Italian cooperative study on giant intracranial aneurysms: 1. Study design and clinical data.

10 Italian centres joined together for a retrospective Cooperative Study aimed at evaluating clinical and radiological data, various modalities of treatment and clinical outcome in patients with giant intracranial aneurysms, observed from 1976 to 1986. Various clinical data were collected through a questionnaire and evaluated through computer analysis. Two size categories were considered: 2-2.5 cm in diameter (A 1 group) and over 2.5 cm (A 2 group). A total of 240 cases were evaluated: 110 in A 1 group and 130 in A 2 group. As regards clinical history, intracranial (mainly subarachnoid) haemorrhage was observed in 70% of A 1 patients and in 45% of A 2 patients (p less than 0.001) and was more severe (Hunt's grades III-V) in A 2 patients. Symptoms of an expanding mass lesion were observed in 15% of A 1 patients and in 39% of A 2 patients (p less than 0.001). Sudden deficits of cranial nerves were observed in 11% of A 1 and 12% of A 2 patients. Ischaemic episodes were rare. On admission, Glasgow Coma Score (GCS) was 15 in 62% of cases. Regardless of treatment employed, patients in A 1 group presented a slightly better (N.S.) outcome than patients with larger aneurysms (A 2 group). The presence of intracranial haemorrhage in the clinical history increased significantly the mortality rate (p less than 0.001); symptoms of an expanding mass lesion were associated with a significant increase in the disability rate (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)