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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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71Hydrodynamic Disorders
Fig. 2.26A–D. A male infant presented at the age of 6 months with epistaxis. Macrocrania was noted. He was referred at the age of 2 years with left-sided exophthalmos,
intense facial collateral circulation and no neurocognitive delay. On MRI there is evidence of a small vein of Galen aneurysmal malformation with rerouting of the venous
blood flow through the left superior petrosal sinus,cavernous sinus,and orbital vein.
The tonsillar prolapse points to the posterior fossa hydrovenous disorders
2Introduction and General Comments Regarding Pediatric Intracranial Arteriovenous Shunts72
Fig. 2.27A,B. A young girl
was referred to us at the age
of 5 years with significant
macrocrania already shunted.
A MRI demonstrated tonsillar
prolapse. B Following embolization, there is almost complete
occlusion of the vein of Galen
aneurysmal malformation with
shrinkage of the ectatic pouch.
Also note the hypersignal and
the thickening of the cranial
vault bones
Fig. 2.28A–C. A young adult male had had a torcular dural sinus malformation with
macrocrania since infancy. After 10 years, the lesion is partially thrombosed; note a
tonsillar prolapse, upper cervical spinal cord cavitation,and bone hypertrophy.Solid
arrows,arterial supply (A), venous drainage (open arrows) (B), and partially throm-
bosed torcular herophili (arrows) (C). (From Apsimon et al. 1993)
2.5.3 Melting-Brain Syndrome
Melting-brain syndrome consists in the rapid destruction of the brain, usually the white matter, with secondary ventricular enlargement. This phenomena is associated with severe neurological manifestations and no signs
of increased intracranial pressure,although they are usually present before
the morphological damage is seen. When brain suffering leads to trophic
changes, these are usually bilateral and symmetrical; they correspond to a
regional decrease in the cerebral blood flow caused by retrograde venous
hyperpressure,leading to hydrovenous dysfunction.Arterial steal is not present or accessory in this syndrome.The local atrophy around a PAVM can be
a focal expression of this phenomenon (Fig. 2.29). These findings are never
encountered in adults. It illustrates the role played by the subpial and
medullary veins in the maintenance and development of the white matter. It
may not be seen in lesions that open without restriction into a subarachnoid
venous outlet. We have observed it in neonates and young infants (up to
3months ofage) in all types of AV shunts:VGA,DSM, and PAVM. However,
while the mechanism is the same,each lesion creates the condition (regional hydrovenous dysfunction) in a different fashion (Table2.3).
73Melting-Brain Syndrome
Fig. 2.29A,B. A 10-year-old
girl presented a cerebellar
arteriovenous malformation
revealed by a generalized
seizure. Note the cerebellar
atrophydetected at MRI
examination. Clinically,she
has mild cerebellar ataxia
Ta ble 2.3. Melting-brain syndrome
Etiology Prenatal Neonatal Early infancy Late infancy
VGAM ++
a
+++ – +
DAVS + ++
b
+++ –
PAVM – 0 + +
c
+++
Cumulative negative factors include the following: no cavernous sinus opening of
cerebral venous drainage; pial vein congestion, or decreased venous flow with
hydrodynamic disorders; progressive sinus stenosis and secondary thrombosis;
venodural sinus junction incompetence with or without raised intrasinusal pressure
and pial vein reflux.
VGAM, vein of Galen aneurysmal malformation; DAVS, dural arteriovenous shunt;
PAVM, pial arteriovenous malformation; +++, very frequent; ++, frequent; +,
possible; –, not seen.
a
Systemic mechanism.
b
Dural malformative mechanism.
c
Hydrovenous congestive mechanism.
2Introduction and General Comments Regarding Pediatric Intracranial Arteriovenous Shunts74
Fig. 2.30A–C. Legend see p. 75
75Melting-Brain Syndrome
Fig. 2.30A–H. A young boy
presented at the age of
4months with macrocrania.
A–C At the age of 6 months,
initial MRI (not shown) and
angiogram confirmed the diagnosis of a small vermian arteriovenous malformation; retrograde congestion of the torcular
in relation to bilateral stenosis
of jugular bulbs had already
occurred.The venous drainage
of the carotid injection demonstrates the difficulty of drainage
associated with restriction of
the outlets.One month later,
the child became comatose.
D, E Angiography demonstrated
a complete occlusion of the
jugular bulbs. F–H Major
melting-brain syndrome is seen
in the frontal region.Note in
this particular patient the small
size of the lesion and the
absence of arterial steal phenomenon.The child died soon
after these examinations.
(Courtesy of R. Piske)
▲
In VGAM, the damage starts during fetal development in relation to
the systemic failure; the combination of venous and arterial disorders
may accelerate the melting phenomena.In DSM,the malformation of the
sinus and the early occlusion of the few venous outlets available rapidly
precipitate the central venous drainage. In CAVM, the phenomenon occurs late (at 7–8months of age) and progressive spontaneous thrombosis
of the venous drainage has to occur to provoke the syndrome in the absence of patent alternate pathways (Fig. 2.30).
This mechanism is progressive and once it starts, it develops fairly
rapidly, although it is slow enough to result in a loss of substance rather
than a hemorrhagic infarct, which supports the role played by water in
the maintenance of brain tissue.In some cases, following limited hemorrhagic infarct, progressive melting is noted despite treatment (Fig. 2.21).
In this situation, the venous congestion has been partially or totally relieved, but the insult has remained irreversible.If the insult is even slower, calcifications will take place with a moderate tissue loss until a new
equilibrium is found between the remaining brain substance, the available nutrition, and venous outflow. The different outcome in diffuse melting-brain syndrome and the regional type and local atrophy encountered
in young children depends on the role played by subpial and subarachnoid venous drainage (Table 2.4). Subpial veins actually communicate
with subependymal veins via the medullary veins located in the Virchow
Robin spaces and are therefore capable of interfering with the water (intrinsic) equilibrium.In contrast,the subarachnoid veins directly travel in
the pericerebral spaces with little impact on the intrinsic water physiology as long as the dural sinuses are sufficiently patent.Thus two high-flow
lesions both apparently located on the surface of the brain may have different effects on the underlying cerebral tissue, depending on whether
they open directly into subpial or subarachnoid outlets almost independently of the flow they carry.
In neonates and infants, this equilibrium represents a highly sensitive
system. Any shift in the hydrodynamics will have a regional effect, and
any decrease in the ventriculocortical gradient will alter the growth of the
corticosubcortical substance. Water retention is often noted before the
obvious destructive phase of the brain: most melting-brain syndromes
provoke macrocrania before the head circumference curve falls below
normal values.
The fear of being confronted with such a syndrome should prompt
therapeutic attempts, provided that one is able to identify irreversible
damage and predict the degree of residual disability if treatment succeeds in limiting damage (Fig. 2.22).Appropriate knowledge and understanding of the natural history and pathophysiology of VGAM,DSM, and
CAVM disorders in neonates and infants is mandatory. The so-called
melting of brain tissue may be an apoptotic phenomenon triggered by
the hydrovenous disorders described above.
2Introduction and General Comments Regarding Pediatric Intracranial Arteriovenous Shunts76
Intracranial AV Shunt
in Children
Cerebral Manifestations
Veno us congestion
Veno us ischemia
Haemorrhagic infarct
Melting brain syndrome
Arterial steal
Intracranial AV Shunt
in Children
Neurological Symptoms
Mental retardation
Epilepsy
Deficit
Hypertony
and abnormal movements
Headaches
2.6 Clinical Evaluation Scores
With the tendency to use sophisticated tools to approach brain function
in children, combined with our lack of knowledge on the physiology and
plasticity of the brain at this age, clinical evaluation represents one of the
most important and difficult aspects of management in children.
Perinatal and early childhood examinations are challenging for neurologists and even more so for neuroradiologists. With the quality of
images obtained,a strict morphological result,elegantly photographed, is
often felt to be eloquent enough. However, this satisfaction cannot be
complete without appropriate clinical assessment and follow-up. This is
the primary therapeutic goal and challenge for us: a child growing normally is more important than one that is morphologically cured but disabled.
With the increasing role of neurological interventions in children and
the full-time involvement of pediatric neurosurgeons,attention has been
directed toward the peritherapeutic clinical follow-up,with an attempt to
use reliable scores and evaluation scales. More recently, we have been
contributing to pretherapeutic evaluation in neonates and follow-up in
these children in order to anticipate early delays and identify reversible
situations. This subsequently led us to the therapeutic window concept,
in which early management is a complex technical challenge with few
chances of a good clinical outcome (see Chap. 3, this volume), and late
management, although easier, will not be able to correct irreversible
functional damage (see Chap. 4,this volume).
Three aspects of the classical clinical references available illustrate the
difficulties we face in trying to compare our individual results:
1. The adult scores do not apply: Glasgow (initial and outcome) and
Karnowski (Tables 2.5–2.7).
2. Pediatric scores are usually simple but do not take into consideration
the vascular nature of the lesion,but rather the static analysis of a trau-
matic insult to an otherwise normal brain (Tables 2.8, 2.9; Seshia
1988;Yager 1990; Reilly-Simpson 1982,1988; Raimondi 1984).
77Clinical Evaluation Scores
Ta ble 2.4. Systemic hydrovenous manifestations in arteriovenous shunts and their
specific main venous drainage
Manifestation Drainage Cardiac failure Melting-brain
syndrome
VGAM Choroidal vein + +
AVF pial Subarachnoid vein + –
AV M subpial Subpial vein ± ++
Nidus or fistula
Subpial AVF Subarachnoid vein ± –
Epidural AVF Epidural venous system ± ±
VGAM, vein of Galen aneurysmal malformation; AV, ateriovenous; AVF AV, fistula;
AVM, AV malformation.
2Introduction and General Comments Regarding Pediatric Intracranial Arteriovenous Shunts78
Ta ble 2.5. Adult Glasgow Coma Scale
Score Eye opening Verbal response Motor response
6– – Carrying out commands
5– Oriented Localization of pain
4Spontaneous Confused conversation Withdrawal from pain
3To speech Inappropriate words Abnormal flexion
2To pain Incomprehensible words Extensor response
1None None None
Wo rld Federation of Neurological Societies grading is as follows: grade I, for a total
Glasgow score of 15; grade II,for a total Glasgow score of 13/14 without deficit; grade
III, for a total Glasgow score of 13/14 with deficit; grade IV, a Glasgow score of 7–12;
grade V,a total Glasgow score of 3–6.
Ta ble 2.6. Adult Glasgow Outcome Score
Score Outcome
5Good recovery; full independent life with minimal neurological deficit
4Moderately disabled;neurological or intellectual impairment,but
independent
3Severely disabled; conscious, but totally dependent on others
2Vegetative
1 Death
Ta ble 2.7. Karnovsky Scale
Score Patient’s condition
100 Normal, no complaints
90 Normal activity,minor signs
80 Normal activity with effort
70 Can care for self, but unable to carry out normal activities or do active work
60 Requires occasional assistance
50 Requires considerable assistance and frequent medical care
40 Disabled; requires special care and assistance
30 Severely disabled; hospitalization necessary
20 Very sick; hospitalization necessary
10 Moribund
0 Dead
79Clinical Evaluation Scores
Ta ble 2.8. Modified Adelaide Pediatric Glasgow Coma Scale (Simpson et al.1991)
Score Eye opening Verbal response Motor response
6– – Carrying out of commands
5– Oriented (smiles) Localization of pain
4Spontaneous Words (can be consoled Withdrawal from pain
when crying)
3To speech Vocal sounds (incon- Abnormal flexion to pain
sistent,consolable) (decortication)
2To pain Cries (not consolable, Extension to pain
irritable, restless) (decerebration)
1None None None
Modified from the Children’s Coma Scale (CCS), derived from the Glasgow Comas
Scale by Hahn (1988).
Ta ble 2.9. Pediatric milestones (Adelaide Pediatric Coma Scale; Simpson et al.1991)
Age Response
Motor responses
a
BirthSpontaneous and reflex flexion and extension
12 weeks Selective movement of limb when pricked
20 weeks Voluntary grasp
26 weeks Voluntary transfer
32 weeks Gazes directly at limb when pricked
48 weeks Gives toy to examiner
52 weeks Localizes prick exactly
18 months Obeys simple orders
2years Points to parts of the body
Ve r b al responses
b
Birth Cries
8weeks Vocalizes (chiefly vowels)
16 weeks Laughs, uses consonants
28 weeks Syllables (ba, da,ka,mu)
48 weeks One-word utterances with meaning
52 weeks Two- and three-word utterances with meaning
18 months Jargon,many intelligible words
24 months Spontaneous two- or three-word sentences
3years Asks questions,uses pronouns
4years Talks fluently, of ten fabricates or fantasizes
5years Answers age questions correctly, knows name,
draws man
a
Motor coma norms: flexion, 0–26 weeks; localization or pain, 6 months to 2 years;
obeys orders after 2 years.
b
Ve rbal coma norms: cries, 0–26weeks; vocal sounds, 26–52 weeks; words,
1–5 years; oriented verbal response, after 5years.
3. Neonatal neurological assessment is a particularly difficult issue, with
little attention paid to possible systemic manifestations (Duncan et al.
1981; Table 2.10).We therefore have had to develop several scores and
have combined these in accordance with our personal experience since
1982:
– A neonatal score,particularly oriented to choose the timing for em-
bolization and predict the neurological outcome in severe systemic
disorders.Most of these neonates have a limited neurological examination (Table2.11).
– An initial and outcome score for infants and older children, intro-
ducing developmental delays with focal neurological deficits and
systemic cardiac manifestations. This gross categorization attempts
to introduce the quality of a cognitive result, despite the neurologically normal examinations often reported (Table 2.12).
– The Denver and Brunet Leisine test for neurocognitive evaluation
was chosen by our pediatric neurology group, despite its imperfection,for its ease of use and acceptable quantification regardless of
cultural differences (Schemes2.13, 2.14).
We have found these tools useful, not to give universal rules but rather to
compare and rationalize our decisions over time. We have been able to
assess the stability and accuracy of the criteria chosen to establish the
therapeutic objectives.(Scheme 2.15; Fig. 2.30)
Our experience has shown that these scores do not seem to apply only
to Caucasians, but can be applied in many different cultures, and they
appear to confirm that cultural differences in terms of life, death, and
handicap are smaller among children than adults.
2Introduction and General Comments Regarding Pediatric Intracranial Arteriovenous Shunts80
Ta b l e 2 .10. Neonatal Coma Scale (Duncan 1981)
Score Response to bell Response to light Motor response
6– – Spontaneous periods of activity
alternating with sleep
5Facial and extremity movements – Occasional spontaneous movements
4Grimace,blink Blink, facial/extremity Extremity movements
a
3Increase in righting reaction Blink Grimace/facial movements
a
2Seizures/extensor posturing Seizures/extensor posturing Seizures/extensor posturing
a
1No response No response No response
a
a
Response to sternal rub.
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