Development and Evolution of a Viable Stent Device (PulmoStent) for the Treatment of Broncho-Tracheal Cancer
Airway stenosis is a key problem in the palliative treatment of bronchial and tracheal cancer associated with significant morbidity and premature death. To adequately maintain an acceptable quality of life and reduce the number of hospitalizations in these cancer patients, stenosis has to be treated to avoid severe complications. Stenting is nowadays a proven therapy and can help to keep the airways open. However, current stents have major disadvantages leading to early failure either by rapid re-occlusion due to tumor ingrowth (metal stents) or massive mucus retention due to the interrupted mucociliary function (coated stents).
The aim of the EU-project PulmoStent is the development of a viable endobronchial stent for the treatment of broncho-tracheal cancer diseases. This novel metal stent allows on the one hand a re-epithelialization and on the other hand avoids the re-stenosis of the airways. Figure 1 shows a schematic illustration of such a stent. The scaffold is set up by a self-expanding Nitinol stent which is coated with a separating layer of polyurethane (PU). With the help of an adhesion layer the tissue-engineered functional respiratory epithelium, which allows the maintenance of the mucociliary function, is coated on the inner side of the stent.
Within the framework of this project, the CVE deals with the development of the PU-layer. To meet the requirements, this separating layer has to prevent the ingrowth of tumor cells into the stent and at the same time ensure the transport of nutrients to the epithelia cells on the luminal side of the stent. Therefore, PU fleece material is manufactured by means of spray atomization. The resulting fleece properties like for example the fiber thickness, fiber density and fleece thickness are trigged via different process parameters.
The PulmoStent is a step beyond the state-of-the-art, evolving from a passive to a viable, functional and active implant tailored to the patient. It focuses on a clearly identified clinical need for the treatment of lung cancer. The combination of different biomaterials to a co-scaffold system for the bio-functionalization of the stent will lead to an improved performance of endobronchial stents and thereby to longer durability. The novel PulmoStent might improve the quality of life and increase the life expectancy of lung cancer patients because of the local tumor suppression, the reduced mucus retention in the stented area and herewith the reduced risk of life-threatening pneumonia.