R. Bibi

Are Anatomic Results Influenced by WEB Shape Modification? Analysis in a Prospective, Single-Center Series of 39 Patients with Aneurysms Treated with the WEB

BACKGROUND AND PURPOSE: Endovascular treatment with the flow-disrupter Woven EndoBridge aneurysm embolization system (WEB) is an innovative treatment for wide-neck bifurcation aneurysms. Prospective, multicenter studies have shown the high safety of this technique. Stability of aneurysm occlusion in long-term follow-up has been rarely studied. Moreover the “compression” phenomenon has been reported and seems to be associated with poor anatomic results. This prospective, single-center series analyzes the safety and efficacy of the WEB device in long-term follow-up in relation to WEB shape modification. MATERIALS AND METHODS: All patients with aneurysms treated with the WEB were prospectively included in a data base. Demographics, aneurysm characteristics, adverse events, and anatomic results were retrospectively analyzed. Anatomic results and modification of the WEB shape on the follow-up examinations were independently evaluated by a core laboratory. RESULTS: Thirty-nine patients were included. We observed few complications: intraoperative rupture in no patients (0.0%) and thromboembolic events in 3 patients (7.7%) with a permanent deficit in 1 (2.6%). At short-term, midterm, and long-term follow-up, adequate occlusion was obtained in 86.8%, 83.3%, and 87.5%, respectively. Retreatment rates were low (5.1%). At 6 months, WEB shape modification (compression/retraction) was observed in 31.6% of patients but was not associated with a lower rate of adequate occlusion. CONCLUSIONS: This prospective, single-center series with WEB devices used in 39 patients during 3.5 years confirms data from previous multicenter studies. Treatment can be accomplished with good safety and efficacy, with a high rate of adequate occlusion. Anatomic results were not worse in case of WEB shape modification.

The Role of Hemodynamics in Intracranial Bifurcation Arteries after Aneurysm Treatment with Flow-Diverter Stents

BACKGROUND AND PURPOSE: Treatment of intracranial bifurcation aneurysms with flow-diverter stents can lead to caliber changes of the distal vessels in a subacute phase. This study aims to evaluate whether local anatomy and flow disruption induced by flow-diverter stents are associated with vessel caliber changes in intracranial bifurcations. MATERIALS AND METHODS: Radiologic images and demographic data were acquired for 25 patients with bifurcation aneurysms treated with flow-diverter stents. Whisker plots and Mann-Whitney rank sum tests were used to evaluate if anatomic data and caliber changes could be linked. Symmetry/asymmetry were defined as diameter ratio 1 = symmetric and diameter ratio <1 = asymmetric. Computational fluid dynamics was performed on idealized and patient-specific anatomies to evaluate flow changes induced by flow-diverter stents in the jailed vessel. RESULTS: Statistical analysis identified a marked correspondence between asymmetric bifurcation and caliber change. Symmetry ratios were lower for cases showing narrowing or subacute occlusion (medium daughter vessel diameter ratio = 0.59) compared with cases with posttreatment caliber conservation (medium daughter vessel diameter ratio = 0.95). Computational fluid dynamics analysis in idealized and patient-specific anatomies showed that wall shear stress in the jailed vessel was more affected when flow-diverter stents were deployed in asymmetric bifurcations (diameter ratio <0.65) and less affected when deployed in symmetric anatomies (diameter ratio ∼1.00). CONCLUSIONS: Anatomic data analysis showed statistically significant correspondence between caliber changes and bifurcation asymmetry characterized by diameter ratio <0.7 (P < .001). Similarly, computational fluid dynamics results showed the highest impact on hemodynamics when flow-diverter stents are deployed in asymmetric bifurcations (diameter ratio <0.65) with noticeable changes on wall sheer stress fields. Further research and clinical validation are necessary to identify all elements involved in vessel caliber changes after flow-diverter stent procedures.

Quadruple Spontaneous Cervical Artery Dissection Following Aneurysm Embolization: A Rare Posttreatment Complication

SUMMARY: We present a unique case of multiple sCADs occurring after a ruptured intracranial aneurysm embolization. We discuss the impact of head extension during embolization as the prevailing factor in multiple artery dissections in this case and point out another cause of new-onset neurologic deficit in patients with aneurysmal SAH.

Kyste épidermoïde du quatrième ventricule

Une femme de 30 ans souffrait depuis un an de céphalées et de vertiges positionnels. L’examen neurologique montrait un élargissement du polygone de sustentation et un nystagmus vertical inférieur dont les caractéristiques en électronystagmographie évoquaient une origine centrale. Une IRM encéphalique a été réalisée à la recherche d’une atteinte du tronc cérébral ou du cervelet. Elle mettait en évidence une lésion nodulaire d’environ 4 cm d’axe cranio caudal sur 2 cm de largeur et d’épaisseur qui élargissait le quatrième ventricule (fig. 1) . Bien limitée, à contours irréguliers, elle était en hyposignal hétérogène sur la série pondérée en T1 et en isosignal au liquide cérébro-spinal (LCS) en T2 écho de spin non supprimé sur la séquence T2 FLAIR (fig. 2) . Sur la série pondérée en diffusion, la lésion était en hypersignal franc (fig. 3) avec une baisse du coefficient apparent de diffusion (ADC) (fig. 4) . L’injection de produit de contraste ne provoquait pas de rehaussement (fig. 5) . Devant ces constatations le diagnostic de kyste épidermoïde a été suspecté. Compte tenu du caractère symptomatique, une exérèse de la lésion a été décidée avec la patiente. En peropératoire, le kyste épidermoïde est apparu comme une tumeur blanche, nacrée et perlée, aux contours multi lobulés (fig. 6) , dont le corps se laissait facilement détacher par aspiration (fig. 7) . La paroi du kyste a été disséquée de l’artère cérébelleuse postéro inférieure (PICA) gauche (fig. 8) et de la toile choroïdienne du quatrième ventricule sur laquelle elle était implantée : l’exérèse était totale. L’étude microscopique des prélèvements peropératoires montrait un épithélium de type malpighien kératinisé, tapissant la face interne du kyste dont la lumière apparaissait emplie de squames anucléées (kératinocytes) (fig. 9) . La paroi du kyste était réduite à une mince lame de tissu fibreux dépourvu d’annexes pilo-sébacées (fig. 10) . Ces éléments confirmaient le diagnostic de kyste épidermoïde (1).

Échec de l’embolisation transartérielle par l’alcool absolu d’une fistule durale du sinus transverse

This is a case report of successful arterial embolization of a dural fistula using absolute alcohol. In this two-part embolization of a dural fistula of the left sagittal venous sinus, the use of n-BCA (n-butyl-cyanoacrylate) was followed by 1 ml of absolute alcohol four months later. The first procedure, using n-BCA via the external carotid, permitted exclusion of the arterial supply coming from the medial meningeal and occipital arteries. Persistence of the blood supply through the internal carotid prompted us to perform the second procedure, to occlude the tentorium marginalis artery, using 1 ml of 95% ethanol. This was followed by a cranial nerve (III) palsy that was reversible. The three-month follow-up was satisfactory, although arteriography after one year showed revascularization of the fistula, which was successfully treated by Onyx. Routinely used in the treatment of superficial vascular malformations, the use of absolute alcohol intracerebrally appears to be unreliable, with results that were only temporary.