A comparison of two endoscopic closures: over-the-scope clip (OTSC) versus KING closure (endoloop + clips) in a randomized long-term experimental study

Background Both over-the-scope clip (OTSC) and KING (endoloop + clips) closures provide reliable and safe full-thickness endoscopic closure. Nevertheless, OTSC clip demonstrated significantly inferior histological healing in the short-term follow-up. Aim To compare OTSC versus KING closure of a perforation with regard to long-term effectiveness and macroscopic and histological quality of healing. Methods We performed a randomized experimental study with 16 mini-pigs (mean weight 43.2 ± 11.2 kg). A standardized perforation was performed on the anterior sigmoid wall. KING closure ( n = 8) was attained by approximation of an endoloop fixed to the margins of a perforation with endoclips. OTSC closure ( n = 8) was performed by deploying OTSC (OVESCO) over the defect. Pigs underwent a control sigmoidoscopy 8 months after the closure to assess the macroscopic quality of healing. Then, autopsy was performed and the rectosigmoid was sent for histopathological assessment. Results All closures were completed successfully without air leaks. The duration of closure was similar in both techniques (OTSC 17.8 ± 7.6 min vs. KING 19.6 ± 8.8 min). At autopsy, all KING closures (100 %) were healed with a flat scar without signs of leakage. Microscopically, no inflammatory changes were observed after KING closure. In the OTSC group, microscopic ulcers were present in two pigs (25 %), cryptal abscesses in three pigs (38 %) and significant neutrophil accumulation in all eight pigs ( P