A Review of Recent Patents on Structures Related to Tracheal Stents

Background: The trachea is an important part of the respiratory system. Long-term airway diseases and the effects of human physiological conditions can cause trachea stenosis. This will seriously affect patients’ physical health. Tracheal stents can provide durable support by means of dilating the narrowed area; they can effectively relieve the patient's breathing difficulties, which is of value that is more practical. Objective: To meet the vital requirements for better adaptation to the human airway environment and prevent complications associated with stent placement, the construction and materials of tracheal stents have been improved constantly. Methods: This paper investigates various representative patents related to the tracheal stent. The structure type, placement method and applications situation of these tracheal stents are discussed. Results: The characteristics of different types of tracheal stents are analyzed. This paper analyzes the main problems in its development. The solutions to the issues and the current and future research on tracheal stents are discussed. Conclusion: The tracheal stents are classified into metal stent, silicone stent, biodegradable stent and hybrid material stent. Further improvements are needed in the aspects of structural design, safety, applicability, biocompatibility, algorithm of drive model of tracheal stent. More related patents about tracheal stents need to be developed.

Radiation-Related Hypopharynx-Stenosis with Spared Larynx Treated by a Novel-Shaped Silicone Stent

Background: Radiation-related hypopharyngeal stenoses are considered as complications after larynx sparing therapy of hypopharyngeal or laryngeal tumors. Methods: The reported patient suffered from chondronecrosis of the cricoid after radiation of a larynx carcinoma and was treated by removing the necrotic cartilage. To prevent emerging stenosis of the hypopharynx, a customized hypopharyngeal stent was constructed on the basis of CT scan data. The Y-shaped stent was placed dorsal to the larynx, caudal to the arytenoid cartilages and remained in place without dislocation or irritation of the larynx for 8 weeks. During that time, the hypopharynx was stented, and the mucosa grew around the stent covering the complete circumference of the hypopharynx again. 18 weeks after removal of the stent, the hypopharynx did not reveal any re-stenosis. Conclusion: This customized hypopharyngeal stent is the first reported approach applied with spared larynx, which has been tolerated for a long period of time.

Effect of Silver Nitrate Application on the Success of Endoscopic Dacryocystorhinostomy

Objectives To compare the clinical outcomes of patients undergoing additional procedures in endoscopic endonasal dacryocystorhinostomy (End-DCR) surgery and discuss the factors affecting the success of End-DCR surgery in light of relevant literature. Methods The study included 155 patients who underwent End-DCR surgery in our clinic due to epiphora. This was a prospective randomized, single-blind, controlled trial. Group I (control) included 54 patients who did not undergo silicone stent insertion or silver nitrate application, group II included 51 patients who underwent silicone stent insertion only, and group III included 50 patients who underwent silver nitrate application only. Statistical analysis was performed on follow-up data regarding anatomic and functional success rates. Results Revision surgery was performed in 16 patients who developed persistent epiphora in the postoperative period, including 6 in group I, 7 in group II, and 3 in group III ( P = .4). The most common reason for revision surgery was stenosis of the neo-ostium ( n = 8), followed by granulation tissue formation ( n = 5) and synechia formation ( n = 3). Granuloma formation was the most common postoperative complication, and a significant difference was found among the groups with regard to granuloma formation ( P = .04). At postoperative month 12, the functional success rate was estimated to be 88%, 86%, and 94%, and the anatomic success rate was estimated to be 94%, 92%, and 96% in groups I, II, and III, respectively, with no significant difference, found among the 3 groups with regard to both rates ( P = .79 and P = .76, respectively). Conclusion The results indicated that stenting and silver nitrate application did not affect surgical success. Our preliminary results on silver nitrate cauterization showed that it is an effective, inexpensive, and practical method to reduce granulation formation in the postoperative period.

A Parametric Tool for Studying a New Tracheobronchial Silicone Stent Prototype: Toward a Customized 3D Printable Prosthesis

The management of complex airway disorders is challenging, as the airway stent placement usually results in several complications. Tissue reaction to the foreign body, poor mechanical properties and inadequate fit of the stent in the airway are some of the reported problems. For this reason, the design of customized biomedical devices to improve the accuracy of the clinical results has recently gained interest. The aim of the present study is to introduce a parametric tool for the design of a new tracheo-bronchial stent that could be capable of improving some of the performances of the commercial devices. The proposed methodology is based on the computer aided design software and on the finite element modeling. The computational results are validated by a parallel experimental work that includes the production of selected stent configurations using the 3D printing technology and their compressive test.

Evaluation of the Efficacy of Postoperative Triamcinolone in Endoscopic Dacryocystorhinostomy using Lacrimal Symptom Questionnaire

Purpose: To evaluate the effect of postoperative nasal triamcinolone spray use in primary endoscopic dacryocystorhinostomy using The Lacrimal Symptom Questionnaire .Methods: This study included a series of 50 consecutive retrospective cases with primary endoscopic dacryocystorhinostomy and with silicone stent implantation who were followed up for 6 months postoperatively. Patients using nasal triamcinolone spray for 3 months postoperatively were included in the triamcinolone group. Patients not using triamcinolone were included in the control group. Lacrimal stents were removed 3 months postoperatively. The Lacrimal Symptom Questionnaire (Lac-Q) was performed in the preoperative and postoperative 6th month. Anatomical success, functional success, and changes in lacrimal symptom and social impact scores were compared between the two groups 6 months after surgery.Results: Results of 48 endoscopic dacryocystorhinostomies performed on 48 patients (23 triamcinolone group, 25 control group) meeting the inclusion criteria were analyzed. The anatomical success rate (95.7% vs. 84.0%, p = 0.350) and the functional success rate (91.3% vs. 76.0%, p = 0.249) were higher in the triamcinolone group, but this difference was not statistically significant. No complications were observed in the triamcinolone group, whereas complications developed in two patients in the control group (p = 0.490). The mean change in total lac-Q score was 11.0 in the triamcinolone group and 9.0 in the control group (p = 0.011). The mean change in social impact score was 4.0 in the triamcinolone group and 3.0 in the control group (p = 0.005). Mean change in lacrimal symptom score was 6.0 in the triamcinolone group and 6.0 in the control group (p =0.368)Conclusions: Our study indicated that postoperative use of triamcinolone spray increases the success rate of endoscopic dacryocystorhinostomy. also revealed that triamcinolone may also lead to greater improvement in quality of life scores than the control group using a validated questionnaire.

Balloon Dacryocystoplasty with Pushed Monocanalicular Intubation as a Primary Management for Primary Acquired Nasolacrimal Duct Obstruction

Though dacryocystorhinostomy (DCR) has long served as the gold treatment for primary nasolacrimal duct obstruction (PANDO), balloon dacryocystoplasty (DCP) and silicone stent intubation were applied especially in partial PANDO in the attempts to avoid osteotomy and reduce invasiveness. Herein, we present the results of the combined procedures with balloon DCP and pushed monocanalicular intubation in complete PANDO, and comparison of the combination to balloon DCP alone. We retrospectively reviewed 72 eyes of 56 patients, including 37 eyes of 29 patients in the combination group and 35 eyes of 28 patients in the balloon DCP alone group. There was no significant difference in the success rate between antegrade balloon DCP with and without pushed MCI in general. Nevertheless, interestingly the former procedure was associated with significantly higher surgical success rate than the latter in younger patients.

Postoperative bronchopleurale Fisteln: Modifizierte Stents als maßgeschneiderte interventionelle Therapieoption

<b>Background:</b> Bronchopleural fistula is a rare but life-threatening event with limited therapeutic options. We aimed to investigate the efficacy and safety of the modified silicone stent in patients with post-surgical bronchopleural fistula. <b>Methods:</b> Between March 2016 and April 2020, we retrospectively reviewed the records of 17 patients with bronchopleural fistula and who underwent bronchoscopic placement of the Y-shaped silicone stent. The rate of initial success, clinical success and clinical cure, and complications were analyzed. <b>Results:</b> Stent placement was successful in 16 patients in the first attempt (initial success rate: 94.1%). The median follow-up time was 107 (range, 5–431) days. All patients achieved amelioration of respiratory symptoms. The clinical success rate was 76.5%. Of the 14 patients with empyema, the daily drainage was progressively decreased in 11 patients, and empyema completely disappeared in six patients. Seven stents were removed during follow-up: four (26.7%) for the cure of fistula, two for severe proliferation of granulomatous tissue and one for stent dislocation. No severe adverse events (i.e. massive hemoptysis, suture dehiscence) took place. Seven patients died (due to progression of malignancy, uncontrolled infection, myocardial infarction and left heart failure). <b>Conclusions:</b> The modified silicone stent may be an effective and safe option for patients with post-surgical bronchopleural fistula patients in whom conventional therapy is contraindicated.