Use of Gianturco self-expandable stents in the tracheobronchial tree

Treatment of Tuberculous Bronchial Stenosis with Expandable Metallic Stents

Gianturco expandable metallic stents were placed in 5 patients with dyspnea on exercise due to tuberculous bronchial stenosis. The stents were placed after dilatation with a 10-mm diameter high pressure balloon catheter. In all 5 patients, obstructive changes disappeared following the procedure, and dyspnea on exercise improved markedly. No complications related to the procedure were encountered. At follow-up during a period of up to 38 months, 2 patients showed bronchial restenosis at 11 and 17 months, respectively, after stent placement. Restenosis by granulomatous tissue was successfully treated by laser ablation. One patient showed slight one-day hemoptysis 26 months after stent placement.

Placement of Two Types of Spiral Z-Stents at the Bronchial Carina for the Treatment of Terminal Lung Cancer – a New Method

Dumon® Y-stents and Dynamic stents are used to treat carinal stenosis, but their placement severely impairs the expectoration of secretions, making frequent bronchoscopic aspiration necessary. We report here five patients with terminal lung cancer who had stenosis of the lower trachea and main bronchi treated using spiral Z-stents. A long tapered spiral Z-stent was placed in the lower trachea and one main bronchus, and a short straight spiral Z-stent in the contralateral main bronchus. No patients required bronchoscopic aspiration of secretions after stenting. Before stenting, all of the patients were severely dyspnoeic, requiring oxygen and having to sit in the orthopnoeic position. After stenting, the patients' dyspnoea improved, with one patient becoming ambulant without the need for oxygen support. These results suggest that the use of spiral Z-stents in stenosis of the tracheal carina in advanced lung cancer is effective in reducing the need for bronchoscopic aspiration and enhancing quality of life.

The use of self-expandable metallic stents in the airways in the adult population

The airway stents restore patency in the face of luminal compromise from intrinsic and/or extrinsic pathologies. Luminal compromise beyond 50% often leads to debilitating symptoms such as dyspnea. Silicone stents remain the most commonly placed stents worldwide and have been the "gold standard" for the treatment of benign and malignant airway stenoses over the past 20 years. Nevertheless, silicone stents are not the ideal stents in all situations. Metallic stents can serve better in some selected conditions. Unlike silicone stents, there are large and increasing varieties of metallic stents available on the market. The lack of prospective or comparative studies between various types of metallic stents makes the choice difficult and expert-opinion based. International guidelines are sorely lacking in this area.

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.

Examination of expandable metallic stent removed at autopsy

OBJECTIVE

We evaluated the damage to expandable metallic stents (EMS) based upon analysis of EMS removed at autopsy.

METHODOLOGY

Seventeen EMS were obtained during autopsy from the main bronchi of nine patients with lung cancer. Each EMS was categorized into one of the following three groups, according to the degree of EMS damage: no damage at all (ND), damage to part of the EMS (PD), and marked damage (MD) that caused loss of function of the airway stent. The removed EMS were examined using a scanning electron microscope.

RESULTS

Of the 17 stents, ND occurred in 13 (7/9 primary, 6/8 secondary), PD in four (all secondary), and MD in none. None of the stents had completely lost the ability to function as an airway stent. Bacterial biofilm formation (BBF) was detected on EMS from four patients.

CONCLUSIONS

Bacterial biofilm forms on EMS implanted into the airway. Some physical damage was present in four of 17 EMS, but all remained functional.

Tracheobronchial stenting for tuberculous airway stenosis

We reviewed the results of the use of the 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 > 1.8 million. Between February 1994 and September 2001, seven patients with tuberculous tracheobronchial stenosis (mean age, 43 years) 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. There were no deaths. One patient developed a pneumothorax. Two patients experienced migration of the stent, which required reintervention for adjustment of position of the stent. The stents were left in situ for a mean period of 32 months. There was marked improvement in dyspnea in all patients after the procedure, as determined by visual analog scale. Endoscopic dilatation with placement of a silicone stent is an effective treatment for patients with tuberculous tracheobronchial stenosis.

Metallic tracheal stents: complications associated with long-term use in the upper airway

The use of metallic airway stents for the treatment of benign airway stenosis is increasingly advocated; however, the long-term safety and efficacy of these devices has not been established. Three case studies involving late but significant proximal tracheal stent complications are reported: 1 related to proximal mechanical stent failure and 2 related to obstructing granulation tissue and stenosis at the proximal stent orifice. Placement of these stents in close proximity to the cricotracheal junction is thought to be primarily responsible for these complications as a result of the excess shearing forces created at the stent-mucosal interface by the differential motion of the stent relative to the rigid subglottic airway and the more distensible trachea. Although the use of metallic stents remains appropriate in cases in which there is a defined and relatively short-term end point for treatment, caution is urged in using them in the proximal trachea for long-term management of benign airway disease.

Successful surgical management of a tracheopulmonary artery fistula caused by an intratracheal expandable metal stent

We describe a boy who underwent slide tracheoplasty and relocation of the left pulmonary artery at 3 months of age to treat pulmonary artery sling with congenital tracheal stenosis. Persisting tracheal stenosis required that he have a Palmaz stent inserted on postoperative day 77. He developed massive hemoptysis after the fourth attempt to expand the stent balloon and immediate computed tomography showed a tracheopulmonary artery fistula. Using cardiopulmonary bypass, we conducted emergency surgery to successfully manage the fistula. He currently depends on mechanical ventilation.

Endotracheal balloon dilatation and stent implantation in benign stenoses

BACKGROUND

Tracheal reconstruction is the treatment of choice in nontumorous tracheal stenoses, but recurrences and concomitant medical conditions limit this approach. We investigated the outcome after balloon dilatation and silicone stent implantation.

METHODS

Forty-two patients with inoperable tracheal stenoses underwent balloon dilatation and afterward silicone stent implantation. Patients were divided into two groups, in group A 24 patients received tracheal stents as a temporary treatment. In group B, definitive stenting was done in 18 patients with severe concomitant medical conditions that did not allow for stent removal.

RESULTS

Immediate results were satisfactory in all patients. In group A, stents could be removed in 12 patients after a mean interval of 20 months. Restenting was not required during the following 18.9 months. Twelve patients are still waiting for stent removal after a mean follow-up of 20 months. In group B, mean follow-up is now 48.4 months. Complications included retained secretions, dislocation, and granuloma formation.

CONCLUSIONS

Stenting after balloon dilatation is safe and effective in benign tracheal stenoses. After temporary use, stents can be removed when local and general conditions permit. In all other patients, stenting proved beneficial for 5 years as more definitive treatment.

Small intestinal submucosa covered expandable Z stents for treatment of tracheal injury: an experimental pilot study in swine

PURPOSE

To evaluate efficacy of small intestinal submucosa (SIS) as a stent covering in healing experimentally created tracheal defects and to explore the trachea's reaction to placement of SIS-covered stents.

MATERIAL AND METHODS

A tracheal defect with a diameter of approximately 10 mm was created in six swine with use of a blade or electrocauterization. A double-body, self-expandable SIS-covered Gianturco Rösch Z stent was placed into the trachea to cover the defect. The animals were observed, and were killed when they developed respiratory problems. Autopsy and histologic studies were performed.

RESULTS

The SIS-covered stents were accurately placed without immediate complications related to placement. All animals developed respiratory problems on follow-up. One animal died 9 days after procedure because of pneumonia, the others five were killed at 12, 17, 18, 28, and 56 days because of stridor, wheezing, and cough. At autopsy and histology, the tracheal defects were found to be completely healed, with epithelial lining and regeneration of submucosal glands. Animals whose defects were created with a blade demonstrated cartilage remodeling between 9 and 18 days, and apparent deposition of new cartilage at 28 days after SIS placement. The defects made by electrocauterization showed only fibrous tissue with no cartilage regeneration. The tracheal lumen was narrowed by overgrowth of granulation tissue, particularly at the end wires of the stents. In three animals, polypoid masses caused 60%, 70%, and 80% tracheal obstruction, respectively.

CONCLUSION

Placement of SIS-covered stents contributed to rapid and effective healing of large tracheal defects. Rigidity and oversizing of Gianturco Rösch Z stents led to secondary changes of the tracheal wall, causing significant airway obstructions. Smaller size and flexible stents should be selected for future work.

Covered expandable tracheal stents in the management of benign tracheal granulation tissue formation

BACKGROUND

Tracheal obstruction secondary to benign proliferation of granulation tissue is a difficult problem to address if tracheal resection is contraindicated. Some patients may benefit from Nd:YAG (neodymium: yttritium-aluminum garnet) laser fulguration or tracheal stenting. If uncovered expandable metallic stents are employed granulation tissue can regrow and proliferate through the mesh, thereby obstructing the lumen once again. Covered metallic stents confer the advantage of preventing granulation tissue proliferation and therefore maintain patency of the tracheal lumen.

METHODS

Two patients who developed tracheal obstruction secondary to proliferating granulation tissue formation after tracheostomy and who were medically unfit for prolonged general anesthesia were successfully treated using covered expandable metallic tracheal stents.

RESULTS

Each patient demonstrated a significant improvement in respiratory status, and in both patients, at 6 and 9 months' follow-up, stent position has not changed, tracheal lumen remains patent, and there has been no proliferation of granulation tissue through the stent.

CONCLUSIONS

Covered expandable metallic stents should be considered in the management of patients with proliferating tracheal granulation tissue when tracheal resection is contraindicated.

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.

Stenting of the tracheobronchial tree

Endoscopic treatment of endobronchial obstructions is becoming increasingly important. Tracheobronchial stents often are needed in the treatment of obstructions from submucosal or extrabronchial lesions. Tube stents have been available since the early 1960s but are underused because their insertion requires the use of a rigid bronchoscope. With the recent development of metallic stents, interventional radiologists increasingly are involved in the treatment of tracheobronchial obstructions. Metallic stents, easily placed with flexible bronchoscopy, are growing in popularity. All available tracheobronchial stents have been shown in various clinical series to be able to achieve immediate resolution of respiratory symptoms from various tracheobronchial obstructions. A stent's performance, however, should not be based solely on short-term response. Presently, there is no ideal stent because none is free of complications and none are able to consistently maintain life-long patency. Gianturco stents are associated with serious major complications (bronchial perforations and strut fractures) and are no longer recommended for use in the tracheobronchial tree. The Palmaz stent has also fallen into disfavor, because a strong external force, such as a vigorous cough, can recompress it. The Strecker stent can only be used in smaller airways, but may be useful in the accurate stenting of short segment stenoses because it does not foreshorten on deployment. The Wallstent and Ultraflex are our present metallic stents of choice. Both are easy to deploy, available in covered forms, exert adequate radial force, remain relatively stable in position, and have good longitudinal flexibility for use in tortuous airways. Disadvantages include excessive granulation tissue formation and difficulty of removal once the stent has been epithelialized. Metallic stents should be chosen very carefully for use in benign lesions with ongoing active local inflammation or when temporary stenting is needed. In the absence of an ideal stent, technologic advancements will continue. Potential developments include removable metallic stents, biodegradable stents, and chemically and radioactively coated stents. Unquestionably, the expanding stent market will drive scientific research toward the development of the ideal stent. Clearly, physicians need to be ready to assess these technologic advancements.

Tracheobronchial strictures: treatment with a polyurethane-covered retrievable expandable nitinol stent--initial experience

A polyurethane-covered retrievable expandable stent was placed in 13 patients with tracheobronchial strictures. In four patients with benign strictures, the stent was removed with use of a retrieval hook 2-6 months after placement. After stent removal, three of the four patients did not need further treatment. The retrievable stent warrants further investigation in the treatment of tracheobronchial strictures.

Efficacy and complications of the Gianturco-Z tracheobronchial stent for malignant airway stenosis

PURPOSE

To describe our experience using the Gianturco Z-stent (G-Z stent) for the management of malignant tracheobronchial stenosis, with special reference to complications.

METHODS

Thirty-six stents were used in 22 patients with 28 lesions. Thirteen patients were grade 5 according to the Hugh-Jones classification. The technical success rates, follow-up results, and complications were reviewed on the basis of the patients' charts and radiographs.

RESULTS

All stents were successfully placed in the ideal position without procedure-related complications. After the procedure, respiratory status improved in 95% (21/22) of patients, and performance status improved in 77% (17/22). Mean survival after stent placement was 15 weeks. Four patients suffered from increased thick secretions requiring multiple suctioning and aspiration by bronchoscopy. One of these patients died from asphyxiation 2 weeks after placement. Stent disruption and/or migration was observed in six patients. Of these six, four experienced life-threatening hemoptysis; all four had received aggressive anticancer treatment.

CONCLUSION

G-Z stents are useful for palliation of malignant tracheobronchial obstruction. However, complications of stent strut fracture and migration give cause for concern.

Interventional radiology and the use of metal stents in nonvascular clinical practice: a systematic overview

PURPOSE

The intent of this systematic overview was to describe the clinical role of metal stents in nonvascular health care interventions and the level of evidence supporting their use.

MATERIALS AND METHODS

Structured searches of Medline were conducted and limited to original peer-reviewed articles published in English.

RESULTS

Clinical practice involving metal stents was reported in more than 109 clinical series involving 4,753 patients. Stents were placed mainly for palliation of malignant biliary, esophageal, and airway obstruction in patients who were untreatable or had surgically unresectable lesions. Assessment of these interventions has so far centered on safety and technical success. Efficacy, quality of life, and costing factors were not routinely reported. Randomized trial evidence was available but limited; six randomized trials involving metal stents have been reported. Three trials involved biliary malignant obstruction, and all three reported metal stent (132 patients) palliation to be superior to plastic stent palliation (136 patients) based on longer patency and lower reintervention costs. Safety and complication differences between stents, however, were inconsistent across trials. In three trials involving esophageal malignant obstruction, metal stent (82 patients) palliation was reported to be superior to plastic stent (41 patients), based on lower complication and reintervention rates, and superior to laser therapy (18 patients), based on better dysphagia relief.

CONCLUSION

Use of metal stents has been reported for obstructed ducts and passageways of most body systems. There is, however, limited controlled trial evidence confirming the advantages of their use over plastic stents or other forms of treatment.

Tuberculous stenosis of the left main bronchus: results of treatment with balloons and metallic stents

PURPOSE

To assess the results of treatment with balloon dilation and metallic Z stents in patients with tuberculous stenosis of the left main bronchus.

MATERIALS AND METHODS

Nineteen patients with tuberculous stenosis of the left main bronchus were treated with balloon (n = 15) and self-expanding metallic Z stents (n = 4). Respiratory status and pulmonary function tests were followed up for 2-90 months.

RESULTS

In the balloon group, improvements in dyspnea occurred in 73% (11 of 15 patients) immediately, 73% after 1 month, 73% after 6 months, 64% after 1 year, 64% after 3 years, and 42% after 6 years (Kaplan-Meier method). Improvement of pulmonary function (FEV1 or FVC) was achieved in 62% (eight of 13) after 1 year. In the stent group, immediate improvements of dyspnea or pulmonary function occurred in all patients. However, fracture of the stents occurred in two patients, at 4 and 18 months, respectively. Occlusion of the lumen of the stent by granulation tissue occurred in another at 18 months.

CONCLUSION

Balloon dilation can be an effective method for the treatment of tuberculous stenosis of the main bronchus. Metallic Z stents should be used cautiously because of their problems of mechanical durability and overgrowth of granulation tissue.

Endobronchial stenting for extrinsic compression caused by pulsatile pulmonary artery in a 4-week-old infant

Respiratory compromise secondary to external vascular compression may complicate the course of infants and neonates undergoing repair of congeni tal heart disease. Management of such complications usually involves prolonged ventilatory support and even additional high-risk surgical procedures. In recent years, endobronchial placement of self-expanding stents became a realistic treatment option, although there is controversy as to which of the many stents available today give the best results. We report the first successful endobronchial placement of a self-expanding stent in a 4-week-old infant. This conservative treatment for extrinsic airway compression led to the rapid extubation and recovery of the patient.

A novel approach to tracheostomal collapse: the use of an endoluminal Palmaz stent

There are a number of surgical treatments for tracheostomal collapse of the pediatric airway. The techniques include tracheoplasty with costal cartilage graft, the placement of a tracheostomy tube and partial tracheal resection and primary tracheal anastomosis to name a few. Since each child may possess unique medical and social factors in additional to the tracheal pathology, the surgical approach must be individualized. A case history of a 1-year-old Vietnamese child with a tracheostomal collapse is presented. In this case, an endoluminal Palmaz stent was placed endoscopically to support the collapsed tracheal segment for 3 months. After 3 months, the stent was removed, and the child has done well without any airway intervention for 2 years. The indications for this novel approach, the technique of insertion and removal of the stent are the focus of this paper.

Comparison of tissue reactions in the tracheal mucosa surrounding a bioabsorbable and silicone airway stents

BACKGROUND

Treatment of tracheobronchial stenosis is problematic. Conservative methods include stenting the stenotic area, but an ideal stent has not yet been developed. Bioabsorbable airway stents offer benefits; the extraction of the device is unnecessary, and the airway preserves its normal function after stent resorption. The aim of this study was to examine the suitability of self-reinforced poly-L-lactide as a material for an airway stent.

METHODS

A spiral airway stent made of 0.7-mm wire of self-reinforced poly-L-lactide was implanted operatively in 9 rabbits intratracheally; silicone stents served as controls.

RESULTS

Silicone stents had a tendency to become stenosed with encrustation material and to develop a hyperplastic polyp at both ends. Self-reinforced poly-L-lactide stents were well tolerated and caused no foreign body reaction, and they had a tendency to penetrate into the tracheal wall. They had disappeared at the end of the follow-up of 10 months.

CONCLUSIONS

This experimental study showed that bioabsorbable self-reinforced poly-L-lactide is a promising material for an airway stent for treatment of airway stenosis.

Aortobronchial fistula after expandable metal stent insertion for pediatric bronchomalacia

Indications for using expandable metal stents (EMS) for airway disease have expanded considerably during the past decade. Complications have been infrequent but can be potentially life threatening. There are four reported instances of vascular bronchial fistula after Gianturco EMS insertion for managing airway disease in adults. The authors report a case of an aortobronchial fistula in a pediatric patient after Palmaz EMS insertion for treatment of bronchomalacia. A 14-year-old boy with severe scoliosis underwent left mainstem bronchus insertion of two Palmaz stents in tandem for correction of complete bronchial obstruction caused by vascular compression. Three weeks later fatal hemoptysis from an aortobronchial fistula developed. Elective EMS insertion for treatment of airway obstruction secondary to compression by vascular structures should be approached with caution. EMS placement should be reserved for situations in which there is no other reasonable surgical alternative.

Tracheobronchial stenting for the treatment of airway obstruction

PURPOSE

The authors report a 5-year experience of inserting the Palmaz stent into infants and children who had a variety of major airway obstructions.

METHODS

From 1992 to 1997, 30 balloon expandable stents (Palmaz) were inserted in the trachea (n = 18) and bronchi (n = 12) of 16 infants, ages 1 week to 26 months (median, 9 months), suffering from three types of serious airway obstruction. In group 1, 10 stents were placed in eight children for tracheal or bronchomalacia. In group II, 11 stents were inserted in four infants for stricture at the site of surgical repair of stenosis. In group III, nine stents were placed to relieve airway compression from enlarged pulmonary arteries associated with severe congenital heart disease in three children and mediastinal lymphangioma in one. Tracheal stents were 30 mm long and were expanded to 8 to 10 mm at placement. Bronchial stents were 12 to 15 mm long and were expanded to 7 to 9 mm. The nonexpanded stents were placed on an inflatable balloon catheter and were inserted into the desired position in the airway through a bronchoscope or endotracheal tube using x-ray control. They were expanded and fixed in place by inflating the balloon to its rated diameter.

RESULTS

In group I, granulation tissue developed over the stents in five of eight cases. Obstructing granulations were removed by scraping or balloon compression in three and resulted in earlier than the planned removal in two. Stents have now been removed in six of eight cases. Major airway obstruction has not recurred. In group II, stents have been in place in all cases for 13 to 56 months after insertion, but in one child with three stents, two were removed for obstructive granulations 44 months after insertion. All are well. All group III patients could be extubated after stenting, but two with heart disease died after 3 and 12 months of palliation. During the course of follow-up, stents in the bronchi of two had migrated, and an additional stent was required. Autopsy in one showed full-thickness bronchial erosion but no perforation by the stent. A total 11 of 30 stents have been removed bronchoscopically in seven children without complications. Another child referred here for tracheal stent removal after laser resection of granulations died at attempted removal because the stent was "welded" into the tracheal wall by the inflammatory reaction. Manipulation of the stent completely occluded the airway.

CONCLUSIONS

Airway stents can be inserted easily and safely and left in-situ for prolonged periods to relieve major airway obstruction from a variety of causes. Tissue reaction may necessitate bronchoscopic manipulation and early stent removal, and adds to the difficulty of removal.

Dumon silicone stents in obstructive tracheobronchial lesions: the Hong Kong experience

The insertion of intraluminal stents is an effective method of relieving the distressing symptom of asphyxia in patients with obstructive lesions in the trachea and main-stem bronchi. We report our experience in the use of the studded Dumon silicone stent (Endoxane prosthesis; Axion, Aubagne, France). Between February 1994 and August 1996, 42 stents were placed in 30 patients. Of the 27 patients with a malignant stricture, 10 had carcinoma of the bronchus, 13 carcinoma of the esophagus, and 4 metastatic carcinoma involving the tracheobronchial tree. The benign lesions were made up of two tuberculous strictures and one suprastomal stenosis after tracheostomy. Stents were placed through a rigid bronchoscope with patients under general anesthesia. Postplacement assessment was performed with a 10-point, symptom-based visual analog scale. In eight less urgent cases, forced expiratory volume in 1 second and forced vital capacity were determined before and after surgery. The mean symptomatic improvement on the 10-point scale was 6.1 points, whereas the forced expiratory volume in 1 second (in the eight patients tested) improved by 75%, and the forced vital capacity improved by 54%. The median survival was 2 months for patients with carcinoma of the bronchus and 3 months for patients with carcinoma of the esophagus. Two patients with metastatic carcinoma and all of the patients with the benign lesions were alive and well after 12 months of follow-up. Insertion of the Dumon stent is a simple, safe, and effective method of countering the distressing symptoms arising from obstructive tracheobronchial lesions.

Transbronchial Palmaz stent placement for tracheo-bronchial stenosis

PURPOSE

Evaluation of the efficacy of transbronchial Palmaz stent placement in the treatment of tracheo-bronchial narrowing.

MATERIALS AND METHODS

Twelve patients with stenoses of the tracheo-bronchial tree were treated with balloon-expandable Palmaz stents. Etiology was anastomotic stenosis after lung transplantation (n = 3), bronchogenic carcinoma (n = 2), external compression from thoracic aortic aneurysm (n = 2), Mycobacterium tuberculosis (n = 1), esophageal carcinoma (n = 1), after lobectomy (n = 1), after lobectomy and endobronchial radiation (n = 1), and lye ingestion (n = 1). All patients had respiratory symptoms, radiologic findings of persistent atelectasis, or worsening pulmonary function tests. Bronchoscopy was used to delineate the stenosis prior to intervention. With use of fluoroscopic guidance, stents were placed in the mainstem bronchus (n = 11), lower lobe bronchus (n = 5), bronchus intermedius (n = 5), trachea (n = 3), and middle lobe bronchus (n = 1).

RESULTS

Initial technical success was achieved in all patients. Ten of the 12 patients (83%) had improvement of clinical pulmonary signs or symptoms. During follow-up, five patients died. One was lost to follow-up and was presumed dead. The 30-day mortality rate was 17% (two of 12 patients). The two complications were superficial laceration of the bronchial mucosa during balloon dilation in one patient and compression of stents by a thoracic aortic aneurysm in another patient.

CONCLUSION

Initial results suggest that transbronchial Palmaz stent placement is a feasible and effective method of treating tracheo-bronchial stenosis.

Tracheal stenosis treated with self-expanding nitinol stent

A self-expanding nitinol stent was used in 2 patients with inoperable tracheal stenosis due to invasive malignant tumor of the trachea. One was a 70-year-old man with recurrent tumor from adenocarcinoma of the left lung, and the other was a 63-year-old man with recurrent tumor in mediastinal lymph nodes from esophageal cancer. The self-expanding nitinol stent is very useful and effective in inoperable tracheal stenosis due to intraluminal tumor invasion.

Migration of Gianturco expandable metallic stents in the upper trachea

Endotracheal expandable metallic stents have been shown to be useful in treating malignant tracheobronchial stenosis. We report two cases of early stent migration in the upper trachea after what appeared to be a successful stent placement. We conclude that care should be taken when placing Gianturco stents across short, extrinsic, stenotic lesions with smooth mucosa located in the upper trachea because they have a tendency to migrate.

Kyphoscoliosis and bronchial torsion

STUDY OBJECTIVE

Severe idiopathic scoliosis is associated with respiratory failure. This usually is secondary to restrictive airway disease and reduced vital capacity. Patients may also suffer from an increase in airway resistance when severe kyphoscoliosis is present.

SETTING

Three patients (two of whom required assisted ventilation) with varying degrees of kyphoscoliosis presented with moderate to severe breathing difficulties.

INTERVENTION

Bronchoscopic examination of these patients showed evidence of torsion with secondary obstruction of the central airways.

RESULTS

The airway obstruction was notable for its slit-like appearance, for the normality of the mucosa at the site of the obstruction, for the relative ease through which an instrument could traverse the obstruction, and once the retained secretions had been cleared, for the preservation of normal anatomy of the distal airways. The insertion of metal prostheses to stent the areas of obstruction prompted an impressive improvement in respiratory status, radiologic findings, and spirometric criteria in each case. Improvement has been maintained over a maximum follow-up period of 4 years.

CONCLUSION

Severe kyphoscoliosis can lead to bronchial torsion and obstruction of the central airways. Patients should be assessed by bronchoscopy to exclude this deformity or any other cause of obstruction. The use of a metal endobronchial stent has been effective in both the immediate and long-term period.

Temporary tracheobronchial stenting in malignant stenoses

Endobronchial stent implantation has been successfully employed in malignant stenoses. The aim of this prospective study was to investigate the temporary use of tracheobronchial stents combined with tumour-specific therapy. All patients received stents for primary palliation of dyspnoea followed by radio- or chemotherapy with the aim of stent removal after reduction of the stenosis. In 22 patients suffering from severe malignant strictures, 34 endobronchial stents (29 Strecker-, 3 Dumon-, 1 Orlowski-, 1 Dynamic-Y-stents) were implanted (in 9 patients, 2 stents were necessary). Patients were treated by irradiation (n = 18) or chemotherapy (n = 4) after stent implantation. Significant improvement of dyspnoea (P < 0.001) and partial oxygen pressure (P < 0.01) was observed. In 11 out of 22 cases (50%), the stents could be removed after successful tumour-specific therapy which led to reduction of stenosis after a mean interval of 31.7 (6-104) days (temporary stenting). During the period of tumour-specific therapy, 9 patients died after a mean interval of 132 (13-347) days (definite stenting). In two cases, stents had to be removed after stent compression, stent dislocation and severe cough. The results suggest that temporary stenting, characterised by subsequent successful tumour-specific therapy, is a new valuable therapeutic strategy. It can "bridge the gap" before tumour-specific therapy can take effect. If tumour-specific therapy is ineffective, definite stenting is the palliative method of choice in severe dyspnoea in bronchial carcinoma.

Partially covered Gianturco stent for tracheobronchial stricture caused by intraluminal tumor

Partially covered Gianturco stents were used successfully in two patients to treat tracheobronchial strictures caused by intraluminal tumor growth. The stents were accurately placed without complications. The covered portion of the stent compressed the tumor, and prevented tumor ingrowth until the patients' deaths. This stent seems to act as effective palliation for tracheobronchial stricture caused by intraluminal tumor.

A shape memory airway stent for tracheobronchomalacia in children: an experimental and clinical study

The authors have designed a coil airway stent using a thermal shape-memory titanium-nickel alloy (SMA) to relieve airway collapse in children. A characteristic of alloy allowed the stent to be enclosed in the thin introducer tube and to position it bronchoscopically in the collapsed airway. When the stent is warmed to 37 to 40 degrees C, it expands to the memorized diameter and stents the airway. In eight rabbits, an experimental model of potentially fatal tracheomalacia was created by fracturing the tracheal cartilages. The stents of 6 mm in diameter and 15 mm in length were placed, and then the stents were recovered to their original shape within 1 minute. All rabbits except one showed no respiratory symptoms during the follow-up period. Results of bronchoscopy performed 6 and 10 months after implantation showed satisfactory patency of the trachea. The rabbits were killed for histological evaluation 6 to 28 months after implantation. The specimens showed little proliferation of granulation and no dislodgement of the stents. This procedure was attempted in two children who had severe bronchomalacia. One 5-year-old patient underwent implantation with a stent of 5 mm in diameter and 25 mm in length into the left main bronchus. The patient was relieved from apneic attacks. The stent was removed 2 years after implantation after a remarkable improvement of ventilation. The other patient with left bronchomalacia, age 1 year 2 months, underwent implantation with a 5-mm x 20-mm stent. The animal experiment and clinical experience indicated that (1) this stent can be easily inserted and removed bronchoscopically, (2) the stent has good tissue compatibility and little interference of mucociliary function, and (3) the SMA stent is a promising therapeutic adjunct in the management of children with severe tracheobronchomalacia.

Endoscopic treatment of malignant airway obstructions in 2,008 patients

We report our 13-year experience with endoscopic treatment of malignant obstructions of the airway by Nd:YAG laser, stents, and intraluminal brachytherapy in 2,008 patients. We performed 2,610 laser resections in 1,838 patients, 66 high dose rate brachytherapies, and we placed 393 tracheobronchial silicone stents in 306 patients. We used the rigid bronchoscope in 96% of the laser procedures and in all cases requiring stent placement; general anesthesia was given to 90% of these patients. Endobronchial radiotherapy was performed under local, anesthesia. In 93% of patients undergoing laser resection, we obtained an immediate patency of the airway with consequent improvement of quality of life. The median time between the first and second laser treatment was 102 days, being longer in the case of stent placement (when required) or in association with brachytherapy. Even if endoscopic treatment should be considered only for palliation, laser vaporization could be curative in case of in situ carcinoma. Since 1983, we have treated 23 such lesions in 17 patients and up to now, none has recurred. Finally, endoscopic resection may allow a better assessment of the true extent of the tumor, shifting to surgery patients originally considered to have inoperable disease or allowing lung-sparing operations (21 and 18 patients of our series, respectively). The total mortality rate was 0.4% (12 patients over 2,798 treatments; 2,710 Nd:YAG laser + 151 stents without laser + 37 brachytherapies without laser) in the first week after the procedures, and was mainly related to cardiovascular problems and respiratory failure. In conclusion, endoscopic resection of lung malignancies is rapid, effective, repeatable, and complementary to other treatments; although it should be considered only palliative, laser resection could be curative in patients with in situ carcinomas and early cancers. Laser, stents, and endoluminal brachytherapy should be available in all centers with major experience; a well-trained team is mandatory to plan the most appropriate treatment and manage any possible complication.

The use of the covered Wallstent for the palliative treatment of inoperable tracheobronchial cancers. A prospective, multicenter study

STUDY OBJECTIVE

To investigate the safety, efficacy, and tolerance of the covered Wallstent for the palliative treatment of inoperable tracheobronchial cancer.

DESIGN

An 8-month prospective study employing either a rigid bronchoscope or a flexible delivery system for prosthesis insertion.

SETTING

Multicentric setting involving four teaching hospitals in Switzerland and Germany.

PATIENTS

Forty patients (29 men, 11 women), average age of 62 years, presenting with an inoperable tracheobronchial cancer.

INTERVENTIONS

After partial airway recanalization with an Nd-YAG laser, the covered Wallstent was inserted 23 times using a rigid bronchoscope (Rigidstep device), and 27 times using a flexible delivery system (Telestep device) under fluoroscopic and endoscopic visualization.

RESULTS

Clinical and endoscopic examination at 1, 30, and 90 days showed improvement in the bronchial lumen and in the dyspnea index. No serious complication (death, perforation, hemorrhage, inability to remove an improperly placed prosthesis) was observed during surgery. Late complications included migration (12%), inflammatory granulations or tumor regrowth at the tip of the prosthesis (36%), and symptomatic retention of secretion (38%).

CONCLUSIONS

Compared with other tracheobronchial prostheses, notably the Dumon stent, the covered Wallstent presents the following advantages: insertion with visual guidance, treatment of extrinsic compressions and esophagobronchial fistulas, and little chance of migration when the prosthesis diameter is chosen correctly. The following disadvantages can be noted: high price; both repositioning and extraction of the released stent are more difficult, though certainly possible; and risk of granulations at the tips of the prosthesis and retention of secretions. Suggestions are made for potential improvements to the stent and insertion system that may result in a significant decrease in early and late complications.

Expandable metallic stents for tracheobronchial stenoses in esophageal cancer

BACKGROUND

Tracheobronchial stenosis in patients with esophageal cancer can be life threatening. Few reports have discussed use of expandable metallic stents for central airway stenoses in patients with esophageal cancer.

METHODS

Twelve patients with esophageal cancer underwent placement of expandable metallic stents for respiratory distress caused by tracheobronchial stricture. Single or double metallic stents were placed in the stenotic airways under fluoroscopic guidance. Improvement in respiratory symptoms and clinical outcome were assessed.

RESULTS

Most stenoses were located in the trachea or the left main bronchus. From one to four expandable metallic stents were placed in each stricture site, with immediate relief of respiratory symptoms in 8 patients. One patient with tracheomalacia in alive 3 years after stent placement and another is alive 6 months after stent insertion. The other 10 patients lived from 10 to 70 days (mean; survival, 35 days) after stent placement. Death was due to progression of disease.

CONCLUSIONS

Although metallic stents are useful for relieving respiratory distress in patients with advanced esophageal cancer, additional therapies should be considered.

Nonvascular stents

Stents or endoprostheses have evolved since their introduction. Initially used only in the vascular system, the use of stents has expanded to use in the biliary, urinary, and gastrointestinal tracts and in the tracheo-bronchial tree. Current use of stents includes treatment of both benign and malignant conditions, with the greatest impact in the palliation of malignant strictures. The biomechanics and types of stents used in each region is reviewed. The indications, insertion techniques, results, and complications of stents in each of the aforementioned regions are also reviewed.

Management of malignant tracheobronchial stenosis with metal stents and Dumon stents

BACKGROUND

Tracheobronchial stenosis caused by malignancy is a life- threatening problem. Stenting is one of the treatment modalities and recently has been used widely for the management of such stenosis, but we do not have a clear guide as to which stent should be selected.

METHODS

We evaluated 25 patients (19 men, 6 women; mean age, 60.7 years; range, 34 to 77 years) received 24 metal stents (four covered with silicone rubber) and three Dumon stents. All 25 patients had severe dyspnea because of airway stenosis caused by malignant tumors.

RESULTS

Among the 25 patients, airway obstruction due to extrinsic compression by tumor developed in 11 and was treated with a bare metal stent. The airway remained patent in 10 patients. In 16 patients with intraluminal tumor invasion, nine lesions were treated with a bare metal stent, four lesions with a covered metal stent, and the remaining three lesions with a Dumon stent. Recurrent stenosis did not occur in any patient with a covered metal stent or a Dumon stent. However, restenosis occurred in 4 patients with a bare metal stent, all of whom received laser therapy. In all patients, stenting immediately relieved dyspnea. Six patients lived for 32 days to 53 months after stenting, and 19 patients died of primary malignancies with a mean survival of 131.9 days.

CONCLUSIONS

Metal stents are effective in treating malignant extrinsic tracheobronchial compression. The use of covered metal stents or Dumon stents is preferable for intraluminal stenosis due to malignant growth.

Metallic endoprostheses for malignant tracheobronchial obstruction: initial experience

PURPOSE

To assess the efficacy of the Wallstent endoprosthesis in malignant tracheobronchial obstruction.

METHODS

Seven patients with irresectable carcinoma of the bronchus were treated with nine Wallstent endoprostheses. The procedures were performed under endoscopic and fluoroscopic guidance. Wallstent endoprostheses ranging from 8-16 mm in diameter and 26-49 mm in length were deployed after balloon dilatation of the strictures.

RESULTS

All stents were successfully deployed in the desired positions. There was one procedural complication and one procedure related death. Three patients showed significant improvement in respiratory status after stenting. At a mean follow-up of 5.1 months, there has been no stent migration, fracture, or collapse. One patient had proximal tumor overgrowth that was treated with additional stent insertion. One patient died after a bout of massive hemoptysis 3 months poststenting and it was difficult to tell whether this was related to the endoprosthesis.

CONCLUSION

The use of the Wallstent endoprosthesis in malignant tracheobronchial obstruction is technically feasible.

Endoscopic management of acute respiratory failure related to tracheobronchial malignancies

Endobronchial treatment has an expanding role in the treatment of tracheobronchial tumors. Most patients are treated in this way for the palliation of dyspnea caused by a tumor located in a major airway. In cases where immediate relief is required, prompt control is better achieved by the neodymium-YAG laser or by stents. These two modalities and their indications and limitations in the endoscopic management of acute respiratory failure related to tracheobronchial malignancies are discussed.

Gianturco-Rösch Z stents in tracheobronchial stenoses

PURPOSE

To evaluate expandable metallic Gianturco-Rösch Z (GRZ) stents for treatment of benign and malignant tracheobronchial stenoses.

PATIENTS AND METHODS

Six patients, ages 45-73 years, were treated for severe dyspnea with placement of GRZ stents. Three patients had benign tracheal lesions (one tracheomalacia, two postoperative) and received uncovered GRZ stents. Three patients had malignant stenoses at the level of the carina; one received an uncovered stent and the other two received silicone-covered GRZ stents.

RESULTS

Two patients with benign lesions responded well to stent placement. One was asymptomatic for a year and then was lost to follow-up; the other improved substantially but died of end-stage lung disease 5 months after stent placement. A third patient with a benign high tracheal lesion did poorly; symptoms recurred secondary to inferior migration of a stent, which was removed surgically at 4 months. All patients with malignant lesions improved symptomatically after stent placement and remained without significant dyspnea until death (from 1 to 6 months).

CONCLUSION

Expandable GRZ stents are promising devices for treatment of benign lesions and offer effective palliation of malignant tracheobronchial stenoses.

Experimental models of tracheobronchial stenoses: a useful tool for evaluating airway stents

BACKGROUND

Stent implantation is a conservative alternative to open operation for treating benign tracheobronchial strictures. Most of the presently available stents were primarily designed for endovascular use. Their respiratory use entails a risk of iatrogenic complications. From a scientific and from an ethical point of view these risks justify preclinical evaluation of new respiratory stents in experimental models of central airway stenoses. Therefore, an attempt was made to develop such models in piglets and adult minipigs.

METHODS

Tracheal stenoses were obtained by creating first a segmental tracheomalacia through extramucosal resection of cartilaginous arches. The fibrous component of the stenoses was then obtained through bronchoscopic application of a caustic agent causing progressive deep mucosal and submucosal injury. Stenoses of the main bronchi were created by topical application of the caustic agent only.

RESULTS

These models demonstrated the typical features of benign fibromalacic tracheobronchial stenoses with constant recurrence after mechanical dilation. Preliminary experiments showed that short-term problems of tolerance of stent prototypes are easily demonstrable in these models.

CONCLUSIONS

These experimental models, which simulate quite realistically human diseases, offer the opportunity to perfect new tracheobronchial stents specifically designed for respiratory use and to evaluate their long-term tolerance before their use in humans.

The use of expandable metallic airway stents for tracheobronchial obstruction in children

Expandable metallic angioplasty stents (Palmaz stent) have been implanted in the trachea and/or bronchi of seven children. Three children had severe tracheal stenosis after tracheoplasty for congenital tracheal stenosis repair, and four had tracheomalacia or bronchomalacia with or without vascular compression. The mean age at stenting was 9.7 months (range, 2 to 15 months). Balloon expandable stents were inserted into the trachea or bronchus through a 3.5-mm bronchoscope under fluoroscopic control. Initially a single tracheal stent was used for all patients except for one with obstruction in the trachea and both bronchi, in whom three stents were implanted. Three children had recurrent airway obstruction 1 month later; one was cured with a second stent; one child died 1 year later; and the other is being treated for heart disease. The others have no serious respiratory problems. The stents in all have been in place for 1 to 25 (mean, 11) months. No immediate complications were noted. Early and late bronchoscopy showed incomplete epithelialization of the stent and patches of granulation tissue on it. Two stents were removed bronchoscopically, one at the completion of treatment for tracheomalacia and the other at the time of recurrent airway obstruction. This preliminary experience indicates that expandable metallic stents have a useful role in the treatment of selected lower airway obstructions.

The expandable metal stent for tracheal obstruction

A 10 month old boy with stridor persisting from birth was found to have tracheal narrowing secondary to myofibromatosis of the tracheal wall. An expandable metal stent was positioned across the tracheal stenosis with immediate clinical improvement. There were no complications relating to stent insertion. The child remained clinically asymptomatic and repeat bronchoscopy at nine months' follow up showed that the stent had become completely endothelialised with no evidence of granuloma formation.