1999 Fiscal Year Final Research Report Summary
MECHANISMS OF CEREBRAL ANEURYSM RUPTURE
| Project/Area Number |
09470303
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Cerebral neurosurgery
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| Research Institution | KINKI UNIVERSITY |
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Principal Investigator |
TANEDA Mamoru Kinki University, Dept Neurosurgery, Professor, 医学部, 教授 (10236713)
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| Co-Investigator(Kenkyū-buntansha) |
ASAI Toshiharu Kinki University, Dept Neurosurgery, Associate Professor, 医学部, 講師 (20248008)
KATAOKA Kazuo Kinki University, Dept Neurosurgery, Associate Professor, 医学部, 助教授 (10221178)
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| Project Period (FY) |
1997 – 1999
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| Keywords | Cerebral aneurysm / Subarachnoid hemorrhage |
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| Research Abstract |
A recent article published in the New England Journal of Medicine(N Engl J Med 339 : 1725, 1998) discussed the benign natural history of small unruptured cerebral aneurysms in patients with no history of subarachnoid hemorrhage (SAH) from another aneurysm. The report came from the International Study of Unruptured Intracranial Aneurysms Investigators, a group representing multiple centers. That article engendered a flurry of criticisms. As neurosurgeons who treat patients with aneurysmal SAH often find that most ruptured aneurysms are less than 10 mm in diameter, they cannot easily accept the concept that small incidental aneurysms are benign lesions. Our study attempts to address the difference between the experience of practicing neurosurgeons and the claims made by the International Study of Unruptured Intracranial Aneurysms Investigators. The incidence of unruptured aneurysms is 6-7% in the adult population. It is widely believed that unruptured aneurysms are the latent but sole cause of aneurysmal SAH.
Histologic study of aneurysms and epidemiologic analysis of SAH reveal that ruptured and unruptured aneurysms are of a different nature. Our histologic study suggests that approximately 50% of small aneurysms(<10 mm in diameter) result in SAH just after acute aneurysm development or upon rapid expansion of very small aneurysms. It may be difficult to diagnose the vascular lesions that may progress to ruptured aneurysms. Therefore, aneurysmal SAH may occur in people who are though to be free of unruptured aneurysms. If the acutely stretched fragile wall fails to rupture, a repair process may work and upon its completion the risk of bleeding from the unruptured aneurysms may be low.
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