A New Perspective of Evaluation of the Relationship Between Spinal Pedicle Screw Malposition and Surgical Experience

Abstract

The computed tomography scans of patients who underwent posterior instrumentation for thoracolumbar vertebral fractures were retrospectively reviewed. The aim of this study is to present a single surgeon's experience in the placement of pedicular screws in the thoracic, lumbar, and sacral spine using the two-way fluoroscopy-assisted freehand technique. The directions of screw malposition were classified as anterior, medial, lateral, superior, and inferior; screws with malposition in more than one direction were recorded. Patients' neurological symptoms were recorded and their compatibility with the direction and amount of screw malposition was assessed. The effect of surgical experience on thoracic, lumbar, and sacral pedicle screw placement and the amount of screw experience required for correct pedicle screw placement were investigated. The study evaluated 1112 pedicle screws in 147 patients with thoracolumbar fractures. Screw malposition was found in 206 (18.52%) screws. Medial malposition was found to be statistically higher in the lumbar spine (p<0.001). A significant correlation was found between inferior malposition and neurological deficit (p=0.012). Thoracic and sacral pedicle screw malposition was statistically higher than lumbar (p<0.001). It was found that 386 pedicle screws were required for the learning curve in lumbar fractures (p=0.004). Surgical experience is an important factor in correct screw placement. It was found that 386 pedicle screws were required for the learning curve in the lumbar spine.

Keywords

• Thoraco-lumbo-sacral spine
• pedicular screw
• malposition
• learning curve

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