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Stenting in veterinary medicine has been a rapidly growing method of interventional surgery for several years. This procedure is usually performed in the respiratory and urinary tracts, but there are cases of stenting of blood vessels or gastrointestinal structures. It is based on maintaining the permeability of a given tubular structure, thus allowing the passage of gas or liquid. This procedure is often performed as a first-line treatment in situations where pharmacological agents do not work and as an alternative method, often cheaper than the classically performed ones. There are also cases where stenting is used as a palliative treatment, e.g., to enable defecation in colonic obstruction due to tumour infiltration of the colon wall. Stenting is often a life-saving or comfort-improving procedure for animals, but one should also be aware of possible postoperative complications and be prepared for any adversity. For this reason, this review provides an insight into the current knowledge in veterinary medicine about stenting and the consequences associated with this procedure.

Purpose The literature is devoid of a comprehensive analysis of silicone airway stenting for benign central airway obstruction (BCAO). With the largest series in the literature to date, we aim to demonstrate the safety profile, pattern of re-intervention, and duration of silicone airway stents. Methods An institutional database was used to identify patients with BCAO who underwent rigid bronchoscopy with dilation and silicone stent placement between 2002 and 2015 at Rush University Medical Center. Results During the study period, 243 stents were utilized in 63 patients with BCAO. Pure tracheal stenosis was encountered in 71% (45/63), pure tracheomalacia in 11% (7/63), and a hybrid of both in 17% (11/63). Median freedom from re-intervention was 104 (IQR 167) days. Most common indications for re-intervention include mucus accumulation (60%; 131/220), migration (28%; 62/220), and intubation (8%; 18/220). The most common diameters of stent placed were 12 mm (94/220) and 14 mm (96/220). The most common lengths utilized were 30 mm (60/220) and 40 mm (77/220). Duration was not effected by stent size when placed for discrete stenosis. However, 14 mm stents outperformed 12 mm when tracheomalacia was present (157 vs. 37 days; p  = 0.005). Patients with a hybrid stenosis fared better when longer stents were used (60 mm stents outlasted 40 mm stents 173 vs. 56 days; p  = 0.05). Conclusion Rigid bronchoscopy with silicone airway stenting is a safe and effective option for the management of benign central airway obstruction. Our results highlight several strategies to improve stent duration.

A cervical approach combined with thoracoscopic assistance and preoperative tracheal stenting offers a safe and minimally invasive alternative to sternotomy for managing retrosternal goiters extending to the pericardium with severe airway compression.

Persistent air leak may complicate malignant disease of the thorax, causing significant morbidity and mortality. A 51‐year‐old male with a 30‐pack‐year history of smoking was diagnosed with metastatic esophageal carcinoma with invasion into the right upper lobe of the lung. He developed a large right hydropneumothorax complicated by empyema leading to persistent air leak despite the insertion of two chest drains. Computed Tomography imaging with 3‐dimensional reconstruction showed severe tracheal compression from the enlarging esophageal tumour as well as bronchopleural fistulas in the right upper lobe. Rigid bronchoscopy with metallic tracheal stenting was performed. This was followed by localization and quantification of air leak with an endobronchial collateral ventilation assessment system and a digital chest drain to guide endobronchial valve placement, in a single operative procedure. This novel combination of interventional bronchoscopy techniques enabled successful transition to an ambulatory chest drain and subsequent hospital discharge. We describe a novel technique of simultaneous tracheal stenting followed by localization and quantification of air leak with an endobronchial collateral ventilation assessment system and digital chest drain system to guide endobronchial valve placement in a single operative procedure. This successfully addressed a persistent air leak in a patient with metastatic esophageal carcinoma complicated by invasion into the lung, persistent air leak and empyema, allowing him to be discharged home successfully.

Background It is well known that benign tracheal stenosis represents an obstacle to open surgery, and that its treatment could be challenging. Two endoscopic techniques have so far been adopted to restore tracheal patency: balloon dilatation (BA) through laryngoscopy, and tracheal stenting (ST) with rigid bronchoscopy. The main objective of this study was to compare the efficacy of BA and ST to treat benign tracheal stenosis not eligible for surgery. We also compared the rate of adverse events in the two treatment groups. Methods A retrospective, observational cohort study was carried out at the University Hospital of Modena (Italy) from November 2012 to November 2017 in two separate departments. Patients were considered to be “stabilized” (primary outcome) if they did not report significant respiratory symptoms, or restenosis in the long‐term (2 years) following the endoscopic procedure. Results Sixty‐six patients were included in the study (33 in the BA and 33 in the ST group, respectively). Unadjusted Kaplan–Meier estimates showed a greater therapeutic effect of ST compared to BA at 2 years (hazard ratio = 3.9 95%CI [1.5–9.8], p = .01). After adjusting for confounders, stratified analyses showed that this effect was significant in patients with complex stenosis, idiopathic etiology, and degree of stenosis >70%. Compared with BA, ST showed a higher rate of adverse events (p = .01). Conclusions Compared to BA, ST seems to be more effective in achieving stabilization of tracheal patency in complex benign tracheal stenosis, although burdened with a significantly higher number of adverse effects. These findings warrant future prospective study for confirmation. Level of evidence: 3.

A 2.7 kg, 11-year-old, castrated male Maltese dog was presented for evaluation of a 2-year history of intractable coughing, dyspnoea and cyanosis. A diagnosis of tracheal collapse with myxomatous mitral valve disease was made on the basis of inspiratory and expiratory thoracic radiographs, fluoroscopy and echocardiography. Measurement for stent size selection was performed on thoracic radiographs. A 10 mm (diameter) × 70 mm (length) self-expanding double-wire woven uncovered nitinol stent was used for intratracheal implantation and was deployed under fluoroscopic guidance. On thoracic radiography seven days after surgery, the position of the stent remained unchanged. On presentation six months after surgery, the owner reported that the dog was doing well without medical management. Although studies of various intraluminal stents have been reported in dogs, to the authors’ knowledge, use of a double-wire woven uncovered nitinol stent has not been reported previously for the management of a dog with tracheal collapse. Since this particular type of stent with unfixed individual cells provided proper airway patency without stent fracture in the dog in this report, this stent might be used as an alternative to other commercially available nitinol stents in cases of thoracic inlet collapse.

Endoluminal dilatation and stenting is an alternative management strategy in patients with tracheal stenosis. Providing anaesthesia and maintaining oxygenation during tracheal stenting can be difficult. There are various anaesthetic techniques available for this procedure, based on the characteristics of stenosis and anaesthesiologist experience. A good knowledge about the procedure and communication with the radiologist are essential for the safe conduct of anaesthesia. In patients with near total obstruction and respiratory insufficiency, airway manipulation or coughing can result in complete loss of the airway. Herewith we report the anesthetic management of two cases with tracheal stenosis for stenting.

We experienced an unacceptably high 21% complication rate with the stainless steel Gianturco stent: a 68-month mean follow-up (range: 37-96 months) of 23 patients revealed three stent fractures and two migrations. Consequently, we began using nitinol mesh stents (Ultraflex) for fibrous stenoses and silicone-covered prostheses (Rush) for proliferative tracheal tumors. The extractable nitinol stent, made from alloy with thermal memory, was palliatively used in 15 patients with fibrous tracheal stenosis; the mean follow-up currently covers 21 months (range: 1-60 months). The silicone-covered prosthesis was used for two patients with inoperable tracheal tumor; follow-up covers 4 months and 2 months, respectively. The prostheses were positioned under visual guidance via the endoscopic approach. The median forced inspiratory volume in 1 s (FIV1) improved from 2.1 l/s (IQR: 0.7-2.4) to 3.2 l/s (IQR: 0.9-3.4) (P=0.018, Wilcoxon signed rank test). The median ratio of peak inspiratory flow (PIF 50%) to peak expiratory flow (PEF 50%) was 1.0 preoperatively (IQR: 0.8-1.5) and 1.8 postoperatively (IQR: 0.6-6.3). Between months 1 and 12, six granulomas developed. Five were treated with antibiotics and steroid aerosol inhalation therapy and one required CO2 laser vaporization. On day 10, one stent migration was observed. The migrated stent was substituted. To date, no stent fracture has been observed. Nitinol and silicone-covered prostheses can be proposed for the palliative treatment of fibrous tracheal stenoses and tracheal tumors, respectively.

Six patients known to have inoperable esophageal carcinoma presented with stridor due to both malignant tracheal stenosis (with additional respiratory-digestive tract fistula in 2 patients) and bilateral vocal cord paralysis. Patency was restored by endotracheal stenting plus unilateral cordotomy. Four patients had immediate relief. Two patients required enlargement of the vocal cord incision. One of them declined reoperation and underwent tracheostomy. The stent function was uneventful, with no dislodgment or mucus impaction. The fistula seal was complete, with no aspiration through the newly shaped glottic orifice. The peak expiratory flow increased from 24.4% ± 9.7% of predicted normal before the procedure to 40.5% ± 13.7% after the procedure. Restoration of airway continuity in serial laryngotracheal stenoses by a combined approach is a feasible technique in end-stage cancer patients. It effectively relieves respiratory distress and ensures voice preservation. In addition, it may avoid the risks of tracheotomy.

This chapter discusses the background, potential risks, complications, expected outcomes, equipment, fluoroscopic procedure, special considerations, and the complication examples for intraluminal tracheal stenting. Intraluminal stenting is a palliative, minimally invasive therapy used for restoration of an obstructed or narrowed tracheal lumen. While the most common indication is for treatment of intractable dyspnea, honking/raspy breathing, and/or possible coughing associated with the tracheal collapse syndrome, stenting can also be performed in animals with obstructions secondary to strictures or tumors in both dogs and cats. When stenting for tracheal malformations, incomplete tracheal wall apposition by the stent is one of the most common complications encountered. Tracheoscopy performed prior to and following stent placement can help identify these cases and ensure there is good wall apposition; if not, the endotracheal tube cuff can be used to gently expand the stent to improve wall apposition.