A viewpoint on material and design considerations for oesophageal stents with extended lifetime

Abstract

Oesophageal stents are meshed tubular implants designed to maintain patency of the oesophageal lumen and attenuate the symptoms of oesophageal cancer. Oesophageal cancers account for one in twenty cancer diagnoses and can lead to dysphasia, malnutrition and the diminishment of patient quality of life (QOL). Self-expanding oesophageal stents are the most common approach to attenuate these symptoms. Recent advances in oncological therapy have enabled patient survival beyond the lifetime of current devices. This introduces new complications for palliation, driving the need for innovation in stent design. This review identifies the factors responsible for stent failure. It explores the challenges of enhancing the longevity of stent therapies and outlines solutions to improving clinical outcomes. Discussions focus on the role of stent materials, construction methods, and coatings upon device performance. We found three key stent enhancement strategies currently used; material surface treatments, anti-migratory modifications, and biodegradable skeletons. Furthermore, radioactive and drug eluting stent designs were identified as emerging novel treatments. In conclusion, the review offers an overview of remaining key challenges in oesophageal stent design and potential solutions. It is clear that further research is needed to improve the clinical outcome of stents and patient QOL.

Stents metálicos autoexpandibles en la obstrucción maligna del esófago: estudio multicéntrico por 25 años

“…Estos resultados demuestran que, si bien la colocación de una se relaciona con el uso creciente de prótesis totalmente cubiertas. Un diseño de stent completamente cubierto aumenta significativamente el riesgo de migración, lo que puede explicarse por la menor adhesión y fijación a la pared esofágica (8) . Por otro lado, este diseño totalmente cubierto es más favorable para prevenir la obstrucción tumoral o el crecimiento hiperplásico excesivo (21) .…”

“…Las características de las endoprótesis esofágicas varían en relación con las propiedades mecánicas, como el material (metal, plástico o biodegradable); las fuerzas radiales y axiales que actúan sobre la luz del esófago, y el tipo y el diseño de la cubierta (parcial, total o descubierta) que rodea la malla de la prótesis (silicona, poliuretano, entre otros). Las implicaciones de las diferentes características de la endoprótesis en los resultados clínicos no se han dilucidado a cabalidad, debido a la falta de resultados de estudios clínicos aleatorios y controlados (8) .…”

Sensors‐based monitoring and treatment approaches for in‐stent restenosis

“…The third‐generation bioresorbable stents have gained popularity in academics 20–22 ; they are different from the metal stents that can be deployed in the body permanently, while the bioabsorbable stents will disappear with the degradation of the stent in the artery 23 . Although the bioabsorbable stent can reduce the possibility of the ISR, it is a long way to reach technology maturity: first, the occurrence of the bioabsorbable stent is late, the first degradable stent was authorized by US Food and Drug Administration in July 2016, 24 the actual therapeutic effects after implanting the bioresorbable stents is questionable; second, small mechanical force and larger structural size of the existing bioresorbable stents make the surgical operations difficult 25 . Moreover, in contemporary clinical practice, a majority of PCIs involve the implantation of a coronary stent, of which 20%–30% is the BMS, and 60%–70% the DES 26 .…”

“…23 Although the bioabsorbable stent can reduce the possibility of the ISR, it is a long way to reach technology maturity: first, the occurrence of the bioabsorbable stent is late, the first degradable stent was authorized by US Food and Drug Administration in July 2016, 24 the actual therapeutic effects after implanting the bioresorbable stents is questionable; second, small mechanical force and larger structural size of the existing bioresorbable stents make the surgical operations difficult. 25 Moreover, in contemporary clinical practice, a majority of PCIs involve the implantation of a coronary stent, of which 20%-30% is the BMS, and 60%-70% the DES. 26 Therefore, it is foreseeable that metal stents will be the mainstream products for clinical applications and surgery for a long time in the future, and the restenosis in the stent it brings cannot be ignored only because of the appearance of degradable stents.…”