Study on the rationality of small diameter metallic airway stent in treatment of tracheal stenosis in injured rabbits.

BACKGROUND: To observe the occurrence of related complications after self-expandable metallic (SEM) airway stents implantation with different diameters at different time points, and to provide theoretical basis for the optimal chioce of existing airway stents in clinical practice. METHODS: Healthy New Zealand white rabbits were used to establish benign tracheal stenosis models after chest CT examination. Forty-fivemodel rabbits with more than 50% of airway stenosis were divided into two groups. Small-diameter SEM stents (The ratio of stent diameter to airway diameter is nearly 1.0) were implanted in Group A in 21 rabbits, and large-diameter tracheal stents (The ratio of stent diameter to airway diameter is more than 1.2) were implanted in Group B in 24 rabbits. Stent-related complications were observed after stent implantation in 2nd,4th,8th, and 12th week by bronchoscopygross anatomy, pathological and the expressions of IL-1RA, IL-8 and MMP9 in involved tracheal. RESULTS: The incidence rate of tracheomalacia of stent was significantly higher in group B (24/24 100%) than that in group A (1 /21,4.8%) (P < 0.05). The incidence rate of scar contracture at both ends of stent was significantly higher than in group B (11 / 24,45.8%) that in group A (2 /21, 9.5%) (P < 0.05). The pathological results of both A and B showed that the columnar epithelium of bronchial mucosa began to damage and detach, inflammatory cells infiltrated after 2nd and 4th week of stenting, The epithelium was repaired, the lamina propria glands almost disappeared, collagen fiber proliferation was obvious, and scars were formed after 8th and 12th week of stenting. ELISA results revealed that the expressions of IL-1RA, IL-8, and MMP9 were increased in the stent group than in model rabbit with benign tracheal stenosis. IL-1RA and MMP9 increased at different periods in group B, but the expression of IL-1RA and MMP9 showed a tread of increasing in the early stage and then decreasing in group A. CONCLUSION: Metal stents can cause different degrees of stent-related complications in rabbits with benign tracheal stenosis. The incidence of stent-induced tracheomalacia and scar contracture were higher in Group B than that in Group A. IL-1RA, IL-8 and MMP9 may be involved in the development of complications after stentimplantation and peak value of group B movered backward. ing.

[Advances in the role of infection in the development of benign tracheal stenosis].

Benign tracheal stenosis (BTS) is a refractory disease with a complex pathogenesis and limited therapeutic drug effects. The management of benign tracheal stenosis remains a major challenge for the interventional physiologist. In recent years, the role of infection in the occurrence and development of tracheal stenosis has attracted some attention, but there is still some controversy. A clear understanding of the relationship between infection and tracheal stenosis is essential to elucidate the pathogenic mechanism of BTS, and then to improve early prevention and management of BTS. This article reviewed the research progress on BTS associated with infection to explore new effective interventions that can reduce the BTS.

The Wound Healing of Autologous Regenerative Factor on Recurrent Benign Airway Stenosis: A Canine Experimental and Pilot Study.

INTRODUCTION: Benign airway stenosis (BAS) is a severe pathologic condition. Complex stenosis has a high recurrence rate and requires repeated bronchoscopic interventions for achieving optimal control, leading to recurrent BAS (RBAS) due to intraluminal granulation. METHODS: This study explored the potential of autologous regenerative factor (ARF) for treating RBAS using a post-intubation tracheal stenosis canine model. Bronchoscopic follow-ups were conducted, and RNA-seq analysis of airway tissue was performed. A clinical study was also initiated involving 17 patients with recurrent airway stenosis. RESULTS: In the animal model, ARF demonstrated significant effectiveness in preventing further collapse of the injured airway, maintaining airway patency and promoting tissue regeneration. RNA-seq results showed differential gene expression, signifying alterations in cellular components and signaling pathways. The clinical study found that ARF treatment was well-tolerated by patients with no severe adverse events requiring hospitalization. ARF treatment yielded a high response rate, especially for post-intubation tracheal stenosis and idiopathic tracheal stenosis patients. CONCLUSION: The study concludes that ARF presents a promising, effective, and less-invasive method for treating RBAS. ARF has shown potential in prolonging the intermittent period and reducing treatment failure in patients with recurrent tracheal stenosis by facilitating tracheal mucosal wound repair and ameliorating tracheal fibrosis. This novel approach could significantly impact future clinical applications.

[Bilateral stenting for malignant tracheal and bronchial stenosis]. / Bilateral'noe stentirovanie opukholevogo stenoza trakhei i glavnykh bronkhov: pervyi opyt (klinicheskoe nablyudenie).

Malignant lesions of tracheal bifurcation usually lead to respiratory failure and risk of mortality. Airway stenting is the only minimally invasive method for these patients. The authors present a patient with T4N3M0 left-sided lung cancer (inoperable stage IIIc) complicated by respiratory failure due to tracheal bifurcation obstruction. Bilateral stenting by self-expanding stents with perforated coatings was effective for airway recanalization and provided subsequent chemotherapy.

Modified blade: an interventional option in rigid bronchoscopy for non-resectable benign tracheal stenosis.

INTRODUCTION: Benign tracheobronchial stenosis is a abnormal tracheal lumen narrowing that may incur progressive dyspnea and life-threatening hypoxemia. There is no consensus on which patients should be treated with endoscopic or surgical method. This study investigates the outcomes of bronchoscopic dilatation in the treatment of benign tracheal stenosis using a device equipped with a blade to cut the stenotic lesions with dense fibrosis. MATERIALS AND METHODS: The procedure was carried out in an operating room under general anesthesia. All patients were intubated with a Rigid Bronchoscope (RB) placed just above the stenosis. Through Rigid Bronchoscopy combined modalities were used as needed: radial incisions of the mucosal stenosis with blade at the levels of 4, 8 and 12 o'clock, with back and forth movements, then the stenotic area was dilated more easily with a rigid bronchoscope. Dilatation was performed by passing the RB of increasing diameter through stenotic areas and then Balloon dilatation of increasing diameter. There were no complications during the procedure. RESULT: We conducted an observational, retrospective, single-centre study in the Thoracic Surgery Unit of the University of 'Luigi Vanvitelli' of Naples from November 2011 to September 2021. We included all consecutive patients with benign tracheal stenosis inoperable. During the study period, 113 patients were referred to our department with benign tracheal stenosis inoperable. 61 patients were treated with the blade. During the follow-up, a recurrence of the stenosis was observed in 8 patients in the first month and in 4 patients in the third month. Instead in the patients treated with the use of laser (52 patients), during the follow-up a recurrence was observed in 16 patients in the first month and in 6 patients in the third month; no patient relapsed after 6 months and after 1 year. Long term successful bronchoscopic management with blade was attained by 99% in simple and 93% in mixed stenosis and in complex type stenosis. CONCLUSION: Our study underlines the importance of the use of the blade in bronchoscopic treatment as a valid conservative approach in the management of patients with inoperable benign tracheal stenosis as an alternative to the use of the laser, reducing the abnormal inflammatory reaction in order to limit recurrences.

Open airway surgery for post-COVID laryngotracheal stenosis.

INTRODUCTION: This study reports our experience with open reconstructive surgery in patients with laryngotracheal stenosis (LTS) following prolonged intubation and/or tracheostomy in the context of COVID-19. METHODS: All patients underwent a preoperative endoscopic airway assessment. Posterior glottic lesions were graded according to the Bogdasarian classification, subglottic-tracheal lesions according to the Cotton-Myers classification and postoperative complications reported by the Clavien-Dindo classification. We report postoperative outcomes and functional results in this patient subset. RESULTS: We include 14 patients diagnosed to have post COVID LTS, one female and 13 males. This group was compared with a control group, diagnosed with LTS following prolonged intubation. In the COVID group, mean age of patients at the time of the airway surgery was 52.1 ± 16.8 years (range: 13.7-76.3). More than half the patients were multi-morbid with hypertension and obesity being the most common conditions. Eleven patients had multi-site stenoses. Open surgical interventions performed were tracheal resection and anastomosis, laryngotracheal reconstruction and extended cricotracheal resection, and postoperative complications were seen in 12 (85.6%) patients. 70% patients with pre-existing tracheostomy were decannulated. Oral swallowing was not tolerated in one-fifth of the patients and a significant number of them have poor voice quality. CONCLUSION: Post-COVID pandemic, airway surgeons are seeing an increased number of patients with complex LTS, and we report significant postoperative complications in this patient subset. Decannulation rates, voice and swallowing results are poor in patients with glottic involvement as compared to isolated tracheal stenosis.

Interventional treatment of giant tracheal lymphoma under rigid bronchoscopy: A case report and literature review.

INTRODUCTION: Lymphoma can appear in all parts of the body and present with different symptoms. However, bronchial lymphoma is rare and can be misdiagnosed as airway malignancy or lung disease.Patient: An older adult woman with tracheal lymphoma experienced severe breathing difficulties, and chest computed tomography indicated severe narrowing of the airway. She did not respond to repeated antibiotic treatment, and she was eventually diagnosed with lymphoma based on pathology after surgical removal of the tumor. DIAGNOSIS: The patient received a diagnosis of thoracic tracheal stenosis due to intratracheal inflammatory granulomatous lesions or a tumor. INTERVENTIONS: Treatment involved the use of a high-frequency electrotome, freezing, and argon plasma coagulation. OUTCOMES: The patient reported improvements in dyspnea, cough, and other symptoms after the operation. The pathological results confirmed follicular lymphoma. Reexamination by fiberbronchoscopy indicated that the degree of stenosis in the middle and upper tracheal segments was significantly reduced following interventional therapy. CONCLUSION: Endoscopic interventional therapy can be an effective treatment for tracheal lymphoma.

Surgery for tracheal and laryngotracheal stenosis: a historical case series.

OBJECTIVES: Benign (laryngo-)tracheal stenosis is a relatively rare pathology and its surgical treatment is performed only at few specialized centres. This study aims to investigate outcomes after (laryngo-)tracheal resection-anastomosis, to explore potential risk factors for postoperative complications and to assess whether, over a 33-year period, there were major changes in surgical indications, techniques or outcomes. METHODS: Retrospective, single-centre review of all consecutive patients who underwent tracheal or laryngo-tracheal resection/anastomosis for benign pathologies from 1990 to 2023. RESULTS: Overall, 211 patients underwent tracheal (149 patients, 70.6%) and laryngo-tracheal (62 patients, 29.4%) resection-anastomosis. Of these, 195 patients (93.8%) were affected by iatrogenic stenosis, while 13 (6.2%) suffered from idiopathic stenosis. The median length of stenosis was 25 mm (interquartile range 1-3, 20-30). The overall morbidity rate was 27.5%, while major morbidity occurred in 10.5% of cases. One patient (0.5%) died in the postoperative period. Glottic oedema (17 patients, 8.1%), granulations (12 patients, 5.7%) and restenosis (10 patients, 4.7%) were the main complications. The only independent risk factor for postoperative complications was the length of the resected airway (P = 0.019). In the latest half of the study period, an older median age was observed, and no patient with idiopathic tracheal stenosis underwent surgery. Postoperative outcomes were comparable between surgical eras. CONCLUSIONS: Surgical treatment of (laryngo-)tracheal stenosis is challenging and should be performed by specialized centres. In our experience, morbidity and mortality rates were satisfactory, and in most cases, patients could breathe without tracheostomy. The length of the stenosis was the most significant risk factor for postoperative complications.

[Improving surgical technique for tracheal resection with anastomosis]. / Usovershenstvovanie khirurgicheskoi tekhniki pri rezektsii lineinoi chasti trakhei s posleduyushchim anastomozom.

OBJECTIVE: To present modern aspects of improving surgical techniques in tracheal resection developed in recent years. MATERIAL AND METHODS: The authors have the most extensive experience in tracheal surgery (>2.000 patients over the past 50 years). Diagnostic capabilities, perioperative management and surgical techniques have changed over such a long period. This concerns the proposed classification of cicatricial tracheal stenosis, features of endoscopic and X-ray diagnostics, indications for various surgeries, choice of surgical approach, technique of tracheal tube mobilization and anastomosis after tracheal excision. Preventive measures for severe postoperative complications are described. CONCLUSION: Such an extensive experience allowed the authors to develop an algorithm for the treatment of patients with tracheal stenosis. This significantly reduced the incidence of postoperative complications and mortality. Replication of such equipment is associated with technical support of hospitals and professional level of specialists consisting of endoscopist, anesthesiologist, intensive care specialist and thoracic surgeon.

Comparative evaluation of mechanical injury methods for establishing stable tracheal stenosis animal models.

The study aimed to assess the stability of various mechanical injury techniques in creating tracheal stenosis animal models using endoscopic assistance and investigate the viability of tracheal stoma in this process. Twenty-six healthy adult New Zealand white rabbits were randomly assigned to an experimental and control group. The experimental group underwent tracheal incision followed by steel brush scraping with endoscopic assistance, while the control group received nylon brush scraping. Within the control group, two subgroups were formed: Group A underwent scraping without tracheal stoma, and Group B underwent scraping followed by tracheal stoma. Additionally, a sham operation was performed on a separate group without subsequent scratching, resulting in no stenosis formation. Endoscopic observations were conducted at 7, 14, and 21 days post-scraping, followed by histological examinations of euthanized rabbits on the 21st day. Notably, all rabbits in the non-stoma group survived without complications, whereas Group B rabbits faced mortality post-operation. Histological assessments revealed inflammatory cell infiltration, fibroblast proliferation, and collagen fiber deposition in narrowed tracheal specimens. Steel brush scraping with endoscopic assistance proved more effective in inducing stable tracheal stenosis compared to nylon brush scraping. However, the survival challenges of rabbits with tracheal fistula require further investigation.

Comparison of Mechanical Forces used in Open Tracheotomy versus Percutaneous Tracheotomy Techniques.

OBJECTIVE: To understand the etiology of tracheotomy-induced tracheal stenosis by comparing the differences in techniques and mechanical force applied with open tracheotomy (OT) versus percutaneous tracheotomy (PCT) placement. METHODS: This study is an unblinded, experimental, randomized controlled study in an ex-vivo animal model. Simulated tracheostomies were performed on 10 porcine tracheas, 5 via a tracheal window technique (OT) and 5 using the Ciaglia technique (PCT). The applied weight during the simulated tracheostomy and the compression of the trachea were recorded at set times during the procedure. The applied weight during tracheostomy was used to calculate the tissue force in Newtons. Tracheal compression was measured by anterior-posterior distance compression and as percent change. RESULTS: Average forces for scalpel (OT) versus trocar (PCT) were 2.6 N and 12.5 N (p < 0.01), with the dilator (PCT) it was 22.02 N (p < 0.01). The tracheostomy placement with OT required an average force of 10.7 N versus 23.2 N (p < 0.01) with PCT. The average change in AP distance when using the scalpel versus trocar was 21%, and 44% (p < 0.01), with the dilator it was 75% (p < 0.01). The trach placement with OT versus PCT had an average AP distance change of 51% and 83% respectively (p < 0.01). CONCLUSION: This study demonstrated that PCT required more force and caused more tracheal lumen compression when compared to the OT technique. Based on the increased force required for PCT, we suspect there could also be an increased risk for tracheal cartilage trauma. LEVEL OF EVIDENCE: NA Laryngoscope, 134:103-107, 2024.

Inhalation of Carboxymethyl Chitosan Alleviates Posttraumatic Tracheal Fibrosis.

OBJECTIVES: The present study was performed to determine whether the inhalation of carboxymethyl (CM)-chitosan can alleviate tracheal fibrosis in a rabbit model. METHODS: We designed a rabbit model of tracheal stenosis involving electrocoagulation with a spherical electrode. Twenty New Zealand white rabbits were randomly divided into experimental and control groups (10 animals each). Tracheal damage was successfully established by electrocoagulation in all animals. The experimental group was given CM-chitosan (inhalation for 28 days), while the control group inhaled saline. The effects of CM-chitosan inhalation on tracheal fibrosis were analyzed. Laryngoscopy was performed to evaluate and grade tracheal granulation, while tracheal fibrosis was evaluated by histological examination. The effects of CM-chitosan inhalation on the tracheal mucosa were examined by scanning electron microscopy (SEM), and hydroxyproline content in tracheal scar tissue was determined by enzyme-linked immunosorbent assay (ELISA). RESULTS: Laryngoscopy showed that the tracheal cross-sectional area was smaller in the experimental than control group. The amounts of loose connective tissue and damaged cartilage, as well as the severity of collagen and fibrosis, decreased following inhalation of CM-chitosan. According to the ELISA, the experimental group had low levels of hydroxyproline in the tracheal scar tissue. CONCLUSION: The findings presented here showed that inhalation of CM-chitosan mitigated posttraumatic tracheal fibrosis in a rabbit model, thus suggesting a potential new treatment for tracheal stenosis.

Pediatric Airway Balloon Dilation: Urge for Safety Redesign.

Airway balloons are widely used by otolaryngologists to treat laryngotracheal stenosis. We review an adverse event and interventions that may prevent similar occurrences. There are no other reports of similar incidents in the Food and Drug Administration Manufacturer and User Facility Device Experience. We implore Acclarent to redesign their airway balloon device to prevent accidental airway irrigation.

Predictors of Clinical Outcomes in Adult Laryngotracheal Stenosis.

OBJECTIVES: Sequelae of laryngotracheal stenosis (LTS) can be devastating, often necessitating tracheostomy. This study aims to describe the characteristics and outcomes of patients with LTS and identify risk factors for long-term tracheostomy dependence stratified by etiology. METHODS: A retrospective chart review was performed on 215 patients diagnosed with LTS from 09/01/2011 to 12/31/2020. Patients were grouped based on the cause of LTS. Patient factors were compared to evaluate risk factors for long-term tracheostomy dependence. RESULTS: Of the 215 patients, 129 (60%) were classified as iatrogenic, 41 (19%) idiopathic, 10 (4.7%) cancer treatment, 18 (8.3%) autoimmune, and 17 (8%) patients unknown. Idiopathic patients were significantly less likely to be tracheostomy-dependent compared with iatrogenic patients (p < 0.001) and cancer patients (p < 0.05). The mortality rate did not significantly differ among the categories (p = 0.1078). Significant improvement was seen after treatment, as the median percent of stenosis at presentation was 52.5%, and the median percent of stenosis at the most recent visit was 10% (p < 0.001). The autoimmune group received the most steroid injections (mean = 6.56; SD = 11.96). The idiopathic group had the longest surgery-free interval (mean = 30.8 months; SD = 27.7). CONCLUSION: Iatrogenic and cancer patients were more likely to be tracheostomy-dependent. There was a significant improvement in percent and length of stenosis after treatment, with the idiopathic group having the longest surgery-free interval. Mortality risk did not differ among the different etiologies of LTS. LEVEL OF EVIDENCE: 3 Laryngoscope, 134:257-263, 2024.

Mechanisms of fibrosis in iatrogenic laryngotracheal stenosis: New discoveries and novel targets.

Iatrogenic laryngotracheal stenosis (iLTS) is a pathological condition characterized by the narrowing of the laryngeal and tracheal structures due to the formation of abnormal scar tissue. The core of iLTS lies in the fibrosis of the laryngotracheal tissue, and recent research has unveiled novel discoveries regarding the underlying mechanisms of fibrosis. This review provides an overview of the recent advancements in understanding the mechanisms of fibrosis in iLTS. It encompasses various aspects, such as immune system dysregulation, changes in the extracellular matrix (ECM), metabolic alterations, and the role of microbial flora. The review also explores the interplay and relationships between these new mechanisms, establishing a theoretical foundation for the development of multi-target therapies and combination therapies for iLTS.

Predictors of response to endoscopic management of subglottic/tracheal stenosis in patients without tracheostomy.

INTRODUCTION: Subglottic and tracheal stenosis (SGTS) in adults is an acquired or idiopathic condition that can lead to dyspnea, and even life-threatening airway obstruction. Endoscopic techniques have advanced and largely eclipsed open surgery, with open surgery now reserved for refractory cases (Hseu et al., 2013; Feinstein et al., 2017). Currently, there is no accepted guideline for the endoscopic treatment of SGTS. Thus, the aim of the present study is to examine the impact of various clinical and pathological characteristics on outcomes to endoscopic treatment in a cohort of SGTS patients. DISCLOSURE: None of the authors have any financial or personal relationship that could cause a conflict of interest regarding this article. METHODS: Retrospective chart review was performed for 41 patients presenting with SGS without a tracheostomy over a 4-year-period (2018-2022), within a single tertiary care center. Quantitative outcomes including number of dilation procedures undergone and need for open procedures were examined. The qualitative variables included a history of pulmonary disease, prior tracheostomy/tracheal resection, presence of tracheomalacia, granulation tissue, excessive dynamic airway collapse (EDAC), and etiology of idiopathic subglottic stenosis. RESULTS: The presence of granulation tissue seen on tracheoscopy was associated with a higher number (4+) of dilation procedures (p = 0.01). A history of pulmonary disease (p = 0.037), the presence of tracheomalacia (p = 0.039), and the presence of granulation tissue (0.003) were all associated with a need for open procedures. CONCLUSION: Patients with the presence of granulation tissue, tracheomalacia, and a history of pulmonary disease were more associated with more severe disease requiring either a higher number of endoscopic procedures or need for open procedures.

A case of tracheal stenosis due to anaplastic thyroid carcinoma treated using the stent-in-stent method.

Tracheal AERO stent collapse is a rare complication compared to bronchial AERO stent collapse due to differences in the nitinol framework thickness. A 58-year-old man with a bulky anaplastic thyroid carcinoma was referred to our hospital due to exacerbation of tracheal stenosis despite the administration of lenvatinib. His tracheal stenosis exhibited a severe extrinsic compression pattern with a length of 8 cm. Because tracheotomy was inappropriate, we placed an 18 × 80 mm AERO stent. Five months later, he was readmitted with severe dyspnea due to collapse of the distal portion of the stent caused by tumor growth. Because stent removal was difficult, we placed an additional AERO stent (18 × 60 mm) to cover the collapsed portion. The additional stent successfully expanded the collapse and improved his dyspnea. To our knowledge, this is the first case where a tracheal AERO stent collapse due to a poor prognosis tumor was treated with the stent-in-stent method.