Spine and Tubular Bones

Question 1

Achondroplasia

Inheritance and type?

Answer 1

MC congenital dwarfism
Autosomal Dominant
Rhizomelic micromelia

Question 2

Achondroplasia

Skull findings?

Answer 2

Skull:
Compression at foramen magnum
Brachycephally with pinched base of skull
hydrocephalus
basilar impression
Stretching of optic nerves and pituitary stalk

Question 3

Achondroplasia

Spine findings?

Answer 3

Narrow lumbar interpediculate distance
Concave posterior bodies
Bullet-shaped vertebra in kids
large disc spaces
champagne glass pelvis (squared illii, small sacrosciatic notches, flat acetabular angles)

Question 4

Pseudoachondroplastic dysplasia?

Answer 4

Apparent after 2years
oval/biconcave VB’s with central tongue-like projection (50%)
proximal pointing of MC’s which may resolve
C1-2 instability, odontoid hypoplasia
delayed ossification
mushroom PZoC, small flat epiphyses

Question 5

Homozygous achondroplasia?

Answer 5

lethal
resembles thanatophoric
both parents are achondroplasts

Question 6

Metatrophic Dwarfism

Overview?

Answer 6

Lethal or non-lethal, recessive or dominant
Birth - prominent joints, limited movement
Long, narrow thorax, small tail-like soft tissue fold over sacrum

short extremities + normal elongated trunk at birth, short trunk with kyphoscoliosis later in life

Question 7

Metatrophic Dwarfism

Radiographic findings in extremities?

Answer 7

– tubular bones in extremities are short with marked metaphyseal widening (trumpet/dumbbell shape)
large trochanters (especially lesser (battleaxe appearance)
relatively long fibula
 small flat epiphyses
 delayed ossification of epiphyses/carpals/tarsals

Question 8

Metatrophic Dwarfism

Radiographic findings in spine/skull?

Answer 8

Rectangular/bullet-shaped VB’s in infancy with decreased vertical height, widened IVD’s that become flat, irregular and wedged anteriorly
Presence of a clover leaf skull
abnormal odontoid with atlantoaxial instability +/- neuro deficits
Pelvis – short ilia curved laterally, flat acetabuli, small sciatic and lateral iliac notches, widened Y-shaped triangular fibrocartilage
Short ribs with flared anterior ends, decreased A-P diameter of the thorax, sternal protrusion

Question 9

Diastrophic Dwarfism

Overview?

Answer 9

Twisted”, “crooked”
autosomal recessive
Clinical - short stature, progressive scoliosis and kyphosis, clubfeet, multiple contractures and dislocations, short and broad hands and feet

thumbs and great toes are held in hitchhiker’s position
deformed earlobes because of cystic masses, cleft palate

Question 10

Diastrophic Dwarfism

Radiographic findings?

Answer 10

Marked shortening of tubular bones with wide and rounded metaphyses
delayed appearance of epiphyses

disproportionate shortening of ulna and fibula which is opposite of achondroplasia, +/- dislocation of radial head, bones of hands and feet are small, round/oval 1st metacarpal

equinovarus deformity

M/C foot deformity = valgus hindfoot and metatarsus adduction
Slight narrowing of interpedicular distance in L/S like achondroplasia
+/- Calcification of pinna of ear and airway cartilage

Question 11

Thanatophoric Dwarfism?!

Answer 11

• “Death bearing dysplasia” – M/C stillborn or die shortly after birth due to hypoplastic Lungs
  Cause – dominant new mutation
  numerous skin folds like the Michelin man, narrow AP chest diameter, relatively long trunk

rhizomelic pattern, metaphyseal flaring, osseous bowing and widening, telephone receiver-like femora, flattened VB’s with central constriction giving it an inverted U or H shape on frontals

hemangiomatosis of occipital bone ->clover-leaf skull

Question 12

Chondroecotodermal dysplasia (Ellis-van Creveld syndrome)
Clinical?

Also referred to as Omish Van Creveld because it is commonly due to inbreeding

Answer 12

short-limbed dwarf, ectodermal dysplasia, polydactyly, distal limb shortening, absent/hypoplastic fingernails/toenails, dysplastic teeth, upper lip abnormalities, cardiac defects, congenital Heart disease, renal anomalies, hydrocephalus

Question 13

Chondroecotodermal dysplasia (Ellis-van Creveld syndrome)
Radiographic?

Answer 13

Ribs - like asphyxiating thoracic dysplasia

Shortened tubular bones (especially phalanges)
postaxial (ulnar) polydactyly (especially in hands)
carpal fusion, extra carpals
cone-shaped epiphyses,
enlarged (drumstick) proximal radius and ulna, anterior dislocation of radial heads
wide hypoplastic lateral proximal tibia
medial tibial diaphyseal exostoses, genu valgum
shortened fibula
Normal skull and spine
Prognosis – death due to heart and lung complications in childhood is common.

Question 14

Asphyxiating thoracic dysplasia (Jeune)

Answer 14

constricted chest, mild shortening of extremities, hepatic fibrosis, may die due to pulmonary
X-ray – narrow thorax, short horizontal ribs, wide irregular costochondral junction, high clavicles w/ handlebar appearance, short iliac/pubic/ischial bones, rounded lateral borders, flat acetabular roofs with downward medial/lateral/central spikes (triradiate/trident pelvis)

Question 15

Spondyloepiphyseal dysplasia

Answer 15

mild limb shortening, increased AP chest diameter (Broad bell-shaped chest with decreased vertical height)

decreased height of VB’s
pear-shaped VB’s in infancy, kyphoscoliosis and increased lordosis with anterior wedging/irregularity/generalized flattening of VB’s in childhood
platyspondyly in adulthood
interpediculate distance may be decreased in lower L/S
hypoplasia of odontoid with C1/2 instability
thin IVD’s

Question 16

Cleidocranial dysplasia

Overview?

Answer 16

autosomal dominant, faulty ossification of intramembranous bone
- Recessive form = spondylo-megaepiphyseal-metaphyseal dysplasia

Poorly formed and supernumerary teeth Droopy shoulder with increased glenohumeral ROM
abnormal ear ossicles -> hearing loss

genu valgum, short fingers, +/- respiratory distress due to narrow cone-shaped thorax, normal intelligence, gait disturbances due to deformities of hips

Question 17

Cleidocranial dysplasia

Radiographic findings in child?

Answer 17

poor ossification of skull with wide sutures, multiple wormian bones (M/C in lambdoid suture), +/- absent parietal ossification at birth, persistent metopic suture, widening of coronal and sagittal sutures  hot cross bun appearance, midline defect at symphysis pubis (rami fail to approximate)

Question 18

Cleidocranial dysplasia

Radiographic findings in adult?

Answer 18

brachycephaly, large deformed foramen magnum, platybasia, basilar impression, caudal bulging of occipital bone, underdeveloped paranasal sinuses and mastoids, broad mandible, high arched/cleft palate, absence of a portion of the clavicle (M/C middle/outer, completely absent in 10%), hypoplastic winged scapula, small glenoid, bell-shaped thorax, delayed pubic ossification, wide symphysis pubis, narrow iliac wings, coxa vara (M/C, late) or valga (early), lateral notching of femoral capital epiphysis

Spine – spina bifida occulta (M/C C/S, upper T/S), wedge vertebra with scoliosis, osteopenia, biconvex VB’s, pars defects & increased incidence of spondylolysis, hyperlordosis, excessive kyphosis, scoliosis due to hemivertebra and neural arch defects
Extremities – accessory epiphyses at base of 2nd metacarpal  elongated digit, hypoplastic distal phalanges, large phalangeal epiphyses, pseudoepiphyses of metacarpals, delayed carpal ossification, mild diaphyseal narrowing w/ widened metaphyses,

Question 19

Dyssegmental dysplasia?

Answer 19

short curved limbs, narrow thorax, short neck, limited ROM, hydrocephalus, hydronephrosis, cleft palate, inguinal hernia
X-ray – spine – various size/shape/width of VB’s, coronal/sagittal clefts, wedging, interpediculate space doesn’t widen in L/S (isospondyly = general term used to refer the these abnormal vertebra)

Question 20

Dyschondrosteosis (a.k.a. Léri-Weill syndrome)

Answer 20

Mild mesomelic limb shortening with Madelung’s deformity
Autosomal dominant, expression is M/C in females
X-ray – shortened radius that is bowed dorsally and laterally, distal end of radius tilts towards ulna and volar direction  V-shaped deformity, distal ulna is usually dislocated dorsally, increased distal radio-ulnar space, decreased carpal angle as carpals are wedged into V-shape
Ulna is relatively long compared to radius
Madelung’s deformity - occurs in dyschondrosteosis but can be a separate entity in itself (characteristically bilateral asymmetric seen almost exclusively in females); or may be associated with posttraumatic, dysplastic (dyschondrosteosis, HME), genetic (Turner’s).

Question 21

Metaphyseal chondrodysplasia types? (4)

Answer 21

Jansen type - rare but severe, dominant
Schmid type - autosomal dominant
McKusick type - recessive, also called cartilage-hair hypoplasia
Schwachman-Diamond type: associated with exocrine pancreas insuffiency which leads to malabsorption,

Question 22

Metaphyseal chondrodysplasia - Jansen?

Answer 22

– marked dwarfism, swelling of joints, bowed forearms and legs, frontal hypoplasia, hypertelorism, receding chin

• Subperiosteal bone resorption and fractures have led to diagnostic confusion with hyperparathyroidism, a clinical dilemma that is compounded in some patients by the presence of hypercalcemia.
• X-ray – infant – marked irregularity of metaphyses, widened growth plates, diffuse osteopenia, mild bowing of tubular bones, permeative lucencies throughout long bones, subperiosteal resorption, Fractures
• Childhood – cupped metaphyses with wide zones of irregular calcification that eventually disappear as physis fuses, shortened long bones, metaphyseal flaring, osteopenia of skull, sclerosis of basilar and supraorbital ridges, underdeveloped mastoid air cells and sinuses, mandibular hypoplasia, minimal platyspondyly, flaring of anterior ribs

Question 23

Metaphyseal chondrodysplasia - Schmid?

Answer 23

Clinical – short stature of various severity, bowed legs, manifests after infancy
- X-ray – irregular flared metaphyses (may be V-shaped), widened growth plate (especially knees and hips), coxa vara beginning after 3 yoa, flared anterior ribs, residual shortening and deformity

• The abnormalities in this condition may be confused with the skeletal changes of child abuse.

Question 24

Metaphyseal chondrodysplasia - McKusick?

Answer 24

also called cartilage-hair hypoplasia

• Clinical – normal intelligence, short stature, fine light colored hair, small hands, bowed legs, joint laxity, increased rate of congenital megacolon, complex immune defiency which increases frequency of infections (may cause death) and malignant tumors
• X-ray – minimal epiphyseal flattening, irregular provisional zone of calcification, metaphyseal cupping and flaring (V-shaped, lower extremity affect more than upper extremity), relatively long fibulae  foot deformities, +/- subluxation/dislocation of radial head, bones in hands and feet are small, irregular carpals, small VB’s, odontoid hypoplasia with C1-2 subluxation, mild scoliosis, mild endplate irregularities, flaring and lucent areas in anterior rib ends, short sternum, pectus carinatum

Question 25

Metaphyseal chondrodysplasia: Schwachman-Diamond type

Answer 25

associated with exocrine pancreas insuffiency which leads to malabsorption, etc.

widened lucent provisional zones of calcification with sclerotic areas in metaphyses (LE>UE), abnormal metaphyses are adjacent to normal ones, coxa vara, SFCE, delayed skeletal maturation, osteopenia (due to malabsorption), Scheuermann’s-like disease in spine, short ribs with flared irregular anterior ends, fatty replacement of pancreas can be seen on CT.

Question 26

Multiple epiphyseal dysplasia (Fairbank’s disease)

Answer 26

delayed and disorderly ossification of epiphyses
Clinical – normal intelligence, bilateral symmetric disturbance of 2 or more paired epiphyses, minimal irregularity of vertebral endplates (especially TLJ)

begins around 2-3 yoa  delayed ossification of epiphyses and secondary growth centers, appear fragmented or mulberry-like once ossification begins, secondary centers may be small or flattened
- Older kids – slipped epiphyses, joint incongruity, angular deformities, premature DJD (due to abnormal cartilage and joint incongruity), flaring/irregularity of metaphyses (especially metacarpals and metatarsals), small broad phalanges

• Double patellae – An unusual growth disturbance associated with multiple epiphyseal dysplasia is hypoplastic irregular double patellae. On the lateral and Merchant projections, two crescent-shaped ossification centers are observed one inside the other, classic for multiple epiphyseal dysplasia, results in chronic subluxations and dislocations
• Spine – looks like Scheuermann’s -> endplate irregularities, anterior wedging of VB’s, mild platyspondyly, scoliosis (especially mid T/S)

Question 27

(D) Spondyloepiphyseal dysplasia tarda?

Answer 27

• Manifests between 5-10 yoa, males only
• X-linked recessive condition.
• Mild dwarfism (52-62 inches), back pain, premature DJD which begins shortly after puberty
• X-ray – loss of height M/C due to platyspondyly (especially T/S), hump-shaped or heaping-up VB’s due to hyperostotic bone at posterior 2/3 of VB, early and marked OA, thin IVD’s, ring epiphyses do not ossify, thin disc space, small pelvis, broad thorax with sternal prominence, hypoplasia of dens  instability

Question 28

4 Types of chondrodysplasia punctata?

Answer 28

Rhizomelic type - usually lethal, autosomal recessive
Conradi-Hunermann type - autosomal dominant, normal mentation and life expectancy
X-linked recessive - Short arm of x, lethal in males
Tibia-Metacarpal type - short 4th, short tibia