(268 days)
The Curapuls 670 is indicated to be used for applying therapeutic deep heat in body tissues for the treatment of selected medical conditions such as:
- Relieving pain;
- Reducing muscle spasm;
- Increasing range of motion of contracted joints using heat and stretch techniques; and
- Increasing blood flow to tissues in the treatment area.
The Curapuls 670 is a two-channel microprocessor-controlled unit for pulsed shortwave therapy. Through inductive electrodes (Circuplodes), high-frequency electric currents are produced within the body. Pulsed energy at 27.12 MHz is absorbed by soft tissues. Three sizes of Circuplodes (140mm, 90mm and elliptical) are available to accommodate different size treatment areas.
Deep heating of tissue is achieved with ease by means of inductive electrodes. The user can connect two applicators. Activation of each applicator can be controlled from the console menu.
This device is a prescription equipment. Use by any persons other than physicians is prohibited.
This document is a 510(k) clearance letter for a medical device called Curapuls 670, a shortwave diathermy unit. It details the device's characteristics, its comparison to a predicate device (BTL-703), and the non-clinical testing performed to establish its substantial equivalence.
However, the provided text does not contain information related to an AI/ML-driven device or a study involving human-in-the-loop performance, such as a multi-reader multi-case (MRMC) study. It describes a physical therapy device used for applying therapeutic deep heat. Therefore, most of the requested information regarding "acceptance criteria and the study that proves the device meets the acceptance criteria" in the context of AI/ML evaluation (e.g., sample size for test/training sets, data provenance, expert ground truth, adjudication methods, MRMC studies, standalone performance) is not applicable to this document.
The "acceptance criteria" and "study" described in this document are focused on demonstrating the safety and effectiveness of the Curapuls 670 as a medical device for therapeutic deep heating, primarily through non-clinical testing and comparison to a predicate device.
Let's extract what is available regarding acceptance criteria and the "study" (non-clinical testing) from the provided text:
Acceptance Criteria and Study for Curapuls 670 (Non-AI Device)
1. A table of acceptance criteria and the reported device performance:
The document doesn't present a formal table of quantitative acceptance criteria for performance in the way one might expect for an AI model (e.g., specific sensitivity/specificity thresholds). Instead, the "acceptance criteria" for this device are primarily met by demonstrating compliance with recognized medical device safety and performance standards and showing substantial equivalence to a legally marketed predicate device.
The reported "device performance" is primarily qualitative and centered around its stated indications for use and its electrical/thermal properties.
| Acceptance Criteria (Implied by Standards & Equivalence) | Reported Device Performance / Compliance |
|---|---|
| Safety & Essential Performance (Electrical, Mechanical) | Complies with IEC 60601-1, ANSI AAMI ES60601-1. Full electrical safety testing performed. |
| Electromagnetic Compatibility (EMC) | Complies with IEC 60601-1-2. EMC testing done to evaluate emissions and immunity. |
| Software Life Cycle Processes | Complies with IEC 62304. |
| Risk Management | Complies with ISO 14971. |
| Biocompatibility | Complies with ISO 10993-1, ISO 10993-5 (in vitro cytotoxicity), ISO 10993-10 (irritation and skin sensitization). |
| Usability | Usability assessments done to verify user interface, safety features, and satisfactory performance. |
| Therapeutic Efficacy (Heat Generation) | Demonstrated ability to maintain tissue temperature in the range of approximately 40-45°C in vivo. |
| Substantial Equivalence to Predicate Device | Indications for Use are identical. Technological characteristics (working frequency, energy type, user interface, firmware control) are mostly identical. Minor differences (power source, mode of operation, applicator attachments, dimensions) are discussed and deemed not to raise new questions of safety or effectiveness. |
| Ability to achieve stated Indications for Use | "Used for applying therapeutic deep heat in body tissues in adults for the treatment of selected medical conditions such as: 1. Relieving pain; 2. Reducing muscle spasm; 3. Increasing range of motion of contracted joints using heat and stretch techniques; and 4. Increasing blood flow to tissues in the treatment area." The thermal effect on tissue testing supports this. |
2. Sample sized used for the test set and the data provenance:
- Sample Size: Not applicable in the context of a dataset for an AI model. The document refers to "final, finished devices" undergoing testing. The number of physical devices tested isn't specified, but it's a small manufacturing sample for validation, not a large patient data sample.
- Data Provenance: Not applicable for an AI dataset. The "data" here refers to test results from physical devices.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- Not applicable as this is not an AI/ML device requiring expert labeling of data. The ground truth for performance is based on established engineering and medical device standards (e.g., temperature measurements, electrical safety parameters, usability assessments).
4. Adjudication method (e.g. 2+1, 3+1, none) for the test set:
- Not applicable. This is not a study involving human reader interpretations that require adjudication.
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. An MRMC comparative effectiveness study was not done. This is not an AI-assisted diagnostic or interpretative device.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:
- Not applicable. This is not an algorithm. The device's performance is inherently "standalone" in the sense that it performs its physical function (producing heat) independently, but it is operated by a human user (a physician).
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc):
- The "ground truth" for this device's performance is based on:
- Engineering specifications and regulatory standards: Compliance with IEC, ISO, and ANSI/AAMI standards for electrical safety, EMC, biocompatibility, and software quality.
- In vivo thermal measurements: Direct measurement of tissue temperature increase (40-45°C) to validate the therapeutic heating capability.
- Usability assessments: Evaluation of the user interface and safety features by presumably qualified personnel to ensure satisfactory operation.
8. The sample size for the training set:
- Not applicable. This is not an AI/ML device trained on a dataset.
9. How the ground truth for the training set was established:
- Not applicable. There is no training set for an AI model.
In summary, the provided FDA 510(k) clearance letter pertains to a non-AI medical device (Shortwave Diathermy). Therefore, the detailed questions appropriate for an AI/ML device's validation study are largely irrelevant to this document. The "acceptance criteria" are met by demonstrating compliance with established safety and performance standards relevant to physical therapy equipment and showing substantial equivalence to a predicate device.
FDA 510(k) Clearance Letter - Curapuls 670
Page 1
U.S. Food & Drug Administration
10903 New Hampshire Avenue
Silver Spring, MD 20993
www.fda.gov
Doc ID # 04017.07.05
June 25, 2025
Enraf-Nonius, B.V.
℅ Scott Blood
Principal Regulatory Consultant
QARA Consulting LLC
151 Gleasondale Road
Stow, Massachusetts 01775
Re: K243112
Trade/Device Name: Curapuls 670
Regulation Number: 21 CFR 890.5290
Regulation Name: Shortwave Diathermy
Regulatory Class: Class II
Product Code: IMJ
Dated: September 30, 2024
Received: September 30, 2024
Dear Scott Blood:
We have reviewed your section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (the Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. Although this letter refers to your product as a device, please be aware that some cleared products may instead be combination products. The 510(k) Premarket Notification Database available at https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm identifies combination product submissions. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.
If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. In addition, FDA may publish further announcements concerning your device in the Federal Register.
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K243112 - Scott Blood
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Additional information about changes that may require a new premarket notification are provided in the FDA guidance documents entitled "Deciding When to Submit a 510(k) for a Change to an Existing Device" (https://www.fda.gov/media/99812/download) and "Deciding When to Submit a 510(k) for a Software Change to an Existing Device" (https://www.fda.gov/media/99785/download).
Your device is also subject to, among other requirements, the Quality System (QS) regulation (21 CFR Part 820), which includes, but is not limited to, 21 CFR 820.30, Design controls; 21 CFR 820.90, Nonconforming product; and 21 CFR 820.100, Corrective and preventive action. Please note that regardless of whether a change requires premarket review, the QS regulation requires device manufacturers to review and approve changes to device design and production (21 CFR 820.30 and 21 CFR 820.70) and document changes and approvals in the device master record (21 CFR 820.181).
Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Part 801); medical device reporting (reporting of medical device-related adverse events) (21 CFR Part 803) for devices or postmarketing safety reporting (21 CFR Part 4, Subpart B) for combination products (see https://www.fda.gov/combination-products/guidance-regulatory-information/postmarketing-safety-reporting-combination-products); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820) for devices or current good manufacturing practices (21 CFR Part 4, Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR Parts 1000-1050.
All medical devices, including Class I and unclassified devices and combination product device constituent parts are required to be in compliance with the final Unique Device Identification System rule ("UDI Rule"). The UDI Rule requires, among other things, that a device bear a unique device identifier (UDI) on its label and package (21 CFR 801.20(a)) unless an exception or alternative applies (21 CFR 801.20(b)) and that the dates on the device label be formatted in accordance with 21 CFR 801.18. The UDI Rule (21 CFR 830.300(a) and 830.320(b)) also requires that certain information be submitted to the Global Unique Device Identification Database (GUDID) (21 CFR Part 830 Subpart E). For additional information on these requirements, please see the UDI System webpage at https://www.fda.gov/medical-devices/device-advice-comprehensive-regulatory-assistance/unique-device-identification-system-udi-system.
Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to https://www.fda.gov/medical-devices/medical-device-safety/medical-device-reporting-mdr-how-report-medical-device-problems.
For comprehensive regulatory information about medical devices and radiation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/medical-devices/device-advice-comprehensive-regulatory-assistance) and CDRH Learn (https://www.fda.gov/training-and-continuing-education/cdrh-learn). Additionally, you may contact the Division of Industry and Consumer Education (DICE) to ask a question about a specific regulatory topic. See the DICE website (https://www.fda.gov/medical-devices/device-advice-comprehensive-regulatory-
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K243112 - Scott Blood
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assistance/contact-us-division-industry-and-consumer-education-dice) for more information or contact DICE by email (DICE@fda.hhs.gov) or phone (1-800-638-2041 or 301-796-7100).
Sincerely,
Lauren E. Woodard -S
for Amber Ballard, PhD
Assistant Director
DHT5B: Division of Neuromodulation and Physical Medicine Devices
OHT5: Office of Neurological and Physical Medicine Devices
Office of Product Evaluation and Quality
Center for Devices and Radiological Health
Enclosure
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DEPARTMENT OF HEALTH AND HUMAN SERVICES
Food and Drug Administration
Indications for Use
Form Approved: OMB No. 0910-0120
Expiration Date: 07/31/2026
See PRA Statement below.
Submission Number (if known)
K243112
Device Name
Curapuls 670
Indications for Use (Describe)
The Curapuls 670 is indicated to be used for applying therapeutic deep heat in body tissues for the treatment of selected medical conditions such as:
- Relieving pain;
- Reducing muscle spasm;
- Increasing range of motion of contracted joints using heat and stretch techniques; and
- Increasing blood flow to tissues in the treatment area.
Type of Use (Select one or both, as applicable)
☒ Prescription Use (Part 21 CFR 801 Subpart D) ☐ Over-The-Counter Use (21 CFR 801 Subpart C)
CONTINUE ON A SEPARATE PAGE IF NEEDED.
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DO NOT SEND YOUR COMPLETED FORM TO THE PRA STAFF EMAIL ADDRESS BELOW.
The burden time for this collection of information is estimated to average 79 hours per response, including the time to review instructions, search existing data sources, gather and maintain the data needed and complete and review the collection of information. Send comments regarding this burden estimate or any other aspect of this information collection, including suggestions for reducing this burden, to:
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Page 5
510(k) Summary
Curapuls 670
Page 1 of 5
1. Basic Information-Submitter:
510(k) Owner: Enraf-Nonius B.V
127, Vareseweg
Rotterdam, Zuid-Holland, NL-3047AT
THE NETHERLANDS
Official Correspondent: Scott Blood
Principal Consultant
Phone: 978.729.5978
Fax: +49 731 9761 118
E-Mail: scottqara@gmail.com
Date Summary Prepared: May 27, 2025
2. Device Name:
Trade Name: Curapuls 670
Classification Name: Diathermy, Shortwave, For the Use in Applying Therapeutic Deep Heat
Regulation Number: 890.5290
Product Code: IMJ
Classification: Class II
3. Predicate Device:
BTL-703
Company Name: BTL Industries, Inc.
K182363
4. Device Description:
The Curapuls 670 is a two-channel microprocessor-controlled unit for pulsed shortwave therapy. Through inductive electrodes (Circuplodes), high-frequency electric currents are produced within the body. Pulsed energy at 27.12 MHz is absorbed by soft tissues. Three sizes of Circuplodes (140mm, 90mm and elliptical) are available to accommodate different size treatment areas.
Deep heating of tissue is achieved with ease by means of inductive electrodes. The user can connect two applicators. Activation of each applicator can be controlled from the console menu.
This device is a prescription equipment. Use by any persons other than physicians is prohibited.
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5. Indications for Use Statement:
| Indications for Use | SUBJECT DEVICEEnraf-Nonius B.V.Curapuls 670This Submission | PREDICATE DEVICEBTL Industries, Inc.BTL-703K182363 |
|---|---|---|
| Indications for Use | Used for applying therapeutic deep heat in body tissues in adults for the treatment of selected medical conditions such as: 1. Relieving pain; 2. Reducing muscle spasm; 3. Increasing range of motion of contracted joints using heat and stretch techniques; and 4. Increasing blood flow to tissues in the treatment area. | Used for applying therapeutic deep heat in body tissues for the treatment of selected medical conditions such as: 1. Relieving pain; 2. Reducing muscle spasm; 3. Increasing range of motion of contracted joints using heat and stretch techniques; and 4. Increasing blood flow to tissues in the treatment area. |
The Indications for Use statement for Curapuls 670 is similar to the predicate device.
6. Technological Characteristics:
Both the subject device and predicate device use the same frequency (27.12 MHz) to meet their Indications for Use. The devices are mostly technologically equivalent. The minor differences shown below do not raise new questions of safety or effectiveness.
| Technological Characteristics | SUBJECT DEVICEEnraf-Nonius B.V.Curapuls 670This Submission | PREDICATE DEVICEBTL Industries, Inc.BTL-703K182363 | Substantial Equivalence Comments |
|---|---|---|---|
| Working Frequency | 27.12 MHz | 27.12 MHz | Identical |
| Power source | 100 – 240 VAC +/- 10% | Internal, 120 VAC | Different |
| Peak Output Power | 200 W | 2 x 100 W (Continuous) | Similar |
| Pulse Width | 65 – 400 µs | Not publicly available | -------- |
| Pulse Frequency | 26 – 800 Hz | Not publicly available | ------- |
| Mean Power | 0 – 64 W | Not publicly available | ------- |
| Electrical Protection | Class II, BF | Class II, BF | Identical |
| User Interface | Touchscreen | Touchscreen | Identical |
| Firmware Controlled | Yes | Yes | Identical |
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Page 3 of 5
| Technological Characteristics | SUBJECT DEVICEEnraf-Nonius B.V.Curapuls 670This Submission | PREDICATE DEVICEBTL Industries, Inc.BTL-703K182363 | Substantial Equivalence Comments |
|---|---|---|---|
| Energy Type | High-frequency electromagnetic current | High-frequency electromagnetic current | Identical |
| Mode of Operation | Pulsed | Continuous | Different |
| Applicator type | Capacitive | Capacitive | Identical |
| Applicator size | 90 mm diameter140 mm diameterOval | 100mm diameter | Similar |
| Indicator DisplayOn/Off Status?Low Battery?Voltage/Current level? | YesYesYes | YesYesYes | Identical |
| Way of Applicator Attachment | Mechanical | Negative Pressure | Different |
| Applicator sleeves | No | Yes | Different |
| Thermal Stabilization System | No | Yes | Different |
| Arm Control | Mechanical | Electrical / Mechanical | Similar |
| Hands-Free Application | Yes | Yes | Identical |
| Stop Remote Control | Yes | Yes | Identical |
| Applicator Contact Monitor | No | Yes | Different |
| Timer Range (minutes) | 0 – 30 min | 0 – 30 min | Identical |
| Compliance to Standards | IEC 60601-1IEC 60601-1-2IEC 62304ISO 14971ISO 10993-1ISO 10993-5ISO 10993-10 | IEC 60601-1IEC 60601-1-2IEC 62304ISO 14971ISO 10993-1ISO 10993-5ISO 10993-10 | Identical |
| Weight | 60 lbs | Not publicaly available | Unknown |
| Dimensions (W x H x D) | 22.0" x 43.3" x 18.9" | 24.7" x 38.8" x 26.5" | Different |
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| Technological Characteristics | SUBJECT DEVICEEnraf-Nonius B.V.Curapuls 670This Submission | PREDICATE DEVICEBTL Industries, Inc.BTL-703K182363 | Substantial Equivalence Comments |
|---|---|---|---|
| Housing Materials and Construction | Aluminum, polycarbonate-ABS, polycarbonate, ABS, glass, polyethlyene, POM | Not publicly available | ------- |
Discussion of Differences
Indications for use are identical for both subject and predicate devices.
| Technological Characteristics | Characteristic differences between Curapuls 670 and predicate device | Discussion on why this difference does not affect the overall safety and effectiveness of the subject device when compared to the predicate device |
|---|---|---|
| Mode of Operation | Pulsed versus Continuous | Both pulses and continuous modes of shortwave diathermy are used in already-cleared medical devices. While continuous mode does allow for faster temperature rise in tissue, both modes have been tested for thermal effect in tissue as part of device clearance. |
| Way of Application Attachment | Mechanical versus Negative Pressure | The predicate device uses negative pressure to hold the applicator in place on the patient's skin. The silicone applicator sleeves, thermal stabilization system, and applicator contact monitor are all part of that negative pressure system. The subject device uses a mechanical arm system to hold the applicator in position. The negative pressure applicator accessories are not needed when mechanical means of applicator attachment are employed. |
| Applicator sleeves | None versus Yes | |
| Thermal Stabilization System | None versus Yes | |
| Applicator Contact Monitor | None versus Yes | |
| Power Source | 100 – 240 VAC +/- 10% versus 120 VAC | Subject device has been tested for electrical safety per IEC 60601-1. The power source does not create any new questions of safety and effectiveness. |
| Dimensions | 22.0" x 43.3" x 18.9" versus 24.7" x 38.8" x 26.5" | Different form factor has no influence on the safety or effectiveness of the device. |
7. Summary of Non-clinical Testing:
The technological characteristics of the Curapuls 670 device has been verified based on assessments of electrical safety, performance, biocompatibility, software and usability.
The device has been found to comply with applicable medical device safety standards:
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Page 5 of 5
-
IEC 60601-1 Medical electrical equipment – Part 1: General requirements for basic safety and essential performance
-
IEC 60601-1-2 Medical electrical equipment – Part 1-2: General requirements for basic safety and essential performance - Collateral standard: Electromagnetic Disturbance – Requirements and tests
-
IEC 62304 Medical device software – Software life cycle processes
-
ISO 14971 Medical devices – Application of risk management to medical devices
-
ISO 10993-1 Biological evaluation of medical devices – Part 1: Evaluation and testing within a risk management process
-
ISO 10993-5 Biological evaluation of medical devices – Part 5: Tests for in vitro cytotoxicity
-
ISO 10993-10 Biological evaluation of medical devices – Part 10: Tests for irritation and skin sensitization
The following testing has been conducted with satisfactory results:
-
Usability: Usability assessments were done to verify user interface, safety features and satisfactory performance.
-
Electromagnetic compatibility: EMC testing was done to evaluate emissions and immunity to electromagnetic fields in accordance with IEC 60601-1-2.
-
Electrical and mechanical safety: Full electrical safety testing was done in compliance with ANSI AAMI ES60601-1.
-
Thermal effect on tissue: Demonstrated the device is able to maintain temperature in the range of approximately 40-45°C in vivo.
Testing has been performed on final, finished devices and these systems have met the required specifications for the completed tests.
8. Conclusion:
There are no differences with respect to the indications for use and many of the technological characteristics between the Curapuls 670 and the predicate device. The minor differences mentioned above do not raise new questions of safety or effectiveness.
§ 890.5290 Shortwave diathermy.
(a)
Shortwave diathermy for use in applying therapeutic deep heat for selected medical conditions —(1)Identification. A shortwave diathermy for use in applying therapeutic deep heat for selected medical conditions is a device that applies to specific areas of the body electromagnetic energy in the radiofrequency (RF) bands of 13.56 megahertz (MHz) or 27.12 MHz and that is intended to generate deep heat within body tissues for the treatment of selected medical conditions such as relief of pain, muscle spasms, and joint contractures, but not for the treatment of malignancies.(2)
Classification. Class II (performance standards).(b)
Nonthermal shortwave therapy —(1)Identification. A nonthermal shortwave therapy is a prescription device that applies to the body pulsed electromagnetic energy in the RF bands of 13.56 MHz or 27.12 MHz and that is intended for adjunctive use in the palliative treatment of postoperative pain and edema of soft tissue by means other than the generation of deep heat within body tissues as described in paragraph (a) of this section.(2)
Classification: Class II (special controls). The device is classified as class II. The special controls for this device are:(i) Components of the device that come into human contact must be demonstrated to be biocompatible.
(ii) Appropriate analysis/testing must demonstrate that the device is electrically safe and electromagnetically compatible in its intended use environment.
(iii) Non-clinical performance testing must demonstrate that the device performs as intended under anticipated conditions of use. Non-clinical performance testing must characterize the output waveform of the device and demonstrate that the device meets appropriate output performance specifications. The output characteristics and the methods used to determine these characteristics, including the following, must be determined:
(A) Peak output power;
(B) Pulse width;
(C) Pulse frequency;
(D) Duty cycle;
(E) Characteristics of other types of modulation that may be used;
(F) Average measured output powered into the RF antenna/applicator;
(G) Specific absorption rates in saline gel test load or other appropriate model;
(H) Characterization of the electrical and magnetic fields in saline gel test load or other appropriate model for each RF antenna and prescribed RF antenna orientation/position; and
(I) Characterization of the deposited energy density in saline gel test load or other appropriate model.
(iv) A detailed summary of the clinical testing pertinent to use of the device to demonstrate the effectiveness of the device in its intended use.
(v) Labeling must include the following:
(A) Output characteristics of the device;
(B) Recommended treatment regimes, including duration of use; and
(C) A detailed summary of the clinical testing pertinent to the use of the device and a summary of the adverse events and complications.
(vi) Nonthermal shortwave therapy devices marketed prior to the effective date of this reclassification must submit an amendment to their previously cleared premarket notification (510(k)) demonstrating compliance with these special controls.