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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3644_Библиотеки_им_академика_М_И_Перельмана
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Combined approaches, including presurgical embolization, will depend on the availability of expertise in a given institution (Fig. 5.33).The
number of postoperative epilepsy cases is high and could possibly be reduced with presurgical embolization. An obvious indication for surgery
is still the removal of large hematomas with an unstable clinical status or
a lesion that cannot be reached by catheterization. Obviously, technical
skills vary between individuals performing the embolization, as they do
from one surgeon to another. In young patients,we favor the combination
of embolization plus surgery, as the vulnerability to radiation is high in
children.
5.7.2.2 Radiation Therapy
There are few reports of radiotherapy in this age group (Shin et al. 2002;
Smyth et al. 2002).We have used radiation in combination with embolization after control of demonstrated weak portions of the lesions in a few
cases (Figs. 5.28, 5.34) and exceptionally as the primary form of treatment (Fig. 5.35). Its indications in this age group are certainly limited.
Among such indications, we have to consider are the nonfeasibility of
other techniques, the maturation stage of the brain, and the risks associated with conservative treatment.We tend to discuss radiation therapy in
adolescents rather than young children in view of the risk involved on a
maturing brain (Table5.10).
Some lesions such as hemorrhagic angiopathy, mimicking CAVM and
presenting with subcortical hemorrhage, should be irradiated following
angiography and possible targeted embolization (Fig. 5.36).On the other
hand, proliferative angiopathies and most CAMSs should not be treated
with radiation (Fig. 5.37), as eloquent brain is intermingled with the
vascular spaces (see Chaps. 6 and 18,this volume).
5Cerebral Arteriovenous Malformations352
353Radiation Therapy
Fig. 5.34. A, B Ty pi c al partial
targeted embolization directed
to a false aneurysm at the acute
stage in a ruptured brain AVM.
C Angiogram after embolization.Secondary management
can then be discussed, whether
conservative or radiation
therapy
5Cerebral Arteriovenous Malformations354
Fig. 5.35A–D. A 9-year-old girl presented with small left thalamic and intraventricular hemorrhage and made a full neurological recovery. Left internal carotid angiogram in lateral (A) and frontal (B) views demonstrated small AVM within the me-
dial aspect of the thalamus. Stereotactic radiosurgery was performed and 2 years later the follow-up angiogram in lateral (C) and frontal (D) views demonstrated
obliteration of the AVM.E,F see p. 355
355Radiation Therapy
Fig. 5.35EF. (continued) MRI prior to (E) and 2 years after radiosurgery (F) also
shows the impact of radiosurgery
Ta ble 5.10. Review of the literature on radiotherapy of pial arteriovenous malformations
Authors Upper Study Patients Operations Total exclusion Oper- Remarks
age period for Neuro- Neuro ative
limit CAVM/ logically logically mor(years) VGAM normal abnormal tality
(n)(n)(n) (%) (n) (%)
Altschuler 18 1987–1988 18 18 – 3 17 0 In another
et al. 1989 11 patients,no
angiography
was performed
Loeffler 15 1986–1988 5 5 – 3 60 0 One patient not
et al. 1990 yet scheduled
for angiography
Colombo 18 1984–1989 24 24 – 11 46 0 In six patients, no
et al. 1989 angiography
was performed
To tal 1984–1989 47 47 – 17 60 0 18 Patients with
no FU
angiography
AVM, arteriovenous malformations; CAVM, cerebral AVM; VGAM, vein of Galen aneurysmal malformation; FU, followup.
5Cerebral Arteriovenous Malformations356
Fig. 5.36A–E. A 10-year-old girl with sudden headaches with
aphasia and right-sided hemiplegia. A CT shows a subcortical
hematoma.The hematoma was removed surgically,resulting
in good clinical recovery: slight underuse of her right upper limb
was noted, but right-handed writing remains. B, D CT and
angiography suggest hemorrhagic angiopathy,with typical
subcortical nidus and small draining vein.Partial targeted
embolization on the medial aspect of the nidus was done.
Radiotherapy was organized 2 months later and 12-month
follow-up angiogram failed to demonstrate any residual
lesion (D, E)
357Radiation Therapy
Fig. 5.37A–B. A 10-year-old
boy presented when 7years
old with a subarachnoid
hemorrhage attributable to
a ruptured arteriovenous malformation located on the internal face of the frontal lobe under the rostrum of the corpus
callosum beneath the lamina
terminalis (A,B).C,D see p. 358
5Cerebral Arteriovenous Malformations358
Fig. 5.37C,D. (continued)
No endovascular approach
could be performed because
of the multiple small vessels
vascularizing the lesion.
The patient was scheduled for
radiotherapy.Two years after
the radiosurgery (linear
accelorator,Lineac),the patient
underwent a new angiographic
follow-up that demonstrated
the complete exclusion of the
arteriovenous malformation
(C, D).Six months after the
radiosurgery,the patient
presented right blindness
with no intracranial hypertension, from which he has
not recovered
6.1 Introduction 359
6.2 Clinical Manifestations 374
6.2.1 Retinal AVMs and AVMs Along the Optic Nerve and Chiasm 374
6.2.1.1 Retinal AVMs 374
6.2.1.2 Optic Nerve and Chiasmatic AVMs 376
6.2.2 Cerebral AVMs 376
6.2.3 Facial AVMs, Nasal AVMs, and Mandibular AVMs 382
6.2.4 Investigation for CAMS Patients 384
6.3 CAMS and Angiogenic Activity 384
6.1 Introduction
As already stressed in the previous chapters,the generic name CAVM encompasses various entities that, although treated with the same tools, are
completely different disorders. The target and the timing of the primary
impact are likely to provide some insight into the understanding of what
were believed to be random associations of multiple AVMs. The historical descriptions of cerebrofacial-associated lesions have resulted in the
identification of classic syndromes: Wyburn-Mason, Bonnet-DechaumeBlanc, Sturge-Weber, all of them involving the orbit (Fig. 6.1).
The condition of retinal arteriovenous malformation was first described by Magnus in 1874 and was long regarded as a mere ophthalmological curiosity.In 1932,Yates and Payne described a patient with retinal
and cerebral AVMs, but based on a single patient could not identify a syndrome.An association between arteriovenous malformations of the face,
retina,and brain was first recognized by Bonnet,Dechaume,and Blanc,in
Lyon,France, who reported two cases in 1937. Six years later, at Queen
Square in London, Wyburn-Mason reviewed all cases previously described and added nine further examples in a detailed study.The association of retinal, facial, and cerebral vascular malformations became
known as Bonnet-Dechaume-Blanc syndrome in France and continental
Europe, and as the Wyburn-Mason syndrome in the English literature.
The degree of expression of the syndromes’components varies,both clinically and morphologically. Thus the most fully expressed cases have
maxillofacial AVMs, in addition to the orbital and intracranial lesions,
and are susceptible to life-threatening epistaxis or gingival bleeding in
addition to the risks of blindness or cerebral hemorrhage. Some confusion has existed regarding the use of the two names, the term “Bonnet-
6Cerebrofacial Arteriovenous
Metameric Syndrome
Dechaume-Blanc” sometimes being preferred for the more extreme end
of the disease spectrum, which includes high-flow maxillofacial AVMs.
Careful reading of the original articles,however, confirms that both syndrome descriptions referred to the same condition.The two eponyms of
the syndrome can thus be used interchangeably.The syndrome is usually
classified together with the neurocutaneous syndromes or phakomatoses
(neurofibromatosis, Divry-van Bogaert syndrome, Sneddon syndrome,
or tuberous sclerosis). This classification, however, tells us more about
our inclination to classify than about the nature of the condition itself,
the various phakomatoses being of very different morphology and etiology. Unlike neurofibromatosis or tuberous sclerosis, an inherited basis
for CAMS has never been described. This does not exclude this possibility,but the absence of a family history with similar AVMs makes a lesion
arising downstream from a germ-line disorder more likely.
Although a very rare condition, it still offers insight into the development of AVMs in general and the underlying segmental structure of the
developing vasculature of the brain and face.Few descriptions of the syndrome were made with full access to modern imaging techniques. Moreover,other than the original descriptions (of nine and two cases) and two
other reports of three and two cases, all the remaining descriptions were
based on single case reports. In reviewing our series of 15 cases, Bhattacharya et al. (2001) derived new diagnostic criteria as an aid to diagnosis. Underlying patterns of involvement reflecting the segmental nature
of the cerebrofacial structures were found,supporting a disorder of neural crest development (Fig. 6.2).When comparing our findings with previously published cases, we propose a new rationale for the classification of
the syndromes.
6Cerebrofacial Arteriovenous Metameric Syndrome360
Fig. 6.1. Schematic drawing
showing potential zones of
involvement: I, facial; II,
orbital; III, cerebral. Locations
of lesions within zones:
1, cutaneous; 2, maxillofacial;
3, retina; 4, optic nerve;
5, hypothalamus/chiasm/
hypophysis; 6, thalamus;
7, occipital lobe; 8, midbrain;
9, cerebellum.
(From Bhattacharya et al.2001)
The segmentation, under the control of the hox genes, of the
rhombencephalon into rhombomeres (Orr 1887) and forebrain anlage into prosomeres (Lumsden 1989) has been substantiated in birds,
mice,and other animals and extrapolated to humans (Puelles and Rubinstein 1993). Following Le Douarin’s (1997) introduction of the
quail-chick chimera system in 1969, which provides a system for labeling cells in avian embryos and then following their migration to
their definitive sites, studies revealed the metameric nature of brain
and craniofacial structures deriving mainly from the neural crest and
plate.The initial process of vessel formation in the embryo,known as
361Introduction
Fig. 6.2A,B. Schematic aspect of cephalic ectomesoderm. Migrating cells: phenotypic acquisition. A Neural crest vascular components: during their migrating process,
a progressive modification occurs until the cell line becomes committed to a certain
cell type. The same applies to cephalic mesodermic cells; even though they originate
from regionalized mesoderm, endothelial cells acquire phenotypic specificity during
their migration. B Process by which migrating cells acquire (selection) a place and
a role by establishing a relationship with the environment. ML, medial/lateral;
CC, cranio/caudal; VD, ventral/dorsal
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