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Caduceus S is intended as an aid for precisely locating anatomical structures in percutaneous spine procedures. It is indicated for medical conditions in which the use of stereotactic surgery may be appropriate, when reference to a rigid anatomical structure, such as the spine or pelvis, can be identified relative to CT or 2D/3D C-arm images of the anatomy. This can include the spinal implant procedures, such as Posterior Pedicle Screw Placement in the thoracic and lumbosacral spine. Caduceus S offers pedicle screw implant size planning and navigation on rigid bone structures with intraoperatively registered surgical Instruments. The Headset of the Caduceus S displays 2D stereotaxic screens and a 3D anatomy model (floating). The displayed stereotaxic screens are indicated for correlating the tracked instrument location to the patient registered imagery to assist in percutaneous visualization and trajectory planning.

The Caduceus S system is an image-guided navigation system that is designed to assist surgeons in placing pedicle screws accurately, during percutaneous computer-assisted spinal surgery. The system consists of a dedicated software, Navigation Cart, Navi Tracker, Headset, Minimally Invasive Spine Surgery Instruments, Disposable Passive Spheres, and other disposable surgical consumables. It uses optical tracking technology and displays to the surgeon the location of the tracked surgical instruments relative to the acquired intraoperative patient's scan, onto the surgical field. The 2D scanned data and 3D reconstructed model, along with tracking information, are projected to the surgeons' eyes using a transparent near-eye-display Headset, allowing the surgeon to both look at the patient and the navigation data at the same time.

Here's a breakdown of the acceptance criteria and study information based on the provided text:

1. Table of Acceptance Criteria and Reported Device Performance

The provided text does not explicitly state acceptance criteria in a quantitative table format with corresponding performance results. Instead, it lists the types of tests performed and generally concludes that they were "successfully completed" or that the device "performs according to specifications and functions as intended."

However, we can infer the tested parameters and the general outcome:

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

• Cadaver Studies: "three cadaver studies" were performed. The exact number of cadavers or individual screw placements is not specified.
• Human Factors: "Test participants representing the intended users" – the number of participants is not specified.
• Data Provenance: The document does not explicitly state the country of origin for the cadaver studies or human factors testing. It also doesn't specify if these were retrospective or prospective studies, though cadaver studies are inherently prospective for device testing.

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

The document does not specify the number or qualifications of experts used to establish ground truth for the cadaver studies. It mentions that clinical accuracy was evaluated using the Gertzbein-Robbins score by viewing post-op scans, which implies expert review, but details are absent.

4. Adjudication Method for the Test Set

The document does not describe any specific adjudication method (e.g., 2+1, 3+1) for establishing ground truth or evaluating the test set results. The Gertzbein-Robbins score evaluation, while involving expert review, doesn't detail an adjudication process.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, and Effect Size

No, the provided text does not indicate that a Multi-Reader Multi-Case (MRMC) comparative effectiveness study was done. Therefore, no effect size of human readers improving with AI vs. without AI assistance is reported. The study primarily focuses on the device's standalone performance and accuracy.

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

Yes, standalone performance was assessed for various aspects of the device. For example:

• "Performance of the Headset display was demonstrated by verifying the following elements: Resolution, luminance, transmission, distortion, contrast ratio and latency."
• "Electrical safety was tested..."
• "Electromagnetic Compatibility (EMC) was tested..."
• "Repeatability and accuracy were tested according to ASTM F2554."
• "The system's accuracy was validated in three cadaver studies, in which screws were positioned in the positional and trajectory errors were calculated..." (This assesses the system's accuracy in guiding screw placement before considering human interpretation of the guidance).

The human factors study involved human interaction, but the underlying system accuracy tests are more akin to standalone performance evaluations.

7. The Type of Ground Truth Used

• Cadaver Studies: The ground truth for the cadaver studies involved "calculat[ing] the difference between the actual and virtual screw tip position, and the difference between the screw orientation and its recorded virtual trajectory." This implies a comparison against actual physical screw placement (measured by some means, likely post-placement imaging or direct measurement) versus the intended/navigated virtual trajectory. Additionally, "clinical accuracy was evaluated using the Gertzbein-Robbins score by viewing the post-op scans," suggesting radiological or surgical expert consensus based on image review as a ground truth for clinical relevance.
• Hardware and Software Performance: Ground truth was established by comparing device output (e.g., resolution, latency, electrical parameters) against engineering specifications, industry standards (IEC, EN), and regulatory guidance.

8. The Sample Size for the Training Set

The document does not provide any information regarding the sample size used for the training set. This section of the submission focuses on verification and validation testing, not algorithm training.

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

Since no information on a training set is provided, there is no information on how its ground truth was established.

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Caduceus S is intended as an intraoperative gudance system to enable minimally invasive surgery. Intraoperatively registered surgical Instruments are tracked by a passive marker sensor system to virtual computer image space on a patient's preoperative or intraoperative 2D or 3D image data.

Caduceus S enables image-guide navigation of medical image data, which can either be acquired preoperatively CT or intraoperatively C-arm by an appropriate image acquisition system.

Caduceus S offers pedicle screw implant size planning and navigation on rigid bone structures with intraoperatively registered surgical Instruments.

Caduceus S is indicated for L5~T6 spine surgery where reference to a rigid anatomical structure can be identified relative to the acquired patient imagery (CT or C-arm).

The headset (Surglasses) of the Caduceus S system is an optional heads up display that projects the 2D stereotaxic screens of the system's display.

Caduceus S surgical navigation system is an image guidance system, which is composed of Navi Tracker, Surglasses, other hardware (Navigation Cart with an arm, Touch Screen, Router, Control System, Connection System), disposable tools (Disposable Passive Sphere, Straight Guide Pin, Navi Clamp Kit, Instrument Adapter Type A&B, Calibration Plate, Registration Kit, Correction Tool), reusable tools (Calibration Board, Instrument Holder), and Spine Navigation Software. Caduceus S is an optical tracking and guiding system for spine surgery. It can track the marks on the surgical instruments and patient's anatomical structure with marks, and register with the preoperative or intraoperative images of the patients. During the surgery, it can be displayed on the Touch Screen and the head mounted display Surglasses to provide the navigation for the surgical instruments.

Here's a breakdown of the acceptance criteria and the study proving the Caduceus S device meets them, based on the provided FDA 510(k) summary:

Acceptance Criteria and Device Performance

The core performance validation for this device, a surgical navigation system, relates to its accuracy in positioning and trajectory. The summary explicitly states:

*UBL = Upper Bound Limit (This indicates the upper limit of the confidence interval for the measured error, providing a statistical guarantee.)

Study Details

The primary study mentioned for evaluating device performance is a "System's accuracy" and "Performance and Usability of device intended use" study, which involved both phantom and cadaver studies.

1. Sample Size and Data Provenance:

   • Test Set Sample Size: The exact number of pedicle screws positioned or cases in the cadaver study is not explicitly stated as a number of subjects/specimens, but it mentions pedicle screws were positioned in L5-T6 spine. The testing was conducted in both "phantom and cadaver studies."
   • Data Provenance: The document does not specify the country of origin for the cadaver data. It states the studies were non-clinical. The studies were retrospective in the sense that they were pre-market validation studies using pre-existing materials (phantoms, cadavers) to simulate real-world conditions.

2. Number of Experts and Qualifications for Ground Truth:

   • The document does not specify the number of experts used to establish the ground truth or their specific qualifications. It mentions that the positional error was derived from the "post-op scan" and its virtual tip as recorded by the Caduceus S system. This suggests the ground truth was established by comparing system output to a precise post-procedure imaging measurement.

3. Adjudication Method:

   • The document does not describe an adjudication method involving multiple human readers for the test set. The ground truth appears to be based on direct measurement from post-operative imaging.

4. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study:

   • No MRMC comparative effectiveness study was done. The submission explicitly states: "No clinical test data was used to support the decision of substantial equivalence." This means no study was performed comparing human readers with and without AI assistance to measure improvement. The device is purely an intraoperative guidance system, and its validation focuses on its technical accuracy rather than interpretive diagnostic performance.

5. Standalone Performance Study:

   • Yes, a standalone study was performed. The described "System's accuracy" assessment is a standalone evaluation of the algorithm's output (positional and angular error) against the established ground truth (derived from post-op scans). This is algorithm-only performance without a human-in-the-loop directly influencing the measured accuracy metrics.

6. Type of Ground Truth Used:

   • The ground truth was established by measurements obtained from post-operative imaging (post-op scan). Specifically, for positional error, it was the difference between the actual screw tip position derived from the post-op scan and the system's recorded virtual tip. For trajectory error, it was the difference between the screw orientation and its recorded virtual trajectory. This closely aligns with "outcomes data" or highly precise "imaging-based comparison."

7. Training Set Sample Size:

   • The document does not specify the sample size used for the training set. This is a common omission in 510(k) summaries, as the focus is on the validation of the final device, not the development process.

8. Ground Truth Establishment for Training Set:

   • The document does not provide details on how ground truth was established for any training set. Given the nature of a 510(k) submission and the device (a surgical navigation system rather than a diagnostic AI), details on training data are typically less prominent in the publicly available summary unless directly relevant to a novel AI methodology requiring extensive clinical data for training. The performance validation relies on the non-clinical bench and cadaver studies.

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