The Xenix Medical RIVA Posterior Fixation System is intended to provide immobilization and stabilization of spinal segments in skeletally mature patients as an adjunct to fusion as a pedicle screw fixation system or anterolateral fixation, in the treatment of the following acute and chronic instabilities or deformities of the thoracic, lumbar, and/or sacral spine:

Degenerative disc disease (defined as discogenic back pain with degeneration of the disc confirmed by history and radiographic studies).
Spondylolisthesis
Trauma (i.e. fracture or dislocation).
Spinal Stenosis
Deformities or curvatures (i.e scoliosis, kyphosis, and/or lordosis)
Tumor
Pseudoarthrosis
Failed previous fusion

Xenix Medical fenestrated screws are intended to be used with saline or radiopaque dye.

Xenix Medical RIVA Posterior Fixation System Navigation Instruments are intended to be used with the Xenix Medical RIVA Posterior Fixation System during surgery to assist the surgeon in precisely locating anatomical structures in either open or minimally invasive procedures. These instruments are designed for use with the Medtronic® StealthStation™ S8 System, in which the use of stereotactic surgery may be appropriate, and where reference to a rigid anatomical structure, such as the vertebra, can be identified relative to a CT or MRI based model, fluoroscopy images, or digitized landmarks of the anatomy.

Device Description

The Xenix Medical RIVA Posterior Fixation System is a non-cervical spinal fixation system used to build constructs within the body to act as temporary or permanent non-cervical spinal fixation devices and is intended for use as a posterior pedicle screw fixation system, and/or an anterolateral fixation system to correct spinal disorders and provide stabilization of the spine to permit the biological process of spinal fusion to occur.

The Xenix Medical RIVA Posterior Fixation System includes a variety of single-use implants manufactured from titanium alloy (Ti-6Al-4V ELI per ASTM F136) and/or cobalt chrome alloy (Co-28Cr-6Mo per ASTM F1537 or Co-35Ni-20Cr-10Mo per ASTM F562) and is comprised of polyaxial pedicle screws, as well as connecting spinal rods, connectors, crossbars, and a separate set screw locking element. The instruments included in the Xenix Medical RIVA Posterior Fixation System facilitate the placement, adjustment, final locking, and removal, if necessary, of the system implants, and accessories to the system include trays and caddies for storage, protection, and organization prior to and during the steam sterilization process.

AI/ML Overview

This document, a 510(k) Clearance Letter for the RIVA Posterior Fixation System, is a submission for a physical medical device (pedicle screw system and navigation instruments), not a software or AI-driven medical device. Therefore, the specific information requested in your prompt regarding acceptance criteria and study proving performance for AI/software-based devices (such as statistical metrics, test/training sets, expert consensus, MRMC studies) cannot be directly derived from this document.

The document focuses on proving substantial equivalence to existing predicate devices, primarily through mechanical performance testing for the physical implants and accuracy testing for the navigation instruments. It does not describe a clinical study in the way an AI/software device would.

However, I can extract and interpret the available information to best fit your requested structure, making assumptions where necessary based on typical 510(k) submissions for physical devices:

Analysis of Acceptance Criteria and Performance for RIVA Posterior Fixation System

Given that the RIVA Posterior Fixation System is a physical medical device (spinal implant and surgical instruments), the "acceptance criteria" and "study that proves the device meets the acceptance criteria" differ significantly from those for an AI/software device. For physical devices like this, acceptance is primarily based on meeting mechanical performance standards and demonstrating substantial equivalence to existing legally marketed predicate devices.

1. Table of Acceptance Criteria and Reported Device Performance

Acceptance Criteria Category	Specific Criteria (from document)	Reported Device Performance (from document)	Notes
Mechanical Performance	Adherence to ASTM F1717 standards	Demonstrated substantially equivalent mechanical performance in: - Static and dynamic compression bending - Static torsion - Axial and torsional grip - Tulip shank dissociation - Flexion-extension	These are industry-standard tests for spinal implants to ensure strength, durability, and resistance to common stresses. "Substantially equivalent" means the performance is comparable to and not worse than the predicate devices, not necessarily meeting a specific numerical threshold beyond that.
Mechanical Performance	Adherence to ASTM F1798 standards	Demonstrated substantially equivalent mechanical performance.	ASTM F1798 covers resistance to unscrewing for spinal implants.
Navigation Instrument Accuracy	Instruments register and function properly with Medtronic® StealthStation™ S8 System	Accuracy testing confirmed instruments register and function properly.	This implies that the instruments provide sufficiently accurate anatomical location data when used with the specified navigation system.
Navigation Instrument Dimensional Analysis	Dimensions are comparable to predicate instruments.	Dimensional analysis performed against predicate instruments.	This ensures compatibility and similar performance characteristics to established navigation instruments.
Biocompatibility	Use of Biocompatible Materials	Implants manufactured from titanium alloy (Ti-6Al-4V ELI per ASTM F136) and/or cobalt chrome alloy (Co-28Cr-6Mo per ASTM F1537 or Co-35Ni-20Cr-10Mo per ASTM F562).	These are well-established, biocompatible materials commonly used in medical implants, conforming to relevant ASTM standards. Although not explicitly stated as "acceptance criteria," material conformity is a fundamental requirement.
Sterilization	Compatibility with Steam Sterilization	Accessories include trays and caddies for storage, protection, and organization prior to and during the steam sterilization process.	Confirms the device/accessories are designed for appropriate sterilization.

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

Sample Size: The document does not specify the exact number of devices or components tested for mechanical or accuracy performance. For mechanical testing, samples typically involve multiple units of each component type (e.g., screws, rods, connectors) to ensure statistical validity across batches. For navigation instrument accuracy, it would involve a certain number of instrument uses with the navigation system.
Data Provenance: The data provenance is from laboratory testing (mechanical and accuracy testing) performed by the manufacturer, HT Medical d.b.a. Xenix Medical. This is not patient data; it's engineering test data.
- Country of Origin: Not specified, but generally performed at the manufacturer's R&D facilities or contracted testing labs, typically in the country of manufacture or where submission is being sought (implied US, given FDA 510(k)).
- Retrospective or Prospective: This is not applicable in the context of laboratory mechanical/accuracy testing.

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

This section is not applicable in the context of this device and submission type. "Ground truth" as defined for AI/software (e.g., expert consensus on medical images) is not relevant here. The "truth" is established by the physical and mechanical properties of the device and its ability to function as intended in a controlled laboratory environment according to established engineering standards (ASTM). The "experts" involved would be engineers, material scientists, and quality assurance personnel conducting the tests and interpreting the results against the ASTM standards.

4. Adjudication Method for the Test Set

This is not applicable. Adjudication methods (like 2+1, 3+1 consensus) are used for resolving disagreements in labeling or classifying data, typically by human experts reviewing complex medical images or clinical cases. For mechanical testing, the "adjudication" is against the pre-defined ASTM standards and the performance of the predicate device. Test results are quantitative and either meet or do not meet the criteria.

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 performed or described in this 510(k) submission. MRMC studies are typically done for diagnostic imaging devices or AI tools that assist human readers in making clinical decisions. This device is a surgical implant and navigation system, not a diagnostic tool requiring MRMC.

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

Not Applicable. This concept applies to AI algorithms. The "RIVA Posterior Fixation System" is a physical implant and surgical navigation instrumentation. There is no standalone "algorithm" to evaluate in this context. The navigation instruments are designed for "human-in-the-loop" use with a surgeon and the Medtronic StealthStation system.

7. The Type of Ground Truth Used

The "ground truth" for this device's performance assessment is based on accepted engineering standards (ASTM F1717, ASTM F1798) and the established performance of the predicate devices. This means:

Mechanical Integrity: The ability to withstand specified static and dynamic forces as defined by ASTM standards.
Functional Accuracy: For the navigation instruments, the ability to register and provide accurate location information within the Medtronic StealthStation system, demonstrated through bench testing.
Material Conformity: Conformance to specified biocompatible material standards.

It is not based on expert consensus, pathology, or outcomes data in the way an AI diagnostic tool would be validated. Clinical outcomes data would typically be gathered in post-market surveillance or specific clinical trials for PMA devices, which this is not.

8. The Sample Size for the Training Set

Not applicable. This device does not involve a "training set" in the context of machine learning. There is no algorithm being trained.

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

Not applicable. As there is no training set for an AI algorithm, there is no ground truth established for one. The "truth" for the design and manufacturing of this physical device is based on engineering principles, material science, and established manufacturing processes.

Summary Caveat:

It is crucial to understand that the provided document is a 510(k) clearance letter for a traditional physical medical device (implant and instruments). The questions in your prompt are specifically tailored towards the validation of Artificial Intelligence (AI) or software as a medical device (SaMD). Therefore, many of the requested details (like ground truth establishment from experts, MRMC studies, training/test sets for algorithms) are not relevant to this type of device and are consequently not found in the 510(k) clearance letter. The FDA's assessment for this device focuses on substantial equivalence in terms of intended use, indications for use, design, materials, function, manufacturing, and most importantly, mechanical performance as demonstrated through rigorous engineering bench testing.

Summary

FDA 510(k) Clearance Letter - RIVA Posterior Fixation System

Page 1

U.S. Food & Drug Administration
10903 New Hampshire Avenue
Silver Spring, MD 20993
www.fda.gov

Doc ID # 04017.07.05

June 12, 2025

HT Medical d.b.a. Xenix Medical
Tyler Holschlag
Vice President Product Development
111 W Jefferson St., Suite 100
Orlando, Florida 32801

Re: K251154
Trade/Device Name: RIVA Posterior Fixation System; RIVA Posterior Fixation System Navigation Instruments
Regulation Number: 21 CFR 888.3070
Regulation Name: Thoracolumbosacral Pedicle Screw System
Regulatory Class: Class II
Product Code: NKB, KWQ, OLO
Dated: April 8, 2025
Received: April 14, 2025

Dear Tyler Holschlag:

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.

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K251154 - Tyler Holschlag Page 2

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).

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 (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-reporting-combination-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.

All medical devices, including Class I and unclassified devices and combination product device constituent parts are required to be in compliance with the final Unique Device Identification System rule ("UDI Rule"). The UDI Rule requires, among other things, that a device bear a unique device identifier (UDI) on its label and package (21 CFR 801.20(a)) unless an exception or alternative applies (21 CFR 801.20(b)) and that the dates on the device label be formatted in accordance with 21 CFR 801.18. The UDI Rule (21 CFR 830.300(a) and 830.320(b)) also requires that certain information be submitted to the Global Unique Device Identification Database (GUDID) (21 CFR Part 830 Subpart E). For additional information on these requirements, please see the UDI System webpage at https://www.fda.gov/medical-devices/device-advice-comprehensive-regulatory-assistance/unique-device-identification-system-udi-system.

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-devices/medical-device-safety/medical-device-reporting-mdr-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/medical-devices/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-devices/device-advice-comprehensive-regulatory-

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K251154 - Tyler Holschlag Page 3

assistance/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,

EILEEN CADEL -S

for

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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DEPARTMENT OF HEALTH AND HUMAN SERVICES
Food and Drug Administration

Form Approved: OMB No. 0910-0120
Expiration Date: 07/31/2026
See PRA Statement below.

Indications for Use

510(k) Number (if known): K251154

Device Name: RIVA Posterior Fixation System; RIVA Posterior Fixation System Navigation Instruments

Indications for Use (Describe)

Degenerative disc disease (defined as discogenic back pain with degeneration of the disc confirmed by history and radiographic studies).
Spondylolisthesis
Trauma (i.e. fracture or dislocation).
Spinal Stenosis
Deformities or curvatures (i.e scoliosis, kyphosis, and/or lordosis)
Tumor
Pseudoarthrosis
Failed previous fusion

Xenix Medical fenestrated screws are intended to be used with saline or radiopaque dye.

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)

CONTINUE ON A SEPARATE PAGE IF NEEDED.

This section applies only to requirements of the Paperwork Reduction Act of 1995.

DO NOT SEND YOUR COMPLETED FORM TO THE PRA STAFF EMAIL ADDRESS BELOW.

The burden time for this collection of information is estimated to average 79 hours per response, including the time to review instructions, search existing data sources, gather and maintain the data needed and complete and review the collection of information. Send comments regarding this burden estimate or any other aspect of this information collection, including suggestions for reducing this burden, to:

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FORM FDA 3881 (8/23) K251154 Page 1 of 1 PSC Publishing Services (301) 443-6740 EF

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510(k) Summary

Device Trade Name: RIVA Posterior Fixation System

Manufacturer: HT Medical d.b.a Xenix Medical
111 W Jefferson St., Suite 100
Orlando, FL 32801

Contact: Tyler Holschlag
Vice President of Product Development
Xenix Medical

Date Prepared: June 12, 2025

Classifications: 21 CFR §888.3070; Thoracolumbosacral pedicle screw system
21 CFR §888.3060; Spinal intervertebral body fixation orthosis
21 CFR §882.4560; Stereotaxic Instruments

Class: II

Product Codes: NKB, KWQ, OLO

Indications for Use:

Degenerative disc disease (defined as discogenic back pain with degeneration of the disc confirmed by history and radiographic studies).
Spondylolisthesis
Trauma (i.e. fracture or dislocation).
Spinal Stenosis
Deformities or curvatures (i.e scoliosis, kyphosis, and/or lordosis)
Tumor
Pseudoarthrosis
Failed previous fusion

K251154 Page 1 of 3

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Xenix Medical RIVA Posterior Fixation System fenestrated screws are intended to be used with saline or radiopaque dye.

Device Description:

Predicate Devices:

Device Name(s)	Manufacture	K-Number
Primary Predicate
Primus Spinal Fixation System	Spinal Elements	K243916
Additional Predicate Devices
Atlas Spine Pedicle Screw System	Atlas Spine	K112759
Mariner Pedicle Screw System	SeaSpine	K212692
Medtronic CD Horizon	Medtronic	K140454

K251154 Page 2 of 3

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Performance Testing Summary:

The Xenix Medical RIVA Posterior Fixation System demonstrated substantially equivalent mechanical performance to the predicate devices through static and dynamic compression bending, static torsion, axial and torsional grip, tulip shank dissociation, and flexion-extension with reference to ASTM F1717 and ASTM F1798.

Accuracy testing was performed on the Xenix Medical RIVA Posterior Fixation System Navigation instruments to confirm that the instruments register and function properly with the Medtronic® StealthStation™ System. Dimensional analysis of the Xenix Medical RIVA Posterior Fixation System Navigation instruments was performed against the predicate instruments.

Substantial Equivalence:

The subject device was demonstrated to be substantially equivalent to the predicate cited in the passage above with respect to indications, design, materials, function, manufacturing, and performance.

Conclusion:

The Xenix Medical RIVA Posterior Fixation System is substantially equivalent to the cited predicate devices with respect to intended use, indications for use, design, function, materials, and performance. The differences in the technological characteristics between the subject device and the predicate devices do not raise new or different questions of safety and effectiveness.

K251154 Page 3 of 3

Regulation Number and Section

§ 888.3070 Thoracolumbosacral pedicle screw system.

(a)
Identification. (1) Rigid pedicle screw systems are comprised of multiple components, made from a variety of materials that allow the surgeon to build an implant system to fit the patient's anatomical and physiological requirements. Such a spinal implant assembly consists of a combination of screws, longitudinal members (e.g., plates, rods including dual diameter rods, plate/rod combinations), transverse or cross connectors, and interconnection mechanisms (e.g., rod-to-rod connectors, offset connectors).(2) Semi-rigid systems are defined as systems that contain one or more of the following features (including but not limited to): Non-uniform longitudinal elements, or features that allow more motion or flexibility compared to rigid systems.
(b)
Classification. (1) Class II (special controls), when intended to provide immobilization and stabilization of spinal segments in skeletally mature patients as an adjunct to fusion in the treatment of the following acute and chronic instabilities or deformities of the thoracic, lumbar, and sacral spine: severe spondylolisthesis (grades 3 and 4) of the L5-S1 vertebra; degenerative spondylolisthesis with objective evidence of neurologic impairment; fracture; dislocation; scoliosis; kyphosis; spinal tumor; and failed previous fusion (pseudarthrosis). These pedicle screw spinal systems must comply with the following special controls:(i) Compliance with material standards;
(ii) Compliance with mechanical testing standards;
(iii) Compliance with biocompatibility standards; and
(iv) Labeling that contains these two statements in addition to other appropriate labeling information:
“Warning: The safety and effectiveness of pedicle screw spinal systems have been established only for spinal conditions with significant mechanical instability or deformity requiring fusion with instrumentation. These conditions are significant mechanical instability or deformity of the thoracic, lumbar, and sacral spine secondary to severe spondylolisthesis (grades 3 and 4) of the L5-S1 vertebra, degenerative spondylolisthesis with objective evidence of neurologic impairment, fracture, dislocation, scoliosis, kyphosis, spinal tumor, and failed previous fusion (pseudarthrosis). The safety and effectiveness of these devices for any other conditions are unknown.”
“Precaution: The implantation of pedicle screw spinal systems should be performed only by experienced spinal surgeons with specific training in the use of this pedicle screw spinal system because this is a technically demanding procedure presenting a risk of serious injury to the patient.”
(2) Class II (special controls), when a rigid pedicle screw system is intended to provide immobilization and stabilization of spinal segments in the thoracic, lumbar, and sacral spine as an adjunct to fusion in the treatment of degenerative disc disease and spondylolisthesis other than either severe spondylolisthesis (grades 3 and 4) at L5-S1 or degenerative spondylolisthesis with objective evidence of neurologic impairment. These pedicle screw systems must comply with the following special controls:
(i) The design characteristics of the device, including engineering schematics, must ensure that the geometry and material composition are consistent with the intended use.
(ii) Non-clinical performance testing must demonstrate the mechanical function and durability of the implant.
(iii) Device components must be demonstrated to be biocompatible.
(iv) Validation testing must demonstrate the cleanliness and sterility of, or the ability to clean and sterilize, the device components and device-specific instruments.
(v) Labeling must include the following:
(A) A clear description of the technological features of the device including identification of device materials and the principles of device operation;
(B) Intended use and indications for use, including levels of fixation;
(C) Identification of magnetic resonance (MR) compatibility status;
(D) Cleaning and sterilization instructions for devices and instruments that are provided non-sterile to the end user; and
(E) Detailed instructions of each surgical step, including device removal.
(3) Class II (special controls), when a semi-rigid system is intended to provide immobilization and stabilization of spinal segments in the thoracic, lumbar, and sacral spine as an adjunct to fusion for any indication. In addition to complying with the special controls in paragraphs (b)(2)(i) through (v) of this section, these pedicle screw systems must comply with the following special controls:
(i) Demonstration that clinical performance characteristics of the device support the intended use of the product, including assessment of fusion compared to a clinically acceptable fusion rate.
(ii) Semi-rigid systems marketed prior to the effective date of this reclassification must submit an amendment to their previously cleared premarket notification (510(k)) demonstrating compliance with the special controls in paragraphs (b)(2)(i) through (v) and paragraph (b)(3)(i) of this section.