The Midas Rex MR8 Depth Stop attachment and tools are indicated for the incision, cutting, removing, and drilling of soft and hard tissue during cranial surgical procedures with the intent to create a hole through the cranium to allow surgeons access to desired surgical locations and/or to facilitate insertion, placement of other surgical devices during such procedures.

Device Description

The Midas Rex MR8 Depth Stop attachment and tools are intended to create a cranial access hole of a known diameter and depth.

AI/ML Overview

This document (K213454) is a 510(k) premarket notification for a medical device and, as such, does not contain the detailed information necessary to answer all aspects of your request regarding acceptance criteria and a study that proves the device meets those criteria.

Specifically, this submission focuses on demonstrating substantial equivalence to a predicate device, rather than providing a comprehensive study protocol and results for a new device's performance against specific acceptance criteria. The document states that "The changes from the predicate, do not raise any new issues of safety and effectiveness" and that "The following testing was conducted to demonstrate that the modifications to the subject devices are as safe and effective as the predicate." This implies that the focus was on validating that the changes did not degrade performance, and the existing predicate device's performance serves as the benchmark.

Therefore, many of the questions asked cannot be directly answered from the provided text.

Here's an attempt to extract what is available and explain what is missing:

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

The document does not provide a table of acceptance criteria and reported device performance in the way you've requested. Instead, it describes a comparison to a predicate device to demonstrate substantial equivalence. The "performance" is primarily implied by the claim that the technological characteristics are similar and that conducted testing (Product Life Verification, Summative Validation, Biocompatibility Testing) supports the functionality, integrity, and safety and effectiveness for its intended use, making it "as safe and effective as the predicate."

The closest thing to "acceptance criteria" discussed are the aspects compared to the predicate, as shown in the table on pages 5-6. However, these are comparative features, not quantified performance criteria with acceptance thresholds.

Feature	Subject Device (Midas Rex™ MR8™ Depth Stop System) Performance (as presented)	Acceptance Criteria (implied/compared to predicate)
Sponsorship	Medtronic Powered Surgical Solutions	Identical to Predicate
Product Code	HBE	Identical to Predicate (HBE)
Drill System	Pneumatic, Electric	Identical to Predicate
Operating Principle	(Not explicitly stated, assumed to be rotational drilling)	Identical to Predicate
Intended Use	Create a cranial access hole of a known diameter and depth.	Identical to Predicate
Indications for Use	Incision, cutting, removing, and drilling of soft and hard tissue during cranial surgical procedures to create a hole through the cranium.	Identical to Predicate
System Components	Electric Handpieces, Pneumatic Handpieces, Attachments, Surgical Dissecting Tools	Identical to Predicate
Patient Contacting Components	Attachments, Surgical Dissecting Tools	Identical to Predicate
Attachment Materials	Stainless Steel, Aluminum, Ceramic, Phenolic, Epoxy, Chrome Coated Brass, Polymeric	Identical to Predicate
Attachment Configuration	Straight, Variable	Identical to Predicate
Attachment Tube Length	12.8cm (retracted), 14.5cm (exposed)	Equivalent to Predicate (13.7cm/14.8cm); argument made that difference does not impact performance or safety.
Sterilization Method – Reusable	Steam	Identical to Predicate
Surgical Dissecting Tool Materials	Tool Steel	Identical to Predicate
Dissecting Tool Tip Style	Twist Drill	Equivalent to Predicate (Twist Drill); minor modifications without impact on safety/performance.
Dissecting Tool Overall Length	17-22cm	Identical to Predicate
Dissecting Tool Head Diameter	2.1 – 7.5 mm	Identical to Predicate
Packaging – Sterile Dissecting Tools	Individually packaged in clear plastic capped tube within polypoly pouch. Tube cap is blue.	Equivalent to Predicate; predicate cap is yellow, otherwise identical.
Sterilization Method – Single Use	Gamma with minimum radiation dose of 25 kGy	Identical to Predicate
Shelf Life – Dissecting Tools	5 Years	Identical to Predicate
Extended Depth Setting	Up to 20mm (new feature)	Not applicable as a direct comparison to predicate, but implied acceptance would be that this extension also functions safely and effectively. (This implies a new "performance" aspect not listed in the main comparison table).
New Task in User Workflow	(Not detailed)	Not applicable as a direct comparison. Implied acceptance is that this new task is also safe and effective.

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

The document mentions "Product Life Verification," "Summative Validation," and "Biocompatibility Testing." However, it does not specify sample sizes for any of these tests, nor does it provide information on the data provenance (e.g., country of origin, retrospective or prospective). Given the nature of a 510(k) for a mechanical device modification, these would likely be engineering and bench testing, not clinical studies in the typical sense.

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

This information is not provided in the document. The testing described (Product Life, Summative Validation, Biocompatibility) are typically engineering validation tests, not clinical studies requiring expert ground truth in the context of diagnostic AI.

4. Adjudication method for the test set

This information is not provided. As above, the described testing types do not typically involve adjudication methods for "ground truth" derived from expert consensus.

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

No MRMC study was done or mentioned. This device is a surgical drill accessory, not an AI software/diagnostic device.

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

Not applicable. This device is a mechanical surgical tool component, not an algorithm.

7. The type of ground truth used

The concept of "ground truth" in the way it's typically applied to AI or diagnostic studies (expert consensus, pathology, outcomes data) is not relevant or discussed for this type of mechanical device submission. The "ground truth" for this device would be established by engineering specifications, material properties, and mechanical performance tests.

8. The sample size for the training set

Not applicable. This is a mechanical device, not an AI/machine learning product that requires a training set.

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

Not applicable. As above, this is a mechanical device.

Summary of Findings from the Document:

The K213454 submission demonstrates substantial equivalence primarily by:

Comparing the subject device's features and intended use to a legally marketed predicate device (K191597).
Highlighting that the differences are minor (e.g., extended depth setting, minor tool head geometry, new user task, compatibility with MR8 system) and do not raise new safety or effectiveness concerns.
Stating that risk management (ISO 14971:2019) was conducted and found no new risks.
Reporting that specific engineering tests were conducted: "Product Life Verification," "Summative Validation," and "Biocompatibility Testing," which "demonstrate that the functionality, integrity, and safety and effectiveness of the subject devices are sufficient for their intended use."

The document's purpose is to show that the modified device is "as safe and effective" as the already cleared predicate, rather than to establish new, distinct performance criteria and demonstrate achievement of those from scratch.

Summary

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November 23, 2021

Medtronic Powered Surgical Solutions Carrie Eddings Principal Regulatory Affairs Specialist 4620 North Beach Street Fort Worth, Texas 76137

Re: K213454

Trade/Device Name: Midas Rex MR8 Depth Stop Attachment, Midas Rex MR8 Depth Stop Tool 2.4mm, Midas Rex MR8 Depth Stop Tool 3.2mm, Midas Rex MR8 Depth Stop Tool 3.2mm Long, Midas Rex MR8 Depth Stop Tool 7.5mm Regulation Number: 21 CFR 882.4310 Regulation Name: Powered Simple Cranial Drills, Burrs, Trephines, And Their Accessories Regulatory Class: Class II Product Code: HBE, HBB, HBC Dated: October 22, 2021 Received: October 26, 2021

Dear Carrie Eddings:

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. Although this letter refers to your product as a device, please be aware that some cleared products may instead be combination products. The 510(k) Premarket Notification Database located at https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm identifies combination product submissions. 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.

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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 of medical device-related adverse events) (21 CFR 803) for devices or postmarketing safety reporting (21 CFR 4, Subpart B) for combination products (see https://www.fda.gov/combination-products/guidance-regulatory-information/postmarketing-safety-reportingcombination-products); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820) for devices or current good manufacturing practices (21 CFR 4, Subpart A) for combination products; 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 https://www.fda.gov/medical-device-safety/medical-device-reportingmdr-how-report-medical-device-problems.

For comprehensive regulatory information about medical devices and radiation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/medicaldevices/device-advice-comprehensive-regulatory-assistance) and CDRH Learn (https://www.fda.gov/training-and-continuing-education/cdrh-learn). 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 (https://www.fda.gov/medical-device-advice-comprehensive-regulatoryassistance/contact-us-division-industry-and-consumer-education-dice) for more information or contact DICE by email (DICE@fda.hhs.gov) or phone (1-800-638-2041 or 301-796-7100).

Sincerely.

Adam D. Pierce, Ph.D. Assistant Director DHT5A: Division of Neurosurgical, Neurointerventional and Neurodiagnostic Devices OHT5: Office of Neurological and Physical Medicine Devices Office of Product Evaluation and Quality Center for Devices and Radiological Health

Enclosure

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Indications for Use

510(k) Number (if known) K213454

Device Name

Midas Rex MR8 Depth Stop Attachment (MR8-ASDS01 ); Midas Rex MR8 Depth Stop Tool 2. 4mm (MR8-DS1TD24); Midas Rex MR8 Depth Stop Tool 3.2mm (MR8-DS1TD32);Midas Rex MR8 Depth Stop Tool 3.2mm Long (MR8-DS1TD32L); Midas Rex MR8 Depth Stop Tool 7.5mm (MR8-DS1TD75)

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

November 23, 2021

Company: Medtronic Powered Surgical Solutions 4620 North Beach Street Fort Worth, Texas 76137 Telephone Number: (817) 788-6400
Carrie Eddings (Primary) Contact: Principal Regulatory Affairs Specialist Telephone Number: (214) 384-0606 Email: carrie eddings(@medtronic.com

Kyle Hoefling (Alternate) Senior Regulatory Affairs Manager Telephone: (760) 207-2432 Email: kyle.d.hoefling(@medtronic.com

Proprietary Trade Name: Midas Rex MR8 Depth Stop Attachment and Tools Common Name: MR8 Depth Stop System Classification Name: Powered cranial drills, burrs, trephines, and their accessories (21 CFR 882.4310) Classification: Class II Product Code: HBE Primary Predicate: Midas Rex Legend Depth Stop Attachment and Tools, K191597

Product Description:

The Midas Rex MR8 Depth Stop attachment and tools are intended to create a cranial access hole of a known diameter and depth.

Indications for Use:

The Midas Rex MR8 Depth Stop attachment and tools are indicated for the incision, cutting. removing, and drilling of soft and hard tissue during cranial surgical procedures with the intent to create a hole through the cranium to allow surgeons access to desired surgical locations and/or to facilitate insertion, placement of other surgical devices during such procedures.

Comparison of the Technological Characteristics:

There have been no significant changes to the Midas Rex™ Legend Depth Stop Attachment and Tools since prior clearance in K191597.

The subject device, Midas Rex™ MR8™ Depth Stop Attachment and Tools, are to be used with the MR8TM High-Speed Drill Systems and the Stealth Autoguide™ System to create

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cranial access holes of specific diameter and depth as previously cleared through K191597 for the Midas Rex™ Legend Depth Stop Attachment and Tools.

Changes from the predicate include:

Compatibility with the predicate MR8 Drill Systems included within K181535 .
. Extended depth setting to 20mm
Minor modifications to tool head geometry ●
Adding a new task in the user workflow .

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Feature	Subject Device (Midas Rex™MR8™ Depth Stop System)	Predicate Device (Midas Rex™ Legend™Depth Stop System, K191597)	Equivalence Discussion
Sponsor	Medtronic Powered SurgicalSolutions	Medtronic Powered Surgical Solutions	Identical
Product Code	HBE	HBE, HBC, HBB	Identical
Drill System	• Pneumatic• Electric	• Pneumatic• Electric	Identical
Operating Principle			Identical
Intended Use	The Midas Rex MR8 Depth Stopsystem is intended to create acranial access hole of a knowndiameter and depth.	The Midas Rex Legend Depth Stop system isintended to create a cranial access hole of aknown diameter and depth.	Identical
Indications for Use	The Medtronic Midas Rex MR8Drill System is indicated for theincision, cutting, removing, anddrilling of soft and hard tissueduring cranial surgical procedureswith the intent to create a holethrough the cranium to allowsurgeons access to desiredsurgical locations and/or tofacilitate insertion, placement ofother surgical devices during suchprocedures.	The Medtronic Midas Rex Legend Drill Systemis indicated for the incision, cutting, removing,and drilling of soft and hard tissue during cranialsurgical procedures with the intent to create ahole through the cranium to allow surgeonsaccess to desired surgical locations and/or tofacilitate insertion, placement of other surgicaldevices during such procedures.	Identical
Systemcomponents	• Electric Handpieces• Pneumatic Handpieces• Attachments• Surgical Dissecting Tools	• Electric Handpieces• Pneumatic Handpieces• Attachments• Surgical Dissecting Tools	Identical
Patient ContactingComponents	• Attachments• Surgical Dissecting Tools	• Attachments• Surgical Dissecting Tools	Identical
AttachmentMaterials	Stainless Steel, Aluminum,Ceramic, Phenolic, Epoxy,Chrome Coated Brass, Polymeric	Stainless Steel, Aluminum, Ceramic, Phenolic,Epoxy, Chrome Coated Brass, Polymeric	Identical
AttachmentConfiguration	Straight, Variable	Straight, Variable	Identical
Feature	Subject Device (Midas Rex™MR8™ Depth Stop System)	Predicate Device (Midas Rex™ Legend™Depth Stop System, K191597)	Equivalence Discussion
Attachment TubeLength	12.8cm (tube retracted)14.5cm (tube exposed)	13.7cm (tube retracted)14.8cm (tube exposed)	EquivalentThe attachment tube length isinherent due to the overall design ofMR8 attachments and does notimpact the performance or safety ofthe device.
SterilizationMethod – ReusableAttachment	Steam	Steam	Identical
Surgical DissectingTool Materials	Tool Steel	Tool Steel	Identical
Dissecting ToolTip Style	Twist Drill	Twist Drill	EquivalentMinor tool tip modifications whichdo not impact safety or performance.
Dissecting ToolOverall Length	17-22cm	17-22cm	Identical
Dissecting ToolHead Diameter	2.1 – 7.5 mm	2.1 – 7.5 mm	Identical
Packaging – SterileDissecting Tools	Individually packaged in a clearplastic capped tube placed withina polypoly pouch	Individually packaged in a clear plastic cappedtube placed within a polypoly pouch	EquivalentThe packaging is identical except forthe tube cap. On the predicate deviceit is yellow, and on the subjectdevice, the tube cap is blue.
SterilizationMethod – SingleUse Tools	Gamma with minimum radiationdose of 25 kGy	Gamma with minimum radiation dose of 25 kGy	Identical
Shelf Life –Dissecting Tools	5 Years	5 Years	Identical

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Discussion of the Performance Testing:

The intended use of the subject devices, Midas Rex™ MR8™ Depth Stop Attachments and Tools and predicate are identical, and their technological characteristics are similar. The subject devices are a line extension to the MR8 Drill System (K183515) in the same way that the predicate device was a line extension to the Legend Drill Systems (K163182 and K170312). The changes from the predicate, do not raise any new issues of safety and effectiveness.

Risk management was conducted in accordance with ISO 14971:2019 and did not identify any new risks when compared to the predicate. The following testing was conducted to demonstrate that the modifications to the subject devices are as safe and effective as the predicate.

. Product Life Verification
Summative Validation .
. Biocompatibility Testing

Results of these tests demonstrate that the functionality, integrity, and safety and effectiveness of the subject devices are sufficient for their intended use, indications for use and support a determination of substantial equivalence.

Conclusions

The Midas Rex™ MR8™ Depth Stop Attachment and Tools have shown through comparison to be substantially equivalent to the identified predicate devices.

Regulation Number and Section

§ 882.4310 Powered simple cranial drills, burrs, trephines, and their accessories.

(a)
Identification. Powered simple cranial drills, burrs, trephines, and their accessories are bone cutting and drilling instruments used on a patient's skull. The instruments are used with a power source but do not have a clutch mechanism to disengage the tip after penetrating the skull.(b)
Classification. Class II (performance standards).