What’s the Claim?
This systematic review and meta-analysis of 14 randomized trials found technology-assisted (robotic or computer-navigated) placement of pedicle screws in the thoracolumbar spine was more accurate than freehand (fluoroscopy-assisted) placement. Defining an accurate screw as a Gertzbein-Robbins grade A or B placement (fully intrapedicular position without cortical breech, or exceeding the pedicle cortex <2 mm), the odds ratio of an inaccurate screw placement was 2.66 (95% CI 1.24 to 5.72) when performed freehand compared to navigated or robotic. Differences in facet joint violation were even more dramatic — a relative risk >11 for screws placed freehand compared to tech-assisted. There were no differences in the risk of nerve injury or return to the operating room, but these events were uncommon.
How’s It Stack Up?
As a systematic review, it necessarily tracks closely with what’s been published, but it extends what we know in important ways. Pooling across studies here allows us to draw conclusions about screw accuracy from studies that disagreed with one another. In addition, the authors were able to show (with funnel plots) that the available evidence probably doesn’t suffer from positive-outcome bias, which gives us greater confidence in the main messages here. On the other hand, the authors claimed benefits to the new technology in terms of “major complications,” but we are not convinced of that, since they included endopints (like DVT and PE) that could not have been influenced by screw placement. Finally, the source studies were a bit of a mixed bag in terms of quality; only 5 of 14 received the top quality rating of “good’" (the quality scale rated studies as poor, fair, or good). This is no mere beauty contest — the kinds of bias that accumulate in poor- and fair-quality studies tend to make the new treatments look better than they really are.
What’s Our Take?
That last point is one to remember; this meta-analysis may paint a sympathetic picture about these new technologies. And interestingly, surgical time was not increased with navigated or robotic surgery, which suggests that the learning curve is not being measured here. Rather, these studies by and large were performed by people very comfortable with both approaches being compared. But even considering all that, we're bullish on these tools for pedicle screw placement. Unlike navigation and robotics in, say, joint replacement, the advantages shown in these spinal procedures, even discounted for the reasons noted above, are likely to be perceived by patients (stray pedicle screws can really sting). That’s important when deciding whether to try out these tools or to buy them for your center. The last word here goes to CORRelations’ advisor in Spine, and it is a word of caution: “These devices are not flawless. Image acquisition and implant placement can be subject to error. The surgeon is still doing the surgery, and you have to be able to recognize when things don’t look right or feel right and adjust accordingly. Unconditional trust in the technology will eventually get you in trouble.”
Matur AV, Palmisciano P, Duah HO, Chilakapati SS, Cheng JS, Adogwa O. Robotic and Navigated Pedicle Screws Are Safer and More Accurate Than Fluoroscopic Freehand Screws: A Systematic Review and Meta-analysis. Spine J. 2023;23:197-208.