SBA Adolescent Idiopathic Scoliosis

1. A 13-year-old female presents to clinic after being told that she has scoliosis. She has no
pain and has had no treatment up to this point. Figure A shows her radiograph with a 32°
curve. An MRI showed no spinal cord abnormalities. What is the most appropriate
treatment and expected outcome given her age and degree of scoliosis?
1 Observation with a 100% chance of
progression to >50° deformity
2 Rigid TLSO for 2 hours/day with a 75%
decrease in the need for surgery
3 Rigid TLSO for 13 hours/day with a 50%
decrease in the need for surgery 32° curve in a
skeletally immature
4 Rigid TLSO for 24 hours/day with a 100% (Risser 2) patient.
decrease in the need for surgery
5 Posterior spinal fusion
Answer 3
• Adolescent idiopathic scoliosis (AIS) can be effectively treated with bracing. Indications
for bracing include skeletally immature patients with flexible curves measuring >25° and
<45°. Various brace designs exist but there is no substantial evidence that one type of
brace is more effective than another. However, compliant brace wear of at least 12.9 hours
in these patients has been shown to decrease the risk of progression and allow patients to
reach skeletal maturity with a curve <50°. Compliance can be improved with frequent
office visits and patient/family education.

Weinstein et al. conducted a multi-center trial studying both a randomized arm and a
reference arm in regards to bracing versus observation. They found that 72% of curves
treated with bracing were kept from progressing compared to 48% of curves treated with
observation alone. The trial was stopped early due to the efficacy of bracing. They
concluded that bracing is an effective treatment for AIS in skeletally immature patients if
compliance of at least 12.9 hours of daily brace wear is achieved.

Gomez et al. reviewed the nonsurgical management of AIS including the various bracing
options and the Schroth method of daily exercise and postural control to limit curve
progression. They state that effective nonoperative treatment of AIS relies on a working
relationship between all team members and the family, a knowledge of the biomechanics
of the curve, and compliance with treatment principles.
• Incorrect Answers:
• Answer 1: Observation would not be indicated due to a higher likelihood
of curve progression and the need for surgical stabilization.
• Answer 2: Compliance of at least 12.9 hours/day is needed to achieve the
maximal benefit of bracing and to decrease the need for surgery.
• Answer 4: Even with 24-hour bracing, this curve could progress to >50°
and require a posterior spinal fusion.
• Answer 5: Posterior spinal fusion would be too aggressive in this patient,
given that she may never reach a 50° curve with appropriate bracing.
2, A 16-year-old female with adolescent idiopathic scoliosis undergoes posterior spinal
fusion with instrumentation. The thoracic pedicle screws were placed using a tap 1 mm
smaller than the screw diameter and a straightforward trajectory that runs parallel to the
superior endplate. This techniques allows for which of the following
1 Anatomic placement of the screws.
2 Increased depth insertion of the screws.
3 Increased maximal insertional torque.
4 Decreased resistance to screw pullout.
5 Decreased stability of the construct.
Answer 3
• Contemporary segmental pedicle screw placement used in the treatment of scoliosis
deformity offer significantly higher screw pullout and deformity correction than prior
hook and wire constructs. Additionally, screw insertional torque has been found in
numerous studies to correlate with resistance to screw pullout. Several factors have been
found to increase maximum screw insertional torque, including tapping 1mm smaller than
the screw diameter and using the straightforward trajectory. It is important to note that
while under-tapping makes for a stronger screw, there are some studies that suggest not
tapping at all makes for an even stronger screw.

Lehman et al. performed a biomechanical study evaluating maximum insertional torque

when tapping line to line, under-tapping by 0.5mm, and under-tapping by 1mm in 34
fresh frozen cadavers. They found under-tapping the thoracic pedicle by 1mm increased
maximum insertional torque by 47% when compared to under-tapping by 0.5mm and by
93% when compared to line to line tapping.

Kuklo et al. performed a biomechanical study on thirty cadavers using the straightforward
technique (sagittal trajectory of the screws parallels the superior endplate of the vertebral
body) versus anatomic trajectory (22 degrees in the cephalo-caudad direction in the
sagittal plane). They found maximum insertional torque to be 2.58 pounds using the
straightforward technique versus 1.86 pounds using the anatomic trajectory (p=0.0005).
• Incorrect Answers:
Answer 1: These techniques do not allow for anatomic placement of the
screws. An anatomic trajectory would also decrease the maximum insertional
torque.
• Answer 2: Depth insertion is not based upon tapping or using the
straightforward technique.
• Answer 4: Resistance to screw pullout is directly correlated with maximum
insertional torque, and would be increased by undertapping 1mm and by using
the straightforward technique.
• Answer 5: Stability of the construct is increased by using the techniques
described in the question as the maximum insertional torque and resistance to
screw pullout would increase.
3. A 12-year-old girl who is 3 months postmenarchal undergoes full-time brace treatment
for scoliosis. The posteroanterior radiograph taken at that time reveals a right thoracic curve
measures 28 degrees, and the left lumbar curve measures 23 degrees. At age 15, after 3
years of bracing, a repeat posteroanterior radiograph is obtained, now revealing a right
thoracic curve measuring 11 degrees and the left lumbar curve measuring 19 degree, and
Risser 4. Which statement is best indicated in course of action in this patient?
1. Discontinuation of bracing as she has
reached skeletal maturity.
2. Continue full-time bracing until skeletal
maturity.
3. Continue nocturnal bracing until skeletal
maturity.
4. Posterior spinal fusion.
5. MRI of the cervical, thoracic and lumbar
spine.
Answer 1
• Curves <25° can be treated with observation, while flexible curves from 25° to 45° in skeletally
immature patients (Risser 0, 1, 2) should be treated with bracing. Bracing success is most
commonly defined as <5° curve progression and failure is 6° or more curve progression at
orthotic discontinuation (skeletal maturity), absolute progression to >45° either before or at
skeletal maturity, or discontinuation in favor of surgery.
• Skeletal maturity is defined Risser sign 4, <1cm change in height over 2 visits 6 months apart, 2
years postmenarchal.

Richards et al. attempted to define parameters for future AIS bracing studies. Outcome measures
should include patients with (1) <5° curve progression vs >6° progression at maturity, (2) curves
exceeding 45° at maturity, or those who have had surgery recommendation/undergone.

Negrini et al. performed a Cochrane systematic review. Basing conclusions on 2 studies, they
found that (1) a brace treated curve progression (74% success) better than observation (34%
success) and electrical stimulation (33% success), and (2) a rigid brace is more successful than an
elastic one (SpineCor) at curbing curve progression.
• Incorrect Answers:
• Answers 2 and 3: Brace cessation is appropriate as she has
reached skeletal maturity, and bracing was successful. Only
observation is necessary at this stage.
• Answer 4: Surgery is only indicated if bracing was
unsuccessful.
• Answer 5: MRI is indicated if red flags are present. These
include atypical curve (left thoracic, short angular curve, apical
kyphosis), rapid progression, hyperkyphosis, structural
abnormalities, neurologic symptoms or pain, foot deformities
and asymmetric abdominal reflexes.
4. The 'Risser sign' is one of the most commonly used markers for skeletal maturation and
growth potential in patients with adolescent idiopathic scoliosis. What 'Risser sign' has been
shown to correlate with the greatest velocity of skeletal linear growth?

1 Risser 0
2 Risser I
3 Risser II
4 Risser III
5 Risser IV
Answer 1
• There are two stages of life where the velocity of postnatal skeletal growth is most
rapid.
• These are: (1) during the first year of life and (2) puberty. Both correlate with a Risser
sign of 0. Risser 0 covers the first 2/3rd of the pubertal growth spurt and correlates
with the greatest velocity of skeletal linear growth.
Risser grades range from 0 to V and are a measure of the progression of ossification in
the pelvis. The Risser sign is usually referenced in clinical decision-making regarding
adolescent idiopathic scoliosis.
Biondi et al. examined 111 patients to determine the relationship between the accuracy
of the Risser sign and bone age determinations. They found that the iliac crest
apophysis maturation correlated with skeletal age assessment. They suggest that Risser
sign is a reliable method for assessing skeletal bone age.
Risser I: is given when the ilium calcification measures 25%. As this stage the velocity
of linear skeletal growth is on a descending slope.
Risser II: the greater trochanteric apophysis unites with the femur and Ilium
calcification measures 50%. There is usually 3 cm of sitting growth remaining and no
further growth in the lower extremities.
Risser III: Ilium calcification measures 75%. There is usually 2 cm of sitting
growth remaining.
Risser IV: Ilium calcification is almost complete. There is usually 1 cm of sitting
chart showing the rate of growth Risser staging system from 0 - V.
correlated with the Risser staging system
5. Skeletal maturity is an important variable in the progression of idiopathic scoliosis.
Which stages of skeletal maturity would be expected to have the highest risk of progression
of an idiopathic scoliotic curve?

1. Risser 3
2. Risser 5
3. Risser 0 patients with closed triradiate
cartilages
4. Risser 0, when the triradiate cartilage has
started to fuse but the iliac crest apophysis
has
5. Risser 4
Answer 3
• DiMeglio et al. published a review of factors to consider when evaluating the potential
progression of a scoliotic curve. They report that Risser 0 is present during the initial two-
thirds of pubertal growth and that ossification patterns of the elbow can also be used
during this critical time period (Illustration A).

Ryan et al. published a retrospective review of patients with adolescent idiopathic

scoliosis (AIS) that underwent brace treatment. They identified a significantly lower
likelihood of progression in patients with closed triradiate cartilages at the time of
bracing.

Nault et al. found limited reliability of the Risser grading system in determining the onset
of the curve acceleration phase based on the digital skeletal age (DSA). They proposed a
modified system based on the fact that Risser 0 patients with open triradiate cartilages
were all seen prior to the curve acceleration phase, and that Risser 0 patients with closed
triradiate cartilages and Risser 1 patients were within peak growth velocity.
6. A 12-year-old female is referred to the office by a community orthopaedic surgeon
concerned that her shoulders appear to be at different heights. With Adam's forward
bending, she is noted to have a significant right thoracic rib prominence. She denies pain. A
detailed neurological examination reveals no abnormalities. Radiographs of her spine show
an apex left lumbar curve measuring 32 degrees and an apex right thoracic curve measuring
28 degrees. She had her first menses last month and her Tanner-Whitehouse staging is
consistent with an adolescent steady state. The most appropriate treatment would be?
1 Posterior spinal fusion
2 Spinal manipulations
3 Observation and referral to an
endocrinologist
4 Thoracolumbosacral orthosis
5 Halo-gravity traction
Answer 4
• Assessing a child's skeletal maturity has important clinical implications when treating
patients with idiopathic scoliosis. The Tanner-Whitehouse III method specifically uses the
distal radial and ulnar epiphyses, as well as the metacarpal and phalangeal epiphyses of
the first, third, and fifth digits for determination of skeletal age. A Tanner-Whitehouse
Stage in 'adolescent steady-state' means she is past peak height velocity. However, as she
is before skeletal maturity, and her lumbar and thoracic curvatures are > 25 deg., these
curvatures may continue to progress. Therefore, bracing would be the best treatment
option at this time.

Hasler et al. randomized twenty post-pubertal young women (20°–40° idiopathic

scoliosis to an observation or complementary and alternative osteopathic treatment in a
prospective study. Pre- and post- intervention trunk morphology and spine flexibility were
assessed at 3 month intervals. A regression analysis of repeat measurements revealed no
therapeutic effect on rib hump, lumbar prominence, plumb line, sagittal profile or global
spinal flexibility with either treatment.

Sponsellar et al. examined the literature form the past 25 years to summarize the current
practice of bracing in the treatment of adolescent idiopathic scoliosis. They found the
highest level of existing evidence from a prospective center-randomized study, which
showed that thoracolumbosacral bracing was most effective for single curves of 25 to 35
degrees in female patients with a starting Risser score of 0 to 2.
• Incorrect Answers:
Answer 1: Posterior spinal fusion can be used for all types of idiopathic scoliosis.
However, the indications for posterior fusion in this patient would include, failed non-
operative treatment, rapidly progressing curvatures, symptomatic double curvatures, cobb
angle > 45 degrees.

Answer 2: Spinal manipulation is considered an alternative and complementary treatment

for idiopathic scoliosis. There is little evidence that supports or refutes this treatment. It is
currently not supported.

Answer 3: Observation alone may be warranted in skeletally mature patients with stable
curvatures <25 degrees. As this patient has a double curvature, bracing should be the initial
treatment with close follow-up to assess for progression.

Answer 5: Halo-gravity traction has been used pre-operatively before spinal operative
spinal stabilization for scoliosis. This would not be suggested in this patient as first line
treatment.
Tanner-
Whitehouse III
skeletal
maturity
assessment.
7. The orthosis thoracic lumbosacral orthosis Milwaukee is indicated for the treatment of
the spinal deformity.

1. Cobb angle 4 • In contrast, similar curves <25deg are best treated with
2. Cobb angle 90 observation, and those >40deg do not respond favorably to
bracing.
3. Cobb angle 50
4. Cobb angle 35
5. Cobb angle 40
Answer 4
• Fayssoux et al. discuss the history of bracing. Brace treatment is indicated for children
and adolescents with curves of 25-40deg who have at least 2 years of growth remaining
(Risser 0,1,2 and <1yr postmenarchal). Bracing is contraindicated in severe hypokyphosis
and severe rib deformities. Rigid TLSO (worn 18-23h/day) is standard of care for
idiopathic thoracic curve with apex at or below T7.
Schiller et al. recommend bracing curves >30deg on initial presentation, or curves that
progress >10deg to a magnitude >25deg. Bracing should continue until growth stops
(unchanged height 6mths apart, Risser 4 in females or Risser 5 in males, postmenarchal
18-24mths, or skeletal maturity on bone age determination).
Hedequist et al. discuss congenital scoliosis. They state that primary bracing is rarely
indicated because braces usually do not affect progression as congenital curves are
inflexible and unresponsive to bracing. Continued efforts at bracing may cause chest wall
deformities in young children with compliant thoracic cavities.
Weinstein et al. examined the effectiveness of bracing in idiopathic scoliosis. The rate of
treatment success was 72% after bracing compared with 48% after observation. Intention-
to-treat analysis revealed success rates of 75% and 42% respectively.
8. Which of the following methods of determining skeletal maturity correlates most closely
with the curve acceleration phase for children with idiopathic scoliosis?

1 Lenke classification • Incorrect Answers:

method Answer 1: The Lenke classification refers to scoliotic
2 Greulich and Pyle curves, not skeletal age determination.
method Answer 2, 3, 5: The Tanner-Whitehouse RUS method
3 Oxford method more closely correlates with the curve acceleration phase
than either the Oxford method, Risser sign, or the
4 Tanner-Whitehouse III
Greulich and Pyle method.
5 Risser sign
Answer 4
• Assessing a child's skeletal maturity has important clinical implications when treating
patients with idiopathic scoliosis. Current methods include the Greulich and Pyle method,
the Oxford method, the Risser sign, and the Tanner-Whitehouse III method. The Tanner-
Whitehouse III method specifically uses the distal radial and ulnar epiphyses and the
metacarpal and phalangeal epiphyses of the first, third, and fifth digits for determination
of skeletal age. In contrast, the Risser sign refers to the amount of calcification of the
human pelvis as a measure of maturity. While the Tanner-Whitehouse method is more
time consuming, it provides a better assessment of maturity and prognosis determination
for curve progression in idiopathic scoliosis.

Sanders et al. (2007) evaluated a variety of maturity measurements and how closely they
are related to scoliosis progression. They found the Tanner-Whitehouse-III RUS method
was superior to all other indicators of maturity.

Sanders et al (2008) discussed a simplified version of the Tanner-Whitehouse III

classification for skeletal maturity assessment. Their classification consists of 8 stages,
from the juvenile slow stage to the mature stage, and is based on the radiographic
appearance of all digital epiphyses. They found high intra- and extra-observer reliability,
and a close correlation to the behavior of idiopathic scoliosis.
9. A 13-year-old girl is referred to the orthopedic clinic for evaluation of scoliosis. She
denies back pain and states she began her menses 3 months ago. On Adams forward
bending, she measures 6 degrees. She has 5 of 5 motor strength in all muscles groups in her
lower extremities and symmetric patellar and Achilles reflexes. A standing PA and lateral
radiograph is shown in Figures A and B. All of the following should be performed as part of
her evaluation EXCEPT

1 Evaluation of leg lengths

2 Assessment of abdominal reflexes
3 Evaluation of waist asymmetry
4 Evaluation for café-au-lait spots
5 MRI
Answer 5
• a 13-year-old-girl with a right-sided thoracic curve of 18 degrees with an associated
thoracolumbar curve. An adequate physical exam includes an evaluation of spinal
balance, leg lengths, shoulder height, waist asymmetry, café-au-lait spots, foot deformities
and reflexes.

An MRI is not part of the initial evaluation in patients with idiopathic scoliosis without
red flags or abnormal curve types. Typical indications for MRI include patients with a left
thoracic curve, abnormal reflexes, rapid curve progression, neurologic symptoms,
excessive kyphosis and foot abnormalities.

Based on her skeletal maturity, curve magnitude, and menarche status, the risk of curve
progression is low. In females, the onset of menses typically occurs one year after peak
height velocity. In this scenario, treatment can consist of observation with further follow-
up.
10. In patients with adolescent idiopathic scoliosis, bracing is indicated in which of the
following conditions

1 Any patient with a curve of greater than 25 degrees

2 A 11- year-old boy with a Cobb angle curve of 50 degrees
3 A premenarchal girl with a Cobb angle curve of 30 degrees
4 A growing child with 6 degrees of progression with a 12 degree curve
5 A girl who is Risser 4, Sanders 7, with a 30 degree curve.
Answer 3
• Brace treatment may be beneficial for a patient with substantial growth potential (Risser 0-2,
Sanders 1-3) and a moderate curve (20-45 degrees). Bracing is effective at limiting curve
progression in this population, but it does not diminish a curve. Furthermore, bracing curves > 45
degrees has not been shown to limit curve progression and this population maintains a higher risk
of ongoing progression into adulthood.

Weinstein et al. evaluated both a randomized and preference-based cohort of bracing versus
observation. The trial was stopped early due to efficacy of bracing. The rate of treatment success
was 72% after bracing and 48% after observation. Treatment success was strongly correlated to
time of brace wear.

Sponseller et al. examined the literature form the past 25 years to summarize the current practice of
bracing in the treatment of adolescent idiopathic scoliosis. They found the highest level of existing
evidence from a prospective center-randomized study, which showed that thoracolumbosacral
bracing was most effective for single curves of 25 to 35 degrees in female patients with a starting
Risser score of 0 to 2.
• Incorrect Answers:
Answer 1: Patients with a 25 degree curve are only indicated for bracing if they are
Risser 0-2
Answer 2: A boy with a curve of 50 degrees should be treated with surgery regardless
of skeletal maturity
Answer 4: A skeletally immature boy with 6 degrees of progression leading to a
current curve of 12 degrees should be treated with observation alone
Answer 5: Bracing would not be effective in a girl who is Risser 4, Sanders 7, with a
30 degree curve, because she is nearly skeletally mature and her risk of progression
to greater-than 40 degrees is very low.
11. A 12-year-old girl who is Risser stage 3 has had intermittent mild midback pain for the
past 4 weeks. The pain is worse after prolonged sitting and after carrying a heavy backpack
at school. She occasionally takes acetaminophen, but the pain does not limit sport activities.
Examination reveals a mild right rib prominence during forward bending. Neurologic
examination is normal. Radiographs show a 20-degree right thoracic scoliosis with no
congenital anomalies or lytic lesions. Management should consist of

1 back muscle stretching and reduced weight in the backpack.

2 consultation with a pain management specialist.
3 MRI of the thoracic spine.
4 a technetium Tc 99m bone scan.
5 a thoraco-lumbosacral orthosis.
Answer 3
• Mild scoliosis is not a painful condition, but it usually presents during adolescence.
Intermittent back pain is reported by 25% to 30% of adolescents whether or not scoliosis
is present.
• Such pain is often attributed to muscle strain from tight muscles, poor posture, or heavy
school backpacks.
• The clinician must distinguish typical pain (mild, intermittent, nonlimiting) from atypical
pain. The latter requires more careful examination and imaging studies (bone scan or
MRI) to determine the source of pain. The patient’s age and right thoracic curve pattern
are typical for idiopathic scoliosis; therefore, imaging of the neuroaxis is not necessary to
look for cord syrinx, tethering, or tumor.
• Brace treatment is not required for this small curve unless future progression is
demonstrated.
12. What risk factor is most associated with progression of idiopathic scoliosis to a curve
requiring surgery?

1 Curve magnitude of more than 20 degrees at menarche

2 Curve magnitude of more than 30 degrees at the peak height
velocity
3 Curve magnitude of more than 30 degrees at skeletal age 12 years
4 Curve magnitude of more than 30 degrees at Risser grade 2
5 Curve flexibility of less than 50% at Risser grade 2
Answer 2
• The magnitude of the curve at the time of the peak height velocity is the
most prognostic sign in relationship to surgery. More than 70% of curves
that measure more than 30 degrees at this time are likely to reach surgical
range.
13. A 12-year-old female presents with a left thoracic rib prominence. Physical exam shows
absent abdominal reflexes in the upper and lower quadrants on the left side, but present on
the right. A PA standing radiograph is shown in Figure A. What is the next step in
management?
1 Observation with repeat radiographs in 6 months
2 Bracing with a thoraco-lumbar-sacral orthosis
3 Magnetic resonance imaging (MRI)
4 Posterior spinal fusion with instrumentation
5 Anterior and posterior spinal fusion with
instrumentation
Answer 3
• The clinical presentation is consistent with a left thoracic curve with abnormal abdominal
reflexes and therefore an MRI is indicated to look for abnormalities of the neural axis
such as Chiari malformations and syringomyelia. One should recognize that right thoracic
curves are more commonly seen in idiopathic scoliosis.

Spiegel et al performed a a retrospective radiographic review on 41 patients with scoliosis

associated with a Chiari I malformation and/or syringomyelia. Approximately 50% of
patients had an "atypical" pattern (left thoracic, double thoracic, triple, long right
thoracic). They recommend that MRI should be considered in these patients.

Yngve et al reviewed the sensitivity of abnormal abdominal reflexes on physical exam.

They found the finding of abdominal reflexes consistently present on one side and
consistently absent on the other side did not occur in normal subjects. They recommend
further workup with an MRI if found in a patient with scoliosis.
• MRI shows a large syringomyelia with
dilatation in the lower cervical and upper
thoracic area. Also noted was an Arnold-
Chiari malformation. This patient was
referred to a neurosurgeon and treated
with a posterior fossa decompression.
14. An isolated long-segment instrumented posterior spinal fusion is considered in which of
the following clinical situations?
1 A 13-year-old female, Risser 3, with adolescent idiopathic scoliosis (AIS) and a
Cobb angle of 55 degrees
2 A 5-year-old male, with juvenile idiopathic scoliosis (JIS) and a Cobb angle of
55 degrees
3 A 2-year-old female with infantile idiopathic scoliosis (IIS), a flexible curve
with a Cobb angle of 35°, and a RVAD of 25°
4 A 7-year-old with a progressive spinal deformity. Imaging demonstrates a T9
failure of formation with contralateral segmentation failure
5 A 13-year-old female Risser 2, with AIS and a Cobb angle of 27 degrees
Answer 1
The type of scoliosis, magnitude of curve, and patient's expected future growth are
essential considerations when planning surgical management; patients with a great deal
of remaining growth (e.g., IIS, JIS) may require non-fusion procedures to prevent
crankshaft as well as alterations in chest wall growth and pulmonary development
• de Kleuver et. al. documented international consensus opinion for the treatment of AIS.
There was 100% consensus that patients with AIS should not undergo routine anterior
releases. In patients with large, rigid curves, the use of Ponte osteotomies could be
considered for mobilizing rigid segments and achieving adequate correction.

Hedequist et. al. reviewed the management of congenital scoliosis. Patients with
formation failures (hemivertebrae) and contralateral segmentation failures (vertebral bars)
have the highest risk of curve progression and are best managed surgically. These patients
frequently require segmental vertebrectomy or wedge resection in addition to selective
fusion to prevent progressive deformity.

Lenke et. al. reviewed the optimal management of JIS, which is an idiopathic scoliosis of
children aged 3 years to 9 years 11 months. The decision to fuse these patients is difficult
as there is a high risk of growth arrest to the spine, chest wall, and lungs. Additionally,
posterior-only fusion procedures are frequently complicated by continued curve
progression through anterior spinal growth, a condition known as the "crankshaft"
phenomenon. Surgical options for these patients include use of growing rods, gravity-halo
traction, growth modulation techniques (such as convex disc stapling), and combined
anterior/posterior spinal fusion.
• Incorrect Answers:
• Answer 2: In JIS, fusion, if indicated, should include anterior and posterior
columns to prevent crankshaft phenomenon.
• Answer 3: In infantile scoliosis, the risk of progression is elevated in patients
with RVAD >20 degrees. Children with a curve magnitude >30 deg and
RVAD >20 are indicated for Mehta de-rotational casting. Only curves with
Cobb angle >50-60 degrees are indicated for surgical intervention.
• Answer 4: This patient presents with a unilateral hemivertebra with a
contralateral bar. There is a high risk of progression and would benefit from a
bar excision in addition to posterior fusion.
• Answer 5: Skeletally immature patients with AIS and a curve magnitude from
25-45 degrees are indicated for bracing, not surgical correction.
15. In the treatment of thoracolumbar idiopathic scoliosis using an anterior single rod
technique with interbody cages, which of the following variables has been associated with
pseudoarthrosis.

1 Thoracic curve coronal correction of > 40%

2 Thoracolumbar/lumbar curve coronal correction > 50%
3 Smaller adolescents (<50 kg)
4 Failure to maintain lumbar lordosis of > 45 degrees
5 Thoracic hyperkyphosis (>40 degrees )
Answer 5

• In select patients with thoracolumbar idiopathic scoliosis, an anterior approach with a

single rod and interbody cages may be indicated.
• In a prospective study, Sweet et al found anterior instrumented fusions using a single solid
rod had good radiographic and clinical outcomes. In their treatment group they found
common risk factors for pseudarthrosis were smoking, weight >70 kg, and T5-T12
hyperkyphosis of > 40 degrees. They recommend consideration should be given to
alternate techniques in larger adolescents (>70 kg) with thoracic hyperkyphosis (>40
degrees ). The average coronal correction of thoracic curves was from 55 degrees to 29
degrees (47%). The average correction of thoracolumbar/lumbar curves was from 50
degrees to 15 degrees (70%). Neither of these variables were associated with
pseudoarthrosis. In the sagittal plane, lordosis was maintained in thoracolumbar/lumbar
fusions at -58 degrees (T12-sacrum). Improved maintenance of lumbar lordosis is
considered one of the advantages of an anterior approach.

In an additional study from the same group at Wash U, Hurford et al designed a study to
compare the results of anterior DUAL-rod instrumentation with their previous experience
using single-rod constructs. They found the two technique were comparable in the amount
of radiographic deformity correction obtained. However, they report the absence of any
pseudarthroses in the 60 patients with dual-rod is a distinct advantage over the single rod
technique.
16. A mother and her 16-year-old daughter present to your clinic because the daughter has
noticed asymmetries in her back. She has no back pain and no neurologic symptoms. She is
two years post-menarche. After a complete history and physical, you order PA
thoracolumbar radiograph, which is seen in figure A. The cobb angle is 38 degrees. When
discussing the natural history of the disease, you tell the family they should expect

1 difficulty with vaginal child birth in the future.

2 decreased pulmonary function in the future
3 to undergo an MRI to rule out any underlying neurologic
pathology, as this is an abnormal curve
4 an increased risk of chronic back pain over her lifetime
5 this curve magnitude has the highest curve progression
rate without operative intervention
Answer 4
• (AIS patent has an apex at T8, which makes this a main thoracic, Lenke type 1 curve.
While AIS is commonly referred to as a painless condition, Weinstein et al. published the
50-year follow-up, of 117 untreated patients with AIS compared to 62 age- and sex-
matched controls and found a statistically significant (p = 0.003) increase in chronic back
pain over 50 years.

Weinstein et al. they found that while there was an increase risk of chronic low back pain,
68% of the patients with scoliosis and low back pain reported mild or moderate
discomfort. Additionally, they found that there was only an increased risk of shortness of
breath in patients with a curve greater than 80 degrees.

In another study by the same group, they reported on the risk of curve progression over
40.5 years. They found that curves less than 30 degrees rarely progressed, and thoracic
curves measuring over 50 degrees were most likely to progress.

Danielsson and Nachemson reported on the effect of scoliosis, and scoliosis treatment on
women’s ability to bear children. They found no difference in rate of cesarean section
between women treated with surgery, a brace or a control group. They did find a slight
increase in the risk of having to have vacuum extractions in the surgery group compared
to either of the other two groups.
• Incorrect Answers:
Answer 1: Women who have scoliosis do not have an increased
risk of cesarean sections than those without scoliosis
Answer 2: Patients with a 38-degree curve do not have an
increased risk of pulmonary dysfunction.
Answer 3: The patient has a Lenke type 1, main thoracic curve.
No advanced imaging is needed
Answer 5: The patient is post-menarcheal by 2 years, and her
curve is 38 degrees. She has a low risk of curve progression
17. When compared to normal controls, adults with untreated idiopathic scoliosis and a
Cobb angle of greater than 60 degree at the time of skeletal maturity have a higher rate of
which of the following?

1 Acute and chronic back pain

2 Premature death
3 Disability
4 Clinical depression
5 Limitation in activities of daily living
Answer 1
• Weinstein et al (1981) looked at patients with untreated AIS. They found "many curves
continued to progress slightly in adult life, particularly thoracic curves that had reached
between 50 and 80 degrees at skeletal maturity. Backache was somewhat more common in
these patients than in the general population, although it was never disabling. Pulmonary
function was affected only in patients with thoracic curves."

Weinstein et al (2003) looked at patients with 50-year follow-up of patients with untreated
AIS (same cohort as prior study) and compared them with age/sex matched normal
controls. They found 61% of patients with AIS reported chronic back pain compared with
35% of controls (P =.003). However, the pain reported was only mild or moderate. There
was no statistically significant difference in disability, depression, age at death of patients,
and capacity to perform activities of daily living. They conclude untreated AIS causes little
physical impairment other than back pain and cosmetic concerns.