Chetan K. Patel, MD, moderated a symposium about robotics and navigation in the spine surgeon's operating room at the North American Spine Society Annual Meeting.
Defining its use
Srinivas K. Prasad, MD, gave a presentation titled "Critical Analysis of the Latest Robotic Technologies in Spine Surgery." He discussed the history of robotics in surgery and gave an overview of the various robotics paradigms and innovation.
"Going into it, we have to ask ourselves — like all technologies — what are the real questions? What are we trying to solve here?" he said. "We have to ask ourselves what would robotic technology be useful for in spine surgery. Those [questions] have to guide us, in a sense, to what procedures would be done better or more efficiently in spine surgery."
He discussed the potential benefits of using robotic technology or navigation, including improved pedicle screw placement, reduced placement time, less invasive procedures which lead to less pain and blood loss, as well as reduced fluoroscopy use. However, more questions remain to better define the objectives of the robotic technology.
"Are we looking at specific maneuvers like arthrodesis? Are we looking at putting screws down? Is it looking at just doing a better job at decompression? Are we going to be developing robots that allow us to do a better job at these maneuvers? Are we going to see deformity robots, tumor robots; in other words, robots that are designed around a clinical domain within spine surgery or are we going to make them more procedure-based?" he said. "That is an important question to ask going into it."
Most of the innovation right now in robotics is on pedicle screw placement. "I think some of the reason for the resistance or biased against it is it's just allowing you to do something potentially better that you can already do readily," he said. "It's not leveling the playing field in any way."
He sees technologies moving more toward innovations that can build upon current technology to create better procedures and outcomes that level the playing field. Future technology may address cost reduction in spine surgery and generate better clinical results.
"We have to ask ourselves what role is it going to have in the next five years? Is it important to pick up this technology now as a building block to something greater later?" Dr. Prasad said.
Argument for robotics in spine surgery
Mark B. Dekutoski, MD, of The CORE Institute gave a presentation on why all spine surgeons should incorporate robotic technology into their operating rooms. The reasons he mentioned include:
• Pre-operative planning
• Ability to make a visual construct
• Advance your media presence
• Challenge your OR environment
• Fund research
"Spine surgery is a deliverable. We deliver an outcome and we deliver a process for a set disease; hopefully it’s indicated, but it’s not art guys, it’s a deliverable," said Dr. Dekutoski. "That said, skill matters a bit, process matters a lot and when you look at robots in the current environment with urology applications and GYN applications, you have a fit environment for feedback...That's of real surgical value."
Michael Mac Millan, MD, also spoke on why surgeons should implement robotic navigation into their practice.
"The field of medicine will deliver a more consistent product if we use navigation," he said. "As the field of spine surgery we should endorse it for that reason. But if you just think of the pedicle screw, you are losing the true value of navigation. Navigation goes way beyond just putting in the pedicle screw."
While Dr. Mac Millan is a general spine surgeon, the navigation has helped him feel more comfortable performing a variety of spinal procedures. "The majority of my practice is lateral base surgery and I think this really shows how navigation can expand our capabilities when you can not only do the things you do normally but you can actually do things you don't do normally and get better outcomes and better results," he said.
Argument against robotics in spine surgery
Dr. Prasan presented the case against robotic spine surgery as well. He cited the lack of strong evidence to support better clinical outcomes or cost-effectiveness. Many of the international studies cited on robotics image guidance for screw placement had small patient groups and didn't show significant difference in outcomes or radiation exposure.
"I think the fact that there is so little data makes it really hard to make a conclusive conclusion from it," he said. He sighted three papers on robotic-assisted spine surgery, including "Accuracy of Robot-Assisted Placement of Lumbar and Sacral Pedicle Screws," a prospective randomized comparison to conventional freehand screw implementation that was published in a 2012 issue of Spine. The study of 60 patients found intraoperative revision rate of 93 percent using fluoro-guided technique and 85 percent using robotic assistance.
The study also showed 11 minutes longer operating room time for robotic-assisted surgery and radiation dosage remained about the same.
"In aggregate, I think the evidence for this technology is really limited and I think there is a learning curve for this as well," said Dr. Prasan. "The accuracy doesn't appear to be statistically superior based on the data that's out there right now, at least in the populations that we've looked at. Radiation exposure doesn’t seem to be dramatically different statistically...There may be a role for robotic-assistance in screw placement but maybe in a narrow population."
Dr. Dekutoski also spoke on the con side, arguing that surgeons should only use robotics when it's the best way to navigate difficult anatomy.
"Navigation is just another tool in the difficult situations and you have to balance the risks and benefits of the patient," he said. "Perhaps sometimes that's a judgment where you send them to someone else with the resources and who has that experience. Pretty clearly there are folks that get better at things with more exposure."
Cost-effectiveness
Eric A. Potts, MD, discussed the cost-effectiveness of using robotics in spine surgery. There are no studies currently on the cost-effectiveness of robotic spine surgery, but there is data on image-guided spinal procedures. A study conducted by Robert Watkins IV, MD, Akash Gupta, MD, and Robert Watkins III, MD, showed image-guidance reduced revision rate from 3 percent to 0 percent and resulted in a cost savings of $71,286 to the institution in the first 100 cases, given the average cost of revision surgery was $23,762.
If these results are assumed, and you consider the cost of the Mazor system is around $789,000 including the robot, workstation, instrument tray and one year tech support with $1,200 worth of disposables per case, you would have to prevent 32 revision cases to realize cost-effectiveness.
Another opportunity to save money is reducing operating room time. Isador Lieberman, MD, led a study examining how long it took experienced and new surgeons with the robotic system and compared their time to surgeons who were not using robotic guidance. While the surgeons using the robotic system had shorter times, the gap wasn't large enough to make a significant difference with the fiscal analysis, said Dr. Potts.
"The Mazor system, the one that is really commercially available, is an expensive system," said Dr. Potts. "There is really no data considering cost effectiveness. For this to be cost effective, I will submit to you that you need to eliminate the revisions or make this faster and more reproducible. In the current state, I’m not sure we're there...I think it's in it's infancy and as time goes on we'll be able to come up with the answer is it cost effective but at this point we don't have enough data."
Eric W. Nottmeier, MD, spoke about cost-effectiveness of intraoperative imaging and navigation in spine surgery. Physicians that want their hospital to purchase the equipment may not succeed with the lower radiation argument because administrators are focused on decreasing costs. However, focusing on marketing potential, fewer complications or reduced operating room time could make a difference.
"From an OR standpoint, OR time is money," he said. According to the statistics he presented, a simple cases cost $29 per minute and complex cases are around $80 per minute in the OR, with an average cost of $65 per minute. "If you can cut 30 minute off your OR time you can save $2,000 for the hospital per case just right there."
He also mentioned the cost-benefit of using technology that allows surgeons to perform procedures with non-cannulated pedicle screws as opposed to cannulated pedicle screws. Cannulated pedicle screws cost on average $250 more than non-cannulated pedicle screws, according to the report, and minimally invasive single-level fusions could save $1,000 with non-cannulated screws. Two-level fusions could save $1,500 and three-level fusion have a $2,000 cost savings potential.
"In conclusion, navigation and cbCT platforms are significant capital expenses for hospitals," he said. "Decrease in OR time, revision surgery for misplaced instrumentation and instrumentation expenses can be realized with the implementation of this technology. This in turn results in significant cost savings to the hospitals that can exceed the original cost of this technology within the first two years of its implementation."
Future of robotics and navigation
Dr. Patel returned to speak on where robotics is headed in spine surgery. Future sustainable technologies must deliver reproducible results, improved accuracy and ease of planning and execution, he said. Ideally, robotic technology would promote consistent screw placement among surgeons.
"When you look at the orthopedic arena and see what is happening with robotic burs and combination of navigation robotic burs, I think there is some opportunity there to help us with doing that because the bulking of the bony structures perhaps even as things get better in the refinement," he said. "As we get into procedures that are smaller and smaller, we are going to need better visualization. Or we are going to need a substitute for visualization such as a hybrid MR/CT picture to really see where we are at."
However, before moving into the future, Dr. Patel said technology will address the reservations surgeons have with incorporating the systems today, including accuracy and improved outcomes to standard care. The cost-benefit ratio must also make sense for the patient.
"The bottom line is I think with the refinement we have today and the technology we have in the works right now, we can get to the point where we can deliver reproducible outcomes that are superior to what we do today," he said. "However, we need to prove that. We need the comparative literature to show we can actually deliver on the promise. I think having a procedural solution will allow us a wider option in technology so we will all be using it hopefully in our operating rooms."
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