Summary:To assess the clinical efficacy of promoted changes in second-generation segmental instrumentation technology, we performed a retrospective analysis of 42 consecutive patients requiring posterior spinal fusion for adolescent idiopathic scoliosis. Cotrel-Dubousset instrumentation (CDI) was used in 24, and Texas Scottish Rite (TSRH) Universal Spine instrumentation was used in 18. There was no statistically significant difference between systems with regard to correction, operative time, estimated blood loss, postoperative decompensation, thoracic correction in the sagittal plane (8.1° for CDI, 7.2° for TSRH), or maintenance of lumbar lordosis. The results emphasize similarities rather than differences between the two systems. Poor curve correction and maintenance were due primarily to errors in strategy or application rather than failure of the systems.