The zLOCK Lumbar Facet Fixation System is an integrated construct comprised of a modular spacer and a single facet screw. The system is intended for temporary stabilization of the spine as an adjunct to fusion through bilateral immobilization of the facet joints in skeletally mature patients.

The zLOCK Lumbar Facet Fixation System is intended for use as an adjunct to a 1-level interbody lumbar fusion from L3 to L5 with autogenous and/or allogenic bone graft and must be accompanied by an FDA cleared intervertebral body fusion device implanted at the same spinal level. The zLOCK Lumbar Facet Fixation System is indicated for the treatment of patients with lumbar degenerative disc disease at a single level from L3 to L5 in skeletally mature patients who have failed conservative care.

Device Description

The zLOCK Lumbar Facet Fixation System is composed of a modular spacer and facet screws as an integrated construct to achieve posterior lumbar facet fixation as an adjunct to fusion. All implants are supplied sterile for single use only. The modular spacers are available in one footprint with a variety of heights to accommodate varying anatomical conditions of the patient, contain a screw hole, and are bendable with toothed surfaces to firmly anchor into the joint space and contain bone graft. The facet screw is cannulated, self-tapping, with a preassembled polyaxial washer; it is provided in one size. The modular spacer and facet screw are manufactured from Titanium Grade 1 and Titanium 6Al 4V alloy, respectively.

The system is supplied with a set of non-sterile, reusable instruments to access the site, prepare it for implantation, and perform device implantation.

AI/ML Overview

This document describes the zLOCK Lumbar Facet Fixation System, a medical device, and its acceptance criteria as demonstrated through non-clinical and clinical performance testing.

1. Table of Acceptance Criteria and Reported Device Performance

The provided text details the non-clinical and clinical studies conducted but does not explicitly state numerical acceptance criteria with corresponding device performance metrics in a readily extractable table format. Instead, it describes the types of tests performed and concludes that the device "supports substantial equivalence to predicate devices" and that clinical data "supports there are no increased safety or effectiveness concerns compared to predicates."

To present this in a structured table, we'll infer the acceptance criteria from the nature of the tests and the general goal of demonstrating substantial equivalence. The reported performance is qualitative, indicating the device met the implied benchmarks for substantial equivalence.

Acceptance Criteria Type	Implied Acceptance Standard	Reported Device Performance
Non-Clinical Performance Testing
Screw Testing per ASTM F543:	Device performance (static axial pullout, torsional strength, insertion/removal) should be comparable to or better than predicate devices and meet relevant standards for spinal implants.	Non-clinical testing "supports substantial equivalence to predicate devices."
- Static axial pullout test
- Torsional strength test
- Insertion and removal tests
Modular Spacer Testing per ASTM F2077:	Device performance (static/dynamic axial compression, static/dynamic compression-shear) should be comparable to or better than predicate devices and meet relevant standards for intervertebral body fusion devices.	Non-clinical testing "supports substantial equivalence to predicate devices."
- Static and dynamic axial compression
- Static and dynamic compression-shear
Biomechanical study in cadaveric specimens	Biomechanical stability and performance in a cadaveric model should be comparable to or better than predicate devices and demonstrate appropriate stabilization.	Non-clinical testing "supports substantial equivalence to predicate devices."
Finite Element Analysis (FEA)	FEA should confirm that shear forces on the device are within acceptable limits for the intended use and comparable to predicate devices, demonstrating structural integrity and safety.	Non-clinical testing "supports substantial equivalence to predicate devices."
Clinical Performance Data
Radiographic and CT evaluations	Radiographic fusion and stability should be demonstrated, comparable to outcomes of predicate devices or established clinical success for lumbar fusion, with no increased safety concerns.	Clinical data "supports there are no increased safety or effectiveness concerns compared to predicates when used for lumbar facet fixation."
Safety data	Incidence of adverse events should be acceptable and comparable to predicate devices or established safety profiles for similar procedures, with no increased safety concerns.	Clinical data "supports there are no increased safety or effectiveness concerns compared to predicates when used for lumbar facet fixation."
Patient Reported Outcomes (PROs)	Improvement in Oswestry Disability Index (ODI) and Visual Analog Scale (VAS) for back and leg pain should be observed, consistent with clinically meaningful improvement seen with predicate devices or standard of care for lumbar fusion, with no increased effectiveness concerns.	Clinical data "supports there are no increased safety or effectiveness concerns compared to predicates when used for lumbar facet fixation." (implies effectiveness is comparable)

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

Sample Size for Test Set: The document does not explicitly state the specific number of patients included in the clinical study. It refers to a "prospective, multi-center single arm interventional study."
Data Provenance: The clinical study was conducted "outside the United States." It was a "prospective" study, meaning data was collected forward in time specifically for this research.

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

The document does not provide information on the number or qualifications of experts used to establish a ground truth for the clinical test set. It mentions "radiographic and CT evaluations" were used, but not who interpreted them or how consensus was reached.

4. Adjudication Method for the Test Set

The document does not specify any adjudication method (e.g., 2+1, 3+1) used for the clinical test set.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

No Multi-Reader Multi-Case (MRMC) comparative effectiveness study was mentioned. The clinical study was described as a "single arm interventional study," meaning there was no direct comparison between AI assistance and unassisted human readers, or between human readers with and without the device's specific outputs. The device itself is a surgical implant, not an AI or imaging diagnostic tool that would typically involve a MRMC study for assessing reader performance.

6. Standalone (Algorithm Only Without Human-in-the-Loop Performance) Study

Not applicable. The zLOCK Lumbar Facet Fixation System is a physical implant, not a software algorithm or diagnostic tool. Therefore, a "standalone algorithm-only" performance study is not relevant to this device.

7. Type of Ground Truth Used

For the non-clinical tests, the "ground truth" would be the engineering specifications, material properties, and biomechanical parameters established by the ASTM standards and finite element analysis models.

For the clinical data, the ground truth for safety and effectiveness was established through:

Radiographic and CT evaluations: These provided objective imaging evidence of fusion and device placement/stability.
Safety data: Collection of adverse events.
Patient Reported Outcomes (PROs): Subjective measures like Oswestry Disability Index (ODI) and Visual Analog Scale (VAS) for back and leg pain.

These measures collectively served as the basis for evaluating the device's performance against the implicit "ground truth" of no increased safety or effectiveness concerns compared to predicate devices.

8. Sample Size for the Training Set

Not applicable. This device is a physical medical implant, not a machine learning or AI algorithm that requires a training set in the typical sense.

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

Not applicable, as there is no "training set" for this type of medical device.

Summary

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April 18, 2024

ZygoFix, Ltd. % Justin Eggleton Vice President MCRA, LLC 803 7th Street NW Washington, District of Columbia 20001

Re: K240085

Trade/Device Name: zLOCK Lumbar Facet Fixation System Regulatory Class: Unclassified Product Code: MRW Dated: March 21, 2024 Received: March 22, 2024

Dear Justin Eggleton:

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 (the 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 available 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.

Additional information about changes that may require a new premarket notification are provided in the FDA guidance documents entitled "Deciding When to Submit a 510(k) for a Change to an Existing Device" (https://www.fda.gov/media/99812/download) and "Deciding When to Submit a 510(k) for a Software Change to an Existing Device" (https://www.fda.gov/media/99785/download).

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Your device is also subject to, among other requirements, the Quality System (QS) regulation (21 CFR Part 820), which includes, but is not limited to, 21 CFR 820.30, Design controls; 21 CFR 820.90, Nonconforming product; and 21 CFR 820.100, Corrective and preventive action. Please note that regardless of whether a change requires premarket review, the QS regulation requires device manufacturers to review and approve changes to device design and production (21 CFR 820.30 and 21 CFR 820.70) and document changes and approvals in the device master record (21 CFR 820.181).

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 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 Part 803) for devices or postmarketing safety reporting (21 CFR Part 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 Part 4, Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR Parts 1000-1050.

Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR 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 mediation-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,

Image /page/1/Picture/6 description: The image contains the text "Colin O'neill -S" in a simple, sans-serif font. The text is arranged vertically, with "Colin" on the top line and "O'neill -S" on the bottom line. To the right of the text is a faded logo that appears to be "FDA".

Colin O'Neill, M.B.E. Assistant Director DHT6B: Division of Spinal Devices OHT6: Office of Orthopedic Devices Office of Product Evaluation and Quality Center for Devices and Radiological Health

Enclosure

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Indications for Use

Submission Number (if known)

K240085

Device Name

zLOCK Lumbar Facet Fixation System

Indications for Use (Describe)

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

Prescription Use (Part 21 CFR 801 Subpart D)

he-Counter Use (21 CFR 801 Subpart C)

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510(k) Summary

Trade Name:	zLOCK Lumbar Facet Fixation System
Manufacturer:	Zygofix, Ltd.17 T'helet St.Misgay Business ParkMisgay M.P.2017400, Israel
Sponsor Contact:	Ofer LevyChief Executive Officer
Prepared by:	Justin EggletonMCRA, LLC803 7th Street, NW, 3rd FloorWashington, DC 20001Office: 202.552.5800
Date Prepared:	March 7, 2024
Classification:	Unclassified
Product Codes:	MRW; System, Facet Screw Spinal Device
Primary Predicate:	PrimaLOK Facet Fixation System (K102438)
Additional Predicate:	PMT Facet Fixation System, Lumbar (PMT FFS-LX) (K230840)
Reference Device:	PMT Facet Fixation System (K220951)

Device Description:

The system is supplied with a set of non-sterile, reusable instruments to access the site, prepare it for implantation, and perform device implantation.

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Indications For Use:

The zLOCK Lumbar Facet Fixation System is intended for use as an adjunct to a 1-level interbody lumbar fusion from L3 to L5 with autogenous and/or allogenic bone graft and must be accompanied by an FDA cleared intervertebral body fusion device implanted at the same spinal level. The zLOCK Lumbar Facet Fixation System is indicated for the treatment of patients with lumbar degenerative disc disease at a single level from 13 to 15 in skeletally mature patients who have failed conservative care.

Predicate Device:

The zLOCK Lumbar Facet Fixation System is substantially equivalent in indications, design principles, and performance to the following legally marketed predicate devices:

Primary Predicate: PrimaLOK Facet Fixation System (K102438) Additional Predicate: PMT Facet Fixation System, Lumbar (PMT FFS-LX) (K230840) Reference Device: PMT Facet Fixation System (K220951)

Non-Clinical Performance Testing:

Non-clinical testing performed on the subject zLOCK Lumbar Facet Fixation System supports substantial equivalence to predicate devices. The following testing were presented:

Screw Testing per ASTM F543: ●
- o Static axial pullout test
- o Torsional strength test
- Insertion and removal tests o
Modular Spacer Testing per ASTM F2077:
- о Static and dynamic axial compression
- O Static and dynamic compression-shear
. Biomechanical study in cadaveric specimens
Finite Element Analysis to evaluate shear forces

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Clinical Data:

Clinical data from a prospective, multi-center single arm interventional study outside the United States was presented. Patients implanted with the zLOCK Lumbar Facet Fixation System Modular Spacer were evaluated using radiographic and CT evaluations, safety data, and patient reported outcomes (Oswestry Disability Index and visual analog scale for back and leg pain). For the proposed indications for use, the clinical data on the zLOCK device supports there are no increased safety or effectiveness concerns compared to predicates when used for lumbar facet fixation.

Substantial Equivalence:

The zLOCK Lumbar Facet Fixation System is substantially equivalent to legally marketed predicate devices in terms of its technological characteristics, intended use, and mechanical performance. The zLOCK Facet Screw is nearly identical to the primary predicate except for a minor difference in thread geometry. The zLOCK construct, consisting of a Modular Spacer with Facet Screw, has the same principles of operation as the predicate devices.

Conclusion:

The subject device and the predicate devices have intended use, have similar technological characteristics, and are made of similar materials. The subject and predicate devices are packaged in similar materials and are sterilized using similar methods. The data included in this submission demonstrate substantial equivalence to the predicate devices listed above.

Regulation Number and Section

N/A