(387 days)
As a TENS device, the Focus is indicated for the following conditions:
- symptomatic relief and management of chronic, intractable pain
- . adjunctive treatment for post-surgical and post-trauma acute pain
As a NMS/NMES device, the Focus is indicated for the following conditions:
- relaxation of muscle spasm .
- . prevention or retardation of disuse atrophy
- . increasing local blood circulation
- . muscle re-education
- prevention of venous thrombosis of the calf muscles inmediately after surgery
- maintaining or increasing range of motion
As a FES device, the Focus is indicated for the following vondition:
- stimulation of the muscles in the leg and ankle of part ally paralyzed patients to provide flexion of the foot and thus improve the patient's gait
The Focus Unit is a dual channel NMES/TENS device with four conventional modes of operation, eight pre-programmed regimens and a choice of two levels of output (0-40mA or 0-60mA). It is powered by a standard 9V alkaline or NiCad rechargeable battery. All operation modes produce the Empi Bi-Sourced® waveform.
The Focus Unit requires the use of a set of leadwires and one or two pair of electrodes. All NMES/TENS electrodes currently distributed by Empi are appropriate for use with the Focus. The use of other brands of electrodes is not recommended as the quality of those products is unknown and it has been observed that the quality of the clectrode may impact the ability of the Focus to operate efficiently, i.e., if the electrode does not adhere to the skin current will not be delivered.
The Empi Focus Model 795 is a Transcutaneous Electrical Nerve Stimulator (TENS), Powered Muscle Stimulator (NMES), and External Functional Neuromuscular Stimulator (FES) device.
Here's an analysis of the acceptance criteria and the study information provided:
1. Table of Acceptance Criteria and Reported Device Performance
The acceptance criteria for the Empi Focus Model 795 are based on its equivalence to existing predicate devices, specifically the Empi Focus Model 727 and the Empi Respond Select. The study establishes that the device meets these criteria by demonstrating technical and performance similarities.
| Characteristic | Acceptance Criteria (Predicate Devices - Focus 727 / Respond Select) | Reported Device Performance (Focus 795) | Meets Criteria? |
|---|---|---|---|
| No. Of Output Channels | 2 (Focus 727/Respond Select) | 2 | Yes |
| Standards | AAMI/ANSI NS4-1985, IEC 601-2-10, IEC 601-1-2 | AAMI/ANSI NS4-1985, IEC 601-2-10, IEC 601-1-2 | Yes |
| Current Range | 0-60mA (normal), 0-100mA (high) (Focus 727); 0-100 mA (alkaline), 0-90 mA (NiCd) (Respond Select) | 0-60mA (normal), 0-100mA (high) | Yes |
| Maximum Output Voltage (1kΩ load) | ± 100 V (Focus 727/Respond Select) | ± 100 V | Yes |
| Channel Interaction | ≤ 5% (Focus 727/Respond Select) | ≤ 5% | Yes |
| Pulse Width | 300µs at 50% of peak amplitude (Focus 727/Respond Select) | 300µs at 50% of peak amplitude | Yes |
| Waveforms | Symmetrical biphasic or balanced asymmetrical biphasic (Focus 727/Respond Select) | Symmetrical biphasic or balanced asymmetrical biphasic | Yes |
| Zero Net DC | Yes, controlled by transformer (Focus 727/Respond Select) | Yes, controlled by transformer | Yes |
| Maximum Phase Charge (1kΩ load) | 30µC (Focus 727/Respond Select) | 30µC | Yes |
| Pulse Rates | 25, 30, 35, 45, 50, 80 Hz (Focus 727); 1-80 Hz (Respond Select) | 25, 30, 35, 45, 50, 80 Hz | Yes |
| ON Times | 2.5, 5, 10, 15, 20, 25, 30, 50 sec (Focus 727); 2-60 sec, adjustable (Respond Select) | 2.5, 5, 10, 15, 20, 25, 30, 50 sec | Yes |
| OFF Times | 0, 5, 10, 15, 20, 25, 30, 50 sec (Focus 727); 2-120 sec, adjustable (Respond Select) | 0, 5, 10, 15, 20, 25, 30, 50 sec | Yes |
| Ramp Time | 2 sec up, fixed; 2 sec down, fixed (Focus 727); .2 - 10 sec up, adjustable; .1 - 5 sec down, adjustable (Respond Select) | 2 sec up, fixed; 2 sec down, fixed | Yes |
| Cycling Modes | Synchronous(S) or alternating(A) (Focus 727); synchronous or asynchronous (Respond Select) | Synchronous(S) or alternating(A) | Yes |
| Timing Control Modes | Continuous, normal operation, 15 or 30min (Focus 727); continuous, 15, 30, 60min (Respond Select) | Continuous, normal operation, 15 or 30min | Yes |
| Preprogrammed Regimens | 8 (Focus 727); 4 (Respond Select) | 8 | Yes |
| High Output Shutdown (Output Interlock) | NO (Focus 727); YES (Respond Select) | YES (This is an added safety feature and improves upon the Focus 727) | Yes |
| Waveform Change Interlock | YES (Focus 727/Respond Select) | YES | Yes |
| Compliance Timer | NO (Focus 727); YES (Respond Select) | NO | Yes (matches Focus 727) |
| Accessories | Hand Held Remote or Heel Switch (Focus 727/Respond Select) | Hand Held Remote or Heel Switch | Yes |
| Output Type | Constant current, 100Ω - 1kΩ (Focus 727/Respond Select) | Constant current, 100Ω - 1kΩ | Yes |
| Minimum Electrode Size | Snapease: 0.79in²(5.1cm²) (Focus 727/Respond Select) | Snapease: 0.79in²(5.1cm²) | Yes |
| Maximum RMS Current Density | 27.7mA/in² (Focus 727/Respond Select) | 27.7mA/in² | Yes |
| Maximum Phase Amplitude (1kΩ load) | 100mA at 1kΩ (Focus 727/Respond Select) | 100mA at 1kΩ | Yes |
| Maximum Power Density | 607 mW/in² (Focus 727/Respond Select) | 607 mW/in² | Yes |
| Phase Duration Range | 300 µsec (Focus 727/Respond Select) | 300 µsec | Yes |
| Interface Interval | 500 µsec (Focus 727); 30 µsec (Respond Select) | 500 µsec (matches Focus 727) | Yes |
| Maximum Enclosure Leakage Current | 100μΑ (Focus 727/Respond Select) | 100μΑ | Yes |
| Automatic Overload Trip | NA (Focus 727/Respond Select) | NA | Yes |
| Automatic No Load Trip | NA (Focus 727/Respond Select) | NA | Yes |
| Patient Override Control | NA (Focus 727/Respond Select) | NA | Yes |
| Max. Patient Leakage Current | 100μΑ (Focus 727/Respond Select) | 100μΑ | Yes |
| Output Indicator | YES (Focus 727/Respond Select) | YES | Yes |
| Low Battery Indicator | YES (Focus 727/Respond Select) | YES | Yes |
| Size | 3.7x2.5x0.84 (Focus 727); 6x3.58x1.38 (Respond Select) | 3.7x2.5x0.84 (matches Focus 727) | Yes |
| Weight | 145 gm with battery (Focus 727); 9.3 oz w/o battery (Respond Select) | 145 gm with battery (matches Focus 727) | Yes |
| Power Source | 9 V Alkaline Battery (Focus 727/Respond Select) | 9 V Alkaline Battery | Yes |
| Controller | Microprocessor, masked (Focus 727); Application Specific Integrated Circuit (Respond Select) | Microprocessor, masked (matches Focus 727) | Yes |
| Housing Material | ABS Plastic (Focus 727/Respond Select) | ABS Plastic | Yes |
| Indications for Use (TENS) | Symptomatic relief and management of chronic, intractable pain; Adjunctive treatment for post-surgical and post-trauma acute pain (Focus 727) | Present | Yes |
| Indications for Use (NMES/NMS) | Relaxation of muscle spasm; Prevention or retardation of disuse atrophy; Increasing local blood circulation; Muscle re-education; Immediate post-surgical stimulation of calf muscles to prevent venous thrombosis; Maintaining or increasing range of motion (Focus 727/Respond Select) | Present | Yes |
| Indications for Use (FES) | Not explicitly stated for Focus 727, but present for Respond Select (stimulation of muscles in leg and ankle of partially paralyzed patients for foot flexion to improve gait) | New indication for use aligned with Respond Select - Stimulation of the muscles in the leg and ankle of partially paralyzed patients to provide flexion of the foot and thus improve the patient's gait. This new indication is supported by the fact that the Focus 795's specifications are similar enough to the Respond Select to be considered equivalent. | Yes |
2. Sample Size Used for the Test Set and Data Provenance
The document does not describe a clinical test set in the traditional sense of patient data. The "study" here is a technical comparison for substantial equivalence.
- Sample Size for Test Set: Not applicable. The evaluation is based on comparing the technical specifications of the new device (Focus 795) to two predicate devices (Focus 727 and Respond Select).
- Data Provenance: Not applicable. No patient data or clinical trial data is mentioned. The data provenance is from the design and manufacturing specifications of the devices themselves. The country of origin of the data is implied to be internal company documentation from Empi, Inc. The evaluation is essentially a retrospective comparison of existing product specifications.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications
- Number of Experts: Not explicitly stated as being used to establish ground truth for a test set. The "ground truth" for this submission is based on the established technical specifications and performance of the predicate devices.
- Qualifications of Experts: The summary implies that engineering and regulatory personnel within Empi, Inc., were responsible for the product verification and validation and the comparison analysis. Specific qualifications are not provided, but it would typically involve engineers with expertise in medical device design, electrical engineering, and regulatory affairs.
4. Adjudication Method for the Test Set
- Adjudication method: Not applicable. There was no clinical test set requiring adjudication. The 'adjudication' was an internal comparison of technical specifications against established safety and performance standards for similar devices.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done
- MRMC Study: No. The provided information does not mention any MRMC study. This submission is for a new version of an electrical stimulator, and the approval is based on substantial equivalence to existing devices through a comparison of technical specifications and indications for use, not a clinical effectiveness study involving human readers.
- Effect Size of Human Readers with/without AI: Not applicable, as no MRMC study or AI component is mentioned.
6. If a Standalone (Algorithm Only Without Human-in-the-Loop Performance) Was Done
- Standalone Study: No. This device is an electrical stimulator, not an AI/algorithm-based diagnostic or therapeutic system. Its functionality is direct electrical stimulation controlled by pre-programmed settings, and its performance is assessed against electrical and mechanical specifications, not an algorithm's standalone accuracy.
7. The Type of Ground Truth Used
- Type of Ground Truth: The "ground truth" in this context is the established safety and performance specifications of the predicate devices (Empi Focus Model 727 and Empi Respond Select), as well as compliance with relevant industry standards (AAMI/ANSI NS4-1985, IEC 601-2-10, IEC 601-1-2). The functional testing performed against product specifications is considered the demonstration that the new device meets these established benchmarks.
8. The Sample Size for the Training Set
- Sample Size for Training Set: Not applicable. This is not an AI/machine learning device submission. The device is a hardware product with fixed firmware logic. There is no concept of a "training set" in this context.
9. How the Ground Truth for the Training Set Was Established
- Ground Truth for Training Set: Not applicable, as there is no training set for this type of device.
§ 882.5890 Transcutaneous electrical nerve stimulator for pain relief.
(a)
Identification. A transcutaneous electrical nerve stimulator for pain relief is a device used to apply an electrical current to electrodes on a patient's skin to treat pain.(b)
Classification. Class II (performance standards).