Qualitative criteria
Quantitative criteria
Histology
Extent (vertical length)
Benign
Normal
Malignant
Focal
Multifocal
Diffuse
Mechanism
Severity of airway narrowing
Extrinsic
Normal
Intraluminal
Mild (<50 %)
Exophytic
Moderate (50–75 %)
Infiltrative
Severe (75–100 %)
Strictures
Mixed
Dynamic features
Functional impairment
Fixed
Normal
Dynamic
Mild
Moderate
Severe
Table 42.2
Investigation/Intervention Comparator Outcome (PICO) questions for the role of airway stent insertion in benign central airway obstruction
PICO question 1 | Among patients with CAO from benign tracheal or bronchial stenosis, does airway stent insertion improve health outcomes (defined as performance status, quality of life, frequency and duration of hospitalizations, incidence of respiratory failure, need for repeat bronchoscopic procedures, and survival)? |
PICO question 2 | Among patients with CAO from benign tracheal or bronchial stenosis, does airway stent insertion adversely affect health outcomes (defined as performance status, quality of life, frequency and duration of hospitalizations, incidence of respiratory failure, need for repeat bronchoscopic procedures, and survival)? |
PICO question 3 | Among patients with CAO from tracheobronchomalacia, does airway stent insertion improve health outcomes (defined as performance status, quality of life, frequency and duration of hospitalizations, incidence of respiratory failure, need for repeat bronchoscopic procedures, and survival)? |
PICO question 4 | Among patients with CAO from tracheobronchomalacia, does airway stent insertion adversely affect health outcomes (defined as performance status, quality of life, frequency and duration of hospitalizations, incidence of respiratory failure, need for repeat bronchoscopic procedures, and survival)? |
Search Strategy
Study Identification
Systematic methods were used to find relevant studies, assess their eligibility for inclusion, and evaluate study quality. An attempt was made to retrieve all published studies that reported on post-stent insertion outcomes for patients with benign CAO since the introduction of dedicated airway stents. The online database MEDLINE was searched for papers published in English between January 1st, 1990 and September 10th, 2013. The start date was selected in order to assure inclusion of relevant studies on the subject matter at the time of the introduction of the dedicated silicone airway stent in the early 1990s in Europe. The following terms were used in Pubmed advanced search engine: Search details: (((((((((((“stents”[MeSH Terms] OR stenting[Text Word]) AND “airway obstruction”[MeSH Terms]) OR “tracheal stenosis”[MeSH Terms]) OR bronchial stenosis[Text Word]) OR laryngotracheal stenosis[Text Word]) OR subglottic stenosis[Text Word]) OR “tracheomalacia”[MeSH Terms]) OR “tracheobronchomalacia”[MeSH Terms]) OR “bronchomalacia”[MeSH Terms]) AND English[Language]) AND (“1990/01/01”[EDAT] : “3000”[EDAT])) AND “adult”[MeSH Terms]. Additional articles were captured by reviewing the reference lists from identified studies and pertinent review articles.
Study Eligibility and Data Abstraction
Articles deemed potentially eligible for inclusion were reviewed and assessed according to predefined criteria (Fig. 42.1). Data were summarized in a table of evidence (Table 42.3) based on the type of study, patient demographics, type of benign CAO, stent type, length of follow up, and reported outcomes including benefits and harms [1–56]. Specific outcomes including performance status, lung function, quality of life, incidence of respiratory failure, need for repeat bronchoscopic procedures, and survival were included when available. The population of interest for this systematic review was adult patients. Stent insertion options included silicone, metal and hybrid stents inserted using rigid, flexible bronchoscopic and fluoroscopic techniques.
Fig. 42.1
Study inclusion form illustrating inclusion and exclusion criteria
Table 42.3
PICO table of evidence summarizing original research articles on stent insertion for benign central airway obstruction for years 2004–2013
Reference | Study design | Patients (indications)/follow up time | Type of intervention/comparison | Primary outcome | Adverse events/risk factors | Evidence quality |
|---|---|---|---|---|---|---|
Redmond et al. [1] | Retro; case series | N = 22 lung transplant | Metallic stents (N = 43) via rigid bronch | 42 % (18/43) complications | Stent collapse, fracture, migration, granulation tissue, and coughing up pieces of stent | Very low |
BM; BS | Comparison: none | 9 % (4/43) required stent removal | ||||
Mean 285 days | ||||||
Terra et al. [2] | Retro; cohort study | N = 92 with benign, inoperable TS | T tubes | Successful decannulation (no need for intervention for >6 months) achieved in 19/92 | Tracheostomy before stent : threefold increase in the likelihood of the patient remaining with a tracheal stent | Low |
Mean 34.3 +/− 33.9 months | Dumon stents | |||||
Y stents | ||||||
Comparison: none | ||||||
Chen et al. [3] | Case series | N = 21 with PITS; 20 pts had stent removal | Covered SEMS (N = 27) inserted fluoroscopically | Improved airway patency, FEV1 and Hugh-Jones classification of greater than one grade post stent removal | Complications in 19 (91 %): granulation tissue formation (n = 18), stent migration and stent expectoration (n = 2), mucus plugging (n = 1), and halitosis (n = 6) | Very low |
Median for stent placement = 5 months | CT and bronch follow up | |||||
Comparison: none | ||||||
Verma et al. [4] | Retro; case series | N = 17 inoperable, post TB stenosis Median 72 months (12–114) | Silicone stents (N stent) Comparison: none | Increase in the FEV1% and FVC% (Δ26.5 % and Δ16.5 %, respectively) in the long term; The median duration for which N-stents tolerated 7.9 (3–11) years | Granulation tissue formation (76 %), migration (70 %), and mucostasis (17 %) | Very low |
Gallo et al. [5] | Retro; case series | N = 70 with LTS | T tube (either a single dilation or with endoscopic/open neck surgery) | 77.1 % (54/70) were decannulated | 13 % were decannulated after more than 5 surgical procedures; patients over 60 years of age and with a higher grade of stenosis had a significantly lower success rate | Very low |
Iatrogenic 55 | Total of 257 surgeries | 72.2 % underwent 3 or fewer surgical procedures; no significant correlation between the rate of decannulation and gender, etiology, site of stenosis or surgery | ||||
Post traumatic 11 | Comparison: none | |||||
Others 4 | ||||||
Jeong et al. [6] | Retro; case series | N = 30 patients with inoperable post op stenosis 19/30 (63 %) had stent placement | 106 procedures (balloon, bouginage, Nd:YAG, and stent insertion) | 37 % had stents removed at a median of 7 months after insertion | Stent-related late complications (70 %): restenosis (43 %), granulation tissue (33 %), migration (32 %), mucostasis (30 %), and malacia after stent removal (16 %) | Very low |
Median 34 months | Follow up bronch | |||||
Comparison: N/A | ||||||
Lim et al. [7] | Retro, case series | N = 55 patients with inoperable PITS | Silicone stent placement after laser and mechanical dilation | Stent removal in 40 % of the patients after median 12 months | The stent could be removed in those pts without cardiac disease ((OR) = 12.195] and the intervention was performed within 6 months after intubation (OR = 13.029) | Very low |
Median 12 months | Comparison: none | In 60 %, surgery was needed after initial stabilization | ||||
Chen and Ruan [8] | Retro; case series | N = 13 pts with LTS; 9 with 1 stent; 4 with two stents Follow up: N/R | Nickel-titanium alloy stent (SEMS) Comparison: none | Glottic and/or subglottic extension of cervical tracheal stenosis (n = 6), new tracheal stricture (n = 4), severe left bronchial stricture with massive left pulmonary collapse (n = 1), and cervical tracheoesophageal fistula (n = 2) | 6 patients with glottic and/or subglottic to cervical tracheal stenosis underwent successful laryngotracheal reconstruction; 1 patient with tracheoesophageal fistula died from massive hemorrhage and asphyxiation induced by the stent | Very low |
Lari et al. [9] | Retro; case series | N = 12 pts with post transplant airway complications (BI stenosis or malacia) | T-Tube in BI | FEV1 improved post stent placement | Migration (33 %) | Very low |
Follow up: N/R | Comparison: N/A | |||||
Perotin et al. [10] | Retro; case series | N- = 23 pts with weblike (61 %) or complex (39 %) TS, located in the upper part of the trachea Follow up: 41 ± 34 months post treatment | Stent placement (18 %): 2 for weblike and 2 for complex strictures when the stricture was at 3 +/− 1 cm below the cords Comparison: N/A | Recurrences were frequent (30 % at 6 months, 59 % at 2 years, and 87 % at 5 years) with a delay of 14 +/− 16 months N = 2 recurred in the stent group (50 %) | No correlation between the risk or the number of recurrence and the type (weblike versus complex), the severity of obstruction, the height of stenosis (<1 cm versus >1 cm), the distance from the vocal cords or the endoscopic treatment performed | Very low |
Lim et al. [11] | Retro; case series | N = 71 pts with Post TB stenosis Median 12.5 months | Silicone stents Comparison: none | Stent removal in 40/71 pts at a median of 12.5 months; in 27, stent was re-inserted; 4 had surgery | Predictors of successful stent removal: atelectasis <1 month before bronchoscopic intervention, and absence of complete lobar atelectasis | Very low |
Chung et al. [12] | Retro; cohort study | N = 72 with benign and 77 with malignant CAO; 429 days for the benign group | SEMS (N = 116) placed for benign disorders Comparison: none | Symptoms improved more after SEMS insertion for benign than in malignant disease (76.7 % vs. 51.6 %; p < 0.0001) | Complication rate after SEMS in patients with benign conditions was higher than that in patients with malignancy (42.2 % vs. 21.1 %; p = 0.001) | Low |
Fernandez-Bussy et al. [13] | Retro; cohort study | N = 223 pts with 345 anastomoses | Stent insertion after failed balloon dilation | FEV1 improved post stent insertion | Granulation 57.3 % of patients | Low |
N = 70 (20.23 %) anastomoses complications post transplant | N = 631 bronchoscopic interventions in 52 pts | |||||
Follow up: N/R | N = 33 had BS and BM | |||||
N = 18 with BS | ||||||
N = 47 had stent placement | ||||||
Comparison: none | ||||||
Charokopos et al. [14] | Retro; case series | N = 12 with PITS | SEMS in 11pts; follow up bronchoscopy and CT | Immediate improvement in all 11/12 pts | 2 migration post procedure | Very low |
3 with subglottic stenosis | Comparison: none | 4 granulation tissue 12–43 months requiring electrocautery or tracheostomy | ||||
Follow up: 6–96 months | ||||||
Tan et al. [15] | Retro; case series | N = 3 pts with post transplant BI strictures | SEMS (covered) n = 6 | 5/6 migrated immediately post placement | Stent retrieval successful in 3/5 | Very low |
Follow up: N/R | Comparison: none | Secretions in 6/6 | ||||
Fruchter et al. [16] | Retro; case series | N = 24/305 (7.8 %) pts with post transplant BM and BS | SEMS retrieval via flexible bronch using moderate sedation | 25 % required stent removal due to granulation and obstruction by mucus | Stent was removed in 5/6 patients | Very low |
Follow up: 30 months | Comparison: none | |||||
Yu et al. [17] | Retro; case series | N = 32 pts with TS | SEMS follow up with CT (3D recon) | 17/32 had stent fracture detected by 3D recon CT | Fracture of SEMS can be predicted by CT measurements | Very low |
Median 865 days | Comparison: none | |||||
Alazemi et al. [18] | Retro; case series | N = 46 pts with SEMS; 80 % were for benign CAO | SEMS removal (N = 55) | Median no of removal procedures/encounter = 1 | The estimated median total cost per encounter to remove the stents was $10,700 | Very low |
Mean in situ SEMS 292 days | Comparison: none | Median no of total procedures/encounter = 2 | The measured outcomes were statistically significantly better when in situ stent duration was < or = 30 days (P < 0.05) | |||
Hospitalization and ICU admission in 78 % and 39 % of the encounters with a median length of stay of 3.5 and 0 days, respectively | ||||||
Kim et al. [19] | Retro; case series | N = 41 pts with TS | T tube placement | Successful decannulation | Predictors of decannulation failure: The longitudinal extent of stenosis and greater circumferential involvement | Very low |
Follow up: N/R | Comparison: none | Age, sex, and multiplicity and severity of stenoses were not significantly related to successful decannulation | ||||
Chung et al. [20] | Retro; case series | N = 67 pts with benign TS and TM | SEMS placement (N = 75) | 47.8 % had granulation | Structural airway obstruction prior to SEMS implantation predicts obstructive granulation tissue formation after SEMS implantation (odds ratio: 3.84; 95 % CI: 1.01–8.7; P = 0.04) | Very low |
Median = 106 days | Comparison: none | Time to granulation tissue detection was shorter in patients with structural airway obstruction before SEMS implantation (structural airway obstruction vs. dynamic collapse airway: median (IQR] 95 (38–224, n = 26] vs. 396 days (73–994, n = 9]; P = 0.02) | ||||
Melkane et al. [21] | Retro; cohort study | N = 33 consecutive patients with Post intubation LTS; The endoscopic candidates were chronically ill patients presenting with simple, strictly TS not exceeding 4 cm in length | N = 19 endoscopic treatments | 50 % of the patients were decannulated in the surgically treated group versus 84.2 % in the endoscopically treated group (p = 0.03) | In the surgically treated group, 2/14 patients needed more than one procedure versus 8/19 patients in the endoscopically treated group | Low |
Follow up: 6 months | Stents were placed if the stenosis was associated with TM or exceeded 2 cm in total length | |||||
Comparison: N = 14 surgical treatment: healthy patients presenting with complex | ||||||
TS, subglottic involvement or associated TM | ||||||
Rahman et al. [22] | Retro; case series | N = 115 pts with benign TS due to PITS (N = 76) PTTS (N = 30), Wegener’s granulomatosis (N = 2), sarcoidosis (N = 2), amyloidosis (N = 2) and ITS (N = 3) | Flexible bronchoscopy balloon dilatation and laser treatment (N = 98) | The overall success rate was 87 % | 26 % died, mostly due to exacerbation of their underlying conditions | Very low |
Median 51 months | Stent was placed in 33 pts of whom 28 also underwent brachytherapy | |||||
Comparison: none | ||||||
Ko et al. [23] | Retro; case series | N = 55 procedures for TS Follow up: N/R | T tubes N = 46 Dumon silicone stent N = 9 Comparison: none | Granulation (23 procedures, 41.82 %) | The granulation complication rate was higher in those with a stent-to-vocal fold distance of <10 mm | Very low |
Nam et al. [24] | Retro; case series | N = 11 pts with carinal stenosis included post TB stricture in 7 pts (64 %), PITS in 2 (18 %), postoperative TM in 2 (18 %) | Balloon dilation; Nd:YAG laser resection, or bougienation (by rigid bronchoscopy) to dilate the airway, followed by placement of the Natural Y stent | 100 % subjective symptomatic relief immediately after stent placement | No procedurally related deaths or immediate major complications occurred | Very low |
Median duration of stent placement = 439 days | Comparison: none | Stent-related late complications included granulation (64 %) and mucostasis (18 %) | ||||
Fernandez-Bussy et al. [25] | Retro; cohort study | N = 24 consecutive pts with post transplant bronchial anastomoses complications | SEMS N = 49 (hybrid) via flexible bronchoscopy | The average degree of stenosis decreased from 80 % to 20 % | Complications included granulation in 10 stents, migration in 9, mucus in 2, and fracture in 3 | Low |
BS in 12, bronchomalacia in 12, BS plus | Adjunctive procedures included EC in 1, balloon dilatation in 7, and EC plus balloon dilatation in 4 | The average increase was 0.28 L in FVC and 0.44 l in FEV1 | ||||
BM in 20, and partial bronchial dehiscence in 5 | Comparison: none | |||||
Abi-Jaoudeh et al. [26] | Retro; case series | N = 41 pts with post transplant BS | Stent placed when balloon dilation failed; 56 % received a stent because of balloon dilation failure or stenosis recurrence | After the first treatment, airway patency was higher in patients treated with stents (71 %) than in those who underwent bronchoplasty (19 %) (P = 0.037) | Mean survival in patients with stents was longer than that in those who underwent bronchoplasty (82 vs 22 months, respectively) stent insertion: associated with a 66 % reduction in the risk of death (P < 0.02) | Low |
10–40 months | Comparison: balloon dilation | Airway patency: 40 months for stented strictures versus 10 months for strictures treated with bronchoplasty (P < 0.02) | ||||
Dyspnea and cough were improved after intervention (P < 0.001), and FEV1 was improved by 17 % (P < 0.00003) at last follow-up | ||||||
Gottlieb et al. [27] | Retro; cohort study | N = 65 (9.2 %) out of 706 lung transplant | 111 (91 % uncovered) SEMS were inserted a median (range) 133 (55–903) days after lung transplantation | Clinical improvement in 80 % of pts | Re-stenosis occurred in 34 (52 %) out of 65 pts at 85 (7–629) days after insertion | Very low |
Recipients with post transplant BS | Comparison: none | The FEV1 increased by 21 +/− 33 % (mean +/− SD) | Stent insertion before post-operative day 90 was independently associated with an increased risk of re-stenosis (HR 3.29, 95 % CI 1.50–7.18; p = 0.003); 40 % of pts had new bacterial airway colonization after SEMS insertion | |||
777 (7–3.655) days | In SEMS patients, 5-year survival was significantly lower than in the total cohort (60 % versus 76 %; p = 0.02) | |||||
Park et al. [28] | Retro; case series | N = 32 pts with PITS | Silicone stent (N stent) | 100 % symptomatic and spirometric improvement without immediate complications | Late complications were migration (34 %), mucostasis (31 %), granulation (38 %) and re-stenosis (40 %) | Very low |
Median 22 months | Nd:YAG laser, ballooning or bougienage was followed by N stent insertion | Removal of the stent without re-stenosis was successful in 38 % of pts at a median time of 7 months after insertion | ||||
Comparison: none | The stent could not be removed or needed reinsertion in 31 % of patients; 16 % of pts had surgery after initial stenting | |||||
Carretta et al. [29] | Retro; cohort study | N = 75 pts with benign TS complex lesions or comorbidities | T-tube in 51 pts with contraindication to surgery (group I), a temporary measure in 15 pts prior to surgery (group II), and in 9 pts (group III) for complications of airway reconstruction | In group I, the T-tube was removed in 24 % of pts after 35.3 +/− 8.2 months following resolution of the stenosis | Migration in 3 (4 %) pts, granulation in 14 (19 %), subglottic edema in 3 (4 %), and mucus retention in 7 (9 %); Treatment of complications (tracheostomy cannula, steroid infiltration, Argon/laser coagulation bronchoscopy) was required in 27 % of pts | Low |
N = 7 had undergone unsuccessful treatment with Dumon stents | Comparison: none | In group II, the T-tubes were maintained in place before surgery for 17.1 +/− 4.8 months | ||||
Follow up: 5 years | In group III, 3 stents were removed following tracheal healing after 115.3 +/− 3.7 months | |||||
After 5 years the stents were in place in 82 %, 7 % and 100 % of the pts, respectively in groups I, II and III | ||||||
Dooms et al. [30] | Retro; case series | N = 17 pts with 10 stents were deployed in a structural PITS Other indications were multinodular goiter, anastomotic stricture, Post TB stenosis, damaged cartilage and relapsing polychondritis | 7 Silmet, 8 Taewoong 5 Alveolus stents | Short-term (<12 weeks after stent deployment) complication rate was 75 %, requiring stent removal in 60 % | Migration 65 % | Very low |
Follow up:12 weeks | Comparison: none | Stent fracture 15 % | ||||
Shriveling of the stent in 10 % | ||||||
Granulation 10 % | ||||||
Thistlethwaite et al. [31] | Retro, cohort study | N = 20/240 (8.3 %) pts with post transplant BS (>50 % narrowing) | Dilation and silicone stent placement | The mean time to diagnosis of BS was 81.5 +/− 26.9 days | Pulmonary aspergillosis and pseudomonal infection, age less than 45 years, and early rejection correlated with BS; ischemic time, side of transplant, and preoperative disease did not | Low |
Follow up: 4.9 +/− 3.5 years after stent removal | Comparison: none | Airway patency and symptom improvement in 18/20 pts | ||||
N = 16 pts were able to have their stents removed at a mean of 362.3 +/− 126.4 days with permanent resolution of airway stenosis; Overall survival was similar for patients with and without BS | ||||||
Galluccio et al. [32] | Retro; cohort study | N = 209 consecutive pts with PITS (N = 167) and PTTS (N = 34) | Mechanical dilatation, laser resection and placement of a silicone stent | Simple stenoses (N = 167) treated by 346 endoscopic procedures (mean of 2.07/patient), 16 stents and 1 end-to-end anastomosis | Among the 42 complex stenoses, 9 were immediately treated by surgical resection and the remaining 33 lesions underwent 123 endoscopic procedures (3.27/patient), with 34 stents and 1 end-to-end anastomosis subsequent to recurrence after stent removal | Low |
8 other benign TS | Comparison: none | N = 38 granulomas treated by 59 procedures (1.56/patient) | In this group the success rate was 69 % | |||
Follow up: 2 years | N = 97 concentrical stenoses by 228 procedures (2.35/patient) and 32 web-like lesions with 59 operative endoscopies (1.84/patient) Overall success rate was 96 % | |||||
Shlomi et al. [33] | Cohort study | N = 19 pts with benign obstructions and 11 with post transplant stenosis on immunosuppressive therapy | SEMS in transplant | Granulation was significantly lower in the transplant recipients than in the non-transplant pts at 3, 15 and 18 months | Transplant recipients underwent significantly fewer laser resections and brachytherapy treatments for stent granulation | Low |
Follow up: 2 years | Comparison: SEMS in other benign strictures | |||||
Chan et al. [34] | Retro; case series | N = 35 pts with inoperable benign CAO | 82 SEMS (67 % Ultraflex, 33 % Wallstent)
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