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.

Diagnostic accuracy of imaging compared to histology in congenital lung malformations.

INTRODUCTION: The aim of this study was to evaluate the accuracy of imaging tests (prenatal ultrasound [US] and postnatal computed tomography [CT]) in comparison to histology for diagnosis of congenital lung malformations (CLMs). MATERIAL AND METHODS: Retrospective study of patients with a prenatal diagnosis of CLM whose postnatal follow-up included thoracic CT scan and histological examination of the lesion. We collected data on demographic variables, gestational age at diagnosis, US findings and the history of multiple gestation. We used the kappa coefficient to determine the level of agreement between the findings of prenatal US and postnatal tests (CT and histology).We analysed paired data on the size of the lesion, its location and the presence or absence of systemic arterial vascularization. RESULTS: The sample included 56 patients with 57 lesions. The mean gestational age at diagnosis was 22.42 weeks (SD, 3.94) and 57% were male. Malformations most frequently involved the left lung and the lower lobes. The agreement between CT and histology in the detection of cystic lesions was moderate (κ = 0.55) but stronger compared to the agreement between US and histology (κ = 0.10). The agreement between CT and histology was substantial (κ = 0.66) in the detection of systemic vascularization of the lesion and stronger compared to the agreement between US and histology. Both imaging methods were highly accurate in the identification of the location of the pulmonary lesions. CONCLUSIONS: postnatal CT offers a substantial concordance with histological findings, especially in the detection of systemic vascularization, and an accurate prediction of the anatomy of the lesion.

Histological and structural effects of biodegradable polydioxanone stents in the rabbit trachea.

OBJECTIVES: The aim of this study was to evaluate the potential biologic effects caused by the successive placement of biodegradable polydioxanone (PDO) stents in the rabbit trachea. PDO stents could eventually induce a fibroproliferative reaction in the submucosa that could be beneficial in the treatment of malacia due to an increase in its consistency without impairing the tracheal lumen. METHODS: Sixteen adult NZ rabbits were distributed into 3 groups with different survival times according to the number of stents placed: 1 stent (14 weeks), 2 stents (28 weeks) and 3 stents (42 weeks). Stent insertion was performed endoscopically in the cervical trachea of the animal. Histopathological studies included Masson's trichrome staining for submucosal fibrosis and Safranin O to assess the structural integrity of cartilage. Potential inflammatory changes were analysed by means of immunohistochemistry determining the number of CD45-positive cells. RESULTS: Stent placement was successful in every case. Histological studies did not show a statistically significant increase in tracheal wall collagen area and cartilage structure was not modified in those rabbits with 1 or more PDO stents inserted compared to non-stented tracheal sections. Furthermore, no statistically significant changes in the number of CD45+ cells were observed in stented tracheal segments compared to normal tracheal tissues. CONCLUSIONS: According to our data, successive PDO stenting caused mild inflammatory changes in the tracheal wall and no increase in the collagen matrix, and the cartilaginous support was not modified during a long follow-up period (up to 42 weeks). These findings suggest that they may be safe and show good biocompatibility in the long term.

Foreign body aspiration in children: Treatment timing and related complications.

BACKGROUND/PURPOSE: The aims of this study were to describe our experience in the management of FB aspiration in children, focusing on the eventual association between delay in treatment and the development of complications, and to determine if the incidence of this emergency had decreased in the last 10 years. METHODS: Retrospective study of children with a diagnosis of FB aspiration managed between 1999 and 2019 at a tertiary care referral hospital. The following data were collected: demographics, clinical presentation, radiological findings, endoscopic technique, type of FB, time elapsed between the aspiration episode and treatment, and complications. Main outcome measures were the rate of complications (intraoperative and long-term) in the cohort of patients with delay in treatment (>72 h), and the incidence of FB aspiration in each of the two historical subgroups of the study. RESULTS: The study included 130 patients, 66.2% male, with a median age of 24 months. Cough was the most frequent symptom (76.1%) and unilateral air trapping was the most common radiological finding (48.8%). Removal of FB was performed with rigid bronchoscopy in every case. The most common type of FB was organic (73%) and located in the right bronchial system (47.7%). The global rate of complications was 16.1%. Patients with a delay in treatment beyond 72 h from the aspiration episode showed a statistically significant risk of developing both intraoperative and postoperative complications. Additionally, we have stated that the incidence of FB aspiration in our community has decreased by 44.4% in the last 10 years. CONCLUSIONS: The incidence of FB aspiration has remarkably decreased in our environment in the last decade. Delay in treatment placed our patients at a significant higher risk of developing complications both during the bronchoscopic procedure and in the long-term.

Vocal cord paralysis after cardiovascular surgery in children: incidence, risk factors and diagnostic options.

OBJECTIVES: The aim of this study was to assess the incidence of vocal cord paralysis (VCP) in children after cardiovascular surgery. The secondary aims were to identify the factors potentially associated with VCP and to assess the diagnostic utility of laryngeal ultrasound (US). METHODS: This study is a retrospective review of patients who underwent aortic repair, patent ductus arteriosus ligation and left pulmonary artery surgeries from 2007 to 2017. The following data were collected: patient demographics, gestational age, weight and age at surgery, comorbidities, cardiovascular anomaly and type of procedure, laryngoscopic and US evaluation results. Univariable and multivariable logistic regression models were used to identify the variables associated with VCP. RESULTS: Two hundred and six patients were included in the study. Seventy-two patients (35%) were preterm and 32.5% showed comorbidities. At surgery, median age and weight were 0.6 months [interquartile range (IQR) 0.3-2.1] and 3.0 kg (IQR 1.3-4.0), respectively. Postoperatively, symptomatic patients underwent endoscopic evaluation and VCP was detected in 25 cases (12.1%). Laryngeal US was performed in 8 of these showing an excellent diagnostic relationship. On univariable analysis, factors significantly associated with VCP were prematurity, young age and lower weight at surgery and the presence of comorbidities. The presence of comorbidities and weight at surgery exhibited a significant risk of developing VCP postoperatively on multivariable analysis. CONCLUSIONS: VCP is not an unusual complication of cardiovascular surgery. Certain factors were associated with VCP development but only the presence of comorbidities and weight at surgery were statistically significant on multivariable analysis. Flexible laryngoscopy is the standard diagnostic technique and laryngeal US appears to be a reliable complement.

Spanish multicentre study on morbidity and pathogenicity of tracheal bronchus in children.

Tracheal bronchus (TRB) has been generally considered an anatomical variant of the tracheobronchial tree without a precise pathological effect. Its prevalence is estimated to be between 0.2% to 3% of all children undergoing bronchoscopy and scientific information has been limited to case reports or small case series. Our working hypothesis was that TRB could trigger by itself recurrent or persistent respiratory symptoms. The objective of this retrospective and multicentre study of children with a diagnosis of TRB, coming from the main paediatric pulmonology units of Spain, was to determine the anatomical and clinical characteristics, including comorbidities, of TRB in childhood and their impact in the patients' clinical outcomes. One hundred thirty-three patients from 13 institutions were included in the study. Mean diagnostic age was 3.4 years and flexible bronchoscopy was the initial diagnostic method in 85% of cases. All TRB were located on the right wall of the trachea: 76% in the lower third and 24% in the carina. The most common clinical manifestations were obstructive bronchitis (53.3%) and recurrent pneumonia (46.6%), usually affecting the right upper lobe. Regarding associated anomalies, 33% had tracheomalacia, 32% congenital cardiovascular malformations, 28% gastroesophageal reflux, 22.5% congenital tracheal stenosis, and 8.3% Down syndrome. This series appears to be the most extensive published to date addressing this topic and, according to our data, TRB does not appear to be a mere incidental finding but is more likely linked to a wide range of congenital anomalies and contributes by itself to the recurrent respiratory symptomatology that these children exhibit.

ERS statement on tracheomalacia and bronchomalacia in children.

Tracheomalacia and tracheobronchomalacia may be primary abnormalities of the large airways or associated with a wide variety of congenital and acquired conditions. The evidence on diagnosis, classification and management is scant. There is no universally accepted classification of severity. Clinical presentation includes early-onset stridor or fixed wheeze, recurrent infections, brassy cough and even near-death attacks, depending on the site and severity of the lesion. Diagnosis is usually made by flexible bronchoscopy in a free-breathing child but may also be shown by other dynamic imaging techniques such as low-contrast volume bronchography, computed tomography or magnetic resonance imaging. Lung function testing can provide supportive evidence but is not diagnostic. Management may be medical or surgical, depending on the nature and severity of the lesions, but the evidence base for any therapy is limited. While medical options that include bronchodilators, anti-muscarinic agents, mucolytics and antibiotics (as well as treatment of comorbidities and associated conditions) are used, there is currently little evidence for benefit. Chest physiotherapy is commonly prescribed, but the evidence base is poor. When symptoms are severe, surgical options include aortopexy or posterior tracheopexy, tracheal resection of short affected segments, internal stents and external airway splinting. If respiratory support is needed, continuous positive airway pressure is the most commonly used modality either via a face mask or tracheostomy. Parents of children with tracheobronchomalacia report diagnostic delays and anxieties about how to manage their child's condition, and want more information. There is a need for more research to establish an evidence base for malacia. This European Respiratory Society statement provides a review of the current literature to inform future study.

Laryngeal stenosis in children: Types, grades and treatment strategies.

INTRODUCTION: Laryngeal stenosis is infrequent in children and usually secondary to endotracheal intubation. The aims of this study were to review the outcomes of the distinct endoscopic and surgical procedures and to suggest a technical modification for one of them. METHODS: Retrospective review of patients with the diagnosis of laryngeal stenosis treated in an academic tertiary care institution between 2000 and 2017. The following variables were analyzed: demographic data, endoscopic findings including anatomic type and severity of the lesion, associated anomalies, type of treatment, outcomes, and time of follow-up. RESULTS: Seventy-eight children were included in the study (39 boys) with a median age at diagnosis of 9 months, and 33 (42.3%) showed an associated anomaly. Lesions were acquired in 84.6% of cases and the subglottic region was most frequently involved (77%). Thirty patients (38.4%) had a severe stenosis (Myer-Cotton grades III and IV) and a tracheotomy was performed as an initial treatment in 38 patients (48.7%). Overall, 91% of endoscopically or surgically treated patients showed a good outcome and the decannulation rate in the series was 79.4%. Fourteen patients were managed conservatively. Median follow-up was 29 months (I.R. 10-60 m.) CONCLUSIONS: Laryngeal stenosis in children is usually acquired and exhibit a wide range of anatomic presentations. Endoscopic therapeutic procedures may be useful in the management of low grade immature stenosis. Reconstructive surgical techniques may provide a high success rate with an appropriate selection of candidates.

ERS statement: interventional bronchoscopy in children.

Paediatric airway endoscopy is accepted as a diagnostic and therapeutic procedure, with an expanding number of indications and applications in children. The aim of this European Respiratory Society task force was to produce a statement on interventional bronchoscopy in children, describing the evidence available at present and current clinical practice, and identifying areas deserving further investigation. The multidisciplinary task force panel performed a systematic review of the literature, focusing on whole lung lavage, transbronchial and endobronchial biopsy, transbronchial needle aspiration with endobronchial ultrasound, foreign body extraction, balloon dilation and occlusion, laser-assisted procedures, usage of airway stents, microdebriders, cryotherapy, endoscopic intubation, application of drugs and other liquids, and caregiver perspectives. There is a scarcity of published evidence in this field, and in many cases the task force had to resort to the collective clinical experience of the committee to develop this statement. The highlighted gaps in knowledge underline the need for further research and serve as a call to paediatric bronchoscopists to work together in multicentre collaborations, for the benefit of children with airway disorders.

TGF-ß antagonist attenuates fibrosis but not luminal narrowing in experimental tracheal stenosis.

OBJECTIVE: Acquired tracheal stenosis (ATS) is an unusual disease often secondary to prolonged mechanical trauma. Acquired tracheal stenosis pathogenesis involves inflammation and subsequent fibrosis with narrowing of the tracheal lumen. Transforming growth factor-ß1 (TGF-ß) represents a pivotal factor in most fibrotic processes, and therefore a potential target in this context. The aim of this study is to analyze the role of TGF-ß as a target for anti-fibrotic interventions in tracheal stenosis. METHODS: Human stenotic tracheobronchial tissues from patients with benign airway stenosis and normal controls from pneumonectomy specimens were analyzed. Tracheal stenosis was induced in adult NZ rabbits by a circumferential thermal injury to the mucosa during open surgery and re-anastomosis. Rabbits were treated postoperatively with a peritracheal collagen sponge containing a TGF-ß peptide antagonist (p17) or vehicle. Fibrosis was determined by Masson's trichrome staining, and smooth muscle cell α-actin+ (α-SMA+ Confirm accuracy.) myofibroblasts, connective tissue growth factor (CTGF), and p-Smad2/3 expression by immunohistochemistry. RESULTS: Human and rabbit stenotic tissues showed extensive submucosal fibrosis, characterized by significantly increased α-SMA+ myofibroblasts and CTGF expression. In human stenotic lesions, increased p-Smad2/3+ nuclei were also observed. p17 treatment significantly reduced the fibrotic thickness, as well as the density of α-SMA+ myofibroblasts and CTGF+ cells in rabbit stenotic lesions, but failed to improve the luminal area. CONCLUSION: ATS is characterized by a TGF-ß dependent fibrotic process, but reduction of the fibrotic component by TGF-ß1 antagonist therapy was not sufficient to improve tracheal narrowing, suggesting that fibrosis may not be the main contributor to luminal stenosis. LEVEL OF EVIDENCE: NA. Laryngoscope, 127:561-567, 2017.

Tracheobronchial stents in children.

Tracheobronchial obstruction is infrequent in children and still remains a challenging matter of concern. Management alternatives vary from conservative treatment to complex surgical techniques or endoscopic interventional procedures. Airway stenting in children is relatively recent and follows the trail of the experience in adult patients. Nevertheless, there are basic differences between both age groups like the benign nature of most obstructions and the small size of the pediatric airway. These specific features raise the issues of the precise role of tracheobronchial stenting in children and the selection of the most adequate device. Stents fall into four main categories according to the material they are made of: metallic, plastic, hybrid, and biodegradable. Each type has its own advantages and drawbacks so the ideal stent is not yet available. Despite increasing experience with stenting, definite clinical criteria for their use in children are yet to be established. Even so, there seems to be a basic general agreement that stents may play a role in particular clinical settings in which there are no other therapeutic options.

Initial experience with a new biodegradable airway stent in children: Is this the stent we were waiting for?

OBJECTIVE: To report our experience with a new type of biodegradable airway stent in the setting of severe tracheobronchial obstruction in children. DESIGN AND METHODOLOGY: We conducted a retrospective and prospective (since June 2014) study of pediatric patients with severe airway obstruction treated with biodegradable stents in our institution between 2012 and 2015. The following data were collected: demographics, indication for stenting, bronchoscopic findings, insertion technique complications, clinical outcome, stent related complications, re-stenting, and time of follow-up. RESULTS: Thirteen custom-made polydioxanone stents were placed in four infants (mean age, 4 months) with severe tracheobronchial obstruction: tracheomalacia (two patients), bronchomalacia (1), and diffuse tracheal stenosis (1). All the stents were bronchoscopically inserted uneventfully. Immediate and maintained clinical improvement was observed in every case. No major stent related complications have occurred and only mild or moderate granulation tissue was observed during surveillance bronchoscopy. Two patients required repeated stenting as expected. All the patients are alive and in a good respiratory condition with a follow-up ranging from 5 to 40 months. CONCLUSIONS: Biodegradable airway stents seem to be safe, effective, and cause fewer complications than other types of stents. They can be an alternative to the classic metallic or plastic stents for severe tracheal stenosis or malacia in small children. More experience is needed in order to establish the definite clinical criteria for their use in pediatric patients. Pediatr Pulmonol. 2016;51:607-612. © 2015 Wiley Periodicals, Inc.

Treatment strategies in the management of severe complications following slide tracheoplasty in children.

OBJECTIVES: This study focuses on the different surgical and endoscopical treatment alternatives when dealing with severe complications after slide tracheoplasty (STP). METHODS: Retrospective study of patients with symptomatic congenital tracheal stenosis (CTS) admitted to a single institution, between January 1997 and January 2013, surgically treated by means of STP. The following variables were evaluated: demographics, preoperative tracheal stenosis characteristics, associated anomalies and outcome measures. RESULTS: Cohort included 14 patients (8 males and 6 females) with a mean age of 8.7 months when treated (range, 1-43 m). Eleven patients (78%) showed a long segment CTS (>30% of total tracheal length) and 9 (64%) had associated cardiac or great vessel anomalies (left pulmonary artery sling). Three patients (21%) showed severe postoperative complications that required significant airway reintervention: tracheal resection of a restenotic segment, laser division with balloon dilatation of a residual stenosis and placement of a biodegradable endotracheal stent in an extensive tracheal narrowing. All patients are in good clinical condition with a mean follow-up of 6.3 years (range, 2 months to 16 years). CONCLUSIONS: STP has become the procedure of choice when dealing with CTS. Although it shows clear advantages compared with other surgical techniques, severe and difficult to manage complications may occur. Surgeons involved in their treatment should be familiar with diverse surgical and endoscopical procedures. Biodegradable airway stenting is a new and promising technique when long and severe post-surgical tracheal stenosis is present.

Screening for symptoms of obstructive sleep apnea in children with severe craniofacial anomalies: assessment in a multidisciplinary unit.

OBJECTIVE: To assess the incidence of airway obstruction symptoms and the presence of obstructive sleep apnea in children with severe craniofacial anomalies by a proactive screening program using a standard questionnaire and cardiorespiratory polygraphy. PATIENTS AND METHODS: Children with severe craniofacial anomalies referred to our paediatric airway unit from February 2001 to June 2011 were eligible to be included in this retrospective, single centre study. Symptoms of airway obstruction were proactively investigated using the shorter version of the Pediatric Sleep Questionnaire (PSQ). Obstructive sleep apnea was assessed by means of cardiorespiratory polygraphy. Demographic data and reason for referral were also recorded. Primary outcomes were the prevalence of symptoms of airway obstruction and OSA. RESULTS: 44 children (24 girls) with severe craniofacial anomalies (15 Crouzon, 13 Apert, 9 Goldenhar, 5 Treacher-Collins, 2 Pfeiffer) were included, at a mean age of 5 years (range 8 months to 14 years). Reason for referral was routine follow up in 30 patients and overt OSA symptoms and signs in the remaining 14. PSQ results showed symptoms of airway obstruction in 82% of patients, being snoring the most frequent symptom (64.1%) followed by apneas (33.3%). Polygraphic studies showed inconclusive results in 8 children (18.2%), normal apnea-hypopnea index (AHI) in 16 (36.4%), mild obstructive sleep apnea in 9 (20.4%), moderate in 4 (9.1%) and severe obstructive sleep apnea in 7 (15.9%). CONCLUSIONS: Children with craniofacial anomalies have a high prevalence of symptoms of airway obstruction and obstructive sleep apnea that support a proactive screening strategy in this highly selected population.

The role of bronchoscopy in the management of patients with severe craniofacial syndromes.

PURPOSE: The purpose of this study is to assess the incidence of airway anomalies in children with severe craniofacial syndromes and to establish the role of bronchoscopy in the care of these patients. METHODS: Consecutive children with craniofacial syndromes, including both bony deformities of the skull and face, in which a bronchoscopy was performed between 1995 and 2010 were retrospectively reviewed. RESULTS: Thirty-six patients (22 boys, 14 girls; mean age, 39 months) were studied. Craniofacial synostosis was present in 21 patients (Crouzen syndrome, 11; Apert syndrome, 7, Pfeiffer syndrome, 3) and craniofacial dysostosis in 15 (Goldenhart syndrome, 8; Treacher Collins syndrome, 7). In 30 patients (83.3%), bronchoscopy was performed because of respiratory symptoms (apneic episodes, 22; respiratory distress, 13; stridor, 6; cyanosis, 1) and, in the remaining 6 (asymptomatic children), during guided tracheal intubation before a surgical procedure. Airway anomalies were found in 69.4% of patients (70% in symptomatic patients). Management consisted of tracheotomy in 13 patients, adenoidectomy/tonsillectomy in 13, glossopexy in 5, antireflux surgery in 3, and supraglottoplasty in 2. CONCLUSIONS: Airway anomalies occurred in 70% of children with severe craniofacial syndromes and respiratory symptoms. Bronchoscopy should be performed routinely in this selected group of patients, and the entire airway must be examined. Treatment should be tailored to each individual patient.

Slide tracheoplasty in an infant with congenital tracheal stenosis and oesophageal atresia with tracheoesophageal fistula.

Slide tracheoplasty has become the treatment of choice when dealing with congenital tracheal stenosis (CTS). Versatility and effectiveness are the specific advantages of this technique when compared with other surgical procedures for tracheal reconstruction. We report a new use of slide tracheoplasty in a patient with a short CTS and a tracheal pouch after oesophageal atresia with tracheoesophageal fistula repair.

Congenital subglottic web: a rare cause of neonatal stridor.

Laryngeal web is a rare malformation caused by an anomalous embryologic development of the primitive larynx. Most of the reported cases are of the glottic type; the subglottic web is extremely rare. Laryngotracheobronchoscopy plays an essential role in the diagnostic workup of this lesion, and endolaryngeal resection is the preferred treatment whenever a structural cartilaginous subglottic stenosis is not present. The authors present the case of a neonate with a subglottic web diagnosed soon after birth. Management of this rare entity is discussed.

The role of airway stenting in pediatric tracheobronchial obstruction.

OBJECTIVE: Tracheobronchial obstruction is infrequent in the pediatric age group but it is associated with significant morbidity and mortality. The purpose of this study is to review the results of a single institution experience with endoscopic stent placement in children with benign tracheobronchial obstruction, and with special concern on safety and clinical effectiveness. MATERIALS AND METHODS: Twenty-one patients with severe airway stenosing disease in which stent placement was performed between 1993 and 2006. Inclusion criteria according to the clinical status were: failure to wean from ventilation, episode of apnea, frequent respiratory infections (>3 pneumonia/year), and severe respiratory distress. Additional criteria for stent placement were: failure of surgical treatment, bronchomalacia, and tracheomalacia refractory to previous tracheostomy. Selection of the type of stent depended on the site of the lesion, the patient's age, and the stent availability when time of presentation. The following variables were retrospectively evaluated: age, type of obstruction, associated malformations, stent properties, technical and clinical success, complications and related reinterventions, outcome and follow-up period. RESULTS: Thirty-three stents were placed in the trachea (n=18) and/or bronchi (n=15) of 21 patients with a median age of 6 months (range, 9 days-19 years). Etiology of the airway obstruction included severe tracheomalacia and/or bronchomalacia in 19 cases (90%), and postoperative tracheal stenosis in two. Twelve children had a total of 20 balloon-expandable metallic stents placed, and 10 had 13 silicone-type stents (one patient had both). In nine patients (42%) more than one device was placed. Stent positioning was technically successful in all but one patient. Clinical improvement was observed in 18 patients (85%) but complications occurred in five of them (27%). Eight patients died during follow-up but only in one case it was related to airway stenting. Thirteen patients (62%) are alive and in good condition with a mean follow-up of 39 months (1-13.8 years). CONCLUSIONS: Although the results were based on a small series, placement of stents in the pediatric airway to treat tracheobronchial obstruction seems to be safe and effective. Stenting is a satisfactory therapeutic option when other procedures have failed or are not indicated.