Objective To improve the knowledge on dynamic benign central airway stenosis through two typical cases. Methods The clinical features, imaging findings, and bronchial morphologic changes of two cases characterized by dynamic benign central airway stenosis were retrospectively analyzed. The etiologies for the two cases were tracheobronchomalacia (TBM) and excessive dynamic airway collapse (EDAC), respectively. Results Central airway stenosis and reversible airway obstruction were common clinical characteristics for the two cases. However, there were identifiable differences on imaging findings and bronchial morphologic changes between the two cases. Multidetector computed tomography showed sabre-sheath trachea and narrowed trachea in coronal position for TBM, while small sized trachea in exhalation phase and narrowed trachea in sagittal position for EDAC. Bronchoscopy displayed narrowed airway, swelling mucosa, and the absence of annular cartilage for TBM, while crescent airway with membranacea part protruding to lumen in inspiration phase, and the integrity of annular cartilage for EDAC. Conclusion Multidetector computed tomography and bronchoscopy examinations are valid methods to distinguish TBM and EDAC, which are both characterized by dynamic benign central airway stenosis.
ObjectiveTo establish a model of tracheomalacia in beagle dogs.MethodsSix healthy male beagles were selected with a weight of 12-15 kg and age of 12-18 months. The dog was placed in supine position after being anesthetized. Then midline incision was performed on dogs' cervical skin and main trachea was dissected. Six continuous cartilage rings separated from the tracheal wall were removed. Finally, the endotracheal mucosal was examined and the wound was sutured layer by layer. Different degrees of cartilage were removed to simulate different degrees of tracheomalacia. The beagle dogs were classified into two groups (n=3 in each group): a mild tracheomalacia (MTM) group (part of the cartilage near the trachea membrane was retained) and a severe tracheomalacia (STM) group (cartilage was removed as much as possible).ResultsThe dogs in the MTM group survived for a long time after the operation, showing symptoms of airway stenosis such as wheezing and coughing. The dogs were killed at postoperative week 2, and the pathological examination was performed. In the STM group, severe asphyxia occurred in the experimental animals after tracheal intubation removed, and all dogs died within 1 hour after surgery. Postoperative bronchoscopy revealed that the trachea of the MTM group dogs collapsed in the phase of inhalation, but it could maintain a certain patency. The trachea of the STM group dogs collapsed completely in the phase of inhalation. Postoperative X-ray showed that the diameter of the airway in the MTM group was reduced and trachea did not completely collapse. In the STM group, the trachea collapsed completely at the cartilage removed segment. Pathological examination showed that the cartilage in the MTM group was partially removed and tracheomalacia was obvious in the cartilage removed segment. In the STM group, most of the cartilage was removed with only few cartilages left.ConclusionThe clinical symptoms of tracheomalacia in different degrees can be simulated and repeatable. Animal models can be established by controlling the degree of removal of tracheal cartilage ring in dogs. This method provides a simple, repeatable and standardized large animal model for the treatment and transformation of tracheomalacia.