(98 days)
The UltraShape Power System delivers focused ultrasound energy that can disrupt subcutaneous adipose tissue (SAT) for lipolysis (breakdown of fat) to provide a non-invasive approach to achieve a desired aesthetic effect. It is intended for non-invasive reduction in abdominal circumference and fat reduction in the flanks and thighs.
The UltraShape Power System is comprised of multiple components, including the control unit and an ultrasonic transducer. The UltraShape Power System selectively targets subcutaneous adipose tissue via focused ultrasound for the purpose of non-invasive aesthetic body contouring. The transducer is an electro-mechanical device that converts an electrical signal into mechanical (acoustical) energy. The operating parameters of the UltraShape Power System achieve selective disruption of adipose tissue without damaging neighboring tissues such as blood vessels, nerves, or muscle.
Here's a breakdown of the acceptance criteria and study information for the UltraShape Power System, based on the provided document:
Acceptance Criteria and Device Performance
| Criteria | Reported Device Performance |
|---|---|
| Primary Endpoint for Flanks Study: At least 80% of treated versus control flanks and pre-versus post-treatment photographs were correctly identified by 2 blinded reviewers. | Met Endpoint: Blinded reviewers (by agreement between the blinded reviewers) correctly identified both the pre-/post-treatment photographs as well as the treated/un-treated flanks in 80% (36 of 45) subjects. |
| Secondary Endpoints for Flanks Study: | |
| - Fat thickness reduction on the treated flank compared to the control flank, measured by ultrasound.** | Statistically Significant: Fat thickness reduction results following UltraShape treatment were statistically significantly greater compared to controls as measured by ultrasound. |
| - Fat thickness reduction on the treated flank compared to the control flank, measured by caliper. | Greater Reduction: Fat thickness reduction results following UltraShape treatment were greater compared to controls as measured by caliper (reaching statistical significance in absolute fat thickness reduction at 16 week follow up). |
| - Investigator satisfaction assessment. | Satisfied: Investigators were satisfied with results following UltraShape treatment for 70% of the subjects at 4 week follow up, 53% of the subjects at 8 week follow up, and 43% of the subjects at 16 week follow up. |
| - Subject satisfaction self-assessment. | Satisfied: At 4, 8, and 16 weeks following end of treatments, 43%, 47%, and 41% of the subjects were satisfied or very satisfied. |
| - Subjects' comfort level assessed immediately after each treatment. | No to Minimal Pain: Subjects reported no to minimal pain for each of the three treatments. |
| Safety Results for Flanks Study: No adverse events reported. | Met: No adverse events were reported after 141 treatment sessions were conducted. The only immediate responses recorded were mild and resolved completely within days without any intervention. |
| Primary Endpoint for Thighs Study: At least 80% of treated versus untreated thighs and pre-versus post-treatment photographs were correctly identified by 2 blinded reviewers. | Met Endpoint: Blinded reviewers (by agreement between the blinded reviewers) correctly identified both the pre-/post-treatment photographs as well as the treated/un-treated thighs in 81% (30 of 37) subjects. (Even with worst case imputation for missing data, 64% were successes). |
| Secondary Endpoints for Thighs Study: | |
| - Circumference reduction on treated thigh compared to control thigh. | Statistically Significant: UltraShape treated thighs showed statistically significantly greater circumference reduction compared to the control thighs at each follow up visit. |
| - Fat thickness reduction on the treated thigh compared to the control thigh, measured by ultrasound. | Statistically Significant: Fat thickness reduction results following UltraShape treatment were statistically significantly greater compared to controls as measured by ultrasound. |
| - Fat thickness reduction on the treated thigh compared to the control thigh, measured by caliper. | Greater Reduction: Fat thickness reduction results following UltraShape treatment were greater compared to controls as measured by caliper, although the difference was not statistically significant at all visits. |
| - Investigator satisfaction assessment. | Satisfied: Investigators were satisfied with results following UltraShape treatment for 77% of the subjects at 4 week follow up, 81% of the subjects at 8 week follow up, and 68% of the subjects at 16 week follow up. |
| - Subject satisfaction self-assessment. | Satisfied: At 4, 8 and 16 weeks following end of treatments, 62%, 61% and 68% of the subjects were satisfied or very satisfied. |
| - Subjects' comfort level assessed immediately after each treatment. | No to Minimal Pain: Subjects reported no to minimal pain on average for each of the three treatments. |
| Safety Results for Thighs Study: No adverse events reported. | Met: No adverse events were reported after 128 treatment sessions were conducted. The only immediate responses recorded were mild and resolved completely within days without any intervention. |
Study Information
The document describes two separate clinical studies, one for the flanks and one for the thighs.
1. Sample size used for the test set and the data provenance
- Flanks Study:
- Sample Size: 48 subjects enrolled and treated (46 completed the study).
- Data Provenance: Prospective, multi-center clinical study conducted at 3 U.S. sites.
- Test Set Description: Each subject received 3 biweekly treatments on one randomized flank, while the other flank remained un-treated throughout the study (serving as an internal control). Follow-up was at 4, 8, and 16 weeks after the last treatment. Comparisons were made between treated vs. control flanks and pre- vs. post-treatment.
- Thighs Study:
- Sample Size: 47 subjects enrolled.
- Data Provenance: Prospective, multi-center clinical study conducted at 3 U.S. sites.
- Test Set Description: Each subject received 3 biweekly treatments on one randomized thigh, while the other thigh remained un-treated (serving as an internal control). Follow-up was at 4, 8, and 16 weeks after the last treatment. Comparisons were made between treated vs. control thighs and pre- vs. post-treatment.
2. Number of experts used to establish the ground truth for the test set and the qualifications of those experts
- Number of Experts: 2 blinded reviewers were used for both the flanks and thighs studies.
- Qualifications: The specific qualifications of the reviewers (e.g., dermatologists, plastic surgeons, years of experience) are not explicitly stated in the provided text. They are simply referred to as "blinded reviewers."
3. Adjudication method for the test set
- Adjudication Method: For both flanks and thighs studies, the primary endpoint was considered met if the reviewers "identified correctly (by agreement between the blinded reviewers)" the pre-/post-treatment and treated/un-treated images. This indicates that agreement between the two reviewers was required for a successful identification. This can be considered a form of "consensus" 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, an MRMC comparative effectiveness study involving AI assistance was NOT done. The studies described evaluate the device's efficacy in achieving fat reduction, with visual assessment by human reviewers as one endpoint. The device itself is for fat reduction, not for diagnostic assistance that would typically involve AI.
5. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
- Not applicable. The UltraShape Power System is a medical device that delivers focused ultrasound energy for lipolysis. It is not an AI algorithm for diagnostic purposes. The evaluation is of the direct physical effect of the device on the body.
6. The type of ground truth used (expert consensus, pathology, outcomes data, etc.)
-
For Efficacy (Fat Reduction):
- Visual Assessment: Expert consensus (agreement between 2 blinded reviewers) on identifying treated vs. control and pre- vs. post-treatment photographs.
- Objective Measurements: Pathology (not directly, but indirectly by measuring fat thickness reduction via ultrasound and caliper, which are objective clinical measurements representing the outcome of lipolysis).
- Outcomes Data: Investigator satisfaction, subject satisfaction, and comfort level self-assessments were also gathered as secondary outcomes.
-
For Safety: Clinical observation of adverse events and immediate responses.
7. The sample size for the training set
- Not applicable. The provided text describes clinical studies evaluating a physical medical device. It does not mention a "training set" in the context of an AI algorithm. The device's technological characteristics and settings (frequency, burst duration, node duration, user interface, power intensity levels, focal distribution) were "previously cleared" or "previously conducted" in relation to predicate devices, implying prior developmental testing and optimization, but not necessarily a "training set" in the machine learning sense.
8. How the ground truth for the training set was established
- Not applicable. As the concept of a "training set" for an AI algorithm is not relevant here, the establishment of ground truth for such a set is also not discussed. The clinical studies aim to demonstrate the device's effectiveness and safety, not to train an algorithm.
§ 878.4590 Focused ultrasound stimulator system for aesthetic use.
(a)
Identification. A Focused Ultrasound Stimulator System for Aesthetic Use is a device using focused ultrasound to produce localized, mechanical motion within tissues and cells for the purpose of producing either localized heating for tissue coagulation or for mechanical cellular membrane disruption intended for noninvasive aesthetic use.(b)
Classification. Class II (special controls). The special control for this device is FDA's “Class II Special Controls Guidance Document: Focused Ultrasound Stimulator System for Aesthetic Use.” See § 878.1(e) for the availability of this guidance document.