Abstract
Purpose of the study
We propose a simple classification for adolescent idiopathic scoliosis (AIS) based on two components which include the curve type and shoulder level and suggest a treatment algorithm for AIS.
Introduction
Few Classification systems for adolescent idiopathic scoliosis (AIS) have helped in communicating, understanding and selecting a treatment for this condition; however, most of these classifications are complex and include many subtypes, making it difficult for the orthopaedic surgeon to use them in clinical practice. The variable reliability and reproducibility of these studies make recommendations and comparisons between various operative treatments a difficult task. Furthermore, none of these classifications has taken the shoulder imbalance into account, despite its importance as a clinical parameter and outcome measure.
Methods
We developed a classification system with two components: curve type (I through III) and shoulder level (A or B). The curve types are divided into type I: Primary lumbar-thoracolumbar +/− secondary dorsal; type II: Primary dorsal secondary lumbar and type III: Dorsal. Each curve pattern is subdivided into type A or B depending on the shoulder level. In type A, the lower shoulder is ipsilateral to the concavity of the primary curve. In type B, the shoulders are level or the lower shoulder is on the convexity of the primary curve. This classification was tested for interobserver reliability and intraobserver reproducibility by six surgeons using radiographs of 28 patients. We performed a retrospective analysis of the radiographs of 232 consecutive AIS cases to assess the prevalence of curve types and tested the surgical treatment against the proposed treatment algorithm.
Results
Three major types and six subtypes were identified, of which type I accounted for 30%, type II 28% and type III 42%. The kappa coefficient for interobserver reliability was 0.943, while the kappa value for intraobserver reproducibility was 0.964. There was a complete concordance with the shoulder level component. Of the 232 cases reviewed, with a minimum two-year follow-up, only three patients developed a decompensation distal to the instrumentation requiring fusion extension.
Conclusion
This classification is the first of its kind to specifically address shoulder imbalance in the surgical decision-making process. The high interobserver reliability and intraobserver reproducibility is due in part to the simplicity of this classification, which makes it an invaluable tool to describe scoliosis curves and offers a potential treatment algorithm in correcting scoliosis.
Conflict of interest statement: None.
Ethics: Audit/service standard in trust.
