Síndrome de Williams-Campbell: reporte de caso / Williams-Campbell Syndrome: Case Report

El síndrome de Williams-Campbell (SWC) es una entidad clínica caracterizada por la deficiencia de cartílago en la pared bronquial de los bronquios subsegmentarios. Es una condición congénita que por lo general se diagnostica en la niñez, pero hay reportes de caso en la población adulta y se cree que esto se debe a un menor déficit de cartílago. Los síntomas principales de esta condición son la presencia de tos, disnea e infecciones respiratorias a repetición. Radiológicamente, se evidencia la presencia de bronquiectasias de pared delgada. El diagnóstico se basa en descartar otras causas más comunes de bronquiectasias, así como en la identificación de las características radiológicas y la presencia del componente congénito. Presentamos el caso de un joven con síntomas respiratorios desde la infancia, con necesidad de múltiples hospitalizaciones por procesos infecciosos de origen pulmonar a repetición, con lo cual se llega al diagnóstico de un síndrome de Williams-Campbell.

Williams-Campbell syndrome (WCS) is a clinical entity characterized by cartilage deficiency in the bronchial wall of the subsegmental bronchi. It is a congenital condition that is usually diagnosed in childhood, but there are case reports in the adult population, and it is believed that this is due to a minor cartilage deficiency. The main symptoms of this condition are the presence of cough, dyspnea and repeated respiratory infections. Radiologically, the presence of thin-walled bronchiectasis is evident. The diagnosis is based on ruling out other more common causes of bronchiectasis, as well as identifying the radiological characteristics and the presence of the congenital component. We present the case of a young man with respiratory symptoms since childhood requiring multiple hospitalizations due to repeated infectious processes of pulmonary origin, in which the diagnosis of Williams-Campbell syndrome was reached.

Prevalence and Clinical Characteristics of Pediatric Lower Airway Malacia: Case Series from a Tertiary Center in Turkey.

Introduction: Lower airway malacia (LAM) is characterized by a reduction in the cross-sectional luminal area during quiet respiration. There is no gold standard diagnostic test; however, flexible fiberoptic bronchoscopy (FFB) is most frequently utilized. The exact prevalence and incidence of LAM are unknown. This study aimed to determine the prevalence rates of pediatric patients diagnosed with LAM, offer a detailed understanding of their demographic and clinical characteristics, and investigate distinctions between two specific types of LAM, namely, tracheomalacia (TM) and bronchomalacia (BM). Materials and Methods: Patients younger than 18 years diagnosed with LAM using FFB were included in this retrospective case series. Demographic and clinical characteristics and comorbid disorders were compared between patients with isolated BM and those with isolated TM or tracheobronchomalacia (TM/TBM). Results: Among 390 patients who underwent FFB, 65 (16.6%) were diagnosed with LAM, 16 (24.6%) with TM, and 56 (86.2%) with BM. The median age at diagnosis was 15 months. Among them, 59 (90.8%) had other comorbidities; gastrointestinal (GI) disorders were the most common (38.5%). The most common indications for bronchoscopy were recurrent/prolonged lower respiratory tract infections (LRTI) or wheezing (43.1%), while the most frequently observed respiratory physical examination finding was stridor (35.4%). Patients with TM/TBM had significantly higher frequencies of premature births, stridor, retraction, and GI disorders. Conclusion: Patients with stridor without typical laryngomalacia features or recurrent or prolonged LRTI should undergo prompt evaluation for LAM. The potential coexistence of GI disorders such as gastroesophageal reflux disease and swallowing dysfunction should also be considered.

Expiratory Central Airway Collapse and Dynamic Hyperinflation During Peroral Endoscopic Myotomy: A Case Report.

In tracheobronchomalacia, the structural weakening of the airway results in altered ventilatory mechanics. This case report describes a patient with known tracheobronchomalacia who experienced expiratory central airway collapse and dynamic pulmonary hyperinflation during peroral endoscopic myotomy (POEM) to treat symptomatic achalasia. We discuss the physiological considerations and potential complications of a POEM procedure with superimposed tracheobronchomalacia and present perioperative strategies for the prevention and management of this potentially deleterious combination. Although tracheobronchomalacia was a known condition in our patient, it is likely an underdiagnosed condition that may first present intraoperatively.

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.

Acquired tracheobronchomalacia developed following voice prosthesis implantation.

Acquired tracheobronchomalacia (ATBM) is a condition in which the tracheobronchial wall and cartilage progressively lose their rigidity, resulting in dynamic collapse during exhalation. In this report, we present a case of ATBM that developed following voice prosthesis implantation. To the best of our knowledge, this is the first documented case of such a condition in the medical English literature based on a PubMed search. A 63-year-old man was referred to National Kyushu Cancer Center in Japan with complaints of pharyngeal pain and a laryngeal tumor. The tumor was diagnosed as laryngeal cancer, and the patient underwent laryngectomy. Three months after the surgery, we implanted a voice prosthesis through a tracheoesophageal puncture. Two months after implantation, the patient experienced dyspnea. This condition was subsequently diagnosed as ATBM through computed tomography and bronchofiberscope examinations. After the removal of the voice prosthesis, there has been no progression of ATBM for over five years. While ATBM may not be a common occurrence in the practice of head and neck surgeons, it should be considered as a potential complication when patients report dyspnea following voice prosthesis implantation.

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.

The effect of bethanechol on tracheobronchomalacia in preterm infants with bronchopulmonary dysplasia: a retrospective cohort study.

OBJECTIVE: Bethanechol has demonstrated improvement in trachealis tone in animal models, but no trials have studied efficacy in infants. This study aimed to examine if bethanechol improves a standardized pulmonary severity score (PSS) in infants with severe bronchopulmonary dysplasia with a diagnosis of tracheobronchomalacia (TBM). STUDY DESIGN: This retrospective cohort study evaluated cases treated with bethanechol matched with controls who did not receive bethanechol. TBM was diagnosed by dynamic computography. Daily PSS was recorded for each infant from 40 to 55 weeks post-menstrual age. RESULTS: Cases' mean PSS change was 21% lower than the controls' mean PSS change pre- and post-bethanechol (95% CI -40%, -2%) by paired t-test (p = 0.03). Matched differences (controls' PSS - cases' PSS) demonstrated greater mean PSS difference post-bethanechol compared to pre-bethanechol 0.17, (95% CI 0.05, 0.29) by paired t-test (p = 0.009). CONCLUSION: Infants with TBM treated with bethanechol compared to those not treated had a lower PSS reflecting improved respiratory status.

Airway findings in trisomy 13 and trisomy 18: A 10-year retrospective review.

BACKGROUND AND OBJECTIVES: Trisomy 18 and trisomy 13 are the most common autosomal trisomies following trisomy 21, with overall incidence rising. Both diagnoses are characterized by multisystem involvement and were previously thought to be incompatible with life. New data suggest that prolonged survival is possible, and thus many families are opting for more aggressive medical interventions. This study aims to describe airway findings in trisomy 18 and trisomy 13, as these have not been comprehensively studied and can impact medical decision-making. We hypothesize that most children with trisomy 18 and trisomy 13 will have abnormal findings on airway endoscopy. METHODS: This a 10-year retrospective analysis of children with trisomy 13 or trisomy 18 who underwent endoscopic airway evaluation at a single center between 2011 and 2021. A total of 31 patients were evaluated. RESULTS: Thirty-one patients were included and underwent flexible bronchoscopy by a pediatric pulmonologist, often in conjunction with rigid bronchoscopy performed by pediatric otolaryngology. Findings were typically complimentary. All patients had at least one clinically significant finding on evaluation, and most patients had both upper and lower airway, as well as static and dynamic airway findings. The most common airway findings in children with trisomy 13 and 18 include tracheomalacia, bronchomalacia, laryngomalacia, hypopharyngeal collapse, glossoptosis, and bronchial compression. CONCLUSION: These findings can have significant implications for clinical care, and thus knowledge of trends has the potential to improve counseling on expected clinical course, presurgical planning, and informed consent before interventions.

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.

Open and Thoracoscopic Aortopexy for Airway Malacia in Children: 15 Year Single Centre Experience.

OBJECTIVES: The objective was to report and analyse the characteristics and results of open aortopexy and thoracoscopic aortopexy for the treatment of airway malacia in a paediatric population. METHODS: We report a retrospective consecutive case series of paediatric patients undergoing aortopexy for the treatment of airway malacia at a quaternary referral centre between December 2006 and January 2021. Outcome measures included days to extubation, continued need for non-invasive ventilation, further intervention in the form of tracheostomy and death. RESULTS: 169 patients underwent aortopexy: 147 had open procedures (135 via median/limited median sternotomy and 12 thoracotomy) and 22 thoracoscopic. Mean follow up was 8.46 yrs (range 1-20 yrs). Most common site of airway malacia was the trachea (n = 106, 62.7 %), and 48 (28.4 %) had additional involvement at the bronchi with tracheobronchomalacia (TBM). 15 (8.9 %) had bronchomalacia (BM) only. Incidence of bronchial disease was lower in the thoracoscopic than open group (13.6 % vs 40.82 %; p < 0.0001). Mean time to extubation was 1.45 days, 2.59 days, 5.23 days in tracheomalacia, TBM and BM groups, respectively (p = 0.0047). Mean time to extubation was 1.35 days, 2 days, 3.67 days, and 5 days in patients with external vascular compression, TOF/OA, primary airway malacia, and laryngeal reconstruction, respectively (p = 0.0002). There were 21 deaths across the cohort, and all were in the open group. 71.4 % (n = 15) had bronchial involvement of their airway malacia. CONCLUSIONS: Open and thoracoscopic aortopexy are effective treatments for airway malacia in children. We have identified that involvement of the bronchi is a risk factor for adverse outcomes, and the optimum treatment for this patient cohort is still debatable. LEVEL OF EVIDENCE: IV. TYPE OF STUDY: Retrospective Study.

Negative pressure suction test: An intraoperative airway maneuver to assess effectiveness of surgical correction of tracheobronchomalacia.

BACKGROUND: Surgical correction of tracheobronchomalacia (TBM) has evolved greatly over the past decade, with select pediatric institutions establishing dedicated surgery and anesthesia teams to navigate the complexities and challenges of surgical airway repairs. Although anesthetic techniques have evolved internally over many years to improve patient safety and outcomes, many of these methods remain undescribed in literature. TECHNIQUE: In this article, we describe the intraoperative negative pressure suction test. This simulates the negative pressure seen in awake and spontaneously breathing patients, including the higher pressures seen during coughing which induce airway collapse in patients with TBM. Also known as the Munoz maneuver in surgical literature, this test has been performed on over 300 patients since 2015. DISCUSSION: The negative pressure suction test allows for controlled intraoperative assessment of surgical airway repairs, replaces the need for risky intraoperative wake-up tests, increases the chances of a successful surgical repair, and improves anesthetic management for emergence and extubation. We provide a guide on how to perform the test and videos demonstrating its efficacy in intraoperative airway evaluation. CONCLUSIONS: As surgeries to repair TBM become more prevalent in other pediatric institutions, we believe that pediatric patients and anesthesia providers will benefit from the insights and methods described here.

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.

Thermoablative Techniques to Treat Excessive Central Airway Collapse.

Excessive central airway collapse (ECAC) is a condition characterized by the excessive narrowing of the trachea and mainstem bronchi during expiration, which can be caused by Tracheobronchomalacia (TBM) or Excessive Dynamic Airway Collapse (EDAC). The initial standard of care for central airway collapse is to address any underlying conditions such as asthma, COPD, and gastro-esophageal reflux. In severe cases, when medical treatment fails, a stent-trial is offered to determine if surgical correction is a viable option, and tracheobronchoplasty is suggested as a definitive treatment approach. Thermoablative bronchoscopic treatments, such as Argon plasma coagulation (APC) and laser techniques (potassium-titanyl-phosphate [KTP], holmium and yttrium aluminum pevroskyte [YAP]) are a promising alternative to traditional surgery. However, further research is needed to assess their safety and effectiveness in humans before being widely used.

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.

External airway splint placement for severe pediatric tracheobronchomalacia.

OBJECTIVE: To present external airway splinting with bioabsorbable airway supportive devices (ASD) for severe, life-threatening cases of pediatric tracheomalacia (TM) or tracheobronchomalacia (TBM). METHODS: A retrospective cohort was performed for 5 pediatric patients with severe TM or TBM who underwent ASD placement. Devices were designed and 3D-printed from a bioabsorbable material, polycaprolactone (PCL). Pre-operative planning included 3-dimensional airway modeling of tracheal collapse and tracheal suture placement using nonlinear finite element (FE) methods. Pre-operative modeling revealed that triads along the ASD open edges and center were the most effective suture locations for optimizing airway patency. Pediatric cardiothoracic surgery and otolaryngology applied the ASDs by suspending the trachea to the ASD with synchronous bronchoscopy. Respiratory needs were trended for all cases. Data from pediatric patients with tracheostomy and diagnosis of TM or TBM, but without ASD, were included for discussion. RESULTS: Five patients (2 Females, 3 Males, ages 2-9 months at time of ASD) were included. Three patients were unable to wean from respiratory support after vascular ring division; all three weaned to room air post-ASD. Two patients received tracheostomies prior to ASD placement, but continued to experience apparent life-threatening events (ALTE) and required ventilation with supraphysiologic ventilator settings. One patient weaned respiratory support successfully after ASD placement. The last patient died post-ASD due to significant respiratory co-morbidity. CONCLUSION: ASD can significantly benefit patients with severe, unrelenting tracheomalacia or tracheobronchomalacia. Proper multidisciplinary case deliberation and selection are key to success with ASD. Pre-operative airway modeling allows proper suture placement to optimally address the underlying airway collapse.

A novel ex vivo tracheobronchomalacia model for airway stent testing and in vivo model refinement.

OBJECTIVES: We sought to develop an ex vivo trachea model capable of producing mild, moderate, and severe tracheobronchomalacia for optimizing airway stent design. We also aimed to determine the amount of cartilage resection required for achieving different tracheobronchomalacia grades that can be used in animal models. METHODS: We developed an ex vivo trachea test system that enabled video-based measurement of internal cross-sectional area as intratracheal pressure was cyclically varied for peak negative pressures of 20 to 80 cm H2O. Fresh ovine tracheas were induced with tracheobronchomalacia by single mid-anterior incision (n = 4), mid-anterior circumferential cartilage resection of 25% (n = 4), and 50% per cartilage ring (n = 4) along an approximately 3-cm length. Intact tracheas (n = 4) were used as control. All experimental tracheas were mounted and experimentally evaluated. In addition, helical stents of 2 different pitches (6 mm and 12 mm) and wire diameters (0.52 mm and 0.6 mm) were tested in tracheas with 25% (n = 3) and 50% (n = 3) circumferentially resected cartilage rings. The percentage collapse in tracheal cross-sectional area was calculated from the recorded video contours for each experiment. RESULTS: Ex vivo tracheas compromised by single incision and 25% and 50% circumferential cartilage resection produce tracheal collapse corresponding to clinical grades of mild, moderate, and severe tracheobronchomalacia, respectively. A single anterior cartilage incision produces saber-sheath type tracheobronchomalacia, whereas 25% and 50% circumferential cartilage resection produce circumferential tracheobronchomalacia. Stent testing enabled the selection of stent design parameters such that airway collapse associated with moderate and severe tracheobronchomalacia could be reduced to conform to, but not exceed, that of intact tracheas (12-mm pitch, 0.6-mm wire diameter). CONCLUSIONS: The ex vivo trachea model is a robust platform that enables systematic study and treatment of different grades and morphologies of airway collapse and tracheobronchomalacia. It is a novel tool for optimization of stent design before advancing to in vivo animal models.