Endoscopic clip systems for hemostasis and defect closure in gastrointestinal endoscopy

Table 1 Features of through-the-scope clips

Feature	Importance
Open width	Determines the width of tissue grasp; distance between the distal teeth when the clip is opened to the maximum
Stem/tail length	Affects reach, especially in deeper lesions; also important to consider on narrow areas
Rotatability	Allows precise positioning
Overshoot	Rotation exceeding 30 degrees after stopping
Open-close mechanism	Allows repositioning of clips prior to deployment
Tensile strength	Grasp of the clip to the apposed mucosa

Table 2 Limitations of through-the-scope clips

Limitation	Description
Mechanical factors
Shallow bite with mucosal capture only	Scarred or edematous bases (e.g., fibrotic ulcers, post-ESD beds) reduce tissue grip, so closure or hemostasis may be unreliable - particularly for larger defects (> 10-15 mm) or tangential targets. In these settings, OTSC or suturing may be preferable than TTS[10,61]
Device or handling constraints	Some TTS clips are one-shot at deployment (limited recapture) and with imprecise rotational control. Likewise, multiple clips increase time, cost, and lumen clutter, hindering additional therapy[2,11]
Misfires resulting to technical and safety risks	Misfires resulting to opposite-wall capture or serosal injury can occur with off-axis closure. In addition, accessories may be entrapped (e.g., loop/snare) or mucosa torn if traction is applied after partial closure
Clip migration and dwell time variability	Clips usually detach within weeks (animal and clinical data often cite 1-4 weeks), but prolonged retention can occur (reports up to 3-5 years), which may also create MRI-compatibility considerations depending on the clip[14,62-64]
Lesion factors
Difficult access or angle	Locations such as the cardia, lesser curve, and posterior duodenal wall limit perpendicular apposition and precise jaw placement; long/looped positions also cause suboptimal rotation[2]
Brisk bleeding and clot burden	Active arterial bleeding can obscure the field and prevent adequate tissue capture; thermocoagulation or combination therapy is preferred when clip compression alone is insufficient[2,11,34]
Large vessels and wide defects	Clip compressive force may be inadequate for thick-caliber bleeding vessels or defects > 1-2 cm, where OTSC or even suturing has higher durable success[10,61]
Performance in specific etiologies	For colonic diverticular bleeding, meta-analyses show higher early rebleeding with clipping vs EBL, underscoring TTS limitations in these types of lesions[35]

TTS: Through-the-scope; ESD: Endoscopic submucosal dissection; OTSC: Over-the-scope clip; MRI: Magnetic resonance imaging; EBL: Endoscopic band ligation.

Table 3 Steps in deployment of an over-the-scope clip

Steps	Ovesco clip (Ovesco Endoscopy)	Padlock (STERIS)
Set up the device	Attach hand wheel to biopsy port; inspect cap/clip and release thread	Attach external trigger/cable; inspect cap/clip; and confirm trigger function
Mount the cap on the endoscope and route actuation	Preload clip on transparent cap; route release thread through the working channel to hand wheel	Preload clip on cap; route actuation cable externally, leaving the working channel free
Prepare target site	Irrigate and adequately visualize the lesion	Same as Ovesco
Orient correctly	Center the lesion near the working-channel. Advance with cap over target; adjust torque or insufflation for a perpendicular approach	Same as Ovesco
Capture tissue	Use suction and/or Anchor or Twin Grasper; draw edges into cap	Use suction and grasping device via free channel to pull edges into cap more easily
Fire the clip	Rotate hand wheel to tension thread and deploy (similar to esophageal variceal band ligation mechanism)	Squeeze external trigger to deploy; no channel thread
Verify closure	Confirm apposition and hemostasis; irrigate or gently probe with a water jet	Same as Ovesco
Know when to escalate	If closure or hemostasis incomplete, add thermal/adjunct clips or place a second OTSC; consider suturing	Same as Ovesco

OTSC: Over-the-scope clip.

Table 4 Examples of clinical scenarios and approach to clipping

Clinical scenario	Recommended approach to clipping
Oozing ulcer-base bleeding	Optimize visualization with irrigation and/or dilute epinephrine. Apply a reopenable TTS clip to the culprit vessel. Combine with thermal or inject-and-clip therapy if the base is fibrotic. Escalate after 2-3 well-placed clips without control[8]
Hemostasis in narrow-lumen anatomy or pediatrics	Use short-stem clips (e.g., Steris, MicroTech). Maintain modest insufflation, and take small incremental grasps to avoid opposite-wall capture. Confirm blanching before clip release[17,18]
Small perforation closure	Clear the target area. Perform an edge-to-center zipper closure with high-force, reopenable TTS clips in small, perpendicular bites. Escalate early to OTSC if closure remains incomplete[78]
Closure after EMR/ESD	Perform an edge-to-center zipper closure using reopenable, rotatable, high-force clips. For wide defects, pre-approximate with MANTIS or DAT and complete with long-span clips. The ROLM technique using clip with eyelet and nylon line may aid closure of large defects[79]. Consider prophylactic closure in the duodenum or cecum. Escalate to OTSC or suturing if closure is suboptimal[7,78]
Training or general use	Prioritize reopenable, rotatable clips that tolerate multiple repositioning. Use a standardized checklist: Target centered, perpendicular approach, suction-assisted grasp, blanching confirmed before release, and adhere to stop rules[17]

TTS: Through-the-scope; EMR: Endoscopic mucosal resection; ESD: Endoscopic submucosal dissection; DAT: Dual action tissue clip; ROLM: Reopenable clip-over-the-line method; OTSC: Over-the-scope clip.