(463 days)
The MStim Drop LGT-233 is intended to provide ankle dorsiflexion in individuals who have a dropped foot as a consequence of upper motor neuron injury. The device electrically stimulates muscles in the affected leg to provide ankle dorsiflexion of the foot and/or knee flexion or extension; thus, it also may improve the individual's gait. The MStim Drop LGT-233 may also:
·Prevent/retard disuse atrophy
· Maintain or increase joint range of motion
•Increase local blood flow
The MStim Drop LGT 233 is a wearable foot drop device, which is mainly consist s of stimulator main unit, electrode lead wire, electrodes pad, leg bandage and battery charger. The stimulator main unit can be charge by the battery charger.
The device can control the out stimulation and treatment time setting by APP application provided by the manufacturer, and it can trigger and control the pulse stimulation on and off by detecting the swing phase of gait during walking. The device was design to use FES (Functional Electrical Stimulation) to treat and improve the patient s foot drop and help to improve walking ability. It has two modes: Training mode, Walk mode. Training mode is suitable for muscle training when the patient is seated or lying down (patient lacking active training), which can promote muscle recover, prevent muscle atrophy, improve joint range of motion, and increase local blood flow. Walk mode is walking with the electrical stimulation.
The MStim Drop Model: LGT-233 is an external functional neuromuscular stimulator intended to provide ankle dorsiflexion in individuals with dropped foot due to upper motor neuron injury. It electrically stimulates muscles to improve gait and may also prevent/retard disuse atrophy, maintain or increase joint range of motion, and increase local blood flow.
Here's an analysis of the provided information regarding acceptance criteria and studies:
1. Table of Acceptance Criteria and Reported Device Performance
The provided document (a 510(k) summary) does not explicitly state "acceptance criteria" in a quantitative, measurable sense for clinical performance. Instead, it demonstrates substantial equivalence to predicate devices through a comparison of technical specifications and an assertion of compliance with various electrical safety and biocompatibility standards. The reported device performance is largely a direct comparison of its technical specifications to those of the predicate devices.
Here's a table summarizing the comparison of key technical elements. "SE" in the remark column indicates "Substantially Equivalent” as claimed by the manufacturer. "Minor difference" remarks are explained in the "Comparison in Detail(s)" section of the document.
| Elements of Comparison | Subject Device (MStim Drop Model: LGT-233) | Predicate Device I (L300 Go System, K162407) | Predicate Device II (MyGait Stimulation System, K141812) | Remark |
|---|---|---|---|---|
| Indications for Use | Provides ankle dorsiflexion, improves gait, prevents atrophy, maintains/increases ROM, increases local blood flow. | Provides ankle dorsiflexion, assists knee flexion/extension, improves gait. | Provides ankle dorsiflexion and knee flexion/extension, improves gait, prevents/retards atrophy, facilitates muscle reeducation, maintains/improves ROM, promotes local blood circulation. | SE |
| Apply parts | Leg | Leg and foot | Leg and foot | SE |
| Power Sources | Adapter supply: AC 100~240V, Battery: 3.7V, 1200mAh, lithium. | Battery operated | Battery operated | Minor difference (Note 1) |
| Indicator display | LED and APP | -- | -- | Minor difference (Note 1) |
| Method of Line Current Isolation | Battery operated | -- | Medical Class II Power Adapter | SE |
| Number of Modes for Micro current stimulation | 2 (Training mode, Walk mode) | Two modes: Biphasic Symmetric and Biphasic Asymmetric. | 2 | SE |
| Number of Channels for Micro current stimulation | 1 | 1-2 channels depending on cuff. | 2 | SE |
| Synchronous or Alternating | Not applicable – single channel device | Alternating | Synchronous or alternating | SE |
| Regulated Current or Regulated Voltage | Regulated Voltage | Current | Regulated Current | SE (Note 2 refers to Timer Range, not this) |
| Software/Firmware/Microprocessor control | Yes | Yes | Yes | SE |
| Automatic Overload Trip | Yes | Yes | Yes | SE |
| Automatic No-load Trip | Yes | Yes | Yes | SE |
| Automatic Shut Off | Yes | Yes | No | SE |
| Patient Override Control | Yes | Yes | Yes (ON/OFF Button) | SE |
| Indicator Display (Status, Low Battery, Voltage/Current Level) | Yes (On/Off Status, Low Battery); No (Voltage/Current Level) | Yes for all | Yes for all | SE (Remark for each, although Voltage/Current is 'No' for subject device) |
| Timer Range | 1min-60min, stepping 1min | Max stimulation duration (clinician selectable) Training mode: 5-60 minutes | 5 to 120min in steps of 5 min | Minor difference (Note 2) |
| Console weight | 60g (main unit) | Control Unit: 60g, EPG: 60g, Lower leg FSC:150g, Thigh cuff: 300g, Foot Sensor: 25g | 78g | SE |
| Housing Materials and Construction | ABS | Mixed (Polycarbonate + ABS, Biocompatible fabric, POM Hi, TPU) | ABS | SE |
| Waveform | Biphasic square | Biphasic Symmetrical | Biphasic | SE |
| Shape | Rectangular | Rectangular | Rectangular | SE |
| Maximum Output Voltage (+/- 10%) | 50V @ 500Ω, 90V @ 1KΩ, 120V @ 2KΩ, 130V @ 10KΩ | Lower leg: 50V@500Ω, 130V@2KΩ, 130V@10KΩ; Thigh: 50V@500Ω, 130V@2KΩ, 130V@10KΩ | 45V @ 500Ω, 90V @ 1KΩ, 120V@2KΩ, n/a @10KΩ | Minor difference (Note 3) |
| Maximum output Current | 100mA @ 500Ω, 90mA @ 1KΩ, 60mA @ 2KΩ, 13mA @ 10KΩ | Lower leg: 100mA@500Ω, 65mA@2KΩ, 13mA@10KΩ; Thigh: 100mA@500Ω, 65mA@2KΩ, 13mA@10KΩ | 90mA @ 500Ω, 90mA @ 1KΩ, 60mA@2KΩ, n/a @10KΩ | Minor difference (Note 3) |
| Frequency range | 10~80Hz | 10, 15, 20, 25, 30, 35, 40, 45 Hz | 10 to 80Hz in 1Hz steps | Minor difference (Note 4) |
| Pulse width range | 50~500µs | 100, 150, 200, 250, 300µs (each: positive and phase) | Symmetrical: 50 | Minor difference (Note 4) |
| Pulse duration | 50~500µs | Positive phase: 100, 150, 200, 250, 300 µs; Negative phase: 100, 150, 200, 250, 300 µs | Symmetrical: 50 | Minor difference (Note 4) |
| Net Charge | 0uC @ 500Ω | 0µC using inverted balanced phases | 0µC @ 500Ω Balanced pulses | SE |
| Maximum Current Density | Train mode: 0.532mA/cm²@500Ω, Walk mode: 0.53mA/cm²@500Ω | Lower leg (small cuff): 1.63 mA/cm² (rms), Lower leg (regular cuff): 1.04 mA/cm² (rms), Thigh: 0.23 mA/cm² (rms) | 1.51 mA/cm² @500Ω | Minor difference (Note 5) |
| Maximum Power Density | Train mode: 5.66 mW/cm²@500Ω, Walk mode: 5.62 mW/cm²@500Ω | Lower leg (small cuff): 13.4 mW/cm², Lower leg (regular cuff): 8.5 mW/cm², Thigh: 1.9 mW/cm² | 0.024 W/cm² | Minor difference (Note 5) |
| ON time | For Train mode: 2~40s, For Walk mode: N/A | Training mode: 4-20 sec, Gait mode: 1-10 sec | 1 to 4 sec in 0.1sec steps | Minor difference (Note 6) |
| OFF time | For Train mode: 2.0~60.0s, For Walk mode: N/A (swing phase detecting) | Training mode: 4-20 sec, Gait mode: not limited (swing phase detecting) | 1 to 30 sec in 1sec steps | Minor difference (Note 6) |
| Contraction and Relaxation time | Adjustable | -- | Adjustable | SE |
| Environment for operating | Temperature: 5 to 40°C; Rel. humidity: ≤80% | -- | No specific values listed in comparison table. | SE |
| Environment for storage and transport | Temperature: -20 to 55°C; Rel. humidity: ≤93% | -- | No specific values listed in comparison table. | SE |
| Biocompatibility | Compliant with ISO10993-5, -10, -12 | No specific standards listed in comparison table. | No specific standards listed in comparison table. | SE |
| Electrical Safety, EMC | Compliant with IEC 60601-1, -2-10, -1-2, -1-11, IEC 62133-2 | IEC 60601-1, IEC 60601-1-2, IEC 60601-2-10, FCC part 15 subpart C and B1 | IEC 60601-1:2005+A1:2012; IEC 60601-1-11:2010; IEC 60601-2-10:2012; IEC 60601-1-2:2007 | SE |
2. Sample size used for the test set and the data provenance (e.g., country of origin of the data, retrospective or prospective)
The document primarily relies on bench testing for safety and performance evaluation against recognized standards (IEC, ANSI, ISO). There is no mention of a human clinical study or "test set" in the context of clinical performance data used for this 510(k) submission. Therefore, sample size and data provenance for a clinical test set are not applicable here.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts (e.g., radiologist with 10 years of experience)
Not applicable, as no clinical test set for performance involving ground truth established by experts is described for this submission. The submission focuses on substantial equivalence based on technical specifications and compliance with safety standards.
4. Adjudication method (e.g., 2+1, 3+1, none) for the test set
Not applicable, as no clinical test set requiring adjudication is described.
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 an electrical stimulator, not an AI-powered diagnostic tool requiring reader performance evaluation.
6. If a standalone (i.e., algorithm only without human-in-the-loop performance) was done
Not applicable. This is not an algorithm-only device.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.)
For the safety and performance evaluation reported, the "ground truth" used is compliance with various international standards for medical electrical equipment (e.g., IEC 60601 series), battery safety (IEC 62133-2), and biological evaluation (ISO 10993 series). These standards define acceptable limits and testing methodologies for device characteristics. No clinical outcomes data or expert consensus on clinical effectiveness is presented as "ground truth" in this submission.
8. The sample size for the training set
Not applicable. This device does not appear to incorporate machine learning algorithms that require a "training set" in the context of AI model development.
9. How the ground truth for the training set was established
Not applicable, as no training set for AI model development is mentioned.
§ 882.5810 External functional neuromuscular stimulator.
(a)
Identification. An external functional neuromuscular stimulator is an electrical stimulator that uses external electrodes for stimulating muscles in the leg and ankle of partially paralyzed patients (e.g., after stroke) to provide flexion of the foot and thus improve the patient's gait.(b)
Classification. Class II (performance standards).