Outcomes of surgical treatment of tracheobronchomalacia in children.

BACKGROUND: Tracheobronchomalacia (TBM) is characterized by excessive dynamic airway collapse. Severe TBM can be associated with substantial morbidity. Children with secondary TBM associated with esophageal atresia/tracheoesophageal fistula (EA/TEF) and vascular-related airway compression (VRAC) demonstrate clinical improvement following airway pexy surgery. It is unclear if children with severe primary TBM, without secondary etiologies (EA/TEF, vascular ring, intrinsic pulmonary pathology, or complex cardiac disease) demonstrate clinical improvement following airway pexy surgery. MATERIALS AND METHODS: The study cohort consisted of 73 children with severe primary TBM who underwent airway pexy surgery between 2013 and 2020 at Boston Children's Hospital. Pre- and postoperative symptoms as well as bronchoscopic findings were compared with Fisher exact test for categorical data and Student's t-test for continuous data. RESULTS: Statistically significant improvements in clinical symptoms were observed, including cough, noisy breathing, prolonged respiratory infections, pneumonias, exercise intolerance, cyanotic spells, brief resolved unexplained events (BRUE), and noninvasive positive pressure ventilation (NIPPV) dependence. No significant differences were seen regarding oxygen dependence, ventilator dependence, or respiratory distress requiring NIPPV. Comparison of pre- and postoperative dynamic bronchoscopy findings revealed statistically significant improvement in the percent of airway collapse in all anatomic locations except at the level of the upper trachea (usually not malacic). Despite some initial improvements, 21 (29%) patients remained symptomatic and underwent additional airway pexies with improvement in symptoms. CONCLUSION: Airway pexy surgery resulted in significant improvement in clinical symptoms and bronchoscopic findings for children with severe primary TBM; however, future prospective and long-term studies are needed to confirm this benefit.

Surgical treatment for severe pediatric tracheobronchomalacia: the 20-year experience of a single center.

OBJECTIVE: In children with tracheobronchomalacia, surgical management should be reserved for the most severe cases and be specific to the type and location of tracheobronchomalacia. The goal of this study is to describe the presentation and outcomes of children with severe tracheobronchomalacia undergoing surgery. METHODS: Retrospective case series of 20 children operated for severe tracheobronchomalacia at a tertiary hospital from 2003 to 2023. Data were collected on symptoms age at diagnosis, associated comorbidities, previous surgery, age at surgery, operative approach, time of follow-up, and outcome. Surgical success was defined as symptom improvement. RESULTS: The most frequent symptoms of severe tracheobronchomalacia were stridor (50 %), cyanosis (50 %), and recurrent respiratory infections (45 %). All patients had one or more underlying conditions, most commonly esophageal atresia (40 %) and prematurity (35 %). Bronchoscopy were performed in all patients. Based on etiology, patients underwent the following procedures: anterior aortopexy (n = 15/75 %), posterior tracheopexy (n = 4/20 %), and/or posterior descending aortopexy (n = 4/20 %). Three patients underwent anterior aortopexy and posterior tracheopexy procedures. After a median follow-up of 12 months, 16 patients (80 %) had improvement in respiratory symptoms. Decannulation was achieved in three (37.5 %) out of eight patients with previous tracheotomy. The presence of dying spells at diagnosis was associated with surgical failure. CONCLUSIONS: Isolated or combined surgical procedures improved respiratory symptoms in 80 % of children with severe tracheobronchomalacia. The choice of procedure should be individualized and guided by etiology: anterior aortopexy for anterior compression, posterior tracheopexy for membranous intrusion, and posterior descending aortopexy for left bronchus obstruction.

Primary Posterior Tracheopexy at Time of Esophageal Atresia Repair Significantly Reduces Respiratory Morbidity.

PURPOSE: Esophageal atresia with tracheoesophageal fistula (EA/TEF) is often associated with tracheobronchomalacia (TBM), which contributes to respiratory morbidity. Posterior tracheopexy (PT) is an established technique to treat TBM that develops after EA/TEF repair. This study evaluates the impact of primary PT at the time of initial EA/TEF repair. METHODS: Review of all newborn primary EA/TEF repairs (2016-2021) at two institutions. Long-gap EA and reoperative cases were excluded. Based on surgeon preference and preoperative bronchoscopy, neonates underwent primary PT (EA + PT Group) or not (EA Group). Perioperative, respiratory and nutritional outcomes within the first year of life were evaluated. RESULTS: Among 63 neonates, 21 (33%) underwent PT during EA/TEF repair. Groups were similar in terms of demographics, approach, and complications. Neonates in the EA + PT Group were significantly less likely to have respiratory infections requiring hospitalization within the first year of life (0% vs 26%, p = 0.01) or blue spells (0% vs 19%, p = 0.04). Also, they demonstrated improved weight-for-age z scores at 12 months of age (0.24 vs -1.02, p < 0.001). Of the infants who did not undergo primary PT, 10 (24%) developed severe TBM symptoms and underwent tracheopexy during the first year of life, whereas no infant in the EA + PT Group needed additional airway surgery (p = 0.01). CONCLUSION: Incorporation of posterior tracheopexy during newborn EA/TEF repair is associated with significantly reduced respiratory morbidity within the first year of life. LEVEL OF EVIDENCE: Level III.

Tracheobronchomalacia: an unusual cause of debilitating dyspnoea and its surgical management.

Tracheobronchomalacia (TBM) is a progressive weakening of the airways, leading to collapse and dyspnoea. TBM can be misdiagnosed when multiple chronic conditions accompany it. Tracheobronchoplasty (TBP) is indicated for severe symptomatic TBM, diagnosed by bronchoscopy and CT thorax. We report the case of a patient who underwent tracheal resection and reconstruction for continuing dyspnoea post argon therapy, TBP and a failure to tolerate extracorporeal membrane oxygenation-assisted Y-stent insertion. Relevant background history includes asthma, sleep apnoea, reflux, cardiomyopathy and a high body mass index. Bronchoscopy postreconstruction showed patent airways. Airway reconstruction was a viable management option for this patient's TBM. TBP is a treatment option for TBM. In this case, tracheal resection was required to sustain benefit. In addition, surveillance bronchoscopies will be carried out every year.

Single-center review on safety of biodegradable airway stenting in pediatric population.

BACKGROUND: Tracheobronchomalacia (TBM) and airway stenosis are recognized etiologies of airway obstruction among children. Their management is often challenging, requiring multiple interventions and prolonged respiratory support with associated long-term morbidity. Metallic or silicone stents have been used with mixed success and high complication rates. More recently biodegradable Ella stents (BES) provided an attractive interventional option. OBJECTIVES: We report our experience in the treatment of TBM and vascular airway compression using BES. We deliberately downsized them to minimize intraluminal granulation tissue formation. MATERIALS AND METHODS: Retrospective study over an 8-year period between November 2012 and December 2020 of pediatric patients with severe airway obstruction requiring airway stenting for extubation failure, malacic death spells, recurrent chest infections, or lung collapse. RESULTS: Thirty-three patients (5 tracheal and 28 bronchial diseases) required 55 BES during the study period. The smallest patient weighed 1.8 kg. Median age of patient at first stent implantation was 13.1 months (IQR 4.9-58.3). The majority of the bronchial stents were in the left main bronchus (93%), of which 57% for vascular compression. Repeat stents were used in 19 patients (57.7%), with a range of two to four times. We did not experience erosion, infection, or obstructive granuloma needing removal by forceps or lasering. Three stent grid occluded with secretions needing bronchoscopic lavage. Stent migration occurred in three patients. CONCLUSIONS: BES holds promise as a treatment option with low rate of adverse effects for a specific subset of pediatric patients with airway malacia or vascular compression. Further studies are warranted.

Dynamic computed tomography for evaluation of tracheobronchomalacia in premature infants with bronchopulmonary dysplasia.

INTRODUCTION: Dynamic computed tomography (dCT) gives real-time physiological information and objective descriptions of airway narrowing in tracheobronchomalacia (TBM). There is a paucity of literature in the evaluation of TBM by dCT in premature infants with bronchopulmonary dysplasia (BPD). The aim of this study is to describe the findings of dCT and resultant changes in management in premature infants with TBM. METHODS: A retrospective study of 70 infants was performed. Infants included were <32 weeks gestation without major anomalies. TBM was defined as ≥50% expiratory reduction in cross-sectional area with severity defined as mild (50%-75%), moderate (≥75%-90%), or severe (≥90%). RESULTS: Dynamic CT diagnosed malacia in 53% of infants. Tracheomalacia was identified in 49% of infants with severity as 76% mild, 18% moderate, and 6% severe. Bronchomalacia was identified in 43% of infants with varying severity (53% mild, 40% moderate, 7% severe). Resultant management changes included PEEP titration (44%), initiation of bethanechol (23%), planned tracheostomy (20%), extubation trial (13%), and inhaled ipratropium bromide (7%). CONCLUSION: Dynamic CT is a useful noninvasive diagnostic tool for airway evaluation of premature infants. Presence and severity of TBM can provide actionable information to guide more precise clinical decision making.

How risky is it to remove an airway stent?

BACKGROUND: Airway stent removal has traditionally been associated with a high complication rate. Most studies on stent removal are over a decade old, prior to newer anti-cancer therapies, and by including non-contemporary and uncovered metal stents, may not reflect the current practices. We review our experience at Mount Sinai Hospital to report outcomes of stent removal with more contemporary practices. METHODS: A retrospective review was carried out of all the airway stent removals performed between 2018 to 2022, in adult patients with benign or malignant airway diseases. Stents inserted and removal for stent trials for tracheobronchomalacia were excluded from the final analysis. RESULTS: Forty-three airway stents removals in 25 patients were included. Twenty-five (58%) stents were removed in 10 patients with benign diseases, and 18 (42%) stents were removed in the remaining 15 patients with malignant diseases. Patients with benign disease were more likely to have their stent removed (OR 3.88). 63% of the stents removed were silicone. The most common reasons for stent removal were migration (n = 14, 31.1%) and treatment response (n = 13, 28.9%). Rigid bronchoscopy was used in 86% of cases. Ninety-eight percent of removals were accomplished in a single procedure. The median time to removal of stents was 32.5 days. Three complications were noted: hemorrhage (n = 1, 2.3%) and stridor (n = 2, 4.6%); one not directly related to the stent removal. CONCLUSIONS: Covered metal or silicone airway stents, in the era of contemporary stents, better cancer-directed therapies and surveillance bronchoscopies, can be removed safely with the use of rigid bronchoscopy.

Tracheobronchoplasty: Indications and Best Approaches.

Tracheobronchomalacia (TBM) is an increasingly recognized abnormality of the central airways in patients with respiratory symptoms. Severe TBM in symptomatic patients warrants screening dynamic CT of the chest and/or awake dynamic bronchoscopy. The goal of surgical repair is to restore the C-shaped configuration of the airway lumen and splint or secure the lax posterior membrane to the mesh to ameliorate symptoms. Robotic tracheobronchoplasty is safe and associated with improvements in pulmonary function and subjective improvement in quality of life.

Characteristics analysis of 157 cases of central airway stenosis due to tracheobronchial tuberculosis: A descriptive study.

Background: Tracheobronchial stenosis, particularly central airway stenosis, which frequently results in severe complications such as lung damage, occurs in patients with tracheobronchial tuberculosis (TBTB). Objectives: To analyze the clinical characteristics of patients with central airway stenosis due to tuberculosis (CASTB). Methods: Retrospective analysis was performed on the clinical features, radiological features, bronchoscopic features and treatment of 157 patients who were diagnosed with CASTB in two tertiary hospitals in Chongqing, China, from May 2020 to May 2022. Results: CASTB mostly occurs in young patients and females. Patients with CASTB exhibited different symptoms repeatedly during the disease, especially varying degrees of dyspnea, prompting many patients to undergo bronchoscopic intervention and even surgery. Patients with cicatricial strictures constituted the highest proportion of the TBTB subtype with CASTB and 35.7% of the patients with CASTB were found to have tracheobronchomalacia (TBM) under bronchoscopy. CASTB and TBM mainly involved the left main bronchus. Patients with lower levels of education had higher rates of TBM. Patients with TBM manifested shortness of breath more frequently than patients without TBM. Patients with TBTB who had undergone bronchoscopic interventions have a higher rate of TBM. Conclusions: Despite mostly adequate anti-tuberculosis chemotherapy, patients with TBTB can present with CASTB involving severe scarring stenosis, bronchial occlusion, tracheobronchomalacia and even destroyed lung.

Posterior tracheopexy for preterm infants with severe bronchopulmonary dysplasia and severe tracheobronchomalacia: A case series.

We report a series of four patients with severe bronchopulmonary dysplasia (BPD) who underwent posterior tracheopexy for severe tracheomalacia (TM). While posterior tracheopexy is an established surgical treatment for TM associated with tracheoesophageal fistula, it has not been previously described in TM associated with BPD. There were no significant intraoperative or postoperative complications from the surgeries. Three of the four patients required tracheostomy and mechanical ventilation, which may reflect the degree of lung disease and other multisystem comorbidities in these patients. More investigation is needed to determine whether posterior tracheopexy is an effective surgical option for TM related to BPD.

Reassessing the role of tracheobronchomalacia in persistent wheezing.

BACKGROUND: Tracheobronchomalacia (TBM) is often manifested as wheezing. Reassessing the role of TBM in persistent wheezing in children is essential. METHODS: We selected children who were diagnosed with TBM by bronchoscopy and who underwent bronchoscopic reexamination for persistent wheezing or chronic cough between January 2009 and July 2019. The clinical and bronchoscopy data were collected and retrospectively reviewed. For statistical analysis, we used the Kaplan-Meier method, Kruskal-Wallis test, and Fisher exact test. RESULTS: A total of 79 patients (57 males and 22 females) were included. The median age of the first TBM diagnosis was 7 (interquartile [IQR] 4-11) months. The median age of the first wheezing episode was 4 (IQR 3-7) months. During the time interval between the two bronchoscopies, malacia lesions resolved in 50 patients (63.3%), improvement was seen in 14 patients (17.7%), no change was observed in 11 patients (13.9%), and the condition was aggravated in 4 patients (5.1%). The malacia lesions in 37 patients resolved before 2 years of age. Among the 50 resolved patients, 22 patients (44.0%) reported wheezing three times or more between bronchoscopy evaluations, and 13 of these 22 patients (59.1%) with atopy or family history of allergic diseases were ultimately diagnosed with bronchial asthma. CONCLUSIONS: In children with persistent wheezing, the role of TBM should be reassessed, especially in those with atopy or family history of allergic diseases, and bronchial asthma should be considered early.

Cautionary tales in the use of magnets for the treatment of long gap esophageal atresia.

BACKGROUND: The use of magnets for the treatment of long gap esophageal atresia or "magnamosis" is associated with increased incidence of anastomotic strictures; however, little has been reported on other complications that may provide insight into refining selection criteria for appropriate use. METHODS: A single institution, retrospective review identified three cases referred for treatment after attempted magnamosis with significant complications. Their presentation, imaging, management, and outcomes were reviewed. RESULTS: All three patients had prior cervical or thoracic surgery to close a tracheoesophageal fistula prior to magnamosis, creating scar tissue that can prevent magnet induced esophageal movement, leading to either magnets not attracting enough or erosion into surrounding structures. Two patients had a reported four centimeter esophageal gap prior to attempted magnamosis, both failing to achieve esophageal anastomosis, suggesting that these gaps were either measured on tension with variability in gap measurement technique, or that the esophageal segments were fixed in position from scar tissue and unable to elongate. One patient had severe tracheobronchomalacia requiring tracheostomy, with improvement in his airway after eventual tracheobronchopexies, highlighting that magnamosis does not address comorbidities often associated with this patient population. CONCLUSIONS: We propose the following inclusion criteria and considerations for magnamosis: an esophageal gap truly less than four centimeters off tension with standardized measurement across centers, cautious use with a history of prior thoracic or cervical esophageal surgery, no associated tracheobronchomalacia or great vessel anomaly that would benefit from concurrent repair, and ideally to be used in centers equipped to manage potential complications. LEVEL OF EVIDENCE: Level IV treatment study.

Traqueobroncoplastia por malacia / Tracheobronchoplasty for malacia

RESUMEN La traqueobroncomalacia es una enfermedad de la vía aérea central caracterizada por una debilidad de la pared, con disminución dinámica de la luz de la tráquea y grandes bronquios principalmente durante la espiración. Genera síntomas crónicos que pueden evolucionar hasta la falla respiratoria grave, frecuentemente diagnosticados de forma errónea como asma o enfermedad pulmonar obstructiva crónica (EPOC). Presentamos el caso de una paciente femenina de 70 años, con antecedente de artritis reumatoide y múltiples internaciones por cuadros respiratorios infecciosos en los 3 años previos.

ABSTRACT Tracheobroncomalacia is a disease of the central airway due to weakness of the wall with dynamic narrowing of the lumen of the trachea and mainstem bronchi during exhalation. It produces chronic symptoms that can progress to severe respiratory failure, often misdiagnosed as asthma or chronic obstructive pulmonary disease (COPD). We report the case of a 70-year-old female patient with a history of rheumatoid arthritis and multiple hospitalizations for recurrent respiratory infections over the past 3 years.

Silicon stent placement via rigid bronchoscopy for the treatment of central airway obstruction in infants: Case series.

INTRODUCTION: Rigid bronchoscopy has been proven to be an excellent tool for the diagnosis and management of several causes of central airway obstruction (CAO). The invasive treatment of silicone bronchobrachial stenting has been performed in children and adults with CAO, and satisfying results were obtained in previous studies. However, there are few reports on infants with central airway obstruction treated with stenting via rigid bronchoscopy. This technique remains a challenge to pediatric thoracic surgeons, pediatric interventional pulmonologists, and otolaryngologists who struggle to treat airway obstruction disease. PATIENT CONCERNS: Four patients were presented to our hospital with complaints of dyspnea for a period of time after their birth. DIAGNOSIS: Three patients were diagnosed as tracheobronchomalacia, and tracheoesophageal fistula. INTERVENTIONS: Four patients were treated with silicone stenting through rigid bronchoscopy. OUTCOMES: Silicon stent was adequate for improving the obstruction of the tracheal tract. All the patients were followed-up longer than 6 months. Three patients could breathe normally; the stent migrated in only 1 patient. CONCLUSION: Invasive silicone tracheobronchial stenting via rigid bronchoscopy is a viable option for infants with CAO. Choosing an appropriate size is a critical factor for success of stenting according to our experience.

Central Airway Collapse, an Underappreciated Cause of Respiratory Morbidity.

Dyspnea, cough, sputum production, and recurrent respiratory infections are frequently encountered clinical concerns leading patients to seek medical care. It is not unusual for a well-defined etiology to remain elusive or for the therapeutics of a presumed etiology to be incompletely effective. Either scenario should prompt consideration of central airway pathology as a contributor to clinical manifestations. Over the past decade, recognition of dynamic central airway collapse during respiration associated with multiple respiratory symptoms has become more commonly appreciated. Expiratory central airway collapse may represent the answer to this diagnostic void. Expiratory central airway collapse is an underdiagnosed disorder that can coexist with and mimic asthma, chronic obstructive pulmonary disease, and bronchiectasis. Awareness of expiratory central airway collapse and its spectrum of symptoms is paramount to its recognition. This review includes clear definitions, diagnostics, and therapeutics for this challenging condition. We performed a narrative review through the PubMed (MEDLINE) database using the following MeSH terms: airway collapse, tracheobronchomalacia, tracheomalacia, and bronchomalacia. We include reports from systematic reviews, narrative reviews, clinical trials, and observational studies from 2005 to 2020. Two reviewers evaluated potential references. No systematic reviews were found. A total of 28 references were included into our review. Included studies report experience in the diagnosis and/or treatment of dynamic central airway collapse; case reports and non-English or non-Spanish studies were excluded. We describe the current diagnostic dilemma, highlighting the role of dynamic bronchoscopy and tracheobronchial stent trial; outline the complex therapeutic options (eg, tracheobronchoplasty); and present future directions and challenges.

Aortic uncrossing and tracheobronchopexy corrects tracheal compression and tracheobronchomalacia associated with circumflex aortic arch.

OBJECTIVE: Aortic uncrossing is an effective procedure for relieving the external airway compression from a circumflex aortic arch by transferring the aortic arch to the same side as the descending aorta. However, patients frequently have residual tracheobronchomalacia (TBM), which may result in persistent postoperative symptoms. We review a series of patients who underwent an aortic uncrossing and concomitant tracheobronchopexy to correct the airway compression and residual TBM. METHODS: Retrospective review of all patients who underwent aortic uncrossing and concomitant tracheobronchopexy at a single institution between September 2016 and March 2019. Preoperative evaluation included computed tomography angiography and rigid 3-phase dynamic bronchoscopy. RESULTS: Eight patients who ranged in age from 4 months to 15 years with significant respiratory symptoms underwent an aortic uncrossing procedure with concomitant tracheobronchial procedures. Mild hypothermic cardiopulmonary bypass (mean time, 105.6 ± 39.4 min) and regional perfusion (mean time, 44 ± 10 min) were used without circulatory arrest. Intraoperative bronchoscopy demonstrated no patients had residual TBM. There were no postoperative mortalities, neurologic complications, chylothoraces, coarctations, or obstructed aortic arches. Two patients required tracheostomy and gastrostomy for bilateral recurrent laryngeal nerve paresis (patients 2 and 3). One patient with bronchial stenosis after concomitant slide bronchoplasty required stenting. At a median follow-up of 22 months (range, 5-34 months), all patients were alive without evidence of significant respiratory symptoms. CONCLUSIONS: The aortic uncrossing procedure can be performed safely in pediatric patients of all ages without circulatory arrest. Concomitant procedures addressing associated TBM can significantly improve respiratory symptoms.

[Evaluation with chest CT scan of CPAP as a treatment for tracheobronchomalacia in the frame of a Mounier-Kuhn syndrome]. / Évaluation par tomodensitométrie thoracique d'un traitement de la trachéobronchomalacie par pression positive continue dans le cadre d'un syndrome de Mounier­Kuhn.

INTRODUCTION: Tracheobronchomegaly disease is often associated with a tracheobronchomalacia which is responsible for recurrent lower respiratory tract infections. Currently there is no evidence to support any specific treatment for the condition. CASE REPORT: We report the case of a 79 years old patient presenting with tracheobronchomegaly in the context of Mounier-Kuhn syndrome complicated by a tracheobronchomalacia responsible for her symptomatology. The diagnosis of tracheobronchomalacia had been confirmed by high-resolution chest computed tomography (CT) with expiratory slices and virtual bronchoscopy. Treatment with continuous positive airway pressure (CPAP) was proposed, and we confirmed its efficacy using high-resolution chest CT, which showed a decrease in tracheobronchial collapse and a reduction in air trapping. CONCLUSIONS: Three-dimensional virtual bronchoscopy is an interesting tool and a noninvasive method to diagnose tracheobronchomegaly for patients who are at a high anesthetic risk. It is also possible to use it demonstrate the effect of CPAP in tracheobronchomalacia.

Tracheobronchomalacia, Tracheobronchial Compression, and Tracheobronchial Malformations: Diagnostic and Treatment Strategies.

Tracheobronchomalacia (TBM) is an excessive dynamic narrowing of the airway that is greatest with increased mediastinal pressure such as coughing, Valsalva, and forced expiration. Airway compression and/or cartilage malformation is a fixed or static narrowing of the airway typically caused by great vessel malposition and/or abnormalities and may also contribute to airway narrowing. Although imprecise and misleading, the term TBM is often used to represent both problems, static and dynamic airway narrowing, which only serves to confuse and may mislead the treatment team into ineffective therapies. The consequences of airway narrowing caused by dynamic TBM and/or static compression includes a range of clinical signs and symptoms, depending on the location, extent, and severity of the airway collapse. All patients with mild to severe TBM benefit from medical management to optimize airway clearance of mucus. The milder cases of TBM may become asymptomatic with this therapy, allowing time for the child to grow and the airway to enlarge without the consequences of recurrent infections. In cases of more severe TBM with clinical sequelae, more aggressive management may be warranted. Multiple options for surgical intervention are available. This article discusses the details of clinical presentation, evaluation, diagnosis, and a variety of treatments.

Thermoablative Techniques for Excessive Central Airway Collapse: An Ex Vivo Pilot Study on Sheep Tracheal Tissue.

BACKGROUND: Tracheobronchoplasty is the definitive treatment for patients with symptomatic excessive central airway collapse. This procedure is associated with high morbidity and mortality rates. Bronchoscopic techniques are an appealing alternative with less morbidity and the ability to apply it in nonsurgical patients. Although thermoablative methods have been proposed as treatment options to induce fibrosis of the posterior tracheobronchial wall, no studies have compared direct histologic effects of such methods. This study compared the effects of electrocautery, radiofrequency ablation, potassium titanyl phosphate laser, and argon plasma coagulation (APC) in the tracheobronchial tree in an ex vivo animal model. METHODS: Four adult sheep cadavers were used for this study. Under flexible bronchoscopy, the posterior tracheal membrane was treated using different power settings on 4 devices. The airways were assessed for the presence of treatment-related histopathologic changes. RESULTS: Histologic changes observed were that of acute thermal injury including: surface epithelium ablation, collagen fiber condensation, smooth muscle cytoplasm condensation, and chondrocyte pyknosis. No distinct histologic differences in the treated areas among different modalities and treatment effects were observed. APC at higher power settings was the only modality that produced consistent and homogenous thermal injury effects across all tissue layers with no evidence of complete erosion. CONCLUSION: Although electrocautery, radiofrequency ablation, potassium titanyl phosphate laser, and APC all induce thermal injury of the airway wall, only APC at high power settings achieves this effect without complete tissue erosion, favoring potential regeneration and fibrosis. Live animal studies are now plausible.