A novel system for accurate lumbar spine pedicle screw placement based on three-dimensional computed tomography reconstruction

Baozhi Ding; Tangjun Zhou; Jie Zhao

doi:10.1016/j.jot.2020.03.010

A novel system for accurate lumbar spine pedicle screw placement based on three-dimensional computed tomography reconstruction

J Orthop Translat. 2020 Apr 19:23:101-106. doi: 10.1016/j.jot.2020.03.010. eCollection 2020 Jul.

Authors

Baozhi Ding¹, Tangjun Zhou¹, Jie Zhao¹

Affiliation

¹ Shanghai Key Laboratory of Orthopedic Implants, Department of Orthopedics, Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, 639 Zhizaoju Road, Shanghai, 200011, PR China.

Abstract

Objectives: The accuracy of pedicle screw placement strongly affects the outcome of spinal surgery and has mainly relied on the surgeons' experience. There is no simple, low-cost, and effective pedicle screw placement system to assist new spinal surgeons with less experience.

Methods: We designed a localization system with six parameters (starting point height [SP-H], starting point length [SP-L], transverse section angle, sagittal section angle [SSA], pedicle width [W] and height [H]) based on preoperative computed tomography reconstruction and combined it with the Roussouly classification to guide lumbar spine pedicle screw placement and analysed the change patterns of the six parameters in 50 participants.

Results: Based on the system, we confirmed that combining SP-H and SP-L can localize the entrance of the pedicle screw. Furthermore, we considered that SP-L and transverse section angle would be a new standard for determination of the transverse orientation of the pedicle screw. More importantly, the linear regression equations between H and W and SP-H and H were concealed. In addition, H and W can guide the appropriate selection of pedicle screw. Moreover, change patterns of SSA combined with the Roussouly classification indicate that SSA of L3 can be used as a benchmark to guide the establishment of sagittal alignment of the lumbar spine.

Conclusions: Understanding and applying the six-parameter localization system are essential for achieving accuracy in lumbar spine pedicle screw placement, and the system is a useful guide in the establishment of sagittal alignment.

The translational potential of this article: This study provides a new pedicle-screw placement system for accurate lumbar spine pedicle screw placement based on three-dimensional CT reconstruction, requiring six parameters to guide the system.

Keywords: CT scan; Pedicle screw; Placement; Roussouly classification; Starting point.