Gastroscholar

Over-the-scope does not mean one device. Ovesco OTSC is a bear-trap that loads through the channel and can use a twin grasper. Padlock is a hexagonal star that rides outside the scope, deploys with a thumb button, and cannot be cut off with remOVE. In a standardized spurting model, OTSC held 120 mmHg in 11 of 11 applications and Padlock held none. That is a preclinical gap, not a human RCT. Use OTSC when the job is a vessel. Use Padlock when you need the channel and a circumferential close.

Original GastroScholar summary card for Padlock versus OTSC. Not an endoscopic photograph.
Original GastroScholar summary card. Not an endoscopic photograph. No reuse-cleared device still was available, so this page does not invent one.

Experienced teaching points

Clinical Pearls

  1. OTSC: hinged nitinol, channel occupied, twin grasper available, remOVE cutter exists.
  2. Padlock: six inner prongs, cable outside the scope, channel free, not removable once fired.
  3. Prosst 2017 EASIE model: OTSC 11/11 hemostasis at 120 mmHg, Padlock 0/11, mean hold 9 mmHg.
  4. Human OTSC bleeding RCT lives at the OTSC page. There is no head-to-head human Padlock RCT.

GI Endoscopy · 7 min read

Padlock vs OTSC: Same Cap Idea, Different Clip, Different Job

Two cap-mounted nitinol clips. OTSC has twin graspers and randomized bleeding data. Padlock keeps the working channel and closes in a ring.

Clinical Bottom Line

Question Practical answer
Are Padlock and OTSC the same tool? No. Both are cap-mounted nitinol. Geometry, deployment, channel use, and the bleeding data are different.
Which one for a fibrotic ulcer or Dieulafoy? Ovesco OTSC. Twin grasper, compressive jaws, and a 190-patient RCT as first-line therapy in selected NVUGIB. Detail: OTSC bleeding page.
Which one when you still need the channel? Padlock. The firing cable runs outside the scope. Suction, then thumb-button. Useful for some fistulas and selected defects.
Can I take Padlock off if I miss? No remOVE equivalent. OTSC can be cut. Do not fire Padlock as a rehearsal.
TTS first? Yes for a small, nonfibrotic vessel or a zipper-able EMR defect. TTS page.

How do the clips actually differ?

Ovesco OTSC (Tübingen) is the older cap clip. The clip sits in a cap. A fabric string runs through the working channel to a hand wheel. You can park a twin grasper or an anchor through that same channel, pull tissue into the cap, and fire. A dedicated cutter (remOVE) can fragment a misplaced clip. That is why OTSC became the default language for "put a big clip on a bad vessel."

Padlock (Aponos, later Steris / US Endoscopy) is a hexagonal star with six inward prongs. The delivery cable rides along the outside of the insertion tube, so the channel stays free. You suction tissue into a shallower cap and press a button. The ring cinches circumferentially. Two cap sizes exist: a gastroscope Defect Closure cap and a deeper Pro-Select colonoscope cap. Once it lands, it stays.

Those mechanics matter more than the marketing. A hinged jaw can gather a vessel if you can face it. A radial star wants a plug of tissue in the cap. Tangential ulcers punish both. Fibrotic bases punish Padlock more if you cannot suction a bite.

What is the hemostasis evidence?

Prosst and Kratt (PMID 28350273) randomized OTSC versus Padlock on a standardized Forrest Ia model in the EASIE simulator. Primary endpoint: hold 120 mmHg after a technically correct fire. OTSC: 11/11. Padlock: 0/11. Mean pressure resistance 300 mmHg (assay ceiling) versus 9.2 mmHg. That is not a human trial. It is the only randomized comparison, and it is not subtle.

Human Padlock reports are small and uncontrolled. Dinelli (PMID 28435855) used Padlock in 14 patients for fistulas, two perforations, two post-polypectomy bleeds, and six suction-EFTR cases. Deployment failed in an angulated duodenal perforation; TTS clips closed it. Armellini (PMID 28135728) closed a recognized duodenal perforation with Padlock after a twin grasper pulled the edges in. Those are existence proofs, not a reason to swap OTSC out of the bleeding cart.

Barkun 2023 (PMID 36877964) is the OTSC bleeding RCT: 30-day further bleeding 3.2% versus 14.6% with standard therapy in 190 adults. That number does not transfer to Padlock. If the lesion is a vessel, reach for OTSC unless the device is not in the room.

When is Padlock the smarter cap?

  • You need the working channel during capture (guidewire, grasper that is not the OTSC twin, suction plus irrigation).
  • The target is a fistula or a flat defect that will suction as a plug, not a spurting artery on a fibrotic crater.
  • The endoscope diameter matches the Padlock cap chart. Wrong cap, failed fire.

Do not use either cap clip as a delay tactic. If the lesion will not face the cap, stop and call IR. Surgery stays in reserve. That pathway is on the OTSC bleeding page.

Selected references

  1. Prosst RL, Kratt T. A randomized comparative trial of OTSC and Padlock for upper GI hemostasis in a standardized experimental setting. Minim Invasive Ther Allied Technol. 2017;26:65-70.
  2. Dinelli M, et al. First clinical experiences with a novel endoscopic over-the-scope clip system. Endosc Int Open. 2017;5:E151-E156.
  3. Armellini E, Crino SF, Orsello M, et al. Successful endoscopic closure of iatrogenic duodenal perforation with the new Padlock Clip. Endoscopy. 2017;49:E54-E55.
  4. Barkun AN, et al. OTSC versus standard endoscopic treatment as initial therapy in nonvariceal upper GI bleeding. Ann Intern Med. 2023.

Last reviewed September 20, 2026. Written for clinicians choosing a cap clip for a defect or a bleed, and for the ones who think Padlock is just a cheaper OTSC.

Topics

For your teaching file

Save this article as a PDF

Drop your email and we'll open a print-ready version you can save as a PDF — and you'll start getting our weekly GI endoscopy newsletter.

Save as PDF

Padlock Clips vs. OTSC: Advanced Defect Closure Comparisons

Enter your email — we'll open a clean print-ready version of this article. Choose Save as PDF in the print dialog to download.

Free, no spam. Gastroscholar newsletter. Unsubscribe anytime.

← All articles