Management of malignant tracheobronchial stenosis with metal stents and Dumon stents

Tracheobronchial stents in patients with malignant airway disease: Finnish tertiary care experience

OBJECTIVES

Tracheobronchial stenting has an established role in the palliation of malignant central airway obstruction (CAO). The purpose of this study is to describe the experience with self-expanding metal airway stents in 2 tertiary referral centres, covering a third of the population of Finland.

PATIENTS AND METHODS

Patients referred to and treated with airway stenting for malignant CAO using self-expanding metal-stents were identified from electronic patient records, and data were collected using a structured Endoscopic Lower Airway Management instrument. Statistical analysis to reveal factors affecting patient benefit and survival was carried out.

RESULTS

A total of 101 patients (mean age 65.8) and 116 procedures were identified. Procedure-related mortality was rare (3/101 patients) and complications infrequent. The median survival was 2.3 months [95% confidence interval (CI): 1.4-3.1). Stent benefit was not significantly affected by clinical characteristics. Survival was impacted by the use of adjunct procedures [hazard ratio (HR) 0.36, 95% CI: 0.23-0.58, P < 0.001), procedural urgency (HR 0.40; 95% CI: 0.23-0.71, P = 0.002) and post-treatment chemoradiotherapy (HR 0.29, 95% CI: 0.15-0.56, P < 0.001).

CONCLUSIONS

The beneficial impact observed supports the further use of tracheobronchial stenting in malignant CAO. The use of self-expanding metal stents is encouraged.

[Use of Hybrid Stent in Management of Complex Malignant Airway Stenosisand Fistulas]

背景与目的

气道内支架广泛应用于气管狭窄和气管瘘的治疗，但使用气道内支架重建复杂气道的临床数据仍不充足。硅酮支架杂交金属支架重建复杂气道的有效性和安全性。

方法

纳入无法手术的复杂恶性气道狭窄和气道瘘患者。使用Y型硅酮支架联合金属覆膜支架（杂交支架）重建气道。评价置入支架后6个月的疗效和并发症。

结果

共纳入23例患者，置入23枚Y型硅酮支架和25枚金属覆膜支架。19例患者（19/23, 82.6%）置入支架后症状迅速缓解。支架平均置入（153.43±9.14）d。置入支架后改良呼吸困难指数（modified British Medical Research Council, mMRC）、卡氏功能状态（Karnofsky performance status, KPS）评分和功能状态（performance status, PS）评分显著改善。12例患者带支架生存超过6个月。其余患者肿瘤进展导致6个月内死亡。无支架置入相关死亡及严重并发症。

结论

杂交支架重建恶性复杂气道疗效确切，耐受良好。

Evaluation of the Effect of a Tracheal Stent on Radiation Dose Distribution via Micro-CT Imaging

PURPOSE

To study the effect of a metal tracheal stent on radiation dose distribution.

METHOD

A metal tube bracket is placed in a self-made foam tube sleeve, and micro-computed tomography scanning is performed directly. The foam sleeve containing the metal bracket is placed in a nonuniform phantom for a routine computed tomography scan. The stents in conventional computed tomography images are replaced by the stents in micro-computed tomography images. Subsequently, 2 sets of computed tomography images are obtained and then imported to a radiotherapy treatment planning system. A single photon beam at 0° is designed in a field size of 10 cm × 10 cm, a photon beam of 6 MV, and a monitor unit of 200 MU. Monte Carlo algorithm is used to calculate the dose distribution and obtain the dose curve of the central axis of the field. The dose is verified with thermoluminescence dose tablets.

RESULTS

The micro-computed tomography images of the tracheal stent are clearer and less false-like than its conventional computed tomography images. The planned dose curves of the 2 groups are similar. In comparison with the images without any stents in place, the doses at the incident surface of the stent in the conventional computed tomography images and at the stent exit surface in the rear of the stent increase by 1.86% and 2.76%, respectively. In the micro-computed tomography images, the doses at the incident surface of the stent and at the exit surface behind the stent increase by 1.32% and 1.19%, respectively. Conventional computed tomography reveals a large deviation between the measured and calculated values.

CONCLUSION

Tracheal stent based on micro-computed tomography imaging has a less effect on radiotherapy calculation than that based on conventional computed tomography imaging.

The technique of endoscopic airway tumor treatment

More than half of primary lung cancers are not resectable at diagnosis and 40% of deaths may be secondary to loco-regional disease. Many of these patients suffer from symptoms related to airways obstruction. Indications for therapeutic endoscopic treatment are palliation of dyspnea and other obstructive symptoms in advanced cancerous lesions and cure of early lung cancer. Bronchoscopic management is also indicated for all those patients suffering from benign or minimally invasive neoplasm who are not suitable for surgery due to their clinical conditions. Clinicians should select cases, evaluating tumor features (size, location) and patient characteristics (age, lung function impairment) to choose the most appropriate endoscopic technique. Laser therapy, electrocautery, cryotherapy and stenting are well-described techniques for the palliation of symptoms due to airway involvement and local treatment of endobronchial lesions. Newer technologies, with an established role in clinical practice, are endobronchial ultrasound (EBUS), autofluorescence bronchoscopy (AFB), and narrow band imaging (NBI). Other techniques, such as endobronchial intra-tumoral chemotherapy (EITC), EBUS-guided-transbronchial needle injection or bronchoscopy-guided radiofrequency ablation (RFA), are in development for the use within the airways. These endobronchial interventions are important adjuncts in the multimodality management of lung cancer and should become standard considerations in the management of patients with advanced lung cancer, benign or otherwise not approachable central airway lesions. We aimed at revising several endobronchial treatment modalities that can augment standard antitumor therapies for advanced lung cancer, including rigid and flexible bronchoscopy, laser therapy, endobronchial prosthesis, and photodynamic therapy (PDT).

Self-expanding y stent for the treatment of malignant tracheobronchial stenosis. Retrospective study

Palliation of malignant tracheobronchial stenosis is challenging. Published experience with self-expanding Y-shaped stents is limited and it seems necessary to evaluate whether they improve clinical results with respect to alternative prostheses. We present a retrospective case series of 20 consecutive patients with malignant tracheobronchial stenosis that underwent placement of a single-unit, Y-shaped covered metallic stent. Outcomes were: safety of the procedure, palliation of dyspnea, complications, and survival. All stents were safely and easily placed using a rigid tracheoscope within 24hours of admission. Dyspnea was effectively palliated in all patients, and no early or late adverse stent-related events were observed. Thirty-day mortality was 40%. Median survival was 12.2 weeks. Placement of Y-shaped self-expanding stents is a safe and effective procedure for the palliation of malignant tracheobronchial stenosis, and is currently our stent of choice for this subgroup of patients.

The insertion of self expanding metal stents with flexible bronchoscopy under sedation for malignant tracheobronchial stenosis: a single-center retrospective analysis

OBJECTIVE

To describe a 10-year experience of inserting Ultraflex™ self-expanding metal stents (SEMS) under sedation using flexible bronchoscopy for the treatment of malignant tracheobronchial stenosis in a tertiary referral centre.

METHODS

Medical notes were retrospectively reviewed for all patients who underwent SEMS insertion between 1999 and 2009.

RESULTS

A data analysis of 68 patients who had Ultraflex™ SEMS inserted under sedation was completed. Thirty three males and 35 females with a mean age of 67.9 years (range 35-94) presented with features including dyspnea/respiratory distress (39 patients), stridor (16 patients) and hemoptysis/dyspnea (13 patients). Etiology of stenosis included lung cancer (46 patients) esophageal cancer (14 patients) and other malignancies (8 patients). Mean dose of midazolam administered was 5mg (range 0-10mg). The trachea was the most common site of stent insertion followed by the right and left main bronchus, respectively. Adjuvant laser therapy was applied at some stage in 31% of all cases, and chemotherapy and/or radiotherapy was administered to at least 64% of patients with malignant disease. Hemoptysis and stent migration were the most frequent complications (5 and 4 patients, respectively). The mean survival time of stented non-small cell lung cancer (NSCLC) patients was 214 days (range 5-1233) and that of esophageal malignancy was 70 days (range 12-249). Mean pack-year history of individuals with lung cancer requiring stent insertion was 37 (range 2-100).

CONCLUSION

Ultraflex stents offer a safe and effective therapy for patients who are inoperable or unresectable that otherwise would have no alternative therapy. It has an immediate beneficial effect upon patients, not only through symptom relief but, in some, through prolongation of life. Survival data is no worse than other studies using different varieties of stents and insertion techniques indicating its longer-term efficacy. Moreover, this report highlights the feasibility of performing this procedure successfully in a respiratory unit, without the need for general anesthesia.

MECHANICAL TEST PROTOCOLS TO EVALUATE POLYMERIC TRACHEOBRONCHIAL STENTS

Tracheobronchial stents are used in the treatment of inoperable stenoses of the respiratory tracts and their purpose is to restore patency to the stenosed conduits or to provide scaffolding to these channels when they are weak. In this paper, the laboratory protocols to evaluate the mechanical properties of polymeric tracheobronchial stents, such as migration, collapsibility, distending strength and surface finish, are described. These are issues of concern when applying polymeric tracheobronchial stents in the palliation of stenosed airways. Using these test methodologies, comparisons are made between the mechanical properties exhibited by two commercially available polymeric stents and a new prototype polymeric stent.

The use of metallic expandable tracheal stents in the management of inoperable malignant tracheal obstruction

Tracheal neoplasms account for less than 1% of all malignancies. In spite of their low incidence, these tumors represent potentially lethal phenomena. In cases of airway compromise and unresectable disease, the airway may be maintained by repeated bronchoscopic debulkings, and the use of CO(2) laser, silicone Montgomery T-tube and tracheal stents. The use of metallic expandable stents to relieve airway obstruction in advanced tracheal tumors was previously reported. Our aim was to evaluate the use of metallic expandable tracheal stents as a palliative relief from severe airway obstruction in cases of locally advanced, inoperable malignant tracheal tumors. Patients suffering from severe airway obstruction secondary to locally advanced tracheal tumors, who presented to the Otolaryngology Head and Neck Surgery and Chest Diseases Departments at the Main Alexandria University Hospital, Egypt, were included in this study. After endoscopic and radiological evaluation, expandable metallic tracheal stents (SENS; Ultraflex tracheal prosthesis; Boston Scientific Corp, Watertown, MA, USA) were inserted under general anesthesia to relieve airway obstruction. Postoperative follow-up with regard to improvement of respiration, tolerability of the stent and reporting of complications was done. Twelve patients were included, eight males and four females with a mean age of 61 years. Four patients (33.3%) had primary tracheal tumors and eight (66.7%) suffered from tumors infiltrating the trachea from nearby structures. The stent was easily inserted in all patients with no significant intraoperative complications. Postoperatively, the stent was well tolerated and all patients experienced good respiration with significant improvement of respiratory function test results. The most common complication reported was granulation tissue formation. Other complications were displacement of the stent, bad breath, re-growth of tumor tissue at the lower end of the stent and retention of secretions. We concluded that Ultraflex self-expandable stent is a good alternative for palliative relief from airway obstruction in cases of inoperable malignant tracheal tumors. Strict follow-up is mandatory for early detection and management of expected complications.

Outcomes of airway stenting for advanced lung cancer with central airway obstruction

Approximately 30% of lung cancer patients will develop central airway obstruction (CAO). Interventional therapeutic bronchoscopy including airway stenting (AS) providing immediate and effective palliation is therefore essential to improve quality of life (QoL). However, no report has demonstrated the survival benefit of AS. We retrospectively reviewed 65 patients with CAO due to lung cancer who underwent AS from June 1994 to May 2008. Seventy-nine stents were required. Silicon, metallic, or both stents were placed in 42 (60%), 19 (29%), or eight (11%) patients, respectively. Single stent was required in 53 (83%) patients, double in 10 (14%), and triple in two (3%). AS could provide acute relief of central airway and significant improvement was seen in 98% of patients. Fifty-nine patients with detailed observations were assessed further. Morbidity and mortality rates were 22% and 8%, respectively. AS resulted in 25.2% of one-year survival rate and 6.2 months of median survival time (MST). AS followed by adjuvant therapy provided a four-month increase in MST, although overall survival was not significantly changed. This study represents a single-institution experience. Although an aggressive strategy of AS is justified in order to improve symptoms and QoL, AS itself did not contribute to survival benefit.

Outcomes of tracheobronchial stents in patients with malignant airway disease

BACKGROUND

Malignant central airway obstruction is difficult to manage and is associated with poor outcome. We sought to identify the short (< 30 days) and intermediate (> 30 days) benefits and risks of tracheobronchial stents in patients with malignant airway disease.

METHODS

Two hundred and twenty-five tracheobronchial stents were placed in 172 patients for benign (n = 32) and malignant (n = 140) disease from January 1, 1997, to May 31, 2003. The records of the patients with malignant disease were retrospectively analyzed to determine complication rate, reintervention rate, and survival. The malignant diagnoses included nonsmall cell cancer, small cell cancer, esophageal cancer, and metastatic disease.

RESULTS

There were 172 stents placed in 140 patients with malignant disease, with no intraoperative mortality. The mean follow-up period was 142 +/- 12 days. There were 23 complications, including tumor ingrowth (n = 9), excessive granulation tissue (n = 7), stent migration (n = 5), and restenosis (n = 2). Five of the complications occurred during the short-term period (< 30 days) with the remaining complications (n = 18) occurring after 30 days. The complications required interventions including laser debridement (n = 14), dilation (n = 4), and stent removal (n = 5).

CONCLUSIONS

Tracheobronchial stents offer minimally invasive palliative therapy for patients with unresectable malignant central airway obstruction. The benefit of airway stents is particularly seen in the short-term period where they provide symptomatic improvement and have low complication risk. The major impediment is excessive granulation tissue and tumor ingrowth, which occur primarily after 30 days.

Use of the Dumon Y-stent in the management of malignant disease involving the carina: a retrospective review of 86 patients

OBJECTIVE

To study the efficacy of symptom relief and the safety of the Dumon Y-stent for central airway obstruction in malignant main carinal involvement and in malignant tracheoesophageal fistulas.

DESIGN

A retrospective review.

SETTING

Thoracic endoscopy referral center.

PATIENTS AND METHODS

The medical records of 86 patients who had undergone the placement of a Dumon Y-stent at our institution were reviewed and analyzed.

RESULTS

Ninety Dumon Y-stents were placed in 86 patients to relieve symptoms of dyspnea, cough, and/or hemoptysis. Four of these patients required removal of that stent and replacement with a longer Dumon Y-stent due to tumor progression. There were only two instances of procedure-related adverse effects, which included coughing following stent placement lasting 1 week in one patient and stent migration in another patient. In the case of stent migration, the stent required immediate removal, and the patient experienced no adverse consequences. The remaining patients tolerated the stent well, and all experienced subjective symptomatic relief. There were no stent-related deaths. The average duration of a stent after placement was 133 days. The median time of survival following stent insertion was 181 days. Forty-five percent of all patients died at 3 months, and 72% died at 6 months.

CONCLUSION

The Dumon Y-stent proved to be useful and was well-tolerated in the management of malignant disease involving the main carina. It also provided successful palliation in patients with malignant tracheoesophageal fistulas.

Airway stenting for unresectable esophageal cancer

Because of the close anatomical relationship between the upper esophagus and the tracheobronchial tree, many patients with advanced esophageal cancer will suffer from airway complications. These include airway stenosis or esophago-respiratory fistulation. Airway stenting is proven to offer effective palliation for patients with both these complications. When managing such patients, the thoracic surgeon faces different options in terms of pre-stenting investigation, choice of stents and stenting strategy. Although airway stenting is a safe and effective procedure in experienced hands, there are nonetheless complications which await the unwary. This review discusses the currently available options for airway stenting in these patients, and offers practical advice on avoiding the pitfalls.

Efficacy and Safety of a Retrieval Hook for Removal of Retrievable Expandable Tracheobronchial Stents

PURPOSE

To evaluate the efficacy and safety of use of a retrieval hook for removal of retrievable expandable tracheobronchial stents.

MATERIALS AND METHODS

With fluoroscopic guidance, a retrieval hook was used to remove 45 retrievable expandable tracheobronchial stents in 31 patients. Indications for stent removal included tissue hyperplasia (n = 16), stent migration (n = 10), stent misplacement (n = 2), tumor overgrowth (n = 2), persistent gastrobronchial fistula (n = 1), and incompletely expanded stent (n = 1). Thirteen stents were electively removed after temporary use. The success rate, causes of failure, and complications related to stent removal with a retrieval hook were analyzed.

RESULTS

Forty-one of 45 stents (91.1%) were successfully removed with a retrieval hook. The following difficulties were encountered: disruption of the polyurethane membrane (n = 3) and an untied drawstring (n = 1). The removal procedure failed in four cases (8.9%) because of excessive tissue hyperplasia (n = 4) in the proximal portion of the stent. The hook wire fractured in two of the four failed cases. The overall complication rate was 4.4% (minor bleeding, n = 2).

CONCLUSION

For complications with or temporary use of retrievable expandable tracheobronchial stents, removal with a retrievable hook shows promising initial results.

Bronchoscopic insertion of Gianturco stents for the palliation of malignant lung disease: 10 year experience

Malignant large airway obstruction is life threatening and may not be amenable to urgent radiotherapy. Palliative airway stenting is difficult and traditionally carried out under general anaesthesia and fluoroscopy. We have shown that self expanding Gianturco metal stents can be placed under local anaesthesia using fibreoptic bronchoscopy and direct vision for the treatment of malignant airway tumours, and report our 10 year experience. All referrals for stenting referred to our unit between 1990 and 1999 were included, looking for histological type, number and site of stents, complications of the procedure, other interventions, and survival. One hundred and sixty two patients (average age 64 years, (range 21-89)) had 307 stents inserted during 167 procedures (144 primary lung tumours, 18 secondary malignancy). There were no operative deaths, but three patients developed a pneumothorax, one requiring intercostal drain insertion. Average survival following stent insertion was less for primary lung cancer than for secondary disease (103 vs. 431 days, P<0.001). There were no excess complications in a subgroup of 64 patients treated locally by oncologists, even when stenting was the primary procedure. This technique is useful in palliating life threatening airway obstruction, particularly for secondary cancer, and can be used in any centre undertaking fibreoptic bronchoscopy.

High dose rate brachytherapy in the management of lung transplant airway stenosis

BACKGROUND

Airway complications after lung transplantation remain a major cause of postoperative morbidity and mortality. Interventional bronchoscopic management continues to be the main modality in the management of these problems.

METHODS

Four patients with airway stenoses after lung transplantation received high dose rate brachytherapy for management of recurrent stenosis. All 4 patients had been treated with various bronchoscopic interventions, including dilation and stenting, electrocautery ablation, and neodymium:yttrium-aluminum-garnet laser therapy. High dose rate endobronchial brachytherapy was subsequently used in all 4 patients for management of recurrent airway obstruction. The radiation dose for all 4 patients was 3 Gy at a distance of 1 cm from the center of the catheter.

RESULTS

All four patients have had routine follow-up after endobronchial brachytherapy treatments. Of the 4 patients, 2 treated with this modality showed a significant response to therapy in that the bronchus remained free of obstruction after treatment; 1 patient had partial improvement, and 1 patient failed to show significant improvement and expired from the sequelae of persistent airway obstruction.

CONCLUSIONS

Endobronchial brachytherapy can be an effective modality for managing recurrent stenoses caused by hyperplastic granulation tissue at the bronchial anastomosis. The optimal timing and ideal candidate for intraluminal radiation therapy for this problem remains a challenge and warrants further investigation.

Experience with Ultraflex expandable metallic stents in the management of endobronchial pathology

BACKGROUND

Experience with Ultraflex expandable metallic stents (Micro-invasive, Boston Scientific, Watertown, MA) in the management of endobronchial pathologies leading to airway compromise is reported.

METHODS

Between January 1999 and August 2000, twenty-eight expandable metallic stents were inserted into 25 patients (7 men and 18 women; median age, 65 years) who presented with respiratory distress. Each patient had comorbid medical conditions or end-stage malignancy that precluded formal surgical repair. Seventeen patients had intrinsic airway obstruction, 5 had extrinsic compression, 2 had a tracheal tear, and 1 had a tracheoesophageal fistula. Stents were inserted through a bronchoscope under direct vision. Eighteen patients received tracheal stents alone (1 of these patients received two tracheal stents), and 5 patients received bronchial stents only. Two patients received a tracheal and a bronchial stent. Twenty-one stents were covered and seven were uncovered.

RESULTS

All patients had successful stents with restoration of airway patency and closure of tracheal defects. One patient developed a respiratory infection early after the operation. Follow-up bronchoscopy confirmed satisfactory stent position in each patient. Late complications included sputum retention, halitosis, and granulation tissue formation.

CONCLUSIONS

Ultraflex expandable metallic stents should be considered in the management of airway compromise in selected patients for whom formal surgical repair is inappropriate or contraindicated.

Nd-YAG laser damage to metal and silicone endobronchial stents: delineation of margins of safety using an in vitro experimental model

STUDY OBJECTIVE

To identify margins of safety within which bronchoscopic Nd-YAG laser resection can be performed without damaging indwelling tracheobronchial stents.

DESIGN

Experimental in vitro study simulating a patient-care environment.

METHODS

Uncovered and covered metal Wallstent (Schneider; Zurich, Switzerland) and Dumon (Bryan Corporation; Woburn, MA) silicone stents were deployed in the tracheobronchial tree of a ventilated and oxygenated (fraction of inspired oxygen, 40%) heart-lung block of a dead canine. Rigid bronchoscopic Nd-YAG (1,064 nm) laser procedures were performed in order to deliver laser energy using fiber-to-target distances of 10 mm and 20 mm, and noncontact, continuous-mode, 1-s pulses at power settings of 10 W, 30 W, and 40 W. The major outcome measure was laser-induced stent damage, defined as discoloration, ignition, or breakage. This was assessed using six power densities: 75 W/cm(2), 172 W/cm(2), 225 W/cm(2), 300 W/cm(2), 518 W/cm(2), and 690 W/cm(2).

RESULTS

The uncovered Wallstent and the silicone stent remained intact at power densities of 75 W/cm(2) (10 W, 20 mm) and 172 W/cm(2) (10 W, 10 mm), but were damaged at power densities > 225 W/cm(2) (30 W, 20 mm). The covered Wallstent was damaged at all power densities tested.

CONCLUSION

Uncovered Wallstent and silicone stents are not damaged when Nd-YAG laser energy is delivered using power densities < or = 72 W/cm(2) (10 W, 10 mm). Covered Wallstents, however, had a high likelihood of ignition at all power densities studied.

Endobronchial management of advanced lung cancer

BACKGROUND

Patients with lung cancer often have bulky endobronchial disease, endobronchial extension, or airway compression. Many endobronchial treatment modalities are available to supplement traditional therapies for advanced lung cancer.

METHODS

The author reviews the use of several endobronchial treatment modalities that can augment standard antitumor therapies for advanced lung cancer, including rigid and flexible bronchoscopy, laser therapy, endobronchial prosthesis, and photodynamic therapy.

RESULTS

Since the early 1980s, technical advances in interventional techniques have enhanced symptom-free survival and quality of life for patients with lung cancer. Although interventional procedures are not definitive therapies, they often relieve the strangling sensation produced by airway occlusion.

CONCLUSIONS

Endobronchial interventions are important adjuncts in the multimodality management of lung cancer and should become standard considerations in the management of patients with advanced lung cancer. For patients with respiratory symptoms associated with their disease, these interventions provide symptom palliation and improved quality of life.

Endoluminal laser application under percutaneous cardiopulmonary support in severe tracheal stenosis

Laser ablation under bronchoscopic guidance was conducted on 2 patients with severe tracheal stenosis. Case 1 was a 57-year-old man admitted to our emergency unit because asphyxia. Bronchoscopy showed the lumen occluded at the bifurcation by tracheal cancer. Case 2 was a 62-year-old woman who underwent tracheostomy elsewhere for respiratory failure caused by a brain contusion and was treated for 3 months. After transfer to our emergency unit, bronchoscopy showed severe tracheal stenosis. Tracheoplasty conducted under bronchoscopy used a noncontact Nd:YAG laser at an output of 10-40 W and irradiation time of 1 second per shot. Total irradiation energy was 1700-1900 J. Percutaneous cardiopulmonary support was used during the laser procedure due to asphyxia. All procedures were completed satisfactorily and clinical symptoms improved dramatically in both cases. Laser tracheoplasty under bronchoscopic guidance treated severe stenosis safely and completely. Percutaneous cardiopulmonary support was very useful in preventing severe respiratory failure or asphyxia during this procedure.

Long-term safety and tolerance of silicone and self-expandable airway stents: an experimental study

BACKGROUND

A variety of respiratory stents are currently available, but the ideal airway prosthesis seems far from being recognized. The objective of this study was to verify safety and long-term effect on the bronchial wall of three different types of airway stents.

METHODS

Twelve healthy adult sheep were divided in three groups, scheduled to receive: (1) bare self-expandable metallic stents (Gianturco); (2) silicone stents (Dumon); and (3) covered self-expandable synthetic stents (Polyflex). Insertions were performed through a rigid bronchoscope under general anesthesia. Chest roentgenogram was performed 1 and 6 months after surgery, and flexible bronchoscopy after 6 months. Twelve months postoperatively, the animals were killed and a postmortem examination was carried out.

RESULTS

All Polyflex stents migrated during the observation period; one late migration was observed in the Dumon group. Microscopic study showed: (1) Gianturco stents: full-thickness perforation of the bronchial wall covered by a thick layer of a chronic inflammatory infiltrate. Infection by Candida at the bottom of some ulcerations; (2) Dumon stents: mild bronchial inflammation (squamous metaplasia, submucosal inflammatory infiltrates; granuloma-like infiltrates). In case of displacement, no significant changes of the previously stented bronchus occurred; and (3) Polyflex stents: no changes of the previously stented bronchi.

CONCLUSIONS

Gianturco stents proved unsafe in the long term, owing to the risk of severe airway wall damage. The Polyflex stent is well tolerated but presents a high migration rate. Silicone stents show several limitations but appear to be well tolerated by the host mucosa.

Flexible bronchoscopy: a safe method for metal stent implantation in bronchial disease

BACKGROUND

Endoscopic bronchoplastic procedures, such as metal stent implantation, are for safety reasons and mainly performed using rigid bronchoscopy. Major complications, such as bleeding and accidental airway occlusion, are thought to be better managed with the rigid device. An increasing number of pneumologists, however, use the flexible fiberscope for endobronchial stenting.

METHODS

Sixty-five stent implantations were performed in 51 patients with flexible fiberoptic bronchoscopy. We implanted 27 Tantalum Strecker stents (Boston Scientific Co, Watertown, MA), 20 Nitinol Accuflex stents (Boston Scientific Co) and 18 Wallstents (Schneider, Zurich, Switzerland). Underlying conditions were malignant disease in 84% and benign bronchial collapse in 16%. Sites of implantation were the trachea (45%), the main bronchi (35%), and other locations (20%). In 47 cases the patients received intravenous sedation combined with high frequency jet ventilation, and in 18 cases the patients were treated with topical anesthesia alone.

RESULTS

Mean examination time was 58.3 (standard deviation 29.1) minutes. Eighty percent of patients experienced immediate clinical improvement in respiratory symptoms. Spirometric parameters (forced expiratory volume in one second, peak expiratory flow rate, forced vital capacity) increased. Complications included hypertension (17%), hypotension (12%), hypoxia (5%), bronchospasm (4%), initial displacement of the prosthesis (11%), and diameter mismatch between stent and bronchus (5%). All complications were managed safely. Relevant bleeding or asphyxia during the procedure has not been observed. Late stent migration was observed in 12% of cases. There were 3 fatalities within 30 days of stent placement which, however, were not attributed to the implantation technique.

CONCLUSIONS

Flexible fiberoptic bronchoscopy is a safe and suitable method to perform endobronchial metal stent implantation. Complications were rare and not serious. Initial misplacement of the prosthesis occurred in some cases and necessitated removal and replacement within the same procedure.

Pulmonary function improves after expandable metal stent placement for benign airway obstruction

STUDY OBJECTIVE

To determine whether expandable metal stent placement for benign airway lesions improves pulmonary function.

DESIGN

Case series.

SETTING

University medical center.

PATIENTS

Nine patients who underwent balloon-mediated expandable metal stent deployment for airway obstruction due to benign etiologies.

RESULTS

All nine patients had expandable stents deployed for benign airway lesions using fiberoptic bronchoscopy and fluoroscopic guidance. Pulmonary function improved after stent placement. The mean FVC increased by 388 mL (95% confidence interval [CI], 30 to 740 mL), the mean peak expiratory flow (PEF) increased by 1,288 mL (95% CI, 730 to 1,840 mL), the mean FEV1 increased by 550 mL (95% CI, 240 to 860 mL), and the mean forced expiratory flow between 25% and 50% of vital capacity (FEF25-75%) increased by 600 mL (95% CI, 110 to 1,090 mL). Corresponding relative measurements included increases in FVC (12%), PEF (95%), FEV1 (38%), and FEF25-75% (87%). The complete characterization of a benign airway obstruction generally required a multimodal approach.

CONCLUSIONS

Expandable metal stent placement appears to be an effective therapy for benign airway obstruction.

Elastic deformation properties of implanted endobronchial wire stents in benign and malignant bronchial disease: A radiographic in vivo evaluation

PURPOSE

To evaluate the long-term mechanical behavior in vivo of expandable endobronchial wire stents, we imaged three different prostheses in the treatment of tracheobronchial disease.

METHODS

Six patients with bronchial stenoses (three benign, three malignant) underwent insertion of metallic stents. Two self-expandable Wallstents, two balloon-expandable tantalum Strecker stents and two self-expandable nitinol Accuflex stents were used. Measurements of deformation properties were performed during voluntary cough by means of fluoroscopy, at 1 month and 7-10 months after implantation. The procedures were videotaped, their images digitized and the narrowing of stent diameters calculated at intervals of 20 msec.

RESULTS

After stent implantation all patients improved with respect to ventilatory function. Radial stent narrowing during cough reached 53% (Wallstent), 59% (tantalum Strecker stent), and 52% (nitinol Accuflex stent) of the relaxed post-implantation diameter. Stent compression was more marked in benign compared with malignant stenoses. In the long term permanent deformation occurred with the tantalum Strecker stents; the other stents were unchanged.

CONCLUSION

Endobronchial wire stents can be helpful in the treatment of major airway collapse and obstructing bronchial lesions. However, evidence of material fatigue as a possible effect of exposure to recurrent mechanical stress on the flexible mesh tube may limit their long-term use. This seems to be predominantly important in benign bronchial collapse.

Bioabsorbable self-reinforced poly-L-lactide, metallic, and silicone stents in the management of experimental tracheal stenosis

The aim of the present study was to compare, in rabbits, the biocompatibility and suitability of a bioabsorbable spiral stent made of self-reinforced poly-L-lactide (SR-PLLA) in the management of experimental tracheal stenosis with stents made of metal and silicone. Tracheobronchial stenosis, and its management, is still problematic because stenoses are not always amenable to surgical resection and reconstruction, especially concerning anastomotic problems and stenosis after lung transplantation. Stenosis can be handled with stenting, although the ideal stent has yet to be developed; all the stents available have their disadvantages. Because stenting of the airways can be only temporary, stents made of bioabsorbable materials, theoretically, offer benefits. Tracheal stenosis was created in rabbits by the extramucosal resection of cartilaginous arches of the cervical trachea. After a few weeks, the animals were operated on again, and those stenoses that had developed were dilated with a balloon. Stents then were implanted in the area of stenosis to keep the dilated trachea open. All the animals in the group with silicone stents had to be killed because of respiratory difficulties: their stents had a tendency to occlude because of internal encrustation, and they developed a hyperplastic polyp at the ends of the stents. The SR-PLLA and metallic stents were tolerated well, and after follow-up ended the animals were put to death. This experimental study showed that silicone stents had a tendency to occlude and that stents made of metal and of SR-PLLA were well tolerated and can be used in the management of airway stenosis.

Stenting therapy for stenosing airway disease

Stenosing airway disease is classified as intraluminal obstruction, extrinsic compression, and malacia by the anatomical site of the lesion. Stenting therapy is indicated for symptomatic relief of life-threatening dyspnea caused by the last two types. Airway stents are made with metal mesh and/or silicone rubber, and currently more than 20 kinds of stent are available. The metal stent (e.g. Gianturco stent, Wallstent) is easy to insert, may not need general anesthesia, and has wider internal lumen. Because it is very hard to reposition or remove, it is mainly used in malignant airway obstruction. Among many kinds of silicone stent, the Dumon stent is most widely used for benign and malignant airway stenoses, but general anesthesia and rigid bronchoscopy are needed for insertion. It can be removed when the stenosing airway disease subsides completely. In many clinical studies, most patients (85-90%) improved immediately after stenting, and procedure-related mortality is low (< 3%) in experienced centers. Stent displacement, mucus impaction, and granulation tissue formation are potential complications. Stenting is one of many effective therapeutic modalities for stenosing central airway disease. Careful patient selection, experiences, and continuous development of new technology will bring better results.

A Dumon stent inserted for bronchial stenosis causing a left bronchopericardial fistula: report of a case

We present herein the case of a 59-year-old man in whom a Dumon stent, inserted as treatment for stenosis of the left main bronchus, caused a left bronchopericardial fistula. The patient initially presented with severe dyspnea caused by main bronchial stenosis of unknown origin for which a Dumon stent was inserted at a local hospital. The Dumon stent migrated to the endobronchus through the stenosis of the left main bronchus a few days later, and his dyspnea remained unresolved. He was subsequently referred to our department 6 months later, where a left pneumonectomy under supportive cardiopulmonary bypass through the femoral artery and vein was performed, and a postoperative pathological diagnosis of bronchial leiomyosarcoma was made. For this rare group of malignant tumors, early diagnosis permits complete surgical resection of the mass and offers the best prognosis. Excision of the tumor should be performed under cardiopulmonary bypass through the femoral vessels when a risk of sudden rupture of the pulmonary artery or vein exists for any reason.

Airway simulation to guide stent placement for tracheobronchial obstruction in lung cancer

BACKGROUND

To effectively palliate large airway obstruction in advanced unresectable lung cancer (stage IIIB or IV), we developed an airway imaging technique to guide selective endobronchial metallic stent placement.

METHODS

Fourteen consecutive patients with severe dyspnea (American Thoracic Society grade 4) had a combination of fiberoptic bronchoscopy, chest roentgenography, computed tomographic scanning, helical computed tomography with three-dimensional reconstruction, and intraluminal bronchography with selective bronchial guidewire placement under fluoroscopy to visually reconstruct and simulate the abnormal airway before and during stent placement. Wallstent or Gianturco intraluminal stents were used alone or in combination (up to five stents) to establish patency of the distal trachea and the major bronchi.

RESULTS

All 14 patients had successful deployment with initial relief of airway stenosis (>75% predicted diameter). No procedural complications were noted. However, technical problems included stent foreshortening and imprecision of placement, misinterpretation of bronchography (mucous versus tumor), and airway maintenance during manipulation. Length of stay attributable to the procedure averaged 4 days. Stent placement initially improved the dyspnea score in 7 of 14 patients. Five of 14 died in less than 1 month, with the remainder alive at up to 8 months' follow-up. Of those surviving more than 1 month, the Karnofsky score improved in 4 and was unchanged in 5, with 2 dependent (Karnofsky score <50), 3 functional (Karnofsky score, 50 to 70), and 4 active (Karnofsky score >70).

CONCLUSIONS

A protocol combining helical computed tomography with three-dimensional reconstruction, bronchography, and bronchoscopy allows accurate assessment of malignant airway obstruction to facilitate intralumenal stent placement for relief of stenosis. Patient selection to favor effective palliation and cost effectiveness has yet to be defined.

Management of Tracheal Neoplasms

Patients with tracheal involvement from primary or secondary neoplasms usually present with relatively nonspecific symptoms of cough, wheeze, and shortness of breath. Prompt diagnosis often requires a high index of suspicion. Tomography or computed tomography of the chest will often confirm the presence of a tracheal lesion. A detailed rigid bronchoscopic assessment by an experienced thoracic surgeon is essential for establishing the extent of tracheal involvement. Although advanced tumor stage often precludes surgical resection, the application of current operative techniques allows a significant number of tracheal tumors to be completely excised and primarily reconstructed. Adjuvant radiotherapy is often employed with surgical resection to improve local control and enhance the potential for cure.