Cervical pedicle screw placement: feasibility and accuracy of two new insertion techniques based on morphometric data

Area of Science:

• Orthopedics
• Neurosurgery
• Anatomy

Background:

• Transpedicular fixation is crucial for subaxial cervical spine stabilization.
• Accurate cervical pedicle screw (CPS) placement relies on detailed pedicle anatomy knowledge.
• Developing precise surgical techniques is essential for effective spinal fixation.

Purpose of the Study:

• To assess subaxial cervical pedicle dimensions and axes.
• To compare the accuracy of two distinct CPS placement techniques using novel aiming devices.
• To evaluate the feasibility and precision of transpedicular fixation in the subaxial cervical spine.

Main Methods:

• Morphometric analysis of 60 subaxial cervical pedicles (C3-C7) from human cadavers using multislice CT.
• Comparison of two surgical techniques (ST1 and ST2) with different aiming devices for screw hole preparation.
• Postoperative assessment of 56 inserted carbon fiber polyetheretherketone (CF-PEEK) screws using CT imaging, categorized by placement accuracy (Grades I-III).

Main Results:

• No significant difference in overall accuracy between ST1 and ST2.
• ST2 showed a trend towards fewer Grade III misplacements (15% vs. 23% in ST1) and more Grade IIa placements (62% vs. 43% in ST1).
• Vertebral levels C4 and C5 were identified as most critical for screw malposition.

Conclusions:

• Preoperative CT evaluation with multiplanar reconstructions is essential due to cervical pedicle anatomical variability.
• Cadaver studies are vital for refining safer and less demanding transpedicular screw fixation procedures.
• Further research is planned to enhance the safety and clinical applicability of CPS fixation techniques.