(84 days)
The intended use of the Virata Spinal Fixation System in a posterior or anterolateral approach is 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.
The indications for use are as follows:
- degenerative disc disease (DDD) as defined by back pain of discogenic origin with degeneration of the disc confirmed by patient history and radiographic studies,
- spondylolisthesis,
- trauma (i.e., fracture or dislocation),
- spinal stenosis,
- deformities or curvatures (i.e., scoliosis, kyphosis, and/or lordosis),
- spinal tumor,
- pseudarthrosis, and/or
- failed previous fusion.
When used for posterior non-cervical screw fixation in pediatric patients, the Virata Spinal Fixation System is also indicated as adjunct to fusion to treat:
- Adolescent Idiopathic Scoliosis (AIS)
- Neuromuscular scoliosis
- Congenital scoliosis
The Virata Spinal Fixation System can be used with components of the Mariner and Malibu Systems such as rods and connectors. The Virata Spinal Fixation System is intended to be used with autograft or allograft.
Virata Spinal Fixation Navigated Instruments:
The Virata Spinal Fixation Navigated Instruments are intended to be used in the preparation and placement of Virata screws during spinal 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® System, which is indicated for any medical condition in which the use of stereotactic surgery may be appropriate, and where reference to a rigid anatomical structure, such as a vertebra, can be identified relative to a CT or MR based model, fluoroscopy images, or digitized landmarks of the anatomy.
The Virata Spinal Fixation System is a pedicle screw-based system that utilizes modular and preassembled screws. The modular screw shanks and the shanks of the preassembled screws are available in solid and cannulated configurations, in a variety of length and diameter size options. The rods are provided in a variety of lengths, diameters, and material options in both straight and pre-contoured configurations that can also be bent with instrumentation to more optimally accommodate the anatomy.
The Virata Spinal Fixation System consists of single-use implants intended to build constructs within the body to act as a temporary or permanent posterior, non-cervical pedicle fixation system, or an anterolateral fixation system to correct spinal disorders and provide stabilization of the spine to permit the biological process of spinal fusions to occur.
Screws are placed in the pedicles of the vertebral body using a posterior approach. The construct is connected using rods to span across screws implanted at various levels. The construct is secured using a set screw tightened to a predetermined torque value which is threaded into the top of the screw to secure the rod. All modular tulips and the tulips of preassembled screws of the system are designed to accept a rod through the opening in the top of the tulip, except the closed polyaxial modular tulip and the tulip of closed preassembled screws for which the rod is passed through an opening on the side of the tulip. The Virata Spinal Fixation System implants are manufactured from titanium alloy Ti-6Al-4V ELI (per ASTM F136), and cobalt chrome alloy (Co-28Cr-6Mo per ASTM F1537).
The system includes the associated non-sterile instruments that facilitate the placement, adjustment, and removal, if necessary, of the system implants as well as trays and caddies that may be used for storage, protection, and organization prior to and during the steam sterilization process for the non-sterile components. Non-sterile instruments also include instrumentation compatible with navigation arrays to allow for navigated implant placement.
The provided document, an FDA 510(k) clearance letter for the Virata Spinal Fixation System, is for a medical device (spinal implant) and not an AI/software-as-a-medical-device (SaMD). Therefore, the information typically required for describing acceptance criteria and a study proving a digital device meets those criteria (such as analysis of test sets, ground truth establishment, expert adjudication, MRMC studies, standalone performance, and training data) is not applicable or present in this document.
Instead, the document focuses on the mechanical performance and substantial equivalence of the physical spinal fixation system to existing predicate devices.
Here's the relevant information that can be extracted from the provided text, adapted to the context of a physical medical device:
1. Table of Acceptance Criteria and Reported Device Performance
For the Virata Spinal Fixation System, acceptance criteria are generally implied by demonstrating safe and effective mechanical performance as compared to predicate devices, typically by meeting or exceeding standards outlined in ASTM (American Society for Testing and Materials) standards. The document doesn't explicitly list numerical acceptance criteria values or specific reported device performance metrics beyond stating that testing was conducted and the device was found substantially equivalent.
However, the types of tests performed indicate the areas where mechanical performance was evaluated:
| Acceptance Criteria Area (Implied by Test Type) | Reported Device Performance |
|---|---|
| Dynamic Compression Bending (ASTM F1717) | Results demonstrate substantial equivalence to legally marketed devices. |
| Static Compression Bending (ASTM F1717) | Results demonstrate substantial equivalence to legally marketed devices. |
| Static Torsion (ASTM F1717) | Results demonstrate substantial equivalence to legally marketed devices. |
| Static Anterior-Posterior Load (Fx) (ASTM F1798) | Results demonstrate substantial equivalence to legally marketed devices. |
| Static Anterior-Posterior Load (Fx) at Max-Angle (ASTM F1798) | Results demonstrate substantial equivalence to legally marketed devices. |
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size: The document does not specify the exact number of test samples (e.g., screws, rods, constructs) used for each mechanical test. Mechanical testing typically involves a sufficient number of samples to ensure statistical validity for the properties being evaluated, as per the ASTM standards.
- Data Provenance: Not applicable in the context of mechanical testing of a physical implant. The "test set" here refers to the physical devices manufactured for testing. The testing was conducted by SeaSpine Orthopedics Corporation as part of their 510(k) submission.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
Not applicable. For mechanical testing of a physical device, "ground truth" is established by the physical properties and performance characteristics measured according to standardized test methods (e.g., ASTM standards), not by human expert opinion or interpretation in the way it is for digital health technologies.
4. Adjudication Method for the Test Set
Not applicable. Adjudication methods like "2+1" or "3+1" are relevant for reconciling differing expert opinions in clinical or diagnostic assessments, not for objective mechanical performance tests.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was Done
No. An MRMC study is relevant for evaluating the impact of an assist device (like AI) on human diagnostic performance. The Virata Spinal Fixation System is a physical implant, not a diagnostic or AI-assisted device. While it includes "Navigated Instruments," these are physical tools designed for use with a separate "Medtronic StealthStation® System" (a stereotactic surgery system), and the testing presented here focuses on the mechanical performance of the fixation system itself, not a comparative effectiveness study involving human readers' diagnostic accuracy.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was Done
Not applicable. This is not an algorithm or software device.
7. The Type of Ground Truth Used
For the mechanical performance testing, the "ground truth" is defined by the objective physical measurements and adherence to the specified performance parameters and failure modes outlined within the respective ASTM standards (F1717 and F1798). Compatibility and substantial equivalence to existing predicate devices (SeaSpine Mariner Pedicle Screw System, NuVasive GSB Global Spinal Balance System) also serve as a form of "ground truth" benchmark.
8. The Sample Size for the Training Set
Not applicable. There is no "training set" in the context of mechanical testing for a physical implant.
9. How the Ground Truth for the Training Set was Established
Not applicable. There is no "training set" or "ground truth" establishment in this context.
§ 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.