StimSox(TM) System

K151922 · Stimmed, LLC · IPF · Apr 15, 2016 · Physical Medicine

Device Facts

• Record ID: K151922
• Device Name: StimSox(TM) System
• Applicant: Stimmed, LLC
• Product Code: IPF · Physical Medicine
• Decision Date: Apr 15, 2016
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 890.5850
• Device Class: Class 2
• Attributes: Therapeutic

Intended Use

To temporarily increase local blood circulation in healthy leg muscles.

Device Story

StimSox™ System is a battery-powered electrical muscle stimulator (NMES) designed for use in healthcare facilities or home settings under medical practitioner guidance. The system consists of a stimulator unit, disposable gel electrodes, and specialized foot boots. The stimulator delivers a biphasic electrical waveform to the plantar muscles of the foot via self-adhering gel electrodes. The device is worn during periods of immobility or normal daily activity (excluding bathing or driving). The stimulator features a simple user interface with three buttons and a timed autolock to prevent inadvertent stimulation changes. By stimulating the foot muscles, the device aims to increase venous femoral and popliteal blood flow, potentially benefiting patients by improving local circulation. Healthcare providers prescribe the device for a typical duration of 10–14 days. The output is controlled by embedded firmware, and the device includes automatic overload and no-load trip safety features.

Clinical Evidence

No clinical trials were conducted for this specific 510(k). Evidence relies on bench testing, including electrical safety and EMC testing (IEC 60601 series), biocompatibility testing (ISO 10993 for cytotoxicity, irritation, and sensitization), and software verification. Literature (Kaplan et al., 2002) is cited to support the efficacy of foot-based electrical stimulation for increasing venous blood flow compared to calf stimulation.

Technological Characteristics

Battery-powered (3x AAA) biphasic electrical stimulator. Patient-contacting materials: medical-grade 100% Nylon fabric, polyester foam core, nylon tricot backing, and commercially cleared gel electrodes (ISO 10993 compliant). Dimensions: 3.62x2.87x1.10 inches. Weight: 102.55g. Connectivity: None. Software: Embedded firmware on a microcontroller, real-time event-driven loop. Safety features: Timed autolock, automatic overload/no-load trip, automatic shut-off.

Indications for Use

Indicated for temporary increase of local blood circulation in healthy leg muscles.

Regulatory Classification

Identification

A powered muscle stimulator is an electrically powered device intended for medical purposes that repeatedly contracts muscles by passing electrical currents through electrodes contacting the affected body area.

Predicate Devices

• AMD 6605 TENS/NMES Stimulator (K092990)

Submission Summary (Full Text)

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Food and Drug Administration 10903 New Hampshire Avenue Document Control Center - WO66-G609 Silver Spring, MD 20993-0002

April 15, 2016

StimMed. LLC % Marlene Wright Barton President Wright Regulatory Consulting, LLC 3900 Galt Ocean Drive, Apt. 2501 Ft Lauderdale, Florida 33308

Re: K151922

Trade/Device Name: StimSox™ System Regulation Number: 21 CFR 890.5850 Regulation Name: Powered muscle stimulator Regulatory Class: Class II Product Code: IPF Dated: April 11, 2016 Received: April 12, 2016

Dear Ms. Barton:

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 (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. 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.

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

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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 devicerelated adverse events) (21 CFR 803); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820); and if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.

If you desire specific advice for your device on our labeling regulation (21 CFR Part 801), please contact the Division of Industry and Consumer Education at its toll-free number [phone] or [phone] or at its Internet address

http://www.fda.gov/MedicalDevices/ResourcesforYou/Industry/default.htm. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR Part 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to

http://www.fda.gov/MedicalDevices/Safety/ReportaProblem/default.htm for the CDRH's Office of Surveillance and Biometrics/Division of Postmarket Surveillance.

You may obtain other general information on your responsibilities under the Act from the Division of Industry and Consumer Education at its toll-free number [phone] or [phone] or at its Internet address

http://www.fda.gov/MedicalDevices/ResourcesforYou/Industry/default.htm.

Sincerely yours,

# Michael J. Hoffmann -A

- for Carlos L. Peña, PhD, MS Director Division of Neurological and Physical Medicine Devices Office of Device Evaluation Center for Devices and Radiological Health
Enclosure

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# Indications for Use

510(k) Number (if known) K151922

Device Name StimSox(TM) System

| Indications for Use (Describe) |
|-------------------------------------------------------------------------|
| To temporarily increase local blood circulation in healthy leg muscles. |

| Type of Use ( <i>Select one or both, as applicable</i> ) |
|----------------------------------------------------------|
|----------------------------------------------------------|

X Prescription Use (Part 21 CFR 801 Subpart D)

| Over-The-Counter Use (21 CFR 801 Subpart C)

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# 510(k) Summary StimSox™ System

#### I. SUBMITTER:

StimMed LLC

388 Evans Street Williamsville, New York 14221

Phone: [phone] Fax: [phone]

| Contact Person: | Robert E. Kaplan, MD |
|-----------------|-------------------------|
| | President, StimMed LLC |
| | 388 Evans Street |
| | Williamsville, NY 14221 |
| | Fax: [phone] |
| | [e-mail] |

Date Prepared: April 13, 2016

#### II. DEVICE

Name of Device: StimSox™ System Common or Usual Name: Powered Muscle Stimulator Classification Name: Powered Muscle Stimulator (21 CFR 890.5850) Regulatory Class: Class II Product Code: IPF

#### III. PREDICATE DEVICE

Device Name: AMD 6605 TENS/NMES Stimulator 510(k) Number: K092990

To the best of our knowledge, the predicate device has not been the subject of any design related recalls.

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#### IV. DEVICE DESCRIPTION

### Device Identification

The StimSox™ System is comprised of a battery powered electrical stimulator, disposable gel electrodes, two left foot boots, two right foot boots, three AAA batteries and user manual.

### Device Characteristics

The StimSox™ Stimulator software is embedded firmware written for a microcontroller. The software in the StimSox™ Stimulator is for input controls and output display. There is no operating system. It is a real-time loop that is event driven based on the three buttons on the box.

### Environment of Use

The StimSox™ System is designed to be used in healthcare facilities or home use. The StimSox™ System is intended to be provided to the patient by a medical practitioner.

### Materials of Use

The patient contacting gel electrodes provided with the StimSox™ System are commercially cleared gel electrodes. The gel electrode materials were successfully tested per ISO 10993 for Cytotoxicity, Irritation and Sensitization. The results verified the gel electrode materials to be non-cytotoxic, non-irritating and non-sensitizing. The gel electrodes are intended to be disposed of after one use.

The material that makes up the patient contacting portion of the boot is made of medical grade100% Nylon Fabric with a Polyester Foam Core and Nylon Tricot Backing Nylon. Each boot is intended to be used for up to 7 days of use.

### Key Performance Specifications

The duration of patient use for the StimSox™ System will typically be 10 – 14 days as recommended by the ACCP (American College of Chest Physicians) or as prescribed by the patient's medical provider.

The StimSox™ Stimulator is a biphasic electrical stimulator that outputs a stimulating waveform in a prescribed pattern. The stimulator attaches to the outside of the StimSoxTM boot. The key features of this stimulator are:

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- 1. Battery powered with certified electronics.
- 2. Protected from inadvertent changes of stimulation level using timed autolock.
- 3. Simple user interface.
- Designed to be worn through all phases of immobility to full mobility 4. while performing normal daily activity, with the exception of driving or bathing.

#### INDICATIONS FOR USE V.

The StimSox™ System is indicated to temporarily increase local blood circulation in healthy leg muscles.

#### COMPARISON OF TECHNOLOGICAL CHARACTERISTICS WITH THE VI. PREDICATE DEVICE

| Comparison Feature | StimSoxTM<br>K151922 | AMD 6605<br>K092990 | Justification |
|----------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| Manufacturer | StimMed, LLC | Advantageous Medical<br>Devices, LLC | N/A |
| Indications for Use | The StimSoxTM System is indicated<br>to temporarily<br>increase local blood<br>circulation in<br>healthy leg muscles. | Indications for TENS<br>function:<br>• Symptomatic relief<br>and management of<br>chronic (long-term),<br>intractable pain and an<br>adjunctive treatment in<br>the management of<br>post-surgical pain or<br>post-traumatic acute<br>pain.<br><br>Indications for NMES<br>function:<br>• Relaxation of muscle<br>spasms<br>• Prevention or<br>retardation of disuse<br>atrophy<br>• Increasing local blood<br>circulation<br>• Muscle re-education<br>• Immediate post-<br>surgical stimulation of<br>calf muscles to prevent<br>venous thrombosis | Although the predicate has more<br>claims than the subject device, the<br>IFU of the subject device is within<br>the scope of the NMES function of<br>the predicate device. |
| Comparison Feature | StimSox™<br>K151922 | AMD 6605<br>K092990 | Justification |
| | | • Maintaining or<br>increasing range of<br>motion | |
| Electrodes | 2 | 4 (Two electrodes per<br>channel) | The number of electrodes is a<br>consequence of the number of<br>channels. |
| Electrode type | Gel Electrode<br>One 2 inch round<br>self-adhering<br>disposable and One<br>4x2 inch oval self-<br>adhering disposable<br>Comfort Gel A 032<br>Model 807 | Gel Electrode<br>2 inch round self-<br>adhering reusable<br>AmGEL AG702 (Now<br>AG735). | Comfort Gel A 032 Model 807 is<br>cleared under K072799 and<br>K101576 |
| Waveform | Biphasic | Monophasic | There is a requirement for<br>electrical stimulators to have no<br>D.C. component or a<br>rationalization why there is a D.C.<br>component (60601-2-10). The<br>StimSox™ System does not have a<br>D.C. component because it is<br>biphasic. The predicate is listed as<br>monophasic and thus must have a<br>D.C. component. |
| Maximum Intensity | 30 mA | 70 mA | The predicate supports more than<br>twice the maximum current. Based<br>on the Clinical Data Review, this<br>limited output is sufficient to meet<br>the clinical needs for the<br>StimSox™ System. |
| Current step size | 1 mA steps | 0.5 mA steps | The differences in current<br>increments, are small and do not<br>affect the desired clinical response,<br>which is a small contraction of the<br>plantar muscles of the foot. The<br>StimSox validation study<br>demonstrated that the 1.0mA<br>increments were safe and effective<br>in achieving the desired clinical<br>response. |
| Power Source | 3 batteries type<br>AAA Non-<br>rechargeable | 4 batteries type AAA<br>alkaline or rechargeable<br>Ni MH | The line isolation of the AMD<br>device is for units that also plug in.<br>This difference is not significant as<br>it does not affect the effectiveness<br>or safety of the device as the<br>StimSox™ System will not need<br>the plug in feature. |
| Method of Line Current<br>Isolation | Not Applicable | Unknown | The StimSox™ System is battery<br>powered. |
| Patient Leakage Current: | Not Applicable | Not Applicable | There is no patient leakage because<br>the StimSox stimulator is battery |
| Normal Condition | | | powered. |
| Comparison Feature | StimSox™<br>K151922 | AMD 6605<br>K092990 | Justification |
| -Single Fault Condition | Not Applicable | Not Applicable | |
| Number of Output Modes | One | Three | The predicate device is indicated<br>for more uses than the StimSox™ System. |
| Number of Output Channels | One | Two | The number of channels is less on<br>the StimSox™ System because it<br>has reduced functionality when<br>compared to the predicate. |
| -Synchronous or<br>Alternating | Not Applicable | Unknown | |
| -Method of Channel<br>Isolation | Not Applicable | Unknown | |
| Regulated Current or<br>Regulated Voltage | Current | Current | Same |
| Software/Firmware/<br>Microprocessor Control | Yes | Yes | Same |
| Automatic Overload Trip | Yes | Unknown | This difference has no effect on the<br>safety and effectiveness of the<br>device. |
| Automatic No-Load Trip | Yes | Unknown | This difference has no effect on the<br>safety and effectiveness of the<br>device. |
| Automatic Shut Off | Yes | Yes | Same |
| Patient Override Control | No | Unknown | The patient can remove the<br>StimSox stimulator or turn it<br>down. |
| Indicator Display: | | | The StimSox User Manual<br>instructs the user to change the<br>batteries. Not including a low |
| -On/Off Status | Yes | Yes | battery indicator will not affect the |
| -Low Battery | No | Yes | Safety or Effectiveness of the<br>stimulator. |
| -Voltage/Current Level | Yes | Yes | |
| Timer Range (minutes) | N/A | 0 to 90 | The StimSox device is continuous |
| Compliance with<br>Standards | ISO 10993-1<br>ISO10993-10<br>ISO 10993-12<br>IEC 60601-1-<br>6/A1:2013<br>IEC 62366/A1:2014<br>IEC 60602-1-<br>11:2010<br>IEC 60601-2-<br>10:2012<br>IEC 60601-1-2:2007<br>(Ed. 3.0)<br>IEC 60602-2-10:<br>2012 | ISO 10993-1<br>ISO 10993-12<br>ISO 10993-10<br>IEC 60601-<br>1:1988+A1:1991+A2:1<br>995<br>IEC 60601+1-<br>2:2001/A:1:2004<br>IEC 60601-14:2000<br>IEC 60601-1-6;2004 | The standards applied to the<br>StimSox™ System are the more<br>recent versions of the predicate. |
| Comparison Feature | StimSox™<br>K151922 | AMD 6605<br>K092990 | Justification |
| Compliance with 21<br>CFR 898 | N/A | Unknown | The design of the StimSox™<br>System does not include lead<br>wires. |
| Weight | 102.55g with<br>batteries | 115g with batteries | This difference has no effect on the<br>Safety or Effectiveness of the<br>device. |
| Dimensions (inches)<br>[W x H x D] | 3.62x2.87x1.10 | 5.55x2.48x0.70 | This difference has no effect on the<br>Safety or Effectiveness of the<br>device. |
| Housing Materials and<br>Construction | Plastic Enclosure | Plastic Enclosure | Same |
| Keyboard lock | Automatic | Automatic | Same |
| Programs | 1 preset | 10 preset and 10 user<br>adjustable | The predicate device includes more<br>indications for use. |
| Time of treatment | 4-18 hours | Treatment time with<br>auto shut off | The StimSox design is a simpler<br>device with a specific indication of<br>only the foot muscles. The<br>predicate is a general use device<br>that can be used on various<br>voluntary muscles. |

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### Electrode placement differences:

The predicate electrodes are placed on the calf muscles while the subject device electrodes are placed on the foot. However, in one study (Thrombosis and Haemostasis. Kaplan RE et al., Throm Haemost 2002;88:2004), stimulation of the foot vs. stimulation of the calf muscles were compared. It was found that the electrodes on the foot were more comfortable and increased the venous femoral and popliteal blood flow for both calf and plantar muscles. This study was not conducted with the predicate, however, it serves as a rationale that subject device can be atleast as safe and effective as the predicate device given similar parameters of operation.

#### Similarities:

Both the StimSox™ System and the predicate device have the following similarities:

- Use commercially available gel electrodes ●
- Battery operated (Direct Current (DC)) ●
- Regulated current ●
- Include an indicator display ●
- Provide preset programs ●
- Include continuous treatment time ●

### Conclusion

The StimSox™ stimulator has the same technological characteristics as the predicate just fewer options for treatment programming as it is designed for NMES and the

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predicate is 510 (k) cleared for TENS and NMES. These differences do not raise any additional risks of safety or effectiveness.

#### VII. PERFORMANCE DATA

The following performance data were provided in support of the substantial equivalence determination:

- Risk Analysis results demonstrate acceptable potential and mitigated hazards. ●
- Electrical Safety and Electromagnetic Compatibility (EMC)
- o IEC 60601-1-6/A1:2013
- IEC 62366/A1:2014 O
- IEC 60602-1-11:2010 o
- IEC 60601-1-2:2007 (Ed. 3.0) о
- o IEC 60601-2-10: 2012
- Biocompatibility for Gel Electrodes ●
- o Sensitization
- o Irritation
- o Cytotoxicity
- Software Verification

The data provided demonstrates that the StimSox™ is substantially equivalent to its predicate, and raises no new safety or effectiveness issues.

## VIII. OVERALL CONCLUSIONS

The performance data provide evidence that the StimSox™ System will perform as intended for the specified use conditions. The StimSox™ System is designed and verified for performance and safety. The performance of the StimSox™ System is determined to be substantially equivalent in indications, technical functions and operation to the predicate device. The Risk Analysis does not demonstrate any design or safety concerns.