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510(k) Data Aggregation
(107 days)
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The Alter-G G-Trainer is indicated for use in the following conditions:
Aerobic conditioning Weight control and reduction Sport specific conditioning programs Gait training in neurologic patients Strengthening and conditioning in older patients Rehabilitation following injury or surgery of the lower extremity Rehabilitation following injury or surgery of the hip, knee, ankle or foot. Rehabilitation after total joint replacement
The G-Trainer is designed to provide an adjustable weight support while the user exercises on the incorporated treadmill. The G-trainer is comprised of a standard exercise treadmill with an integrated unweighting component that can effectively reduce the body weight of an individual while they exercise. A bag that looks much like a small tent is placed over the running surface of the treadmill and sealed in such a manner that an electric blower can inflate the bag. The subject wears a special pair of shorts that zip into the top and center of the bag much like the skirt used on a kayak. The subject zips into the bag and stands on the surface of the treadmill. Using a touch screen control panel, the subject is able to increase or decrease the pressure in the bag. The pressure in the bag provides weight support for the user. By this method. the effective weight of the subject on the treadmill surface can be precisely controlled while they exercise.
The G-Trainer is comprised of a base frame, a treadmill, an upper support frame, the inflatable bag, a pressure source and regulation system, control electronics and a control console.
The provided text describes the G-Trainer, a treadmill unweighing system, and its clinical validation. However, it does not contain typical "acceptance criteria" in the format of specific thresholds for metrics like sensitivity, specificity, accuracy, or F1-score, which are common for AI-driven diagnostic devices. Instead, the document focuses on demonstrating the device's functional equivalence to predicate devices and its safety and effectiveness through various studies.
Here's an analysis based on the information provided, framed to address your requested points where applicable:
1. Table of Acceptance Criteria and Reported Device Performance
As mentioned, explicit "acceptance criteria" with numerical thresholds are not present in this document. Instead, the performance is described qualitatively in relation to its intended use and comparison to predicate devices. The primary functional claim demonstrated is the ability to accurately adjust effective body weight.
| Acceptance Criteria (Inferred) | Reported Device Performance |
|---|---|
| Accuracy in adjusting effective body weight | "highly accurate in adjusting the effective body weight of an exercising subjects." "A highly correlated, linear relationship between %body weight and measured body weight could be demonstrated." "The results of this study indicate the G-Trainer to be as effective as the predicate devices in adjusting effective body weight." (Non-Clinical Performance Data) "A linear relationship was found between ground reaction force and % body weight reduction." (Third VA study) "Reduction in ground reaction force showed good correlation with the reduction in body weight." (First UCSD study) "Ground reaction force was observed to decrease linearly with increasing weight support." (University of Colorado study) |
| Safety for use (e.g., cardiovascular response, adverse events) | "Changes in heart rate and blood pressure were of the same magnitude as the change seen when moving from a standing to a supine position." (First VA study) "No significant difference in cardiovascular response was seen between full body weight and unweighted (75% reduction) exercise. The authors concluded that walking with air pressure support appeared to be safe for individuals with stable cardiovascular conditions." (Second VA study) "The authors concluded that neither cardiovascular parameters nor gait characteristics change significantly with lower body positive pressure exercise. They suggest that lower body positive pressure exercise is a potentially new and safe rehabilitation tool..." (Second UCSD study) "The clinic reported no adverse incidents while using the G-Trainer and concluded it to be a safe and effective tool in the clinical setting." (Device Design Validation Trial) "No adverse events were reported in more than 500 individuals cited in these studies, testament to the safety of the G-Trainer..." (Clinical Performance Data Summary) |
| Effectiveness in rehabilitation/gait mechanics | "Pain while exercising was significantly reduced in the ACL patients. The authors concluded that lower body positive pressure exercise is effective at reducing ground reaction forces, while facilitating gait postoperatively." (First UCSD study) "Gait and EMG activity were largely unaffected except at 20% of body weight." (First UCSD study) "Gait kinematics to be only marginally effected at the lower body weights." (University of Colorado study) "Clinical experience clearly indicates the utility of the G-Trainer in the rehabilitation of a wide variety of orthopedic patients." (Clinical Performance Data Summary) "The clinic... concluded it to be a safe and effective tool in the clinical setting." (Device Design Validation Trial) |
| Substantial equivalence to predicate devices | "The G-Trainer has the same intended use as the predicate devices. The treadmills used in both the predicate and G-Trainer devices have the same performance and safety characteristics. The unweighting system used in the G-Trainer, although technologically different from the predicate devices, has been demonstrated through verification and validation testing, as well as clinical experience, to be as effective at reducing effective body weight as those systems used by the predicate devices." (Substantial Equivalence Conclusion/Summary) |
2. Sample Sizes Used for the Test Set and Data Provenance
The document describes several studies, which cumulatively serve as the "test set" for validating the device's performance, safety, and effectiveness. There isn't a single "test set" in the sense of a machine learning evaluation.
- Study 1 (Feasibility - VA): Eight healthy male subjects (29 to 52 years of age). Prospective. Data provenance not specified beyond "Veterans Administration Rehabilitation Research and Development Center in Palo Alto, California."
- Study 2 (Cardiopulmonary Response - VA): Nine subjects with stable cardiovascular or respiratory disease. Prospective. Data provenance as above.
- Study 3 (Ground Reaction Force - VA): Ten healthy individuals. Prospective. Data provenance as above.
- Study 4 (ACL/Meniscectomy - UCSD): Fifteen patients that had undergone ACL reconstruction or arthroscopic meniscectomy. Prospective. Data provenance not specified beyond "University of California, San Diego."
- Study 5 (Cardiovascular/Gait Changes - UCSD): Nine subjects (for cardiovascular response), six of whom were also studied for gait changes. Prospective. Data provenance as above.
- Study 6 (Runners - University of Colorado): Ten healthy recreational runners. Prospective. Data provenance "University of Colorado, Department of Integrative Biology."
- Study 7 (Device Design Validation Trial - Ergo-Rehab): 470 clients (375 orthopedic problems, 95 general cardiovascular conditioning). Prospective/Retrospective observation. Data provenance "physical therapy clinic, Ergo-Rehab, of Fremont, CA". This was an 18-month observational period.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications
This device is not an AI diagnostic tool and does not rely on "ground truth" derived from expert image interpretation in the typical sense. Instead, the studies involved medical professionals and researchers to conduct and interpret physiological measurements and clinical outcomes.
- First VA Study: Dr. Robert Whalen (inventor, likely a researcher/engineer) and collaborators from the Veterans Administration Rehabilitation Research and Development Center.
- Second and Third VA Studies: Researchers from the Veterans Administration Rehabilitation Research and Development Center.
- UCSD Studies: Dr. Alan Hargens (co-inventor, researcher at University of California, San Diego) and his laboratory.
- University of Colorado Study: Researchers from the Department of Integrative Biology.
- Device Design Validation Trial (Ergo-Rehab): The clinic provided monthly reports of patient use, pathologies rehabilitated, and comments. This implies clinical assessment by therapists/clinicians at the clinic, but specific "experts" for ground truth establishment are not detailed. The "System operators will be trained medical practitioners operating from clinics, hospitals and research facilities."
4. Adjudication Method for the Test Set
Adjudication methods like "2+1" or "3+1" are not applicable to the physiological and clinical outcome measurements described for the G-Trainer. These studies involved direct measurements and clinical observation, not subjective interpretations requiring adjudication among multiple readers.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
No MRMC study was performed because the G-Trainer is a physical device for rehabilitation, not an AI system assisting human readers in diagnostic tasks. Therefore, the concept of "effect size of how much human readers improve with AI vs. without AI assistance" is not relevant.
6. Standalone (Algorithm Only) Performance
The G-Trainer is not an algorithm, but a physical medical device. The "Non-Clinical Performance Data" section describes "verification testing" where the device's accuracy in adjusting body weight was directly measured without human intervention beyond operating the control panel. This could be considered a form of "standalone" performance for the core mechanical function.
7. Type of Ground Truth Used
The "ground truth" for the G-Trainer's validation included:
- Physiological Measurements: Measured body weight on a calibrated scale, ground reaction force (measured using force plates), heart rate, blood pressure.
- Clinical Outcomes/Observations: Reduction in pain, gait changes, EMG activity, and general clinical effectiveness and safety as observed by physical therapy clinics.
- Metabolic Demand: Measured during exercise.
These are objective or semi-objective measurements and clinical assessments, not expert consensus on qualitative data like images.
8. Sample Size for the Training Set
The concept of a "training set" is not applicable as the G-Trainer is a physical device and not an AI/machine learning algorithm that requires training data. The development prototypes and early iterations could be considered analogous to a design and refinement process, but not a data-driven "training" in the ML sense.
9. How the Ground Truth for the Training Set Was Established
As there is no "training set" in the AI sense, this question is not applicable. The device's design was based on scientific principles (air pressure differential technology) initially conceived at NASA and refined through the studies mentioned.
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The ACE/PP is intended to exercise the lower leg to help prevent vein thrombosis secondary to venous stasis and blood pooling in the leg. It also retains the exercise function for maintaining muscle tone and preventing stiffness in the ankle joints.
The ACE/PP is a compact portable exercise device with motor driven foot paddles. The product is controlled by the staff or the patient via an air switch. The paddles are driven in a natural and gentle dorsiflex motion.
This document, K952975, is a 510(k) summary for a medical device submitted in 1996. The information provided is very limited and predates many of the standardized reporting requirements for clinical studies now common in medical device submissions.
Therefore, the requested information regarding acceptance criteria, specific study details, sample sizes, expert qualifications, and ground truth establishment is not present in the provided text. The document focuses primarily on establishing substantial equivalence to predicate devices rather than providing detailed performance study data.
Here's an analysis based on the available information and an explanation of why most of your requested points cannot be answered:
1. A table of acceptance criteria and the reported device performance
- Not Available. The document does not specify any quantitative "acceptance criteria" for device performance in terms of clinical outcomes (e.g., reduction in DVT rates, specific physiological measurements). It focuses on safety (meeting UL 544) and functional equivalence.
- Reported Device Performance: The primary stated performance aspects are:
- "motor driven foot paddles."
- "paddles are driven in a natural and gentle dorsiflex motion."
- "offers the user a means to exercise the lower leg and to minimize venous stasis in bedridden and immobile patients."
2. Sample sized used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)
- Not Available. The document makes no mention of a "test set" or any clinical study details that would involve a sample size or data provenance. The 510(k) submission primarily relies on a comparison to predicate devices.
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)
- Not Applicable/Not Available. Since no specific test set or clinical study is described, there's no mention of experts establishing ground truth for such a set.
4. Adjudication method (e.g. 2+1, 3+1, none) for the test set
- Not Applicable/Not Available. As no test set or clinical study is described, no adjudication method is mentioned.
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 exercise and phlebopump, not an imaging or diagnostic device that would typically involve "human readers" or "AI assistance." Therefore, an MRMC study is not relevant to this device's function or evaluation as described.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
- Not Applicable. This device is a mechanical exerciser, not an algorithm. Therefore, "standalone" algorithm performance is not relevant.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc)
- Not Available/Not Applicable. No explicit "ground truth" is mentioned because the submission does not describe a clinical study measuring specific outcomes against a definitive standard. The "truth" in this context is likely implied by the predicate devices' established clinical utility for preventing venous stasis and maintaining muscle tone.
8. The sample size for the training set
- Not Applicable/Not Available. This device is a mechanical device, not a machine learning model, so there is no concept of a "training set" in the context of this submission.
9. How the ground truth for the training set was established
- Not Applicable/Not Available. As above, no training set for an algorithm is involved.
Summary of What Is Present:
- Device Name: Prevent Products Ankle Calf Exerciser & Phlebopump (ACE/PP)
- Classification: Class II
- Intended Use: To exercise the lower leg to help prevent vein thrombosis secondary to venous stasis and blood pooling in the leg, and to maintain muscle tone and prevent stiffness in ankle joints.
- Safety Standard: Meets or exceeds UL 544.
- Method of Performance Evaluation (implied): Substantial equivalence to predicate devices (Ankle Calf Exerciser from Prevent Products, Inc., Toronto Lower Limb Model Mobilimb L2, PlexiPump from NuTech) based on similar indications for use and basic overall design.
In conclusion, the provided K952975 document focuses on establishing substantial equivalence for a mechanical device in the mid-1990s. The information requested regarding detailed study design, sample sizes, expert involvement, and specific acceptance criteria for clinical outcomes is not part of this type of submission from that era.
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