Introduction: Thoracolumbar kyphosis (TLK) is a common presentation in children with achondroplasia, but the prevalence has not been reported. Persistent TLK in combination with the narrow spinal canal in achondroplasia increases the chance of spinal cord compression. Therefore, the objective of this study is to investigate the prevalence of TLK in children and the treatment options in reducing the deformity.
Methods: Lateral radiographs of the thoracolumbar spine in 60 children ( < 4 years) were retrospectively evaluated for the presence of TLK (Cobb angle ≥ 20 degrees between T10 - L2). Development of TLK during follow up was compared in separate treatment groups: expectant non-bracing therapy, bracing therapy, and surgical correction. Resolution of TLK was defined as a Cobb angle < 20 degrees at final follow up.
Results: The prevalence of TLK in children with achondroplasia at a median age of 10.5 (IQR 7.0 - 20.5) months was 85.0%. The mean Cobb angle in patients with TLK significantly decreased from 33.7 ± 11.0 degrees at baseline to 25.0 ± 17.7 degrees (p < 0.001) after a median follow up of 1.9 (IQR 0.8 – 3.3) years. Resolution of TLK occurred in 43.6% of patients, 48.7% of patients developed persistent TLK with stable follow up and 7.7% of patients underwent surgery due to onset of neurological symptoms. There was no significant difference in the reduction of TLK between bracing therapy and expectant non-bracing therapy (p = 0.148). Bracing was however significantly more effective (p < 0.001) in a subgroup (N = 16) of patients with severe TLK (Cobb angle ≥ 40 degrees).
Conclusion : The observed high prevalence of TLK in achondroplasia amplifies the importance of studying the development and treatment. Expectant non-bracing therapy is the first-choice treatment option, although bracing therapy should be considered- and started early for patients with a Cobb angle ≥ 40 degrees.
