| Unruptured aneurysm |
| Prognosis of aneurysm |
 | Autopsy studies: at least 1% of the adult population
have unruptured intracranial aneurysms |
| .01 and .02% of the population suffers an aneurysmal
SAH every year |
| About 50% of patients admitted to neurosurgical centers with the diagnosis of aneurysmal SAH have a good outcome. |
| A brief review of Subarachnoid hemorrhage |
|
| Aneurysms < 5 mm |
| Usually asymptomatic |
| Very low risk of rupture |
| Young patients with aneurysms less than 6 mm who have suffered SAH from another aneurysm might be at a higher risk for rupture than a patient with a truly incidental aneurysm |
|
| Aneurysms 5 - 10 mm |
| Wiebers et al: suggested that aneurysms < 10 mm
have essentially no risk for future rupture if they are found in the unruptured state |
| Clinical reports with ruptured aneurysms where the average size of a recently ruptured aneurysm is about 7 mm. Weibers' interpretation of this
discrepancy is that the size of the filling compartment of the aneurysm decreases after rupture. |
| Patients with multiple aneurysms where one aneurysm has caused SAH. In this setting, rupture of a previously intact aneurysm is seen in about 2 to 4% of cases each year |
|
| Complication rates of
surgery for all patients |
| Closely correlate with the size of the aneurysm
 | < 1 cm: In properly selected patients,
about 1% major morbidity. |
| 1 - 2.5 cm: about 5% risk of major morbidity. |
| > 2.5 cm: about 20% risk of significant surgical morbidity or poor outcome |
| Giant basilar aneurysms: the poor outcome rate was 50%. |
|
| Location was not related to the incidence of complications except in giant aneurysms. |
| Age does correlate with mortality. |
|
| Further reading & references |
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