Idiopathic Scoliosis SPORC Mar 2017 Neil Saran, MD, MHSc, FRCSC
Objectives By the end of this session you will be able to 1. Recognize red flags in patients with scoliosis 2. List risk factors for progression in IIS 3. List risk factors for progression in AIS 4. List progression of AIS after skeletal maturity 5. Define a structural curve based on the Lenke classification
Infantile Juvenile Adolescent
Infantile Idiopathic Scoliosis Onset 0-3 yrs Ratio: M = F (1:1) Curve Pattern: Left Thoracic Associated findings: packaging disorders (plagiocephaly, torticollis, DDH, metatarsus adductus) 75-90% nonprogressive Upto 30% intrathecal pathology in this age group
Risk Factors for Progression in IIS Curve >25 o RVAD >20 o Phase 2 ribs
Predicting Progressive IIS RVAD is measured at Apical Vertebra JAAOS 2006 JBJS Br 1972
JBJS Br 1972 IIS RVAD 80% <20 o do not progress 80% >20 o progress Phase 2 ribs progress
IIS Treatment Serial Casting Mehta Cast Better prognosis when started before age 2 Cast Failures Growing rods with eventual fusion Delayed spinal fusion
Mehta JBJS B 2005 IIS 70% no scoli 11% surgery 19% scoliosis no surgery Not all patients in study have reached maturity
8 mos. 11 mos. 1 st cast 5 yrs 3 yrs post tx
Juvenile Idiopathic Scoliosis 4 9 yrs F>M 1.5-4.4:1 Mix of R and L Th curves 95% progress 80% will require SF 18-26% neural axis abnormality Chiari I, syrinx (cervical or thoracic), brainstem tumor, duralectasia, low conus
JIS - Treatment Bracing/Casting Growing Rods/Eventual Spinal Fusion Growth Modulation Delayed Spinal Fusion
Adolescent Idiopathic Scoliosis
Etiology Natural History History & Physical Radiography Bracing Fusion
Etiology Many theories Multifactorial with high genetic predisposition 27% of daughters of women with scoliosis will have a curve greater than 15o (ref 8) 11% prevalence in 1 st degree relatives (ref 2) 73% in monozygotic twins (ref 9) 36% in dizygous twins (ref 9) Risenborough et al JBJSA 1973 Harrington Clin Orthop 1977 Kesling and Reinker Spine 1097
Risk of Progression During Growth Age <19 o 20-29 o 30-39 o >40 o 10-12 25% 60% 90% 100% 13-15 10% 40% 70% 90% 16 0% 10% 30% 70% Risser 5-19 o 20-29 o 0,1 22% 68% 2,3,4 1.6% 23% Larger curves Younger skeletal age Thoracic curves 1. Nachemson AL, Lonstein JE, Weinstein SL. Report of the prevalence and natural history committee of the Scoliosis Research Society. Denver: Scoliosis Research Society, 1982. 2. Lonstein and Carlson. JBJS 1984
Risk of Progression After Maturity Thoracic curves <50 degrees are stable Thoracic curves 50-80 degrees tend to progress 0.75 o /yr Thoracolumbar/Lumbar curves >30 degrees tend to progress 0.5 o /yr Spine 1986 Weinstein JBJS 1981 Weinstein
Mortality Spine 1992
PFTs Curves >70 degrees can be associated with decreased PFTs Curves>100-110 o are associated with PFTs <45% PFTs <45% is associated with poor outcomes
PFTs Normal aging results in ~15% loss of PFTs (Kory, 1961) Suggesting that we should be targeting patients with PFTs in the 60-65% range rather than a specific curve severity. Larger curves and Thoracic Hypokyphosis predict poor PFT Spine 2011 Johnston et al
Diagnosing AIS Rule out other causes of scoliosis Congenital Neuromuscular Syndromic Mesenchymal Miscellaneous Olisthetic Tumor
History History Onset Progression Pain Radiculopathy Myelopathy Family History PMHx (cardiac / renal / GI / neuro) Developmental Milestones
Physical General Dysmorphic features Look at the feet (cavus) Gait Neuro Screening motor and sensory exam Deep tendon reflexes Abdominal cutaneous reflex Spine Midline defects Cutaneous lesions Coronal balance (<2cm) Rotational deformity (idiopathic scoliosis is a rotoscoliosis) Shoulder height Shoulder ROM Pelvic height
Abdominal Cutaneous Reflex (Video)
14F. Unilateral leg atrophy
10M
Osteoid Osteotoma
Radiography 51 24 44 Classic Patterns R Thoracic R Thoracic / L Lumbar L Thoracolumbar/Lu mbar
Radiography
Radiography Left sided Thoracic ABNORMAL in Adolescents
16 F
16 F
Spine 2003 AIS is a lordoscoliosis 75% of patients with syrinx will not have lordotic ribheads 97% of patients with normal MRI will have lordotic ribheads = MRI = MRI
JBJS 2001 Lenke
Bend films determine which curves (P, T, TL/L) are structural. Curves that bend to <25 are non-structural 51(22) 24(18) 44(13)
Bracing Indications: TRC open, R1, R2 + Scoliosis 25-40 o Boston TLSO For apices from T6-L3 20-22 hrs/day Charleston (night time only) For TL/L curves Providence (night time only)?t6 L3 Many others
2013 RCT and observational study Brace vs no brace 25% (brace) vs 58% (observation) failure (went on to require spinal fusion) Bracing is effective Bracing is dose dependent
Fusion in AIS Classical Dogma >45 o in a skeletally immature adolescent >50 o in a skeletally mature patient Levels Fuse all structural curves Try to avoid fusion below L3
Fusion Levels CSVL Central Sacral Vertical Line Apical Vertebra most rotated, most horizontal, most laterally deviated. End Vertebra most tilted Neutral Vertebra least rotated Stable Vertebra cephalad most vertebra at the caudal end of the curve that is best bisected by the CSVL
Fusion Levels PT UEV = T1/T2 Level shoulders UEV ~T2/3 L shoulder up UEV ~T1/2 MT UEV+1 to LT R shoulder up ~T4 or T5 TL/L EV to EV May try to cheat to L3 when LEV=L4 especially if L3 is level on the concave bend film EV = end vertebra UEV = upper end vertebra LEV = lower end vertebra LT = vertebra last touched by CSVL
What s New?! Vertebral Body Tethering (off-label) Based on the Hueter-Volkmann principle Compression inhibits the growth plate Tension stimulates the growth plate Tether the convex side of the spine No long term results Few short results
TRC Closed Risser 0 10 yo F 50 o curve
Take Home Message Idiopathic Scoliosis is a diagnosis of Exclusion Perform a proper History and Physical Carefully evaluate the radiographs AIS is a rotoscoliosis with apical lordosis AIS is not associated with increased mortality Bracing is effective Fusion is typically performed for curves that are expected to be >50 o at skeletal maturity in order to prevent late progression
Summary You should now be able to 1. Recognize red flags in patients with scoliosis 2. List risk factors for progression in IIS 3. List risk factors for progression in AIS 4. List progression of AIS after skeletal maturity 5. Define a structural curve based on the Lenke classification