Background: Covered, rather than uncovered, metal stents are used for the palliation of dysphagia from esophageal cancer, but a major drawback is the risk of stent migration, which occurs in up to 20% of patients. To overcome this problem, a double-layered stent, the Niti-S stent (Taewong Medical, Seoul, Korea), has been developed. The Niti-S stent consists of an inner polyurethane layer to prevent tumor ingrowth and an outer uncovered nitinol wire tube to allow the mesh of the stent to embed itself in the esophageal wall.
Methods: Between June 2003 and May 2004, 42 patients with malignant dysphagia caused by inoperable carcinoma of the esophagus or gastric cardia were treated with a Niti-S stent. Patients were prospectively followed and data collection focused on recurrent dysphagia, functional outcome, complications, and survival.
Results: At 4 weeks, the dysphagia score had significantly improved from a median of 3 (liquids only) to 0 (ability to eat a normal diet). Five of 42 (12%) patients with a Niti-S stent developed recurrent dysphagia, mainly due to tissue overgrowth (2 of 42; 5%) and stent migration (3 of 42; 7%). Major complications (perforation, 1; aspiration pneumonia, 2; hemorrhage, 2) occurred in 5 of 42 (12%) patients. Pain following stent placement was observed in 5 of 42 (12%) patients, and symptomatic gastroesophageal reflux occurred in 2 of 42 (5%) patients.
Conclusions: The Niti-S stent provides symptomatic relief of malignant dysphagia and effectively reduces recurrent dysphagia. Its double-layered design is probably important in preventing migration. In addition, the complete covering of the Niti-S stent may be a factor in preventing tissue overgrowth at both ends of the stent.