Accuracy of Computer Assisted Percutaneous Placement of Hiosacral Screws: A Cadaveric Study

Abstract

Objective: To determine the accuracy of computer-assisted fluoronavigation for percutaneous iliosacral screw placement.

Materials and Methods: A fluoronavigation system (Stryker Navigation System, Stryker Leibinger, Kalamazoo, MI) was used to guide the placement of four iliosacral screws into the S-1 bodies of each of five cadaveric pelvic specimens with intact soft tissues. Accuracy of screw placement was verified by radiographs, CT scans, and direct dissection.

Results: All 20 screws were placed accurately without complications. Nineteen screws were completely contained within the osseous “safe zone.” On direct dissection, one screw was noted to have penetrated the S-1 foramina by 3 mm without impingement on the nerve root. This was not detected on radiograph or CT scan.

Conclusion: The results of this study support the safety and accuracy of computer-assisted fluoronavigation for iliosacral screw placement. The advantages include decreased fluoroscopic time, real-time simultaneous visualization of all three views (inlet, outlet, and lateral), and increased accuracy of placement. Clinical study is warranted.

Key Words:

• iliosacral screws
• percutaneous placement
• computer assisted imaging
• fracture fixation