INTERVENTIONAL PULMONOLOGY IN OTHER JOURNALS: Commentary on Selected Publications
Tracheobronchial stenting for tuberculous airway stenosis.
Chest 2002;122:370–4. Wan IY, Lee TW, Lam HC, Abdullah V, Yim AP. Department of Surgery, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR, China.
This study reviewed the results of the use of Dumon silicone stents in patients experiencing tuberculous tracheobronchial stenosis since 1994, using a retrospective case review in a university teaching hospital with 1,450 beds serving a population of more than 1.8 million. Between February 1994 and September 2001, seven patients with tuberculous tracheobronchial stenosis were identified. These patients (6 women), had a mean age of 43 years (range, 17–61 years), and had both histologic and microbiologic documentation of either previous or current Mycobacterium tuberculosis infection. One patient had experienced blunt chest trauma and left main bronchial injury with resulting stenosis at the site of partial transection. Another patient had relapsing polychondritis with multiple strictures within the trachea and distal bronchial tree. She received multiple tracheobronchial stenting with silicone and flexible metal stents. Of the patients with tuberculous tracheobronchial strictures, five had experienced active tuberculosis on medical therapy, whereas two had a history of tuberculous infection more than 5 years ago. Five patients had left main bronchial stenosis, whereas two patients had stenosis of the trachea. These 7 patients underwent a total of 11 dilatations with placement of 10 straight stents and 1 Y stent. Under general anesthesia, all patients underwent rigid bronchoscopy and dilatation of the stenosis with placement of a Dumon stent. The stents that were inserted ranged from 9 to 16 mm in diameter and 3 to 4 cm in length. All patients experienced subjective improvement in symptoms with a mean dyspnea improvement score of 7.4 points after stenting. There was no mortality associated with this procedure. One patient developed a pneumothorax. Two patients with left mainstem bronchial stenosis experienced migration of the stent, which required reintervention for adjustment of the position of the stent. The stents were left in situ for a mean period of 32 months. The authors conclude that bronchoscopic dilatation with placement of a silicone stent is an effective treatment of patients with tuberculous tracheobronchial stenosis. Tuberculous tracheobronchial stenosis is uncommon in the West. A review of publications on endobronchial tuberculosis reveals that a substantial number of patients with this problem are of Oriental origin. In Hong Kong, the incidence has been reported to be as high as 18% in patients with parenchymal tuberculosis (Tubercle 1982;63,195–200). Wan et al. indicate that in Hong Kong, endobronchial tuberculosis with airway stenosis remains a common cause of benign tracheobronchial stenosis. In a study reported from Korea, 45 of 81 patients (56%) developed fibrostenotic lesions (Chest 2000;117:385–92). In addition, new lesions appeared in two patients, and the size of the initial lesions increased in another two patients, even at 6 months after treatment. The mechanisms responsible for the development of endobronchial tuberculosis may include direct implantation of tubercle bacilli into the bronchus from an adjacent pulmonary parenchymal lesion, direct airway infiltration from an adjacent tuberculous mediastinal lymph node, erosion and protrusion of an intrathoracic tuberculous lymph node into the bronchus, hematogenous spread, and extension to the peribronchial region by lymphatic drainage. Endobronchial tuberculosis is misdiagnosed frequently as bronchial asthma or lung cancer. Tumorous endobronchial tuberculosis is characterized by an endobronchial mass with a surface that is often covered with caseous material. These lesions can nearly totally occlude the bronchial lumen. This form of endobronchial tuberculosis is frequently mistaken for lung cancer because of the bronchoscopic appearance and the computed tomographic findings that mimic lung cancer. However, when flexible bronchoscopy is performed for the diagnosis of cancer in populations with a low prevalence of tuberculosis, routine collection of specimens for cultures of mycobacteria is not warranted (J Bronchol 1999;6:236–40). The fact that more than 50% of patients with endobronchial tuberculosis eventually develop stenotic bronchial lesions, despite antituberculous therapy, is noteworthy. However, controversies still exist concerning the use of intraluminal stenting as the definitive management strategy for benign tracheobronchial stenosis. The timing of intervention is also controversial, and there is no way to predict which patient will develop endobronchial tuberculosis with residual strictures or when that patient will develop the condition. The role of systemic or intralesional steroid therapy in the prevention of tuberculous bronchial stenosis remains unclear. Critical airway stenosis may require bronchoscopic dilatation, laser therapy, or airway stent placement (J Bronchol 1999;6:159–65). Surgical treatment, with lung resection or complex tracheobronchoplasty, has been the established treatment of patients with airway strictures secondary to tuberculosis.