The Relationship between Neck Size of the Cerebral Saccular Aneurysms and Outcome after Endovascular Intervention

Abstract
Background: Intracranial aneurysms are common with a prevalence of 0.2% to 9% in adults. Intracranial aneurysms have high mortality and morbidity, so exclusion of aneurysms from cerebral circulation is aimed with established endovas-cular embolization.
Aim of Study: Is to report our experience in managing intracranial aneurysms using coil embolization and to report the relation between neck size of cerebral aneurysms, its relation to dome height which is defined as Aspect Ratio (AR), and clinical, angiographic outcome after endovascular intervention.
Patients and Methods: From July 2015 to May 2017, a series of 40 nonrandomized consecutive patients (mean age: 44.2±14.9 years) with 42 intracranial aneurysms underwent endovascular coil embolization in our center. We excluded patients with H & H grade 5 on admission and patients with
H & H grade 4 were managed conservatively until improve-ment with better H&H grade. All patients were evaluated by four-vessel angiography to determine the shape, size, number and location of the aneurysms. Degree of aneurysm occlusion were assessed according to modified Raymond Roy classifi-cation. The cases were divided according to neck size, 4mm being the discriminative value for small and wide necks and divided according to aspect ratio into AR >2, AR 1.5-2, AR 1-1.5, AR <1. The post coiling angiogram of each case was analyzed to evaluate the degree of occlusion achieved by the technique, clinical outcome was assessed by Glasgow Outcome Scale (GOS).
Results: Immediately after the procedure, Raymond class
I with total occlusion was seen in 26 (61.9%), Raymond class II with subtotal occlusion in 10 (23.8%), and incomplete occlusion with Raymond class IIIa in 4 (9.5%) and Raymond class IIIb in 2 (4.8%) aneurysms. There was significant relationship between the aneurysm neck size and aspect ratio with degree of occlusion. In the small necked groupand AR >1.5 with modified Raymond classification are; class I was achieved in 22 (68.8%) aneurysms, class II in 8 (25%) aneu-rysms, class IIIa in one (3.1%) aneurysm, class IIIb in one (3.1%) aneurysm. The wide necked group and AR <1.5 pro-vides different results, class I was achieved in 4 (40%) aneurysms, class II in 2 (20%) patients, class IIIa in 3 (30%) aneurysms and class IIIb in one (10%) aneurysm. Six patients (15%) experienced some complication during the procedure, including two aneurysms perforation, two thromboembolic events and two device induced vasospasm. Thirty four patients with 36 aneurysms who underwent follow-up for 6 months, 29 (80.6%) aneurysms with no change, five (13.8%) had recanalization and two (5.6%) had more thrombosis.
Conclusion: Endovascular coiling was an effective and safe technique for treatment of cerebral aneurysms showing a high cure rate as a single treatment modality in aneurysms with small neck size and AR >1.5, but in aneurysms with wide neck and AR <1.5, it is beneficial when assisted with additional forms of endovascular intervention (balloon, stent or flow diverters) for better treatment and improving outcome of the cases. Low aspect ratio plays a more dominant role than neck diameter in predicting the need for adjunctive techniques in the coiling of intracranial aneurysms.