Rescue technique for self-expandable metallic stent placement using ultrathin endoscope after failure of the conventional method in patients with malignant colon obstruction: a multicenter retrospective study

Background and aims: Self-expandable metallic stents (SEMS) can be used to treat malignant colorectal obstruction (MCO). Guidewire insertion to the proximal site of MCO is the most important step for SEMS placement. However, some patients cannot undergo guidewire insertion because of total obstruction or location at anatomically challenging areas. We report a guidewire insertion technique using an ultrathin endoscope (UTE) in patients with MCO in whom conventional SEMS insertion failed. Methods: This study was a retrospective cohort study conducted at three academic centers in Korea. The medical records of 956 consecutive patients who underwent SEMS placement during 2012–2021 were analyzed. After failing guidewire insertion using a colonoscope, a UTE was inserted. Guidewire insertion was done through the working channel of the UTE. Following guidewire insertion, the endoscope was removed from the patient. While removing the endoscope, the guidewire was advanced to be located at the originally inserted site. Then, the colonoscope was inserted over the guidewire, and SEMS was replaced. Results: Conventional SEMS insertion failed in 75 patients. Of these, guidewire insertion using a UTE was tried in 59 patients. The rate of technical success was 91.5% (54/59). Considering all patients, the overall technical success rate of SEMS placement was 97.8% (935/956). This technique increased the technical success rate by 5.6% among the total cohort. Conclusions: The UTE facilitated guidewire insertion and enhanced the overall success rate for SEMS placement. In addition, this technique can be used as a rescue method when guidewire insertion fails using a colonoscope.