Background/Objectives: Non-saccular aneurysms are a rare subtype of intracranial aneurysms with complex morphologies. Although treatment strategies for ruptured non-saccular and saccular aneurysms differ significantly, large-scale comparisons of the outcomes between the two types remain limited. We aimed to compare the clinical characteristics, procedure-related complications, and functional outcomes between patients with subarachnoid hemorrhage (SAH) caused by non-saccular or saccular aneurysms. Methods: We retrospectively analyzed 1176 consecutive patients with aneurysmal SAH from a population-based stroke registry in Kochi Prefecture, Japan. Aneurysms were classified as saccular or non-saccular based on the morphology, and clinical variables, radiological features, and treatment modalities were compared. Additionally, 840 patients who underwent intervention for their aneurysms within 3 days of onset were further investigated to evaluate the impact of the non-saccular aneurysm shape on poor functional outcomes, defined as a modified Rankin Scale score ≥ 3 at discharge. Results: Non-saccular aneurysms were more common in younger patients and located in the posterior circulation. Procedure-related ischemic complications were more likely to occur in non-saccular aneurysms than in saccular aneurysms (odds ratio [OR]: 2.57, 95% confidence interval [CI]: 1.56–4.97, p < 0.001). In a multivariable logistic regression analysis, a non-saccular morphology was an independent risk factor of poor outcomes (OR: 2.92, 95% CI: 1.34–6.32, p = 0.007) after adjustment for potential confounders. Interaction and subgroup analyses revealed that the negative effects of non-saccular aneurysms on functional outcomes were more prominent in younger patients aged ≤ 60 years. Conclusions: Non-saccular aneurysms are independently associated with ischemic complications and poor outcomes after SAH, particularly in younger patients.

Background: Flow diverter (FD) placement is generally effective for intractable internal carotid artery (ICA) aneurysms. However, salvage treatment for the aneurysm enlarging even after FD placement remains to be elucidated. Additional overlapping FD placement is considered the first-line treatment for residual or recurrent aneurysms. However, it is unclear whether overlapping FD is also effective for enlarging giant aneurysms that are considered impending rupture status. Although parent artery occlusion is a promising option, treatment strategy must be optimized, especially when a critical perforating artery is involved. Case Description: A 74-year-old woman experienced rapid symptomatic growth of her giant supraclinoid ICA aneurysm 10 months after FD placement. We assumed that reinforcement of flow diverting effect alone would be less effective for this extremely intractable aneurysm with more aggressive clinical feature so that surgical bailout by parent artery occlusion was planned. Complete ICA obliteration underneath the aneurysm was unavailable due to the presence of anterior choroidal artery. Thus, we took a flow alteration strategy, where we created minimal retrograde flow through the parent artery by a combination of an extracranial-intracranial bypass and targeted endovascular proximal parent artery obliteration, resulting in prevention of aneurysmal rupture and further growth. Conclusion: Impending rupture of the intracranial giant aneurysm after FD placement may be controllable with a tailor-made parent artery occlusion strategy even when a critical perforating artery is involved.

Background/Objectives: Complex aneurysms of the posterior inferior cerebellar artery (PICA) remain challenging because of their deep location, variable morphology, and proximity to critical neurovascular structures. Although endovascular therapy is preferred, its feasibility is limited in wide-necked, fusiform, or dissecting lesions. We describe our tertiary referral hospital single-center experience with tailored microsurgical and endovascular strategies—emphasizing occipital artery–PICA (OA-PICA) bypass, transcondylar fossa craniotomy, and cerebellomedullary fissure opening—and analyze perioperative factors that influence outcome. Methods: All consecutive patients treated for PICA origin or distal-PICA aneurysms between January 2021 and April 2025 were retrospectively reviewed. Demographics, aneurysm characteristics, procedure type, antithrombotic regimen, complications, diffusion-weighted MRI findings, and 3-month modified Rankin Scale scores were collected. Results: Twelve aneurysms (mean age 61.4 ± 15.2 years; 8 women) were treated: trapping + OA-PICA bypass in 5, direct clipping in 2, flow diverter in 1, endovascular parent artery occlusion in 2, coil embolization in 1, and a hybrid bypass-plus-coil strategy in 1. Two cases were ruptured aneurysms. Perioperative aspirin was used in 2/5 bypass cases; heparin was added in one hybrid case. Asymptomatic PICA-territory infarcts occurred in the three bypasses performed without antiplatelet therapy (one with intra-anastomotic thrombus). No leaks or subcutaneous collections of cerebrospinal fluid were encountered, and no graft occlusions were observed. At 3 months, 9/12 patients achieved a good outcome (mRS 0–2); among them, only one patient with subarachnoid hemorrhage (SAH) experienced postoperative worsening of the mRS. Two cranial nerve palsies (one permanent, one transient) and one wound site hematoma (heparin-associated) resolved without sequelae. Conclusions: Meticulous operative planning allows safe treatment of complex PICA aneurysms. Perioperative aspirin appears beneficial for OA-PICA bypass, whereas perioperative heparin increases bleeding risk. Individualized selection of endovascular, microsurgical, or combined strategies yields favorable early neurological outcomes in this demanding subset of cerebrovascular disease.

Background/Objectives: Clazosentan reduces cerebral vasospasm and delayed cerebral ischemia following aneurysmal subarachnoid hemorrhage (aSAH). However, concerns that clazosentan may cause cerebral edema and increase intracranial pressure (ICP) have discouraged its use in patients with poor-grade aSAH. Methods: This single-center retrospective study included 59 patients with aSAH who underwent continuous direct ICP monitoring, of whom 23 received clazosentan and 24 received fasudil. Most clazosentan-treated patients had poor-grade aSAH (WFNS 4–5, 95.7%). The primary outcome was the change in mean daily ICP in the clazosentan group between the pre-treatment and full treatment periods, with a secondary analysis restricted to the first 7 days and stratified by the presence of intracerebral hematoma (ICH). Cerebral perfusion pressure (CPP) changes were assessed as secondary outcomes, and the fasudil group served as an exploratory comparator. Results: Among 21 clazosentan-treated patients available for primary analysis, median ICP did not change significantly between the pre-treatment and treatment periods (6.4 vs. 8.4 mmHg; median ΔICP +0.5 mmHg, 95% CI −1.74 to +2.64; p = 0.708), a finding consistent in the first 7 days and across subgroups by ICH status. In contrast, CPP increased significantly between the pre-treatment and treatment periods (69.1 vs. 84.5 mmHg; median ΔCPP +14.0 mmHg, 95% CI +8.93 to +17.44; p < 0.001). Conclusions: In this retrospective single-center cohort, no statistically significant ICP elevation was observed during clazosentan administration under standard neurosurgical management. Although the small sample size limits statistical power and a false-negative result cannot be excluded, these findings may help inform clinical decision-making regarding clazosentan use in patients with poor-grade aSAH.