Benign Airway Stenosis Research Articles

Possibilities of endoscopic adjuvant use of Mitomycin-S in the treatment of benign airway stenoses

Mitomycin-c is an effective and safe drug in the treatment of benign stenosis of the respiratory tract, to a greater extent increasing the duration of the relapse-free period, the interval between endoscopic manipulations. Due to the lack of clear ideas about the optimal method of administration of the drug, the timing, duration of the application / injection, it is necessary to continue further research.

A Clinical Study on Video Bronchoscopy-guided Coblation for Benign Central Airway Stenosis.

Background: Benign central airway stenosis poses a significant challenge to respiratory and thoracic surgeons due to the high recurrence rate associated with current treatment methods, causing severe breathing difficulties and potentially life-threatening complications. This article aims to investigate the therapeutic efficacy and prospects of using coblation in the management of benign central airway stenosis in adults. Moreover, the pathogenesis of benign central airway stenosis was deeply explored to provide better guidance for future clinical treatments. Materials and Methods: This retrospective study examined patients with benign central airway stenosis who were treated at The Second Hospital of Hebei Medical University from 2017 to 2020. In addition, a comparative analysis of whole-genome sequencing was conducted between the aforementioned patient group and healthy populations to investigate the underlying etiology of this stenotic condition. Results: The present study encompassed 32 patients who underwent 43 treatments in total between 2017 and 2020. All patients exhibited alleviation of airway stenosis and an improvement in clinical symptoms following surgery, without any significant surgical or postoperative complications. Whole-genome analysis revealed significant changes in gene expression in the airway mucosa of patients with benign airway stenosis in comparison to healthy populations. A total of 91 differentially expressed genes were identified, among which 44 upregulated genes displayed characteristics of promoting inflammatory responses. Conclusion: Coblation demonstrates promise as an efficacious treatment modality for adults suffering from benign central airway stenosis, and its widespread application in clinical settings is anticipated. The direct pathogenesis of benign central airway stenosis involves airway lumen narrowing and obstruction resulting from excessive inflammation and proliferative granulation.

MiR-34c-5p inhibited fibroblast proliferation, differentiation and epithelial-mesenchymal transition in benign airway stenosis via MDMX/p53 pathway

Benign airway stenosis (BAS) means airway stenosis or obstruction that results from a variety of non-malignant factors, including tuberculosis, trauma, benign tumors, etc. In consideration of the currently limited research on microRNAs in BAS, this study aimed to explore the role and mechanism of miR-34c-5p in BAS. The expression of miR-34c-5p in BAS granulation tissues showed a significant down-regulation compared with the normal control group. Moreover, miR-34c-5p mimics suppressed the proliferation and differentiation of human bronchial fibroblasts (HBFs) and the epithelial-mesenchymal transition (EMT) of human bronchial epithelial cells (HBE). Conversely, miR-34c-5p inhibitors aggravated those effects. A dual-luciferase reporter assay confirmed that miR-34c-5p can target MDMX rather than Notch1. The over-expression of MDMX can reverse the inhibiting effect of miR-34c-5p on HBFs proliferation, differentiation and EMT. Furthermore, the expressions of tumor protein (p53) and PTEN were down-regulated following the over-expression of MDMX. In addition, the expressions of PI3K and AKT showed an up-regulation. In conclusion, miR-34c-5p was down-regulated in BAS and may inhibit fibroblast proliferation differentiation and EMT in BAS via the MDMX/p53 signaling axis. These findings expand the understanding of the role of miR-34c-5p and will help develop new treatment strategies for BAS.

The Wound Healing of Autologous Regenerative Factor on Recurrent Benign Airway Stenosis: A Canine Experimental and Pilot Study

Introduction: Benign airway stenosis (BAS) is a severe pathologic condition. Complex stenosis has a high recurrence rate and requires repeated bronchoscopic interventions for achieving optimal control, leading to recurrent BAS (RBAS) due to intraluminal granulation. Methods: This study explored the potential of autologous regenerative factor (ARF) for treating RBAS using a post-intubation tracheal stenosis canine model. Bronchoscopic follow-ups were conducted, and RNA-seq analysis of airway tissue was performed. A clinical study was also initiated involving 17 patients with recurrent airway stenosis. Results: In the animal model, ARF demonstrated significant effectiveness in preventing further collapse of the injured airway, maintaining airway patency and promoting tissue regeneration. RNA-seq results showed differential gene expression, signifying alterations in cellular components and signaling pathways. The clinical study found that ARF treatment was well-tolerated by patients with no severe adverse events requiring hospitalization. ARF treatment yielded a high response rate, especially for post-intubation tracheal stenosis and idiopathic tracheal stenosis patients. Conclusion: The study concludes that ARF presents a promising, effective, and less-invasive method for treating RBAS. ARF has shown potential in prolonging the intermittent period and reducing treatment failure in patients with recurrent tracheal stenosis by facilitating tracheal mucosal wound repair and ameliorating tracheal fibrosis. This novel approach could significantly impact future clinical applications.

Clinical Analysis of 32 Cases of Subglottic Benign Airway Stenosis Treated With Montgomery T Silicone Stent.

Objective: To explore the complications of long-term placement of Montgomery T silicone stent (T-tube) in the treatment of subglottic benign airway stenosis (SBAS) and the timing of successful T-tube removal. Methods: We retrospectively collected the clinical data of 32 patients with SBAS who underwent the treatment of T-tube and analyzed their placement and successful removal of the T-tube. Results: There were 22 males and 10 females, aged from 21 to 79 years (60.9 ± 13.7 years). The T-tubes were successfully placed in all 32 patients, and 6 patients (18.8%) with mild stenosis were placed by the intravenous conscious sedation. The longest follow-up period was 60.4 months, and 17 patients (53.1%) had the T-tubes for more than 12 months; 5 patients (15.6%) were changed to the tracheostomy cannula after unplanned removal of the T-tubes for various reasons; the T-tubes were successfully removed in 9 patients (28.1%), and the duration of T-tubes placement was 5.2-22.7 months (12.1 ± 6.3 months), among them anatomical stenosis in 9 patients (100%). Secretion retention was observed in 32 patients (100%), granulation tissue hyperplasia was observed in 9 patients (28.1%), and the normal ventilation was not affected in most patients by bronchoscopic treatment and follow-up; the T-tubes were removed in 3 patients due to severe complications. There was no significant difference in the incidences of secretion retention and granulation tissue hyperplasia between the time point at 1 week, 1 month, 3 months, and 12 months, p > 0.05. In patients with T-tube more than 12 months, the severity of secretion retention at 1 week, 1 month, 3 months, and 12 months was significantly different, p < 0.05, however, there was no significant difference in the severity of granulation tissue hyperplasia, p > 0.05. Conclusions: T-tube is safe and effective in the treatment of SBAS. The severity of secretion retention increased in patients with long-term placement of the T-tube. For patients with mild stenosis and anatomical stenosis, the T-tube removal can be attempted at about 1 year of follow-up.

Study on the effect and mechanism of verapamil on the growth of human airway granulosa fibroblasts

Objective: This study aimed to investigate the inhibitory effect of the calcium channel blocker verapamil on human airway sarcomeric fibroblasts through network pharmacology molecular docking combined with experimental validation, so as to provide a theoretical and experimental basis for clinical use of calcium channel blockers against benign airway stenosis. Methods: The relevant targets of verapamil, airway injury, sarcoidosis and fibroblast were collected and intersected by a public database, respectively. The protein-protein interaction network was constructed by combining STRING; the DAVID database was used for gene function GO and KEGG pathway enrichment analysis. Molecular docking validation of verapamil and key targets was performed using AutoDock. Meanwhile, human lung bronchial tissue and human airway granulation tissue were treated with different antibiotic regimens to prevent contamination, in which human normal airway fibroblasts were treated with 92.81 μg/ml verapamil, while airway granulosa fibroblasts were treated with 69.57 μg/ml verapamil. The flow cytometry test was performed to detect the apoptotic effect of verapamil on human airway granulosa fibroblasts. The relative expression of mRNA of relevant factors between human normal airway fibroblasts and human airway granulosa fibroblasts was detected using polymerase chain reaction (PCR). Meanwhile, the difference in mRNA expression between human airway fibroblasts in normal and disease conditions was measured by PCR, and the change in mRNA expression of related factors after treatment with verapamil was determined to verify the findings of network pharmacology analysis. Results: This study predicted that verapamil affects 162 targets in human airway granulosa fibroblasts, among which, the most concerned and core target proteins are TGF-β1, VEGFA and IL-6; mainly involved in biological processes such as apoptosis, angiogenesis, energy metabolism and inflammation, and AGE-RAGE, JAK-STAT, PI3K-AKT, HIF as well as IL-17 signaling pathways. Molecular docking results showed that verapamil can bind to key targets. The apoptosis rate of human airway granulomatous fibroblasts treated with verapamil was higher than that of the control group, and the difference was statistically significant (P &lt; 0.05). PCR showed that the relative expression of TGF-β1, VEGFA, IL-6 and other mRNAs in human airway granulomatous fibroblasts was significantly higher than that in human normal airway fibroblasts (P &lt; 0.05), whereas the relative expression of TGF-β1 mRNA was down-regulated (P &lt; 0.05) and the mRNA expression of VEGFA, IL-6 did not change significantly (P &gt; 0.05) in human airway granulosa fibroblasts after treatment with verapamil. Conclusions: Increasing the antibiotic concentration and combining multiple antibiotics to soak the tissue can effectively kill the tissue pathogens. Verapamil can inhibit the proliferation of airway granulomatous fibroblasts through multiple targets and pathways, and it may be a method to prevent and treat benign airway stenosis.

Analysis of clinical characteristics of 617 patients with benign airway stenosis.

Benign airway stenosis (BAS), namely airway narrowing caused by a variety of benign lesions, can lead to varying degrees of breathing difficulties and even death due to asphyxia. This study aimed to elucidate the clinical characteristics of BAS, including etiology, treatment and pathology, by analyzing the clinical data of BAS patients. A retrospective analysis was conducted using the clinical data of 617 BAS cases from January 2017 to December 2022. The pathological characteristics of the tissues were assessed by hematoxylin-eosin (H&E) and Masson's staining. Besides, protein expression levels were determined by immunohistochemistry (IHC). A total of 617 patients were included (333 females [53.97%] and 284 males [46.03%]), with an average age of 48.93 ± 18.30 (range 14-87). Tuberculosis (n = 306, 49.59%) and trauma (n = 179, 29.02%) were the two leading etiologies of BAS, followed by airway foreign bodies (FB, n = 74, 11.99%), external compression (n = 25, 4.05%) and other etiologies (n = 33, 5.35%). Among 306 tuberculous tracheobronchial stenosis (TBTS) cases, most were females (n = 215, 70.26%), and TBTS mainly occurred in the left main bronchus (n = 97, 31.70%), followed by the right middle bronchus (n = 70 cases, 22.88%). The majority of TBTS patients (n = 259, 84.64%) were treated by interventional therapy. The condition of 179 BAS patients was ascribed to trauma, such as tracheal intubation (n = 92, 51.40%), tracheotomy (n = 69, 38.56%), injury (n = 15, 8.38%) and surgery (n = 3, 1.68%), which mostly took place in the trachea (n = 173, 96.65%). TAS patients mainly received interventional therapy (n = 168, 93.85%) and stent implantation (n = 47, 26.26%). The granulation tissues of BAS primarily featured inflammation, proliferation and fibrosis. IHC indicated the up-regulated expressions of transforming growth factor-β1 (TGF-β1), α-smooth muscle actin (α-SMA), collagen type I protein (COL-I) and vimentin, and the down-regulated expression of E-cadherin, which indicated fibrosis and epithelial-mesenchymal transition (EMT). Tuberculosis was the main etiology, and trauma was the secondary etiology. The granulation tissues of BAS were characterized by inflammation, fibrosis and probably EMT. Comprehensive interventional therapy is an effective method of treating BAS.

Endoscopic Management of Benign Airway Stenosis in Coronavirus Disease 2019 Patients.

The aims of this study were to evaluate the results of endoscopic dilation for simple benign airway stenosis in coronavirus disease 2019 (COVID-19) patients and whether COVID-19 infection was associated with higher rate of recurrence compared with a control group. It was an observational multicenter study including consecutive patients with simple benign airway stenosis undergoing endoscopic dilatation with at least 6 months of follow-up. The outcome of patients with COVID-19 infection was compared with that of a control group in relation to patient and stenosis characteristics, and procedure type. Then, univariable and multivariable analyses identified the risk factors for recurrence. Seventy-nine patients were included in the study; 56 (71%) of these developed airway stenosis after COVID-19 infection. COVID-19 patients presented a higher rate of stenosis due to prolonged intubation (82 vs. 43%; p = 0.0014); no other differences were found regarding demographic data, characteristics of stenosis, and procedure type. Twenty-four (30%) patients had recurrence after first dilatation (32% for No-COVID-19 vs. 26% for COVID-19 group; p = 0.70), and in 11 (35%) of these, the stenosis recurred after repeated endoscopic treatment (65% for No-COVID-19 vs. 45% for COVID-19 group; p = 0.40). Subglottic stenosis (p = 0.013) and the use of laser (p = 0.016) were significant predictive factors for stenosis recurrence. COVID-19 infection did not affect the outcome of endoscopic treatment of simple airway stenosis, and the treatment of these subsets of patients should not differ from that of general population.

Rigid Bronchoscopy for Post-Tuberculosis Tracheobronchial Stenosis.

The healing process of tracheobronchial tuberculosis (TB) result in tracheobronchial fibrosis causing airway stenosis in 11-42% of patients. In Korea, where pulmonary TB is still prevalent, post-TB tracheobronchial stenosis (PTTS) is one of the main causes of benign airway stenosis causing progressive dyspnea, hypoxemia and often representing life-threatening respiratory insufficiency. The development of rigid bronchoscopy replaced surgical management since last 30 years, and nowadays PTTS is mainly managed by bronchoscopic intervention in Korea. When diagnosed, tracheobronchial TB is treated by combination of anti-TB medications as other pulmonary TB. The indication of rigid bronchoscopy is more than ATS grade 3 dyspnea in PTTS patients. At first narrowed airway is dilated by multiple techniques, including ballooning, laser resection, bougienation under general anesthesia. Then, most of patients need silicone stenting to maintain the patency of dilated airway. 1.5~2 years after indwelling, the stent could be removed with 70% of success rate. Acute complications develops in less than 10% of patients without mortality. Subgroup analysis showed successful removal of stent was significantly associated with male sex, young age, good baseline lung function and absence of complete one lobe collapse. In conclusion, rigid bronchoscopy could be applied to PTTS patients with acceptable efficacy and tolerable safety.

Inhibitory Effect of Verapamil on the Growth of Human Airway Granulation Fibroblasts.

To explore the inhibitory effect of verapamil, a calcium channel blocker, on the growth of human airway granulation fibroblasts to provide an experimental basis for the clinical use of calcium channel blockers in preventing and treating benign airway stenosis. Primary human airway normal fibroblasts and human airway granulation fibroblasts were cultured by tissue block attachment culture method, and the experimental studies were carried out using 3-8 generation cells. Cell Counting Kit-8 (CCK-8) was used to test the proliferation of human normal airway fibroblasts and human airway granulation fibroblasts and the semi-inhibitory concentration of verapamil on normal airway fibroblasts and airway granulation fibroblasts. A scratch test detected the migration effect of verapamil on human airway granulation fibroblasts. The mRNA relative expression levels of related factors were detected by PCR to compare the differences between normal airway fibroblasts and airway granulation fibroblasts. Western blot was used to detect the relative amount of related proteins and compare the differences between normal airway fibroblasts and granulation airway fibroblasts. After 48 hours of treatment with half of the inhibitory concentration of Vera Pammy for granulation airway fibroblasts, the relative expression levels of related factors on mRNA and protein were observed. Human normal airway fibroblasts and human airway granulation fibroblasts with a purity of more than 95% could be obtained from primary culture by tissue block adherence method. CCK8 results showed that the proliferation rate of human airway granulation fibroblasts was faster than that of the normal human airway fibroblasts. The semi-inhibitory concentration of verapamil on human normal airway fibroblasts was 92.81 ug/ml, while the semi-inhibitory concentration on human airway granulation fibroblasts was 69.57 ug/ml. The scratch test indicated that the cell migration rate of human airway granulation fibroblasts treated with verapamil decreased significantly (P < 0.05). PCR results showed that the mRNA relative expression levels of TGFβ1, COL1A1, Smad2/3, VEGFA, IL6, and IL8 in human airway granulation fibroblasts were significantly higher than those in normal human airway fibroblasts (P < 0.05). The mRNA relative expressions of TGFβ1, smad2/3, and COL1A1 in human airway granulation fibroblasts treated with semi-inhibited verapamil for 48h were down-regulated (P < 0.05), while the mRNA relative expressions of VEGFA, IL6 and IL8 had no significant changes (P > 0.05). WB test showed that the relative protein expressions of TGFβ1, Smad2, and VEGFC in human airway granulation fibroblasts were upregulated (P < 0.05) but downregulated after verapamil treatment compared with before treatment (P < 0.05). Calcium channel blockers can inhibit the proliferation of human airway granulation fibroblasts through TGFβ1/ Smad pathway, which may be a method to prevent and treat benign airway stenosis.

The role of tracheal wall injury in the development of benign airway stenosis in rabbits

To investigate the role of tracheal wall injury in the development of benign airway stenosis in rabbits. Prospective study. We injured the tracheal walls of 28 New Zealand white rabbits using four different methods. Experimental group: Group A (n = 7, mild injury of tracheal mucosa by ordinary brush under bronchoscopy); Group B (n = 7, severe injury of tracheal mucosa by nylon brush under tracheotomy); Group C (n = 7, tracheal cartilage was injured by vascular clamp after tracheotomy); Group D (n = 7, the tracheal cartilage was injured with vascular forceps and the tracheal mucosa was injured with a nylon brush after tracheotomy). Bronchoscopy was performed on each experimental rabbit at 1, 2, 3 and 4 weeks after operation. High-resolution computed tomography (HRCT) and endobronchial optical coherence tomography (EB-OCT) were performed at 4 weeks, and the rabbits were sacrificed after the examination. Their gross and histological findings were comparatively determined whether the experimental rabbit stenosis was established. No airway stenosis was observed in group A. In group B, 28.57% of experimental rabbits developed tracheal stenosis (granulation tissue proliferation was observed in rabbits No. 2 and No. 6 at 1, 2 and 3 weeks after operation, and the tracheal scar contracture was observed in No.6 rabbit at 4 weeks after operation). Fourteen rabbits in group C and group D had tracheal stenosis caused by granulation tissue proliferation at 1, 2 and 3 weeks after operation. At the fourth week after operation, 71.43% of experimental rabbits had tracheal stenosis due to granulation tissue hyperplasia, 7.14% of experimental rabbits had tracheal stenosis due to scar contracture and granulation hyperplasia, and 21.43% of experimental rabbits had tracheal stenosis due to scar contracture. EB-OCT scan showed that the cartilage layer with low signal reflection band was discontinuous. The injury of cartilage is the key factor of benign airway stenosis. Acute injury of airway mucosa alone is unlikely to cause airway stenosis, but combined with cartilage injury may aggravate airway stenosis. EB-OCT can clearly identify the airway layers of rabbits, which is helpful to evaluate the damage of tracheal cartilage and mucosa. The diagnostic potential of this technique makes EB-OCT a promising approach for the study and monitoring of airway diseases.

Long-term efficacy and safety of the Dumon stent for treatment of benign airway stenosis.

The long-term efficacy of the Dumon stent in the treatment of benign airway stenosis is unclear. The objective of this study was to evaluate the long-term efficacy and safety of the Dumon stent in patients with benign airway stenosis. We retrospectively reviewed patients with benign airway stenosis who were treated with a Dumon stent at the First Affiliated Hospital of Guangzhou Medical University between March 2014 and October 2021. We included patients with successful removal of silicone stents after implantation. The clinical data and information on bronchoscopic interventional procedures and related complications were collected and analyzed. Ninety-nine patients with benign airway stenosis were included. The stent was placed mainly in the trachea (44.4%) and left main bronchus (43.4%). The main type of stenosis was post-tuberculosis bronchial stenosis (57.6%). The overall cure rate was 60.6%. Stent-related complications included retention of secretions (70.7%), granuloma formation (67.7%), stent angulation (21.2%), and stent migration (12.1%). The stent was less effective for left main bronchus stenosis (p = 0.012). Multivariate logistic regression analysis identified that stent placement for more than 13 months, a stent-intervention number of ⩽ 1 predicted a favorable outcome. The efficacy and safety of the Dumon stent for benign airway stenosis need improvement. The stent is less effective for left main bronchus stenosis; regular follow-up is required in such cases. Stent placement for > 13 months and no more than once stent intervention within a 6-month period were associated with a favorable outcome.

Relationship between etiology and morphological classification of benign central airway stenosis and its prognosis

Objectives: To analyze the relationship between etiology and morphological classification of benign central airway stenosis and its prognosis. Methods: We performed a retrospective study of the medical records of 453 patients initially diagnosed with benign airway stenosis at Department of Respiratory Diseases in Beijing Tiantan Hospital affiliated to Capital Medical University from January 2003 to October 2019. Of 453 patients, 260 were male. The age of the study population was 12-86(44.0±24.5) years. Results: Among the 453 patients diagnosed with benign central airway stenosis, 161 case (35.5%, including 113 post-tracheostomy tracheal stenosis and 48 post-intubation tracheal stenosis) were iatrogenic; 88 cases were from benign tumors (19.4%), 77 cases from tracheal or bronchial tuberculosis (17.0%), 71 case from tracheal foreign bodies (15.7%). Disease causes varied among different gender or age groups. The main type of stenosis was structural stenosis, of which 241 cases (53.2%) were intra-luminal and 183 cases (40.4%) were scar contracture type. The site of stenosis showed a certain relationship with the causes of stenosis. The stenosis degree was mainly from grade 2 to grade 4 (76.4%), and the length was mainly within 3 cm (84.8%). Single factor analysis on the relationship between disease cause, morphological classification and prognosis of benign central airway stenosis showed statistically better prognosis in groups that were caused by benign tumor, intraductal stenosis or stenosis that were 3-4 in degree and 1-2 degree in length. Conclusion: The common causes of central airway stenosis included iatrogenic stenosis, benign tumor, tracheal or bronchial tuberculosis and tracheal foreign bodies. Benign airway stenosis with different disease causes and morphological classification had different prognosis after bronchoscopic interventional treatment. Clinicians should know the disease causes, morphological characterization and risk factors for benign airway stenosis for earlier diagnosis, treatment or prevention.

Establishment of two canine models of benign airway stenosis and the effect of mitomycin C on airway stenosis

ObjectivesCuffed endotracheal intubation and stent implantation were employed to simulate two types of benign airway stenosis and further to analysis the different features between them from trachecscopic characteristics, gross anatomy to histopathological changes. In addition, our study explored the therapeutic effect of mitomycin C at different concentrations on granulation tissue caused by stent implantation in order to provide a new therapeutic strategy for clinical treatment of benign airway stenosis. MethodsTwelve beagle dogs were randomly divided into four groups, with three dogs in each group. Group A: Three beagle dogs were intubated through oral trachea after general anesthesia and cuff pressure maintained at 200 mmHg for 24 h. Group B, Group C and Group D: endotracheal coated self-expanding metal stents were placed after general anesthesia under the guidance of bronchoscope. On the Day7 after stent implantation, Group B, as control group, was injected phosphate buffer solution of 1 ml into granulation tissue at the end of stent; Group C was injected mitomycin C of 1 ml at 0.4 mg/ml and Group D was injected mitomycin C of 1 ml at 0.8 mg/ml into granulation tissue at the end of metal airway stent respectively, the same method as Group B. Bronchoscopy was used to observe tracheal lumen on the seventh day, fourteenth day and twenty-first day after modeling and pathological changes were examined on twenty-first day. ResultsTwo models of benign airway stenosis can be established by cuffed endotracheal intubation and stent implantation. There was tracheal rupture in the trachea cartiage ring in the cuffed endotracheal intubation group, but was't in stent implantation group. Histopathological characteristics were different between cuffed endotracheal intubation and stent implantation groups. In stent placement groups, we found that the stenosis degree of mitomycin C at 0.4 mg/ml was approximately 19%–32%, mitomycin C at 0.8 mg/ml was approximately 16%–21% and the control group was approximately 36%–47%. ConclusionThe two models of canine benign tracheal stenosis induced by cuffed endotracheal intubation and stent implantation are relatively simple, reliable and reproducible and have different characteristics. Mitomycin C could inhibit proliferation of granulation tissue and attenuate the degree of airway stenosis caused by stent implantation.

Paclitaxel-Loaded PLGA Coating Stents in the Treatment of Benign Cicatrical Airway Stenosis

Background: Airway stent implantation used in the treatment of benign cicatricial airway stenosis (BCAS) can lead to local granulation and scar formation, resulting in restenosis and treatment failure. Methods: We systematically investigated a paclitaxel-loaded PLGA-coating stent (PLPCS) and analyzed the safety and efficacy of the PLPCS in patients with BCAS. Patients were enrolled from four hospitals in China and observed for six months after implantation, by bronchoscopy performed weekly in the first month and monthly thereafter. The stent was removed immediately upon detection of granulation tissue proliferation, leading to immobility of the stent. Results: Granulation tissue was formed one week after stent implantation, most of which was located at the upper edge of the stent and the narrowest airway in the stent. All stents were removed in three months (mean: 6.51 + 4.67 weeks), with a curative outcome in one case and ineffective results in two. The remaining seven patients developed complications within three months, necessitating early stent removal. The main complication was granulation formation, resulting in difficulty in stent removal. Conclusion: Although PLPCS showed beneficial effects in basic and animal experiments, it cannot prevent airway restenosis in actual practice, mainly due to granulation formation.

Airway stenting in patients with complex benign tracheobronchial stenosis

Tracheal and bronchial stenting is actively used for cancer and benign airway stenosis. This procedure is common in patients with advanced cancer. Stenting ensures breathing and availability of early chemo- and radiotherapy without the need for tracheostomy. This procedure is less common in patients with benign tracheal stenosis. In this case, isolated tracheal or bronchial stenting is performed. Complex tracheobronchial stenosis is extremely rare and creates significant difficulties. We present 3 cases of tracheobronchial stenting for cicatricial stenosis. In each case, stenosis was dilated with a rigid bronchoscope or balloon dilatation. Then, a silicone stent was installed. Resection with an appropriate anastomosis was contraindicated due to advanced pathological process. Thus stenting was regarded as a palliative operation. The follow-up periods were 9 months, 3 and 10 years. Each patient underwent inhalation therapy, endoscopy and repeated stenting if necessary.

A Rare Case Report Of Benign Airway Stenosis and Challenges in its Management.

Laryngeal stenosis following surgical intervention of larynx is a difficult condition to manage. The extensive adhesions formed between the vocal cords can obstruct the glottis and subglottis region and make decannulation unfeasible. In this report, we describe the challenges faced in the management of Glottosubglotic stenosis formed post Coblation assisted surgery for bilateral abductor cord palsy. The authors emphasize on the prevention techniques and management of laryngeal stenosis with a successful decannulation in such patients.

Impact of gastroesophageal reflux in the pathogenesis of tracheal stenosis.

Benign airway stenosis is a multifactorial and heterogeneous disease often occurring after tracheal intubation. Despite the frequent finding of pathological gastroesophageal reflux (GER) in benign tracheal stenosis, the cause-and-effect relationship between these two entities and its impact on the outcome of the stenosis itself have not been established. The altered ventilatory dynamics caused by an increased thoracoabdominal pressure gradient in such patients has been proposed as a central cause. The presence of GER in a setting of microaspiration can also induce changes in the local collagen proliferation response, as well as in the local microbiome of the tracheal stenosis site, which may potentially cause and enhance the harm imposed to the already diseased tracheal wall. Diagnosis of GER remains underestimated in the general population, thus making its accurate detection and treatment in central airway stenosis a matter of investigation. The high prevalence of GER in tracheal stenosis patients often occurs in the absence of typical upper digestive signs and symptoms, therefore requiring an objective assessment using a 24-hour ambulatory esophageal pH/impedance study that has shown abnormal results in more than half the patients. The impact of the treatment of GER in patients with benign tracheal has been scarcely reported. Our group showed recently that the surgical control of GER through laparoscopic fundoplication in selected patients with tracheal stenosis can improve substantially the chance of resolution of the tracheal stenosis as opposed to the medical management with high dose proton pump inhibitors. This chapter describes the impact of GER in the pathogenesis of tracheal stenosis with a focus on its mechanisms, diagnosis and treatment strategy.

The use of 3D printing model as tool for planning endoscopic treatment of benign airway stenosis.

Benign tracheal stenosis is a life-threatening condition that needs a prompt treatment when the tracheal lumen is less than 5 mm. In patients unfit for surgery, endoscopic dilation with stent insertion (if indicated) remains the main alternative to restore airway patency and assure ventilation. Endoscopic management of tracheal stenosis may be a cumbersome procedure, that sometimes takes a long time, and may be complicated by stent dislocation especially in cases of complex stenosis, near to vocal folds. In recent years, the 3D printing industry has undergone rapid development, and 3D printing model has been increasingly applied to different medical fields where therapeutic interventions rely on defining complex anatomic structural relationships. Thus, in this review we aimed to evaluate whether the use of 3D printing model as tool for preoperative planning could facilitate the endoscopic treatment of tracheal stenosis and improve outcome. Three papers evaluated this issue: one paper reported a consecutive series of patients while the remaining single case report. All authors concluded that the 3D model aided the understanding of patient’s anatomy and the stenosis’s characteristic. The possibility of recreating the endoscopic procedure in the 3D model facilitated and shorted the procedural time in live patient. Furthermore, the 3D model was additionally useful to choose the length, diameter and shape of stent and to define the exact distance of the proximal end of stent from the vocal folds after its insertion. Finally, it represented an educational tool for patients and his/her family to understand the procedure, and for residents and fellows to improve endoscopic skills.

What have we learned in interventional pulmonology in the past decade?

Background/aimThe increasing number of lung diseases and particularly pulmonary malignancies has intensified the need for diverse interventions in the field of interventional pulmonology. In recent years we have seen many new developments and expanding applications in the field of interventional pulmonology. This has resulted in an increased number and variety of performed procedures and differing approaches. The purpose of the present study is to provide information on patient characteristics, range of interventions, complication rates, and the evolving approach of an experienced center for interventional pulmonology.Materials and methodsWe retrospectively examined the records of 1307 patients who underwent a total of 2029 interventional procedures in our interventional pulmonology department between January 2008 and December 2017.ResultsAbout half of the interventional procedures (47.2%) were performed on patients with airway stenosis due to malignant disease. Among patients with benign airway stenosis, the most frequent reason for intervention was postintubation tracheal stenosis. The number of patients who developed complications was 81 (6.2%), and the most common complication was hemorrhage (n = 31, 2.99%); 94.9% (n = 1240) of interventional procedures were performed under general anesthesia, without complications or deaths associated with anesthesia. Only one death (0.076%) occurred in the perioperative period. A total of 18 patients (1.38%) died in the 30-day perioperative and postoperative period. None of the patients with benign airway stenosis died.ConclusionInterventional bronchoscopy is an invasive but considerably safe and efficient procedure for selected cases and effective treatment modality for airway obstructions, massive hemoptysis, and foreign body aspiration. Interventional pulmonology is a field of pulmonary medicine that needs effort to progress and provide an opportunity to witness relevant developments, and increase the number of competent physicians and centers.