Lenke classification system of adolescent idiopathic scoliosis: treatment recommendations

The Lenke and associates classification system of adolescent idiopathic scoliosis (AIS) was developed to provide a comprehensive and reliable means to categorize all surgical AIS curves. This classification system requires analysis of the upright coronal and sagittal radiographs along with the supine side bending radiographic views. The triad classification system consists of a curve type (1-6), a lumbar spine modifier (A, B, C), and a sagittal thoracic modifier (-, N, +). All three regions of the radiographic coronal and sagittal planes, the proximal thoracic, main thoracic, and thoracolumbar/lumbar are designated as either the major curve (largest Cobb measurement) or minor curves with the minor curves separated into structural and nonstructural types. The recommendations are that the major and structural minor curves are included in the instrumentation and fusion and the nonstructural minor curves are excluded. Overall, the classification system is treatment directed; however, there are other aspects of the radiographic and clinical deformity that may suggest deviation from the recommendations of the classification system. The ultimate goal of this classification system is to allow organization of similar curve patterns to provide comparisons of various treatment methods to provide optimal treatment for each AIS surgical patient.