Tracheal stenting currently using non-degradable stents is commonplace for treatment of trauma, prolonged intubation related adult airway obstructions, and pediatric patients-associated tracheal stenosis conditions. Degradable tracheal stent placement will avoid complications of stent removal and restenosis. Widespread reports exist on degradable magnesium alloys success for orthopedic and cardiovascular applications but none to date for intra tracheal use. This research explores the use of pure Mg, AZ31, and Mg-3Y alloys for degradable tracheal stent assessment. In vitro evaluation of magnesium, prototype stents in a bioreactor simulate the airway environment and corrosion. Micro-CT imaging and biocompatibility evaluation helped assess the 24-week degradation of intraluminal alloy stents following implantation in a rat tracheal in vivo bypass model. Histological analysis indicate tissue response of the harvested stented trachea segments after each time point. Corrosion studies for each alloy indicate significant differences between the simulated and control in vitro conditions. AZ31 exhibited the lowest volume loss of 6.8% in saline, while pure Mg displayed the lowest volume loss of 4.6% in simulated airway fluid (SAF), both at 1-week time points. Significant differences in percentage of total volume lost after 6 months were determined between the alloys over time. MgY alloy displayed the slowest corrosion losing only 15.1% volume after 24 weeks of immersion. Additionally, in vitro magnesium alloy corrosion was not significantly different from the percentage of total volume lost in vivo at 1-week time point. The study demonstrates promise of magnesium alloys for intraluminal tracheal stent application albeit viability of a clinically translatable model warrants further studies. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res B Part B: Appl Biomater, 2018.

Rosai-Dorfman disease or sinus histiocytosis is a nonmalignant disease chiefly presenting as a painless cervical lymphadenopathy, although extranodal involvement is also frequent. Involvement of the tracheobronchial tree is extremely rare, and there are no clear guidelines on management. Rosai-Dorfman disease usually presents as a tracheal tumor, although it may also present with extraluminal compression. Only 12 cases have been reported in the English language literature. Histopathology is required to confirm the diagnosis. We describe what we think is India's first reported case of histologically proven tracheal Rosai-Dorfman disease in a 40-year-old otherwise healthy lady.

This paper details the clinical history and management of a 20-year-old male patient who presented with a 2-year history of a neck swelling which was gradually enlarging during the last 3 months. The tumor was histologically diagnosed as an adenomatous nodule of the thyroid gland.

Hyalinizing clear cell carcinomas (HCCC), now referred to as clear cell carcinomas (CCC) by the World Health Organization (WHO), are rare tumors usually arising from the salivary glands of the head and neck. We present the first case of a CCC originating from the trachea. A 66 year-old woman with history of hypertension, former smoker, presented to the emergency department reporting worsening shortness of breath. Computed chest tomography revealed a polypoid mass arising from the left posterior-lateral wall of the trachea. The patient developed worsening respiratory failure requiring mechanical ventilation. Bronchoscopy was completed which relieved a malignant airway obstruction and pathology revealed nests of cells with monomorphic nuclei and clear cytoplasm set in a hyalinized stroma. Using break apart probe fluorescence in situ hybridization testing the tissue revealed the presence of a recurring translocation of the Ewing sarcoma (EWSR1) gene, confirming the diagnosis. CCC is a rare primary airway tumor. CCC was first reported to originate in the lung in 2015. We present the first case of CCC arising from the trachea.

We compared the outcome of Nd:YAG laser therapy with stent placement for malignant central airway obstruction (CAO) at our center over a 10-year period. This is a retrospective review of patients undergoing Nd:YAG laser therapy or self-expanding metal stent (SEMS) placement for malignant CAO between November 2007 and October 2017. Seventy-two patients were recanalized for malignant CAO. The median (range) age was 63 (23-86) years, with 49 (68%) males. Patients underwent either laser therapy alone (N = 36), stent placement alone (N = 30), or both (N = 6). The wavelength of Nd:YAG laser used was 1064 nm, and median (range) laser energy used was 25 (15-35) W, in 377 (115-1107) pulses. Fifty-one (71%) patients died with median survival of 7.2 months. In subgroup analysis, 21 (58.3%) vs. 25 (83.3%), p = 0.03 patients died in the "laser resection" vs. "stent placement" group with longer median survival of 12.4 months in the former vs. 4.5 months, p = 0.0004 in the later. Esophageal cancer and left main bronchus involvement were significantly more common (10 (33.3%) vs. 0, p = 0.0001, and 16 (53.3%) vs. 8 (22.2%), p = 0.01), in the stent placement vs. laser resection group, respectively. Trachea or main bronchi involvement and respiratory failure on presentation requiring mechanical ventilation correlated with poorer survival. The immediate restoration of luminal patency, complication rate, and 30-day mortality was similar among the two groups. The median (range) energy used for laser therapy was 25 (15-35) W. Median of 377 pulses was used for the duration of 287.5 s. The results were compared using a Wilcoxon two-sample test, and Fischer exact test with p values considered indicative of a significant difference if less than 0.05. In patients requiring recanalization of malignant CAO, the extrinsic compression from esophageal cancer, trachea or main bronchi involvement, respiratory failure on presentation requiring mechanical ventilation, and stent placement correlated with poorer survival. Interventional pulmonology training program should emphasize on dedicated training in laser therapy as it is associated with improved survival.

This review presents updated information on small airways in the pathogenesis of chronic obstructive respiratory diseases. The lungs have a branching structure, segmentally divided from trachea down to the alveoli (generations 1 - 23). Airways can be divided into a conducting (generations 1 - 16) and a respiratory zone (generations 17 - 23). Conducting zone is mainly for air transportation, respiratory zone for gas exchange. Increasing attention has been directed to the role of small airways in chronic obstructive respiratory diseases. The small conducting airways < 2 mm in diameter are the major site of airway inflammation and obstruction in COPD. It has been shown that the last generation of small conducting airways, the terminal bronchioles, are significantly destroyed in patients with very severe COPD. At what stage in the development of COPD the loss of small airways occurs is not exactly known. The small airways represent the most important target for deposition of inhaled therapeutic particles. Currently there is no gold standard for detecting small airway dysfunction. Techniques such as spirometry and body plethysmography can provide information on air trapping. High-resolution CT enables the diagnosis of pulmonary emphysema and diseases of the large airways. Only micro-CT imaging offers the option to describe microstructure of terminal bronchioles. Impulse oscillometry, gas washout techniques and analysis of exhaled nitric oxide are diagnostic tools which have to be validated for diagnosis and treatment response of small airway diseases.

Awake fiberoptic nasotracheal intubation is a useful technique, especially in patients with airway obstruction. It must not only provide sufficient anesthesia, but also maintain spontaneous breathing. We introduce a method to achieve this using a small dose of fentanyl and midazolam in combination with topical anesthesia. The cases of 2 patients (1 male, 1 female) who underwent oral maxillofacial surgery are reported. They received 50 µg of fentanyl 2-3 times (total 2.2-2.3 µg/kg) at intervals of approximately 2 min. Oxygen was administered via a mask at 6 L/min, and 0.5 mg of midazolam was administered 1-4 times (total 0.02-0.05 mg/kg) at intervals of approximately 2 min. A tracheal tube was inserted through the nasal cavity after topical anesthesia was applied to the epiglottis, vocal cords, and into the trachea through the fiberscope channel. All patients were successfully intubated. This is a useful and safe method for awake fiberoptic nasotracheal intubation.