(54 days)
The PMT Posterior Fixation System is intended to provide immobilization of spinal segments as an adjunct to fusion for the following acute and chronic instabilities of the cervical spine (C1 to C7) and the thoracic spine from T1 to 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 disease of the facets with instability.
The PMT Posterior Fixation 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.
The PMT Posterior Fixation System is a bone screw and rod construct that will be supplied sterile and single use only. It consists of polyaxial screws, fixation rods, and locking set screws. The polyaxial screws are designed to be utilized for pedicle fixation or anchored to the posterior lateral mass of the cervical (C1 to C7) and thoracic (T1 to T3) vertebra. A set screw is used to connect and anchor the rod to each screw head while locking the orientation of the polyaxial screw.
The PMT Posterior Fixation System is manufactured from 6Al-4V Titanium Alloy, conforming to ASTM F136. The polyaxial screw, available in diameters of 3.5mm and 4.0mm, is self-tapping with a range of screw lengths between 8mm to 24mm. The rod is offered in two diameters, 3.5mm and 3.8mm, with a range in lengths of 15mm to 240mm. The screw head that is assembled to the polyaxial screw accepts the 3.5mm or 3.8mm rod. The set screw comes in one size and has a matching thread profile to the screw head.
The provided text describes a 510(k) premarket notification for a medical device called the "PMT Posterior Fixation System." This document is a regulatory submission to the FDA, demonstrating that the new device is "substantially equivalent" to an existing legally marketed predicate device.
Crucially, this document focuses on demonstrating substantial equivalence of a physical medical implant, not an AI/software device that requires performance metrics against acceptance criteria related to accuracy, sensitivity, specificity, etc.
Therefore, most of the requested information regarding acceptance criteria for AI performance, sample sizes for test/training sets, ground truth establishment, expert adjudication, or MRMC studies is not applicable to this document. The "performance testing" referenced is for the physical properties of the implant (e.g., static compression bending, static torsion, dynamic compression bending) as per ASTM F1717, to demonstrate its mechanical equivalence to the predicate device.
Here's an attempt to answer the questions based on the provided text, while highlighting what is not applicable:
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A table of acceptance criteria and the reported device performance
- Not Applicable in the AI/Software context: This document does not describe acceptance criteria for an AI algorithm's performance (e.g., sensitivity, specificity, AUC).
- Applicable in the medical device context (physical attributes): The acceptance criteria are implicitly that the PMT Posterior Fixation System performs equivalently or better than the predicate device in biomechanical tests as per ASTM F1717.
| Acceptance Criteria (Implied) | Reported Device Performance |
| :---------------------------- | :-------------------------- |
| Substantial equivalence to predicate device in mechanical performance (static compression bending, static torsion, dynamic compression bending) as per ASTM F1717. | "Non-clinical testing conducted per ASTM F1717 (static compression bending, static torsion, and dynamic compression bending) has demonstrated that the PMT Posterior Fixation System is substantially equivalent to the predicate device." |
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Sample sizes used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)
- Not Applicable in the AI/Software context: There is no "test set" of patient data for AI performance evaluation.
- Applicable in the medical device context (physical attributes): This refers to the number of physical devices or components tested. The document does not specify the sample size for the mechanical testing, only that testing was conducted per ASTM F1717. Data provenance (country of origin, retrospective/prospective) is not relevant for this type of mechanical testing.
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Number of experts used to establish the ground truth for the test set and the qualifications of those experts (e.g. radiologist with 10 years of experience)
- Not Applicable: This pertains to establishing ground truth for AI model evaluation. The document describes a physical medical device; no "ground truth" based on expert interpretation of medical images or data is established here. Mechanical performance is measured through standardized ASTM tests.
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Adjudication method (e.g. 2+1, 3+1, none) for the test set
- Not Applicable: Adjudication is relevant for resolving discrepancies in expert interpretations for establishing ground truth in AI studies. This is not a study of AI performance.
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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 study design for evaluating AI assistance to human readers. The document is for a physical medical implant, not an AI diagnostic or assistive tool.
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If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
- Not Applicable: There is no algorithm being evaluated in this submission.
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The type of ground truth used (expert concensus, pathology, outcomes data, etc)
- Not Applicable for AI/Software ground truth: The concept of "ground truth" as used in AI performance evaluation (e.g., for disease detection in images) does not apply here.
- Ground truth (for mechanical testing): The "ground truth" for the mechanical performance of this physical device is established by the specifications and standardized testing methods defined in ASTM F1717. The predicate device's performance also serves as a benchmark for "equivalence."
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The sample size for the training set
- Not Applicable: This is relevant for AI model development. There is no training set mentioned for this physical device.
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How the ground truth for the training set was established
- Not Applicable: As there is no training set for an AI model, this question is not relevant.
§ 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.