Use of computed tomographic reconstruction to establish the ideal entry point for pedicle screws in idiopathic scoliosis

Abstract

To determine the ideal entry point for individual pedicle screw in the surgical treatment of idiopathic scoliosis using computed tomographic (CT) three-dimensional (3D) reconstruction. Twenty patients with moderate or severe idiopathic scoliosis from two groups received surgical treatment using "Free Hand technique" and "Assisted Free Hand technique". Computed tomographic scanning with 3D reconstruction of the thoracic and lumbar spine was conducted to determine the entry point and to evaluate the placement accuracy. The accuracy of placement was 88.2% in convexity and 84.5% in concavity for the "Free Hand" group, and 94.1% in convexity and 94% in concavity for the "Assisted Free Hand" group. Evidence showed that "Assisted Free Hand" group had higher accuracy when screws were placed in the thoracic spine (P=0.02), while no obvious difference was seen in the lumbar spine placement (P=0.47). We conclude that in the surgical treatment of severe scoliosis, individual screw placement guided by entry points determined by CT reconstruction can result in improved accuracy and ease of the procedure.