A Clinico-experimental Study on the Wrapping Material for Cerebral Aneurysm

In this paper, two interesting cases are introduced, one a multiple cerebral aneurysm with an infundibular dilatation of the left posterior communicating artery and a small bleb of the left anterior cerebral artery, both of which grew to large aneurysms in 10 years; the other an aneurysm of the middle cerebral artery, which recurred 6 years after treatment by neck clipping combined with muscle wrapping. These cases have motivated to conduct a histological experimental study, using 64 intracranial arteries of mongrel dogs, to evaluate the various materials so far used for the wrapping of cerebral aneurysms. The findings obtained were: 1) Muscle, fascia, and dura began to show necrotic and absorbable changes within 1 to 2 months after the operation, suggesting their unreliability as free pieces. 2) Lyodura® adhered poorly to vascular walls and showed detectable gaps against vessels. In addition, it showed necrosis and absorption in the bent site. 3) When Aron alpha A® alone was used for coating, its adhesion was unexpectedly poor; it easily peeled off from the vascular wall as a result of mutual interaction with vascular beating. It further became fragile and easily degradable with the passage of time. 4) Bemsheet® was superior in its adhesion to vascular walls, since it contributed greatly to the construction of a reinforced wall by proliferating collagen fibers in the space of the stereo-reticular structured cotton fiber. When Bemsheet® was fixed with Aron alpha A®, the latter permeated into the space of the reticular structured cotton fiber to form a sufficiently firmly reinforced wall immediately after treatment. The cotton fiber itself remained unchanged and gave almost no inflammatory reaction even after 12 months.