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Michel W. Bojanowski, Gunness V. R. Nitish, Gilles El Hage, Kim Lalonde, Chiraz Chaalala and Thomas Robert

Cavernous malformations in the midbrain can be accessed via several safe entry zones. The accepted rule of thumb is to enter at the point where the lesion is visible at the surface of the brainstem to pass through as little normal brain tissue as possible. However, in some cases, in order to avoid critical neural structures, this rule may not apply. A different safe entry zone can be chosen. Our video presents a case of a ruptured cavernous malformation in the midbrain reaching its anterior surface which was successfully resected via a posterolateral route using the supracerebellar infratentorial approach.

The video can be found here:

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Elsa Magro, Jean-Christophe Gentric, André Lima Batista, Marc Kotowski, Chiraz Chaalala, David Roberge, Alain Weill, Christian Stapf, Daniel Roy, Michel W. Bojanowski, Tim E. Darsaut, Ruby Klink and Jean Raymond


The management of brain arteriovenous malformations (bAVMs) remains controversial. The Treatment of Brain AVMs Study (TOBAS) was designed to manage patients with bAVMs within a clinical research framework. The objective of this study was to study trial feasibility, recruitment rates, patient allocation to the various management groups, and compliance with treatment allocation.


TOBAS combines two randomized care trials (RCTs) and a registry. Designed to be all-inclusive, the study offers randomized allocation of interventional versus conservative management to patients eligible for both options (first RCT), a second RCT testing the role of preembolization as an adjunct to surgery or radiotherapy, and a registry of patients managed using clinical judgment alone. The primary outcome of the first RCT is death from any cause or disabling stroke (modified Rankin Scale score > 2) at 10 years. A pilot phase was initiated at one center to test study feasibility, record the number and characteristics of patients enrolled in the RCTs, and estimate the frequency of crossovers.


All patients discussed at the multidisciplinary bAVM committee between June 2014 and June 2016 (n = 107) were recruited into the study; 46 in the randomized trials (23 in the first RCT with 21 unruptured bAVMs, 40 in the second RCT with 17 unruptured bAVMs, and 17 in both RCTs), and 61 patients in the registry. Three patients crossed over from surgery to observation (first RCT).


Clinical research was successfully integrated with normal practice using TOBAS. Recruitment rates in a single center are encouraging. Whether the trial will provide meaningful results depends on the recruitment of a sufficient number of participating centers.

Clinical trial registration no.: NCT02098252 (

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Tim E. Darsaut, Laurent Estrade, Sara Jamali, Michel W. Bojanowski, Miguel Chagnon and Jean Raymond


The management of unruptured intracranial aneurysms remains controversial. The goal of this study was to evaluate the clinical community agreement in decision making regarding unruptured intracranial aneurysms.


A portfolio of 41 cases of unruptured intracranial aneurysms with angiographic images, along with a short description of the patient presentation, was sent to 28 clinicians (16 radiologists and 12 surgeons) with varying years of experience in the management of unruptured intracranial aneurysms. Five senior clinicians responded twice at least 3 months apart. Nineteen cases (46%) were selected from patients recruited in the Canadian UnRuptured Endovascular versus Surgery trial, an ongoing randomized comparison of coil embolization and clip placement. For each case, the responder was to first choose between 3 treatment options (observation, surgical clip placement, or endovascular coil embolization) and then indicate their level of certainty on a quantitative 0–10 scale. Agreement in decision making was studied using κ statistics.


Decisions to coil were more frequent (n = 612, 53%) than decisions to clip (n = 289, 25%) or to observe (n = 259, 22%). Interjudge agreement was only fair (κ = 0.31 ± 0.02) for all cases and all judges, despite substantial intrajudge agreement (range 0.44–0.83 ± 0.10), with high mean individual certainty levels for each case (range 6.5–9.4 ± 2.0 on a scale of 0–10). Agreement was no better within specialties (surgeons or radiologists), within capability groups (those able to perform endovascular coiling alone, surgical clipping alone, or both), or with more experience. There was no correlation between certainty levels and years of experience. Agreement was lower when the cases were taken from the randomized trial (κ = 0.19 ± 0.2) compared with nontrial cases (κ = 0.35 ± 0.2).


Individuals do not agree regarding the management of unruptured intracranial aneurysms, even when they share a background in the same specialty, similar capabilities in aneurysm management, or years of practice. If community equipoise is a necessary precondition for trial participation, this study has found sufficient uncertainty and disagreement among clinicians to justify randomized trials.