(265 days)
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:
| Test Name | Acceptance Criteria (Implied from description) | Reported Device Performance |
|---|---|---|
| Stairs Usage Mechanical Loading Test | Device has sufficient mechanical integrity for safe and effective use under worst-case conditions. | PASS |
| Walking Speed Verification | Maximize the walking speed of the ReWalk P6.0 device with its maximal configuration. | PASS (Successfully measured maximal walking speed) |
| Stairs Validation | Device performs as intended when used by certified users for ascending and descending stairs. | PASS (Device performs as intended) |
| Curbs Validation | Device performs as intended when used by certified users for ascending and descending curbs. | PASS (Device performs as intended) |
| Outdoor Validation | Device performs as intended when used by certified users for ascending and descending stairs and curbs outdoors. | PASS (Device performs as intended) |
| Clinical Safety (Adverse Events) | Low incidence of device-related adverse events, particularly those related to stairs usage. | 3 stairs-related AEs recorded over 6 years; concluded not device-related. |
| Clinical Effectiveness (Stairs Use) | Ability to safely and effectively ascend/descend stairs in home/community settings. | Mean 383 stairs per user (cumulatively 18,038 stairs for all users) over 26 months average use. Demonstrated safe and effective. |
| Human Factors (Usability) | Users (patients and companions) can safely and effectively interact with the device's stairs feature. | 99% successful completion of test tasks; vast majority answered knowledge questions correctly; no adverse events. |
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.
§ 890.3480 Powered lower extremity exoskeleton.
(a)
Identification. A powered lower extremity exoskeleton is a prescription device that is composed of an external, powered, motorized orthosis that is placed over a person's paralyzed or weakened limbs for medical purposes.(b)
Classification. Class II (special controls). The special controls for this device are:(1) Elements of the device materials that may contact the patient must be demonstrated to be biocompatible.
(2) Appropriate analysis/testing must validate electromagnetic compatibility/interference (EMC/EMI), electrical safety, thermal safety, mechanical safety, battery performance and safety, and wireless performance, if applicable.
(3) Appropriate software verification, validation, and hazard analysis must be performed.
(4) Design characteristics must ensure geometry and materials composition are consistent with intended use.
(5) Non-clinical performance testing must demonstrate that the device performs as intended under anticipated conditions of use. Performance testing must include:
(i) Mechanical bench testing (including durability testing) to demonstrate that the device will withstand forces, conditions, and environments encountered during use;
(ii) Simulated use testing (
i.e., cyclic loading testing) to demonstrate performance of device commands and safeguard under worst case conditions and after durability testing;(iii) Verification and validation of manual override controls are necessary, if present;
(iv) The accuracy of device features and safeguards; and
(v) Device functionality in terms of flame retardant materials, liquid/particle ingress prevention, sensor and actuator performance, and motor performance.
(6) Clinical testing must demonstrate a reasonable assurance of safe and effective use and capture any adverse events observed during clinical use when used under the proposed conditions of use, which must include considerations for:
(i) Level of supervision necessary, and
(ii) Environment of use (
e.g., indoors and/or outdoors) including obstacles and terrain representative of the intended use environment.(7) A training program must be included with sufficient educational elements so that upon completion of training program, the clinician, user, and companion can:
(i) Identify the safe environments for device use,
(ii) Use all safety features of device, and
(iii) Operate the device in simulated or actual use environments representative of indicated environments and use.
(8) Labeling for the Physician and User must include the following:
(i) Appropriate instructions, warning, cautions, limitations, and information related to the necessary safeguards of the device, including warning against activities and environments that may put the user at greater risk.
(ii) Specific instructions and the clinical training needed for the safe use of the device, which includes:
(A) Instructions on assembling the device in all available configurations;
(B) Instructions on fitting the patient;
(C) Instructions and explanations of all available programs and how to program the device;
(D) Instructions and explanation of all controls, input, and outputs;
(E) Instructions on all available modes or states of the device;
(F) Instructions on all safety features of the device; and
(G) Instructions for properly maintaining the device.
(iii) Information on the patient population for which the device has been demonstrated to have a reasonable assurance of safety and effectiveness.
(iv) Pertinent non-clinical testing information (
e.g., EMC, battery longevity).(v) A detailed summary of the clinical testing including:
(A) Adverse events encountered under use conditions,
(B) Summary of study outcomes and endpoints, and
(C) Information pertinent to use of the device including the conditions under which the device was studied (
e.g., level of supervision or assistance, and environment of use (e.g., indoors and/or outdoors) including obstacles and terrain).