Pediatric Vascular Neurosurgery Flashcards
Which one of the following pathologies is most likely to produce the ultrasound appearance seen below?
a. Band heterotopia
b. Germinal matrix hemorrhage
c. Hydrocephalus
d. Schizencephaly
e. Subependymal nodules
b. Germinal matrix hemorrhage
Papile’s classification:
Grade I—hemorrhage is confined to the germinal
matrix
Grade II—intraventricular hemorrhage without
ventricular dilatation
Grade III—intraventricular hemorrhage with
ventricular dilatation
Grade IV—intraventricular rupture and hemorrhage into the surrounding white matter
Which one of the following is most likely in a child with the below MRI appearance presenting with increasing head circumference
and shortness of breath?
a. Cavernous malformation
b. Developmental venous anomaly
c. Dural AV fistula
d. Tentorial AVM
e. Vein of galen malformation
e. Vein of galen malformation
Persistence of the single median prosencephalic
vein of Markowski into fetal life results in a dilated
venous sacin themidline, theVein ofGalenmalformation. Normal deep veins are absent and venous
drainage is routed through the median prosencephalic vein (or primitiveinternalcerebral vein).
Thistemporary vein drains the choroid plexus from
both sides almost between 5th and 10th week of
fetal life. With simultaneous development of basal
ganglia, thalamus, and cerebral vascularization,
paired internal cerebral veins appear to progressively annex the venous drainage of the midline structures. The falcine sinus becomes the normal outlet for the persistent median prosencephalic vein, with the straight sinus hypoplastic or stenosed.
Such persistence of fetal pattern maintains the fetal hemodynamics and as a result some dural sinuses may fail to develop altogether.
This 14-year-old presented with intraventricular hemorrhage. Which one of the following management options is likely to be discussed based on this right ICA angiogram?
a. Coil embolization
b. Extracranial-Intracranial Bypass
c. Intravenous antibiotics
d. Onyx embolization
e. Stereotactic radiosurgery
b. Extracranial-Intracranial Bypass
Adult moyamoya patients often present with hemorrhage, leading to rapid diagnosis. In contrast, children usually present with TIAs or strokes.
Other symptoms include seizures, headache, choreoatheform movements, ICH/ICH. Risk factors
include Asian origin, cranial radiotherapy, NF-1,
Down’s syndrome among others. Moyamoya
syndrome should be considered and diagnostic
evaluation begun in any child who presents with
symptoms of cerebral ischemia, especially if the
symptoms are precipitated by physical exertion,
hyperventilation, or crying. Hemorrhage from
moyamoya vessels can be readily diagnosed on
head CT, with the most common sites of hemorrhage being the basal ganglia, ventricular system, medial temporal lobes, and thalamus. Most suggestive of moyamoya on MRI is the finding of diminished flow voids in the internal carotid and middle and anterior cerebral arteries coupled with prominent collateral flow voids in the
basal ganglia and thalamus. The diagnosis of
moyamoya is said to require bilateral symmetrical
stenosis or occlusion of the terminal portion
of the intracranial carotid arteries as well as
the presence of dilated collateral vessels that
develop at the base of the brain producing the
classic “puff of smoke” appearance on angiography. External carotid imaging is essential to identify pre-existing collateral vessels, so that
surgery, if performed, will not disrupt them.
Aneurysms or arterio venous malformations
(AVMs), known to be associated with some cases
of moyamoya, can also be best detected by conventional angiography.
Choroidal vein of Galen malformations present most commonly as:
a. Congestive heart failure
b. Delayed developmental milestones
c. Focal neurological deficit
d. Increasing head circumference
e. Subarachnoid hemorrhage
a. Congestive heart failure
In the Lasjaunicas classification, VGMs are
divided into choroidal or mural types. In choroidal
586 PART VII PEDIATRIC NEUROSURGERY
type VGMs, the arteriovenous shunt is subarachnoid located in the tela choroidea along the cisterna velum interpositum with arterial feeders (choroidal arteries, thalamo-perforator arteries, and pericallosal artery) entering the anterior segment of the median prosencephalic vein. Multiple high-flow fistulas (large volume of shunt) results in cardiac failure in neonates. The aggressive volume overload results in cerebral ischemia and encephalomalacia.
In mural type VGMs, a single arteriovenous
fistula is situated in the inferolateral wall of the
median prosencephalic vein fed by collicular or
posterior choroidal arteries (i.e. fewer fistulas,
low-flow). They present later in infancy or early
childhood with failure to thrive and macrocephaly
due to hydrocephalus. Hydrocephalus develops
mainly due to impaired absorption because of
absence or stenosis of dural sinuses.
Which treatment would be preferred in a vein of Galen malformation patient with a extremely high flow shunt and in which perforating arteries are of small caliber?
a. Surgical excision
b. Transfemoral transarterial embolization
c. Transfemoral transvenous embolization
d. Transtorcula
e. VP shunting
c. Transfemoral transvenous embolization
Surgical treatment and natural history are associated with high morbidity and mortality. Adjuvant ventricular shunting is not necessary unless definitive endovascular treatment is unavailable immediately.
Emergency embolization is indicated in infants with refractory cardiac failure, acute or symptomatic hydrocephalus, rapid neurological deterioration orwhen parenchymal calcifications appear on followup scanning of brain. Neonates or infants having encephalomalacia or severe brain damage or severe parenchymal loss do not need any aggressive treatment because of poor clinical outcome in spite of successful closure of the shunt by embolization.
Transarterial embolization is employed when the
diagnostic angiogram demonstrates accessible feeding arterial branches from the choroidal and perforator arteries having sufficient caliber to permit navigation of themicrocatheters.Transvenous technique is particularly employed when the perforating
arteries are not of sufficient caliber to permit negotiation of the microcatheters. If the shunt is very large with extremely high flow the venous approach is preferred to avoid migration of the embolic material when delivered by the transarterial route. Occasionally it is necessary to use a combination of both techniques. In high flow choroidal malformations with no accessible femoral approach, occipital bone
over the torcular is penetrated with a large bore needle for catheterization of the varixin neonates.However it is necessary to make a burr-hole in older children. The goal of treatment is to reduce the volume load initially and attempt to finally obliterate the shunt completely. In the majority of infants and children, it becomes necessary to stage the embolization ranging from a few weeks to a few months based on the angioarchitecture and clinical
status. The follow-up endovascular approach is
based on the residual shunt and the architecture of the malformation. Occlusive venopathy is a wellknown delayed event causing progressive neurological deterioration. The acquired venopathy may be fatal. It is postulated that too long intervals between the embolization procedures would result in high
venous pressures in the dural sinuses and cortical
veins. The high flow venopathy is transmitted to
the medullary veins and cortical veins which would
result in progressive parenchymal calcifications and refractory seizures.
Wyburn-Mason syndrome is most accurately described by which one of the following statements?
a. Facial angioma and ipsilateral parietooccipital AVM
b. Multiple visceral, muscosal, and cerebral AVM
c. Optic tract glioma and midbrain AVM
d. Retinal angiomatosis, facial hemangioma, and midbrain AVM
e. Retinal angioma and posterior fossa hemangioblastoma
d. Retinal angiomatosis, facial hemangioma, and midbrain AVM
Which one of the following statements about pediatric intracranial aneurysms is NOT likely?
a. Infectious aneurysms are more commonin children than adults
b. Internal carotid bifurcation aneurysms are the commonest type
c. Posterior circulation aneurysms are more common that anterior circulation aneurysms
d. There is an association with coarctation ofthe aorta
e. They occur more commonly in males than females
c. Posterior circulation aneurysms are more common that anterior circulation aneurysms
The approach LEAST likely to be utilized during surgery for a dorsolateral brainstem cavernous malformation is:
a. Anterior petrosectomy
b. Retrosigmoid
c. Suboccipital
d. Supracerebellar infratentorial
e. Transcallosal
e. Transcallosal
A 9-year-old boy sustains a left sided penetrating brain injury secondary to air rifle accident. Initial CT head shows traumatic SAH and hemorrhagic contusion in the left temporal lobe. GCS recovers to 15 and he is discharged after 7 days. He is readmitted 5 days later with intermittent dysphasia and right facial weakness. Which one of the following surgically treatable conditions are you concerned about?
a. Enlarging aneurysm
b. Hydrocephalus
c. Maturation of hemorrhagic contusion
d. Meningitis
e. Vasospasm
a. Enlarging aneurysm
Traumatic aneurysms account for 14-39% of all
pediatric aneurysms. Children with neurological
deterioration after head injury should be suspected to have these lesions and investigated accordingly.
These aneurysms can result from direct trauma
(gunshot wounds, stab wounds, or surgical procedures). Indirect causes are trauma by falcine edge, sphenoid ridge, and sharp edge of fractured bone.
The patient can present with devastating hemorrhagein 50%. It could be SAH, subdural hematoma (SDH), ICH or extradural hematoma (EDH).
Aneurysm can bleed 5 h to 10 years after trauma
with a mean of 3 weeks. The patient can present
with irritability/unconsciousness or focal signs
due to enlargement of aneurysm. Infraclinoid aneurysm can present with diabetes insipidus, cranial nerve deficits, unilateral blindness, recurrent massive epistaxis, and features of carotid-cavernous fistula. Rupture carries mortality of 32-50%.
A 22month oldmale childwith a history of iron deficiency anemia developed progressive lethargy and vomiting over several days, culminating in flaccid quadriparesis. Brain MRI and MRV confirmed cerebral venous sinus thrombosis with subcortical white matter infarction. Lumbar puncture revealed elevated opening pressure, normal cerebrospinal fluid cell count, protein and glucose. Laboratory studies showed Hb 7.5 mg/dl with iron deficiency, and a positive lupus anticoagulant. The most appropriate management strategy is:
a. IV rehydration
b. IV rehydration and systemic heparin
c. IV rehydration and thrombolysis
d. IV rehydration and warfarinization
e. IV rehydration and venous stenting
b. IV rehydration and systemic heparin
Symptoms of cerebral venous sinus thrombosis are diverse and nonspecific, including most commonly the triad of headache, vomiting, and depressed mental status. Seizures are common, especially in neonates. Clinical signs include reduced GCS, papilledema, cranial nerve abnormalities (6th nerve palsy), hemiparesis, quadriparesis, ataxia, and hyper-reflexia. In neonatal CSVT, the most common signs and symptoms are lethargy, vomiting, a full fontanelle, and seizures. In newborns, acute systemic illness with dehydration and infection are the
most common predisposing conditions. Among
previously healthy children, acute head and neck
infections, dehydration, and iron deficiency anemia are common. Chronic diseases associated with childhood CSVT include inflammatory bowel disease, cancer, autoimmune disorders, and chronic liver or renal disease. Specific prothrombotic abnormalities that have been explored in pediatric CSVT include factor V Leiden and prothrombingenemutations, proteinC,S and antithrombin deficiencies, antiphospholipid antibodies, lipoprotein
(a), methyl tetrahydrofolate reductase mutations,
homocysteine, fibrinogen, plasminogen, factor
VIII, and heparin cofactor II. While CT imaging
is fast and convenient, this modality may miss the
diagnosis of CSVT in up to 40% of cases, and is best identified using MRI with MR venogram (MRV).
Ultrasound is convenient in infants with an open
fontanel but is less sensitive than either CT or
MRI. Primary treatment for CVST is anticoagulation with heparin. Additional therapies for CSVT
include thrombolysis or surgical thrombectomy,
but are associated with intracranial hemorrhage
hence usually usedwhen thereis a failure to respond to anticoagulation.
Which one of the following extracranial to intracranial bypass grafts is LEAST likely to be possible in children?
a. Encephaloduroarteriosynangiosis
b. Encephalomyoarteriosynangiosis
c. Encephalomyosynangiosis
d. Superficial temporal artery to MCA
e. Transposed temporalis muscle forms an anastomosis
d. Superficial temporal artery to MCA
In moyamoya disease, surgery is generally recommended for the treatment of patients with recurrent or progressive cerebral ischemic events and associated reduced cerebral perfusion reserve.
Many different operative techniques have been
described, all with the main goal of preventing further ischemic injury by increasing collateral
blood flow to hypoperfused areas of cortex, using
the external carotid circulation as a donor supply.
Direct anastomosis procedures, most commonly
superficial temporal artery (STA) to middle cerebral artery (MCA) bypasses, may achieve instant improvement in focal cerebral perfusion, but these procedures are often technically difficult
to perform because small pediatric patients often
do not have a large enough donor scalp artery or
recipient middle cerebral artery to allow for a
anastomosis large enough to supply a significant
amount of additional collateral blood supply. A
variety of indirect anastomotic procedures have
been described: encephaloduroarteriosynangiosis
(EDAS) whereby the STA is dissected free over a
course of several inches and then sutured to the
cut edges of the opened dura; encephalomyosynangiosis (EMS) in which the temporalis muscle is dissected and placed onto the surface of the brain to encourage collateral vessel development; and the combination of both, encephalomyoarteriosynangiosis (EMAS). Moyamoya patients are at particular risk of ischemic events in the perioperative period. Crying and hyperventilation, common occurrences in children at times during hospitalization, can lower PaCO2 and induce ischemia secondary to cerebral vasoconstriction. Any techniques to reduce pain—
including the use of perioperative sedation, painless wound dressing techniques, and absorbable wound suture closures—helped to reduce the incidence of strokes, TIAs, and length of stay in a recent study. A further perioperative consideration is the use of monitoring, such as intraoperative EEG or near-infrared spectroscopy, used to identify and ameliorate ischemic events detected while the patient is under general anesthesia.
Small, deep-seated pediatric arteriovenous malformations may be most appropriately treated with which one of the following?
a. Endovascular coil embolization
b. Fractionated stereotactic radiotherapy
c. Proton beam therapy
d. Stereotactic radiosurgery
e. Surgical excision
d. Stereotactic radiosurgery
