Cerebrovascular Bypass Research Articles

Surgical Strategies for Fusiform A2 and Giant Anterior Communicating Artery Aneurysms

usiform aneurysms (FAs) are circumferential lesions of an entire vessel segment and are difficult to treat, espeF cially compared with their saccular counterparts. Although saccular aneurysms are generally accepted as treatable by direct clipping or coil embolization, there is ongoing debate about which therapy is best suited for FAs. Depending on aneurysm location and specific preference of the treating neurovascular center, FAs are usually treated by endovascular stent placement (with growing emphasis on flow diverters), proximal occlusion alone (endovascular or surgical), or cerebrovascular bypass surgery in combination with proximal or distal aneurysm occlusion (1, 2).

Cerebrovascular bypass and aneurysm trapping for the treatment of an A2-segment anterior cerebral artery pseudoaneurysm and herniation through a skull base defect following trauma

Fractures of the anterior skull base can lead to pseudoaneurysm formation as a result of direct injury to a vessel wall. Pseudoaneurysms in this location are challenging to treat, as both perforator and distal blood supply must be maintained. Additionally, traumatic skull base fractures can lead to a rare condition of cerebral blood vessel herniation through the bony defect, further complicating treatment planning. Treatment of these lesions is essential to (1) prevent the occurrence of potentially fatal subarachnoid hemorrhage and (2) prevent dissection from propagating and compromising blood flow to distal vessels, perforators, and even parent vessels. We present a unique case of a traumatic proximal anterior cerebral artery pseudoaneurysm, herniating through a skull base defect. Treatment consisted of aneurysm trapping and bypass with skull base reconstruction.

Surgical Treatment of a Large Fusiform Distal Anterior Cerebral Artery Aneurysm With In Situ End-to-Side A3—A3 Bypass Graft and Aneurysm Trapping: Case Report and Review of the Literature

Large fusiform aneurysms of the distal anterior cerebral territory are extremely rare and can be particularly challenging to treat. The circumferential pathology of fusiform lesions renders stand-alone clip or coil ablation unsatisfactory, and the deep, narrow corridor augments the difficulty of surgical approaches. In this setting, bypass procedures may be used to both treat the aneurysm definitively and preserve distal parent artery flow. We report a rare case of a large fusiform A3 aneurysm treated with trapping and concomitant end-to-side A3:A3 bypass. A 52-year-old man was evaluated after losing consciousness and experiencing a fall. A noncontrast computed tomography scan revealed a focal area of hemorrhage above the body of the corpus callosum, and computed tomography angiography showed a fusiform aneurysm of the right A3 artery. To treat the aneurysm definitively and preserve distal vessel flow, the patient was taken to surgery in anticipation of aneurysm ablation and cerebrovascular bypass. A large, fusiform right A3 aneurysm was identified. Intraoperative flow measurement demonstrated poor collateral circulation. The aneurysm was trapped with clips, and a right-to-left A3:A3 end-to-side in situ bypass was performed. Aneurysm occlusion and preserved distal vessel flow were confirmed with intraoperative angiography. Large fusiform aneurysms in the distal anterior cerebral artery region are rare, and the anatomy of these lesions and their vascular location render stand-alone surgical management technically challenging. End-to-side A3:A3 bypass combined with aneurysm trapping represents a feasible treatment strategy for lesions in this location.

Excimer laser-assisted non-occlusive cerebral vascular Anastomosis (ELANA): Review of the first UK experience

The Excimer Laser Assisted Non-occlusive cerebral vascular Anastomosis (ELANA) has been proposed as a major advance in the field of cerebral revascularisation. Appreciable challenges remain, however. We report our experience with introducing this technique to the UK and review the field of cerebral revascularisation and flow replacement.Retrospective review of prospectively recorded case series. Data were collected prospectively, complication data were recorded and analyzed and functional surgical outcomes were measured using the modified Rankin scale (MRS). Ten patients, during a 2-year period, were considered suitable for high-flow cerebrovascular bypass surgery, with 8 proceeding to surgery. Seven bypasses were completed and 1 abandoned. Of the 5 patients neurologically intact preoperatively, 3 remained so postoperatively, 4 experienced no neurological deficit and one suffered transient hemiparesis due to hyperperfusion which resolved. One patient with preoperative hemiparesis improved. One patient died 8 days postoperatively. Overall long-term patency rate was (42%), however 3 thrombosed bypasses were all competitive (used for prophylactic intraoperative reasons), 2 thrombosing after the surgical procedure was completed. We discuss the role for this modern technique and the lessons learnt from its introduction to the UK, and consider the current and future requirements for cerebral revascularisation.

Cerebrovascular reactivity and coronary artery bypass surgery

Cerebrovascular reactivity and coronary artery bypass surgery

A case of moyamoya disease presenting with chorea

We describe a 15-year-old girl with moyamoya disease whose initial manifestation was chorea-like involuntary movements. T2-weighted magnetic resonance imaging showed high signal intensity lesions in the left frontal lobe, right parieto-occipital lobes, and frontal subcortical white matter. Single-photon emission computed tomography (SPECT) showed diffuse hypoperfusion of the whole brain. Bilateral direct and indirect cerebrovascular bypass surgeries were performed. Chorea disappeared 2 days after the surgery. Follow-up SPECT demonstrated increased cerebral perfusion in the bilateral frontal, temporal, and parietal regions. Chorea accompanied with moyamoya disease can be properly managed by revascularization surgery. Moyamoya disease should be remembered as being one of the differential diagnoses of chorea, which is treatable by surgery.

Interpositional carotid artery bypass strategies in the surgical management of aneurysms and tumors of the skull base

Cerebral revascularization is an important component in the surgical management of complex skull base tumors and aneurysms. Patients who harbor complex aneurysms that cannot be clipped directly and in whom parent vessel occlusion cannot be tolerated may require cerebrovascular bypass surgery. In cases in which skull base tumors encase the carotid artery (CA) and a resection is desired, a cerebrovascular bypass may be necessary in planned CA occlusion or sacrifice. In this review the authors discuss options for performing high-flow anterograde interposition CA bypass for lesions of the skull base. The authors review three important bypass techniques involving saphenous vein grafts: the cervical-to-petrous internal carotid artery (ICA), petrous-to-supraclinoid ICA, and cervical-to-supraclinoid ICA bypass. These revascularization techniques are important tools in the surgical treatment of complex aneurysms and tumors of the skull base and cavernous sinus.

Conduits for cerebrovascular bypass and lessons learned from the cardiovascular experience

Direct cerebral revascularization is an important procedure in the treatment of certain complex aneurysms and skull base tumors when acute sacrifice of the internal carotid artery is required. It likely remains an appropriate treatment in a small subgroup of patients with cerebral ischemia refractory to maximal medical management. Similar to cardiovascular surgery, the choice of a graft conduit is critical for a successful outcome. The standard conduits are interposition vein grafts (usually the greater saphenous vein), free arterial grafts (radial artery), and pedicled arterial grafts (superficial temporal artery). The goal of this review is to summarize the conduits commonly used in cerebral revascularization with emphasis on their patency rates and flow characteristics. Comparisons are made with similar data available in the cardiovascular literature.

Stroke in hemoglobin (SD) sickle cell disease with moyamoya: successful hydroxyurea treatment after cerebrovascular bypass surgery

AbstractAn 11-year-old boy with hemoglobin sickle disease (HbSD), bilateral stenosis of the intracranial carotid arteries, and moyamoya syndrome had recurrent ischemic strokes with aphasia and right hemiparesis. His parents (Jehovah's Witnesses) refused blood transfusions. After bilateral extracranial–intracranial (EC-IC) bypass surgery, hydroxyurea treatment increased hemoglobin F (HbF) levels to more than 30%. During a follow-up of 28 months, flow velocities in the basal cerebral arteries remained stable, neurologic sequelae regressed, and ischemic events did not recur. This is the first report of successful hydroxyurea treatment after bypass surgery for intracranial cerebral artery obstruction with moyamoya syndrome in sickle cell disease. The patient's religious background contributed to an ethically challenging therapeutic task.

Arachnoid membrane closure: Prevention of postoperative cerebrospinal fluid leakage

BACKGROUND Opening the arachnoid membrane causes leakage of the cerebrospinal fluid (CSF). CSF spillage and collection in the subdural, epidural, and/or subcutaneous space are occasionally seen on a postoperative CT scan. Closure of the arachnoid membrane is considered to be unnecessary because most of the fluid in the extracerebral space is temporary and disappears spontaneously. However, in some cases, this CSF collection results in serious complications such as brain compression, extracerebral hematoma, intractable meningitis, and skin problems. In this study for prevention of CSF leakage, the arachnoid membrane was tightly closed with 10-0 nylon after a small opening was made for cerebrovascular bypass surgery. METHODS The arachnoid membrane closure was performed in 18 patients (20 sides) after bypass surgery between 1994 and 1995. As a control, 51 patients (57 sides) had conventional bypass surgery without the arachnoid membrane closure. RESULTS The radiological findings revealed that only one (5%) of the patients had a small fluid collection after arachnoid membrane closure, which was significantly lower than the control (49%). CONCLUSION Arachnoid membrane closure is a simple technique and is effective for prevention of postoperative extracerebral CSF collection.

Angiographic study of Moyamoya disease and histological study in the external carotid artery system

A total of 13 cases of Moyamoya disease were verified by internal and external carotid artery angiography. The biopsy samples were taken from the superficial temporal arteries and middle meningeal arteries in 12 and six cases, respectively. Angiographical and histological studies revealed that both of the internal and external carotid system could be involved in Moyamoya disease. Our studies demonstrated that Moyamoya disease was a type of vascular disease not only confined to the cerebral vessels. We recommend angiography of external carotid system and extracranial segment of internal carotid artery while performing three vascular angiography. Whether superficial temporal artery has been involved in angiography can be used as an indication of indirect cerebrovascular bypass.

Cerebrovascular bypass surgery for the treatment of Moyamoya disease: Unsatisfactory outcome in the patients presenting with intracranial hemorrhage

While the efficacy of cerebrovascular bypass surgery for Moyamoya disease with ischemic events has been substantiated, the surgical indication for the patients presenting with intracranial hemorrhage is as yet undetermined. In an effort to prevent rebleeding from rupture of Moyamoya vessels, seven patients with intracranial hemorrhage underwent indirect bypass surgery. During the follow-up period between 2 and 11 years (mean 4.9 years), one patient suffered rebleeding 5 years after bypass surgery. Follow-up cerebral angiography failed to show revascularization and reduction of moyamoya vessels in all but one of seven patients. Thus, the author's experience suggests that bypass surgery for Moyamoya disease with hemorrhage is angiographically far less successful compared to that with ischemia. A review of the series including patients with angiographically successful revascularization and reduction of Moyamoya vessels failed to demonstrate the definitive effectiveness in eliminating the risk of further intracranial hemorrhage.

Steroid‐responsive chorea in moyamoya disease

We report the case of a 13-year-old boy with disabling chorea due to moyamoya disease. His chorea seemed to improve with steroid therapy. We conclude that steroid therapy may ameliorate moyamoya-associated chorea, and perioperative steroids can confound neurosurgical outcome. We are unable to assess the effect of cerebrovascular bypass procedures on the outcome of chorea in this patient.