Indego

• K Number: K152416
• Device Name: Indego
• Manufacturer: PARKER HANNIFIN CORPORATION
• Date Cleared: 2016-02-26 ( 184 days)
• Product Code: PHL
• Regulation Number: 890.3480
• Type: Traditional
• Panel: NE
• Reference & Predicate Devices: N/A

Intended Use

The Indego® orthotically fits to the lower limbs and the trunk; the device is intended to enable individuals with spinal cord injury at levels T7 to L5 to perform ambulatory functions with supervision of a specially trained 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 Indego is not intended for sports or stair climbing.

Device Description

Parker Hannifin's Indego® device is a wearable powered exoskeleton that actively assists individuals to stand and walk. Unique in design, the Indego consists of five (5) snap-together components (the lumbar/hip section, right and left upper leg sections, and right and left lower leg sections) weighing 26 pounds total. The hip component houses a rechargeable battery pack, central processor, and Bluetooth module, while each upper leg component houses two motors as well as embedded sensors and controllers.

On-board microprocessors receive signals from integrated sensors which provide information on the user's posture and tilt. This allows the device to function in a manner similar to the Segway personal mobility device, which is controlled by the user's tilt. A user similarly controls the Indego by means of postural changes (e.g., to walk forward, the user just leans forward). The technology of the design links the low weight and low profile to battery technology (smaller size), motors (smaller and more powerful), and micro controllers. Visual cues from LED lights on the hip unit and vibratory feedback inform both the therapist and patient of the status and mode of operation.

The Indego controls are self-contained, with crutches or a walker used solely for stability. Users can perform sit-to-stand and stand-to-sit transitions and walk along even or uneven terrain up to about five degree (5°) grades. Taller torso "wings" are provided to support users who may need additional trunk support while walking. A physical therapist can configure, operate, and monitor the device during therapy and training to make adjustments as needed. This is achieved through the support of a wireless application that will run on mobile/wifi connected smart devices such as an iPod or iPhone. Through the use of a Bluetooth connection, the Indego device's mode of operational parameters such as gait speed and step length/height, will be able to be changed or modified in real time. The device can be utilized in multiple indoor and outdoor locations within a rehabilitation setting or personal setting.

AI/ML Overview

The provided text describes the regulatory submission for the Indego exoskeleton device. It details the device, its intended use, and a comparison to a predicate device (ReWalk). The filing includes non-clinical and clinical performance data to demonstrate safety and effectiveness.

Here's the breakdown of the acceptance criteria and study information:

Acceptance Criteria and Device Performance

Criteria	Acceptance Criteria	Reported Device Performance
Primary Safety & Effectiveness Criterion:	Device is both safe and effective for the intended use for patients with SCI who are non-ambulatory or poorly ambulatory to stand up and walk under a variety of conditions.	The clinical study concluded that the Indego device is safe and effective for its intended use. Adverse events reported were minor (bruising, redness, abrasion, swelling), primarily related to improper fitting or padding, with no unanticipated adverse events. The study demonstrated the ability of subjects to stand up and walk, as detailed in the performance metrics below.
Primary Effectiveness Criterion (Walking Speed):	The average walking speed for persons with SCI using the Indego device with stability aid will be equal to or greater than 0.31 m/s for indoor surfaces.	Walking speed was captured during the study through a Ten Meter Walk Test (10MWT) on indoor surfaces, resulting in speeds of 0.38 m/s ± 0.08 m/s at the completion of the study. This meets the criterion.
Ability to Perform Transitional Motions (TUG Test):	Not explicitly stated as an acceptance criterion with a specific threshold, but the study aimed to measure this ability.	Of the 40 enrolled subjects, 39 were able to complete the Timed Up-and-Go (TUG) Test with minimal contact assistance (FIM score of 4), and one (1) subject was able to complete with moderate contact assistance (FIM score of 3). This indicates successful performance of transitional motions.
Sustained Walking Capacity:	Not explicitly stated as an acceptance criterion.	38 (thirty-eight) subjects were able to complete a single-session walk of 600 meters in length.
Level of Assistance (WISC-II and FIM scores):	Not explicitly stated as an acceptance criterion with specific thresholds, but measured to assess task-specific assistance needed.	The WISC-II scores for all subjects averaged mean scores of 6 ± 1.0 (midpoint) and 7 ± 1.6 (final assessment). FIM scores, as noted above for the TUG test, support that all subjects were capable of managing all tested terrains and scenarios, including indoors/outdoors, various surfaces (tile, concrete, asphalt, grass, carpet), and navigating obstacles (sidewalks, ramps, curb cutouts, elevators, automatic doors, latch doors).
Perceived Exertion (Borg Scale):	Not explicitly stated as an acceptance criterion with a specific threshold.	The averaged results of the Borg Rating of Perceived Exertion for indoor level ground walking at the end of their sessions was 10, which corresponds to an exertion level between "very light exercise" and "light exercise". This suggests the device allows for ambulation with reasonable perceived effort.
Absence of Unanticipated Adverse Events:	Absence of any Unanticipated Adverse Events (UAE).	There were no Unanticipated Adverse Events (UAE) reported.
Non-Clinical Performance Data:	Meet all requirements for design characteristics, non-clinical performance testing, EMC/EMI testing, and electrical safety testing to confirm that the output meets the design inputs and specifications for the device.	Indego device passed Maximum Torque Testing, Cleaning Chemical Compatibility Testing, Component Life Cycle Testing, Durability Testing, Battery Life Cycle Testing, Storage and Transport Testing, Software verification and validation testing, Electrical safety testing (ANSI/AAMI ES60601-1), and Electromagnetic compatibility testing (IEC 60601-1-2).

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Study Details:

1. Sample size used for the test set and the data provenance:

   • Sample Size: 40 subjects.
   • Data Provenance: The document does not explicitly state the country of origin but implies a prospective clinical study ("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..."). This suggests a controlled clinical trial setting.

2. 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 medical image analysis or diagnostic studies. Instead, the clinical study involved subjects using the device and their performance (walking speed, TUG test, level of assistance, perceived exertion) being measured directly. The "truth" here is the objective measurement of their functional abilities while using the device.

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

   • Not applicable in the context of this functional performance study. The data collected (e.g., walking speed, FIM scores, TUG test results) are objective measurements or standardized assessment scores, not subjective interpretations requiring adjudication.

4. 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 performed. This type of study typically applies to diagnostic or screening devices where human readers interpret medical images or data. The Indego is a powered exoskeleton for ambulation; its effectiveness is measured directly through functional performance metrics of the user.

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

   • The device, by its nature, inherently involves a human-in-the-loop. It is a wearable exoskeleton designed to assist individuals with spinal cord injury in performing ambulatory functions. Therefore, a standalone (algorithm only) performance assessment, independent of human interaction, is not relevant or applicable for this device. The software verification and validation were performed as part of non-clinical testing, but this is distinct from measuring "standalone performance" of a diagnostic algorithm.

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

   • The "ground truth" in this context is based on objective functional performance data using standardized clinical assessment tools (e.g., Ten Meter Walk Test, Timed Up-and-Go Test, WISC-II, FIM scores, Borg Rating of Perceived Exertion) and direct observation of subjects' abilities while using the device in a controlled clinical study environment.

7. The sample size for the training set:

   • The document does not explicitly mention a "training set" in the machine learning sense for the device's algorithms. The device's internal microprocessors receive signals from integrated sensors and function based on the user's posture and tilt (similar to a Segway). The development of these control algorithms would have involved engineering design, testing, and potentially iterative refinement, but the document does not specify a distinct "training set" of data in the manner of AI/ML models.

8. How the ground truth for the training set was established:

   • Given that a "training set" (as understood in machine learning) is not explicitly described, the method for establishing its "ground truth" is not detailed. The device likely relies on engineering principles and biomechanical models for its control algorithms, validated through non-clinical and clinical testing, rather than an AI model trained on a large dataset with established ground truth labels common in areas like image recognition. The "ground truth" for its functional performance is established through the clinical study mentioned above.

Regulation Number and Section

§ 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).