New tracheal stainless steel stent pilot study: twelve month follow-up in a rabbit model

Abstract

Background Canine tracheal collapse is a complex airway pathology without promising treatment results. Currently nitinol stents are the best surgical option; however, some professionals are doubting if stent placement is the best option due to the associated complications. Objective Determine the technical feasibility, safety, and long-term follow-up after the implantation of a new tracheal stent designed for canine tracheal collapse. Methods Thirteen healthy, adult female New Zealander rabbits were involved in this pilot study.A new intra-tracheal device (Reference number 902711 patent registered as CasMin-Twine) was implanted in ten animals. Deployment was performed under general anesthesia, making a puncture incision via a 21 Gauge needle in the intra-tracheal space where the stent was introduced with a screwing process. The device was fixed to the tracheal wall with a non-absorbable suture. Computerized Tomography (CT) and an endoscopy to study structural abnormalities were performed after 30, 90 and 365 days after stent placement. Results Technical and clinical success was 100%. There was no significant change in behavior or respiratory disorders. CT studies showed no significant alterations. After the 30 days, 60% of the animals showed partial endothelization in the endoscopy study, and only one animal still presented partial endothelization after 12 months. Mucus accumulation was only present in 40% of cases and classified as low, without respiratory consequences. Only one animal presented a single granuloma at caudal stent tip. Conclusions This new tracheal stent (CasMin-Twine) is an effective and safe procedure with promising results, and also shows the possibility of removing the device after endothelization has been produced. New studies should be carried out to evaluate the effectiveness in patients with tracheomalacia. Clinical Significance/Impact This new product can give veterinarians a new option of treatment for this complicated pathology. Minimizing specific equipment for its deployment, CasMin-Twine will be more accessible for all professionals.

Stents in Veterinary Medicine

“…Another equally important property is its biocompatibility with surrounding tissues, which prevents inflammatory reactions and responses [ 24 ]. Other metals are not as common as nitinol, however, the use of materials such as stainless steel or elgiloy, which has very similar properties, has been reported [ 27 , 28 ].…”

State of the Science in Tracheal Stents: A Scoping Review

“…Twenty-eight studies employed bare metallic stents, grouped into four distinct types: steel, [10][11][12][13][14][15][16][17][18][19] nitinol (Ni-Ti alloy), 4,12,13,[19][20][21][22][23][24][25][26][27][28][29] magnesium alloys, [30][31][32][33] and elgiloy (Co-Cr-Ni alloy) 23,34 as outlined in portions of Tables I-III. Only two studies failed to identify the metal used in the employed tracheal stent.…”

“…Only two studies failed to identify the metal used in the employed tracheal stent. 35,36 Of the studies on bare-metal stents, eight were in humans, 4,[10][11][12][13][34][35][36] four in swine, 15,17,19,26 seven in rabbits, 14,16,25,29,[31][32][33] five in canines, [20][21][22][23][24] one in sheep, 18 one in felines, 28 and one in rats. 30 Nitinol, steel, and elgiloy stents were used in human as well as pre-clinical studies, while magnesium alloy stents were trialed only in animal models to determine feasibility and biocompatibility.…”

A new airway spiral stent designed to maintain airway architecture with an atraumatic removal after full epithelization—Research of feasibility and viability in canine patients with tracheomalacia

“…Each stent has pros and cons, but complications are always present. 33,34 The "ideal airway stent" should allow a perfect mucous flow, reduce foreign body reaction, and give enough support to maintain permeability of trachea and main bronchus. In pediatric patients, the device must allow an atraumatic placement as well as the exchange.…”

“…10,38 In this study, the spiral design allowed us to introduce it with precision in a small airway without any complications, and it was possible to reposition the SS anytime, as observed in another study with the same stent shape. 34,35 The new surgical approach has the drawback of being an open surgery, but screwing or unscrewing the SS enables to change the position until the precise situation is achieved. Furthermore, as with classic stents, we observed an early epithelization, but without signs of hyperinflammation or mucous accumulation.…”