StimSox(TM) System

K171071 · Stimmed, LLC · IPF · Aug 9, 2017 · Physical Medicine

Device Facts

• Record ID: K171071
• Device Name: StimSox(TM) System
• Applicant: Stimmed, LLC
• Product Code: IPF · Physical Medicine
• Decision Date: Aug 9, 2017
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 890.5850
• Device Class: Class 2
• Attributes: Therapeutic

Intended Use

The StimSox™ System is indicated to temporarily increase local blood circulation in healthy leg muscles and immediate post-surgical stimulation of calf muscles to prevent venous thrombosis.

Device Story

StimSox™ System is a battery-powered external electrical muscle stimulator; comprises stimulator unit, disposable gel electrodes, and foot boots. Operates by generating biphasic square wave electrical signals; delivered via surface electrodes to foot muscles; induces muscle contraction; increases popliteal and femoral venous blood flow; reduces venous thrombosis risk. Designed for healthcare facility or home use; provided to patient by medical practitioner. User interface includes three buttons; stimulator attaches to boot exterior. Healthcare providers use device to provide prophylactic stimulation; patients wear device during immobility. Benefits include non-invasive venous stasis reduction and DVT prophylaxis. Software controls input/output; features auto-lock for stimulation levels; automatic shut-off; low battery indicator.

Clinical Evidence

No new clinical trials conducted. Evidence relies on peer-reviewed literature (Czyrny et al. 2010; Kaplan et al. 2002) supporting safety and efficacy of electrical foot stimulation for increasing venous blood flow and DVT prophylaxis. Bench testing included electrical safety (IEC 60601 series), EMC (EN 60601-1-2), and biocompatibility (ISO 10993) for gel electrodes.

Technological Characteristics

Biphasic electrical stimulator; battery-powered (3x AAA). Materials: medical grade 100% Nylon fabric, polyester foam core, nylon tricot backing. Output: 50Hz frequency, 150μS pulse width, rectangular waveform. Connectivity: standalone. Software: embedded firmware, real-time event-driven loop, no OS. Standards: ISO 10993-1/10/12, IEC 60601-1-6, IEC 62366, IEC 60601-2-10, EN 60601-1-2.

Indications for Use

Indicated for healthy individuals to temporarily increase local blood circulation in leg muscles and for immediate post-surgical stimulation of calf muscles to prevent venous thrombosis.

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

• Actegy's Revitive IX (K123354)
• StimSox™ System (K151922)

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

August 9, 2017

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

Re: K171071

Trade/Device Name: StimSox™ System Regulation Number: 21 CFR 890.5850 Regulation Name: Powered Muscle Stimulator Regulatory Class: Class II Product Code: IPF Dated: August 7. 2017 Received: August 8, 2017

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

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or any Federal statutes and regulations administered by other Federal agencies. You must comply 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 (OS) 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.

# Michael J. Hoffmann -S

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) K171071

Device Name StimSox™ System

Indications for Use (Describe)

The StimSox™ System is indicated to temporarily increase local blood circulation in healthy leg muscles and immediate post-surgical stimulation of calf muscles to prevent venous thrombosis.

Type of Use (Select one or both, as applicable)

| <span></span> <span></span> Prescription Use (Part 21 CFR 801 Subpart D) |
|--------------------------------------------------------------------------|
| <span></span> Over-The-Counter Use (21 CFR 801 Subpart C) |

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Image /page/3/Picture/0 description: The image shows the logo for "STIMMED". The logo consists of a blue hexagon with a white plus sign inside, followed by the word "STIMMED" in a stylized font. The "S", "T", "I", and "M" are in a dark gray color, while the "E", "D" are in a dark blue color.

# 510(k) Summary

#### I. SUBMITTER:

StimMed LLC 388 Evans Street Williamsville, New York 14221

Phone: [phone] Fax: [phone]

Contact Person: Peter G. Demakos, P.E. CEO, StimMed LLC 388 Evans Street Williamsville, NY 14221 Cell: 716-435-6736 Fax: [phone] [e-mail]

Date Prepared: August 9, 2017

#### II. DEVICE

Name of Device: StimSox™ System Common or Usual Name: Powered Muscle Stimulator Classification Name: Powered Muscle Stimulator for Re-education of Muscles (21 CFR 870.5850) Regulatory Class: Class II Product Code: IPF

#### III. PREDICATE DEVICES

Device Name (Primary): Actegy's Revitive IX 510(k) Number: K123354

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Device Name (Secondary): StimSox™ System 510(k) Number: K151922

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

#### DEVICE DESCRIPTION IV.

### a. Device Identification

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

## b. 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.

### c. 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.

## d. Principle of Operation

The StimSox™ System is a powered external stimulator. An electrical signal generator produces a square wave pattern of variable frequency, duration, intensity, ramp time, and stimulation on-off cycle. Surface electrodes are positioned over the foot muscles and are attached to the stimulator. The stimulator is programmed in a manner to stimulate the foot muscles. Stimulation can lead to a temporary increase in the popliteal and femoral venous blood flow. This increase in blood flow may help reduce the risk of venous thrombosis.

## e. 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 (24 hours).

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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.

#### f. Key Performance Specifications

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 StimSox™ boot. The key features of this stimulator are:

- 1. Battery powered with certified electronics.
- Protected from inadvertent changes of stimulation level using timed auto-2. lock.
- Simple user interface. 3.
- 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.

#### V. INDICATIONS FOR USE

The StimSox™ System is indicated to temporarily increase local blood circulation in healthy leg muscles and immediate post-surgical stimulation of calf muscles to prevent venous thrombosis.

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

| Comparison Feature | Actegy's Revitive IX (Primary Predicate) | StimSoxTM (Secondary Predicate) | StimSoxTM (Subject of this 510(K)) |
|----------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| 510(k) Number | K123354 | K151922 | K171071 |
| Manufacturer | Actegy Ltd. | StimMed, LLC | StimMed, LLC |
| Indications for Use | • Relaxation of muscle spasms;<br>• Prevention or retardation of disuse atrophy;<br>• Increasing local blood circulation;<br>• Muscle re-education;<br>• Immediate post-surgical stimulation of | To temporarily increase local blood circulation in healthy leg muscles. | • To temporarily increase local blood circulation in healthy leg muscles; and<br>• Immediate post-surgical stimulation of calf muscles to prevent venous thrombosis. |
| Comparison Feature | Actegy's Revitive<br>IX (Primary<br>Predicate) | StimSox™<br>(Secondary<br>Predicate) | StimSox™ (Subject of<br>this 510(K)) |
| | calf muscles to<br>prevent venous<br>thrombosis;<br>and<br>• Maintaining or<br>increasing range of<br>motion. | | |
| Mode of Stimulation | Moving venous<br>blood from the veins<br>in the foot<br>anterograde (forward<br>or proximally) up the<br>lower extremity to<br>prevent stagnation or<br>pooling of venous<br>blood flow in<br>calf veins | Moving venous blood<br>from the veins in the foot<br>anterograde (forward or<br>proximally) up the lower<br>extremity to prevent<br>stagnation or pooling of<br>venous<br>blood flow in calf<br>veins | Moving venous blood<br>from the veins in the<br>foot anterograde<br>(forward or proximally)<br>up the lower extremity<br>to prevent stagnation or<br>pooling of venous<br>blood flow in calf<br>veins |
| Technology | Electrical stimulation | Electrical stimulation | Electrical stimulation |
| Power Source | 3.6Vdc Lithium Ion<br>Polymer<br>rechargeable battery | 3 batteries type AAA<br>Non-recharge | 3 batteries type AAA<br>Non-rechargeable |
| Method of Line<br>Current<br>Isolation | Transformer isolation | Not Applicable | Not Applicable |
| Patient<br>Leakage<br>Current: | | Not Applicable | Not Applicable |
| -Normal Condition | Patient leakage: 6.21<br>μA max, Enclosure<br>leakage : 5.99 μA | | |
| -Single<br>Fault<br>Condition | Patient leakage: 8.36<br>μA max, Enclosure<br>leakage: 7:95 μA<br>max | | |
| Number of Output<br>Modes | One | One | One |
| Number of<br>Output Channels | 2 (1 for sole, 1<br>for body pads) | One | One |
| -Synchronous<br>or Alternating | Alternating | Not Applicable Not | Not Applicable |
| -Method of<br>Channel Isolation | Transformer | Applicable | Not Applicable |
| Comparison Feature | Actegy's Revitive | StimSox™ | StimSox™ (Subject of |
| | IX (Primary<br>Predicate) | (Secondary<br>Predicate) | this 510(K)) |
| Regulated Current<br>or Regulated<br>Voltage | Regulated up to 150V | Current | Current |
| Software / Firmware<br>/ Microprocessor<br>Control | Yes | Yes | Yes |
| Automatic Overload<br>Trip | No | Yes | Yes |
| Automatic No-Load<br>Trip | No | Yes | Yes |
| Automatic Shut Off | Yes | Yes | Yes |
| Patient Override<br>Control | Yes | No | No |
| Indicator Display: | | | |
| -On/Off Status | Yes | Yes | Yes |
| -Low Battery | N/A | Yes | Yes |
| -Voltage/Current<br>Level | Yes | Yes | Yes |
| Timer Range<br>(minutes) | 1 - 60 minutes | N/A | N/A |
| Compliance with | EMDD (93/42EEC), | ISO 10993-1 | ISO 10993-1 |
| voluntary standards | EN60601-1-2:2007 | ISO10993-12 | ISO10993-12 |
| | | ISO 10993-10 | ISO 10993-10 |
| | | IEC 60601-1-6/A1:2013 | IEC 606011-6/A1:2013 |
| | | IEC 62366/A1:2014 | IEC 62366/A1:2014 |
| | | IEC 60602-1-11:2010 | IEC 60602-1-11:2010 |
| | | IEC 60601-2-10:2012 | IEC 60601-2-10:2012 |
| | | EN 60601-1-2:2007 | EN 60601-1-2:2007 |
| | | (Ed. 3.0) | (Ed. 3.0) |
| | | EN 60602-2-10: 2012 | EN 60602-2-10: 2012 |
| Compliance with 21<br>CFR 898 | Complies | Not Applicable | Not Applicable |
| Weight | 1725g (not including | 102.55g with | 102.55g with batteries |
| | the PSU) | batteries | |
| Comparison Feature | Actegy's Revitive<br>IX (Primary<br>Predicate) | StimSox TM<br>(Secondary<br>Predicate) | StimSox TM (Subject of<br>this 510(K)) |
| Dimensions (inches)<br>[W x H x D] | 360mm x 75mm<br>overall height | 3.62x2.87x1.10 | 3.62x2.87x1.10 |
| Housing Materials<br>and Construction | Casing/body ABS,<br>footpads NBR | Plastic Enclosure | Plastic Enclosure |

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#### COMPARISON OF OUTPUT SPECIFICATIONS VII.

| Output Specifications | Actegy's Revitive<br>IX (Primary<br>Predicate) | StimSoxTM<br>(Secondary<br>Predicate) | StimSoxTM (Subject of<br>this 510(K)) |
|--------------------------------------------------------------|------------------------------------------------|-----------------------------------------|----------------------------------------|
| Waveform (e.g.,<br>pulsed monophasic,<br>biphasic) | monophasic | diphasic | diphasic |
| Shape (e.g.,<br>rectangular, spike,<br>rectified sinusoidal) | rectangular | rectangular | rectangular |
| Maximum Output<br>Voltage (specify<br>units) (± 10%) | 35V @ 500 Ω<br>103V @2 kΩ<br>135V @ 10 kΩ | 15V @500 Ω<br>60V @ 2 kΩ<br>133V @ 10kΩ | 15V @500 Ω<br>60V @ 2 kΩ<br>133V @10kΩ |
| Maximum Output<br>Current (specify<br>units) (±10%) | 70mA@ 500 Ω<br>52mA@2kΩ<br>14mA@10kΩ | 30mA@500Ω<br>30mA@2kΩ<br>13.3mA@10kΩ | 30mA@500Ω<br>30mA@2kΩ<br>13.3mA@10kΩ |
| Pulse Width (specify<br>units) | Not disclosed | 50μS | 150μS |
| Frequency (Hz) | Not disclosed | 50Hz | 50Hz |
| For interferential<br>modes only: | Not disclosed | N/A | N/A |
| Beat Frequency (Hz) | N/A | Yes | Yes |
| For multiphasic<br>waveforms only:<br>Symmetrical phases? | N/A | 300μS | 300μS |

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| Output Specifications | Actegy's Revitive | StimSoxTM | StimSox™ (Subject of |
|---------------------------|-------------------|------------|----------------------|
| | IX (Primary | (Secondary | this 510(K)) |
| | Predicate) | Predicate) | |
| Net Charge (µC per | 0.004@500Ω | 4.5 @500 Ω | 4.5 @500 Ω |
| pulse) | | | |
| (If zero, state method of | | | |
| achieving zero net | | | |
| charge) | | | |
| Maximum Phase | 52@500Ω | 5400@500Ω | 5400@500Ω |
| Charge, (uC) | | | |
| Maximum Current | 0.031 @500Ω | 1.53@500Ω | 1.53@500Ω |
| Density, (mA/cm2) | | | |
| Maximum Power | 0.79@500Ω | 0.023@500Ω | 0.023@500Ω |
| Density, (W/cm2) | | | |
| (using smallest | | | |
| electrode conductive | | | |
| surface area) | | | |
| Burst Mode (i.e., | | | |
| pulse trains) | | | |
| Pulses per burst<br>a. | 195 – 1092 | 600 | 600 |
| Bursts per second<br>b. | 0.11 - 0.29 | 0.0167 | 0.0167 |
| Burst duration<br>C. | 1.91 - 8.35 | 12 | 12 |
| (seconds) | | | |
| Duty Cycle [Line<br>d. | 0.56 - 0.89 | 0.20 | 0.20 |
| (b) x Line (c)] | | | |
| ON Time (seconds) | 1.90 - 8.40 | 12 | 12 |
| OFF Time (seconds) | 1.00 - 1.50 | 48 | 48 |

## VIII. CLINICAL EVALUATION

Peer-reviewed journal articles were reviewed to support the safety and efficacy of the StimSox™ technology for the expanded indication of immediate post-surgical stimulation of calf muscles to prevent venous thrombosis. The articles are provided along with a summary below:

- 1. James J. Czyrny, Robert E. Kaplan, Gregory E. Wilding, Christopher H. Purdy, and Jack Hirsh. Electrical Foot Stimulation: A Potential New Method of Deep Venous Thrombosis Prophylaxis. Vascular, Vol. 18, No. 1, pp. 20-27, 2010.
Czyrny JJ, et al. concluded that short-term electrical foot stimulation is at least as effective as knee-high intermittent pneumatic compression in increasing popliteal and femoral blood flow velocity.

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- 2. Robert E. Kaplan, James J. Czyrny, Tat S. Fung, John D. Unsworth, Jack Hirsh. Electrical Foot Stimulation and Implications for the Prevention of Venous Thromboembolic Disease. Thromb Haemost 2002; 88:200-4.
Kaplan RE, et al. concluded that mild electrical stimulation of the feet, as well as the calf, is a safe effective and convenient method for counteracting venous stasis and therefore has the potential to reduce the risk of deep vein thrombosis and pulmonary embolism for subjects who are immobilized.

## Overall Conclusion

These studies used comparable stimulation parameters as the StimSox System and demonstrated that stimulation on sole of the foot can lead to a temporary increase in local blood circulation in calf muscles. This increase in blood flow may help reduce the risk of venous thrombosis.

#### IX. 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) ●
- IEC 60601-1-6/A1:2013 o
- IEC 62366/A1:2014 o
- IEC 60602-1-11:2010 O
- EN 60601-1-2:2007 (Ed. 3.0) O
- EN 60601-2-10: 2012 о
- Biocompatibility for Gel Electrodes .
- Sensitization o
- Irritation O
- o Cytotoxicity
- Software Verification ●

The device is identical in design compared to the secondary predicate device K151922. The electrical safety, EMC, biocompatibility, and software were leveraged from that submission. The data provided demonstrates that the StimSox™ System is substantially equivalent to its predicate, and raises no new safety or effectiveness issues.

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#### X. CONCLUSION

The performance data and Risk Analysis support the safety of the device and the software verification and validation provide evidence that the StimSox™ System will perform as intended for the specified use conditions. The StimSox™ 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.