GI Endoscopy · 1 min read
Over-The-Scope Clips (OTSC): Defect Closure Mechanisms
Clinical Bottom Line
| Closure Modality | Mechanical Grip | Ideal Clinical Application |
|---|---|---|
| Standard TTS Hemoclip | Jaws approximate the mucosal layer (superficial pinch). | Controlling small arterial bleeding or closing minor post-EMR mucosal defects. |
| OTSC (Over-The-Scope Clip) | Massive nitinol "bear-trap" grasping the entire full-thickness wall. | Definitive closure of frank luminal perforations, fistulas, or massive hemorrhage from fibrotic duodenal ulcers. |
The Shift to Full-Thickness Suturing
While standard Through-The-Scope (TTS) hemoclips are excellent for drawing two edges of flexible mucosa together, they frequently fail when deployed into dense, rigid, fibrotic tissue (such as a chronic peptic ulcer base) or when attempting to close massive structural perforations. The Over-The-Scope Clip (OTSC)—frequently branded as the "Bear Claw"—revolutionized therapeutic endoscopy by generating massive compressive force capable of securing the full thickness of the bowel wall.
Deployment Strategy
Unlike a TTS clip, the OTSC requires the endoscope to be completely removed from the patient to physically stretch the massive, primed nitinol clip over the outside distal tip of the camera (similar to a variceal band ligator). The endoscopist navigates the armed scope to the massive defect, suctions the entire perforation directly into the distal cap (or utilizes a heavy twin-grasper device to pull the dense edges in), and fires the clip. The nitinol memory instantly springs the jaws shut with immense force, permanently sealing the defect and frequently saving the patient from an emergency open laparotomy.
Clinical guidelines summarized by the Gastroscholar Research Team. Last updated: 2026. This article is intended for physicians.
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