Ultrasonic Diathermy (Physiotherapy) Devices - Technical and Safety Requirements for 510k Submissions
This guidance applies to ultrasonic diathermy (physiotherapy) devices regulated under 21 CFR 890.5300(a) that: - Apply therapeutic deep heat for medical conditions like pain relief, muscle spasms, and joint contractures - Operate at frequencies above 20 kHz - Use a single plane circular transducer per treatment head - Produce non-convergent beams perpendicular to the treatment head face
What You Need to Know? 👇
What documentation level is required for ultrasonic diathermy device software in 510(k) submissions?
Ultrasonic diathermy devices should generally address recommendations for an Enhanced Documentation Level based on FDA’s 2023 guidance “Content of Premarket Submissions for Device Software Functions,” replacing the previous Major Level of Concern classification.
Which IEC standards are most critical for ultrasonic diathermy device 510(k) submissions?
Key standards include IEC 60601-2-5 for ultrasonic physiotherapy equipment, IEC 61689 for ultrasonic fields, ANSI/AAMI ES60601-1 for electrical safety, and IEC 60601-1-2 for electromagnetic compatibility testing and documentation.
What are the maximum allowable intensity and beam non-uniformity ratio limits for these devices?
The effective intensity must not exceed 3 W/cm² and the beam non-uniformity ratio must not exceed 8, according to IEC 60601-2-5 standard requirements for safe therapeutic ultrasound delivery.
What biocompatibility testing endpoints are required for ultrasonic diathermy devices?
As surface devices with intact skin contact and limited duration exposure, required endpoints include cytotoxicity, skin sensitization, and irritation testing per ISO 10993-1 guidance for patient-contacting materials.
Do ultrasonic coupling gels require separate FDA clearance for these devices?
Yes, acoustic coupling gels are considered medical devices requiring their own 510(k) clearance. If using a new gel, you must identify an appropriate predicate with similar technological characteristics including sound velocity and acoustic impedance.
What are the key contraindications that must be included in device labeling?
Critical contraindications include use near implanted devices, over malignancies, on pregnant uterus, over healing fractures, in patients with thrombophlebitis, and over areas with vascular disease or recent bleeding.
What You Need to Do 👇
Recommended Actions
- Prepare comprehensive device description including all technical specifications
- Conduct required testing:
- Electrical safety and EMC
- Software validation
- Biocompatibility
- Performance testing for output parameters
- Develop complete labeling package including:
- Device and component identification
- Operating instructions
- Safety information
- Cleaning/reprocessing instructions
- Prepare 510(k) submission including:
- Detailed predicate comparison
- Test reports and validation data
- Risk analysis
- Complete labeling
- Ensure compliance with:
- Maximum treatment time limit
- Output intensity limits
- Safety requirements for patient contact
- Software documentation requirements
- Validate reprocessing procedures if device is reusable
- Implement cybersecurity measures if applicable
Key Considerations
Non-clinical testing
- Electrical safety and EMC testing according to ANSI/AAMI ES60601-1 and IEC 60601-1-2
- Performance testing to demonstrate output power and effective intensity specifications
- Validation of timer accuracy (±10% of setting)
- Validation of unwanted ultrasound radiation (<100 mW/cm2)
- Temperature rise characterization
Software
- Documentation level should be “Enhanced” (formerly “Major” level of concern)
- Full software description and validation documentation required
- Cybersecurity considerations if applicable
Cybersecurity
- Required if device includes wireless capabilities or networked features
- Address data integrity, coexistence, security aspects
Labelling
- Detailed device description including specifications
- Contraindications, warnings and precautions
- Operating instructions
- Cleaning/reprocessing instructions
- Device and treatment head identification/specifications
- Control labeling
Biocompatibility
- Testing for cytotoxicity, sensitization and irritation required
- Evaluation of transmission media (coupling gel)
Safety
- Maximum treatment time not exceeding 30 minutes
- Maximum effective intensity not exceeding 3 W/cm2
- Beam non-uniformity ratio not exceeding 8
- Moving treatment head requirement to avoid burns
Other considerations
- Wireless technology considerations if applicable
- Reprocessing validation if reusable device
Relevant Guidances đź”—
- Content of Premarket Submissions for Device Software Functions
- Cybersecurity in Medical Devices: Design, Implementation, and Premarket Submissions
- Use of ISO 10993-1 for Biological Evaluation and Testing of Medical Devices
- Reprocessing Instructions for Reusable Medical Devices and Non-Sterile Single-Use Devices - Development and Validation
- Electromagnetic Compatibility for Medical Devices and Accessories: Testing, Documentation, and Labeling Requirements
Related references and norms đź“‚
- IEC 61689: Ultrasonics - Physiotherapy systems - Field specifications and methods of measurement in the frequency range 0,5 MHz to 5 MHz
- IEC 60601-2-5: Medical electrical equipment - Part 2-5: Particular requirements for the basic safety and essential performance of ultrasonic physiotherapy equipment
- ANSI/AAMI ES60601-1: Medical electrical equipment - Part 1: General requirements for basic safety and essential performance
- ISO 10993-1: Biological evaluation of medical devices - Part 1: Evaluation and testing within a risk management process