1. Thoracolumbar Kyphosis in Adolescents with Achondroplasia: Who Resolves and Who Progresses?
Tyler Kreitz MD
Oussama Abousamra MD
John Heydemann MD
William Mackenzie MD
Suken Shah, MD

2. Background TLK 50% children with achondroplasia1
Occurs early, resolves by age 3 in 60-70% 2,3
11-15% beyond age 10
neurologic symptoms requiring surgical intervention4,5
Risk factors for progression;
High TLK
Apical vertebral wedging
Developmental delay2,6

3. Purpose
To define spinopelvic in children with achondroplasia and determine if these parameters may be predictive of persistent progressive TLK in children with achondroplasia

4. Methods 300 children 2004-2015 Minimum 2 year radiographic follow-up
One standing lateral radiograph after age 10
Excluded postoperative radiographs
Measured:
Thoracolumbar kyphosis (T10/L2),
Thoracic Kyphosis, Lumbar Lordosis, Pelvic Incidence (PI)

5. Methods Two groups identified; Final TLK ≥20 or <20 degrees
Outcomes:
Evolution of measurements within each group
Comparison to detect potential risk factors for a high TLK after ten years of age.

6. Results
64 children
22 (31%) had TLK ≥20. Mean age at the first and last evaluations was 10.8 and 16.7 years
None of their measurements changed significantly over a mean followup 5.9 years ( years) except for TPA and SVA that were in clinically acceptable limits.
44 (69%) had TLK <20. Age at the first and last evaluations was 8.2 and 14.2 years. TLK was the only parameter that changed significantly (decreased) over a mean of 6 years ( years).

7. Results
TLK ≥2: No measurements changed over mean followup 5.9 years ( )
TLK <20: TLK only parameter that changed (decreased) over mean 6 years (2-10.1).

8. Results
A comparison between the two groups showed that for children who had a high final TLK, initial TLK was significantly higher and PI was significantly lower.

9. Conclusions
After ten years of age, TLK did not show improvement over time. Lower PI was associated with high TLK.
Emphasizes the importance of early radiographic follow up for thoracolumbar deformity in children with achondroplasia. Once children have increased TLK after age ten, the deformity is likely to remain, and assessment of pelvic parameters is important.

10. References
Engberts AC, Jacobs WCH, Castelijns SJAM, Castelein RM, Vleggeert-Lankamp CLA. The prevalence of thoracolumbar kyphosis in achondroplasia: a systematic review. J Child Orthop. 2012;6(1): doi: /s
Kopits SE. Thoracolumbar kyphosis and lumbosacral hyperlordosis in achondroplastic children. Basic Life Sci. 1988;48:
Borkhuu B, Nagaraju DK, Chan G, Holmes LJ, Mackenzie WG. Factors related to progression of thoracolumbar kyphosis in children with achondroplasia: a retrospective cohort study of forty-eight children treated in a comprehensive orthopaedic center. Spine. 2009;34(16): doi: /BRS.0b013e3181ac8f9d.
Pauli RM, Breed A, Horton VK, Glinski LP, Reiser CA. Prevention of fixed, angular kyphosis in achondroplasia. J Pediatr Orthop. 1997;17(6):
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