(464 days)
The Ekso™ (version 1.1) and Ekso GT™ (version 1.2) are intended to perform ambulatory functions in rehabilitation institutions under the supervision of a trained physical therapist for the following population with upper extremity motor function of at least 4/5 in both arms:
- Individuals with hemiplegia due to stroke
- Individuals with spinal cord injuries at levels T4 to L5
- Individuals with spinal cord injuries at levels of C7 to T3 (ASIA D).
The therapist must complete a training program prior to use of the device. The devices are not intended for sports or stair climbing.
The Ekso is a powered motorized orthosis. It consists of a fitted metal brace that supports the legs, feet, and torso. It is worn via straps on the body, legs, and feet. Battery powered motors drive knee and hip joints. It has an integrated solid torso containing the computer and power supply. It has a hand-held user interface to specify settings and initiate steps. The Ekso is used with a cane, crutch, or walker.
The provided text describes the Ekso™ (version 1.1) and Ekso GT™ (version 1.2) powered lower extremity exoskeletons and their substantial equivalence to a predicate device (ReWalk™). The text primarily focuses on comparing the characteristics of the Ekso device with its predicate and detailing clinical studies to support its safety and performance for its stated indications for use.
Here's an analysis of the requested information based on the provided text:
1. A table of acceptance criteria and the reported device performance
The document does not explicitly state acceptance criteria in a quantitative, pass/fail format typical of certain medical device pre-market notifications. Instead, it presents a comparison with a predicate device and then details clinical study results to demonstrate safety and performance. The "acceptance criteria" can be inferred from the "Significant Differences" column in Table 1 and the "Results" section of the clinical studies, demonstrating that the device performs comparably or acceptably for its intended use without raising new safety or efficacy concerns.
Inferred Acceptance Criteria & Reported Performance (from comparison and clinical studies):
| Acceptance Criteria (Inferred from Predicate Comparison & Clinical Studies) | Reported Device Performance (Ekso™) |
|---|---|
| Safety: | |
| - No additional safety or efficacy concerns compared to predicate for expanded indications (stroke, higher SCI injury range). | - Clinical data evaluated safety for higher level SCI and stroke patients, limiting use to those with adequate upper extremity motor strength (at least 4/5 in both arms). |
| - Safety during ambulation and sitting/standing transitions. | - Clinical data supports safe use for ambulation and sitting/standing transitions despite larger range of motion. |
| - Failsafe feature allows user to recover during a fault. | - In event of power failure, knees become locked and hips free, allowing user to remain standing and recover. |
| - No serious adverse events (SAEs) such as falls or injuries reported in clinical studies. | - Study 1: No falls reported. 1 subject with blisters, 5 with pain (self-limiting). |
- Study 2: 1 subject had 2 falls without injury. No injuries reported.
- Study 3: No falls or other adverse events reported.
- Study 4: No falls or other adverse events reported.
- Study 5: No falls or other adverse events reported. |
| Device Characteristics & Performance: | |
| - Similar indications for use but potentially expanded to include stroke patients and a wider range of SCI levels (C7-T3 ASIA D). | - Intended for hemiplegia due to stroke, SCI T4-L5, and SCI C7-T3 (ASIA D), with upper extremity motor function of at least 4/5 in both arms. Deemed "Similar" without additional safety concerns. |
| - Mobility Aid: Support for various mobility aids (walker, crutches, cane). | - Utilizes walker, crutches, cane. Deemed "Similar" with no additional safety or efficacy concerns for added options. |
| - Ability to sit, stand, walk, and turn. | - Can sit, stand, walk, and turn (same as predicate). |
| - Walking Speed: Comparable to predicate. | - ~2 km/hr (same as predicate). |
| - Grade of Inclination: Suitable for intended flat environments. | - 1.15 deg (lower than predicate's 5 deg, but consistent with indoor use, so no additional safety/efficacy concerns). |
| - Type of Surface: Suitable for smooth, cement, carpet. | - Smooth, cement, carpet. Not walking on grass presents no additional safety concerns as intended for indoor use. |
| - Patient Population: Adaptable to intended patient population. | - Adults over 18 with hemiplegia due to stroke, SCI T4-L5, and SCI C7-L5 ASIA D. Evaluated for these differences. |
| - Control Method: Efficient and safe for initiating steps. | - Handheld interface for PT; weight shift to initiate steps. Deemed "Similar" with no additional safety or efficacy concerns. |
| - Range of Motion: Allows for comfortable and functional movement. | - Hips: 135° flexion to 20° extension, Knees: 130° flexion to 0° extension, Ankles: 10° flexion to 10° extension (larger than predicate, supporting sitting/standing transitions and comfort). |
| - Weight: Lighter is preferable (no additional safety/efficacy concerns). | - 50 lbs (23 kg) - lighter than predicate, no safety/efficacy concerns. |
| - Battery: Provides necessary power and operates safely. | - Rechargeable lithium ion batteries (48.1V, 30A peak current, 1 hr continuous usage). Tested per specification, no additional safety/efficacy concerns. |
| - Battery Charge Time: Manageable for clinical use. | - 1 hour (shorter than predicate, allows for swapping, no additional safety/efficacy concerns). |
| - Expected Useable Life: Reasonable for medical device. | - 4 years (shorter than predicate, but within acceptable limits, no additional safety/efficacy concerns). |
| - Training Program and Certification: Ensures safe operation by trained professionals. | - Yes, extensive two-phase training and certification program for therapists (Level 1: basic, Level 2: advanced/independent). |
| - Clinical Effectiveness: Improvement in ambulation parameters (10MWT, 6MWT, FIM scores). | - Study 1 (SCI): Mean 10MWT improved (66s pre to 40s post). - Study 2 (SCI): Mean 10MWT improved (160s pre to 78s post), Mean 6MWT improved (82m pre to 152m post).
- Study 3 (Stroke): Mean 10MWT improved (150s pre to 79s post), Mean 6MWT improved (40m pre to 88m post), Mean FIM scores improved (24 pre to 49 post).
- Study 4 (Stroke): Mean FIM scores improved (25 pre to 51 post).
- Study 5 (Stroke): Mean 10MWT improved (76s pre to 37s post), Mean 6MWT improved (48m pre to 83m post). |
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 lists five clinical studies:
- Study 1 - SCI:
- Sample Size: 44 subjects (35 ASIA A-B, 21 ASIA C-D, some overlap likely given the numbers provided - total patients 44 in text).
- Data Provenance: Multi-center, prospective, open-label, non-comparative, non-randomized. Conducted at 6 sites from 5 countries.
- Study 2 - SCI:
- Sample Size: 12 subjects (9 ASIA A, 3 ASIA B).
- Data Provenance: Single center, open-label, non-comparative, non-randomized, prospective.
- Study 3 - Stroke:
- Sample Size: 54 subjects.
- Data Provenance: Single center, exploratory retrospective analysis.
- Study 4 - Stroke:
- Sample Size: 54 subjects.
- Data Provenance: Single center, open-label, non-comparative, non-randomized, prospective.
- Study 5 - Stroke:
- Sample Size: 8 subjects (6 in Arm 1, 2 in Arm 2).
- Data Provenance: Single center, prospective, two-arm study.
The countries of origin for the studies are only explicitly stated for "Study 1 - SCI" (6 sites from 5 countries).
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 provided in the document. The clinical studies report objective measures (e.g., 10MWT, 6MWT, FIM scores, heart rate, blood pressure) and adverse events, which would typically be recorded by trained clinical staff like physical therapists and physicians. The establishment of "ground truth" in terms of expert consensus on diagnosis or a gold standard interpretation is not applicable here as the studies assess functional outcomes and safety for device use. The document does state that the device is used "under the supervision of a trained physical therapist" and mentions a "certification program" for therapists.
4. Adjudication method (e.g. 2+1, 3+1, none) for the test set
This information is not provided in the document. The clinical studies describe objective measurements of functional performance and adverse event reporting. There is no mention of an adjudication process by multiple experts for subjective outcomes or interpretations.
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 MRMC comparative effectiveness study was done or mentioned. This type of study (MRMC) is typically relevant for diagnostic imaging AI devices where human readers (e.g., radiologists) interpret images with and without AI assistance. The Ekso device is a physical rehabilitation exoskeleton, not an AI diagnostic tool.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
The Ekso device is an exoskeleton designed for use by patients under the supervision of a trained physical therapist. Its core function involves mechanical assistance for ambulation with human interaction and supervision. Therefore, a "standalone algorithm only" performance study is not applicable or relevant for this type of device. The performance is inherently human-in-the-loop.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc)
The "ground truth" in these studies consists of clinical outcomes data and safety event reporting. This includes:
- Functional performance metrics:
- 10-Meter Walk Test (10MWT) time (seconds)
- 6-Minute Walk Test (6MWT) distance (meters)
- Functional Independence Measure (FIM) scores
- Physiological measurements: Heart rate, blood pressure.
- Adverse events: Blisters, pain, falls (with or without injury).
These are direct measurements of patient response and device safety, not an "expert consensus" on a diagnosis or a "pathology" result.
8. The sample size for the training set
The document does not provide a specific sample size for a "training set" in the context of machine learning or AI. The clinical studies mentioned are for evaluating the device's performance and safety, not for training an algorithm within the device. The "training" described in the document refers to the program for physical therapists to learn how to operate the Ekso device.
9. How the ground truth for the training set was established
Since there is no "training set" in the context of machine learning described for the device itself, this question is not applicable. The "ground truth" for the therapist training is established through competency demonstration as assessed by the "Ekso Bionics Clinical Training Team" against defined operational and safety criteria.
§ 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).