Complications of Metallic Stents in the Pediatric Airway

Degrees of Inflammation in the Treatment of Subglottic Stenosis in a Rabbit Model: Histopathological Assessment of a Novel Bioabsorbable Ultra-high Ductility Magnesium Alloy Stent

OBJECTIVE

Utilizing a novel histopathological scoring system and subglottic stenosis (SGS) rabbit model, we aimed to compare degrees of inflammation and severity of narrowing in the subglottis between two minimally invasive therapeutic modalities: endoscopic balloon dilation (EBD) alone versus EBD with placement of a bioabsorbable ultra-high ductility magnesium (UHD-Mg) alloy stent.

METHODS

SGS was induced endoscopically via microsuspension laryngoscopy in 23 New Zealand white rabbits. The control group (n = 11) underwent EBD alone, the study arm (n = 12) underwent EBD with implantation of bioabsorbable UHD-Mg alloy stents. Rabbits were euthanized at 2-, 3-, and 6-weeks after SGS induction, coinciding with wound healing stages. Using Optical Coherence Tomography (OCT), cross-sectional areas of airways were compared to calculate the mean percentage of intraluminal area at sequential time points. A novel histopathological scoring system was used to analyze frozen sections of laryngotracheal complexes. The degree of inflammation was quantified by scoring changes in inflammatory cell infiltration, epithelial ulceration/metaplasia, subepithelial edema/fibrosis, and capillary number/dilation. Univariate analysis was utilized to analyze these markers.

RESULTS

We found rabbits implanted with the bioabsorbable UHD-Mg alloy stent had statistically significantly higher scores in categories of hyperplastic change (stents vs controls: 1.48 vs 0.46 p < 0.001), squamous metaplasia (22 vs 5 p < 0.001), and neutrophils/fibrin in lumen (31 vs 8, p < 0.001). Rabbits who received EBD alone had higher scores of subepithelial edema and fibrosis (2.70 vs 3.49, p < 0.0256). The stented rabbits demonstrated significantly increased mean percent stenosis by intraluminal mean area compared to controls at 2 weeks (88.56 vs 58.98, p = 0.032), however at all other time points there was no significant difference between intraluminal subglottic stenosis by mean percent stenosis area.

DISCUSSION

Rabbits with SGS treated with UHD-Mg alloy stents demonstrated histopathologic findings suggestive of lower levels of tracheal fibrosis. This could indicate a reduced tendency towards the development of stenosis when compared to EBD alone. There was not a difference in luminal size between stent and non-stented rabbits at the six-week end point. Histologically, however, overall the use of bioabsorbable UHD-Mg alloy stenting elicited a greater tissue response at the level of the superficial mucosa rather than fibrosis of the lamina propria seen in the stented rabbits. This suggests more favorable healing and less of a tendency towards fibrosis and stenosis even though there may not be a benefit from a luminal size standpoint during this early healing period. Compared to known complications of currently available non-bioabsorbable metal or silicone-based stents, this proof-of-concept investigation highlights the potential use of a novel biodegradable UHD-Mg stent as a therapeutic modality for pediatric SGS.

Single-center review on safety of biodegradable airway stenting in pediatric population

BACKGROUND

Tracheobronchomalacia (TBM) and airway stenosis are recognized etiologies of airway obstruction among children. Their management is often challenging, requiring multiple interventions and prolonged respiratory support with associated long-term morbidity. Metallic or silicone stents have been used with mixed success and high complication rates. More recently biodegradable Ella stents (BES) provided an attractive interventional option.

OBJECTIVES

We report our experience in the treatment of TBM and vascular airway compression using BES. We deliberately downsized them to minimize intraluminal granulation tissue formation.

MATERIALS AND METHODS

Retrospective study over an 8-year period between November 2012 and December 2020 of pediatric patients with severe airway obstruction requiring airway stenting for extubation failure, malacic death spells, recurrent chest infections, or lung collapse.

RESULTS

Thirty-three patients (5 tracheal and 28 bronchial diseases) required 55 BES during the study period. The smallest patient weighed 1.8 kg. Median age of patient at first stent implantation was 13.1 months (IQR 4.9-58.3). The majority of the bronchial stents were in the left main bronchus (93%), of which 57% for vascular compression. Repeat stents were used in 19 patients (57.7%), with a range of two to four times. We did not experience erosion, infection, or obstructive granuloma needing removal by forceps or lasering. Three stent grid occluded with secretions needing bronchoscopic lavage. Stent migration occurred in three patients.

CONCLUSIONS

BES holds promise as a treatment option with low rate of adverse effects for a specific subset of pediatric patients with airway malacia or vascular compression. Further studies are warranted.

Stereotactic technology for 3D bioprinting: from the perspective of robot mechanism

Three-dimensional (3D) bioprinting has been widely applied in the field of biomedical engineering because of its rapidly individualized fabrication and precisely geometric designability. The emerging demand for bioprinted tissues/organs with bio-inspired anisotropic property is stimulating new bioprinting strategies. Stereotactic bioprinting is regarded as a preferable strategy for this purpose, which can perform bioprinting at the target position from any desired orientation in 3D space. In this work, based on the motion characteristics analysis of the stacked bioprinting technologies, mechanism configurations and path planning methods for robotic stereotactic bioprinting were investigated and a prototype system based on the double parallelogram mechanism was introduced in detail. Moreover, the influence of the time dimension on stereotactic bioprinting was discussed. Finally, technical challenges and future trends of stereotactic bioprinting within the field of biomedical engineering were summarized.

Bronchial stenting in infants with severe bronchomalacia: Technique and outcomes

OBJECTIVES

To report the first use of a balloon expandable bare metal stent for treating infant bronchomalacia.

BACKGROUND

Infant bronchomalacia often requires prolonged mechanical ventilation and can be life-threatening. Effective treatment for severe infant bronchomalacia continues to be elusive. We present three cases of bronchial stenting for no-option or treatment refractory infant bronchomalacia.

METHODS

Three consecutive cases of stenting to relieve conservative treatment refractory severe infant bronchomalacia were performed between February 2019 and December 2020. Initial diagnosis was confirmed with Computed Tomography (CT) angiography. Patients underwent rigid micro laryngoscopy, bronchoscopy, and flexible bronchoscopy to evaluate the airway. Initial conservative management strategies were pursued. Patients failing initial conservative management strategies were considered for rescue bronchial stenting.

RESULTS

Our initial clinical experience with a coronary bare metal stent for these procedures has been favorable. The stent was easy to deploy with precision. We did not encounter stent embolization or migration. There was sufficient stent radial strength to relieve bronchomalacia without causing restenosis or erosion. There was no significant granulation tissue formation. In one patient, the stent was removed after 12 months of somatic growth; this was uneventful and bronchial patency was maintained. There were no complications in any of our patients regarding stent placement and reliability.

CONCLUSION

In cases of three infants with severe bronchomalacia, we found that bronchial stenting with the bare metal coronary stent was effective in relieving bronchial stenosis.

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.

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.

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.

Flexible endoscopy for pediatric tracheobronchial metallic stent placement, maintenance and long-term outcomes

OBJECTIVES

To assess the placement, surveillance management and long-term outcomes of the tracheobronchial (TB) balloon expandable metallic stent (BEMS) managed by therapeutic flexible endoscopy (TFE).

METHODS

This is a retrospective review and analysis of all computerized medical records and related flexible endoscopy videos of pediatric patients who received TB BEMS during 20 years period, from January 1997 to December 2016. TFE techniques with forceps debridement, balloon dilatation and laser ablation were used to implant stents, perform regular surveillance, maintain their functions, and expand the diameters of BEMS. Short-length (30cm-36cm) endoscopes of OD 3.2mm to 5.0mm coupled with the noninvasive ventilation, without ventilation bag, mask or airway tube, supported the whole procedures.

RESULTS

146 BEMS were implanted in 87 consecutive children, including 84 tracheal, 15 carinal and 47 bronchial stents. At the time of placement, the mean age was 35.6 ± 54.6 month-old (range 0.3-228) and the mean body weight was 13.9 ± 10.6 kg (range 2.2-60). Surveillance period was 9.4 ± 6.7 years (range, 0.3-18.0). Satisfactory clinical improvements were noted immediately in all but two patients. Seventy-two (82.8%) patients were still alive with stable respiratory status, except two patients necessitating TFE management every two months. Fifty-one stents, including 35 tracheal and 16 bronchial ones, were successfully retrieved mainly with rigid endoscopy. Implanted stents could be significantly (< .001) further expanded for growing TB lumens. The final stent diameters were positively correlated to the implanted duration. Altogether, 33 stents expired (15 patients), 51 were retrieved (40 patients), and 62 remained and functioning well (38 patients), with their mean duration of 7.4 ± 9.5, 34.9 ± 36.3 and 82.3 ± 62.5 months, respectively.

CONCLUSION

In pediatric patients, TFE with short-length scopes coupled with this NIV support has provided a safe, feasible and effective modality in placing and subsequently managing TB BEMS with acceptable long-term outcomes.

Short- versus Long-term Stenting in Children with Subglottic Stenosis Undergoing Laryngotracheal Reconstruction

Objectives Suprastomal stents are routinely used in laryngotracheal reconstruction (LTR) to stabilize grafts and provide framework to sites of repair. However, the duration of stenting varies according to patient history and physician preference. We examined outcomes of short- versus long-term stenting in children with subglottic stenosis (SGS) undergoing LTR. Study Design Case series with chart review. Setting Tertiary care pediatric hospital. Subjects and Methods Thirty-six children <18 years old who underwent double-stage LTR for SGS from January 2012 to January 2015 were included. Demographic data, stenosis grade, and decannulation rates were compared between children with short-term stenting (≤21 days; n = 14) and those with long-term stenting (>21 days; n = 22). Results No significant difference between groups was seen for sex, age, race, or previous repair. Children in the short-term group were stented for 10.9 ± 4.9 days, compared with 44.0 ± 10.6 for those long-term ( P < .0001). A similar number of children with short- versus long-term stents had grade 3/4 stenosis preoperatively (71.4% vs 77.2%). Although time to decannulation was not significantly different, 72.7% of children with long-term stents were decannulated, as opposed to 35.7% with short-term stents ( P = .03). After adjusting for grade at surgery and age, children with long-term stents had 4.3 greater odds (95% CI, 1.0-18.3) of decannulation than children with short-term stents. Conclusions Children with long-term stenting were more likely to be successfully decannulated. Although long-term stenting improved outcomes for children with SGS, additional research is needed to better define ideal candidates for short- versus long-term stenting.

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.

Tracheobronchial issues in congenital heart disease

In children with congenital heart disease, tracheobronchial compromise is uncommon but potentially life-threatening. Airway lesions in these patients may be congenital or acquired, and may be stenotic, compressive, or malacic in nature. We present an overview of the etiologies of tracheobronchial lesions typically seen in children with congenital heart disease and review management options for these lesions.

Broncho-vascular fistulas from self-expanding metallic stents: A retrospective case review

To highlight a potentially fatal complication of broncho-vascular fistula arising from the self expanding metallic stent (SEMS) placement. We retrospectively analyzed five patients with benign and malignant airway diseases, who developed tracheo/broncho-vascular fistulas following SEMS placement in our tertiary care setting. All patients received either Wallstent or Ultraflex^® stent (Boston Scientific, Natick, MA) between 1999 and 2007. All patients had received adjunct therapy such as balloon bronchoplasty, laser therapy or electrocautery. Most patients presented with massive hemoptysis. A total of 483 SEMS were placed during this period. SEMS placement can be complicated by Broncho-vascular fistula formation. True incidence and precise time interval between the insertion of stent and onset of this complication is unknown. Additional therapeutic modalities to maintain stent patency may enhance the risk of fistula formation. SEMS should only be used in a select sub-group of patients, after exhaustive evaluation of other treatment options. These cases provide evidence that broncho-vascular fistulas can develop at any time following SEMS placement, suggesting the need for a more cautious approach, especially while using them for a long term management. In benign airway disease, the stent should be removed as soon as healing has taken place.

Endotracheal Nitinol Stents

Objective

To reflect on lessons learned placing endotracheal nitinol stents in children.

Study Design

Case series with chart review.

Setting

Tertiary care children’s hospital.

Subjects and Methods

All children who underwent nitinol cervical tracheal stenting were included. Records were carefully reviewed for intraoperative and postoperative complications, management choices, outcomes, and factors that influenced results.

Results

Between 1999 and 2011, 7 children underwent 13 stent placements. Median follow-up was 5 years (range, 1-12 years). Six patients underwent stenting as a salvage procedure following open attempts at airway reconstruction. Four patients remain decannulated with their stent in place (median follow-up 7 years). The fifth patient had his stent removed endoscopically after 50 days because it became apparent that his obstruction was primarily laryngeal. The sixth child had his stent removed via a tracheal fissure after 14 months because of recalcitrant subglottic inflammation at the superior stent border. The seventh patient was decannulated for over 2 years but ultimately required tracheotomy replacement because of stenosis with the stent lumen. Complications included stent migration (23%), restenosis (29%), edema (29%), and granulation (57%).

Conclusion

Endotracheal nitinol stents provide a realistic opportunity for decannulation in children for whom other options have failed but should be reserved only as a salvage procedure in severely complicated airways. Our experience has taught valuable lessons about stent indications, sizing, characteristics, and deployment, as well as means to avoid and manage their complications.

First experience with biodegradable airway stents in children

PURPOSE

We here report our experience with biodegradable polydioxanone stents for tracheal narrowing in children.

DESCRIPTION

Eleven custom-made polydioxanone stents were implanted in 4 patients with airway narrowing due to external compression or intrinsic collapse. The median stent diameter was 9 mm (range, 6 to 14 mm) and median length was 15 mm (range, 13 to 70 mm).

EVALUATION

Narrowing was relieved initially in all cases. There was no bleeding or perforation after polydioxanone stent implantation. Size mismatching was a problem in 2 cases. Three patients needed repeat stenting after stent absorption. There was 1 death, unrelated to the stent implantation. All 3 survivors are in good clinical condition up to 12 months after first stenting.

CONCLUSIONS

This pilot study shows that polydioxanone stents offer an alternative to metallic or silastic stents for collapse or external compression of the trachea in children. They may avoid the need for permanent stenting and allow subsequent growth of the airway.

The role of rigid and flexible bronchoscopy in children

Bronchoscopy for paediatric respiratory disease is a routine procedure in paediatric pulmonology. Rigid bronchoscopy is now much less commonly used than flexible bronchoscopy. Technological advances have brought better picture quality and easier storage of video documentation. Indications with clear clinical benefit are congenital or acquired unexplained airway obstruction. In pulmonary infections or infiltrates in immunodeficient or immunosuppressed children not responding to empirical treatment a pathogen may be identified by bronchoscopy and bronchoalveolar lavage (BAL). Bronchoscopy and BAL can be indicated in children with unusual presentations of chronic cough or wheeze, and cystic fibrosis. The use of transbronchial biopsies (TBB) is established in paediatric lung transplantation. New applications and techniques are being developed, such as endobronchial ultrasound and transbronchial needle biopsy of lymph nodes and the role of airway stent placement have become better understood.

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.

Airway stents in children

Airway obstruction in children is a rare, but difficult clinical problem, with no clear agreement on optimal therapeutic approach. Stenting of the airway has been used successfully in adults, and is an attractive alternative in children. Fundamental differences of pediatric compared to adult use include the benign nature of most stenoses, the narrow and soft airways of children, the required long-term tolerance and adaptation to growth. These differences may significantly alter the therapeutic balance, calling into question the precise role stents play in the treatment of airway obstruction in children. Stent placement can be technically demanding but is not exceedingly difficult. Experience is necessary to select the proper size and type of stent. Metal stents usually achieve airway patency and clinical improvement in the majority of cases, while this is less frequently the case with silicone stents. Some complications such as granulation and secretion retention seem to occur in most children after stent implantation. Unfortunately, severe complications including death have been reported in a significant proportion of children. Stent related mortality can be estimated at 12.9% from published data, but these include complication centered reports. The initial euphoria for airway stents in children has largely abated and most authors agree that they should only be employed in circumstances with no good alternatives. It is crucial that all surgical and medical alternatives are considered and the decision to place a stent is not made because other options are overlooked or not available locally. Stent use in a palliative setting has also been reported and is probably reasonable. Stents will only allow limited adaptation for the growth of pediatric airways by balloon dilatation. All metal stents should be considered as potentially permanent, and removal sometimes may only be possible through a surgical and sometimes risky approach.

Expandable tracheal stenting for benign disease: worth the complications?

OBJECTIVES

To characterize the limitations of self-expandable stents in the management of benign tracheal stenosis, we performed a retrospective review at a tertiary care medical center.

METHODS

Patients who underwent tracheal stenting were assessed for the cause and severity of tracheal stenosis, comorbidities, stent-related complications, and follow-up airway procedures.

RESULTS

Sixteen adults (12 women, 4 men; mean age, 47 years) had a total of 26 stents placed for benign disease. Intubation-related stenoses were most frequent (81%). The average follow-up time was 20 months (range, 1 to 40 months). Each stent remained functional for an average of 12.4 months. In the study group, 87% had a complication that required surgical intervention to maintain a patent airway. The most common problem was granulation tissue formation at the ends of the stent causing airway restenosis (81%), and 5 patients (31%) required tracheotomy as a result of restenosis around the stent. Fourteen of the stents (56%) were removed or expelled from the patients.

CONCLUSIONS

The implantation of self-expandable stents is a minimally invasive method of managing benign tracheal stenosis. Although a small subset of patients may benefit from placement, the majority of patients have complications that require intervention to maintain a patent airway. Thoughtful discretion is critical in selecting patients for this intervention.

Placement of Covered Retrievable Expandable Metallic Stents for Pediatric Tracheobronchial Obstruction

PURPOSE

To evaluate the safety and clinical effectiveness of placement of covered retrievable expandable metallic stents in seven children with tracheobronchial obstruction.

MATERIALS AND METHODS

Using bronchoscopic and fluoroscopic guidance, stent placement was performed in seven children (median age, 12 y; range, 2 mo-14 y). The stents were electively removed 6 months after placement or whenever there were symptom-producing complications. During the follow-up period, technical and clinical success, complications and related reinterventions, and long-term prognosis were retrospectively evaluated.

RESULTS

Stent placement was technically successful for a total of eight stents in all seven patients. Stent removal was also successful for six stents in five patients; two stents were removed electively 6 months after placement, and four stents were removed due to symptom-producing complications. Clinical success defined as ventilator weaning, extubation, or dyspnea improvement was achieved in all patients 1 week after stent placement. A possible infection source in one stent and abundant granulation tissue caused by three stents necessitated removal of four stents in three patients. During the mean follow-up period of 18.7 months (range, 1-31 mo) after stent placement, three patients died due to the progression of underlying cardiopulmonary disease or malignancy. There were no deaths directly related to stent placement or related complications.

CONCLUSION

Although the findings were based on a small series, placement of covered retrievable expandable metallic stents seems to be safe and effective for the treatment of pediatric tracheobronchial obstruction. Ventilator weaning, extubation, or dyspnea improvement was possible in all patients after stent placement.

The role of the CO2 laser in the management of laryngotracheal stenosis: a survey of 100 cases

Over the last decade, improvement of CO2 lasers with the microspot and ultrapulse technologies has broadened the indications for endoscopic CO2-laser resection of benign laryngotracheal stenosis (LTS). This article reviews 100 patients treated solely by endoscopic means for a LTS. There were 47 grade III, 41 grade II and 12 grade I stenoses according to the Myer-Cotton classification. The postoperative results show that the improvement to a nearly normal (>80% luminal size) airway declines from 92% (11/12 patients) for grade I to 46% (19/41 patients) for grade II and 13% (6/47 patients) for grade III stenoses. When compared to open surgery for more severe grades of stenosis (31 grade IV, 66 grade III and 3 grade II stenoses), the results of the endoscopy group is much less favorable: 36% of patients in the endoscopy group versus 76% of patients in the open surgery group were rehabilitated to a normal respiration without exertional dyspnea and 38% versus 5% patients remained tracheotomy dependent. However, if strict selection and therapeutic criteria are respected, a significant number of grade I and II stenoses, and to a lesser degree of grade III stenoses, can be improved to a nearly normal airway by endoscopic means only. The endoscopic treatment is potentially less invasive and risky and only needs a short hospital stay. To try this as a first treatment modality in a selected group of patients is worthwhile, provided that this endoscopic treatment is not repeated a second time, if the stenosis recurs to its initial grade after a primary CO2-laser treatment. Some guidelines for safe endoscopic treatment modalities with of the CO2 laser, dilatation and/or stenting are proposed.