Successful combined treatment of a giant aneurysm of the posterior inferior cerebellar artery manifesting by brain stem compression

Giant aneurysms of the vertebrobasilar basin manifesting as brain stem compression are a rare pathology with an incidence ranging from 3 to 13,5 %. Surgery of such aneurysms is often associated with unsatisfactory treatment results due to the high traumatic nature of direct surgery on aneurysms of this region, as well as the close proximity of vital brain structures. Surgical intervention is also hampered by the large volume of the aneurysm, possible presence of thrombus in the sac, frequent absence of the neck, location in the anatomically difficult region, and small volume of the posterior cranial fossa (PCF). The above factors make it difficult to clip the aneurysm and increase the risk of perioperative complications. Endovascular intervention is a method of choice in most cases allowing to switch an aneurysm off the blood flow, however in the presence of mass effect aneurysm occlusion does not always achieve a clinical effect due to the preservation of brain stem compression. The aim of this publication was to demonstrate the possibility of successful combined surgical treatment of a giant aneurysm located in the PCF and accompanied by brain stem compression.