Subdural hematomas (SDH) from ruptured aneurysm (RA) are much less common than intracerebral (ICH) hematomas or subarachnoid (SAH) or intraventricular hemorrhage (IVH). With computerized tomography, preoperative diagnosis is now made more often. The authors have collected 18 such cases from a review of 897 cases of RA admitted to eleven medical centers in 1980 and 1981. Nine (50%) of these patients died prior to discharge from hospital. Four (22%) had surgery and died postoperatively and 9 (50%) were operated upon and survived. Thirteen (72%) of the patients showed anisocoria, decreased consciousness and unilateral weakness prior to surgery. Eight (89%) of the fatalities had shown preoperative herniation as opposed to only 5 (56%) of the survivors. The overall incidence of delayed ischemia due to vasospasm was 11% (2 cases). Those who died had greater midline shift and larger SDH on the admission CT scan. Sixteen (89%) of these patients were female. Thirteen (72%) had ruptured aneurysms on the internal carotid artery. All of these hematomas were unilateral and uniformly hyperdense, and the convexity hematomas were crescentic in shape. Seventeen (94%) had evidence of blood in locations other than the subdural space. If the patient is potentially salvageable and has a midline shift, the SDH should probably be evacuated immediately and the aneurysm clipped at the same operation since the development of a tentorial herniation has such an adverse effect on outcome. RESUME: A la suite de la rupture d'un an6vrysme, I'hdmatome sous-dural est beaucoup moins frequent que 1'hematome intracerebral ou l'h6morragie sous-arachnoidienne. La tomodensitom&rie en permet plus frdquemment le diagnostic pr6-op£ratoire. Le auteurs ont collige" dix-huit de ces cas apres revision de 897 cas d'an£vrysmes ruptures admis dans onze centres m6dicaux en 1980 et 1981. Neuf (50%) de ces patients dec6derent avant leur conge" de I'hdpital. Quatre (22%) avaient ixi trails chirurgicalement et moururent dans la periode post-ope>atoire. Neuf (50%) furent operas et survdcurent. Treize (72%) des patients pr6senterent une anisocorie, une diminution de l'6tat de conscience et une faibiesse unilat6rale avant la chirurgie. Chez huit (89%) de ces patients d£c6des, on avait trouv6 une engagement cerebral, alors que ceci se pr6senta seulement dans cinq (56%) des survivants. L'incidence globale de l'ischemie tardive secondaire au vasospasme fut de 11% (2 cas). Ceux qui moururent avaient un plus grand defacement de la ligne mddiane et un HSD plus volumineux sur la tomodensitom6trie a l'admission. Seize (89%) de ces patients etaient des femmes. Treize (72%) £taient porteurs d'un an£vrysme rupture" de la carotide interne. Tous ces h^matomes Etaient unilateYaux et d'une hyperdensite homogene et les h^matomes de la convexite avaient une forme de croissant. Chex dix-sept (94%), on d£cela la presence de sang dans d'autres sites que l'espace sous-dural. Si le patient est potentiellement r£cuperable et a un defacement de la ligne mediane, l'HSD devrait probab...