This is a retrospective, observational cohort study carried out in two operative Units of the University Hospital of Modena (Italy): the Diagnostic and Interventional Bronchoscopy Unit (Unit A) and the Otolaryngology Unit (Unit B). The two units have different protocols routinely applied to treat tracheal benign stenosis. In Unit A, endoscopic treatment is performed through mechanical dilatation via rigid bronchoscopy and further stent placing while in Unit B the endoscopic treatment is performed through balloon dilatation via direct laryngoscopy. The primary purpose was to compare the efficacy of the two technique on tracheal stenosis treatment over time. Patients were defined as "cured" if during the 2 years after 12 months since the last intervention they did not present any of the following: respiratory symptoms, need for a re-intervention or stenosis instability.

Inclusion Criteria:

• age >18 years,
• exclusion from resection-anastomosis surgery after multidisciplinary evaluation,
• Cotton Meyer > grade II,
• follow-up of at least 3 years after endoscopic surgery,
• no previous tracheal surgery.

Exclusion Criteria:

• age > 80,
• stent intolerance which requires removal in the first year after endoscopic treatment,
• performance status > 2,
• end-stage chronic pulmonary disease,
• life-threatening stenosis that needs urgent endoscopic treatments,
• any neoplastic stenosis of the airways,
• dynamic etiology of tracheal benign stenosis (excessive dynamic airway collapse, tracheobronchomalacia).

We collected clinical, endoscopic and radiological data of patients with benign tracheal stenosis admitted in two operative Units of the University Hospital of Modena (Italy): The Diagnostic and Interventional Bronchoscopy Unit (Unit A) and the Otolaryngology Unit (Unit B) from November 2012 to November 2017