Management of pediatric tracheal stenosis and tracheomalacia

The clinical safety and efficacy of flexible bronchoscopy in a neonatal intensive care unit

Flexible bronchoscopy (FB), developed in the 1960s, is widely used in the clinical practice of pediatrics and has demonstrated fundamental value in clinical diagnoses and treatment. However, as an invasive procedure, the use of FB is limited due to concerns regarding the tolerance of the procedure and the possible complications in neonatal units. Thus, the present study aimed to investigate the clinical safety and efficacy of flexible bronchoscopy (FB) in a neonatal intensive care unit (NICU). Neonates (n=54) who received FB in the NICU of Shanghai Children's Hospital between January 2012 and December 2016 were enrolled as the experimental group and another 54 neonates who required nebulization and tracheal secretion suction treatments were the control group. Indicators including blood gas, complete blood count, C-reactive protein (CRP), X-ray, patient breathing rate, temperature and blood pressure were monitored prior to and following the procedure. No significant differences in sex, gestational age, birth weight or postnatal age were observed between the experimental group and the control group (P>0.05). Among the 54 FB patients, several cases with side effect were identified, including 18 (33.3%) with respiratory tract stenosis, nine (16.7%) with malacia and stenosis and six (11.1%) with esophagotracheal fistula. Among the 54 members of the control group, 44 neonates (81.4%) were discharged with improved condition, five (9.3%) succumbed and five patients (9.3%) abandoned the treatment and left the hospital. Bronchoalveolar lavage demonstrated consistent results with respiratory secretion culture or tracheal tube culture. In comparison between the experimental and the control groups, no significant difference in pH, partial pressure of carbon dioxide (PCO₂), partial pressure of oxygen (PO₂) and HCO₃ ^- was observed, while there were no statistical differences in the values of pH, PCO₂ and HCO₃ ^- (P>0.05). However, PO₂ was significantly increased, and CRP was significantly reduced, following FB procedure compared with prior to FB (P<0.05). No pneumothorax, shock, other severe complications, fever or diffused pneumonia were observed during or after FB. The data from the present study demonstrated that FB is a safe and effective strategy for the diagnosis and differentiation of neonatal respiratory diseases in NICU.

Tracheobronchial stenting for airway malacia

Tracheobronchomalacia is a rare but clinically troublesome condition in paediatrics. The softening of the major airways - which can include some or all of the tracheobronchial tree can lead to symptoms ranging from the minor (harsh barking cough, recurrent chest infections) to severe respiratory difficulties including prolonged ventilator support and 'near death attacks'. The causes are broadly divided into intrinsic softening of the airway wall which is considered a primary defect (e.g. syndromes; post tracheo-oesophageal fistula repair; extreme prematurity) or secondary malacia due to external compression from vascular structures or cardiac components. These secondary changes can persist even when the external compression is relieved, for example, following the repair of a pulmonary artery sling or double aortic arch. For children with severe clinical symptoms attributed to malacia, consideration is given to possible surgical remedies such as an aortopexy for short limited areas of malacia, or long term positive pressure support with CPAP either by non invasive or tracheostomy interface. More recently the role of stenting in children is receiving attention, especially with the development of newer techniques such as bioabsorbable stents which buy time for a natural history of improvement in the malacia to occur. This paper reviews the stents available and discusses the pros and cons of stenting in paediatric airway malacia.

Tracheal and bronchial stenoses and other obstructive conditions

Although tracheal stenosis and bronchial stenosis are relatively rare in the pediatric population, they are both associated with significant morbidity and mortality. While most cases of congenital tracheal stenosis in children present as complete tracheal rings (CTRs), other congenital tracheal obstructions are also encountered in clinical practice. In addition, acquired obstructive tracheal conditions stemming from endotracheal trauma or previous surgical interventions may occur. Many affected children also have associated cardiovascular malformations, further complicating their management. Optimal management of children with tracheal or bronchial stenoses requires comprehensive diagnostic evaluation and optimization prior to surgery. Slide tracheoplasty has been the operative intervention of choice in the treatment of the majority of these children.

Emergency management for congenital tracheal stenosis with endoluminal stenting in pediatric intensive care units

OBJECTIVE

The objective of this study was to share our experience in the management of congenital tracheal stenosis (CTS) using self-expanding intraluminal stents in infants.

METHODS

From January 2010 to August 2012, 31 infants with CTS treated using stents by bronchoscope in pediatric intensive care units (PICUs) were recruited for this study.

RESULTS

Among the 31 patients, 17 were male and 14 were female with their ages ranging from 55 days to 22 months. CTS was associated with congenital heart disease (CHD) in 22 patients. There were no immediate stent-related airway complications. A significant and immediate improvement of respiratory obstruction following stent placement in all 31 patients led to successful weaning from the breathing machine and extubation. Granulation tissue formation as a complication was observed in three (9.7%) patients, but all were successfully managed using cryotherapy. During follow up (up to 24 months), stents in 29 infants remained functional. In seven cases, stents were retrieved under bronchoscope (the same day to 10 months), and three cases required stent replacement (each of the three cases had the stent replaced three times). Nine infants died after stenting due to other causes and two infants abandoned treatment.

CONCLUSION

Airway stenting may provide an important therapeutic option in infants with CTS.

Management of tracheomalacia in an infant with Tetralogy of Fallot

Most infants with tracheomalacia do not need specific therapy as it usually resolves spontaneously by the age of 1–2 years. Severe forms of tracheomalacia characterized by recurrent respiratory infections require active treatment which includes chest physiotherapy, long term intubation or tracheostomy. Aortopexy seems to be the treatment of choice for secondary and even primary forms of severe tracheomalacia. Itentails tracking and suturing the anterior wall of the aorta to the posterior surface of the sternum. Consequently, the anterior wall of the trachea is also pulled forward preventing its collapse. A 3-month-old girl baby who was on ventilatory support for 2 months due to severe tracheomalacia associated with a cyanotic congenital heart disease underwent intracardiac repair and aortopexy along with Lecompte's procedure as all the conservative measures to wean off the ventilator failed. The baby was extubated on the third post-operative day and the post-operative period was uneventful.

Management of tracheobronchial obstruction in infants using metallic stents: long-term outcome

INTRODUCTION

Tracheobronchial obstruction, although uncommon in the pediatric age group, remains a challenging problem. We review the long-term outcome of endoscopic metallic stenting in infants with tracheobronchial obstruction.

MATERIALS AND METHODS

Medical records of all pediatric surgical patients who underwent tracheobronchial metallic stenting in our center were reviewed retrospectively from 1996 to 2014. Patients' demographic data, including etiology, associated anomalies and nature of obstruction were reviewed. Outcome measures include complications such as re-stenosis, granulation tissue, stent migration, fractured stent, maximal tracheal diameter achieved, weaning of ventilator and growth at interval follow-up.

RESULTS

Twelve balloon-expandable metallic stents were placed in the trachea (n = 10) and/or bronchi (n = 2) of 5 patients with a median age of 13 months (range 5-30 months). Etiology of the airway obstruction included congenital tracheal stenosis (n = 4), giant cervical and superior mediastinal lymphatic malformation with tracheobronchomalacia (n = 1). Seven complications were reported (3 patients developed granulation tissue, 2 patients had re-stenosis, 1 stent migrated, 1 stent fractured). All patients survived and were in good condition with a median follow-up of 16 years (range 11-18 years). Three patients weaned off ventilator and oxygen.

CONCLUSIONS

Endoscopic stenting with metallic stent has satisfactory long-term outcome in treating infants with tracheobronchial obstruction.

Thermoforming of tracheal cartilage: viability, shape change, and mechanical behavior

BACKGROUND AND OBJECTIVES

Trauma, emergent tracheostomy, and prolonged intubation are common causes of severe deformation and narrowing of the trachea. Laser technology may be used to reshape tracheal cartilage using minimally invasive methods. The objectives of this study were to determine: (1) the dependence of tracheal cartilage shape change on temperature and laser dosimetry using heated saline bath immersion and laser irradiation, respectively, (2) the effect of temperature on the mechanical behavior of cartilage, and (3) tissue viability as a function of laser dosimetry.

MATERIALS AND METHODS

Ex vivo rabbit trachea cartilage specimens were bent and secured around a cylinder (6 mm), and then immersed in a saline bath (45 and 72 degrees C) for 5-100 seconds. In separate experiments, tracheal specimens were irradiated with a diode laser (lambda = 1.45 microm, 220-400 J/cm(2)). Mechanical analysis was then used to determine the elastic modulus in tension after irradiation. Fluorescent viability assays combined with laser scanning confocal microscopy (LSCM) were employed to image and identify thermal injury regions.

RESULTS

Shape change transition zones, between 62 and 66 degrees C in the saline heating bath and above power densities of 350 J/cm(2) (peak temperatures 65+/-10 degrees C) for laser irradiation were identified. Above these zones, the elastic moduli were higher (8.2+/-4 MPa) than at lower temperatures (4.5+/-3 MPa). LSCM identified significant loss of viable chondrocytes within the laser-irradiation zones.

CONCLUSION

Our results indicate a change in mechanical properties occurs with laser irradiation and further demonstrates that significant thermal damage is concurrent with clinically relevant shape change in the elastic cartilage tissues of the rabbit trachea using the present laser and dosimetry parameters.

The role of endoluminal self-expanding stents in the management of pediatric tracheal stenosis

OBJECTIVE

Review of our experience in the management of pediatric tracheal stenosis using endoscopic techniques and self-expanding intraluminal stents.

METHODS

Thirteen children (aged 1 week to 14 years) with various causes of tracheal stenosis were treated. A total of 15 stents were used, 13 self-expanding nitinol stents and 3 silicone self-expanding stents. Follow-up ranged from 6 month to 8 years.

RESULTS

There were no stent related mortalities. Serious complications occurred in 4 patients [30.7%] but all were managed successfully. The most frequent problem was granulation tissue formation. Patient follow-up ranged from 6 months to 8 years. In the short-term (18-24 months) 12 stents remained patent and functional. On the longer term (5 years) 3 stents required removal, one required replacement and another resulted in stenosis.

CONCLUSION

Endoluminal stenting can have an increasing role in the management of selected cases pediatric tracheal stenosis with acceptable morbidity and stable long-term results.

Acquired Nonneoplastic Neonatal and Pediatric Diseases

The lung biopsy is an established procedure to procure a pathologic diagnosis in a child with a suspected pneumonic process of undetermined etiology. Improvements in pediatric anesthesia and surgery have reduced the operative complications to a minimum. A biopsy can usually be taken through a small intercostal incision when localization is not especially important in a patient with diffuse changes (see Chapter 1). The alternative method for tissue sampling is the endoscopic transbronchial biopsy. There is less risk to the patient, but the specimen is smaller and crush artifacts from the instrument are more common.