Treatment of Idiopathic Laryngotracheal Stenosis

Down-Regulation of a Profibrotic Transforming Growth Factor-β1/Cellular Communication Network Factor 2/Matrix Metalloprotease 9 Axis by Triamcinolone Improves Idiopathic Subglottic Stenosis

Idiopathic subglottic stenosis (iSGS) is a progressive fibrotic disease characterized by life-threatening airway narrowing. Although the molecular underpinnings are unknown, previous reports showing that subglottic serial intralesional steroid injections (SILSIs) improve clinical outcomes suggest a steroid-sensitive pathway in iSGS. Herein, a prospective study was conducted to determine the changes in profibrotic markers during SILSI to identify steroid-sensitive profibrotic drivers. Seven newly diagnosed patients with iSGS were recruited for SILSI. Subglottic biopsies before and after SILSI treatments were evaluated for histologic and molecular markers by confocal microscopy and RT-qPCR. At baseline, iSGS subglottises contained abundant vimentin-positive/α-smooth muscle actin-negative fibroblasts, intermingled with a matrix of fibronectin and types I and VI collagen. Transforming growth factor (TGF)-β1 was up-regulated primarily in glandular epithelium. Cellular communication network factor 2 (CCN2) was mainly up-regulated in stromal fibroblasts surrounding TGF-β1-positive glandular structures. SILSI improved iSGS by reducing fibroblast infiltration and increasing matrix remodeling. Mechanistically, SILSI counteracted the effects of TGF-β1 by inducing matrix metalloprotease 9 (MMP9) expression while repressing CCN2 expression, without affecting TGFβ1 levels. Treatment of primary iSGS-derived fibroblasts with TGF-β1 recapitulated aspects of the disease in vivo, demonstrating that the induction in CCN2 and repression of MMP9 are caused by changes in histone acetylation induced by TGF-β1. Triamcinolone counteracted the coregulation of these genes by impairing SMAD2/3 binding to promoter regions, and not through histone acetylation. In conclusion, this study shows that SILSI counteracts a dysregulated TGF-β1/CCN2/MMP9 axis involved in iSGS development.

Idiopathic subglottic stenosis: techniques and results

Idiopathic subglottic stenosis is a rare condition of unknown etiology characterized by circumferential stenosis in the subglottic larynx and upper trachea. Historically, patients were treated with dilation or ablation, however this approach has proven to be largely palliative and often leads to recurrence and the need for tracheostomy. A single-staged laryngotracheal resection and reconstruction is now the preferred definitive treatment for idiopathic subglottic stenosis and can be performed with excellent patient outcomes and rare subsequent progression of the disease. Avoiding anastomotic tension and devascularization are important technical keys to minimizing complications.

Idiopathic laryngotracheal stenosis

Idiopathic laryngotracheal stenosis (ILTS) is a rare inflammatory disease of unknown etiology. Infectious, traumatic and immunologic processes must first be excluded. The majority of patients affected are female who present with progressive symptoms of upper airway obstruction, which can extend over a number of years. ILTS is characterized by short segment, circumferential stenotic lesions, located particularly at the level of the cricoid. Bronchoscopic evaluation is essential for establishing the diagnosis and operative planning. Various temporizing interventions have historically been utilized, including dilation and laser ablation, for symptomatic management. However these interventions have demonstrated diminishing returns and poor long-term outcomes. Patients with ILTS should be considered early for definitive surgical intervention to minimize complications and optimize outcomes. Laryngotracheal resection and reconstruction is a viable intervention, which has demonstrated good long-term results and low recurrence rates for this patient population.

Microscopic examination of iatrogenic subglottic tracheal stenosis: observations that may elucidate its histopathologic origin

OBJECTIVES

The histopathologic origin of iatrogenic subglottic tracheal stenosis (ISTS) remains unclear. The purpose of this study was to use detailed operative microscopy to systematically examine the operative en bloc specimens of patients with ISTS and to observe the histologic and morphological changes in the hopes that these observations will provide insight into the histopathologic origin of these devastating injuries.

METHODS

The operative specimens of 18 patients who underwent open tracheal or laryngotracheal resection for ISTS were examined. Precise morphological characteristics were investigated for each tissue layer, including the adventitia, the outer surface of the perichondrium, the cartilage, the inner surface of the perichondrium, the submucosa, and the mucosa. Each tissue layer was evaluated independently and in relationship to the other layers. The cartilaginous airway was further evaluated relative to the pars membranacea.

RESULTS

The most common morphological finding in the epithelium was squamous metaplasia with occasional intense inflammation visible in the underlying mucosa, including cicatrization. The underlying cartilage demonstrated ossific metaplasia with sequestration in many cases. By far the most pronounced changes were found in the outer perichondrium and overlying adventitia and included diffuse paucicellular or hyperplastic fibrosis with intense hyperplastic scar formation or hyaline cicatrization. In the pars membranacea, severe scar formation and hyperplastic fibrosis were predominant. Ossific metaplasia was particularly severe in the lateral or outer parts of the tracheal ring, particularly in the vicinity of the adventitia and outer perichondrium. These changes were much more pronounced than the relatively minor changes observed in the submucosa and mucosa.

CONCLUSIONS

The most severe pathologic observations occurred in the lateral tissue layers, ie, the outer perichondrium and adventia. Given that an injury occurs from the tracheal lumen, these tissue layers have the greatest distance from the site of injury. As only minor changes occurred in the inner tissue layers, we hypothesize that these tissues have a greater regenerative capacity than the outer layers. This study supports the theory that the depth of the airway injury is more critical to the development of ISTS than is the extent or length of the injury.

Non-malignant central airway obstruction

The most common causes of non-malignant central airway obstruction are post-intubation and post-tracheostomytracheal stenosis, followed by the presence of foreign bodies, benign endobronchial tumours and tracheobronchomalacia. Other causes, such as infectious processes or systemic diseases, are less frequent. Despite the existence of numerous classification systems, a consensus has not been reached on the use of any one of them in particular. A better understanding of the pathophysiology of this entity has allowed us to improve diagnosis and treatment. For the correct diagnosis of nonspecific clinical symptoms, pulmonary function tests, radiological studies and, more importantly, bronchoscopy must be performed. Treatment must be multidisciplinary and tailored to each patient, and will require surgery or endoscopic intervention using thermoablative and mechanical techniques.

Single-staged laryngotracheal reconstruction for idiopathic tracheal stenosis

BACKGROUND

This study retrospectively evaluated the results of surgically treated idiopathic tracheal stenosis.

METHODS

Of the 220 patients surgically treated for idiopathic subglottic and tracheal stenosis in the participating hospitals, we reviewed the surgical records of all patients with idiopathic tracheal stenosis. This subgroup required resection of all of the involved mucosa but frequently had undergone more conservative treatments that damaged the tracheal mucosa and cartilage and complicated the definitive surgical treatment.

RESULTS

During the study period, 60 women (93.8%) and 4 men (6.2%), who were a mean age of 50 years (range, 19 to 77 years), were surgically treated for idiopathic tracheal stenosis, with no operative deaths. Of these 64 patients, 38 (59.3%) had undergone previous treatments in other centers: dilation, 26 (40.6%); laser only, 19 (31%); laser plus tracheal prosthesis, 5 (7.8%); tracheostomy, 7 (11.6%); T tube, 2 (3%); and laryngotracheal operations, 5 (7.8%). All patients were treated with a single-staged tracheal or laryngotracheal operation, of which 59 (98%) successful. Four of the most complex stenoses, with vocal cords and cricoid plate involvement, underwent reoperation for restenosis or larynx inconsistency. One patient was considered biologically unfit for reoperation and required a permanent T tube for restenosis. Half of the operations were temporary tracheostomies with T tube for larynx modelling. The most frequent postoperative complications were dysphonic voice in 10 patients (although in 7 instances this began months or years before the operation), granulation tissue in 10, aspiration in 3, and wound infections in 2.

CONCLUSIONS

Idiopathic stenosis occurred predominantly (90% of cases) in women. Single-staged laryngotracheal correction was successful in 97%. Technique selection, with or without temporary laryngeal stenting, must be individualized with respect to the vocal cords' mobility, function, and distance from the stenosis.

[Successful treatment of subglottic tracheal stenosis with a mucosa-lined radial forearm fascia flap]

Short-segment tracheal stenosis is often treated by segmental resection and end-to-end anastomosis. Longer-segment stenosis can sometimes be treated using dilation, laser therapy, bronchoscopic stent insertion and segmental resection and reconstruction. Long-segment restenosis with a buildup of scar tissue due to successful resection surgery in the past represents a particular therapeutic challenge and a sufficiently vascularized transplant may be the only option. We describe the case of a 37-year-old patient who underwent a tracheal reconstruction using a mucosa-lined radial forearm flap. Subsequent to a traumatic laryngotracheal fracture, long-term ventilation and multiple surgical interventions, the patient had developed a functionally relevant subglottic stenosis (5.5 cm). Following longitudinal anterior resection of the trachea 1 cm above and below the stenosis, a Dumon® stent was inserted. Simultaneously, a radial forearm fascia flap was harvested, as were two full-thickness buccal mucosa grafts, which were sutured onto the subcutaneous tissue and fascia of the forearm flap. Beginning caudally, the mucosa-lined flap was then sutured, air-tight, into the anterior tracheal defect with the mucosa facing the lumen. Finally, end-to-end anastomosis connected the blood vessels of the radial forearm flap to the recipient blood vessels in the neck. The patient was successfully extubated after 24 h and discharged after 5 days. A postoperative CT scan revealed optimal placement of the stent and the patient's speech and breathing were sufficiently re-established. The stent was removed bronchoscopically 6 weeks after surgery. Examinations during the 6-month follow-up period showed that the diameter of the reconstructed airway was retained and the patient remained symptom-free.

Endoscopic management of idiopathic tracheal stenosis

BACKGROUND

Idiopathic tracheal stenosis (ITS) is a rare condition representing a difficult therapeutic challenge. Endoscopic management is a therapeutic option but long-term results are not established. The aim of this retrospective multicenter study was to analyze long-term outcome after endoscopic management of ITS.

METHODS

Nine institutions involved in interventional bronchoscopy were contacted and asked to identify ITS endoscopically treated. A standard form was used to report the main characteristics and long-term outcome after endoscopic management.

RESULTS

Twenty-three patients, 96% women, aged 45±16 years, were endoscopically treated for ITS. Time between first symptoms and diagnosis was 19±18 months. Bronchoscopy showed a weblike (61%) or complex (39%) stenosis, located in the upper part of the trachea, mainly in the cricoid area. Endoscopic treatment included mechanical dilation only (52%) or associated with laser or electrocoagulation (30%) and stent placement (18%). All procedures were efficient. The follow-up after endoscopic management was 41±34 months. The ITS recurrence occurred in 30% at 6 months, 59% at 2 years, and 87% at 5 years, with a delay of 14±16 months. The treatment of recurrence (n=13) included endoscopic management in 12 cases.

CONCLUSIONS

Endoscopic management of ITS provides a safe and efficient therapeutic option but late recurrences are frequent and require long-term follow-up.