The foremost cause of death in lung cancer patients who have exhausted all therapeutic options is, of course, suffocation. It is thus quite certain that the lives of these patients could be extended significantly if patency could be maintained. Endoluminal obstruc­tion can be removed using the YAG laser through an endoscope, but if extrinsic compression is involved, YAG resection, when feasible, only achieves tempo­rary relief at best.

Theoretically a stent is a straightforward way to maintain an airway in these patients. At first view the tracheobronchial tree would appear to lend itself well to intubation. Since the airways are naturally held open by a series of cartilaginous rings, endoscopy is an easy and safe procedure. The entire procedure, ie, laser resection and intubation, can be carried out under direct visual control. Unlike esophageal intu­bation, no guide wire is required and reflux is not a factor to be considered in evaluating functional results or choosing a construction material for the prosthesis.

In most previous reports the tubes used for trache­obronchial intubation were originally intended for other purposes such as tracheotomy or esophageal intubation. Likewise, our first cases were done with a modified version of the Montgomery T-tube. Having obtained fair results in these first attempts, we de­signed and had a prototype of a dedicated prosthesis manufactured. Silicone was chosen as the construction material because of its flexibility and compatibility with living tissue. canada pharmacy mall

Surprisingly, the irritating cough which was ex­pected as a result of this foreign body did not develop. Even when the prosthesis was positioned in contact with the carina, the patient complained of no foreign body sensation. In fact, coughing is associated only with migration and can thus be considered as a specific sign of this complication.

With regard to migration, several points need to be stressed. Prototypes with flanges on the upper and lower rims did not perform well. The studs on the surface are necessary to prevent displacement. Pre­vention of this potentially life-threatening complica­tion depends also on carefully measuring the lumen and choosing a prosthesis that fits snugly. The solution to displacement is to perform endoscopy as promptly as possible and replace the undersized stent by an appropriate model. With tumors, migration is seldom a problem because, unlike tracheal stenosis, they do not regress and thus the risk of loosening is low. A word of warning is, however, needed. An oversized prosthesis also is dangerous. Indeed, the larger the prosthesis, the greater the risk of injuring the vocal cords and the subglottic region during insertion. Furthermore, it would be logical to speculate that an oversized prosthesis would increase the risk of erosion of a large vessel. In this series, however, we did not encounter the latter complication.

Another complication which had been expected, but which occurred in only in two cases, was occlusion of the prosthesis by dried secretions in the prosthesis. In fact, this problem, which has been reported with the Montgomery T-tube, is usually the result of dry air being inhaled through the stoma. Apparently, when the trachea is not incised and air is normally humidified in the upper airways, the risk of drying is very low.

As with all forms of endoscopic treatment, the main advantages of palliative tracheobronchial intubation are that it is quick, repeatable and relatively noninva­sive, although general anesthesia is necessary. Unlike radiotherapy or palliative surgery, no convalescence is needed. If the prosthesis is properly selected, relief is immediate and durable.

Insofar as indications are concerned, our experience highlights several points. The best indications for indwelling stents are compressive tumors of the large airways. Interestingly, in this series placement, was easier and results better in the left main stem bron­chus.

For tracheal stenosis, questions remain as to when and how long an indwelling stent should be used. Assuming that stents can be used like Montgomery T- tubes, they would be an interesting alternative in cases involving stenosis that is inoperable because of age or associated complications or as a bridge to surgery in patients with an ongoing inflammatory process or associated pathologies that must be given priority treatment. According to our experience, intubation must last at least six months and up to a year in most cases. In this series we treated only two cases involving bronchial stenosis. Although it is impossible to draw any definitive conclusions, we obtained satisfactory results after six months in one of these patients with tuberculosis-related stenosis. The second is still under treatment.
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The presence of a stent can cause problems if intubation is required and the patient as well as his family should be thus advised. In a patient with a tracheal prosthesis, emergency intubation is always possible using a small caliber tube, but an endoscopic examination should always be performed after extu- bation.

In conclusion, the results of this series of 118 prostheses placed in the trachea or bronchi of 66 patients suggest that indwelling tracheobronchial in­tubation can be a valuable palliative technique for tumors causing extrinsic compression of the large airways. It also may be used for patients with benign conditions, eg, iatrogenic tracheal stenosis or bronchial stenosis. If the prosthesis is properly selected and fits snugly into the lumen, tolerance is excellent. Thus, this technique may extend the life of patients who have exhausted or have contraindications for other modalities. For example, it appears useful in patients with diffuse adenoid cystic carcinoma.