K964229 · Compass Intl., Inc. · HAW · Aug 19, 1997 · Neurology
Device Facts
Record ID
K964229
Device Name
REGULUS NAVIGATOR
Applicant
Compass Intl., Inc.
Product Code
HAW · Neurology
Decision Date
Aug 19, 1997
Decision
SESE
Submission Type
Traditional
Regulation
21 CFR 882.4560
Device Class
Class 2
Indications for Use
The Regulus™ Navigator (RN) is an intraoperative guidance device which uses reference markers or anatomical references to localize the surgical field. The RN is for intra/extracranial usage.
Device Story
Regulus Navigator (RN) is an intraoperative surgical guidance system. Inputs: preoperative CT/MRI images and physical reference markers/anatomical points selected in the OR. Operation: surgeon selects corresponding points in OR space and image space to calculate a transformation matrix; system maps RN instrument location onto diagnostic images. Output: interactive cursor display on workstation monitor showing instrument position relative to anatomy. Used in OR by surgeons for intra/extracranial procedures. Features include tip location (single/MPR), tip's eye view (cine loop), and trajectory projection. Benefits: provides real-time visual guidance to assist surgeon during procedures, potentially improving accuracy and surgical planning.
Clinical Evidence
Clinical registration testing conducted on 221 patients undergoing conventional surgery for intra/extracranial pathology. Primary endpoint: registration accuracy. Results: overall mean accuracy of 2.56mm (SD 1.15mm); 97% of cases had registration accuracy ≤5mm. No adverse safety or effectiveness reports. Non-clinical bench testing included 12 CT phantom tests (mean error 1.02mm) and 9 MRI phantom tests (mean error 1.67mm).
Technological Characteristics
System includes magnetic field digitizer, computer workstation, and surgical instruments (pointer/suction tips). Uses CT/MRI imaging data. Features multiplanar reconstruction (MPR) and cine loop software. Accuracy measured via RMS transformation error. Connectivity includes RS-232 cables. Accessories include radiolucent adhesive markers, headholder adaptors, and test phantoms.
Indications for Use
Indicated for intraoperative guidance to localize a surgical field for intra/extracranial procedures. Contraindicated for patients with metal objects implanted in the head when using MRI data.
Regulatory Classification
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.
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COMPASS INTERNATIONAL
Cancale Business Park • 919 37th Avenue NW • Rochester, MN 55901
K964229
AUG 19 1997
# 510(k) SUMMARY*
of
# SAFETY and EFFECTIVENESS
## A. General Information
Submitter's Name: COMPASS International, Inc.
Address: 919 37th Avenue NW
Rochester, MN 55901
Telephone: 507-281-2143
Fax: 507-281-1736
Contact Person: Debrah A. Fisher, RAC
Date Prepared: August 14, 1997
## B. Device
Name: Regulus™ Navigator
Trade Name: Regulus™ Navigator
Common Name: Intraoperative Guidance Device
Classification Name: Stereotactic Instrument
Product Code: 84 HAW
Class: II
## C. Identification of Predicate Devices
The Regulus Navigator (RN) as described in this submission is substantially equivalent to the Regulus Measurement Unit (RMU), K935456, which is currently manufactured and marketed by COMPASS International, Inc. The RN also incorporates some of the features that were previously provided by the COMPASS Stereotactic Positioning System, K871046.
The RN incorporates components that are substantially equivalent in function and accuracy to other legally marketed devices including the ISG Family of Viewing Wands, K960714.
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REGULUS NAVIGATOR
510(k) Summary of Safety and Effectiveness
## D. Description of the Device
### 1. Description:
The Regulus Navigator (RN) incorporates preoperative CT and MRI images into a surgical computer system. A minimum of three points (reference markers or anatomical points) are selected with the RN on the patient in the operating room (OR space) and the corresponding locations on the images (image space) are determined and selected by the surgeon. These corresponding points in the OR space and the image space are utilized to calculate a “transformation matrix” which is used to transform the location of the RN instrument into the image space. The location of the RN instrument is interactively displayed as a cursor on the diagnostic images and then used as a tool to guide the surgeon during the intra/extracranial procedure.
The Regulus Navigator has many components and accessories. Components are pieces of the RN which are necessary to perform any surgical procedure. Accessories are additional equipment that allow for adaptation to other surgical systems (COMPASS Stereotactic System, etc.), enable another registration method and provide for phantom maintenance testing.
### Regulus Navigator Components
**Magnetic Field Digitizer** -- the location of the surgical field can be defined in the digitizer’s coordinate system using the RN, providing the basic function of a conventional stereotactic system. Registration of CT and/or MRI images to the digitizer coordinate system (in OR space) requires locating “reference locations” in the images whose location can be determined in the digitizer’s coordinate system in the operating room.
**Regulus Treatment Planning Software** -- software that allows a surgeon to pick target points and define tumor boundaries from radiological data and interactively track instrument location. Features include:
**Tip Location (single and MPR)**: this function allows the positioning of an instrument anywhere in the surgical field and view its corresponding location on the closest pixel on closet CT or MRI images in interactive fashion (can be done with single slice or multiplanar reconstructions).
**Tips-Eye View (single and cine loop)**: this function allows the projection of an instrument’s trajectory onto either the currently Active target slice or all of the images in a series in a cine loop.
**Computer Workstation** -- a computer system which runs the treatment planning software and displays CT/MRI images.
**Regulus Instruments** -- the RN utilizes instruments such as a pointer tip and/or a suction tip.
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REGULUS NAVIGATOR
510(k) Summary of Safety and Effectiveness
## Regulus Navigator Accessories
Accessories include -- radiolucent adhesive radiographic markers (to affix to a patient’s head as fiducial markers), a locking mobile metal cabinet for housing the magnetic field digitizer and computer workstation, a mobile wheel stand, a 3 Point Pinion headholder adaptor, a transmitter mount, a yoke assembly (for use with the COMPASS Stereotactic System only), RS-232 cables and a CT/MRI Test Phantom (for testing accuracy of the RN system)
The design, materials, manufacturing processes and specifications of the RN are similar to the legally marketed device, the Regulus Measurement Unit (RMU) and do not raise any unresolved issues relating to safety and/or effectiveness.
## E. Intended Use Statement
The Regulus™ Navigator (RN) is an intraoperative guidance device which uses reference markers or anatomical references to localize the surgical field. The RN is for intra/extracranial usage.
## F. Substantial Equivalence
The RN is substantially equivalent to the Regulus Measurement Unit (RMU) and the ISG Viewing Wand in terms of its technology, accuracy and intended uses. A direct comparison of significant technology characteristics for these predicate devices and the RN is summarized below. Differences that exist between these devices, relating to technical specifications, materials, physical appearance and design do not affect the relative safety and effectiveness of the RN.
### Technological Characteristics Summary/Comparison Table
Regulus Measurement Unit (RMU) -- legally marketed predicate device, K935456
ISG Viewing Wand - legally marketed predicate device, K960714
Regulus Navigator (RN) -- 510(k) Submission, K964229
| Parameter | RMU | ISG Viewing Wand | RN |
| --- | --- | --- | --- |
| Headframe | Yes | No | No |
| Skull Clamp | No | Yes | Yes |
| Magnetic Field Digitizer | Yes | No | Yes |
| Reference Markers or Anatomical Points | Yes | Yes | Yes |
| Number of Markers/Points | 3 | Unknown | 3 or more |
| Instrument Orientation/Tip Position | Yes | Yes | Yes |
| Software | Yes | Yes | Augmented |
| Transformation Error | RMS | RMS | RMS |
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REGULUS NAVIGATOR
510(k) Summary of Safety and Effectiveness
| Comparison Table Cont. | RMU | ISG Viewing Wand | RN |
| --- | --- | --- | --- |
| CT Imaging | Yes | Yes | Yes |
| MRI Imaging | Yes | Yes | Yes |
| DSA (Digital Subtraction Angiography) Imaging | Yes | No | No |
| Pre-operative Planning of Surgical Procedure | Yes | Yes | Yes |
| Intra-operative Guidance | Yes | Yes | Yes |
| Cross-sections for Manipulation and Guidance | Yes | No | No |
| Multiplanar Reconstruction Software Feature | No | Yes | Yes |
| Bench Testing | Yes | Yes | Yes |
| Clinicals | 31 Subjects | Yes | 221 Subjects |
| Tip Location Software Feature | Yes | Yes | Yes |
| Tip’s Eye View Software Feature | Yes | No | Yes |
| Cine Loop Software Feature | Yes | Unknown | Yes |
| Peripheral Options | Yes | Yes | Yes |
| Memory (image manipulation) | Yes | Yes | Yes |
| Interfaces (data input) | Yes | Yes | Yes |
| O.R. Viewing | Yes | Yes | Yes |
| Environmental Conditions (temperature/vibration) | Yes | Yes | Yes |
| Regulations | Yes | Yes | Yes |
| Dimensions (specifications) | Yes | Yes | Yes |
| Archiving Methods | Yes | Yes | Yes |
| Lesion Location | Superficial Cranial | Cranial | Intra/Extra Cranial |
| Accuracy - Phantom Testing | Mean of 2.10mm | Mean of 1-2mm* | Mean of 1.02mm (CT)
Mean of 1.67mm (MR) |
| Accuracy - Clinical Registration Testing | Mean of 2.78mm | Mean of 2.51mm* | Mean of 2.56mm |
*Eric P. Sipos, M.D., Scot A. Tebo, B.S., S. James Zinreich, M.D., Donlin M. Long, M.D., Ph.D., Henry Brem, M.D., "In Vivo Accuracy Testing and Clinical Experience with the ISG Viewing Wand", Neurosurgery, Vol. 39, No. 1, July 1996.
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REGULUS NAVIGATOR
510(k) Summary of Safety and Effectiveness
## G. Performance Data
### 1. Standards
Currently there are no applicable Performance Standards established by FDA under section 514 of the Food, Drug and Cosmetic Act
### 2. Non-Clinical Tests
Twelve phantom tests were performed utilizing CT scans. The average three-dimensional error over all twelve phantom tests was 1.02mm with a standard deviation of 0.16mm. Nine phantom tests were performed utilizing MRI scans. The average three-dimensional error over all nine phantom tests was 1.67mm with a standard deviation of 0.42mm. Therefore, the non-clinical testing of the RN supports the claim of substantial equivalence.
### 3. Clinical Registration Tests
In clinical registration testing (221 patients), the RN demonstrated an overall mean accuracy of 2.56mm with a standard deviation of 1.15mm. Registration accuracy was 5mm or less in 97% of cases.
Patients requiring conventional surgery of intra/extracranial pathology were included in the study. The only exclusion criteria was any patient with a metal object implanted in the head would be excluded from the use of MRI data in the procedure.
There were no adverse safety and/or effectiveness reports during this clinical study.
COMPASS International, Inc. believes the data in this submission supports the claim of substantial equivalence to the predicate devices.
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DEPARTMENT OF HEALTH & HUMAN SERVICES
Public Health Service
Food and Drug Administration
9200 Corporate Boulevard
Rockville MD 20850
AUG 19 1997
Ms. Debrah A. Fisher
Regulatory Affairs/Clinical Monitoring Assistant
COMPASS International, Inc.
919 37th Avenue, NW
Rochester, Minnesota 55901
Re: K964229
Trade Name: Regulus Navigator (RN)
Regulatory Class: II
Product Code: 84HAW
Dated: July 28, 1997
Received: July 29, 1997
Dear Ms. Fisher:
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 Good Manufacturing Practice for Medical Devices: General (GMP) regulation (21 CFR Part 820) and that, through periodic GMP 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
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Page 2 - Ms. Debrah A. Fisher
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.
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) 594-4648. 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 at (301) 443-6597.
Sincerely yours,

Thomas J. Callahan, Ph.D.
Director
Division of Cardiovascular, Respiratory, and Neurological Devices
Office of Device Evaluation
Center for Devices and Radiological Health
Enclosure
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510(k) Number: K964229
Device Name: Regulus™ Navigator
Indications for Use:
- Intraoperative Guidance Device to Localize a Surgical Field for Intra/Extracranial Usage
PLEASE DO NOT WRITE BELOW THIS LINE -
CONTINUE ON ANOTHER PAGE IF NEEDED
Concurrence of CDRH, Office of Device Evaluation (ODE)
Thomas J. Callahan
(Division Sign-Off)
Division of Cardiovascular, Respiratory, and Neurological Devices
510(k) Number K964229
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Two short videos show you everything — or skip straight to the written tutorial if you'd rather read. You can reopen this any time from the Tutorial button in the top bar.
Part 1 — Search, results, and everyday workflows 16 min
Part 2 — Embeddings: the galaxy map 3 min
1. Search: exact and fuzzy
Type a phrase like "coronary artery calcification" into the search box. You get two kinds of results. Exact results match the literal phrase — prefix searches work ("coronary artery calcificati") but suffix searches do not. Fuzzy results match on the meaning and intent of your phrase rather than the exact words, and are sorted by relevance score. Hover over the Exact or Fuzzy badge on any row to see exactly why it matched.
Use the checkboxes above the results to narrow: SaMD keeps only software-only devices, AI / ML keeps only devices with AI.
Exact vs. fuzzy search: what's the difference?
Exact matches on the literal phrase (prefix search works, suffix does not). Fuzzy matches on the meaning and intent of the phrase rather than the exact words. Hover over the badge on any row to see why it matched.
You search "coronary artery calcification" and want only software devices with AI. What two filters do you apply?
Narrow by SaMD (software-only devices), then narrow by AI/ML (devices with AI).
2. The results table
Scroll right in the results table. The intended use is extracted for you — no need to open the PDF. The device story gives a high-level snapshot of what the device does and how it's used. The AI Performance sub-table shows each output name, acceptance criteria, observed values, and development/test dataset descriptions — the same format Innolitics uses for regulatory strategy outputs, and the fastest high-level fingerprint of an AI device. It is AI-generated but has been very reliable in practice.
Where do you find a device's intended use without opening the PDF?
Scroll right in the search results table. The intended use column is extracted for you; no need to dig into the 510(k) summary PDF.
What does the AI Performance sub-table show, and why is it useful?
Output name, acceptance criteria, observed values, development dataset description, and test dataset description. It's the same format we use for regulatory strategy output and Fast 510(k) input, and the fastest high-level fingerprint of an AI device. AI-generated but reliable in practice.
3. Judging fuzzy relevance
Fuzzy results trail off in relevance as you scroll. Use three signals to decide how far down to go: the fuzzy badge explanations, the intended use column, and whether your target output (e.g., Cobb angle) still appears in the AI Performance sub-table. Once it stops appearing, you're past the relevant zone. A top hit with a low score (~0.4) and a stretched explanation is a hint the closest predicates are far away — the project may be headed for De Novo. Note the fuzzy search is a pattern match: it doesn't handle negation ("not") well, and hardware devices can appear — filter by SaMD/AI ML to cut them.
How do you judge how far down fuzzy search results to go?
Use the relevancy signals: the fuzzy badge explanations, the intended use column, and whether the target output (e.g., Cobb angle) still appears in the AI Performance sub-table. Once it stops appearing, results are trailing off in relevancy.
4. Device detail page: chat and citations
Click a device name to open its detail page: device facts on the left, a chat window on the right. Ask something like "Describe the training data". The answer carries little citation bubbles — click one to jump to the highlighted passage in the source PDF, so you can verify every AI answer against the document. There's also a Download PDF button for sharing.
How do you verify an AI chat answer on the device detail page?
Click the citation bubbles to jump to the relevant highlight in the source document.
Reading rule for every project: how many summaries do you read in full?
At least the three most relevant 510(k) or De Novo summaries, in full. After that, use targeted chat questions to confirm your memory quickly. The tool supports this professional habit — it doesn't replace it.
5. Side-by-side comparison
Select multiple rows in the results table (aim for under ~10), then open the PDF Viewer tab. Ask one question — it goes to all selected devices in parallel, each with citations. This is the fastest way to compare and contrast devices: training data, PCCP scope, how they handled adding new scanners, and so on.
What does the side-by-side PDF viewer mode do?
Select multiple devices, open the PDF viewer tab, and ask one question (e.g., "Describe the training data"). It queries all selected devices simultaneously with citations, so you can compare and contrast quickly.
6. Collections
With rows selected, go to the Collections tab and create a labeled collection (e.g., "Cobb Angle Project"). Reload that selection any time — before a client call, pull up the collection and ask questions across all of its devices at once.
How do you save a set of selected devices for later use?
Select the rows, go to the Collections tab, and create a labeled collection (e.g., "Cobb Angle Project"). You can reload the selection anytime and carry it into the PDF viewer and other tabs that support selections.
7. Product codes and the regulations tree
Click a product code in the results to jump to it in the regulations tree — identification text, sibling product codes, and devices you can open in a PDF viewer on the right. Click a regulation number to see its identification, special controls, and related product codes. You can also search by product code or regulation number at the top of the tree. Always read the special controls if any exist for your device — it broadens your search and sharpens pre-kickoff research.
What can you do from the regulations tree view?
Browse product codes and regulation numbers, read the identification text and special controls, browse sibling product codes, open device PDFs on the right, and search by product code or regulation number at the top of the tree.
8. Chart view
Click Show Chart and segment by regulation number (or product code) to see which regulations dominate your result set. Clicking a regulation takes you into the regulations tree. Great for spotting that most matches are, say, hardware laparoscopic devices — a cue to go back and filter.
How do you see which regulations dominate a search result set?
Click "Show Chart" and segment by Regulation Number. Clicking a regulation takes you to the regulations tree.
9. The predicate graph
Open the Predicates tab for a family-tree view of predicate relationships. Click a node to trace its parents and children; selections from search carry over pre-selected. Commonly predicated devices are worth reading — a lot of people predicated them for a reason. The visual lineage is also handy on client calls, e.g. to show how a predicate family evolved and justify why your predicate still holds.
In the predicate graph, why are commonly predicated devices worth reading?
A lot of people predicated them for a reason. Clicking a node traces parents and children, and selections from search carry over pre-selected.
10. Embeddings: the galaxy map
The Embeddings tab plots every matching document in a 2-D "galaxy map" where semantically similar devices cluster together. Hover or click clusters to explore, and let AI label the clusters for you. Embeddings beat product codes for grouping: two devices can carry different product codes (LLZ vs. QIH) yet do the same thing — the embedding captures the meaning of the intended use and device story. This is also exactly how retrieval-augmented generation (RAG) works under the hood, and it makes a great visual on client calls.
Try it yourself
Head to the search page and work through a few of these AI/ML fuzzy searches to build intuition: perivascular fat on CT · aortic valve calcification opportunistic screening on noncontrast CT · breast cancer prediction on digital pathology slides · autism detection · gestational age prediction · a hearing aid that can also detect a pulse · foundation model based analysis of ECG · large language models · penetration test. Watch how the relevance scores, intended use, and AI Performance tables tell you when results stop being meaningful.