CasMin Twine helical stent.
1
Central Message
The helical Niti-S airway stent shows promise as a more ideal prosthesis for the management of tracheobronchomalacia.
See Article page e51.
The first clinical deployment of a pediatric airway stent was in 1988 and was reported by Loeff and colleagues.
2
Since that time, an array of airway stents have developed to treat complex airway disease in children. Pediatric-specific applications of airway stents include use after tracheal reconstruction for congenital tracheal stenosis3
and for tracheobronchomalacia4
not responsive to medical therapy. However, the ideal pediatric airway stent has yet to be developed. The ideal airway stent for pediatric patients should be easy to place, should support the airway without the development of significant complications, and should be easy to remove to allow maximal growth of the airway.3
Potential stent-related complications include migration, granulation tissue formation, mucus formation, and infection,5
particularly when granulation tissue develops. Despite the wide array (metallic,6
silicon,7
bioabsorbable8
) of pediatric stents available, none of them is ideal. The known complications associated with these devices have led to a stent-related mortality rate as high as 12.9%.7
Furthermore, the radial force used to keep certain kinds of stents in place has been shown to damage the microcirculation and serves as the nidus for mucosal injury and subsequent granulation tissue formation.9
,10
In this issue of the Journal, Mondal and colleagues
11
present the results of a promising animal study looking at a novel airway stent, the helical Niti-S stent (Taewong Medical, Seoul, Korea), for the treatment of tracheobronchomalacia in children.11
Its helical design is similar to the CasMin-Twine helical stent1
used to treat canine tracheal collapse. The 2 types of helical stents share certain advantages. These include ease of deployment, limited mucus production, and focal mucosal changes limited to the areas of stent contact. The helical design provides radial support with substantially less mucosal contact and at a lower pressure. The results of the study by Mondal colleagues provide further evidence that the stent design provides less of a nidus for granulation tissue formation. This was also shown with the CasMin-Twine helical stent animal study. Where the 2 stents diverge is the novel removal tool associated with the helical Niti-S stent. Removal of the stent should allow optimal growth of the airway. A primary limitation of the study by Mondal colleagues is the short duration of therapy. After tracheal reconstruction for example, it can take 2 to 6 months for the airway to endothelialize.3
It remains to be seen whether the helical Niti-S stent will be as amenable to removal with longer durations of therapy. However, the early advantages of the helical Niti-S certainly seem to be taking us toward a more ideal pediatric airway stent.References
- New tracheal stainless steel pilot study: twelve month follow-up in a rabbit model.PeerJ. 2019; 7: e7797
- A new intratracheal stent for tracheobronchial reconstruction: experimental and clinical studies.J Pediatr Surg. 1988; 23: 1173-1177
- The role of airway stents in the management of pediatric tracheal, carinal, and bronchial disease.Eur J Cardiothorac Surg. 2000; 18: 505-512
- The use of balloon-expandable metallic stents in the treatment of pediatric tracheomalacia and bronchomalacia.Arch Otolaryngol Head Neck Surg. 1999; 125: 203-207
- Tracheal granulation tissue. A study of bacteriology.Arch Otolaryngol Head Neck Surg. 1991; 117: 538-541
- Balloon-expandable metallic stents in the management of tracheomalacia in neonates.J Thorac Cardiovasc Surg. 1995; 110: 1145-1148
- Airway stents in children.Pediatr Pulmonol. 2008; 43: 330-344
- Biodegradable airway stents: novel treatment of airway obstruction in children.Adv Clin Exp Med. 2019; 28: 961-965
- Pressures exerted by endobronchial devices.Anesth Analg. 2007; 104: 655-658
- Endoscopic treatment of tracheal stenosis.Thorac Surg Clin. 2014; 24: 27-40
- Preclinical evaluation of a pediatric airway stent for tracheobronchomalacia.J Thorac Cardiovasc Surg. 2021; 161: e51-e60
Article info
Publication history
Published online: April 18, 2020
Accepted:
April 3,
2020
Received in revised form:
April 3,
2020
Received:
April 3,
2020
Footnotes
Disclosures: The author reported no conflicts of interest.
The Journal policy requires editors and reviewers to disclose conflicts of interest and to decline handling or reviewing manuscripts for which they may have a conflict of interest. The editors and reviewers of this article have no conflicts of interest.
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- Preclinical evaluation of a pediatric airway stent for tracheobronchomalaciaThe Journal of Thoracic and Cardiovascular SurgeryVol. 161Issue 1Open Archive
- Response to comments on preclinical evaluation of a pediatric airway stent for tracheobronchomalaciaThe Journal of Thoracic and Cardiovascular SurgeryVol. 163Issue 2
- PreviewWe were pleased to read the commentaries by Bryant1 and Overbey and colleagues2 on our published preclinical evaluation of a pediatric airway stent.3 We are encouraged by their opinions and concur with their comments toward translating our technology for the treatment of malacic airways in pediatric patients.
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