(243 days)
The twion is a Power Assist Wheelchair Conversion Kit and suitable for the manual wheelchair users who are limited in their field of activities because of their physical conditions. The device can expand their field of activities by assisting their wheelchair operating force.
The twion is a power assist drive system. Its basic functionality can be compared to a power steering of a car. By pushing the push rim attached to the wheel, a motor assists in turning the wheel - like a power steering does when turning the steering wheel.
The intent of the twion device is to expand the field of activities for those wheelchair drivers who are limited in their physical condition.
The twion is designed to fit most standard manual wheelchairs available on the market. It is lightweight and with motors and batteries designed inside the wheelhubs it does not compromise the usability and safety of such wheelchairs. The twion can be driven without power assist very close to a manual wheelchair.
Each hub motor is equipped with a DC motor and an integrated battery. A push rim sensor detects the force applied by the wheelchair driver. An integrated microcontroller converts this signal into a proportional motor output which generates an additional torque to the wheel. This torque by itself is very low but enables the driver to drive the wheelchair manually.
The benefit for the wheelchair driver is such that he can keep driving in his manual wheelchair. Without a device like the twion, the patient would have to use a fully electrical wheelchair (with joystick).
The provided text is related to a 510(k) premarket notification for a medical device called "twion," a power-assist wheelchair conversion kit. Based on the document, this device is a mechanical one and performs its functions through mechanical means rather than artificial intelligence or an algorithm. Therefore, the questions related to AI/algorithm performance, such as acceptance criteria for AI, sample sizes for test and training sets for algorithms, expert ground truth establishment, MRMC studies, or standalone algorithm performance, are not applicable here.
The document focuses on demonstrating substantial equivalence to a predicate device (Yamaha JWX-2) through a comparison of physical characteristics and adherence to performance standards for wheelchairs.
However, I can extract information related to the device's performance based on the established safety and performance standards it was tested against.
Here's a breakdown of the relevant information:
1. A table of acceptance criteria and the reported device performance
The document does not explicitly present a table of "acceptance criteria" in terms of specific performance metrics with target values that the device must achieve and then reports the device's measured performance against those targets. Instead, it states that the device was tested against a series of national and international performance standards. The "acceptance criteria" are implied to be compliance with these standards, and the "reported device performance" is that it met all relevant requirements of these standards.
| Acceptance Criteria (Implied) | Reported Device Performance |
|---|---|
| Compliance with ISO 7176-21 (EMC of electric wheelchairs) | Met all relevant requirements of the standard. |
| Compliance with ISO 7176-15 (Information disclosure/labeling) | Met all relevant requirements of the standard. |
| Compliance with ISO 7176-14 (Power & control systems) | Met all relevant requirements of the standard. |
| Compliance with ISO 7176-8 (Static, Impact, Fatigue Strength) | Met all relevant requirements of the standard. |
| Compliance with ISO 7176-9 (Climatic tests) | Met all relevant requirements of the standard. |
| Compliance with ISO 7176-1 (Static stability) | Met all relevant requirements of the standard. |
| Compliance with ISO 7176-2 (Dynamic stability) | Met all relevant requirements of the standard. |
| Compliance with ISO 10993-5 (In vitro cytotoxicity) | Met all relevant requirements of the standard. |
| Compliance with ISO 10993-10 (Irritation and skin sensitization) | Met all relevant requirements of the standard. |
| Compliance with EN 12184:2009 (Electrically powered wheelchairs) | Met all relevant requirements of the standard. |
| Compliance with IEC 62133:2002 (Secondary cells and batteries) | Met all relevant requirements of the standard. |
| Compliance with IEC 62304:2006 (Medical device software) | Met all relevant requirements of the standard. |
| Compliance with ANSI/AAMI ES60601-1:2005 (General safety) | Battery charger was tested to this standard and met requirements. |
| Compliance with FDA 1993 Draft "Reviewer Guidance" (Electrical, Mechanical, Environmental, Performance Requirements) | Testing demonstrated safety and effectiveness and met all relevant requirements, with no design characteristics violating requirements or resulting in safety hazards. |
2. Sample size used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)
The document mentions "testing" and "non-clinical tests" but does not specify a "sample size" in the context of a test set of data. The testing refers to the device itself being subjected to various physical and electrical tests according to the listed standards. There is no mention of "data" in the sense of patient data or clinical images. The data provenance is also not applicable in this context; the tests were performed on the device by the manufacturer (Alber GmbH, based in Germany).
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, as this is a mechanical device subject to engineering and performance standards, not an AI/algorithmic device requiring expert review of generated outputs or interpretations.
4. Adjudication method (e.g. 2+1, 3+1, none) for the test set
Not applicable, for the same reasons as above.
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 not an AI-assisted diagnostic or interpretive tool that would involve human "readers."
6. If a standalone (i.e. algorithm only without human-in-the loop performance) was done
Not applicable. The "twion" is a power-assist conversion kit for manual wheelchairs, a mechanical device. It is not an algorithm or AI system.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc)
Not applicable. The "ground truth" for this device's performance is its direct compliance with established international and national engineering, safety, and performance standards for wheelchairs and electrical components.
8. The sample size for the training set
Not applicable, as there is no mention of a training set for an algorithm.
9. How the ground truth for the training set was established
Not applicable, as there is no mention of a training set for an algorithm.
§ 890.3860 Powered wheelchair.
(a)
Identification. A powered wheelchair is a battery-operated device with wheels that is intended for medical purposes to provide mobility to persons restricted to a sitting position.(b)
Classification. Class II (performance standards).