Distal Parent Vessel Occlusion of 2 Superior Cerebellar Artery Fusiform Aneurysms: Report of 2 Cases and Literature Review

The Superior Cerebellar Artery: Variability and Clinical Significance

The superior cerebellar artery (SCA) arises from the distal part of the basilar artery and passes by the oculomotor, trochlear, and trigeminal nerves. SCA is known to play a crucial role in the development of trigeminal neuralgia. However, due to its anatomical variability, it may also trigger other neurovascular compression (NVC), including hemifacial spasm, oculomotor nerve palsy, and ocular neuromyotonia. Additionally, it may be associated with ischemic syndromes and aneurysm development, highlighting its clinical significance. The most common anatomical variations of the SCA include duplication, a single vessel origin from the posterior cerebral artery (PCA), and a common trunk with PCA. Rarely observed variants include bifurcation and origin from the internal carotid artery. Certain anatomical variants such as early bifurcation and caudal course of duplicated SCA trunk may increase the risk of NVC. In this narrative review, we aimed to examine the impact of the anatomical variations of SCA on the NVCs based on papers published in Pubmed, Scopus, and Web of Science databases with a snowballing approach. Our review emphasizes the importance of a thorough understanding of the anatomical variability of SCA to optimize the management of patients with NVCs associated with this artery.

Ruptured aneurysms at the distal superior cerebellar artery successfully treated by combining occipital artery-superior cerebellar artery anastomosis and endovascular therapy: illustrative case

BACKGROUND

Distal superior cerebellar artery (SCA) aneurysms are rare and are treated using various treatment strategies. Treatment often requires parent artery occlusion, which raises concerns regarding the potential risk of ischemia in the distal territory.

OBSERVATIONS

An 81-year-old woman presented with subarachnoid hemorrhage. Diagnostic cerebral angiography revealed two tiny distal SCA aneurysms. Because significant ischemic damage following parent artery occlusion was concerned, two bypasses between the occipital artery and SCA branches were first performed with the patient in the prone position in a hybrid operating room. Each aneurysm was successively treated in the same position with endovascular internal trapping and intra-aneurysmal embolization. After adequate hemostasis was confirmed, the wound was closed. Both aneurysms were successfully occluded without symptomatic ischemic complications.

LESSONS

This combined surgical and endovascular approach would be helpful in cases with notable concerns regarding ischemia after sacrificing the parent artery.

Ruptured peripheral superior cerebellar artery dissecting aneurysms associated with primitive trigeminal artery: a case report

Background

Persistent primitive trigeminal artery (PPTA) is a remnant of the carotid-vertebrobasilar anastomoses in the embryo. Although PPTAs are discovered incidentally in most cases, altered hemodynamics may lead to increased risk of stroke. To the best of our knowledge, no reports of PPTA associated with superior cerebellar artery (SCA) dissecting aneurysms have been published in the English language.

We describe the case of a patient who presented with subarachnoid hemorrhage (SAH) due to ruptured peripheral SCA dissecting aneurysms in association with PPTA. Additionally, we discuss the relationship between PPTA and peripheral SCA aneurysms and the treatment of peripheral SCA aneurysms.

Case presentation

A 43-year-old woman presented with acute onset of headache and nausea and admitted to our hospital. She was diagnosed with SAH due to ruptured left SCA dissecting aneurysm(s) and had undergone digital subtraction angiography. The left vertebral angiography showed aneurysmal dilatations of the left S2 segment (lateral pontomesencephalic segment) along with dissection through the segments of S2 and S3 (cerebellomesencephalic segment). It also showed ipsilateral PPTA. The left vertebral artery (VA) had normal caliber and the basilar artery segment proximal to the orifice of the left PPTA was not hypoplastic. The patient underwent proximal parent artery occlusion at the S2 segment via the left VA and was successfully treated with no neurological deficits having lasted 5 months.

Conclusions

The flow alteration with PPTA may have influenced the formation of SCA dissection in this patient. Further studies are needed to understand the etiology and treatment outcomes of peripheral SCA aneurysms better.

Tentorial Branch of the Superior Cerebellar Artery with Retrograde Flow to Partially Thrombosed Large Superior Cerebellar Artery Aneurysm

BACKGROUND

Although the tentorial branch of the superior cerebellar artery (SCA) was reported to be a frequent finding in living subjects in 1 study, its clinical relevance, especially in surgery for aneurysms, has not been elucidated. We present our experience with the tentorial branch of the SCA identified during surgical intervention of a distal SCA aneurysm and discuss its clinical relevance.

CASE DESCRIPTION

A 71-year-old woman presented with cerebral infarction in the SCA area, and a partially thrombosed, large, fusiform aneurysm was found in the lateral pontomesencephalic segment of the SCA. Despite trapping of the aneurysm, arterial flow was observed on postprocedural Doppler flow examination and indocyanine green angiography. Careful inspection of the area led to the identification of a small tentorial branch of the SCA as a retrograde feeder. Coagulation of the artery led to the successful completion of the trapping. Postoperatively, the patient did not develop new neurologic deficits.

CONCLUSIONS

This is the first report to our knowledge of a clinical association of the tentorial branch of the SCA with a distal SCA aneurysm, which played an important role in achieving complete obliteration of the aneurysm. The recognition of this small artery is potentially important for successful cure of distal SCA aneurysms.