(24 days)
The TOWNLEY Pedicle Screw Plating System is intended to stabilize the spine as an aid to fusion. After first making drill holes in the pedicles, a DYNA-LOK® plate is positioned of the pedicles. TOWNLEY Pedicle screws are then inserted through the DYNA-LOK® plate, down the center of the pedicles, and into the vertebral body. Bone graft must be used with each procedure.
This system is indicated for the treatment of any or all of the following at the C2 to S1 (inclusive) spinal levels: (a) Trauma, including spinal fractures and/or dislocations; (b) Spondylolisthesis; (c) Spondylolysis; (d) Pseudarthrosis or failed previous fusions which are symptomatic or which may cause secondary instability or deformity; (e) Degenerative disc disease and/or degenerative diseases which include: (1) degenerative disc disease (DDD) as defined by neck and/or back pain of discogenic origin as confirmed by radiographic studies; and/or (2) degenerative disease of the facets with instability.
This system consists of a broad-headed, partially threaded screw designed to compress bone grafts. Screw lengths range from 0.5 to 2.5 inches. Both cortical and cancellous screw threads are available. The screw comes in two configurations: flat-head or hex. The hex screws are slightly wider in diameter. The stainless steel DYNA-LOK® plates are used to interconnect two or more vertebrae together via screw fixation through the pedicles. All components are fabricated from medical grade stainless steel (ASTM F-138 or its ISO equivalent).
This document is a 510(k) summary for the TOWNLEY Pedicle Screw Plating System. It focuses on demonstrating substantial equivalence to a predicate device rather than presenting a study proving the device meets specific acceptance criteria in the way a clinical trial for a new drug or an AI-powered diagnostic device would.
Therefore, the requested information components related to an AI/diagnostic device study (such as sample size for test sets, data provenance, number of experts for ground truth, adjudication methods, MRMC studies, standalone performance, training set details) are not applicable to this type of regulatory submission.
The "acceptance criteria" here are essentially the demonstration of "substantial equivalence" to a legally marketed predicate device, as required for a 510(k) clearance by the FDA. The "study" proving it meets these criteria is the provided documentation itself, which asserts its similarity.
Here's a breakdown of what can be extracted from the provided text, aligned as much as possible with your request, but highlighting the inapplicability of many points:
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria (Demonstrated for 510(k) Substantial Equivalence) | Reported Device Performance/Characteristics |
|---|---|
| Product Description: | TOWNLEY Pedicle Screw Plating System: |
| - Screw design | - Broad-headed, partially threaded screw designed to compress bone grafts. |
| - Screw lengths | - 0.5 to 2.5 inches. |
| - Screw thread types | - Both cortical and cancellous screw threads available. |
| - Screw configurations | - Flat-head or hex (hex screws slightly wider in diameter). |
| - Plate usage | - Stainless steel DYNA-LOK® plates used to interconnect two or more vertebrae via screw fixation through pedicles. |
| - Materials | - All components fabricated from medical grade stainless steel (ASTM F-138 or its ISO equivalent). |
| Indications for Use: | Intended to stabilize the spine as an aid to fusion (with bone graft). Indicated for C2 to S1 levels for: |
| - Trauma | - Trauma, including spinal fractures and/or dislocations. |
| - Spondylolisthesis | - Spondylolisthesis. |
| - Spondylolysis | - Spondylolysis. |
| - Pseudarthrosis/Failed fusions | - Pseudarthrosis or failed previous fusions which are symptomatic or which may cause secondary instability or deformity. |
| - Degenerative disc disease (DDD) | - Degenerative disc disease (DDD) as defined by neck and/or back pain of discogenic origin as confirmed by radiographic studies. (Note: FDA letter clarifies this to require patient history and radiographic studies). |
| - Degenerative facet disease | - Degenerative disease of the facets with instability. |
| Performance Data/Comparison: | The document states "Documentation was provided which demonstrated the TOWNLEY Pedicle Screw Plating System was demonstrated to be substantially equivalent to itself." This implies comparison to a previously cleared version of the same device or a very similar predicate. No specific performance metrics are provided in the way a clinical study would. The FDA letter confirms the device is "substantially equivalent" for the specified indications when following the general controls and specific warnings/limitations. |
| Material Equivalence | All components fabricated from medical grade stainless steel (ASTM F-138 or its ISO equivalent), which is a common and accepted material for such implants. |
| Labeling Requirements | The FDA's acceptance includes specific labeling requirements, warnings, and limitations regarding pedicle screw fixation indications to ensure safe use and compliance. |
2. Sample size used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)
- Not applicable. This document describes a 510(k) submission, which relies on demonstrating substantial equivalence to a predicate device, not primary clinical performance data from a test set. There is no mention of a "test set" in the context of device performance data.
3. 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. No such test set or ground truth establishment by experts is described for this type of regulatory submission. The "ground truth" for a 510(k) is typically the established safety and effectiveness of the legally marketed predicate device.
4. Adjudication method (e.g. 2+1, 3+1, none) for the test set
- Not applicable. No test set or adjudication process is mentioned.
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 device is a mechanical implant, not an AI-powered diagnostic tool, and therefore MRMC studies are irrelevant.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
- Not applicable. This device is a mechanical implant, not an algorithm.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.)
- Not applicable. For a 510(k) of this nature, the "ground truth" is typically the regulatory acceptance of the predicate device based on its known characteristics, indications, and safety/effectiveness profile, which has already been established through prior regulatory processes (potentially including clinical data or consensus standards). The submission argues the new device is sufficiently similar to that predicate.
8. The sample size for the training set
- Not applicable. This device is a mechanical implant, not an AI model requiring a training set.
9. How the ground truth for the training set was established
- Not applicable. This device is a mechanical implant, not an AI model, and therefore has no training set or associated ground truth establishment.
In summary, the provided document is a 510(k) premarket notification, a regulatory pathway for medical devices that are substantially equivalent to already legally marketed devices. It does not contain information on clinical studies or performance data in the way a submission for a novel diagnostic or AI device would. The "study" demonstrating criteria fulfillment is the comparison and argument for substantial equivalence to a predicate device.
§ 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.