STUDY DESIGN: A retrospective review of data prospectively entered into a multicenter database. OBJECTIVE: To evaluate the adherence to classification-specific surgical treatment recommendations for adolescent idiopathic scoliosis (AIS) before and after the Lenke classification system introduction in 2001. SUMMARY OF BACKGROUND DATA: The Lenke classification system of AIS was developed in 2001 to provide a comprehensive and reliable means to categorize and guide treatment. The treatment recommendations of the system state that major and structural minor curves are included in the instrumentation and fusion and the nonstructural minor curves are excluded. METHODS: Surgical AIS cases for each Lenke classification (curve types 1-6) were queried for "Rule-breakers," in which the treatment performed did not follow the recommendations of the Lenke classification system. Each "Rule-breaker" case was individually evaluated to ensure correct Lenke classification and radiographic image verification was performed. "Rule-breaker" patients were expressed as a percentage of the total number of patients for each curve type. The presence of "Rule-breakers" before and after the introduction of the Lenke classification system in 2001 was evaluated for statistical difference using a chi-square analysis. RESULTS: The data for 1310 AIS patients who underwent surgical correction for their deformity were included in this analysis. Overall, treatment of 191 patients did not follow the classification recommendations; the rules are broken 15% of the time. The proportion of "Rule-breakers" (18%) was significantly greater prior to the introduction of the Lenke classification system than it was after (12%) (P=0.001). CONCLUSION: The introduction of this system has led to a reduction in the variation of treatment approaches; however, our data suggest that 6% to 29% of the time, depending on the curve pattern, there are other aspects of the clinical and radiographic deformity that suggest deviation from the recommendations of the classification system. The outcome of adherence to this system remains yet to be evaluated.
STUDY DESIGN: A retrospective review of data prospectively entered into a multicenter database. OBJECTIVE: To evaluate the adherence to classification-specific surgical treatment recommendations for adolescent idiopathic scoliosis (AIS) before and after the Lenke classification system introduction in 2001. SUMMARY OF BACKGROUND DATA: The Lenke classification system of AIS was developed in 2001 to provide a comprehensive and reliable means to categorize and guide treatment. The treatment recommendations of the system state that major and structural minor curves are included in the instrumentation and fusion and the nonstructural minor curves are excluded. METHODS: Surgical AIS cases for each Lenke classification (curve types 1-6) were queried for "Rule-breakers," in which the treatment performed did not follow the recommendations of the Lenke classification system. Each "Rule-breaker" case was individually evaluated to ensure correct Lenke classification and radiographic image verification was performed. "Rule-breaker" patients were expressed as a percentage of the total number of patients for each curve type. The presence of "Rule-breakers" before and after the introduction of the Lenke classification system in 2001 was evaluated for statistical difference using a chi-square analysis. RESULTS: The data for 1310 AISpatients who underwent surgical correction for their deformity were included in this analysis. Overall, treatment of 191 patients did not follow the classification recommendations; the rules are broken 15% of the time. The proportion of "Rule-breakers" (18%) was significantly greater prior to the introduction of the Lenke classification system than it was after (12%) (P=0.001). CONCLUSION: The introduction of this system has led to a reduction in the variation of treatment approaches; however, our data suggest that 6% to 29% of the time, depending on the curve pattern, there are other aspects of the clinical and radiographic deformity that suggest deviation from the recommendations of the classification system. The outcome of adherence to this system remains yet to be evaluated.