The Bolt Navigation System assists in the accurate placement of pedicle screws when used in conjunction with an intraoperative fluoroscope. It utilizes intraoperative fluoroscopic and pre- operative MRI or CT axial images to provide surgical planning and navigational telemetry relative to gravity, based on a fixed entry point ascertained by the user and validated by intraoperative fluoroscopic imaging. It is not intended to track patient position. The System is indicated for open and minimally invasive pedicle screw placement using a posterior approach in the thoracolumbar and sacral spine (T-9 to S1) where the patients' relevant rigid anatomical structures can be clearly identified on the imaging.

Device Description

The BNS is comprised of the Bolt Navigation Unit (BNU) (an iPod touch® mobile digital device with the Bolt navigation software loaded on it), the Bolt single use case, and sterile drape. The BNS is intended to provide navigational guidance during spine surgery. The system uses preand perioperative imaging data, and input from the surgeon via the BNU touchscreen to construct the proper angular position of the instrumentation and implants relative to gravity, and communicates this information to the surgeon via the BNU screen attached to the instrument allowing the surgeon to look at both the surgical site and the navigation data at the same time, thus attenuating the risk of attention shift. The BNS provides guidance data by displaying the angular orientation of a surgical instrument (such as a pedicle probe or awl) relative to a surgeon selected entry point on the patient and gravity. Angular orientation of the instruments is linked to the imaging data via the BNS. The system is intended to be used for both image fusion and navigation for spine surgery applications where reference to relevant rigid structures can be identified relative to a perioperative image data of the anatomy and the gravity vector.

AI/ML Overview

Here's an analysis of the acceptance criteria and study details for the Bolt Navigation System ("BNS"), based on the provided FDA 510(k) summary:

Acceptance Criteria and Device Performance

Acceptance Criteria	Reported Device Performance
Overall angle accuracy performance (with a 95% CI) statistically significantly lower than 3 degrees.	A mean accuracy error of 1.59° with a 95% CI of [1.31°, 1.86°] for the parametric analysis, and a median accuracy error of 1.78° with a 95% CI of [1.62°, 2.12°] for the non-parametric analysis. Both are statistically significantly lower than 3 degrees.
Clinical phantom accuracy (95% CI of Individuals)	0.69° (95% CI of Individuals) for phantom accuracy.

Study Details

Sample size used for the test set and the data provenance:
- Test Set (Cadaveric Trajectory Accuracy Study): The document doesn't explicitly state the number of cadavers or individual screw placements used in the cadaveric study. However, the results are presented as overall accuracy, testing levels T9 to S1 (thoracolumbar and sacral spine).
- Data Provenance: The cadaveric study is a non-clinical test, implying it was conducted in a controlled lab setting, likely in the country of the manufacturer or test facility. It is a prospective study in the sense that the data was generated specifically for this validation.
Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- The document does not provide information on the number of experts or their qualifications used to establish ground truth for the cadaveric study.
- For the cadaveric study, "Planned trajectory vs actual placement accuracy" was assessed, but the method for determining "actual placement" (e.g., post-insertion imaging, dissection measurement) and who evaluated it is not detailed.
Adjudication method (e.g., 2+1, 3+1, none) for the test set:
- The document does not specify an adjudication method for the cadaveric study.
If a multi-reader multi-case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance:
- A formal MRMC comparative effectiveness study, comparing human readers with and without AI assistance, was not explicitly detailed in the provided summary.
- A "multi-surgeon clinical study" was conducted, but its results are only summarized as supplementary information to show the device performs as intended, not as a comparative effectiveness study against a non-AI control group with quantifiable improvement.
If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:
- The "Clinical phantom accuracy results" represent a standalone performance assessment of the system against a known phantom, demonstrating the system's inherent accuracy in a controlled environment. The mean accuracy was 0.35 degrees.
- The "Cadaveric accuracy results" also reflect the algorithm's performance in a more realistic surgical simulation, where surgical instruments guided by the BNS were evaluated for accuracy of placement against a planned trajectory. While a human surgeon uses the system, the
- accuracy measurement itself quantifies the system's guidance.
The type of ground truth used (expert consensus, pathology, outcomes data, etc):
- Clinical Phantom Accuracy: The ground truth for the phantom study would be the known, precisely manufactured dimensions and orientations of the phantom, which the device is designed to measure.
- Cadaveric Trajectory Accuracy Study: The ground truth for this study is described as "Planned trajectory vs actual placement accuracy." The "planned trajectory" would be established pre-procedure (likely by a surgeon using imaging), and the "actual placement" would be measured post-procedure using a precise method (e.g., high-resolution CT, C-arm imaging, or physical measurement) to determine the deviation from the plan. The specific method for determining "actual placement" (which serves as the "truth") is not detailed.
The sample size for the training set:
- The document does not provide information on the sample size of any training set used for the BNS software. The BNS utilizes "pre- and perioperative imaging data" and "intraoperative fluoroscopic and pre-operative MRI or CT axial images," suggesting it may rely on existing imaging data for its functionality, but details about supervised machine learning training, if any, are absent.
How the ground truth for the training set was established:
- Since the document does not specify a training set or the use of machine learning that would require a distinct training set with ground truth, this information is not available. The system appears to be more of a navigation system based on physical principles and image registration rather than a deep learning model requiring extensive annotated training data.

Summary

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December 1, 2022

Circinus Medical Technology, LLC % Alex Cadotte Associate Director, Software & Digital Health MCRA, LLC 803 7th St., NW, 3rd Floor WASHINGTON DC 20001

Re: K213768

Trade/Device Name: Bolt Navigation System ("BNS") Regulation Number: 21 CFR 892.1650 Regulation Name: Image-Intensified Fluoroscopic X-Ray System Regulatory Class: Class II Product Code: OWB Dated: October 18, 2022 Received: October 27, 2022

Dear Alex Cadotte:

We have reviewed your Section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. Although this letter refers to your product as a device, please be aware that some cleared products may instead be combination products. The 510(k) Premarket Notification Database located at https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm identifies combination product submissions. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.

If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. In addition, FDA may publish further announcements concerning your device in the Federal Register.

Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal

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statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Part 801); medical device reporting of medical device-related adverse events) (21 CFR 803) for devices or postmarketing safety reporting (21 CFR 4, Subpart B) for combination products (see https://www.fda.gov/combination-products/guidance-regulatory-information/postmarketing-safety-reportingcombination-products); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820) for devices or current good manufacturing practices (21 CFR 4, Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.

Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR Part 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to https://www.fda.gov/medical-device-safety/medical-device-reportingmdr-how-report-medical-device-problems.

For comprehensive regulatory information about medical devices and radiation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/medicaldevices/device-advice-comprehensive-regulatory-assistance) and CDRH Learn (https://www.fda.gov/training-and-continuing-education/cdrh-learn). Additionally, you may contact the Division of Industry and Consumer Education (DICE) to ask a question about a specific regulatory topic. See the DICE website (https://www.fda.gov/medical-device-advice-comprehensive-regulatoryassistance/contact-us-division-industry-and-consumer-education-dice) for more information or contact DICE by email (DICE@fda.hhs.gov) or phone (1-800-638-2041 or 301-796-7100).

Sincerely,

2022.12.01
11:54:38
-05'00'
Lu Jiang

Lu Jiang, Ph.D. Assistant Director Diagnostic X-Ray Systems Team DHT8B: Division of Radiological Imaging Devices and Electronic Products OHT8: Office of Radiological Health Office of Product Evaluation and Ouality Center for Devices and Radiological Health

Enclosure

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Indications for Use

510(k) Number (if known) K213768

Device Name Bolt Navigation System ("BNS")

Indications for Use (Describe)

Type of Use (Select one or both, as applicable)

	Prescription Use (Part 21 CFR 801 Subpart D)
	Over-The-Counter Use (21 CFR 801 Subpart C)

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510(k) Summary	K213768
Device Trade Name:	Bolt Navigation System (“BNS”)
Common Name:	Image-intensified fluoroscopic X-ray system
Manufacturer:	Circinus Medical Technology, LLC4450 Arapahoe AvenueSuite 1000Boulder, CO 80303
Contact:	Mr. Patrick WestCircinus Medical Technology, LLCPhone: (207) 651-1334Email: patrick@boltnav.com
Prepared by:	MCRA, LLC1050 K Street NW, Suite 1000Washington, DC 20001Phone: (202) 552-5800
Date Prepared:	Oct 25, 2021
Classification:	21 CFR §892.1650
Class:	II
Product Codes:	OWB

Indications for Use:

The Bolt Navigation System assists in the accurate placement of pedicle screws when used in conjunction with an intraoperative fluoroscope. It utilizes intraoperative fluoroscopic and preoperative MRI or CT axial images to provide surgical planning and navigational telemetry relative to gravity, based on a fixed entry point ascertained by the user and validated by intraoperative fluoroscopic imaging. It is not intended to track patient position. The System is indicated for open and minimally invasive pedicle screw placement using a posterior approach in the thoracolumbar and sacral spine (T-9 to S1) where the patients' relevant rigid anatomical structures can be clearly identified on the imaging.

Device Description:

The BNS is comprised of the Bolt Navigation Unit (BNU) (an iPod touch® mobile digital device with the Bolt navigation software loaded on it), the Bolt single use case, and sterile drape. The

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BNS is intended to provide navigational guidance during spine surgery. The system uses preand perioperative imaging data, and input from the surgeon via the BNU touchscreen to construct the proper angular position of the instrumentation and implants relative to gravity, and communicates this information to the surgeon via the BNU screen attached to the instrument allowing the surgeon to look at both the surgical site and the navigation data at the same time, thus attenuating the risk of attention shift.

The BNS provides guidance data by displaying the angular orientation of a surgical instrument (such as a pedicle probe or awl) relative to a surgeon selected entry point on the patient and gravity. Angular orientation of the instruments is linked to the imaging data via the BNS.

The system is intended to be used for both image fusion and navigation for spine surgery applications where reference to relevant rigid structures can be identified relative to a perioperative image data of the anatomy and the gravity vector.

Predicate Device:

The Track X Technology, TrackX Device (K200360) serves as the primary predicate device. The Augmedics xvision Spine System (K190929) and the Medtronic StealthStation (K133444, K170011) serve as reference devices.

Technological Characteristics Comparison:

The BNS and its primary predicate technology are designed to aid the physician in positioning surgical instruments and placing implants by providing visual feedback on the movement of instruments relative to imaging data. Both systems use software platforms that allow for the surgeon to track the surgical instruments relative to the perioperative fluoroscopic images.

Both systems enable the surgeon to view the orientation of surgical instruments relative to that planned by the surgeon on preoperative image data while performing the surgical procedure with the aid of a fluoroscope. The systems provide guidance data by tracking and displaying orientation of the Spinal Instruments relative to a surgeon identified entry point and the gravity vector. Tracking data is linked to the preoperative imaging data.

Both systems are designed to work effectively with a range of 3rd party surgical instruments.

The BNS and the reference devices are designed to provide trajectory orientation guidance to the surgeon relative to relevant rigid anatomical structure with a performance goal of < 3°. These systems use software platforms that allow for the surgeon to match intraoperative trajectory to pre- and perioperative images and planning based on a surgeon identified entry-point. Both systems enable the surgeon to view the angular orientation of surgical instruments relative to that planned by the surgeon on preoperative image data while performing the surgical procedure. The BNS provides navigational guidance in three-degrees of freedom relative to a chosen entry point and the gravity vector while the reference devices (K190929, K133444, K170011), provide navigational guidance relative to a frame attached to the patient in six-degrees of freedom.

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Nonclinical Testing:

Verification/Validation activities and performance testing have been conducted to support that the subject device meets the performance requirements under the indications for use conditions and to support substantial equivalence to the predicate devices, including the following:

Sterilization, Cleaning, and Shelf-life Validation ●
Biocompatibility Evaluation ●
Non-Clinical Software Documentation and Verification
Non-Clinical Cybersecurity Evaluation
Electrical safety and EMC testing (IEC 60601-1 and IEC 60601-1-2) ●
Usability Validation testing per IEC 62366-1: 2015, IEC 62366-2ANSI/AAMA HE75 ● and FDA Guidance for Industry and FDA Staff, including a Surgeon- Performed Cadaveric Study
Non-Clinical Accuracy Testing per ASTM F2554-10 ●
Cadaveric Trajectory Accuracy Study, based on a protocol that was discussed and reviewed by FDA via Submission Issue Request on July 12, 2022(Q220500/S001)

Clinical phantom accuracy results

Mean	Std.Deviation	95% CIof Mean	95% CIof Individuals	99% CIof Mean	99% CIof Individuals
0.35°	0.20°	0.39°	0.69°	0.41°	0.82°

CI (Confidence Interval)

Cadaveric accuracy results

Planned trajectory vs actual placement accuracy (< 3 ° / 95% CI)

	Estimate	2-sided95% CI LB	2-sided95% UB	1-sided95% UB
Parametric*	1.59	1.31	1.86	1.81
Non-Parametric+	1.78	1.62	2.12	2.07
Notes:* Overall mean accuracy error estimate and 2-sided 95% CI and 1-sided 95% CI based on t-studentdistribution.+ Overall median accuracy error estimate and non-parametric distribution-free (bootstrap) 2-sided 95%CI and 1-sided 95% CI.Testing included levels T9 to S1.

CI (Confidence Interval)

The analysis demonstrates that source-specific variability is small and the overall angle accuracy performance with a mean of 1.59° with a 95% CI of being statistically significantly lower than 3 degrees.

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Clinical Testing:

Circinus has conducted a multi-surgeon clinical study. A summary report for this study has been included at the request of the FDA and is intended as supplementary information for the Agency's reference and to provide the Agency further evidence that the subject device performs as intended in its intended clinical application.

Conclusion:

The BNS is substantially equivalent to the predicate device(s) with respect to its indications for use, design, and function.

Regulation Number and Section

§ 892.1650 Image-intensified fluoroscopic x-ray system.

(a)
Identification. An image-intensified fluoroscopic x-ray system is a device intended to visualize anatomical structures by converting a pattern of x-radiation into a visible image through electronic amplification. This generic type of device may include signal analysis and display equipment, patient and equipment supports, component parts, and accessories.(b)
Classification. Class II (special controls). An anthrogram tray or radiology dental tray intended for use with an image-intensified fluoroscopic x-ray system only is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 892.9. In addition, when intended as an accessory to the device described in paragraph (a) of this section, the fluoroscopic compression device is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 892.9.