Can Postoperative Radiographs Accurately Identify Screw Misplacements?

Area of Science:

• Spinal Surgery
• Radiology
• Orthopedic Devices

Background:

• Pedicle screw placement is critical for spinal fusion success.
• Postoperative radiographs are commonly used to initially assess screw placement.
• Computed tomography (CT) is often required for definitive screw safety evaluation.

Purpose of the Study:

• To evaluate the diagnostic accuracy of postoperative radiographs in assessing pedicle screw placement.
• To determine if radiographs are a safe and reliable method for screw assessment.

Main Methods:

• Retrospective review of 2,034 pedicle screws from 104 patients who underwent spinal fusion.
• Independent blinded observers assessed screw placement on radiographs using defined criteria.
• Musculoskeletal radiologist reviewed CT scans for definitive screw position assessment.

Main Results:

• Radiographic assessment showed low sensitivity (median 52%) and accuracy (median 68%) in identifying misplaced screws.
• Significant discrepancies were found between radiographic and CT interpretations for medial, lateral, and anterior screw misplacements.
• Radiographs frequently misclassified screw positions, with many screws deemed misplaced on X-ray being normal on CT.

Conclusions:

• Postoperative radiographs are a poor diagnostic tool for evaluating pedicle screw position.
• Reliance on radiographs alone can lead to misinterpretation of screw placement and safety.
• CT imaging remains essential for accurate assessment of pedicle screw placement after spinal fusion.