Robot-Assisted Correction of a Supra-Long Tracheal Stenosis Using C-Type Nickel-Titanium Alloy Exterior Stenting and Suspension Fixation Technique: A Case Report.

T-tubes and airway stents are commonly used but have limited effectiveness and frequent complications. A 50-year-old male patient presented with severe tracheal stenosis, affecting an 8.7 cm length of the airway. We employed an innovative approach known as external suspension fixation of tracheal stent using robotic assistance. This method involves surgically attaching the stent to the exterior of the trachea to provide support and stabilize the softened or collapsed tracheal segments. We designed a C-shaped nickel-titanium alloy exterior stent and successfully fixed it using robotic assistance. This intervention effectively restored tracheal function and led to a favorable postoperative recovery. The technique does not affect tracheal membrane function or airway mucociliary clearance. It could potentially be considered as a new option for treating long-segment benign tracheal softening or collapse.

Impact of preoperative respiratory distress on outcomes of slide tracheoplasty.

OBJECTIVES: Children with congenital tracheal stenosis born in the developing world face a high risk of mortality due to limited access to proper treatment. Patients who required preoperative respiratory support were suspected to have poor survival after slide tracheoplasty; however, this was not clearly demonstrated in the previous studies. This study aims to investigate the impact of preoperative respiratory conditions on outcomes of slide tracheoplasty. METHODS: From 2016 to 2022, children who underwent slide tracheoplasty were retrospectively reviewed. Patients with respiratory distress requiring emergency operations (group A) were compared with patients in stable condition who were scheduled for surgery (group B). RESULTS: Perioperative results revealed that group A (n = 43) had a longer bypass time (P < 0.001), operation time (P = 0.01), postoperative ventilation time (P < 0.001) and length of intensive care unit stay (P = 0.00125) than group B (n = 60). The early mortality rate was 7.8%, and the actuarial 5-year survival rate was 85.3%. The cumulative incidence test revealed that group A was highly significant for overall mortality [sudistribution (SHR) 4.5; 95% confidence interval (CI) 1.23-16.4; P = 0.023]. Risk factors for overall mortality were prolonged postoperative ventilation time (hazard ratio 3.86; 95% CI 1.20-12.48; P = 0.024), bronchial stenosis (hazard ratio 5.77; 95% CI 1.72-19.31; P = 0.004), and preoperative tracheal mucositis (hazard ratio 5.67; 95% CI 1.51-21.31; P = 0.01). Four patients needed reintervention during a follow-up of 28.4 months (interquartile range 15.3-47.3). CONCLUSIONS: Preoperative respiratory distress negatively affected the outcomes of patients who required slide tracheoplasty. Therefore, early detection of congenital tracheal stenosis and aggressive slide tracheoplasty are crucial and obligatory to enhance long-term survival in this lethal congenital airway disease.

Slide tracheoplasty for congenital tracheal stenosis with involvement of the carina and bronchi: a case report.

A female newborn presented with respiratory distress at birth and was diagnosed with congenital tracheal stenosis. The stenosis was positioned at the distal trachea and compromised the carina and the right and left bronchi. She underwent surgical treatment using circulatory life support with veno-arterial peripheral extracorporeal membrane oxygenation, and the airway was reconstructed using the slide tracheoplasty technique to build a neocarina. The patient had an excellent postoperative course, was successfully weaned from extracorporeal membrane oxygenation and invasive ventilation, and was discharged.

Gene expression profiles in COVID-19-associated tracheal stenosis indicate persistent anti-viral response and dysregulated retinol metabolism.

INTRODUCTION: Coronavirus disease 2019 (COVID-19)-associated tracheal stenosis (COATS) may occur as a result of prolonged intubation during COVID-19 infection. We aimed to investigate patterns of gene expression in the tracheal granulation tissue of patients with COATS, leverage gene expression data to identify dysregulated cellular pathways and processes, and discuss potential therapeutic options based on the identified gene expression profiles. METHODS: Adult patients (age ≥ 18 years) presenting to clinics for management of severe, recalcitrant COATS were included in this study. RNA sequencing and differential gene expression analysis was performed with transcriptomic data for normal tracheal tissue being used as a control. The top ten most highly upregulated and downregulated genes were identified. For each of these pathologically dysregulated genes, we identified key cellular pathways and processes they are involved in using Gene Ontology (GO) and KEGG (Kyoto Encyclopedia of Genes and Genomes) applied via Database for Annotation, Visualization, and Integrated Discovery (DAVID). RESULTS: Two women, aged 36 years and 37 years, were included. The profile of dysregulated genes indicated a cellular response consistent with viral infection (CXCL11, PI15, CCL8, DEFB103A, IFI6, ACOD1, and DEFB4A) and hyperproliferation/hypergranulation (MMP3, CASP14 and HAS1), while downregulated pathways included retinol metabolism (ALDH1A2, RBP1, RBP4, CRABP1 and CRABP2). CONCLUSION: Gene expression changes consistent with persistent viral infection and dysregulated retinol metabolism may promote tracheal hypergranulation and hyperproliferation leading to COATS. Given the presence of existing literature highlighting retinoic acid's ability to favorably regulate these genes, improve cell-cell adhesion, and decrease overall disease severity in COVID-19, future studies must evaluate its utility for adjunctive management of COATS in animal models and clinical settings.

Biodegradable tracheal stents: our ten-year experience with adult patients.

BACKGROUND: Biodegradable (BD) stents made from polydioxanone have been used only in human airways. These stents combine the advantages of classical tracheal stents, and fewer side effects are expected due to their biocompatibility and their time-limited presence in airways. However, new clinical consequences have arisen. Here, the authors share their experiences with BD stents for tracheal indications, focusing on their safety and efficacy. METHODS: This was a retrospective review of a collected database of adult patients who underwent implantation of biodegradable tracheal stents between September 2013 and December 2022 at the Department of Respiratory Medicine of the 1st Faculty of Medicine in Prague and Thomayer University Hospital. The indications included functionally significant nonmalignant tracheal stenosis and tracheomalacia. Self-expandable, biodegradable, polydioxanone tracheal stents manufactured by ELLA-CS Ltd. (Hradec Kralove, Czech Republic) were implanted during rigid bronchoscopy under general anaesthesia. All patients were followed up in the department and were provided with the necessary care. The main efficacy and safety parameters and relationships were analysed using descriptive statistics and Fisher´s exact, Wilcoxon and Kruskal‒Wallis tests. RESULTS: A total of 65 stents were implanted in 47 adult patients. During the first two months after implantation, when adequate function was expected, the stent was found to be effective in 26 out of 39 patients who completed this period (66.7%). The clinical effectiveness reached 89.7%, as early restenoses were mostly mild and necessitated treatment in only 4 patients. The frequencies of significant mucostasis, migration and granulation tissue growth were 2.6%, 7.5% and 23.1%, respectively, during this period. Thirty-four participants completed the half-year follow-up period after the first or second stent insertion, and some were followed up beyond this period. Poor control of symptoms, the development of restenosis and the need for interventions were characteristic of this period as the stents degraded. Twenty-two patients who experienced remodelling or stabilization of the tracheal lumen achieved a stent-free state. Seven patients underwent subsequent surgical treatment. CONCLUSIONS: BD stents are safe and provide adequate tracheal support until they begin to degrade. The use of BD stents necessitates close monitoring of patients and accurate treatment of possible restenosis. TRIAL REGISTRATION: Based on project NT14146 - Biodegradable stents in the management of the large airways (2013-2015, MZ0/NT), registered on May 1, 2013, in the Research and Development and Innovation Information System of the Czech Republic and at ClinicalTrials.gov (reg. no. NCT02620319, December 2, 2015).

Tracheal metallic hybrid stent removal via tracheostomy: an unconventional approach.

Increasing use of tracheal expandable metallic hybrid stents will lead to common encounters with these devices in emergency airway management. The presence of these stents qualifies any patient as a challenge when an emergency tracheostomy is needed. We report an unorthodox technique of tracheostomy with concomitant removal of tracheal stent, without any major complications. Although the combined approach with bronchoscopy and tracheostomy has been reported in similar cases, we present a safe procedure when rigid bronchoscopy is not available.

Treatment of mixed and refractory post-tuberculosis tracheobronchial stenosis with L-shaped silicone stents: case series and a literature review.

The two patients included in the study had mixed and refractory post-tuberculosis tracheobronchial stenosis (PTTS), having experienced unsuccessful interventional therapies such as balloon dilation and V-shaped stent placement before the operation. Following the secure placement of L-shaped silicone stents, examinations with a fiberbronchoscope during the first and third months post-operation revealed a significant reduction in bronchial mucosa inflammation for both patients. Additionally, the opening diameter of the upper and lower branch segments increased, and chest CT scans indicated a noticeable absorption of left pulmonary lesions. Three months post-operation, fiberbronchoscopy confirmed the stable fixation of the stent without any movement. The patients exhibited substantial improvements in pulmonary function, dyspnea index, and blood gas analysis, with no reported adverse complications. After 7 months, a follow-up fiberbronchoscope for one case revealed excellent stent fixation. Simultaneously, the chest CT scan indicated favorable re-expansion. The placement of L-shaped silicone stents proves effective in preventing displacement, alleviating airway stenosis or obstruction, and ensuring the safety and efficacy of PTTS treatment - particularly in cases where V-shaped silicone stent placement has failed. To our knowledge, this is the first study describing the L-shaped silicone stent in two patients with PTTS.

Successful treatment of severe airway narrowing due to tuberculosis using special L-shaped silicone stentsThis article tells the story of two patients who suffered from a complex lung condition called post-tuberculosis tracheobronchial stenosis (PTTS). Imagine your airways - the tubes that carry air to your lungs - getting severely scarred and narrowed due to a past bout with tuberculosis. These two patients had tried previous treatments like balloon dilation (where a small balloon is inflated inside the narrowed airway to widen it) and using V-shaped stents (flexible supports placed in the airway to keep it open), but these methods didn't provide lasting relief. In this innovative approach, doctors used L-shaped silicone stents specifically designed to fit in the affected parts of the patients' airways. After placing these stents, regular checks showed remarkable improvements. The swelling in the airway lining reduced significantly, and the openings leading to the upper and lower parts of the lungs got wider. Chest X-rays (CT scans) even showed that the patient's left lung was healing well. Three months later, the stents stayed firmly in place, and neither patient experienced any problems. Breathing became easier, lung function tests improved, and blood tests showed better oxygen levels. Seven months down the line, one patient continued to do extremely well, with the stent securely fixed and the chest scan showing good lung expansion. This groundbreaking study shows that using L-shaped silicone stents can effectively treat PTTS when other methods fail. Not only do they stay in place, preventing blockages, but they also safely and effectively alleviate narrowing of the airways. It's the first time such L-shaped stents have been used successfully in PTTS patients, offering new hope for those facing similar challenges.

Involvement of PD-1+CD4+ T cells in the development of traumatic tracheal stenosis by regulating the IL-17/STAT3 pathway.

Studies have highlighted an upregulation of PD-1 expression in CD4+ T cells, which accelerates lung fibrosis by activating the IL-17/STAT3 pathway, leading to IL-17A and TGF-ß1 secretion. However, the relation with traumatic tracheal stenosis (TS) remains unexplored. Our analysis found significant increases in PD-1+CD4+ T cells, IL-17A, and TGF-ß1 in the TS patients (n = 10). The cellular model used CD4+ T cells co-cultured with bronchial fibroblasts while the animal model used a nylon brush to scrape the damaged tracheal mucosa. Interventions with PD-1 and STAT3 inhibitors both in vitro (n = 5) and in vivo (n = 6) showed decreased expression of TGF-ß1 and IL-17A in CD4+ T cells, decreased collagen I synthesis in vitro, and reduced tractal fibrosis in vivo. Furthermore, PD-1's modulation of the STAT3 was evident. This research unveils PD-1+CD4+ T cells' role in TS, thus suggesting a novel immunotherapeutic strategy to counteract tracheal fibrosis.

Application of OFA-based ERAS for video-assisted thoracoscopic surgery in elderly patients with airway stenosis: A case report.

BACKGROUND: Thoracic surgery without general anesthesia can be traced back to the First World War, and thoracic epidural block was used to complete the operation due to a large number of patients with gunshot wounds who needed emergency thoracic surgery. By reducing the intraoperative opioid dose, intraoperative and postoperative opioid-related adverse events such as respiratory depression, nausea and vomiting, delirium, hyperalgesia, and other side effects can be reduced to the benefit of patients. METHODS: A 72-year-old male patient was admitted to the hospital with a 5-day history of multifocal pain throughout the body caused by a fall. The injury was not treated at that time, and the pain gradually increased, accompanied by cough with difficulty expelling sputum. DIAGNOSES: Left lung contusion; traumatic pneumonia; multiple left rib fractures; left fluid pneumothorax; thyroid tumor of unknown nature, possibly malignant. Grade I tracheal stenosis; Sequelae of cerebral infarction. Because of goiter and severe tracheal compression, the patient was not intubated and received deopiated general anesthesia combined with epidural anesthesia to preserve spontaneous breathing. OUTCOMES: At the end of the video-assisted thoracoscopic exploration, the patient was immediately conscious and returned directly to the ward 6 min later. The patient was able to move freely after surgery and eat normally within 6 h of surgery. The postoperative visual analog scale score was 2 points, and there were no anesthetic complications during the follow-up. CONCLUSION: The opioid-free anesthesia strategy of tubeless general anesthesia, allowing spontaneous breathing combined with epidural anesthesia in elderly patients with tracheal stenosis undergoing video-assisted thoracoscopic surgery can not only avoid accidents and injuries caused by tracheal intubation and mechanical ventilation, but can also significantly reduce postoperative respiratory complications, optimize postoperative analgesia, and help achieve enhanced recovery after surgery.

Airway collapse hinders recovery in bronchoscopy therapy for postintubation tracheal stenosis patients.

BACKGROUND: Expiratory central airway collapse (ECAC) following postintubation airway stenosis (PITS) is a rare phenomenon. The impact of airway malacia and collapse on the prognosis and the success rate of bronchoscopic interventional therapy in patients with PITS had been inadequately investigated. OBJECTIVE: The aim of this research was to assess the influence of airway malacia and collapse on the efficacy of bronchoscopic interventional therapy in patients with PITS. DESIGN: This retrospective analysis examined the medical documentation of individuals diagnosed with PITS who underwent bronchoscopic intervention at the tertiary interventional pulmonology center of Emergency General Hospital from 2014 to 2021. MAIN OUTCOME MEASURES: Data pertaining to preoperative, perioperative, and postoperative stages were documented and subjected to analysis. RESULTS: The patients in malacia and collapse group (MC group) exhibited a higher frequency of perioperative complications, including intraoperative hypoxemia, need for reoperation within 24 h, and postoperative intensive care unit admission rate (P < 0.05, respectively). Meanwhile, patients in group MC demonstrated significantly worse postoperative scores (higher mMRC score and lower KPS score) compared to those in pure stenosis group (P < 0.05, respectively), along with higher degrees of stenosis after treatment and a lower success rate of bronchoscopic intervention therapy cured (P < 0.05, respectively). Pearson analysis results showed that these terms were all significantly correlated with the occurrence of airway malacia and collapse in the airway (P < 0.05, respectively). CONCLUSION: The presence of malacia or collapse in patients with PITS was associated with increased perioperative complications following bronchoscopic interventional therapy, and significantly reduced the long-term cure rate compared to patients with pure tracheal stenosis. Trial registration Chinese Clinical Trial Registry on 06/12/2021. REGISTRATION NUMBER: ChiCTR2100053991.

Factors affecting graft healing in laryngotracheal reconstruction: a retrospective single-center experience.

PURPOSE: To examine the factors that affect graft healing after laryngotracheal reconstruction (LTR). METHODS: We conducted a retrospective chart review at King Abdulaziz University Hospital, Riyadh, Saudi Arabia, between January-2008 and October-2023. We included all patients who underwent LTR and required anterior and/or posterior graft placement, while those who underwent procedures without graft placement and those with incomplete information were excluded. RESULTS: Forty-nine patients were analyzed. Most patients were pediatric (65.3%), male (65.3%), had no coexisting comorbidities (55.1%), and harbored grade 3-4 stenosis (59.2%). Thirty patients (61.2%) underwent open surgery. Various graft complications occurred including infection (n = 1, 2%), dehiscence (n = 3, 6.1%), scar (n = 6, 12.2%), and granulation (n = 29, 59.2%). Only 15 patients (30.65%) achieved the composite status of "healthy" graft. Among 43 patients who had postoperative cultures, positive results for Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus were observed in 10 and four patients, respectively. Open surgery and double-stage procedure were significantly associated with higher rates of granulation tissue formation. Pediatric-age group had significantly higher rate of complete epithelization compared to adult-age group. A significantly greater proportion of patients who had unhealthy grafts had open surgery. The rate of double-stage LTR was significantly higher in unhealthy grafts compared to healthy grafts. Prolonged stent duration was linked to various graft-related complications. Multivariate logistic regression analyses showed no statistically significant correlations between various factors and postoperative graft-related complications. CONCLUSION: Open surgery, double-stage procedure, pediatric age group, and stent duration were not significant risk factors associated with postoperative graft-related complications during LTR in multivariate analysis.

In-depth analysis of pre- and postoperative functional outcome parameters in patients receiving laryngotracheal surgery.

OBJECTIVES: Surgical treatment for airway stenosis necessitates personalized techniques based on the stenosis location and length, leading to favourable surgical outcomes. However, there is limited literature on functional outcomes following laryngotracheal surgery with an adequate number of patients. METHODS: We conducted a retrospective analysis of patients who underwent laryngotracheal surgery at the Department of Thoracic Surgery, Medical University of Vienna, from January 2017 to June 2021. The study included standardized functional assessments before and after surgery, encompassing spirometry, voice measurements, swallowing evaluation and subjective patient perception. RESULTS: The study comprised 45 patients with an average age of 51.9 ± 15.9 years, of whom 89% were female, with idiopathic being the most common aetiology (67%). Procedures included standard cricotracheal resection in 11%, cricotracheal resection with dorsal mucosal flap in 49%, cricotracheal resection with dorsal mucosal flap and lateral cricoplasty in 24% and single-stage laryngotracheal reconstruction in 16%. There were no in-hospital mortalities or restenosis cases during the mean follow-up period of 20.8 ± 13.2 months. Swallowing function remained intact in all patients. Voice evaluations showed a decrease in fundamental vocal pitch [203 (81-290) Hz vs 150 (73-364) Hz, P < 0.001] and dynamic voice range (23.5 ± 5.8 semitones vs 17.8 ± 6.7 semitones, P < 0.001). However, no differences in voice volume were observed (60.0 ± 4.1 dB vs 60.2 ± 4.8 dB, P = 0.788). The overall predicted voice profile changed from R0B0H0 to R1B0H1. CONCLUSIONS: Laryngotracheal surgery proves effective in fully restoring breathing capacity while preserving vocal function. Even in cases of high-grade and complex airway stenosis necessitating laryngotracheal reconstruction, favourable functional outcomes can be achieved.

Choice of suture technique may mitigate figure-of-8 deformity in slide tracheoplasty.

OBJECTIVES: To demonstrate varying degrees of immediate postoperative figure of 8 deformity following three different methods of tracheal suturing. STUDY DESIGN: Comparative ex-vivo study. METHODS: A fresh, unfixed rabbit trachea was harvested and bisected at its midpoint. The posterior membranous trachea was excised from both segments to mimic the anatomy of complete tracheal rings following longitudinal release. A slide tracheoplasty was performed on the same tracheal segments as an internal control, using three different methods of closure: simple running, running horizontal mattress, and a modified baseball stitch. Endoscopic and external photographs were taken immediately following repair to document the effect of closure technique on external and endoluminal anatomy. RESULTS: A simple running closure, in which traveling occurs between needle passes, showed the greatest degree of postoperative figure of 8 deformity. A running horizontal mattress suture closure showed less deformity and a modified running closure, in which traveling occurs within needle passes, showed the least deformity. CONCLUSIONS: Our study suggests that a minor modification of standard running closure techniques may help limit the common figure-of-8 deformity often noted following slide tracheoplasty. LAY SUMMARY: Figure of-8 deformity is a problem that can occur when repairing a narrow trachea referred to as tracheal stenosis. This deformity may be prevented using particular suture techniques which may decrease the likelihood that the trachea becomes blocked again following repair.

Biodegradable polydioxanone stents: histologic and structural effects in an experimental model of tracheal stenosis.

OBJECTIVES: To evaluate the biologic impact of polydioxanone (PDO) stenting in an animal model of inflammatory tracheal stenosis (TS). Additionally, to compare these results with those obtained in the same model without a stent and after placing one PDO stent in a healthy trachea. METHODS: 40 adult NZ rabbits were distributed into 3 groups: Group A, 8 animals with a healthy trachea and a PDO stent; group B, 17 rabbits with a TS and no stent; and group C, 15 animals with TS and a PDO stent. Histopathological studies included Masson's trichrome staining for submucosal fibrosis and Safranin O to assess structural integrity of cartilage. Morphometric analyses were performed in the 3 groups. RESULTS: Stent placement was successful in every case. Histological studies did not show a significant increase in tracheal wall collagen area and cartilage structure was not modified in those rabbits with a PDO stent, even in a TS scenario. Stent implantation permitted recovery of normal tracheal lumen levels in the TS model. CONCLUSIONS: PDO stenting in the normal trachea and in a model of TS neither caused increase in the collagen matrix nor modification of the cartilaginous support. Additionally, radial force exhibited by PDO stents was effective in restoring normal tracheal lumen when placed in a stenotic lesion. These findings suggest that they may be safe and useful in the setting of an acquired TS.

[Advances in the role of infection in the development of benign tracheal stenosis].

Benign tracheal stenosis (BTS) is a refractory disease with a complex pathogenesis and limited therapeutic drug effects. The management of benign tracheal stenosis remains a major challenge for the interventional physiologist. In recent years, the role of infection in the occurrence and development of tracheal stenosis has attracted some attention, but there is still some controversy. A clear understanding of the relationship between infection and tracheal stenosis is essential to elucidate the pathogenic mechanism of BTS, and then to improve early prevention and management of BTS. This article reviewed the research progress on BTS associated with infection to explore new effective interventions that can reduce the BTS.

Long- term outcomes of congenital tracheal stenosis after slide tracheoplasty.

PURPOSE: Long-term outcomes of slide tracheoplasty in patients with congenital tracheal stenosis (CTS) have rarely been reported. This study aimed to clarify the long-term outcomes of CTS after slide tracheoplasty. METHODS: The medical records of 33 patients who underwent slide tracheoplasty for CTS at our institution between January 2005 and July 2018, with a follow-up duration > 5 years, were retrospectively reviewed. Patients' characteristics, perioperative condition, operative management, postoperative course, tracheal stenosis rates and growth data, were collected from medical records. RESULTS: The median operative age, minimum tracheal diameter, length of stenosis, duration of hospital stays, and follow-up duration were 8 months, 2.4 mm, 35 mm, 39 days, and 90 months, respectively. One patient died of bleeding in the right lung at 126 months postoperatively. Among the 10 patients requiring postoperative tracheostomy, seven were successfully decannulated at a median of 65 months postoperatively. Tracheal stenosis rates improved postoperatively and were subsequently maintained. Growth impairment and psychomotor delay were observed in 9 and 16 patients, respectively with significant differences found only in cases with genetic abnormalities and not in tracheal stenosis severity. CONCLUSION: Slide tracheoplasty for CTS leads to favorable long-term outcomes. However, various associated anomalies may influence growth and psychomotor development, emphasizing the importance of adequate support.

Study on the rationality of small diameter metallic airway stent in treatment of tracheal stenosis in injured rabbits.

BACKGROUND: To observe the occurrence of related complications after self-expandable metallic (SEM) airway stents implantation with different diameters at different time points, and to provide theoretical basis for the optimal chioce of existing airway stents in clinical practice. METHODS: Healthy New Zealand white rabbits were used to establish benign tracheal stenosis models after chest CT examination. Forty-fivemodel rabbits with more than 50% of airway stenosis were divided into two groups. Small-diameter SEM stents (The ratio of stent diameter to airway diameter is nearly 1.0) were implanted in Group A in 21 rabbits, and large-diameter tracheal stents (The ratio of stent diameter to airway diameter is more than 1.2) were implanted in Group B in 24 rabbits. Stent-related complications were observed after stent implantation in 2nd,4th,8th, and 12th week by bronchoscopygross anatomy, pathological and the expressions of IL-1RA, IL-8 and MMP9 in involved tracheal. RESULTS: The incidence rate of tracheomalacia of stent was significantly higher in group B (24/24 100%) than that in group A (1 /21,4.8%) (P < 0.05). The incidence rate of scar contracture at both ends of stent was significantly higher than in group B (11 / 24,45.8%) that in group A (2 /21, 9.5%) (P < 0.05). The pathological results of both A and B showed that the columnar epithelium of bronchial mucosa began to damage and detach, inflammatory cells infiltrated after 2nd and 4th week of stenting, The epithelium was repaired, the lamina propria glands almost disappeared, collagen fiber proliferation was obvious, and scars were formed after 8th and 12th week of stenting. ELISA results revealed that the expressions of IL-1RA, IL-8, and MMP9 were increased in the stent group than in model rabbit with benign tracheal stenosis. IL-1RA and MMP9 increased at different periods in group B, but the expression of IL-1RA and MMP9 showed a tread of increasing in the early stage and then decreasing in group A. CONCLUSION: Metal stents can cause different degrees of stent-related complications in rabbits with benign tracheal stenosis. The incidence of stent-induced tracheomalacia and scar contracture were higher in Group B than that in Group A. IL-1RA, IL-8 and MMP9 may be involved in the development of complications after stentimplantation and peak value of group B movered backward. ing.