(54 days)
The Medyssey Co. Ltd., Zenius™ Spinal System, a posterior spinal fixation device, indicated for skeletally mature patients receiving fusion by autogenous bone graft with removal of the implants after the attainment of a solid fusion and is intended to provide immobilization and stabilization of spinal segments 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).
The Zenius "M Spinal System is a top-loading posterior spinal fixation system which consists of pedicle screws, rods, set screws, and a transverse (cross) linking mechanism. The Zenius ™ Spinal System implant components are fabricated from titanium alloy (Ti-6AI-4V ELI) that conforms to ASTM F 136. Various sizes of these implants are available. Specialized instruments made from surgical instrument grade stainless steel are available for the application and removal of the Zenius™ Spinal System implants.
Here's an analysis of the provided text regarding the acceptance criteria and study for the Zenius™ Spinal System.
It's important to note that this document is a 510(k) Special Premarket Notification for a modification to an existing device. This type of submission often relies heavily on proving substantial equivalence to the predicate device, rather than entirely new, extensive studies.
Acceptance Criteria and Device Performance for Zenius™ Spinal System (K103272)
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria Category | Specific Criteria | Reported Device Performance |
|---|---|---|
| Mechanical Performance | Static Compression Bending (ASTM F 1717-04) | The predicate device underwent this testing. The subject device (modified Zenius™ Spinal System) contains "dimensionally modified components (not worst case)" and therefore was "not subject to ASTM F 1717-04 additional testing." This implies the modification was minor enough not to negatively impact the predicate's established performance or it was shown through analysis not to compromise the predicate's performance. |
| Static Tension Bending (ASTM F 1717-04) | Same as above. | |
| Static Torsional Testing (ASTM F 1717-04) | Same as above. | |
| Dynamic Compression Bending (ASTM F 1717-04) | Same as above. | |
| Biocompatibility/Materials | Conformance to ASTM F 136 for Titanium Alloy (Ti-6AI-4V ELI) | The implant components are fabricated from titanium alloy (Ti-6AI-4V ELI) that conforms to ASTM F 136. |
| Quality System Conformance | Adherence to 21 CFR part 820, ISO 9001, ISO 13485 | The design and development process of the manufacturer (both subject and predicate system) conforms to 21 CFR part 820, ISO 9001, and ISO 13485 quality systems. |
| Substantial Equivalence (Overall) | Same indications for use, contraindications, warnings, precautions, principles of operation. | The Modified Zenius™ Spinal System is stated to be "substantially equivalent" to the currently marketed Zenius™ Spinal System (K093104). Both systems use the same universal housing, pre-assembled pedicle screw, set screw, and vertical rods. The principles of operation are the same, employing the same indications for use, contraindications for use, warnings, and precautions within labeling. The design and development processes conform to relevant quality standards. The subject device "contains dimensionally modified components (not worst case)" and was therefore not subject to additional mechanical testing under ASTM F 1717-04 because the predicate device had already undergone such testing. No clinical tests were conducted on either the subject or predicate system. |
Regarding the Absence of Specific Information for AI-Related Questions:
It is crucial to understand that the provided text is for a spinal fixation system (a physical medical device), not an AI/software-as-a-medical-device (SaMD). Therefore, many of the questions related to AI performance, sample sizes for test/training sets, experts for ground truth, adjudication methods, and MRMC studies are not applicable to this type of device submission. The study is mechanical/physical testing, not an algorithmic performance evaluation.
2. Sample size used for the test set and the data provenance:
- Test Set Sample Size: Not explicitly stated as a numerical sample size in the context of device testing. Mechanical tests specified by ASTM F 1717-04 would involve a certain number of test units, but this detail is not provided.
- Data Provenance: The mechanical testing was performed by Medyssey Co., Ltd., which is a Korean company (Gyeonggi-do, Korea). The ASTM standards are international standards. This is lab-based physical testing, not a clinical data set.
- Retrospective/Prospective: Neither. This refers to laboratory mechanical testing, not clinical studies.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- Not Applicable. For a mechanical spinal implant, "ground truth" is established through engineering specifications, material properties, and adherence to validated testing standards (like ASTM F 1717-04). It does not involve expert consensus in the way an AI diagnostic tool would.
4. Adjudication method (e.g., 2+1, 3+1, none) for the test set:
- Not Applicable. Since there's no diagnostic or interpretative output from the device being evaluated by human experts, there's no adjudication method in play.
5. 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:
- Not Applicable. This is a hardware device; AI assistance for human readers is irrelevant.
6. If a standalone (i.e., algorithm only without human-in-the-loop performance) was done:
- Not Applicable. This is a physical implant, not an algorithm.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.):
- Engineering Specifications and Standardized Mechanical Test Results: The "ground truth" for this device revolves around its ability to meet the defined mechanical performance thresholds and material specifications outlined in standards like ASTM F 1717-04 and ASTM F 136. The predicate device's existing clearance (K093104) serves as the basis for substantial equivalence for similar material and design modifications.
8. The sample size for the training set:
- Not Applicable. This is not an AI device that requires a training set. The "training" for a physical device involves its design, manufacturing processes, and material selection, all adhering to established quality systems.
9. How the ground truth for the training set was established:
- Not Applicable. No training set in the AI sense. The "ground truth" for the device's design and manufacturing is established through adherence to engineering principles, material science, and quality management systems (21 CFR part 820, ISO 9001, ISO 13485).
§ 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.