Fully covered, retrievable self-expanding metal stents (Niti-S) in palliation of malignant dysphagia: Long-term results of a prospective study

Abstract

Background. In the palliative treatment of malignant dysphagia, fully covered, retrievable metal stents are not commonly used, mainly due to the high risk of migration. Therefore, we performed a prospective study to evaluate the clinical efficacy of a fully covered, retrievable self-expanding metal stent (Niti-S). Method. Between October 1998 and February 2009, 100 consecutive patients with malignant esophageal obstruction treated with the fully covered Niti-S stent (Niti-S, Taewoong Medical, Seoul, South Korea) were included. Data collected contained functional outcome, feasibility of endoscopic stent retrieval, recurrent dysphagia, complications, and survival. Result. At 4 weeks after stent placement, dysphagia significantly improved in all patients (p = 0.000). Recurrent dysphagia occurred in 19 of 100 patients treated with Niti-S stents (19%) mainly due to tumor overgrowth (7/100, 7%), stent migration (6/100, 6%), and food impaction (6/100, 6%). Endoscopic stent retrieval was successful in all the attempted 17 patients (17/100, 17%) – 7 overgrowth, 6 stent migration, 2 stent degradation, and 2 severe pain. Major complications were 2 hemorrhage, 2 severe pain, and 1 tracheal compression (5/100, 5%), and minor complications were 10 retrosternal pain and 7 symptomatic gastroesophageal reflux (17/100, 17%). After a median follow-up of 142 days, 97 patients had expired. There was no stent-related mortality or 30-day mortality. Conclusion. The fully covered, retrievable Niti-S stent has proved its effectiveness for palliation of malignant dysphagia and feasibility of endoscopic retrieval. We estimate its dog-bone shaped flanges at both ends and it being completely covered provide good resistance to migration and overgrowth.