• Masahiko Takahata, Katsuhisa Yamada, Iwata Akira, Tsutomu Endo, Hideki Sudo, Hidetoki Yokoyama, and Norimasa Iwasaki.
• Department of Orthopedic Surgery, Hokkaido University Graduate School of Medicine, Kita-15 Nishi-7, Kita-ku, Sapporo, 060-8638, Japan. takamasa@med.hokudai.ac.jp.
• Eur Spine J. 2018 Nov 1; 27 (11): 2754-2762.

PurposeThe cervical pedicle screw (CPS) requires careful and accurate placement because of the critical risk for neurovascular injury. This study aimed to introduce and evaluate the safety and efficacy of a new CPS placement technique using intraoperative C-arm cone-beam CT (CBCT) and a pilot screw without navigation system.MethodsThis was a case-control study to compare the accuracy and safety of intraoperative C-arm CBCT-guided CPS placement with freehand CPS placement under lateral fluoroscopy using control data from a previous multicenter study. A total of 166 CPSs were inserted under intraoperative C-arm CBCT guidance in 48 consecutive patients (20 rheumatoid arthritis, 16 degenerative spinal disorders, 6 spinal tumor, 2 congenital deformity, 2 ossification of posterior longitudinal ligament, and 2 fracture dislocation). Accuracy and safety of CPS placement were assessed.ResultsThe overall malposition rate was 2.4% (4 screws in grade 1: malposition by less than half-screw diameter, 0 in grade 2: malposition by more than half-screw diameter), which was significantly lower than the reported malposition rate of 14.8% in lateral fluoroscopy-guided freehand placement. There were no complications directly related to CPS insertion. The average estimated effective radiation dose per surgery was 14.7 mSv.ConclusionsThe novel technique enables intraoperative adjustment of the trajectory of the CPS as well as confirmation of the CPS path before penetrating the isthmus of the pedicle, resulting in accurate and safe CPS placement, which outweighs the demerits of radiation exposure. These slides can be retrieved under Electronic Supplementary Material.

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