Robot-assisted three column trans-intervertebral osteotomy by combined navigated trajectories: A feasibility study and technical report.

Introduction: Spinal osteotomy is indicated for malalignment and deformity, but the degree of osseous resection is mainly determined by the surgeon's experience. Navigation and robotics are techniques for the precise placement of pedicle screws. Research question: Can an innovative combined navigated trajectory (CNT) design based on a spinal robot achieve precise 3-column osteotomy. Materials and methods: The Mazor X Stealth Edition (MXSE) robotic system was used to design and execute type II trans-intervertebral osteotomy (TIO) via CNT. Preoperative CT images of a synthetic spine model and a cadaveric specimen were processed to create multitrajectory plans aligned in the sagittal plane, traversing the pedicle bases. The intraoperative workflow included a robotic setup, bone mount bridge fixation, pre- and postresection registration, and robotic trajectory drilling followed by osteotomy completion via a bone chisel. Results: After posterior element resection, the osteotomy vertebrae were successfully registered in both the synthetic and cadaveric models. Multitrajectory drilling followed by chisel combination achieved complete TIO. Quantitative analysis revealed that the deviation of the posterior vertebral wall from the preoperative plan was less than 2 mm in both specimens, with corresponding length and angle differences of -4.00 %/-1.55° (synthetic) and -6.95 %/-2.59° (cadaveric). Discussion and conclusion: Combined navigated trajectory spinal resection is a possible technique for quantitative spinal osteotomy using MXSE. Biomechanical and clinical studies are needed to further evaluate the suitability and safety of this technique.