Feasibility and accuracy evaluation of novel 2D instant navigation system on spinal surgery - a preclinical study.

Background: Intraoperative navigation has significantly facilitated spinal surgery and enhanced surgical accuracy. Nevertheless, it is often encumbered by the need for expensive equipment, a complex workflow, and frequently exhibits inefficiencies. Leveraging permanent calibration technology, we have developed a novel two-dimensional fluoroscopic image navigation system with the aim of streamlining and expediting the navigation process. In this study, we comprehensively evaluated its feasibility and accuracy.

Methods: The accuracy of the 2D-navigation system was rigorously assessed using a standardized high-precision mold. To validate the feasibility and accuracy of the novel navigation system for spinal surgery, the bare-bones of the pig lumbar spine are employed for evaluation. Subsequently, 2D navigation-assisted pedicle penetrations were meticulously carried out on the spine (L1-L5) of live animals. The navigation accuracy was quantified by comparing the visualized position of the surgical tool in the actual fluoroscopic image with the virtual position pre-planned by the navigation system.

Results: During the experimental process, an excellent correlation between the virtual fluoroscopic images and actual fluoroscopic images was prominently observed. The navigation positioning accuracy, as evaluated by the standardized high-precision mold, was determined to be 0.54±0.16mm (AP view) and 0.57±0.14mm (lateral view). Specifically, in the bare-bones of the pig lumbar spine, the average distance errors between the virtual and actual fluoroscopic images under anteroposterior and lateral views were 0.99±0.48mm and 0.87±0.60mm, respectively. Meanwhile, the average angle errors were 0.41±0.29 $_{}^{\circ }$ and 0.37±0.11 $_{}^{\circ }$ , respectively. In the surgical procedure on normal adult pigs (L1-L5), the average distance errors were 1.14±0.58mm(95% CI [0.50-0.59]) and 1.54±0.79mm(95% CI [0.11-0.12]), respectively. The corresponding average angle errors were 0.61±0.49 $_{}^{\circ }$ (95% CI [0.33-0.35]) and 0.40±0.31 $_{}^{\circ }$ (95% CI [0.33-0.47]), respectively. Throughout a single navigation registration and the entire surgical procedure, the navigation accuracy across the L1 to L5 segments remained consistently high, with no statistically significant differences detected among the segments (p>0.05).

Conclusion: The two-dimensional fluoroscopic image navigation system based on permanent calibration technology is characterized by a rapid and convenient workflow. It demonstrates high-level navigation accuracy, thereby meeting the stringent requirements for spinal navigation in live surgical procedures.