The Rhythmlink Disposable Concentric Stimulating Probe is used to perform localized stimulation of neural tissue and to locate, identify and monitor cranial motor nerves, peripheral nerve and spinal nerve roots during surgery. The Rhythmlink Disposable Concentric Stimulating Probe is a single patient use device.
Device Story
Disposable concentric stimulating probe used during surgery to locate, identify, and monitor neural tissue. Device consists of inner stainless steel wire (cathode) and outer stainless steel cannula (anode) isolated by dielectric heat shrink tubing. Input: electrical stimulation from external EMG/EP electroneurodiagnostic equipment. Operation: probe delivers localized electrical current to target nerves; concentric design limits current spread to reduce stimulation of surrounding nerves. Output: measurable neural/muscle response recorded by external equipment. Used by clinicians in surgical settings. Benefits: enables precise nerve localization and monitoring, reducing risk of nerve damage during procedures.
Clinical Evidence
No clinical data. Bench testing only: dimensional measurements, continuity, insulator breakdown (Hi Pot), stimulation delivery, pull-off strength, and leadwire strength. Biocompatibility testing per ISO 10993-1 (cytotoxicity, sensitization, intracutaneous reactivity, pyrogenicity) confirmed the device is non-cytotoxic, non-irritant, and non-pyrogenic.
Technological Characteristics
Concentric probe design; inner wire (cathode) and outer cannula (anode) isolated by dielectric heat shrink. Materials: SST 316/304 shaft, PET insulation, medical grade ABS handle, tin-plated copper leadwires with PVC insulation. Dimensions: 80-330mm shaft length, 1.6mm tip diameter. Connectivity: DIN 42 802 touch-proof connectors for external EMG/EP equipment. Sterilization: Ethylene Oxide (EO).
Indications for Use
Indicated for patients undergoing surgery requiring localization, identification, and monitoring of cranial motor nerves, peripheral nerves, and spinal nerve roots.
Regulatory Classification
Identification
A surgical nerve stimulator/locator is a device that is intended to provide electrical stimulation to the body to locate and identify nerves and to test their excitability.
{0}------------------------------------------------
ﺮ
f
. .
# APR | 1 2014
# 5.0 Traditional 510(k) Summary Disposable Concentric Stimulation Probe
The following 510(k) summary has been prepared pursuant to requirements specified in 21 CFR § 807.92(a).
| 807.92(a)(1)<br>Submitter Information: | Rhythmlink International, LLC<br>1140 First Street South<br>Columbia, SC 29209<br><br>Phone: 803-252-1222<br>FDA Registration #: 1067162<br>Owner Operator #: 9052354 |
|----------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| Official Correspondent: | Daniel McCoy<br>Director of Engineering and Regulatory Affairs<br>Rhythmlink International, LLC<br>1140 First Street South<br>Columbia, SC 29209<br>Phone: 803-252-1222 ext. 102<br>Email: dmccoy@rhythmlink.com |
| Summary Date: | March 6, 2014 |
| 807.92(a)(2)<br>Device Identification: | Proprietary Device Name:<br>Disposable Concentric Stimulating Probe (Trade name has not been finalized at this time)<br><br>Generic Device Name:<br>Surgical Nerve Stimulator/Locator<br><br>Regulatory Class:<br>Class II<br><br>Classification Name:<br>21 CFR §874.1820, Surgical Nerve Stimulator/Locator<br><br>Product Code: ETN |
| 807.92(a)(3)<br>Predicate Device(s): | K103128 Cadwell Disposable Stimulator Probes |
| | |
| Device Description | target nerves and to locally stimulate them in order to provide a measurable<br>response. The stimulus will have a very small current spread to reduce the<br>innervation of the surrounding nerves. |
| | The concentric design has two main parts, an inner stainless steel wire and<br>an outer cannula also insulated from reading un-intended signals. |
| | The Inner wire is isolated from the outer stainless steel cannula using a<br>biocompatible heat shrink tubing. This Inner Wire acts as the stimulator and<br>is surrounded by the outer cannula. The Outer Cannula is isolated with a<br>biocompatible heat shrink which isolates the outer cannula allowing contact<br>in a localized area of the intended nerves of interest. |
| | The inner wire, the cathode, is stimulated using EMG/EP<br>electroneurodiagnostic equipment cleared for the stimulation of nerve<br>tissue and recording muscle activity during surgical procedures (not part of<br>this 510(k) submission) The outer cannula acts as the anode or reference. |
| | The Inner wire and outer cannula are isolated from each other using a<br>dielectric heat shrink and are connected to a color coded pair of leadwires<br>which are terminated by two DIN 42 802 touch proof connectors. The<br>concentric stimulators are terminated on the distal end inside of a plastic<br>handle and are independently connected to the leadwires. |
| 807.92(a)(5)<br>Intended Use(s) | The Rhythmlink Disposable Concentric Stimulating Probe is used to perform<br>localized stimulation of neural tissue and to locate, identify and monitor<br>cranial motor nerves, peripheral nerve and spinal nerve roots during<br>surgery. |
| | The Rhythmlink Disposable Concentric Stimulating Probe is a single patient<br>use device. |
{1}------------------------------------------------
. -'
.
・・
.
{2}------------------------------------------------
. .
r
・・
| 807.92(a)(6)<br>Technological<br>Characteristics | An evaluation of the technological characteristics of the Rhythmlink Disposable Concentric Stimulating Probe where compared to the predicate device, Cadwell Probes. | | |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------------------|
| | Rhythmlink<br>Concentric Probe | Predicate Device<br>Cadwell | |
| | 510(k) Number | K132138 | K103128 |
| | Shaft Length | 80 – 330mm | 80 - 340mm |
| | Handle Length | 100mm | 110mm |
| | Leadwire Length | 1.0m – 3.0m | 2.0m |
| | Tip Diameter/Exposure | $Ø$ 1.6mm x 0.0 – 0.3mm | $Ø$ 1.3mm x 0-0.3mm |
| | Shaft Material | SST 316 and SST 304 | SST 316 |
| | Shaft Insulation | PET | PTFE |
| | Handle Material | Medical Grade ABS | Medical Grade ABS |
| | Lead Wire Material | Tin Plated Copper | Tin Plated Copper |
| | Lead Wire Insulation | Medical Grade PVC | Medical Grade PVC |
| 807.92(b)(1)<br>Summary of Non-Clinical<br>Tests | Non-clinical bench testing was comprised of dimensional measurements and performance tests. Dimensional testing was conducted of the Probe diameter and Probe lengths. Performance testing was conducted and analyzed for a continuity of .5 Ohms, Hi Pot testing of insulator breakdown, stimulation delivery, Pull-off strength and leadwire (patient cables) strength. The device was sterilized under the current, validated EO Sterilization Cycle 93007, and testing for residual EtO and ECH levels determined that the residuals are at the lowest possible limits. | | |
| | Biocompatibility per ISO-10993-1: 1997, Part I "Biological Evaluation of Medical Devices, Evaluation and Testing" was confirmed by analyzing biocompatibility tests on the device (exclusive of the handle and lead wire). The biocompatibility testing is summarized in the table below: | | |
| | Test | Results | Conclusion |
| | ISO BET Get<br>Clot Testing | The system did not interfere with the lysate reaction, and no inhibition or enhancement or enhancement was present. The test articles did not clot at the neat concentration. The geometric mean endpoint concentration of each test article was <0.06 EU/mL and each contained <0.9 EU/Device of bacterial endotoxin. The results are acceptable. | The device is non-pyrogenic. |
| USP Inhibition<br>and<br>Enhancement<br>Testing, Gel<br>Clot Method | The test Concentric<br>Stimulation Probe does not<br>inhibit or enhance the<br>Bacterial Endotoxin Test<br>according to the USP<br>guidelines. | The device is non-<br>pyrogenic. | |
| ISO MEM<br>Elution Test | There was no biological<br>reactivity (Grade 0) of the<br>cells exposed to the test<br>article extract. The response<br>obtained from the positive<br>and negative control article<br>extracts confirmed the<br>suitability of the test system. | The device is non-<br>cytotoxic. | |
| ISO<br>Intracutaneous<br>Reactivity Test | The test article sites did not<br>show a significantly greater<br>biological reaction than the<br>sites injected with the<br>control article. | The device is non-irritant. | |
| Once the verification testing was completed it was confirmed that the<br>proposed Rhythmlink Concentric Stimulation Probes are as safe and<br>effective as the predicate device. | | | |
| 807.92(b)(2)<br>Clinical Tests | There was no clinical testing performed on the proposed device. | | |
| 807.92(b)(3)<br>Clinical Summary | | | |
{3}------------------------------------------------
? ና.
、
、
.
{4}------------------------------------------------
## DEPARTMENT OF HEALTH & HUMAN SERVICES
Public Health Service
Food and Drug Administration 10903 New Hampshire Avenue Document Control Center . We 166 Silver Spring, MD 2005-0002
Image /page/4/Picture/12 description: The image shows a logo with a stylized bird in the center. The bird is composed of three curved lines that suggest movement or flight. Encircling the bird is text that appears to be part of the logo, though the specific words are not clear due to the image quality. The overall design is simple and symbolic, likely representing an organization or entity associated with aviation, freedom, or a similar concept.
# April 11, 2014
Rhythmlink International. L.C. Mr. Daniel E. McCoy Director of Engineering and Regulatory Affairs 1140 First Sireet South Columbia. South Carolina 29209
Re: K132138
> Trade/Device Name: Rhythmlink disposable concentric stimulating probe Regulation Number: 21 CFR 874.1820 Regulation Name: Neurosurgical Nerve Locator Regulatory Class: Class H Product Code: PDQ. ETN Dated: March 1. 2014 Received: March 14, 2014
Dear Mr. McCoy:
We have reviewed vour Section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent ffor 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. Ifsting 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 devicerelated adverse events) (21 CFR 803): good manufacturing practice requirements as set forth in
{5}------------------------------------------------
Page 2 - Mr. Daniel E. McCoy
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 contact the Division of Small Manufacturers. International and Consumer Assistance at its tollfree number (800) 638-2041 or (301) 796-7100 or at its Internet address
http://www.fda.gov/MedicalDevices/Resourcesfor You/Industry/default.htm. 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
http://www.fda.gov/MedicalDevices/Safety/ReportalProblem/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,
# Felipe Aguel -S
Carlos L. Peña, PhD, MS Director Division of Neurological and Physical Medicine Devices Office of Device Evaluation Center for Devices and Radiological Health
Enclosure
{6}------------------------------------------------
## DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration
# Indications for Use
510(k) Number (if known) K132138
Device Name
Disposable Concentric Stimulating Probe
#### Indications for Use (Describe)
The Rhythmlink Disposable Concentric Stimulating Probe is used to perform localized stimulation of neural tissue and to locate, identify and monitor cranial motor nerves, peripheral nerve and spinal nerve roots during surgery.
The Rhythmlink Disposable Concentric Stimulating Probe is a single patient use device.
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)
# PLEASE DO NOT WRITE BELOW THIS LINE - CONTINUE ON A SEPARATE PAGE IF NEEDED.
## FOR FDA USE ONLY
Concurrence of Center for Devices and Radiological Health (CDRH) (Signature)
# 11 - - - Date: 2014.04.11
1 --- 13:51:09 -04'00' 13:51:09 -04'00'
FORM FDA 3881 (1/14)
Form Approved: OMB No. 0910-0120 Expiration Date: January 31, 2017 See PRA Statement on last page.
{7}------------------------------------------------
This section applies only to requirements of the Paperwork Reduction Act of 1995.
# *DO NOT SEND YOUR COMPLETED FORM TO THE PRA STAFF EMAIL ADDRESS BELOW. *
The burden time for this collection of information is estimated to average 79 hours per response, including the time to review instructions, search existing data sources, gather and maintain the data needed and complete and review the collection of information. Send comments regarding this burden estimate or any other aspect of this information collection, including suggestions for reducing this burden, to:
> Department of Health and Human Services Food and Drug Administration Office of Chief Information Officer Paperwork Reduction Act (PRA) Staff PRAStaff(@fda.hhs.gov
"An agency may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a currently valid OMB number."
Predicate graph will load when search results are available.
Embedding visualization will load when search results are available.
PDF viewer will load when search results are available.
Loading panels...
Select an item from Submissions
Click any panel, subpart, regulation, product code, or device to see details here.
Section Matches
Results will appear here.
Product Code Matches
Results will appear here.
Special Control Matches
Results will appear here.
Loading collections...
Loading
My Alerts
You will receive email notifications based on the filters and frequency you set for each alert.
Sort by:
Create Alert
Search Filters
Agent Token
Create a read-only bearer token for Claude, ChatGPT, or other agents that can call HTTP APIs.
Copy this now. It will not be shown again.
Connected apps
Apps you authorized through browser sign-in. Disconnecting revokes their access immediately.
Learn the FDA Browser
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.