Achondroplasia of Pelvis



Achondroplasia of Pelvis

1. "Champagne glass" pelvis

[pic]

Normal pelvis shape - brandy snifter

[pic]

2. Achondroplasia of Humerus

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Rhizomelia - "short root"

*Look up other associated signs

[pic]

Central canal stenosis - measurements too small (impingement on thecal sac)

Posterior scalloping (dural ectasia, CSF pulsations)

[pic]

Underdeveloped ischium

Alteration at hip (valgus or varus representation)

Premature DJD

Small foramen magnum (most common lethal complication, usually die during birth)

[pic]

Cleidocranial Dysostosis

Missing clavicle

Only 10% of patients will have complete agenesis of clavicle

Problems with cranial skull development (Wormian bones, cleft palate)

Shape of thoracic cage - to narrow at thoracic inlet, normal base, funnel-shaped)

Measure McGregor's line

Missing body of pubic bone

Lack of clavicle introduces a mobility of shoulder that is not normal (hypermobility of shoulder complex)

[pic]

Funnel Chest

Thoracic cage narrow at top

[pic] [pic] [pic]

Marfan's Syndrome

Long, narrow feet

Arachnodactyly - spider fingers and toes (metacarpals, metatarsals, and phalanges are longer than normal)

[pic]

Ligament laxity

Thumb sign - have patient fold thumb across palm and make a fist

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Marfan's patient has positive thumb sign (can see end of thumb sticking out of palm of hand) - 2 reasons: arachnodactyly and ligament laxity

Need glasses or ocular surgery (lens dislocation)

About 50% will have scoliosis

There is a significant percentage that has pectus excavatum or pectus carinatum (chest maldevelopment)

More lethal - connective tissue maldevelopment of aorta

Average height is over 6 feet

Absence of right heart border and shape of thoracic cage will help us determine chest abnormality

Osteogenesis Imperfecta

Brittle bone disease

Long, thin bones or short, stumpy bones

Short bones - premature closure of growth plate (traps bone in immature dimension)

Rods in lower legs to help prevent fracture (sometimes also in femurs)

Exuberant callous formation

2 major forms:

1. Congenital - worst

2. Tarda form - discovered anytime after birth, fracture easily but not as much as congenital form

Usually short stature

Bone that is under-mineralized

In the eye, there is blue sclera (over 90% of patients will have blue sclera)

Abnormal dentition (small, underdeveloped teeth and cavities easily develop)

[pic]

Melorheostosis

Can add bone to outside but can fill-in intermedullary cavity with bone (inward or outward dense bone)

Neurovascular compression - sensory or vascular abnormalities

Progressive

[pic] [pic] Melorheostosis

Osteopetrosis

*Brittle bone disease

Demonstrate a failure of reabsorption of fetal embryonic bone

May have infections due to decreased marrow so decreased WBC

Usually see tarda form

May change the way we treat these patients

Later we find it the less the severe the presentation

May affect few or many bones

Rugger jersey spine - alternating bands in spine, black, white, black, white, etc. (also called sandwich vertebra)

[pic][pic] Rugger jersey spine

[pic] Osteopetrosis in a 46-year-old man.

Abnormal bone can break and fracture plane can persist for a long time

Bone within a bone appearance

Increased density on plain film will not appear on bone scan

2 Categories:

1. Familial

2. Tarda - most common

Anemia is usually present

Osteopoikilosis

Multiple dense spots

No associated complaints

Age range is 3-73

Asymptomatic

Typically incidental finding

No malignant degeneration or lab findings

MRI presentation is not normal

Does not make bone weaker

[pic]

[pic] [pic]

Osteopoikilosis

Progressive Diaphyseal Dysplasia

Intrusion into medullary cavity

Distortion of cortical medullary junction

Progressive

Only involves diaphysis

[pic] [pic]

Piknodysostosis

*Brittle bone disease

No frontal sinus

Large head

[pic]

No mastoid air cells

Maxillary sinus not well developed

Patient has lost teeth

Obtuse angle of mandible

10% will have mental retardation

Elfin features - craniofacial discrepancies

Shepard's crook deformity - extensive involvement of proximal femur that results in a characteristic varus deformity which resembles a shepard's crook;

[pic]

Acroosteolysis - breaking of bones in hands and feet

Mucopolysaccharide Dysplasia

8 different types

1. Type I Hurler's - Gargoylism

Change in skull, positioning of eye

Hypertelerism

Depressed nasal bridge

Looked normal at birth

Over the next year to year and half the abnormalities develop

1 out 100,000 births

Testing in utero

Difference from achondroplasia is that achondroplasia is identifiable at birth

Inferior or superior beaking of vertebra

[pic][pic]

2. Type IV Murquios

Protruding sternum

Lab keratosulfaturia present in urine

Look normal at birth

Short stature (average 4 feet)

*Middle beaking of vertebra

*Tendency to have underdeveloped odontoid (odontoid hypoplasia)

[pic] Murquios: Middle beaking of vertebra

Spondyloepiphysial Dysplasia

Hump (heaped-up) vertebra

Along endplates

Failure for ring apophysis to mature correctly

[pic]

Anomalies

Occipitalization of the Atlas

"Guess what did NOT happen on the way to the "formation" of the spine?"

Typically, the anterior arch of the atlas is fused to the skull base

–one half of patients with occipitalization of the atlas also have vertebral fusion at the C2-C3 spinal level

–although the odontoid process is high, directly beneath the foramen magnum basilar impression is uncommon

–

♣Significance

–is a normal variant that is asymptomatic in most cases

–hypermobiliy at the ADI

Os Odontoideum

Overall considered uncommon

Ununited ossification centers

Long-standing non-union fracture

Can be absent

♣Significance

–renders the transverse atlantal ligament

incompetent

–potential for significant neurological insult from trivial trauma. High velocity adjusting contraindicated.

Patient may not know

Doctor probably should suspect an abnormality

Not recent

Atlanto-axial instability

Sub-occipital muscle spasm and headaches

VBAI

Wedge-shaped ADI

Boney structures have not fully developed

Ligaments are more lax

Failure of Segmentation AKA Block Vertebra

Embryological failure of sclerotome segmentation and separation first described by Macalister in 1893

[pic][pic]

Fusing of Vertebral Bodies

Causes:

Trauma

Inflammatory arthritides: psoriasis, Rheumatoid arthritis, etc.

Congenital

Infection

Wasp waist appearance

Rudimentary disc - very common

No facet joint

Anterior and posterior fusion - typical

Losing motion

Should perform flexion/extension views to assess ADI

Higher the block the more common the complication

Most common complication is DJD

Higher the block the more strongly it is associated with ADI instability

Sprengels Deformity

Unilateral elevation of scapula

Sometimes presents with omovertebral bone (spine to spine bone bridge) - usually presents 45% of the time

Scapula fail to descend

[pic]

Winking Owl Sign

Appears as if there is no pedicle on plain film

On CT scan, there is evidence of pedicle

Most common cause of this is lytic metastasis

On CT scan, the other pedicle is very dense because doing the work for both pedicles

Best described as hypoplastic pedicle

Can determine if problem congenital or lytic metastasis based on other pedicle (if bright white (more dense) then congenital)

This can occur in other regions (L5/S!) but not called winking owl syndrome because there are not true pedicles in sacral region

[pic]

Variant of Hemivertebra

Growth center did not completely develop

One side of vertebra higher than other side

Produces a structural convexity

[pic][pic]

Butterfly Vertebra

Superior endplate of one vertebra and inferior endplate of next vertebra did not form

Triangular-shaped

[pic]

Spina Bifida Oculta

Spinous process does not develop

No clinical significance

Might palpate as defect

[pic]

Beaked Vertebra

Limbus variant

Anterior part of lumbar vertebra dips down

[pic][pic]

Cupid's Bow

Biconcave endplate

Notochordal persistency

Very common at L5

On CT scan, the inclusion of nucleus pulposus on endplate – Nuclear impression

[pic][pic]

Series of Hemivertebrae

Structural scoliosis

"Scrambled" spine [pic]

Knife-Clasp Deformity

Translocation of growth center

Blade-like spinous process

Can cause back and leg pain

Pain on extension

Hypoplasia of posterior arch

[pic]

Hypoplasia of Posterior Tubercle of C1

Short posterior arch of C1

Spinolaminar line not in alignment (posterior tubercle is further inward)

Have to rule out ADI space and Os Odontoideum

Elongation of Posterior Tubercle and Elongation Between Posterior Cervical Body and Spinolaminar Line of C2 Body

Both are normal variations

Posterior Ponticle

A.k.a. arcuate foramen, Kimmerly anomaly, posticus ponticus

Calcific bridge between the lateral mass and posterior tubercle

In 15% of the population

Proper testing for VBAI is recommended (George's test, etc.)

Approximately 10% of the patients with arcuate foramen demonstrate signs and symptoms

[pic]

♣Significance

–minimal clinical significance or risk

–question of vertebral artery occlusion

Agenesis of posterior tubercle

No spinolaminar line on posterior tubercle

Stress hypertrophy

Failure in segmentation

[pic]Agenesis of posterior arch of C1

Posterior Arch Maldevelopment at L5

Associated with spina bifida oculta

Underdevelopment of Pars Interarticularis

Neck of Scotty dog extremely thin

No contact sports because could cause fracture

Spondylolitic Spondylolisthesis - Anterolisthesis

Look at Myerding's scale and Ullman's line

Slippage of the L5 body anterior on sacral base

Most reliable way to make sure this does not change overtime is to use the percentage method

Surgical stabilization could be an option (more than 3mm of translation)

Etiology is trauma, congenital, stress fracture (obesity, constant loading), pathology (metastasis), or elongated pars (fracture that healed longer)

Stress fracture is the most common etiology

Degenerative is the second most common etiology

Average age of onset of a stress fracture is 18 months old

*3 mm or more of translation in considered unstable*

[pic]

1. Grade I Spondylolisthesis of L5 on S1

2. Bilateral Pars Fracture of L5

Ununited Growth Centers on Tips of T1

Hypoplastic Rib

Under-developed

Intrathoracic Rib

Coming off vertebral body but not wrapping around thoracic cage

Actually goes through lung field

Patient usually does not present with any signs or symptoms

Fused Rib

2 rib heads articulating together - conjoined rib head

Might have problems with chest expansion in that area

[pic]

C7

Transverse processes go down and out

T1

Transverse processes go up and out

Cervical Rib

If it has an accessory articulation then it is known as cervical digit

Linked with thoracic cage

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Cervicothoracic Transitional Segment

No joint space - hypertrophic transverse process on one side

Cervical rib on other side (joint space was visible)

[pic]

Rib Cartilage

Costochondral calcification

No increased serum calcium levels

Physiological calcification

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Hip DJD (young patient)

Decreased joint space

Congenital hypoplasia of the acetabulum

Underdevelopment of the acetabulum can cause wear and tear and early DJD

[pic] [pic]

23-year-old female with congenital hip hypoplasia.

Pseudotumor of the Pelvis

Growth center and as bone matures it disappears

Bilateral and symmetrical

On inferior ramus

Coxa Valga

Measure femoral neck angles

More than 130 degrees

Children usually in valgus range

[pic] [pic]

Congenital Hypoplasia of Ischium and Pubis

Underdevelopment

Pectus Excavatum (Funnel Chest)

Heart displaced to left

Thoracic ribs steeper than normal

Reduced AP diameter

[pic]

Sacral Agenesis

No sacrum

L5 articulates directly with the ilium

Bipartate Sesamoid

2 sesamoid bones on big toe

May be bilateral but will not be symmetrical

[pic][pic]

Supracondylar Process

Bone projection

Might be confused with osteochondroma (benign tumor)

Always on humerus and always points to elbow

Single projection

[pic]

Osteochodroma

Consists of bone and cartilage (mixed density) - benign

On many bones

When they are on long bones, they point away from joint

Does not have ligamentous attachment

[pic] [pic]

Madelung Deformity

Occurs in wrist

Carpals are not aligned

[pic]

Polydactyly

More than normal amount of digits

Can occur with fingers or toes

[pic]

Apert's

Mitten hand - glove hand

[pic][pic]

Malformation of the skull

Brachicephaly - skull taller than normal and thinner than normal in A-P view - coronal sutures closed too early

[pic]

Scaphocephaly - long, narrow - "boat head" - midsagittal suture does not grow normally

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Lumbosacral Transitional Segments

Sacralization

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Lumbarization

Type Ia - single TP that is taller than 19mm

Type Ib - pair of TP's that are both taller than 19mm

Clinically Significant Transitional Segments:

1. Type IIa - single accessory articulation, disc at transitional level has high rate of disc herniation, also disc at above level

[pic]

2. Type IIb - pair of joint articulations, also has high rate of disc herniation (not as high as Type IIa), also disc at above level

Type IIIa - bone bar - partial sacralization, no intersegmental motion, cannot exert any force on the disc

[pic]

Type IIIb - full sacralization, pair of bone bars, no motion

Type IV - accessory joint on one side and bone bar on the other side - bone bar will trump the joint - bone bar produces fixation

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