Placement of LC-II and trans-sacral screws using a robotic arm in a simulated bone model in the supine position – a feasibility study

PURPOSE: The use of a robotic arm has been well-described in the literature for the placement of pedicle screws in spine surgery as well as implants for sacroiliac joint fusion. There are no reports describing the use of a robotic arm to place screws in osseous fixation pathways (OFPs) employed in the treatment of pelvic ring and acetabular fractures outside of a single center in China. Using a Sawbones model, the authors describe a technique for using a robotic arm widely available in Europe and the Americas for placement of 6.5 mm cannulated screws into two OFPs commonly used in the treatment of pelvic and acetabular fractures. METHODS: Using the Mazor X Stealth Edition (MSXE) robot from Medtronic, the authors were able to place a pin into the pelvis onto which the robot was docked. The authors were then able to designate the area of interest using navigated instruments, and in combination with the MSXE “scan and plan” marker, obtain cross-sectional imaging using the O-Arm and successfully register the MSXE robot. We then used the provided software to plan trajectories for the lateral compression type 2 (LC-II) screw pathway as well as a pathway for a trans-ilio-trans-sacral screw. We describe in detail the steps for setup, planning and placement of 6.5 mm cannulated screws using the MSXE robotic arm into these two OFPs. RESULTS: Visual inspection and plain x-rays demonstrated successful placement of the screws into the two planned OFPs. No breach of cortical bone was seen on either visual inspection of the model or demonstrated on post-procedure x-rays. CONCLUSION: It is possible to use the Mazor X Stealth Edition robot to place screws into the LC-II and trans-ilio-transsacral screw pathways in a Sawbones model. This is only a feasibility study, and should in no way be taken to suggest that clinical application of this technique should be attempted.