Immediate, short-, and long-term changes in tracheal stent diameter, length, and positioning after placement in dogs with tracheal collapse syndrome

BACKGROUND

Intraluminal tracheal stenting is a minimally invasive procedure shown to have variable degrees of success in managing clinical signs associated with tracheal collapse syndrome (CTCS) in dogs.

OBJECTIVES

Identify immediate post-stent changes in tracheal diameter, determine the extent of stent migration, and stent shortening after stent placement in the immediate-, short-, and long-term periods, and evaluate inter-observer reliability of radiographic measurements.

ANIMALS

Fifty client-owned dogs.

METHODS

Retrospective study in which medical records were reviewed in dogs with CTCS treated with an intraluminal tracheal stent. Data collected included signalment, location, and type of collapse, stent diameter and length, and post-stent placement radiographic follow-up times. Radiographs were used to obtain pre-stent tracheal measurements and post-stent placement measurements.

RESULTS

Immediate mean percentage change was 5.14%, 5.49%, and 21.64% for cervical, thoracic inlet, and intra-thoracic tracheal diameters, respectively. Ultimate mean follow-up time was 446 days, with mean percentage change of 2.55%, 15.09%, and 8.65% for cervical, thoracic inlet, and intra-thoracic tracheal diameters, respectively. Initial mean stent length was 26.72% higher than nominal length and ultimate long-term tracheal mean stent shortening was only 9.90%. No significant stent migration was identified in the immediate, short-, or long-term periods. Good inter-observer agreement of radiographic measurements was found among observers of variable experience level.

CONCLUSIONS AND CLINICAL IMPORTANCE

Use of an intraluminal tracheal stent for CTCS is associated with minimal stent shortening with no clinically relevant stent migration after fluoroscopic placement. Precise stent sizing and placement techniques likely play important roles in avoiding these reported complications.

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.

Engineered Tissue-Stent Biocomposites as Tracheal Replacements

Here we report the creation of a novel tracheal construct in the form of an engineered, acellular tissue-stent biocomposite trachea (TSBT). Allogeneic or xenogeneic smooth muscle cells are cultured on polyglycolic acid polymer-metal stent scaffold leading to the formation of a tissue comprising cells, their deposited collagenous matrix, and the stent material. Thorough decellularization then produces a final acellular tubular construct. Engineered TSBTs were tested as end-to-end tracheal replacements in 11 rats and 3 nonhuman primates. Over a period of 8 weeks, no instances of airway perforation, infection, stent migration, or erosion were observed. Histological analyses reveal that the patent implants remodel adaptively with native host cells, including formation of connective tissue in the tracheal wall and formation of a confluent, columnar epithelium in the graft lumen, although some instances of airway stenosis were observed. Overall, TSBTs resisted collapse and compression that often limit the function of other decellularized tracheal replacements, and additionally do not require any cells from the intended recipient. Such engineered TSBTs represent a model for future efforts in tracheal regeneration.

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.