K253854 · Orthocon, Inc. · GXP · Jan 2, 2026 · Neurology
Device Facts
Record ID
K253854
Device Name
MONTAGE XT Cranial Cement
Applicant
Orthocon, Inc.
Product Code
GXP · Neurology
Decision Date
Jan 2, 2026
Decision
SESE
Submission Type
Special
Regulation
21 CFR 882.5300
Device Class
Class 2
Attributes
Therapeutic
Indications for Use
MONTAGE XT Cranial Cement is a self-setting calcium phosphate cement indicated for use in the repair of neurosurgical burr holes, contiguous craniotomy cuts, and other cranial defects with a surface area no larger than 25 cm². MONTAGE XT Cranial Cement should be used only in skeletally mature individuals.
Device Story
MONTAGE XT Cranial Cement is a sterile, biocompatible, resorbable material used for cranial defect repair. The device consists of two separate putty components containing granular calcium phosphate, calcium stearate, vitamin E acetate, a triglyceride, a polyalcohol, and a mixture of lactide-diester and polyester-based polymers. Components are manually mixed immediately prior to use to form a settable, putty-like material. The device is applied manually by a surgeon to the defect site. It cures without an appreciable exothermic reaction and is slowly resorbed during the bone remodeling process. The non-calcium salt and non-polymeric components degrade via dissolution; polymers degrade via hydrolysis; calcium salts degrade via chemical dissolution and/or cellular removal. The device provides a 4-minute working time. It is intended for use in a surgical setting.
Clinical Evidence
No clinical studies were conducted. Evidence relies on bench testing and in vivo data from previous submissions (K221933, K233566). Biocompatibility was established per ISO 10993 (cytotoxicity, irritation, sensitization, systemic toxicity, genotoxicity, local tissue toxicity, hemolysis, pyrogenicity, and neurotoxicity). In vivo performance was supported by a rabbit critical size defect model. Working time performance was validated in previous testing.
Technological Characteristics
Two-part putty system; components: granular calcium phosphate, calcium stearate, vitamin E acetate, triglyceride, polyalcohol, lactide-diester/polyester-based polymers. Settable material is primarily calcium phosphate. Manual mixing (45 seconds); 4-minute working time. Sterile, single-patient-use, gamma-irradiated. Resorbable via dissolution, hydrolysis, and cellular removal. No exothermic curing reaction.
Indications for Use
Indicated for repair of neurosurgical burr holes, contiguous craniotomy cuts, and cranial defects ≤ 25 cm² in skeletally mature individuals.
Regulatory Classification
Identification
Methyl methacrylate for cranioplasty (skull repair) is a self-curing acrylic that a surgeon uses to repair a skull defect in a patient. At the time of surgery, the surgeon initiates polymerization of the material and forms it into a plate or other appropriate shape to repair the defect.
MONTAGE-XT Settable, Resorbable Bone Putty (K233566)
Submission Summary (Full Text)
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FDA U.S. FOOD & DRUG ADMINISTRATION
January 2, 2026
ORTHOCON, Inc.
% Alyssa McDermott
Sr. Director, Quality and Regulatory Affairs
Abyrx, Inc.
700 Fairfield Avenue, Suite 1
Stamford, Connecticut 06902
Re: K253854
Trade/Device Name: MONTAGE XT Cranial Cement
Regulation Number: 21 CFR 882.5300
Regulation Name: Methyl Methacrylate for Cranioplasty
Regulatory Class: Class II
Product Code: GXP
Dated: October 27, 2025
Received: December 3, 2025
Dear Alyssa McDermott:
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 (the 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 available 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.
Additional information about changes that may require a new premarket notification are provided in the FDA guidance documents entitled "Deciding When to Submit a 510(k) for a Change to an Existing Device"
U.S. Food & Drug Administration
10903 New Hampshire Avenue
Silver Spring, MD 20993
www.fda.gov
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K253854 - Alyssa McDermott
Page 2
(https://www.fda.gov/media/99812/download) and "Deciding When to Submit a 510(k) for a Software Change to an Existing Device" (https://www.fda.gov/media/99785/download).
Your device is also subject to, among other requirements, the Quality System (QS) regulation (21 CFR Part 820), which includes, but is not limited to, 21 CFR 820.30, Design controls; 21 CFR 820.90, Nonconforming product; and 21 CFR 820.100, Corrective and preventive action. Please note that regardless of whether a change requires premarket review, the QS regulation requires device manufacturers to review and approve changes to device design and production (21 CFR 820.30 and 21 CFR 820.70) and document changes and approvals in the device master record (21 CFR 820.181).
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 Part 803) for devices or postmarketing safety reporting (21 CFR Part 4, Subpart B) for combination products (see https://www.fda.gov/combination-products/guidance-regulatory-information/postmarketing-safety-reporting-combination-products); good manufacturing practice requirements as set forth in the QS regulation (21 CFR Part 820) for devices or current good manufacturing practices (21 CFR Part 4, Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR Parts 1000-1050.
All medical devices, including class I and unclassified devices and combination product device constituent parts are required to be in compliance with the final Unique Device Identification System rule ("UDI Rule"). The UDI Rule requires, among other things, that a device bear a unique device identifier (UDI) on its label and package (21 CFR 801.20(a)) unless an exception or alternative applies (21 CFR 801.20(b)) and that the dates on the device label be formatted in accordance with 21 CFR 801.18. The UDI Rule (21 CFR 830.300(a) and 830.320(b)) also requires that certain information be submitted to the Global Unique Device Identification Database (GUDID) (21 CFR Part 830 Subpart E). For additional information on these requirements, please see the UDI System webpage at https://www.fda.gov/medical-devices/device-advice-comprehensive-regulatory-assistance/unique-device-identification-system-udi-system.
Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR 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-devices/medical-device-safety/medical-device-reporting-mdr-how-report-medical-device-problems.
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K253854 - Alyssa McDermott
Page 3
For comprehensive regulatory information about medical devices and radiation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/medical-devices/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-devices/device-advice-comprehensive-regulatory-assistance/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,
XIAOLIN
ZHENG -S
For Jaime Raben, Ph.D.
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 | | |
| --- | --- | --- |
| Please type in the marketing application/submission number, if it is known. This textbox will be left blank for original applications/submissions. | K253854 | ? |
| Please provide the device trade name(s). | | ? |
| MONTAGE XT Cranial Cement | | |
| Please provide your Indications for Use below. | | ? |
| MONTAGE XT Cranial Cement is a self-setting calcium phosphate cement indicated for use in the repair of neurosurgical burr holes, contiguous craniotomy cuts, and other cranial defects with a surface area no larger than 25 cm². MONTAGE XT Cranial Cement should be used only in skeletally mature individuals. | | |
| Please select the types of uses (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
K253854 Page 1 of 3
# General Company Information
Name: Orthocon, Inc.
Contact: Alyssa McDermott
Sr. Director of Quality and Regulatory Affairs
Address: 700 Fairfield Avenue – Suite 1
Stamford, CT 10533
Telephone: (855) 475 - 9175
Date Prepared: December 29, 2025
# General Device Information
Product Name: MONTAGE XT™ Cranial Cement
Common Name: Calcium Phosphate Cranial Cement
Classification: Class II
Product codes: GXP
Regulation: 21 CFR 882.5300
# Primary Predicate Device
Orthocon: Montage™ Settable Resorbable Bone Putty
[510(k) Number K221933]
# Reference Predicate Device:
Orthocon, Inc. MONTAGE-XT Settable, Resorbable Bone Putty
[510(k) K233566]
# Device Description
MONTAGE XT Cranial Cement is a sterile, biocompatible, resorbable material for use in repair of cranial defects. The MONTAGE XT Cranial Cement comprises of two separate components of putty consistency containing granular calcium phosphate, calcium stearate, vitamin E acetate, a triglyceride, a polyalcohol and a mixture of lactide-diester and polyester-based polymers. When mixed together, the components of the MONTAGE XT Cranial Cement form a putty-like material. The resulting hardened, resorbable material is primarily calcium phosphate and is slowly resorbed during the remodeling process. Montage XT components must be mixed immediately prior to use.
# Indications for Use
MONTAGE XT Cranial Cement is a self-setting calcium phosphate cement indicated for use in the repair of neurosurgical burr holes, contiguous craniotomy cuts, and other cranial defects with a surface area no larger than 25 cm². MONTAGE XT Cranial Cement should be used only in skeletally mature individuals.
The following table shows comparisons of characteristics of the MONTAGE XT Cranial Cement and the predicate device.
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SUBSTANTIAL EQUIVALENCE INFORMATION
K253854 Page 2 of 3
Comparisons of Technological Characteristics
| MONTAGE XT Cranial Cement K253854 | Montage Settable, Resorbable Bone Putty Predicate 510(k) - K221933 |
| --- | --- |
| Device is intended for use in the repair of neurosurgical burr holes, contiguous craniotomy cuts and other cranial defects with a surface area no larger than 25 cm². | Device is intended for use in the repair of neurosurgical burr holes, contiguous craniotomy cuts and other cranial defects with a surface area no larger than 25 cm². |
| At the time of application, device is in the form of a putty-like material. | At the time of application, device is in the form of a putty-like material. |
| Device is designed to be manually applied to the cranial defect. | Device is designed to be manually applied to the cranial defect. |
| MONTAGE XT Cranial Cement is formulated as a two-part putty/putty device that forms a “settable” (hardening) material when manually mixed at the time of surgery. | Montage Settable, Resorbable Bone Putty is formulated as a two-part putty/putty device that forms a “settable” (hardening) material when manually mixed at the time of surgery. |
| Sterile mixture of two separate components of putty-like consistency comprised of granular calcium phosphate, calcium stearate, vitamin E acetate, a triglyceride, polyalcohols and a mixture of lactide-diester and polyester-based polymers. The MONTAGE XT Cranial Cement is to be mixed immediately prior to use. Resulting settable material from the two putties is primarily comprised of calcium phosphate. | Sterile mixture of two separate components of putty-like consistency comprised of granular calcium phosphate, calcium stearate, vitamin E acetate, a triglyceride, polyalcohols and a mixture of lactide-diester and polyester-based polymers. Montage is to be mixed immediately prior to use. Resulting settable material from the two putties is primarily comprised of calcium phosphate. |
| Implanted device is resorbable in greater than 30 days primarily due to presence of calcium phosphate. | Implanted device is resorbable in greater than 30 days primarily due to presence of calcium phosphate. |
| The non-calcium salt and non-polymeric components degrade via dissolution; the polymer degrades via hydrolysis and calcium salts degrade via chemical dissolution and/or cellular removal. | The non-calcium salt and non-polymeric components degrade via dissolution; the polymer degrades via hydrolysis and calcium salts degrade via chemical dissolution and/or cellular removal. |
| Single-patient-use device is provided sterile by gamma irradiation. | Single-patient-use device is provided sterile by gamma irradiation. |
| The bone putty is available in individual and/or multi-pack patient use sizes. | The bone putty is available in individual and/or multi-pack patient use sizes. |
| Each putty is placed into a separate inner foil “blister” which are contained within a single outer foil pouch. The outer foil pouch contains a desiccant. The inner blister and outer pouch are heat sealed and sterilized. | Each putty is placed into a separate inner foil “blister” which are contained within a single outer foil pouch. The outer foil pouch contains a desiccant. The inner blister and outer pouch are heat sealed and sterilized. |
| Mixing for homogeneity takes 45 seconds. | Mixing for homogeneity takes 45 seconds. |
| Material is settable following application. | Material is settable following application. |
| Material provides a working time of 4 minutes. | Material provides a working time of 2 minutes. |
| Device cures with no appreciable exothermic reaction. | Device cures with no appreciable exothermic reaction |
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K253854 Page 3 of 3
# Testing Completed
## Biocompatibility Testing
Testing was previously conducted under K221933 to evaluate the device's biocompatibility in accordance with the recommendations of ISO 10993. The following biocompatibility studies were conducted on the final, finished, gamma-irradiation sterilized Montage device and in accordance with the good laboratory practice (GLP) requirements: cytotoxicity, irritation, sensitization, systemic toxicity, genotoxicity, local tissue toxicity, hemolysis, pyrogenicity and neurotoxicity; please see Montage Settable Resorbable Bone Putty 510(k) Number K221933. Based on a risk assessment, no additional testing is needed to support the biocompatibility of the MONTAGE XT Cranial Cement.
## In Vivo Testing
The MONTAGE-XT Settable, Resorbable Bone Putty was compared to the predicate Montage in a rabbit critical size defect model under K233566 and was found to be substantially equivalent to Montage when used as a bone void filler device. Based on a risk assessment, no additional testing is needed to support the safety and performance of the MONTAGE XT Cranial Cement.
## Performance Data
Testing was previously conducted under K220315 to confirm working time of 4 min and equivalent device performance. Based on a risk assessment, no additional testing is needed to support the safety and performance of the MONTAGE XT Cranial Cement.
## Clinical Testing
No clinical studies have been conducted in support of this 510(k).
## Conclusion
This submission supports the position that the Orthocon MONTAGE XT Cranial Cement is substantially equivalent to the predicate device.
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.