Tandem intracranial aneurysms are aneurysms located along a single intracranial vessel. Adjacent tandem aneurysms arise within the same vascular segment and their presence often suggests diffuse parent vessel anomaly. Endovascular management of these rare lesions has not been well studied. In this retrospective observational study, we describe our experience treating adjacent tandem intracranial aneurysms with endovascular embolization.

We retrospectively reviewed records of patients with these lesions who underwent endovascular treatment between 2008 and 2013.

Thirteen patients (mean age 60.8 years; 12 women) with 28 adjacent tandem aneurysms were treated during the study timeframe. Aneurysms were located along the clinoidal, ophthalmic, and communicating segments of the internal carotid artery in 12 patients and at the basilar apex in one patient. Average size was 8.4 mm. Six patients (12 aneurysms) were treated by flow diversion via the Pipeline embolization device (PED) and seven (16 aneurysms) by stent-assisted coiling, with coils successfully placed in 11 aneurysms. Clinical follow-up was available for an average of 26.1 months; postprocedural angiography was performed for 12 patients. Complete occlusion was achieved in nine of ten (90 %) PED-treated aneurysms and eight of 11 (72.7 %) treated by stent-assisted coiling (p = 0.44). Two patients treated by stent-assisted coiling required re-coiling for aneurysm recanalization. Overall, modified Rankin scale scores were 0–1 for 12 patients and 3 for one patient.

Adjacent tandem intracranial aneurysms can be safely and effectively treated by either stent-assisted coiling or flow diversion. We prefer PED flow diversion due to better parent vessel reconstruction and lower recanalization risk.