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Following the identification and localization of the site of the shunt,
the origin of the feeders and the venous drainage need to be identified
(Fig. 7.1). Regardless of the population, there will be a clear difference
between the dural sinus type of AVS at the vault and the epidural AV communications at the parasellar region. Similarities exist between the cavernous plexus and the spinal venous network, but not between the true
cranial dural sinuses and the epidural venous spinal spaces. The skull
base and its venous relationships can be followed caudally toward the
sacral region because of their similar relationships. The cavernous region,however, does not drain brain tissue at birth and therefore an early
lesion of the infantile type in the parasellar region will not have the same
cerebral consequences as a similar one at the spinal level,where radicular
veins already open into the epidural space. A malformation of the cavernous plexus is hard to conceive and indeed has never been described.
Conversely,the malformation of the sinuses or conjoined sinuses in conjoined twins will illustrate this difference (see Chap. 9, this volume).The
infantile AV shunt constitutes a separate group of lesions that will be
discussed as such.
7.2.1 Age Groups
Within the pediatric population in general, neonates and infants constitute a special subgroup as their vascular system continues to mature.
They are sensitive (exposed) to certain triggers that make them present
with specific symptoms that do not occur in older children or adults (see
Chap. 2, this volume). In particular, systemic manifestations and hydrodynamic disorders may occur with a natural progression,sometimes independent of the disease itself and remaining characteristics of the age
group. Macrocrania and its progression following jugular occlusion, and
thrombosis of slow-flowing dural pouches are examples of this specificity.The disease by itself is reported (Morita et al.1995) to have a mortality rate of 38% in the pediatric age group and the mortality rate increases
to 67% in the neonatal subgroup.
7.2.2 Disease Groups
Each of the three disease groups we will describe herein refers to features
other than strictly the age of onset or the age of main clinical expression,
since all types can be seen during the first few weeks of life. Some neonatal types may in fact not be revealed until infancy and others can be diagnosed in utero.
The three types are:
1. Dural sinus malformation (DSM) (Fig. 7.2), in which the AVS shunts
are secondary and usually accessory to the sinus malformation.
2. Infantile DAVS, often multifocal, without sinus malformation, al-
though with large sinuses and sometimes secondary jugular occlusion
(Fig. 7.3).
7Dural Arteriovenous Shunts392
393Disease Groups
Fig. 7.2A–D. Prenatal diagnosis of an intracranial cyst in a child presenting with
polypnea, aged 2months (the child could not finish his bottle). A MRI and angiography (B, C) performed at 3months demonstrated a large dural sinus malformation on
the midline. Dural and scalp arterial supply converged at the bregma suture.The cerebral medullary veins appeared to be congested.There was no evidence of cavernous
sinus capture. There was no cardiac failure (D). Partial embolization was performed
and led to a transient improvement; 10 days later, the child presented with convulsions and an intracranial hemorrhage
7Dural Arteriovenous Shunts394
Fig. 7.3A–E. An 11-year-old child presented with a right-sided exophthalmos, intracranial bruit, and vertigo. A CT shows an extensive enlargement of the skull base
sinus from the orbit to the torcular. B–E Angiography demonstrated a high-flow
shunting zone extending from the cavernous sinus region to the jugular bulb along
the superior petrosal sinus,lateral sinus, and sigmoid sinus.All possible feeders to the
region contributed to the supply of this shunting zone
3. An adult form of DAVS of the cavernous plexus (Fig. 7.4) or sigmoid sinus, in which the sinuses are normally small and sometimes partially
thrombosed and can be secondary to another local event (thrombosis).
The angiographic appearance of the three types is very different,as is their
clinical history. In certain cases, the significance of neurological symptoms
(cranial nerves) is different, although they may appear to look the same
(arterial steal, mechanical compression by venous ectasias, inflammatory
reaction around thrombosis,associated arteritis,venous congestion).
395Disease Groups
Fig. 7.4A–C. A 10-year-old child presented with ophthalmocavernous manifestations
with proptosis and cranial nerve palsy. A Arterial feeders arose from the internal
carotid and maxillary arteries. There was no evidence of cortical or inferior petrosal
sinus drainage.B,C Manual compression of the ophthalmic vein at the medial canthus
produced complete stagnation of the contrast medium within the sinus. Six months
later, complete occlusion was noted and the symptoms had disappeared; there was no
recurrence during 3 years of follow-up
7.3 Dural Sinus Malformations
This disease group includes (Scheme 7.1):
DSMs with giant pouches or lakes and mural AV shunting involving
the adjacent posterior sinuses. Partial thrombosis of the sinus may
occur and can also be observed in utero (Fig. 7.5).
DSMs of the jugular bulb, with otherwise normal sinuses, appear as a
sigmoid sinus-jugular bulb diaphragm and are associated with a
petromastoid-sigmoid sinus high-flow AVF that is usually of the
single-hole type.
7Dural Arteriovenous Shunts396
Scheme 7.1. Natural history
of dural sinus malformation
with dural arteriovenous (DAV)
shunts.ICP,intracranial
pressure. During the fetal
phase, dural sinus ballooning
occurs at 4–6months retrograde from the jugular bulb
to the superior sagittal sinus
3977.3 Dural Sinus Malformations
Fig. 7.5A–F. Legend see p. 398
7.3.1 DSM with Giant Pouches
7.3.1.1 Fetal and Postnatal Changes of Sinuses
“Somewhat uneven ballooning of the transverse sinuses” (described
by Masaki 1959, cited by Okudera et al. 1996) was observed in the
roentgenograms of the fetuses from the latter half of the 4th to the
7th month. After 20 weeks, the inner caliber of the transverse sinuses
gradually becomes even.From birth to the age of 1 year, the inner diameter of the transverse sinus decreases somewhat and after 1 year of age,the
sinus will have developed the adult configuration.
When we measured the inner diameters of the dural sinuses on
roentgenograms of the injected fetal brains, we found that the inner
diameters of the sigmoid sinuses remained relatively constant and small,
ranging in size from only 1 to 2 mm.Up to the 6th fetal month,the course
of the sinuses differs from that in the adult in following a gentle convex
curve medially,on the Towne view.After the 6th fetal month, the sigmoid
sinuses follow a gentle convex curve laterally.At this age,the course of the
sinuses approaches that of adults.The inner diameter of the jugular sinus
increases by only 1mm from the 3rd to the 7th fetal months and is
extremely small in caliber (1–2 mm on average). After birth, it rapidly
7Dural Arteriovenous Shunts398
Fig. 7.5A–H. Prenatal aspects on MRI. A, B Giant DSM, B, C in utero diagnosis of
epidural hematoma where it corresponds to an already partially thrombosed DSM.
E,F Similar case in a neonate;G,H partially thrombosed lesion in an infant.(Courtesy
of A. Goulao)
enlarges, forming a bulb-like configuration at 2 years; this is the formation of the (high) jugular bulb. During the period when the jugular sinus
is small and poorly developed, the transverse sinus is markedly enlarged
(ballooning), acting as a reservoir for the increased amount of stagnant
venous blood coming from (mostly the convexity of) the cerebrum and
cerebellum.Overflow of the venous blood flow from the transverse sinuses is manifested by the development, enlargement, and engorgement of
the emissary veins (the occipital sinuses, the marginal sinus, and the
internal vertebral and paravertebral venous plexuses). The formation of
the (high) jugular bulbs takes place after birth (clearly visible in the angiograms taken 2 years after birth) and is likely related to hemodynamic
factors, resulting from a change from the fetal lying down position to the
postnatal “erect posture”(Okudera et al.1996).
Thus the posterior sinus DSMs have been thought to correspond to an
abnormal perinatal persistence of sinus ballooning. However, this does not
explain why the so-called normal ballooning is not seen routinely in the
prenatal period in normal cases. Cases of DSM are by definition associated
with the uncontrolled development of posterior sinuses, including transverse, sigmoid sinus,and/or confluence of sinuses.Hence,DSM is a disease
of the sinus development instead of the embryological nondevelopment.
This accounts for the progression of the disease with sinus wall overgrowth, abnormal development of epidural confluence of venous spaces
leading to segmental giant lakes,followed by secondary thrombosis of the
spaces and subsequent remodeling if the venous drainage of the brain can
be rerouted. In some cases,the DSM ongoing increase in size is associated
with the appearance of hemorrhagic cavernomas (Mohamed et al. 2002)
(Fig. 7.6). Associations with sinus pericranii, ipsilateral lymphovenous
maxillofacial abnormalities, hemangiomas,or cleft palate testify for a more
complex disorder and suggest a cerebrofacial venous segmental distribution.No known hereditary vascular disease, such as HHT, is associated with
DSM. There is also no family history of DSM in our group of patients.
399Fetal and Postnatal Changes of Sinuses
Fig. 7.6. A MR at 5 months with a well-tolerated DSM. B, C In 7 months, explosive
progression with suspected dural sinus proliferation, venous infarction, and hemorrhagic de novo cavernomas
Associated slow-flow multiple AV shunts are consistently noted within
the wall of the malformed dural sinus,adding to the venous congestion of
the brain resulting from the frequently associated outlet restrictions,
since the brain has to drain through the diseased sinus. These additional
constraints for normal brain venous drainage persist until the cavernous
capture of the sylvian veins provides an alternate outlet toward the ophthalmic veins, inferior petrosal sinus into the jugular bulb,or directly into the pterygoid venous plexuses.Early and rapid spontaneous thrombosis within the DSM lake and postnatal dysmaturation of the jugular outlets further compromise cerebral venous drainage and subsequently lead
to acute hydrocephalus, venous infarction and lethal intraparenchymal
hemorrhage. As long as the venous outlets are patent, the clinical manifestations remain contained and restricted to related hydrodynamic
symptoms (macrocrania). The DSMs away from the torcular herophili
have a better chance of favorable outcome, as there will be at least one
normal sinus for the brain to drain. However, it is important to have the
ipsilateral cerebral hemisphere drain into an alternate pathway either by
cavernous capture or by a persistent medial occipital sinus bypassing the
thrombosed distal sigmoid sinus into the ipsilateral jugular vein or into
the contralateral sinus via the SSS. Drainage of the posterior fossa is
always difficult to demonstrate and is a significant risk if thrombosis of
the poorly anastomosing midline veins occurs. The presence of cerebellar DVAs will add further to that risk by making the system convergent,
which normally is divergent toward the petrous vein,the basal veins,and
the cervical spine veins.
Barbosa et al. (2003) reported on 30 patients with DSM seen in Bicêtre
Hospital from 1985 to July 2003 (Table 7.1). DSM accounted for 57.7%
of the DAVS in children. The three classic age groups are used to date
the clinical onset: neonates (from birth to 30 days), infants
(1–24 months) children (2–15years). The clinical and neurological
statuses of the patients were determined by pediatric neurologists
and assessment included the Brunet-Leizine and Denver neurocognitive tests.Infants were scored at admission and on follow-up using the
Bicêtre scoring system (See Chap. 2, this volume).A male dominance
was noted (2:1).The oldest patient at the time of diagnosis was 2 years
of age and the mean age was 5 months in this series. The mean age at
first consultation was 7 months for a maximum at 4years. Eight
(26.7%) patients were diagnosed prenatally during routine ultrasound; half had the torcula type of DSMs and for these the M:F ratio
was 1:1. Six patients (75.0%) had a favorable outcome and two
(25.0%) had an unfavorable outcome, one of which presented with
brain damage.
Early postnatal symptoms can be cardiac failure (usually mild and infrequent), coagulation disorders (consumption syndromes), moderately increased intracranial pressure (with irritability,macrocrania,neurocognitive delay, and seizures) occurring in young infants. The most frequent
clinical presentation (76.7%) was macrocrania. Seizures, psychomotor
delay,and intracranial hemorrhage (ICH) were noted in 23.3%.The latter
7Dural Arteriovenous Shunts400
was due to either venous infarcts or cavernomas in certain cases associated with underlying DVAs (Fig. 7.7).Brain damage was noted in 20% and
hydrocephalus in 24% (Table 7.1). The other clinical presentations were
cranial bruit, facial vein dilatation, and intracranial hypertension (ICT),
the latter being associated with macrocrania. Few cases were diagnosed
almost incidentally because of scalp hemangiomatous lesions or other
midline vascular abnormalities. Most of the lumps noted were located at
the vertex at the junction with the lambdoid suture,some of them representing a sinus pericranii equivalent (with a patent yet malformed sinus)
(Figs. 7.8–7.11).
MRI should be obtained whenever possible in these patients, as it
demonstrates best the dural sinus anomaly and its draining pattern, as
well as the status of the underlying brain. Other tools to analyze the
hemodynamics in these lesions have so far not provided additional information leading to a better understanding, nor have they helped in the
decision-making process.Angiography and embolization, if deemed necessary,should be performed during the same session, as most of the features encountered will be predictable. In neonates and infants in the absence of congestive cardiac failure (CCF), satisfactory imaging of the
cerebral drainage of the brain must be obtained by selectively injecting
the internal carotid artery rather than global injections that confuse
drainage of the lesion with drainage of the brain. Precise venous analysis
is more important than knowing the actual arterial supply to the mural
AVS. It d e t er mi n es t he importance, the speed, and the area where the
endovascular approach should be targeted as well as the timing of the
sessions.
401Fetal and Postnatal Changes of Sinuses
Ta ble 7.1. Clinical manifestationsa(Barbosa et al. 2003)
Clinical features %
Macrocrania 23/30 (76.7%)
Seizures 7/30 (23.3%)
Psychomotor delay 7/30 (23.3%)
Intracranial hemorrhage 8/30 (26.7%)
Brain damage 6/30 (20.0%)
Hydrocephalus 8/30 (26.7%)
Congestive cardiac failure 6/30 (20.0%)
Bruit cranial 5/30 (16.7%)
Facial veins dilatation 3/30 (10.0%)
Intracranial hypertension 3/30 (10.0%)
a
Children may have more than one.
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