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The ReWalk® P6.0 fits to the lower limbs and part ofthe upper body and is intended to enable individuals with spinal cord injury at levels T7 to L5 to perform ambulatory functions in home and community settings with supervision of a specially certified companion in accordance with the user assessment and training certification program. The device is also intended to enable individuals with spinal cord injury at levels T4 to T6 to perform ambulatory functions in rehabilitation institutions in accordance with the user assessment and training certification program. The ReWalk P6.0 is intended for indoor and outdoor use: including standing and walking on level surfaces and mild slopes and ascending and descending stairs and curbs.

The ReWalk® P6.0 Exoskeleton is a prescription device which enables individuals with spinal cord injuries to perform ambulatory functions and composed of an external, powered, motorized frame that fits to the lower limbs and part of the upper body.

The ReWalk is intended to enable certified users with spinal cord injuries at levels T7 to L5 to perform ambulatory functions in in home and community setting accompanied by a certified companion. Additionally, the ReWalk Personal Exoskeleton 6.0 is intended to enable certified users with spinal cord injuries at levels T4 to T6 to perform ambulatory functions in rehabilitation centers accompanied by a certified therapist.

Control of the device is achieved through a wrist-worn User-operated wireless remote controller (RC), tilt sensor and specific body movements. The gait movements are performed by a set of gears and motors at the knee and the hip joints. The ReWalk system includes Remote control (RC) Communicator, Exoskeleton (Inc. Rigid Frames, Waistpack and Straps), Battery charger and Laptop (GUI), and off the shelf crutches. All of the ReWalk components are mandatory, suitable for indoor and outdoor usage. The device is intended for indoor use: including standing and walking on level surfaces and mild slopes, and ascending and descending stairs and curbs for users who are at least 18 years old.

The ReWalk® P6.0 device, an exoskeleton for individuals with spinal cord injury, had its stairs ascend and descend functionality reviewed. The acceptance criteria and the study proving its performance are detailed below:

1. Table of Acceptance Criteria and Reported Device Performance:

2. Sample Size Used for the Test Set and Data Provenance:

• Clinical Performance Test Set (ReWalk P6.0 Active Users Field Survey Study-Stairs Usage):
  • Sample Size: 47 users who used the device to climb stairs (out of 85 recruited subjects).
  • Data Provenance: Retrospective, collected through a survey of actual users in Europe. Data monitored over a period of six (6) years (2015 to May 2022).
• Human Factors Engineering Study Test Set:
  • Sample Size: 11 ReWalk patient subjects and 11 companion subjects.
  • Data Provenance: Prospective, conducted under IRB Approved protocol, according to principles of Good Clinical Practice (GCP).

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts:

This information is not explicitly provided in the document. The studies rely on user performance and self-reported data (field survey), and observed performance (human factors study), rather than expert adjudication of a "ground truth" derived from patient data like in diagnostic device studies.

4. Adjudication Method for the Test Set:

• Clinical Performance Test Set (Field Survey): Adverse events were monitored through ReWalk's Customer Relation Management (CRM) database and reviewed by the company to determine if they were device-related. The "adjudication" was internal to the company, concluding AEs were not device-related but associated with user error or instruction non-compliance.
• Human Factors Engineering Study Test Set: Performance was observed during actual use scenarios and comprehension questions were evaluated. The document doesn't specify an external adjudication panel; the evaluation of successful task completion and correct answers likely involved researchers from the study lead by the company.

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:

This is not applicable. The ReWalk P6.0 is an exoskeleton device, not an AI-assisted diagnostic tool. Therefore, an MRMC comparative effectiveness study involving human readers and AI assistance was not performed.

6. If a Standalone (i.e. algorithm only without human-in-the-loop performance) was done:

This is not applicable. The ReWalk P6.0 is a physical device that requires a human user and a certified companion/therapist for operation. Its performance is inherently human-in-the-loop.

7. The Type of Ground Truth Used:

• For Clinical Performance (Field Survey): The "ground truth" was established by real-world usage data and objective tracking of adverse events. Successful use was measured by the number of stairs climbed, and safety by the incidence and nature of adverse events.
• For Human Factors Study: The "ground truth" was successful completion of predefined tasks (ascending/descending stairs and curbs) by the user/companion, as observed by study personnel, and correct answers to comprehension questions.
• For Bench Testing: The "ground truth" was the physical and functional outcomes meeting predetermined engineering specifications (e.g., mechanical integrity, walking speed verification).

8. The Sample Size for the Training Set:

This information is not provided. The document highlights that the ReWalk P6.0 with stairs functionality is identical in design, materials, and components to a previously cleared version (K200032), except for the enabled stairs function. The prior versions underwent extensive testing, and this submission focuses on validating the added stairs functionality. The "training" for the device itself would be implicitly derived from its design and engineering processes, as well as prior product generations.

9. How the Ground Truth for the Training Set was Established:

Not explicitly detailed for a "training set" in the context of machine learning. For medical devices, the "training set" would relate to the iterative design, development, and testing phases where engineers and designers establish the functional specifications and design goals. Ground truth in this context is established through engineering principles, relevant standards (e.g., IEC 60601 series), and established clinical understanding of safe and effective ambulation assistance.

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The Phoenix orthotically fits to the lower limbs and trunk. The device is intended to enable individuals with spinal cord injury at levels T4 to L5 to perform ambulatory functions in rehabilitation institutions in accordance with the user assessment and training certification program. This device is not intended for sports or stair climbing.

The Phoenix™ is a wearable, powered exoskeleton that assists a trained user to sit, stand, walk, and turn. The Phoenix consists of a pair of motorized leg braces coupled to a torso module, a lithium-ion battery pack, a main controller unit, and a wireless user interface attached to the handle of an assistive device (such as a crutch, walker, or parallel bars), control software, and mobile Android tablet hosting a mobile app. The Phoenix dimensions, such as spine length, torso hip width, femur length, femur bracket, tibia length, tibia bracket, and foot plate length can be adjusted individually. The Phoenix is coupled to the user via soft-good components (i.e. shoulder straps, waist pads, thigh straps, and shin pads), which can be adjusted to accommodate various users' dimensions.

The provided document describes the Phoenix™ powered exoskeleton and its regulatory submission (K183152). It outlines performance data to demonstrate its safety and effectiveness and its substantial equivalence to a predicate device.

Here's a breakdown of the requested information based on the document:

1. Table of Acceptance Criteria and Reported Device Performance

The acceptance criteria are not explicitly stated in a quantitative manner as pass/fail thresholds for specific metrics before the study. Instead, the study objectives and the results achieved are presented as evidence that the device meets its intended purpose. The table below synthesizes the implicit acceptance criteria from the study objectives and the reported performance.

2. Sample size used for the test set and the data provenance

• Sample Size: 40 subjects.
• Data Provenance: The document does not specify the country of origin of the data. It states, "The study was performed in compliance with Good Clinical Practices (GCP) with subjects enrolled in an IRB approved study that were consented for participation according to the intended use of the device, defined inclusion criteria, and defined exclusion criteria..." This implies a prospective clinical study.

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts

The document does not mention the use of experts to establish a "ground truth" for the test set in the traditional sense of diagnostic accuracy studies (e.g., radiologists interpreting images). Instead, the study evaluates the functional performance and safety of the exoskeleton in human subjects. The outcome measures (FIM, WISC-II, 10MWT, 6MWT, TUG Test, Modified Borg) are objective measures or standardized assessments commonly used in rehabilitation, performed by trained clinicians/investigators within the study protocol. The "ground truth" here is the direct, observed performance of the subjects using the device.

4. Adjudication method (e.g., 2+1, 3+1, none) for the test set

The concept of an adjudication method (like 2+1 for conflicting interpretations) is not applicable here as this is a functional performance and safety study, not a diagnostic study requiring interpretation of outcomes by multiple experts. The clinical outcomes were directly measured or observed by the study staff.

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

No, a multi-reader, multi-case (MRMC) comparative effectiveness study was not done. This study is a clinical trial assessing the performance of a medical device (exoskeleton), not an AI-powered diagnostic tool. Therefore, the concept of human readers improving with or without AI assistance is irrelevant to this document.

6. If a standalone (i.e., algorithm only without human-in-the-loop performance) was done

No, a standalone algorithm-only performance study was not done. The Phoenix™ is a physical medical device (exoskeleton) intended for use by individuals with spinal cord injury in rehabilitation settings. Its entire purpose involves human-in-the-loop performance (the user wearing and operating the device under clinician supervision).

7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.)

For this functional performance study, the "ground truth" consists of observed clinical outcomes data and standardized functional assessment scores collected directly from the subjects using the Phoenix™ device in a controlled clinical setting. These include:

• Functional Independence Measure (FIM) scores
• WISC-II scores (likely a typo for WISCI II - Walking Index for Spinal Cord Injury)
• 10 Meter Walk Test (10MWT) results (time, speed)
• 6 Minute Walk Test (6MWT) results (implied distance/FIM score)
• Timed Up-and-Go (TUG) Test results
• Modified Borg Rating of Perceived Exertion scores
• Adverse Event (AE) reporting.

8. The sample size for the training set

The document mentions "training with the device" for the 40 subjects enrolled in the clinical study as part of their 20 sessions. This training is for the actual users (patients) and clinicians to learn how to operate the device, not an algorithm's training data.

The document does not refer to a "training set" in the context of machine learning or AI algorithms. The Phoenix™ is a powered exoskeleton, not an AI diagnostic tool that requires a separate training data set for model development.

9. How the ground truth for the training set was established

As there is no mention of a "training set" for an algorithm in this context, this question is not applicable to the provided document. The device itself is "trained" in terms of its parameters and control mechanisms during its engineering and development phase, but this is distinct from "ground truth for a training set" in AI/ML performance studies.

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