Ability of Cotrel-Dubousset instrumentation to preserve distal lumbar motion segments in adolescent idiopathic scoliosis.

Between 1985 and 1990, 44 patients with adolescent idiopathic scoliosis were treated with Cotrel-Dubousset instrumentation when Harrington instrumentation would have extended into the distal lumbar spine (L3, L4, or L5) for these curve patterns. Twenty-four of these 44 (group I) patients had one distal fusion level preserved using Cotrel-Dubousset instrumentation, whereas the other 20 patients (group II) were instrumented/fused with Cotrel-Dubousset instrumentation to the expected Harrington instrumentation level in the lower lumbar spine. All patients have a minimum 2-year follow-up, and the average follow-up is 39 months (range 24-74). The characteristics of the group I curves that allowed us to stop the instrumentation a level short included minimal rotation and tilt of the anticipated lowest instrumented vertebra, overall coronal curve flexibility, and nonstructural components to the lumbosacral region of the spine. There were no major differences between these two groups when comparing postoperative coronal and sagittal balance parameters at the most recent follow-up. In select cases, dependent on the preoperative criteria to be discussed, Cotrel-Dubousset instrumentation (vs. traditional Harrington instrumentation) does allow distal lumbar fusion levels to be saved while maintaining acceptable coronal and sagittal balance.