Types of unruptured cerebral aneurysms reviewed from operation video-recordings.
To estimate the proportion of unruptured cerebral aneurysms with thin-walled sac, we have analyzed the operative findings of 78 incidental cerebral aneurysms found in 51 consecutive surgical cases by reviewing of intra-operative videotape recordings. Among 78 unruptured aneurysms, 23 (30%) were evaluated as thick-walled aneurysms (Type A), 39 (50%) with partially thin-walled sac (Type B) and 16 (20%) with entirely thin wall sacs (Type C). The mean size of Type A aneurysms was 10.4 mm (ranging from 3 to 22 mm), in Type B it was 9.8 mm (ranging 4 to 25 mm) and in Type C it was 4.4 mm (between 2-12 mm). Approximately two-thirds of Type C aneurysms were 4 mm in size or smaller, and Type C aneurysms were significantly smaller than Type A aneurysms. In summary, this preliminary study has provided two original data. 1) About 70% of incidental unruptured aneurysms have a partially or entirely thin-walled sac. 2) Many of the small aneurysms have an entirely thin sac. Assuming that thin-walled aneurysms are at a high risk of subsequent rupture, the surgical intervention for incidental unruptured aneurysms may be recommended irrespective of their size if the surgical risk is considered low.
Department of Neurosurgery, Tohoku University School of Medicine, Sendai, Japan.
K
K
Mizoi
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T
Yoshimoto
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Y
Nagamine
D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D006973:Hypertension / Q000150:complications; D002532:Intracranial Aneurysm / Q000150:complications / Q000473:pathology* / Q000601:surgery*; D007432:Intraoperative Period; D008297:Male; D008875:Middle Aged; D012422:Rupture, Spontaneous; D014743:Videotape Recording