(232 days)
As an NMES device, the Ttech NMES is indicated for the following conditions:
- Relaxation of muscle spasms .
- . Prevention or retardation of disuse atrophy
- Increasing local blood circulation .
- . Muscle re-education
- Immediate post-surgical stimulation of calf muscles to prevent . venous thrombosis; and
- t Maintaining or increasing range of motion
The Ttech NMES is a dual channel NMES device that produces a mild electrical current that is transmitted via leads to electrodes placed on the skin in areas predetermined by the clinician. The device, a set of electrodes with their lead wires, a battery (9 volt), carrying case, and instructions for use make up the Ttech NMES system.
The provided document is a 510(k) premarket notification for the Ttech NMES device. It details the device's characteristics and compares it to predicate devices to establish substantial equivalence. However, it does not contain specific acceptance criteria or an analytical study that proves the device meets such criteria in the way typically found for AI/ML-based medical devices with performance metrics like sensitivity, specificity, etc.
Instead, the document focuses on bench testing to demonstrate safety and performance equivalence to existing predicate devices. The conclusion explicitly states: "Bench testing raised no additional patient safety or performance issues so clinical testing was not indicated." This implies equivalence was established through non-clinical means.
Therefore, many of the requested details about acceptance criteria, sample sizes for test/training sets, expert ground truth, MRMC studies, or standalone algorithm performance are not applicable or present in this document.
Here's an attempt to answer the questions based on the provided text, while highlighting what is not present:
Acceptance Criteria and Study Details for Ttech NMES
1. Table of Acceptance Criteria and Reported Device Performance
The acceptance criteria are implicitly met by demonstrating that the Ttech NMES device performs "Good" in critical functions like "Current pulse regulation" and that its output parameters are within a range comparable to the predicate devices. The study performed was primarily bench testing to ensure safety and performance equivalence, rather than a clinical trial measuring specific performance metrics against pre-defined acceptance thresholds.
| Feature / Performance Metric | Acceptance Criteria (Implicitly based on Predicate Devices) | Reported Device Performance (Ttech NMES) | Predicate Device 1 (EMPI Focus) Performance | Predicate Device 2 (RESTIM) Performance |
|---|---|---|---|---|
| Current pulse regulation | Good | Good | Good | Good |
| Maximum output current | Comparable to or within acceptable range of predicates | 93mA | 60mA | 90mA |
| Load range | Comparable to or within acceptable range of predicates | 8ohm to open circuit | 8ohm to 10Kohm | 8ohm to open circuit |
| Maximum output voltage | Comparable to or within acceptable range of predicates | +100V | +120V | +55V |
| Maximum phase charge | Comparable to or within acceptable range of predicates | 21uC | 3.12 uC | 2.73 uC |
| Peak current density | Comparable to or within acceptable range of predicates | 0.125MAKm² | 7.92mA/cm² | 12.45 mA/cm² |
| Maximum Power Density | Comparable to or within acceptable range of predicates | .0058W/cm² | 4.09X10-5W/cm² | 4.29X10-6W/cm² |
| Patient Lead Safety | Compliance with 21 CFR 898 (Pass/Fail) | Testing Completed (Implied Pass) | N/A - Not explicitly stated for predicates | N/A - Not explicitly stated for predicates |
| Open/Short Circuit | Functional (Pass/Fail) | Testing Completed (Implied Pass) | N/A | N/A |
| Temperature Endurance | Functional (Pass/Fail) | Testing Completed (Implied Pass) | N/A | N/A |
| Incorrect battery install. | Functional (Pass/Fail) | Testing Completed (Implied Pass) | N/A | N/A |
| Vibration Test | Functional (Pass/Fail) | Testing Completed (Implied Pass) | N/A | N/A |
| Mechanical Shock Test | Functional (Pass/Fail) | Testing Completed (Implied Pass) | N/A | N/A |
| Humidity endurance test | Functional (Pass/Fail) | Testing Completed (Implied Pass) | N/A | N/A |
| Water immersion endurance | Functional (Pass/Fail) | Testing Completed (Implied Pass) | N/A | N/A |
2. Sample size used for the test set and the data provenance
Not applicable. The document describes non-clinical "bench testing" and does not refer to a "test set" in the context of patient data for performance evaluation. The data provenance would be laboratory testing in a controlled environment.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts
Not applicable. No expert ground truth on patient data was established, as no clinical testing was performed or deemed necessary.
4. Adjudication method for the test set
Not applicable. No test set involving human interpretation and adjudication was used.
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 powered muscle stimulator (NMES), not an AI/ML-based diagnostic or assistive technology for human readers. No MRMC study was performed.
6. If a standalone (i.e., algorithm only without human-in-the-loop performance) was done
Not applicable. This device is electro-mechanical, not an algorithm.
7. The type of ground truth used
For the safety and performance features, the "ground truth" was established through engineering standards and specifications (e.g., 21 CFR 898 for patient lead safety) and direct comparison of electrical output parameters against established values for predicate devices. There is no biological or clinical "ground truth" like pathology or outcomes data mentioned in this submission.
8. The sample size for the training set
Not applicable. As this is not an AI/ML device, there is no "training set."
9. How the ground truth for the training set was established
Not applicable. See point 8.
§ 890.5850 Powered muscle stimulator.
(a)
Identification. A powered muscle stimulator is an electrically powered device intended for medical purposes that repeatedly contracts muscles by passing electrical currents through electrodes contacting the affected body area.(b)
Classification. Class II (performance standards).