Introduction: Minimally-invasive (MIS) approaches to the anterior column such as lateral (LLIF) frequently require percutaneous screw fixation to achieve circumferential instrumentation. Robotic guidance represents a new technology for augmenting the surgical workflow to improve screw placement accuracy and decreasing the ionizing radiation exposure to the surgical team. Here we report our initial experience with robotically assisted percutaneous screw placement and review our surgical workflow.
Methods: Consecutive patients undergoing single level LLIF with robotically assisted percutaneous pedicle screw fixation (PSF) in prone or lateral decubitus position (Fig 1) were identified. A novel CT-guided robotic guidance arm was used for screw placement (ExcelsiusGPS) in combination with the O-Arm (Medtronic). Demographic data, surgical timing, and perioperative complications were collected. Screw accuracy was determined with routine post-operative CT; breach was defined as violation of lateral or medial pedicle wall.
Results: We identified 11 patients who underwent robotically assisted PSF; robotic placement of screws was aborted in one surgery due to challenging anatomy. Mean age was 63.1±12.5, 50% were female, with mean BMI 31.4±5.5. Most common pathology was L4-5 spondylolisthesis (8/10, 80%). Mean surgical time for PSF was 183±51 minutes, with a decrease over six months (r=-0.49, p=0.15). A total of 40 screws were successfully placed (40/44, 90.1%), primarily in the prone position (9/10, 90%). One pedicle breach was observed on postoperative CT (1/40, 2.5%), with no associated CSF leak or neurological deficit. Mean length of stay following surgery was 51.1±34.2 hours. Two complications occurred (2/10, 20%) in the perioperative period.
Conclusions: Robotic guidance provides for accurate percutaneous PSF in the majority of cases. Nonetheless, the technology still represents an early phase of development, with a steep learning curve that trends towards improved surgical times with subsequent use. Future studies are needed to demonstrate the utility of this novel guidance system and continued improvement in workflow.
Patient Care: Robotically assisted screw placement represents an exciting new direction for spinal surgery. By augmenting implant placement and facilitating standardization in spinal surgery this technology my lead to improved accuracy, reduced variability in screw trajectory, and ultimately translate to improved surgical outcomes. This exploratory study describes our experience with the technology and provides framework for improvement.
Learning Objectives: By the conclusion of this session, participants should be able to: 1) identify the two different positioning options for robotically assisted percutaneous screw placement; 2) describe the surgical workflow of a robotic system; 3) list the limitations of robotic screw placement and key aspects of surgical anatomy that dictate feasibility
References: T. Fujishiro et al., Accuracy of Pedicle Screw Placement with Robotic Guidance System: A Cadaveric Study. Spine 40, 1882 (Dec, 2015).
2. P. A. Laudato, K. Pierzchala, C. Schizas, Pedicle Screw Insertion Accuracy Using O-Arm, Robotic Guidance, or Freehand Technique: A Comparative Study. Spine 43, E373 (Mar 15, 2018).
3. S. C. Overley, S. K. Cho, A. I. Mehta, P. M. Arnold, Navigation and Robotics in Spinal Surgery: Where Are We Now? Neurosurgery 80, S86 (Mar 1, 2017).
4. T. M. Urakov, K. H. Chang, S. S. Burks, M. Y. Wang, Initial academic experience and learning curve with robotic spine instrumentation. Neurosurgical focus 42, E4 (May, 2017).
5. I. H. Lieberman, M. A. Hardenbrook, J. C. Wang, R. D. Guyer, Assessment of pedicle screw placement accuracy, procedure time, and radiation exposure using a miniature robotic guidance system. Journal of spinal disorders & techniques 25, 241 (Jul, 2012).
6. N. Keric et al., Evaluation of robot-guided minimally invasive implantation of 2067 pedicle screws. Neurosurgical focus 42, E11 (May, 2017).