A novel puzzle ring replacement technique of a lumen-apposing metal stent with a double-pigtail plastic stent to prevent walled-off necrosis recurrence (with video)

Replacing a lumen-apposing metal stent (LAMS) with a double-pigtail plastic stent (DPS) after treatment for walled-off necrosis contributes to the prevention of recurrence. However, the success rate is not very high. To overcome this issue, we devised a novel stent-replacement technique. In the final treatment procedure, a 7-F DPS was placed in the lumen of the LAMS. Subsequently, the walled-off necrosis shrank, and granulation formed over the pigtail portion, which fixed the DPS. The LAMS alone was removed with grasping forceps, leaving the DPS in the lumen of the LAMS (i.e., a puzzle-ring technique; direct or rotary removal technique). Between August 2021 and August 2023, 18 patients were evaluated for recurrence prevention using this novel technique (median duration of LAMS placement, 37 days). In 17 patients (94.4%), the LAMS was successfully replaced with a 7-F DPS (direct technique 14, rotary technique 3; median removal procedure time, 3 min). No recurrence was observed during the median observation period of 385 days. Before using this technique (April 2012 to August 2022), the technical success rate of replacement of LAMS with 7-F DPS was significantly lower (61.8% [42/68, p = 0.02]). Recurrence of pancreatic fluid collection occurred in 15.3% (4/26) of the patients who could not undergo replacement with a 7-F DPS. The novel puzzle ring technique, which improves the success rate of LAMS for DPS replacement, may be useful in reducing recurrence after walled-off necrosis treatment.