Removable sinus stent for endoscopic sinus surgery: An animal trial

Background: The goal of endoscopic sinus surgery in chronic sinusitis is to create good drainage of the paranasal sinuses. Metal stents used to prevent lateralization of the middle concha are associated with adverse effects. Objective: The aim of this experimental study was to evaluate the feasibility and safety of a newly developed composite removable stent. Methods: The composite removable stent was implanted in nine sheep (18 stents) in the ethmoid cavity after performing an ethmoidectomy and was examined for stability, ease of removal, and adverse effects. Histologic findings were compared between implantation and nonimplantation sites at several time points after stent deployment and removal. Results: None of the stents migrated or fell out of the nose. After 4 weeks, there was no infection in the nose or around the stents, and there was no damage to the mucosa. An histologic study showed only mild-to-moderate inflammatory cell infiltration relative to control sites, with no damage to the mucosal epithelium and no necrosis at distant sites. At 2 weeks after stent removal, slight-to-moderate fibroplasia was noted in the deep nasal tissue, with slight-to-moderate osteocartilaginous metaplasia and bone remodeling but no necrotic or inflammatory changes in surrounding tissues. At 4 weeks after stent removal, the middle meatus remained open. Conclusion: The promising results of the composite removable stent in a sheep model justify further studies in patients undergoing endoscopic sinus surgery for chromic sinusitis.