(88 days)
ISSDE is indicated for use with InterX Transcutaneous Electrical Nerve Stimulator. The ISSDE provides the conductive interface between the InterX stimulation device and the patient's skin. The ISSDE is not made with natural rubber latex, is reusable (single patient only), and is provided packaged and labeled as a sterile device, for single patient use. As a sterile device, the ISSDE can be applied to patients in a sterile post-operative healthcare setting. NRG only guarantees sterility for the first application, however, ISSDE can be repositioned and reapplied (single patient only) as a non-sterile device for subsequent applications. Refer to the labeling for reuse instructions.
The Proposed ISSDE is a flexible, sterile laminate composed of a top cover, a reinforcement film, dual conductive members with printed silver, biocompatible conductive hydrogel, a release liner which protects the hydrogel before use and during storage and a 2-conductor cable secured between the reinforcement film and the conductive members. The electrodes do not contain active electronics, software or firmware. The cable connects the dual-electrode to the Inter X electrical stimulation device. A single finished dual-electrode is placed into a protective pouch which is then sealed, gamma sterilized and boxed for shipment. The Proposed ISSDE is designed for single-patient/multiple application use.
The provided text describes the InterX Sterile Self-Adhesive Dual Electrode (ISSDE) and its performance against acceptance criteria, primarily through comparison to predicate devices, in the context of a 510(k) submission.
Here's an analysis of the acceptance criteria and study information:
1. Table of acceptance criteria and the reported device performance
The document presents a "Substantial Equivalence Table" comparing the ISSDE to three predicate devices for various characteristics, which effectively serves as the acceptance criteria and the reported performance. The "acceptance criteria" for the ISSDE are implicitly defined by its substantial equivalence to the predicate devices and compliance with relevant standards.
| Substantial Equivalence Item | Acceptance Criteria (Predicate Device Performance) | Reported Device Performance (ISSDE) |
|---|---|---|
| Sterile | Predicate 1: NO, Predicate 2: YES, Predicate 3: NO | YES |
| Intended Use | Varied (Non-sterile, reusable, stimulating electrode; Sterile, post-operative, stimulating electrode) | Sterile, post-operative, reusable, self-adhesive, stimulating electrode (single patient) |
| Indications for Use | Similar wording across predicates, emphasizing conductive interface for TENS/NMES/FES. | Provides conductive interface between InterX stimulation device and patient's skin. Latex-free, reusable (single patient only), sterile for single patient use. |
| Hydrogel Volume Resistivity | 2500 ohm-cm (max) for all predicates | 1500 ohm-cm (max) |
| Electrode Area (surface area) | Varied (50.23 cm², 57.64 cm², 47.47 cm²) | 67.58 cm² |
| Hydrogel Biocompatibility (ISO 10993) | Passed Cytotoxicity, Delayed Contact Hypersensitivity, Primary Skin Irritation Tests | Passed Cytotoxicity, Delayed Contact Hypersensitivity, Primary Skin Irritation Tests |
| Hydrogel Stainless Steel Adhesion (180° peel) | Varied (136 grams minimum, 180 grams minimum) | 136 grams minimum |
| Conductive Electrode Element | Varied (Carbon film with silver flood coated over entire surface, or gradient pattern) | Carbon film with silver flood coated over entire surface |
| Electrode Top Cover | Varied (Non-Conductive White Tricot, Non-Conductive White Polyethylene Foam, 31.25 mils thick) | Non-Conductive White Polyethylene Foam, 31.25 mils thick |
| Sterilization Method | Predicate 1: N/A, Predicate 2: Gamma Sterilized, Predicate 3: N/A | Gamma Sterilized |
| Storage Liner | Varied (Polyester with silicone release, Silicone coated bulk paper) | Polyester with silicone release |
| Electrode Lead Wire | Single conductor 24 AWG tinned copper with PVC jacket | 2-conductor cable, 24 AWG tinned copper with PVC jacket |
| Electrode Packaging | Sealed Pouch | Sealed Pouch |
| Number per Package | Varied (4, 2, 4) | 1 |
| Electrode Permanence | Disposable | Disposable |
| Patient Preparation | Clean Dry Skin | Clean Dry Skin |
| Electrode Placement | On Patient Skin In Intended Treatment Area | On Patient Skin In Intended Treatment Area |
| Latex Content | Latex Free / Not made with natural rubber latex | Not made with natural rubber latex |
| Electrode Impedance @ 1000 Hz | Less than 50 ohms | Less than 50 ohms |
| Wire Attachment Integrity (force to remove lead wire from electrode) | Varied (More than 10 lbs. force, More than 15 lbs. force) | More than 25 lbs. force |
| Connector Disengagement Force | Varied (More than 2 lbs. force, More than 1.75 lbs. force) | More than 2 lbs. force |
| Connector Design | Varied (Overmolded .080" single pole socket, .080" single pole socket with heat shrink) | Overmolded keyed connector with 2-pole 1.0 mm sockets, touch-proof |
| 21 CFR 898 Compatible? | Yes | Yes |
| Lead Wire to Electrode Attachment Method | Cyanoacrylate adhesive between wire insulation and silver film, tinned copper wire in contact | Cyanoacrylate adhesive between wire insulation and silver film, tinned copper wire in contact |
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 refers to "samples per electrode type" for impedance testing, but it does not specify the exact sample size number used for the test set for any of the performance tests (impedance, energy distribution, biocompatibility, adhesion, etc.).
The data provenance is from bench testing conducted by the manufacturer (Neuro Resource Group, Inc.) in the context of a 510(k) submission, confirming design verification. There is no mention of country of origin of the data or whether it was retrospective or prospective in the clinical sense, as the testing is purely on the device's physical and electrical characteristics.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts
This question is not applicable to this type of device and study. The "ground truth" here is objective physical and electrical measurements of the device's performance, compared against established engineering standards and predicate device performance. It does not involve expert interpretation or clinical assessment by medical professionals like radiologists.
4. Adjudication method (e.g. 2+1, 3+1, none) for the test set
This question is not applicable. Adjudication methods like 2+1 or 3+1 are typically used in studies involving human interpretation (e.g., image reading) where consensus among multiple reviewers is needed to establish ground truth. The tests described are objective measurements (e.g., impedance, adhesive strength) that do not require human adjudication to determine a "truth."
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
This question is not applicable as the device is a cutaneous electrode, not an AI-assisted diagnostic tool or an imaging modality that would involve human readers or AI assistance.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
This question is not applicable. The device is a passive electrode and does not contain an algorithm. The "performance" described is the electrode's physical and electrical properties, not an algorithm's output.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.)
The "ground truth" used for this device is based on:
- Established engineering standards: e.g., ISO standards (ISO 10993 for biocompatibility, ISO 11137 for sterilization) and FDA guidance for cutaneous electrodes.
- Physical and electrical measurements: Directly measuring properties like impedance, adhesion, and energy distribution.
- Performance of legally marketed predicate devices: The ISSDE's performance is compared against the pre-established characteristics of three predicate electrodes for "substantial equivalence."
8. The sample size for the training set
This question is not applicable. The device is a passive medical device (an electrode), not a machine learning or AI model that requires a "training set."
9. How the ground truth for the training set was established
This question is not applicable for the same reason as point 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).