3 mm以下の破裂小型動脈瘤によるくも膜下出血の特徴と治療成績

抄録

Background: Surgical clipping is considered the primary option for ruptured small aneurysms (s-AN; 3 mm or less), because coiling has been associated with a relatively high risk of procedural error. With the advent and development of coiling techniques and materials, several studies showed that coiling of a ruptured s-AN can be performed with acceptable risk. However, the best management strategy for a ruptured s-AN remains unknown.
Objective: The aim of this study was to assess the outcomes of ruptured s-ANs in patients who underwent surgical clipping, and to identify the clinical characteristics of these aneurysms.
Patients and Methods: In total, 237 patients who presented with aneurysmal subarachnoid hemorrhage (SAH) between April 2008 and March 2015 were evaluated. Aneurysms were classified as small (≤3.0 mm), medium (3.0 mm ≤ 12.0 mm), large (12.0 mm ≤ 25.0 mm), and giant (≥25.1 mm), based on their largest dimensions. Various factors were analyzed, including the preoperative Hunt and Kosnik grade and Fisher groups, the aneurysmal location, multiplicity, and procedural complications. Clinical outcomes were assessed using the Glasgow Outcome Scale (GOS) at the time of discharge. In the case of multiple aneurysms, we identified the ruptured aneurysm based on its bleeding pattern on computed tomography (CT) or on surgical findings.
Results: In 28 (11.8%) of 237 patients, an s-AN was identified as the lesion responsible for the SAH. The most frequent site of a ruptured s-AN was the anterior communicating artery. In a comparison with larger aneurysms, ruptured s-ANs were significantly more common in the pericallosal artery, internal carotid-anterior choroidal artery, and vertebral-posterior inferior cerebellar artery bifurcation, but less so in the middle cerebral artery. There were no procedure-related complications during the clipping of ruptured s-ANs. The clinical outcomes (GOS) of 28 patients with ruptured s-ANs were as follows: good recovery (GR) 17 (60.7%), moderate disability (MD) 6 (21.4%), severe disability (SD) 0 (0%), vegetative state (V) 1 (3.6%), and death (D) 4 (14.3%). Thus, the overall outcomes of ruptured s-ANs were significantly better compared with outcomes of larger aneurysms: GR 106 (50.7%), MD 48 (23.0%), SD 18 (8.6%), V 7 (3.4%), and D 30 (14.4%). In 43 (18.1%) of 237 patients, multiple aneurysms were identified. The largest aneurysm had not ruptured in 10 (23.3%), and an s-AN had ruptured in 6 (14.0%) of the 43 patients with multiple aneurysms.
Conclusion: Surgical clipping for ruptured s-ANs was not associated with procedural complications, but the overall outcomes were similar to those reported for coiling. Considering its ability to identify correctly the rupture site in cases with multiple aneurysms, surgical clipping remains an invaluable treatment strategy.