Statistical Analysis
The change in the patients performance status pretreatment vs posttreatment for the variables dyspnea, Karnofsky scale, and activity index was analyzed by the paired Students t test. The comparison between the patients with and without adjuvant radiotherapy was made by the Mann-Whitney test for survival and by the Fisher s exact test for the rate of local tumor recurrence leading to reobstruction of the stented airw ay. Significance for all tests w as chosen at the 95 percent confidence level.
Insertion Technique and Position of Stents
A total of 38 silicone stents were inserted in the 31 patients. Two patients received two stents simultaneously; one patient with an esophagotracheal fistula received a tracheal and an esophageal stent (Nottingham) and five patients needed stent replacement because of migration or local tumor recurrence. In 42 percent (13/31) of patients, stent insertion was performed as an emergency procedure because of life-threatening tracheobronchial obstruction. The insertion of all stents proved to be easy and even imperfectly placed stents could be fine-adjusted with a forceps during the procedure. The site of the 38 stents is illustrated in Figure 4. Removal of stents —where necessary —proved to be easy in all cases (n = 5).

Figure 4. Position of 38 stents in 31 patients with inoperable malignant tracheobronchial stenoses.