Management of non-life-threatening, nonmalignant subglottic and tracheal stenosis in adults

INTRODUCTION — Subglottic stenosis and tracheal stenosis (TS) are broad terms that describe a stricture or narrowing of the subglottic and tracheal lumen, respectively. Subglottic stenosis and TS can be due to a diverse group of malignant or nonmalignant conditions and can cause significant morbidity and mortality. Management varies considerably depending on the etiology.

This review will focus on the management in adults of nonmalignant, non-life-threatening stenosis at any level between the subglottis and the main carina of the trachea. Diagnostic evaluation of subglottic stenosis and TS, management of stenosis due to malignant etiologies, and management of tracheomalacia are discussed separately.

●(See "Tracheomalacia in adults: Clinical features and diagnostic evaluation".)

●(See "Clinical presentation, diagnostic evaluation, and management of malignant central airway obstruction in adults".)

●(See "Presentation and diagnostic evaluation of non-life-threatening and nonmalignant subglottic and tracheal stenosis in adults".)

TERMINOLOGY AND SCOPE — For clarity, we use the following terms:

●Laryngeal and laryngotracheal stenosis – Laryngeal stenosis involves the larynx only while laryngotracheal stenosis describes abnormal narrowing of the airway involving both the larynx and trachea. The latter may include the supraglottic region of the larynx (ie, above the vocal cords including the epiglottis), the glottic region of the larynx (ie, at the level of the vocal cords), and the subglottic region of the larynx that connects to the trachea (ie, below the vocal cords) (figure 1).

●Tracheal stenosis – TS is an abnormal narrowing of the tracheal lumen below the lower limits of normal. Normal tracheal anatomy and dimensions are discussed separately. (See "Presentation and diagnostic evaluation of non-life-threatening and nonmalignant subglottic and tracheal stenosis in adults", section on 'Normal anatomy and tracheal dimensions'.)

●Tracheobronchial and bronchial stenosis – Tracheobronchial stenosis is abnormal narrowing that involves the trachea as well as the bronchus while bronchial stenosis involves the bronchus only (figure 2).

For the purposes of this review, we will mostly be discussing the management of nonmalignant stenosis of the subglottis and trachea to the level of the main carina. We will not be discussing the following conditions which are mostly described separately:

●Tracheal narrowing due to tracheomalacia or conditions including impacted mucus or thrombus. (See "Tracheomalacia in adults: Clinical features and diagnostic evaluation".)

●Life-threatening obstruction. (See "Clinical presentation, diagnostic evaluation, and management of malignant central airway obstruction in adults", section on 'Life-threatening central airway obstruction'.)

●Bronchial stenosis. Management may be similar if the stenosis is proximal, but unlike TS, many distal bronchial lesions cannot be treated with local bronchoscopic therapy.

GENERAL PRINCIPLES OF THE APPROACH — We advocate a multidisciplinary approach to patients with complex airway disease including evaluation by and discussion amongst interventional pulmonary, otolaryngology head and neck surgery, and thoracic surgery experts. Data to support therapeutic strategies are limited since most studies describe outcomes in stenosis due to several different types of etiologies. In addition, there are no widely accepted standardized therapeutic approaches, such as choice of bronchoscopic technique or when to refer for surgical management. Thus, therapeutic strategies described in this topic are representative of our practice, recognizing that practice may differ in individual centers with varying levels of expertise.

Early referral — Patients with nonmalignant, non-life-threatening subglottic stenosis or TS should be referred early in their course to a center of expertise in therapeutic bronchoscopy and/or airway surgery since this expertise is not universally available at all pulmonology or thoracic surgery centers.

In our center, we fully characterize the stenosis to inform our therapeutic plan (table 1). Details of this characterization are discussed separately. (See "Presentation and diagnostic evaluation of non-life-threatening and nonmalignant subglottic and tracheal stenosis in adults", section on 'Characterization'.)

Treat the underlying disorder — In all cases of subglottic stenosis and TS, we treat the underlying cause when feasible (eg, antimicrobial agents for infectious etiologies, anti-inflammatories for vasculitis and inflammatory disorders, antireflux measures for reflux-induced disease, such as idiopathic subglottic stenosis).

In some patients, this may be sufficient to alleviate symptoms and restore patency, although in many cases, local bronchoscopic therapies are additionally needed while targeted therapy of the underlying cause is ongoing. Regardless of the underlying cause, if the lesion is due to old fibrotic scar, therapy targeted at the etiology is unlikely to be effective. In such cases, local bronchoscopic therapy or surgery may be the only option. (See 'Initial therapy: Bronchoscopy' below and 'Surgery' below.)

Treatment of specific disorders is discussed below and listed in the table (table 2). (See 'Management of stenosis due to specific etiologies' below.)

ASYMPTOMATIC PATIENTS

Observation — For most patients with non-life-threatening, nonmalignant subglottic stenosis or TS who are asymptomatic, we treat the underlying cause, if feasible (see 'Treat the underlying disorder' above). We do not typically treat the stenosis itself unless it is severe (eg, >75 percent stenosis or <5 mm cross sectional diameter, although severe is poorly defined), the patient has developed complications (eg, significant hemoptysis or mucus impaction), or the stenosis is likely to be problematic in the future (eg, expected problems during future intubation or decannulation). The rationale for observation is based upon our experience, the avoidance of a potentially unnecessary procedure, and its complications, such as airway epithelial injury, which can make future treatments more challenging.

Examples include patients with mild trauma-related fibrous strictures and patients with mild stenosis from extrinsic compression due to an enlarged goiter or lymph node, or mild cases from connective tissue disease or vasculitis without potential for progression.

Asymptomatic patients need to be closely monitored since patients can lose a significant amount of airway cross-sectional area prior to the development of symptoms. Patients do not typically develop exertional dyspnea until the tracheal diameter is approximately 8 mm and do not develop stridor until the tracheal diameter is 5 mm. Thus, in this population, we periodically follow patients using clinical history and examination and pulmonary function testing, specifically flow volume loop assessment (eg, every 6 to 12 months). We do not routinely perform chest computed tomography (CT) or bronchoscopy during follow-up.

●For patients who remain asymptomatic and in whom lung function improves or remains stable, no intervention is required. Some patients may remain stable for prolonged periods.

●For those who develop symptoms suggestive of progressive stenosis or complications, we perform prompt evaluation with chest and neck CT with a dedicated airway protocol and bronchoscopy. If worsening stenosis is confirmed, restoration of airway patency is indicated. We apply the same principles as those with symptomatic disease and generally start with local bronchoscopic therapies, such as balloon dilation with or without local ablative therapy. Clinical symptoms suggestive of stenosis and local bronchoscopic therapies are described separately. (See "Presentation and diagnostic evaluation of non-life-threatening and nonmalignant subglottic and tracheal stenosis in adults" and 'Restore airway patency' below.)

SYMPTOMATIC PATIENTS — Because subglottic stenosis and TS encompasses numerous distinct disease entities, the management of symptomatic disease varies greatly depending on the underlying condition. Nonetheless, our general principles of management include the following:

●Targeted treatment at the underlying etiology. (See 'Treat the underlying disorder' above.)

●Restoration of airway patency to alleviate symptoms. (See 'Restore airway patency' below.)

While bronchoscopic local therapy is the most common initial therapy, a multimodal approach is often necessary so that these goals can be achieved. For example, treatment of subglottic stenosis may need anti-inflammatory agents as well as local ablative therapies while patients with complex or multiple tracheal stenoses may need local bronchoscopic therapy for one or more lesions and surgery for another lesion.

Restore airway patency — Restoring airway patency typically requires local bronchoscopic therapy and/or surgery. The goal of restoring airway patency is the alleviation of symptoms and avoidance of critical airway stenosis in the future.

●In practice many stenoses are not amenable to surgery such that local bronchoscopic therapies, administered alone or in combination, are the main initial tools used to restore airway patency and achieve symptom alleviation (eg, dilation, electrocautery, laser, cryotherapy, stents). (See 'Initial therapy: Bronchoscopy' below.)

●However, in rare circumstances, the stenosis may be too complex for local therapy and a direct surgical approach may be needed (eg, stenosis with malacia component, vascular stenosis or complications of previous tracheal reconstruction). (See 'Surgery' below.)

Initial therapy: Bronchoscopy — In patients with non-life-threatening, nonmalignant subglottic stenosis and TS, bronchoscopy is most often the first-line therapy administered to restore airway patency. The rationale is that bronchoscopy is a minimally invasive procedure that carries less risk when compared with major tracheal surgery and is much more widely available than centers of airway surgery expertise.

In many patients, both diagnostic and therapeutic bronchoscopy are combined at initial presentation (eg, biopsy and balloon dilation during the same session). Depending on the biopsy results and response to bronchoscopic therapy, additional therapies can be administered, often necessitating a second procedure. (See "Presentation and diagnostic evaluation of non-life-threatening and nonmalignant subglottic and tracheal stenosis in adults", section on 'Bronchoscopic evaluation'.)

Choosing among the procedures — Procedures commonly used to restore airway patency include the following:

●Balloon dilation. (See "Flexible bronchoscopy balloon dilation for nonmalignant airway strictures (bronchoplasty)".)

●Stent placement. (See "Airway stents".)

●Ablative/"cutting" procedures, such as electrocautery, laser, or cryotherapy. (See "Endobronchial electrocautery" and "Bronchoscopic laser in the management of airway disease in adults" and "Bronchoscopic cryotechniques in adults".)

●Flexible bronchoscopy with removal of foreign body, broncholith, or pseudomembranes. (See "Airway foreign bodies in adults".)

Choosing among these options is often at the discretion of the operator and dependent upon stenosis location, disease extent, the underlying etiology, and available technologies. Some general principles include the following:

●Patients with short and simple lesions may have a better response to local bronchoscopic therapies than longer more complex lesions (table 1). An example of such a lesion includes a single web-like lesion that is <1 cm in length and >1 cm below the cricoid cartilage and does not have associated cartilage damage or tracheomalacia.

●In patients with more complex stenoses, bronchoscopic procedures are typically less effective than surgery but remain useful for airway stabilization prior to surgery or for palliation in patients who are not suitable for surgery [1]. Associated tracheomalacia is generally treated with either silicone stenting or surgery. (See "Airway stents" and "Tracheomalacia in adults: Treatment and prognosis", section on 'Stent trial'.)

●Many stenoses are initially dilated, sometimes in combination with local ablation (eg, two to three radial incisions) and/or stenting (image 1 and image 2). Ablative techniques are used sparingly to avoid extensive damage of airway mucosa that may induce an exuberant fibrotic response and actually increase the risk of recurrence and worsen the stenosis. Exceptions include patients with recurrent papillomatosis and tracheobronchopathia osteochondroplastica where extensive debulking of intraluminal lesions may be needed. (See 'Infectious etiologies' below and 'Tracheobronchopathia osteochondroplastica' below.)

●In cases of complex stenosis, local bronchoscopic therapy may be combined with surgery. For example, in patients with multiple stenoses, one lesion may be responsive to bronchoscopic balloon dilation and/or ablation but a second lesion may require surgery or pretreatment with local bronchoscopic therapy prior to surgery.

Follow-up — After any procedure, patients should be followed closely at centers of expertise for complications of the procedure(s) performed, for the symptomatic response to the procedure, and for recurrence. We evaluate patients within two to four weeks after the procedure and then follow every one to three months until symptoms return or stability is achieved.

There is no standard approach to surveillance, but we typically inquire about recurrent symptoms at every visit and have a low threshold to perform a chest or dedicated airway CT and bronchoscopy when recurrent symptoms are suggested. For example, patients who undergo local bronchoscopic dilation and/or ablative therapy should be evaluated within two to four weeks after the procedure(s) and then followed every one to three months until symptoms return or stability is achieved. (See "Presentation and diagnostic evaluation of non-life-threatening and nonmalignant subglottic and tracheal stenosis in adults".)

Efficacy — Data to support the use of bronchoscopic therapies are limited. As examples:

●One series of 92 balloon dilation procedures performed in 35 patients with TS, 11 of whom had endotracheal or tracheostomy tube-related stenosis and 14 of whom had post-lung transplant TS, bronchial balloon dilation resulted in improved airway diameter, symptoms, and spirometry [2]. However, the effect was temporary, and 71 percent eventually required stent placement for recurrence at an average of 210 days after the procedure. Patients with fixed stenosis were more responsive to simple balloon dilation (ie, fibrotic stenosis without any component of cartilage, malacia and without dynamic features) [2,3].

●In a series of 115 patients with postintubation TS, recurrence following interventional bronchoscopy was seen in 25 percent of cases [4]. Ultimately, tracheal stent placement was required in 19 percent, especially in those with complex strictures, and surgical intervention occurred in 30 percent of patients. Long-term recurrence was seen in a significant number of those following stent removal.

RECURRENCE — Recurrence is common following local bronchoscopic therapy, although rates vary depending on the stenosis characteristics and etiology (range 25 to 71 percent) [2-4]. There are no proven predictors for recurrence, but in our experience, simple stenoses and stenoses with a reversible underlying etiology (eg, viral infection, autoimmune inflammation, short web-like stenoses) are less likely to recur than complex or fibrotic stenoses that are without a reversible etiology.

Repeat local bronchoscopic therapy — For the majority of patients with recurrence, we repeat the local bronchoscopic procedure. In general, most patients require more than one local bronchoscopic therapy over the course of their lifetime and may need several repeat procedures for recurrence and long-term benefit (eg, one to two per year).

Choosing among the procedures is individualized, and the principles are similar to that described above (see 'Choosing among the procedures' above). However, additional therapies are often combined with bronchoscopic intervention. For example, if balloon dilation was performed previously, the stenosis may be dilated again and combined with radial mucosal-sparing laser incisions or stent placement to maintain patency for a longer period of time (image 3). As an alternative, some experts may inject the lesion with corticosteroids or apply mitomycin C at the end of the bronchoscopic procedure to reduce the chances of recurrence, but the impact of such therapy is considered controversial with limited data to support it [5,6]. (See 'Initial therapy: Bronchoscopy' above.)

There is no consensus regarding how many bronchoscopic dilation or ablation procedures should be performed or what the optimal length of time for recurrence is prior to evaluation for surgery. It is crucial to avoid repeated use of airway stenting with dilation since this can potentially convert a patient who is potentially 'curable' by surgery to a non-surgical candidate due to iatrogenic lengthening of the underlying stenosis. Indications for surgery are discussed below. (See 'Surgery' below.)

A newer endoscopic resection technique may be trialed in some patients as an alternative to mucosal sparing laser incisions with balloon dilation. Three to four laser wedge excisions are performed leaving bridges to prevent scar formation. Endoscopic resection can be combined with medical therapy including anti-acid reflux therapy, inhaled corticosteroids and trimethoprim-sulbactam, although the benefits of this approach are unclear [7].

Surgery

●Indications – Tracheal or subglottic surgery is generally considered a second-line therapy, which is reserved for the following patients, provided they have suitable anatomy and no comorbidities that preclude surgical intervention:

•Patients who recur quickly despite one or more local bronchoscopic therapies (eg, a few weeks after a first or second local therapy)

•Patients who have an etiology unlikely to reverse with systemic therapy (eg, fibrotic scar).

•Patients with complex lesions not suitable for local therapy (table 1).

Although poorly documented, in our experience, up to 20 percent of patients, require surgery. The goals of tracheal surgery are curative and elimination of the need for repeat bronchoscopic interventions. Success rates are highest when appropriate patients are selected for surgery. Stenoses that are considered more favorable for surgical success include short segment of stenosis, lesions that are further away from the vocal cords or glottis, and noninflammatory lesions.

The decision to undergo tracheal surgery is challenging since the surgery itself is technically difficult, has a moderate complication rate, and is not universally available. Factors involved in the decision to proceed with surgery include the following:

•Lesion characteristics (eg, length, severity, complexity, location, distance from and involvement of the cricoid cartilage, distance from the carina, concurrent tracheomalacia (table 1))

•Response to initial bronchoscopic therapy and degree of recurrence

•Patient prognosis or health status/comorbidities

•Etiology of the lesion

•Predicted response to surgery

•Available expertise and operator experience

•Patient preference

●Efficacy – Data describing outcome with surgery are limited. In general, surgical treatment has a high success rate when appropriate patients are selected and operated on by an experienced team.

•In the largest published series of 901 patients, 95 percent had a good result with an overall complication rate of 18 percent [8]. Approximately 4 percent of patients required a long-term artificial airway tube. The overall mortality rate was 1.4 percent. The presence of diabetes and treatment with corticosteroids were associated with increased complications and poor wound healing. Anastomotic complications increased with longer segments of resection. In another retrospective study of 267 patients with similar results, 38 percent had at least one complication and only those with complications developed restenosis [9].

•In another study of 392 patients, operative mortality was <1 percent [10]. Over 95 percent of patients had improved symptoms and airway dimensions, provided resection was limited to the trachea and did not involve the larynx. However, the complication rate was high (18 to 25 percent), particularly for anastomotic dehiscence, the risk of which was increased when longer lengths of trachea were resected.

●Surgical techniques – There are several surgical approaches. Choosing one is dependent upon the stenosis characteristics and expertise of the operating surgeon.

•Tracheal resection with simple end-to-end anastomosis (simple lesions/webs, stenoses not involving the cricoid cartilage) – The trachea is exposed and then transected using circumferential transverse incisions through the upper and lower borders of the stenosis. The stenotic segment is excised. The distal trachea is mobilized from surrounding structures in order to approximate the edges and provide tension-free anastomosis. The maximum length that can be resected varies with the patient's anatomy but in general is approximately 4 cm. For resection of longer segments, a number of techniques are used to release or mobilize the trachea, including hyoid bone release and hilar and pericardial release techniques. (See "Presentation and diagnostic evaluation of non-life-threatening and nonmalignant subglottic and tracheal stenosis in adults", section on 'Normal anatomy and tracheal dimensions'.)

Tracheal resection has a high success rate with low mortality when performed in experienced centers. Complications are uncommon and include temporary/permanent tracheostomy or T-tube placement, anastomotic complication leading to reintervention (repeated dilations, appliance, reoperation), increased hospital length of stay, and death.

Predictors of success are poorly studied. A multivariate analysis of 901 patients who underwent tracheal resection revealed the following predictors of anastomotic complications [8]:

-Reoperation (odds ratio [OR] 3.03)

-Diabetes (OR 3.32)

-Resection length ≥4 cm (OR 2.01)

-Age ≤17 years (OR 2.26)

-Need for tracheostomy before operation (OR 1.79)

Another study revealed the below risks for restenosis in an analysis of 34 patients who underwent tracheal resection (not involving the cricoid cartilage) [11]:

-Diameter of stenosis

-Distance between cricoid cartilage and stenosis

-Smoking

-Grade of stenosis were all significantly associated with restenosis

•Cricotracheal resection (eg, for subglottic stenosis or high TS involving the cricoid) – Cricotracheal resection is a surgical procedure for treatment of severe subglottic stenosis or congenital TS involving the subglottic space (with or without glottic space involvement). Operative techniques vary depending on whether there is glottic involvement/pathology. For patients with subglottic stenosis, resection requires partial excision of the cricoid cartilage. In cases with glottic involvement, extensive cricotracheal resection with cartilage grafting is generally performed in a staged fashion [12]. Surgery involving the cricoid is more complex and has been associated with increased risk of anastomotic complications [8].

•Laryngotracheal resection with end-to-end anastomosis (eg, for lesions involving the subglottic space) – This surgery can be more complicated as it may involve resection of the cricoid ring or even part of the thyroid cartilage [13].

•Slide tracheoplasty (eg, for congenital TS, long-segment TS, complete tracheal rings) – Cases of congenital tracheal stenosis, including long-segment TS (LSTS; >50 percent length of trachea), can be managed by the surgical procedure "slide tracheoplasty." In this surgery, the narrowed trachea is divided across the middle of the stenosis, with incisions made on the back and lower tracheal segment as well as on the front of the upper trachea. The opened ends then slide onto each other and are sutured in place to create an airway that is twice as wide and half as long. It has subsequently been adapted to treat other conditions, such as laryngotracheal stenosis, tracheoesophageal fistula, and bronchial stenosis [14].

Slide tracheoplasty has emerged as the preferred surgical treatment for LSTS due to improved efficiency, lower rates of postoperative and long-term complications, reduced perioperative cost, and lower mortality compared with other procedures [15].

•Augmentation tracheoplasty (eg, for stenoses not amenable to end-to-end techniques) – This involves tracheal resection and use of cartilaginous grafts and muscle flaps.

•Investigational tracheal reconstruction techniques – Several newer minimally invasive tracheal reconstruction techniques have been described with low complication but are restricted for use in the small number of centers with expertise. Further experience and data are required before they can be routinely recommended.

-"Maddern" procedure – This technique has been described for treating isolated subglottic stenosis. It is a surgical option for patients with short dilation intervals who prefer to avoid the risks of cricotracheal resection [16,17]. Through an endoscopic approach, the stenosis is completely removed with a soft-tissue shaver. The cricoid is relined with a buccal or skin graft and held in place by a temporary silicone stent. This technique is minimally invasive, has the potential to preserve voice function, and may result in a curative outcome with durable physiologic improvement in peak expiratory flow rate. Preliminary evidence suggests that with good patient selection this procedure can be successful with a low complication rate in most patients, especially in those with stenosis involving the upper rather than lower subglottis [17].

-"REACHER" procedure – A retrograde endoscopically assisted cricoid hypertrophic epithelial resection (REACHER) procedure is aimed at removing the diseased mucosa and leaving the cartilage framework intact. This technique uses a minimally invasive open approach to excise the mucosa and a skin graft to modulate the wound healing response [18]. This procedure is performed through a neck incision where an opening in the airway is made right below the cricoid to access the cricoid lumen. Endoscopes are used to assist in complete resection of the involved mucosa and laminal propria. A silicone stent wrapped in a nonadherent dressing and then a skin graft is then placed.

●Complications – Complications include bleeding, wound infection, anastomotic dehiscence, need for tracheostomy, recurrence of the stenosis, tracheomalacia, and tracheoesophageal and tracheoinnominate artery fistula formation [10,19]. For those who have subglottic surgery, additional complications include glottic edema, granulation tissue, and lower voice pitch [20].

●Follow-up – Following surgery, patients are managed as inpatients. Some patients need to undergo tracheostomy care and decannulation due to pre-existing tracheostomy tubes (eg, those with severe subglottic stenosis) or extensive surgery. Follow-up thereafter occurs as an outpatient similar to that described for patients who have undergone local bronchoscopic therapy. (See "Tracheostomy: Postoperative care, maintenance, and complications in adults" and 'Initial therapy: Bronchoscopy' above.)

REFRACTORY DISEASE

Tracheostomy or T-tube — For patients who fail local bronchoscopic therapy or surgery, are not good candidates for surgery, or need a bridge to surgery, a tracheostomy, T-tube, or tracheotomy may be the only option. In our experience, only a small proportion of patients need such therapies (eg, <5 percent).

●A tracheostomy tube is placed into the trachea through a stoma at the neck and relieves symptoms by placement below or across the stenosis. A tracheotomy is a direct connection between the skin of the neck and the trachea itself. Rarely, the trachea can be brought to the skin of the chest wall through the sternum. A tracheotomy bypasses the stenosis by resecting the trachea below the level of the stenotic lesion. (See "Tracheostomy: Rationale, indications, and contraindications" and "Tracheostomy in adults: Techniques and intraoperative complications".)

●A T-tube is a silicone tracheal stent that is placed through the TS and connects to the skin of the neck through a tracheostomy stoma (ie, functions like a stent and a tracheostomy tube (figure 3)). Unlike a "free" stent that is placed in the airway with no or little mechanism of anchoring to the airway wall and has potential to migrate, a T-tube is "anchored" and does not migrate by virtue of a horizontal limb that extends through the stoma. This can be a permanent solution for some patients who do not have other options (image 4). One concern regarding T-tubes is a lack of familiarity with the device by most health care providers and lack of knowledge of how to manage the tube in emergent situations.

There are no high-quality data that describe the outcome in association with tracheostomy or T-tubes in patients with TS. Patients and clinicians should be aware that tracheostomy and T-Tube also carry the risk of device-associated stenosis.

MANAGEMENT OF STENOSIS DUE TO SPECIFIC ETIOLOGIES — Described in this section is our approach to therapy for individual etiologies associated with symptomatic non-life-threatening, nonmalignant subglottic stenosis and TS (table 2).

Traumatic — Postintubation TS (PITS) or posttracheostomy TS (PTTS) are the most common forms of TS seen in practice. Intubation- or tracheostomy-related subglottic stenosis is less common but can occur.

●TS – In most cases, tracheal stenoses in this population are circumferential fibrotic strictures and are often managed through a combination of dilation (eg, dilating balloons, rigid dilators, or the rigid bronchoscope itself) and thermal techniques (eg, two to three radial incisions through fibrous tissue with laser or electrocautery knife) or stenting (eg, associated tracheomalacia) (table 2 and image 3). When balloon dilation is used alone, recurrence is common (eg, 25 to 70 percent of patients), such that combination therapy is generally needed. (See 'Initial therapy: Bronchoscopy' above and "Flexible bronchoscopy balloon dilation for nonmalignant airway strictures (bronchoplasty)" and "Bronchoscopic laser in the management of airway disease in adults" and "Endobronchial electrocautery".)

For patients who develop recurrent stenosis, repeat bronchoscopic procedures are often required before referring for surgery. Other techniques such as bronchoscopic corticosteroid injection or mitomycin topical application have also been used [21]. (See 'Recurrence' above.)

Refractory cases, patients who need a bridge to surgery, and patients who are not suited to surgery may be evaluated for a tracheostomy or T tube. (See 'Refractory disease' above.)

Other types of traumatic stenoses that have resulted in a fibrotic stricture, such as that resulting from a foreign body, external trauma, or an inhalational event (table 2), are typically managed using similar local bronchoscopic tools.

Bronchoscopic application of spray cryotherapy remains investigational. (See "Bronchoscopic cryotechniques in adults".)

●Subglottic stenosis – Management of subglottic stenosis due to trauma is similar to that described for patients with idiopathic subglottic stenosis (ISGS), which is discussed below. (See 'Idiopathic subglottic stenosis' below.)

Inflammatory/systemic etiologies — For most patients with inflammatory causes of subglottic stenosis or TS (table 2), we suggest systemic treatment for the underlying disease (see 'Treat the underlying disorder' above). In addition, for patients with severe stenosis (eg, >50 percent luminal narrowing) or in patients who do not respond to systemic pharmacologic therapy, we suggest the application of local bronchoscopic therapies (eg, dilation, ablation, and/or stenting). In patients with recurrent stenosis or stenosis that is resistant to therapy, repeat bronchoscopic dilation/ablation/stent therapies and/or bronchoscopic injections of corticosteroids or topical application of mitomycin C may be tried. Surgery or tracheostomy may be the only option in patients with recurrent disease despite this approach. (See 'Symptomatic patients' above.)

●Systemic therapy targeted at inflammation – Systemic therapies for these disorders are provided separately:

•Granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (see "Granulomatosis with polyangiitis and microscopic polyangiitis: Induction and maintenance therapy" and "Granulomatosis with polyangiitis and microscopic polyangiitis: Management of relapsing disease" and "Granulomatosis with polyangiitis and microscopic polyangiitis: Management of disease resistant to initial therapy")

•Eosinophilic GPA (see "Eosinophilic granulomatosis with polyangiitis (Churg-Strauss): Treatment and prognosis")

•Rheumatoid arthritis (see "General principles and overview of management of rheumatoid arthritis in adults" and "Overview of pleuropulmonary diseases associated with rheumatoid arthritis", section on 'Upper airway obstruction')

•Sarcoidosis (see "Treatment of pulmonary sarcoidosis: Initial approach" and "Treatment of pulmonary sarcoidosis refractory to initial therapy")

•Relapsing polychondritis (see "Treatment of relapsing polychondritis")

•Behçet syndrome (see "Treatment of Behçet syndrome")

•Inflammatory bowel disease (see "Sulfasalazine and 5-aminosalicylates in the treatment of inflammatory bowel disease" and "Overview of budesonide therapy for adults with inflammatory bowel disease" and "Treatment of arthritis associated with inflammatory bowel disease" and "Medical management of moderate to severe Crohn disease in adults")

•Immunoglobin G-4-related disease (IgG4-RD) (image 2) (see "Treatment and prognosis of IgG4-related disease")

•Systemic lupus erythematosus (see "Pulmonary manifestations of systemic lupus erythematosus in adults")

●Local bronchoscopic techniques – There is no standard bronchoscopic approach for inflammatory conditions since they are rare causes of stenosis. In patients with inflammatory mucosal stenosis or cicatricial fibrotic lesions, we use balloon dilation alone or in combination with thermal techniques, such as electrocautery or laser, to treat focal areas of stenosis [22-26]. (See 'Initial therapy: Bronchoscopy' above.)

In more severe cases resulting in chondritis and cartilaginous destruction, such as in relapsing polychondritis, there may be a need for airway stenting due to associated tracheomalacia (image 1) [27]. When a stent is used, silicone stents are usually preferred due to the long-term adverse consequences of self-expandable metallic airway stents that can occur in benign disease. (See "Airway stents", section on 'Silicone stents'.)

Only case reports have described some success with bronchoscopic injections of corticosteroids and topical application of mitomycin C in conjunction with local ablation or dilation in patients with inflammatory airway stenoses [26,28,29]. In our experience, one to two repeat injections may delay, but not prevent recurrence.

●Surgery or tracheostomy – In truly resistant cases, surgical reconstruction or tracheostomy may be the only options. In our experience, this scenario most likely occurs in patients with GPA due to the predilection of GPA to affect the subglottis. (See 'Refractory disease' above.)

Infectious etiologies — In patients with infectious subglottic stenosis or TS, airway narrowing can be due to inflammation or pseudomembrane formation and later during the course, fibrosis.

●For patients with acute infectious stenosis with or without pseudomembrane formation (image 5), we treat the underlying infection with appropriate antimicrobial therapy. The rationale for this approach is that most patients are likely to respond to antimicrobial therapy without developing stenosis long term.

In some cases, pseudomembranes can be bronchoscopically removed to additionally improve airway patency. A large pseudomembrane is best mechanically removed with a rigid bronchoscope with or without use of large biopsy forceps. In less severe cases, this can also be performed with flexible bronchoscopy using biopsy forceps or cryoprobe techniques.

●Even in cases of appropriate therapy, some patients, particularly those with endobronchial tuberculosis (TB), may go on to develop fibrotic airway stenosis. In patients with endobronchial TB, it is unclear whether the airway should be periodically monitored (eg, with chest CT or bronchoscopy) during systemic therapy for evolving or resolving stenosis. Once fibrotic cicatricial stenosis develops, we apply the same principle to therapy as that in patients with PITS/PTTS. (See 'Traumatic' above.)

One infection requiring specific mention is recurrent respiratory papillomatosis (RRP) where debulking is the focus of management. There is no cure.

●Local debulking therapy – When RRP occurs in the trachea (or bronchi), the mechanism of stenosis is usually due to bulky papillomatous growth rather than a focal stricture or stenosis. Thus, airway-specific therapy is usually focused on debulking techniques, such as flexible or rigid bronchoscopy with mechanical debulking using a forceps or a microdebrider, or thermal ablative therapy, such as laser or electrocautery. Success from direct lesional injection with cidofovir and photodynamic therapy is limited to case reports [30-32]. (See 'Initial therapy: Bronchoscopy' above and "Bronchoscopic laser in the management of airway disease in adults" and "Endobronchial photodynamic therapy in the management of airway disease in adults" and "Bronchoscopic argon plasma coagulation in the management of airway disease in adults".)

●Systemic therapy – Approximately 20 percent of patients receive adjunct systemic medical therapies in addition to endobronchial therapy to control RRP. Systemic therapies include interferon gamma, cidofovir, indole-3-carbinol, celecoxib, bevacizumab, and human papillomavirus vaccine [33-35]. However, experience is limited and clinician-dependent. (See "Human papillomavirus infections: Epidemiology and disease associations" and "Human papillomavirus vaccination".)

●Surgery or tracheostomy – Surgery or tracheostomy may be needed for recurrent or resistant cases.

Tracheobronchopathia osteochondroplastica — In severe and symptomatic cases, tracheobronchopathia osteochondroplastica (TPO) requires bronchoscopic intervention with laser therapy and mechanical removal of parts of the stenosis through rigid bronchoscopy [36]. This primarily involves physical debulking of the cartilaginous growths and may need to be repeated. These patients may also require airway stenting. (See 'Initial therapy: Bronchoscopy' above and "Airway stents".)

Nonmalignant tumors — The principles of bronchoscopic techniques for nonmalignant tumors are similar to that in patients with endobronchial malignant airway tumors. In brief, stenosis due to nonmalignant tumors may be amenable to local bronchoscopic therapy, such as electrocautery, laser, argon plasma coagulation, or cryotherapy. Some benign tracheobronchial tumors can achieve cure with bronchoscopic techniques. (See "Clinical presentation, diagnostic evaluation, and management of malignant central airway obstruction in adults", section on 'Bronchoscopic ablative therapies' and 'Initial therapy: Bronchoscopy' above and 'Recurrence' above.)

The only exception is if the diagnosis is uncertain and carcinoid is suspected, then surgery may be preferred as the initial step. Failing local therapies may also necessitate surgical resection or tracheal reconstruction, provided the lesion is suitable. (See 'Surgery' above and 'Refractory disease' above.)

Other — Other causes of subglottic stenosis or TS are discussed below:

●Amyloidosis – Treatment options for symptomatic amyloidosis-related stenosis include recanalization with local bronchoscopic therapies and mucosal sparing laser incisions, and rarely, external beam radiation (image 6); balloon dilation and stents are generally bridge therapies towards tissue removal [37-40]. Further details are provided separately. (See 'Initial therapy: Bronchoscopy' above and "Pleuropulmonary manifestations of amyloidosis", section on 'Management'.)

Systemic drug therapy is not necessarily needed for primary tracheobronchial amyloidosis but may be needed for patients with secondary amyloidosis.

Treatment of tracheobronchial amyloidosis and systemic therapies for amyloidosis are discussed separately. (See "Overview of amyloidosis", section on 'Treatment' and "Treatment of AA (secondary) amyloidosis" and "Treatment and prognosis of immunoglobulin light chain (AL) amyloidosis".)

●Mucus membrane pemphigoid – Treatment is focused on prevention of scarring and primarily involves systemic therapy for acute lesions (eg, systemic corticosteroids and doxycycline) [41]. (See "Management and prognosis of bullous pemphigoid".)

For patients with fibrotic scar from recurrent flares, an approach similar to that in patients with PITS is reasonable and includes balloon dilation, lesional injection with corticosteroids, and stent placement However, surgery can be challenging as the tissue is prone to re-scarring and decreased healing. Tracheostomy is rarely needed.

●Radiation – Management of radiation-induced tracheobronchial stenosis can be difficult. Lesions are more common in bronchi than trachea and therefore, less amenable to local bronchoscopic management. Based on location and extent, strategies are preferentially given to bronchoscopic interventions, such as dilation and stent placement, and to tracheostomy. There is only a limited role for laser or other ablative therapies since the mucosa is often friable and prone to bleeding with intervention but may be more useful if the lesion is fibrotic (See 'Initial therapy: Bronchoscopy' above.)

Surgical intervention can be challenging and complicated by friability and bleeding due to mucosal inflammation (during the earlier phase) and to anatomical distortion during the chronic fibrotic phase [42]. (See 'Recurrence' above.)

●Extrinsic compression – The mainstay of therapy for patients with disease external to the trachea causing compressive stenosis is treatment of the underlying cause. Stenting may be a temporary solution while a response to therapy for the underlying disorder is awaited. (See 'Treat the underlying disorder' above and "Airway stents".)

●Fibrosing mediastinitis – The treatment of tracheobronchial stenoses due to fibrosing mediastinitis targets symptom improvement with balloon dilation and stent placement with a limited role, if any, for laser or other ablative therapies. Anti-inflammatories may be tried in patients with mediastinal fibrosis due to an autoimmune disorder or IgG4-RD or in patients with idiopathic disease. Surgery can be fraught with complications due to anatomical distortion and is reserved for resistant cases. Tracheostomy may be an option, depending on the location and severity of the stenosis. Further details are provided separately. (See "Mediastinal granuloma and fibrosing mediastinitis", section on 'Treatment'.)

●Broncholiths – Broncholithiasis rarely causes primary tracheal narrowing and is more likely to cause lobar or segmental bronchial stenosis (image 7).

Intraluminal broncholiths that are not attached to the airway wall may be expectorated spontaneously or can be bronchoscopically extracted using forceps, snares, or laser lithotripsy. (See "Airway foreign bodies in adults", section on 'Foreign body removal'.)

Extraluminal broncholiths that are almost entirely outside the airway may be followed clinically unless severe symptoms, such as refractory cough or bleeding, occurs. In the latter scenario, extraluminal lesions may require a thoracic surgical approach for removal.

Mixed intra/extraluminal broncholiths present challenges for management. Bronchoscopic removal, typically with laser (eg, Holmium, KTP, Nd:YAG) can be successful, however, there is increased risk of perforation, fatal hemorrhage, and fistula formation [43]. (See 'Initial therapy: Bronchoscopy' above.)

●Congenital – Treatment of stenoses due to congenital conditions depends upon the etiology. For example, webs may be subjected to dilation while laryngoceles may need microlaryngoscopic resection using carbon dioxide laser or robotic surgery [44,45]. These lesions including others such as vascular rings uncommonly present in adulthood and may require tracheal or vascular surgery.

Idiopathic subglottic stenosis — There is no known systemic therapy for patients with ISGS. While some patients with "simple" concentric web-like stenosis may be treated with therapeutic bronchoscopy, those with complex or refractory lesions will likely require a multimodality approach or surgical correction (image 8).

●General – Many clinicians administer empiric gastroesophageal reflux disease treatment. Practice varies widely with no consensus on a preferred medication or duration of therapy. We typically treat empirically in more severe cases of stenosis with frequent recurrence. This usually consists of a proton-pump inhibitor at a low to medium dose.

For recurrent cases, some experts administer antireflux therapy in combination with oral trimethoprim/sulfamethoxazole and inhaled corticosteroids based upon observational data that suggest a possible reduction in the rate of recurrence [46].

●Initial therapy: Local bronchoscopic therapy – As first-line therapy, a wide variety of local bronchoscopic techniques have been utilized. (See 'Initial therapy: Bronchoscopy' above.)

•We typically perform lesion incision using a "mucosal sparing technique", involving one to three radial mucosal incisions with a laser or cautery device followed by gentle balloon dilation (image 8) [47,48]. Complete mucosal ablation of the stenosis is avoided since it promotes recurrent scarring and poor long-term patency.

•Airway stent placement is rarely done due to the proximal location and difficulty placing stents close to the vocal cords or in the conus elasticus.

•Injectable corticosteroids have been used. In one retrospective study of 49 patients, most of whom had idiopathic subglottic or proximal airway stenosis, serial in-office corticosteroid injections following endoscopic dilation improved the interval between procedures from 13.5 months (prior to using serial injections) to 42 months (following the serial injection program) [49]. Their protocol consisted of three to six in-office injections every three to six weeks after dilation and had potential cost-savings.

Bronchoscopic techniques typically result in significant improvement in symptoms, although most patients experience recurrence.

●Recurrent disease: Repeat bronchoscopy and/or surgical resection – Due to the fibroinflammatory nature of this condition, with frequent recurrence, patients typically require repeat and combination local bronchoscopic therapy over a long period of time. However, the pattern and frequency of recurrence varies widely. Procedures may also be combined with intralesional corticosteroid or mitomycin C application, although the value is unclear [5,6].

For patients who are not responsive or recur rapidly following bronchoscopic therapy, we evaluate their suitability for surgery. Approximately 20 percent of patients with ISGS undergo surgery [50]. The surgery is particularly difficult due to factors such as proximity to the vocal cords and cricoid cartilage, which prohibit extensive resection and reconstruction and can affect voice pitch. In addition, there is variable practice and technical skill among surgeons and limited clinical experience since it is a relatively infrequent condition.

There are multiple surgical techniques described for managing patients with ISGS. These include the following [51,52] (see 'Surgery' above):

•Laryngoplasty (laryngeal dilation) with cartilage graft.

•Laryngotracheal resection with anastomotic reconstruction and T-tube placement.

•Tracheal reconstruction using the "Maddern" or "REACHER" techniques.

Laryngotracheal resection is more definitive but only suitable for those with short or simple lesions while laryngoplasty may be the only option in those with extensive lesions. Tracheostomy decannulation rates are as high as 80 percent (laryngoplasty) or 95 percent (resection). Choosing among these depends upon the surgeon, their skill, the lesion characteristics, and patient candidacy.

●Refractory disease – Rarely, for patients with refractory subglottic stenosis and for patients who are not surgical candidates and fail local therapy, tracheostomy or a T-tube may be utilized. (See 'Refractory disease' above.)

Data to support this approach are limited [20,51,53,54]:

●In one meta-analysis of 24 retrospective studies of patients with ISGS, pooled success rates (defined as the condition not requiring further treatment) were 95 percent for laryngotracheal resection and anastomosis and 76 percent for laryngoplasty with or without grafting [51]. Success rates of bronchoscopic therapy ranged from 40 to 82 percent, with the highest success in patients with simple lesions (eg, lesion length <1 cm without framework destruction) compared with more complex lesions (eg, stenosis length of >1 cm) (80 versus 47 percent).

●In a subsequent comparative outcome study, 810 patients with ISGS were prospectively followed after undergoing cricotracheal resection, bronchoscopic resection with adjuvant medical therapy (eg, laser with mitomycin C), or bronchoscopic dilation [54]. During this three-year study, the need for a recurrent surgical procedure was 1.2 percent for cricotracheal resection, 12.4 percent for endoscopic resection with adjuvant medical therapy, and 28 percent for endoscopic dilatation. Although cricotracheal resection demonstrated the best results, it was achieved at the expense of significant adverse effects, including a need for tracheostomy, repeat surgery, vocal cord paralysis, anastomotic leak, postoperative infection, and lower voice pitch.

●In another retrospective study, factors associated with recurrence after surgical repair were prior stents, postoperative edema, mitomycin use, and vocal cord involvement [53].

OTHER NOVEL TRACHEAL TECHNIQUES — There are many novel interventions undergoing investigation including tracheal transplantation and other forms of replacement including synthetic prostheses, allografts from other tissue, autologous tracheal replacement using other tissue, and bioengineering utilizing stem cells. All of these techniques have been limited to case reports or series [55-57]. As an example, one series that utilized forearm free flap and autologous cartilage tracheal construction reported a 65 percent five-year survival rate without the need for airway stent placement [55].

SUMMARY AND RECOMMENDATIONS

●Scope – This review will focus on the management of adults with nonmalignant, non-life-threatening stenosis at any level between the subglottis and the main carina of the trachea (figure 1). Data to support specific therapies are limited, and therapeutic strategies described in this topic are representative of our practice. (See 'Terminology and scope' above and 'General principles of the approach' above.)

●Referral and treat the underlying disorder – Patients with non-life-threatening, nonmalignant subglottic stenosis or tracheal stenosis (TS) should be referred to a center of expertise in therapeutic bronchoscopy and/or airway surgery. If feasible, we treat the underlying disorder systemically (Grade 2C). For some patients, this may be sufficient and result in symptomatic improvement (eg, stenosis due to acute inflammation) while for others, the stenosis may be unresponsive (eg, old fibrotic stenosis). (See 'General principles of the approach' above.)

●Asymptomatic patients – For most patients who are asymptomatic, we suggest an initial period of observation rather than a specific intervention for the stenosis itself (Grade 2C). The rationale for observation is based upon our experience and the avoidance of a potentially unnecessary procedure. (See 'Asymptomatic patients' above.)

•Exceptions – Exceptions include patients with severe stenosis (eg, >75 percent stenosis or <5 mm cross sectional diameter), patients who have developed complications (eg, significant hemoptysis or mucus impaction), or patients with stenosis that is likely to be problematic in the future (eg, expected problems during future intubation or decannulation). (See 'Treat the underlying disorder' above and 'Observation' above.)

•Observation – We periodically follow patients every 6 to 12 months using clinical history and examination and pulmonary function testing (PFT; specifically flow volume loop assessment). If patients develop symptoms or worsening PFTs, we perform chest and neck CT and bronchoscopy to reassess the degree of stenosis. (See 'Observation' above.)

●Symptomatic patients – For most patients who are symptomatic, we suggest initially restoring airway patency using local bronchoscopic intervention rather than observation or surgical intervention (Grade 2C). The rationale is that bronchoscopy is a minimally invasive procedure that improves symptoms in most patients and is less invasive than major tracheal surgery (image 3 and image 8); in addition, it is much more widely available than centers of airway surgery expertise. (See 'Symptomatic patients' above and 'Restore airway patency' above and 'Initial therapy: Bronchoscopy' above.)

•Local bronchoscopic procedure – Options include any one or more the following:

-Balloon dilation. (See "Flexible bronchoscopy balloon dilation for nonmalignant airway strictures (bronchoplasty)".)

-Stent placement. (See "Airway stents".)

-Ablative/"cutting" procedures such as electrocautery, laser, or cryotherapy. (See "Endobronchial electrocautery" and "Bronchoscopic laser in the management of airway disease in adults" and "Bronchoscopic cryotechniques in adults".)

-Flexible bronchoscopy with removal of foreign body, broncholith, or pseudomembranes. (See "Airway foreign bodies in adults".)

Choosing among these options is often at the discretion of the operator and dependent upon stenosis location, disease extent, the underlying etiology, and available technologies. In most cases, balloon dilation is the most common initial bronchoscopic procedure used for symptomatic relief. (See 'Choosing among the procedures' above.)

•Follow-up – We evaluate patients within two to four weeks after the procedure and then follow every one to three months until symptoms return or stability is achieved. (See 'Follow-up' above.)

●Recurrence – Recurrence rates are generally high (range 25 to 71 percent), although the frequency of recurrence and duration of response varies.

•For those with recurrent disease, we suggest repeat local bronchoscopic therapy combined with additional bronchoscopic or medical therapy (eg, electrocautery incision, stent, corticosteroid injection) (Grade 2C). (See 'Repeat local bronchoscopic therapy' above.)

•For patients who recur quickly (eg, a few weeks after a first or second local therapy) or for patients who have an etiology unlikely to reverse with systemic therapy or have a complex lesion not suitable for local therapy (table 1), we refer for surgical evaluation. In general, surgical treatment has a high success rate when appropriate patients are selected, but complications are frequent (up to 25 percent). Conditions that are considered more favorable for surgical success include short-segment stenosis, lesions that are further away from the vocal cords or glottis, and noninflammatory lesions. (See 'Surgery' above.)

●Refractory disease – In patients who fail local bronchoscopic therapy or surgery, are not good candidates for surgery, or need a bridge to surgery, a tracheostomy or T-tube (image 4) may be the only option to maintain a safe airway. (See 'Refractory disease' above.)

●Treatment of stenosis due to specific etiologies – Management of stenosis due to specific etiologies that should be taken into consideration together with the general principles are discussed in the table (table 2). (See 'Management of stenosis due to specific etiologies' above.)