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Because of their rarity,we probably discover CNS symptoms mostly after the patients have already presented to the referring specialist with
other symptoms. This may have led to an overestimation of the incidence
of neurological events in CAMS disease.
Therapeutic management of the cerebral AVMs and AVMs along
the optic pathways related to CAMS is particularly challenging. We
would suggest targeted embolization in an attempt to exclude weak
angioarchitectural structures or to reduce the AVS in the least
eloquent areas in symptomatic patients who are clinically significantly
affected.
6.2.3 Facial AVMs, Nasal AVMs,and Mandibular AVMs
Facial AVMs and mandibular AVMs are hallmark locations of CAM disease. The full spectrum of the syndrome was present in one-third of the
cases in the review of Jiarakongmun et al. review (2002). Bhattacharya et
al. (2001) noted that four out of 15 had a facial AVM in his series. The
presence of the facial vascular lesion can be difficult to recognize or clinically silent, sometimes representing a small stable red spot or angioma
since infancy or the early childhood period. Then an unknown trigger
occurs promoting growth of the lesion with revealing symptoms such as
bleeding of the gums or mass effect resulting in facial asymmetry, often
during adolescence.
The angioarchitecture of facial or mandibular AVMs in CAMS look
similar to sporadic cases. They usually present as an arteriovenous fistula or nidus-type arteriovenous malformation with intranidal fistulas.
Large proximal arterial aneurysms were noted in our series despite relatively slow flow or small facial or mandibular AVMs (Fig. 6.7).It should be
pointed out that sporadic isolated maxillary or mandibular AVMs are not
associated with external carotid artery aneurysms regardless of their
flow.
It is therefore apparent that facial AVMs and intracranial AVMs in
CAMS patients are different in terms of angioarchitecture and natural
history from sporadic counterparts.
In the case of the Jiarakongmun et al. (2002) case, a proximal unruptured arterial aneurysm in the sphenopalatine fossa far away from distal
nasal AVMs prompted preventative treatment to reduce the risk of severe
epistaxis. Maxillary or mandibular AVMs with intraosseous venous lakes
or pouches are also at risk of gum bleeding and severe hemorrhages after
tooth extraction (Fig. 6.15).
Hemorrhage associated with facial and mandibular AVMs was the
revealing symptom in one of our cases, and in most series the posterior
fossa lesions were identified only after screening (Wong et al. 2003; Haw
et al. 2003;Yasuhara et al. 1999) (Fig. 6.6).
6Cerebrofacial Arteriovenous Metameric Syndrome382
383Facial AVMs, Nasal AVMs, and Mandibular AVMs
Fig. 6.15A–D. CAMS 2. A 9-year-old girl presented with the onset of right-sided
hemiparesis. Investigations revealed an intraventricular hemorrhage arising from an
AVM of the left basal ganglia (A). She was reviewed annually and a recent decline in
visual acuity was detected in the left eye together with an inferior quadrantanopia of
the right visual field. Significant maxillary involvement with bone hypotrophy (B, C)
and rapid expansion over 2 years of the extracranial location led to embolization with
glue to prevent epistaxis (D). The maxillofacial lesion was considered to present the
most immediate danger, with the possibility of life-threatening hemorrhage at the
loss of her molar baby teeth
6.2.4 Investigation for CAMS Patients
Proper investigations for patients suspected of having CAMS will vary
depending on the clinical manifestation associated with the revealing lesion. The patients suspected of having CAMS 1 who present with hypothalamic AVMs should be investigated in detail for nasal AVMs and olfactory or corpus callosum AVMs by physical examination and detailed MRI
examination.
For CAMS 2, patients who present with diencephalic lesions such as
chiasmatic or optic nerve AVMs with progressive visual loss should be investigated for maxillary lesions including AVMs or dysplastic aneurysms
involving the external carotid system to prevent life-threatening epistaxis
from an aneurysm of this type.
For CAMS 3, patients presenting with cerebellar AVMs should be investigated for mandibular lesions such as high-flow AVMs, which could
lead to severe bleeding after tooth extraction in the adolescent.
Conversely, patients presenting with facial vascular lesions with characteristic high-flow AVFs or dysplastic aneurysms in the nasal maxillary
or mandibular areas should be investigated for possible coexisting
asymptomatic intracranial AVMs.
6.3 CAMS and Angiogenic Activity
Facial involvement varies from a faint cutaneous discoloration caused by
a venous malformation to the full-fledged maxillofacial or mandibular
AVM, which may present with life-threatening hemorrhage in addition to
severe cosmetic and psychological problems (Gibo et al. 1989) (Figs. 6.7,
6.12, 6.15).Preventive treatment of such lesions is recommended.
The angioarchitecture of facial or mandibular AVMs in CAMS is not
significantly different from the sporadic cases.They can either present as
an arteriovenous fistula or as an nidus-type of arteriovenous malformation.An interesting finding is the presence of arterial aneurysms
(Fig. 6.7) arising from external carotid artery branches. Since the flow in
the AVM is not very high and the external carotid system (facial and maxillary arteries) is involved, the dysplastic (angiogenic or proliferative)
origin of these aneurysms is supported, similar to what can be seen
in PHACES syndrome (see Chap. 12, this volume) (Table 6.3). Unlike
CAVMs where angiogenesis is not seen unless special traumatic, hemodynamic, ischemic, or other triggers interfere, the way CAMSs present
and evolve over the years is peculiar.In particular, there is an obvious increase in AVM size in the maxillofacial region, de novo locations in the
brain, or apparent extension of previously demonstrated ones. While a
single sporadic CAVMs related to a late causative trigger does not become
larger (all the cells involved show their common impairment),CAMSs,on
the other hand, since they are generated by an earlier causative trigger
(involving groups of migrating and nonmigrating cells), maintain their
capacity over the years to reveal their full extent through a pseudogrowth or proliferation.
6Cerebrofacial Arteriovenous Metameric Syndrome384
Obviously the facial AVMs and intracranial AVMs in CAMS patients
are different in terms of angioarchitecture and natural history
(Jiarakongmun et al.2002) from sporadic AVMs. The different expression
of the disease and the various locations are the result of the relationship
established by the cells during their migration.
Although belonging to the AVM group of disorders,the successive development of the lesions, their being intermingled with normal tissue,
and the presence of dysplastic aneurysms suggest a malformative target
closer to the arterial side than usually associated with CAVMs (see
Chap. 2, this volume), and an early causative timing impacting the still
poorly differentiated arteriovenous structures.
The resulting phenotypes will combine AVS characteristics with arterial ones such as preserved active angiogenesis and aneurysmal development. Slightly more proximal on the vascular tree to be developed, one
would place the PHACE syndrome with the combination of various proliferative properties and fewer AV malformative features (Scheme 6.1).
More distally on the tree,one would expect CVMS (Ramli et al. 2003) or
Sturge-Weber syndrome,which associates venolymphatic malformations
without angiogenesis and aneurysm. All these syndromes share the migrating pattern of the neural crest and cephalic mesoderm along their
three main paths. Multiple hemangiomas can also be analyzed with this
geographical distribution in mind (Waner et al. 2003) (see Chap. 8, this
volume) (Fig. 6.16). SAMS 1–31 belong to the same group; however, the
peculiar nature of the vessel’s embryological origin make them combine
several types of expression from arteriovenous to purely venous; yet they
keep some degree of angiogenic potential with nidus growth and
aneurysm formations (Figs. 6.17,6.18).
385CAMS and Angiogenic Activity
Ta ble 6.3. Postulated relation between metameric syndromes and neural crest/mesoderm contribution, lymphatic to
arterial impact, and proliferative behavior
Ly mph at ic
a
PWS
a
Cartilage Membrane AV Angio- Arterial
malformation bone
a
bone
a
shunt
a
genesis
a
aneurysm
a
Mirror aneurysm
b
––––––+
PHACES
b
–––––++
CAMS 1, 2
b
–––++++
CAMS 3
b
––+++++
CVMS 1–3
b
++++–––
SAMS 1–31 + + + + + + +
a
From less angiogenic to more angiogenic (from left to right).
b
Neural crest and mesoderm to mesoderm alone; craniocaudal (from up to down).
PWS: Port wine Stain.
6Cerebrofacial Arteriovenous Metameric Syndrome386
Fig. 6.16. The nonrandom distribution of facial hemangiomas. Based on their clinical
photographs, 232 of the hemangiomas were mapped on a facial schema.The 55 diffuse
hemangiomas showed a segmental tissue distribution and thus were designated as
frontonasal (27%), maxillary (35%), or mandibular (38%). Note the three territories
found by Waner, although he did not refer to the geotropism identified in the CAMS.
The identical mapping point to the reality of these boundaries not only for malformative vascular lesions but also for proliferative lesions.(From Waner et al.2003)
Scheme 6.1. Vascular diseases according to the arterio-veno-lymphatic tree
387CAMS and Angiogenic Activity
Fig. 6.17. A SAMS 1/2.Typical aspect of the same segmental logic applied to the first
segment caudal to the third cranial territory (B, C)
6Cerebrofacial Arteriovenous Metameric Syndrome388
Fig. 6.18A–D. A 26-year-old patient who presented with a chiasmatic syndrome and
a cleft palate.Axial CT (A). Note the contrast-enhanced lesion of the area of the anterior commissure. Note the hyperemic cleft margins (arrowheads). B Selective injection of the ipsilateral facial artery. Note the hyperemic cleft margins (arrowheads).
The upper lip also has a hyperemic zone (arrow). Note the medial branch to the inferior labial arcade (curved arrow). C,D Internal carotid injection shows an subcallosal
suprachiasmatic lesion (arrowhead), suggesting associated AVM. The topography of
both midline lesions may correspond to a CAMS 1-like syndrome
7.1 Introduction 389
7.2 Classifications 390
7.2.1 Age Groups 392
7.2.2 Disease Groups 392
7.3 Dural Sinus Malformations 396
7.3.1 DSM with Giant Pouches 398
7.3.1.1 Fetal and Postnatal Changes of Sinuses 398
7.3.2 DSM of the Jugular Bulb 434
7.4 Infantile Dural Arteriovenous Shunts (AVS) 436
7.5 Adult Type of Dural Arteriovenous Shunts in Children 444
7.6 Other Dural Shunts 447
7.6.1 Vein of Galen Aneurysmal Malformation 447
7.6.2 Dural Supply to Pial Cerebral Arteriovenous Malformations 447
7.6.3 Proliferative Angiopathic Disease 448
7.6.4 Systemic Disorders 448
7.6.5 Recurrence in Intradural AVS and Secondary Transdural Supply 449
7.7 General Remarks on Treatment 451
7.1 Introduction
Few reports have addressed the entity of dural arteriovenous shunts
(DAVS) in the pediatric age group (Albright et al. 1983; Garcia-Monaco
1991c; Morita et al. 1995; Kincaid et al. 2001; Barbosa et al. 2003). These
authors reviewed mostly the English literature on the subject and some
reports included individual therapeutic attempts or described pediatric
cases as part of an adult series. Discussion in the past tended to focus on
the issue of the congenital vs.acquired character of the disease, and many
authors referred to the same classic observations.Only rarely were pediatric examples used to help understand this disease as it affected children. In contrast, it has been a frequent presumption that certain adult
circumstances likely also apply to children. Similarly, authors have tried
to recognize in pediatric cases an adult pattern to justify the use of more
familiar management strategies or tools.Application of technical experience in adults to the pediatric practice have ignored the specificities of
this population and delayed appropriate steps that need to be taken
toward understanding and treatment.
7Dural Arteriovenous Shunts
7.2 Classifications
Many DAVS classifications are available in the literature.Several of those
classifications are being used in the endovascular community but none
applies directly to the pediatric age group. Pediatric DAVSs are themselves evolutive and in addition develop on an evolving (maturing) vascular system. Understanding the mechanisms for symptoms and the
chronology of events is more relevant in the management of pediatric
DAVSs then memorizing classifications that are not applicable.
It was Castaigne et al. (1976) who stressed the role of the pial venous
drainage in understanding the pathophysiology of neurological symptoms in adult patients with DAVS. Since then, few reports have added to
this fundamental contribution, until recently the analysis of the natural
history of DAVS in adults has been described (Davies et al. 1996,1997a, b;
Satomi et al. 2002; van Dijk et al. 2002). DAVSs involving the superior
sagittal sinus (SSS) and posterior sinusal confluents are often lumped together with cavernous plexus and anterior cranial fossa locations, yet
they differ anatomically, histologically,physiologically,and are also likely
to be biologically different and should therefore not be reported as a homogeneous group.Attention paid to the flow direction in the venous outlets has outlined various types of anatomic arrangements.Clearly,the only important predictive feature for future neurological manifestations in
adults is the presence or absence of cerebral venous reflux at a given moment. Such basic observations would apply to pediatric cases provided
that the maturation of the venous system had been achieved; however,in
children neurological symptoms can also occur without pial venous reflux.Therefore, the understanding of how the brain and DAVS interact in
children cannot be learned only from the analysis of the lesion itself but
requires that the specifics (maturation,etc.) of the cerebral vasculature at
that moment in time be scrutinized and analyzed. In children, any intracranial AVS may create a shift in the vascular maturation processes,
resulting in a shift for that individual’s final vascular equilibrium. The
shift may not compromise the physiological needs on a short-term basis
but can weaken the individual vascular system, making it vulnerable or
less flexible to various triggers, whether they be hemodynamic, immune,
hormonal, or others.
Arteriovenous shunts involving the dura and the epidural space, i.e.,
the different diseases that can be labeled, although improperly, pediatric
DAV shunts,include the following:
Dural sinus malformations (DSMs)
Nontraumatic infantile DAVS
Nontraumatic adult type of DAVS (osteodural, sinusal-dural, dural-
subdural)
Tr aumatic epidural AV communications
Induced DAVS (associated with cerebral AV malformations, sinusal
high-velocity flow conditions, proliferative angiopathic diseases)
Their causes and the degree of interference with the rest of the vascular
system will be different, as the biological profile and reactivity are different in each of these situations.
7Dural Arteriovenous Shunts390
391Classifications
Fig. 7.1. Schematic representation of the arteries to the skull base and adjacent dura
A. Opthalmic Artery
a
1
Intraorbital portion 1
a
2
Intraorbital portion 2
a
3
Intraorbital portion 3
a
4
Lateral muscular artery
a
5
Lateral ciliary artery
a
6
Central retinal artery
a
7
Medial ciliary artery
a
8
Supra orbital artery
a
9
Lacrymal artery
a
10
Recurrent tentorial artery
a
11
Deep recurrent ophthalmic artery
a
12
Recurrent meningeal artery
a
13
Meningo ophthalmic artery
a
14
Posterior ethmoidal artery
a
15
Anterior ethmoidal artery
a
16
Anterior falcine artery
a
17
Jugum sphenoidale branch
ab
8
Anterior frontal meningeal
ab
9
Anterior frontal meningeal
B. Middle Meningeal Artery
b
1
Cavernous branch
b
2
Petrous branch
b
3
Basal tentorial branch
b
4
Posterior fossa branch
b
5
Petro squamosal branch
b
6
Parieto occipital branch
b
7
Middle cranial fossa branch
b
8
Sphenoidal branch
b
9
Frontal branch
b
10
Te ntorial branch
b
11
Cavernous branch of the
accessory meningeal artery
ba
9
Meningo lacrymal artery
C. Ascending Pharyngeal Artery
c
1
Jugular branch
c
2
Hypoglossal branch
c
3
Clival branch
c
4
Inferior petrosal branch
c
5
Cerebello pontine angle branch
c
6
Midline anastomosis
c
7
Odontoid arterial arch system
c
8
Foramen magnum branch
c
9
Carotid branch
c
10
Cerebellar fossa branch
D. As cending Pharyngeal Artery
d
1
Mastoid branch
d
2
Cerebellar fossa branch
d
3
To rcular branch
d
4
Cerebello pontine angle branch
E. Internal Carotid Arter y
e
1
Meningo hypophyseal trunk
e
2
Infero lateral trunk (I.L.T.)
e
3
Antero medial branch (I.L.T.)
e
4
Antero lateral branch (I.L.T.)
e
5
Posterior branch (I.L.T.)
e
6
Recurrent artery of the froamen lacerum
e
7
Marginal tentorial artery
e
8
Lateral clival artery (medial branch)
e
9
Lateral clival artery (lateral branch)
e
10
Postero inferior hypophyseal artery
e
11
Medial clival artery
e
12
Capsular artery
F. Ve rt eb ra l A rt er y
f
1
Artery of the falx cerebelli
f
2
Posterior meningeal artery
f
3
Cerebellar fossa branch
f
4
Subarcuata artery
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