脑供血动脉直接测压在脑动静脉畸形栓塞治疗前后的应用

对16例脑动静脉畸形（AVM）病人的34支供血动脉在用真丝线段栓塞治疗前后经微导管直接测压，结果栓塞后平均压力升高2．3kPa（P＜0．01）。认为微导管直接测压能为脑AVM血管内栓塞治疗提供准确的血液动力学参数，可以正确指导临床治疗。     

Surgical removal of radio-induced lesions after radiosurgery of cerebral arteriovenous malformations

Radioinduced lesions after radiosurgery of cerebral arteriovenous malformations may be associated with an increased signal on T2-weighted and gadolinium enhancement on T1-weighted MR images. They do not have necessarily a poor prognosis. These lesions are mostly asymptomatic. But in a few cases they can be associated with severe clinical symptoms which can become corticodependant or corticoresistant. We present the 5 cases of such cerebral arteriovenous malformations treated by radiosurgery, out of our series of 705 patients. The removal was easier than that of untreated cerebral arteriovenous malformations, and led to a complete recovery of symptoms and progressive decrease of imaging abnormalities. Such surgery should be proposed in case of symptomatic radioinduced lesions which fail to respond to steroids.     

Shear stress in cerebral arteries supplying arteriovenous malformations

Summary Arteries supplying cerebral arteriovenous malformations (AVMs) are known to dilate with time. These changes are reversible, and the feeders have been shown to slowly decrease in calibre after removal of the AMV. There is evidence that arteries alter their internal diameters in response to sustained changes of blood flow so that shear stress is kept constant. This implies that blood flow-induced shear stress might be the driving force for remodelling of the cerebral vascular network in the presence of an AVM, and for reversion of these changes after radical operation. The objective of this study is to examine the hypothesis that the shear stress in cerebral arteries supplying AMVs is of the same magnitude as in arteries supplying normal brain tissue in spite of larger blood flow rate. Fifteen patients with supratentorial cerebral AVMs admitted for endovascular treatment were examined with transcranial Doppler ultrasound in the distal Willisian vessels. Vessel calibres were measured in angiograms with magnification correction. Shear stress was estimated assuming a constant value for blood viscosity. Corresponding arteries in the cerebral hemisphere with AVM and in the contralateral one were compared in pairs. Thirty-four pairs of homonymous arteries were studied. The arteries on the AVM side presented larger calibres, higher axial blood flow velocities, lower pulsatility index and larger blood flow rates than the contralateral side. There was a clear positive correlation between blood flow velocities and vessel calibres. The estimates of shear stress did not differ significantly in corresponding arteries of both hemispheres (p = 0.18).The results indicate a precise adjustment of cerebral arterial calibre and blood flow-induced shear stress that presumably induces the progressive dilation of AVM feeders, and the slow regression of the vessel calibres to average dimensions after removal of the lesion. Each vessel seems to remodel itself in response to long-term changes in blood flow rate so that the vessel calibre is reshaped to maintain a constant level of wall shear stress.     

Microsurgical removal of arteriovenous malformations of the basal ganglia

Arteriovenous malformations in the basal ganglia region have been a problem in neurosurgical practice. We report six cases of deep-seated malformations fed mainly by the perforating branches of the middle cerebral artery. There were no deaths in the series. Four patients returned to their previous activities, and the other two patients had persistent hemiparesis and dysphasia, present preoperatively, with worsening in one case. Both of these patients improved and are independent. We show the feasibility of satisfactory microsurgical treatment of these lesions based on the knowledge of microanatomical studies.     

Pulmonary arteriovenous malformations after cavopulmonary connection

We report the case of a child with hypoplastic left heart syndrome who developed pulmonary arteriovenous (AV) malformations after superior cavopulmonary anastomoses. Resolution of the pulmonary AV malformations occurred following a completion Fontan procedure. This phenomenon has been reported previously, but only in patients with heterotaxy and polysplenia.     

Pulmonary arteriovenous malformations after cavopulmonary anastomosis

Pulmonary arteriovenous malformations (PAVMs) are a cause of progressive cyanosis after cavopulmonary anastomosis in children with single ventricle physiology who are on the pathway leading to a Fontan procedure. Investigations into possible mechanisms for the etiology of PAVMs are ongoing and suggest that the liver might play a key regulatory role in the development of these lesions.     

Interhemispheric approach for the surgical removal of thalamocaudate arteriovenous malformations

A series of 250 surgically treated cerebral arteriovenous malformations (AVM's) is presented, in which 22 lesions were located primarily in the thalamus and caudate nucleus. A standardized interhemispheric approach through the posterior corpus callosum and into the atrium of the lateral ventricle was utilized for the surgical removal of these AVM's. Total removal was confirmed by angiography in 18 patients; removal was subtotal in four cases. There were no deaths in this group of patients. Disturbances of recent memory pre- and postoperatively were seen in half of the patients, but most of these deficits were temporary. Other complications included: postoperative homonymous hemianopsia (six cases), transient hemiparesis (three cases), hemisensory loss (two cases), Parinaud's syndrome (one case), and recurrent hemorrhage 2 years after surgery (one case). All 22 patients returned to their previous occupations and are leading independent lives. The results of this experience indicate that thalamocaudate AVM's can be effectively treated by resection.     

Risk factors for neurological deficits after surgical treatment of brain arteriovenous malformations supplied by deep perforating arteries

Neurosurgical Review - The treatment of brain arteriovenous malformations supplied by deep perforating arteries (PA) (P-BAVM) remains challenging. The aims of this study were to determine the...     

Intracranial hemorrhage following attempted embolization and removal of large arteriovenous malformations

Two cases of intracranial hemorrhage following staged flow reduction procedures for large arteriovenous malformations are presented. Possible causes of bleeding in these cases are discussed. We suggest that the staged removal of large arteriovenous malformations may not prevent hemorrhagic complications in certain cases.     

Complications after multidisciplinary treatment of cerebral arteriovenous malformations

SummaryPatients and techniques A series of 67 patients treated for cerebral AVMs with a multidisciplinary approach is reported, with special attention for the complications due to treatment. The malformations were classified after the Spetzler Grading Scale, with 67% low-grade and 33% highgrade AVMs. Three modes of treatment were used: surgical resection, endovascular embolization, and radiosurgery (linear accelerator technique). The actual treatment was: resection alone (25% of cases), embolization plus resection (24%), embolization alone (21%), and radiosurgery (30%), either alone or after embolization or surgery. The following eradication rates were obtained: overall 80%, after resection (with or without embolization) 91%, after embolization alone 13%, after radiosurgery 87%.Clinical outcome The outcome was evaluated in terms of deterioration due to treatment. A deterioration after treatment occurred in 19 patients (28%), and was a minor deterioration (19%), a neurological deficit (4%), or death (4%). As far as the mode of treatment is concerned, surgical resection was responsible for deterioration (minor) in 17% of all cases operated upon. Radiosurgery was followed by a minor deterioration in 10% of irradiated cases. Embolization gave a complication in 25% of all embolized cases (minor or neurological deficit, or death). The mechanism of the complications was: resection or manipulation of an eloquent area during surgery, radionecrosis after radiosurgery, ischaemia and haemorrhage (50% each) following embolization. In most cases of haemorrhage due to embolization, occlusion of the main venous drainage could be demonstrated.Discussion The haemodynamic disturbances to AVMs and to their treatment are reviewed in the literature. The main haemodynamic mechanisms admitted at the beginning of a complication after treatment of cerebral AVMs are the normal perfusion pressure breakthrough syndrome, the disturbances of the venous drainage (venous overload or occlusive hyperaemia), and the retrograde thrombosis of the feeding arteries.Conclusions According the authors' experience, the emphasis of treatment for cerebral AVMs has now shifted from surgical resection to endovascular embolization. One of the explanations is that endovascular techniques are now employed in the most difficult cases (high grade AVMs). As severe complications of endovascular embolization may also occur for low-grade malformations, the question arises whether surgery or radiosurgery should not be used first for this low-grade group even if embolization is feasible.     

Acute surgical removal of low-grade (Spetzler-Martin I-II) bleeding arteriovenous malformations

Background

Early surgical removal of cerebral AVMs is a relatively infrequent therapeutic option when dealing with a cerebral hemorrhage caused by AVM rupture: even in the case of low-grade AVMs, delayed treatment is, if possible, preferred because it is considered safer for patients and more comfortable for surgeons. To assess whether acute surgery may be a safe and effective management, we conducted a retrospective analysis of our early surgery strategy for ruptured low-grade AVMs.

Methods

We reviewed 27 patients with SM grade I-II AVM treated during 2004 to 2008 in the acute stage of bleeding (within the first 6 days after bleed). All patients showed a cerebral AVM on DSA at admission, and surgical removal was controlled by postoperative angiography. Neurological outcomes were assessed with GOS. The average length of follow-up was 22 months (48-3 months).

Results

Before surgery, 16 (59%) patients showed a GCS of 8 or less, 2 of them presenting an acute rebleeding after first hemorrhage. All patients underwent radical AVM surgical removal and hematoma evacuation in a single-stage procedure. Most patients (78%) were operated within the first day of hemorrhage. A favorable functional outcome (GOS: good recovery or moderate disability) was observed in 23 patients (85%). Mortality was 7.4%. Outcome was not significantly correlated with GCS at presentation and with presence of preoperative anisocoria.

Conclusions

Early surgery for grade I-II AVMs is a safe and definitive treatment, achieving both immediate cerebral decompression and patient protection against rebleeding, reducing time of hospital stay and allowing a more rapid rehabilitative course whenever necessary.     

Development of pulmonary arteriovenous malformations after modified Fontan operations

Two patients with complex cyanotic congenital heart disease and without previous Glenn anastomosis underwent modified Fontan operations. Postoperatively, pulmonary arteriovenous malformations developed that resulted in cyanosis from significant intrapulmonary right-to-left shunting. These malformations were detected by pulmonary angiograms and contrast echocardiograms. Pulmonary arteriovenous malformations may be a major cause of late clinical deterioration in patients treated with modified Fontan operations.     

Intracranial arteriovenous malformations

Intracranial arteriovenous malformations (AVM) are rare lesions that are often discovered fortuitously. They should be identified on CT scan and MRI before resorting to angiography; the latter is used to prepare the treatment. This article describes the various types of subpial or dural AVM and the specific characteristics that enable their differentiation with non-invasive imaging. The factors that determine the severity of these lesions, whether discovered before or after a haemorrhage, are described, as well as prognostic indicators.