(121 days)
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.
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.
The provided document is a 510(k) premarket notification for the StimSox™ System. It focuses on demonstrating substantial equivalence to predicate devices, rather than presenting a standalone clinical study with detailed acceptance criteria and performance data for a new device.
Therefore, the information requested regarding acceptance criteria, study design, sample sizes, expert ground truth, adjudication methods, MRMC studies, and ground truth establishment for training sets is largely Not Applicable or Not Provided in this type of submission.
Here's a breakdown based on the available information:
1. Table of Acceptance Criteria and Reported Device Performance
This document does not present a table of specific acceptance criteria in numerical terms (e.g., sensitivity, specificity, or improvement percentage) for a clinical outcome, nor does it explicitly report the StimSox™ System's performance against such criteria. The "performance data" mentioned focuses on safety, electrical standards, and biocompatibility, which are part of demonstrating substantial equivalence, not clinical effectiveness in the way a diagnostic AI might be evaluated.
The relevant section, "VIII. CLINICAL EVALUATION," discusses peer-reviewed journal articles for the predicate technology, not a direct study of the StimSox™ System itself. The overall conclusion states that these studies "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." This reflects the claimed benefit of the technology, broadly, rather than specific performance metrics for this device against pre-defined acceptance criteria.
2. Sample Sizes used for the test set and data provenance
- Sample Size for Test Set: Not applicable / Not provided. The submission refers to existing peer-reviewed articles on the technology itself, not a new clinical trial for the StimSox™ System with a "test set."
- Data Provenance: The document refers to peer-reviewed journal articles (Czyrny JJ, et al. 2010; Kaplan RE, et al. 2002). Specific details about the country of origin of the data or whether they were retrospective or prospective studies are not provided within this 510(k) summary.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts
Not applicable / Not provided. This type of detail would be found in a clinical study report for a new device, which is not what this 510(k) summary contains. The "ground truth" for the claims cited from the predicate literature would be the clinical outcomes and measurements reported in those studies, as interpreted by the authors and peer reviewers.
4. Adjudication method for the test set
Not applicable / Not provided. As there's no "test set" for a new clinical study of the StimSox™ System in this document, no adjudication method is described.
5. If a multi reader multi case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance
Not applicable. The StimSox™ System is a powered muscle stimulator, not an AI-assisted diagnostic tool for "human readers." Therefore, an MRMC comparative effectiveness study is irrelevant to this device.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
Not applicable. The StimSox™ System is a physical medical device, not a standalone algorithm. Its performance is evaluated through electrical safety, biocompatibility, and by referencing the clinical effectiveness of similar technology as demonstrated in published literature.
7. The type of ground truth used
The "ground truth" for the clinical claims (increased local blood circulation, prevention of venous thrombosis) is based on the findings of peer-reviewed scientific literature related to electrical foot stimulation. These studies would have used clinical measures and outcomes data to establish their findings. For example, Czyrny JJ, et al. concluded "electrical foot stimulation is at least as effective as knee-high intermittent pneumatic compression in increasing popliteal and femoral blood flow velocity," which implies measurements of blood flow velocity as the basis for their conclusions.
8. The sample size for the training set
Not applicable / Not provided. The StimSox™ System is not an AI/ML algorithm that requires a "training set" in the context of machine learning. The term "training set" is not relevant to its development as described here.
9. How the ground truth for the training set was established
Not applicable. See point 8.
{0}------------------------------------------------
Image /page/0/Picture/2 description: The image shows the logo for the U.S. Department of Health & Human Services. The logo is a circular seal with the words "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" around the perimeter. Inside the circle is a stylized image of three human profiles facing to the right, one behind the other.
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
{1}------------------------------------------------
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 (800) 638-2041 or (301) 796-7100 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 (800) 638-2041 or (301) 796-7100 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
{2}------------------------------------------------
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)
| Prescription Use (Part 21 CFR 801 Subpart D) |
|---|
| Over-The-Counter Use (21 CFR 801 Subpart C) |
CONTINUE ON A SEPARATE PAGE IF NEEDED.
This section applies only to requirements of the Paperwork Reduction Act of 1995.
DO NOT SEND YOUR COMPLETED FORM TO THE PRA STAFF EMAIL ADDRESS BELOW.
The burden time for this collection of information is estimated to average 79 hours per response, including the time to review instructions, search existing data sources, gather and maintain the data needed and complete and review the collection of information. Send comments regarding this burden estimate or any other aspect of this information collection, including suggestions for reducing this burden, to:
Department of Health and Human Services Food and Drug Administration Office of Chief Information Officer Paperwork Reduction Act (PRA) Staff PRAStaff@fda.hhs.gov
"An agency may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a currently valid OMB number."
{3}------------------------------------------------
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: 888-784-6633 Fax: 716-631-1273
Contact Person: Peter G. Demakos, P.E. CEO, StimMed LLC 388 Evans Street Williamsville, NY 14221 Cell: 716-435-6736 Fax: 716-631-1273 pdemakos@stimmed.com
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
{4}------------------------------------------------
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).
{5}------------------------------------------------
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:
-
- 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;• Prevention or retardation of disuse atrophy;• Increasing local blood circulation;• Muscle re-education;• 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• Immediate post-surgical stimulation of calf muscles to prevent venous thrombosis. |
| Comparison Feature | Actegy's RevitiveIX (PrimaryPredicate) | StimSox™(SecondaryPredicate) | StimSox™ (Subject ofthis 510(K)) |
| calf muscles toprevent venousthrombosis;and• Maintaining orincreasing range ofmotion. | |||
| Mode of Stimulation | Moving venousblood from the veinsin the footanterograde (forwardor proximally) up thelower extremity toprevent stagnation orpooling of venousblood flow incalf veins | Moving venous bloodfrom the veins in the footanterograde (forward orproximally) up the lowerextremity to preventstagnation or pooling ofvenousblood flow in calfveins | Moving venous bloodfrom the veins in thefoot anterograde(forward or proximally)up the lower extremityto prevent stagnation orpooling of venousblood flow in calfveins |
| Technology | Electrical stimulation | Electrical stimulation | Electrical stimulation |
| Power Source | 3.6Vdc Lithium IonPolymerrechargeable battery | 3 batteries type AAANon-recharge | 3 batteries type AAANon-rechargeable |
| Method of LineCurrentIsolation | Transformer isolation | Not Applicable | Not Applicable |
| PatientLeakageCurrent: | Not Applicable | Not Applicable | |
| -Normal Condition | Patient leakage: 6.21μA max, Enclosureleakage : 5.99 μA | ||
| -SingleFaultCondition | Patient leakage: 8.36μA max, Enclosureleakage: 7:95 μAmax | ||
| Number of OutputModes | One | One | One |
| Number ofOutput Channels | 2 (1 for sole, 1for body pads) | One | One |
| -Synchronousor Alternating | Alternating | Not Applicable Not | Not Applicable |
| -Method ofChannel Isolation | Transformer | Applicable | Not Applicable |
| Comparison Feature | Actegy's Revitive | StimSox™ | StimSox™ (Subject of |
| IX (PrimaryPredicate) | (SecondaryPredicate) | this 510(K)) | |
| Regulated Currentor RegulatedVoltage | Regulated up to 150V | Current | Current |
| Software / Firmware/ MicroprocessorControl | Yes | Yes | Yes |
| Automatic OverloadTrip | No | Yes | Yes |
| Automatic No-LoadTrip | No | Yes | Yes |
| Automatic Shut Off | Yes | Yes | Yes |
| Patient OverrideControl | Yes | No | No |
| Indicator Display: | |||
| -On/Off Status | Yes | Yes | Yes |
| -Low Battery | N/A | Yes | Yes |
| -Voltage/CurrentLevel | Yes | Yes | Yes |
| Timer Range(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 21CFR 898 | Complies | Not Applicable | Not Applicable |
| Weight | 1725g (not including | 102.55g with | 102.55g with batteries |
| the PSU) | batteries | ||
| Comparison Feature | Actegy's RevitiveIX (PrimaryPredicate) | StimSox TM(SecondaryPredicate) | StimSox TM (Subject ofthis 510(K)) |
| Dimensions (inches)[W x H x D] | 360mm x 75mmoverall height | 3.62x2.87x1.10 | 3.62x2.87x1.10 |
| Housing Materialsand Construction | Casing/body ABS,footpads NBR | Plastic Enclosure | Plastic Enclosure |
{6}------------------------------------------------
{7}------------------------------------------------
{8}------------------------------------------------
COMPARISON OF OUTPUT SPECIFICATIONS VII.
| Output Specifications | Actegy's RevitiveIX (PrimaryPredicate) | StimSoxTM(SecondaryPredicate) | StimSoxTM (Subject ofthis 510(K)) |
|---|---|---|---|
| Waveform (e.g.,pulsed monophasic,biphasic) | monophasic | diphasic | diphasic |
| Shape (e.g.,rectangular, spike,rectified sinusoidal) | rectangular | rectangular | rectangular |
| Maximum OutputVoltage (specifyunits) (± 10%) | 35V @ 500 Ω103V @2 kΩ135V @ 10 kΩ | 15V @500 Ω60V @ 2 kΩ133V @ 10kΩ | 15V @500 Ω60V @ 2 kΩ133V @10kΩ |
| Maximum OutputCurrent (specifyunits) (±10%) | 70mA@ 500 Ω52mA@2kΩ14mA@10kΩ | 30mA@500Ω30mA@2kΩ13.3mA@10kΩ | 30mA@500Ω30mA@2kΩ13.3mA@10kΩ |
| Pulse Width (specifyunits) | Not disclosed | 50μS | 150μS |
| Frequency (Hz) | Not disclosed | 50Hz | 50Hz |
| For interferentialmodes only: | Not disclosed | N/A | N/A |
| Beat Frequency (Hz) | N/A | Yes | Yes |
| For multiphasicwaveforms only:Symmetrical phases? | N/A | 300μS | 300μS |
{9}------------------------------------------------
| 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 bursta. | 195 – 1092 | 600 | 600 |
| Bursts per secondb. | 0.11 - 0.29 | 0.0167 | 0.0167 |
| Burst durationC. | 1.91 - 8.35 | 12 | 12 |
| (seconds) | |||
| Duty Cycle [Lined. | 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:
-
- 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.
- 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.
{10}------------------------------------------------
-
- 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.
- 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.
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.
{11}------------------------------------------------
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.
§ 890.5850 Powered muscle stimulator.
(a)
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.(b)
Classification. Class II (performance standards).