Results of Spinal Instrumentation of Adolescent Idiopathic Scoliosis by King Type

The purpose of this study is to determine the usefulness of the King classification in predicting decompensation in adolescent idiopathic scoliosis. Fifty-one patients were reviewed with a mean follow-up of 25 months. Five patients had Type 1 adolescent idiopathic scoliosis: four were treated with Zielke/Cotrel-Dubousset instrumentation or Zielke instrumentation alone. Correction was greater than 51% in these cases and there was no decompensation. Twenty-three patients had Type II scoliosis. Nineteen of whom were treated with Cotrel-Dubousset instrumentation; 3 with Zielke and Cotrel-Dubousset instrumentation, and 1 with Zielke. The best correction occurred with anterior/posterior instrumentation. Decompensation occurred in 9 patients, all of whom were treated with Cotrel-Dubousset instrumentation alone. Fourteen patients had Type III scoliosis. All were treated with Cotrel-Dubousset instrumentation with correction of 65%. Decompensation occurred in 4 patients, all of whom were fused to or beyond the stable vertebra. Four patients had Type IV scoliosis; all were fused short of the stable vertebra with Cotrel-Dubousset instrumentation, resulting in correction of 52% and no decompensation. Five patients had Type V instrumentation; four were treated with Cotrel-Dubousset instrumentation and 1 with Zielke. There was no relationship between level of fusion and decompensation. Based on this study, the authors contend that the King classification is a valuable tool in the selection of type of instrumentation and fusion level.