gms | German Medical Science

Objective: According to the results of the International Study of Unruptured Intracranial Aneurysms (ISUIA), the rate of rupture for aneurysms smaller than 7 mm in the anterior circulation (except posterior communicating artery, PCOM) in patients without a previous bleeding or familial history is 0.0%. The goal of the present retrospective register is to challenge a 0.0% rupture rate for these aneurysms.

Methods: A Central European Survey was performed in March 2011. 109 German, 8 Swiss and 11 Austrian Neurosurgical Departments participating in neurosurgical treatment of cerebral aneurysms were contacted by the register coordinators to report the incidence of aneurysm as such: 1) Incidental aneurysm of the anterior circulation (except PCOM) 2) Largest diameter lesser than 7 mm 3) Negative history for previous (subarachnoid hemorrhage) SAH 4) Negative familial history for SAH 5) No intention to treat 6) Subsequent subarachnoid hemorrhage from the previously diagnosed and untreated aneurysm.

Results: The overall response rate was 21.8%. The number of aneurysms meeting the inclusion criteria was 21, of which 13 were aneurysms of the anterior communicating artery and 8 of the middle cerebral artery. The documentation in all cases was provided by either CT or MRI and DSA studies of each individual as well as the patient history.

Conclusions: The retrospectively obtained data from the Central European Survey demonstrated that incidental and conservatively treated aneurysms of the anterior circulation with a diameter smaller than 7 mm do have a subsequent risk of rupture greater than 0.0%, despite the absence of risk factors. Therefore, additional and yet unknown variables influencing the threshold for aneurysm rupture remain to be investigated in a prospective, observational study.