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.
Mizoi
K
K
Department of Neurosurgery, Tohoku University School of Medicine, Sendai, Japan.
Yoshimoto
T
T
Nagamine
Y
Y
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