Is Overlain Display a Right Choice for AR Navigation? A Qualitative Study of Head-Mounted Augmented Reality Surgical Navigation on Accuracy for Large-Scale Clinical Deployment

BACKGROUND

During the course of the past two decades, head-mounted augmented reality surgical navigation (HMARSN) systems have been increasingly employed in a variety of surgical specialties as a result of both advancements in augmented reality-related technologies and surgeons' desires to overcome some drawbacks inherent to conventional surgical navigation systems. In the present time, most experimental HMARSN systems adopt overlain display (OD) that overlay virtual models and planned routes of surgical tools on corresponding physical tissues, organs, lesions, and so forth, in a surgical field so as to provide surgeons with an intuitive and direct view to gain better hand-eye coordination as well as avoid attention shift and loss of sight (LOS), among other benefits during procedures. Yet, its system accuracy, which is the most crucial performance indicator of any surgical navigation system, is difficult to ascertain because it is highly subjective and user-dependent. Therefore, the aim of this study was to review presently available experimental OD HMARSN systems qualitatively, explore how their system accuracy is affected by overlain display, and find out if such systems are suited to large-scale clinical deployment.

METHOD

We searched PubMed and ScienceDirect with the following terms: head mounted augmented reality surgical navigation, and 445 records were returned in total. After screening and eligibility assessment, 60 papers were finally analyzed. Specifically, we focused on how their accuracies were defined and measured, as well as whether such accuracies are stable in clinical practice and competitive with corresponding commercially available systems.

RESULTS AND CONCLUSIONS

The primary findings are that the system accuracy of OD HMARSN systems is seriously affected by a transformation between the spaces of the user's eyes and the surgical field, because measurement of the transformation is heavily individualized and user-dependent. Additionally, the transformation itself is potentially subject to changes during surgical procedures, and hence unstable. Therefore, OD HMARSN systems are not suitable for large-scale clinical deployment.

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∘ and 0.37±0.11∘ , 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∘ (95% CI [0.33-0.35]) and 0.40±0.31∘ (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.

[Clinical application standard of dynamic navigation technology in implant surgery]

Dynamic navigation technology can "real-time guide" the implantologist to place the implant in the alveolar bone of the missing tooth area according to the preoperative design of the optimal site and path, making the whole implant surgery process more safe and precise. In order to further promote the standardized application of oral implant dynamic navigation technology, China Association of Gerontology and Geriatrics has convened distinguished experts to engage in deliberations and develop the standard. This standard covers the basic requirements, indications and contraindications, operation procedures, common complications and treatment measures, and accuracy verification. This standard can be used as a reference for the use of dynamic navigation technology in implant surgery.