The Systems are intended for use as: devices that, by the use of diagnostic images of the patient, acquired specifically to assist the surgeon with presurgical planning, provide orientation and reference information during intra-operative procedures.

The Systems are indicated for use in: Guidance and localization in open craniotomies, and for surgeries that are traditionally performed with a stereotactic apparatus, such as biopsies, thalamotomies, and electrode implants. The Systems may also be used to review medical images in a neurosurgical context.

Device Description

The MAYFIELD®/ ACCISS™ Operating Arm System with Windows NT® for Cranial Surgery and MAYFIELD® Optical ACCISS™ System with Windows NT® for Cranial Surgery and with the Wireless Probe/DRF are modifications to existing systems. The modifications involve converting the operating system software to Windows NT from DOS and adding a battery-powered Wireless Probe and battery-powered Wireless Dynamic Reference Frame for use with the Optical System. The systems use diagnostic images of the patient for presurgical planning and provide orientation and reference information during intra-operative procedures. The systems utilize either arm or optical tracking for 3-D digitizing, interface to a computer graphics workstation, display reformatted CT or MR images, and use algorithms for image-guided surgery planning.

AI/ML Overview

The provided text is a 510(k) Summary for a medical device (MAYFIELD®/ACCISS™ System), describing modifications to existing systems. It focuses on demonstrating substantial equivalence to predicate devices rather than proving the device meets specific acceptance criteria through a clinical study. Therefore, much of the requested information regarding acceptance criteria and studies (like sample size, data provenance, expert ground truth, MRMC studies, standalone performance, training set details) is not present in this document.

However, based on the provided text, I can extract information related to the device's performance demonstration for substantial equivalence.

Here's a breakdown of what can and cannot be answered from the provided text:

1. A table of acceptance criteria and the reported device performance

The document does not specify formal "acceptance criteria" in terms of quantitative performance metrics (e.g., accuracy thresholds, sensitivity/specificity targets) for the new modifications. Instead, the "performance" demonstrated is that the modifications (Windows NT software and Wireless Probe/DRF) did not change the functionality of the systems compared to the predicate devices.

Feature / Criteria (Implied)	Reported Device Performance (Modified System)
Intended Use	Same as predicate; unchanged.
Indications for Use	Same as predicate; unchanged.
Functions of Systems	Unchanged from predicate systems.

2. Sample size used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)

This information is not provided in the document. The text only states that "Tests simulating cranial surgery planning were performed." It does not specify the number of tests, the type of data (e.g., patient data, simulated models), or its provenance.

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts (e.g. radiologist with 10 years of experience)

This information is not provided. The text does not mention the use of experts to establish a "ground truth" for the testing in the context of clinical performance. The comparison was against the functional performance of the predicate devices.

4. Adjudication method (e.g. 2+1, 3+1, none) for the test set

This information is not provided.

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

This is not applicable and not performed. The device described is a computer-based image-guided surgical planning system, not an AI diagnostic tool primarily impacting human reader performance. The modifications were to the operating system and a wireless accessory.

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

A standalone performance evaluation in the typical sense of AI algorithms is not described. The "tests simulating cranial surgery planning" would inherently involve the system's functionality, but the document doesn't detail performance metrics like accuracy, precision, or error margins for the system itself. The focus was on comparing the modified system's operation to the predicate system's operation.

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

The concept of "ground truth" in the context of clinical outcomes or diagnostic accuracy is not applicable to the described study. The study involved a functional comparison; the "ground truth" for these tests was the expected behavior and output of the predicate devices.

8. The sample size for the training set

This is not applicable and not provided. This document pertains to modifications of an existing image-guided surgery system, not the development or training of an AI algorithm from a training set.

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

This is not applicable and not provided.

Summary of the Study (as described in the document):

The study performed was a comparative functional validation.

Study Design: The manufacturer performed "Tests simulating cranial surgery planning" using the modified systems (Arm System with Windows, Optical System with Windows and Wireless Probe/DRF).
Comparison: The results of these tests were "compared to the results of the same tests performed with the DOS-based Systems and with the wired Probe and DRF" (the predicate devices).
Objective: To demonstrate that the "functions of the Arm and Optical Systems were unchanged" despite the modifications.
Conclusion: Based on this comparison, the manufacturer concluded that the modifications "do not raise any new unresolved issues relating to safety and effectiveness" and that the modified systems are "substantially equivalent to the predicate Systems."

Essentially, the study aimed to show that changing the operating system and adding a wireless accessory did not alter the fundamental, proven functionalities of the existing medical devices.

Summary

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Image /page/0/Picture/2 description: The image shows a logo for Ohio Medical Instrument Company Inc. located in Cincinnati, Ohio 45227. The image also contains the text "II 510(k) SUMMARY" and the date "NOV - 2 1999". The logo features a medical symbol with a snake wrapped around a staff.

Summary of Safety and Effectiveness

MAYFIELD®/ ACCISS™ System with Windows NT® for Cranial Surgery and MAYFIELD® Optical ACCISS" System with Windows NT® for Cranial Surgery and with the Wireless Probe/Dvnamic Reference Frame

This Summary is submitted pursuant to Section 513(i) of the Federal Food, Drug and Cosmetics Act, as amended by the Safe Medical Devices Act [SMDA] of 1990, and in accordance with the requirements of 21 C.F.R. § 807.92.

1. This Summary was prepared on August 20, 1999. The Submitter's Name and Address & the name of the Contact Person are: Ohio Medical Instrument Company, Inc. 4900 Charlemar Drive Cincinnati, Ohio 45227 U.S.A. Fax: (513) 561-0195 Phone: (513) 561-2241 Kenneth B. Miller, Director, Regulatory Affairs and Quality Assurance
This Premarket Notification describes modifications to the MAYFIELD® ACCISS" System 2 [hereafter Arm System] and to the MAYFIELD®/ Optical ACCISS™ System [hereafter Optical System]. The common name of these Systems is Computer-Based Image-Guided Stereotactic Surgery Planning Systems, and the classification name is Stereotactic Instrumentation.
The predicate devices are the MAYFIELD® ACCISS" Image-Guided Stereotactic 3. Workstation (K955397) and the MAYFIELD®/ Optical ACCISS "Image-Guided Stereotactic Workstation [OASYS™] (K982244).
1. The modifications apply to cranial surgery and involve; a) conversion of the operating system software for both Systems to Windows NT (hereafter "Windows") from DOS, and b) addition of a battery-powered Wireless Probe and battery-powered Wireless Dynamic Reference Frame [hereafter Wireless Probe/DRF] for use with the Optical System.
ട്. "Windows" is operating system software that, in conjunction with the Arm and Optical Systems, allows the user to select and simultaneously display and/or keep on the screen a number of images of interest, "zoom" images to larger sizes and move images to different locations on the monitor screen. "Windows" replaces and is substantially equivalent to the DOS operating system software used by the predicate Systems. Changes to the overall design of the screens and to the way the Systems are used have been minimized to make the transition easy for the user.

Windows NT is a registered trademark of Microsoft Corp.

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II 510(k) SUMMARY (continued)

The Wireless Probe/DRF each carries a sterile battery for their power. When coupled with 6. the Optical System, the wireless models function in the same way as the wired versions by allowing preoperative and operative planning surgical procedures using CT or MR images.
K992843
The addition of "Windows" and the Wireless Probe/DRF has not changed the Intended Use of 7. the Arm System and the Optical System. The Arm and Optical Systems are intended for use as devices that use diagnostic images of the patient, acquired specifically to assist the surgeon with presurgical planning, to provide orientation and reference information during intra-operative procedures. There are no operational differences between "Windows" and DOS or between the Wireless Probe/DRF and the wired Probe/DRF. All phases of preoperative and operative planning for cranial surgery remain the same.
"Windows" is operating system software that replaces the predicate DOS operating system 8. software. It does not introduce any technological changes to the Systems other than the ability to display and/or keep a number of images simultaneously on the monitor screen, "zoom" the images to larger sizes and move the images to different locations on the monitor screen. With the exception of the power source, the technological characteristics of the Wireless Probe/DRF are the same as or similar to those of the predicate wired devices where LED-based systems and infrared signals are used to provide tracking information as an aid to surgery.
ഗ് Tests simulating cranial surgery planning were performed using the Arm System with "Windows" and the Optical System with "Windows" and with the Wireless Probe/DRF. The results were compared to the results of the same tests performed with the DOS-based Systems and with the wired Probe and DRF. This comparison demonstrated that the functions of the Arm and Optical Systems were unchanged.
1. Based upon the above points, OMI has concluded that for cranial surgery, the Arm System with "Windows" and the Optical System with "Windows" and with the Wireless Probe/DRF do not raise any new unresolved issues relating to safety and effectiveness. Ohio Medical Instrument Company, Inc. therefore considers the Arm System with "Windows" and the Optical System with "Windows" and with the Wireless Probe/DRF, to be substantially equivalent to the predicate Systems.

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II 510(k) SUMMARY (continued)

FEATURE	MAYFIELD®/ ACCISS™ Operating Armand Optical ACCISS™ Systems[K955397, K982244]	MAYFIELD®/ ACCISS™ System with"Windows" for Cranial Surgery andMAYFIELD® Optical ACCISS™ Systemwith "Windows" for Cranial Surgeryand with the Wireless Probe/DRF
Intended Use	The Systems are intended for use as:• devices that, by the use of diagnosticimages of the patient, acquiredspecifically to assist the surgeon withpresurgical planning, provideorientation and reference informationduring intra-operative procedures.	The Systems are intended for use as:• Same.
Indications forUse	The Systems are indicated for use in:• Guidance and localization in opencraniotomies, and for surgeries that aretraditionally performed with astereotactic apparatus, such asbiopsies, thalamotomies, and electrodeimplants. The Systems may also beused to review medical images in aneurological context.	The Systems are indicated for use in:• Same.
Design	• Arm or Optical tracking for 3-Ddigitizing.• Interfaces to computer graphicsworkstation.• Displays reformatted CT or MR imagesin variety of configurations.• Algorithms for image-guided surgeryplanning.• Software to show body part undergoingsurgery - head.	• Same-with Wireless Probe/DRF forOptical System.• Same• Same-with ability to simultaneouslydisplay and/or keep multiple imageson screen, "zoom" images to largersizes, and move images on screen• Same• Same
Materials	• Aluminum 6061 [anodized] for trackingprobe [K853627 for use of anodizedaluminum].• Stainless steel ASTM F899, passivatedQQ-P-35 Type 2 for sterile probe-tips.	• Same• Same
FEATURE	MAYFIELD®/ ACCISS™ Operating Armand Optical ACCISS™ Systems[K955397, K982244]	MAYFIELD®/ ACCISS™ System with"Windows" for Cranial Surgery andMAYFIELD® Optical ACCISS™ Systemwith "Windows" for Cranial Surgeryand with the Wireless Probe/DRF
Sterilization	• Systems shipped non-sterile. Usercleans and sterilizes prior to use.• Steam sterilization method validated formetal components and accessories.	• Same-except for the packaged sterilebatteries for the Wireless Probe/DRFthat are shipped separately.• Same-includes wireless Probe/DRF.
Type of Detector	• Optically encoded signals from joints ofarticulated arm.• A 3-camera Sensor Assembly detectsinfrared signals emitted from LEDs onhand-held probe handle. The SensorAssembly is mounted on a dedicated,mobile stand.• The Probe handle and DRF each haveLEDs that are electrically powered by awire from workstation.	• Same• Same-with Transmitter for WirelessProbe/DRF mounted with SensorAssembly.• Same-except the Wireless Probe/DRFeach carries a sterile battery for power.
RegistrationTechnique	• Scanned Fiducials• Anatomical Fiducials	• Same• Same
OperatingSoftware	• Structure: MS-DOS, with two majorfunctions: Image Importation, andSurgical Applications [navigation].• Uses a Graphical User Interface tofacilitate interaction with users.• Image Manipulation: Unreformatted,reformatted, 3-D surface rendering.	• Structure: "Windows", with same twomajor functions.• Uses Modified Graphical User Interfacewith similar functionality.• Same-with multiple images displayed,"zoom" of image, able to move imageson screen.
Accessories	• BUDDE® Halo Retractor System[K830332]	• Same

Summary of Substantial Equivalence - Comparison Table

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II 510(k) SUMMARY (continued)

Summary of Substantial Equivalence - Comparison Table

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Image /page/4/Picture/1 description: The image shows the logo for the Department of Health & Human Services (HHS). The logo is a circular seal with the words "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" arranged around the perimeter. Inside the circle is an abstract symbol that resembles a stylized caduceus or a bird in flight, composed of three curved lines.

Food and Drug Administration 9200 Corporate Boulevard Rockville MD 20850

NOV - 2 1999

Mr. Kenneth B. Miller Director, Regulatory Affairs/Quality Assurance Ohio Medical Instrument Company, Inc. 4900 Charlemar Drive Cincinnati, Ohio 45227

Re: K992843

Trade Name: MAYFIELD®/ACCISS™ Operating Arm System with Windows NT® for Cranial Surgery and MAYFIELD®/Optical ACCISS™ System (OASYS™) with Windows NT® for Cranial Surgery and with the Wireless Probe/Dynamic Reference Frame

Regulatory Class: II Product Code: HAW Dated: August 20, 1999 Received: August 24, 1999

Dear Mr. Miller:

We have reviewed your Section 510(k) notification of intent to market the device referenced above and we have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to 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). 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.

If your device is classified (see above) into either class II (Special Controls) or class III (Premarket Approval), it may be subject to such additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 895. A substantially equivalent determination assumes compliance with the current Good Manufacturing Practice requirement, as set forth in the Quality System Regulation (QS) for Medical Devices: General regulation (21 CFR Part 820) and that, through periodic (QS) inspections, the Food and Drug Administration (FDA) will verify such assumptions. Failure to comply with the GMP regulation may result in regulatory action. In addition, FDA may publish further announcements concerning your device in the Federal Register. Please note: this response to your premarket notification submission does not affect any obligation you might have under sections 531 through 542 of the Act for devices under the Electronic Product Radiation Control provisions, or other Federal laws or regulations.

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Page 2 - Mr. Kenneth B. Miller

This letter will allow you to begin marketing your device as described in your 510(k) premarket notification. The FDA finding of substantial equivalence of your device to a legally marketed predicate device results in a classification for your device and thus, permits your device to proceed to the market.

If you desire specific advice for your device on our labeling regulation (21 CFR Part 801 and additionally 809.10 for in vitro diagnostic devices), please contact the Office of Compliance at (301) 594-4595. Additionally, for questions on the promotion and advertising of your device, please contact the Office of Compliance at (301) 594-4639. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR 807.97). Other general information on your responsibilities under the Act may be obtained from the Division of Small Manufacturers Assistance at its toll-free number (800) 638-2041 or (301) 443-6597 or at its internet address "http://www.fda.gov/cdrh/dsmamain.html".

Sincerely yours,

Celia M. Witten, Ph.D., M.D. Director Division of General and Restorative Devices Office of Device Evaluation Center for Devices and Radiological Health

Enclosure

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510(k) Number (if known):

Device Name: MAYFIELD®/ACCISS™ Operating Arm System with Windows NT® for Cranial Surgery and MAYFIELD® Optical ACCISS™ System with Windows NT® for Cranial Surgery and with Wireless Probe/Dynamic Reference Frame

Indications for Use:

The MAYFIELD® / ACCISS™ Operating Arm System with Windows NT® for Cranial Surgery and the MAYFIELD®/Optical ACCISS™ System (OASYS™) with Windows NT® for Cranial Surgery and with Wireless ProberDynamic Reference Frame are indicated for use in guidance and localization in open craniotomies, and for surgeries that are traditionally performed with a stereotactic apparatus, such as biopsies, thalamotomies, and electrode implants. The Systems may also be used to review medical images in a neurosurgical context.

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

Concurrence of CDRH, Office of Device Evaluation (ODE)

colle

on,

Prescription Use of (Per 21 CFR 801.109)

Over-The-Counter Use _

(Optional Format - 1 - 2 - 96)

Regulation Number and Section

§ 882.4560 Stereotaxic instrument.

(a)
Identification. A stereotaxic instrument is a device consisting of a rigid frame with a calibrated guide mechanism for precisely positioning probes or other devices within a patient's brain, spinal cord, or other part of the nervous system.(b)
Classification. Class II (performance standards).