The large variety of potential indications for endobronchial stent placement are listed in Table 40-2. The majority of patients requiring tracheobronchial stents have malignant disease, most commonly bronchogenic carcinoma. A patient with an unresectable lung cancer and endobronchial tumor producing central airway obstruction may receive rapid and satisfying palliation by laser or core-out of the endobronchial disease. However, this requires patent distal airways and is not feasible when a tumor also produces obstruction at the
Table 40-2 Etiology of Obstructive Airway Lesions
Primary airway tumor Squamous cell Adenoid cystic Carcinoid Mucoepidermoid Miscellaneous Lung cancer
Renal cell carcinoma Breast cancer Colon cancer
Postintubation Cuff stenosis Stomal stenosis Idiopathic Anastomotic
Lung transplantation Sleeve resection/bronchoplasty Inflammatory Tuberculosis Histoplasmosis Wegener's granulomatosis Bacterial or fungal tracheitis Trauma
Tracheobronchial malacia Vascular compression
Postpneumonectomy syndrome Aortic aneurysm Pulmonary artery dilatation Miscellaneous
Tracheopathia osteoplastica Tracheobronchomegaly Relapsing polychondritis Compression by esophageal stent lobar and/or segmental levels. Proximal endobronchial tumor without distal lobar obstruction is the situation most amenable to airway palliation (Table 40-3). In these cases, airway stenting may prolong the period of palliation achieved by mechanical or laser reestablishment of the airway (Figure 40-2, [Color Plate 10]). In this setting, stenting may be reserved to palliate rapidly recurrent areas of an endobronchial tumor.
Patients with locally advanced lung cancer may also exhibit significant extrinsic compression of the airway, with or without concomitant endoluminal tumor. These patients may require urgent stenting to stabilize the airway while the primary tumor and bulky mediastinal lymph nodes are treated with systemic therapy or radiation. However, many times, these patients have already undergone definitive treatment and have recurrent or persistent airway compromise with impending suffocation. In these patients, airway stenting is the only treatment for the extrinsic airway compression, and can produce a gratifying improvement in quality of life and avoidance of death from airway obstruction (Figure 40-3 [Color Plate 10]).
Primary airway tumors such as squamous cell carcinoma, adenoid cystic carcinoma, and carcinoid tumors are most commonly treated with definitive surgical resection unless the length or extent of tumor involvement precludes operability. Radiation, with or without chemotherapy, is the usual second-line therapy for patients who are not candidates for surgical resection. However, patients with endobronchial obstruction are candidates for stent placement, both for stabilization of the airway during treatment, or for persistent airway stenosis after definitive therapy.
Adjacent primary tumors may produce airway obstruction by direct airway invasion or extrinsic compression (Figures 40-4A, 40-5, [Figures 40-4B and 40-5C through E, see Color Plates 10, 11]). Esophageal cancer, head and neck malignancies, and thyroid cancer may all result in tracheal obstruction that can be palliated by stent placement. Esophageal cancer may also result in a malignant tracheoesophageal fistula. These patients commonly have a short life expectancy, but the contamination of the airway by salivary and gastric contents may be minimized by a covered esophageal stent or covered tracheal stent, or both. Expandable endoesophageal stents have produced a marked improvement in the palliation of patients with malignant esophageal obstruction. However, when these stents are placed in the upper esophagus, they may result in a secondary extrinsic compression of the trachea or mainstem bronchi. If the esophageal stent cannot be removed, then the airway can be palliated with a second stent in the airway to maintain airway patency.
Several primary tumors are known to metastasize occasionally to the airway or to the paratracheal or subcarinal lymph nodes with secondary airway involvement (Figures 40-6 [Color Plate 11], 40-7) The most common of these is renal cell carcinoma, followed by breast cancer and colon cancer metastases. If these lesions are isolated to the central airways, with patent lobar and segmental orifices, then these patients are also candidates for laser and/or endobronchial core-out as previously described for central lung cancer. In these cases, extrinsic compression or rapid recurrence of endobronchial tumor is a strong indication for endobronchial stenting.
The most common etiology of benign tracheal stenosis is a postintubation injury resulting in either a cuff stenosis or a stomal stenosis. The vast majority of these patients are best treated by a tracheal sleeve resection as a definitive therapy with reliable results.3 Even patients with a high surgical risk because of medical comorbidities are usually best treated by definitive surgical correction rather than by broncho-scopic palliation or stenting, for several reasons. First of all, few benign stenoses are permanently corrected by dilatation, laser resection, or stenting. Second, tracheal resection and reconstruction is usually only a
Table 40-3 Anatomic Criteria for Airway Stenting
Distal to cricoid Proximal to lobar orifice Patent lobar/segmental orifices
neck operation, with a relatively trivial physiologic insult that is well tolerated by most patients. Third, patients with significant co-morbidities may not tolerate the often-repeated interventions that are necessary with palliative techniques, including stenting. However, some patients may refuse surgery and others may have a very long segment stenosis that is not amenable for surgical reconstruction. Other patients may benefit from temporary endoluminal stenting while maximizing conditions for a planned surgical correction. Rarely, patients with an early postintubation stenosis may remodel the airway over an indwelling tracheal stent that can ultimately be removed with a narrowed but adequate and stable airway.
Patients with traumatic airway disruption are not candidates for early stent placement and should have their tracheobronchial laceration corrected surgically. Likewise, patients with a benign stricture from trauma are best corrected with resection and primary reconstruction, as for patients with postintubation stenosis. However, these patients may also be candidates for stenting if the stricture is uncorrectable or if a stent is being used as temporary palliation in preparation for surgery.
figure 40-7 A, Metastatic renal cell carcinoma to subcarinal lymph nodes with both endoluminal and extrinsic obstruction of the right lung. B, Mechanical core-out of tumor with the tip of the rigid bronchoscope. C, Further debridement of the endoluminal tumor with biopsy forceps. D, Hemostasis and vaporization of the tumor bed with an Nd:YAG laser.
figure 40-7 (continued) E, Residual extrinsic compression of the bronchus intermedius after resection of the endo-luminal tumor. F, Silicone stent with flanges seated in the bronchus intermedius. G, Separate silicone stent with external studs seated in the mainstem bronchus. Note the medial intussusception and lateral separation to allow ventilation of the right upper lobe. This can be augmented by cutting the distal portion of the right mainstem stent at an angle to prevent obstruction of the right upper lobe orifice.
Idiopathic tracheal stenosis most commonly involves the very proximal trachea, often extending into the subglottic larynx. These patients may be palliated with periodic dilatation or definitively corrected with tracheal resection or reconstruction. Because of the anatomic location of these stenoses, idiopathic tracheal stenosis is generally not a good indication for airway stenting. This is because of the significant difficulty in seating a stent proximal to the cricoid into the subglottic larynx, as well as a significant risk of producing subglottic granulations that may actually extend and further complicate the original stenosis. If these patients do require airway stenting, then this is probably best accomplished using external stabilization with a tracheal T tube, as discussed in Chapter 39, "Tracheal T Tubes."
Anastomotic stenosis after lung transplantation, sleeve resections, and bronchoplastic procedures now provide a common indication for endobronchial stenting. Anastomotic complications occur in 4 to 15% of lung transplant anastomoses.25 Anastomotic stenoses occur due to technical complications, dehis-cence with subsequent granulation and cicatricial scarring, and ischemia. Ischemia can also occur distal to the anastomosis and can cause ischemic stricture of the bronchus intermedius after right lung transplantation. Other patients may develop secondary bronchomalacia due to ischemia, airway distortion, or steroids. Most of these patients are not candidates for direct surgical reconstruction or anastomotic revision and so provide a good indication for endobronchial stenting.
Anastomotic stricture after tracheal resection or bronchial sleeve resection is uncommon, occurring in approximately 5% of primary airway resections.3,26 Many of these patients may be candidates for reoperative surgical resection and reconstruction, but most of these patients benefit from a period of airway stenting to allow maturing of the fibrous scar to facilitate reoperative surgery.27 Many of these patients may no longer be surgical candidates for a variety of reasons, and provide further indications for prolonged endobronchial stenting.
Inflammatory or infectious conditions producing benign airway stenosis are infrequently appropriate for definitive surgical correction. The exceptions are the occasional patient with a short segment residual tracheal or bronchial stenosis after tuberculosis or a fungal or bacterial tracheitis, or from Wegener's granulomatosis in remission. The majority of these lesions, however, are best treated by dilation and endobronchial stenting, due to the extent of disease and the natural history of the underlying etiology. This is also true of a variety of miscellaneous causes of airway obstruction such as a relapsing polychondritis and tracheobronchomegaly.
Vascular compression of an adjacent airway may occur in the setting of post-pneumonectomy syndrome, aortic aneurysm, or marked pulmonary artery dilatation. In each of these cases, every attempt should be made to correct the underlying problem rather than using an airway stent simply to palliate the secondary consequences of an airway compression. Many would consider vascular compression of the airway to be a relative contraindication to stenting due to the concern of stent erosion and a fatal bron-chovascular fistula.
Finally, tracheobronchial malacia may result in functional airway obstruction in the absence of a fixed stenosis. Patients may have true loss of cartilaginous support or a functional malacia, with anterior-posterior collapse in patients with severe chronic obstructive pulmonary disease. This provides another indication for stenting, which may result in excellent palliation, although these patients have a difficult problem with stent seating due to the lack of a malignant or benign stricture.
In general, patients are candidates for endobronchial stenting when they have malignant or benign obstruction that is not amenable to definitive surgical correction (Table 40-4). Temporary stenting may also be useful to stabilize the airway during initiation or preparation for definitive therapy. It is important that the ability to place an airway stent does not become its primary indication. A large number of patients are best treated by definitive surgery, and many other patients benefit from other endobronchial therapeutics that provide reliable results without the disadvantages of an indwelling prosthesis.1
Table 40-4 Criteria for Airway Stenting
Surgically Correctable Lesions
Patient refuses surgery
Planned delay of surgical intervention
High surgical risk
Trial of airway remodelling
Surgically Uncorrectable Lesions
Extrinsic compression Recurrent stricture (after dilation) Recurrent endoluminal tumor Stabilization during chemoradiation Malacia
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