Robotic Assisted Percutaneous Lumbopelvic Fixation

Background: High energy pelvic trauma is often associated with mechanically unstable sacral fractures especially with vertical shear. Lumbopelvic Fixation (LBF) is a fixation construct designed to oppose shear. However, open surgery is associated with significant rates of wound complications, infection, and prominent hardware. Our hypothesis was that utilizing advanced 3D imaging (3DCT) plus robotic guidance will enable to utilize minimally invasive techniques. The aim of the study was to describe the technique of robotic assisted percutaneous LBF.

Methods: Four patients were operated using this technique between 2014–2017. Patients were positioned prone on a radiolucent table. Robotic placement of L4, L5 and iliac pedicle screws was planned on previously obtained CT and intraoperative registration was done using CT-fluoro merge algorithm. In displaced fractures manipulation of the broken hemipelvis was done and provisionally fixed with pins. A 3D intraoperative scan (Arteis Zeego, Siemens, Germany) was obtained and used as a new dataset for planning the trajectory of the implants. A miniature motorized Robot (Renaissance, Mazor, Caesaria Israel) was placed on a dynamic reference bridge (DRB) for the insertion of the screws as planned. Percuatneous placement of connecting rods was done and a verification 3D scan was performed.

Results: Mean patient age was 32.7. Mechanisms of injury were motor vehicle accidents and falls. Average operative time was 338.2 min. All fracture healed between 6-12 weeks postoperatively. No wound complications were observed. All patients were operated using neuromonitoring that was unchanged during the procedures. No residual neurological deficit was noted in intraoperative 3DCT demonstrated no breaching of neural structures in any of the screws.

Conclusion: The preliminary results of Robotic Assisted Percutaneous LPF for unstable sacral fractures is promising, reducing radiation exposure and potentially reducing the complication rate.