Comparison of thoracic pedicle screw to hook instrumentation for the treatment of adult spinal deformity

Study Design. Retrospective, case-control, matched cohort. Objective. Compare the radiographic and clinical outcomes of adult spinal deformity patients treated with thoracic pedicle screw (TPS) or thoracic hook constructs. Summary of Background Data. The efficacy of TPS instrumentation for pediatric spinal deformity correction has been established. Little is known about TPS use in adult spinal deformity. Methods. Fifty-six patients (average age, 49 years; average follow-up, 3.58 years) were treated with TPS or thoracic hook constructs for coronal (n = 20) or sagittal (n = 36) plane deformities. Patients were evaluated radio-graphically and with SRS scores. Results. Coronal deformities treated with TPS demonstrated improved main thoracic curve correction compared with hook constructs at last follow-up (24.8 vs. 13.8; P < 0.05), despite having larger (59.8 vs. 44.9; P < 0.05) and more rigid preoperative curves (29.3% vs. 44.9% correction on side-bending radiographs; P < 0.001). Sagittal deformities treated with TPS constructs demonstrated greater thoracolumbar kyphosis correction than hook constructs at last follow-up (12.1 vs. 2.5; P < 0.05). No TPS patient had a thoracic pseudarthrosis. Four hook patients (14%) had thoracic pseudarthroses. Conclusions. TPS instrumentation allows greater coronal and sagittal plane correction and may reduce the risk of thoracic pseudarthrosis compared with hook constructs when treating adult spinal deformities.