(30 days)
The MX Polvaxial Pedicle Screw is a pedicle screw system 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: degenerative spondylolisthesis with objective evidence of neurological impairment, fracture, dislocation, scoliosis, kyphosis, spinal tumor, and failed previous fusion (pseudarthrosis).
As a pedicle screw system the MX Polyaxial Pedicle Screws are indicated for the treatment of severe spondylolisthesis (Grades 3 and 4) of the L5-S1 vertebra in skeletally mature patients receiving fusion by autogenous bone graft having implants attached to the lumbar and sacral spine (L3 to sacrum) with removal of the implants after the attainment of a solid fusion.
The MX Polyaxial Pedicle Screw consists of pedicle screws and rods. Pedicle screws are inserted into the pedicles of the vertebrae and are available in three diameters (Ø6.2, Ø7.0 and Ø8.0mm) and in lengths ranging from 35mm to 70mm. A rod is then inserted through an opening in the side of the head of the screw. A set screw is inserted through the top of the screw head. As the set screw is tightened the rod is secured in the screw head and the polyaxial mechanism is fixed in place. The rods are available in lengths ranging from 45-600mm.
The MX is fabricated from material that conforms to ASTM F136 (Ti-6Al-4V alloy).
The provided 510(k) summary for the MX Polyaxial Pedicle Screw describes a medical device, but it does not contain information about acceptance criteria or a study proving device performance in the context of clinical or diagnostic efficacy, which is typically the focus of such questions.
Instead, the document details:
- Device Description: What the device is made of and how it functions mechanically.
- Intended Use: The medical conditions and patient population for which the device is designed.
- Summary of Nonclinical Tests: This explicitly states "Testing was performed per ASTM F1717." ASTM F1717 is a standard for mechanical testing of spinal implants, specifically for spinal implant constructs in a dynamic compression testing environment. This type of testing assesses the structural integrity, fatigue life, and mechanical properties of the device itself, not its clinical performance in patients or a comparison against a diagnostic standard.
Therefore, many of the requested details, such as sample size for test sets, data provenance, expert qualifications, ground truth establishment for a diagnostic study, MRMC studies, or standalone algorithm performance, are not applicable and not present in this document.
Here’s a description of the acceptance criteria and the study as much as can be extracted from the provided text, focusing on the mechanical testing aspect:
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria Category | Specific Acceptance Criteria (Inferred from ASTM F1717) | Reported Device Performance |
|---|---|---|
| Mechanical Performance | Conformance to ASTM F1717 (e.g., fatigue strength, static compression, torsion properties, construct stability) | Testing was performed per ASTM F1717. |
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size for Test Set: Not specified in the document. For mechanical testing per ASTM F1717, the sample size would refer to the number of device constructs tested, not human patient data.
- Data Provenance: Not applicable in the context of clinical or diagnostic data. For mechanical testing, the data would be generated in a laboratory setting.
- Retrospective or Prospective: Not applicable as this relates to clinical studies.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications
- Not applicable. For mechanical testing, ground truth is established by applying the test standard (ASTM F1717) and measuring physical properties, not by expert consensus on clinical findings.
4. Adjudication Method for the Test Set
- Not applicable. Adjudication relates to resolving discrepancies in expert interpretations of clinical data.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done
- No. This type of study assesses human reader performance, often with and without AI assistance, for diagnostic tasks. The provided document concerns mechanical performance of a spinal implant.
6. If a Standalone (Algorithm Only Without Human-in-the-Loop Performance) Was Done
- No. Standalone performance usually refers to the accuracy of an AI algorithm on its own. This document describes a physical medical device.
7. The Type of Ground Truth Used
- Mechanical Test Standards and Measurements: For the "Summary of Nonclinical Tests," the ground truth is adherence to the specifications and performance requirements outlined in ASTM F1717. This standard provides methodologies and criteria for evaluating the mechanical properties of spinal implant constructs. The device's performance is measured against these established engineering and biomechanical benchmarks.
8. The Sample Size for the Training Set
- Not applicable. Training sets are used for machine learning algorithms. The device is a physical pedicle screw system.
9. How the Ground Truth for the Training Set Was Established
- Not applicable.
In summary, the provided text focuses on the mechanical and material safety/performance of the MX Polyaxial Pedicle Screw, demonstrating its substantial equivalence to predicate devices through compliance with ASTM F1717. It does not contain information related to clinical efficacy studies, diagnostic performance, or AI/software analysis that would involve human subjects, expert review, or machine learning methodologies.
§ 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.