(30 days)
The NESS L300 is intended to provide ankle dorsiflexion in individuals with drop foot following an upper motor neuron injury or disease. During the swing phase of gait, the NESS L300 electrically stimulates muscles in the affected leg to provide dorsiflexion of the foot; thus, it may improve the individual's gait. The NESS L300 may also facilitate muscle re-education, prevent/retard disused atrophy, maintain or increase joint range of motion and increase local blood flow.
This neuroprosthesis device consists of a RF foot sensor (Intelli-sense gait sensor), RF control unit (waist mounted / neck strap / in pocket), and a below the knee orthosis containing electrodes and a RF controlled stimulation unit (RF stim unit).
The Intelli-gait sensor detects "heel off" and "heel contact" events during gait and transmits signals to the RF stim unit. Accordingly, the RF stim unit initiates and pauses the stimulation, activating the foot dorsiflexors to ensure proper foot clearance during the swing phase and proper foot placement during the stance phase.
The NESS L300 comprises of 4 main parts:
- A lower leg orthosis with integrated RF stim unit and electrodes, RF communication, and rechargeable battery,
- A waist mounted (or in-pocket) Control Unit (CU), including a PDA (clinician programmer) interface, RF communication, and AAA rechargeable battery.
- Intelli-sense gait sensor with RF communication and non-rechargeable coin battery.
- Clinician Programmer Handheld computer (PDA)
The provided text describes a Special 510(k) submission for a modification to the NESS L300 device, not a study setting acceptance criteria based on performance data. Therefore, many of the requested details about a study and its methodology are not present in this document.
The document states: "Performance data demonstrates that the modified NESS L300 is as safe and effective as the predicate device." However, it does not provide specific details about this performance data or the study design. A Special 510(k) relies heavily on demonstrating that modifications do not raise new questions of safety or effectiveness compared to a previously cleared device.
Here's a breakdown of what can be extracted from the provided text, and what information is missing:
1. A table of acceptance criteria and the reported device performance
| Acceptance Criteria | Reported Device Performance |
|---|---|
| Implicit: The modified NESS L300 must be "as safe and effective" as the predicate device (NESS L300, K053468). This is the fundamental criterion for a Special 510(k). | The submission claims: "Performance data demonstrates that the modified NESS L300 is as safe and effective as the predicate device." However, no specific performance metrics (e.g., success rates, error rates, improvement in gait parameters) or quantitative data are provided in this summary. |
| Specific to modifications: The minor differences in embedded software, Intelli-Gait (PDA) software, hardware, and accessories must not raise "any new questions of safety or effectiveness." | The submission implies this was met by showing substantial equivalence and receiving FDA clearance. No detailed report of how these specific modifications were tested to ensure they did not introduce new risks or reduce effectiveness is included. |
2. Sample size used for the test set and the data provenance (e.g., country of origin of the data, retrospective or prospective)
- Sample Size: Not specified in the provided text.
- Data Provenance: Not specified in the provided text.
- Retrospective or Prospective: Not specified in the provided text.
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 information is not applicable as the document does not describe a study involving expert-established ground truth for a test set. This is a regulatory submission for a device modification, relying on equivalence to a predicate, not a de novo study with subjective ground truth.
4. Adjudication method (e.g., 2+1, 3+1, none) for the test set
Not applicable. No study with a 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 or imaging device requiring human reader interpretation, so an MRMC study is not relevant here.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
Not applicable. This device is a therapeutic neuromuscular stimulator, not an algorithm, so the concept of "standalone performance" in this context is not relevant as it would be for a diagnostic AI. Its performance is always "human-in-the-loop" in the sense that it's applied to a patient.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc)
Not explicitly defined or discussed. The "ground truth" for this type of device (functional electrical stimulation) would typically be clinical outcomes data related to gait improvement, muscle re-education, range of motion, and blood flow, as described in its indications for use. However, the document does not detail how "performance data" was collected or what specific metrics were measured for the modified device versus the predicate, or what the "ground truth" reference for these outcomes would be.
8. The sample size for the training set
Not applicable. This is not an AI/machine learning device that uses a "training set."
9. How the ground truth for the training set was established
Not applicable. This is not an AI/machine learning device that uses a "training set."
In summary:
This document is a 510(k) summary for a device modification, emphasizing its substantial equivalence to a previously cleared predicate device. It states that "performance data demonstrates that the modified NESS L300 is as safe and effective as the predicate device," which is the core acceptance criterion for this type of submission. However, it does not provide any specific details about the nature, methodology, sample size, or results of that performance data. The document essentially asserts that such data exists and supported the claim of equivalence, rather than presenting the study itself.
§ 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).