Tag: Hemodynamic stress

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Clinical presentation and treatment of distal anterior inferior cerebellar artery aneurysms

Neurosurg Rev (2012) 35:497–504

Aneurysms located at the distal portion of the anterior inferior cerebellar artery (AICA) are rare, and their clinical features are not fully understood. We report the clinical features and management of nine distal AICA aneurysms in nine patients treated during the past decade at Kagoshima University Hospital and affiliated hospitals.

Our series includes seven women and two men. Of their nine aneurysms, eight were ruptured and one was unruptured; six were saccular and three were dissecting aneurysms. The most prevalent location was the meatal loop (n=5) followed by the postmeatal (n=3) and premeatal segment (n=1) of the AICA, suggesting hemodynamic stress as an etiology of these distal AICA aneurysms. Of the nine patients, five presented with angiographic features suggestive of increased hemodynamic stress to the AICA and the common trunk of the posterior inferior cerebellar artery, with vertebral artery stenosis, marked laterality, and a primitive hypoglossal artery.

We addressed eight aneurysms (eight patients) surgically; one aneurysm in one patient disappeared in the course of 3 months without surgical treatment. Of the eight surgically treated aneurysms, seven were ruptured and one was unruptured, five were clipped via lateral suboccipital craniotomy, two were trapped via lateral suboccipital craniotomy, and one was embolized. Good outcomes were obtained in six of the eight patients who underwent operation (75 %).

We consider increased hemodynamic stress attributable to anatomic variations in the AICA and related posterior circulation to be the predominant contributor to the development of distal AICA aneurysms. Direct clipping and trapping yielded favorable outcomes in our series.

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Clinical presentation and treatment of distal posterior inferior cerebellar artery aneurysms

Neurosurg Rev. DOI 10.1007/s10143-010-0296-z

Aneurysms located at the distal portion of the posterior inferior cerebellar artery (PICA) are rare, and their clinical features are not fully understood. We report the clinical features and management of 30 distal PICA aneurysms in 28 patients treated during the past decade at Kagoshima University Hospital and affiliated hospitals.

Our series includes 20 women and eight men. Of their 30 aneurysms, 24 were ruptured, and six were unruptured; there were 27 saccular and two fusiform aneurysms; one was dissecting. Their location was at the anterior-medullary (n=4), lateral-medullary (n=9), tonsillomedullary (n=7), telovelotonsillar (n=6), and cortical (n =4) segment of the PICA. In 18 patients, angiographic features suggested hemodynamic stress including an absent contralateral PICA or ipsilateral anterior inferior cerebellar artery, termination of the vertebral artery (VA) at the PICA, and hyperplasia or occlusion of the contralateral VA.

As three patients died before surgery, 27 aneurysms in 25 patients were surgically treated. Of these, 6 were unruptured aneurysms; 20 were clipped via midline or lateral suboccipital craniotomy, and 5 were embolized with Guglielmi coils; in one, the PICA flow was reconstructed by OA-PICA anastomosis, and in the other one, the PICA was resected.

Of the 25 surgically treated patients, 22 (88%) had good outcomes. The predominant contributor to the development of distal PICA aneurysms is thought to be increased hemodynamic stress attributable to anomalies in the PICA and related posterior circulation. Both direct clipping and coil embolization yielded favorable outcomes in our series. However, considering the difficulties that may be encountered at direct clipping in the acute stage and the availability of advanced techniques and instrumentation, aneurysmal coiling is now the first option to address these aneurysms.

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