(12 days)
BELL VARIO: Partial ossicle replacement in case of interrupted sound conducting chain and intact mobile stapes.
AERIAL VARIO: Total ossicle replacement in case of interrupted sound conducting chain and intact mobile stapes between tympanic membrane and stapes foot plate.
Both devices are only intended for use by qualified medical personnel trained in the bridging of partial or complete auditory ossicle defects.
KURZ Tuebingen Titanium Prostheses (TTP) BELL + AERIAL VARIO are length-variable sterile middle ear prostheses. They are identical to the previously cleared devices with the following exceptions: Instead of eight (8) and fourteen (14) fixed-length sizes (Bell and Aerial respectively), the TTP VARIO models come in one size only. The head plate slides on the shaft and can be irreversibly attached at the exact length point required for the patient. The extra shaft length is cut off behind the head plate (s. Package Insert and Manufacturer's Instructions).
The provided document describes a 510(k) premarket notification for a device change to existing middle ear prostheses (Tuebingen Titanium Prosthesis (TTP) BELL VARIO and AERIAL VARIO). The change involves making the prostheses length-variable rather than having fixed-length sizes.
Here's an analysis of the acceptance criteria and the study reported in the document:
1. Table of Acceptance Criteria and Reported Device Performance:
| Acceptance Criteria (Stated or Implied) | Reported Device Performance and Evidence |
|---|---|
| Mechanical Stability/Strength of the Connection | Tensile strength tests at approximately seven times the middle ear forces acting on the implant have proven the stability of the connection. This demonstrates that the length-adjustable mechanism maintains structural integrity under stress. |
| Safety and Effectiveness (comparable to predicate devices) | The Reason for Design Modification states: "This modification does not affect the safety and effectiveness of the previously cleared devices". The Information Bearing on the Safety and Effectiveness section reiterates: "With the exception of the described design change, there are no additional characteristics known that should adversely affect the safety and effectiveness of these implants. The results of design validation raise no new issues of safety and effectiveness." The comparison table explicitly states that the implant is "as safe and effective as the previously cleared Tuebingen Bell Partial Prosthesis" and "as safe and effective as the previously cleared Tuebingen Aerial Total Prosthesis" based on the tensile strength tests. |
| Biocompatibility/Material Safety | The material remains ASTM F67 Titanium, which is the same as the predicate devices and is widely accepted as biocompatible. |
| Sterility | The device is reported as "Sterile: Yes", implying compliance with established sterilization standards. The document also mentions compliance with "device-related standards that apply to the manufacture, packaging, labeling, sterilization". |
| MRI Compatibility (lack of movement, adverse tissue effects, significant image impediment) | Testing in a 0.5 Tesla nuclear magnetic resonance tomograph revealed no implant movement and no adverse tissue effects attributable to MRI-generated heating. It notes that "The image quality may be impeded or blurred in direct vicinity of the implant," but this is an accepted characteristic of metallic implants and not considered an adverse effect on safety. "To date, no report of hearing loss or other adverse effect has come to the attention of the manufacturer." |
| Intended Use (unchanged from predicate) | The document explicitly states: "The KURZ Tuebingen Titanium Prostheses (TTP) BELL and AERIAL VARIO have the same intended use as the previously cleared devices." This is also confirmed in the "Indications for Use" section and the comparison table. |
| Compliance with Industry Standards | KURZ certifies compliance with required ISO/EN/ASTM/AAMI/ANSI and other device-related standards. |
2. Sample size used for the test set and the data provenance:
- Sample Size for Test Set: Not explicitly stated. The document refers to "tensile strength tests" as evidence of performance, but the number of devices or iterations tested is not provided.
- Data Provenance: The document does not specify the country of origin for the tensile strength tests. It is likely internal testing by the manufacturer, Heinz Kurz GmbH Medizintechnik, which is located in Germany. The study is retrospective, as it focuses on demonstrating that the design change does not compromise the established safety and effectiveness of the existing predicate devices. It is a design validation study rather than a clinical trial.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- Number of Experts: Not applicable. The "ground truth" for the tensile strength tests would be physical measurements and engineering standards, not expert consensus in a clinical context.
- Qualifications of Experts: Not applicable in the traditional sense. The tests would be performed by engineers or technicians skilled in mechanical testing and quality control.
4. Adjudication method for the test set:
- Adjudication Method: Not applicable. This refers to the process of resolving discrepancies among multiple experts or datasets, which is not relevant for a mechanical tensile strength test.
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 is a medical device, specifically an implantable prosthesis, not an AI-powered diagnostic tool. Therefore, MRMC studies are not relevant.
6. If a standalone (i.e., algorithm only without human-in-the-loop performance) was done:
- Standalone Performance: Not applicable. This device is not an algorithm. Performance is assessed through mechanical testing and comparison to predicate devices, and its use requires human surgical intervention.
7. The type of ground truth used:
- Ground Truth: For the mechanical performance, the ground truth is based on engineering standards and physical measurements of tensile strength and stability. The criteria for "safe and effective as the previously cleared devices" serves as the comparative ground truth. For the MRI compatibility, the ground truth is observational data (no movement, no adverse tissue effects, acceptable image impediment) in an MRI environment.
8. The sample size for the training set:
- Sample Size for Training Set: Not applicable. This is not an AI/ML device that requires a training set. The design of the new devices is based on an existing, cleared design, with a modification to the length adjustment mechanism.
9. How the ground truth for the training set was established:
- Ground Truth for Training Set: Not applicable, as there is no training set for an AI/ML model for this device.
§ 874.3450 Partial ossicular replacement prosthesis.
(a)
Identification. A partial ossicular replacement prosthesis is a device intended to be implanted for the functional reconstruction of segments of the ossicular chain and facilitates the conduction of sound wave from the tympanic membrane to the inner ear. The device is made of materials such as stainless steel, tantalum, polytetrafluoroethylene, polyethylene, polytetrafluoroethylene with carbon fibers composite, absorbable gelatin material, porous polyethylene, or from a combination of these materials.(b)
Classification. Class II.