Spinal pedicle fixation. Confirmation of an image-based technique for screw placement

Area of Science:

• Spinal Surgery
• Orthopedic Surgery
• Surgical Techniques

Background:

• Pedicle screw insertion is crucial for spinal fusion but carries a risk of pedicle cortex perforation.
• Current techniques require precise identification of entry points, angulation, pilot hole preparation, and depth control.
• Unacceptable perforation rates necessitate improved methods for accurate pedicle screw placement.

Purpose of the Study:

• To evaluate the accuracy of a novel pedicle screw insertion technique using angled posteroanterior image intensification.
• To determine the incidence of pedicle perforations with this specific technique in a cadaveric model.

Main Methods:

• Ninety pedicle screws were inserted into human cadaveric lumbar spines.
• A technique utilizing posteroanterior image intensification angled in the pedicle axis guided entry point identification and insertion.
• Specimens were dissected and examined visually and palpatorily to assess screw placement accuracy.

Main Results:

• Overall pedicle perforation rate was 5.5% (5 out of 90 screws).
• Malpositioning accounted for 3.4% of perforations, while pedicle/screw size discrepancy caused 2.1%.
• The incidence of malpositioning-related perforations was lower than previously reported rates.

Conclusions:

• The proposed technique using angled image intensification may improve pedicle screw placement accuracy.
• This method has the potential to reduce pedicle perforation rates in spinal surgery.
• Further in vivo studies are needed to validate these findings in a clinical setting.