Technique for Validation of Intraoperative Navigation in Minimally Invasive Spine Surgery.

Background: Intraoperative 3-dimensional navigation is an enabling technology that has quickly become a commonplace in minimally invasive spine surgery (MISS). It provides a useful adjunct for percutaneous pedicle screw fixation. Although navigation is associated with many benefits, including improvement in overall screw accuracy, navigation errors can lead to misplaced instrumentation and potential complications or revision surgery. It is difficult to confirm navigation accuracy without a distant reference point.

Objective: To describe a simple technique for validating navigation accuracy in the operating room during MISS.

Methods: The operating room is set up in a standard fashion for MISS with intraoperative cross-sectional imaging available. A 16-gauge needle is placed within the bone of the spinous process before intraoperative cross-sectional imaging. The entry level is chosen such that the space between the reference array and the needle encompasses the surgical construct. Before placing each pedicle screw, accuracy is verified by placing the navigation probe over the needle.

Results: This technique has identified navigation inaccuracy and led to repeat cross-sectional imaging. No screws have been misplaced in the senior author's cases since adopting this technique, and there have been no complications attributable to the technique.

Conclusion: Navigation inaccuracy is an inherent risk in MISS, but the described technique may mitigate this risk by providing a stable reference point.