(446 days)
The DIXI Medical Intraoperative Subdural Electrodes (Strips and Grids) are intended for intraoperative use for less than or equal to 24 hours with recording and stimulation equipment for the recording and stimulation of electrical signals on the surface level of the brain. The recording of electrical activity supports brain mapping.
The DIXI Medical Intraoperative Subdural Electrode (Strips and Grids) is an intra-cranial electrode used intraoperatively on the surface of the brain. The device is designed for electroencephalography (EEG) recording and brief stimulation for brain mapping purposes. The DIXI Medical Intraoperative Subdural Electrode consists of circular contacts sandwiched between two layers of silicone substrate. The brain contacting side of the silicone substrate body has material removed to expose an amount of contact surface area. Insulated wires extend from each contact through a flexible tube which terminates in connectors for direct connection to user's equipment.
The device in question is the DIXI Medical Intraoperative Subdural Electrodes (Strips and Grids), which are intended for intraoperative use (less than or equal to 24 hours) for recording and stimulating electrical signals on the brain's surface to support brain mapping.
Here's an analysis of the acceptance criteria and the study that proves the device meets them:
1. Table of Acceptance Criteria and Reported Device Performance:
The document describes non-clinical and biocompatibility testing. The acceptance criteria are implicit in the "Objective" column for non-clinical tests and the "Conclusion" column for biocompatibility tests, which all show a "Pass" result indicating the device met the predefined safety and performance standards for each test.
| Test Performed | Objective / Reported Device Performance | Conclusion / Outcome |
|---|---|---|
| Nonclinical Testing | ||
| Dimensional Characteristics | Verification of electrodes dimensional characteristics | Pass |
| Electrical Characteristics | Verification of the electrodes ability to transmit a stimulation signal | Pass |
| Electrical Characteristics | Verification of the electrodes resistance to a stimulation signal under worst case charge density condition | Pass |
| Electrical Characteristics | Verification of the electrodes resistance to a stimulation signal under worst case current condition | Pass |
| Electrical Characteristics | Verification of the electrodes dielectric strength | Pass |
| Electrical Characteristics | Verification of electrodes stability under conditions of use (absence of corrosion) | Pass |
| Mechanical Characteristics | Verification of the resistance to torsion of the active part and silicon sheath | Pass |
| Mechanical Characteristics | Verification of electrodes resistance to bending | Pass |
| Mechanical Characteristics | Verification of electrodes resistance to traction | Pass |
| Biocompatibility Testing | ||
| Cytotoxicity | Percent viability of test article was 93.9%, 98.6%, and 88.5% of reagent control (across three tests). | Non-cytotoxic |
| Sensitization | Topical application of the 0.9% sodium chloride extract and the sesame oil extract did not induce delayed sensitization in the guinea pig. | Non-sensitizer |
| Intracutaneous Reactivity | Difference between each test extract overall mean score and corresponding control blank overall mean score was lower than 1.0 (0.0 for the 0.9% sodium chloride extract and sesame oil test extracts). | Non-irritant |
| Pyrogenicity | No rabbit showed an individual temperature rise higher or equal to 0.5℃ above its initial temperature. | Non-pyrogenic |
| Indirect (extract) Hemolysis | Mean hemolytic index for test article extract was of 0.0%. | Non-hemolytic |
| Acute Systemic Toxicity | No evidence of significant systemic toxicity or mortality after test article extracts injection. | Non-toxic |
2. Sample Sizes Used for the Test Set and Data Provenance:
- Test Set Sample Size: The document mentions that nonclinical testing was conducted on specific product references: C10-04CIOM, C10-08AIOM, and C10-16CIOM, C10-16AIOM for biocompatibility. However, it does not specify the exact number of units of each product that were tested for each individual test. It also refers to testing on "baseline and aged devices," with aged devices undergoing three sterilization cycles, accelerated aging (5 years), extreme climatic conditions, and transport tests, implying multiple units were used for aging studies.
- Data Provenance: The document does not explicitly state the country of origin of the data. It is a submission by DIXI Medical, located in France. The testing was conducted according to international standards (ASTM and ISO). The data is from nonclinical, pre-market testing, not patient-derived data (retrospective or prospective).
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications:
This information is not applicable. The studies described are non-clinical (device performance and biocompatibility) and do not involve expert-established ground truth in the context of clinical decision-making or diagnosis. The "truth" or acceptance criteria are based on established engineering and biological safety standards.
4. Adjudication Method for the Test Set:
This information is not applicable. Adjudication methods like 2+1 or 3+1 are typically used in clinical studies involving human readers or expert consensus on patient data. The current studies are bench tests and animal studies (for biocompatibility).
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study:
No, a Multi-Reader Multi-Case (MRMC) comparative effectiveness study was not done. This type of study is relevant for diagnostic or AI-assisted interpretation devices to compare human performance with and without AI. The DIXI Medical Intraoperative Subdural Electrodes are physical medical devices for electrical signal recording and stimulation, not for diagnostic image interpretation or AI-driven analysis.
6. Standalone Performance Study:
Yes, standalone (algorithm only without human-in-the-loop performance) studies were done for the device's physical and electrical characteristics and biocompatibility. The reported "Pass" results for all tests indicate the device met its predefined performance and safety criteria independently. The non-clinical and biocompatibility tests were conducted directly on the device itself or its materials.
7. Type of Ground Truth Used:
The "ground truth" for these tests refers to established engineering specifications, regulatory standards, and biological safety limits. For example:
- Nonclinical Testing: Ground truth is defined by the expected electrical (e.g., ability to transmit signal, resistance), dimensional, and mechanical properties of the device as per its design and intended use, validated against engineering standards.
- Biocompatibility Testing: Ground truth is based on the biological response limits defined by standards like ISO 10993, ensuring materials are non-cytotoxic, non-sensitizing, non-irritant, non-pyrogenic, non-hemolytic, and non-toxic.
8. Sample Size for the Training Set:
This information is not applicable. The device is a physical medical device, not an AI or machine learning algorithm that requires a "training set" in the conventional sense. The development of the device would have involved iterative design and testing, but not a formally defined "training set" for an algorithm.
9. How the Ground Truth for the Training Set Was Established:
This information is not applicable for the reasons stated in point 8.
§ 882.1310 Cortical electrode.
(a)
Identification. A cortical electrode is an electrode which is temporarily placed on the surface of the brain for stimulating the brain or recording the brain's electrical activity.(b)
Classification. Class II (performance standards).