Current concepts in severe adult tracheobronchomalacia: evaluation and treatment

Thoracoscopic plication of the membranous portion of crescent-type tracheobronchomalacia in an elderly patient: a case report

Background

It is presumed that tracheobronchomalacia in adults is caused by airway pressure-induced injury due to chronic cough related to pulmonary emphysema or chronic bronchitis. Commonly, a posterolateral approach using stabilizing materials is the surgical technique of choice for treating tracheobronchomalacia. We report a case in which thoracoscopic plication of the membranous portion was performed instead of airway stent placement for tracheobronchomalacia in an elderly individual.

Case presentation

An 87-year-old man who had been treated for bronchial asthma, pulmonary emphysema, and tracheobronchomalacia was admitted to our hospital with acute exacerbation of dyspnea. The patient underwent tracheal intubation, which was followed by tracheostomy 16 days later. Insertion of the tip of the adjustable-length tracheostomy tube to the end of the stenotic lesion enabled him to breathe spontaneously. However, conservative management failed due to recurrent pneumonia caused by the tracheobronchomalacia. Crescent-type tracheobronchomalacia (Johnson’s classification grade III) was diagnosed, and the main narrowed area of the trachea was assumed to be approximately 3–10 cm from the tracheal bifurcation. A thoracoscopic approach was selected because a posterolateral approach was considered too invasive considering the patient’s age and general condition. We placed eight stitches on the tracheal membranous portion and four stitches on the membranous portion of the right main bronchus, using the horizontal mattress suture technique. The use of foreign materials was avoided because meropenem-resistant Pseudomonas aeruginosa was cultured in a tracheal specimen. Immediately after the operation, the expiratory airway stenosis improved, and subsequently, spontaneous ventilation was possible using a normal type of tracheostomy tube instead of an adjustable-length tracheostomy tube.

Conclusions

Tracheobronchomalacia is not a rare condition in patients with chronic obstructive pulmonary disease. The thoracoscopic approach is less invasive than the posterolateral approach and is suitable in cases that are otherwise refractory to medical treatment. We believe that thoracoscopy may be a useful treatment option in cases where conservative treatment is not appropriate.

Airway stenting: Technological advancements and its role in interventional pulmonology

AS offers rapid and sustained relief of symptoms in most patients treated for malignant or benign CAO and can also be curative in itself in cases of benign tracheobronchial stenosis. In the past 30 years, this field has seen significant progress, from the misuse of vascular non-covered metallic stents to the development of silicone airway stents with an increasingly large panel of shapes and of hybrid, partially or fully covered, SEMS customized to the airways. This study aims to offer an overview on: (i) the respective advantages and drawbacks of these two main categories of devices; (ii) the main indications for AS and the rationale behind the choice of stent in each situation; and (iii) the main promises borne from the progress made in the field in the past few years, including the development of drug-eluting, biodegradable or patient-specific customized AS.

Arterial blood gas analysis in dogs with bronchomalacia

Canine bronchomalacia (CBM) is a structural airway disease leading to chronic cough and intermittent respiratory distress, primarily affecting elderly dogs of small breeds. Results of blood gas analysis have been reported in dogs with several diseases, but not yet in those with CBM. Eleven dogs with CBM were recruited in this study. Most dogs presented with mild hypoxemia and normocapnia, and all with increased alveolar-arterial difference for O₂ (A-aDO₂). In computed tomography, abnormal lung patterns, such as atelectasis and parenchymal band, were detected in all dogs, consistent with the regions affected by CBM. We conclude that CBM causes abnormal lung patterns and results in impaired oxygenation. Blood gas analysis is a useful tool for detecting mild pulmonary lesions and concurrent CBM.

In vivo dynamics of the tracheal airway and its influences on respiratory airflows

Respiration is a dynamic process accompanied by morphological changes in the airways. Although deformation of large airways is expected to exacerbate pulmonary disease symptoms by obstructing airflow during increased minute ventilation, its quantitative effects on airflow characteristics remain unclear. Here, we used an exemplar case derived from in vivo dynamic imaging and examined the effects of tracheal deformation on airflow characteristics under different conditions. First, we measured tracheal deformation profiles of a healthy lung using magnetic resonance imaging during forced exhalation, which we simulated to characterize subject-specific airflow patterns. Subsequently, for both inhalation and exhalation, we compared the airflows when the maximal deformation in tracheal cross-sectional area was 0% (rigid), 33% (mild), 50% (moderate), or 75% (severe). We quantified differences in airflow patterns between deformable and rigid airways by computing the correlation coefficients (R) and the root-mean-square of differences (Drms) between their velocity contours. For both inhalation and exhalation, airflow patterns were similar in all branches between the rigid and mild conditions (R > 0.9; Drms < 32%). However, airflow characteristics in the moderate and severe conditions differed markedly from those in the rigid and mild conditions in all lung branches, particularly for inhalation (moderate: R > 0.1, Drms < 76%; severe: R > 0.2, Drms < 96%). Our exemplar case supports the use of a rigid airway assumption to compute flows for mild deformation. For moderate or severe deformation, however, dynamic contraction should be considered, especially during inhalation, to accurately predict airflow and elucidate the underlying pulmonary pathology.

Treatment of complex airway stenoses using patient-specific 3D-engineered stents: a proof-of-concept study

Anatomically complex airway stenosis (ACAS) represents a challenging situation in which commercially available stents often result in migration or granulation tissue reaction due to poor congruence. This proof-of-concept clinical trial investigated the feasibility and safety of computer-assisted designed (CAD) and manufactured personalised three-dimensional (3D) stents in patients with ACAS from various origins. After CAD of a virtual stent from a CT scan, a mould is manufactured using a 3D computer numerical control machine, from which a medical-grade silicone stent is made. Complication rate, dyspnoea, quality of life and respiratory function were followed after implantation. The congruence of the stent was assessed peroperatively and at 1 week postimplantation (CT scan). The stent could be implanted in all 10 patients. The 3-month complication rate was 40%, including one benign mucus plugging, one stent removal due to intense cough and two stent migrations. 9 of 10 stents showed great congruence within the airways, and 8 of 10 induced significant improvement in dyspnoea, quality of life and respiratory function. These promising outcomes in highly complex situations support further investigation on the subject, including technological improvements.​ TRIAL REGISTRATION NUMBER: NCT02889029.

Ultralow Dose Dynamic Expiratory Computed Tomography for Evaluation of Tracheomalacia

OBJECTIVE

The aim of this study was to determine the average effective radiation dose and feasibility of ultralow dose dynamic expiratory computed tomography (CT) for evaluation of tracheomalacia (ULD) and to evaluate factors that impact image quality.

METHODS

This is a retrospective study of 64 consecutive patients from September to October 2016 for the evaluation of tracheomalacia. All studies were performed with routine inspiration chest CT followed by ULD z(kilovoltage peak (kVp) 80, 100, or 120 and fixed milliamperage 10) or typical dose CT (TD) (kVp 100 or 120 with automated milliamperage) dynamic expiration CT. Image quality was considered diagnostic if the trachea area could be accurately measured for tracheomalacia assessment, and diagnostic studies were graded fair, good, or excellent. Scan length, image quality, and effective radiation dose were compared for ULD versus TD and ULD at 100 kVp versus ULD at 80 kVp. For ULD studies, patient factors were compared across image quality.

RESULTS

The ULD had a mean effective radiation dose of 0.08 mSv, with all studies of diagnostic image quality. The ULD showed 95% reduction in effective radiation dose (P < 0.001), 14% significant reduction in scan length (P = 0.029), and qualitatively decreased image quality compared w2 ith TD (P < 0.001). The ULD at 100 kVp had significantly better image quality compared with ULD at 80 kVp (P = 0.041) with higher effective radiation dose (0.09 vs 0.05 mSv) (P < 0.001). Body mass index significantly impacted image quality for all ULD studies but not for ULD at 80 or 100 kVp.

CONCLUSION

For evaluation of tracheomalacia, ULD showed low effective radiation dose less than 0.1 mSv and maintained diagnostic image quality.

First series of minimally invasive, robot-assisted tracheobronchoplasty with mesh for severe tracheobronchomalacia

OBJECTIVE

Tracheobronchomalacia is a progressive, debilitating disease with limited treatment options. Open tracheobronchoplasty (TBP) is an accepted surgical option for management of severe tracheobronchomalacia. This study examined the outcomes of the first reported series of robot-assisted TBP (R-TBP).

METHODS

We retrospectively reviewed the records of patients with clinical suspicion for tracheobronchomalacia who had dynamic computed tomography scan and subsequent R-TBP from May 2016 to December 2017.

RESULTS

Four hundred thirty-five patients underwent dynamic computed tomography scan for suspicion of tracheobronchomalacia. Of this group, 42 patients underwent R-TBP. In the surgery group, the median age was 66 years (interquartile range, 39-72 years) and there were 30 women (71%). Respiratory comorbidities included asthma (88%) and chronic obstructive pulmonary disease (52%). The median operative time was 249 minutes (interquartile range, 266-277 minutes). Median hospital length of stay was 3 days (interquartile range, 2-4.75 days), and there were 19 postoperative complications (11 minor and 8 major). There were no mortalities at 90 days. Comparison of preoperative and postoperative pulmonary function testing demonstrated improvement in forced expiratory volume at 1 second by 13.5% (P = .01), forced vital capacity by 14.5% (P < .0001), and peak expiratory flow rate by 21.0% (P < .0001). Quality of life questionnaires also showed improvement with 82% reporting overall satisfaction with the procedure.

CONCLUSIONS

R-TBP can be performed with low morbidity and mortality. Early follow-up reveals significant improvement in pulmonary function testing and high patient satisfaction when compared with preoperative baseline. Long-term follow-up is needed to demonstrate the durability of R-TBP and substantiate its role in the management of patients with symptomatic, severe tracheobronchomalacia.

Improving Quality of Dynamic Airway Computed Tomography Using an Expiratory Airflow Indicator Device

PURPOSE

Dynamic computed tomography (CT) of the airways is increasingly used to evaluate patients with suspected expiratory central airway collapse, but current protocols are susceptible to inadequate exhalation caused by variable patient compliance with breathing instructions during the expiratory phase. We developed and tested a low-cost single-use expiratory airflow indicator device that was designed to improve study quality by providing a visual indicator to both patient and operator when adequate expiratory flow was attained.

MATERIALS AND METHODS

A total of 56 patients undergoing dynamic airway CT were evaluated, 35 of whom were scanned before introduction of the indicator device (control group), with the rest comprising the intervention group. Lung volumes and tracheal cross-sectional areas on inspiratory/expiratory phases were computed using automated lung segmentation and quantitative software analysis. Inadequate exhalation was defined as absolute volume change of <500 mL during the expiratory phase.

RESULTS

Fewer patients in the intervention group demonstrated inadequate exhalation. The average change in volume was higher in the intervention group (P=0.004), whereas the average minimum tracheal cross-sectional area was lower (P=0.01).

CONCLUSIONS

The described expiratory airflow indicator device can be used to ensure adequate exhalation during the expiratory phase of dynamic airway CT. A higher frequency of adequate exhalation may improve reliability and sensitivity of dynamic airway CT for diagnosis of expiratory central airway collapse.

The utility of 3D-printed airway stents to improve treatment strategies for central airway obstructions

Airway stents are commonly used in the management of patients suffering from central airway obstruction (CAO). CAO may occur directly from airway strictures, obstructing airway cancers, airway fistulas or tracheobronchomalacia, resulting from the weakening and dynamic collapse of the airway wall. Current airway stents are constructed from biocompatible medical-grade silicone or from a nickel-titanium (nitinol) alloy with fixed geometry. The stents are inserted via the mouth during a bronchoscopic procedure. Existing stents have many shortcomings including the development of obstructing granulation tissue in the weeks and months following placement, mucous build up within the stent, and cough. Furthermore, airway stents are expensive and, if improperly sized for a given airway, may be easily dislodged (stent migration). Currently, in Australia, it is estimated that approximately 12,000 patients will develop CAO annually, many of whom will require airway stenting intervention. Of all stenting procedures, the rate of failure is currently reported to be at 22%. With a growing incidence of lung cancer prevalence globally, the need for updating airway stent technology is now greater than ever and personalizing stents using 3D-printing technology may offer the best chance of addressing many of the current limitations in stent design. This review article will assess what represents the gold standard in stent manufacture with regards to treatment of tracheobronchial CAO, the challenges of current airway stents, and outlines the necessity and challenges of incorporating 3D-printing technology into personalizing airway stents today.

A Case of Tracheomalacia in Chronic Obstructive Pulmonary Disease: What Went Wrong?

Tracheobronchomalacia is defined as loss of the structural integrity of airway wall cartilaginous structures with hyperdynamic airway collapse during respiration. It is a common finding in chronic obstructive pulmonary disease (COPD) but is not always symptomatic, especially if airway narrowing is mild. Symptoms and signs develop as the severity of airway narrowing progresses. When a patient is symptomatic, a prompt study with computerized tomography and flexible bronchoscopy is mandatory for future management. We present a case of tracheobronchomalacia in a patient with COPD whose diagnosis and treatment were challenging.

Frailty Characteristics Predict Respiratory Failure in Patients Undergoing Tracheobronchoplasty

BACKGROUND

Respiratory complications are the leading cause of morbidity in patients undergoing tracheobronchoplasty, yet risk stratification systems on this population are insufficient. We investigated the association between frailty and risk of major respiratory complications after tracheobronchoplasty.

METHODS

A retrospective review was made of 161 consecutive tracheobronchoplasties (October 2002 to September 2016). A frailty index was developed by the deficit-accumulation approach comprising 26 multidomain preoperative variables. The main outcome was a composite endpoint of major respiratory complications within 30 days of surgery. Odds ratio (OR) and 95% confidence interval (CI) were estimated using logistic regression.

RESULTS

The cohort consisted of 103 women (64%), median age of 58 years (interquartile range, 51 to 66) and median FI of 0.25 (interquartile range, 0.1 to 0.3). Forty-eight patients (30%) had respiratory complications, the most common being respiratory failure (n = 27, 16.8%) and pneumonia (n = 25, 15.5%). Severe frailty (frailty index ≥0.33) was strongly associated with major respiratory complications (73.8% versus 2.5%; OR 58.8, 95% CI: 9.6 to 358.3). The association with severe frailty appeared stronger for respiratory failure (47.6% versus 2.5%; OR 30, 95% CI: 4.7 to 189.9) than for pneumonia (40.5% versus 0%; OR 35.2. 95% CI: 2.0 to 599.8). Further adjustment for intraoperative crystalloid volume or forced expiratory volume in 1 second moderately attenuated the association between frailty with major respiratory complications (OR 17.4. 95% CI: 2.0 to 150.8), respiratory failure (OR 13.1, 95% CI: 1.7 to 95.8), and pneumonia (OR 20.1, 95% CI: 1.1 to 341.8).

CONCLUSIONS

Frailty, as indicated by frailty index, was associated with major respiratory complications, particularly respiratory failure after tracheobronchoplasty. Preoperative identification of frailty may help guide decision making for patients considering this effective, although arduous procedure.

Post-intubation tracheobronchomalacia in a young adult: A rare case report

Tracheobronchomalacia (TBM) is characterized by weakness of cartilaginous supporting structures of tracheal and bronchial walls, resulting in central airway obstruction. It is a rare condition that can occur after prolonged intubation. Here, we report a 26-year-old, alcoholic male who had TBM, mild subglottic, and severe tracheal stenosis following 2 weeks of intubation.

Subglottic and tracheal stenosis can occur after extubation but TBM is uncommon. The exact mechanism is still unknown but post-intubation TBM is a life-threatening condition with high morbidity and mortality if left untreated. Early detection and timely management can improve the outcome of patients.

Tracheobronchoplasty for tracheomalacia

Tracheobronchomalacia is an uncommon acquired disorder of the central airways. Common symptoms include dyspnea, constant coughing, inability to raise secretions and recurrent respiratory infections. Evaluation includes an inspiratory-expiratory chest computed tomography (dynamic CT), an awake functional bronchoscopy and pulmonary function studies. Patients with significant associated symptoms and severe collapse on CT and bronchoscopy are offered membraneous wall plication. Tracheobronchoplasty is performed through a right thoracotomy. The posterior airway is exposed after the azygous vein is ligated. The posterior wall of the trachea (and usually both main bronchi) is plicated to a sheet of thick acellular dermis (or polypropylene mesh) with a series of 4 mattress sutures of 4-0 sutures from the thoracic inlet to the bottom of the trachea to re-shape the trachea and restore the normal D shape. Patients report generally good results with improvement of their symptoms. Quality of life is usually improved while pulmonary function tests usually are not improved.

Recurrent dyspnea and wheezing- pulmonary function test and dynamic computed tomography may unfold the diagnosis of tracheobronchomalacia

Tracheomalacia patients often present with nonspecific symptoms like cough, wheezing and dyspnea. Tracheomalacia diagnosis is usually attributed to alternative common conditions such as asthma or chronic obstructive lung disease. Certain maneuvers, like forced expiration, or recumbent position may elicit subtle signs of tracheomalacia. Ordering novel pulmonary function testing in sitting upright and supine positions may provide additional clues to suspect tracheomalacia, which can be confirmed by either dynamic chest tomography or bronchoscopy.