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Updated: May 5, 2026
An Anesthesia, Surgery, and Harvest Method for the Evaluation of Transpedicular Screws Using an In Vivo Porcine Lumbar Spine Model
Published on: May 31, 2017
In vivo analysis of insertional torque during pedicle screwing using cortical bone trajectory technique
Keitaro Matsukawa1, Yoshiyuki Yato, Takashi Kato
1*Department of Orthopaedic Surgery, National Defense Medical College, Tokorozawa, Saitama, Japan; and †Department of Orthopaedic Surgery, National Hospital Organization, Murayama Medical Center, Tokyo, Japan.
The cortical bone trajectory (CBT) technique for pedicle screws significantly increases insertional torque compared to traditional methods. This in vivo study demonstrates CBT screws achieve approximately 1.7 times higher torque, enhancing spinal fixation stability.
Area of Science:
- Spine surgery
- Orthopedic biomechanics
- Surgical instrumentation
Background:
- The cortical bone trajectory (CBT) technique maximizes engagement with cortical bone.
- Previous cadaveric studies suggested CBT's biomechanical advantages.
- No in vivo studies had evaluated the mechanical behavior of the CBT technique.
Purpose of the Study:
- To investigate the effectiveness of the CBT technique in spinal fusion.
- To measure and compare the insertional torque of CBT screws versus traditional pedicle screws in vivo.
Main Methods:
- Intraoperative measurement of insertional torque for CBT and traditional pedicle screws in 48 patients.
- Comparison of 162 CBT screws and 36 traditional screws.
- Correlation analysis between insertional torque and bone mineral density.
Main Results:
- CBT screws exhibited significantly higher mean maximum insertional torque (2.49 ± 0.99 Nm) compared to traditional screws (1.24 ± 0.54 Nm).
- CBT screws demonstrated 2.01 times higher torque overall and 1.71 times higher torque in a direct side-by-side comparison.
- Positive linear correlations were found between insertional torque and bone mineral density for both techniques.
Conclusions:
- The CBT technique provides substantially higher insertional torque than the traditional method in vivo.
- This increased torque suggests potentially improved screw fixation and stability with the CBT technique.
- Further research can explore the long-term clinical outcomes associated with CBT screw placement.
