI, 1.132 - 5.663), flow-related aneurysm (OR, 2.845; 95% CI, 1.265 - 6.248), lesion size (OR, 3.005; 95% CI, 1.119 - 5.936), and the number of feeding arteries (OR, 0.105; 95% CI, 0.081 - 0.312) were still the significant independent risk factors of intracranial hemorrhage. During a 1-year follow-up, 109 patients (87.2%) had good outcomes (mRS 0 - 2), 12 patients (9.6%) had poor outcomes (mRS 3 - 4), 4 patients (3.2%) died, and 3 patients had intracranial hemorrhage due to the incomplete embolization of cAVMs.

CONCLUSIONS

Endovascular embolization is a feasible treatment for cAVMs. Age, flow-related aneurysm, lesion size, and the number of feeding arteries are the significant risk factors of periprocedural hemorrhage. Moreover, the lesion characteristics must be given full consideration when using Onyx or Glubran 2 before cAVMs embolization.

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.

Characterization of Pediatric Infratentorial Arteriovenous Malformations: A Retrospective, Multicenter Cohort Study

BACKGROUND AND OBJECTIVES

Infratentorial arteriovenous malformations (AVMs) harbor different characteristics compared with supratentorial AVMs. This study aims to explore the unique characteristics of pediatric infratentorial AVMs and their response to single session stereotactic radiosurgery (SRS).

METHODS

The International Radiosurgery Research Foundation database of pediatric patients with AVM (age <18 years) who underwent SRS was retrospectively reviewed. Baseline demographics, AVM characteristics, outcomes, and complications post-SRS were compared between infratentorial and supratentorial pediatric AVMs. Unfavorable outcome was defined as the absence of AVM obliteration, post-SRS hemorrhage, or permanent radiation-induced changes at last follow-up.

RESULTS

A total of 535 pediatric AVMs managed with SRS with a median follow-up of 67 months (IQR 29.0-130.6) were included, with 69 being infratentorial and 466 supratentorial. The infratentorial group had a higher proportion of deep location (58.4% vs 30.3%, P = <.001), deep venous drainage (79.8% vs 61.8%, P = .004), and prior embolization (26.1% vs 15.7%, P = .032). There was a higher proportion of hemorrhagic presentation in the infratentorial group (79.7% vs 71.3%, P = .146). There was no statistically significant difference in the odds of an unfavorable outcome (odds ratio [OR] = 1.36 [0.82-2.28]), AVM obliteration (OR = 0.85 [0.5-1.43]), post-SRS hemorrhage (OR = 0.83 [0.31-2.18]), or radiologic radiation-induced changes (OR = 1.08 [0.63-1.84]) between both cohorts. No statistically significant difference on the rates of outcomes of interest and complications were found in the adjusted model.

CONCLUSION

Despite baseline differences between infratentorial and supratentorial pediatric AVMs, SRS outcomes, including AVM obliteration and post-SRS hemorrhage rates, were comparable amongst both groups. SRS appears to have a similar risk profile and therapeutic benefit to infratentorial pediatric AVMs as it does for those with a supratentorial location.

Imaging characteristics and endovascular treatment strategy for cerebellar arteriovenous malformations

Cerebellar arteriovenous malformations (CAVMs) have increased probabilities of rupture and bleeding compared with arteriovenous malformations (AVMs) in other locations of the brain. Endovascular treatment (EVT) for CAVMs is difficult; as the angioarchitecture of CAVMs is complex, EVT may be associated with complications, due to the involvement of crucial structures, such as the brainstem. The present study aimed to determine the efficacy of EVT for CAVMS. For this purpose, 33 cases of CAVMs treated with EVT from January, 2015 to January, 2020 were retrospectively analyzed. The 33 patients were aged 8 to 73 years (mean age, 40.4±17.8 years) and 21 were female (63%, 21/33). Rupture and bleeding occurred in 29 patients (87.9%, 29/33). Among the 33 CAVM cases, 15 (45.5%, 15/33) were fed by a single artery, and 18 (54.5%, 18/33) were fed by multiple arteries. In total, 27 patients (81.8%, 27/33) had superficial vein drainage alone. Among the 33 cases, 15 were complicated by 16 aneurysms, including 14 prenidal aneurysms and 2 intranidal aneurysms. Among the 33 cases, the nidus of the CAVM (87.9%, 29/33) was treated with Onyx^™ casting in 29 patients: 8 cases (27.6%, 8/29) had an embolization volume of <1/3 of the nidus, 11 cases had a volume of 1/3-2/3 of the nidus (37.9%, 11/29) and 10 cases had a volume >2/3 of the nidus (34.5%, 10/29). Among the EVT complications, there were 3 cases (9.1%, 3/33) of intraoperative and post-operative bleeding, which resulted in two deaths (on the 1st and 7th days). The length of hospital stay was 10.7±5.4 days. In total, 27 patients (81.7%, 27/33) had a Glasgow Outcome Scale (GOS) score of 5 at discharge. On the whole, the present study demonstrates that overall, EVT is a feasible treatment for CAVM and may be used to obtain acceptable therapeutic effects.

Multimodal treatment of a pediatric posterior fossa arteriovenous malformation employing endovascular and microsurgical techniques

Intracranial hemorrhage is the most common presentation of posterior fossa arteriovenous malformations (AVMs) and may have serious consequences. The authors present a case of a 7-year-old girl with headache, vomiting, dysmetria, and ataxia due to a ruptured cerebellar grade III AVM. After two sessions of embolization, the patient underwent total microsurgical resection through a suboccipital craniotomy. There were no additional postoperative deficits, and the patient improved progressively during 6 months of rehabilitation. These challenging lesions should be removed after rupture, especially in children with long-term cumulative risk of rebleeding. Multimodal treatment reduces the perioperative bleeding, allowing better outcomes for pediatric AVM.

The video can be found here: https://youtu.be/HQWnjD8ENZQ

COVID-19 Pandemic and Its Impact on Neurosurgery Practice in Malaysia: Academic Insights, Clinical Experience and Protocols from March till August 2020

The newly discovered coronavirus disease 2019 (COVID-19) is an infectious disease introduced to humans for the first time. Following the pandemic of COVID-19, there is a major shift of practices among surgical departments in response to an unprecedented surge in reducing the transmission of disease. With pooling and outsourcing of more health care workers to emergency rooms, public health care services and medical services, further in-hospital resources are prioritised to those in need. It is imperative to balance the requirements of caring for COVID-19 patients with imminent risk of delay to others who need care. As Malaysia now approaches the recovery phase following the pandemic, the crisis impacted significantly on neurosurgical services throughout the country. Various emergency measures taken at the height of the crisis may remain as the new normal in the provision of neurosurgical services and practices in Malaysia. The crisis has certainly put a strain on the effective delivery of services and as we approach the recovery era, what may have been a strain may prove to be a silver lining in neurosurgical services in Malaysia. The following details are various measures put in place as the new operational protocols for neurosurgical services in Malaysia.