Fusiform superior cerebellar artery aneurysm treated with STA-SCA bypass and trapping

Trapping and side-to-end superior cerebellar artery to superior cerebellar artery bypass for treatment of fusiform superior cerebellar artery aneurysm

We describe the technical nuances of in-situ bypass for treatment of a fusiform superior cerebellar artery (SCA) aneurysm via surgical trapping and a side-to-end in-situ bypass between duplicated SCAs. Our patient is a 40-year-old male who presented with an incidental aneurysm of the proximal right superior cerebellar artery (SCA). Formal angiography was performed that demonstrated a fusiform morphology of the aneurysm, as well as a duplicated SCA on that side. After extensive counseling, the patient elected to undergo surgical clip reconstruction with possible bypass. A large frontotemporal craniotomy was performed and a combined transsylvian-subtemporal approach to the ventral anterolateral brainstem was performed. After identifying the aneurysm, the tentorium was incised posterior to the insertion of the trochlear nerve to widen the operative field. An end-to-side anastomosis between the duplicated SCAs was performed, followed by trapping of the diseased arterial segment. The patient had an oculomotor nerve palsy post-operatively, however this resolved by his six-month follow-up. In-situ bypass is a viable technique for revascularizing the SCA territory during clip reconstruction of fusiform aneurysms. A duplicated SCA allows for an SCA to SCA bypass. Incising the tentorium can increase visualization of donor and recipient vessels and facilitate performance of the anastomosis.

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.

Advantages of petrosectomy for superficial temporal artery to superior cerebellar artery bypass based on three-dimensional distance measurements using cadaver heads

Superficial temporal artery (STA) to superior cerebellar artery (SCA) bypass is usually performed via the subtemporal approach (StA), anterior transpetrosal approach (ApA), or combined petrosal approach (CpA), but no study has yet reported a quantitative comparison of the operative field size provided by each approach, and the optimal approach is unclear. The objective of this study is to establish evidence for selecting the approach by using cadaver heads to measure the three-dimensional distances that represent the operative field size for STA-SCA bypass. Ten sides of 10 cadaver heads were used to perform the four approaches: StA, ApA with and without zygomatic arch osteotomy (ApA-ZO^- and ApA-ZO⁺), and CpA. For each approach, the major-axis length and the minor-axis length at the anastomosis site (La-A and Li-A), the major-axis length and the minor-axis length at the brain surface (La-B and Li-B), the depth from the brain surface to the anastomosis site (Dp), and the operating angles of the major axis and the minor axis (OAa and OAi) were measured. Shallower Dp and wider operating angle were obtained in the order CpA, ApA-ZO⁺, ApA-ZO^-, and StA. In all parameters, ApA-ZO^- extended the operative field more than StA. ApA-ZO⁺ extended La-B and OAa more than ApA-ZO^-, whereas it did not contribute to Dp and OAi. CpA significantly decreased Dp, and widened OAa and OAi more than ApA-ZO⁺. ApA and CpA greatly expanded the operative field compared with StA. These results provide criteria for selecting the optimal approach for STA-SCA bypass in light of an individual surgeon's anastomosis skill level.

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

Background

Fusiform superior cerebellar artery (SCA) aneurysms are rare, and their management represents a technical challenge. In complex aneurysms, endovascular parent vessel occlusion of the SCA may be a treatment option. Here, we present 2 cases of fusiform SCA aneurysms, 1 ruptured and 1 unruptured, as well as our institution's management with parent vessel occlusion. We also provide a review of the literature.

Cases Description

Case 1: A 42-year-old male was transferred from an outside hospital with subarachnoid hemorrhage. On admission, the patient had a Glasgow Coma Scale score of 8, a Hunt and Hess grade 4, and a Fisher grade 4. A diagnostic angiogram demonstrated a right SCA fusiform lesion with proximal and distal dilatations of 1.45 mm and 5.35 mm long, respectively, likely representing a single dissecting pseudoaneurysm. The distal dilatation was coiled, resulting in parent vessel occlusion. The patient recovered clinically and was discharged in stable condition.

Case 2: A 27-year-old female was transferred from an outside hospital due to a brainstem stroke. A diagnostic angiogram revealed an S2/S3 segment left SCA fusiform lesion, likely representing a dissecting aneurysm. The patient was neurologically intact at admission and managed conservatively. At the 2-month follow-up angiogram, the dissection had extended along the length of the SCA. Consequently, the patient underwent coil embolization of the distal left SCA. At the 6-month follow-up, the vessel remained obliterated and the patient's neurologic status had improved.

Conclusions

Endovascular coil embolization of fusiform SCA aneurysms offers a reasonable and safe treatment approach.

Fusiform Superior Cerebellar Artery Aneurysm Treated with Endovascular Treatment

An aneurysm of the distal superior cerebellar artery (SCA) is a highly rare disease. Fusiform aneurysms of the distal SCA are particularly challenging to treat. Clipping, trapping with or without bypass using microsurgery or endovascular treatment (EVT) were used to treat this condition. We describe the case of fusiform distal SCA aneurysms treated successfully with endovascular coiling with a 3-month follow-up. A 39 year-old male was presented with subarachnoid hemorrhage (SAH) and a 15 mm fusiform aneurysm of the ambient segment of the left distal SCA. EVT for parent artery occlusion and packing of the aneurysm was done. Left sixth nerve palsy appeared after 1 day of EVT. The symptom completely recovered within 1 week of the post-procedural period. No neurological deficit was seen during the clinical 3-month follow-up. EVT of fusiform distal SCA aneurysms with coils is a safe and feasible option to manage this rare condition. However, the treatment options must be carefully selected depending on the neurologic condition, development of collateral circulation, and configuration of the dissection.

State-of-art in surgical treatment of dissecting posterior circulation intracranial aneurysms

Vertebrobasilar (VB) intracranial dissecting aneurysms (IDAs) pose difficult therapeutic issues and are especially among the most difficult to manage surgically. There are, however, some cases where selective aneurysm obliteration by endovascular approach is impossible or is associated with an unacceptable risk of morbidity. This is particularly true when the aneurysm is dissecting, giant, or has a large neck. In such cases, surgical treatment may be the only alternative. Optimal management of these lesions is therefore challenging and treatment decisions have to be made on a case-by-case basis. Ideal treatment should be a complete surgical excision of the lesion; however, this procedure might only be possible after distal and proximal vessel wall occlusion which might not be tolerated by the patient depending on the location of the aneurysm. Therefore, formulation of recommendations concerning the surgical strategy remains still difficult due to inconsistency of surgical outcomes. The literature describing surgical strategy of VB IDAs is varying in quality and content, and many studies deal with only a few patients. In the presented review, the authors summarize the current knowledge on the incidence, pathogenesis, clinical presentation, and diagnostic procedures with special emphasis on surgical treatment of IDAs in posterior circulation.