(196 days)
To generate deep heating within body tissues for the treatment of conditions such as relief of pain and muscle spasms.
The ViaTherm BOOST Diathermy System is a single-patient reusable device designed to be self-administered in the home by a non-technical, adult operator. Diathermy is the controlled production of "deep heating" beneath the skin in the subcutaneous tissues, deep muscles and joints for therapeutic purposes. The ViaTherm BOOST Diathermy System is a portable diathermy heat therapy system that uses a shortwave radiofrequency signal to provide diathermic heating of tissue. The ViaTherm BOOST Diathermy System consists of five (5) components: Power generator, Heat applicator garment, Battery charging cable, Velcro extender strap, Cotton pad. Electronic circuitry in the power generator components generates a radiofrequency (RF) signal at a frequency of 13.56 Megahertz (MHz). The radiofrequency signal is delivered to the heat applicator garment that uses induction coil (magnetic field) technology to produce electromagnetic fields external to the applicator. This energy is converted into heat by electromagnetically resistant body tissues. The power generator consists of a battery pack, voltage regulators, a power control and analogue sensor module, and an RF generator. A shielded 1/4" cable with 50 Ohms impedance connects the power generator to the heat applicator garment. The electrode consists of two flat spirals incorporated into the applicator garment. The spirals are each tuned to 50 Ohms. The power from the generator is split and sent to the two spirals, one of which is driven 180 degrees out of phase from the other.
The ViaTherm BOOST Diathermy System is a shortwave diathermy device intended to generate deep heating within body tissues for the treatment of conditions such as relief of pain and muscle spasms.
Here's an analysis of the acceptance criteria and supporting study information:
1. Acceptance Criteria and Device Performance
The primary performance criterion for the ViaTherm BOOST Diathermy System, as implied by comparison to its predicate device (Selicor D100), is its ability to raise tissue temperature.
| Acceptance Criteria (Implied from Predicate) | Reported Device Performance (ViaTherm BOOST) |
|---|---|
| Achieves 4°C temperature rise at 20 minutes | Achieves 4°C temperature rise at 25 minutes |
| Operating Frequency: 13.56 MHz | Operating Frequency: 13.56 MHz |
| RF Power: 8 to 40 watts | RF Power: 5 watts |
| Duty Cycle: Continuous Wave | Duty Cycle: Continuous Wave |
| Impedance: 50 Ohms nominal | Impedance: 50 Ohms nominal |
| Load Standing Wave Ratio: 1.6:1 max | Load Standing Wave Ratio: 3.0:1 max |
| Designed to meet IEC 60601-1 | Designed to meet IEC 60601-1, IEC 60601-1-2, IEC 60601-1-6, IEC 60601-1-11 |
| Coil design: Two helical coils | Coil design: Two flat spiral coils |
Note on Acceptance Criteria: The document describes the ViaTherm BOOST Diathermy System as "as safe and effective as the predicate device" and that "Performance data demonstrate that the BOOST Diathermy System is as safe and effective as predicate device." While a specific, quantitative acceptance criterion (e.g., minimum 4°C rise within a certain time frame) is not explicitly stated as such for the new device, the comparison to the predicate's thermal performance (4°C rise at 20 minutes) strongly implies that demonstrating a similar or acceptable thermal performance was a key criterion for the new device (achieving 4°C rise at 25 minutes). Other criteria relate to specifications and safety standards compliance.
2. Sample Size and Data Provenance
- Sample Size for Test Set:
- Phantom Test: Not specified as a number of samples, but "temperature testing was performed in a muscle/bone phantom". This refers to a simulated tissue environment, not human subjects.
- Clinical Test: Nine healthy subjects.
- Data Provenance: Not explicitly stated, but the clinical test involved "healthy subjects" and was performed by the submitting company (ViaTherm Therapeutics, LLC) to support market clearance in the US, suggesting the study was likely conducted domestically (US) and prospectively for the purpose of this submission. The document explicitly mentions "clinical test in nine healthy subjects was performed and the temperatures of tissue at the surface, 1cm and 2cm were measured."
3. Number of Experts and Qualifications for Ground Truth (Test Set)
This device is not an AI/imaging device requiring expert interpretation of results for ground truth. It's a therapeutic device with performance measured by physical parameters (temperature rise). Therefore, this section is not applicable. The "ground truth" for its performance is objective temperature measurements.
4. Adjudication Method (Test Set)
Not applicable as the "test set" involves objective temperature measurements in a phantom and healthy volunteers, not subjective human assessments requiring adjudication.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
No. This device is a therapeutic diathermy system, not an imaging or diagnostic device that would typically undergo an MRMC study for comparative effectiveness of human readers with or without AI assistance.
6. Standalone Performance Study
Yes, a standalone performance study was conducted.
- Phantom Study: "Temperature testing was performed in a muscle/bone phantom to assess the temperature rise in simulated tissue."
- Clinical Study: "A clinical test in nine healthy subjects was performed and the temperatures of tissue at the surface, 1cm and 2cm were measured."
These tests directly measure the device's ability to generate heat in simulated and live tissue, without human intervention in the device's core function.
7. Type of Ground Truth Used
- Objective Measurements: For the phantom study and the clinical study, the ground truth was objective temperature measurements at specific depths (surface, 1cm, 2cm) within the simulated tissue and healthy human tissue.
8. Sample Size for Training Set
This device is not an AI/machine learning device that requires a "training set" in the conventional sense. Its function is based on physical principles of radiofrequency heating. Therefore, this section is not applicable.
9. How Ground Truth for Training Set Was Established
Not applicable, as there is no "training set" for this type of device.
§ 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.