NEW GENERATION ENDOSCOPIC CLIPS FOR FULL-THICKNESS DEFECT CLOSURES: A COMPARATIVE EX-VIVO, PORCINE STUDY

Background
Endoscopic closure techniques have a rapidly emerging role in the management of transmural gastrointestinal defects and have been shown to be effective and safe. Through-the-scope clips (TTSC), over-the-scope clips (OTSC) and a novel endoscopic helix tacking and suture device are currently available for endoscopic full-thickness closure. However, there is a paucity of data regarding the comparative effectiveness of these tools. In this study, we aimed to evaluate the closure strength of these devices in an ex-vivo porcine stomach model.

Methods
We tested the closure strength of four endoscopic closure devices: a novel TTS clip with anochor prongs (Mantis*), an endoscopic helix tacking and suture system (X-Tack*), a conventional rotatable TTS clip (Resolution 360*), (*Boston Scientific, Marlborough, MA), and
an over-the-scope clip (OTSC, Ovesco Endoscopy USA, Cary, NC). A standardized, 1.5cm full-thickness, linear incision was made in the greater curvature of the gastric body and then subsequently closed by each device under optimal conditions. Leak pressure testing was performed by modifying a sphygmomanometer to a non-collapsable catheter placed in an inflated pig stomach. All luminal openings were closed using surgical clamps to create a sealed pressure chamber. After closure, each specimen was submerged in water, and the pressure required to achieve air leakage was recorded. This was repeated 3 times for each closure device.

Results
A total of 12 gastric closures were conducted (3 per device). The average leak pressure of the conventional rotatable TTSCs, novel TTSC with anochor prongs, OTSCs and helix tacking and suture system were 67.0 ± 8.5mmHg, 89.7 ± 5.4mmHg, 96.0 ± 7.2mmHg, and 55.7 ± 8.3 mmHg respectively (Figure 1). Pairwise comparisons using the Holm’s correction revealed that the novel TTSC with anochor prongs and OTSC both had significantly higher leak pressures than the conventional rotatable TTSCs (P = 0.016, P = 0.005) and the helix tacking and suture system (P = 0.002, P < 0.001). The leak pressure for the novel TTSC with anochor prongs and OTSCs were not significantly different.

Conclusion
Our results show the novel TTSC with anochor prongs and OTSCs achieved comparable gastric perforation closure in this ex-vivo porcine model, and both performed better than other commonly used endoscopic closure devices. This is the first study to compare these devices and may aid endoscopists in selecting the optimal tool when faced with a perforation. Further study is required to determine how factors including defect size, anatomic location, and the viability of the surrounding tissue affect performance.