(783 days)
Portable Electro-Stimulation Therapy Device, model LGT-231 is to be used by adults only and has two modes NMES and TENS.
NMES is used to: stimulate healthy muscles in order to improve or facilitate muscle performance.
TENS is used to:
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Temporary relief of pain associated with sore and aching muscles due to strain from exercise or normal household and work activities.
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Symptomatic relief and management of chronic, intractable pain and relief of pain associated with arthritis.
The Portable Electro-Stimulation Therapy Device, model LGT-231 is a dual channel stimulator which sends gentle electrical current to underlying nerves and muscle group via electrodes applied on the skin with two operational modes and powered by rechargeable lithium battery; the device system is made up of mobile app MStim Reha, main unit and electrodes.
The Mobile App MStim Reha provides access to treatment controls for Portable Electro-Stimulation Therapy Device from a compatible device for selecting a pre-programmed output mode, adjusting frequency, pulse width and treatment time. Software operating environment of Mobile App MStim Reha are Android 4.3 or later mobile phone, with 4.0 Bluetooth and iOS 8.0 or later iPhone mobile phone, with 4.0 Bluetooth. Click the MStim Reha Application installation package on the phone to install the application. MStim Reha Application and the device can be connected via Bluetooth.
The main unit provides access to adjust the intensity up or down, put ON/OFF the main unit.
The two modes that Portable Electro-Stimulation Therapy Device, model LGT-231 employs are neuromuscular electrical stimulation (NMES) and transcutaneous electrical stimulation (TENS). Neuromuscular electrical stimulation (NMES) and transcutaneous electrical stimulation (TENS) target different nerve groups of the body.
TENS is specifically targets the sensory nerves, which are responsible for sending pain signals to the brain. TENS use tiny electrical impulses sent through the skin to nerves to modify the pain perception. TENS does not cure any physiological problem; it only helps control the pain, this activates the underlying sensory nerves. Self-adhesive electrodes are placed on the skin close to the area of pain.
NMES targets the muscle itself, specifically through the motor nerves. This allows the NMES machine to create a muscle contraction to recruit more muscle fibers when training: warming up or recovering. The Portable Electro-Stimulation Therapy Device stimulates nerve fibers by means of electrical impulses transmitted by electrical pulses generated by the Portable Electro-Stimulation Therapy Device stimulate motor nerves to stimulate a muscular response. Depending on the parameters of the electrical impulses (pulse frequency, duration of contraction, duration of rest, and total session duration), different types of muscle work can be imposed on the stimulated muscles. The Portable Electro-Stimulation Therapy Device may therefore be considered a technique of muscle training.
This document is a 510(k) Premarket Notification from Guangzhou Longest Science & Technology Co., Ltd. for their Portable Electro-Stimulation Therapy Device, model LGT-231. The notification seeks to establish substantial equivalence to a predicate device (Compex Sport Elite, K170918) and therefore does not contain acceptance criteria or study data in the way a clinical trial or performance study for a novel device would. Instead, it focuses on demonstrating that the device meets safety and performance standards equivalent to the predicate device.
Based on the provided information, here's a breakdown:
1. Table of Acceptance Criteria and Reported Device Performance
The document does not explicitly present "acceptance criteria" for a specific performance metric of the device in a comparative study against a clinical endpoint. Instead, the "acceptance criteria" are implied by demonstrating equivalence to a predicate device and adherence to recognized standards. The "reported device performance" is presented as its technical specifications and compliance with those standards, rather than clinical outcomes.
Here's a table summarizing the comparison to the predicate device, highlighting where the subject device "meets" or is considered "similar" to the predicate, thus satisfying the substantial equivalence requirement.
| Characteristic | Subject Device (LGT-231) | Predicate Device (Compex Sport Elite) | Discussion of Difference/Equivalence |
|---|---|---|---|
| General Characteristics | |||
| Classification | 21 CFR 890.5850, 21 CFR 882.5890 | 21 CFR 890.5850, 21 CFR 882.5890 | Same |
| Prescription/OTC | OTC | OTC | Same |
| Product Code | NGX, NUH, NYN | NGX, NUH, NYN | Same |
| FDA Class | II | II | Same |
| Intended Use | NMES: stimulate healthy muscles to improve/facilitate muscle performance. TENS: temporary relief of pain associated with sore/aching muscles, symptomatic relief/management of chronic, intractable pain, and arthritis pain relief. For adults only. | NMES: stimulate healthy muscles to improve/facilitate muscle performance. TENS: temporary relief of pain associated with sore/aching muscles, symptomatic relief/management of chronic, intractable pain, and arthritis pain relief. For adults only. | Same (Minor wording differences, but identical indications) |
| Target Population | Adults | Adults | Same |
| Power Source | Rechargeable lithium battery 3.7V | Rechargeable Ni-Mh Battery 4.8V | Similar: "The proposed device was demonstrated electromagnetic compatibility and electrical safety by the testing. The difference does not raise the issue of product's safety and effectiveness." |
| Method of Line Current Isolation | N/A (battery operated device) | N/A (battery operated device) | Same |
| Patient Leakage Current (Normal) | N/A (battery operated device) | N/A (battery operated device) | Similar: "The proposed device was demonstrated electrical safety by passing ANSI AAMI ES60601-1 and IEC 60601-2-10 tests. The difference does not raise the issue of product's safety and effectiveness." |
| Patient Leakage Current (Single Fault) | N/A (battery operated device) | N/A (battery operated device) | Same |
| Number of Output Channels | Two | Four | Different: "More channels means it can be applied on more different body sides at the same time, and all output channel works independently from each other, the proposed device has less channels than equivalent device, this can be addressed by applied two proposed device, therefore, the different channel number will not affect the safety and effectiveness of the proposed device." |
| Synchronous or Alternating? | Synchronous | Synchronous | Same |
| Method of Channel Isolation | Isolating transformer | Each channel is the middle of a H-Bridge. | Similar: "The proposed device was demonstrated electrical safety by passing ANSI AAMI ES60601-1 and IEC 60601-2-10 tests. The difference in Method of Channel Isolation does not raise the issue of product's safety and effectiveness." |
| Number of Output Modes | Two (TENS and NMES) | Two (TENS and NMES) | Same |
| Regulated Current or Voltage? | Current | Current | Same |
| Software/Firmware/Microprocessor Control? | Yes | Yes | Same |
| Automatic Overload Trip? | Yes | Yes | Same |
| Automatic No-Load Trip? | Yes | Yes | Same |
| Automatic Shut Off? | "On/Off" button | "On/Off" switch | Same |
| User Override Control? | Yes | Yes | Same |
| Indicator: On/Off Status? | Yes | Yes | Same |
| Display: Low Battery? | Yes | Yes | Same |
| Display: Voltage/Current Level? | Yes (on app) | Yes | Same: "System validation testing scenarios covering mitigation of wireless risks in accordance with RED were added to our full system testing protocol to ensure safe and effective use." |
| Timer Range (minutes) | Maximum = 60 minute | Maximum = 55 minute | Different: "The treatment time is adjusted by the user or depend on selected programs, so the difference doesn't affect the safety and effectiveness of the proposed device." |
| Compliance with 21 CFR 898? | Yes | Yes | Same |
| ANSI AAMI ES60601-1 | Yes | Yes | Same |
| IEC 60601-2-10 | Yes | Yes | Same |
| Weight | 120g (only main unit) | 300 g | Different: "The Weight will not affect the safety and effectiveness of the proposed device." |
| Dimensions (mm) (W x H x D) | 62 (W) × 122 (L) × 27 (H) (mm) | 99 x 142 x 36 (mm) | Different: "The dimensions will not affect the safety and effectiveness of the proposed device." |
| Housing Materials and Construction | Casing: Plastic (PC+ABS, with PMMA on button panel). Buttons: ABS. Light pipe: PC | Casing: Plastic (ABS, with PMMA on windows). Buttons: Silicon, rubber. Battery Pack: Rigid, ABS housing. Battery contacts: SK5 steel. | Similar: "The Housing Materials and Construction form the basic construction and ensure the basic safety of device, since the proposed device was demonstrated electrical safety by passing ANSI AAMI ES60601-1 and IEC 60601-2-10 tests, the existed difference will not affect the safety of the proposed device." |
| Programs | NMES: (not detailed). TENS: Normal, Sweep, Random, Alternation (different frequency modulation methods). | NMES: Endurance, Resistance, Strength, Explosive Strength, Potentiation, Training Recovery, Competition Recovery, Pre-Warmup Program, Muscle Relaxation. TENS: Pain relief TENS (same as FM). | Similar: "The two devices have two same main Output Modes: NMES and TENS, both modes NMES and TENS of these two devices also have same indications respectively, although both modes have different output programs, these two modes have almost the same parameter range, and the NMES of the proposed device can be adjusted arbitrarily within the parameter range, the TENS output programs: Normal, Sweep, Random, Alternation represents different frequency adjustment methods, same as Frequency Modulation which is same with the equivalent device. Therefore, the existed difference will not affect the safety and effectiveness of the proposed device." |
| Output Specifications | |||
| Waveform | NMES: Symmetrical biphasic. TENS: Balanced Symmetrical biphasic (Normal, Random, Sweep, Alternation). | NMES: Symmetrical Biphasic (all programs). TENS: Balanced, asymmetrical Biphasic (Pain relief TENS). | Same (for NMES), Similar (for TENS, although stated as 'Same' in the table row, the text mentions "Balanced, asymmetrical Biphasic" for predicate TENS vs "Balanced Symmetrical biphasic" for subject TENS, this is not fully articulated in the discussion, but generally within a range expected not to raise new questions.) |
| Shape | NMES: Rectangular. TENS: Rectangular (all modes). | NMES: Rectangular (all programs). TENS: Rectangular (Pain relief TENS). | Same |
| Maximum Output Voltage (± 10%) | NMES: 50V @ 500Ω, 115V @ 2kΩ, 125V @ 10kΩ. TENS: Similar values for all modes. | NMES: 60V @ 500Ω, 165V @ 2kΩ, 165V @ 10kΩ. TENS: Similar values for Pain Relief TENS. | Similar: "The max output voltage of proposed device is smaller than predicate device, the predicate device is safe and effective with its output voltage range which means the proposed device is also safe and effective with its output voltage, and at the meantime, the proposed device was also demonstrated electrical safety by passing ANSI AAMI ES60601-1 and IEC 60601-2-10 tests. Therefore, the difference does not raise the issue of product's safety and effectiveness." |
| Maximum Output Current (± 10%) | NMES: 100mA @ 500Ω, 58mA @ 2kΩ, 13mA @ 10kΩ. TENS: Similar values for all modes. | NMES: 120mA @ 500Ω, 82mA @ 2kΩ, 16mA @ 10kΩ. TENS: Similar values for Pain Relief TENS. | Similar: "The output current of proposed device is smaller than predicate device, the predicate device is safe and effective with its output current range which means the proposed device is also safe and effective with its output current, and at the meantime, the proposed device was also demonstrated electrical safety by passing ANSI AAMI ES60601-1 and IEC 60601-2-10 tests. Therefore, the difference does not raise the issue of product's safety and effectiveness." |
| Pulse Width | NMES: 50 to 400 µs. TENS: 50 to 400 µs (all modes). | NMES: 200 to 400 [µs] (all programs). TENS: 70 to 300[µs]. | Similar: "Risk arises with larger Pulse Width, since the largest Pulse Width of proposed device is same the predicate device, this tiny differences will not affect the safety and effectiveness of the proposed device." |
| Frequency | NMES: 1 to 120 Hz. TENS: 1 to 120 Hz (all modes). | NMES: 1 to 100 Hz (most programs). TENS: 5 to 122 Hz. | Similar: "The different frequency will finally cause different feelings, as for NMES mode, the frequency range of the proposed device is 1 |
| Symmetrical phases? | Yes | Yes | Same |
| Phase Duration | NMES: Symmetrical, 50 - 400 µs. TENS: Symmetrical, 50 - 400 µs. | NMES: Symmetrical, 280 - 400 µs. TENS: Symmetrical, 70 - 300 µs. | Similar: "Risk arises with larger Pulse Width, since the largest Pulse Width of proposed device is same the predicate device, this tiny differences will not affect the safety and effectiveness of the proposed device." |
| Net Charge (µC/pulse) | NMES: 0 μC @ 500Ω. TENS: 0 μC @ 500Ω. | NMES: 0 [μC] @ 500Ω (Excitation pulse fully Compensated). TENS: 0 [μC] @ 500Ω (Excitation pulse fully compensated). | Same |
| Maximum Phase Charge (µC) | NMES: 48.24 μC @ 500Ω. TENS: 46.73 μC @ 500Ω. | 48 (μC) @ 500Ω. | Similar: "The tiny difference existed in Maximum Phase Charge between proposed device and predicate device are acceptable and the proposed device was demonstrated electrical safety by passing ANSI AAMI ES60601-1 and IEC 60601-2-10 tests. The difference does not raise the issue of product's safety and effectiveness." |
| Maximum Current Density (mA/cm², r.m.s.) | TENS: 1.94mA/cm² @ 500Ω. NMES: 2.00mA/cm² @ 500Ω. | 4.8 (mA/cm²) @ 500Ω. | Similar: "The proposed device has a smaller maximum current density than predicate device. The proposed device was also demonstrated electrical safety by passing ANSI AAMI ES60601-1 and IEC 60601-2-10 tests. The difference does not raise the issue of product's safety and effectiveness." |
| Maximum Average Power Density (mW/cm²) | TENS: 30.15 mW/cm² @500Ω. NMES: 32.28 mW/cm² @500Ω. | 27.6 (mW/cm²) @500Ω. | Similar: "The tiny difference existed in Maximum Average Power between proposed device and predicate device are acceptable and the proposed device was demonstrated electrical safety by passing ANSI AAMI ES60601-1 and IEC 60601-2-10 tests. The difference does not raise the issue of product's safety and effectiveness." |
| Burst Mode | N/A, no burst mode | N/A, no burst mode | Same |
| ON Time (seconds) | Depends on user settings. | Depends on selected program. | Same: "Both device is depended on the user's selection." |
| OFF Time (seconds) | Depends on user settings 1-60min. | Depends on selected program. | Same: "Both device is depended on the user's selection." |
2. Sample size used for the test set and the data provenance:
- Test Set Sample Size: The document does not describe any clinical test set involving human subjects to evaluate the device's therapeutic effectiveness. The non-clinical testing involved various electrical, mechanical, and software tests to demonstrate compliance with standards and equivalence to the predicate device.
- Data Provenance: Not applicable, as there isn't a clinical test set in the traditional sense for this 510(k) submission. The testing performed was non-clinical (bench testing, software verification) by the manufacturer in China.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- Not applicable. This 510(k) submission did not involve a clinical study requiring human experts to establish ground truth for a test set of data. The ground truth for the non-clinical tests was established by the technical specifications of the device and the requirements of the international safety and performance standards.
4. Adjudication method (e.g., 2+1, 3+1, none) for the test set:
- Not applicable. There was no clinical test set requiring adjudication.
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:
- Not applicable. This device is not an AI-powered diagnostic imaging system or similar technology that would involve human readers or AI assistance in interpretation. It is an electro-stimulation therapy device.
6. If a standalone (i.e., algorithm only without human-in-the-loop performance) was done:
- Not applicable. This refers to the performance of an algorithm without human intervention, typically for AI/ML-based devices. This device is a hardware electro-stimulation therapy device, not an algorithm.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.):
- For the non-clinical tests, the "ground truth" was based on:
- Technical Specifications: The declared specifications of the device itself.
- International Standards: Requirements defined by standards such as ISO 10993-5, ISO 10993-10, ANSI AAMI ES60601-1, ANSI AAMI ES60601-1-2, IEC 60601-2-10, and ANSI AAMI ES60601-1-11.
- Predicate Device Specifications: The established safety and performance characteristics of the legally marketed predicate device (Compex Sport Elite, K170918).
8. The sample size for the training set:
- Not applicable. This device does not use machine learning or AI that would require a "training set" of data.
9. How the ground truth for the training set was established:
- Not applicable, as there is no training set for this type of device.
Summary of the Study that Proves the Device Meets Acceptance Criteria:
The document states that non-clinical verification testing was performed to demonstrate that the Portable Electro-Stimulation Therapy Device, model: LGT-231 meets its design specifications and is suitable for its intended use. This testing established that the device is as safe, as effective, and performs as well as the predicate device (Compex Sport Elite, K170918), and that no new issues of safety and effectiveness were raised.
The "study" or evidence provided includes:
- Comparison to a Predicate Device (K170918 Compex Sport Elite): Detailed tables comparing the technological characteristics and output specifications of the subject device to the predicate device. For each difference identified, a discussion is provided to argue why the difference "does not raise the issue of product's safety and effectiveness" or why the devices are "similar" or "same."
- Compliance with International Standards: The device underwent testing to demonstrate compliance with a list of recognized consensus standards:
- ISO 10993-5:2009 (Biological evaluation - Cytotoxicity)
- ISO 10993-10:2010 (Biological evaluation - Irritation and skin sensitization)
- ANSI AAMI ES60601-1:2005+A1:2012 (Medical electrical equipment - General requirements for basic safety and essential performance)
- ANSI AAMI ES60601-1-2:2014 (Medical electrical equipment - Electromagnetic compatibility)
- IEC 60601-2-10:2012 (Particular requirements for the safety of nerve and muscle stimulators)
- ANSI AAMI ES60601-1-11:2015 (Medical electrical equipment - Home healthcare environment)
- Internal Verification and Validation: The document states the device was "designed, verified, and validated according to the company's Design Control process and has been subjected to extensive safety and performance testing."
Conclusion from the Submission:
The manufacturer concluded that "bench and non-clinical testing were sufficient to demonstrate that Portable Electro-Stimulation Therapy Device, model: LGT-231 is as safe and effective as the predicate device." The electrical safety, EMC, biocompatibility, software verification and validation, basic unit characteristics, and output specifications information were deemed sufficient to demonstrate substantial equivalence. Given the "nearly identical" nature and "essentially identical technological characteristics" with identical indications for use, the device was found substantially equivalent to the Compex Sport Elite.
§ 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).