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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_6009_Библиотеки_им_академика_М_И_Перельмана.pdf
Down Syndrome
KEY FACTS
TERMINOLOGY
• Synonym: Trisomy 21
IMAGING
• Ranges normal CVJ to CVJ bone anomalies ±
atlantooccipital instability (AOI), atlantoaxial instability (AAI)
• ± myelomalacia, syringomyelia, cervicomedullary
compression
• Imaging recommendations
○ Static radiographs to identify CVJ anomalies
○ Dynamic radiographs for CVJ stability assessment
Congenital and Genetic Disorders
○ Bone CT to evaluate CVJ osseous structures
○ Multiplanar MR for cord compression, syringomyelia
TOP DIFFERENTIAL DIAGNOSES
• Achondroplasia
• Mucopolysaccharidoses
(Left) Lateral radiograph of
the cervical spine obtained in
extension shows notable
posterior displacement of the
occipital condyle ſt relative
to the C1 lateral mass superior
articular surface , reflecting
atlantooccipital instability.
(Right) Lateral radiograph of
the cervical spine obtained in
flexion shows anterior
translation of the C1 anterior
ring relative to the
odontoid process st. The
odontoid process is also mildly
hypoplastic. Note flattened
occipital condyles ſt.
PATHOLOGY
• Most common cervical anomalies in Down syndrome
patients
○ Occipital condyle hypoplasia
○ AOI (8–63% of Down syndrome patients)
○ C1 ring hypoplasia (6.7% in small series)
○ Odontoid hypoplasia
○ Os odontoideum
○ AAI (10–30% of Down syndrome patients)
○ Cervical spondylosis
CLINICAL ISSUES
• Hypotonia (infants)
• Asymptomatic (older Down syndrome children)
• Myelopathy, torticollis
DIAGNOSTIC CHECKLIST
• Evaluate for dynamic CVJ instability
130
(Left) Sagittal T1WI MR
reveals mild C1 posterior
ring hypoplasia and anterior
translation of the C1 anterior
ring. The odontoid process st
is mildly dysplastic. Note also
abnormal craniofacial
proportions reflecting
microcephaly. (Right) Sagittal
T2WI MR of the cervical spine
demonstrates a mildly
dysplastic odontoid process st
as well as accelerated
degenerative changes (cervical
spondylosis) at C2/3 ſt.
Mucopolysaccharidoses
KEY FACTS
Congenital and Genetic Disorders
TERMINOLOGY
• Mucopolysaccharidoses (MPS) are inherited lysosomal
storage disorders
• MPS I: Hurler; MPS II: Hunter; MPS III: Sanfillipo; MPS IV:
Morquio
IMAGING
• Craniocervical spine
○ CVJ stenosis, dens hypoplasia, ligamentous laxity,
atlantoaxial instability, thickened dural ring at foramen
magnum
• Thoracolumbar spine
○ Kyphoscoliosis, platyspondyly, anterior vertebral
beaking, ± thoracolumbar gibbus deformity
TOP DIFFERENTIAL DIAGNOSES
• GM1 gangliosidosis
• Mucolipidosis III (pseudo-Hurler polydystrophy)
• Achondroplasia
• Trisomy 21 (Down syndrome)
• Spondyloepiphyseal dysplasia
PATHOLOGY
• Inherited lysosomal enzyme deficiency → storage disorder
○ Autosomal recessive (except MPS II, Hunter; X-linked
recessive)
• Glycosaminoglycan (GAG) accumulates in organs and
ligaments
CLINICAL ISSUES
• Gradual progressive myelopathy
• Clinical neurologic symptoms attributable to brain GAG
deposition, myelination abnormalities, spinal deformities,
peripheral nerve entrapment
DIAGNOSTIC CHECKLIST
• Successful diagnosis requires combination of clinical,
imaging, and genetic/biochemical information
(Left) Sagittal bone CT (MPS
IV) shows flattening and
anterior beaking of all
vertebra, consistent with
Morquio syndrome. The
central beak placement is said
to be more characteristic of
Morquio syndrome than Hurler
syndrome. The odontoid
process is hypoplastic and
nonossified. (Right) Axial bone
CT (MPS IV) following
myelography confirms
moderate central canal
narrowing at the
craniovertebral junction
secondary to osseous
abnormalities as well as
ligamentous thickening.
(Left) Sagittal T1WI MR (MPS
IV: Morquio) demonstrates an
unossified odontoid process
. There is no platybasia or
basilar invagination.
Characteristic hypoplasia of
the subaxial vertebral bodies
ſt is also demonstrated.
(Right) Sagittal bone CT (MPS
IV: Morquio) confirms
nonossification of the
odontoid process ſt as well as
mild hypoplasia of the C3 and
C4 vertebral bodies .
131
Achondroplasia
KEY FACTS
IMAGING
• Shortened vertebral pedicles
○ Decreasing interpediculate distance toward lower levels
of lumbar spine
• Mildly flattened &/or anteriorly wedged vertebral bodies
• Thoracolumbar kyphosis
• Lumbar hyperlordosis
• Small foramen magnum
• T2W: Compression of cervicomedullary junction, spinal
cord, nerve roots → myelopathic hyperintensity in cord
• Other
Congenital and Genetic Disorders
○ Growth disturbance more obvious in proximal limbs
(rhizomelic dwarfism)
○ "Champagne glass" pelvis: Pelvic inlet is flat and broad
○ Squared iliac wings
○ Short ribs
TOP DIFFERENTIAL DIAGNOSES
• Pseudoachondroplasia
(Left) Graphic shows
progressive narrowing of the
interpediculate distance in a
caudad direction. Axial insert
image shows spinal stenosis
related to short pedicles and
decreased interpediculate
distance. (Right) Sagittal T2WI
MR shows a constricted skull
base relative to the visualized
cranial vault. Stenosis of the
foramen magnum
compresses the
cervicomedullary junction,
with mildly increased signal in
the upper cervical cord due to
myelopathic changes.
• Hypochondroplasia
• Diastrophic dysplasia
• Spondyloepiphyseal dysplasia
• Osteogenesis imperfecta
PATHOLOGY
• Usually spontaneous mutation (80%)
○ Results in defective enchondral bone formation
• Autosomal dominant transmission
• Defect in FGFR3, responsible gene mapped to 4p16.3
CLINICAL ISSUES
• Most common nonlethal skeletal dysplasia
• High morbidity from spinal stenosis
○ Surgical correction of progressive/unresolving kyphosis
○ Surgical decompression of foramen magnum in severe
cases; usually symptoms resolve
○ Surgical decompression of stenosis
132
(Left) AP radiograph of the
lumbar spine shows narrowing
of the interpediculate distance
and progressive interpedicular
narrowing between L1 and
L4 ſt, causing narrowing of
the lumbar canal in the
transverse dimension. (Right)
Sagittal T2WI MR shows a
diffusely narrowed AP
dimension of the lumbar spinal
canal, reflecting shortened
vertebral pedicles. Congenital
canal stenosis is further
narrowed by a small disc
protrusion st at L2-L3.
Osteogenesis Imperfecta
KEY FACTS
Congenital and Genetic Disorders
TERMINOLOGY
• Genetic disorder of type I collagen resulting in bone fragility
• Classified into 4 types based on clinical, genetic, and
radiographic criteria
IMAGING
• Severe osteopenia
• Vertebral fractures, kyphoscoliosis
• Multiple long bone, rib fractures
• Enlarged epiphyses, "popcorn" metaphyseal calcifications
• Medullary cavity nearly entirely filled with fat
○ Primary trabeculae sparse but normally oriented
○ Secondary trabeculae nearly absent
TOP DIFFERENTIAL DIAGNOSES
• Nonaccidental trauma
• Congenital dwarfism
• Osteoporosis
PATHOLOGY
• Numerous type I collagen mutations → brittle bone
○ Most autosomal dominant
○ Inherited or spontaneous mutation
• Associated anomalies include blue sclerae, early hearing
loss, brittle teeth, thin fragile skin, joint laxity
CLINICAL ISSUES
• Short stature secondary to multiple spinal and extremity
fractures, kyphoscoliosis, growth plate abnormalities
• Diagnosis suggested by radiographs, confirmed with
ancillary testing
DIAGNOSTIC CHECKLIST
• Important to differentiate from nonaccidental trauma
• Basilar impression and other spinal complications may be
difficult to detect on radiographs
○ Consider MR or CT
(Left) Sagittal bone CT
demonstrates platybasia
and severe basilar impression
with upward displacement of
the remodeled odontoid
process ſt and anterior C1
ring through the foramen
magnum. Metallic posterior
spinal hardware st has been
placed to arrest basilar
impression. (Right) Sagittal
T2WI MR reveals severe
cranial settling and platybasia
with basilar impression of the
odontoid process ſt into the
foramen magnum, producing
ventral cervicomedullary
compression.
(Left) Lateral skull radiograph
in a newborn shows an
abnormal head shape with
numerous wormian bones st
in the lambdoid suture. Also
detected was an abnormal
swan neck deformity of the
cervical spine ſt. (Right)
Anteroposterior radiograph of
the thoracic spine shows
convex right neuromuscular
scoliosis with spinal rods.
There are also osteopenia and
ribbon-like ribs, characteristic
findings of osteogenesis
imperfecta.
133
Spondyloepiphyseal Dysplasia
KEY FACTS
TERMINOLOGY
• Spondyloepiphyseal dysplasia (SED)
• Group of generalized skeletal dysplasias primarily involving
vertebrae, proximal epiphyseal centers
• Affected patients demonstrate short trunk, neck, and limbs
with normal hand and foot size
IMAGING
• Platyspondyly, vertebral hypoplasia & underossification,
abnormal epiphyses
• ± pannus at C1/C2, os odontoideum
Congenital and Genetic Disorders
• Delayed ossification of capital femoral epiphysis → femoral
head flattening, premature osteoarthritis
TOP DIFFERENTIAL DIAGNOSES
• Spondylometaphyseal dysplasia
• Spondyloepimetaphyseal dysplasia
• Multiple epiphyseal dysplasia
(Left) Lateral cervical
radiograph (kyphosis,
myelopathy) obtained in
extension shows platyspondyly
and delayed ossification
status. The odontoid process is
hypoplastic or underossified,
rendering evaluation for
atlantoaxial subluxation
difficult. (Right) Sagittal T1WI
MR (kyphosis, myelopathy) of
the cervical spine reveals
characteristic abnormal
vertebral shape as well as a
large odontoid process
with delayed tip ossification.
No spinal cord compression is
demonstrated.
PATHOLOGY
• SED congenita
○ Abnormal type II collagen synthesis
• SED tarda
○ SEDL gene mutation (vesicular transport protein)
CLINICAL ISSUES
• SED congenita: Diagnosed at birth, short proximal limbs
with normal hand, foot size
• SED tarda: Normal appearance at birth, subsequent
identification of disproportionately short stature in
adolescence or adulthood
DIAGNOSTIC CHECKLIST
• Consider SED congenita for platyspondyly, dysplastic
epiphyses
• Consider SED tarda in adults with short trunk, early
symmetric large joint osteoarthritis
134
(Left) Lateral radiograph of
the thoracolumbar spine
(kyphosis, myelopathy)
demonstrates characteristic
platyspondyly in addition to
focal kyphosis at the
thoracolumbar junction
secondary to a hypoplastic L2
vertebra . (Right) Sagittal
T2WI MR (kyphosis,
myelopathy) of the
thoracolumbar spine confirms
significant stenosis of the
lower thoracic spinal canal
producing focal spinal cord
compression and abnormal
spinal cord T2 hyperintensity
ſt.
Spondyloepiphyseal Dysplasia
IMAGING
General Features
• Location
○ Spine, large joints
• Morphology
○ Extent of osseous abnormalities diffusely distributed
throughout skeleton
– Severity of osseous abnormalities is variable
Imaging Recommendations
• Best imaging tool
○ Plain radiographs for screening
○ Multiplanar CT or MR for further evaluation,
preoperative planning
Radiographic Findings
• Platyspondyly, vertebral hypoplasia, and underossification
• ± os odontoideum
CT Findings
• CECT
○ ± pannus at C1 to odontoid articulation
• Bone CT
○ Platyspondyly, vertebral hypoplasia, and
underossification
○ ± os odontoideum
MR Findings
• T1WI
○ Same as bone CT
○ Improved detection of spinal cord and soft tissue
(pannus) abnormalities
• T2WI
○ Same as T1WI
○ Better detection of spinal cord myelomalacia or
syringohydromyelia
DIFFERENTIAL DIAGNOSIS
Spondylometaphyseal Dysplasia
• Generalized skeletal dysplasia featuring significant
vertebral involvement; affects metaphyseal rather than
epiphyseal portions of long bones
Spondyloepimetaphyseal Dysplasia
• Generalized skeletal dysplasia featuring significant
vertebral involvement; affects both metaphyseal and
epiphyseal regions of long bones
Multiple Epiphyseal Dysplasia
• Primarily affects (multiple) epiphyses
• Relatively mild clinical signs and symptoms
PATHOLOGY
General Features
• Etiology
○ Spondyloepiphyseal dysplasia (SED) congenita
– Abnormal synthesis of type 2 collagen (α-1 chain)
□ Type 2 collagen is primary matrix protein of physeal
and epiphyseal cartilage, major component of
nucleus pulposus, vitreous (eye)
Congenital and Genetic Disorders
□ Other skeletal dysplasias affected by collagen 2
include achondrogenesis type 2,
hypochondrogenesis, Kniest dysplasia, Stickler
dysplasia, autosomal forms of SED tarda, and
spondylometaepiphyseal (Strudwick) dysplasia
○ SED tarda
– SEDL gene mutation encoding vesicular transport
protein
• Genetics
○ SED congenita
– COL2A1 gene mutation, mapped to long arm of
chromosome 12 (12q14.3)
□ Most cases result from random new mutation
– Autosomal dominant (M = F)
– Rare autosomal recessive cases reported
○ SED tarda
– Genetically distinct from SED congenita
– Most commonly X-linked recessive (M > > F)
– Rare autosomal forms described
– Caused by mutation in SEDL (SED late) gene (Xp22)
□ Encodes vesicular transport protein
• Associated abnormalities
○ Cervical instability, spinal curvature (scoliosis, kyphosis,
lordosis), vision (myopia, retinal detachment), hearing
loss, extremity (coxa vara, genu valgum, equinovarus
foot, 2° large joint degenerative disease), nephrotic
syndrome
Staging, Grading, & Classification
• International Nomenclature and Classification of
Osteochondrodysplasias
○ SED congenita, tarda most common
○ Other rare SED variants
– SED Maroteaux type: Musculoskeletal system only
– SED tarda Toledo type: Musculoskeletal + corneal
opacification
– SED tarda (Wynne-Davies): Progressive arthropathy
(similar to juvenile inflammatory arthritis)
– SED with brachydactyly
– SED tarda Namaqualand type
– Pseudo-Morquio disease
– Pseudoachondroplasia SED
CLINICAL ISSUES
Natural History & Prognosis
• No increased mortality
• Osteoarthritis nearly inevitable 2° complication of skeletal
dysplasia
Treatment
• Address musculoskeletal deformities, secondary
complications
DIAGNOSTIC CHECKLIST
Consider
• SED congenita in context of platyspondyly, dysplastic
epiphyses
• SED tarda in adults with short trunk and barrel chest in
conjunction with early symmetric large joint osteoarthritis
135
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SECTION 4
Disorders of Alignment
Introduction to Scoliosis 138
Scoliosis
Kyphosis
Degenerative Scoliosis
Scoliosis Instrumentation
Spondylolisthesis 150
Instability
142
146
148
149
151
Introduction to Scoliosis
Terminology
Scoliosis is considered to be present when there is a coronal
plane curvature of the spine measuring at least 10°. However,
treatment is not generally instituted unless the curvature is >
20-25°. The curvature may be balanced (returning to midline)
or unbalanced. The vertebrae at the ends of the curve are
designated the terminal (or end) vertebrae, whereas the apical
vertebra is at the curve apex.
Disorders of Alignment
Curvatures are described by the side to which they deviate. A
dextroscoliosis is convex to the right, with its apex to the right
of midline. A levoscoliosis is convex to the left, with its apex to
the left of midline.
Curvatures can be categorized as flexible (normalizing with
lateral bending toward the side of the curve) or structural
(failing to correct).
Most scoliotic curvatures are associated with abnormal
curvature in the sagittal plane. These are described as kyphosis
(apex dorsal) or lordosis (apex ventral).
Morphology of the Curvature
Scoliosis due to fracture, congenital anomaly, or infection
typically has an angular configuration. Other causes of
scoliosis tend to have a smooth curvature. Scoliosis most
commonly involves the thoracic spine, followed by the
thoracolumbar spine. In the past, curves were categorized as
primary and secondary (compensatory), but it is often difficult
to make the distinction. Therefore, these designations are no
longer commonly used.
Measurement of Scoliosis
The Cobb method is most commonly used to measure
scoliosis. The vertebrae at each end of the curve (the terminal
vertebrae) are chosen. These are the endplates with the
greatest deviation from the horizontal. The curvature is the
angle between a line drawn along the superior endplate of
superior terminal vertebra and a line along the inferior
endplate of the inferior terminal vertebra. In severe
curvatures, the endplates are often difficult to see. In that
case, the inferior cortex of the pedicle can be used as the
landmark for making the measurement. If measurements are
made on hard copy radiographs, it is usually necessary to draw
lines perpendicular to the endplates and measure the angle
between the perpendicular lines. On most PACS, the
measurements can be made directly from the endplates.
The Ferguson method is another way to measure scoliosis. In
this method, lines are drawn from the center of the apical
vertebra to the center of each terminal vertebrae. The angle
of the scoliosis is the angle between these 2 lines.
Scoliosis is almost always associated with abnormal curvature
in the sagittal plane. The most common finding is loss of
normal thoracic kyphosis. The Cobb method can be used to
determine sagittal plane deformity. Rotational deformity is
often present but can only be grossly assessed on
radiographs. It can be measured on CT scan by superimposing
the apical and terminal vertebra.
Normally, the T1 vertebra is centered over the L5 vertebra in
both the coronal and sagittal planes. Coronal or sagittal plane
imbalance can be measured as the horizontal distance
between the center of the L5 vertebral body and a plumb line
drawn through the center of the T1 vertebral body.
Rotational deformity is present in most types of scoliosis. This
is difficult to measure. Measurement is most easily made by
superimposing axial images of the terminal and apical
vertebrae or by using 3D CT.
Risser Index
Because idiopathic scoliosis tends not to progress after
skeletal maturity, it is useful to assess how close the young
patient is to skeletal maturity. This is commonly assessed by
the Risser method, based on the appearance of the apophysis
of iliac wing. However, this has been shown to be less accurate
than skeletal age assessed on hand radiographs.
• Apophysis not present = stage 0
• Apophysis covers lateral 25% of iliac wing = stage 1:
Bone age 13 yr, 8 mo (F); 14 yr, 7 mo (M)
• Apophysis covers lateral 50% of iliac wing = stage 2:
Bone age 14 yr, 6 mo (F); 15 yr, 7 mo (M)
• Apophysis covers 75% of iliac wing = stage 3: Bone age
15 yr, 2 mo (F); 16 yr, 2 mo (M)
• Apophysis covers entire iliac wing = stage 4: Bone age 16
yr, 2 mo (F); 17 yr, 0 mo (M)
• Apophysis fused = stage 5: Bone age 18 yr, 1 mo (F); 18
yr, 6 mo (M)
Radiology Reporting of Scoliosis
The radiology report should include measurements of all
coronal and sagittal plane curvatures, using the Cobb method.
If bending or supine films are obtained, the radiologist should
report the change in the curvature from the upright film.
Spondylolysis is a frequent finding below the scoliosis, and a
routine search pattern should include evaluation for
spondylolysis.
The radiographs should be evaluated for atypical findings: Are
there any vertebral anomalies? Is the patient osteopenic, and
are fractures visible? Is the thoracic curve to the right (typical)
or to the left (atypical)? Are the curves balanced in the coronal
and sagittal planes, i.e., is the spine centered over L5? Are the
ribs, cardiac silhouette, and paraspinous soft tissues normal?
Role of Advanced Imaging
MR or CT are performed when there is concern for an
underlying abnormality, such as syrinx, tethered spinal cord,
congenital bony abnormality, or tumor.
Suspicion of syrinx is raised when the thoracic curve is convex
to the left or when the thoracic curve does not exhibit lordosis
at its apex. Tethered cord usually presents in childhood but
can be seen in early adulthood, in which it presents with lower
extremity symptoms or bowel and bladder dysfunction.
Treatment of Scoliosis
The goal of scoliosis treatment involves obtaining anchor
points to allow for spine stabilization with potential
correction. This can be accomplished with hooks, wires,
pedicle screws, or cables. Infantile scoliosis (0-3 years)
treatment is performed by casting (Mehta-Cotwel) for growth
modulation (elongation, derotation, and flexion). Juvenile
scoliosis (3-10 years) tends not to progress after skeletal
maturity unless it is severe (> 50-60°). Therefore, minimal
scoliosis is often treated with observation, especially if the
patient is near skeletal maturity. Mild degrees of scoliosis (<
40°) are treated with bracing if continued growth remains.
Bracing has a high rate of success in compliant patients who
wear a brace > 16 hours per day. More severe curvatures are
138
Introduction to Scoliosis
usually treated with fusion, either growing rod constructs for
early onset scoliosis or fusion for those who have completed
growth. Currently, most surgeons use paired posterior rods
and transpedicular screws. Historically, an anterior
transthoracic approach with fusion of the vertebral bodies and
a lateral fusion rod was also common. Harrington rods, which
have hooks at the ends but no pedicle screws, are rarely used
today.
Postoperative Imaging
Imaging is performed after scoliosis surgery to evaluate the
success of the operation. In general, it is irrelevant for the
radiologist to name the brand of instrumentation used and a
simple description is preferable. Postoperative radiographs
must be evaluated first for correction of deformity in the
coronal and sagittal planes. Then the instrumentation is
assessed. On digital radiography, a thin lucent rim is typically
seen surrounding screw threads and is not a sign of loosening.
However, lucencies of > 1 mm suggest screw loosing. Screws
may also back out from the vertebral body (in which case the
screw heads are described as "proud"). Laminar hooks may
become dislodged from the bone or detached from the
fixation rod.
Instrumentation placed for correction of scoliosis provides
rigid fixation as the bone fusion matures. If there is failure of
bony fusion, the instrumentation will fail. CT scans with
reformatted coronal and sagittal images are the most reliable
method for assessing bony union. A CT scan will show gradual
coalescence of bone graft over a several-month period
postoperatively. By the end of 6 months, the graft should
have developed a confluent mass with a well-defined cortex
surrounding the trabecular bone. Facet joint fusion is seen as a
loss of joint space and bridging trabeculae. Intervertebral
body fusion will also show confluent bone.
If there is failure of bony fusion and consequent
instrumentation failure, there may be loss of surgical
correction of the scoliotic curvature. Crankshaft phenomenon
results when the ends of the curvature are fixed but the
intermediate portions are not, so the curve apex may continue
to migrate. This can be seen in early-onset scoliosis (growth
potential).
When reviewing postoperative imaging, a useful pattern is to
evaluate the instrumentation and bone at the fused levels and
then look for abnormalities above and below the fused levels.
In addition to instrumentation failure, common problems
include adjacent segment degeneration, infection, and
insufficiency fractures.
Imaging Protocols
Radiographs are performed to include the entire thoracic and
lumbar spine. If the patient has unequal limb lengths, a lift is
used under the shorter limb. Frontal radiographs are usually
obtained PA instead of AP in order to minimize radiation dose
to the breasts.
A CT scan should always be performed with reformatted
images. Angled reformatted images and 3D reformations are
often useful in assessment of severe curvatures.
Some physicians find it useful to obtain both SPECT and CT
images of degenerative scoliosis. An area of arthritis on a CT
scan, which shows increased uptake on SPECT, is probably a
pain generator.
Disorders of Alignment
MR can be difficult to interpret when scoliosis is severe.
Angled axial images should be obtained based on both
sagittal and coronal scout images and angled along the plane
of the vertebral endplate on both scouts. Sagittal images
should be angled along each segment of the curvature. The
coronal plane is often the most useful for evaluating bony
anomalies, spondylolysis, or degeneration of the discs and
facet joints.
Differential Diagnosis
Idiopathic scoliosis is the most common type and may present
in infancy, childhood, or adolescence. It may have a single
curve or a balanced, S-shaped curve. The thoracic curvature is
usually to the right. The vertebral bodies near the apex of the
curve are often slightly wedged due to asymmetric stress
during growth, but no anomalies are present.
Congenital scoliosis is scoliosis due to an abnormality of
vertebral segmentation. It is associated with hemivertebrae,
block (unsegmented) vertebrae, &/or fusions of the posterior
elements. It often occurs as part of the VACTERL association:
Vertebral anomalies, anal atresia, cardiac anomalies, tracheo-
esophageal fistula, renal and other genitourinary anomalies,
and limb anomalies.
Congenital syndromes may cause scoliosis without vertebral
anomalies. Collagen vascular disorders, neurofibromatosis,
and osteogenesis imperfecta are the most common
syndromes causing scoliosis. The curvatures are variable in
appearance.
Neuromuscular scoliosis is seen in a variety of disorders,
including muscular dystrophy and cerebral palsy. The
curvature is most often a long, thoracolumbar C-shaped curve.
It has a tendency to progress and can be very difficult to treat.
Osteoid osteoma and osteoblastoma may cause scoliosis.
These tumors are very closely related, distinguished primarily
by size and host response. Osteoid osteoma is < 1 cm in size
and surrounded by dense reactive bone. Both tumors secrete
prostaglandins, which stimulate a short-curve scoliosis, with
the tumor on the concave side of the curvature. Prostaglandin
release also often causes bone marrow edema involving
bones not involved with tumor, pleural effusion, or soft tissue
edema. Importantly, scoliosis due to osteoid
osteoma/osteoblastoma is painful, whereas idiopathic
scoliosis is not.
Adult scoliosis is divided into 3 types. The 1st is degenerative
scoliosis, which usually involves the lumbar spine.
Degenerative scoliosis often develops above a surgical fusion,
especially if there is a mild preexisting curvature above the
fused levels. The 2nd type is juvenile scoliosis, which continues
to progress after skeletal maturity. The 3rd type is scoliosis
due to an underlying abnormality, such as limb length
inequality, asymmetric variants at the lumbosacral junction, or
osteoporosis.
Trauma, infection, failure of surgical instrumentation, or
neuropathic arthropathy may cause scoliosis. In each of these
cases, the curvature is short, and the bony abnormality
causing the scoliosis is visible on radiographs.
Chest wall anomalies or thoracic surgery in childhood are an
uncommon cause of scoliosis. In the past, radiation therapy for
Wilms tumor was an important cause of scoliosis, but changes
in radiation therapy technique have rendered that a rare
occurrence.
139