Published in:
01-04-2012 | Original Article
Is the fluoroscopic view enough for accurate percutaneous sacroiliac screw insertion? An experimental study
Published in: European Journal of Orthopaedic Surgery & Traumatology | Issue 3/2012
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Objective
To evaluate the limits of the inlet, outlet and lateral fluoroscopic views in optimising percutaneous sacroiliac screw insertion and to find the method to avoid the screws misplacement.
Methods
In a simulated surgical procedure, 4 pelvic specimens were used for the insertion of 8 cannulated screws into the S1 vertebral bodies and perforated from the other side of sacral ala slope. The exit point was defined as the middle point of the other side of sacral ala curve. All perforation length was designed as 5 mm. The postoperative X-ray of the screw position was performed with visual examination, postoperative X-ray and computed tomography (CT).
Results
In the X-ray inlet view, the screw tip was approximately located at the junction of the anterior 1/4 and posterior 3/4 of the sacral ala. In the outlet view, the screw tip was approximately located at the junction of the upper 1/5 and lower 4/5 of the sacral ala. In the lateral view, the screw was located at the posterior of the alar slope image.
Conclusion
If the screw tip located in the anterior 1/4 of sacral ala on the inlet view and in the superior 1/5 of sacral ala on the outlet view, the screw tip possibly has already perforated the anterior cortex. It is important to properly adjust the direction of the screw or decrease the length of the screw for safe placement of the sacroiliac screw.