Minimally invasive cervical spine stabilization: A multicenter study of completely percutaneous pedicle screw-rod instrumentation

Introduction: Minimally invasive posterior cervical fixation remains technically challenging due to narrow pedicle dimensions and proximity to neurovascular structures. This multicenter study evaluates the accuracy and safety of a dedicated minimally invasive cervical pedicle screw-rod system with 3D navigation guidance. Research question: Can minimally invasive cervical pedicle screw placement achieve accuracy rates comparable to open techniques while maintaining patient safety? Material and methods: Retrospective multicenter analysis of 46 patients (60.7 ± 17.4 years) undergoing percutaneous cervical pedicle screw-rod instrumentation at three German university centers (01/2022-04/2024). Indications included degenerative disease (n = 21), tumors (n = 13), trauma (n = 8), and inflammation (n = 4). Primary outcome was neurological status (Frankel classification); secondary outcomes included screw accuracy (Bredow classification), surgical characteristics, and complications. All procedures utilized 3D navigation based on cone-beam CT or intraoperative CT. Results: In total, 232 pedicle screws were implanted from C2 to T2. Favorable screw position (Bredow grades 1-2) was achieved in 89.7% overall, with significantly lower accuracy at C3-C6 versus other levels (86.0% vs. 95.4%, p = 0.0297). No permanent neurological deficits occurred. Two screws required intraoperative repositioning; zero revision surgeries were needed. Mean surgical duration was 148 ± 66min with blood loss of 236 ± 183 ml. Discussion and conclusion: Minimally invasive cervical pedicle screw-rod instrumentation with 3D navigation achieves high accuracy and safety comparable to open techniques. In the majority of cases, the technique supplemented anterior fusion for additional stability, but it may also serve as posterior-only instrumentation for in tumor-related osteolysis or traumatic injuries. Mid-cervical levels remain particularly challenging and require heightened vigilance.