Hybrid Knife, a Novel Drug Delivery Tool for Treatment of Tracheal Stenosis: A Case Report

The treatment of subglottic stenosis remains a challenge due to anatomic and technological limitations, and there is no consensus regarding treatment. Restenosis and granulation formation are the most common complications. Balloon dilatation combined with cryotherapy and adjuvant topical medication is one treatment method. However, the efficacy of adjuvant topical medication is controversial, and the lack of efficacy may be related to the effective dose of the drug delivered to the submucosal layer of the lesion. Therefore, a tool with high efficiency for delivering medications to the submucosal layer via injection may play an important role in treatment. A hybrid knife (HK) with a pressure water jet traditionally used in endoscopy submucosal dissection to inject saline into the submucosa was employed here to inject medications for subglottic stenosis, followed by electrical excision. Here, we report the case of a man with complex subglottic stenosis who underwent balloon dilatation combined with cryotherapy and an adjuvant submucosal triamcinolone injection performed with an HK. The drug was delivered more efficiently into the submucosal layer, and the lumen of the trachea was patent. Performing a submucosal injection with an HK may be a new approach to deliver medications to the submucosal layer for the treatment of tracheal stenosis.