When the Low output is selected the MS-120BK is used as a nerve stimulator for surgical procedures and brain mapping during treatment of patients with seizure disorders.

When High output is selected the MS-120BK is used for the intraoperative diagnosis of acute dysfunction in corticospinal axonal conduction brought about by mechanical trauma (traction, shearing, laceration, or compression) or vascular insufficiency.

The system is intended for use by qualified medical personnel within a hospital or clinical environment. The stimulator is available for use on any patients as determined by the qualified medical personnel.

Device Description

The Nihon Kohden MS-120BK is a dual (high & low) output constant current stimulator. The high and low setting, stimulation current and frequency of stimulation is selected by the user. The Nihon Kohden MS-120BK is connected to the MEE 1000A through the JB-116BK or JB-132BK amplifier.

In the Low output setting the Nihon Kohden MS-120BK applies cortical stimulation energy through the Nihon Kohden stimulation pod (JS-102B) which is connected to commercially available cortical electrodes (strip and grid electrodes).

In the High output setting, the MS-120BK outputs electrostimulation pulse through the Nihon Kohden extension cord (BM-121B) which is connected to commercially available stimulation electrode(s).

AI/ML Overview

This document describes a 510(k) submission for the Nihon Kohden MS-120BK Electric Stimulator (Extension Unit), primarily focusing on demonstrating its substantial equivalence to previously cleared predicate devices. Therefore, the study doesn't present typical "acceptance criteria" and "reported device performance" in the way one might expect for a novel AI/software device. Instead, the focus is on showing technical characteristics are equivalent and that the device complies with recognized safety standards.

Here's an analysis based on the provided text, addressing your points where information is available:

1. Table of Acceptance Criteria and Reported Device Performance

The submission demonstrates equivalence by comparing the technical characteristics of the new device to predicate devices. The "acceptance criteria" here are effectively that the new device's specifications fall within acceptable ranges similar to or better than the predicate devices, and that it complies with relevant safety and performance standards. The "reported device performance" is a direct comparison of these specifications.

Characteristic	Predicate Device (Nihon Kohden SEN-4100A)	Predicate Device (Digitimer D185)	New Device (Nihon Kohden MS-120BK)	Acceptance Criteria (Implied)	Reported Device Performance
High Output Setting
Voltage	1000V	1000V	350V	Similar or acceptable range	350V
Current	1A (1k Ω load)	1A (1k Ω load)	200mA (1k Ω load)	Similar or acceptable range	200mA (1k Ω load)
Maximum Stimulation Energy	50mJ	50mJ	40mJ	Similar or acceptable range	40mJ
Output Impedance	less than 120 Ω	less than 120 Ω	50 Ω	Similar or acceptable range	50 Ω
Stimulation Mode	Constant Voltage	Constant Voltage	Constant Current	Demonstrates different, but acceptable and defined mode	Constant Current
Pulse Duration	50 μs	50 μs	50-1000 μs	Similar or acceptable range	50-1000 μs
Output Frequency Range	1 Hz	1 Hz	0.1-1Hz	Similar or acceptable range	0.1-1Hz
Number of Pulse Trains	1-9	1-9	1-9	Matches	1-9
Interpulse Interval	1.0-9.9ms	1.0-9.9ms	1.0-1000ms	Similar or acceptable range	1.0-1000ms
Limitation of Voltage/Current and Pulses	Varies with predicates	Varies with predicates	Varies (e.g., 200mA: 3 Pulses)	Similar or acceptable range	Varies
Polarity Change	OK	OK	OK	Matches	OK
Monophasic	OK	OK	OK	Matches	OK
Biphasic	NO	NO	OK	Demonstrates additional capability	OK
Alternate	NO	NO	OK	Demonstrates additional capability	OK
Maximum Charge	50 micro-Coulomb	50 micro-Coulomb	200 micro-Coulomb	Similar or acceptable range	200 micro-Coulomb
Pulse Shape	Rectangular	Rectangular	Rectangular	Matches	Rectangular
Maximum Energy Per Pulse	50mJ	50mJ	40mJ	Similar or acceptable range	40mJ
Maximum Energy Per Second	150mJ	150mJ	40mJ	Similar or acceptable range	40mJ
Electrode Minimum Size	0.5cm2	0.5cm2	0.5cm2	Matches	0.5cm2
Maximum Charge Density	100 Micro-C/cm2	100 Micro-C/cm2	400 Micro-C/cm2	Similar or acceptable range	400 Micro-C/cm2
Interface Control	MEE-1000A	NO	Only MEE-1000A	Specifies compatibility	Only MEE-1000A
Trigger Input	OK	OK	*OK2**	Matches	OK*2
Trigger Output	OK	OK	*OK2**	Matches	OK*2
Foot Switch Control	OK	OK	*OK2**	Matches	OK*2
Low Output Setting
Constant Current Stimulator	Yes (Nicolet)	Yes (Ojemann)	Yes	Matches	Yes
Maximum Stimulation Charge	15 micro-Coulomb (Nicolet)	20 micro-Coulomb (Ojemann)	4.5 micro-Coulomb	Similar or acceptable range	4.5 micro-Coulomb
Current Stimulation Range	0.1 to 15mA (peak) (Nicolet)	0 to 10mA (peak) (Ojemann)	0 to 15mA (peak)	Similar or acceptable range	0 to 15mA (peak)
Stimulation Frequency	1 to 100Hz (Nicolet)	5, 10, 20, 50, 75, 100Hz (Ojemann)	0.1 to 50Hz	Similar or acceptable range	0.1 to 50Hz
Stimulation Pulse Width Duration	0.1 to 1.0 msec Per Phase (Nicolet)	0.1 to 2.0 msec Per Phase (Ojemann)	0.05 to 0.3 msec Per Phase	Similar or acceptable range	0.05 to 0.3 msec Per Phase
Pulse Shape	Rectangular (Nicolet)	Rectangular (Ojemann)	Rectangular	Matches	Rectangular
Electrode Minimum Size	0.04cm2 (Nicolet)	0.5cm2 (Ojemann)	0.04cm2	Similar or acceptable range	0.04cm2
Maximum Charge Density	375 micro-C/cm2 (Nicolet)	40 micro-C/cm2 (Ojemann)	113 micro-C/cm2	Similar or acceptable range	113 micro-C/cm2
Maximum RMS Current Density Per Pulse	119 mA RMS/cm2 (Nicolet)	8.9 mA RMS/cm2 (Ojemann)	46 mA RMS/cm2	Similar or acceptable range	46 mA RMS/cm2

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

This is a physical medical device (electrical stimulator), not an AI/software device that processes data. Therefore, the concept of a "test set" with "data provenance" (country of origin, retrospective/prospective) in the context of image analysis or diagnostic algorithms does not apply here.

The "testing" mentioned is focused on verifying the device's hardware and software performance against its specifications and compliance with safety standards. The document states:

"Testing of the Nihon Kohden System with the MS-120BK was performed in compliance with the Nihon Kohden Corporation design control process."
"Testing included: Software and hardware verification and validation, and the device is in compliance with the following voluntary industrial standards..." (followed by a list of IEC, EN, and CAN/CSA standards).

This implies standard engineering and regulatory compliance testing rather than a clinical trial with patient data.

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

Not applicable. As noted above, this device does not function by interpreting patient data for diagnosis, so there is no "ground truth" established by experts in this context. The "truth" is whether the device meets its technical specifications and safety standards.

4. Adjudication Method for the Test Set

Not applicable for the same reasons as point 3.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, and the Effect Size

No. This type of study is typically performed for diagnostic or AI-assisted devices to assess the impact on human reader performance. The MS-120BK is an electrical stimulator, and its effectiveness is determined by its physical output and adherence to specifications, not by how it affects human interpretation of data.

6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done

No. This is a physical stimulus device, not an algorithm. Its operation is inherently with a "human-in-the-loop" (qualified medical personnel).

7. The Type of Ground Truth Used

The "ground truth" for this type of device is its technical specifications and compliance with international safety and performance standards. Testing involved verifying that the device's electrical outputs, timing, and other physical parameters matched the design specifications and met the requirements of standards like IEC 60601-1, IEC 60601-1-2, IEC 60601-2-40, etc.

8. The Sample Size for the Training Set

Not applicable. This device does not use machine learning algorithms that require a "training set."

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

Not applicable for the same reasons as point 8.

In summary, the provided document is a 510(k) summary for a traditional medical device (an electric stimulator). The "study" referenced is the internal design control process and associated testing to ensure the device meets its technical specifications safely and effectively, and is substantially equivalent to predicate devices, rather than a clinical study evaluating an AI/software's diagnostic or interpretive performance.

Summary

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Nihon Kohden America, Inc. July 25, 2011

Traditional 510(k) Notification MS-120 Electric Stimulator

K110410

510(k) Summary

ﺒﻪ .

Company Name:	Nihon Kohden Corporation90 Icon StreetFoothill Ranch, CA 92610	AUG - 4 2011
Device Name:	Nihon Kohden MS-120BK Electric Stimulator (Extension Unit)
510(k) Sponsor,Contact:	Nihon Kohden America, Inc.90 Icon StreetFoothill Ranch, CA 92610
	Steve GeerdesDirector Quality Assurance and Regulatory AffairsPhone: (949) 580-1555 Ext. 3325Fax: (949) 580-1550
Summary Date:	7/25/2011
Common Name:	MS-120BK Electric Stimulator (Extension Unit)

Classification Names:

Evoked Response Electrical Stimulator	882.1870	GWF
Cortical Electrode	882.1310	GYCClass II

Predicate Device(s):

Nicolet Cortical Stimulator	K072964
Ojemann Cortical Stimulator	K924226
Digitimer D185 Multipulse Cortical Stimulator	K020400
Axon Eclipse Neurological workstation	K050798
Nihon Kohden SEN-4100 Electric Stimulator	K071969

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, l

. 1.0 Description of Device

In the High output setting, the MS-120BK outputs electrostimulation pulse through the Nihon Kohden extension cord (BM-121B) which is connected to commercially available stimulation electrode(s).

2.0 Intended Use of Device

When the Low output is selected the MS-120BK is used as a nerve stimulator for surgical procedures and brain mapping during treatment of patients with seizure disorders.

3.0 Technical Characteristics

The technical characteristics of the MS-120BK are equivalent to those of the predicate devices. The following tables summarizes equivalence.

Stimulator Comparison	Predicate DeviceNihon KohdenSEN-4100A (K#071969)	Digitimer D185	New DeviceNihon KohdenMS-120BK
Stimulator Output
Voltage	1000V	1000V	350V
Current	1A (1k Ω load)	1A (1k Ω load)	200mA (1k Ω load)
Maximum Stimulation
Energy	50mJ	50mJ	40mJ
Output Impedance	less than 120 Ω	less than 120 Ω	50 Ω
Stimulation Mode	Constant Voltage	Constant Voltage	Constant Current
Stimulation Parameters

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స

Pulse Duration	50 μs	50 μs	50-1000 μs
Output Frequency Range	1 Hz	1 Hz	0.1-1Hz
Number of Pulse Trains	1-9	1-9	1-9
Interpulse Interval	1.0-9.9ms	1.0-9.9ms	1.0-1000ms
Limitation of Voltage /Current and Pulses	1000V: 3 Pulses510V: 6 Pulses350V: 9 Pulses	1000V: 3 Pulses510V: 6 Pulses350V: 9 Pulses	200mA: 3 Pulses1142mA: 6 Pulses1115mA: 9 Pulses*1
Polarity Change	OK	OK	OK
Monophasic	OK	OK	OK
Biphasic	NO	NO	OK
Alternate	NO	NO	OK
Maximum Charge	50 micro-Coulomb	50 micro-Coulomb	200 micro-Coulomb
Pulse Shape	Rectangular	Rectangular	Rectangular
Maximum Energy Per Pulse	50mJ	50mJ	40mJ
Maximum Energy PerSecond	150mJ	150mJ	40mJ
Electrode Minimum Size	0.5cm2	0.5cm2	0.5cm2
Maximum Charge Density	100 Micro-C/cm2	100 Micro-C/cm2	400 Micro-C/cm2
InterfaceControl From EP/EMGMachine	MEE-1000A	NO	Only MEE-1000A
Trigger Input	OK	OK	OK*2
Trigger Output	OK	OK	OK*2
Foot Switch Control	OK	OK	OK*2

*1: The pulse width in the case

. *2: Depends on interface of MEE-1000A

Stimulator Comparison	Predicate Device NicoletCortical Stimulator(K#072964)	OjemannCortical Stimulator(K#924226)	New DeviceNihon KohdenMS-120BK
Constant Current Stimulator	Yes	Yes	Yes
Maximum Stimulation Charge	15 micro-Coulomb	20 micro-Coulomb	4.5 micro-Coulomb
Current Stimulation Range	0.1 to 15mA (peak)	0 to 10mA (peak)	0 to 15mA (peak)
Stimulation Frequency	1 to 100Hz	5, 10, 20, 50, 75,100Hz	0.1 to 50Hz
Stimulation Pulse Width Duration	0.1 to 1.0 msec PerPhase	0.1 to 2.0 msec PerPhase	0.05 to 0.3 msec PerPhase
Pulse Shape	Rectangular	Rectangular	Rectangular
Electrode Minimum Size	0.04cm2	0.5cm2	0.04cm2
Maximum Charge Density	375 micro-C/cm2	40 micro-C/cm2	113 micro-C/cm2
Maximum RMS Current DensityPer Pulse	119 mA RMS/cm2	8.9 mA RMS/cm2	46 mA RMS/cm2

of 1ms

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4.0 Data Summary

Testing of the Nihon Kohden System with the MS-120BK was performed in compliance with the Nihon Kohden Corporation design control process. Testing included:

Software and hardware verification and validation, and the device is in compliance with the following voluntary industrial standards:

Medical Electrical Equipment Par1: General requirements for safety IEC 60601-J 1988 IEC 60601-1, Amendment 1 Part 1: General Requirements for safety, Amendment 1, 1991 IEC 60601-1, Amendment 2 Part 1: General Requirements for safety, Amendment 2, 1995 IEC 60601-1-2-40 * Part 2-40: Particular Requirements for the safety of electromyographs and evoked response equipment, 1998 IEC 60601-1-1 200 edition: Part 1-1: General requirements for safety -Collateral standard Safety requirements for medical electrical systems, 2000 IEC 60601-1-2 2" edition: Medical electrical equipment- Part 1: General requirements for safety - 2. Collateral standard: Electromagnetic compatibility, 2001 EN 60601-1: 1990 Equivalent to IEC 60601-1: 1998* EN 60601-1 Amendment 1 Medical equipment general requirements for safety, 1993 EN 60601-1 Amendment 2 Medical equipment general requirements for safety, 1995 EN 60601-1-1: 2001 Equivalent to IEC 60601-1:2001 Electromagnetic compatibility requirement test EN 60601-1-2:2001 CAN/CSA-C22.2 No. 601.1-M90 Medical electrical equipment, Part 1: General requirements for safety. CAN/CSA-C22.2 No. 601.1S1-94 Supplement No. 1-94 to CAN/CSA-C22.2 No. 601-1-M90 Medical Equipment- Part 1:General requirements for safety. CAN/CSA-C22.2 No. 60601-1-1-02 Medical electrical equipment, Part 1-1: General requirements for safety- Collateral: Safety requirements for medical electrical systems, 2006 CAN/CSA-C22.2 No. 60601-2-40-01 Medical electrical equipment, Part 2-40: Particular requirements for safety of electromyographs and evoked response equipment (adopted 60601-2-40: 1998 CAN/CSA-C22.2 No. 601.1B-90 Amendment 2 to CAN/CSA-C22.2 No. 601.1-M90 Medical equipment Part 1: General requirements for safety: 2002

5.0 Conclusions

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Substantial equivalence of the Nihon Kohden MS-120BK was demonstrated by testing in compliance with the Design Control process. The intended use and technology of the Nihon Kohden MS-120BK is equivalent to the predicate devices. No new questions of safety or effectiveness are raised.

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Image /page/5/Picture/1 description: The image shows a logo for the U.S. Department of Health & Human Services. The logo features a stylized caduceus symbol, which is a staff with two snakes coiled around it. The words "DEPARTMENT OF HEALTH & H." are arranged in a semi-circle around the caduceus. The image is in black and white.

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

Mr. Steve Geerdes Director Regulatory Affairs and Quality Assurance Nihon Kohden America, Inc. 90 Icon St. Foothill Ranch. CA 92610

AUG - 4 2011

Re: K110410

Trade/Device Name: Nihon Kohden MS-120BK Electric Stimulator (Extension Unit) Regulation Number: 21 CFR 882.1310 Regulation Name: Cortical Electrode Regulatory Class: Class II Product Code: GYC and GWF Dated: June 27, 2011 Received: June 28, 2011

Dear Mr. Geerdes:

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 801); medical device reporting (reporting of medical device-related adverse events) (21 CFR 803); good manufacturing practice requirements as set

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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 go to http://www.fda.gov/AboutFDA/CentersOffices/CDRH/CDRHOffices/ucm11.5809.htm for the Center for Devices and Radiological Health's (CDRH's) Office of Compliance. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21CFR 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 Small Manufacturers, International and Consumer Assistance 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,
Keoia Alexander

Malvina B. Eydelman, M.D. Director Division of Ophthalmic, Neurological, and Ear. Nose and Throat Devices Office of Device Evaluation Center for Devices and Radiological Health

Enclosure

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Indications for Use Form

510(k) Number (if known):

Device Name: _ _ MS-120BK Electric Stimulator (Extension Unit)

Indications for Use:

When the Low output is selected the MS-120BK is used as a nerve stimulator for surgical procedures and brain mapping during treatment of patients with seizure disorders.

Prescription Use (Part 21 CFR 801 Subpart D)

AND/OR

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

(PLEASE DO NOT WRITE BELOW THIS LINE-CONTINUE ON ANOTHER PAGE IF NEEDED)

Concurrence of CDRH, Office of Device Evaluation (ODE)

Kristen Bowsher

(Division Sign-Off) Division of Ophthalmic, Neurological and Ear, Nose and Throat Devices

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510(k) Number_K 110410

Regulation Number and Section

§ 882.1310 Cortical electrode.

(a)
Identification. A cortical electrode is an electrode which is temporarily placed on the surface of the brain for stimulating the brain or recording the brain's electrical activity.(b)
Classification. Class II (performance standards).