(338 days)
Reaxon® Plus is indicated for repair of peripheral nerve discontinuities up to 10 mm and where gap closure can be achieved by flexion of the extremity.
Reaxon® Plus is a flexible and transparent chitosan based implant designed for repair of peripheral nerve discontinuities up to 10mm and where gap closure can be achieved by flexion of the extremity.
Reaxon® Plus was developed to provide a protective environment for axonal growth across a nerve gap. When hydrated, Reaxon® Plus is an easy to handle, soft, pliable, transparent chitosan tube. Reaxon® Plus is provided sterile, non-pyrogenic, for single use in double blister packages in a variety of sizes as shown below.
The provided text is a 510(k) Summary for the Reaxon® Plus device, a nerve cuff. This type of document is for regulatory purposes to demonstrate substantial equivalence to a predicate device, not typically for reporting on a clinical effectiveness study with acceptance criteria in the way medical AI devices often do (e.g., sensitivity, specificity for diagnostic tasks).
Therefore, some of the requested information, specifically related to "acceptance criteria" for diagnostic performance, "sample size for the test set," "number of experts," "adjudication method," "multi-reader multi-case (MRMC) comparative effectiveness study," "standalone performance," and "training set details" are not applicable or explicitly stated in this document because it outlines a series of biocompatibility and performance bench tests for a physical medical implant.
However, I can extract the "acceptance criteria" and "reported device performance" from the various tests conducted to demonstrate the safety and effectiveness of the Reaxon® Plus. These criteria are more about meeting safety standards and functional requirements compared to the predicate device.
Here's a breakdown of the available information:
1. Table of Acceptance Criteria and Reported Device Performance:
| Test Name | Acceptance Criteria | Reported Device Performance |
|---|---|---|
| Cytotoxicity | Grade less than 2 (mild reactivity) - No evidence of cell lysis or toxicity. | No cytotoxicity. No evidence of cell lysis or toxicity. The test article extract met the requirements, with a grade less than a grade 2. |
| Acute Systemic Toxicity | No mortality or evidence of systemic toxicity. | No mortality or evidence of systemic toxicity from the extracts injected into mice. Each test article extract met the requirements. |
| Sensitization | No evidence of causing delayed dermal contact sensitization. | The test article extracts showed no evidence of causing delayed dermal contact sensitization in the guinea pig. It was not considered a sensitizer. |
| Irritation/Intracutaneous Reactivity | Difference between test extract overall mean score and corresponding control overall mean score is 0.0 for Sodium chloride and 0.2 for Sesame Oil. | No irritation. The stated differences were met. |
| Subacute Toxicity | No evidence of systemic toxicity. Classified as non-irritant compared to the control. | No subacute toxicity. No evidence of systemic toxicity from the test article following subcutaneous implantation in the rat. Classified as non-irritant compared to the control article. |
| Implantation (Local Tissue Response) | Macroscopic reaction not significant compared to negative control. Microscopically, classified as non-irritant compared to negative control. | The macroscopic reaction was not significant as compared to the negative control article. Microscopically, the test article was classified as a non-irritant as compared to the negative control article. |
| Pyrogenicity | Total rise of rabbit temperatures during the 3-hour observation period within acceptable USP limits. | Non-pyrogenic. The total rise of rabbit temperatures was within acceptable USP limits. |
| Genotoxicity (Bacterial Reverse Mutation) | No mutagenic changes (no two-fold or greater increase in revertants compared to negative control plates). | The DMSO and saline test article extracts were considered to be nonmutagenic to S. typhimurium and E. coli tester strains. |
| Genotoxicity (Mouse Lymphoma Assay) | No two-fold or greater increase in the mean mutant frequency. | The RPMIo and DMSO test article extracts did not cause a two-fold or greater increase in the mean mutant frequency of the L5178Y/TK* cell line. The test article was not mutagenic. |
| Genotoxicity (Mouse Peripheral Blood Micronucleus) | No induction of micronuclei. | The test article extracts did not induce micronuclei in mice. |
| Long-term Implantation | Slow degradation process and very mild tissue response. Stability, low macrophage count, and thin fibrotic layer. | Demonstrated slow degradation and very mild tissue response. Low number of activated macrophages, good stability, and marginal signs of degradation until 50 weeks, first significant macroscopic signs at 74/77 weeks. Biological tissue response stable at 3 months, with decreasing macrophages and fibrotic layer thickness. |
| Dimensional/Visual Inspection | Dimensions within specified tolerances following ethylene oxide sterilization. | Verified that the dimensions of the Reaxon® Plus were within specified tolerances following ethylene oxide sterilization. |
| Suture Retention Strength | Sufficient strength to resist suture pull-out under loads exceeding those anticipated in the intended use environment. | Suture retention strength testing verified that Reaxon® Plus has sufficient strength to resist suture pull-out under loads exceeding those anticipated in the intended use environment. |
| Compression and Rebound Analysis | Can withstand compressive forces greater than 0.25 N and will re-open following removal of compressive forces sufficient to collapse the nerve guide. | Compression and rebound analysis verified that the Reaxon® Plus can withstand compressive forces greater than 0.25 N and it will re-open following removal of compressive forces sufficient to collapse the nerve guide. The device is flexible to accommodate movement of joint while retaining its shape and is resistant to occlusive forces. |
2. Sample Size Used for the Test Set and Data Provenance:
- Cytotoxicity: Triplicate monolayers of L-929 mouse fibroblast cells.
- Acute Systemic Toxicity: Five mice.
- Sensitization: Ten test guinea pigs per extract, five control guinea pigs per vehicle.
- Irritation/Intracutaneous Reactivity: Three rabbits, five separate injection sites on each.
- Subacute Toxicity: Animals (rats) – specific number not provided but states "animals were observed."
- Implantation (Local Tissue Response): Animals (rabbits) – specific number not provided.
- Pyrogenicity: Three rabbits.
- Genotoxicity (Bacterial Reverse Mutation): Triplicate plates for each of five tester strains (Salmonella typhimurium TA98, TA100, TA1535, TA1537, and Escherichia coli WP2uvrA) with and without metabolic activation. Parallel testing with negative and positive controls.
- Genotoxicity (Mouse Lymphoma Assay): Duplicate tests for each test extract and negative control.
- Genotoxicity (Mouse Peripheral Blood Micronucleus Study): Twelve mice per test article extract (six per sex), six animals per sex for negative control, and six animals per sex for positive control.
- Long-term Implantation: Wistar rats, 10 mm rat sciatic nerve defect. Number of animals not specified, but various implantation times (12, 24, 50, 74/77 weeks) indicate a longitudinal study.
- Dimensional/Visual Inspection: Reaxon® Plus tubes (number not specified).
- Suture Retention Strength: Reaxon® Plus tubes (number not specified).
- Compression and Rebound Analysis: 1 cm of each tube (number not specified).
Data Provenance: The studies are primarily in-vitro (cell cultures) and animal studies (mice, guinea pigs, rabbits, rats). The studies appear to be prospective, designed specifically for this regulatory submission. Country of origin not explicitly stated but Medovent GmbH is based in Germany.
3. Number of Experts Used to Establish Ground Truth and Qualifications:
Not applicable in the context of these biocompatibility and bench tests. The "ground truth" here is based on objective laboratory measurements, animal observations, and histological examinations by trained personnel.
4. Adjudication Method:
Not applicable. These are laboratory and animal studies with objective measurements, not subjective evaluations requiring adjudication.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study:
No, this type of study was not conducted as it is not relevant for a physical implant like a nerve cuff. This study design is typically for diagnostic imaging devices where human interpretation is involved.
6. Standalone Performance Study:
Yes, all the listed studies represent standalone performance evaluations of the Reaxon® Plus device itself, often compared against established negative/positive controls or, for mechanical aspects, against its predicate device (NeuraGen® Nerve Guide). The "standalone" here refers to the device's intrinsic properties and biological interactions as measured in a controlled setting, not an algorithm's performance.
7. Type of Ground Truth Used:
The ground truth for these studies is based on:
- In-vitro measurements: (e.g., cell morphology, reactivity grades for cytotoxicity, revertant counts for genotoxicity)
- Animal observations and clinical signs: (e.g., systemic toxicity, dermal reactions, body weight, pyrogenic response, general health)
- Histopathology/Microscopic evaluation: (e.g., tissue response at implantation sites, cellular degeneration, macrophage presence, fibrotic layer thickness)
- Mechanical and Physical Measurements: (e.g., dimensions, force required for suture retention, compression force, rebound)
8. Sample Size for the Training Set:
Not applicable. This is not an AI/machine learning device that would have a training set.
9. How the Ground Truth for the Training Set Was Established:
Not applicable.
§ 882.5275 Nerve cuff.
(a)
Identification. A nerve cuff is a tubular silicone rubber sheath used to encase a nerve for aid in repairing the nerve (e.g., to prevent ingrowth of scar tissue) and for capping the end of the nerve to prevent the formation of neuroma (tumors).(b)
Classification. Class II (performance standards).