(90 days)
The L360 Thigh System is intended to assist knee flexion or extension in adult individuals with muscle weakness related to upper motor neuron disease/injury (e.g., stroke, damage to pathways to the spinal cord). The L360 Thigh System electrically stimulates muscles in the affected leg to provide knee flexion or extension; thus, it also may improve the individual's gait.
The L360 Thigh System may also:
- Facilitate muscle re-education
- Prevent/retard disuse atrophy
- Maintain or increase joint range of motion
- Increase local blood flow
- Provide early post-surgical quadricep and hamstring strengthening
- Improve post-surgical knee stability secondary to quadricep and hamstring strengthening
- Relax muscle spasms
The L360 Thigh System is intended to assist knee flexion or extension in adult individuals with muscle weakness related to upper motor neuron disease/injury (e.g., stroke, damaqe to pathways to the spinal cord). The L360 Thigh System electrically stimulates muscles in the affected leg to provide knee flexion or extension; thus, it also may improve the individual's gait.
The L360 Thigh System consists of:
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- One or two Thigh Functional Stimulation Cuffs (Thigh Cuff) that include surface electrodes.
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- Central External Pulse Generator (EPG). The EPG delivers stimulation to their respective cuffs, and have user interface, including visual, audio, and tactile feedback. The EPG can use motion sensor based algorithm to detect heel events.
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- An optional Control Unit that allows simple wireless remote control of the EPG's while displaying real-time information regarding the system's status.
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- An optional Gait Sensor, which uses a dynamic gait tracking algorithm to detect heel events and wirelessly synchronizes stimulation.
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- A Clinician's Programming System with software, which is used for system programming by a trained clinician during configuration of the system for optimal fitting to the patient.
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- An optional Mobile Application (MAPP) enabling the patients to wirelessly control the EPG(s) and retrieve and monitor their daily activity.
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- A power supply with two USB outputs and a proprietary cable to charge the EPG(s).
This document is a 510(k) Premarket Notification for the Bioness L360 Thigh System, seeking to expand its indications for use. Based on the provided text, the acceptance criteria are primarily demonstrated through a showing of substantial equivalence to existing predicate devices, rather than through a a new clinical study with explicitly defined performance metrics the device needs to meet.
Here's an analysis of the information requested, based on the provided text:
1. A table of acceptance criteria and the reported device performance.
The document does not provide a traditional table of acceptance criteria with specific performance metrics (e.g., accuracy, sensitivity, specificity, or improvement in a clinical outcome that the device must achieve).
Instead, the acceptance criteria for this 510(k) submission are based on demonstrating substantial equivalence to two predicate devices: the Bioness L300 Go System (K190285) and the Bio-Medical Research Ltd. Kneehab XP (K110350). The performance reported is that the device "is performing as intended" and "is substantially equivalent to the predicate devices."
The submission argues that the L360 Thigh System is essentially the "Thigh Standalone configuration" of the L300 Go System, with the only difference being an expansion of indications. Therefore, the performance tests conducted on the L300 Go System are considered applicable.
| Acceptance Criterion (Implicit) | Reported Device Performance (L360 Thigh System / L300 Go System) |
|---|---|
| Technological Characteristics Substantial Equivalence | "The L360 Thigh System, subject of this submission is exactly the same device in all aspect to the Thigh Standalone configuration of its predicate device, the L300 Go System, cleared for marketing under K190285." |
| Expanded Indication Justification | "The only difference between the devices is the expansion of the indication to provide relaxation of muscle spasms and post-surgical muscle strengthening and knee stability. The proposed indication for use is supported by its substantial equivalence to that of the Predicate Device #1, the L300 Go System (K190285) and Predicate Device #2, the Kneehab XP (K110350) with regards to its use as a neuromuscular electronic stimulator (NMES), and additionally supported by scientific literature, the principle of the NMES, and the standard indication for use for Powered Muscle Stimulators classified under 21 CFR 890.5850 (product code: IPF) per FDA Guidance Document for Powered Muscle Stimulator 510(k)s issued on June 9, 1999." |
| Electrical Safety | Meets IEC 60601-1, IEC 60601-2-10, and related standards. Patient Leakage Current: Normal condition: Less than 1.0µA; Single fault condition: 3.0µA. |
| Electromagnetic Compatibility (EMC) | Meets IEC 60601-1-2. |
| Software Verification and Validation | Completed. Meets IEC 62304. |
| Mechanical Durability | Completed. |
| Lifetime Test | Completed. |
| Environmental Conditions | Completed. |
| Biocompatibility | New testing not run as it uses the same materials as the predicate. Predicate underwent Cytotoxicity, Sensitization, Irritation testing in accordance with ISO 10993. |
| Functional Verification and Validation | Completed. |
| Overall Performance & Intended Use | "The conclusions drawn from the performance tests demonstrate that the device is performing as intended, and is substantially equivalent to the predicate devices." |
2. Sample sizes used for the test set and the data provenance (e.g., country of origin of the data, retrospective or prospective).
The document does not describe a new clinical "test set" in the context of typical AI/ML performance evaluation (e.g., a set of patient cases used to evaluate an algorithm's diagnostic accuracy). Instead, it refers to performance tests (electrical, mechanical, functional, software V&V, EMC, biocompatibility) conducted on the L300 Go System (the predicate device). These are engineering and system-level tests, not typically clinical trials involving patient samples.
- Sample Size for Test Set: Not applicable in the context of patient data samples for algorithm performance. The "test set" refers to the device itself being subjected to various engineering and regulatory conformance tests.
- Data Provenance (Country of Origin, Retrospective/Prospective): Not applicable for the type of testing described. The "data" here are results from engineering and biocompatibility tests.
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).
This question is not applicable to the type of device and submission described. This is a functional neuromuscular stimulator, not an AI/ML diagnostic or image analysis device that requires expert ground truth labeling for a test set. The validation relies on engineering and biological safety tests, and a showing of substantial equivalence to predicate devices, supported by scientific literature on the principle of NMES.
4. Adjudication method (e.g., 2+1, 3+1, none) for the test set.
Not applicable. There is no clinical test set requiring expert adjudication for ground truth, as this is not an AI/ML diagnostic device.
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 submission is for a functional electrical stimulation device, not an AI-assisted diagnostic or image interpretation tool. Therefore, an MRMC study comparing human reader performance with or without AI assistance is not relevant to this device or its regulatory pathway.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done.
Not applicable. While the device has software and algorithms for stimulus delivery and gait detection, it is a hardware medical device with specific physical and electrical outputs for therapeutic purposes. Its "performance" is in stimulating muscles as intended, not in autonomously interpreting data or making diagnostic decisions without human involvement in setting up or managing the therapy. The performance tests mentioned (functional, software V&V) implicitly cover standalone algorithm functioning within the device.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.).
For the specific type of device and submission (510(k) for an expanded indication based on substantial equivalence), "ground truth" as typically understood in AI/ML validation (e.g., definitive diagnosis) is not explicitly mentioned or relied upon. The ground truth for proving substantial equivalence relies on:
- Technical Specifications Comparison: Direct comparison of electrical, mechanical, and software characteristics to predicates.
- Engineering Test Results: Pass/fail criteria for electrical safety, EMC, reliability, etc., as per recognized standards (e.g., IEC 60601 series, ISO 14971, ISO 10993).
- Prior Regulatory Clearances: The fact that the predicate devices were previously cleared by the FDA establishes their safety and effectiveness characteristics as a benchmark.
- Scientific Literature and Principle of NMES: Supporting the general safety and effectiveness of Neuromuscular Electrical Stimulation for the stated indications.
8. The sample size for the training set.
Not applicable. This document describes a traditional medical device, not an AI/ML product developed using large training datasets. The "training" for such devices typically refers to the engineering design and development process, informed by established medical principles and device standards.
9. How the ground truth for the training set was established.
Not applicable. As above, there is no AI/ML training set as such. The "ground truth" for the device's design and functionality comes from established engineering principles, international standards, and existing regulatory clearances of similar predicate devices.
§ 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).