Download - Complications of tracheobronchial airway stents

Complications of tracheobronchial airway stentsSCOTT A. ZAKALUZNY, LT, USAF, MC, J. DAVID LANE, MAJ, MC, USA, and ERIC A. MAIR, COL(SEL), USAF, MC,* Washington, DC

OBJECTIVE: Our goal was to identify and analyzeairway stent complications and to devise ap-proaches to manage stent complications.STUDY DESIGN AND SETTING: We conducted a ret-rospective review of patients from a tertiary medi-cal center.METHODS: Twenty-eight airway stents were placedin 23 patients for benign (n � 15) and malignant (n� 13) tracheobronchial diseases. All patients werefollowed clinically for signs of complications.RESULTS: Nine complications (8 in those with benigndisease and 1 in a patient with malignant disease)were identified and included stent migration (n �

3), excessive granulation tissue (n � 2), stent frac-ture (n � 1), poor patient tolerance (n � 2), andinability to place (n � 1). Avoidance and manage-ment strategies for stent complications are intro-duced.CONCLUSION: Tracheobronchial stents provideminimally invasive therapy for significant airwayobstruction. Stent complications are more fre-quently encountered in the long-term treatment ofbenign conditions. Stents can be successfully re-moved endoscopically if complications arise, butthe longer a metallic stent is in place, the moredifficult it is to remove.SIGNIFICANCE: As airway stent use increases,proper management will be required to avoid andmanage complications. This is the first report to fo-

cus on stent complications and their management.(Otolaryngol Head Neck Surg 2003;128:478-88.)

A irway stents are like new and unique toys thatcapture the eye of those that see them. Similar toa colorful pair of finger-cuffs, which instantlycapture the imagination and ensnare the fingers,airway stents are small, intricate devices that areelegant in their simplicity but have potential forunforeseen complications.

Airway stents have gained increasing popularityin the management of challenging tracheobron-chial obstruction based on the simplicity of theirplacement and the lack of good alternative ap-proaches. As their use has increased, the literaturehas flourished with the use of these intriguingdevices in a variety of clinical settings. Althoughcareful and judicious stent placement has providedsignificant and life-saving airway improvement inmany patients, there are notable potential compli-cations. This is the first article that deals specifi-cally with the complications of airway stents withan emphasis on how to avoid complications aswell as what options are available to manage thesecomplications when they do occur. We outline ourstent complications and highlight important les-sons in the management of airways with stents.

MATERIALS AND METHODSFrom October 1997 to May 2000, 23 patients

(age range, 6 months to 79 years, mean age, 48years) underwent endoscopic placement of a totalof 28 airway stents by the Multidisciplinary Air-way Stent Team (MAST) under the leadership ofthe Otolaryngology Service (E.A.M.) at WalterReed Army Medical Center.1 Detailed patient con-sent was obtained in all cases. Stents were used inboth benign (n � 15) and malignant (n � 13)tracheobronchial diseases. Stents were placed inthe operating room under general anesthesiathrough the use of rigid bronchoscopy combinedwith flexible bronchoscopy and fluoroscopy asneeded. The use of a stent was either the solemanagement or used in combination with adjuvanttreatment such as radiotherapy, brachytherapy,

From Otolaryngology Service (Drs Zakaluzny and Mair) andInterventional Radiology Service (Dr Lane), Walter Reed

Army Medical Center.Presented at the Annual Meeting of the American Academy

of Otolaryngology–Head and Neck Surgery, Washington,DC, September 24-27, 2000.

The opinions or assertions of the authors contained herein arethe private views of the authors and are not to be construedas official or as reflecting the views of the Air Force orDepartment of Defense.

Reprint requests: Eric A. Mair, MD, FAAP, LtCol, USAF,MC, Department of Otolaryngology, Wilford Hall MedicalCenter, 2200 Bergquist Dr, Suite 1, San Antonio, TX78236; e-mail, [email protected].

*Dr Mair is currently at the Department of Otolaryngology,Wilford Hall USAF Medical Center, San Antonio, Texas

Copyright © 2003 by the American Academy of Otolaryn-gology–Head and Neck Surgery Foundation, Inc.

0194-5998/2003/$30.00 � 0doi:10.1016/mhn.2003.107

478

chemotherapy, laser ablation, photodynamic ther-apy, balloon dilatation, or cryotherapy. The stentsused were some of the most commonly used stentson the market today, including Palmaz (Cordis,Johnson & Johnson, Warren, NJ), a stainless steelballoon-expandable stent; Ultraflex (Boston Sci-entific, Natick, MA), a self-expanding metal stentwith a tight weave composed entirely of 1 strandof nickel-titanium; Wallstent (Boston Scientific), aself-expanding stainless steel stent that is flexibleand has small interspaces; Dynamic Y (Rusch AG,Kernan, Germany), a plastic stent in the shape ofa Y with metal struts supporting the anterior por-tion (similar to the trachea); and Dumon (BryanCorporation, Woburn, MA), a plastic tube stentwith numerous studs along the outer surface de-signed to prevent migration. Migration resistance,granulation induction, stent structural integrity,patient tolerance, and ease of placement and re-moval were evaluated. Complications were ana-lyzed based on stent type (metallic versus plastic)and disease type (benign versus malignant). Basedon these clinical experiences, strategies of compli-cation avoidance and management are presented.

RESULTSNine complications are reported (Table 1). The

majority (8 of 9) were associated with underlyingbenign airway pathology and included stent mi-gration (Dumon in proximal stenotic trachea andUltraflex in malacic right main bronchus), stentbreakage (Ultraflex in malacic trachea), excessivegranulation (Palmaz in malacic left main bronchusand Ultraflex in stenotic left main bronchus), poorpatient tolerance due to persistent dysphagia andchest pain (Rusch “Y” in malacic tracheobronchialtree and Ultraflex in subglottis), and technicalinability to optimally seat stent (Rusch “Y” instenotic trachea in a patient with mediastinal fi-brosis). Only 1 complication was associated withmalignant disease (migration of Wallstent in tu-mor-laden right main bronchus). Stents were en-doscopically removed in 7 of 9 complications,whereas the remaining 2 required endoscopic stentmanipulation. Endoscopic stent removal was dif-ficult with metal stents because they became epi-thelialized in the airway within 1 month of place-ment. Overall, plastic stents were easier to remove

Table 1. Summarization of complications and management

AgeBenign ormalignant Diagnosis

Type ofstent Complication

Management ofcomplication

65 y Benign Tracheal stenosis (cervicaltrachea)

Dumon Migration Stent removal and placementof Ultraflex stent

70 y Malignant Malignancy (right mainbronchus)

Wallstent Migration Stent removed and place-ment of covered Ultraflexstent

17 y Benign Severe tracheobronchialmalacia

Rush Y Intolerance Stent removal and placementof Ultraflex stents in tra-chea and main bronchi

Ultraflex Migration Stent removalUltraflex Broken Stent removal

6 m Benign Severe left mainstembronchomalacia withTAPVR

Palmaz Granulation anddeath

Emergent bronchoscopy (un-successful manipulation)

51 y Benign Tracheal stenosis (sub-glottis and cervical tra-chea)

Ultraflex Dysphagia/in-tolerance

Stent removal and tracheot-omy

27 y Benign Wegener’s granulomatosis(left mainstem stenosis)

Ultraflex Granulation Stent manipulation, mitomy-cin-C, laster, balloon dila-tation PDT*

46 y Benign Mediastinal fibrosis (ste-nosis of mid and distaltrachea)

Rusch Y Inability toplace

Stent removal

TAPVR, total anomalous pulmonary venous return; *PDT, photodynamic therapy.

Otolaryngology–Head and Neck SurgeryVolume 128 Number 4 ZAKALUZNY et al 479

but were associated with more migration. Therewas 1 death associated with stent therapy (venti-lation failure due to granulation occluding thelumen after associated laser treatment and pulmo-nary artery bleed at an outside institution).

DISCUSSIONStents have gained increasing popularity in the

management of difficult tracheobronchial obstruc-tion in pediatric and adult airways. In parallel withtheir increased use, complications are being en-countered more frequently. This is the first articlethat focuses specifically on the complications ofairway stents, discussing common complications,preventing complications, providing adjuvanttherapy for stent placement, and dealing with com-plications when they occur.

The ideal stent (1) is easy to insert and remove,(2) has expansion force adequate to maintain air-way patency against compressive forces withoutcausing pressure to the mucosa that could damagethe airway, (3) is available in different sizes toaccommodate various airway sizes and obstruc-tions, (4) maintains its placement in the airwaywithout migration, (5) is made of inert materialthat does not irritate the airway, precipitate infec-tion, or promote granulation tissue, (6) does notobstruct airway tributaries, and (7) does not inhibitmucociliary action and the clearance of secre-tions.2-5 Unfortunately, there is no one ideal stentpresently available for all cases.

Stents are generally divided into 2 groups: thosemade of plastic (eg, silicone) and those made ofvarious types of metals (eg, stainless steel andnickel-titanium). The available metallic stents arefurther broadly subdivided into balloon-expand-able stents and self-expanding stents with pre-defined maximum diameter. Likewise, the indica-tions for use are divided into 2 categories:malignant and benign conditions. Each stent de-sign has its own advantages and disadvantages,which contribute to its efficacy and complicationrate.

There are several potential complications thatcan occur when an airway stent is used. The mostcommon complications are migration of the stent,granulation tissue formation around the stent,problems with mucociliary clearance, poor patienttolerance, problems with placement and removal,

and breakage of the stent. We address each ofthese complications.

MigrationThe inherent need for a stent dictates the im-

portance of it remaining stationary after place-ment. However, migration is one of the most com-mon complications associated with the use ofstents4,6,7 (Fig 1). Plastic stents are more likely tomigrate than are their metal counterparts and mayeven be expelled.5,8 The reason that plastic stentsmigrate more than metal stents lies in the inherentproperties of the stents and how they are deployed.Metal stents are generally placed while in a col-lapsed position and may be expanded with a bal-loon so that they become as close to a custom fit asis possible. In comparison, the plastic stents areusually folded and released in place to expand totheir preformed shape. Therefore, the metal stentis firmly seated and the plastic stent is only as wellpositioned as its predetermined diameter andlength allow. In our cohort, we had 3 stents thatmigrated: 2 metal and 1 plastic. One of the metalstents that migrated was the only complication inour cohort that occurred in a malignant condition.In this case, progressive tumor growth contributedto stent migration. The other metal stent that mi-grated was a short Ultraflex in the proximal rightmain bronchus of a patient with severe tracheo-bronchomalacia who had Ultraflex stents placed inthe trachea as well as the first part of both the leftand right main bronchi. The patient literallycoughed up the right main bronchus stent imme-diately after awakening from stent placement.There have been similar reports of patients whocoughed up stents.7 Contributing factors are thedynamic size of the airway in bronchomalaciaespecially with coughing, the self-expanding na-ture of and short length of the stent, and thelocation at the origin of the right main bronchuswith overlap with the larger trachea. The reasonthat this stent was so easily expelled, actuallybefore the patient even left the operating room, isbecause the metal stent was placed in a very shortsegment between the start of the right main bron-chus and the origin of the right upper lobe. Thismight be compared with taking a small springfrom a ballpoint pen and manipulating it betweenyour fingers. This case highlights the importance

Otolaryngology–Head and Neck Surgery

480 ZAKALUZNY et al April 2003

Fig 1. (A) Plastic Dumon stent distal migration 2 months after placement after laser therapy for tracheal stenosis. Thepatient presented with acute stridor after the stent had migrated distal to the stenosis. The stent was easily endoscopicallyremoved and replaced with an Ultraflex stent. There are no problems 3 years after stent replacement. (B) Metal Wallstentproximal migration 6 weeks after placement after right main bronchus tumor debulking. The stent partially migrated intothe trachea after further tumor growth. The stent was removed endoscopically, with difficulty, in multiple pieces andreplaced with a covered Ultraflex stent. The new stent covering protected the airway from tumor ingrowth.


of selecting the correct stent for each clinical sce-nario/situation. We find less migration with longermetallic stents compared with plastic stents orshort metallic stents.

GranulationThe formation of granulation tissue is a com-

mon complication. It is more likely to form at theproximal and distal ends of the stent, and exces-sive granulation tissue can lead to obstruction ofthe airway.4-6 Granulation tissue formation can bemild enough to remain asymptomatic, moderate soas to produce stridor, or even severe enough tolead to life-threatening respiratory distress6 (Fig2). High-grade narrowing or obstruction often re-quires bronchoscopy to either remove the granu-lation tissue or in some cases the stent.2,6,9 Bron-choscopy is an excellent method for evaluatingpatients with stents both for routine follow-up andwhen they present with symptoms suggestive ofpossible complications. Complications from gran-ulation tissue are more common with metallicstents than with plastic stents.3 Similar to migra-

tion, the reason for greater formation of granula-tion tissue is somewhat inherent to the propertiesof the stent. Metal stents are more rigid, thereforecausing more irritation. Unlike plastic stents,which have only edges at the open ends, metalstents have multiple edges. Those metal edgesplace circumferential pressure on the tissue andlead to the airway irritation and subsequent for-mation of granulation tissue. In addition to causingobstruction of the airway, granulation tissue canbecome a culture medium for bacteria; cultures ofgranulation tissue have been shown to grow nu-merous bacteria, including Streptococcus viridans,Pseudomonas aeruginosa, nonhemolytic strepto-cocci, and Staphylococcus aureus.2

Both of the complications from granulationtissue in our cohort occurred in patients withmetal stents. The first was in a child with a stentin place for more than 16 months. He was notedto have no granulation tissue on routine bron-choscopy. One month later, he presented to anout-of-state institution for a viral respiratory

Fig 2. Metal Ultraflex stent in left main bronchus 3 months after placement for bronchial stenosis. The stent is covered withgranulation, and the distal left main bronchus is partially obstructed. This patient with Wegener's granulomatosis requiresfrequent bronchial dilations with granulation removal.



infection. A bronchoscopy was immediatelyperformed, and an Nd:YAG laser was used toremove obstructive tissue. Hemorrhage oc-curred and the child died; no autopsy was per-formed. This case stresses the importance ofpatient care by those experienced in stent place-ment and management as well as the cautionthat must be used with lasers. The second pa-tient with excessive granulation had Wegener’sgranulomatosis. The stent satisfactorily openedthe stenotic left main bronchus. However, itsubsequently led to granulation development atboth ends of the stent, requiring removal anddilatation on multiple occasions. Chronic in-flammatory diseases should be aggressivelytreated via medical measures before stent place-ment.

Diminished Mucociliary ClearanceThe retention of mucous secretions is another

complication resulting from the use of some air-way stents. The mesh design used in metals stentshelps to preserve mucociliary clearance.9,10 Un-like plastic stents, metallic stents permit mucosal-

ization through their interstices, thereby allowingadequate mucociliary function10 (Fig 3). Exces-sive formation of granulation tissue can also leadto impaired mucociliary clearance. Lack of muco-ciliary clearance, similar to granulation tissue, canlead to obstruction and infection.5

Patient IntoleranceSome patients do not tolerate long-term stent

placement. In general, stiff, longer stents are notas well tolerated as short, flexible, compliantstents. Also, proximally placed stents (eg, sub-glottis) are not as well tolerated as are distaltracheobrochial stents (eg, left main bronchus).Two of our patients required stent removal dueto poor tolerance. One was a long relativelyinflexible Rusch Y stent, and the other was asubglottic Ultraflex stent.

Placement and RemovalProblems with stent placement and removal oc-

cur more often than we would like. Sometimes thecomplication is simply the inability to place thestent. Stent placement may be difficult due toinherent airway disease, poor stent choice, inade-

Fig 3. Plastic Dumon stent in trachea depicting lack of mucociliary clearance with increased mucus within stent. Theplastic barrier prevents normal clearance of secretions.


quate stent sizing, or lack of special instrumenta-tion. We were unable to place a Rusch Y stent ina patient with mediastinal fibrosis and extrinsiccompression despite predilation with high-pres-sure balloons to over 20 atm (Fig 4).

Complications associated with removal ofstents are much more common. Epithelializationin conjunction with granulation tissue that formsaround metal stents can make their removal verydifficult or nearly impossible in some cases.2,8,10

Placement of metal stents should be regarded aspermanent because the stents become mucosalizedwithin 1 month of placement.9 Some stents requiredeconstruction and piecemeal removal.8 In com-parison, plastic stents have the advantage of usu-ally being easy to remove when the stent is nolonger clinically needed or if it needs to be re-moved for another reason.2,3

Stent FractureAlthough it is an uncommon complication, stent

fracture may occur with metal stents.7 In ourstudy, a patient coughed up small pieces of metal1 year after stent placement. Bronchoscopy dem-onstrated that the stent, an Ultraflex uncovered 4

cm � 20 mm, had broken longitudinally at theposterior tracheal wall. Based on the posteriorlocation of the fracture in the stent, it most likelybroke due to repetitive compression from theesophagus during swallowing. Stent breakage re-quires urgent removal to minimize the upper air-way affects of stent collapse and subsequent distalfragmentation of metallic pieces leading to inflam-matory lung disease (Fig 5). There are also casereports of metal stents collapsing due to physio-logic compressive forces without actually break-ing into pieces.4,5

Other Complications and ObservationsAlthough they are rare, life-threatening compli-

cations can occur with the use of airway stents.Several case reports demonstrate the risk of he-moptysis and possible death.11,12 Balloon-expand-able metal stents are more likely to erode thetracheobronchial tree and lacerate major bloodvessels. It is therefore vital not to overexpand theballoon with metallic airway stents. Also, the useof laser on or near metal stents may lead to hightransmission of heat energy to major blood vesselswith disastrous consequences.6

Fig 4. Trachea of patient with mediastinal fibrosis. A stent was not able to be placed or expanded due to the extremefibrotic nature of the underlying disease.



Most of our complications occurred in benigndisease. The difference between the occurrencesof complications may be due to the fact that stentsare mostly used for palliative care in malignantdisease. Therefore, patients with malignant dis-ease may die secondary to progression of theirunderlying disease before experiencing stent com-plications.

Complication Avoidance andManagement

Of course, the best way to avoid complicationsis to keep them from occurring in the first place.The most important thing that can be done toavoid complications with airway stents is towisely choose the appropriate therapy. This in-

Fig 5. (A) Severe symptomatic tracheomalacia before stent placement. (B) Immediately after the placement of 3Ultraflex stents (1 tracheal and 2 bronchial). The short right main bronchus stent was coughed up after the patient wokeup. (C) Posterior tracheal Ultraflex stent breakage. Patient presented 1 year after initial placement “coughing up bits ofmetal.” The longitudinal stent fracture was likely precipitated from repeated compression from swallowing. (D) View offractured tracheal Ultraflex stent immediately after removal. The stent was removed in multiple pieces with difficulty.Ciliated mucosa lined the inner lumen of the stent.


cludes deciding when it is appropriate to use astent. This has previously been reported.1,4 Afterdetermining that the use of a stent is a part of acomprehensive treatment plan, the most importantpart of stent placement is deciding which stent touse. Multiple factors are considered when choos-ing a stent type: whether the stent is to be perma-nent or temporary, whether the stent is for a be-nign or malignant condition, where the stent is tobe placed, and whether the stent is being placed inconjunction with other treatment modalities (Ta-ble 2).

It is important to gather as much information aspossible to make these decisions. Direct visualiza-tion of the obstruction should be made via bron-choscopy. Computed tomography or magnetic res-onance imaging (MRI) should be used to identifythe relationship of the obstructed region to theadjacent structures.

We support the MAST approach because itcombines the efforts of several specialties: com-monly interventional radiology, pulmonology, andanesthesiology along with otolaryngology.1,4,5 Inaddition, cardiothoracic surgery and oncology canprovide additional expertise and assistance in

many cases.1 At our institution, the otolaryngolo-gist leads the team. All team members are in-volved in the case and provide input and expertisefrom their respective fields to make the best deci-sions on everything from stent type, size, andlocation to the proper procedural approaches.

The whole focus of airway stents is to protectthe airway. For this reason, we recommend usingrigid bronchoscopy when placing most stents orremoving all stents. The use of a MAST can againprove advantageous in this situation by cultivatinga working plan with the anesthesiologist to main-tain the airway while sharing it to provide stentrelated therapy.

After the proper placement and use of appropri-ate adjuncts (eg, laser, tissue debulking, brachy-therapy, topical mitomycin C, steroids, cryother-apy, and balloon dilatation), the use of acomprehensive follow-up plan is essential to dis-covering possible complications. The early iden-tification of complications allows for easier man-agement. Various methods of follow-up can andshould be used as appropriate; these include serialbronchoscopy, chest radiography, pulmonaryfunction tests, and computed tomography. MRI is

Fig 5. (E) Airway 1 year after tracheal stent removal (compare with A). The patient remains asymptomatic with a patentstiffened trachea due to previous scarring from the tracheal stent. Only the left main bronchus stent remains.



helpful to follow patients with obstructive airwaysoft tissue masses but cannot be used in patientswith stainless steel stents (eg, Palmaz, Wallstent).Nickel-titanium stents (eg, Ultraflex) and plasticstents can be followed with MRI.

Appropriate management of complicationswhen they occur is key to good follow-up. If thecomplication is not life threatening, the same stepsused originally to determine the need for the stentcan be followed to determine the need and abilityto maintain, remove, or replace the stent.

Stent migration is remedied by endoscopicrepositioning or removal and replacement with abetter-fitting metallic stent. Stent-induced gran-ulation is treated by a variety of methods. En-doscopic mechanical debridement, topical mit-omycin C, laser, steroid therapy, cryotherapy,and balloon dilatation are common modalitiesused in our practice to treat granulation. Anti-biotics are routinely administered, because in-fection is normally associated with airway gran-ulation. Complications in stent placement areusually related to stent choice and instrumenta-tion. Dumon and Rusch Y stents have specifi-cally designed insertion devices that signifi-cantly aid stent placement.

Stent removal is performed in the operatingroom under general anesthesia using rigid andflexible bronchoscopy. Cardiothoracic surgeryconsultation and cardiopulmonary bypass shouldbe on standby for cases with high risk.6 A venti-lating laryngotracheoscope (Karl Storz, CulverCity, CA) is placed under telescopic guidance,with the tip proximal to the retained stent. Thissuspendable instrument allows proximal ventila-tion, airway control, and large ports for opticalforceps.1 The flexible bronchoscope is placedthrough the laryngotracheoscope to visualize thedistal stent as needed. The proximal edges arecarefully dissected inwardly away from the airwaywall along the complete proximal perimeter withthe alligator optical forceps. The large alligatoroptical forceps firmly grasp opposing sides of theproximal stent. The ventilating laryngotracheo-scope is slowly advanced and the stent is retractedinto the laryngotracheoscope. The stent is re-moved as the laryngotracheoscope remains inplace to tamponade hemorrhage from the abradedmucosa. Topical oxymetazoline 0.05% on 1⁄4-inch

pledgets may be endoscopically positioned to helpcontrol bleeding. If bleeding persists, intubationwith a cuffed tube distal to the stented area pro-tects the airway. Persistent bleeding or hemody-namic shock may require urgent thoracic surgicalintervention and cardiopulmonary bypass. Metalstents placed in the left main bronchus over aprolonged period of time are especially risky toremove. Because the left main bronchus is be-tween the descending aorta and pulmonary artery,removal of a metal stent in this precarious positionmay lead to inadvertent damage to major vesselsand death. External removal of the stented leftmain bronchus with reanastomosis is also techni-cally difficult to successfully perform.

The Palmaz stent tends to maintain structuralintegrity on removal. The Ultraflex and Wallstentboth tend to break up on removal, and meticulouspiecemeal extraction is necessary. Plastic stentsare much easier to remove.

After the metal stent is successfully removed,the circumferential denudement of the mucosamay be significant. To help prevent subsequentstenosis, we place topical Mitomycin C (1%) on1⁄4-inch pledgets over the previously stented areafor several minutes. The antifibroblast effect oftopical mitomycin inhibits subsequent scar forma-tion.

On the horizon are several innovations thatmight be beneficial in the prevention of complica-tions. Among these are drug-eluting stents forinhibition of granulation tissue or malignant tumoringrowth and hydropolymer balloon dilation cath-eters that make it easier to apply circumferentiallocal drug delivery. New Palmaz Genesis stentsare now available that are more flexible and con-formable than the standard Palmaz stents and havenonirritating rounded edges.

CONCLUSIONSThe proper use of airway stents in conjunction

with the appropriate use of adjuncts and compre-hensive follow-up is very useful for the treatmentof airway pathology, in both benign and malignantdisease. However, stent-related complicationstend to occur more often with benign disease. Werecommend that stents not be used as the first lineof therapy for benign conditions, especially whenthe stent is expected to remain in place for a


prolonged period of time. The use of stents inproperly selected patients with malignant diseaseis encouraged as a palliative measure.

REFERENCES1. Jones LM, Mair EA, Lyon RD, et al. Multidisciplinary

airway stent team: a comprehensive approach and proto-col for tracheobronchial stent treatment. Ann Otol RhinolLaryngol 2000;109:889-98.

2. Jacobs JP, Quintessena JA, Botero LM, et al. The role ofairway stents in the management of pediatric tracheal,carinal, and bronchial disease. Eur J Cardiothorac Surg2000;18:505-12.

3. Sommer D, Forte V. Advances in the management ofmajor airway collapse. Otolaryngol Clin North Am 2000;33:163-77.

4. Mehta AC, Dasgupta A. Airway stents. Clin Chest Med1999;20:139-51.

5. Dasgupta A, Mehta AC. Use of Wallstents in centralairway obstruction. Oper Techn Otolaryngol Head NeckSurg 1999;10:264-70.

6. Filler RM, Forte V, Chait P. Tracheobronchial stentingfor the treatment of airway obstruction. J Pediatr Surg1998;33:304-11.

7. Susanto I, Peters JI, Levine SM, et al. Use of balloon-expandable metallic stents in the management of bron-chial stenosis and bronchomalacia after lung transplanta-tion. Chest 1998;114:1330-5.

8. Rafanan AL, Mehta AC. Interventional chest radiology:stenting of the tracheobronchial tree. Radiol Clin Nor Am2000;38:395-408.

9. Furman RH, Backer CL, Dunham ME, et al. The use ofballoon-expandable metallic stents in the treatment ofpediatric tracheomalacia and bronchomalacia. Arch Oto-laryngol Head Neck Surg 1999;125:203-7.

10. Ruegemer JL, Perkins JA, Azarow KS, et al. Effect of thePalmaz balloon-expandable metallic stent in the tracheaof pigs. Otolaryngol Head Neck Surg 1999;121:92-7.

11. Cook CH, Bhattacharyya N, King DR. Aortobronchialfistula after expandable metal stent insertion for pediatricbronchomalacia. J Pediatr Surg 1998;33:1306-8.

12. Urschel JD. Delayed massive hemoptysis after expand-able bronchial stent placement. J Laparoendosc Adv SurgTech A 1999;9:155-8.

Table 2. Comparison of likely complications by stent type

Stent type Migration GranulationMucociliaryclearance

Patient tol-erance Placement Removal Breakage

Palmaz �� Wallstent �� Ultraflex �� Dynamic Y � � �� Dumon ��

�, Less common complication; ��, more common complication.

