The role of bronchoscopy in benign airway stenosis: literature review of a central procedure guiding multidisciplinary care and therapeutic approach for improving patient outcomes

Introduction

Tracheal stenosis is a potentially life-threatening condition, but it is frequently misdiagnosed. Patients with airway stenosis suffer from dyspnea, wheezing, cough and retention of secretions that are symptoms of more common diseases such as asthma or chronic obstructive pulmonary disease (1). Patients with tirage and cornage generally suffered from severe tracheal stenosis, and it is estimated that the lumen of the airway is reduced up to 75% of normal caliber (2). Herein, we report a brief review on role of bronchoscopy in the diagnosis and as a treatment option, evaluating advantages, disadvantages and controversies of different techniques.

Rare causes of benign tracheal stenosis include gastro-esophageal reflux disease, airway infection, neck or mediastinum radiation therapy, inhalation or chemical injury, autoimmune disorders, such as granulomatosis with polyangiitis (3,4). However, in these cases the pathogenesis is unclear. The repair of a damaged soft tissue is a multifactorial process, consisting of subsequent phases that can overlap in space and time: haemostasis, inflammation, proliferation, and maturation/remodeling. Any variation from this typical sequence can lead to dysfunctional wound repair, leading to fibrosis. It is supposed that the aberrant fibroinflammatory scarring process, related to immunological alteration and complex irregular interaction involving growth factors, cytokines and altered fibroblast, can be induced after an injury, often unknown as in patients with granulomatosis with polyangiitis, that acts as a trigger (5). When no cause is evident after a complete anamnesis, the tracheal stenosis can be defined idiopathic. It generally affects young women (between the third and fifth decades of life) and its incidence is estimated about 1:400,000 (4). When a trigger takes place in the airway tree, fibrotic stenosis may occur. However, iatrogenic aetiology (endotracheal intubation or tracheotomy) still remains the main cause of subglottic or tracheal stenosis (4,6,7). With regard to post-intubation stenosis, the main cause is related to the pressure of cuff of the endotracheal tube. The tracheal vascularization is circumferential, thus the excessive pressure (>30 cmH₂O) of the tube cuff can produce an ischemic injury of the wall, with consequent circumferential scarring of the interested portion of trachea (8,9). Additional risk factors for post-intubation tracheal stenosis consist of traumatic intubation, long duration of intubation (>14 days) and prone positioning. The other iatrogenic cause is represented by percutaneous tracheotomy that may cause a direct damage of cartilaginous rings of the trachea, especially when performed at a high site. Risk factors for post-tracheotomy tracheal stenosis include excessive strength used during tracheostomy procedure with cartilage fracture, regional ischemic necrosis, infection at the site of the tracheostomy (8,10). Moreover, the distal part of the cannula may produce an additional damage by rubbing on tracheal wall, often causing a stricture at a second lower level (10). Overall risk factors for both post intubation and post tracheotomy stenosis include previous radiation, obesity, gastro-esophageal reflux disease and diabetes (9,10). However, aetiology of tracheal stenosis still remains undiagnosed in 18% of the cases (11). We present this article in accordance with the Narrative Review reporting checklist (available at https://jovs.amegroups.com/article/view/10.21037/jovs-24-29/rc).

Methods

This narrative review was based on searches in PubMed and Google Scholar databases. Keywords used for the research included “benign tracheal stenosis”, “benign airway stenosis”, “rigid bronchoscopy”, “mechanical dilatation”, “laser application”, “drugs submucosal application” and “tracheal stent”.

We searched for published articles between and 2023. Paper not in English was excluded. Pediatric papers were excluded. Duplicate articles were excluded (Table 1). The aim of this review is to give a brief overview of the role of bronchoscopy, providing fundamental basics when approaching benign tracheal stenosis and focusing of different endoscopic treatments.

The role of bronchoscopy in the diagnosis

Chest and neck computed tomography (CT) scan are non invasive procedures routinely performed for analysis of airway, allowing to see the integrity of airway wall, possible ossification or damage of cartilage. Additionally, it can gives information regarding possible hypertrophic tissues surrounding the tracheobronchial tree and relationship with epiaortic vessels (12,13). In the last decades, 3D reconstruction with multi planar views has been developed (Figure 1A,1B), and more recently virtual bronchoscopy (Videos 1,2) was reported for the study of airway-tree (14-17). However, bronchoscopy still remains mandatory because it allowing direct visualization of airway mucosa and evaluation of airway wall (Video 3), also during breathing (dynamic stenosis), measurement of the narrow (site, length, shape) and assessment of vocal cord function. In case of presence of tracheostomy cannula, it necessary to remove it during evaluation, in order to obtain a complete airway inspection. For the same reason, if the patient is intubated, the endotracheal tube should be retracted as proximally as possible. Several classifications are available for tracheal stenosis, but two grading systems are widely accepted: the Myer-Cotton system divides the stenosis in four group, basing on grade of cross-section area measured with an endotracheal tube, with the limit of not considering the length or complexity of the lesions (18), and the McCaffrey system classify the stenosis on the basis of location and length (19). Bronchoscopic evaluation should be objective: it must evaluate the degree, the length, the morphology (circumferential, elliptical) and the complexity (with or without wall damage) of the stenosis. Additionally, the precise position of the stenosis in respect to the vocal cords, the cricoid, and the main carina must be assessed.

Figure 1 Multi-planar 3D reconstruction of airway tree, performed by using thorax CT scan. (A) Multi-planar 3D reconstruction of a patients with stenosis due to previous tracheotomy that was performed 8 months before, during a recovery in Intensive Care Unit for an acute respiratory failure. (B) Multi-planar 3D reconstruction of CT scan of patient that suffered from stenosis of the right main bronchus related to radiation therapy, performed several years before due to right breast cancer. The yellow dot was the target zone identified on planar CT scan, in order to plot a route through the trachea and the right main bronchus, producing the virtual bronchoscopy (see Video 2). The green numbers 1, 2 and 3 indicate the possible routes in order to achieve the yellow dot. The pathway number 1, that is represented by the yellow line that runs through the trachea and the right main bronchus, was chosen in order to produce the virtual bronchoscopy of Video 2. CT, computed tomography.

Severity of stenosis

The bronchoscopist should measure the narrowing and compare its cross-section area to a normal segment of the trachea, in order to classify it as severe (reduction more than 70%) (Figure 2A), mild (reduction less than 50%) (Figure 2B) or moderate (reduction between 51% and 70%). The severity of stenosis impacts on symptoms, especially dyspnea, that appear to be mostly related to the percentage reduction in airway caliber rather than the absolute decrease in the airway diameter (20). Patients with mild stenosis generally don’t suffer from symptoms, even with exertion, because the pressure gradient, occurring across the stenosis, is similar to that developed during a normal glottis opening. On the other hand, patients with moderate stenosis suffer from symptoms during exertion, while patients with severe stenosis, experience symptoms even at rest. However, also other comorbidities may cause dyspnea and so increase symptoms. The precise assessment of severity of stenosis is crucial, and some authors in recent studies suggest the use morphometric bronchoscopy assessment in respect to bronchoscopic images, because it may be variable and subjective (21,22).

Figure 2 Endoscopic images preformed during bronchoscopy in order to asses the severity, the shape and the length of the stenosis. (A) Severe tracheal stenosis in a patient that underwent intubation during recovery in intensive care unit for COVID-19 related acute respiratory failure. (B) Mild tracheal stenosis in a patient that underwent prolonged intubation during recovery in intensive care unit for COVID-19 related acute respiratory failure. COVID-19, coronavirus disease 2019.

Extent and location

The endoscopist has to put the tip of the bronchoscope at the level of the distal limit of the stenosis and retract it up to the proximal end: so the distance can be measured on the bronchoscope. The shape of the stenosis and whether there is multifocal disease should be described. In addition, the distance should be measured between the distal edge of the stenosis and the main carina, and between the proximal edge of the stenosis and the vocal cords. Moreover, involvement of the cricoid cartilage and the subglottic larynx should be clearly identified. The correct extent of tracheal stenosis is essential for deciding the best therapeutic option: stenosis shorter than 1 cm without cartilage involvement are endoscopically treated with mechanical dilation with good results (23). Surgical resection is considered a definitive treatment for strictures that are 1–4 cm in length, while stenosis longer than 4–6 cm are generally excluded from surgery due to risks for tension and anastomotic complications (24). Therefore, precise measurement of the extent of tracheal stenosis is essential during bronchoscopic evaluation.

Morphology

The endoscopist has to evaluate the status of the mucosa, the presence of hypertrophic tissue or scar tissue and the integrity of tracheal wall that can produce a dynamic stenosis during breathing. A stenosis less than 1 cm in extension without malacia can be defined as simple (Figure 3A). A stenosis longer than 1 cm in length or with associated malacia or full thickness tracheal wall injury can be defined complex (Figure 3B), and generally has poor response to endoscopic dilation alone. Thus, describing the shape of the stenosis and cartilage damage are important factors for treatment decisions and outcomes.

Figure 3 Endoscopic images preformed during bronchoscopy in order to assess the severity, the shape and the length of the stenosis. (A) Simple idiopathic tracheal stenosis in a young woman. (B) Tracheal complex stenosis related with a previous tracheotomy: the helicoidal shape suggest a damage of tracheal rings at the level of tracheotomy.

The role of bronchoscopy in the treatment

The choice of appropriate treatment and its timing should be taken in a multi-disciplinary setting, based not only on the features of the stenosis, but also on patients’ s general conditions. Some authors considered surgical resection the preferred treatment for most patients with benign tracheal stenosis, especially for complex ones, with a length less than 4 cm (25-27). They reserve the endoscopic approach only as a bridge therapy to optimize the timing of surgery or for those patients not eligible for surgical intervention (length >4–6 cm), even if tracheal replacement with cryopreserved aortic allograft for long stenosis was anecdotally reported (28,29). Additionally, bronchoscopic interventions plays a role in management of anastomotic complications (30), that in literature occur in a variable range (1.5% and 13.4%) and that may lead to a re-stenosis (26,31,32).

On the other hand, other authors believe that the rigid bronchoscopy could be considered an effective treatment in the majority of patients with tracheal stenoses, only when a correct classification of stenosis is performed and where the endoscopic procedures, such as mechanical dilatation, laser and stent positioning are well standardized (23,33). Additionally, the presence of systemic inflammatory disorder and autoimmune condition may move forward for an endoscopic approach (4,23).

Bronchoscopic interventions include laser-assisted mechanical dilation with rigid bronchoscopy and/or balloon dilation, and in refractory or complex lesions, silicone stent insertion may be considered (34-36). Some authors reported the intralesional steroid injection or mitomycin C application (37-39). Herewith, we propose a brief summary of several treatment approaches, analyzing possible benefits.

Mechanical dilatation

It can be performed with flexible bronchoscope, but several studies recommend to use rigid bronchoscope because it offers the possibility of a dilation under direct visual control, allowing airways’ patency and ventilation, permitting the introduction of several tools at the same time (Video 4), in order to better front possible complications (23,40). Dilatation can be obtained with gentle insertion of rigid bronchoscope with progressively increasing diameter or with a dilatators balloon (Video 5) (41). Mechanical dilatation should be accomplished with “mucosal sparing technique” (Videos 6-8), consisting in three radial incisions of mucosa, generally performed at 12, 4 and 8 o’clock (34,35,42). Mucosal sparing techniques minimize airway trauma, facilitating the introduction of the rigid bronchoscope and promoting the development normal re-epithelization and airway repair. It is essential to avoid circumferential mucosal ablation, because it may induce further stenosis due to mucosa scarring and secondary retraction (35). Different energy devices can be used to make these mucosal incisions (43). The CO₂ was the first laser that was introduced to the field of medicine, but it has several disadvantages, such suboptimal hemostasis due to its shallow depth of penetration (44). Similar to the CO₂ laser, also argon plasma coagulation, that is a non contact device that use ionized gas to generate a monopolar-electric current, has shallow depth of penetration and produce a diffuse effect on the near tissue, thus it can’t be use in benign stenosis due to intense inflammatory reaction (1,45). In 1982, Dumon, described the application of Nd:YAG laser not only for treatment of obstructing malignant lesions of tracheobronchial tree but also for benign stenosis (46). Since that time onwards mechanical dilatation and laser therapy has become a standard treatment in the management of central airway obstruction. However, other energy devices can be applied during bronchoscopy in combination with mechanical dilatation, such as monopolar and bipolar instruments that require direct contact with the mucosa, such as electric energy needle-knife (47,48).

The best results with mechanical dilatation and laser therapy are observed in simple, web-like stenosis which can be potentially cured (Figure 4A), while complex one should be referred for surgery (Video 9). In post intubation stenosis, the success rate of laser assisted mechanical dilatation ranges from 60% to 95% after two to three treatment session (35). Galluccio et al. analysed 167 post-intubation and 34 post-tracheostomy stenoses, observing 96% of success in patients with simple stenosis with endoscopic therapy alone, in comparison with complex ones (79% success rate) (23). In a meta-analysis of 2011 on patients with a stenosis length of less than 1 cm without wall destruction, the success rate of an endoscopic approach was 79%, but it decreased to 47% when length is more than 1 cm (49). Laser assisted mechanical dilatation for treatment of tracheal stenosis related with systemic inflammatory and autoimmune diseases, should be supported by a systemic immunological therapy (3,4,50).

Figure 4 Post-operative bronchoscopic control. (A) Postoperative control (6 months after) in a patient treated with laser assisted mechanical dilatation for an idiopathic tracheal stenosis. (B) Dumon stent positioned in a marginal surgical patient with a complex stenosis, with the aim to restore patency till fibro-cicatricial process ends.

Drugs sub mucosal application

Steroids inhibit scar formation by interfering with collagen synthesis, fibrosis, especially in the early inflammatory stage. Some studies suggest that intralesional steroid injections after endoscopic mechanical dilatation can provide better results in terms of airway patency maintenance, above all in patients with autoimmune disease rather than in patients with idiopathic or traumatic stenosis (51,52). Mitomicina-C is a cytotoxic agent that inhibits DNA and RNA synthesis. Its topical application was studied as adjuvant therapy in benign airway stenosis, in combination with radial incision with laser and mechanical dilation (53). A meta-analysis on 387 patients showed that 70% of patients remained symptom-free one year after the endoscopic intervention, and symptom-free period appeared longer in patients treated also with submucosa injection of Mitomicina-C (54). However, its use is still debated due to controversial evidences and the possibility to produce complications (1,26,55).

Stent positioning

When patients are deemed non operable due to lesion characteristics or comorbidities, or when recurrent stenosis occurs after endoscopic mechanical dilatation, or after surgical intervention of resection/anastomosis, stent positioning can be considered a therapeutic option, with the aim to maintain the airway calibre, till the fibro-cicatricial process ends, or as a long term option for palliation (30,56,57). An airway stent can be defined as an endobronchial device made of different material that aim to restore patency of the tracheal wall. All stents are foreign bodies and in theory, the ideal stent should be stable, strong enough to maintain patency, while being flexible enough to conform to the different luminal irregularities, nonirritating, resistant to migration, easily deployable and removable: thus the ideal stent does not exist. Traditionally, airway stents are divided into two categories, the silicone stents, and the self-expandable metallic stents.

In the past, metallic stents were applied for benign stenosis. They are easy to deploy, even with flexible bronchoscope, but severe complications were reported: granulation tissue that produces recurrent obstruction inside the stent, requiring repeated debridement or repeat stenting within the preexisting stent. Such complications can impact negatively on life quality of such kind of patients that have a benign disease, in the long term period (58-61). Thus in 2005, the US Food and Drug Administration (FDA) issued a warning stating that the use of metallic stents should be avoided in benign stenosis, where stents were inevitably susceptible to adverse event, based on a relatively longer patient life expectancy (62).

Therefore, currently silicone stent (Figure 4B) can be considered the preferred stent for endoscopic treatment of benign airway stenosis (34,63). Even if silicon stent positioning, necessarily requires rigid bronchoscopy, it has the advantage of an easier removal in respect to metallic one, even several months or years after placement. In 1996, Dumon et al. reported a study on 263 patients with tracheal benign stenosis, who underwent 419 silicone stent placements with a 7-year follow-up: the stent was removed in 117 cases, without recurrence in 54.7% of cases, while the mean stent duration was 1.2 years (64).

In a study on 73 patients, Cavaliere et al. observed that most simple stenosis were successfully treated mechanical dilation alone, while the majority of complex stenosis (78%) required stent placement. In these cases, when the stent was removed after a mean period of 11.6±4.6 months, 46.8% of patients did not require any further therapy (34). Also Galluccio et al. reported that stent positioning was required in 49/200 cases of tracheal stenosis, and of these 33 were complex. At the end of the 2 years of follow-up period, 69% of patients with complex stenosis were successfully treated after stent removal. For the remaining 31% the authors left in place or repositioned a new prosthesis for palliative purpose (23). In the STOBE trail the authors compared the clinical efficacy of balloon dilatation and stent positioning for treatment of benign tracheal stenosis with a follow-up of 2 years. This study showed that stent placement, with removal 1 year later, had a better effect on long-term stabilisation of tracheal patency, in respect to balloon dilatation technique (5). Based on these data, stent can be considered a temporary device that can support airway remodeling and regeneration of the tracheal cartilages, so, after a variable time, it can be removed in order to asses if airway patency was restored (23,34,63,65). However, the appropriate timing of stent removal is not well defined: Dumon et al. reported a mean duration of stent placement of 1.2 years (longest duration of 6.2 years) (64), Galluccio et al. reported a mean duration of 1.5 years (ranging from 6 months to 3 years), in particular 10±6 months and 20±3 for simple and complex stenoses, respectively (23), while similar period (12 months) was reported by Lim et al. in a study on 55 patients (66). In a recent review, Chen et al. reported that the curative rates of stent positioning were significantly lower in <6-month group in respect to 6–12- and >12-month groups (67). These findings implied that early removal of stent should be avoided to ensure the stability of the stenosis.

Nevertheless, also silicone stents are not free from complications. They include granuloma formation at the proximal or distal ends of the stent, due to insufficient flexibility to conform to irregular airway. In literature it ranges between 9% and 49% (5,64,66,68). Another complication is represented by secretion stasis, that may obstruct the stent, ranging between 3.6% and 41.4% of cases (5,64,66,68). Stent migration may occur in a variable percentage of cases that in literature ranges between 2% and 36% (5,64,66,68). A recent metanalysis from 8 studies on 395 patients, reported a stent migration rate of 25.04% (95% CI: 17.52–35.79%) (67). In order to overcome this complication, some authors proposed external fixation using suture buried subcutaneously (69,70) or with a fixation apparatus (71), however this practice still isn’t a routine.

Regular bronchoscopy follow-up should be conducted after Dumon stenting for early identification and management of related complications.

Strengths and limitations

This paper has some limitations. Firstly, it focus only on benign stenosis that is a rare disease. Secondly, this is a brief and non systematic review that did not require a selection of all eligible literature following predetermined eligibility criteria. However, our aim was to provide an empirical evidence-based review, underling the role of bronchoscopy as a fundamental step in the diagnosis and in the decision making process of choosing the best therapeutic approach.

Conclusions

We want to propose some key messages. Benign stenosis may be an airway emergency, and in some cases, airway patency must be restored emergently via rigid bronchoscopy. Bronchoscopy is recommended before any intervention to assess lesion characteristics that influence the decision regarding endoscopic or surgical management. A multidisciplinary team evaluation, including bronchoscopist and thoracic surgeon, is recommended, in order to guarantee optimal and timely care for patients with tracheal stenosis. Surgical evaluation should be performed, even during emergency bronchoscopy, especially for patients who are known to have a complex stenosis. Additionally, bronchoscopic mechanical dilatation can be considered a valid option for inoperable patients.

We hope this paper will help the bronchoscopist in performing a methodical and precise evaluation of tracheal stenosis and thus in suggesting the appropriate treatment. Moreover, we would promote other clinicians to report their own data on bronchoscopy, as a essential moment for diagnosis and as therapeutic treatment.

Acknowledgments

Funding: None.

Footnote

Reporting Checklist: The authors have completed the Narrative Review reporting checklist. Available at https://jovs.amegroups.com/article/view/10.21037/jovs-24-29/rc

Peer Review File: Available at https://jovs.amegroups.com/article/view/10.21037/jovs-24-29/prf

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jovs.amegroups.com/article/view/10.21037/jovs-24-29/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Helsinki Declaration (as revised in 2013). Written informed consent was obtained from the patient for the publication of this study, the accompanying images, and the videos. A copy of the written consent is available for review by the editorial office of this journal.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

1. Agrawal A, Baird BJ, Madariaga MLL, et al. Multi-disciplinary management of patients with benign airway strictures: A review. Respir Med. 2021;187:106582. [Crossref] [PubMed]
2. Honings J, Gaissert HA, Ruangchira-Urai R, et al. Pathologic characteristics of resected squamous cell carcinoma of the trachea: prognostic factors based on an analysis of 59 cases. Virchows Arch 2009;455:423-9. [Crossref] [PubMed]
3. Catano J, Uzunhan Y, Paule R, et al. Presentation, Diagnosis, and Management of Subglottic and Tracheal Stenosis During Systemic Inflammatory Diseases. Chest 2022;161:257-65. [Crossref] [PubMed]
4. Aravena C, Almeida FA, Mukhopadhyay S, et al. Idiopathic subglottic stenosis: a review. J Thorac Dis 2020;12:1100-11. [Crossref] [PubMed]
5. Marchioni A, Tonelli R, Andreani A, et al. Molecular Mechanisms and Physiological Changes behind Benign Tracheal and Subglottic Stenosis in Adults. Int J Mol Sci 2022;23:2421. [Crossref] [PubMed]
6. Goldenberg D, Ari EG, Golz A, et al. Tracheotomy complications: a retrospective study of 1130 cases. Otolaryngol Head Neck Surg 2000;123:495-500. [Crossref] [PubMed]
7. Cooper JD, Grillo HC. The evolution of tracheal injury due to ventilatory assistance through cuffed tubes: a pathologic study. Ann Surg 1969;169:334-48. [Crossref] [PubMed]
8. Cooper JD. Tracheal Injuries Complicating Prolonged Intubation and Tracheostomy. Thorac Surg Clin 2018;28:139-44. [Crossref] [PubMed]
9. Songu M, Ozkul Y. Risk Factors for Adult Postintubation Tracheal Stenosis. J Craniofac Surg 2019;30:e447-50. [Crossref] [PubMed]
10. Li M, Yiu Y, Merrill T, et al. Risk Factors for Posttracheostomy Tracheal Stenosis. Otolaryngol Head Neck Surg 2018;159:698-704. [Crossref] [PubMed]
11. Gelbard A, Francis DO, Sandulache VC, et al. Causes and consequences of adult laryngotracheal stenosis. Laryngoscope 2015;125:1137-43. [Crossref] [PubMed]
12. Brixey AG, McCallum R. Imaging of Large Airway Disorders. Clin Chest Med 2024;45:489-503. [Crossref] [PubMed]
13. Ratwani AP, Chen H, Brown L, et al. Inter-rater reliability of a novel objective endpoint for benign central airway stenosis interventions: Segmentation-based volume rendering of computed tomography scans. PLoS One 2023;18:e0290393. [Crossref] [PubMed]
14. Arora D, Tewari P, Shamshery C, et al. 3D Virtual Bronchoscopy as an Aid to Airway Management in a Patient with Anterior Mediastinal Mass. Ann Card Anaesth 2024;27:165-8. [Crossref] [PubMed]
15. Cheng LP, Gu Y, Gui XW, et al. Diagnostic Value of Virtual Bronchoscopic Navigation in the Bronchial Tuberculosis Induced Central Airway Stenosis. Infect Dis Ther 2020;9:165-74. [Crossref] [PubMed]
16. Heyer CM, Nuesslein TG, Jung D, et al. Tracheobronchial anomalies and stenoses: detection with low-dose multidetector CT with virtual tracheobronchoscopy--comparison with flexible tracheobronchoscopy. Radiology 2007;242:542-9. [Crossref] [PubMed]
17. McInnis MC, Weisbrod G, Schmidt H. Advanced Technologies for Imaging and Visualization of the Tracheobronchial Tree: From Computed Tomography and MRI to Virtual Endoscopy. Thorac Surg Clin 2018;28:127-37. [Crossref] [PubMed]
18. Myer CM 3rd, O'Connor DM, Cotton RT. Proposed grading system for subglottic stenosis based on endotracheal tube sizes. Ann Otol Rhinol Laryngol 1994;103:319-23. [Crossref] [PubMed]
19. McCaffrey TV. Classification of laryngotracheal stenosis. Laryngoscope 1992;102:1335-40. [Crossref] [PubMed]
20. Brouns M, Jayaraju ST, Lacor C, et al. Tracheal stenosis: a flow dynamics study. J Appl Physiol (1985) 2007;102:1178-84. [Crossref] [PubMed]
21. Murgu S, Colt H. Subjective assessment using still bronchoscopic images misclassifies airway narrowing in laryngotracheal stenosis. Interact Cardiovasc Thorac Surg 2013;16:655-60. [Crossref] [PubMed]
22. Begnaud A, Connett JE, Harwood EM, et al. Measuring central airway obstruction. What do bronchoscopists do? Ann Am Thorac Soc 2015;12:85-90. [Crossref] [PubMed]
23. Galluccio G, Lucantoni G, Battistoni P, et al. Interventional endoscopy in the management of benign tracheal stenoses: definitive treatment at long-term follow-up. Eur J Cardiothorac Surg 2009;35:429-33; discussion 933-4. [Crossref] [PubMed]
24. Bacchin D, Aprile V, Lenzini A, et al. Surgical treatment of tracheal stenosis during Covid-19 era: a single-center experience and lessons learnt on the field. Updates Surg 2023;75:1681-90. [Crossref] [PubMed]
25. Grillo HC, Donahue DM, Mathisen DJ, et al. Postintubation tracheal stenosis. Treatment and results. J Thorac Cardiovasc Surg 1995;109:486-92; discussion 492-3. [Crossref] [PubMed]
26. Rea F, Callegaro D, Loy M, et al. Benign tracheal and laryngotracheal stenosis: surgical treatment and results. Eur J Cardiothorac Surg 2002;22:352-6. [Crossref] [PubMed]
27. Ciccone AM, De Giacomo T, Venuta F, et al. Operative and non-operative treatment of benign subglottic laryngotracheal stenosis. Eur J Cardiothorac Surg 2004;26:818-22. [Crossref] [PubMed]
28. Martinod E, Seguin A, Holder-Espinasse M, et al. Tracheal regeneration following tracheal replacement with an allogenic aorta. Ann Thorac Surg 2005;79:942-9. [Crossref] [PubMed]
29. Menna C, Andreetti C, Ibrahim M, et al. Successful Total Tracheal Replacement by Cryopreserved Aortic Allograft in a Patient Post-COVID-19 Infection. Chest 2021;160:e613-7. [Crossref] [PubMed]
30. Fanucchi O, Picchi A, Marrama E, et al. Multidisciplinary treatment of benign tracheal stenosis—a case report. J Vis Surg 2023;9:37. [Crossref]
31. D'Andrilli A, Maurizi G, Andreetti C, et al. Long-term results of laryngotracheal resection for benign stenosis from a series of 109 consecutive patients. Eur J Cardiothorac Surg 2016;50:105-9. [Crossref] [PubMed]
32. Bibas BJ, Terra RM, Oliveira AL Junior, et al. Predictors for postoperative complications after tracheal resection. Ann Thorac Surg 2014;98:277-82. [Crossref] [PubMed]
33. Puma F, Ragusa M, Avenia N, et al. The role of silicone stents in the treatment of cicatricial tracheal stenoses. J Thorac Cardiovasc Surg 2000;120:1064-9. [Crossref] [PubMed]
34. Cavaliere S, Bezzi M, Toninelli C, et al. Management of post-intubation tracheal stenoses using the endoscopic approach. Monaldi Arch Chest Dis 2007;67:73-80. [PubMed]
35. Mehta AC, Lee FY, Cordasco EM, et al. Concentric tracheal and subglottic stenosis. Management using the Nd-YAG laser for mucosal sparing followed by gentle dilatation. Chest 1993;104:673-7. [Crossref] [PubMed]
36. Dutau H. Airway stenting for benign tracheal stenosis: what is really behind the choice of the stent? Eur J Cardiothorac Surg 2011;40:924-5. [PubMed]
37. Smith ME, Elstad M. Mitomycin C and the endoscopic treatment of laryngotracheal stenosis: are two applications better than one? Laryngoscope 2009;119:272-83. [Crossref] [PubMed]
38. Bertelsen C, Shoffel-Havakuk H, O'Dell K, et al. Serial In-Office Intralesional Steroid Injections in Airway Stenosis. JAMA Otolaryngol Head Neck Surg 2018;144:203-10. [Crossref] [PubMed]
39. Hoffman MR, Coughlin AR, Dailey SH. Serial office-based steroid injections for treatment of idiopathic subglottic stenosis. Laryngoscope 2017;127:2475-81. [Crossref] [PubMed]
40. Cavaliere S, Dumon JF. Laser bronchoscopy. In: Bolliger CT, Mathur PN (eds) Progress in respiratory research — Interventional bronchoscopy. Karger, Cape Town, 2000; pp 108-19.
41. Lee KH, Ko GY, Song HY, et al. Benign tracheobronchial stenoses: long-term clinical experience with balloon dilation. J Vasc Interv Radiol 2002;13:909-14. [Crossref] [PubMed]
42. Khemasuwan D, Mehta AC, Wang KP. Past, present, and future of endobronchial laser photoresection. J Thorac Dis 2015;7:S380-8. [PubMed]
43. Sachdeva A, Pickering EM, Lee HJ. From electrocautery, balloon dilatation, neodymium-doped:yttrium-aluminum-garnet (Nd:YAG) laser to argon plasma coagulation and cryotherapy. J Thorac Dis 2015;7:S363-79. [PubMed]
44. Jako GJ. Laser surgery of the vocal cords. An experimental study with carbon dioxide lasers on dogs. Laryngoscope 1972;82:2204-16. [Crossref] [PubMed]
45. Sagawa M, Inoue K, Sato M, et al. Successful resection of endotracheal papillary adenocarcinoma by endoscopic electrosurgery using a new snare: report of a case. Surg Today 1999;29:570-2. [Crossref] [PubMed]
46. Dumon JF, Reboud E, Garbe L, et al. Treatment of tracheobronchial lesions by laser photoresection. Chest 1982;81:278-84. [Crossref] [PubMed]
47. Park JW, Ko Y, Kim C. Use of an Insulation-Tipped Knife during Rigid Bronchoscopic Treatment of Benign Tracheobronchial Stenosis. Medicina (Kaunas) 2021;57:251. [Crossref] [PubMed]
48. Bo L, Li C, Chen M, et al. Application of Electrocautery Needle Knife Combined with Balloon Dilatation versus Balloon Dilatation in the Treatment of Tracheal Fibrotic Scar Stenosis. Respiration 2018;95:182-7. [Crossref] [PubMed]
49. Yamamoto K, Kojima F, Tomiyama K, et al. Meta-analysis of therapeutic procedures for acquired subglottic stenosis in adults. Ann Thorac Surg 2011;91:1747-53. [Crossref] [PubMed]
50. Taylor SC, Clayburgh DR, Rosenbaum JT, et al. Clinical manifestations and treatment of idiopathic and Wegener granulomatosis-associated subglottic stenosis. JAMA Otolaryngol Head Neck Surg 2013;139:76-81. [Crossref] [PubMed]
51. Wierzbicka M, Tokarski M, Puszczewicz M, et al. The efficacy of submucosal corticosteroid injection and dilatation in subglottic stenosis of different aetiology. J Laryngol Otol 2016;130:674-9. [Crossref] [PubMed]
52. Hoffman GS, Thomas-Golbanov CK, Chan J, et al. Treatment of subglottic stenosis, due to Wegener's granulomatosis, with intralesional corticosteroids and dilation. J Rheumatol 2003;30:1017-21. [PubMed]
53. Penafiel A, Lee P, Hsu A, et al. Topical mitomycin-C for obstructing endobronchial granuloma. Ann Thorac Surg 2006;82:e22-3. [Crossref] [PubMed]
54. Queiroga TLO, Cataneo DC, Martins RHG, et al. Mitomycin C in the Endoscopic Treatment of Laryngotracheal Stenosis: Systematic Review and Proportional Meta-Analysis. Int Arch Otorhinolaryngol 2020;24:e112-24. [Crossref] [PubMed]
55. Roh JL, Kim DH, Rha KS, et al. Benefits and risks of mitomycin use in the traumatized tracheal mucosa. Otolaryngol Head Neck Surg 2007;136:459-63. [Crossref] [PubMed]
56. Makris D, Marquette CH. Tracheobronchial stenting and central airway replacement. Curr Opin Pulm Med 2007;13:278-83. [Crossref] [PubMed]
57. Tsakiridis K, Darwiche K, Visouli AN, et al. Management of complex benign post-tracheostomy tracheal stenosis with bronchoscopic insertion of silicon tracheal stents, in patients with failed or contraindicated surgical reconstruction of trachea. J Thorac Dis 2012;4:32-40. [PubMed]
58. Wood DE, Liu YH, Vallières E, et al. Airway stenting for malignant and benign tracheobronchial stenosis. Ann Thorac Surg 2003;76:167-72; discussion 173-4. [Crossref] [PubMed]
59. Takigawa Y, Sato K, Kudo K, et al. Successful treatment of tracheal stenosis due to a broken uncovered metallic stent placed over 20 years ago in a patient with recurrent polychondritis using argon plasma coagulation and airway ballooning. Respirol Case Rep 2024;12:e70034. [Crossref] [PubMed]
60. Rodriguez AN, Díaz-Jiménez JP, Edell ES. Silicone stents versus metal stents for management of benign tracheobronchial disease con: metal stents. Journal of Bronchology & Interventional Pulmonology 2000;7:184-7.
61. Gildea TR, Murthy SC, Sahoo D, et al. Performance of a self-expanding silicone stent in palliation of benign airway conditions. Chest 2006;130:1419-23. [Crossref] [PubMed]
62. FDA Public Health Notification: Complications from Metallic Tracheal Stents in Patients with Benign Airway Disorders. 2005. Available online: https://www.jsre.org/uploads/files/info/0801_fda.pdf
63. Foccoli P, Scappaticci E, Rea F, et al. Management of post-intubation and/or tracheotomy tracheal stenoses. Monaldi Arch Chest Dis 2011;75:82-5. [PubMed]
64. Dumon J, Cavaliere S, Díaz-Jiménez JP, et al. Seven-Year Experience with the Dumon Prosthesis. Journal of Bronchology 1996;3:6-10. [Crossref]
65. Mandour M, Remacle M, Van de Heyning P, et al. Chronic subglottic and tracheal stenosis: endoscopic management vs. surgical reconstruction. Eur Arch Otorhinolaryngol 2003;260:374-80. [Crossref] [PubMed]
66. Lim SY, Kim H, Jeon K, et al. Prognostic factors for endotracheal silicone stenting in the management of inoperable post-intubation tracheal stenosis. Yonsei Med J 2012;53:565-70. [Crossref] [PubMed]
67. Chen DF, Chen Y, Zhong CH, et al. Long-term efficacy and safety of the Dumon stent for benign tracheal stenosis: a meta-analysis. J Thorac Dis 2021;13:82-91. [Crossref] [PubMed]
68. Shin B, Kim K, Jeong BH, et al. Clinical implications of differentiating between types of post-tracheostomy tracheal stenosis. J Thorac Dis 2017;9:4413-23. [Crossref] [PubMed]
69. Andreetti C, Menna C, D'Andrilli A, et al. A modified technique to simplify external fixation of the subglottic silicone stent. Interact Cardiovasc Thorac Surg 2018;27:878-80. [Crossref] [PubMed]
70. Charous SJ, Westfall E. The suction-assisted endoscopic suture technique: A simple method for endotracheal suturing. Laryngoscope 2020;130:E346-8. [Crossref] [PubMed]
71. Miwa K, Takamori S, Hayashi A, et al. Fixation of silicone stents in the subglottic trachea: preventing stent migration using a fixation apparatus. Ann Thorac Surg 2004;78:2188-90. [Crossref] [PubMed]