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. 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.

AI/ML Overview

The provided text describes a 510(k) premarket notification for the StimSox™ System, a powered muscle stimulator. The document focuses on demonstrating substantial equivalence to a predicate device, the AMD 6605 TENS/NMES Stimulator.

Here's an analysis of the acceptance criteria and supporting study information, based on the provided text:

1. Table of Acceptance Criteria and Reported Device Performance

The document does not explicitly present a table of "acceptance criteria" for the StimSox™ System in terms of performance metrics like sensitivity, specificity, or AUC, as might be found for a diagnostic AI device. Instead, it demonstrates "substantial equivalence" to a predicate device by comparing technological characteristics and showing compliance with relevant safety and performance standards. The "performance" is largely demonstrated through these comparisons and a validation study mentioned for current increments.

Acceptance Criteria (Implied)	Reported Device Performance
Safety:
Biocompatibility of patient-contacting materials	Gel electrodes non-cytotoxic, non-irritating, non-sensitizing per ISO 10993. Boots made of medical grade Nylon Fabric.
Electrical Safety (IEC 60601-1-6/A1:2013, IEC 62366/A1:2014, IEC	Complied with IEC 60601-1-6/A1:2013, IEC 62366/A1:2014, IEC 60602-1-11:2010, IEC 60601-1-2:2007 (Ed. 3.0), IEC 60601-2-10: 2012.
60602-1-11:2010, IEC 60601-1-2:2007, IEC 60601-2-10: 2012)
Electromagnetic Compatibility (EMC) (IEC 60601-1-2:2007)	Complied with IEC 60601-1-2:2007 (Ed. 3.0).
Risk Analysis	Satisfactory risk analysis results demonstrating acceptable potential and mitigated hazards.
No DC component in waveform (IEC 60601-2-10)	Biphasic waveform, ensuring no DC component.
Effectiveness (Substantial Equivalence):
Ability to temporarily increase local blood circulation in healthy	Indicated to temporarily increase local blood circulation in healthy leg muscles. Clinical data review suggests limited output is sufficient. Validation study demonstrated 1.0mA increments were safe and effective in achieving a small contraction of plantar muscles and desired clinical response.
leg muscles
Performance of 1mA current steps to achieve clinical response	A validation study demonstrated that the 1.0mA increments were safe and effective in achieving the desired clinical response (small contraction of the plantar muscles of the foot).
Software Verification	Software verification provided.

2. Sample Size Used for the Test Set and Data Provenance

The document mentions a "StimSox validation study" which "demonstrated that the 1.0mA increments were safe and effective in achieving the desired clinical response." However, it does not provide specific details on the sample size used for this test set, nor the data provenance (e.g., country of origin, retrospective/prospective nature).

It also references "one study (Thrombosis and Haemostasis. Kaplan RE et al., Throm Haemost 2002;88:2004)" for electrode placement differences, stating it found foot electrodes more comfortable and effective. This study was "not conducted with the predicate," and details about its sample size or provenance are not given in the context of the StimSox validation.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts

This information is not provided in the document. The nature of the device (powered muscle stimulator) and its intended use (increasing local blood circulation) would likely involve physiological measurements rather than expert image interpretation for ground truth.

4. Adjudication Method for the Test Set

This information is not provided in the document. Given the nature of a muscle stimulator, the "ground truth" would likely be objective physiological measurements (e.g., blood flow, muscle contraction), rather than subjective expert assessment requiring adjudication.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

An MRMC study is typically performed for diagnostic devices where human readers interpret medical images or data. For a powered muscle stimulator, an MRMC study comparing human reader improvement with and without AI assistance is not applicable and was not performed/reported.

6. Standalone (Algorithm Only Without Human-in-the-Loop Performance) Study

The StimSox™ System is a hardware device with embedded firmware for input controls and output display. It is not an AI algorithm that provides diagnostic or predictive outputs in a standalone manner. Therefore, a standalone performance study in the context of "algorithm only" is not applicable and was not performed/reported as it would be for an AI/ML-based diagnostic device. The device's "performance" is its ability to deliver electrical stimulation as intended for its physiological effect.

7. Type of Ground Truth Used

Based on the nature of the device and the brief mention of the validation study:

The "desired clinical response" for the StimSox validation study (a "small contraction of the plantar muscles of the foot") suggests physiological measurements or direct observation of muscle response would constitute the ground truth.
The indication ("temporarily increase local blood circulation") would imply ground truth established by physiological measurements of blood flow (e.g., Doppler ultrasound, plethysmography).

8. Sample Size for the Training Set

The StimSox™ System uses "embedded firmware written for a microcontroller" with a "real-time loop that is event driven." This indicates traditional microcontroller programming, not a machine learning model that requires a distinct "training set." Therefore, the concept of a "training set" sample size is not applicable to this device in the same way it would be for an AI/ML system.

9. How the Ground Truth for the Training Set Was Established

As there is no indication of a machine learning model or a "training set" in the context of AI, this question is not applicable. The device's functionality is based on programmed logic rather than learned patterns from data.

Summary

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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 (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 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 ( Select one or both, as applicable )
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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: 888-784-6633 Fax: 716-631-1273

Contact Person:	Robert E. Kaplan, MD
	President, StimMed LLC
	388 Evans Street
	Williamsville, NY 14221
	Fax: 716-883-3203
	REKaplanMD@aol.com

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.
1. Protected from inadvertent changes of stimulation level using timed autolock.
1. 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	StimSoxTMK151922	AMD 6605K092990	Justification
Manufacturer	StimMed, LLC	Advantageous MedicalDevices, LLC	N/A
Indications for Use	The StimSoxTM System is indicatedto temporarilyincrease local bloodcirculation inhealthy leg muscles.	Indications for TENSfunction:• Symptomatic reliefand management ofchronic (long-term),intractable pain and anadjunctive treatment inthe management ofpost-surgical pain orpost-traumatic acutepain.Indications for NMESfunction:• Relaxation of musclespasms• Prevention orretardation of disuseatrophy• Increasing local bloodcirculation• Muscle re-education• Immediate post-surgical stimulation ofcalf muscles to preventvenous thrombosis	Although the predicate has moreclaims than the subject device, theIFU of the subject device is withinthe scope of the NMES function ofthe predicate device.
Comparison Feature	StimSox™K151922	AMD 6605K092990	Justification
		• Maintaining orincreasing range ofmotion
Electrodes	2	4 (Two electrodes perchannel)	The number of electrodes is aconsequence of the number ofchannels.
Electrode type	Gel ElectrodeOne 2 inch roundself-adheringdisposable and One4x2 inch oval self-adhering disposableComfort Gel A 032Model 807	Gel Electrode2 inch round self-adhering reusableAmGEL AG702 (NowAG735).	Comfort Gel A 032 Model 807 iscleared under K072799 andK101576
Waveform	Biphasic	Monophasic	There is a requirement forelectrical stimulators to have noD.C. component or arationalization why there is a D.C.component (60601-2-10). TheStimSox™ System does not have aD.C. component because it isbiphasic. The predicate is listed asmonophasic and thus must have aD.C. component.
Maximum Intensity	30 mA	70 mA	The predicate supports more thantwice the maximum current. Basedon the Clinical Data Review, thislimited output is sufficient to meetthe clinical needs for theStimSox™ System.
Current step size	1 mA steps	0.5 mA steps	The differences in currentincrements, are small and do notaffect the desired clinical response,which is a small contraction of theplantar muscles of the foot. TheStimSox validation studydemonstrated that the 1.0mAincrements were safe and effectivein achieving the desired clinicalresponse.
Power Source	3 batteries typeAAA Non-rechargeable	4 batteries type AAAalkaline or rechargeableNi MH	The line isolation of the AMDdevice is for units that also plug in.This difference is not significant asit does not affect the effectivenessor safety of the device as theStimSox™ System will not needthe plug in feature.
Method of Line CurrentIsolation	Not Applicable	Unknown	The StimSox™ System is batterypowered.
Patient Leakage Current:	Not Applicable	Not Applicable	There is no patient leakage becausethe StimSox stimulator is battery
Normal Condition			powered.
Comparison Feature	StimSox™K151922	AMD 6605K092990	Justification
-Single Fault Condition	Not Applicable	Not Applicable
Number of Output Modes	One	Three	The predicate device is indicatedfor more uses than the StimSox™ System.
Number of Output Channels	One	Two	The number of channels is less onthe StimSox™ System because ithas reduced functionality whencompared to the predicate.
-Synchronous orAlternating	Not Applicable	Unknown
-Method of ChannelIsolation	Not Applicable	Unknown
Regulated Current orRegulated Voltage	Current	Current	Same
Software/Firmware/Microprocessor Control	Yes	Yes	Same
Automatic Overload Trip	Yes	Unknown	This difference has no effect on thesafety and effectiveness of thedevice.
Automatic No-Load Trip	Yes	Unknown	This difference has no effect on thesafety and effectiveness of thedevice.
Automatic Shut Off	Yes	Yes	Same
Patient Override Control	No	Unknown	The patient can remove theStimSox stimulator or turn itdown.
Indicator Display:			The StimSox User Manualinstructs the user to change thebatteries. Not including a low
-On/Off Status	Yes	Yes	battery indicator will not affect the
-Low Battery	No	Yes	Safety or Effectiveness of thestimulator.
-Voltage/Current Level	Yes	Yes
Timer Range (minutes)	N/A	0 to 90	The StimSox device is continuous
Compliance withStandards	ISO 10993-1ISO10993-10ISO 10993-12IEC 60601-1-6/A1:2013IEC 62366/A1:2014IEC 60602-1-11:2010IEC 60601-2-10:2012IEC 60601-1-2:2007(Ed. 3.0)IEC 60602-2-10:2012	ISO 10993-1ISO 10993-12ISO 10993-10IEC 60601-1:1988+A1:1991+A2:1995IEC 60601+1-2:2001/A:1:2004IEC 60601-14:2000IEC 60601-1-6;2004	The standards applied to theStimSox™ System are the morerecent versions of the predicate.
Comparison Feature	StimSox™K151922	AMD 6605K092990	Justification
Compliance with 21CFR 898	N/A	Unknown	The design of the StimSox™System does not include leadwires.
Weight	102.55g withbatteries	115g with batteries	This difference has no effect on theSafety or Effectiveness of thedevice.
Dimensions (inches)[W x H x D]	3.62x2.87x1.10	5.55x2.48x0.70	This difference has no effect on theSafety or Effectiveness of thedevice.
Housing Materials andConstruction	Plastic Enclosure	Plastic Enclosure	Same
Keyboard lock	Automatic	Automatic	Same
Programs	1 preset	10 preset and 10 useradjustable	The predicate device includes moreindications for use.
Time of treatment	4-18 hours	Treatment time withauto shut off	The StimSox design is a simplerdevice with a specific indication ofonly the foot muscles. Thepredicate is a general use devicethat can be used on variousvoluntary 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.

Regulation Number and Section

§ 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).