congenital scoliosis
TRANSCRIPT
ClassificationDefects of Segmentaion
Defects of FormationComplex Spine Deformities
• Proposed by Moe et al– Early concept
• Van Schrick• Mac Ewen
• Accepted by SRS and AAOS• Simplistic
– Ignores current understanding of embryogenesis– Does not explain all deformities
Tsou et al, Clinical Ortho and Related Research, No. 152, 1980
Embryonic Period Anomalies1st 56 Days
• Germinal layer adhesion• Notochord substance sequestration• Asynchronous hemimetameric pair
development• Hemimetamer hypoplasia and aplasia• Ventral and lateral process coalition
Tsou et al, Clinical Ortho and Related Research, No. 152, 1980
Tsou et al, Clinical Ortho and Related Research, No. 152, 1980
Hedequist and Emans, Congenital Scoliosis, Journal of AAOS, 2004
Tsou et al, Clinical Ortho and Related Research, No. 152, 1980
Fetal Period Anomalies57th day to Birth
• Vertebral joint failure of segmentation• Centrum hypoplasia and aplasia
Tsou et al, Clinical Ortho and Related Research, No. 152, 1980
Tsou et al, Clinical Ortho and Related Research, No. 152, 1980
Tsou et al, Clinical Ortho and Related Research, No. 152, 1980
Tsou et al, Clinical Ortho and Related Research, No. 152, 1980
Tsou et al, Clinical Ortho and Related Research, No. 152, 1980
Tsou et al, Clinical Ortho and Related Research, No. 152, 1980
Tsou et al, Clinical Ortho and Related Research, No. 152, 1980
Lonstein, Congenital Spine Deformities, Ortho Clinics of NA, Vol 30, No.3, 1999
Genetics• Wynne-Davies 1975
– 337 pts with congenital anomalies– Most were sporadic with no risk to subsequent siblings of
offspring– Multiple anomalies carried a 5~10% risk to sibs
• Winter 1983– 1200 pts– 1% with a known relative with a problem
• Most twin studies show one with a defect and one without• McMaster et al JBJS, 1999,
– Positive family hx with multiple levels of bilateral failure of segmentation, fused ribs, missing segments
– Spondylothoracic dysplasia or Jarcho-Levin syndrome
Associated Anomlies• Renal 30% - Renal imaging is most important
image in pre-schoolers• Cardiac 15% - Evaluate murmurs, they are never
due to the scoliosis• Dysraphism 20+%
– Beware of skin anomalies– Leg length discrepancy– Neurological asymmetry
• Skeletal anomalies
Hedequist and Emans, Congenital Scoliosis, Journal of AAOS, Vol 12, No. 4, 2004
Nomenclature• Segmented – has disc space• Incarcerated – adjacent level accommodates
hemi
Hedequist and Emans, Congenital Scoliosis, Journal of AAOS, Vol 12, No. 4, 2004
Midline Ectodermal Anomalies Correlate with Neural Anomalies
• Skin tag• Dimples• Pigmentation• Hair patch
Hedequist and Emans, Congenital Scoliosis, Journal of AAOS, Vol 12, No. 4, 2004
Midline skin anomalies may mean neural anomalies
Hedequist and Emans, Congenital Scoliosis, Journal of AAOS, Vol 12, No. 4, 2004
Evaluation of Entire Spinal Canal• Search for anomalies
– Chiari malformation– Syringomyelia– Diatematomyelis– Filum terminale– Lipoma– Tumor
• Indication– Pre-op– Neurologic deficit or asymmetry– Lower limb asymmetry– Every pt with a congenital defect?
Hedequist and Emans, Congenital Scoliosis, Journal of AAOS, Vol 12, No. 4, 2004
Diastematomyelia
Diastematomyelia Radiographic Signs
• Widened interpedicular distance• Narrowed disc• Midline calcification
Winter Sign Asymmetrical forward bend is consistent with
a tethered cord
Tethered Cord Not Just a Problem for Children• Adults can present with tethered cord symptoms
– Increasing pain or neurologic loss of function– Lower limb asymmetry or spasticity
• Do not be satisfied with images of only lumbar spine
Lonstein, Congenital Spine Deformities, Ortho Clinics of NA, Vol 30, No.3, 1999
Hedequist and Emans, Congenital Scoliosis, Journal of AAOS, Vol 12, No. 4, 2004
Progression of Congenital Scoliosis
• Highly variable• “Most progress” (10~20% nonprogressive)
– Unilateral bar with contralateral hemi – worst– Unilateral unsegmented bar– Double hemivertebra– Single hemivertebra– Wedge vertebra– Block vertebra – best prognosis
McMaster and Ohtsuka,JBJS, vol 64, 1982
Location
• Thoracic curves with poorest prognosis• Hemivertebra at lumbosacral and
cervicothoracic junction cause decompensation
Lonstein, Congenital Spine Deformities, Ortho Clinics of NA, Vol 30, No.3, 1999
Non-operative Treatment• Observation
– Not for high risk– Hemivertebra and mixed deformity
• Bracing – limited role– Contraindicated for short stiff curves– ? Help for flexible curves
Lonstein, Congenital Spine Deformities, Ortho Clinics of NA, Vol 30, No.3, 1999
Treated with Observation
Hedequist and Emans, Congenital Scoliosis, Journal of AAOS, Vol 12, No. 4, 2004
Surgical Rx
• Fusion-in-situ– Simple– Ineffective
• Anterior epiphysiodesis & posterior hemiarthrodesis– Progressive deformity– Growing patient
• Combined anterior posterior fusion• Hemivertebra excision
Lonstein, Congenital Spine Deformities, Ortho Clinics of NA, Vol 30, No.3, 1999
Convex Growth Arrest at 2+8
Hedequist and Emans, Congenital Scoliosis, Journal of AAOS, Vol 12, No. 4, 2004
Lonstein, Congenital Spine Deformities, Ortho Clinics of NA, Vol 30, No.3, 1999
Ant excision of hemivert and post instrumentation and fusion
Congenital Scoliosis with Myelodysplasia
Rx with ant discectomies post instr with pedicle screws at bifid vertebra and Galveston fixation
Kyphosis• Kyphosis with centrum aplasia
– Sharp angular– Risk of paraplegia– Rx with circum-fusion +/- corpectomy
• Kyphosis with anterior bar– Less neuro risk id not operated– Surgical options customized
Lordosis • Anterior fusion – small curve• Anterior / posterior procedure – large
curves
Lonstein, Congenital Spine Deformities, Ortho Clinics of NA, Vol 30, No.3, 1999
Progressive lordosis treated with ant discectomies, post fusion, and post-op cast
Lonstein, Congenital Spine Deformities, Ortho Clinics of NA, Vol 30, No.3, 1999
Conclusion
• Embryogenesis can be analyzed• Progression is unpredictable with exceptions
– Bar with contralateral hemivertebra– Kyphosis due to centrum aplasia
• Treatment – Remove deforming growth elements– Fusion-in-situ is no better than placebo