K991835 · Stl Intl., Inc. · ITH · Dec 20, 1999 · Physical Medicine
Device Facts
Record ID
K991835
Device Name
HANG UPS POWER II
Applicant
Stl Intl., Inc.
Product Code
ITH · Physical Medicine
Decision Date
Dec 20, 1999
Decision
SESE
Submission Type
Traditional
Regulation
21 CFR 890.5900
Device Class
Class 2
Attributes
Therapeutic
Indications for Use
The InvertAlign is a non-invasive traction device that utilizes gravity to apply traction. The traction force is a result of the natural force of gravity, and is affected only by the user's body weight and angle of invertAlign is indicated to increase intervertebral dimensions, to decrease pressure on the intervertebral discs, to stretch and relax muscles, and to temporarily relieve back pain associated with the listed conditions.
Device Story
InvertAlign is a motorized, gravity-assisted traction table. User stands on platform, secures ankles in foam-padded clamps, and reclines. Motorized controls allow user or supervisor to adjust inversion angle; device can stop at any angle or exceed 90 degrees for full inversion. Emergency crank provided for manual return during power loss. Device uses gravity and user body weight for traction; no mechanical force applied to body. Intended for use in clinic or home settings to stretch weight-bearing joints (ankles, knees, hips, spine) and relieve back pain. Benefits include non-invasive, natural traction and reduced user error compared to manual inversion tables.
Clinical Evidence
No clinical data provided. Bench testing only. Safety and effectiveness supported by historical use of inversion therapy since the 1960s and comparison to legally marketed predicate devices.
Technological Characteristics
Gravity-assisted traction table. Motorized tilt mechanism with emergency manual ascension crank. Foam-padded ankle clamps for user securement. Operates via user body weight and inversion angle. No mechanical force applied to body. Standalone device.
Indications for Use
Indicated for individuals seeking gravity-assisted traction to increase intervertebral dimensions, decrease intervertebral disc pressure, stretch/relax muscles, and temporarily relieve back pain.
Regulatory Classification
Identification
Powered traction equipment consists of powered devices intended for medical purposes for use in conjunction with traction accessories, such as belts and harnesses, to exert therapeutic pulling forces on the patient's body.
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DEC 2 0 1999
# 510(k) Summary for Hang Ups InvertAlign
K991835
| Submitter: | Roger C. Teeter<br>Hang Ups Div. of STL International, Inc.<br>10004 - 162nd St. Ct. E<br>Puyallup, WA 98375<br>Phone: (253) 840-5252<br>Fax: (253) 840-5757 | | |
|-----------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------|---------------------------------|
| Contact: | Same as above. | | |
| Date prepared: | December 17, 1999 | | |
| Name of device: | Hang Ups InvertAlign | | |
| Common or Usual Name: | Rotation-Powered Gravity-Assisted Traction Table<br>Inversion Table | | |
| Classification Name: | Equipment, Traction, Powered | | |
| Predicate Devices: | F5000-Series<br>InverChair<br>Vax-D<br>ATT-300<br>Midland Vari-trac II | 510(k) Exempt<br>K821002<br>K951622<br>K944699<br>K862746 | HST<br>ITH<br>ITH<br>ITH<br>ITH |
#### Device Description:
The InvertAlign is a non-invasive traction device that utilizes gravity to apply traction. The user straddles the main shaft of the InvertAlign and while resting his seat on the base of the table frame, the user places each foot on the foot platform. The user's ankles slide between the foam padded ankle clamps. In the InvertAlign's full upright position, the user will be reclined in the supine position at approximately 10 degrees off vertical. By pulling the locking pin and locking the clamps securely to the ankles, the user or supervisor is able to manually adjust the foam clamps to form a secure but comfortable fit. The user or supervisor may then use the tilt control button to increase / decrease the angle of inversion. The InvertAlign can be stopped at any angle and is able to tilt beyond ninety degrees from horizontal to allow the user to hang and move freely at full inversion.
#### Intended Use:
The InvertAlign is a non-invasive traction device that utilizes gravity to apply traction. The traction force is a result of the natural force of gravity, and is affected only by the user's (510(k) Summary, cont.)
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pg 4 96
body weight and angle of invertAlign is indicated to increase intervertebral dimensions, to decrease pressure on the intervertebral discs, to stretch and relax muscles, and to temporarily relieve back pain associated with the listed conditions. Explanations for these claims are found in Appendix C.
### Technological Characteristics:
The InvertAlign is a gravity-assisted traction device. The traction force applied to the body is a measure of the user's weight and angle of inversion. The InvertAlign itself does not apply a mechanical force to the body. The device to which the InvertAlign is most similar is the F5000III Inversion Table. Essentially, the only difference between these two devices is that the InvertAlign is operated by a motor. The InvertAlign tilts with the help of motorized controls, whereas the F5000II uses the body's arm movements to control the angle of inversion. With the motor, this upgraded inversion table no longer requires the users to adjust the table to individual height settings, reducing the possibility of user error.
Another device to which the InvertAlign is very similar is the InverChair. The main difference between these two devices is the body position in which the device places the user. The InverChair is a motorized device which inverts the patient in a 90/90 position (seated). The InvertAlign inverts the user in a standing, supine position. By allowing for a full-body inversion experience, the InvertAlign gives the body a chance to stretch and perform body-enhancing exercises.
The other three devices to which the InvertAlign is compared, the Vax-D, ATT-300, and Midland Vari-trac II, physically apply a traction force to the body. This is the vital difference between these devices and the InvertAlign the InvertAlign allows for a natural form of traction, whereas the Vax-D, ATT-300, and Midland Vari-trac II make use of a mechanically applied form of traction. The InvertAlign is a safer alternative form of traction because it relies on gravity and the user's body weight to apply the traction force. The InvertAlign is easy to use and does not require the help of a medical supervisor to operate. The InvertAlign may be returned upright at any time and requires only one user-sensitive adjustment-the foot clamps must be fitted to the users' ankles.
#### Summary of Safety and Effectiveness:
Inversion has been used since the age of Hypocrites and has been widely accepted as a natural form of traction in the United States since the 1960's. The fundamental purpose of the Hang Ups InvertAlign is to permit the application of inversion to the ankles, knees, hips and spine (all weight-bearing joints). The important attributing to the safety and effectiveness of the device include the easy-to-use controls which require only one user-specific adjustment (i.e.: adjustable ankle clamps), the moderate, controlled rate of inversion and ascension, and the use of gravity to apply a natural and non-invasive traction force to weightbearing joints. The emergency ascension crank may be used in the event of a power outage to return the user to an upright position.
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# DEPARTMENT OF HEALTH & HUMAN SERVICES
Image /page/2/Picture/2 description: The image shows the logo for the U.S. Department of Health & Human Services. The logo consists of a circular seal with the text "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" around the perimeter. Inside the circle is a stylized image of an eagle with three wing-like shapes.
AUG 2 5 2000
Food and Drug Administration 9200 Corporate Boulevard Rockville MD 20850
Mr. Roger C. Teeter STL International, Inc. 10004 - 162nd Street, Ct. E. Puyallup, Washington 98375
Re: K991835 Trade Name: Hang Ups InvertAlign Regulatory Class: II Product Code: ITH Dated: December 17, 2000 Received: December 17, 2000
Dear Mr. Teeeter:
This letter corrects our substantially equivalent letter of December 20, 1999, which incorrectly identified your device as a prescription use device on the indications for use enclosure.
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 control provisions of the Act. The general control provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration.
If your device is classified (see above) into either class II (Special Controls) or class III (Premarket Approval), it may be subject to such additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 895. A substantially equivalent determination assumes compliance with the current Good Manufacturing Practice requirement, as set forth in the Quality System Regulation (QS) for Medical Devices: General regulation (21 CFR Part 820) and that, through periodic (QS) inspections, the Food and Drug Administration (FDA) will verify such assumptions. Failure to comply with the GMP regulation may result in regulatory action. In addition, FDA may publish further announcements concerning your device in the Federal Register. Please note: this response to your premarket notification submission does not affect any obligation you might have under sections 531 through 542 of the Act for devices under the Electronic Product Radiation Control provisions, or other Federal laws or regulations.
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
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Page 2 - Mr. Roger C. Teeter
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 CFF) Part 801 and If you desire specific advice for your devices), please contact the Office of Compliance at (301) 594-4659. Additionally, for questions on the promotion and advertising of your device, (301) 594-4037. Additionally, for quee at (301) 594-4639. Also, please note the regulation prease contact the Office or Comphanes as (as a ) Dotification" (21 CFR 807.97). Other general entitled, "Misoraliding by releveles to promation hours be obtained from the Division of Small information on your responsionnes ander the new now (301) 443-6597, or at its Internet address "http://www.fda.gov/cdrh/dsmamain.html".
Sincerely yours,
Neville Jackson
4- Celia M. Witten, Ph.D., M.D. Director Division of General, Restorative and Neurological Devices Office of Device Evaluation Center for Devices and Radiological Health
Enclosure
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## Statement of Indications for Use
510(k) Number (if known): K991835
Device Name:__________________________________________________________________________________________________________________________________________________________________
Indication for Use:
Hang Ups InvertAlign is intended to be used for inversion, a method of gravity-assisted traction that utilizes the user's own body weight. Inversion is indicated of gray intervertebral dimentions, decrease pressure on the intervetebral discs, stretch and relax muscles, and temporarily relieve back pain associated with the listed contitions.
(PLEASE DO NOT WRITE BELOW THIS LINE--CONTINUE ON ANOTHER PAGE IF NEEDED Concurrence of CDRH, Office of Device Evaluation (ODE)
Prescription Use (Pcr 21 CFR 801.109)
OR
Over-the-Counter Use
Arnold Sager
(Division Sign-Off) Division of Cieneral Restorative Devices 510(k) Number _
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Image /page/5/Picture/1 description: The image shows the seal of the Department of Health & Human Services (HHS) of the United States. The seal features a stylized depiction of an eagle with three wings, symbolizing health, services, and human concerns. The text "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" is arranged in a circular pattern around the eagle.
Public Health Service
DEC 2 0 1999
Food and Drug Administration 9200 Corporate Boulevard Rockville MD 20850
Mr. Roger C. Teeter STL International, Inc. 10004 - 162nd Street, Ct. E. Puyallup, Washington 98375
Re: K991835 Trade Name: Hang Ups InvertAlign Regulatory Class: II Product Code: ITH Dated: December 17, 1999 Received: December 17, 1999
Dear Mr. Teeter:
We have reviewed your Section 510(k) notification of intent to market the device referenced above and we have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (Act). You may, therefore, market the device, subject to the general controls provisions of the Act. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration.
If your device is classified (see above) into either class II (Special Controls) or class III (Premarket Approval), it may be subject to such additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 895. A substantially equivalent determination assumes compliance with the current Good Manufacturing Practice requirement, as set forth in the Quality System Regulation (QS) for Medical Devices: General regulation (21 CFR Part 820) and that, through periodic (QS) inspections, the Food and Drug Administration (FDA) will verify such assumptions. Failure to comply with the GMP regulation may result in regulatory action. In addition, FDA may publish further announcements concerning your device in the Federal Register. Please note: this response to your premarket notification submission does not affect any obligation you might have under sections 531 through 542 of the Act for devices under the Electronic Product Radiation Control provisions, or other Federal laws or regulations.
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.
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Page 2 - Mr. Roger C. Teeter
If you desire specific advice for your device on our labeling regulation (21 CFR Part 801 and additionally 809.10 for in vitro diagnostic devices), please contact the Office of Compliance at (301) 594-4595. Additionally, for questions on the promotion and advertising of your device, please contact the Office of Compliance at (301) 594-4639. Also, please note the regulation entitled, "Mishranding by reference to premarket notification" (21 CFR 807.97). Other general information on your responsibilities under the Act may be obtained from the Division of Small Manufacturers Assistance at its toll-free number (800) 638-2041 or (301) 443-6597 or at its internet address "http://www.fda.gov/cdrh/dsmamain.html".
Sincerely yours,
tocoe
Jim È. Dillard III Acting Director Division of General and Restorative Devices Office of Device Evaluation Center for Devices and Radiological Health
Enclosure
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.