A lateral curvature of the spine with rotational deformity in
the axial spine is true scoliosis. Those with scoliosis can be divided
into those who have an underlying neurologic condition and subdivided
into upper motor neuron (cerebral palsy, Charcot-Marie-Tooth disease)
and lower motor neuron (spinal muscular atrophy, myelomeningocele).
Myopathic conditions include Duchenne’s muscular dystrophy
and arthrogryposis. Connective tissue conditions include Marfan’s
syndrome and osteogenesis imperfecta. One of the most common miscellaneous
categories includes neurofibromatosis. Congenital scoliosis refers
to a failure of segmentation (separation) or formation of the vertebra
which distorts the spine by the absence of normal rectangular vertebrae.
The most common type of scoliosis seen is idiopathic in which an
identifiable cause cannot be found.
This is the most common type of scoliosis, and it can be divided
by age group into infantile (0 to 3 years), juvenile (3 to 10 years),
and adolescent (> 10 years).3 The vast majority
of patients with idiopathic scoliosis present secondary to an observed
abnormal appearance in their spine which is visualized as a shifting
of the body to one side, waistline asymmetry, shoulder height differences,
or a prominence seen in the back. Scoliosis can be defined as a
lateral curvature of the spine > 10°, with rotational deformity
as the hallmark of this spinal curvature.
The incidence of scoliosis in the adolescent period is approximately
2% with only 0.6% of patients requiring treatment.
Adolescent idiopathic scoliosis (AIS) is more commonly seen in girls,
especially when the curves are larger. Although the etiology of
idiopathic scoliosis is not known, we know that AIS curves progress in
two main ways: first, with continued spinal growth curves tend to
progress, and second, if curves are > 45° to 50° at the time of
skeletal maturity, curve progression in adulthood is likely.
Infantile and juvenile scoliosis differ from the more common
adolescent scoliosis in that curve progression is more likely because
patients are younger and underlying neural axis abnormalities (ie,
syringomyelia, tethered cord, diastatometamyelia) are seen in 20% of
patients. An MRI of the entire spine is necessary to identify these
abnormalities. The position and angle of the ribs relative to the spine
at the apex of the deformity are used to predict curve progression.
Patients with idiopathic scoliosis do not present with symptoms
of pain. The deformity is noticed by family members, as well as
nurses when school screening is performed, or by the pediatrician
during annual visits. The physical examination is best performed
with the patient standing in a relaxed position with feet together
and arms at his or her sides. The patient is visualized from the
back to look for shoulder height asymmetry, waistline asymmetry,
or prominences in the back secondary to the rotational deformity.
The Adam’s forward bend test is then performed by having
the patient bend forward at the waist with the arms dangling in
front in a very relaxed position. The rotational deformity of the
spine is easily visualized or palpated (Figs. 216-3, 216-4, and 216-5). Pain with palpation
may indicate a diagnosis other than idiopathic scoliosis, and further imaging
will be necessary. A careful neurologic examination is always performed
in a patient with scoliosis to include a good motor examination,
sensory examination, and most importantly, reflex examination. The
most reliable reflex examination is the presence of abdominal reflexes
in which the abdomen is stroked from medial to lateral. The umbilicus
should move toward the stroked side. Symmetric (right and left)
presence or absence of these reflexes is considered normal, and
asymmetry or absence suggests neurologic abnormality.
Computerized tomography (CT) scan of the spine demonstrating
a congenital abnormality with resultant scoliosis.
Young girl with adolescent idiopathic scoliosis with
a trunk shift to the right and waistline asymmetry.
The Adams forward bend test is used to visualize the
axial plane deformity seen in idiopathic scoliosis.
During the Adams forward bend test, a scoliometer can be utilized
to objectively measure the rotational deformity. In general, patients
with curves > 7° on the scoliometer reading should be referred to
the orthopedist. This usually represents a 20° coronal radiographic
Radiographic imaging can be performed but is often done at the
orthopedist’s office. This includes a standing posteroanterior
(PA) view, as well as a lateral view of the spine to include the
cervical, thoracic, lumbar, and sacrum. On the PA view, the curves
are measured using the Cobb method, which is performed by measuring
the largest curve, and angular measurements are then determined (Fig. 216-6). Other important parameters
on the radiographs include assessment of the Risser sign, the status
of ossification of the iliac wing apophysis which correlates with
the amount of remaining spinal growth. A Risser stage 0 or 1 indicates
significant remaining spinal growth, and a Risser stage 4 or 5 indicates
little remaining growth. Rapid spinal growth is occurring when the growth
plate of the acetabulum (triradiate cartilage) is open and when
girls are premenarchal.
Measurement of the deformity in scoliosis using the Cobb
Treatment for idiopathic scoliosis is 3-fold. First, observation
with serial radiographs every 4 to 6 months is performed in adolescents
for curves < 25° with continued growth remaining. Bracing is
utilized for curves between 25° and 45° in those children who are
growing rapidly. The goal of brace treatment is to prevent further curve
progression to avoid the need for surgery. The effectiveness of
bracing is due to its ability to correct the curve while the patient
is wearing the brace, so that further progression does not occur.
It is important to realize that the braces utilized today go under
the clothes, stay below the arms, and do not need to be seen by
others. Two main types of braces are used depending
on the curve type and curve magnitude. The TLSO (thoracolumbar-sacral
orthosis) or Boston brace can be utilized for all curve types with curve
magnitudes between 25° and 45° and is worn both during the day and
at night. The bending brace or Charleston brace is good for thoracolumbar
or lumbar curves between 25° and 35° and is only worn at night.
The final option is surgical treatment, which is utilized for curves
> 45° to 50° because curve progression into adulthood is likely.
The goal of surgical treatment is to prevent further curve progression
while gaining significant correction of the spinal deformity. The
most common curve type is a right thoracic curve. Preoperatively
the patient needs a thorough evaluation. Indications for MRI include
a neurologic abnormality (most commonly, is asymmetrical abdominal reflexes),
a lower extremity asymmetry or a cavus foot deformity, severe painful
scoliosis, or an atypical curve pattern such as a left thoracic curve.
An MRI analyzes the neural axis for abnormalities such as a syringomyelia,
diastematomyelia, or tethered cord that will then be managed neurosurgically.
Preoperative radiographs include a standing AP and lateral x-ray
of the spine, as well as flexibility x-rays to identify those curves
that are truly structural and not just “compensatory.” A
compensatory curve is opposite in direction to the main structural
curve, attempting to keep the patient in an overall balanced situation.
For example, a right thoracic curve can have a left lumbar compensatory
curve to prevent the patient from having a severe right trunk shift.
Only the curves deemed structural are included in the operative
Surgical treatment can be performed from the posterior approach,
the anterior approach, or with a combined anterior and posterior
approach. The indications for a combined approach (anterior/posterior)
are when a large curve magnitude is present (> 80°) or when the patient
is very young (< 11 years old) with significant remaining spinal
growth. The anterior approach is used to remove disc material to
improve the flexibility of the spine for large curves and achieves
anterior fusion, preventing further anterior spinal growth and return
of the curve in the very young patient. The addition of an anterior
procedure is relatively uncommon today given the advances in posterior
instrumentation techniques. The posterior approach utilizes anchor
points to the spine which then become attached to two rods. These
implants are used to partially correct the spine and then hold the spine
until the vertebrae fuse together in the corrected position (Figs. 216-7 and 216-8).
Fusion of the spine then results in decreased motion of the spine,
which is generally not perceived by the patient; however, the long-term
health of the spine may be somewhat compromised, because the remaining
motion segments function and move to a greater degree. In general,
surgery for AIS achieves between 50% and 70% curve
correction depending on many factors including the flexibility of
the curve, whether compensatory curves are present, and the status
of the spinal cord monitoring at the time of surgery.
Posterior spinal fusion for adolescent idiopathic scoliosis.
The preoperative (left) and the postoperative (right) radiographs.
A single hemivertebra with growth plates on both sides
of the hemivertebra (fully segmented hemivertebra). A scoliosis
occurs secondary to this wedged vertebra.
Overall, surgical treatment for idiopathic scoliosis has a high
success rate. Potential complications include infection, both acute
as well as delayed infections, pseudarthrosis in which one of the
motion segments of the spine fails to fuse, and neurologic deficits
that are extremely uncommon. State-of-the-art intraoperative spinal
cord monitoring is utilized and includes monitoring of
the sensory tracts as well as the motor tracts of the spinal cord.
The overall complication rate for spine surgery in a patient with
AIS is between 4% and 5%, and the incidence of neurologic
deficit is less than 1%.
Scoliosis due to an abnormal formation or separation of the vertebrae
during development is termed congenital scoliosis. The spine develops during
the eighth week of gestation, at which time the renal and cardiac
systems also form, so it is important for these systems to be evaluated when
congenital scoliosis is seen. The most common congenital abnormalities
are failure of formation resulting in a hemivertebrae (a triangular-shaped
vertebrae) or failure of segmentation, in which a bar of bone connects
two or more vertebrae. These spinal deformities can lead to severe
scoliosis and are also associated with congenital rib abnormalities
and fusions that may result in constriction of the chest leading
to pulmonary issues.4
Patients with congenital scoliosis present in many ways, and
treatment may need to be aggressive very early or may only require
observation, depending on the overall curve magnitude and the risk
for progression. A congenital hemivertebrae that has growth plates on
both sides of the vertebrae combined with concave tethering (secondary
to a congenital bar) has a high risk for progression, but a single
hemivertebra without growth on both sides is less likely to progress
(Fig. 216-8). An evaluation of the spinal
cord with MRI is necessary because these patients have a higher likelihood
of having neural axis abnormalities. Treatment for congenital scoliosis
can be very complex, and referral to an orthopedic surgeon at the
time of diagnosis is important. Various options for treatment include
excision of the hemivertebrae with fusion above and below that segment,
use of growing rods requiring surgical lengthening of the rods every 6
months, or placement of a vertical expandable prosthetic titanium
rib (VEPTR) when chest wall and rib deformities are the predominant
Any patient with a neuromuscular condition, such as cerebral
palsy, myelomeningocele, or Duchenne muscular dystrophy, is more
likely to develop scoliosis secondary muscle imbalance or weakness.
These scoliosis curves can occur at any time but are most common
during the adolescent period. They are usually long, sweeping, C-shaped
curves that generally span the entire spine (Fig.
216-9). For those patients who are nonambulators, bracing can
be occasionally utilized; however, the most effective nonoperative
treatment is wheelchair modifications to maintain the patient’s
posture and prevent progression of scoliosis. Surgical treatment
is common because curve progression is rapid and nonoperative methods
to control the curve are challenging and often ineffective. Surgical
treatment usually requires fusion from the proximal thoracic spine
to include the pelvis to ensure adequate correction and maintenance
of that correction over time.5
A typical neuromuscular scoliosis in a patient with cerebral
palsy. Note the left hip is dislocated—a common finding in
patient with cerebral palsy and severe scoliosis.