Perpendicular probing and screwing technique: A simple method for accurate pedicle screw placement based on the human...

Area of Science:

• Orthopedics
• Spinal Surgery
• Surgical Techniques

Background:

• Pedicle screw (PS) placement is crucial for spinal fixation surgery.
• Malpositioned pedicle screws can lead to critical complications.
• Accurate trajectory assessment is paramount for safe and effective PS placement.

Purpose of the Study:

• To demonstrate the accuracy and safety of a simple, cost-effective PS placement technique.
• To evaluate a novel method using an internal reference frame for angle estimation.
• To compare the new technique against freehand PS placement.

Main Methods:

• Ex vivo porcine lumbar spine samples were used.
• The perpendicular probing and screwing technique (PPST) involved orienting the pedicle perpendicular to the ground.
• PS placement was compared between PPST and a freehand control group.
• Computed tomography was used to analyze rotational offsets and pedicle wall penetration.

Main Results:

• PPST significantly reduced medial rotational offsets (2.89° ± 0.31° vs 5.83° ± 0.57°).
• PPST also reduced rostrocaudal rotational offsets (2.92° ± 0.45° vs 4.81° ± 0.65°).
• Mean pedicle wall penetration was significantly lower with PPST (0.28 ± 0.12 mm vs 0.80 ± 0.17 mm).

Conclusions:

• The PPST technique enhances pedicle screw positioning accuracy.
• This method leads to reduced pedicle wall penetration and increased surgical safety.
• PPST offers a simple, cost-effective alternative for institutions lacking computer-assisted surgical systems.