Superficial Temporal Artery-superior Cerebellar Artery Research Articles

Superficial temporal artery-superior cerebellar artery bypass and direct clipping of a large unruptured superior cerebellar artery aneurysm through subtemporal approach: Surgical video

Background:Superior cerebellar artery (SCA) aneurysms are rare. Current treatments include: direct clipping, trapping ± bypass, and endovascular methods (coiling, stenting, or flow diversion). Due to specific characteristics (wide base, location, and shape), a major challenge while dealing with SCA aneurysms is to preserve the flow of the parent artery and perforators. This video demonstrates a revascularization procedure, and clip reconstruction of a large unruptured basilar artery (BA)/SCA aneurysm performed through the subtemporal approach.Case Description:A 60-year-old woman presented with dizziness and headaches. Computed tomography angiography (CTA) and digital subtraction angiography showed a right unruptured large BA/SCA aneurysm. After multidisciplinary discussion, and considering gender, age, risk factors of the patient. Endovascular treatment was considered with a high risk of ischemic complications. Therefore, the patient was consented for a superficial temporal artery (STA)-SCA bypass through subtemporal approach followed by direct clipping/ trapping of the aneurysm. Postoperative CTA showed occlusion of the aneurysm and patency of the parent vessels. Postoperatively, the patient experienced immediate transient left mild monoparesis and right IV nerve palsy, which recovered completely at 6-months follow-up.Results:Surgical treatment of SCA aneurysms is decreasing due to the existence of endovascular therapies such as stents and flow diverters. However, some cases may necessitate surgical treatment and revascularization procedures to maintain the blood flow of the parent artery and to treat the previous lesion.Conclusion:The STA-SCA bypass through the subtemporal approach is a feasible option to maintain the blood flow of the parent artery in cases of SCA requiring surgical treatment and trapping/direct clipping of the aneurysm.

Surgical Strategies for Ruptured Complex Aneurysms Using Skull Base Technique and Revascularization Surgeries.

Object:Surgical clipping of paraclinoid aneurysm, thrombosed large aneurysm, and/or vertebral-basilar dissecting aneurysms can be very difficult and has relatively high morbidity. We describe our experience using skull base and bypass technique and discuss the advantages and its pitfalls.Patients and Methods:We retrospectively reviewed medical charts of 22 consecutive patients with complex aneurysmal lesions underwent skull base and/or bypass techniques between March 2012 and April 2017.Results:There were 5 patients with paraclinoid or internal carotid artery (ICA) aneurysm underwent modified extradural temporopolar approach with mini-peeling of the dura propria with suction decompression, 3 patients with ICA aneurysm underwent intradural anterior clinoidectomy, 12 patients with vertebral dissecting aneurysm through transcondylar fossa approach (6 patients underwent occipital artery-posterior inferior cerebellar artery [OA-PICA] bypass), 1 patients with vertebral artery dissection underwent superficial temporal artery-superior cerebellar artery and OA-PICA bypass through posterior transpetrosal approach, 1 patient with arteriovenous fistula at the ventral side of the craniovertebral junction through extremely far lateral approach. Surgical outcome was good recovery in 10 patients, moderate disability in 4, severe disability in 4, vegetative state in 2, and dead is 2 patients. The favorable outcome was 63.6%, and poor outcome was 36.4%, which showed poor grade subarachnoid hemorrhagic patients. No patient suffered any complication related to re-rupture and/or incomplete clipping.Conclusion:Skull base technique, which can create a wide and shallow operative space, allowed us to improve surgical outcome and to reduce the risk of intraoperative neurovascular injury for surgical treatment of deeply located complex aneurysms.

Ruptured aneurysm at the cortical segment of the distal posterior inferior cerebellar artery associated with hemodynamic stress after basilar artery occlusion

Background:A distal posterior inferior cerebellar artery (PICA) de novo aneurysm at the cortical segment after atherosclerotic basilar artery occlusion is extremely rare. Here, we report the case of a ruptured distal PICA de novo aneurysm 8 years after basilar artery occlusion.Case Description:A 75-year-old man experienced sudden disturbance of consciousness; computed tomography demonstrated cerebellar and subarachnoid hemorrhage due to a ruptured distal PICA aneurysm. Neck clipping of the aneurysm prevented re-rupture initially, and superficial temporal artery-superior cerebellar artery (STA-SCA) bypass was performed 3 months after admission. Postoperative angiography confirmed patency of the bypass, and the patient was discharged without any new neurological deficits.Conclusion:This report describes a case of de novo development of a saccular distal PICA aneurysm after atherosclerotic basilar artery occlusion. We believe that increased hemodynamic stress at the PICA might have contributed to the occurrence and rupture of the aneurysm. STA-SCA bypass, introduced in the territory of the cerebellar hemisphere, reduces hemodynamic stress, which would prevent the occurrence of de novo aneurysm and recurrent bleeding.

脳底動脈のｄｏｌｉｃｈｏｅｃｔａｓｉａが巨大血栓化脳動脈瘤に移行した１例

A 66-year-old male patient suffered a lacunar infarction 7 years previously and was treated with 100 mg/day of cilostazol. The fluid attenuated inversion recovery (FLAIR) image of a follow-up magnetic resonance imaging (MRI) scan revealed dolichoectasia of the basilar artery with a small luminal thrombus. Thirteen months later, a left cerebellar infarction occurred. The size of the aneurysm and luminal thrombus had increased. The dosage of cilostazol was increased to 200 mg/day. Three weeks later, he suffered a left pontine infarction and 100 mg/day of aspirin was added to the treatment regimen. Seventeen months after the cerebellar infarction, the aneurysm enlarged further. Surgical treatment was performed using a flow reduction method. After anastomoses of the right superficial temporal artery-superior cerebellar artery and left superficial temporal artery-posterior cerebral artery were performed, the bilateral vertebral arteries were embolized using a coil. The patient became comatose 12 hours after the last procedure. Three-dimensional computed tomography angiography revealed the complete occlusion of the basilar artery. Four days later, recanalization of the basilar artery was achieved by using an intravenous urokinase infusion. Nevertheless, marked infarction occurred in the bilateral cerebellar hemispheres and brain stem. He died and an autopsy was performed. The aneurysm was found embedded in the brain stem at autopsy. A microscopic examination showed fragmentation of the internal elastic lamina with atrophy of the muscle layer and adventitia. Neoangiogenesis within the thickened intima may have caused intramural hemorrhage and thrombus formation. Furthermore, a new sickle-shaped clot located between the arterial wall and the old thrombus may have caused the hemodynamic expansion of the aneurysm. Antiplatelet drugs were used to treat ischemic events caused by perforator or branch occlusion. However, use of these drugs should be carefully considered with regards to the risk of potentiating the compression of the brain stem due to aneurysmal enlargement.

Microsurgical anatomy of cerebral revascularization. Part II: Posterior circulation

Revascularization is an important component of treatment for complex aneurysms, skull base tumors, and vertebrobasilar ischemia in the posterior circulation. In this study, the authors examined the microsurgical anatomy related to cerebral revascularization in the posterior circulation and demonstrate various procedures for bypass surgery. The microsurgical anatomy of cerebral and cerebellar vessels as they relate to revascularization procedure and techniques, including extracranial-to-intracranial bypass grafting, arterial interposition grafting, and side-to-side anastomosis, were examined by performing stepwise dissections in 22 adult cadaveric specimens. The arteries and veins in the specimens were perfused with colored silicone. Dominant cerebral and cerebellar revascularization procedures in the posterior circulations include superficial temporal artery (STA)-posterior cerebral artery (PCA), STA-superior cerebellar artery (SCA), occipital artery (OA)-anterior inferior cerebellar artery, OA-posterior inferior cerebellar artery (PICA), and PICA-PICA anastomoses. These procedures are effective in relatively small but critical areas including the brainstem and cerebellum. For revascularization of larger areas a saphenous vein graft is used to create a bypass between the PCA and the external carotid artery. Surgical procedures are generally difficult to perform in deep and narrow operative spaces near critical vital structures. Although a clear guideline for cerebral revascularization procedures has not yet been established, it is important to understand various microsurgical techniques and their related anatomical structures. This will help surgeons consider surgical indications for treatment of patients with vertebrobasilar ischemia caused by aneurysms, tumors, or atherosclerotic diseases in the posterior circulation.

Clinical Analysis of STA-SCA Bypass for Vertebrobasilar Occlusive Disease.

In order to clarify the effectiveness of extracranial- intracranial bypass in cases of vertebro-basilar occlusive disease, we investigated the operative complication, clinical course and follow-up study of 30 cases undergoing superficial temporal artery-superior cerebellar artery (STA-SCA) bypass surgery. Postoperative angiogram showed the patency of the anastomoses in all cases. No serious surgical complications were observed. The outcome on discharge was excellent, with no morbidity and one mortality which was due to cardiac infarction. In the follow-up study, there were four cases with ischemic symptoms, two with transient ischemic attack and two with completed stroke, one of which was a supratentorial infarction due to internal carotid artery occlusion and the other was a small infarction of pons. There were also two deaths due to cardiac infarction and diabetes mellitus. Favorable outcomes were obtained for the remaining cases. The present study suggests that, STA-SCA bypass, can be performed without surgical and systemic complications and used as an effective therapy for vertebrobasilar ischemia.

Vertebrobasilar insufficiency: Stable xenon computed tomography-cerebral blood flow study in posterior circulation revascularization

Preoperative and postoperative local cerebral blood flow were measured by the stable xenon computed tomography-cerebral blood flow technique in 15 patients with vertebrobasilar insufficiency. The surgery included endarterectomy or angioplasty of the vertebral artery (five cases), superficial temporal artery-superior cerebellar artery anastomosis (eight cases), and superficial temporal artery-posterior cerebral artery anastomosis (two cases). Fourteen (93.3%) of the 15 patients improved in the postoperative period. Low local cerebral blood flow in the ischemic area without infarction manifested a constant and significant increase postoperatively. In summary, the stable xenon computed tomography-cerebral blood flow technique is thought to be a simple and useful method for assessing local cerebral blood flow in posterior circulation perioperatively.

Pseudoaneurysm complicating superficial temporal artery-superior cerebellar artery bypass

A 60-year-old man with vertebrobasilar ischemia unrelieved by anticoagulation was found to have a midbasilar stenosis with an inadequate basilar collateral circulation. He underwent a right superficial temporal-superior cerebellar artery bypass. Following this operation he had a subarachnoid hemorrhage and right third nerve palsy that was due to formation of a pseudoaneurysm at the site of the anastomosis. This aneurysm was managed by ligation of the right superficial temporal artery. Subsequently it became necessary to perform a left superficial temporal artery-superior cerebellar artery bypass because of severe posterior circulation ischemic symptoms.

Basilar artery occlusion after superficial temporal artery-superior cerebellar artery anastomosis

Superficial temporal artery-superior cerebellar artery anastomosis for basilar artery stenosis was performed in a patient who had experienced recurrent nonhemispheric symptoms, and whose angiogram revealed a midbasilar stenosis. Four months after the operation he was readmitted to our hospital complaining of transient motor weakness and numbness of the left extremities. No neurological deficit was found on admission, but 1 hour later the left-sided hemiparesis occurred again and progressed. On the angiograms the upper basilar system was visualized via the superficial temporal artery, and the midbasilar artery was occluded. This conversion seemed to be a natural course rather than the influence of the hemodynamic change after the operation.