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The VisAR System is intended as an aid for precisely locating anatomical structures in either open or percutaneous spine procedures. VisAR is indicated for any medical condition in which the use of stereotaxic surgery may be appropriate, and where reference to at least one rigid anatomical structure, such as the spine or iliac crests, can be identified relative to CT imagery of the anatomy. This can include guidance for procedures, such as Posterior Pedicle Screw Placement in the thoracic and sacro-lumbar region.

VisAR displays a virtual screen for stereoscopic 3D images acquired from CT sources. It is intended to enable users to segment previously acquired 3D datasets, overlay, and register these 3D segmented datasets with the anatomy of the patient in order to support intraoperative analysis and guidance.

The virtual screen is indicated for displaying the virtual instrument location to the virtual anatomy to assist in visualization and trajectory planning for both open and percutaneous surgeries.

The VisAR system is an image-guided navigation system that is designed to assist surgeons in placing pedicle screws accurately, during open or percutaneous spinal surgery. The system consists of Novarad's immersive augmented reality software running on the Microsoft Hololens 2 headset, image visible ARTags (AprilTags), a pre-operative planning workstation and the Novarad PACS server. It uses optical tracking technology to co-localize the virtual 3D image datasets to the patient and displays to the surgeon the location of pre-operatively planned operative tracks and the tracked surgical instruments relative to the acquired intraoperative patient's scan, onto the surgical field. The 3D scanned image, along with tracking information, are projected to the surgeons' retina using a transparent near-eye display stereoscopic headset, allowing the surgeon to both look at the navigation data at the same time.

Here's a summary of the acceptance criteria and the study proving the device meets them, based on the provided text:

1. Table of Acceptance Criteria and Reported Device Performance

2. Sample Size Used for the Test Set and Data Provenance

• Sample Size (Accuracy Testing): 7 cadavers; 124 pedicle screws inserted.
• Data Provenance: Not explicitly stated, but the use of cadavers implies the data is retrospective for the purpose of the study (performed in a lab setting rather than on live patients). The testing was conducted in the context of the device manufacturer (Novarad, Provo, Utah), suggesting a U.S. origin for the experimental setup.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts

• Number of Experts: One neuroradiologist, in addition to spine surgeons who performed the insertions.
• Qualifications of Experts: The ground truth for preoperative planning (pedicle entry point, trajectory, and depth) was established by a neuroradiologist. Spine surgeons used the device for screw insertion. The comparison of actual screw placement to planned pathways was done by fusing pre- and post-operative CT scans.

4. Adjudication Method for the Test Set

The provided text does not explicitly detail an external adjudication method (e.g., 2+1, 3+1). The accuracy evaluation involved:

1. A neuroradiologist annotating preoperative CT images for planned screw placement.
2. Spine surgeons performing the screw insertions using VisAR.
3. Comparison of the actual screw placement (from postoperative CT) to the annotated virtual pathway (from preoperative CT) using vector coordinates.
4. Evaluation using the Gertzbein-Robbins scale.
   This process indicates an internal comparison against a pre-established plan rather than an external adjudication of the device's output by multiple independent experts.

5. If a Multi Reader Multi Case (MRMC) Comparative Effectiveness Study was done

No, a multi-reader multi-case (MRMC) comparative effectiveness study was not explicitly mentioned or described. The study focused on the standalone accuracy of the device in cadaveric models. The text explicitly states: "There are no clinical tests to compare VisAR and predicate device system (XVS), as they are software products that retrieve and display images and information."

6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was done

Yes, the accuracy testing described in the "Performance Data" section represents a standalone performance evaluation of the device's guidance capabilities when used by surgeons. While surgeons were "in the loop" for inserting screws, the metrics (positional error, trajectory angle error, Gertzbein-Robbins scale) evaluate the device's accuracy in guiding those surgeons relative to a pre-planned trajectory, not a comparison against unassisted human performance.

7. The Type of Ground Truth Used

The ground truth for the accuracy study was a combination of:

• Expert Consensus/Annotation: Preoperative plans (pedicle entry point, trajectory, depth) were determined and annotated by a neuroradiologist on CT images.
• Reference standard (Post-operative imaging): The actual screw placement was determined from postoperative CT scans, which were then fused with the preoperative CT scans to spatially compare the actual placement against the neuroradiologist's annotated virtual pathway.
• Clinical Scale: The Gertzbein-Robbins scale was also used for assessment of screw placement, which is a common clinical measurement.

8. The Sample Size for the Training Set

The document does not provide any information regarding the sample size used for the training set of the VisAR system's algorithms.

9. How the Ground Truth for the Training Set was Established

The document does not provide any information on how the ground truth for the training set was established.

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