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

Bronchial Remodeling Following Airway Stenting in Pediatric Patients With Tracheobronchial and Congenital Heart Disease

Background

Treatment of tracheobronchial disease in medically complex infants with congenital heart disease (CHD) is often challenging. When conservative management or surgery fails or is contraindicated, airway stenting can allow for advancement of care or weaning of respiratory support.

Methods

We identified 8 cases of airway stenting with balloon-expandable coronary bare-metal stents performed at our institution between February 2019 and September 2022 to relieve conservative treatment-refractory tracheobronchial disease in pediatric patients with CHD. All patients underwent rigid microlaryngoscopy, bronchoscopy, and flexible bronchoscopy as well as computed tomography angiography.

Results

Eight patients underwent technically uncomplicated placement of balloon-expandable coronary bare-metal stents in the trachea or bronchus. Immediate improvement in respiratory parameters was noted following stent placement. Six patients were able to wean mechanical ventilation following stent placement, with a median of 2.5 days of mechanical ventilation following the procedure (range, 0-219). All stents were subsequently endoscopically removed at a median of 6.8 months (range, 0.4-16.3 months). In 6 patients, bronchoscopy after stent removal demonstrated a rounder configuration of the airway consistent with bronchial remodeling.

Conclusions

In pediatric patients with tracheobronchial and CHD, airway stenting with balloon-expandable bare-metal coronary stents relieved respiratory symptoms with minimal complications and resulted in bronchial remodeling after stent removal.

Silicon stent placement via rigid bronchoscopy for the treatment of central airway obstruction in infants: Case series

INTRODUCTION

Rigid bronchoscopy has been proven to be an excellent tool for the diagnosis and management of several causes of central airway obstruction (CAO). The invasive treatment of silicone bronchobrachial stenting has been performed in children and adults with CAO, and satisfying results were obtained in previous studies. However, there are few reports on infants with central airway obstruction treated with stenting via rigid bronchoscopy. This technique remains a challenge to pediatric thoracic surgeons, pediatric interventional pulmonologists, and otolaryngologists who struggle to treat airway obstruction disease.

PATIENT CONCERNS

Four patients were presented to our hospital with complaints of dyspnea for a period of time after their birth.

DIAGNOSIS

Three patients were diagnosed as tracheobronchomalacia, and tracheoesophageal fistula.

INTERVENTIONS

Four patients were treated with silicone stenting through rigid bronchoscopy.

OUTCOMES

Silicon stent was adequate for improving the obstruction of the tracheal tract. All the patients were followed-up longer than 6 months. Three patients could breathe normally; the stent migrated in only 1 patient.

CONCLUSION

Invasive silicone tracheobronchial stenting via rigid bronchoscopy is a viable option for infants with CAO. Choosing an appropriate size is a critical factor for success of stenting according to our experience.

A new airway spiral stent designed to maintain airway architecture with an atraumatic removal after full epithelization-Research of feasibility and viability in canine patients with tracheomalacia

OBJECTIVE

Surgical management of tracheomalacia is a challenge, with current treatments still presenting numerous complications. In the field of veterinary medicine, this same pathology is present in a significant number of dogs. For this reason, we present an experimental clinical trial performed on canines with tracheobronchomalacia, using a new atraumatic removable tracheal spiral stent (SS). Both implantation procedure and clinical improvement have been analyzed in this study.

METHODS

In this study, four small dogs, a mean weight of 4.89 kg and body condition scores IV-V, were included. SS was implanted by two different surgical approaches. Image and clinical follow-up have been performed during 90 days. Symptoms were evaluated from 1 to 10 every week.

RESULTS

This study achieved 100% technical and clinical success. Median tracheal diameters were as follows: cervical 10.85 (3.3), inlet 7.75 (2.1), and carina 7.75 (1.9) mm, and length was 77.5 (26) mm. A 12 × 10 × 100-mm SS was implanted in all cases. Goose honk cough punctuation improved from 8 to 1; also, there were important changes in exercise intolerance, a mean weight loss of 8.76%. The values of modified Karnofsky scale varied from 50 (20) before surgery to 90 (10) after 30 days of surgery. Neither granuloma tissue nor fractures of the prosthesis was observed.

CONCLUSION

The results in dogs are promising, and a new therapeutic alternative seems to be available for veterinarian field. The similarity of this disease between dogs and newborns suggests that this SS design can also be useful for human trials.

Follow-Up Investigation of 41 Children After Metallic Airway Stent Implantation: An 8-Year Experience

Objective: To present 8-year follow-up outcomes, treatment of complications, and prognosis in children with congenital tracheal stenosis after metallic airway stent implantation. Methods: Retrospective analysis was performed on the clinical records of children who had airway stents placed between May 20, 2011 and May 31, 2016, and on their follow-up records collected on November 31, 2019. Results: During the 8 years follow-up, 41 children underwent airway stenting under flexible bronchoscopy and participated in the follow-up investigation. There were 26 cases with left main bronchus (LMB) stenosis (63.4%), 16 cases with congenital tracheal stenosis (CTS, 39.0%), 12 cases with right main bronchus (RMB) stenosis (29.3%), and 1 case of subglottic stenosis (2.4%). A total of 76 stents were implanted, and 21 patients died after implantation. There were 34 children (82.9%) with congenital heart disease (CHD), while other diseases accounted for <5%. Among children with CHD and those with other conditions, the number of death cases was 19 and 2, respectively; no significant differences were observed between the two groups (P>0.05). The most frequent complications were increased airway secretion (75.8%), stent deformation (66.7%), and granulation tissue hyperplasia (60.6%). The airway stenosis (45.5%) and stent migration (12.1%) occurred at a moderate rate. The less common complications were airway softening (6.1%), and stent breakage (6.1%). Conclusions: The placement and removal of the metallic stent are convenient and quick procedures that can relieve the symptoms of dyspnea caused by airway stenosis in the case of an emergency. After stent implantation, the primary disease should be actively treated, and the stent should be removed as soon as possible after the cause of airway stenosis is successfully removed. Larger stents are more likely to cause complications; thus, a good follow-up system should be established to timely address all the complications.

Long-term management and outcomes of tracheobronchial stent by flexible bronchoscopy in infants <5 kg: A 13-year single-center experience

BACKGROUND

Tracheobronchial (TB) lumen narrowing may require prolonged positive-pressure ventilation, endotracheal tube intubation or even surgical interventions. Therapeutic flexible bronchoscopy (TFB) of balloon-expandable metallic stent (BEMS) placement and subsequent forceps, laser and balloon dilatation management might be less invasive and helpful. This study aimed to analyse the placement, follow-up management with TFB and long-term outcomes in small infants with BEMS.

METHODS

This retrospective study reviewed the medical records and associated TFB videos of infants with a maximum body weight (BW) of 5.0 kg who had TB BEMS placement from January 2005 to December 2017 at our institution. All TFB procedures were supported with a novel noninvasive ventilation, nasopharyngeal oxygen with intermittent nose closure and abdominal compression.

RESULTS

Forty-one BEMSs were placed in 24 infants. The mean BW and mean age were 4.0 ± 0.7 kg and 4.9 ± 2.4 months, respectively. There were 20, 8 and 13 stents located in trachea, carina and main-stem bronchi, respectively. Seven infants with 13 stents died without obvious stent-related mortality. Seven stents in five infants were successfully retrieved by rigid endoscopy (RE). At placement, the diameters of 28 tracheal and 21 bronchial stents were 7.5 ± 1.1 (4-10) and 5.4 ± 0.9 (4-8) mm, respectively. These implanted BEMSs could be gradually and significantly (p < 0.01) expanded. At the end of the follow-up period, all the remaining 21 stents in 12 infants were functional. The diameters of the 14 remaining tracheal and 13 remaining bronchial stents were 9.6 ± 2.0 (8-14) and 7.2 ± 1.4 (4-10) mm, respectively.

CONCLUSION

BEMSs are practical and effective in selected small infants with benign TB narrowing and can be safely implanted and managed with TFB, and finally retrieved by RE.

Outcome of long-term complications after permanent metallic left bronchial stenting in children

OBJECTIVES

We describe the way we treated 7 children with critical long-term complications after metallic balloon-expandable stenting in the left mainstem bronchus.

METHODS

Endoscopic follow-up included a first bronchoscopy 3 weeks after stenting, then monthly for 3 months, every 4-6 months up to 1 year and at scheduled times to calibrate stent diameter up to final calibration. When major complications occurred, patients underwent chest computed tomographic angiography.

RESULTS

In 1 of the 7 children (median age 2.8 years), metallic left bronchial stenting served as a bridge to surgery. After a median 4-year follow-up, all 7 children experienced recurrent stent ovalizations with stent breakage in 3 and erosion in 1. In 4 children, computed tomographic angiography showed abundant peribronchial fibrous tissue, in 2 left mediastinal rotation and in 1 displacement along the left bronchus after pulmonary re-expansion as the cause of stent-related complication. Of the 7 children, 6 underwent surgery (5 posterior aortopexy and 1 section of the ligamentum arteriosus) and 3 required nitinol stents placement within the metallic ones. One patient completed the follow-up, and 1 patient was lost to follow-up. All 5 remaining children still have permanent bronchial stents in place, patent and re-epithelialized after a median 10.5-year follow-up. There were no deaths.

CONCLUSIONS

Satisfactory anatomical relationships when children have stents placed in the left mainstem bronchus alone do not guarantee the final success. Several mechanisms intervene to cause critical stent-related complications in children during growth. Permanent metallic stents should be used carefully, and only in selected patients.

Beyond dilation: current concepts in endoscopic airway stenting and reconstruction

PURPOSE OF REVIEW

To discuss current modalities of endoscopic airway management beyond balloon dilation therapy.

RECENT FINDINGS

Advances continue to be made through technology and bioengineering with exciting potential in the pediatric airway. Smaller robots and instrumentation allow increased endoscopic surgical success. Biodegradable stents and bioengineered grafts are on the horizon for use in airway surgery. Dysphonia following airway reconstruction is of increasing recognition with new endoscopic treatments being performed. Supraglottoplasty is further recognized as a treatment for obstructive sleep apnea for laryngomalacia diagnosed on sleep endoscopy. Interarytenoid injection may be beneficial in the normal larynx for aspiration and dysphagia as well as diagnosing and treating type I laryngeal clefts.

SUMMARY

Endoscopic airway surgery continues to be a popular and effective method of treating the pediatric airway. Technological advances such as in robotics may have an increasing role in the future of endoscopic airway surgery in children. Bioengineered airway adjuncts including biodegradable airway stents look to be promising in the future treatment of airway stenosis.

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.

Paclitaxel Drug-eluting Tracheal Stent Could Reduce Granulation Tissue Formation in a Canine Model

Background:

Currently available silicone and metallic stents for tracheal stenosis are associated with many problems. Granulation proliferation is one of the main complications. The present study aimed to evaluate the efficacy of paclitaxel drug-eluting tracheal stent in reducing granulation tissue formation in a canine model, as well as the pharmacokinetic features and safety profiles of the coated drug.

Methods:

Eight beagles were randomly divided into a control group (bare-metal stent group, n = 4) and an experimental group (paclitaxel-eluting stent group, n = 4). The observation period was 5 months. One beagle in both groups was sacrificed at the end of the 1^st and 3^rd months, respectively. The last two beagles in both groups were sacrificed at the end of 5^th month. The proliferation of granulation tissue and changes in tracheal mucosa were compared between the two groups. Blood routine and liver and kidney function were monitored to evaluate the safety of the paclitaxel-eluting stent. The elution method and high-performance liquid chromatography were used to characterize the rate of in vivo release of paclitaxel from the stent.

Results:

Compared with the control group, the proliferation of granulation tissue in the experimental group was significantly reduced. The drug release of paclitaxel-eluting stent was the fastest in the 1^st month after implantation (up to 70.9%). Then, the release slowed down gradually. By the 5^th month, the release reached up to 98.5%. During the observation period, a high concentration of the drug in the trachea (in the stented and adjacent unstented areas) and lung tissue was not noted, and the blood test showed no side effect.

Conclusions:

The paclitaxel-eluting stent could safely reduce the granulation tissue formation after stent implantation in vivo, suggesting that the paclitaxel-eluting tracheal stent might be considered for potential use in humans in the future.

Combined use of Neurally Adjusted Ventilatory Assist (NAVA) and Vertical Expandable Prostethic Titanium Rib (VEPTR) in a patient with Spondylocostal dysostosis and associated bronchomalacia

Jarcho-Levin syndrome is a rare disorder characterised by defects in vertebral and costal segmentation of varying severity. Respiratory complications are the main cause of death or severe comorbidity due to a restrictive rib cage. A 3 months old infant with Spondylocostal dysostosis and associated bronchomalacia experiencing severe asynchrony during the weaning process is reported. The Neurally Adjusted Ventilatory Assist (NAVA) mode was used to improve adaptation to mechanical ventilation after Vertical Expandable Prosthetic Titanium Ribs (VEPTRs) were implanted. The synchrony achieved with the NAVA mode allowed a decrease of the sedoanalgesia he received. A follow-up CT scan showed a reduction in the volume of the posterobasal atelectasis. The evolution of this patient suggests that the combined use of VEPTR for thoracic expansion and ventilation using NAVA can favour the global improvement. This mode could be an option to consider in selected patients with difficult weaning from mechanical ventilation in paediatric intensive care units.

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.

Stent implantation into the tracheo-bronchial system in rabbits: histopathologic sequelae in bare metal vs. drug-eluting stents

Background

Stent implantation into the tracheo-bronchial system may be life-saving in selected pediatric patients with otherwise intractable stenosis of the upper airways. Following implantation, significant tissue proliferation may occur, requiring re-interventions. We sought to evaluate the effect of immunosuppressive coating of the stents on the extent of tissue proliferation in an animal model.

Methods

Bare metal and sirolimus-coated stents (Bx Sonic and Cypher Select, Johnson & Johnson, Cordis) were implanted into non-stenotic lower airways of New Zealand white rabbits (weight 3.1 to 4.8 kg). Three stents with sirolimus coating and six bare metal stents could be analyzed by means of histology and immunohistochemistry 12 months after implantation.

Results

On a macroscopic evaluation, all stents were partially covered with a considerable amount of whitish tissue. Histologically, these proliferations contained fiber-rich connective tissue and some fibromuscular cells without significant differences between both stent types. The superficial tissue layer was formed by typical respiratory epithelium and polygonal cells. Abundant lymphocyte infiltrations and moderate granulocyte infiltrations were found in both groups correspondingly, whereas foreign-body reaction was more pronounced around sirolimus-eluting stents.

Conclusions

After stent implantation in the tracheo-bronchial system of rabbits, we found tissue reactions comparable to those seen after stent implantation into the vascular system. There was no difference between coated and uncoated stents with regard to quality and quantity of tissue proliferation. We found, however, a significantly different inflammatory reaction with a more pronounced foreign-body reaction in sirolimus-coated stents. In our small series, drug-eluting stents did not exhibit any benefit over bare metal stents in an experimental setting.