Idiopathic Scoliosis - CHU Sainte-Justine - SAAC

Idiopathic Scoliosis
Update in management in 2012
Stefan Parent, MD, PhD.
Academic Chair in Pediatric Spinal
Deformities of CHU Ste-Justine
SPORC 2011

Idiopathic Scoliosis
• Affects 2-3% of the population
• The most common form is adolescent idiopathic scoliosis
• Affects primarly adolescent females
• Still remains of uncertain etiology
• Genetic factors
• Hormonal factors
• Abnormal biomechanical forces
• Connective tissue abnormalities
• Neuro-physiologic predisposition

Prevalence
• 0.5-3% for curves greater than 10°
• 1.5 – 3 per 1000 for curves greater than 30°
• Small to moderate curves are common
• Severe curves requiring treatment are rare
• Boys and girls equally affected for minor curves
• Larger curves: girls:boys = 8:1

Etiological factors
JBJS A 2000; Lowe et al.

Known progression factors
• Age (skeletal maturity)
• Sex
• Initial Cobb angle
• Peak growth velocity
• Family history

Age
• AKA skeletal maturity
• Tri-radiate cartilage closure
• Risser sign
• Menarchal status
Menses usually start 6-12 months after peak
growth velocity

Copyright © restrictions apply.
Plot of height velocity curve with median occurrence of menarche, age at menarche plus two years,
and Risser grades 1, 4, and 5 in the 120 female patients with idiopathic scoliosis
Little, D. G. et al. J Bone Joint Surg Am 2000;82:685

• Rapid acceleration phase in AIS corresponds to
time between Risser 0 with triradiate cartilage
closed and Risser 1.

Incidence of curve progression based on age at presentation
and curve size
Lonstein JE, Carlson JM. JBJS (A) 1984

Treatment options
• Observation
• Brace treatment
• Surgical treatment

Yes
Patient presenting with scoliotic curve
11 - 25 ° 25 - 45 ° > 40-50
Skeletal maturity °
Skeletal maturity
No
Yes No
Consider Surgical
intervention
F-U
PRN
F-U until
skeletal maturity
every 6-12
months
F-U every 5
years to assess
progression
Consider bracing
F/U q4-6 months
Adapted from Parent, Newton et al. ICL 2005

Observation
• Usually reserved for mild curves (less than 20°)
• Mild to moderate curve at physical maturity
(below 40°)
• Patient preference

Lorenz, circa 1920
Hippocrates (460-377 BC)
Conservative
Treatment !!
Le Mesurier, 1940
Cotrel, 1960

Bracing
• In growing children (pre-teen and adolescents)
• Documented curve progression to 25-30° (SRS)
• Different types
• Problems with compliance
• Prevents 90% of curves from progressing when
worn > 16 hours
• Allington et al. JBJS(A) 1996 and Green JBJS(A) 1986
• Not practical after skeletal maturity

Bracing
• Thoraco-lumbo-sacral orthosis (TLSO)
• Several types available
• Boston underarm brace most popular among North
American surgeons for adolescent idiopathic scoliosis
• Must be worn at least 16 hours/day to have an effect
• Effective for double major curves and simple thoracic
and lumbar curves
• Not as effective for high thoracic curves

Boston Brace

Bracing
• Nighttime bending braces
• Charleston and Providence designs
• Work by overcorrecting the spinal deformity
• Probably as effective in preventing progression in
single lumbar and thoraco-lumbar curves as Boston
brace
Howard et al. Spine 1998
• Boston brace found to be more effective for other
types of curves than nighttime bending brace
Howard et al. Spine 1998 and Katz et al. Spine 1997

Price C et al, Nighttime bracing for AIS with the Charleston bending brace:
long term follow-up, JPO, 17:703-707, 1997

Surgery
• Goal is to improve spinal balance and alignment and
prevent further progression
• Indications based on:
• Curve magnitude (usually > 40-50°)
• Clinical deformity (rib prominence)
• Skeletal maturity
• Curve pattern
• Risk for progression

Indications for surgical treatment
• During growth
• Curve > 45-50%
• Progressive thoracic deformity
• Trunk imbalance
• Failed brace treatment
• After end of growth
• Curve > 50%
• Progressive deformity
• Intractable pain

Current trends in surgery
• Fuse short and instrument a lot!!!
• Increasing posterior vs. Decreasing anterior
• Segmental instrumentation provides better curve
correction
• Thoracic pedicles screws are « state-of-the-art »
• Thoracoscopic procedures have re-defined role

Surgery Goals
• Balanced spine
• Avoid fusing unnecessary levels
• Provide long-term pain relief
• Improve cosmesis
• Prevent cardio-pulmonary decompensation

Thoracoscopic procedures
• Thoracoscopic anterior release and fusion
• Reserved for curves between 70° to 100°
• Under 70°, use posterior approach only
• Over 100°, anterior release through open
thoracotomy
• Thoracoscopic anterior scoliosis instrumentation + fusion
• Provides good cosmetic results in selected patients
• Long and steep learning curve
• Potentially less damage to the chest wall musculature
than open approach and avoids damage to paraspinal
musculature

Thoracoscopic Exposure

Discectomy/Fusion

New strategies for correction
• Direct vertebral derotation (DVD)
• VCM (Vertebral column manipulation)
• Direct apical vertebral derotation (DAVD)
• All based on the correction of thoracic
deformity using pedicle screw anchors

Minimally Invasive surgery
• New trend in deformity
surgery
• Long instrumentation
now possible through
small incisions
• Fusion relies on facet
fusion
• Long-term outcome

Minimally invasive treatment
Courtesy F. Miyanji

Summary
• Scoliosis remains of uncertain etiology
• Curve progression is difficult to assess
• Treatment options include observation, bracing
and surgery

Summary
• Bracing to prevent progression
• Different types of orthoses available
• Surgery to correct spinal deformity and obtain
balanced, pain-free spine