Posterior fossa arterio-venous malformations: current multimodal treatment strategies and results

The present study aimed to determine the clinical presentation, the multimodal interdisciplinary treatment strategies and outcome of posterior fossa arterio-venous malformations (AVMs) in our neurovascular centre. Fifty-three patients with a posterior fossa AVM were seen between 1998 and 2012 and analysed retrospectively. Patients were either managed conservatively or treated with endovascular, microsurgical or radiosurgical procedures or in combination. Thirty-nine patients (74 %) presented with intracranial haemorrhage and 14 patients (26 %) with unspecific symptoms. In 22 cases with haemorrhage (56 %), an intracerebellar haematoma was found, whereas 17 patients (44 %) suffered from subarachnoid haemorrhage. AVMs were located in the cerebellum in 44 patients (83 %), in the brainstem in four patients (7.5 %) and the cerebello-pontine angle in another four individuals (7.5 %). Forty-two patients (79 %) were treated either by emboliziation (n?=?12, 29 %), surgical resection (n?=?16, 38 %), surgical resection with preoperative embolization (n?=?12, 29 %) or radiotherapy alone (n?=?2, 4 %). A total of eleven patients did not receive any treatment (21 %). Both, morbidity and mortality related to treatment were 12 %, whereas overall morbidity and mortality was 26 and 15 %, respectively. Complete AVM elimination was achieved in 81 % of the treated lesions. A multimodal treatment sequence nowadays represents the gold standard for posterior fossa AVMs. Patients are at high risk for morbidity and mortality, due to the impact of haemorrhage and treatment. Therefore, treatment has to be thoroughly indicated, especially for those patients without bleeding. The initial neurological condition seems to be crucial in terms of clinical outcome.     

Interventional treatment of arterio-venous malformations

Background

Due to their hemodynamic effects and tendency to progress, the majority of congenital arterio-venous malformations (AVM) require treatment. AVM are classified according to clinical severity (Schobinger classification, stages I–V) and angiographic appearance (types I–IV).

Treatment

Endovascular embolization is the treatment of choice. However, because complications such as necrosis and neuropathy occur in up to 15% of cases, treatment is challenging and is dependent on the angiographic appearance. Critical for treatment success is elimination of the so-called nidus, which is the location of the short circuit connection between the artery and the often extended aneurysm-like drainage vein. Embolization of only the feeding artery without the actual nidus or the incomplete elimination of drainage veins should be avoided. Absolute 96?% alcohol in addition to coiling of the nidus has been established as the most effective technique.

Conclusion

Unlike other embolic agents, alcohol leads to a definitive destruction of the vessel wall. Recanalization and recurrence are excluded due to adequate elimination of the nidus.     

Management of associated primary cerebral neoplasms and vascular malformations: 2. Intracranial arterio-venous malformations

Summary 3 cases of primary cerebral tumours associated to intracranial arterio-venous malformations are reported. The presenting symptoms were caused by the AVM in 2 patients, by the tumour in 1 patient. In 2 cases the lesions were coexistent, while in one case the tumour was diagnosed 30 months after resection of the AVM. The tumour was a glioma in 2 cases, a pituitary adenoma in 1 case. The AVM was located in the right hemisphere in 2 patients, and was always ipsilateral to the tumour. Surgical treatment was undertaken in all patients, and consisted of resection of the tumour and AVM in 2 cases, and only resection of the tumour in 1 case. As regards outcome, one patient survived with a mild deficit, and 2 patients died from the natural evolution of the malignant tumour. It is concluded that the management of associated AVMs and brain tumours should be decided in the individual patient according to various considerations, owing to the variability of each lesion and to the relatively benign prognosis of an arterio-venous malformation.     

Interventional neuroradiology for the treatment of inaccessible arterio-venous malformations

Summary Embolization of cerebral arterio-venous malformations (AVM) has been performed at the Department of Neuroradiology of Verona in 136 patients with a total of 310 procedures. The complication rate was 16%. In most of the cases embolization was followed by either operative removal of the AVM or by radiosurgery.In a group of 38 embolized patients, who refused operation or radiosurgery, rebleeding occured 7 times (18%), but only in patients who already had bleedings before embolization.Indications and techniques of embolization are described and discussed.Presented at the EANS-Wintermeeting on High Risk Neurosurgery, Budapest, February 20–23, 1991.     

Spontaneous disappearance of intracranial arterio-venous malformations

Summary 4 cases of spontaneous disappearance of intracranial arteriovenous malformations are reported. All the malformations were in the rolandic-parietal area, and fed in most cases by the MCA. In one case, the malformation was associated with a proximal aneurysm. One malformation was large, one medium-sized, and two small. Venous drainage was towards the longitudinal sinus in all cases. Presenting symptoms consisted of epilepsy in 2 cases, and intracerebral haemorrhage in 2 cases. Disappearance of the AVM was documented by angiography from 1 to 15 years after diagnosis, and was preceded by a new haemorrhage in 2 cases. Acute or gradual thrombosis of the AVM is suggested as the most likely cause of the disappearance of an AVM. Spontaneous thrombosis of an AVM should be considered as an aspect of the pathological entity known as thrombosed AVM. Guidelines for the management of patients exhibiting spontaneous disppearance of an AVM are briefly discussed.     

Surgical planning for microsurgical excision of cerebral arterio-venous malformations using virtual reality technology

Background  To evaluate the feasibility of surgical planning using a virtual reality platform workstation in the treatment of cerebral arterio-venous malformations (AVMs) Methods  Patient- specific data of multiple imaging modalities were co-registered, fused and displayed as a 3D stereoscopic object on the Dextroscope, a virtual reality surgical planning platform. This system allows for manipulation of 3D data and for the user to evaluate and appreciate the angio-architecture of the nidus with regards to position and spatial relationships of critical feeders and draining veins. We evaluated the ability of the Dextroscope to influence surgical planning by providing a better understanding of the angio-architecture as well as its impact on the surgeon’s pre- and intra-operative confidence and ability to tackle these lesions. Findings  Twenty four patients were studied. The mean age was 29.65 years. Following pre-surgical planning on the Dextroscope, 23 patients underwent microsurgical resection after pre-surgical virtual reality planning, during which all had documented complete resection of the AVM. Planning on the virtual reality platform allowed for identification of critical feeders and draining vessels in all patients. The appreciation of the complex patient specific angio-architecture to establish a surgical plan was found to be invaluable in the conduct of the procedure and was found to enhance the surgeon’s confidence significantly. Conclusion  Surgical planning of resection of an AVM with a virtual reality system allowed detailed and comprehensive analysis of 3D multi-modality imaging data and, in our experience, proved very helpful in establishing a good surgical strategy, enhancing intra-operative spatial orientation and increasing surgeon’s confidence.     

Multiple intracranial cavernous malformations: clinical features and treatment

BACKGROUND: Although patients with MCMs have increasingly been found in clinics, little has been focused on them. Thus, we intended to investigate these patients' clinical presentations, family history, radiological characters, and treatment strategy. METHODS: A retrospective review of the files and family investigations were conducted for 30 patients with MCMs. All patients underwent MRI examination. Symptomatic patients underwent the surgical treatment with image-guided technique. RESULTS: There were 19 male and 11 female patients with a total 79 lesions. The common presentations were seizures, hemorrhages, or focal neurological deficits. Nine patients had positive or doubtful family history. The FLAIR sequence of MRI showed the highest sensitivity in the detection of CM lesions. In 27 symptomatic patients with 69 lesions, total removal was achieved in 19 patients with 48 lesions. In the other 8 patients with 21 lesions, 13 lesions were removed. Preoperative symptoms were improved in 21 patients and unchanged in 5. Preoperative neurological deficits temporarily worsened in one, and a new onset of seizure occurred in other one; but both gradually improved during the follow-up period. Among 3 patients with asymptomatic MCMs, one patient had hemorrhage during the follow-up period and underwent surgical operation. CONCLUSIONS: Because a high frequency of family CM occurs in MCMs, a detailed family investigation is mandatory for each patient with MCM. Selection of higher sensitive MRI sequence would contribute to detection of more CM lesions. Microsurgery assisted with the neuroimaging techniques is the treatment of choice for symptomatic MCMs.     

Cerebral arteriovenous malformations. 2. A study of cerebral hemodynamics

Regional cerebral blood flow (rCBF) in 16 patients with cerebral AVM was measured using 133-Xe inhalation cerebrograph, and in 3 patients rCBF was measured using stable xenon enhanced CT. Neurological status and angiographical findings were studied in the connection with rCBF measurement. RCBF in almost patients with hemorrhagic episodes was low in the frontal area (frontal depression). The larger the size of nidus is, the higher the shunt flow through nidus is, therefore, there were no significant difference of mean rCBF between the affected and non-affected hemisphere independently of the size of nidus. But in the area adjacent to AVM nidus, particularly the nidus over 20 cm3 of volume, surrounding ischemic focus was noticed. And it was thought that brain swelling due to the normal perfusion pressure break through may occur when the nidus over 20 cm3 was removed. The reduction of rCBF of the non-affected cerebral hemisphere was noticed in the cases with nearly medical seated AVM and the rCBF reduction of the non-affected or affected hemisphere was noticed in the cases with posterior fossa AVM. There was similarity between the results concerning the hemodynamic status obtained by 133-Xe inhalation cerebrograph and stable xenon enhanced CT. But 133-Xe inhalation cerebrograph was less useful for estimation of cerebral hemodynamics than the stable xenon enhanced CT, because overestimation of rCBF was noticed in 133-Xe inhalation cerebrograph.     

Endovascular treatment of cerebral arteriovenous malformations

The authors report their experience with the endovascular approach of AVMs. Although the followup is short, the approach to the lesion and the morbidity related to the technique is low.41 patients are reviewed. The most important feature of this series is that only 17 patients had previously bled. 27 had seizures and the remaining intractable headaches or progressive deficits. Only 4 patients were operated on following embolization.Clinical results are good, although few anatomic cures have been obtained by embolization alone (5 cases). However, the morbidity was moderately important (19%) per patient, 2/3 of which were totally regressive within a month. One death occurred during the procedure for a young male with a nonsurgical posterior fossa brain AVM which had bled two times prior to the endovascular treatment.Topographic presentation of our results is the following: Pure cortical (13 cases), cortico-ventricular (17 cases), deep-seated (without vein of Galen) (2 patient), Posterior fossa (3 cases).     

Multiple medullary venous malformations decreasing cerebral blood flow: case report

A rare case of multiple medullary venous malformations in the right cerebral hemisphere is reported. The literature review yielded only one case of multiple medullary venous malformations. Computed tomography scan showed multiple calcified lesions with linear contrast enhancement representing abnormal dilated vessels and mild atrophic change of the right cerebral hemisphere. Single-photon emission computed tomography using N-isopropyl-p-(123I) iodoamphetamine demonstrated decreased cerebral blood flow in the right cerebral hemisphere.     

Multiple cerebral cavernous malformations associated with extracranial mesenchymal anomalies

Cerebral cavernous malformations (CCM) are common hamartous dysplasias characterized by abnormally dilated vascular channels. CCM mostly occur sporadically, and multiple occurrence of CCM is highly suggestive of a genetic origin of the disorder. Typical clinical symptoms are seizures, hemorrhages, focal neurological deficits, and headaches. Three genes have so far been described that are responsible for most cases of familial CCM and more than half of the sporadic cases with multiple CCM (CCM1–3). The coincidence of CCM and other vascular anomalies has been described before. The present review discusses the association of CCM with mesenchymal anomalies, with special emphasis on the possible common pathogenetic pathway for CCM and atrial myxomas. An illustrative case is presented in which CCM occurred together with different dysplasias (multiple CCM, liver cavernoma, and cardiac atrial myxoma), which are all thought to arise from abnormal mesenchymal cell differentiation processes.     

大型脑动静脉畸形的显微外科手术治疗

目的：探讨并总结大型脑动静脉畸形（AVM）的显微外科手术治疗策略及手术要点。方法回顾性分析71例大型 AVM病例,按照 Spetzler-Martin 分级,3级者31例,4级者25例,5级者15例,均采用显微手术治疗,其中30例有高出血风险者行术前血管内栓塞。65例全切,6例少量残留,2例残余动静脉畸形外院行伽玛刀治疗。出院行格拉斯哥预后评分（GOS）评价预后。结果1例术前持续昏迷术后轻度改善,余病例主要并发症有偏盲、轻度失语、肌力下降及癫痫等,术后均得到较好恢复。无长期昏迷及死亡病例。术后随访 GOS,恢复良好61例（85．9％）,中残8例（11．2％）,重残2例（2．8％）。结论大型 AVM治疗风险较高,显微外科手术是治疗 AVM的有效手段,术前精确的判断及术中精细的操作是手术成功的关键,术前血管内栓塞为 AVM的治疗提供了新思路。     

Treatment of arterio-venous high-flow vascular malformations of the mandible

Arterio-venous vascular malformations (AVM) rarely occur in craniofacial bones. The most frequent location has been reported in the mandible. The first clinical evidence of the lesions can be a fatal hemorrhage, occurring spontaneously or subsequent to dental therapy. Lack of knowledge about these lesions among specialists dealing with the oral and maxillofacial regions can lead to fatal complications. The study presents the successful multidisciplinary management of two cases of mandibular AVM using embolization, sclerotherapy and bone reconstruction, a major challenge owing to the substantial risk of morbidity, recurrence by recanalization and revascularization, neurologic deficits and mortality. There were no complications over a follow-up period of 12 years.     

Intraoperative evaluation of cerebral hemodynamics using directional Doppler technique. Part 1: Arteriovenous malformations.

The use of a pulsed echo Doppler technique during surgery for cerebral arteriovenous malformation is described. The equipment and the methods employed are presented. The main advantages are easy determination of flow direction and pattern of the vasculature involved, allowing a precise discrimination between inflow and outflow channels. Deep-seated malformations, not visible at the brain surface, can be located with the Doppler technique. The ultrasound probe was placed on the brain surface with a slight pressure on the intact pia mater. The precise direction and depth of the malformation could be determined in relation to the recording site. This facilitated the planning of cortical incisions, identification of vessels involved, and the vascular procedure to be employed.     

两种血流动力学管理策略术后早期对肝移植受者的影响

目的 探讨采用Swan-Ganz导管与中心静脉导管监测血流动力学参数指导治疗对肝移植患者术后早期的影响.方法 107例肝移植受者中102例入选,随机数字表法分为肺动脉导管(PAC)组(52例),中心静脉导管(CVC)组(50例).两组均监测中心静脉压、平均肺动脉压、心率、平均动脉压、肺动脉嵌顿压、心输出量和氧输送量等,按既定血流动力学管理方案用血管活性药物或持续静脉-静脉血液滤过治疗控制各项指标在目标范围内.结果 两组患者的基本资料的差异无统计学意义.PAC组住重症监护病房期间死亡率为7.7%,CVC组为4.0%.PAC组术后28 d死亡率为11.5%,CVC组为8.0%.PAC组ICU住院时间中位数为2.5 d,CVC组为2 d.PAC组机械通气时间中位数为26.5 h,CVC组为24 h.以上各项指标的差异均无统计学意义(P＞0.05).两组术前及术后第1、5天肾功能和肝功能以及术后第1、2、3天血乳酸的差异均无统计学意义(P＞0.05).PAC组发生-过性室性心律失常共26例;CVC组发生2例.结论 肝移植术后采用Swan-Ganz导管监测血流动力参数指导治疗并不优于采用中心静脉导管监测中心静脉压的方法,反而增加-过性室性心律失常的发生率.     

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.     

Spinal cord arterio-venous malformations in children: a rare but important diagnosis

Spinal cord arterio-venous malformations (AVMs) are rare and the diagnosis is often delayed or missed. We describe two cases presenting in different ways, as subarachnoid haemorrhage (SAH) or myelopathy. A catheter angiogram confirmed the diagnosis following which they were treated with coil occlusion or embolisation, or a combination of both, without any complications.     

Cerebral hemodynamics and metabolism in patients with cerebral arteriovenous malformations: an evaluation using positron emission tomography scanning

OBJECT: The purpose of this study was to evaluate cerebral hemodynamic and metabolic features in patients with arteriovenous malformations (AVMs) by using positron emission tomography (PET) scanning. METHODS: Twenty-four patients with supratentorial cerebral AVMs participated in PET studies in which 15O inhalation steady-state methods were used. The authors recorded the values of regional cerebral blood flow (rCBF), regional cerebral blood volume (rCBV), the regional oxygen extraction fraction (rOEF), and the regional cerebral metabolic rate of O2 (rCMRO2) at three designated regions of interest (ROIs) in each patient. These ROIs included perilesional (ROI-p), ipsilateral remote (ROI-i), and contralateral symmetrical (ROI-c) brain regions. To identify the factors that exert a direct effect on the hemodynamics of brains affected by AVM, we also separated the lesions according to their size and flow type shown on angiograms, and grouped the patients according to the presence or absence of progressive neurological deficits. We then compared the PET parameters at different ROIs in individual patients and evaluated the mean values obtained for all 24 patients according to AVM flow type and size, and the presence or absence of progressive neurological deficits. CONCLUSIONS: Overall, mean rCBV and rOEF values were significantly higher in ROI-p than in ROI-c (p = 0.00046 and p = 0.015, respectively). No significant differences were seen between the ROI-i and ROI-c with respect to rCBF, rCBV, and rOEF. Mean rCMRO2 values were similar in the three ROIs; however, the mean rCBF was significantly lower in the ROI-p than in the ROI-c in patients with high-flow AVMs (p = 0.019), large AVMs (p = 0.017), and progressive neurological deficits (p = 0.021). Furthermore, the mean rOEF values were significantly higher in the ROI-p than in the ROI-c in patients with high-flow AVMs (p = 0.005), large AVMs (p = 0.019), and progressive neurological deficits (p = 0.017). The PET studies revealed hemodynamic impairment characterized by decreased rCBF and increased rOEF and rCBV values in the ROI-p of patients with large, high-flow AVMs regardless of whether they exhibited progressive neurological deficits.