Accuracy of Navigated High-Speed Drill-Assisted Cervical and Upper Thoracic Pedicle Screw Placement-A Single Center Experience with 1112 Pedicle Screws

Abstract

Background/Objectives: While biomechanically superior, cervical pedicle screw placement is technically challenging, and therefore typically performed only in centers with the aid of navigation. The purpose of this study was to analyze the accuracy and safety of navigated cervical pedicle screw (CPS) placement using intraoperative imaging with a workflow using a navigated high-speed drill in a large single-center cohort. Methods: We conducted a retrospective analysis of 205 patients undergoing posterior cervical or cervicothoracic instrumentation between January 2018 and June 2024. Accuracy was assessed using the Gertzbein-Robbins classification, with grades 0 and 1 considered satisfactory. Surgical workflow, intraoperative imaging, and complications were analyzed. Results: A total of 1112 pedicle screws, including 888 cervical and 224 upper thoracic screws, were evaluated. 801 were grade 0 (72.0%), 250 grade 1 (22.5%), 56 grade 2 (5.0%), and 5 grade 3 (0.4%). Cervical screws achieved satisfactory placement grades 0 and 1 in 93.1%, and upper thoracic screws in 100% (92.0% grade 0, 8.0% grade 1). Grade 3 breaches occurred in C2, C3, C5, C6, and C7, with one case each. There were no cases of implant-related neurovascular injuries. Conclusions: This study demonstrates high screw accuracy with a low observed complication rate. No revision surgeries were required due to screw malposition, but 7 cases of screw loosening occurred. However, the retrospective design and reliance on intraoperative imaging limit the generalizability of the findings.

Keywords: Gertzbein–Robbins classification; O-arm navigation; cervical pedicle screws; cervical spine; navigated high-speed drill; navigation; screw accuracy; workflow.

Figure 1

Typical setup in the operating room. The intraoperative imaging system (O-Arm) is sterile draped and in the parking position, placed caudally. The screen of the navigation unit is placed contralateral to the surgeon. The scrub nurse, instruments, and implant trays are located cranially.

Figure 2

Screenshot of the navigation screen, showing the drilling for a C6 pedicle screw on the left side using a navigated high-speed drill. The trajectory is visualized in axial and sagittal views, as well as in the Probe’s Eye view. In this specific case, a junctional fracture at C6/7 occurred following an anterior fusion from C4 to C6, necessitating posterior fusion. A = anterior, R = right, P = posterior, S = superior, I = inferior.

Figure 3

Postoperative X-ray after implantation of pedicle screws from C3-T1. In this specific case, spondylitis several years after anterior cervical discectomy and fusion with implant loosening of the upper cage at C4/5 made revision surgery necessary with implantation of a new cage at C4/5, and subsequent posterior instrumentation. R = right.

Figure 4

Stacked bar chart of the frequencies of the Gertzbein–Robbins-grades per vertebral level.

Figure 5

Examples of the different Gertzbein–Robbins grades on intraoperative, axial O-arm images. (a) shows grade 0 (no cortical breach), (b) grade 1 (breach < 2 mm), (c) grade 2 (breach 2–4 mm), and (d) grade 3 (breach > 4 mm).