Ricardo Garcia-Monaco

Cerebral arteriovenous malformations in children - Management of 179 consecutive cases and review of the literature

Over the past 10 years (1982–1992), we have been actively involved in the management of 179 cerebral arteriovenous malformations (CAVMs) in children and infants. Seventy-seven were true vein of Galen malformations (VGAMs) and 102 were pial AVMs (PAVMs), i.e., developed in the subpial space. Hemorrhage occurred as the first symptom in 50% of the children with pial AVMs, but was present in none of the VGAM cases. Only 31 children were found to be unsuitable for endovascular treatment, and in 124 cases embolization was indicated as the primary treatment (104 embolization performed). Only 21 children underwent a direct surgical approach (none in the VGAM group). In the embolized group in whom treatment has been completed (n = 56), 8 children died, 39 have an anatomical cure, and 34 are clinically normal. In the group under treatment (n = 56), 16 are not normal. The problems are timing and the aims (total or partial treatment) of the therapeutic procedures. In the nonembolized group (n = 31), 8/13 of the pial lesions were operated on (no mortality, 2 patients with moderate neurological deficits). In the VGAM group 13/18 died and 4 had spontaneous thrombosis (only 1 is neurologically normal). In the nonembolized group 13 lesions have been completely excluded, but only 5 patients are neurologically normal. This fact again stresses the need for prognostic evaluation before treatment and a clear definition of the treatment aims. Analysis of a large number of published series on the management of children with AVMs (1017 cases) reveals inconsistencies that hamper proper evaluation and comparison. In our experience, endovascular treatment always seems to be the best primary treatment in both VGAMs and PAVMs. However, management of children with these lesions requires a large multidisciplinary team, which is the only way of offering the most suitable and effective treatment, the sole guarantee of a good result.

Hydrodynamics in vein of Galen malformations

Forty-three patients with vein of Galen aneurysmal malformations (VGAM) referred to us for endovascular treatment between 1985 and 1990 and 335 additional cases published in the literature were reviewed with particular attention to the presence of ventricular enlargement and outcome after shunting. Hydrocephalus was the second most frequent symptom (46.8%); it is more frequent in infants (73%) than in children, adults (30%) or neonates (15%). Of the patients reported in the literature, 17.9% had undergone shunting. Within the shunted population there was an overall morbidity of 41% and a mortality of 10% (especially in the infant group). In our series 17 patients (39.5%) were shunted and a significant difference in the clinical outcome was noted between the shunted and the nonshunted group. Of the nonshunted patients, 66.6% were free of any neurological deficit or mental retardation and fewer than 5% presented with significant mental retardation. On the other hand, only 33.3% of the shunted patients had a favorable outcome and more than 15% developed significant mental retardation. Among the various causes of hydrocephalus in patients with VGAMs, such as obstruction of the aqueduct, subarachnoid hemorrhage, or ex vacuo hydrocephalus, high venous pressure may be of particular importance. In this article a physiopathological interpretation of the hydrodynamics in VGAMs is developed and a speculative explanation for CSF disorders related to ventricular shunting proposed. Treatment of hydrocephalus in VGAMs can be achieved through obliteration of the malformation or at least diminishing the venous pressure; surgical ventricular shunting does not have to be the first treatment of hydrodynamic disorders associated with VGAMs, especially in infants.

Multifocal dural arteriovenous shunts in children

The authors present four consecutive cases of multiple dural arteriovenous (AV) shunts in children. This entiry represents a rare but severe clinical situation. the edology of the shunts is not known. There is clinical and radiological evidence that they are evolutionary lesions. The clinical presentation in this series was usually by cardiac manifestations (one case), cerebrospinal fluid disorders (two cases), neurological symptoms (three cases), including intracranial hemorrhage (two cases), and cranial bruits (four cases). No radical treatment leading to anatornical cure of all dural AV shunts was thought to be possible using current methods, including modern endovascular and surgical techniques, in any of the four cases. Therefore, treatment was only symptomatic and directed at some of the AV shunts. Targeted arterial embolization with permanent embolic agents represents the most rational technique for symptomatic relief in these patients. However, clinical recurrence often happens without evidence of recanalization. Secondary multifocal pial AV shunts opening into the abnormal sinus occurred in two of the cases; they may have been induced by venous sump from the sinus draining the dural AV shunts. Mechanical occlusion (or excision) in multiple dural AV shunts in children does not represent a satisfactory goal, as the shunts can be the expression of a more complex and yet unknown disease.

Multiple cerebral arteriovenous shunts in children: report of 13 cases

The authors present a series of 13 multiple arteriovenous malformations (MAVMs) in the pediatric population (16.9% of their overall series of brain AVMs in this group). Two types of MAVMs can be distinguished: congenital and acquired. Congenital MAVMs may be of the nidus or fistula type. They may be uni- or bilateral, placed in one or several cerebral lobes, separated or close one to another, or even systematized (Wiburn-Mason syndrome). The symptoms created by these MAVMs are the same as those encountered in the presence of other AVMs, with hemorrhage as revealing symptom in 31% of patients. The responsibility of one particular nidus in the onset of clinical signs is often difficult to determine. From an angioarchitectural point of view, it seems that venous drainage changes are mainly responsible for the symptomatology. The natural history of these MAVMs is difficult to assess; spontaneous regression has been noted in 15% of cases. Acquired cerebral MAVMs can be due to angiogenesis (“sprouting” or “non-sprouting”) around a true AVM because of previous hemorrhage or ischemia, or to pial shunts associated with dural arteriovenous malformations. The treatment of MAVMs is difficult. Embolization seems to the authors the best therapeutic modality available, as surgery or radiosurgery are often unable to treat these multifocal lesions. Anatomical cure is rarely obtained; the therapeutic strategy has to be targeted on the symptomatic lesions.

Deep venous drainage in great cerebral vein (vein of Galen) absence and malformations

SummaryWe report two types of venous patterns associated with great cerebral vein (vein of Galen) absence or unavailability. Developmental venous anomalies or vein of Galen arteriovenous malformations (VGAM) serve as an illustrative material. A diencephalic pattern that collects the thalamo-striate veins into the tentorial sinus is recognized in most VGAM. A telencephalic arrangement connecting the striate veins with the rostral afferents to the basal vein is less frequent. Both patterns reproduce embryonic stages preceeding the development of the great cerebral vein, thus confirming Raybauds hypothesis that in VGAM the pouch is not the vein of Galen but the medial vein of the prosencephalon. The prognostic value of each pattern can then be appreciated and the therapeutic strategies rationalized; some unexplained complications of the venous approach for non selected VGAM can thus be avoided.

Embolization of Vascular Lesions of the Head and Neck

Vascular lesions of the head and neck are rich in clinical and therapeutic features and their management usually requires a multidisciplinary approach. Head and neck surgeons, stomatologists, plastic surgeons, neurosurgeons, orthodontists, pediatricians, and radiologists are often involved in their management. Radiologists performing endovascular therapy not only should be comfortable with catheter techniques and embolic materials, but also should have a thorough clinical and anatomic knowledge of this region. This allows adequate patient selection with precise definition of therapeutic goals and avoids potential complications. We will therefore discuss some general principles of functional vascular anatomy and embolization techniques in the head and neck region, as well as specific pathologies amenable to endovascular therapy, i.e., vascular malformations, vascular proliferations, and traumatic lesions.

Vein of Galen Aneurysmal Malformation: Patient Selection and Endovascular Management

The literature has provided us with a large number of case reports and few series or reviews1–6 of so-called arteriovenous malformations of the vein of Galen (AVMs of VG). All the cases regrouped presented with intracranial arteriovenous shunt (AVS) and an ectatic vein in the pineal region; however, the diseases involved were different and yet not differentiated. Clarisse1 was among the first to suggest that true and false AVMs of VG could be distinguished, but still he included in the group of true malformations some cases that should have been excluded. In our earlier series5 of patients, we separated the lesions draining into the venous pouch with no reflux into the cerebral veins from those where reflux from the pouch into the usual tributaries of the Vein of Galen was noted (Fig. 7.1). We proposed to call the latter cerebral AVMs with vein of Galen ectasia, or vein of Galen aneurysmal dilatation (VGAD). The remaining group corresponds to vein of Galen aneurysmal malformations (VGAMs). The only common point of all these cases was the concept of venous obstacle, either inborn or acquired7 (Fig. 7.2).

Prevention of Stroke from Cerebral Vascular Malformations

Cerebral vascular malformations (CVMs) produce both hemorrhagic and ischemic stroke. Cerebral hemorrhage is the most frequent type of stroke, and almost 50% of arteriovenous malformations (AVMs) present with parenchymatous hematoma. Ischemic stroke is less frequent but is also seen in large AVMs or arteriovenous fistulas. It is commoner in children and is due to venous thrombosis within the vascular lesion, arterial “steal,” or associated Moya-Moya or coagulation disturbances.