Benign and Malignant Tracheobronchial Strictures:Long Term Follow-up of Treatment with Polyurethane-Covered Retrievable Expandable Nitinol Stents strictures

PURPOSE: To assess the safety and long term effectiveness of polyurethane-covered retrievable expandable nitinol stents in the treatment of benign and malignant tracheobronchial strictures. MATERIALS AND METHODS: Under fluoroscopic guidance, the stents were placed in 32 patients with dyspnea whose strictures were malignant in 15 cases and benign in 17. A stent was removed when complications occurred,or -electively- 2-6 months after placement in patients with benign strictures. The range of follow-up period was 1 -98 weeks (median, 47; range, 50) weeks. RESULTS: Stent placement was well tolerated in 30 patients. After placement, all 32 showed immediate symptom improvement and in none were complications such as ingrowth of a tumor or granulation tissue observed during the follow up period. Stent migration occurred in six patients. In one of six and four of five patients from whom, respectively, stents had been electively removed two and six months after placement, tracheo-bronchial restenosis did not occur during follow up. Second stents were placed in six patients in whom dyspnea recurred due to restenosis after elective stent removal. In two of these six, stents were removed six months after placement and dyspnea did not recur during follow up. CONCLUSION: The use of covered retrievable tracheobronchial stents is safe and feasible in the conservative treatment of patients with malignant tracheobronchial strictures as well as for selected patients with benign strictures.

Endobronchial Metastasis: CT Findings and Its Usefulness in Bronchoscopic Correlation

PURPOSE: To evaluate the CT findings of bronchial abnormalities in patients with endobronchial metastasis from extrapulmonary tumors, and to correlate these with the bronchoscopic findings. MATERIALS AND METHODS: The authors retrospectively reviewed the CT and bronchoscopic findings of 17 patients (M:F=9:8; mean age, 56 years) with histologically proven endobronchial metastasis from extrapulmonary primary tumors. Carcinoma of the uterine cervix (n = 5) was the most common primary site for endo-bronchial metastasis. CT findings of bronchial abnormalities with associated peribronchial and lung parenchymal lesions were analyzed and compared with the bronchoscopic findings. RESULTS: Among the 17 patients, 20 sites of bronchial abnormalities were visualized bronchoscopically. CT findings of bronchial abnormalities were smooth narrowing (n = 11), occlusion (n = 3), intraluminal mass (n= 4), and normal (n = 2). Peribronchial lesions(lymph node enlargement or parenchymal mass) were found in 12 cases. Bronchoscopy revealed bronchial narrowing due to a mucosal nodule or intraluminal polypoid mass in 16 cases, and total obstruction of the bronchus in four. With regard to the identification of bronchial abnormalities, the findings of CT and of bronchoscopy agreed in 17 cases and disagreed in three. While bronchoscopy was advantageous for detecting early mucosal abnormality, CT effectively evaluated the extent of a lesion beyond the stenosis or bronchial obstruction. CT was also useful for predicting the causes of bronchial abnormalities. CONCLUSION: CT is relatively accurate in evaluating bronchial abnormalities, and in patients with endo-bronchial metastases may be used as a complementary procedure to bronchoscopy for evaluating the extent of the lesion.

A Retrievable Nitinol Endobronchial Stent: An Experimental Study in Dog

PURPOSE: The purpose of this study was to evaluate the safety and the retrievability of a new coveredretrievable nitinol tracheobronchial stent. MATERIALS AND METHODS: Stents were knitted from 0.2mm nitinol wire,covered with polyurethane, and were 20 -22mm in diameter and 2cm in length. Under fluoroscopic guidance, a stentwas placed in the normal right bronchus intermedius of ten dogs. Using a retrieval hook, stent retrieval wasattempted after 1 month(N=5) or 2 months(N=5). After removal, the dogs were sacrificed and their tracheobronchialtrees were examined grossly and histologically. RESULTS: Eleven stents were successfully placed in ten dogs.Migration and expectoration occurred in four of ten stents in nine dogs(40%). Five stents were successfullyremoved from six dogs(83%). Without significant difference between the two groups, mild to moderate mucosalhyperplasia was noted at the sites of stents as well as above and below them. On microscopy, three of five dogsshowed pneumonia in the right middle lobes, but none of the stents was covered with epithelium. CONCLUSION:Temporary placement of a covered expandable nitinol stent in the tracheobronchial tree is feasible, but toestablish its efficacy, further experimental studies are needed.

Expandable Metallic Stents in the Palliative Treatment of Malignant Tracheobronchial Stenosis

PURPOSE: To report the outcome of using expandable metallic stent in the management of malignanttracheobronchial stenosis with dyspnea. MATERIALS AND METHODS: Under fluoroscopic and bronchoscopic guidance,seven patients with malignant airway stenosis were treated with ten expandable metallic stents. The cause ofstenosis was metastasis from esophageal cancer in five patients, recurrent adenoid cystic carcinoma of the tracheain one, and primary lung cancer in one. The major sites of obstruction were the trachea in four patients, the leftmain bronchus in one, the trachea and left main bronchus in one, and the trachea and both bronchi in one. Chestradiography(n=7), bronchoscopy(n=5), pulmonary function test(PFT)(n=3), and spirometry(n=1) were performed beforeand after stent placement. RESULTS: In all seven patients, the stent was successfully placed at the lesion sitesand dyspnea began to improve immediately. After the procedure, chest radiography and bronchoscopy showed anincrease in airway diameter. After stent placement, forced vital capacity (FVC) and forced expiratory volume inone second(FEV1) improved 53% and 56%, respectively. Peak flow velocity also changed from 46 L/min to 200 L/min.During median follow-up of 67(41-1565)days, one stent migration occurred. In one patient, proximal tumorovergrowth occurred, and in one, tumor ingrowth was treated with balloon dilatation. CONCLUSION: For in thepalliative treatment of malignant tracheobronchial stenosis with dyspnea, placement of expandable metal steuts issafe and effective.

Balloon Dilatation of Tuberculous Bronchial Stenosis :Immediate and Long Term Effect

PURPOSE: To evaluate the long-term immediate effects of balloon dilatation of the tuberculous bronchial stenosis. MATERIALS AND METHODS: Twenty-three women with tuberculous bronchial stenosis (19, left main bronchus ; 4, right main bronchus) underwent balloon dilatation (13 bronchoscopically guided ; 10 fluoroscopically guided). Immediate (n=23) and long-term follow-up (mean, 17.2 months; range, 1 month-6years 3 months; n=20) assessments focused on changes in the results of the pulmonary function test (PFT). An increase in FVC or FEVI of more than 10% after the procedure was considered effective. in all patients, any complications were evaluated. RESULTS: Balloon dilatation was effective at immediate follow-up in 69.5% of patients(16/23) and in 75.0%(15/20) atlong-term follow-up. Bronchoscopically and fluoroscopically-guided balloon dilatation proved effective in 61/5%(8/13) and 80.0% of patients (8/10) on immediate follow-up respectively, but in 90.0%(9/10) and 60/0%(6/10)on long term folow-up respectively. Balloon dilatation was effective in the active(n=10) and inactive(n=13) stage of tuberculous bronchitis in 80.0%(8/10) and 61.5% of cases(8/13) on immediate follow-up respectively, but in 66.6%(6/9) and 81.8%(9/11) on long term follow-up study, respectively. CONCLUSION: On immediate follow-up, balloon dilatation of tubular bronchial stenosis was more effective in the active than in the inactive stage, buton long-term foolow-up was less effective; long-term improvement in the inactive stage was, however, well-maintained.

Respiratory Dynamic CT: Functional Evaluation of Main Bronchial Stenosis

PURPOSE: To separately evaluate the respiratory function of both lungs separately in patients with unilateralmain bronchial stenosis or obstruction, applying respiratory dynamic CT using the spiral technique. MATERIALS AND METHODS: This study involved five normal subjects and six patients with main bronchial stenosis. Time-continuous scan data at a selected levels during forced vital capacity maneuver were obtained, and static images were retrospectively reconstructed using 0.67 sec. partial scan data per image. Time-density curves for controls and patients were plotted and compared. RESULTS: The highest values of mean attenuation were -697+/-9 H for the leftlung and -684+/-9 H for the right lung of controls, and -697+/-5HU for the healthy lung and -791+/-3H for thediseased lung of the patients. The lowest values were -837+/-2H for the left lung and -842+/-5H for the right lungof contorls, and -847+/-0H for the healthy lung and -858+/-4H for the diseased lung of patients. Mean durations ofexpiration were 1.64+/-.65 seconds for the left lung and 1.58+/-.50 seconds for the right lung of controls, and1.66+/-.60 seconds for the healthy lung and 1.96±.49 seconds for the diseased lung of patients. Time-attenuationcurves for the right and left lung of controls were not significautly different, but except for the lowest value of mean attenuation, these were signficantly different for the healthy and diseased longs of patients. CONCLUSION: Respiratory dynamic CT is an updated technique which permits imaging of the functional status of lung parenchy maduring respiration. It may be useful in the evaluation and quantification of lung function in patients with proximal airway stenosis.