The use of pedicle screw fixation to improve correction in the lumbar spine of patients with idiopathic scoliosis - Is it warranted?

Study Design. A retrospective assessment of coronal, sagittal, and axial correction using convex lumbar pedicle screw constructs compared with hook constructs in patients with idiopathic scoliosis. Objective. To determine if pedicle screw constructs can improve coronal, sagittal, and axial correction without increased complications and therefore warrant their use in the lumbar spine. Summary of Background Data. Although hooks have been the traditional fixation choice for posterior scoliosis correction of the lumbar spine, pedicle screws may offer advantages for improved correction of lumbar spinal deformity. Methods. Twenty-two patients constituted Group A (hooks), in which 17 were double major and five were King Type IV curves. These patients had a minimum follow-up period of 2 years and an average of one hook per lumbar fusion segment. Twenty-two patients constituted Group B (screws), in which 20 were double major and two were King Type IV curves. These patients had a minimum follow-up period of 2 years, and screw configuration consisted of pedicle fixation on the convex side for correction and at times on the concave side for fixation. Results. Pedicle screw fixation constructs had improved lumbar Cobb correction (P < 0.05), lowest instrumented vertebra tilt (P < 0.05), lowest instrumented vertebra translation (P < 0.01), and segmental sagittal alignment from T12 to lowest instrumented vertebra (P < 0.01). There was no significant change in axial rotation using either surgical method. Conclusions. The use of pedicle screw fixation on the convex portion of the lumbar spine in patients with double major idiopathic scoliosis allows for improved correction of the lumbar Cobb measurement, horizontalization and translation of the lowest instrumented vertebra, and improved segmental lordization over the instrumented levels without increased complications.