(70 days)
The VERTEX® Reconstruction System is intended to provide immobilization of spinal segments as an adjunct to fusion for the following acute and chronic instabilities of the craniocervical junction, the cervical spine (C1 to C7) and the thoracic spine from T1-T3: traumatic spinal fractures and/or traumatic dislocations; instability or deformity; failed previous fusions (e.g., pseudarthrosis); tumors involving the cervical spine; and degenerative disease, including intractable radiculopathy and/or myelopathy, neck and/or arm pain of discogenic origin as confirmed by radiographic studies, and degenerative diseaseof the facets with instability. The VERTEX® Reconstruction System is also intended to restore the integrity of the spinal column even in the absence of fusion for a limited time period in patients with advanced stage tumors involving the cervical spine in whom life expectancy is of insufficient duration to permit achievement of fusion.
In order to achieve additional levels of fixation, the VERTEX® Reconstruction System may be connected to the CD HORIZON® Spinal System rods with the VERTEX® rod connectors. Transition rods with differing diameters may also be used to connect the VERTEX® Reconstruction System to the CD HORIZON® Spinal System. Refer to the CD HORIZON® Spinal System package insert for a list of the CD HORIZON® Spinal System indications of use
The VERTEX® Reconstruction System is a posterior system which consists of a variety of shapes and sizes of plates, rods, hooks, screws, multi-axial screws, and connecting components, which can be rigidly locked to the rod in a variety of configurations. Conditions of the cervical spine, such as degenerative disc disease, tumor, or trauma, can lead to instability and pain for patients. In order to treat the instability, surgeons may need to use implants to reconstruct the spine. The VERTEX® Reconstruction System is a comprehensive set of options that provides adjustability, flexibility, and adaptability to meet the anatomical challenges of the occipitocervical and upper thoracic spine. The VERTEX® Reconstruction System is intended to be implanted by an orthopedic surgeon as described in the Surgical Technique. Each construct is specifically designed for each individual case. The components of the VERTEX® Reconstruction System are fabricated from medical grades of commercially pure titanium (ASTM F67-13), titanium alloy (ASTM F136-13), and cobalt chromium (ASTM F1537-11). The VERTEX® Reconstruction System also includes a retaining ring for the use with the multi-axial screw which is fabricated from Shape Memory Alloy, Nitinol-NiTi (ASTM F2063-12).
The sole purpose for this submission is to update the labeling for the VERTEX® Reconstruction System to include MRI safety information while also providing MRI technologists with a method of concluding whether an MRI scan can be performed and specific instructions on how to perform the scan.
This document describes the MRI safety evaluation of the VERTEX® Reconstruction System. It does not describe an AI medical device. Therefore, it's not possible to provide acceptance criteria and study details as they would apply to an AI device.
However, I can extract the information related to the MRI safety evaluation which is the focus of this submission. This is not an AI device, so many of the requested fields (like number of experts, adjudication methods, multi-reader studies, training sets) are not applicable.
Here's a summary of the MRI safety evaluation details:
Overall Purpose of Submission: To update the labeling for the VERTEX® Reconstruction System to include MRI safety information and instructions on how to perform an MRI scan with the device.
1. Table of Acceptance Criteria and Reported Device Performance (for MRI Safety)
| Acceptance Criteria Category | Standard/Requirement | Reported Device Performance (Summary) |
|---|---|---|
| Magnetically Induced Displacement Force | ASTM F2052:2014 | The device was evaluated for magnetically induced displacement force. The submission concludes that the device is MR-conditional after these evaluations. |
| Magnetically Induced Torque | ASTM F2213:2006 (2011) | The device was evaluated for magnetically induced torque. The submission concludes that the device is MR-conditional after these evaluations. |
| MR Image Artifacts | ASTM F2119:2007 (2013) | The device was evaluated for MR image artifacts. The submission concludes that the device is MR-conditional after these evaluations. |
| Radio Frequency (RF) Induced Heating | ASTM F2182:2002a, 2011, 2011a | A comprehensive computer simulation study was undertaken to identify "worst-case configurations" for heating, given the complexity of possible device configurations. These worst-case configurations were then physically tested in real MR scanners (both 1.5 T and 3 T) to measure actual heating. Heating generally decreased with increasing complexity of the constructs. The submission concludes that the device is MR-conditional after these evaluations. |
| Labeling Standard | ASTM F2503-13 "Standard Practice for Marking Medical Devices and Other Items for Safety in the Magnetic Resonance Environment" | The VERTEX® Reconstruction System has been labeled in accordance with this standard. |
Conclusion from all evaluations: The VERTEX® Reconstruction System was determined to be MR-conditional.
2. Sample Size Used for the Test Set and Data Provenance:
- A comprehensive computer simulation study was used to identify worst-case configurations for RF-induced heating. The document doesn't specify a "sample size" in terms of number of different construct models but states it involved "evaluating simple models (rods, screws, hooks) and adding additional components to create a more complex model."
- "Worst-case configurations" identified from simulations were physically tested in real MR scanners (both 1.5 T and 3 T). The specific number of constructs or tests conducted is not explicitly stated as a "sample size" but implies sufficient testing to cover critical configurations.
- The provenance is from Medtronic Sofamor Danek USA, Inc.'s internal testing and simulation studies, as described in their 510(k) submission. This is a prospective evaluation for the purpose of regulatory clearance.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications:
- This is not applicable as the study involves engineering and physics testing against established ASTM standards for MRI safety, not interpretation of medical images or clinical outcomes by experts.
4. Adjudication Method for the Test Set:
- Not applicable for this type of engineering and physics testing. Compliance is determined by meeting the specified limits and methodologies of the ASTM standards.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study:
- No, this is not an AI device or a diagnostic imaging aid. Therefore, no MRMC study was conducted.
6. Standalone (Algorithm Only Without Human-in-the-Loop Performance) Study:
- Not applicable, as this is a medical implant and its MRI safety evaluation, not a standalone algorithm. The "computer simulation study" aspect is a part of the engineering design and testing, not an AI algorithm.
7. The Type of Ground Truth Used:
- The "ground truth" here is the established physical principles and safety limits defined by international ASTM standards regarding MRI compatibility (e.g., maximum temperature rise, acceptable displacement force, torque, and artifact levels). The physical testing confirms adherence to these standards.
8. The Sample Size for the Training Set:
- Not applicable. There is no "training set" as this is not a machine learning or AI algorithm. The computer simulations are for identifying test configurations, not for training a model.
9. How the Ground Truth for the Training Set Was Established:
- Not applicable as there is no training set for an AI model.
§ 888.3075 Posterior cervical screw system.
(a)
Identification. Posterior cervical screw systems are comprised of multiple, interconnecting components, made from a variety of materials that allow an implant system to be built from the occiput to the upper thoracic spine to fit the patient's anatomical and physiological requirements, as determined by preoperative cross-sectional imaging. Such a spinal assembly consists of a combination of bone anchors via screws (i.e., occipital screws, cervical lateral mass screws, cervical pedicle screws, C2 pars screws, C2 translaminar screws, C2 transarticular screws), longitudinal members (e.g., plates, rods, including dual diameter rods, plate/rod combinations), transverse or cross connectors, interconnection mechanisms (e.g., rod-to-rod connectors, offset connectors), and closure mechanisms (e.g., set screws, nuts). Posterior cervical screw systems are rigidly fixed devices that do not contain dynamic features, including but not limited to: non-uniform longitudinal elements or features that allow more motion or flexibility compared to rigid systems.Posterior cervical screw systems are intended to provide immobilization and stabilization of spinal segments in patients as an adjunct to fusion for acute and chronic instabilities of the cervical spine and/or craniocervical junction and/or cervicothoracic junction such as: (1) Traumatic spinal fractures and/or traumatic dislocations; (2) deformities; (3) instabilities; (4) failed previous fusions (
e.g., pseudarthrosis); (5) tumors; (6) inflammatory disorders; (7) spinal degeneration, including neck and/or arm pain of discogenic origin as confirmed by imaging studies (radiographs, CT, MRI); (8) degeneration of the facets with instability; and (9) reconstruction following decompression to treat radiculopathy and/or myelopathy. These systems are also intended to restore the integrity of the spinal column even in the absence of fusion for a limited time period in patients with advanced stage tumors involving the cervical spine in whom life expectancy is of insufficient duration to permit achievement of fusion.(b)
Classification. Class II (special controls). The special controls for posterior cervical screw systems are:(1) The design characteristics of the device, including engineering schematics, must ensure that the geometry and material composition are consistent with the intended use.
(2) Nonclinical performance testing must demonstrate the mechanical function and durability of the implant.
(3) Device components must be demonstrated to be biocompatible.
(4) Validation testing must demonstrate the cleanliness and sterility of, or the ability to clean and sterilize, the device components and device-specific instruments.
(5) Labeling must include the following:
(i) A clear description of the technological features of the device including identification of device materials and the principles of device operation;
(ii) Intended use and indications for use including levels of fixation;
(iii) Device specific warnings, precautions, and contraindications that include the following statements:
(A) “Precaution: Preoperative planning prior to implantation of posterior cervical screw systems should include review of cross-sectional imaging studies (
e.g., CT and/or MRI) to evaluate the patient's cervical anatomy including the transverse foramen, neurologic structures, and the course of the vertebral arteries. If any findings would compromise the placement of these screws, other surgical methods should be considered. In addition, use of intraoperative imaging should be considered to guide and/or verify device placement, as necessary.”(B) “Precaution: Use of posterior cervical pedicle screw fixation at the C3 through C6 spinal levels requires careful consideration and planning beyond that required for lateral mass screws placed at these spinal levels, given the proximity of the vertebral arteries and neurologic structures in relation to the cervical pedicles at these levels.”
(iv) Identification of magnetic resonance (MR) compatibility status;
(v) Cleaning and sterilization instructions for devices and instruments that are provided non-sterile to the end user, and;
(vi) Detailed instructions of each surgical step, including device removal.