Predictors of complications after Montgomery T-Tube insertion in patients with benign tracheal stenosis

Purpose: The primary objective of this study was to identify predictors for unplanned airway interventions after Montgomery T-tube placement in patients with benign tracheal stenosis. Secondary objectives were: to identify predictors of global complications; compare the total complication rate between supraglottic and infraglottic T-tubes and evaluate the total decannulation rate.

Methods: Prospective study which enrolled patients with unresectable tracheal stenosis due to benign diseases. Inclusion criteria included age>18 years, ECOG 0-2, tracheal stenosis with tracheostomy (T-tube insertion), and T-tube replacement. Patients with bronchial stenosis, tuberculosis and other infectious diseases were not included.
Unplanned airway intervention was defined as an unscheduled endoscopic procedure that occurred within 90 days after stent placement. This could be motivated by migration, obstruction/granulation tissue or severe dyspnea. Any clinical/surgical complication occurring within 30 days was considered a postoperative complication. Successful decannulation was defined as removal of the stent without need for further intervention for 6 months. Data was inserted in the REDCap platform and was anonymized.
Variables were tested for the outcomes by univariate analysis(p < 0.1). For the multivariate analysis the alpha error value was 5%. Considering an estimated complication rate of 5%, study power of 80%, it was calculated that 250 procedures were needed for risk predictions.

Results: From July 2018 to July 2022, 153 patients were included (107 male / 46 female) and were submitted to 260 endoscopic procedures. The most common etiology was prolonged intubation (n=132;86%), followed by idiopathic stenosis (n=15;10%). Median intubation period was 15 days (IQR 10-21 days; range 10-90 days). 86% of patients had a tracheostomy upon initial outpatient evaluation. The mean length of tracheal stenosis was 31 (5-90) mm. Complications occurred in 14.2% of procedures (n=37). Unplanned interventions occured in 6.5% of the cases (n=17). T-tube was positioned above the vocal cords in 52 cases (20%). Overall complications are depicted in table 1.
After univariate and multivariate analysis, age>60 years (OR 0.89; 95%CI 0.864-0.920; p< 0.001), BMI>30 (OR 3.73; 95%CI 1.05-13.23; p=0.041) , distance between vocal fold and stenosis ≤ 5mm (OR 7.71; CI95% 2.27-26.23; p=0.001) and distance between vocal fold and stenosis between 6 and 10mm (OR 30.55; CI95% 5.97-156.15; p< 0.001) were predictors for unplanned airway interventions. The T-tube above the vocal cords (transglottic) was the main determinant of overall complications (OR 2.37; 95%CI 1.05-5.34; p=0.037) and unplanned admission to ICU (OR 8.56; 95%CI 1.35-54.12; p=0.022). The decannulation rate at the end of the study was 28%.

Conclusion: T-tube placement is an established treatment for airway stenosis. Overall complications had not been investigated in prospective studies, nor predictors for complications. Age>60 years, BMI>30, distance between vocal fold and stenosis ≤ 5mm, and distance between vocal fold and stenosis between 6 and 10mm were determining factors for the primary outcome of the study . The T-tube positioned above the vocal cords (transglottic) had twice the complications than in the infraglottic position and was the main determinant of global complications and unplanned admission to ICU. Overall complication rate was 14.2% and unplanned interventions occurred in 6.5% of the procedures.

Identify the source of the funding for this research project: none