(159 days)
The NeuroMetrix SENSUS Electrode is intended for use as disposable, conductive, adhesive interface between the patient's skin and a transcutaneous electrical nerve stimulator.
The SENSUS Electrode provides an electrically conductive interface between a transcutaneous electrical nerve stimulator and a patient's skin. It is provided non-sterile, is designed and intended for single patient use only, and to be disposable.
The SENSUS Electrode is comprised of four individual electrodes, each of size 36 by 46 mm. The overall dimensions are 50 by 280 mm. The individual electrodes are electrically connected in pairs such that the two outer electrodes constitute one pair and the two inner electrodes constitute a second pair. The SENSUS Electrode contains two conventional male snap connectors for electrical connection to a transcutaneous electrical nerve stimulator.
The SENSUS Electrode has a multi-layer design. The first and outermost layer is a sheet of Mylar. The second layer contains conductive silver traces and silver electrode pads. Where the silver traces are not covered by hydrogel, they are covered by a dielectric mask. The third layer is the four individual electrodes which consist of a medical grade, self adhering, biocompatible hydrogel (KM-10G, Katecho, Inc., Des Moines, IA). When not in use, the hydrogel is covered by a Mylar release liner. Two male type snap connectors interface the SENSUS Electrode to the transcutaneous electrical nerve stimulator. The patient facing surface of the snap connectors are either under hydrogel or covered by a laminated dielectric polypropylene layer. Therefore in both cases the snap connectors do not directly contact the patient's skin.
Here's a breakdown of the acceptance criteria and the study that proves the device meets them, based on the provided text:
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria / Performance Metric | Type of Test | Reported Device Performance/Result |
|---|---|---|
| Biocompatibility | Biocompatibility Testing (via related hydrogels) | KM-10G hydrogel's biocompatibility established by combining test results for KM-10B and KM-10P hydrogels (cleared in K000870) |
| Electrical Performance (AC Impedance) | Electrical Testing | Meets target specifications over a range of operating and storage conditions, including after 1 hour of conventional use |
| Electrical Performance (Current Dispersion) | Electrical Testing | Evaluated across the surface of the electrodes |
| Adhesive Performance (Skin Adhesion) | Adhesive Testing | Evaluated by performing a skin adhesion test |
| Electrode Stability (Electrical Performance under Normal Use) | Electrical Stability Testing | Met electrical impedance specifications after 1 hour of conventional use |
| Shelf-life Performance | Accelerated Aging Shelf-life Testing | Performs as intended over the course of its labeled shelf-life (expected 24 months) |
| Mechanical Properties (Snap Connector Resistance) | Mechanical Testing (Snap Connectors) | Measured the resistance of the connection |
| Mechanical Properties (Snap Connector Retention Force) | Mechanical Testing (Snap Connectors) | Measured the connection retention force |
| Compliance with ISO 10993-5:2009 (Cytotoxicity) | Standard Compliance Test | Conforms to the standard |
| Compliance with ISO 10993-10:2010 (Irritation & Skin Sensitization) | Standard Compliance Test | Conforms to the standard |
| Substantial Equivalence to Predicate Device | Overall Comparison and Testing | Verified through comparison of intended use, materials, technological characteristics, and non-clinical testing data |
2. Sample Size Used for the Test Set and Data Provenance
The document does not provide explicit sample sizes for the non-clinical tests (electrical, mechanical, biocompatibility). It states that NeuroMetrix determined that non-clinical (i.e., bench) testing was sufficient.
Regarding data provenance:
- Biocompatibility: The biocompatibility data is derived from related hydrogel formulations (KM-10B and KM-10P) from Katecho, Inc., which were previously cleared (K000870). This suggests a retrospective use of existing data from the hydrogel manufacturer.
- Electrical and Mechanical Testing: These appear to be prospective bench tests conducted on the SENSUS Electrode itself. The country of origin for this data is not specified, but the sponsor is NeuroMetrix, Inc. in Waltham, MA, USA, suggesting the testing was likely conducted in the USA or by a contract lab.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
This information is not applicable as the SENSUS Electrode is a device and its performance is evaluated through objective physical and electrical measurements, not by expert interpretation of images or signals. Therefore, there is no "ground truth" established by experts in the context of diagnostic accuracy.
4. Adjudication Method for the Test Set
This is not applicable as the evaluation relies on objective measurements and comparison to standards, not human interpretation that would require adjudication.
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
No, an MRMC comparative effectiveness study was not done. This type of study is relevant for diagnostic AI systems where human readers interpret medical data. The SENSUS Electrode is a physical medical device (an electrode), not a diagnostic AI system, so this type of study is not applicable.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was done
This question is not applicable as the SENSUS Electrode is a physical medical device, not an algorithm or AI system.
7. The Type of Ground Truth Used
The "ground truth" in this context is established by:
- Objective physical and electrical measurements: Such as impedance, current dispersion, adhesive strength, connection resistance, and retention force, compared against predefined target specifications.
- Compliance with recognized standards: ISO 10993-5:2009 (cytotoxicity) and ISO 10993-10:2010 (irritation and skin sensitization).
- Existing biocompatibility data: For the hydrogel, established by the manufacturer (Katecho, Inc.) through testing of related formulations.
- Substantial equivalence: To the predicate device, based on comparable intended use, materials, and technological characteristics.
8. The Sample Size for the Training Set
This information is not applicable as the SENSUS Electrode is a physical medical device and does not involve AI or machine learning models that require a training set.
9. How the Ground Truth for the Training Set was Established
This information is not applicable for the same reasons as #8.
§ 882.1320 Cutaneous electrode.
(a)
Identification. A cutaneous electrode is an electrode that is applied directly to a patient's skin either to record physiological signals (e.g., the electroencephalogram) or to apply electrical stimulation.(b)
Classification. Class II (performance standards).