- National Brain Aneurysm Center, St. Joseph's Hospital, St. Paul, MN, USA
Eric S. Nussbaum
National Brain Aneurysm Center, St. Joseph's Hospital, St. Paul, MN, USA
DOI:10.4103/2152-7806.81731Copyright: © 2011 Nussbaum ES. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
How to cite this article: Nussbaum ES, Defillo A, Zelensky A, Stoller R, Nussbaum L. Dissecting peripheral superior cerebellar artery aneurysms: Report of two cases and review of the literature. Surg Neurol Int 28-May-2011;2:69
How to cite this URL: Nussbaum ES, Defillo A, Zelensky A, Stoller R, Nussbaum L. Dissecting peripheral superior cerebellar artery aneurysms: Report of two cases and review of the literature. Surg Neurol Int 28-May-2011;2:69. Available from: http://sni.wpengine.com/surgicalint_articles/dissecting-peripheral-superior-cerebellar-artery-aneurysms-report-of-two-cases-and-review-of-the-literature/
Background:Only a limited number of dissecting aneurysms of the peripheral cerebellar arteries have been previously described, and very few of these cases involve the superior cerebellar artery (SCA). Due to the rarity of these lesions, there is little consensus regarding prognosis and management. We describe our experience with two cases of complex peripheral SCA dissecting aneurysms and review the existing literature on this fascinating entity.
Case Description:Two patients, both with SCA dissecting aneurysms not amenable to endovascular treatment underwent microsurgical clipping, one with the associated removal of a tentorial meningioma. In each procedure a combined subtemporal, presigmoidal approach was performed. Surgical clips were utilized to reconstruct the aneurysms, and both patients were discharged without complication. Surgical management of complex distal SCA fusiform aneurysm is challenging and options include wrap/clip reconstruction, proximal occlusion, trapping, and distal outflow occlusion. When possible, preservation of the parent artery is preferred to mitigate the risk of brainstem infarction. If proximal occlusion or trapping are employed, we have advocated for the use of combined distal revascularization techniques to prevent permanent ischemic damage of the brainstem and cerebellar hemisphere.
Conclusions:Peripherally dissecting aneurysm of the SCA is an uncommon entity. Management of these lesions is best handled by an experienced neuro-endovascular team combined with a neurovascular surgeon skilled in skull base approaches.
Keywords: Dissecting aneurysm, distal outflow occlusion, presigmoidal approach, subtemporal approach, superior cerebellar artery
Only a limited number of dissecting aneurysms of the peripheral cerebellar arteries have been previously described, and very few of these cases involve the superior cerebellar artery (SCA). Due to the rarity of these lesions, there is little consensus regarding prognosis and management. We describe our experience with two cases of complex peripheral SCA dissecting aneurysms and review the existing literature on this fascinating entity.
A 60-year-old woman who developed intermittent diplopia underwent MRI scan revealing a tentorial meningioma as well as aneurysms of the posterior communication artery, right vertebral artery, and peripheral superior cerebellar artery. The tentorial meningioma tumor was located in the posterior aspect of the cerebellopontine angle and causing compression of the brainstem along the course of the 4th cranial nerve, and the complex, partially thrombosed dissecting aneurysm of the SCA was situated just proximal to the entry of the 4th nerve into the free edge of the tentorium. Angiography revealed a partially thrombosed wide-necked aneurysm not amenable to endovascular intervention. Microsurgical clipping and simultaneous tumor removal were recommended.
A combined subtemporal, presigmoidal approach was performed. A wide bone removal of the middle cranial fossa was necessary to reach the tentorial incisura allowing exposure of the tumor. Due to the associated brainstem compression from the tumor, the meningioma was debulked first, and then the aneurysm was addressed. Interestingly, on reaching the SCA there was obvious hemosiderin staining of the arachnoid surrounding the aneurysm dome, indicating a previous rupture. During microsurgical dissection, it was confirmed that this aneurysm was thick-walled and partially thrombosed [Figure
A 70-year-old woman with hypertension, hyperlipidemia, and a history of smoking presented with a peripheral fusiform SCA aneurysm found incidentally during a routine MRI investigation due to “black out” symptoms. The aneurysm was located 2 cm from the SCA origin, and measured 7 mm in maximal diameter [Figure
Aneurysms of the vertebrobasilar system comprise fewer than 10% of all intracranial saccular aneurysms.[
Peripheral SCA aneurysms can be either true saccular lesions or dissecting aneurysms. Saccular aneurysms of the distal SCA have been described most commonly involving the cortical or hemispheric segment at the level of the superior vermian branches.[
When presenting with subarachnoid hemorrhage (SAH), the diagnosis of a dissecting aneurysm of the SCA can be difficult, requiring serial angiograms to identify progressive change in the affected vascular segment. Araki et al., described a case of a SCA dissecting aneurysm only revealing a slightly enlarged lesion at the anterior pontine segment on the admission angiogram. A second angiogram similarly failed to define the lesion. A third angiogram on 16th day of admission revealed a saccular aneurysm-like lesion arising at that region where the intraluminal pooling was noticed.[
Surgical options for the management of dissecting SCA aneurysms include wrap/clip reconstruction, proximal occlusion, trapping, and distal outflow occlusion.[
Surgical management of complex distal SCA aneurysms is challenging. These aneurysms are handled best at centers with neurovascular surgeons comfortable with complex revascularization options as well as a variety of skull base techniques including subtemporal transtentorial for aneurysms arising from the anterior and lateral pontomesencephalic segment, subtemporal or occipital transtentorial for aneurysms arising from the cerebellomesencephalic segment, and infratentorial supracerebellar for aneurysms arising from the distal or hemispheric branch of the SCA.[
Peripheral, dissecting aneurysm of the SCA is very uncommon. We describe two such cases that were treated successfully with direct surgical reconstruction. Our experience supports the potential for parent vessel preservation in this setting. When vascular occlusion is contemplated, revascularization of the distal arterial territory should be considered to decrease the risk of ischemic injury.
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