Risk Factors of Unsatisfactory Robot-Assisted Pedicle Screw Placement: A Case-Control Study

Abstract

Objective To identify potential risk factors of unsatisfactory screw position during robot-assisted pedicle screw fixation. Methods A retrospective analysis of robot-assisted pedicle screw fixation performed in Beijing Jishuitan Hospital from March 2018 to March 2019 was conducted. Research data was collected from the medical record and imaging systems. Univariate tests were performed on the potential risk factors (patient’s characteristics and surgical factors) of unsatisfactory screw position during robot-assisted pedicle screw fixation. For statistically significant variables in univariate tests, a logistic regression test was used to identify independent risk factors for unsatisfactory screw position. Results A total of 780 pedicle screws placed in 163 robot-assisted surgeries were analyzed. The rate of perfect screw positions was 93.08%, and the unsatisfactory rate was 6.92%. In patients with severe obesity (body mass index ≥ 30 kg/m2) (odds ratio [OR], 2.459; 95% confidence interval [CI], 1.199–5.044; p=0.014), osteoporosis (T ≤ -2.5) (OR, 1.857; 95% CI, 1.046–3.295; p=0.034), and the segments 3 levels away from the tracker (OR, 2.216; 95% CI, 1.119–4.387; p=0.022), robot-assisted pedicle screw placement has a higher risk of screw malposition. Conclusion During robot-assisted pedicle screw placement for patients with severe obesity, osteoporosis, and segments 3 levels away from the tracker, vigilance should be maintained during surgery to avoid postoperative complications due to unsatisfactory screw position.

Keywords

• robot-assisted surgery
• pedicle screw
• accuracy
• risk factor