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Plastic Surgery - Craniofacial > Craniosynostosis > Flashcards

Craniosynostosis Flashcards

1
Q

Incidence of craniosynostosis

A

1:2500 live births

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2
Q

Normal cranial growth

A

Growth responds to increasing brain and CSF, brain triples by 1 year, quadruples by 2 years, 85% of adult growth by 3, near adult size ages 6-10

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3
Q

Two mechanisms of normal skull growth

A

Sutural - perpendicular to sutures

Appositional - bone resorption on the inner surface and deposition on the outer surface

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4
Q

Normal Suture Fusion

A 
Metopic = 6-9 mo
Sagittal = 22 yrs
Coronal = 24 years
Lambdoidal = 26 years
Squamous = 35 years
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5
Q

Normal fontanelle closure

A 
Posterior = 6-9 mo
Anterior = 9-12 mo
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6
Q

Virchow’s Law

A

premature suture fusion results in cranial growth PARALLEL to sutures

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7
Q

Cranial base theory of suture closure

A

synostoses result from abnormal tension exerted by cranial base through the dura; theory does not account for isolated synostoses

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8
Q

Intrinsic suture biology theory of suture closure

A

Synostoses result from the osteoinductive properties of dura mater, which contains osteoblast-like cells

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9
Q

Extrinsic factor theory of suture closure

A

Synostoses result from extrinsic forces or systemic disease; in utero compression or ischemic event, hydrocephalus decompression, abnormal brain growth (microcephaly), systemic pathology (Rickets or hypothyroidism)

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10
Q

Genetics of crainiosynostosis

A
  • 21% genetic (15% chromosomal abnormalities, 32% FGFR2, 25% FGFR3, 19% TWIST1, 7% EFNB1)
  • 67% nonsyndromic
  • 11.5% other syndromes
  • Causative mutations found in 11% multisuture, 37.5% bilateral coronal, 17.5% unilateral coronal
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11
Q

Indications for treatment

A
  • prevent or treat elevated ICP

- address skull deformity to aid in normal social interactions

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12
Q

Early suture closure may…

A

-decrease intracranial volume and restrict brain growth (cephalocranial disproportion) causing elevated ICPs (>15 mmHg)

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13
Q

Causes of elevated ICP in craniosynostosis

A

Cephalocranial disproportion
Intracranial venous congestion
Hydrocephalus
Upper airway obstruction

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14
Q

Intracranial volume in Apert Syndrome

A

Normal range at birth, but increases to greater than 3 standard deviations above normal at 3.5 mo of age, 83% incidence of elevated ICP

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15
Q

Difference in elevated ICP with # of involved sutures

A

Isolated synostosis = 13% incidence of increased ICP

Multiple synostoses = 42% incidence of increased ICP

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16
Q

Signs of elevated ICP

A
  • morning headache, irritability, recurrent emesis, difficulty sleeping
  • mental impairment/neuropsychiatric disorders
  • change in developmental curve
  • optic atrophy and vision loss
  • documented elevated ICP
17
Q

Chiari malformation

A

Downward displacement of cerebellar tonsils through foramen magnum; believed to be secondary to hindbrain growth in a small posterior fossa (in craniosynostosis)
70% of patients with Crouzon’s syndrome, 82% in Pfeiffer syndrome, 100% kleeblattschaedel; may cause noncommunicating hydrocephalus

18
Q

Increased mental impairment associated with

A

Increased number of involved sutures; neurodevelopmental injury is gradual, irreversible, and difficult to detect

19
Q

Physical examination signs of craniosynostosis

A
  • no movement at sutures
  • palpable ridges from thickening of closed sutures
  • bulging fontanelles (Volcano sign)
20
Q

ICP monitoring

A
  • Direct intraparenchymal monitoring (benchmark but invasive)
  • Radiography (AP, lateral, Townes, C spine); Harlequin sign seen on AP view, “thumbprinting” or “copper beating” from pressure gyri on inner table
  • Fundus exam (papilledema)
  • Transorbital ultrasound (measures optic sheath diameter)
  • Visual evoke potentials (measures latency time -prolonged)
21
Q

Sagittal Synostosis

A
  • incidence 40-50%
  • Scaphocephaly/dolichocephaly; “boat shaped”, increased AP diameter and decreased biparietal width, frontal bossing and occipital coning
  • M:F 4:1
22
Q

Metopic Synostosis

A
  • 23-28%
  • Trigonocephaly, “keel shaped, triangular”
  • varied severity; bitemporal narrowing, hypotelorism, bilateral supraorbital retrusion, medial slanted lateral orbital rims, epicanthal folds
  • intracranial findings: Omega sign, hard diagnosis by angle of pterygium to nasion
  • anterior cranial base increased in AP diameter
  • ICP elevation 4-10%
23
Q

Unilateral Coronal Synostosis

A
  • 13-20%

- leads to anterior plagiocephaly

24
Q

Bicoronal synostosis

A

5-10%

leads to brachycephaly/turribrachycephaly

25
Q

Lamdoid synostosis

A

<3%

Leads to posterior plagiocephaly with trapezoid configuration and mastoid bulge

26
Q

Deformational plagiocephaly

A
  • parallelogram configuration with ipsilateral occipital flattening and frontal bossing
  • anterior displacement of ear
  • 1:300 live births
  • results from supine positioning, rotational forces (torticollis)
27
Q

Crouzon Syndrome

A
  • normal extremities
  • AD, FGFR2
  • 1: 25,000 (most common syndromic craniosynostosis)
  • conductive hearing loss, exorbitism, anterior open bite
28
Q

Apert Syndrome

A
  • complex severe syndactyly
  • 1: 100,000- 160,000
  • 70% have decreased IQ
  • 83% have elevated ICP and need VP shunt
  • severe midface hypoplasia, high arch or cleft palate, class III malocclusion (may need trach)
29
Q

Pfeiffer syndrome

A
  • AD, FGFR2 in 95%, FGFR1 in 5%
  • 1: 100,000
  • broad thumbs/halluces, mild cutaneous syndactyly
  • usually no mental impairment
  • midface hypoplasia, strabismus, class III malocclusion and OSA (may need trach)
30
Q

Saethre-Chotzen Syndrome

A
  • AD, TWIST1 mutation
  • 1:25,000-50,000
  • low hairline and eyelid ptosis, facial asymmetry
  • prominent crus helices
  • short stature, partial syndactyly
31
Q

Muenke Syndrome

A
  • Common cause of unicoronal and bicoronal craniosynostosis with high reoperation rate
  • Family history is common
  • 1:10,000
  • AD; pro250Arg mutation on FGFR3 on chromosome 4p
  • thumb-like middle phalanges
  • sensorineural hearing loss
32
Q

Turricephaly

A

excessive skull height and vertical forehead from untreated brachycephaly

33
Q

Oxycephaly

A

pointed head, forehead retroverted and tilted back; from pansynostosis

34
Q

Kleeblattschaedel

A

Cloverleaf deformity; secondary to synostosis of all sutures except squamosal

35
Q

Post-operative monitoring for open cranial vault procedures

A

Hematocrit (txf if <21) and sodium every 6 hrs x 24 hours
Q1h neuro checks
Observation in ICU for 24-48 hours

36
Q

Complications of open cranial vault procedures

A

Bleeding from raw bone (most require transfusion)
Infection (postop fever is common)
Venous air embolism
CSF leak (check intraop with valsalva)

Plastic Surgery - Craniofacial (7 decks)

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