The Digitimer DS7AP Constant Current Stimulator is indicated for use as an adjunct in the treatment of high and low anorectal malformations by helping in the identification of the striated muscles to be used in anal reconstructions.

Device Description

The DS7AP Constant Current Stimulator has been specially designed to meet the requirements of pediatric surgeons who need a reliable and easy to use muscle locating stimulator when carrying out the Peña, "Pull-through" or posterior sagittal anorectoplasty (PSARP) anorectal reconstruction technique.

AI/ML Overview

Here's a breakdown of the acceptance criteria and supporting study information:

1. Table of Acceptance Criteria and Reported Device Performance:

Acceptance Criteria (Measured Characteristics of the Device Compared to Predicate)	Reported Device Performance (DS7AP)	Predicate Device Performance (PS-1)
Intended Use	Used to identify striated muscle in the treatment of high and low anorectal malformations	Used to identify striated muscle in the treatment of high and low anorectal malformations
Indications for Use	Adjunct in the treatment of high and low anorectal malformations by helping in identification of the striated muscle to be used in anal reconstructions	Adjunct in the treatment of high and low anorectal malformations by helping in identification of the striated muscle to be used in anal reconstructions
Classification	Class II	Class II
Product Code	IPF	IPF
Regulation Number	CFR 890.5850	CFR 890.5850
Power Source	Supply Mains (115/230V; 50/60Hz)	Primary battery (PP3 / 1604)
Number of Output Channels	One	One
Output Control	Constant Current	Constant Current
Firmware Control?	No	No
Automatic Overload Trip?	Yes	No
Compliance with 21 CFR 898?	Yes	No
Weight	4.85lb	1.52lb
Dimensions (wxhxd)	8.6"x4.4"x 9.9"	3.75"x3.5"x6.25"
Housing Materials	Thermo-plastic with metal front and rear panels	Thermo-plastic with metal front and rear panels
Waveform	Pulsed mono-phasic	Pulsed mono-phasic
Waveform Shape	Rectangular	Rectangular
Maximum Output Voltage (at 500Ω)	56V	122V
Maximum Output Voltage (at 2kΩ)	126V	220V
Maximum Output Current (at 500Ω)	112mA	244mA
Maximum Output Current (at 2kΩ)	63mA	110mA
Maximum Output Current (at 10kΩ)	13mA	22mA
Pulse Width	200µs / 500µs	175µs
Pulse Frequency	50Hz	65Hz
Maximum Phase Charge (at 500Ω)	56µC	42.2µC
Maximum Current Density (at 500Ω)	0.127mA/cm²	0.117mA/cm²
Maximum Power Density (at 500Ω)	0.191W/cm²	0.161W/cm²
Electrical Performance (DS7AP Specific)	Power: 100-120V or 200-240V, 47-63Hz, 12VA. Class 1 with Type BF applied part. Pulse duration: LO (200µs) or HI (500µs). Current: 0-100mA. Compliance voltage: 100V. Output frequency: 50Hz.	N/A (predicate has different power source)

Notes on Acceptance and Performance:

The primary acceptance criteria for the DS7AP were related to demonstrating substantial equivalence to the predicate device (Radionics Pena Muscle Stimulator PS-1 - K980448) in terms of intended use, indications for use, and technological characteristics.

While there are differences in specific electrical output values (e.g., maximum output voltage and current, pulse width, pulse frequency), power source, and some safety features (automatic overload trip, compliance with 21 CFR 898), the manufacturer argued and the FDA determined that these differences do not raise different questions of safety or effectiveness. For instance, regarding the power source difference, the subject device's power supply is "identical to that of the Digitimer DS7A/AH Constant Current Stimulators, which are approved for marketing under number K051357."

2. Sample size used for the test set and the data provenance:

Sample Size: Not applicable. The submission states that no clinical tests were required for this submission. The evaluation was based on non-clinical testing and comparison of technological characteristics to a predicate device.
Data Provenance: Not applicable for a test set as no clinical tests were performed.

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts:

Not applicable as no clinical tests were conducted and thus no expert-established ground truth for a test set was established.

4. Adjudication method for the test set:

Not applicable as no clinical tests were conducted.

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. This device is a constant current stimulator, not an AI-assisted diagnostic tool for human readers. No MRMC study was performed.

6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:

Not applicable. This is a medical device (constant current stimulator), not an algorithm. Its function is to directly stimulate muscles, not to provide an output that requires standalone evaluation against a ground truth in the way an algorithm would.

7. The type of ground truth used (expert consensus, pathology, outcomes data, etc):

Not applicable. The substantial equivalence determination was based on non-clinical testing to national and international standards (e.g., EN 60601-1, IEC 60601-1-2, IEC 62366-1, ISO 14971, EN 60601-2-10) and a comparison of technological characteristics to a legally marketed predicate device.

8. The sample size for the training set:

Not applicable as this is a medical device, not an AI/machine learning model that requires a training set.

9. How the ground truth for the training set was established:

Not applicable as no training set was used.

Summary

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March 6, 2018

Digitimer Ltd. John Smale Managing Director 37 Hydeway Welwyn Garden City, Hertfordshire, AL7 3BE, UK

Re: K172381

Trade/Device Name: Digitimer DS7AP Constant Current Stimulator Regulation Number: 21 CFR 890.5850 Regulation Name: Powered Muscle Stimulator Regulatory Class: Class II Product Code: IPF Dated: January 3, 2018 Received: January 8, 2018

Dear John Smale:

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 with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Part

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801); medical device reporting of medical device-related 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.

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.

For comprehensive regulatory information about mediation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/MedicalDevices/DeviceRegulationandGuidance/) and CDRH Learn (http://www.fda.gov/Training/CDRHLearn). Additionally, you may contact the Division of Industry and Consumer Education (DICE) to ask a question about a specific regulatory topic. See the DICE website (http://www.fda.gov/DICE) for more information or contact DICE by email (DICE@fda.hhs.gov) or phone (1-800-638-2041 or 301-796-7100).

Sincerely.

Vivek J. Pinto -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) K172381

Device Name

Digitimer DS7AP Constant Current Stimulator

Indications for Use (Describe)

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)

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510(k) Summary

Submitter:	Digitimer Ltd
Submitter's Address:	37 Hydeway,Welwyn Garden City,Hertfordshire,AL7 3BE, UK
Contact person:	John SmaleManaging Director+44 (0)1707 328347
Date Summary Prepared:	December 31, 2017
510(k) Number:	K172381
Device Name:	DS7AP Constant Current Stimulator
Device Common Name	Powered Muscle Stimulator; CFR890.5850
Device Classification:	Class II
Predicate Device:	Radionics Pena Muscle Stimulator PS-1 - 510(k) K980448
Indications for Use:	The Digitimer DS7AP Constant Current Stimulator is indicated as anadjunct in the treatment of high and low anorectal malformations byhelping the identification of striated muscle to be used in analreconstructions.
Device Description:	The DS7AP Constant Current Stimulator has been specially designedto meet the requirements of pediatric surgeons who need a reliableand easy to use muscle locating stimulator when carrying out thePeña, "Pull-through" or posterior sagittal anorectoplasty (PSARP)anorectal reconstruction technique.
Intended Patient Population	The reconstruction surgeries, for which the DS7AP is intended, aretypically carried out in young children (<3 years).
Intended Part of the Body to be Interacted With	The DS7AP is used in the treatment of anorectal malformations byhelping the identification of striated muscles to be used in analreconstructions.
Intended User Profile	The intended User is a specialist clinician trained inNeurophysiological studies, or a surgeon trained in the specialistreconstruction surgeries for which the DS7AP is intended. They arelikely to be either a doctor with neurology training or a ClinicalNeurophysiological Scientist for which the training requirementrecommendations (in the UK) is 4 years of undergraduate study.

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	Intended Conditions of Use
	The DS7AP is intended for static table top use in a clinical
	environment, typically a neurosurgery operating theatre.
Electrical Performance:	Power: 100-120V or 200-240V (externally selected), 47-63Hz, 12VA.Classification: IEC 60601-1 Class 1 with Type BF applied part.Power: Push rod On/Off switch.Pulse duration: LO (200µs) or HI (500µs), two position rotary switch.Current: 0-100mA, continuously adjustable dial.Compliance voltage: 100V.Output frequency: 50Hz.Output enable: Toggle Switch (On is Up, Off/Reset is down).Output connections: 4mm shrouded, touch-proof sockets (red andblack) on 3/4" centers.Footswitch connection rear panel 3.5mm mono jack socket (foroptional D185-FS1 contact closure footswitch).
Mechanical Performance:	Size: 10" x 4" x 10" (255 x 100 x 225 mm) - d x h x w10.6" x 4.33" x 9" (270 x 110 x 225 mm) - d x h x w - over controlsand feet.Weight: 4.5 pounds (2.1 kg) approx.
Temperature:	Operating Range 50°F to 104°F (10°C to 40°C) 30 to 75%, non-condensingStorage Range -40°F to 158°F (-40°C to 70°C) 10 to 100%, non-condensingTransport Range -40°F to 158°F (-40°C to 70°C) 10 to 100%, non-condensing
Other:	Power: 115V or 230V @ 50/60 HzRating: <30 VACase Material: UL94 V-0 Flame Retardant
Front Panel Indicators:	Power: Green LED, illuminated for power ON.Trigger: Amber LED, illuminated to indicate stimulus trigger is active.Compliance: Amber LED, illuminated if the compliance limit isreached i.e. the current requested cannot be delivered (e.g. due tohigh resistance between probe tips).Reset/Fault: Amber LED illuminated and latched for sensed overcurrent and at power on.
Installation	The DS7AP does not need installation by Digitimer personnel as theyare supplied with comprehensive instructions and are easy to set up& operate.

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Footswitch: The footswitch is a medical grade foot switch that is sealed to IP68 so as to meet all the requirements of IEC 60601-1 for use within operating theatres.

Disposable Precision Bipolar Stimulation Probe:

Available in packs of 10 probes, the Technomed Neurosign Precision Bipolar Probe is an ideal single-use stimulation probe. The probes are fitted with 1.5mm DIN 42 802 connectors and need to be used in conjunction with our 2m long D185-HB4-2m Output Extension Cable The Precision Bipolar Probe has been cleared for marketing by the FDA under number K050325. This included an evaluation of biocompatibility

Technological Characteristics:

Characteristic:	Subject Device: DS7AP	Predicate Device: PS-1
510(k) number	K172381	K980448
Intended Use	Used to identify striated muscle inthe treatment of high and lowanorectal malformations	Used to identify striated muscle inthe treatment of high and lowanorectal malformations
Indications for Use	The DS7AP is indicated for use ofas an adjunct in the treatment ofhigh and low anorectalmalformations by helping inhelping in identification of thestriated muscle to be used in analreconstructions	The PS-1 is indicated for use of asan adjunct in the treatment ofhigh and low anorectalmalformations by helping inhelping in identification of thestriated muscle to be used in analreconstructions
Classification	Class II	Class II
Product Code	IPF	IPF
Regulation Number	CFR 890.5850	CFR 890.5850
Power Source	Supply Mains (115/230V; 50/60Hz)	Primary battery (PP3 / 1604)
Number of OutputChannels	One	One
Output Control	Constant Current	Constant Current
Firmware Control?	No	No
Automatic OverloadTrip?	Yes	No
Compliance with 21CFR 898?	Yes	No
Weight	4.85lb	1.52lb
Dimensions (wxhxd)	8.6"x4.4"x 9.9"	3.75"x3.5"x6.25"
Housing Materials	Thermo-plastic with metal frontand rear panels	Thermo-plastic with metal frontand rear panels
Waveform	Pulsed mono-phasic	Pulsed mono-phasic
Waveform Shape	Rectangular	Rectangular
Maximum OutputVoltage1	56V @ 500Ω126V @ 2kΩ	122V @ 500Ω220V @ 2kΩ

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Characteristic:	Subject Device: DS7AP	Predicate Device: PS-1
Maximum OutputCurrent²	112mA @ 500Ω63mA @ 2kΩ13mA @ 10k Ω	244mA @ 500Ω110mA @ 2kΩ22mA @ 10k Ω
Pulse Width	200µs / 500µs	175µs
Pulse Frequency	50Hz	65Hz
Maximum PhaseCharge	56µC @ 500Ω	42.2µC @ 500Ω
Maximum CurrentDensity³	0.127mA/cm² @ 500Ω	0.117mA/cm² @ 500Ω
Maximum PowerDensity³	0.191W/cm² @ 500Ω	0.161W/cm² @ 500Ω
Notes:
1. Peak voltage, dependent upon the current control setting and the fixed load resistance.

Peak current, limited by the maximum compliance voltage available.
Figures assume use of the G3604-00 Disposable Probe for both devices.

Different Technological Characteristics:

The subject device and the predicate differ in the power source used, with the subject using mains power and the predicate using batteries.

The power supply of the subject device is identical to that of the Digitimer DS7A/AH Constant Current Stimulators, which are approved for marketing under number K051357.

Nonclinical Tests:

Nonclinical tests have been based on the compliance with the following international standards.

Standard Utilized	FDA Consensus Standard	Comments
EN 60601-1:2006	AAMI ANSI ES60601-1:2005/(R) 2012 andA1:2012	Differencescovered byadditionaltesting
EN 60601-1-2:2007	IEC 60601-1-2:2007	Same
IEC 62366-1:2015	AAMI ANSI IEC 62366-1:2015	Same
ISO 14971:2007	ISO 14971:2007	-
EN 60601-2-10:2015+ A1:2016	IEC 60601-2-10:2012	-
FDA GuidanceDocument forPowered MuscleStimulator 510(k)	None	Comparisonof DS7AP andpredicatedevice

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Clinical Tests:

No clinical tests are required for this submission

Conclusions of Nonclinical & Clinical Tests:

The DS7AP Constant Current Stimulator meets the requirements of the non-clinical testing defined above.

The intended use and the technological characteristics have also been compared in detail with the predicate device and found to be substantially equivalent.

No clinical tests were required to support this 510(k)

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).