Aneurysm Isolation is Associated with Complete Occlusion of Aneurysms After Flow Diverter Treatment.

PURPOSE: Some aneurysms remain patent after treatment with flow diverters (FD) due to residual blood flow in the aneurysm. Several studies have proposed that branches and residual flow are associated with delayed aneurysm occlusion. We propose that aneurysm isolation (i.e., the complete disconnection of the aneurysm from surrounding vessels) might be a possible factor facilitating aneurysm occlusion. This study aimed to determine if aneurysm isolation was a factor associated with aneurysm occlusion after FD treatment. METHODS: We reviewed 80 internal carotid artery (ICA) aneurysms treated with FDs between October 2014 and April 2021. Aneurysm isolation was assessed in high-resolution cone-beam computed tomograms at the end of each treatment. Aneurysms with incorporated branches and those with connections to other branches due to stent malapposition were deemed to be nonisolated. Other factors, such as patient age, sex, anticoagulant use, aneurysm size, adjunct coil use, and the presence of incorporated branches, were considered. The degree of aneurysm occlusion (complete or incomplete) was assessed by follow-up angiograms 12 months after treatment. RESULTS: Complete occlusion was achieved in 57 of 80 aneurysms (71%). Completely occluded aneurysms had a significantly higher ratio of isolation compared to incompletely occluded aneurysms (91.2% vs. 69.6%, P = 0.032). Multivariate logistic regression analysis showed that aneurysm isolation was the sole significant predictor of complete aneurysm occlusion (odds ratio, OR 19.38; 95% confidence interval, CI 2.280-164.657; P = 0.007). CONCLUSION: Aneurysm isolation is a significant factor contributing to complete occlusion after FD treatment.

Efficacy of a Novel Augmented Reality Navigation System Using 3D Computer Graphic Modeling in Endoscopic Transsphenoidal Surgery for Sellar and Parasellar Tumors.

In endoscopic transsphenoidal skull base surgery, knowledge of tumor location on imaging and the anatomic structures is required simultaneously. However, it is often difficult to accurately reconstruct the endoscopic vision of the surgical field from the pre-surgical radiographic images because the lesion remarkably displaces the geography of normal anatomic structures. We created a precise three-dimensional computer graphic model from preoperative radiographic data that was then superimposed on a visual image of the actual surgical field and displayed on a video monitor during endoscopic transsphenoidal surgery. We evaluated the efficacy of this augmented reality (AR) navigation system in 15 consecutive patients with sellar and parasellar tumors. The average score overall was 4.7 [95% confidence interval: 4.58-4.82], which indicates that the AR navigation system was as useful as or more useful than conventional navigation in certain patients. In two patients, AR navigation was assessed as less useful than conventional navigation because perception of the depth of the lesion was more difficult. The developed system was more useful than conventional navigation for facilitating an immediate three-dimensional understanding of the lesion and surrounding structures.

Ventral Clival Branch of the Ascending Pharyngeal Artery as a Transosseous Feeder of an Arteriovenous Fistula Surrounding the Clival Lesions.

PURPOSE: Arteriovenous fistulas (AVFs) adjacent to the clivus, such as cavernous sinus dural AVFs (CSDAVFs) and condylar AVFs, sometimes have an intraosseous shunted pouch and recruit blood supply from transosseous feeders. Precise analysis of transosseous feeders regarding the clival lesion has not yet been performed. Therefore, this study aimed to clarify the characteristics and identity of transosseous feeders in clival lesions. METHODS: Patients with CSDAVFs and condylar AVFs, who underwent high-resolution cone-beam computed tomography or three-dimensional rotational angiography in our institute, were included. The frequency, type of branch, penetrating point, and termination of intraosseous feeders were retrospectively evaluated. RESULTS: A total of 31 patients with 36 lesions in CSDAVFs and 8 patients with 8 lesions in condylar AVFs underwent angiography. For CSDAVFs, 38 transosseous feeders were detected in 23 out of 31 patients, including 22 in the pharyngeal branch of the ascending pharyngeal artery (APhA), 6 in the hypoglossal branch of the APhA, 6 in the accessory meningeal artery, 3 in the meningohypophyseal trunk (MHT), and 1 in the anterior branch of the middle meningeal artery. For condylar AVFs, 24 transosseous feeders were detected in all 8 patients, including 11 in the pharyngeal branches of the APhA, 7 in the hypoglossal branch of the APhA, 6 in the segmental artery from the vertebral artery, and 2 in the MHT. CONCLUSION: Transosseous feeders of AVFs around the clivus, which are frequently seen in AVFs of this area, mainly arise from ventral clival branches and from pharyngeal branches of the APhA.

Intracranial ancient schwannoma originating from vestibular nerve: A case report and review of the literature.

Background: Ancient schwannoma (AS) is a subtype of schwannoma with degenerative features, which often progresses slowly over a long period of time. Intracranial AS is a rare benign tumor and there are no detailed reports of AS originating from the vestibular nerve. Case Description: Herein, we present the case of a patient with the right vestibular schwannoma with multiple meningiomas and review three previous cases of intracranial AS. Near-total resection was performed for vestibular schwannoma and the pathological findings were AS (World Health Organization Grade I). Five months postoperatively, gamma knife radiosurgery was performed for a recurrent lesion of the right vestibular schwannoma in the internal auditory meatus. Although AS is known to be a benign pathology, there are cases of rapid growth and early recurrence, as the one presented here. The high Ki-67 index (up to 5%) and the presence of cysts may be related to the rapid progression of intracranial AS. Conclusion: Therefore, careful follow-up is necessary even if adequate removal is achieved. In addition to pathological studies, the genetic background of intracranial AS warrants future investigations. Further accumulation of cases is necessary to clarify the clinical features of intracranial AS.

Acute Ischemic Stroke Due to Basilar Artery Occlusion with Coronavirus Disease 2019: A Case Report.

Although it is increasingly recognized that coronavirus disease 2019 (COVID-19) can cause multi-organ disease, including acute ischemic stroke, the incidence of coagulation disorder is reported to be lower in Asian countries. We report a case of a 47-year-old Asian man with mild COVID-19 respiratory symptoms who had acute basilar artery occlusion. Despite successful recanalization with mechanical thrombectomy, the patient developed extensive cerebral infarction in the posterior circulation, necessitating decompressive craniotomy. Our findings suggest that severe large vessel occlusion (LVO) can occur even in young Asian patients with mild COVID-19 respiratory symptoms and that its outcome can be extremely severe despite successful recanalization. The management of COVID-19-related LVO can be very challenging, as both the prevention of possible nosocomial infection and early recanalization are required simultaneously.

[Usefulness of CT in the Lateral Decubitus Position for Preoperative Evaluation of Cranioplasty].

Patients with massive brain swelling undergo external decompressive craniectomy to manage intracranial pressure. Following supratentorial craniectomy, and after the brain swelling is relieved, cranioplasty is performed. Although feasibility of the surgery is usually assessed by CT scanning in a supine position, it is sometimes difficult to determine whether the surgery can be performed safely. Although nine patients underwent a decompressive craniectomy during the study period, only six patients could undergo brain CT-first in a supine position and next in a lateral decubitus position with the surgical side upward-before cranioplasty. On CT images, the distance from the midline to the brain surface was measured on the image where brain bulging was maximal, and the bulging was calculated by comparing the image with the distance measured on the contralateral side. In all cases, brain bulging decreased with this change in position. The decrease ranged from 5.5-9.2mm(mean 7.1mm). Patients with brain bulging of 2.8-3.6mm in the lateral decubitus position needed no additional procedure, or only required drainage of a very small amount of cerebrospinal fluid(CSF)from the brain surface. Those with brain bulging of 5.1-12mm showed ventricular dilatation on CT images, and required ventricular puncture or spinal CSF drainage to decrease brain bulging for cranioplasty. We believe that the lateral decubitus position, with the surgical side upward, ameliorates the local brain shift induced by gravity. A lateral position during CT simulates the surgical head position for cranioplasty and can help to assess whether cranioplasty is feasible.