Tracheal stricture and fistula: management with a barbed silicone-covered retrievable expandable nitinol stent

Beware of spurious tracheo-bronchial stents

OBJECTIVE

To present a case of accidental sheath removal of tracheo-bronchial self-expandable metallic airway stent in a patient with endotracheal tumour.

METHODS

Design: Case Report; Setting: Tertiary care hospital; Patient: One.

RESULTS

A 65 years male, follow up case of endotracheal tumor with tracheo-bronchial self-expandable metallic stenting done presented with dry cough and difficulty in breathing since 8-10 days and suddenly coughed out thin whitish paper-like material 2 days back (which later proved as sheath of metallic stent). Direct laryngoscopy with flexible videobronchoscopy was done which showed tracheal stent well placed and intact, coughed out sheath couldn't be replaced back. Procedure was uneventful and patient was discharged in satisfactory condition and is doing well on regular follow up.

CONCLUSION

Self-expandable metallic airway stents (SEMAS) represents a standard method of airways stenting especially when employed for the management of malignant central airway obstruction. Despite the obvious stenting advantages, it may be complicated with stent migration and accidental removal or coughing out of stent especially in high tracheal stenosis. In our case, as a peculiar complication there was accidental removal of the tracheal stent sheath which couldn't be replaced back whereas stent was well in place and intact. We need to be beware of such spurious tracheo-bronchial stents.

Treatment of aerodigestive fistulas with a novel covered metallic Y-shaped segmented airway stent customized with the assistance of 3D printing

Background

The management of aerodigestive fistula remains challenging. An airway stent that matches well with the individual geometry of the airway is needed for the treatment of the aerodigestive fistula. This study aimed to evaluate the feasibility of a novel covered metallic segmented Y-shaped airway stent customized with the assistance of 3D printing in aerodigestive fistulas involving the carina and distal bronchi and to compare the flexibility of the novel stent with the conventional wholly knitted stent.

Methods

In the flexibility study, we measured the longitudinal bending force and spring-back force of the segmented stent and wholly knitted stent. Patient-specific stents that were individually customized with the assistance of 3D printing technology were implanted in 26 patients with aerodigestive fistulas. The technical success, clinical success, Karnofsky performance status (KPS), and stent-related complications were recorded.

Results

The bending force and spring-back force of the segmented stent were significantly lower than those of the wholly knitted stent. Stent deployment was technically successful in all patients. Clinical success was obtained in 21 patients. The KPS of patients after the stenting procedure improved significantly compared with that before stenting (P<0.001). During follow-up, granulation tissue proliferation, sputum retention, stent migration, and intolerance of the stent were found in 2, 5, 1, and 1 patient, respectively.

Conclusions

The segmented metallic Y-shaped airway stent had greater flexibility than the wholly knitted stent in an ex vivo setting. Implantation of the segmented stent individually customized with the aid of 3D printing is feasible in treating aerodigestive fistulas involving the carina and bronchi distal to the carina.

Internal fixation of the proximal tracheal self-expandable metallic stent (SEMS): migration prevention in high risk patients

Airway stenting provides an important treatment option for patients with proximal tracheal stenosis. However, the risk of migration remains a major challenging problem. In our report we describe the internal fixation of SEMS in 3 patients with proximal tracheal stenosis due to variable causes. The fixation was performed in different situations including: prophylaxis to prevent the stent migration, fixation due to displacement of the stent during insertion and finally internal fixation of migrated tracheal stent.

Design and Biomechanical Analysis of a Novel Retrievable Peripheral Vascular Stent

Structurally retrievable drug-eluting stents may have valuable clinical applications because they do not leave any foreign materials inside the patient's body. This article presents a novel design of retrievable peripheral vascular stent and the results from biomechanical analysis of its performance. Using the finite element analysis method, principal parameters of the stent were studied. Moreover, to ensure the practicability of the retrieval process, simulation, and in vitro experiments were performed. The retrieval force reached the maximum value when the whole retrievable part had been retrieved. Furthermore, the force was gradually increased during the retrieval process and remained constant after the main part had been retrieved. When the stent was being compressed, the maximum strain of the stent occurred at the connection between the stent's retrieval part and the main body part, at a value of 4%. The index of nonuniformity of the stent was too small to be counted both at the end of the compression and self-expansion processes. With the increase of moment, the bending stiffness (EI) of the stent decreased gradually. After bending moment was applied, the large strain region was mainly located in the stent's main body part rather than the retrieval part. The results of preliminary stent retrieval experiments demonstrated that the stent could be retrieved successfully. This novel retrievable stent displays promising biomechanical performance. The preliminary experiments demonstrated that the stent could be retrieved smoothly from the blood vessels.

Retrievable covered metallic segmented Y airway stent for gastrorespiratory fistula of carina or main bronchi

OBJECTIVE

To evaluate the feasibility of new retrievable covered metallic segmented Y airway stents modified with 3-dimensional (3D) printing for gastrorespiratory fistula involving carina or main bronchi.

METHODS

We designed a new retrievable covered metallic segmented Y airway stent to fit the anatomical characteristics of the carina region in individual patients. All stents were individually customized based on a 3D-printed mold. Six patients with gastrorespiratory fistula and aspiration pneumonia after esophagectomy underwent the stent implantation. The stents were retrieved when the fistula was cured or stent-related complications occurred.

RESULTS

Seven Y stents were successfully implanted and removed in 6 patients. All stents expanded well, and the fistulas were completely sealed. Aspiration pneumonia was controlled in 6 patients. The median Karnofsky Performance Status scores significantly improved after stenting compared with those before stent implantation (P = .024). Sputum retention was the most common complication after stenting and was treated with aspiration under bronchoscopy (33.33%). Excessive granulation tissue proliferation was found in 1 patient (16.7%) and was treated with cryotherapy. The indwelling time of the stent was 64 days (interquartile range, 52-69 days). After stent removal, bronchoscopy, gastroscopy, and computed tomography of the chest showed cured fistulas in all patients, and no stents showed fractures.

CONCLUSIONS

Retrievable covered metallic segmented Y airway stents modified with 3D printing appear to be feasible for the treatment of gastrorespiratory fistula involving carina or main bronchi.

Recent advancements in the minimally invasive management of esophageal perforation, leaks, and fistulae

INTRODUCTION

Historically, the gold standard management of esophageal perforations, leaks, and fistulae has been traditional open surgery, but it is associated with significant morbidity and mortality. Minimally invasive approaches offer alternatives to surgery in treating hemodynamically stable patients with such defects. In this review article, we will discuss the recent advancements in the minimally invasive management of esophageal perforations, leaks, and fistulas.

AREAS COVERED

This review includes information from case reports, case series, and clinical trials on minimally invasive management of esophageal perforations, leaks, and fistulas. The focus is on the devices, outcomes, and application of the technology.

EXPERT COMMENTARY

Minimally invasive treatment represents significant progress in the management of esophageal perforations, leaks, and fistulas. Based on current evidence, it seems safe and effective but it is evolving and more studies are needed to help draw definitive conclusions.

Covered airway stent placement for malignant tracheobronchial strictures in patients with an endotracheal tube

AIM

To evaluate the technical feasibility and safety of covered airway stent placement for malignant tracheobronchial strictures in patients with an endotracheal tube.

MATERIALS AND METHODS

Data regarding retrievable, expandable, metal stent placement under fluoroscopic guidance in 20 patients with an endotracheal tube inserted for malignant tracheobronchial strictures were retrospectively analysed. The clinical effectiveness was assessed using the following variables: technical and clinical success; procedure and stent-related complications; and duration of intubation following stent placement.

RESULTS

Stent placement was technically successful in all 20 patients (100%), and with 19 of the 20 patients (95%) showing symptomatic improvement within 5 days. The endotracheal tube could be removed during (n=7) or after (n=12) stent placement, and the mean duration of intubation following stent placement was 1.4 days (range 0-3 days). One patient could not have his endotracheal tube removed and he died 9 days following stent placement in an intubated state. There were no procedure-related complications. Stent-related complications in three patients included partial (n=2) and complete (n=1) stent migration, all of which were managed with placement of a second stent (n=2) or stent removal and placement of a second stent (n=1).

CONCLUSION

Covered airway stent placement under fluoroscopic guidance in patients with an endotracheal tube inserted for malignant tracheobronchial strictures, is both technically feasible and safe.

Malignant tracheal-mediastinal-parenchymal-pleural fistula after chemoradiation plus bevacizumab: management with a Y-silicone stent inside a metallic covered stent

Tracheal or bronchial-mediastinal fistulas are a rare entity associated to high mortality. We report a case of a 58-year-old man with an unresectable non-small cell carcinoma of the lung, treated with chemoradiation followed by bevacizumab. Approximately, 6 weeks after starting bevacizumab he developed a severe cough with copious secretions He could not lie supine due to the feeling of drowning. Investigations revealed a large tracheo-mediastinal-parenchymal-pleural fistula. Palliative management was offered with interventional bronchoscopic techniques. He was found to have a large central airway defect that obliterated almost 40% of the trachea. Under general anesthesia and positive pressure ventilation, a unique approach was used to rebuild an eroded tracheal and right main stem bronchial wall. A self-expanding metallic stent (SEMS) was placed to provide a scaffold of support, whereas a Dumon Y-stent was placed inside the SEMS. This combination allowed for a patent, stable airway; recreating the normal anatomy in a minimally invasive manner walling off the fistula. The patient was discharged 2 days after the bronchoscopic intervention, with significant palliation of his symptomatology. Eighteen months later, the upper lobe cavity persists with a stable airway and stents perfectly positioned with clinically insignificant evidence of stent related granulation in the upper trachea.

The use of self-expandable metallic stents in the airways in the adult population

The airway stents restore patency in the face of luminal compromise from intrinsic and/or extrinsic pathologies. Luminal compromise beyond 50% often leads to debilitating symptoms such as dyspnea. Silicone stents remain the most commonly placed stents worldwide and have been the "gold standard" for the treatment of benign and malignant airway stenoses over the past 20 years. Nevertheless, silicone stents are not the ideal stents in all situations. Metallic stents can serve better in some selected conditions. Unlike silicone stents, there are large and increasing varieties of metallic stents available on the market. The lack of prospective or comparative studies between various types of metallic stents makes the choice difficult and expert-opinion based. International guidelines are sorely lacking in this area.

Evaluation of the anti-migration effect of barbed prostatic stents: in vitro study in urethra-mimicking bovine pericardium phantoms

PURPOSE

This study was designed to compare the migration rates of covered stents with eight, four, and zero barbs in urethra-mimicking bovine pericardium models.

METHODS

Three types of polytetrafluoroethylene-covered retrievable self-expandable prostatic stents, with eight, four, and zero barbs, were tested in bovine pericardium models, consisting of normal saline-filled acrylic containers with tubes at both ends and a replica of the human urethra. The barbs were 2 mm in length and projected 60° toward the urinary bladder. The anti-migration force (AMF) and resistance force against stent removal (RFSR) were measured by an automatic push-pull gauge system at a fixed rate (2 mm/s).

RESULTS

Significant differences in AMF among the three stent types were detected (P < 0.001). Median AMF was far greater for eight-barbed than for four-barbed stents (11.96 vs. 7.55 N, P = 0.003). For stent removal, the difference between 4- and 8-barbed stents were not significant in median static (5.54 vs. 6.08 N, P = 0.15) or sliding (prostatic urethra, 5.32 vs. 5.59 N, P = 0.65; membranous urethra, 7.78 vs. 8.57 N, P = 0.364) RFSR. No perforations or scratched traces were observed during removal of these stents.

CONCLUSIONS

The inclusion of eight barbs projecting 60° toward the urinary bladder were not only effective against stent migration in this model but suggests that these stents may be suitable for the treatment of prostatic urethral strictures without severely irritating the tissue. However, whether these results translate into living urethral tissue is unclear, necessitating further studies.

Endoscopic closure of a tracheal access site using bioglue after transtracheal thoracoscopy in a nonsurvival canine model

OBJECTIVES

An ideal wound closure device would repair the wound with minimal complexity. In this report, we describe a simple wound closure method using BioGlue sealant.

METHOD

Eleven canines underwent transtracheal pericardial window creation under endoscopic guidance for natural orifice transluminal endoscopic surgery (NOTES). The tracheal wound was closed using BioGlue sealant. The integrity of the wound was assessed by determining the amount of air leaking under mechanical ventilation.

RESULTS

Transtracheal thoracic exploration and pericardial window creation was successful for all of the canines, and adequate wound closure was achieved in 10 of the canines. There was 1 case of NOTES-related death arising from misplacement of the endotracheal tube in the left lower lobar bronchus. This caused a collapse of the left upper lobe and ventilatory failure. Minor lung injuries occurred in 3 canines and minor mediastinal bleeding was encountered in 1 canine during the creation of the access site.

CONCLUSION

BioGlue sealant was found to be effective in sealing the tracheal wound in all but 1 of the canines. This study demonstrates that the use of the sealant is a simple and efficient means of endoscopically closing the tracheal access site in NOTES.

[Sealing of airway fistulas for metallic covered z-type stents]

背景与目的

气道瘘包括食管气管瘘、支气管胸膜瘘和气管纵隔瘘，临床治疗较为棘手。本文旨在探讨被膜金属支架封堵气道瘘的疗效和安全性。

方法

回顾性分析32例食管气管瘘、5例支气管胸膜瘘和1例气管纵隔瘘患者在气管镜和/或X线透视下放置被膜金属支架。原发病为食管肿瘤26例，肺癌11例，甲状腺癌1例。

结果

38例患者共有46个瘘口，口径0.5 cm-7.0 cm。放置Z型气管被膜金属支架40枚(其中Y形24枚，L形8枚和I形8枚)。食管放置被膜金属支架24枚。46个瘘口封堵疗效：治愈2例(4.3%)，临床完全缓解28例(60.9%)，部分缓解11例(23.9%)，无效5例(10.9%)，有效率为89.1%，中位生存时间为5个月。

结论

被膜金属支架能有效封堵食管气管瘘、支气管胸膜瘘和气管纵隔瘘。应首选气管支架封堵ERF，无效的患者可同时放置食管支架。分叉型气管支架尤其适于隆突周围瘘口。

Interventional management of tracheobronchial strictures

Tracheobronchial balloon dilation and stent placement have been well used in the treatment of patients with benign and/or malignant diseases. Balloon dilation is the first option in the treatment of benign airway stenosis. Although balloon dilation is simple and fast, recurrence rate is high. Stent placement promptly relieves acute airway distress from malignant extraluminal and intraluminal airway obstruction. Temporary stent placement may be an alternative for benign airway strictures refractory to balloon dilation. This article reviews the indications, pre-procedure evaluation, technique, outcomes and complications of balloon dilation and stent placement with regard to benign and malignant tracheobronchial stenoses.