Metallic Endobronchial Stents

Clinical Approach to Central Airway Obstruction in Adult Patients: Perioperative Focus on Causes and Management Including Tracheobronchial Stenting

Central airway obstruction (CAO) is a life-threatening condition associated with poor prognosis. Therapeutic bronchoscopy along with systemic therapies significantly improve survival and quality of life in patients with symptomatic benign and malignant CAO. Endoluminal therapies and tracheobronchial stenting may be used, and a multidisciplinary approach is essential for holistic management of CAO. Perioperative planning and evaluation, as well as attention to intraoperative and postoperative management are key to optimal outcomes. This review provides an overview of the etiology and clinical approach to CAO, perioperative considerations for endoluminal therapies and tracheobronchial stenting, perioperative evaluation and preparation for therapeutic bronchoscopy, and management of operative and postoperative challenges in CAO.

Anti-inflammatory coupled anti-angiogenic airway stent effectively suppresses tracheal in-stents restenosis

Excessive vascularization during tracheal in-stent restenosis (TISR) is a significant but frequently overlooked issue. We developed an anti-inflammatory coupled anti-angiogenic airway stent (PAGL) incorporating anlotinib hydrochloride and silver nanoparticles using advanced electrospinning technology. PAGL exhibited hydrophobic surface properties, exceptional mechanical strength, and appropriate drug-release kinetics. Moreover, it demonstrated a remarkable eradication effect against methicillin-resistant Staphylococcus aureus. It also displayed anti-proliferative and anti-angiogenic properties on human umbilical vein endothelial cells and lung fibroblasts. PAGL was implanted into the tracheae of New Zealand rabbits to evaluate its efficacy in inhibiting bacterial infection, suppressing the inflammatory response, reducing angiogenesis, and attenuating excessive fibroblast activation. RNA sequencing analysis revealed a significant downregulation of genes associated with fibrosis, intimal hyperplasia, and cell migration following PAGL treatment. This study provides insight into the development of airway stents that target angiogenesis and inflammation to address problems associated with TISR effectively and have the potential for clinical translation.

Silicone stent versus fully covered metallic stent in tracheoesophageal fistula: a single-center retrospective study

BACKGROUND

In cases of tracheoesophageal fistula (TEF), closure of the fistula by tracheal stent implantation is an effective treatment. In this study, we investigated the efficacy and complications of silicone and metallic tracheal stents for TEF.

METHODS

We retrospectively reviewed all patients who underwent tracheal stent insertion for TEF between January 2021 and April 2024 at our institution. Complications were assessed bronchoscopically.

RESULTS

Metallic stents were placed in 21 patients (18 men, 85.7%) and silicone stents in 17 patients (14 men, 82.4%). No differences were observed between the two groups in terms of age, gender, location or size of fistula, primary disease, symptoms or comorbidities. A total of 26 fistulas were found in the metallic stent group, and 19 fistulas were found in the silicone stent group. Stent insertion was successful in all cases. The differences in efficacy and complications after stent placement were not statistically significant between the two groups. Mucus retention was the most frequent complication (P = 0.221), followed by granulation tissue (38.1% with metallic stent and 29.4% with silicone; P = 0.734) and migration (14.3% with metallic stent and 29.4% with silicone; P = 0.426).

CONCLUSIONS

Silicone and metallic stents are viable clinical options for treating TEF. Both are equally effective and safe and have acceptable complication rates in TEF.

Study on the complications after implantation of different types of metal stents in rabbit trachea

OBJECTIVE

To observe the complications and inflammatory responses caused by the different types of metal stents in the trachea of rabbits.

METHOD

79 rabbits were randomly divided into 4 groups and were implanted with the customized nickel-titanium alloy metal stents(fully covered metal stent: group A, bare metal stent: group B, segmented covered metal stent: group C and control group: group D). The complications (tracheal deformation, granulation tissue hyperplasia, scar hyperplasia and secretion retention) of different types of metal stents were compared by observing the anatomical and pathological specimens of dead rabbits; And the expression of inflammatory factors of different types of metal stents were compared by detecting the tissue of tracheas of dead rabbits.

RESULTS

(1)There were significant differences in the above four complications among groups A, B and C(p < 0.01). The incidences of tracheal deformation, scar hyperplasia and secretion retention in group A were significantly higher than that in group B(p < 0.0167), however, the incidence of granulation tissue hyperplasia in group A was significantly lower than that in group B(p < 0.0167). The incidence of scar hyperplasia in group A was significantly lower than that in group C(p < 0.0167) and there were no significant differences in other complications between these two groups(p > 0.0167). The incidences of tracheal deformation, scar hyperplasia and secretion retention in group B were significantly lower than that in group C(p < 0.0167), however, the incidence of granulation tissue hyperplasia in group B was significantly higher than that in group C(p < 0.0167). (2)The concentration of IL-1β in group A was higher than that in group B (p < 0.05 and foldchange>1.2).

CONCLUSION

(1)There are significant differences in complications between the fully covered metal stent, bare metal stent and segmented covered metal stent; the incidences of complications between the segmented covered metal stent and fully covered metal stent are similar. (2)Changes in different inflammatory factors can be observed between the fully covered and bare metal stent.

The Development of Lung Tissue Engineering: From Biomaterials to Multicellular Systems

The challenge of the treatment of end-stage lung disease poses an urgent clinical demand for lung tissue engineering. Over the past few years, various lung tissue-engineered constructs are developed for lung tissue regeneration and respiratory pathology study. In this review, an overview of recent achievements in the field of lung tissue engineering is proposed. The introduction of lung structure and lung injury are stated briefly at first. After that, the lung tissue-engineered constructs are categorized into three types: acellular, monocellular, and multicellular systems. The different bioengineered constructs included in each system that can be applied to the reconstruction of the trachea, airway epithelium, alveoli, and even whole lung are described in detail, followed by the highlight of relevant representative research. Finally, the challenges and future directions of biomaterials, manufacturing technologies, and cells involved in lung tissue engineering are discussed. Overall, this review can provide referable ideas for the realization of functional lung regeneration and permanent lung substitution.

Airway Esophageal Fistula

Acquired tracheoesophageal fistulas (TEFs) are rare pathologic connections between the trachea and esophagus. Esophageal and tracheal stenting have been increasingly and safely utilized in management of TEFs, but surgical repair remains the most definitive treatment. Surgical approach to treating TEFs depends on its location, but principles include division and closure of the fistula tracts and insertion of a muscle flap in between the repairs to buttress and prevent recurrence. Advances in diagnostic tools, endoscopic and surgical methods, and intensive care have led to significantly improved outcomes in the management of acquired TEFs.

Custom silicone Y-stents for the management of anastomotic stenosis in lung transplant recipients

BACKGROUND

Airway stenting may be needed to manage anastomotic complications in lung transplant recipients. Conventional stenting strategies may be inadequate due to anatomic variations between the recipient and donor or involvement of both the anastomosis and lobar bronchi.

METHODS

We investigated the efficacy of 3D-designed patient-specific silicone Y-stents in managing this scenario. 9 patients with complex airway stenosis underwent custom stent insertion after either failing traditional management strategies or having anatomy not suitable for conventional stents. CT images were uploaded to stent design software to make a virtual stent model. 3D printing technology was then used to make a mold for the final silicone stent which was implanted via rigid bronchoscopy. Forced expiratory volume in 1 s (FEV1) was measured pre- and post-stent placement.

RESULTS

78 % of patients experienced an increase in their FEV1 after stent insertion, (p = 0.001, 0.02 at 30 and 90 days respectively). Unplanned bronchoscopies primarily occurred due to mucous plugging. 2 patients had sufficient airway remodeling allowing for stent removal.

CONCLUSIONS

Personalized 3D-designed Y-stents demonstrate promising results for managing complicated airway stenosis, offering improved lung function and potential long-term benefits for lung transplant recipients.

Graphene oxide-loaded rapamycin coating on airway stents inhibits stent-related granulation tissue hyperplasia

OBJECTIVES

Our objective was to explore the safety and efficacy of a graphene oxide-loaded rapamycin-coated self-expandable metallic airway stent (GO@RAPA-SEMS) in a rabbit model.

METHODS

The dip coating method was used to develop a GO@RAPA-SEMS and a poly(lactic-co-glycolic)-acid loaded rapamycin-coated self-expandable metallic airway stent (PLGA@RAPA-SEMS). The surface structure was evaluated using a scanning electronic microscope. The in vitro drug-release profiles of the 2 stents were explored and compared. In the animal study, a total of 45 rabbits were randomly divided into 3 groups and underwent 3 kinds of stent placements. Computed tomography was performed to evaluate the degree of stenosis at 1, 2 and 3 months after the stent operation. Five rabbits in each group were sacrificed after the computed tomography scan. The stented trachea and blood were collected for further pathological analysis and laboratory testing.

RESULTS

The in vitro drug-release study revealed that GO@RAPA-SEMS exhibited a sudden release on the first day and maintained a certain release rate on the 14th day. The PLGA@RAPA-SEMS exhibited a longer sustained release time. All 45 rabbits underwent successful stent placement. Pathological results indicated that the granulation tissue thickness in the GO@RAPA-SEMS group was less than that in the PLGA@RAPA-SEMS group. The TUNEL and hypoxia-inducible factor-1α staining results support the fact that the granulation inhibition effect in the GO@RAPA-SEMS group was greater than that in the PLGA@RAPA-SEMS group.

CONCLUSIONS

GO@RAPA-SEMS effectively inhibited stent-related granulation tissue hyperplasia.

A multicenter observational study assessing the safety, feasibility, and complications of Bonastent in central airway obstruction

BACKGROUND

Self-expandable metallic stents (SEMS) are increasingly used in the management of both malignant and nonmalignant airway stenosis. There are multiple stents available in the market; however, the current literature on the efficacy and safety of newly available 3rd generation SEMS (Bonastent) is extremely limited and only has data from single center studies.

OBJECTIVES

To report the efficacy and early (<7 days) and late (⩾7 days) complications in patients with central airway obstruction (CAO) treated with Bonastent placement at two institutions.

DESIGN

We performed a retrospective analysis of data of consecutive patients who underwent therapeutic bronchoscopy and Bonastent placement at two tertiary care university hospitals between January 2019 and November 2023.

METHODS

Bonastent deployment was performed in the operating room. Stents were deployed using rigid or flexible bronchoscopy under direct visualization with a flexible bronchoscope and in conjunction with fluoroscopic guidance. We then analyzed the effectiveness, short-term, and long-term complications of Bonastent placement.

RESULTS

A total of 107 Bonastents® were placed in 96 patients. The most common etiology of CAO was malignancy, 92.7% (n = 89), followed by excessive dynamic airway collapse (EDAC) and post-intubation tracheal stenosis. Seventy-three patients (76%) had improvement in symptoms or imaging within 7 days of stent placement, including successful liberation from mechanical ventilation in a patient with CAO. Early complications occurred in seven patients (two-airway bleeding, two-mucus plugging that improved with airway clearance, two-stent migrations, and one-cough).Late complications occurred in 23 patients (1-stent migration requiring revision bronchoscopy and replacement of airway stent, 11-mucus plugging, 6-granulation tissue, 2-pneumonia, 1-cough, 1-tumor ingrowth/stent fracture, 1-airway emergency due to excessive granulation tissue obstructing the distal end of the stent and had a failed cricothyroidotomy leading to death). Overall, the early complication rate was 7.3% (7/96) and late complication rate was 23.9% (23/96).

CONCLUSION

Our study is the first multicenter study that found a good safety profile with a low complication rate after tracheobronchial Bonastent placement with improvement in symptoms soon after stent placement.

Advancements in airway stents: a comprehensive update

PURPOSE OF REVIEW

This review provides an overview of the evolving field of airway stenting (AS), highlighting its relevance in the management of central airway obstruction (CAO). It discusses recent advancements, including 3D-printed silicone stents (3DPSS), metallic stents, biodegradable stents (BS), and drug-eluting stents (DES), which are transforming clinical practice. The review underscores the ongoing challenges in patient selection, stent choice, and long-term management in the context of an evolving landscape.

RECENT FINDINGS

Innovations, particularly 3DPSS, have shown promise in providing patient-specific solutions. These stents offer improved symptom relief, enhanced quality of life, and lower complication rates, especially for complex airway diseases. The use of BS and DES is explored, raising prospects for future applications.

SUMMARY

The evolution of AS reflects a deepening understanding of airway obstructions. Recent innovations, such as 3DPSS, BS, and DES, show considerable promise in addressing the limitations of conventional stents. However, challenges related to complications, patient selection, and long-term management persist, demanding further research. Wide practice variations in the management of AS highlight the need for more clinical data and standardized guidelines. The search for the ideal stent continues, driven by the pursuit of better outcomes for patients with CAO.

Forbearance with endobronchial stenting: cognisance before conviction

Endobronchial stenting is an important aspect of the practice of interventional pulmonology. The most common indication for stenting is the management of clinically significant airway stenosis. The list of endobronchial stents available on the market continues to grow. More recently, patient-specific 3D-printed airway stents have been approved for use. Airway stenting should be considered only when all other options have been exhausted. Due to the environment of the airways and the stent-airway wall interactions, stent-related complications are common. Although stents can be placed in various clinical scenarios, they should only be placed in scenarios with proven clinical benefit. The unwarranted placement of a stent can expose the patient to complications with little or no clinical benefit. This article reviews and outlines the key principles of endobronchial stenting and important clinical scenarios in which stenting should be avoided.

A single-tube-braided stent for various airway structures

Background: Airway stent has been widely used in airway procedures. However, the metallic and silicone tubular stents are not customized designed for individual patients and cannot adapt to complicated obstruction structures. Other customized stents could not adapt to complex airway structures with easy and standardized manufacturing methods.

Object: This study aimed to design a series of novel stents with different shapes which can adapt to various airway structures, such as the “Y” shape structure at the tracheal carina, and to propose a standardized fabrication method to manufacture these customized stents in the same way.

Methods: We proposed a design strategy for the stents with different shapes and introduced a braiding method to prototype six types of single-tube-braided stents. Theoretical model was established to investigate the radial stiffness of the stents and deformation upon compression. We also characterized their mechanical properties by conducting compression tests and water tank tests. Finally, a series of benchtop experiments and ex vivo experiments were conducted to evaluate the functions of the stents.

Results: The theoretical model predicted similar results to the experimental results, and the proposed stents could bear a compression force of 5.79N. The results of water tank tests showed the stent was still functioning even if suffering from continuous water pressure at body temperature for a period of 30 days. The phantoms and ex-vivo experiments demonstrated that the proposed stents adapt well to different airway structures.

Conclusion: Our study offers a new perspective on the design of customized, adaptive, and easy-to-fabricate stents for airway stents which could meet the requirements of various airway illnesses.

Comparison of three kinds of self-expandable metallic stents induced granulation tissue hyperplasia in the rabbit trachea

To compare stent-induced granulation tissue hyperplasia of bare (SEMS), polyurethane-covered (PU-SEMS) and electrospun nanofibre-covered (EN-SEMS) self-expandable metallic stents in the rabbit trachea. Twenty-seven rabbits were randomly assigned to 3 groups that received SEMS, PU-SEMS or EN-SEMS. Computed tomography and sacrifice were performed as scheduled. Haematoxylin–eosin and Masson’s trichrome staining protocols were performed for pathological analysis. The data for tracheal ventilation area ratio, qualitative histological scoring, number of epithelial layers, and thicknesses of papillary projection and submucosa were documented and statistically analysed. All stents were successfully placed under the guidance of fluoroscopy without complications. Post-stenting 3 and 7 days, computed tomography revealed that the fully expandable EN-SEMS was similar to the SEMS and PU-SEMS. The mean stented tissue score in the SEMS group was higher than those of both the PU-SEMS and EN-SEMS groups at 3 days post-stenting. The pathological findings suggested that there was no papillary projection formation 3 days after stent placement. The thickness of papillary projection in the SEMS group was significantly higher than those of the PU-SEMS and EN-SEMS groups at 7 days post-stenting. After stenting 4 weeks, the tracheal ventilation area ratio of SEMS, PU-SEMS and EN-SEMS was 0.214 ± 0.021, 0.453 ± 0.028 and 0.619 ± 0.033, respectively. There were significant between-group differences. In conclusion, the stent-induced granulation tissue formation in EN-SEMS is less severe than that of PU-SEMS and SEMS. EN-SEMS has smaller radial force, and the tracheal ventilation ratio after stent placement better than that of PU-SEMS.

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.

Customization of stent design for treating malignant airway stenosis with the aid of three-dimensional printing

Background

The treatment of malignant stenosis involving the carina or bronchi is challenging due to complicated anatomy with individual variation, which makes it necessary to customize stents for each patient. Therefore, this study aims to evaluate the feasibility of a novel metallic segmented airway stent customized with the aid of three-dimensional (3D) printing for such cases.

Methods

The stents were individually customized with the aid of a 3D printed mold based on computed tomography (CT) images according to the anatomical features of the airway. A segmented design was applied on the junction part of the main stem and the branches to fit the dynamic changes of the carina angle. In 12 patients with airway stenosis caused by malignancies including esophageal cancer (EC) and lung cancer (LC), the stents were implanted. The technical and clinical success of the stenting procedure, Hugh-Jones (HJ) classification, Karnofsky performance status (KPS), and stent-related complications of patients were evaluated.

Results

The stenting procedure was technically successful in all patients, and 11 patients showed significant palliation of dyspnea after stenting. The HJ and KPS classification of patients after stent insertion improved significantly compared with those before stenting (P=0.003 and P=0.006, respectively). During follow-up, granulation tissue proliferation and sputum retention were found in two and four patients, respectively.

Conclusions

This study shows that the implantation of a novel stent designed with the aid of 3D printing is feasible for relieving dyspnea and improving performance status of patients with inoperable malignant stenosis involving the carina or bronchi.

A flexible porous chiral auxetic tracheal stent with ciliated epithelium

Tracheal stent placement is a principal treatment for tracheobronchial stenosis, but complications such as mucus plugging, secondary stenosis, migration, and strong foreign body sensation remain unavoidable challenges. In this study, we designed a flexible porous chiral tracheal stent intended to reduce or overcome these complications. The stent was innovatively designed with a flexible tetrachiral and anti-tetrachiral hybrid structure as the frame and hollows filled with porous silicone sponge. Detailed finite element analysis (FEA) showed that the designed frame can maintain a Poisson's ratio that is negative or close to zero at up to 50% tensile strain. This contributes to improved airway ventilation and better resistance to migration during physiological activities such as respiration and neck movement. The preparation process combined indirect 3D printing with gas foaming and particulate leaching methods to efficiently fabricate the stent. The stent was then subjected to uniaxial tension and local radial compression tests, which indicated that it not only has the same desirable auxetic performance but also has flexibility similar to the native trachea. The porous sponge facilitated the adhesion of cells, allowed nutrient diffusion, and would prevent the ingrowth of granulation tissue. Furthermore, a ciliated tracheal epithelium similar to that of the native trachea was differentiated from normal human bronchial primary epithelial cells on the internal wall of the stent under air-liquid interface conditions. These results suggest that the designed stent has the potential for application in the treatment of tracheobronchial stenosis.

Arsenic trioxide-eluting electrospun nanofiber-covered self-expandable metallic stent reduces granulation tissue hyperplasia in rabbit trachea

Stent-related granulation tissue hyperplasia is a major complication that limits the application of stents in airways. In this study, an arsenic trioxide-eluting electrospun nanofiber-covered self-expandable metallic stent (ATO-NFCS) was developed. Poly-L-lactide-caprolactone (PLCL) was selected as the drug-carrying polymer. Stents with two different ATO contents (0.4% ATO/PLCL and 1.2% ATO/PLCL) were fabricated. The in vitro release in simulated airway fluid suggested that the total ATO release time was 1 d. The growth of human embryonic pulmonary fibroblasts (CCC-HPF-1), normal human bronchial epithelial cells and airway smooth muscle cells was inhibited by ATO. When embedded in paravertebral muscle, the nanofiber membrane showed good short-term and long-term biological effects. In an animal study, placement of the ATO-NFCS in the trachea through a delivery system under fluoroscopy was feasible. The changes in liver and kidney function 1 and 7 d after ATO-NFCS placement were within the normal range. On pathological examination, the heart, liver, spleen, lungs and kidneys were normal. The effectiveness of the ATO-NFCS in reducing granulation tissue hyperplasia and collagen deposition was demonstrated in the rabbit airway (n = 18) at 4 weeks. The present study preliminarily investigated the efficacy of the ATO-NFCS in reducing granulation tissue formation in the trachea of rabbits. The results suggest that the ATO-NFCS is safe in vivo, easy to place, and effective for the suppression of granulation tissue formation.

Clinical outcomes and survival following placement of self-expandable metallic stents for central airway stenosis and fistula

Background

Self‐expandable metallic stent (SEMS) placement is an urgent procedure for patients with malignant central airway stenoses (CASs) and central airway fistulas (CAFs). The aim of this study was to determine the outcome and survival after SEMS placement in patients with malignant CASs and CAFs.

Methods

SEMSs were inserted into 20 patients with malignant CASs and four with malignant CAFs. Hospital records, the modified Medical Research Council dyspnea scale (mMRC) grade, performance status (PS), symptoms, procedure‐related complications and survival after placement were retrospectively reviewed.

Results

Spiral Z stents were inserted in nine patients, covered Ultraflex stents in 14, and a bare Ultraflex in one patient. After SEMS placement, 20 patients (83.3%) showed improvement in mMRC grade, 19 (79.2%) showed improvement in PS, and 21 (87.5%) showed improvement in symptoms. There were three patients whose stents migrated out of place, but there were no patients with obstructive granulation, infection, or mucous plugs. Median survival days after stent insertion was 98 days for CAS and 103 days for CAF, and mean survival days was 383 ± 707 days for CAS and 93 ± 33 days for CAF. Two patients with CAS by malignant lymphoma and thymic cancer survived more than six years because they were also treated with efficient therapies. The five‐year survival rate after stent insertion was 7.7%.

Conclusions

SEMS placement for CAS and CAF is associated with improvement in mMRC grade, PS and symptoms in 87.5% of patients. Patients with a malignant CAS are usually terminal, but the possibility of increasing survival rate will become a reality with new efficient therapies.

Key points

Significant findings of the study

Reasonable clinical outcomes and improved survival of patients following SEMS placement for thoracic malignancy with central airway stenosis and fistula.

What this study adds

The possibility of increasing survival rate will become a reality with new efficient therapies.

Bronchoscopic treatment of inoperable nonsmall cell lung cancer

Patients with unresectable lung cancer range from those with early-stage or pre-invasive disease with comorbidities that preclude surgery to those with advanced stage disease in whom surgery is contraindicated. In such cases, a multidisciplinary approach to treatment is warranted, and may involve medical specialties including medical oncology, radiation oncology and interventional pulmonology. In this article we review bronchoscopic approaches to surgically unresectable lung cancer, including photodynamic therapy, brachytherapy, endoscopic ablation techniques and airway stenting. Current and past literature is reviewed to provide an overview of the topic, including a highlight of potential emerging approaches.

Management of tracheo-oesophageal fistula in adults

Tracheo-oesophageal fistula (TOF) is a pathological connection between the trachea and the oesophagus that is associated with various underlying conditions including malignancies, infections, inhalation injuries and traumatic damage. As the condition spans multiple organ systems with varying aetiologies and acuities, TOF poses unique diagnostic and management challenges to pulmonologists, gastroenterologists and thoracic surgeons alike. Although stents have been a cornerstone in the management of TOF, there exists a large gap in our understanding of their efficacy and precise methodology, making stenting procedure both art and science. TOFs relating to underlying oesophageal or tracheal malignancies require advanced understanding of the airway and digestive tract anatomy, dimensions of the fistula, stent characteristics and types, and the interplay between the oesophageal stent and the airway stent if dual stenting procedure is elected. In this review article, we review the most up-to-date data on risk factors, clinical manifestations, diagnostic approaches, management methods and prognosis. Consequently, this article serves to evaluate current therapeutic strategies and the future directions in the areas of 3D-printed stents, over-the-scope clipping systems, tissue matrices and atrial septal closure devices.

Safety and Efficacy of the Tracheobronchial Bonastent: A Single-Center Case Series

BACKGROUND

Tracheobronchial stents are widely used devices in interventional pulmonology; however, the current literature on the effectiveness and complication rates of the different types of stents is limited.

OBJECTIVE

We report the largest case series of airway Bonastent placement and describe the efficacy and early (<30 days) and late (≥30 days) complication rates.

METHODS

We performed a retrospective review of our prospectively collected database of patients who underwent therapeutic bronchoscopy with stent placement. All adult patients who had a tracheal/bronchial Bona-stent placed between July 1, 2017, and July 30, 2019, for any indication at our institution were included. The efficacy as well as intraoperative and short- and long-term complications of Bonastent placement were evaluated.

RESULTS

Sixty Bonastents were placed in 50 patients. The etiology was malignant in 90% of the cases, while 2 patients had a tracheoesophageal fistula. All procedures were performed via rigid bronchoscopy. The most common location for stent placement was the bronchus intermedius, followed by the trachea, in 32 and 30% of the cases, respectively. Seventy percent of the patients (35/50) had improvement of respiratory symptoms within 30 days. Twenty-eight stents (48%) were removed at a mean of 74 days. Seventeen patients (34%) died within 30 days of stent placement. The overall complication rate was 54% (27/50 patients) at a mean follow-up of 111 days. The stent-related complication rate was 23.3% (14/60 cases) within <30 days and 53% (18/34 cases) at ≥30 days.

CONCLUSIONS

The tracheobronchial Bonastent is effective for the treatment of patients with central airway obstruction and tracheoesophageal fistulae with an acceptable safety profile.

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.

Intermediate bronchial fistula caused by mediastinal drainage tube compression and fungal infection: a case report

Background

Intermediate bronchial fistula formation caused by mediastinal drainage tube compression and fungal infection is rare.

Case presentation

A 50-year-old male patient with type 2 diabetes was observed air filling in mediastinal drainage tube, 12 days after esophagectomy for esophageal squamous carcinoma. Based on the results of computed tomography, bronchoscopy and pathology, the diagnosis of intermediate bronchial fistula caused by mediastinal drainage tube compression and fungal infection was made. Anti-fungal drug and temporary covered metallic stent was used. After stent removed, the fistula was healed with some granulation hyperplasia. He was free from respiratory symptom during 1 year follow-up.

Conclusion

Intermediate bronchial fistula caused by the combination of mediastinal drainage tube compression and fungal infection is rare. Timely stenting could boost the healing of fistula via granulation tissue proliferation.

Anesthetic considerations for bronchoscopic procedures: a narrative review based on the Cleveland Clinic experience

The advent of advanced diagnostic bronchoscopy has shown an increased demand for anesthesiologists to administer anesthesia in the bronchoscopy suite. Procedures such as navigational bronchoscopy, airway stenting and advanced therapeutic procedures often require the presence of an anesthesiologist to manage these more complex patients and procedures. In this review we describe the various bronchoscopic procedures and anesthetic management and complications of these procedures at our institution The Cleveland Clinic, Cleveland Ohio.

Broncholithiasis: A Review

The term "broncholithiasis" is defined as the presence of calcified or ossified materials within the tracheobronchial tree. The report of the condition dates back to 300 bc when Aristotle first described a symptom of "spitting of stones." The process of calcification usually starts within either the mediastinal, hilar, or peribronchial lymph nodes. The impetus is typically initiated by a granulomatous process such as TB or histoplasmosis; however, it can also been seen following exposure to other fungal or occupational elements. The exact mechanism of the calcified material (broncholith) entering the endobronchial tree remains unknown. It is hypothesized, however, that the calcified tissues gradually erodes and/or breaks loose in the airways as a result of repetitive movements of respiration or cardiac pulsations. The broncholiths are often found in the airways without any signs of erosion, however. The most common symptoms of broncholithiasis include cough, hemoptysis, and wheezing as a result of irritation of the airways and the surrounding tissues. The diagnosis is typically suspected on chest radiographs and confirmed by using bronchoscopy. Depending on the severity of the disease, management options range from simple observation to surgical resection. Despite the potential for major complications, the overall disease prognosis is good if timely and appropriate management is provided.