Introduction:
Complex intracranial aneurysms (CIA) are heterogenous group of intracranial vascular malformations. Due to its giant size, difficult location, broad neck, branches arising from the aneurysm, wall structure, calcification, presence of intraluminal thrombus or previous treatments it requires more careful approach. The aim of this study was to evaluate endovascular treatment results of CIA in our Department.

Material and methods:
In order to differentiate CIA from all the aneurysms, treated endovascularly in years 2008-2014, authors proposed their own qualification criteria. Additionally, subgroup of patients with CIA with simultaneous subarachnoid haemorrhage (SAH) was divided. Clinical outcomes of patients were assessed with Glasgow Outcome Scale (GOS), while radiological outcomes were assessed with Montreal Scale. Aneurysm localization, incidence of aborted procedures, intraoperative complications were also evaluated.

Results:
Internal carotid artery was the most common localization in both CIA and non-complex (nCIA) groups. Incidence of aborted procedures was significantly higher in CIA group than in nCIA (25% vs. 7%; p < 0.01). CIA group had worse Montreal scores then nCIA group (1.90 vs. 1.49; p < 0.01). Clinical outcome in GOS scale in patients with SAH and CIA was significantly worse than in SAH and nCIA (2.86 vs. 4.06; p = 0.04).

Conclusions:
To conclude, proposed criteria of CIA should be taken into consideration during diagnosis and qualification to invasive treatment. Classifying aneurysm as CIA is related to greater possibility of aborting endovascular procedure due to technical difficulties.