Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

FRCS Part 2 > Congenital anomalies > Flashcards

Congenital anomalies Flashcards

1
Q

What proportion of Chiari 1 malformations are associated with a syrinx?

A

30-70%(Guinto G et al. 2004 Part 1 Contemp Neurosurgery)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What proportion of patient with Chiari 1 and syrinx have hydrocephalus?

A

7-9%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What proportion of patients with Chiari 1 are asymptomatic?

A

15-30%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What abnormalities of the C-spine are associated with Chiari 1?

A

Anterior indentation at FM e.g. Basilar invagination

Klippel-Feil

Occipitalisation of atlas

Hypermobility of craniocervical junction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the commonest presenting symptom in Chiari 1 malformation?

A

Occipital headache (69%)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the most characteristic finding on eye examination in Chiari?

A

Downbeat nystagmus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the main signs associated with Chiari 1?

A

Foramen magnum compression syndrome (22%): ataxia, corticospinal and sensory deficits, cerebellar signs, lower cranial nerve palsies. 37% have severe H/A

Central cord syndrome (65%): dissociated sensory loss (loss of pain & temperature sensation with preserved touch & JPS), occasional segmental weakness, and long tract signs (syringomyelic syndrome). 11% have lower cranial nerve palsies

Cerebellar syndrome (11%): truncal and limb ataxia, nystagmus, dysarthria

Hydrocephalus and raised ICP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How much herniation is most often cited to diagnose Chiari 1?

A

5mm. Although this is not diagnostic nor essential.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is meant by Chiari zero malformation?

A

Patients with syringohydromyelia without hindbrain herniation that responded to p-fossa decompression

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Which patients are most likely to benefit from surgical intervention in Chiari 1?

A

Cerebellar syndrome responds well, as do headaches.

Symptoms lasting less than 2 years also do better than those that are >2 years

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What features are associated with Type 2 (Arnold)-Chiari malformation?

A

Myelomeningocoele (almost always)

Hydrocephalus

Beaking of tectum

Enlarged interthalamic adhesion (massa intemedia)

Low attachment of tent / torcula

Syringomyelia

Bony abnormalities - platybasia - Klippel-Feil - assimilation of atlas microgyria

Hypoplasia of falx

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the recommended indications for post fossa decompression in Chiari 2?

A

Neurogenic dysphagia

Stridor

Apneic spells

Always make sure patient has a working shunt first!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the commonest cause of mortality in Chiari 2?

A

Respiratory arrest.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the Lemire Classification?

A

Proposed classification system for neural tube defects - splitting them into pre neurulation (open) and post neurulation (closed) defects.

Non closure of neural tube e.g. craniorachischisis, anencephaly or myelomeningocoele in the spine.

Post neurulation (migration disorders) e.g. microcephaly, hydranencephaly, lissencephaly, porencephaly, diastematomyelia, diplomyelia, syringomyelia, DWM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the different forms of lissencephaly?

A

Agyria: completely smooth surface

Pachygyria: few broad and flat gyri with shallow sulci

Polymicrogyria: small gyri with shallow sulci. May be difficult to diagnose by MRI and may be confused with pachygyria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the different forms of migration defect?

A

Lissencephaly

Heterotopia - arrest of radial migration

Cortical dysplasia - a deep cleft that doesn’t communicate with the ventricle

Schizencephaly - cleft that communicates with the ventricle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the 2 different forms of schizencephaly?

A

Open lipped - communicates with cortical surface

Closed lipped - outpouching from the ependyma that does not communicate with cortical surface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How do you differentiate between schizencephaly and a porencephalic cyst?

A

InSchizencephaly the wall of the cyst is lined with cortical grey matter (usually abnormal, may have polymicrogyria), porencephalic cysts are lined by white matter.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What classically causes hydranencephaly?

A

Bilateral ICA infarcts (post neurulation defect)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How can you differentiated between hydranencphaly and hydrocephalus?

A

EEG - No cortical activity in hydranencephaly

MRI/CT/US - loss of anterior circulation but PCA distribution intact

Angiography - confirms no flow from ICAs bilaterally

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What causes cyclopsia?

A

severe holoprosencephaly - failure of the telencephalic vesicle to cleave into two hemispheres

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is holoprosencephaly associated with?

A

80% association with a trisomy (predominantly 13 and to a lesser extent trisomy 18)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What happens embryologically in holoprosencephaly?

A

Telencephalic vesicle fails to fully cleave into 2 hemispheres.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is MCAP?

A

megalencephaly-capillary malformation syndrome (MCAP): an overgrowth syndrome with megalencephaly (often with hydrocephalus, Chiari malformation, polymicrogyria and seizures) and capillary malformations in the skin (usually on the face)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What are the risk factors for the development of NTDs?

A

Folate deficiency, Cocaine, Heat in 1st trimester, Obesity, Valproic acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is a neuroenteric cyst?

A

CNS cyst lined by epithelium resembling that of the GI, or less often, respiratory tract.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Where in the CNS are you most likely to have a neuroenteric cyst?

A

Lower cervical/upper thoracic spine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is the mechanism of forming a neuroenteric cyst?

A

As a result of the persistence of the neuroenteric canal, a temporary duct between the notochord and the primitive gut (amniotic and yolk sacs) formed during week 3 of embryogenesis by the breakdown of the floor of the notochordal canal.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Where are intracranial neuroenteric cysts likely to be found?

A

P-fossa (CPA, Midline anterior to brainstem or cisterna magna)

Supratentorial locations are mainly suprasellar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Supratentorial neurenteric cysts, colloid cysts and Rathke’s may all arise from what?

A

Remnants of Seesel’s pouch - a transient endodermally derived diverticulum of the cranial end of the embryonic foregut

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

How would you investigate a patient with a Chiari 1 malformation?

A

MRI brain - tonisillar decent, brain stem compression, hydrocephalus, empty sella, associated conditions

MRI C- spine for syrinx and bony abn; CISS sequence for arachnoid web

CT skull base for posterior fossa volume, assimilation and skull base abn (platybasia etc)

Cine MRI - demonstrates CSF flow at FM

(CT myelogram if a contraindication to MRI)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What is the most commonly performed condition for Chiari 1?

A

Posterior fossa decompression through suboccipital craniectomy and C1 laminectomy

Size of craniectomy should be 3cm x 3cm. If too large causes cerebllar ptosis (sagging).

Y-shaped durotomy (note the torcula may be low!)

+/- dural expanstion graft

+/- tonsillar bipolar / adhesiolysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What are craniolacunia?

A

Rounded defects in the skull associated with sharp borders. Found in Chiari 2. Not associated with hydrocephalus.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What is the outcome of p-fossa decompession for Chiari?

A

70% near resolution of symptoms; 20% no difference

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What is Chiari 1.5?

A

Severe case of Chiari 1 with obex below the FM. Associated with platybasia.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What is Chiari 3?

A

Controversial if exists but is cerebellar herniation with occipital encephalocele.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What is Chiari 4?

A

Cerebellar hypoplasia with small p-fossa.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

How would you perform an FMD?

A

Informed Consent

GA / Prone / Mayfield pins / head elevated

Midline incision inion to C2

Suboccipital craniectomy 3x3 cm and C1 arch removal

USS for CSF flow.

If no flow then Y-shaped durotomy +/- expansion graft +/- adhesiolysis +/- tonsillar shrinkage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What happens if the suboccipital craniectomy is too large following FMD?

A

Cerebellar ptosis (sagging)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

What abnormality is commonly associated with a Schizencephaly?

A

Absent septum pellucidum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What the types of holoprocencephaly?

A

Lobar, semi lobar and alobar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What is microcephaly?

A

Head circumferences <2 S.D. from the mean

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What are the causes of microcephaly?

A
  1. Infections (TORCH / Zika etc)
  2. Malnutrition
  3. Toxins - maternal ETOH / Cocaine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

What serum marker suggests the presence of a neural tube defect?

A

AFP. If raised at 20 weeks suggests a 250x risk of NTD.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

What are the different types of holoprosencephaly?

A

Alobar - complete failure of separation with a single cerebrum

Semilobar - Frontal and parietal lobes fused but posterior interhemispheric fissure present

Lobar - Only frontal lobes fused

Syntelencephaly - Middle hemipshere fusion only

Arrhinencephaly - Absent olfactory bulbs, olfactory tracts and gyrus rectus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

In cerebral palsy, which part of the brain is most affected?

A

The periventricular WM as this is a watershed area in the neonatal period due to the increased metabolic demand of myelinating white matter. Causes periventricular leukomalacia.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

What genetic syndrome is associated with porencephalic cysts?

A

COL4A1 mutation. Note porencephalic cysts are lined by WM whilst schizencephaly is lined by GM.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

What are the most common locations for arachnoid cysts?

A

Middle fossa (50% in the sylvian fissure), CPA (10%), suprasellar (10%) and posterior fossa (10%).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

What are the imaging features of an arachnoid cyst?

A

Follows CSF on call sequences and associated with remodelling of the bone.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

How do you manage an incidental arachnoid cyst?

A

MRI+C and single further f/u study in 6 months to rule out increase in size.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

What is the aetiology of an arachnoid cyst?

A

Developmental splitting of the arachnoid membrane. Histologically are lined by meningothelial cells and are positive for EMA.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

What is the incidence of arachnoid cysts?

A

5 per 1000 at autopsy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

What condition are bilateral arachnoid cysts associated with?

A

Hurler’s syndrome (mucopolysaccaridosis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

What is the main differential diagnosis of an arachnoid cyst?

A

Epidermoid (shows restricted diffusion) Porencephalic cyst (lined by WM) Schizencephaly (lined by heterotopic GM)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

How do suprasellar arachnoid cysts present?

A

Endocrinopathy Developmental delay Hydrocephalus Visual loss Precocious puberty Bobble-head doll syndrome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

What is the classification for arachnoid cysts?

A

Galassi classification 1 - temporal pole and communicates with subarachnoid space during cisternography. 2 - anterior 1/2 of sylvian fissure with partial communication with subarachnoid space. 3 - Involves entire sylvian fissure and shows no communication with subarachnoid space.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

What are the treatment options for arachnoid cysts?

A
  1. needle aspiration / burr hole drainage (high recurrence rate) 2. Craniotomy, excision of cyst wall and fenestration into basal cisterns (higher morbidity and may need a VP shunt) 3. Endoscopic fenestration 4. Cyst shunting into the peritoneum (become shunt dependent)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

What valve should be used if shunting an arachnoid cyst?

A

Low pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

What are the surgical approaches for drainage of a suprasellar arachnoid cyst?

A

Transcallosal transventricular and transcortical transventricular

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

When do the fontanelles close?

A

Anterior fontanelle 2-3 years Mastoid fontanelle - 1 year Posterior fontanelle 2-3 months Sphenoid fontanelle 6 months

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

When is 90% of adult head size achieved?

A

1 year. Full size by age 7.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

When do mastoid air cells form?

A

6 years

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

What is primary craniosynostosis?

A

Prenatal deformity caused by suture fusion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

What is secondary craniosynostosis?

A

Metabolic (Rickets), Drugs (AEDs), Haemotological (Sickle cell / thalassemia) and structural (microcephaly)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

What are the surgical indications for multi-suture craniosynostosis?

A

Impedes brain growth and for raised ICP. Note 10% of single suture craniosynostosis also develop raised ICP.

66
Q

Which craniosynostosis may result in amblyopia?

A

Coronal

67
Q

What do you feel when palpating a craniosynostosis?

A

Ridge (except lambdoid which may be a trough)

68
Q

What does metopic synostosis cause?

A

Trigonocephaly

69
Q

What does single coronal suture synostosis cause?

A

Anterior plagiocephaly

70
Q

What does bilateral coronal suture synostosis cause?

A

Brachycephaly

71
Q

What does sagittal suture synostosis cause?

A

Scaphocephaly

72
Q

How do you differentiate positional plagiocephaly from unilateral lamboid suture synostosis?

A

Position of the ear is pulled back with unilateral lamboid suture synostosis and the skull forms a trapezoid shape compared to a parallelogram that is seen with positional plagiocephaly

73
Q

What is the most common single suture synostosis?

A

Scaphocephaly (sagittal suture synostosis) - 80% occur in males

74
Q

How is Scaphocephaly (sagittal suture synostosis) treated?

A

Strip craniectomy with excision of the sagittal suture

75
Q

How can Crouzon’s and Apert’s syndromes be distinguished?

A

Both cause coronal suture synostosis which is more common in females. Crouzon’s is associated with midface hypoplasia whilst Apert’s is associated with syndactyly.

76
Q

What eye sign is seen with unilateral coronal suture synostosis?

A

Harlequin eye sign

77
Q

How is coronal suture synostosis treated?

A

Suturectomy or frontal craniotomy with orbital advancement

78
Q

What chromosome abnormality is associated with metopic synostosis?

A

Ch19q

79
Q

What investigations may be performed for synostosis?

A

Xray, CT and Tc bone scans

80
Q

What is the management of positional plagiocephaly?

A

Repositioning therapies Surgery in 20% of cases that are refractory to repositioning therapies There is no evidence for helmets but some use them

81
Q

What mutation is found with Crouzon’s and Apert’s?

A

FGFR (autosomal dominant)

82
Q

What is the cause of a polypoid mass in the nose of an newborn?

A

Encephaloceole

83
Q

How are encephalocoeles classified?

A

Suwanwela and Sunwanela classification into: Occipital, cranial vault, frontoethmoidal, basal and posterior fossa.

84
Q

What % of infants with encephaloceles develop normally?

A

<5%. The more neural tissue the worse the outcome.

85
Q

What is Dandy Walker malformation?

A

An enlarged posterior fossa with cerebellar hypoplasia / agenesis and cystic dilatation of the 4th ventricle (also has an enlarged cisterna magna).

86
Q

What is a Dandy Walker variant?

A

When not all 3 factors for Dandy walker malformation are present e.g. posterior fossa may not be enlarged but there is dilatation of the 4th ventricle and vermian agenesis for example.

87
Q

What is a persistent blake’s pouch cyst?

A

Blake’s pouch is a transient protrusion from the 4th ventricle through the foramen of magendie that usually regresses by 4 months gestation. The torcula is in the correct place. If persistent results in an imperforate foramen of magendie.

89
Q

What is the differential for a posterior fossa cyst?

A

Dandy-walker malformation

Dandy-walker variant

Persistent blake’s pouch cyst

Arachnoid cyst

Mega cisterna magna

Joubert’s syndrome due to underdevelopment of the vermis

90
Q

How can Dandy Walker malformation be distinguished from other posterior fossa cysts?

A

DWM has true vermian agenesis. The others just compress the vermis.

Choroid plexus is absent

91
Q

What is PHACES syndrome?

A

Posterior fossa malformation

Haemangioma (craniofacial)

Arterial anomalies of the head and neck

Coarctation of the aorta / cardiac defects

Eye anomalies

Sternal cleft

92
Q

What syndrome can Dandy walker malformations be associated with?

A

PHACES

93
Q

What is the treatment for Dandy Walker Malformation?

A

Treatment of hydrocephalus through shunting of the posterior fossa cyst afte ruling out aqueductal stenosis

(not the lateral ventricles due to risk of upward herniation)

ETV can also be performed

94
Q

What conditions are associated with aqueductal stenosis?

A

Chiari malformation and neurofibromatosis

95
Q

What visual abnormalities are associated with papilloedema?

A

Visual obscurations and lack of acuity

Peripheral field cuts

Increased blind spot

96
Q

Why is contrast given when investigating aqueductal stenosis?

A

To rule out tumour

97
Q

What are the treatments for Aqueductal stenosis?

A
  1. ETV
  2. VP shunt
  3. Tokildsen shunt (lateral ventricle to cisterna magna)
98
Q

What causes callosal agenesis?

A

Failure of commissuration of the prosencephalon which occurs ~8 weeks gestation.

99
Q

What is indicated by absence of the anterior CC but presence of the posterior CC?

A

Holoprosencephaly

100
Q

What is Aicardi syndrome?

A

Agenesis of the CC

Seizures

Retardation

Retinal pigmentation

101
Q

What conditions are associated with absence of the septum pellucidum?

A

Holoprosencephaly

Schizencephaly

Agenesis of the CC

CM type 2

Septo-optic dysplasia

Chronic hydrocephalus

102
Q

Where are intracranial lipomas most commonly found?

A

Corpus callosum (associated with callosal agenesis)

103
Q

What is the differential diagnosis of an intracranial lipoma?

A

Dermoid cyst, teratoma and germioma

104
Q

What is the difference between a dermoid and a teratoma?

A

Dermoids are ectodermal in origin (predominantly skin and hair)

Teratomas are mesoderm and endoderm (predominantly fat, muscle and bone).

105
Q

Where do hypothalamic hamartomas arise from?

A

The tuber cinereum

106
Q

What are sessile hypothalamic hamartomas?

A

Remain within the hypothalamus (oppose to pedunculated ones which are parahypothalamic)

107
Q

How to Hypothalamic Harmatomas present?

A

Precocious puberty, gelastic seziures and developmental delay

108
Q

How are Hypothalamic Hamartomas treated?

A

GnRH analogues for precocious puberty

For pedunculated HH, open approaches through pterional craniotomy or LITT

109
Q

What syndrome is associated with HH?

A

Pallister-Hall syndrome

110
Q

What are the imaging features of HH?

A

Iso on T1 and T2 with no contrast enhancement

Lesion arising from the floor of the third ventricle

111
Q

What is the typical location of a spinal arachnoid cyst?

A

Almost always dorsal. If ventral then think of neurenteric cyst or arachnoiditis

112
Q

What are the treatment options for arachnoid cysts?

A

Drainage, resection, fenestration and shunting (cysto-peritoneal)

113
Q

What is spina bifida occulta?

A

Congenital absence of the spinous process +/- other posterior elements with no exposure of the meninges or neural tissue. Incidence = 10%

114
Q

What is a meningocele?

A

Herniation of the meninges but not neural diffuse through spinal defect

115
Q

What is a myelomeningocele?

A

Herniation of the meninges and neural tissue through a spinal defect

116
Q

When does the cranial neuropore close?

A

Day 25

117
Q

When does the caudal neuropore close?

A

Day 28

118
Q

What is the incidence of spina bifida (myelomeningocele)?

A

1 in 1,000

119
Q

What lowers the incidence of myelomeningocele?

A

Folate supplementation

120
Q

What is the incidence of hydrocephalus with myelomeningocele?

A

80%. Note closure of the defect converts a latent hydrocephalus to a active one as there is no other route for CSF egress

121
Q

What allergy is commonly found in patients with myelomeningocele?

A

Latex allergy in 75%

122
Q

What does the MOMS trial show?

A

RCT of post-natal vers Fetal closure of myelomeningocele. Fetal closure reduces the incidence of hydrocephalus from 82% to 40% and type 2 chiari. Improved mental development and motor function at 30 months with fetal repair akin to a neurological level 2 levels lower than would be seen with post-natal repair but higher risk of preterm delivery and uterine dehiscence.

124
Q

How do you manage a fetus with spina bifida?

A

Measure size of defect If ruptured then start abx Cover with sterile dressing to prevent dessication Lie patient on stomach to prevent pressure on MM Closure within 24 hours

125
Q

Following surgical closure of a myelomeningocele what are good prognostic signs?

A

Spontaneous movement of the LLs No chiari 2 (if present check for stridor and apnoeas) No HCP (do head USS)

126
Q

Why do patients with sacral myelomeningocele get clawing of the feet?

A

As the foot intrinsics are supplied by S1-3

127
Q

What other anomalies are associated with myelomeningoceles?

A

Pulmonary immaturity Bladder dysfunction (need catheterization) Scoliosis Hip and knee deformities

128
Q

What are the key steps of a myelomeningocele repair?

A
  1. Free the placode from the dura to avoid tethering and release the filum terminale 2. Re-approximate the placode by suturing the pia 3. Water-tight dural closure 4. Facia and skin closure
129
Q

What happens if there are any epithelial remnants on the placode?

A

Dermoid cysts arise

130
Q

What is the cause of a CSF leak after a myelomeningocele repair?

A

Hydrocephalus

131
Q

What is the most important factor to rule out when a patient with a myelomeningocele deteriorates?

A

Shunt malfunction

132
Q

What is the benefit of detethering the cord during myelomeningocele repair?

A

May improve scoliosis

133
Q

What is the main cause of mortality in patients with myelomeningocele?

A

Complications associated with the Chiari 2 malformation - aspiration / respiratory arrest etc and shunt failure

134
Q

What are the 3 important spinal dysraphisms associated with lipoma?

A

Intradural lipoma Lipomyelomeningocele Lipoma of the filum terminale These all occur due to early (premature) dysjunction

135
Q

What is the embryological cause of myelomeningoceles?

A

Non-dysjunction (which is part of primary neurulation)

136
Q

What proportion of myelomeningocele patients become ambulatory?

A

50-80% with bracing

137
Q

What are the cutaneous stigmata associated with spina bifida?

A

Fatty pads, port-wine stains, hair tuft, dermal sinus opening or skin appendages

138
Q

What embyrological process causes a dermal sinus?

A

Failure of dysjunction

139
Q

What types of cysts are associated with dermal sinuses?

A

Epidermoid or Dermoid depending on the contents

140
Q

What is the difference between an epidermoid and a dermoid?

A

Epidermoids contain epithelium, Dermoids contain skin and hair.

141
Q

When should dermal sinuses be excised surgically?

A

When above the lumbosacral region; Coccyx sinuses do not need to be treated unless infections occur.

142
Q

What is the management of dermal sinuses?

A

Surgical exploration and full excision prior to neurological deficit or infection (as they cause recurrent meningitis)

143
Q

What is Klippel-Feil syndrome?

A

Congenital fusion of two or more cervical vertebrae

144
Q

What causes Klippel-Feil syndrome?

A

Failure of the normal segmentation of cervical somites between weeks 3-8.

145
Q

What is the clinical triad of Klippel-Feil syndrome?

A
  1. Low posterior hair line 2. Short neck 3. Limited neck movement (affects rotation more)
146
Q

What is Sprengel’s deformity?

A

Raised scapula due to failure to descend to normal position (assoc with Klippel-Feil)

147
Q

What is tethered cord syndrome?

A

Abnormally low conus (below L2) - assoc with short thickened filum (>2 mm) or intradural lipoma

148
Q

What are the causes of worsening symptoms with MM?

A

Shunt faliure! Consider tethered cord if painful and syringomyelia if painless

149
Q

How do tethered cords present?

A

May be asymptomatic, pain, foot deformities, scoliosis, leg weakness, urological symptoms and cutaneous stigmata

150
Q

How can the filum be differentiated from a nerve root?

A

Tortuous vessel on the surface of the filum and white appearance.

151
Q

What are the types of spilt cord malformation?

A

Type 1 - two hemicords, each with its own central canal, pia and dura. Have a bony septum. Treated by untethering the cord after removing any bony septums and reconstituting a single tube. Type 2 - two hemicords within a single dural tube separated by a fibrous medial septum

152
Q

What is the Cannon’s classification for congenital nerve root anomalies?

A

1 - conjoined roots (2 nerve roots within a common dural sheath) 2 - 2 nerve roots exiting through the same foramen 3 - Adjacent nerve roots are separated by an anastomosis

153
Q

What is Ecchordosis physaliphora?

A

Notochordal remnant found in 1-2% of autopsies in the retroclival region. Focal gelatinous mass. Indistinguiable from chrodomas.

154
Q

How would you counsel a mother with an antenatal diagnosis of myelomeningocele?

A

The mother should be informed of the implications of the diagnosis and immediate and long-term consequences. These include:

The mode of delivery (C-section > vaginal)

Uncertain nature of the deficit

Early closure required within 12-24 hours - risk of CSF leak, meningitis 5%, wound breakdown 10% and dermal inclusion cyst 1%.

The potential need for VP shunt (80%)

Association with Chiari, syrinx, scoliosis, lower limb deformities and bowel/bladder dysfunction

Association with other intracranial abnormalities e.g. callosal agensis

155
Q

How do you nurse a patient with a myelomeningocele?

A

Take a picture, nurse prone and cover the defect with moist sterile gauze and wrap in cling film

Start IV antibiotics

156
Q

If a child is born with a myelomeningocele, what is the risk for future pregnancies?

A

The genetic component of the disease accounts for 10% risk for future pregnancies. Folic acid supplementation reduces the subsequent risk.

157
Q

What are the causes of delayed deterioration following myelomeningocele repair?

A

Hydrocephalus / Shunt malfunction

Tethered cord

Chiari malformation

Syrinx

158
Q

What investigations of bladder function can you perform in children?

A

Urodynamics (measures flow rate and bladder residual)

Micturating cystourethrogram

Sphincter EMG

159
Q

What does a high arched foot (pes cavus) suggest?

A

Weakness of the intrinsic muscles of the foot which are supplied by S1/2 roots. Chronic denervation results in pes cavus.

160
Q

What do the combination of pes cavus and sphincter disturbance suggest?

A

Dysfunction of the sacral nerve roots (S2)

161
Q

What embryological failure results in myelomeningocele?

A

Failure of dysjunction

162
Q

What is an LDM?

A

Limited dorsal myeloschisis, characterised by a fibroneural stalk. If the stalk is mainly fibrous then it is a dermal sinus tract. Note myeloschisis means a flat placode that failures to form a tube.

163
Q

What surgery is performed for tethered cord with progressive weakness?

A

Spinal cord untethering and release of the filum terminale (which connects the conus to the sacral haitus). Tethering symptoms are unlikely to get worse after the person stops growing.

FRCS Part 2 (17 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions