FOCUS MODEL 795 UNIT

K951951 · Empi · GZJ · May 17, 1996 · Neurology

Device Facts

• Record ID: K951951
• Device Name: FOCUS MODEL 795 UNIT
• Applicant: Empi
• Product Code: GZJ · Neurology
• Decision Date: May 17, 1996
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 882.5890
• Device Class: Class 2
• Attributes: Therapeutic

Intended Use

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 immediately after surgery - maintaining or increasing range of motion As a FES device, the Focus is indicated for the following condition: - 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

Device Story

Empi Focus is a dual-channel NMES/TENS/FES unit; delivers Empi Bi-Sourced® electrical stimulation via leadwires and electrodes. Device features 8 pre-programmed regimens; 2 output levels (0-40mA or 0-60mA); powered by 9V battery. Operated by clinician or patient; used for pain management, muscle rehabilitation, and gait training. Includes safety interlock preventing current delivery from 'no output' state. Output parameters (pulse width, frequency, ramp time) controlled by masked microprocessor. Healthcare providers use device to manage pain or facilitate physical therapy; output affects muscle contraction or sensory nerve stimulation to achieve therapeutic goals.

Clinical Evidence

Bench testing only. Functional testing performed against product specifications demonstrated compliance with requirements. No clinical data required for equivalence.

Technological Characteristics

Dual-channel NMES/TENS/FES; ABS plastic housing; 9V alkaline/NiCad battery power. Constant current output (100Ω-1kΩ); symmetrical/balanced asymmetrical biphasic waveforms; 300μs pulse width. Standards: AAMI/ANSI NS4-1985, IEC 601-2-10, IEC 601-1-2. Masked microprocessor control. Connectivity: Hand-held remote or heel switch accessories.

Indications for Use

Indicated for patients requiring symptomatic relief of chronic intractable pain, post-surgical/post-trauma acute pain, muscle spasm relaxation, prevention/retardation of disuse atrophy, increased local blood circulation, muscle re-education, prevention of post-surgical venous thrombosis, maintenance/increase of range of motion, and gait improvement in partially paralyzed patients via leg/ankle muscle stimulation.

Regulatory Classification

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.

Predicate Devices

• Empi Focus Model 727
• Empi Respond Select

Submission Summary (Full Text)

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K951951

# 510(K) SUMMARY OF SAFETY AND EFFECTIVENESS

May 17 1995

The assigned 510(k) number is: K951951

This summary of 510(k) safety and effectiveness information is being submitted in accordance with the requirements of SMDA 1990 and 21 CFR 807.92.

| Applicant name: | Empi, Inc. |
| --- | --- |
| Applicant address: | 5255 East River Rd.
Fridley, MN 55421 |
| Contact person: | Stacy Mattson, Regulatory Affairs Manager |
| Phone: | 612-586-7354 |
| Date Prepared: | August 21, 1995 |
| Classification Name: | Transcutaneous Electrical Nerve Stimulator (TENS)
Powered Muscle Stimulator (NMES)
External Functional Neuromuscular Stimulator (FES) |
| Common/Usual Name: | NMES/TENS/FES unit |
| Trade/Proprietary Name: | Empi Focus |
| Equivalent Devices: | Empi Focus Model 727
Empi Respond Select |

## Product Description:

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 electrode 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.

## Intended Use:

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 immediately after surgery
- maintaining or increasing range of motion

As a FES device, the Focus is indicated for the following condition:

- 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

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# Comparison of Equivalent Devices to the New Device:

The Focus Model 795 is technically identical to the Focus 727 with the exception of a change in the LED lights from red to yellow. No testing is needed to establish equivalence.

The Focus Model 795 performs identically to the Focus 727 with the exception of an added function to prevent the stimulator from delivering current from a no output condition (no battery or device is turned OFF) to a rapid increase in current (fresh battery without turning the device OFF or manually turning the potentiometer up too quickly from start up of the device). This is an added “safety” feature which is required to meet international device standards. This function does not impact the performance of the device, thus does not require clinical testing to establish equivalence.

The Focus 795 also has a new indication for use, gait training, which makes the Focus indications for use equivalent to the indications for the Respond Select. This new indication is supported by the fact that these two products’ specifications are similar enough to be considered equivalent. See the comparison chart for specification details.

# Product Verification and Validation

The functional testing that was performed and analyzed against product specifications demonstrates that the product meets requirements and is acceptable for its intended use.

# Comparison of Product Specifications

See the following chart for details on the similarities and differences of the two predicate devices and the Focus device.

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COMPARISON OF PRODUCT SPECIFICATIONS

| Product Characteristics | Focus Model 795 | Focus Model 795 | Respond Select |
| --- | --- | --- | --- |
| No. Of Output Channels | 2 | 2 | 2 |
| 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 | AAMI/ANSI NS4-1985
IEC 601-2-10
IEC 601-1-2 |
| Current Range | 0-60mA (normal)
0-100mA (high) | 0-60mA (normal)
0-100mA (high) | 0-100 mA (alkaline)
0-90 mA (NiCd) |
| Maximum Output Voltage (1kΩ load) | ± 100 V * | ± 100 V * | ± 100 V * |
| Channel Interaction | ≤ 5% | ≤ 5% | ≤ 5% |
| Pulse Width | 300μs at 50% of peak amplitude | 300μs at 50% of peak amplitude | 300μs at 50% of peak amplitude |
| Waveforms* | Symmetrical biphasic or balanced asymmetrical biphasic | Symmetrical biphasic or balanced asymmetrical biphasic | Symmetrical biphasic or balance asymmetrical biphasic |
| Zero Net DC | yes controlled by transformer | yes controlled by transformer | yes controlled by transformer |
| Maximum Phase Charge (1kΩ load) | 30μC * | 30μC * | 30μC * |
| Pulse Rates | 25, 30, 35, 45, 50, 80 Hz | 25, 30, 35, 45, 50, 80 Hz | 1-80 Hz |
| ON Times | 2.5, 5, 10, 15, 20, 25, 30, 50 sec | 2.5, 5, 10, 15, 20, 25, 30, 50 sec | 2-60 sec, adjustable |
| OFF Times | 0, 5, 10, 15, 20, 25, 30, 50 sec | 0, 5, 10, 15, 20, 25, 30, 50 sec | 2-120 sec, adjustable |
| Ramp Time | 2 sec up, fixed
2 sec down, fixed
disabled with remote switch | 2 sec up, fixed
2 sec down, fixed
disabled with the remote switch | .2 - 10 sec up, adjustable
.1 - 5 sec down, adjustable
.4 sec up for gait protocol
1 sec down for gait protocol |
| Cycling Modes | synchronous(S) or alternating(A) | synchronous(S) or alternating(A) | synchronous or asynchronous |
| Timing Control Modes | continuous, normal operation, 15 or 30min, | continuous, normal operation, 15 or 30min, | continuous, 15, 30, 60min |
| Preprogrammed Regimens | 8 | 8 | 4 |
| High Output Shutdown (Output Interlock) | NO | YES | YES |
| Waveform Change Interlock | YES | YES | YES |
| Compliance Timer | NO | NO | YES |
| Accessories | Hand Held Remote or Heel Switch | Hand Held Remote or Heel Switch | Hand Held Remote or Heel Switch |
| Output Type | constant current
100Ω - 1kΩ | constant current
100Ω - 1kΩ | constant current
100Ω - 1kΩ |
| Minimum Electrode Size | Snapease: 0.79in²(5.1cm²) | Snapease: 0.79in²(5.1cm²) | Snapease: 0.79in²(5.1cm²) |
| Maximum RMS Current Density | 27.7mA/in² * | 27.7mA/in² * | 27.7mA/in² * |
| Maximum Phase Amplitude (specify load) | 100mA at 1kΩ * | 100mA at 1kΩ * | 100mA at 1kΩ * |
| Maximum Power Density | 607 mW/in² * | 607 mW/in² * | 607 mW/in² * |

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COMPARISON OF PRODUCT SPECIFICATIONS (cont.)

| Product Characteristics | Focus Model 727 | Focus Model 795 | Respond Select |
| --- | --- | --- | --- |
| Phase Duration Range | 300 μsec | 300 μsec | 300 μsec |
| Interface Interval | 500 μsec | 500 μsec | 30 μsec |
| Maximum Enclosure Leakage Current | 100μA | 100μA | 100μA |
| Automatic Overload Trip | NA | NA | NA |
| Automatic No Load Trip | NA | NA | NA |
| Patient Override Control | NA | NA | NA |
| Max. Patient Leakage Current | 100μA | 100μA | 100μA |
| Output Indicator | YES | YES | YES |
| Low Battery Indicator | YES | YES | YES |
| Size | 3.7x2.5x0.84 | 3.7x2.5x0.84 | 6x3.58x1.38 |
| Weight | 145 gm with battery | 145 gm with battery | 9.3 oz w/o battery |
| Power Source | 9 V Alkaline Battery | 9 V Alkaline Battery | 9 V Alkaline Battery |
| Controller | Microprocessor, masked | Microprocessor, masked | Application Specific Integrated Circuit |
| Housing Material | ABS Plastic | ABS Plastic | ABS Plastic |
| Indications for Use | As a TENS device, the 727 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
• Immediate post-surgical stimulation of calf muscles to prevent venous thrombosis
• maintaining or increasing range of motion | As a TENS device, the 795 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
• Immediate post-surgical stimulation of calf muscles to prevent venous thrombosis
• maintaining or increasing range of motion
As a FES device, the Focus is indicated for the following condition:
• 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 | As a NMS/NMES device, Respond Select is indicated for the following conditions:
• 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
As a FES device, the Focus is indicated for the following condition:
• 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 |