(114 days)
The TWIST-OFF™ SCREW is intended to be implanted for fixation of bone fractures or bone reconstructions.
The TWIST-OFF™ SCREW is a threaded Titanium bone fixation appliance intended to be implanted. It is composed of a self-tapping, selfcompressive screw and support as a single piece. These two components separate when the screw head comes in contact with the cortex. Screws come in lengths of 11,12,13 and 14 mm; the support does not vary in size.
This looks like a 510(k) premarket notification document for a medical device, specifically a bone fixation screw. These documents generally focus on demonstrating substantial equivalence to a predicate device rather than providing extensive clinical study data with detailed acceptance criteria and performance metrics in the way a clinical trial for a novel drug or a more complex AI-driven diagnostic device would.
Based on the provided text, there isn't a comprehensive "study" in the sense of a clinical trial with acceptance criteria for device performance against human experts or a specific disease outcome. Instead, the "Summary of Studies" section describes bench testing to assess the mechanical properties of the device.
Here's an attempt to answer your questions based solely on the provided text:
1. A table of acceptance criteria and the reported device performance
| Acceptance Criteria | Reported Device Performance |
|---|---|
| Resistance to torsion (per French Standard N° NF-F-90-414) | "found to have a resistance to torsion in compliance with the selected Standard." |
2. Sample sized used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)
- Sample Size for Test Set: Not specified. The document only mentions "Rupture torque of the TWIST-OFF™ SCREW was compared..." without detailing how many screws were tested.
- Data Provenance: The standard referenced is "French Standard N° NF-F-90-414." This suggests the testing was conducted to a French standard, likely at the manufacturer's facility or a certified lab. It is a prospective bench test, not clinical data from patients.
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)
- Number of Experts: Not applicable. The "ground truth" here is a mechanical standard (resistance to torsion), not an expert interpretation of a clinical finding.
- Qualifications of Experts: Not applicable.
4. Adjudication method (e.g. 2+1, 3+1, none) for the test set
- Adjudication Method: Not applicable. This was a mechanical test against a predefined standard.
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
- MRMC Study: No. This device is a bone fixation screw, not an AI-driven diagnostic tool that would involve human readers.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
- Standalone Performance: Not applicable. This is a physical medical device, not an algorithm. The "standalone" performance here relates to its mechanical integrity.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc)
- Type of Ground Truth: The ground truth for the mechanical testing was an engineering standard (French Standard N° NF-F-90-414 for resistance to torsion).
8. The sample size for the training set
- Sample Size for Training Set: Not applicable. There is no "training set" in the context of this device's demonstration of substantial equivalence. The device's design is based on engineering principles and comparison to predicate devices, not machine learning training.
9. How the ground truth for the training set was established
- How Ground Truth for Training Set was Established: Not applicable. No training set was used.
Important Note: The information provided in 510(k) summaries is often limited to what is deemed necessary to demonstrate substantial equivalence. For a device like a bone screw, extensive clinical trials focused on efficacy might be unnecessary if its design and intended use are similar to already approved predicate devices, and its mechanical properties meet established standards.
§ 888.3040 Smooth or threaded metallic bone fixation fastener.
(a)
Identification. A smooth or threaded metallic bone fixation fastener is a device intended to be implanted that consists of a stiff wire segment or rod made of alloys, such as cobalt-chromium-molybdenum and stainless steel, and that may be smooth on the outside, fully or partially threaded, straight or U-shaped; and may be either blunt pointed, sharp pointed, or have a formed, slotted head on the end. It may be used for fixation of bone fractures, for bone reconstructions, as a guide pin for insertion of other implants, or it may be implanted through the skin so that a pulling force (traction) may be applied to the skeletal system.(b)
Classification. Class II.