Introduction 1 2 3 18 The aim of this retrospective study was to determine the incidence, clinical presentation and midterm clinical and imaging results of endovascular treatment of 35 patients with 36 SCA aneurysms. Methods Patients 1 Fig. 1 a b  The clinical condition of the 22 patients with a ruptured SCA aneurysm at the time of treatment was HH I–II in 16, HH III in 3 and HH IV–V in 3. Seven SCA aneurysms in six patients were additional to another ruptured aneurysm and were coiled in the same session as the ruptured aneurysm. The clinical condition of these six patients was HH I–II in five and HH IV–V in one. 2 Fig. 2 a short single arrow long single arrow pair of arrows b c d  Coiling procedure Coiling of aneurysms was performed on a biplane angiographic unit (Integris BN 3000 Neuro, Philips Medical Systems, Best, The Netherlands) with the patient under general anaesthesia and systemic heparinization. Heparin was continued intravenously or subcutaneously for 48 h after the procedure, followed by low-dose aspirin for 3 months orally. Coiling was performed with Guglielmi detachable coils (GDC, Boston Scientific, Fremont, Calif.) or TruFill DCS coils (Cordis, Miami, Fl.). The aim of coiling was to pack the aneurysm as densely as possible, until not a single additional coil could be placed. Four wide-necked aneurysms (12%) were coiled with the aid of a supporting balloon in the basilar artery. One aneurysm was located distal on the SCA and was selectively occluded with coils sparing the parent SCA. Complications of coiling were recorded. Initial angiographic results of coiling were classified as complete occlusion (100%), near complete occlusion (90–100%) and incomplete occlusion (<90%). Clinical and angiographic follow-up Patients who survived the hospital admission period were scheduled for a follow-up visit in the outpatient clinic 6 weeks after treatment and for follow-up angiography after 6 and 18 months. Neurological status according to the Glasgow Outcome Scale (GOS) was evaluated at every outpatient clinic visit and at every admission for follow-up angiography. The results of follow-up angiography were classified in the same way as for initial angiographic results. Results Initial angiographic results and complications 3 Fig. 3 a b c d  Clinical follow-up Clinical follow-up was available for all 33 patients. One patient died of a procedural rupture and another patient died of diffuse vasospasm after subarachnoid haemorrhage (SAH). The remaining 31 patients had clinical follow-up of mean 45 months (median 44.5 months, range 4–103 months, 118 patient-years). Outcome at 6 months follow up of these 31 patients was GOS 5 in 26 (84%), GOS 4 in 4 (13%) and GOS 3 in 1 patient (3%). Symptoms of mass effect on cranial nerves in four patients were cured in all. During extended follow up, two patients died of unrelated disease 3 and 6 years after coiling of a SCA aneurysm: pulmonary embolism in one patient and disseminated bronchial carcinoma in the other patient. There were no episodes of (re)bleeding during the 118 patient-years of follow-up. Angiographic follow-up Of the 31 surviving patients, 4 refused follow-up angiography. The remaining 27 patients (with 28 SCA aneurysms) all had 6 months follow-up angiography and 19 had extended angiographic follow-up of a mean of 31 months (median 22 months, range 18–84 months). Stable complete or near-complete occlusion was apparent in 25 of 28 aneurysms. In one patient, a 66-year-old man with a 27-mm partially thrombosed SCA aneurysm presenting with trigeminal neuralgia, the coils had migrated into the intraluminal thrombus at the 6-month follow-up angiography. However, the trigeminal neuralgia was cured and the aneurysm was not retreated. The patient died 6 years later of disseminated bronchial carcinoma. Two aneurysms in two patients that were initially incompletely occluded (both 80% occlusion) remained so at extended angiographic follow-up. Additional treatment was judged impossible in both patients. Discussion 3 19 10 11 4 12 15 20 22 While surgery for SCA aneurysms is often difficult, limited to good-grade patients and associated with substantial morbidity, coiling is technically easy and can also be performed in the acute phase of haemorrhage in bad-grade patients. This makes coiling the method of choice to treat SCA aneurysms. Conclusion SCA aneurysms are rare with an incidence of 1.7% of treated aneurysms at our institution. There is a frequent association with aneurysms at other locations. Most patients present with SAH. Since the SCA is closely related to cranial nerves III, IV and V, some aneurysms present with palsies of these nerves. Endovascular occlusion with detachable coils is feasible with good angiographic and clinical results.