Airway stents

Dr.Santosh Jha

DNB TraineeLilavati Hospital And ResaearchCentre.

INTRODUCTION

• Airway stents, also known as tracheobronchial prostheses, are tube-shaped devices that are inserted into an airway.

• They are usually placed bronchoscopically and can be used to treat a variety of large airway diseases.

PATIENT SELECTION

• Indications —• Malignant tracheobronchial obstruction in a patient who

is undergoing external beam radiation and/or chemotherapy.

• Malignant tracheobronchial obstruction that persists despite endobronchial resection and dilation.

• Postintubation subglottic stenosis that fails endobronchial resection and dilation.

• Benign tracheal or bronchial stenosis in a patient who is not a surgical candidate or for whom surgical resection is pending.

• Localized severe expiratory central airway collapse, such as tracheobronchomalacia or selected cases of excessive dynamic airway collapse of any etiology.

• Anastomotic stricture or dehiscence following lung or heart-lung transplantation.

• Tracheal- or bronchial-esophageal fistula.

Contraindications• Airways stents are generally inserted bronchoscopically using

either general anesthesia or procedural sedation. Thus, contraindications to bronchoscopy, general anesthesia, and/or procedural sedation are also considered contraindications to airway stenting.

• Airway stenting is also contraindicated prior to laser therapy, endobronchial electrocautery, or argon plasma coagulation because such therapies can burn or break airway stents .

• In contrast, external beam radiation therapy and brachytherapy are NOT contraindications to airway stenting

TYPES OF STENTS

• Stents are made from several different materials and are available in varying sizes and shapes.

• The main classes of stents are :

silicone stents metal stents hybrid stents.

Bolliger, CT, Mathur, PN, Beamis, JF, et al. Eur Respir J 2002; 19:365. Copyright © 2002 European Respiratory Society Journals Ltd

Silicon Stent

• Most commonly used to manage central airway obstruction.

• Firm, stable in high temperatures and able to repel water.

• Relatively inexpensive, well tolerated, do not break down, and resist extrinsic compression from tumor, enlarged lymph nodes, and circumferential fibrotic scars.

• undesirable quality: they tend to migrate more commonly than other types of airway stents and may require repeated bronchoscopic procedures for stent repositioning.

Metal stents

Advantages over silicone stents: Metal stents are usually inserted via flexible

bronchoscopy, which requires only topical airway anesthesia and procedural sedation.

Metal stents rarely migrate within the tracheobronchial tree.

Self-expanding metal stents may generate sufficient force to distend even the firmest of strictures, which is helpful if the airway cannot be dilated before stent insertion.

Disadvantages compared to silicone stents

• Greater risk of airway perforation due to their expansile force, which makes the proper selection of stent size essential.

• They are more difficult to remove or reposition following deployment; granulation tissue or tumor easily grows through the spaces between the uncovered metal struts, which may lead to obstruction.

• Metal stents are more expensive.

• Complications related to metal stents have prompted a black box warning from the United States Food and Drug Administration and most operators avoid their use in patients with benign strictures.

• When absolutely necessary, most operators will only use covered metal airway stents.

INSERTION TECHNIQUE

• Whenever a lesion amenable to stenting is identified, the distance from the vocal cords to the lesion, the length of the lesion, and the diameter of the lesion should be measured .

• The optimal airway stent (type and size) can be selected and insertion planned.

• The choice of an airway stent is usually based upon operator preference.

• Considerations include cost, availability, and experience. • Insertion of the airway stent may be part of a

bronchoscopic intervention (eg, dilatation, cryosurgery, electrosurgery, or laser resection) or may be done days or weeks later as a palliative measure if the lesion recurs.

FOLLOW-UP

• Any patient with an airway stent who develops new respiratory symptoms (eg, cough, dyspnea) should undergo bronchoscopy to determine whether the airway is patent and the stent is in the correct position.

• The role of surveillance bronchoscopy two to three months after stent placement is controversial because its yield in detecting major stent-related complications in asymptomatic individuals appears to be small.

COMPLICATIONS

• Most airway stents are well tolerated. The following complications can occur, but serious life-threatening complications are rare.

• A local inflammatory reaction can be provoked, resulting in the growth of granulation tissue at the proximal and distal ends of the stent. It is uncertain if corticosteroids given at the time of stent placement diminish the inflammatory reaction.

• Obstruction of the stent by accumulated respiratory secretions or recurrent tumor growth.

• Migration of the stent, usually due to a violent or persistent cough, tumor growth, or resolution of the extrinsic compression that maintained the stent in position.

• Airway wall perforation or stent rupture from self-expanding metal stents.

• Broken wires or metal fatigue (ie, decreased strength).

• Lower respiratory tract inflammation or infection.