A case of spontaneous fusiform aneurysm in a middle cerebral artery branch which causes rapidly thrombosed formation in a short period

A 61-year-old man presented with the complaint of headache. Investigations revealed a fusiform middle cerebral artery aneurysm at the M2 part. The formation of the aneurysm rapidly developed to a partially thrombosed aneurysm in the course of four months. As regards the treatment of the aneurysm, at first we tried surgery with a superficial temporal artery middle cerebral artery bypass (STA-MCA bypass) and trapping of the aneurysm. However, during the procedure, it was difficult to control bleeding from the temporal muscle, bone flap, and subdural space. Because of this, we finished the STA-MCA bypass without trapping of the aneurysm and then, four days later, we confirmed bypass patency and treated the aneurysm using endovascular coil embolization. Based on both surgical and interventional investigations in this case and a review of the reported literature, the authors propose that there are two mechanisms causing the middle cerebral artery fusiform aneurysm to develop thrombosed formation rapidly: (i) Peripheral middle cerebral artery branches demand less blood flow than other major trunk arteries. (ii) Bypass flow maintains perfusion to the distal branches. On the other hand, this flow alteration caused by surgical vascular bypass may promote the development of the aneurysm to thrombosed formation. The treatment of a fusiform middle cerebral artery aneurysm at the M2 part is also discussed.     

“Reverse” superficial temporal artery-middle cerebral artery bypass

A new technical variant on the superficial temporal artery-middle cerebral artery anastomosis was performed in a patient with occlusions of both the left internal and external carotid arteries and persistent ischemic symptomatology. Instead of anastomosing the proximal segment of the superficial temporal artery to the middle cerebral artery as is conventionally done, the distal segment of the superficial temporal artery was anastomosed to a cortical branch of the left middle cerebral artery. Reconstituted flow of the left superficial temporal artery via right superficial temporal artey collateral branches proved adequate to relieve the patient's ischemic episodes. “Reverse” superficial temporal artery-middle cerebral artery anastomosis should be considered in those cases where occlusive disease of the external carotid circulation renders conventional bypass procedures ineffective in the treatment of ischemic symptomatology.     

Changes in Computed Tomography Perfusion Parameters after Superficial Temporal Artery to Middle Cerebral Artery Bypass: An Analysis of 29 Cases

Introduction Analysis of computed tomography perfusion (CTP) studies before and after superficial temporal artery to middle cerebral artery (STA-MCA) bypass is warranted to better understand cerebral steno-occlusive pathology. Methods Retrospective review was performed of STA-MCA bypass patients with steno-occlusive disease with CTP before and after surgery. CTP parameters were evaluated for change after STA-MCA bypass. Results A total of 29 hemispheres were bypassed in 23 patients. After STA-MCA bypass, mean transit time (MTT) and time to peak (TTP) improved. When analyzed as a ratio to the contralateral hemisphere, MTT, TTP, and cerebral blood flow (CBF) improved. There was no effect of gender, double vessel versus single vessel bypass, or time until postoperative CTP study to changes in CTP parameters after bypass. Conclusions Blood flow augmentation after STA-MCA bypass may best be assessed by CTP using baseline MTT or TTP and ratios of MTT, TTP, or CBF to the contralateral hemisphere. The failure of cerebrovascular reserve to improve after cerebral bypass may indicate irreversible loss of autoregulation with chronic cerebral vasodilation or the inability of CTP to detect these improvements.     

上颌动脉-大脑中动脉血管搭桥的解剖学研究

【摘要】〓目的〓探讨上颌动脉与大脑中动脉第二段近端之间进行血管搭桥的可行性。方法 解剖观察10具尸头标本(20侧)的颞浅动脉、上颌动脉及颞深动脉、大脑中动脉分叉部、颈总动脉分叉部及颈外、颈内动脉起始部,分别测量其外径,颈外、颈内动脉起始部及上颌动脉至大脑中动脉分叉部移植血管的走行距离。多普勒超声检查10例健康成人(20侧)的上颌动脉、颈总、颈外、颈内动脉及颞浅动脉主干、额支、顶支的内径和相关血流动力学参数。 结果〓尸头解剖上颌动脉外径为(2.60±0.20) mm,大于颞浅动脉分叉部外径(1.70±0.30) mm,两者差异具有统计学意义(P<0.05);上颌动脉至大脑中动脉分叉部移植血管的行程为(61.70±1.50) mm,而颈外、颈内动脉至大脑中动脉分叉部移植血管的行程分别为(162.40±2.60) mm、(171.00±2.70) mm。超声多普勒检查上颌动脉第二段血流量为(62.70±13.30) mL/min,而颞浅动脉额支、顶支血流量仅(15.90±3.70) mL/min、(17.70±4.10) mL/min,均具有统计学差异(P<0.05)。结论〓上颌动脉与大脑中动脉第二段近端进行血管搭桥是切实可行的,具有血流量大、移植血管短、路径直等优点,是一种有效的颅内外血管搭桥方法。     

Anatomic pathways facilitating middle cerebral artery bypass

Occlusion of the middle cerebral artery by thrombi is a relatively common occurrence resulting in stroke. Prompt intervention by dissolution or bypassing the thrombi could reduce the severity of the effects. Here, the anatomic pathways facilitating a bypass are explored. Four possible arteries, the two superficial temporals, left and right, and two middle meningeals, left and right, are in positions adjacent to branches of the middle cerebral arteries, the trunks of which are located in the lateral fissures of the brain. The first possibility is anastomosing a branch of the superficial temporal artery with the middle cerebral artery segment in the lateral fissure where this segment is usually clear of thrombi. The second possibility is anastomosing a branch of the middle meningeal artery with the postthrombotic segment of the middle cerebral artery. These anastomoses are to be done with donor and recipient arteries of the same side. In the unlikely event that these two possibilities are lost, it is still possible to anastomose the affected middle cerebral artery with the superficial temporal or middle meningeal artery of the opposite side using several inches of saphenous vein.     

Reversal of aphasia with superficial temporal artery to middle cerebral artery anastomosis.

Two patients with aphasia which markedly regressed following superficial temporal to middle cerebral artery anastomoses are reported. Added to the armamentarium of stroke therapy for the amelioration of focal ischemic disease, modern microvascular techniques allow the establishment of collaterals to recipient vessels of less than 1 mm in diameter. A neurological deficit which is supposed to be permanent is usually considered a contraindication to these procedures. This report details two cases in which aphasia and motor weakness markedly improved following a superficial temporal artery to middle cerebral artery anastomosis.     

Superficial temporal artery to middle cerebral artery bypass

The superficial temporal artery to middle cerebral artery bypass is an elegant procedure that was developed and first performed by M. Gazi Ya?argil. It has been used by neurosurgeons for more than 30 years in the management of neurovascular disorders such as cerebrovascular ischemic disease, moyamoya disease, and complex intracranial aneurysms. Mastering the technique requires not only precise and fine skills but also devoted training in the microsurgery laboratory. The technique presented in this article evolved from the long and vast experience of the senior author (DWN) in performing superficial temporal artery to middle cerebral artery bypasses for a variety of cerebrovascular conditions.     

Extracranial-intracranial arterial bypass in the management of symptomatic vasospasm

Delayed neurologic deterioration from vasospasm remains the greatest cause of morbidity and mortality following subarachnoid hemorrhage. The authors performed superficial temporal artery-middle cerebral artery bypass in three patients with symptomatic vasospasm and studied its effects on cerebral hemodynamics. All three patients responded neurologically to the bypass procedure within 24 hours. The average cerebral blood flow in the region supplied by the spastic middle cerebral artery increased from 40 ml/100 g/min to 49 ml/100 g/min after bypass. Angiography disclosed dilatation of donor vessels during the peak of spasm, followed by their decrease in caliber coincident with alleviation of vasospasm. The authors conclude that superficial temporal artery-middle cerebral artery anastomosis for the management of symptomatic vasospasm can increase blood flow in the ischemic region supplied by the spastic artery. This management strategy may lower the incidence of death and disability from vasospasm after subarachnoid hemorrhage.     

Radiologic evaluation of extracranial to Sylvian middle cerebral artery bypass

At this institution a new procedure has been developed that involves anastomosing one of the branches of the superficial temporal artery to one of the major trunks of the middle cerebral artery in the Sylvian fissure. This procedure has been performed in 22 cases to date. Clinical indications for this procedure have fallen into four major categories. This new type of anastomosis produces greater bypass flow than conventional cortical middle cerebral artery anastomoses, and may be a better therapeutic alternative in certain clinical situations. The preoperative and postoperative angiographic evaluation of these patients is discussed. The radiologic results in this series of patients are reviewed.     

Microsurgical neurovascular anastomosis: The example of superficial temporal artery to middle cerebral artery bypass. Technical principles

The superficial temporal artery to the middle cerebral artery (STA-MCA) bypass is a good example of cerebrovascular anastomosis. In this article, we describe the different stages of the procedure: patient installation, superficial temporal artery harvesting, recipient artery exposure, microsurgical anastomosis, and closure of the craniotomy. When meticulously performed, with the observance of important details at each stage, this technique offers a high rate of technical success (patency > 90%) with a very low morbi-mortality (respectively 3% and 1%). Some anesthetic parameters have to be considered to insure perioperative technical and clinical success. STA-MCA bypass is a very useful technique for the management of complex or giant aneurysms where surgical treatment sometimes requires the sacrifice and revascularization of a main arterial trunk. It is also a valuable option for the treatment of chronic and symptomatic hemispheric hypoperfusion (Moyamoya disease, carotid or middle cerebral artery occlusion).     

Proximal superficial temporal artery to proximal middle cerebral artery bypass using a radial artery graft: an anatomic approach

We present the use of radial artery graft for bypass of the proximal superficial temporal artery to the proximal middle cerebral artery. Six adult cadaver sites were used bilaterally. After apterional incision, 2×2-cm minicraniectomy was performed which began 2 cm behind the zygomatic process of the frontal bone. The superficial temporal artery was transsected before exposing the zygomatico-orbital artery branch. The proximal side of the radial artery graft was anastomosed end-to-end to the proximal superficial temporal artery and the distal side end-to-side to the proximal middle cerebral artery. The mean calibers of the proximal superficial temporal artery and largest trunk of the middle cerebral artery were 2.25±0.35 mm and 2.3±0.3 mm, respectively. The average graft length was 85±5.5 mm. We conclude that such bypasses are simpler than proximal middle cerebral artery revascularization using long vein grafts. This method proves that the caliber of the proximal superficial temporal artery is more suited to providing sufficient flow than the distal superficial temporal artery, and the graft is short. Such bypasses to the middle cerebral artery may be an alternative to those from the distal superficial temporal artery or extracranial carotid artery.     

Bypass surgery for moyamoya disease: concept and essence of sugical techniques

This review describes the basic concepts of surgical revascularization for moyamoya disease, including direct and indirect bypass surgery. Direct bypass surgery can improve cerebral hemodynamics and reduce further ischemic events immediately after surgery, but may be technically challenging in some pediatric patients. Indirect bypass surgery is simple and has widely been used. However, its beneficial effects can be achieved 3 to 4 months after surgery, and surgical design is quite important to determine the extent of surgical collateral pathways. Combined bypass procedure, especially superficial temporal artery (STA) to middle cerebral artery anastomosis and indirect bypass, encephalo-duro-myo-arterio-pericranial synangiosis, is a safe and effective option to improve the short- and long-term outcome in patients with moyamoya disease. Alternative techniques are also described for specific cases with profound cerebral ischemia in the anterior cerebral artery or posterior cerebral artery territory. Special techniques to safely complete bypass surgery and avoid perioperative complications are presented, including methods to prevent delayed wound healing, to avoid facial nerve palsy after surgery, and to preserve the STA and middle meningeal artery during skin incision and craniotomy. Finally, the importance of careful management of patients is emphasized to reduce the incidence of perioperative complications, including ischemic stroke and hyperperfusion syndrome.     

Observations on moyamoya disease: a case treated with superficial temporal-middle cerebral artery anastomosis

A 24-year-old Caucasian woman with Moyamoya disease was treated by a superficial temporal, middle cerebral artery anastomosis. Her pre and postoperative angiograms revealed that the telangiectatic network in the region of the basal ganglion served as a transcerebral collateral circulation from the internal carotid artery proximal to its occlusion to the cortical branches of the middle cerebral artery. The transit through two capillary systems (basal ganglia and cortical) explains the slow circulation time. Prompt venous drainage was seen to occur once a more direct collateral supply was established by the superficial temporal-middle cerebral artery anastomosis.     

Cerebral revascularization: a review

A review of the development and current methods of surgical revascularization of the cerebral circulation is presented. In addition to the conventional superficial temporal artery to middle cerebral artery (STA-MCA) bypass, the techniques of interposition vein grafting and vertebrobasilar revascularization are discussed. The results and implications of the International Cooperative Study are reviewed. Extracranial-intracranial (EC-IC) bypass grafting remains an essential procedure in the treatment of many cerebrovascular conditions, including Moya Moya disease and giant intracranial aneurysms. The efficacy of interposition vein grafts, as well as the EC-IC bypass in the treatment of vertebrobasilar insufficiency, acute cerebral ischemia, cerebral vasospasm, and multi-infarct dementia, remains to be determined. Several alternative revascularization procedures, including proximal MCA anastomosis and omental transposition, are in development.     

Direct surgical treatment of giant middle cerebral artery aneurysms using microvascular reconstruction techniques

Giant intracranial aneurysm is a life-threatening lesion and treatment of the aneurysm could be hazardous and complex. This study describes direct surgical treatment of giant middle cerebral artery (MCA) aneurysms using microvascular reconstruction techniques in 13 patients treated between 2006 and 2009. In all 13 patients, superficial temporal artery (STA)-MCA (M(2)) anastomosis was performed as a precaution prior to attacking the aneurysm. During surgery, microvascular reconstruction of incorporative arteries was additionally performed if the aneurysm was removed. Direct neck clipping was performed in four patients, trapping and removal of the aneurysm in one, and removal of the aneurysm with vascular reconstruction of the MCA in eight patients. Minor ischemic complications due to perforator ischemia were recognized in 6 patients, and 10 patients achieved functionally favorable outcomes (modified Rankin scale score 0 or 1). In direct surgery for giant MCA aneurysm, precautionary STA-M(2) bypass could provide appropriate surgical strategies tailored to individual cases, including direct clipping and removal of the aneurysm with or without vascular reconstruction. Microvascular reconstruction techniques are essential for complete cure of giant MCA aneurysms.     

Effects of hypercapnia on cerebral blood flow following prophylactic and delayed experimental superficial temporal artery-middle cerebral artery bypass

Cerebral blood flow was studied in dogs to ascertain whether preexisting superficial temporal artery-middle cerebral artery bypass could preserve hypercapnic reactivity following acute ischemia and whether postischemic-delayed revascularization would restore hypercapnic reactivity. In six dogs flow was preserved and some degree of hypercapnic response remained following proximal occlusion with a patent bypass. During complete ischemia (bypass occluded) there was no hypercapnic reactivity in the ischemic zone. Significant flow was restored to the ischemic area following bypass reopening, but a cerebral blood flow decrease was seen with subsequent hypercapnia. In the opposite (control) hemisphere hypercapnia always produced significant cerebral blood flow increases. These data support the superiority of prophylactic over delayed superficial temporal artery-middle cerebral artery bypass in appropriate clinical situations.     

Arterial patterns of the deep and superficial palmar arches

The vascular patterns of the palmar arches and their interconnecting branches present a complex and challenging area of study. Improvements in microsurgical techniques have made a better understanding of vascular patterns and vessel diameters more important. Forty-five fresh limbs from cadavers were amputated at the level of the midhumerus. Ward's red latex or Batson's compound was injected under pressure to visualize the arterial system in the hand. After hardening of the injected material, the skin, subcutaneous tissues, and tendons were removed. The specimens were digested in concentrated potassium or sodium hydroxide leaving the bony elements and a cast of the arterial system. The superficial palmar arch is most easily classified into two categories: complete or incomplete. An arch is considered to be complete if an anastomosis is found between the vessels constituting it. An incomplete arch has an absence of a communication or anastomosis between the vessels constituting the arch. Complete superficial palmar arches were seen in 84.4% of specimens. In the most common type, the superficial arch was formed by anastomosis between the superficial volar branch of the radial artery and the ulnar artery. This was seen in 35.5% of specimens. In 31.1%, the arch was formed entirely of the ulnar artery. Incomplete superficial arches were seen in 15.5% of specimens. In 11.1%, the ulnar artery forms the superficial arch but does not contribute to the blood supply to the thumb and index finger. The deep palmar arch was found to be less variable with 44.4% formed by an anastomosis between the deep volar branch of the radial artery and the inferior deep branch of the ulnar artery. Injection followed by chemical debridement allows direct visualization and measurement of the arches and the smaller arterial branches that are visualized poorly with other techniques. Based on the vessel measured, vessels of the superficial and deep arches are of sufficient size to allow microvascular repair, although repair of the communicating branches, the dorsal carpal rete, and its branches, probably is not feasible because of their small size.     

STA-ACA bypass using the contralateral STA as an interposition graft for the treatment of complex ACA aneurysms: report of two cases and a review of the literature

Bypass surgery has been used as a remedy for the complex cerebral aneurysm, which was unsolved with the clipping method. However, little has been reported about bypass options for anterior cerebral artery (ACA) aneurysms. The authors experienced two patients with complex ACA aneurysms, large fusiform and large thrombosed aneurysms involving the distal A1 and proximal A2 segments, respectively. To achieve complete obliteration of the aneurysm, we performed a superficial temporal artery (STA)-ACA bypass using contralateral STA as interposition grafts with endovascular trapping without any ischemic events. These cases show that STA-ACA bypass using contralateral STA interposition graft is a feasible option to maintain blood supply to the ACA territory if a proximal ACA lesion requires trapping.     

Reflow into a thrombosed giant middle cerebral artery aneurysm after extracranial-intracranial bypass

This report graphically illustrates the consequences of flow augmentation through extracranial-intracranial bypass grafts. Propagation of clot from a thrombosed middle cerebral artery aneurysm into the middle cerebral artery produced transient ischemic attacks. Superficial temporal artery-middle cerebral artery bypass was performed to augment cerebral blood flow. Postoperative angiography demonstrated filling of the aneurysm through improved collateral channels. The role of bypass operation in the presence of an aneurysm and its contribution to collateral blood flow and clot lysis are discussed.