Classification and Treatment of Aneurysms of the Vertebro-Basilar System

Abstract

SummaryIn continuation of my concept of classification of ICA-system aneurysms the classi fication of the vertebro-basilar-system aneurysms is presented. The classification takes into consideration the variability and anomalies of the vessels and the site and projec tion of the aneurysm. The aim of this classification is to improve the preoperative topographic diagnosis and the choice of approach. The operative management has been pioneered by one man : C. G. Drake, who described the technique in detail on hand of his enormous experience with 469 aneurysms of the vertebro-basilar system. The necessity of a "normal aneurysm neurosurgeon" treating such aneurysms requires certain modifications of indication, approach and dissection. Experience with microsurgical technique of management of aneurysms is absolutely necessary.Transoral, transclival access facilitates the direct isolation of the aneurysm at the difficult border level of the lower clivus and should become a routine similarly to the transsphenoidal operation. Electrothermic dissection of the aneurysm diminishes the risk of rupture during the isolation of the sack and facilitates the isolation of the neck.The statistics of Drake provide full data for the prognosis of these aneurysms. It is to note that in the recent time the results reported from different centers in which aneurysmal surgery is performed became more and more similar. The embolization of large bulbous or spheric and giant aneurysms by inflatable balloon-technique possibly may replace the risky direct or indirect operations.

Planning and surgical strategies for early management of vertebral artery and vertebrobasilar junction aneurysms

“…Reviewing the pertinent literature reveals a wide range of variations in site, size and morphology of aneurysms of the vertebral artery complex [16,17] which occur about one-tenth as frequently as those of the anterior circulation [13]. Correspondingly, experience with such aneurysms is more difficult to obtain than with aneurysms of the anterior circulation [23].…”

“…Among the various access routes for exposure of vertebral or vertebrobasilar junction aneurysms [8,16,26], the lateral suboccipital craniectomy is the most commonly used approach [1,5,10,12,14,17,23,25]. Depending on the location of the aneurysm, medullary retraction may sometimes be necessary during surgery [12] and may result in an injury to the lower cranial nerves by overstretching [1,7,23,27].…”

Radiometric Study on Posterior Inferior Cerebellar Aneurysms with Special Reference to Accessibility by the Lateral Suboccipital Approach

“…The posterior inferior cerebellar artery is a common site of aneurysms in the posterior fossa, second only to the terminal portion of the basilar artery. ', 4,9) The significance of anatomical variation of the vertebral artery and of the posterior inferior cerebellar artery has been pointed out by many authors.") Such variation seems to be the main cause of difficulties in direct surgical approach to these aneurysms with their proximity to the brain stem or lower cranial nerves in a very limited space of the posterior fossa.…”