Size selection and placement of pedicle screws using robot-assisted versus fluoroscopy-guided techniques for thoracolumbar fractures: possible implications for the screw loosening rate

Abstract

Background There has been increased development of robotic technologies for the accuracy of percutaneous pedicle screw placement. However, it remains unclear whether the robot really optimize the selection of screw sizes and enhance screw stability. The purpose of this study is to compare the sizes (diameter and length), placement accuracy and the loosening rate of pedicle screws using robotic-assisted versus conventional fluoroscopy approaches for thoracolumbar fractures. Methods A retrospective cohort study was conducted to evaluate 70 consecutive patients [34 cases of robot-assisted percutaneous pedicle screw fixation (RAF) and 36 of conventional fluoroscopy-guided percutaneous pedicle screw fixation (FGF)]. Demographics, clinical characteristics, and radiological features were recorded. Pedicle screw length, diameter, and pedicle screw placement accuracy were assessed. The patients’ sagittal kyphosis Cobb angles (KCA), anterior vertebral height ratios (VHA), and screw loosening rate were evaluated by radiographic data 1 year after surgery. Results There was no significant difference in the mean computed tomography (CT) Hounsfield unit (HU) values, operation duration, or length of hospital stay between the groups. Compared with the FGF group, the RAF group had a lower fluoroscopy frequency [14 (12–18) vs. 21 (16–25), P < 0.001] and a higher “grade A + B” pedicle screw placement rate (96.5% vs. 89.4%, P < 0.05). The mean screw diameter was 6.04 ± 0.55 mm in the RAF group and 5.78 ± 0.50 mm in the FGF group (P < 0.001). The mean screw length was 50.45 ± 4.37 mm in the RAF group and 48.63 ± 3.86 mm in the FGF group (P < 0.001). The correction loss of the KCA and VHR of the RAF group was less than that of the FGT group at the 1-year follow-up [(3.8 ± 1.8° vs. 4.9 ± 4.2°) and (5.5 ± 4.9% vs. 6.4 ± 5.7%)], and screw loosening occurred in 2 out of 34 patients (5.9%) in the RAF group, and 6 out of 36 patients (16.7%) in the FGF group, but there were no significant differences (P > 0.05). Conclusion Compared with the fluoroscopy-guided technique, robotic-assisted spine surgery decreased radiation exposure and optimizes screw trajectories and dimensions intraoperatively. Although not statistically significant, the loosening rate of the RAF group was lower that of than the FGT group.

Surgical outcomes of robotic-assisted percutaneous fixation for thoracolumbar fractures in patients with ankylosing spondylitis

“…In our study, the use of robot-assisted screw placement eliminates the need for repeated uoroscopy during surgery, thereby signi cantly reducing radiation exposure. This nding has also been observed in other studies [13,15,37]. In the future, we will continue to closely monitor intraoperative radiation exposure, further present radiation-related data, and conduct controlled studies.…”

“…However, in patients with AS, the signi cant alterations in bony structure and anatomy result in a lack of identi able landmarks, which increases the di culty of pedicle screw implantation and imposes demanding technical requirements on the operator [9]. Therefore, robot-assisted surgical xation for AS combined with thoracolumbar fractures has become possible, because it has been con rmed to have the advantages of minimizing radiation exposure and improving the accuracy of screw placement in the treatment of common spinal fractures [13][14][15]. In addition, by utilizing robotic assistance, surgeons have the exibility to select screws with a larger diameter and increased length [16].…”

Comparison of 3D-navigation and fluoroscopic guidance in percutaneous pedicle screw placement for traumatic fractures of the thoracolumbar junction

“…It has been shown that navigation allows an increase of screw diameter/pedicle width ratio for thoracolumbar pedicle screw placement ( Mandelka et al, 2023 ). Du et al found an improved accuracy, increased screw diameters and a lower loosening rate in robotic-assisted navigated pedicle screw placement ( Du et al, 2022 ). The results regarding screw diameter/pedicle width ratio in the current study are in accordance with these findings.…”

Spine Surgical Robotics: Current Status and Recent Clinical Applications

“…90,91 In addition, the robot assistance allows for the placement of "optimal screws" with longer length and larger diameter to maximize structural stability and reduce screw loosening, thus creating conditions for successful fusion. 44,92 (4) RA spine surgery is more minimally invasive: RA spine surgery is associated with smaller surgical incision, less vascular and nerve damage due to improved visualization of the surgical field intraoperatively, faster postoperative recovery, shorter hospital stay, lower complication rates. 29 A multicenter study led by Lee et al 93 explored the 5-year trends in outcomes and complications in 722 patients undergoing RA spine surgery using Mazor robot, and found that the rates of postoperative complication such as nerve injury and loss of motor/sensory function remains extremely low over time (1.7%-5.7%), and the length of hospital stay can be reduced by almost 1 day, as the surgeon's experience with robots increased.…”

“…At the same time, the high stability of the robotic platforms could obviously reduce deviation of screw placement performed by less experienced young surgeons, and shorten the screw placement time, this may also be related to the fact that young surgeons can adapt quickly to new techniques [ 90 , 91 ]. In addition, the robot assistance allows for the placement of “optimal screws” with longer length and larger diameter to maximize structural stability and reduce screw loosening, thus creating conditions for successful fusion [ 44 , 92 ].…”