 |
|
 |
|
 |
|
 |
|
 |
|
 |
|
 |
|
 |
|
 |
|
 |
|
 |
|
Tracheobronchial Stenting
In certain situations patients with advanced lung cancer are no longer considered healthy enough for surgery, yet they have significant problems resulting from their inoperable cancer. Many times this can result in debilitating and even life-threatening shortness of breath, pneumonia and even death. For these patients, there is a significant role for stenting of the airways. It can alleviate the blockage of an airway from tumor and keep it open to allow that portion of the lung to be used. This decreases the chance of the development of pneumonia beyond the blockage and increases the amount of usable lung the patient has. Ultimately, this translates into a better quality of life for the patient.
Tracheobronchial stenting is indicated in benign and malignant obstruction of the airways resulting from cancer, strictures or malacia (a softening of the airways leading to collapse with rapid air movement). Cancers can either grow into the airway or compress it externally to block the flow of air.
The patient presenting with signs and symptoms of airway obstruction has their airway secured, if necessary, and then undergoes evaluation with a computerized tomography scan of the chest with intravenous contrast. This helps to characterize the lesion and allows the surgeon to plan the best approach for the patient's particular lesion.
There are several stent types. The original were cylindrical tubes of silicone with small studs (Figure 1). The next generation after that were Y-shaped silicone tubes for use at the carina (where the windpipe splits in two, one branch for each of the right and left lungs) (Figure 2). The Dynamic Y-Stent® is a combination silicon tube with metal struts that also has a Y-shape (Figure 3). It is also used for disease at the carina but has the added benefit of an internal metallic skeleton to hold open the airway. There are also bare metal stents that self-expand and the most recent version is a silicone coated metallic stent (Figure 4).
 |
 |
|
Figure1 |
Figure 2 |
|
 |
 |
|
Figure 3 |
Figure 4 |
The silicone stents have the advantage of being adaptable, solid, easy to re-position and remove and inexpensive. Their non-porous walls prevent tumor for growing into the wall of the stent. The body reacts very minimally to silicone as it is an inert material. The disadvantage of silicone stents is their initial delivery-it requires rigid bronchoscopy which can only be done under general anesthesia. Generally, they also have smaller inner diameters relative to their metallic counterparts.
Metallic stents have the advantage of easy delivery, which can be done without general anesthesia. They have larger internal diameters, and they conform to the shape of the airways better. Their disadvantages are that they are difficult to remove and tumor and granulation tissue can grow through their walls, except in the case silicone coated metallic stent.
Placement of these requires bronchoscopy to locate the tumor and fluoroscopy (live x-ray) to place external markers on the patient to denote the limits of the airway narrowing. These markers are then used to deploy the stent using fluoroscopy. The stent is then checked with the bronchoscope one final time and the patient is then typically extubated and awakened. It is recommended that they stay in the intensive care unit for close monitoring and frequent airway toilette overnight. If all is well, the patient may go home in a few days.
Complications of the stent include re-obstruction of the airway in question in up to 20% of cases. This is most often a result of progression of the cancer the patient may have. The stent can migrate from its position; this is rare occurring in only 5% of patents. This requires removal of the stent. The patient can also have retained secretions and cause an infection of the large airways. Finally, the patient's airway can be perforated, which is a surgical emergency. This is extremely rare, however.
Contraindications to stenting include inability to dilate the lesion to 50% of the inner diameter of the stent, allergies to the materials or an inability to pass the guidewire past the lesion.
Our institution has placed 18 stents in the past 9 months, with great success.
Areas of Specialty