The low lumbar spine below Cotrel-Dubousset instrumentation - Long-term findings

Study Design. Retrospective review of long instrumented fusions down to the low lumbar spine for the treatment of adolescent idiopathic scoliosis. Objectives. To evaluate whether the use of instrumentation systems that pre serve the sagittal profile could reduce the incidence of early degenerative changes. Summary of Background Data, Long fusions and distractive Harrington instrum entation in the surgical treatment of adolescent idiopathic scoliosis (AIS) are known to produce pain and degenerative changes in the free lumbar segm ents. Reports on the use of Cotrel-Dubousett instrumentation (CDI) confirm that the instrumentation maintains physiologic lumbar lordosis, but the evo lution of the spine below the fusion is not addressed. Method. Thirty-five patients with AIS and CDI were studied. Their spines we re fused to L3 or lower, and they had a minimum follow-up of 10 years. Radi ologic measurements were recorded from frontal and lateral radiographs, At the time of last examination, lateral flexion-extension dynamic radiographs and magnetic resonance imaging evaluated the health of the disks below the fusion. Clinical outcome was assessed with the Scoliosis Research Society instrument, A control group consisting of 35 peers without scoliosis served as a reference for the outcome questionnaire. Results. Surgery kept the sagittal profile in a physiologic range. All but two patients were satisfied with the results of surgery. There were no diff erences between patients and control group insofar as pain, self-image, gen eral function, and daily activity were concerned. Eleven patients showed in stability signs in dynamic radiographs and more than half of patients showe d incipient degeneration on magnetic resonance images. These findings are s imilar to those found in the general population, according to the lireratur e, and could evidence normal aging processes. Conclusions. Cotrel-Dubousset instrumentation maintains the physiologic sag ittal contour. Although there are some degenerative changes in magnetic res onance images and dynamic radiographs, the quality of life and daily activi ties of the patients after surgery are similar to those of a normal populat ion of the same age.