(84 days)
MIST Systems produce a low energy ultrasound generated mist used to promote wound healing through wound cleansing and maintenance debridement by the removal of yellow slough, fibrin, tissue exudates, and bacteria.
MIST Systems (e.g., UltraMIST System) are low frequency ultrasound devices, which utilize a fluid (e.g., saline) mist to deliver the ultrasound to the treatment site. The atomized fluid allows the treatment to be performed without direct contact to the patient. MIST Systems are made up of a main generator component, treatment wand, and disposable applicator.
MIST Systems deliver low-frequency ultrasound to the treatment site using an atomized fluid mist. The mist is generated from a small, portable system consisting of a generator, a treatment wand (encasing an ultrasound transducer), and a disposable applicator that has been designed to connect to a user-provided fluid source (e.g., IV saline bag). The system provides a flow of fluid (irrigant) to the tissue surface by the use of low frequency, low intensity ultrasound. Only the mist touches the tissue, not the ultrasound radiation surface (horn tip), thus the term "non-contact" ultrasound. The flow of fluid as an irrigant is controlled by a peristaltic pump on the generator unit. The fluid is dispensed onto the ultrasound radiation surface where the mist is generated. The mist is projected by fundamental atomization or nebulization and acoustic streaming or acoustic radiation force respectively.
The acceptance criteria and device performance evaluation details for the Alliqua Biomedical, Inc. Stimucel System (K162721) are summarized below, based on the provided 510(k) summary.
It's important to note that this submission is a 510(k) for a device with minor modifications (enclosure material change) to an already cleared predicate device (K140782, UltraMIST® System). Therefore, the study presented focuses on demonstrating that these specific modifications do not adversely affect the safety and performance, rather than establishing original effectiveness for the first time. The information provided aligns with a non-clinical testing approach to establish substantial equivalence.
1. Table of Acceptance Criteria and Reported Device Performance
| Feature/Test | Acceptance Criteria (Predicate) | Reported Device Performance (Subject Device) |
|---|---|---|
| Control of Fluid Flow | Clamp on tubing line to stop and start fluid flow for priming purposes. Peristaltic pump used to provide consistent flow. | Same |
| Enclosures | Injection molded PC/ABS polymer and compound curvature | Geon HC 8210, Rigid Polyvinyl Chloride, Flammability rated V-0 |
| Supply Voltage and Current | 100-240VAC Universal input | Same |
| Input Frequency | 50-60Hz Universal input | Same |
| Rated Power | 100 watts (fuse limited) | Same |
| Distal Displacement of Radiation Surface | 65 ± 10 microns | Same |
| Acoustic Frequency | 40 ± 1 kHz | Same |
| Radiation Surface Diameter and Material | 0.390 in. ± 0.001 in. Titanium alloy (TI-6AL-4V) | Same |
| Single Patient Use Disposable Applicator | Injection molded PC/ABS polymer and compound curvature | Same |
| Packaging and Labeling | System: Non-sterile, reusable. Applicator: Sterile per ISO 11607. | Same |
| Method of Sterilization | Gamma radiation | Same |
| Shelf Life / Product Life Cycle | System: 5 years. Applicator: 3 years. | Same |
| Mode of Exudate and Bacterial Removal | Atomized mist. Acoustic and fluid stream delivery / washout. | Same |
| Microprocessor | Yes | Same |
| Patient Contact | None - fluid contact only via atomized mist | Same |
| Treatment Variables | Treatment duration based on area to be treated (algorithm) | Same |
| Generator (v0.8) Current Range | Current out of range narrower than original MIST System | Modified to be equivalent to that of the original MIST System |
| General Safety Testing (IEC 60601-1 3rd Ed.) | The system with the prior enclosure materials was safe and effective. | The system with the new enclosure materials was found to be as safe, as effective, and performed as well as the predicate device. |
| Biocompatibility Testing (Cytotoxicity) | The prior enclosure materials (for non-contact parts) were non-cytotoxic. | The new enclosure materials for the Generator and Treatment wand were determined to be non-cytotoxic, presenting no new or different biocompatibility issue. |
2. Sample Size for Test Set and Data Provenance
The submission does not detail a "test set" in the traditional sense of patient data. Instead, the testing described is related to the physical and electrical performance of the device components and biocompatibility of materials.
- General Safety Testing (IEC 60601-1 3rd Ed.): Performed on the subject device to verify changes in enclosure material. This would involve specific units of the manufactured device. The exact number of units tested is not specified in the summary but is typically dictated by testing standards.
- Biocompatibility Testing (Cytotoxicity): Performed on the new enclosure materials. This involves samples of the material itself. The exact number of samples is not specified.
Data Provenance: The non-clinical testing was performed by Intertek (for general safety) and WuXi AppTec (for biocompatibility), which are accredited testing laboratories. The data is thus derived from laboratory testing of the device and its materials. This is a form of prospective testing for the specific modifications. Country of origin of the data is not explicitly stated but generally follows the location of these testing facilities.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications of Experts
This type of information is not applicable for the non-clinical testing performed for this 510(k) submission. The "ground truth" for these tests are objective measurements against established engineering and safety standards (e.g., IEC 60601-1, ISO biocompatibility standards). The results are interpreted by qualified engineers and scientific personnel at the testing laboratories (Intertek, WuXi AppTec) who specialize in these types of evaluations.
4. Adjudication Method for the Test Set
Not applicable. The tests performed are objective, quantitative measurements against defined technical and safety specifications, rather than subjective assessments requiring adjudication.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done
No, an MRMC comparative effectiveness study was not done. This submission focuses on demonstrating substantial equivalence for minor material changes to an existing device through non-clinical performance and safety testing. MRMC studies are typically used to evaluate the diagnostic performance of imaging devices where human interpretation is involved.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was done
Not applicable. The device, UltraMIST, is a physical medical device (low energy ultrasound wound cleaner) and not a software algorithm evaluating data independently.
7. The Type of Ground Truth Used
For the non-clinical testing, the "ground truth" is based on:
- Established international standard performance requirements (e.g., IEC 60601-1 for electrical safety and performance).
- Biocompatibility standards for medical device materials (e.g., ISO standards for cytotoxicity).
- Comparison to the performance of the legally marketed predicate device (K140782), specifically demonstrating that the modified device's performance is equivalent.
8. The Sample Size for the Training Set
Not applicable. This device is not an AI/ML algorithm that requires a training set. The term "training set" is relevant for machine learning models, which is not what this device is.
9. How the Ground Truth for the Training Set Was Established
Not applicable, as no training set was used.
§ 878.4410 Low energy ultrasound wound cleaner.
(a)
Identification. A low energy ultrasound wound cleaner is a device that uses ultrasound energy to vaporize a solution and generate a mist that is used for the cleaning and maintenance debridement of wounds. Low levels of ultrasound energy may be carried to the wound by the saline mist.(b)
Classification. Class II (special controls). The special control is FDA's guidance document entitled “Class II Special Controls Guidance Document: Low Energy Ultrasound Wound Cleaner.” See § 878.1(e) for the availability of this guidance document.