2.3. Stent features and endoscopic technique
We have used BD self-expanding stents (ELLA-CS, Hradec Kralove, Czech
Republic) which were custom-made according to the patient´s airway size
and needs. This stent consists on a polydioxanone monofilament, which is
a semi-crystalline polymer that degrades by random hydrolysis. It has
its own dedicated delivery system which comprises a hollow plastic
guiding tube with an olive at the end. The stent was placed in the
operating room under general anesthesia with complete muscle relaxation.
Stent insertion was performed with rigid bronchoscopy (RB) and
fluoroscopic control. When a concurrent laryngeal lesion was present and
the patient had a tracheostomy, the stent was placed thru the stoma with
fluoroscopic visualization or direct vision guidance with an ultrathin
FB. This procedure proved to be more intricate than the standard RB
technique used in most cases. Bronchography was deemed unnecassary for
stent positioning so we did not use it. When deployed, the stent has
some degree of shape memory and tends to coil achieving its nominal
diameter after a few hours. According to the manufacturer instructions,
this stent maintains full mechanical strength for the first 6–7 weeks
after placement and degrades completely after 14–15 weeks. More
detailed biomechanical and physical properties have been described
elsewhere (6).