Microvascular anatomy of the uncus and the parahippocampal gyrus.

The microanatomical examination of the uncal and the parahippocampal arteries was performed in 17 brain hemispheres injected with India ink and gelatin. The mentioned arteries may originate from the anterior choroidal artery, the internal carotid artery, the middle cerebral artery, and the posterior cerebral artery. The uncal or the unco-parahippocampal branches of the anterior choroidal artery were divided into rostral and caudal; the former were present in 70.6%, and the latter were present in 94.1%. The uncal or the unco-parahippocampal branches of the internal carotid artery, which originated 1.4 to 4.2 mm from its bifurcation site, existed in 58.8%. The same branches of the middle cerebral artery, which most often arose from the temporopolar artery, were present in 64.7%. Finally, these branches of the posterior cerebral artery, which usually arose from the anterior hippocampal artery, were observed in 47.1%. Large parahippocampal branches of the anterior choroidal artery were noted in 52.9%. The internal carotid artery and middle cerebral artery gave rise to these branches in 23.5 and 64.7%, respectively. The posterior cerebral artery always gave off 2 to 10 parahippocampal vessels. The largest of them originated within the rostral hippocampo-parahippocampal arterial complex. The authors discuss the microanatomical characteristics and possible clinical significance of the uncal and the parahippocampal arteries.     

Micro-anatomy of collateral perforating branches of the middle cerebral artery

The lenticulostriate arteries are the subject of a microanatomical study on 50 formalin fixed human brains. A single trunk arising from the middle cerebral artery is rarely found. In fact the branches are numerous and they are found to ramify before penetrating the anterior perforated substance. The length of the sphenoidal segment is variable and this aspect is discussed in the light of the literature data. The origin of the perforating branches is spread from the internal carotid artery to the bifurcation branches of the middle cerebral artery (M2 segment). On the other hand lenticulostriate arteries arising from the cortical branches of the middle cerebral artery are often found. These anatomical patterns are of essentially surgical interest. No branches must be damaged during the opening of the Sylvian fissure or during the dissection of an aneurysm in this region.     

The middle cerebral artery system in fetuses: the distribution of the pial branches

The aim of our study is to point out the influence of the cerebral development on the evolution of the middle cerebral artery (MCA) system. Brains of 20 fresh fetuses (16-22 weeks) were injected with gelatin-ink China mixture, observed and dissected under surgical microscope in correlation with the evolution of the sylvian fossa. Ending pattern of MCA and territories of distribution of its branches were also discussed.     

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.     

Microsurgical anatomy of the distal anterior cerebral artery

The microsurgical anatomy of the distal anterior cerebral artery (ACA) has been defined in 50 cerebral hemispheres. The distal ACA, the portion beginning at the anterior communicating artery (ACoA), was divided into four segments (A2 through A5) according to Fischer. The distal ACA gave origin to central and cerebral branches. The central branches passed to the optic chiasm, suprachiasmatic area, and anterior forebrain below the corpus callosum. The cerebral branches were divided into cortical, subcortical, and callosal branches. The most frequent site of origin of the cortical branches was as follows: orbitofrontal and frontopolar arteries, A2; the anterior and middle internal frontal and callosomarginal arteries, A3; the paracentral artery, A4; and the superior and inferior parietal arteries, A5. The posterior internal frontal artery arose with approximately equal frequency from A3 and A4 and callosomarginal artery. All the cortical branches arose more frequently from the pericallosal than the callosomarginal artery. Of the major cortical branches, the internal frontal and paracentral arteries arose most frequently from the callosomarginal artery. The distal ACA of one hemisphere sent branches to the contralateral hemisphere in 64% of brains. The anterior portions of the hemisphere between the 5-cm and 15-cm points on the circumferential line showed the most promise of revealing a recipient artery of sufficient size for an extracranial-intracranial artery anastomosis. The distal ACA was the principal artery supplying the corpus callosum. The recurrent artery, which arose from the A2 segment in 78% of hemispheres, sent branches into the subcortical area around the anterior limb of the internal capsule.     

Selective occlusion of blood supply to the anterior perforated substance of the dog: a highly reproducible stroke model

We created a highly reproducible stroke model in dogs by the selective occlusion of middle and anterior cerebral artery branches that penetrate the anterior perforated substance and supply much of the basal forebrain. We also analyzed the anatomic organization of the arterial supply to this region in this animal. Perforators came from anterior communicating artery branches similar to the recurrent artery of Heubner in humans and from the middle cerebral artery at several sites distal to the bifurcation of the internal carotid artery. Although some animals had a single source of the perforating arteries, most had two or more. In 50% of our specimens, the anterior communicating artery was the dominant source of arterial supply, in 21% the middle cerebral artery was dominant, and in 24% neither source dominated. Occlusion of all microscopically visible perforators to the anterior perforated substance reliably resulted in infarction of the internal capsule (100%), caudate nucleus (91%-100%), putamen or globus pallidus (82%-91%), and anterior commissure (73%). Structures involved less frequently in infarctions include the external capsule, claustrum, anterior commissure, and septal nuclei. We believe this anatomic information is useful for understanding why previous focal ischemia lesions in the distribution of the middle cerebral artery in the dog have been highly variable as well as for planning and interpreting future studies in this species. The proposed model of focal ischemia may be of use for the study of stroke.     

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.     

Superficial Temporal Artery to Middle Cerebral Artery Bypass

The superficial temporal artery to middle artery bypass is a technique that allows the blood supply from the extracranial carotid circulation to be routed to the distal middle cerebral artery branches. The procedure allows blood flow to bypass proximal lesions of the intracranial vasculature. The performance of this bypass requires specialized microvascular training and the use of microvascular techniques. The techniques involved in performing these procedures include microdissection of the superficial temporal artery in the scalp, microdissection of the recipient middle cerebral artery branches near the sylvian fissure, and anastomosis techniques using either microvascular sutures or a microanastomotic device. The successful completion of the bypass and subsequent patency requires meticulous attention to technical details.     

Microanatomy of the anterior cerebral artery

The microanatomic features of the anterior cerebral artery were studied in 30 unfixed human brains which were injected with tinted polyester resin via cannulation of the internal carotid arteries under microscopic dissection. The outer diameter, length, and number of perforating branches were measured for each of the following vessels: anterior cerebral artery (proximal A1 segment, distal A2 segment), anterior communicating artery, and recurrent artery of Heubner. The perforating branches of the proximal segment of the anterior cerebral artery penetrated the brain at the anterior perforated substance, lateral chiasm, and optic tracts. The perforating branches of the anterior communicating artery penetrated the brain at the lamina terminalis, anterior perforated substance, and medial chiasm. The first 5 mm of the distal anterior cerebral artery (A2) had perforating branches penetrating the brain at the gyrus rectus and olfactory sulcus. The recurrent artery of Heubner originated from the A2 segment of the anterior cerebral artery in 57% of the cases, from the anterior cerebral artery-anterior communicating artery junction in 35%, and from the A1 segment in 8%. The depth of the interhemispheric fissure at the genu was 36.0 +/- 0.5 mm and at the midbody of the corpus callosum, 35.0 +/- 0.5 mm. Extension of the dissection to approach the anterior communicating artery from the genu of the corpus callosum using the anterior interhemispheric route was an additional 31.7 +/- 0.7 mm. The callosal arterial supply from the anterior cerebral artery showed short callosal branches in all brain specimens and long callosal vessels in 10% of the specimens.     

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.     

Dural-cortical anastomosis in pial arteriovenous malformation. Case report.

A patient is reported with a purely pial arteriovenous malformation (AVM) supplied from the posterior parietal artery. The prominent middle meningeal artery contributed to opacification of the angular branches distal to the AVM, but did not contribute to the AVM. After total removal of the AVM, the angular branches became opacified from the middle cerebral artery. Review of the literature suggests that hypertrophied dural arteries which do not contribute to the AVM's but which do opacify the cortical branches distal to the AVM's are rare.     

A case of multiple anomalies of cerebral vessels--fenestration of the middle cerebral artery aneurysm of the anterior communicating artery and arteriovenous malformation on the frontopolar region (author's transl)

A case associated with multiple cerebral vascular anomalies, which consisted of fenestration of the middle cerebral artery, arteriovenous malformation and aneurysm of the anterior communicating artery, was reported. A 48 year-old male has been suffering from the left paralysis and mental disorder after the initial attack of subarachnoid hemorrhage, and the second attack resulted in the deterioration of the symptoms. He was admitted to our clinic on October 28, 1974. On neurological examination, mental disorders, such as disorientation, emotional incontinence, amnesia and acalculia, hemiplegia on the left and meningeal irritation signs were observed in admission period. Physical examination was negative. Cerebral angiographic findings were as follows: 1) Moderate vasospasm of the right internal carotid artery at the terminal segment, mild bowing of the anterior cerebral artery and stretching of the frontparietal opercular branches of the middle cerebral artery were observed. 2) Right frontpolar arteriovenous malformation fed by the frontobasal artery and the frontopolar artery, and drained via the aberrant cortical vein into the superior sagittal sinus. 3) Aneurysm of the anterior communicating artery was opacified by left carotid angiography. 4) An abnormal vessel derived from the terminal segment of the right internal carotid artery and terminated at the portion of the sphenoidal segment of the middle cerebral artery. Complete loop was formed between genuine middle cerebral artery and this abnormal artery. He was operated with dissecting microscope on November 11, 1974. The arteriovenous malformation at right frontopolar region was totally removed and aneurysm of the anterior communicating artery was clipped. According to the operative findings, the arachnoid membrane over the right frontopolar region was turbid and adhered to the adjacent tissues. On the contrary, no abnormal findings suggestive of previous subarachnoid hemorrhage were observed around the region of the anterior communicating artery aneurysm. These findings showed that subarachnoidal bleeding was caused by rupture of the arteriovenous malformation of right frontopolar region, but not by the aneurysm on the anterior communicating artery. The postoperative course was uneventful and during the hospitalization the patient starts on rehabilitation therapy. The authors discussed the genesis of fenestration of the middle cerebral artery and relation among these combined vascular anomalies. We inferred that fenestration of the middle cerebral artery arose from the in complete fusion of procursor vascular network in embryonic stage. Additionally, we emphasized that it was necessary to make a distinction between these two terms "fenestration" and "duplication".     

Inflammatory aortic arch aneurysm with total occlusion of cervical branches.

We surgically replaced the aortic root and the complex arch in a patient with aortitis syndrome with total occlusion of the cervical branches. Cerebral perfusion was being maintained through the reversed flow of the vertebral artery from the bilateral mammary arteries. Though cerebral perfusion was continued through the prosthetic grafts attached to the subclavian arteries during the procedure, bilateral watershed cerebral infarction corresponding to the most distal part of the anterior- and middle cerebral arterial system developed. With regard to the near infrared spectroscopy as a brain monitoring method, we sought to discuss the limitations.     

“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.     

Microsurgical anatomy of the insula and the sylvian fissure

OBJECT: The purpose of this study was to define the topographic anatomy, arterial supply, and venous drainage of the insula and sylvian fissure. METHODS: The neural, arterial, and venous anatomy of the insula and sylvian fissure were examined in 43 cerebral hemispheres. CONCLUSIONS: The majority of gyri and sulci of the frontoparietal and temporal opercula had a constant relationship to the insular gyri and sulci and provided landmarks for approaching different parts of the insula. The most lateral lenticulostriate artery, an important landmark in insular surgery, arose 14.6 mm from the apex of the insula and penetrated the anterior perforated substance 15.3 mm medial to the limen insulae. The superior trunk of the middle cerebral artery (MCA) and its branches supplied the anterior, middle, and posterior short gyri; the anterior limiting sulcus; the short sulci; and the insular apex. The inferior trunk supplied the posterior long gyrus, inferior limiting sulcus, and limen area in most hemispheres. Both of these trunks frequently contributed to the supply of the central insular sulcus and the anterior long gyrus. The areas of insular supply of the superior and inferior trunks did not overlap. The most constant insular area of supply by the cortical MCA branches was from the prefrontal and precentral arteries that supplied the anterior and middle short gyri, respectively. The largest insular perforating arteries usually arose from the central and angular arteries and most commonly entered the posterior half of the central insular sulcus and posterior long gyrus. Insular veins drained predominantly to the deep middle cerebral vein, although frequent connections to the superficial venous system were found. Of all the insular veins, the precentral insular vein was the one that most commonly connected to the superficial sylvian vein.     

Multiple intracranial mycotic aneurysm. Report of a case (author's transl)]

A case of intracranial mycotic aneurysm was reported, in whom repeated cerebral angiographies demonstrated the seccessive appearance of multiple aneurysms in a short term after the septic cerebral infection, and the importance of repeated angiography in the treatment of the intracranial mycotic aneurysm was stressed. A 44-year old male who had heart failure developed suddenly a left hemiparesis with irritable meningial signs on Nov. 3, 1973. The right carotid angiography carried out on Nov. 16 in an admitted hospital showed partial obliteration of cortical branches of the middle cerebral shift of the anterior cerebral artery due to the cerebral infarction. No aneurysm was demonstrated in the angiogram. The second angiography of the right carotid and vertebral artery was done on the admission of Dec. 18. The previously shown contralateral shift of the anterior cerebral artery was remarkably decreased, and an aneurysm of 3 mm in diameter was recognized at the cortical branch of the right middle cerebral artery on the parietal region. Any aneurysm was not revealed by the vertebral angiography. The third angiography of bilateral carotid and vertebral artery was performed on Dec. 25. The previously revealed aneurysm increased in size. Multiple aneurysms was demonstrated at the anterior branches of the insular artery. The vertebral angiography demonstrated multiple aneurysms at the peripheral portion of the bilateral posterior cerebral arteries. The patient was improved neurologically after the administration of antibiotics, and was discharged on Dec. 27 on the convenience of his family and would be followed in conservative cares.     

Intracranial aneurysms in early childhood

A case of an aneurysm of the middle cerebral artery in a 17-month-old child has been presented and the literature on the problem reviewed. A total of 27 aneurysms in young children (under two years of age) has been found. The characteristics that define this group of patients are: a greater proportion of aneurysms of the middle cerebral artery and its branches and of the vertebrobasilar system; greater size of the aneurysms; and frequent pseudotumor syndromes. The surgical prognosis in this group of patients is excellent. The physical and pathophysiological characteristics of these aneurysms appearing in early childhood are described.     

Focal brain ischemia model in rats. An experimental study

Using 74 male rats, anatomical variations of branching of the proximal segment of the middle cerebral artery were studied. In 36 rats (28 Sprague-Dawley rats and eight spontaneously hypertensive rats), the middle cerebral artery and/or its branches were occluded at various sites. Occlusion of the middle cerebral artery at the lateral border of the olfactory tract with or without simultaneous ligation of the ipsilateral common carotid artery rarely caused cerebral infarction in Sprague-Dawley rats. Occlusion of the olfactory branch in addition to the trunk of the middle cerebral artery caused large infarction of the pallium in five of eight Sprague-Dawley rats. Occlusion of the middle cerebral artery at the medial border of the olfactory tract caused infarction in the pallium and/or basal ganglia in five of six rats, and neurologic deficits were severe and persistent. Occlusion of the middle cerebral artery at the lateral border of the olfactory tract in spontaneously hypertensive rats caused large infarction with severe neurologic deficits in all eight animals. Possible factors responsible for such diverse differences and the relative value of each group as an experimental model of focal cerebral ischemia in rats were discussed.     

Surgical treatment of the middle cerebral artery aneurysm--from the experiences of 174 cases (author's transl)]

174 cases of middle cerebral artery aneurysm submitted to surgical operations without using microscope were reviewed. At operation, the head is set on the neutral and slightly chin up position, not turned to any directions. Small craniotomy, which is about half as much as the ordinary unifrontal craniotomy, is performed. The merit of our method is as follows; the M1 portion (Fisher) of the middle cerebral artery runs horizontally, so that we can keep the parent artery during the operation, and owing to the chin up position the strong retraction of the frontal lobe can be avoided. Of 174 cases, 9 were dead (mortality rate 5.2%) and 18 were poor (10.4%). Bad operative outcome is due to the obstruction of the middle cerebral artery around the aneurysmal neck. Therefore, we should always keep in mind to preserve the blood flow of the parent artery as well as that of its branches. Study was made mainly on this point of view such as the general technical process of the aneurysmal neck treatment, the treatment of the cases with severe arteriosclerosis and with large aneurysms having the blood coagula inside.     

大脑中动脉巨大型动脉瘤的手术治疗

目的 探讨大脑中动脉巨大型动脉瘤的手术治疗方法.方法 回顾性分析2001年1月至2008年3月17例颅内大脑中动脉巨大型动脉瘤患者的手术方法和疗效.术前采用CT、CTA、MR、MRA、DSA及三维DSA检查,以了解动脉瘤的部位、大小,形状以及侧支代偿情况,制定个体化治疗方案.在手术入路上多采用改良翼点入路,其中行动脉瘤瘤颈直接或塑形夹闭者4例,动脉瘤孤立或孤立后切除4例,动脉瘤切除或孤立后血管重建7例,动脉瘤包裹2例.结果 CT和MRI能清楚地显示动脉瘤的形状、大小.DSA及三维DSA能显示瘤颈以及与附近血管和骨质的关系.根据格拉斯骨预后评分表评分,出院时恢复优良者12例,中度病残4例,重度病残1例,无死亡病例.结论 术前有必要进行详细的影像学检查,有助于术者规划手术方法,制定个体化治疗方案,采用不同术式取得良好预后.载瘤动脉暂时性阻断、动脉瘤切开血栓清除均有助于瘤颈夹闭.血管重建技术为大脑中动脉巨大型动脉瘤的手术治疗开辟了新途径,明显改善了手术效果.