(30 days)
The firefly T-2 is intended for stimulation of healthy muscles in order to improve or facilitate muscle performance. The firefly™ T-2 is not intended to be used in conjunction with therapy or treatment of medical conditions of any kind.
The firefly™ T-2 Neuromuscular Stimulator (firefly™ T-2) is a disposable, fully integrated unit composed of a constant current pulse generator with embedded software and battery enclosed in an over-molded plastic casing, and a silver electrode with a hydrogel coating that provides a means of attachment of the device and electrical contact with the patient. Two buttons are used to control the On/Off function and increase or decrease the intensity level of the device output, which is achieved through changes in the delivered pulse width. The firefly™ T-2 is applied so that the electrodes lie over the common peroneal nerve behind the knee. Stimulation of the common peroneal nerve causes contraction of the calf muscles through the direct activation of the motor neurons, resulting in increased blood flow.
This document, K201131, is a 510(k) summary for the firefly™ T-2, a powered muscle stimulator. It is not a study proving the device meets acceptance criteria for a new AI/ML-driven medical device, but rather a submission demonstrating substantial equivalence to a predicate device.
Therefore, I cannot provide a table of acceptance criteria and reported device performance related to AI/ML accuracy metrics (e.g., sensitivity, specificity, AUC) or the other points typically associated with the rigorous validation of an AI/ML model (sample sizes for test/training, expert adjudication, MRMC studies, etc.).
The document focuses on comparing the firefly™ T-2 to its predicate device, the firefly™ T-1, based on technical specifications and functional performance, rather than clinical performance metrics, especially those that would require AI-specific validation.
Here's a breakdown of what the document does provide, and why it doesn't fit the requested AI/ML validation criteria:
Device Type and Purpose:
- The firefly™ T-2 is a powered muscle stimulator. Its "intended for stimulation of healthy muscles in order to improve or facilitate muscle performance."
- It is explicitly stated as not intended to be used in conjunction with therapy or treatment of medical conditions of any kind.
- It operates by stimulating the common peroneal nerve to cause calf muscle contraction, increasing blood flow. This is a biophysical mechanism, not an AI/ML-driven diagnostic or prognostic one.
Reason for Submission (Differences from Predicate):
- The firefly™ T-2 is a redesigned version of the firefly™ T-1. The redesign aimed for more efficient current delivery, shorter pulse widths, and improved prevention of current leakage between electrodes by using discrete hydrogel pieces.
- The user interface was also improved for ease of use.
- Crucially, the document states: "The changes resulting in the firefly™ T-2 device do not alter the device intended use, indications for use or fundamental scientific technology, and none of the changes significantly affect the safety or effectiveness of the device." This implies an engineering change, not a change incorporating AI/ML.
"Acceptance Criteria" implicitly addressed by the submission (not AI-specific):
The "acceptance criteria" here are implicitly related to demonstrating that the redesigned firefly™ T-2 is still substantially equivalent to the predicate firefly™ T-1 and continues to meet relevant safety and performance standards for a powered muscle stimulator.
- Safety Standards Compliance:
- IEC 60601-1:2005 + A1:2012 (Medical Electrical Equipment - General Requirements for Safety)
- IEC 60601-2-10:2016 (Particular requirements for the safety of nerve and muscle stimulators)
- IEC 60601-1-2: 2014 (Electromagnetic compatibility)
- ISO 10993-1:2009 (Biocompatibility of materials)
- Performance Verification (Comparison to Predicate):
- Output waveform characteristics (verified via oscilloscope).
- Output current measurements under various loads (compared to T-1).
- Validation of hardware and firmware functionality.
- Demonstration that the T-2 performs as designed and intended and is substantially equivalent to the T-1.
Why the requested AI/ML criteria are not applicable/found:
- AI/ML Specific Acceptance Criteria and Performance Table: Not applicable. The device is a muscle stimulator, not an AI/ML diagnostic.
- Sample Size for Test Set and Data Provenance: Not applicable for AI/ML validation. The "testing" refers to electrical and functional verification of the physical device, not an AI model trained on data.
- Number of Experts and Qualifications for Ground Truth: Not applicable. Ground truth for an AI model (e.g., disease presence in an image) isn't relevant here. The "ground truth" for this device is simply its physical and electrical properties conforming to specifications.
- Adjudication Method: Not applicable.
- Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study: Not applicable. This type of study assesses how AI assistive tools affect human reader performance in tasks like image interpretation. This device has no imaging component or human reader interaction for AI-driven interpretation.
- Standalone (Algorithm Only) Performance: Not applicable. There is no standalone algorithm in the sense of a medical AI.
- Type of Ground Truth Used: The "ground truth" for this device would be its engineering specifications and the physical laws governing electrical stimulation, verified through laboratory testing (e.g., oscilloscope measurements, impedance tests). It's not clinical "outcomes data" or "expert consensus" in the context of an AI model's output.
- Sample Size for Training Set & How Ground Truth for Training Set was Established: Not applicable. This device is not developed using AI/ML training data. Its "design" is based on electrical engineering principles and the performance of its predicate device, not on patterns learned from a large dataset.
In summary, the provided document is a regulatory submission for a powered muscle stimulator, focusing on demonstrating substantial equivalence to a predicate device through engineering changes and traditional electrical/mechanical testing, rather than the validation of an AI/ML medical device.
§ 890.5850 Powered muscle stimulator.
(a)
Identification. A powered muscle stimulator is an electrically powered device intended for medical purposes that repeatedly contracts muscles by passing electrical currents through electrodes contacting the affected body area.(b)
Classification. Class II (performance standards).