Prevalence of Thoracic Hyperkyphosis in Patients with Adolescent Idiopathic Scoliosis

There are different classifications for adolescent idiopathic scoliosis (AIS), among which Lenke classification is the most recent and comprehensive method. It is 3 dimensional and treatment organized. In most previous studies, thoracic hypokyphosis was more common, but it may be different in many patients.
The current study aimed at assessing the prevalence of thoracic hyperkyphosis in AIS for the first time in Iranian population.
The study was performed retrospectively on 242 patients with AIS treated surgically in the university hospital from 2009 to 2014. Three parameters were evaluated in each patient including the 6 curve types of Lenke classification, thoracic sagittal balance, and lumbar spine modifier.
Adolescent idiopathic scoliosis was more common in female patients (83.5%). Type one curve was the most common type (48%). In lumbar spine modifier, type A was the most common (44%), similar to other studies. Hyperkyphosis was the most common type of thoracic sagittal balance (54%), which was in contrast to the original study by Lenke. The mean thoracic sagittal balance was hyperkyphosis in all Lenke types except type 5, which was normal. No relationship was found between the prevalence of thoracic kyphosis, and lumbar spine modifier, or the 6 types of Lenke classification.
The frequency of different types of curves in Iranian population was the same as that of the original article by Lenke except that in the current study more thoracic hyperkyphosis was observed than hypokyphosis in the population.