Currently Adopted Criteria for Pedicle Screw Diameter Selection

Area of Science:

• Spine surgery
• Orthopedic surgery
• Biomechanical engineering

Background:

• Transpedicular screw insertion is common for spinal correction but less utilized in the thoracic spine due to technical challenges and risks.
• Narrower thoracic pedicles increase the difficulty and risk of pedicle wall breach during screw insertion.
• Optimal screw selection balances fixation strength with vertebral pedicle integrity.

Purpose of the Study:

• To systematically review criteria for thoracic pedicle screw diameter selection.
• To guide surgeons on the impact of screw diameter on pedicle breaching and fixation strength.
• To address the challenges of thoracic pedicle screw placement.

Main Methods:

• Systematic literature review.
• Focused on studies reporting screw diameter selection, pedicle dimensions, fixation strength, and breach rates.

Main Results:

• Twenty-nine articles were included in the review.
• Data on fixation strength, breach rate, and screw diameter relative to pedicle width were analyzed.
• No universally accepted criteria for thoracic pedicle screw diameter selection were found.

Conclusions:

• Screw diameters around 80% of pedicle width are often used but rarely reported for the midthoracic spine.
• Smaller thoracic pedicles and inadequate hardware lead to higher breach rates.
• Specific screw diameter selection by vertebral level is needed to maximize cortical bone purchase and minimize breach risk.