We developed a suturing method with a slip-knot string and clips for a single-channel endoscope. The feasibility of the slip-knot clip suturing method was evaluated in this clinical pilot study.

Ten patients underwent endoscopic submucosal dissection for colorectal and duodenal tumors 5 cm or less. A slip-knot loop can be tightened when tension is applied to the free end of the string. A clip and string can be passed through an instrument channel (3.2 mm) of a single-channel endoscope. The slip-knot loop is anchored onto the mucosal defect’s proximal margin with the clip. Additional clips anchoring the slip-knot loop are placed at the opposite side of the margin. The slip-knot loop is tightened by pulling the string. Additional clips are placed to achieve complete closure.

The mean size of resected specimen was 34.4 ± 10.0 mm. The success rate of the slip-knot clip suturing method was 90% (9/10). In the first patient, the string was cut because of friction, and the patient dropped out of the study. After the failure of the first patient, we used wet string to reduce friction, and slip-knot string worked effectively. The mean procedure time was 18.2 ± 3.3 minutes.

The slip-knot clip suturing method could close large mucosal defects completely using a single-channel endoscope. (Clinical trial registration number: UMIN000017583.)