The Cortical Bone Trajectory Screw Technique Assisted by the Mazor Renaissance Robotic System as a Salvage Strategy for Failed Lumbar Spine Surgery: Technical Note and Case Series

Abstract

Purpose

The objective of this study was to describe the Mazor Renaissance robotic system-assisted CBT (cortical bone trajectory) screw technique as a salvage strategy for failed lumbar spine surgery.

Patients and Methods

Between January 2018 and June 2022, 7 patients underwent salvage surgery with the CBT screw fixation technique assisted by the Mazor Renaissance robot system in our institution. Intraoperative observations were recorded for blood loss, duration of operation, and fluoroscopy time. Complications related to CBT screws were also recorded. The accuracy of CBT screws was recorded in accordance with the modified Gertzbein-Robbins classification. The JOA (Japanese Orthopedic Association) score for low back pain was used to evaluate surgical outcomes.

Results

A total of 26 CBT screws were placed in 7 patients, including 4 females and 3 males. Three patients underwent ASD (adjacent segment disease) and four patients underwent lumbar union failure with loose or compromised PSs (pedicle screws). The mean operation time was 129.29 ± 32.97 minutes, the mean blood loss was 180 ± 52.60 mL, and the mean intraoperative fluoroscopy time was 14.29 ± 3.15 s. All screws were clinically acceptable according to the Gertzbein-Robbins classification. There were no complications related to CBT screws in any of the cases. The JOA scores for low back pain of all patients were significantly improved at the final follow-up.

Conclusion

The CBT screw fixation technique supplemented the traditional PS fixation technique, which can be performed as a salvage strategy for failed lumbar spine surgery and achieved good clinical results. The spinal robot was very helpful in evaluating pedicle size and determining CBT screw direction, especially in a previously instrumented lumbar pedicle.

Keywords:

• CBT screw
• robot-assisted
• salvage strategy
• ASD

Ethical Approval

The study was approved by the ethical committee of the Affiliated Hospital of Qingdao University (approval number: QYFY WZLL 27404). All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. Pre-operative explanation of the procedure was made to all patients before obtaining informed consent. All patients mentioned in this article have read the manuscript, consented to publication and signed the patient consent form.

Disclosure

All authors declare that they have no conflicts of interest related to this work.

Additional information

Funding

This work was supported by National Natural Science Foundation of China (82100940) and Qingdao Postdoctoral Application Research Project (2019).