A new removable airway stent.
BACKGROUND
Malignant airway obstruction is a feared complication and will most probably occur more frequently in the future because of increasing cancer incidence and increased life expectancy in cancer patients. Minimal invasive treatment using airway stents represents a meaningful and life-saving palliation. We present a new removable airway stent for improved individualised treatment.


METHODS
To our knowledge, the new airway stent is the world's first knitted and uncovered self-expanding metal stent, which can unravel and be completely removed. In an in vivo model using two anaesthetised and spontaneously breathing pigs, we deployed and subsequently removed the stents by unravelling the device. The procedures were executed by flexible bronchoscopy in an acute and a chronic setting - a 'proof-of-principle' study.


RESULTS
The new stent was easily and accurately deployed in the central airways, and it remained fixed in its original position. It was easy to unravel and completely remove from the airways without clinically significant complications. During the presence of the stent in the chronic study, granulation tissue was induced. This tissue disappeared spontaneously with the removal.


CONCLUSIONS
The new removable stent functioned according to its purpose and unravelled easily, and it was completely removed without significant technical or medical complications. Induced granulation tissue disappeared spontaneously. Further studies on animals and humans are needed to define its optimal indications and future use.
Department of Thoracic Medicine, St. Olavs Hospital, Trondheim, Norway.|Faculty of Medicine, Institute of Circulation and Medical Imaging, Norwegian University of Technology and Science (NTNU), Trondheim, Norway; tore.amundsen@ntnu.no.
Tore
T
Amundsen
Department of Thoracic Medicine, St. Olavs Hospital, Trondheim, Norway.|Faculty of Medicine, Institute of Circulation and Medical Imaging, Norwegian University of Technology and Science (NTNU), Trondheim, Norway.
Sveinung
S
Sørhaug
Department of Thoracic Medicine, St. Olavs Hospital, Trondheim, Norway.|Faculty of Medicine, Institute of Circulation and Medical Imaging, Norwegian University of Technology and Science (NTNU), Trondheim, Norway.
Håkon Olav
HO
Leira
Aleris Hospital, Trondheim, Norway.
Stig Sverre
SS
Tyvold
Department of Medical Technology, SINTEF, Trondheim, Norway.|Norwegian National Advisory Unit for Ultrasound and image-guided therapy, St Olavs Hospital, Trondheim, Norway.
Thomas
T
Langø
Department of Radiology, St, Olavs Hospital, Trondheim, Norway.
Tommy
T
Hammer
Faculty of Medicine, Institute of Circulation and Medical Imaging, Norwegian University of Technology and Science (NTNU), Trondheim, Norway.|Department of Radiology, St, Olavs Hospital, Trondheim, Norway.
Frode
F
Manstad-Hulaas
Faculty of Medicine, Institute of Circulation and Medical Imaging, Norwegian University of Technology and Science (NTNU), Trondheim, Norway.|Department of Vascular Surgery, St. Olavs Hospital, Trondheim, Norway.
Erney
E
Mattsson
SEMS; airway stent; interventional bronchoscopy; lung cancer; malignant airway obstruction