nitinol and Airway-Obstruction

Central airway obstruction (CAO) is one of the most challenging, potentially lethal complications in malignant and benign respiratory diseases. Worsening dyspnea is also a relevant cause for reduced quality of life in such patients. Here, we present our data on the application of covered, self-expanding Y-carina nitinol stents due to benign and malignant diseases.. We retrospectively identified 27 patients who had undergone 31 rigid bronchoscopies with implantation of covered Y-carina nitinol stents over a period of 10 years in order to evaluate indication, clinical course, and outcome.. Short-term survival of successfully stented patients with palliative and curative treatment goal did not differ, allowing for diagnosis independent indication. With respect to overall survival, patients with endoluminal obstruction benefited most compared to patients with fistula and/or external compression. Granulation tissue formation (61.3%) and mucus plugging (80.6%) were the most frequent complications. Material defect (6.5%) and migration (3.2%) were rare complications that could be handled by revisional rigid bronchoscopy and stent exchange in some cases.. Implantation of self-expanding covered Y-carina nitinol stents via rigid bronchoscopy is a feasible and safe treatment option for benign and malignant central airway obstruction. Especially in palliative, malignant airway stenosis, stenting might facilitate additional treatment options and optimize dyspnea and eventually quality of life.

Topics: Airway Obstruction; Alloys; Bronchoscopy; Humans; Quality of Life; Retrospective Studies; Stents; Treatment Outcome

A stent is a mesh tube inserted into a natural passage in the body to prevent disease induction. Self-expandable esophageal nitinol stents such as SX-ELLA Stent Esophageal HV (HV Stent Plus) can be indicated for palliation of malignant esophageal strictures, for the treatment of benign esophageal strictures that are refractory to standard therapy and for the treatment of esophago-respiratory fistulas. A silicone-stent coating is used for tumor in-growth prevention and esophago-respiratory fistula occlusion. The thickness of the stent and the overall integrity of the silicone coating of all wires indicate the overall mechanical properties of the esophageal stent and the resistance to external adverse events such as corrosion and mechanical and chemical resistance.. The polymer multicomponent epoxy resin - a mixture of Epon and Durcupan - was used as a method for robust sample stabilization. A cutting system using a thin water beam with a powder (Blue Line) was chosen as the best variant to obtain 6 samples for both-sided measurement (10 measuring sides). The optical microscopic reflective light method was used to examine wire crossing points in the sections. Fifty values were measured on either sample side for the internal, external and mesh thickness of the silicone stent layer. The wire crossing points were selected so that the silicone layer structure could be clearly seen, and the wires approached each other most closely. Only approximately 4 to 8 crossing points in each section could be measured when applying this approach. The resolution of the microscope and calibration (based on the camera used) was 0.677 μm/pixel.. Additional data could be obtained on 8 planes. Two boundary samples were destroyed by the cutting process. Whole coating of the stent was around all mesh wires, especially in areas with higher mechanical stress (wire crossing). The minimum detectable and admissible value determined for all 3 measuring areas (internal, external, mesh) on the wire crossings was 6.77 μm, i.e., 10 pixels, based on the microscope resolution and manufacturer's methodology. The results were characterized by p < 0.001 for all 3 parameters. We tested opposite samples in each section to verify the section quality and data consistency. For the 4 areas, the data were significantly different, but the thickness differences were only on the order of units percent, so the measurements were not appreciably affected. We assume that the material cutting loss, making up 1-2 mm, contributed to the differences in the sections.. We examined the overall integrity of the silicone coating of the esophageal stent. The method of HV stent anchoring in a polymeric bath followed by cutting with a waterjet and sample measurement under an optical microscope proved to be very simple and reliable. Sufficient thicknesses of the silicone layer on the wire cross sections were verified. The coated silicone layer thickness appeared to be significantly different along the stent from the proximal part to the distant part, presumably due to the manufacturing technology.

Topics: Airway Obstruction; Alloys; Constriction, Pathologic; Humans; Silicones; Stents

Tracheobronchomalacia is a rare condition in the pediatric age group which may be life-threatening when it occurs. The common form of tracheomalacia is congenital, presenting with wheezing and cough. We report a case of a 65-day-old baby who was treated with non-invasive mechanical ventilation due to respiratory distress since the day of birth. Tracheomalacia was diagnosed based on the physical examination and the thorax computerized tomography (CT) findings. Patient was initially treated with noninvasive positive pressure ventilation and thereafter, fitted with a tracheobronchial conical fully-covered self-expandable nitinol stent. After stent insertion and the respiratory situation of the patient improved, ventilatory weaning and extubation were possible. A careful selection of suitable patients, appropriate stent type and the site, where it has to be placed is mandatory for successful airway stenting. Also, children must be adequately followed-up to prevent the possible life-threatening complications after stent insertion.

Topics: Airway Obstruction; Alloys; Female; Humans; Infant; Stents; Tomography, X-Ray Computed; Tracheomalacia; Treatment Outcome

Central airway obstruction (CAO) is defined as obstruction of the airway lumen in the trachea or mainstem bronchi, most commonly due to primary or metastatic malignancy; and is classified as extraluminal, endoluminal, or mixed. The majority of malignant CAO are advanced stage and require a multimodality palliative approach, including stent placement. We describe a retrospective review of a novel self-expandable metallic stent, the Bonastent; a fully covered, nitinol-braided airway stent which conforms to airway tortuosity without loss of diameter in the management of CAO.. We performed a retrospective chart review of patients with CAO who underwent Bonastent placement at a single center between February 2017 and March 2018. Ease of stent placement, short-term complications (within 24 h of stent placement) and long-term complications (within 3 mo of stent placement) were recorded.. Eleven patients were identified, reviewed and included in the study. Thirteen stents in 11 patients were placed for predominantly malignant CAO. One patient had a short-term complication of stent migration. Four patients had long-term complications; of which 3 patients had in-stent mucus impaction requiring bronchoscopy. In our study, the stent-related complication rates were comparable to the reported literature.. In our experience, Bonastent is an easy to use option which adds to the armamentarium of the self-expandable metallic stent to treat malignant CAO.

Topics: Adult; Aged; Aged, 80 and over; Airway Obstruction; Alloys; Bronchi; Bronchoscopy; Cohort Studies; Feasibility Studies; Female; Humans; Male; Middle Aged; Mucus; Neoplasms; Palliative Care; Postoperative Complications; Prosthesis Failure; Retrospective Studies; Self Expandable Metallic Stents; Trachea

Topics: Airway Obstruction; Alloys; Bronchial Diseases; Bronchoscopy; Carcinoma, Squamous Cell; Constriction, Pathologic; Humans; Laser Therapy; Lung Neoplasms; Male; Middle Aged; Neoplasm Staging; Predictive Value of Tests; Prosthesis Design; Stents; Tomography, X-Ray Computed; Tracheal Stenosis; Treatment Outcome

Tracheal neoplasms account for less than 1% of all malignancies. In spite of their low incidence, these tumors represent potentially lethal phenomena. In cases of airway compromise and unresectable disease, the airway may be maintained by repeated bronchoscopic debulkings, and the use of CO(2) laser, silicone Montgomery T-tube and tracheal stents. The use of metallic expandable stents to relieve airway obstruction in advanced tracheal tumors was previously reported. Our aim was to evaluate the use of metallic expandable tracheal stents as a palliative relief from severe airway obstruction in cases of locally advanced, inoperable malignant tracheal tumors. Patients suffering from severe airway obstruction secondary to locally advanced tracheal tumors, who presented to the Otolaryngology Head and Neck Surgery and Chest Diseases Departments at the Main Alexandria University Hospital, Egypt, were included in this study. After endoscopic and radiological evaluation, expandable metallic tracheal stents (SENS; Ultraflex tracheal prosthesis; Boston Scientific Corp, Watertown, MA, USA) were inserted under general anesthesia to relieve airway obstruction. Postoperative follow-up with regard to improvement of respiration, tolerability of the stent and reporting of complications was done. Twelve patients were included, eight males and four females with a mean age of 61 years. Four patients (33.3%) had primary tracheal tumors and eight (66.7%) suffered from tumors infiltrating the trachea from nearby structures. The stent was easily inserted in all patients with no significant intraoperative complications. Postoperatively, the stent was well tolerated and all patients experienced good respiration with significant improvement of respiratory function test results. The most common complication reported was granulation tissue formation. Other complications were displacement of the stent, bad breath, re-growth of tumor tissue at the lower end of the stent and retention of secretions. We concluded that Ultraflex self-expandable stent is a good alternative for palliative relief from airway obstruction in cases of inoperable malignant tracheal tumors. Strict follow-up is mandatory for early detection and management of expected complications.

Topics: Adult; Aged; Airway Obstruction; Alloys; Female; Humans; Male; Middle Aged; Palliative Care; Stents; Tracheal Neoplasms; Tracheal Stenosis

The potential role of AERO tracheobronchial covered stents in the management of recurrent postinfectious strictures of the bronchus intermedius was studied in three lung transplant recipients. Six devices were inserted. Five of the stents migrated immediately on placement. Buildup of thick mucus was observed in all stents remaining in the airway for longer than 1 week. Strictures recurred in all patients 1, 3, and 5 months after stent deployment. Attempts at stent retrieval were successful for three of five devices. The use of AERO stents may not offer a therapeutic advantage versus balloon dilation of bronchus intermedius strictures in lung transplant recipients.

Topics: Adult; Aged; Airway Obstruction; Alloys; Bronchial Diseases; Bronchoscopy; Catheterization; Coated Materials, Biocompatible; Constriction, Pathologic; Female; Foreign-Body Migration; Humans; Lung Transplantation; Male; Middle Aged; Polyurethanes; Prosthesis Design; Recurrence; Stents; Time Factors; Treatment Outcome

To assess the efficacy and safety of covered retrievable nitinol stents in oesophageal cancer patients with airway involvement.. Under fluoroscopic guidance, covered retrievable nitinol airway stents were placed in 23 oesophageal cancer patients with airway stricture and/or oesophagorespiratory fistula (ERF) over a long period of 12 years. Six patients only had aspiration by ERF and three patients had both airway stricture and asymptomatic ERF. Technical aspects, dyspnoea improvement, and/or resolution of ERF symptoms, complications, reinterventions, and survival data were evaluated.. A total of 27 airway stents (14 tracheal, 11 bronchial, and two hinged) were placed successfully in 23 patients with airway stricture or ERF. Dyspnoea score decreased significantly after stent placement (p<0.001). ERF were sealed off in all nine patients. Complications included stent migration or expectoration (n=4), haemoptysis (n=2), sputum retention (n=7), and tumour overgrowth (n=1). All three migrated stents were easily removed. Twenty-one patients died, with the median survival period of 76 days (range 2-197 days).. Placement of covered retrievable expandable nitinol stents was safe and effective for the palliative treatment of airway strictures and/or ERF, with a reasonable range of complications, in patients with advanced oesophageal cancer.

Topics: Adult; Aged; Airway Obstruction; Alloys; Bronchi; Bronchography; Device Removal; Epidemiologic Methods; Esophageal Fistula; Esophageal Neoplasms; Female; Fluoroscopy; Foreign-Body Migration; Humans; Male; Middle Aged; Neoplasm Invasiveness; Palliative Care; Radiography, Interventional; Respiratory Tract Fistula; Stents; Tracheal Stenosis; Treatment Outcome

Despite being commercially available for a few years now, the literature regarding the outcome of Ultraflex stent insertion in complex malignant airway stenoses is sparse.. To assess long-term complications and survival in patients with complex malignant airway stenoses treated with insertion of nitinol stents.. 60 consecutive patients with Ultraflex stent insertion for malignant airway stenoses were included. Follow-up was obtained in all patients.. 62 Ultraflex stents (covered = 51, uncovered = 11) were implanted in 60 patients. Diagnoses were bronchial carcinoma (n = 50), esophageal carcinoma (n = 3) and metastases (n = 7). Stents were inserted in the trachea (n = 5), main bronchi/intermediate bronchus (n = 22), from main bronchi/intermediate bronchus to lobar bronchi (n = 28) or in the lobar bronchi themselves (n = 7). Successful reopening of the stenoses and relief were achieved in all patients. There was no procedure-related mortality. Complications included mucous plugging in 8%, stenosing granulation tissue in 5%, tumor ingrowth in 5% and stent migration in 5% of patients. Using Kaplan-Meier estimates, the overall mean survival was 160 days (standard error: 30). Median survival was 91 days. The overall 3- and 6-month survival were 52 and 20%, respectively. Death (n = 59, 98%) was attributed mainly to disease progression with cachexia and metastases, pneumonia (n = 5, 10%), and hemoptysis (n = 1, 2%).. Ultraflex stents have a low complication rate and can be effectively used in complex malignant airway stenoses with marked asymmetry or irregularity, angulation or changing diameters.

Topics: Adult; Aged; Airway Obstruction; Alloys; Bronchial Neoplasms; Carcinoma; Constriction, Pathologic; Female; Humans; Male; Middle Aged; Retrospective Studies; Stents; Survival Analysis

Nitinol alloy stents are in frequent use in recanalizing malignant airway stenoses. Potassium titanyl phosphate (KTP) is one of the lasers of choice in removal of obstructing airway lesions. There is a paucity of research regarding the safety of these advances working together.. In vitro study involving direct contact application of KTP laser with nitinol alloy stents under microscope guidance in varying gaseous environments.. Stent damage can occur once power settings exceed one watt. Complete stent destruction occurs regardless of gaseous environment at a mere three watts of power.. Our results suggest that KTP laser is unsafe to use in the presence of a nitinol alloy stent, regardless of the gaseous environment.

Topics: Airway Obstruction; Alloys; Equipment Failure Analysis; Humans; In Vitro Techniques; Lasers, Solid-State; Stents

Three different internal airway stents were studied in an animal model of tracheomalacia: the Palmaz stent (Johnson & Johnson, Warren, New Jersey) and the NIR stent (Medinol Ltd., Tel Aviv, Israel)--both made of stainless steel in the form of tubular mesh--and the Nitinol stent, made of nickel-titanium formed into a spiral shape. All three stents could be adequately stabilized in the malacic tracheal segment. The Nitinol stent (Medinol Ltd., Tel Aviv, Israel) proved to be less reactive to the tracheal mucosa, demonstrated higher biocompatibility with significantly less granulation tissue formation, and showed superior radial resistance. Extraction of the Nitinol stent also proved to be much smoother. This stent may be the stent of choice in the treatment of tracheo- and bronchomalacia.

Topics: Airway Obstruction; Alloys; Animals; Bronchoscopy; Disease Models, Animal; Prosthesis Design; Stents; Swine; Trachea; Tracheal Diseases; Tracheal Stenosis

Topics: Adult; Aged; Airway Obstruction; Alloys; Bronchi; Female; Humans; Male; Middle Aged; Stents; Trachea

Assessment of the therapeutic potential of tracheobronchial stenting for obstructive tracheobronchial disease, in-vivo comparison of different stent types and development of helpful criteria for choosing the suitable stent type.. Prospective case analysis. Between 1993 and 1999 53 stents were implanted into the tracheobronchial system of 39 consecutive patients with benign or malignant airway obstruction. Every single stent (26 Strecker Stents, 18 Wallstents, 6 Accuflex Nitinolstents, 1 Dumon-, 1 Rüsch- and 1 Palmazstent) was recorded in an unified database. Analysis comprised clinical effectiveness, lung function if possible, relevant complications and radiologic follow-up parameters. The probability of their remaining within the tracheobronchial system, of their remaining undislocated and uncompressed was calculated using Kaplan-Meier analysis for three stent types.. Stent placement proved itself to be an effective treatment in 86 % of the patients. Resistance could be normalized in 9/9 patients. Kaplan-Meier analysis clearly revealed a higher probability for the Wall- and Nitinolstent to remain within the tracheobronchial system and to remain uncompressed. Dislocation also occurred more rarely. Explantation of the Wallstent, however, if desired, was much more difficult compared to the Strecker stent. The Wallstent also occasionally led to the formation of granulation tissue especially at the proximal stent end and, as such, required reintervention.. Any of the 3 stent types proved to be an effective therapeutic option in the management of obstructive tracheobronchial disease. Choise of the stent type should be determined through definition of the therapeutic intention. It is useful to distinguish between (a) benign stenosis, (b) malignant stenosis but curative therapeutic situation and (c) malignant stenosis in a palliative therapeutic situation with limited life expectancy. In spite of its superior mechanical properties the Wallstent is rather suited for a palliative situation because explantation may be difficult. The Strecker Stent requires more reinterventions but removal is easy to perform. The Nitinolstent possibly represents a reasonable compromise.

Topics: Adolescent; Adult; Aged; Airway Obstruction; Alloys; Bronchial Diseases; Bronchoscopy; Child; Child, Preschool; Device Removal; Equipment Failure Analysis; Female; Humans; Infant; Lung Neoplasms; Male; Middle Aged; Otorhinolaryngologic Neoplasms; Palliative Care; Patient Care Team; Prosthesis Design; Radiology, Interventional; Stents; Tomography, X-Ray Computed; Tracheal Stenosis

Topics: Airway Obstruction; Alloys; Bronchial Diseases; Constriction, Pathologic; Foreign-Body Migration; Humans; Stents; Tracheal Stenosis

Recurrent tracheobronchial obstruction whether due to a benign or malignant cause is not always amenable to surgery and one is left with the dilemma of what to do for a patient who is slowly asphyxiating. Various modalities have been employed in the past with varying degrees of success. However due to the recent innovations in 'superelastic' biocompatible alloys we present our clinical experience with a new generation of metallic stents made from Nitinol. Over a 12-month period we inserted eight stents in six patients with malignant and benign tracheobronchial obstruction. Almost all patients had dramatic improvement in their symptoms and there was little airway reaction observed up to 18 months after insertion. However, one should exercise caution in inserting them for benign conditions as we regard them as permanent implants. Also evident is the inherent morbidity in this group of patients and this needs to be carefully considered prior to treatment.

Topics: Adult; Aged; Aged, 80 and over; Airway Obstruction; Alloys; Biocompatible Materials; Bronchial Neoplasms; Female; Humans; Male; Middle Aged; Otorhinolaryngologic Surgical Procedures; Stents; Tracheal Neoplasms; Treatment Outcome

Silicone and metal stents are available for the treatment of malignant bronchial stenoses. This project sought to compare the self-expanding nitinol Accuflex stent (Boston Scientific Corp; Watertown, Mass) with the passively expandable tantalum Strecker stent (Boston Scientific Corp; Watertown, Mass), both implanted by flexible bronchoscopy under local anesthesia and sedation. In 51 patients with malignant bronchial stenosis, 14 nitinol and 51 tantalum stents were used and stenoses of 75 to 100% were treated. The intervention was successful in all but one patient, a mean patency of 93% was achieved. In the follow-up period, the probability of survival was significantly lower in patients with total bronchus occlusion than in patients with stenotic alteration (44 vs 109 days; p < 0.05). In 10 patients, lung function analysis after stent implantation revealed a significant increase in PaO2 (65 vs 71 mm Hg; p < 0.01), inspiratory vital capacity (2.5 vs 2.7 L; p < 0.05), and FEV1 (1.8 vs 2.0 L; p < 0.05). Mucus retention was the main (39%) adverse factor in the early phase after stent implantation, whereas tumor penetration became the most frequent problem (67%) in the later phase. Recanalizing interventions were necessary in 18% of the cases in which tumor penetration occurred. Stent distortion occurred in 12 patients with Strecker and in none with Accuflex stents. In comparison to the Strecker stent, the self-expanding Accuflex stent is preferable owing to its excellent flexibility and faster delivery system. Both types of stents could be sufficiently deployed within the lesions and allowed for highly precise positioning. Furthermore, no general anesthesia was required. The fiber-bronchoscopy mode of implantation under sedation is very efficient even for tumor patients with severe impairment of their physical and respiratory condition.

Topics: Airway Obstruction; Alloys; Bronchial Neoplasms; Bronchoscopes; Equipment Design; Equipment Failure Analysis; Humans; Lung Volume Measurements; Palliative Care; Stents; Tantalum

A polyurethane-covered retrievable expandable stent was placed in 13 patients with tracheobronchial strictures. In four patients with benign strictures, the stent was removed with use of a retrieval hook 2-6 months after placement. After stent removal, three of the four patients did not need further treatment. The retrievable stent warrants further investigation in the treatment of tracheobronchial strictures.

Topics: Adult; Aged; Airway Obstruction; Alloys; Bronchial Diseases; Coated Materials, Biocompatible; Device Removal; Equipment Design; Equipment Failure Analysis; Female; Humans; Male; Middle Aged; Polyurethanes; Stents; Tracheal Stenosis