Tracheal Compression in a Patient with Marfan’s Syndrome-Associated Tracheomegaly Treated by an XXL Stent: The Largest Diameter Airway Stent Ever Placed in a Previously Undescribed Airway Condition

Micro-CT Imaging of Tracheal Development in Down Syndrome and Non-Down Syndrome Fetuses

OBJECTIVES

Down syndrome (DS) is associated with airway abnormalities including a narrowed trachea. It is uncertain whether this narrowed trachea in DS is a consequence of deviant fetal development or an acquired disorder following endotracheal intubation after birth. This study aimed to compare the tracheal morphology in DS and non-DS fetuses using microfocus computed tomography (micro-CT).

METHODS

Twenty fetal samples were obtained from the Dutch Fetal Biobank and divided into groups based on gestational age. Micro-CT images were processed to analyze tracheal length, volume, and cross-sectional area (CSA).

RESULTS

Mean tracheal length and tracheal volume were similar in DS and non-DS fetuses for all gestational age groups. Mean, minimum, and maximal tracheal CSA were statistically significantly increased in the single DS fetus in the group of 21-24 weeks of gestation, but not in other gestational age groups. In 90% of all studied fetuses, the minimum tracheal CSA was located in the middle third of the trachea.

CONCLUSION

Tracheal development in DS fetuses was similar to non-DS fetuses between 13 and 21 weeks of gestation. This suggests that the narrowed tracheal diameter in DS children may occur later in fetal development or results from postnatal intubation trauma. The narrowest part of the trachea is in majority of DS and non-DS fetuses the middle third.

LEVEL OF EVIDENCE

Level 3 Laryngoscope, 2024.

Coronavirus Disease 2019-Induced Tracheomegaly: A Case Report

Tracheomegaly is a medical condition where the tracheal diameter is greater than the upper limits of normal. Tracheomegaly can be classified as primary or secondary. Primary tracheomegaly is usually congenital. Secondary tracheomegaly can be due to multiple causes, including connective tissue disease, infections, autoimmune diseases like sarcoidosis, and prolonged mechanical ventilation. Here, we describe the first reported case of tracheomegaly secondary to coronavirus disease 2019 (COVID-19) pneumonia and COVID-induced interstitial lung disease (ILD). While many cases of tracheomegaly are asymptomatic, patients can have symptoms like cough, dyspnea, hemoptysis, or even respiratory failure. Tracheomegaly is associated with a higher risk of recurrent lower respiratory tract infections, chronic cough, bronchiectasis, and tracheobronchomalacia. Early recognition of COVID-19-induced tracheomegaly can help initial early management and reduce the incidence of infections.

The Thoracic Inlet Index in patients with tracheal obstruction caused by chest wall deformity: Validation in patients and age-matched controls

AIM

We present a novel index for evaluating severity of airway-threatening thoracic inlet compromise in childhood. Two indices were validated in three cases and sixty asymptomatic controls.

METHODS

We developed an index to determine severity of thoracic inlet narrowing. Two different measurement methods were evaluated: Thoracic Inlet Index (TII) was determined at the site of greatest airway compromise at the level of the innominate artery crossing the anterior trachea and TII (anatomic) using purely skeletal measurements, both determined from thoracic CT scan. We sought to validate both indices to determine which was more predictive of the risk of airway compromise. Three patients who presented with life threatening airway compromise were compared to sixty age matched asymptomatic controls obtained from the trauma registry.

RESULTS

The mean TII in controls was 3.89. The TII was consistent at various ages. In patients, mean TII was 12.16 (range of 11.31-12.95). For TII the difference between controls and symptomatic patients was highly significant (P=0.0012). The mean TII (anatomic) in controls was 3.5. The TII (anatomic) was less consistent when evaluated in different age groups. In patients mean TII (anatomic) was 6.32 (range 5.38-7.59). For TII (anatomic), the difference between controls and symptomatic patients was also significant (P=0.0474) but did not discriminate as well as the functional index.

CONCLUSIONS

The TII measured at the level of the innominate artery crossing on thoracic CT scan appears to be the most useful. A level of greater than 10 was highly predictive of airway compromise in our patient group.

A Clinical Classification Scheme for Tracheobronchomegaly (Mounier-Kuhn Syndrome)

INTRODUCTION

Tracheobronchomegaly (Mounier-Kuhn Syndrome) is a rare disease characterized by tracheal enlargement and associated loss of elastic fibers in the trachea and main bronchi.

MATERIALS

MEDLINE, Index Medicus, and other databases were searched with pre-defined criteria to identify cases of tracheobronchomegaly (TBM). Two new cases of TBM were also identified from the Provincial Medical Genetics Program of British Columbia.

RESULTS

We identified 166 publications describing 365 occurrences of TBM. We observed that affected individuals could be grouped into subgroups according to clinical features. Type 1A (105 individuals) consists of infants who developed TBM after having undergone fetoscopic tracheal occlusion, and Type 1B patients (24 individuals) are infants and children who developed TBM after prolonged intubation. Type 2 individuals developed TBM following recurrent pulmonary infections (2A) (14 individuals) or pulmonary fibrosis (2B) (10 individuals). Type 3 represents TBM with evidence of extra-pulmonary elastolysis (18 individuals), and Type 4 denotes the development of TBM with no clear predisposing factors (196 individuals). Both of our patients had TBM and evidence of extra-pulmonary elastolysis. As well, one patient had a mildly dilated aortic root, which is a previously unreported co-occurrence.

CONCLUSION

We introduce a novel classification scheme, which may sort patients into etiologically distinct groups, furthering our understanding of its pathogenesis and potentially, prevention or therapy. We also hypothesize that TBM and generalized elastolysis may have etiological commonalities, suggesting a need for further study.

Tracheomalacia treatment using a large-diameter, custom-made airway stent in a case with mounier-kuhn syndrome

Mounier-Kuhn Syndrome (MKS) is a rare congenital disease that presents with abnormal enlargement in the central airways. In MKS, tracheomegaly is accompanied by difficulty in expelling recurrent lung infections and bronchiectasia. We presented a patient with MKS where commercially made stents were inadequate for stabilization and a custom-made, self-expandable metallic stent with a diameter of 28 mm and length of 100 mm was used. Chest pain that was thought to develop due to the stent and that disappeared after stent removal may be considered the main complication leading to stent removal. Continuous positive airway pressure therapy (CPAP) therapy was planned for the control of symptoms, which re-emerged after stent removal. This case is presented as an example that complications developing due to the stent as well as patient noncompliance may lead to stent removal, even when useful results are obtained from treatment of MKS.

The use of self-expandable metallic stents in the airways in the adult population

The airway stents restore patency in the face of luminal compromise from intrinsic and/or extrinsic pathologies. Luminal compromise beyond 50% often leads to debilitating symptoms such as dyspnea. Silicone stents remain the most commonly placed stents worldwide and have been the "gold standard" for the treatment of benign and malignant airway stenoses over the past 20 years. Nevertheless, silicone stents are not the ideal stents in all situations. Metallic stents can serve better in some selected conditions. Unlike silicone stents, there are large and increasing varieties of metallic stents available on the market. The lack of prospective or comparative studies between various types of metallic stents makes the choice difficult and expert-opinion based. International guidelines are sorely lacking in this area.