Utilizing a Functional Lumen Imaging Probe for Evaluation of the Pediatric Airway, A Pilot Study.

OBJECTIVES: Accurate and reproducible measurements of the pediatric airway are critical for diagnostic evaluation and management of subglottic and tracheal stenosis. The endoluminal functional lumen imaging probe (EndoFLIP) is a catheter-based imaging probe which utilizes impedance planimetry to calculate luminal parameters, including cross-sectional area and compliance. Herein, we demonstrate the feasibility of this system for multidimensional evaluation of the pediatric airway. METHODS: 3D-printed pediatric laryngotracheal models were created based on computed tomography scans, then artificially deformed to simulate both circumferential and posterior subglottic stenosis. Two observers made six measurements of the minimum cross-sectional area (MCSA) and length of stenosis of each model with EndoFLIP. Agreement between observer measurements and model dimensions was evaluated using Lin's concordance correlation coefficient; inter-observer reliability was assessed using intraclass correlation. RESULTS: Four models were created: two without pathology (MCSA: 132.4, 44.3 mm2 ) and two with subglottic stenosis (MCSA: 28.7, 59.7 mm2 , stenotic length 27.8, 24.4 mm). Observer measurements of MCSA and length of stenosis demonstrated high concordance with the models (r = 0.99, 0.95, p < 0.001) with a mean error of 4.5% and 18.2% respectively. There was a low coefficient of variation (0.6%-2.8%) for measurements, indicating high precision. Interrater reliability was high for both MCSA and stenotic length (ICC: 0.99, 0.98). CONCLUSIONS: The EndoFLIP system allows for accurate and reproducible measurements of cross-sectional area and stenotic length in pediatric airway models. This method may provide further advantages in the evaluation of airway distensibility, as well as measurements of asymmetric airway pathology. LEVEL OF EVIDENCE: NA Laryngoscope, 134:108-112, 2024.

Management of post-traumatic tracheal stenosis with silicone stent placement.

Benign airway stenosis often poses a therapeutic challenge and requires a multidisciplinary approach involving interventional pulmonologists and thoracic surgeons. We report the case of a man who presented with thoracic trauma following a road traffic accident. His chest X-ray showed complete collapse of the right lung, while screening flexible bronchoscopy revealed pooled secretions and asymmetric mid-to-lower tracheal stenosis. After thorough clinicoradiological evaluation and multidisciplinary discussion, we proceeded with therapeutic rigid bronchoscopy and silicone stenting of the tracheal stenotic lesion. Post-procedure, the patient improved clinically and also showed radiological improvement. Subsequently, he underwent stent removal and remains in follow-up. While surgery is a definitive modality for management of benign tracheal stenosis, most patients with advanced disease, pneumonia or with poor general condition are unfit to tolerate general anaesthesia or surgery. In such patients, minimally invasive bronchoscopic techniques that are generally safe to perform have led to substantial improvement in symptoms and long-term quality of life.

Comparison of Inhaled Drug Delivery in Patients With One- and Two-level Laryngotracheal Stenosis.

OBJECTIVES/HYPOTHESIS: Laryngotracheal stenosis (LTS) is a functionally devastating condition with high respiratory morbidity and mortality. This preliminary study investigates airflow dynamics and stenotic drug delivery in patients with one- and two-level LTS. STUDY DESIGN: A Computational Modeling Restropective Cohort Study. METHODS: Computed tomography scans from seven LTS patients, five with one-level (three subglottic, two tracheal), and two with two-level (glottis + trachea, glottis + subglottis) were used to reconstruct patient-specific three-dimensional upper airway models. Airflow and orally inhaled drug particle transport were simulated using computational fluid dynamics modeling. Drug particle transport was simulated for 1-20 µm particles released into the mouth at velocities of 0 m/s, 1 m/s, 3 m/s, and 10 m/s for metered dose inhaler (MDI) and 0 m/s for dry powder inhaler (DPI) simulations. Airflow resistance and stenotic drug deposition in the patients' airway models were compared. RESULTS: Overall, there was increased airflow resistance at stenotic sites in subjects with two-level versus one-level stenosis (0.136 Pa s/ml vs. 0.069 Pa s/ml averages). Subjects with two-level stenosis had greater particle deposition at sites of stenosis compared to subjects with one-level stenosis (average deposition 2.31% vs. 0.96%). One-level stenosis subjects, as well as one two-level stenosis subject, had the greatest deposition using MDI with a spacer (0 m/s): 2.59% and 4.34%, respectively. The second two-level stenosis subject had the greatest deposition using DPI (3.45%). Maximum deposition across all stenotic subtypes except one-level tracheal stenosis was achieved with particle sizes of 6-10 µm. CONCLUSIONS: Our results suggest that patients with two-level LTS may experience a more constricted laryngotracheal airflow profile compared to patients with one-level LTS, which may enhance overall stenotic drug deposition. LEVEL OF EVIDENCE: NA Laryngoscope, 133:366-374, 2023.

Heliox simulations for initial management of congenital laryngotracheal stenosis.

OBJECTIVES: Congenital laryngotracheal stenosis is rare, potentially severe, and difficult to manage. Heliox is a medical gas effective in obstructive airway pathologies, given its physical properties. This study aims to model the interest of Heliox in reducing the respiratory work in congenital laryngotracheal stenosis, using numerical fluid flow simulations, before considering its clinical use. DESIGN: This is a retrospective study, performing Computational Fluid Dynamics numerical simulations of the resistances to airflow and three types of Heliox, on 3D reconstructions from CT scans of children presenting with laryngotracheal stenosis. PATIENTS: Infants and children who were managed in the Pediatric ENT department of a tertiary-care center and underwent CT scanning for laryngotracheal stenosis between 2008 and 2018 were included. RESULTS: Fourteen models of congenital laryngotracheal stenosis were performed in children aged from 16 days to 5 years, and one model of the normal trachea in a 5-year-old child. Tightest stenosis obtained the highest airway resistances, ranging from 40 to 10 kPa/L/s (up to 800 times higher than in the normal case). Heliox enabled a decrease in pressure drops and airway resistances in all stenosis cases, correlated to increasing Helium concentration. CONCLUSIONS: Heliox appears to reduce pressure drops and airway resistances in 3D models of laryngotracheal stenosis. It may represent a supportive treatment for laryngotracheal stenosis, while waiting for specialized care, thanks to the reduction of respiratory work.

Outcomes of pulmonary artery sling repair without tracheoplasty.

OBJECTIVE: This study aimed to investigate surgical outcomes of pulmonary artery (PA) sling without tracheoplasty. METHODS: From 2001 through 2020, among 22 patients who underwent PA sling repair, all but 1 patient who underwent concomitant tracheal surgery were analyzed. The outcomes of interest were all-cause death, PA reintervention, tracheal intervention, and readmission for respiratory symptoms. Computed tomography was used to measure the narrowest tracheal diameter. RESULTS: The median age and weight at repair were 7.6 months and 7.7 kg, respectively. Most patients (20 out of 21, 95.2%) had preoperative respiratory symptoms. Associated airway anomalies included tracheal ring in 12 (57.1%), bridging bronchus in 8 (38.1%), and tracheal bronchus in 2 patients (9.5%). There was 1 in-hospital death (4.8%). The median ventilator time and intensive care unit stay were 23 hours and 3 days, respectively. There was neither late death nor tracheal intervention during follow-up. Five patients (25.0%) underwent reintervention for left PA stenosis. Hospital readmission for respiratory symptom was required in 7 patients and was associated with the narrowest preoperative tracheal diameter (P = .025) and cardiopulmonary bypass time (P = .040) in univariable analysis. The narrowest tracheal diameter of 3.4 mm was identified as a cutoff value for readmission for respiratory symptom. Freedom from readmission for respiratory symptom was 63.3% at 10 years. CONCLUSIONS: PA sling repair without tracheal surgery might be a reasonable surgical option with rare need for tracheal intervention. Hospital readmissions for respiratory symptoms are more frequently required in patients with smaller tracheal diameter and all readmissions were limited to within 2 years after repair.

Computational fluid dynamics assessment of congenital tracheal stenosis.

PURPOSE: The severity of congenital tracheal stenosis (CTS) is commonly evaluated based on the degree of stenosis. However, it does not always reflect the clinical respiratory status. We applied computational fluid dynamics (CFD) to the assessment of CTS. The aim of this study was to evaluate its validity. METHODS: CFD models were constructed on 15 patients (12 preoperative models and 15 postoperative models) with CTS before and after surgery, using the computed tomographic data. Energy flux, needed to drive airflow, measured by CFD and the minimum cross-sectional area of the trachea (MCAT) were quantified and evaluated retrospectively. RESULTS: The energy flux correlated positively with the clinical respiratory status before and after surgery (rs = 0.611, p = 0.035 and rs = 0.591, p = 0.020, respectively). Although MCAT correlated negatively with the clinical respiratory status before surgery (rs = -0.578, p = 0.044), there was not significant correlation between the two after surgery (p = 0.572). CONCLUSIONS: The energy flux measured by CFD assessment reflects the respiratory status in CTS before and after surgery. CFD can be an additional objective and quantitative evaluation tool for CTS.

Clinical Application of Spiral CT Reconstruction Imaging in Patients with Tracheal Stenosis before Anesthesia.

In order to solve the problem of CT reconstruction imaging, this paper presents a study on the clinical application of preanesthesia in patients with tracheal stenosis. Patients with tracheal stenosis and multislice spiral CT virtual endoscopy (CTVE) were diagnosed, and their application effects were analyzed. Methods. 60 patients with tracheal stenosis were selected for clinical observation. The patients were given tracheal stenosis examination and multislice spiral CT virtual endoscopy. The examination results of the two groups were compared and analyzed by statistical methods. Results. There was no significant difference in the detection rate, sensitivity, accuracy, and specificity between the two groups (P > 0.05). Conclusion. Multislice spiral CT virtual endoscopy combined with a fiberoptic bronchoscope for clinical diagnosis of tracheal stenosis can complement each other. Combined use can effectively improve the detection consistency, and is safe and reliable. It can be used as an effective means for the diagnosis of tracheal stenosis.

[Measuring laryngotracheal stenosis by extracting centerline based on CT 3D reconstruction].

Objective: To compare the accuracy of the centerline extracted based on CT 3D reconstruction and conventional CT 3D reconstruction in measuring the length and degree of laryngotracheal stenosis. Methods: A retrospective analysis was performed on 35 patients with laryngotracheal stenosis (including 19 cases without tracheotomy and 16 cases with tracheotomy) treated in the Department of Otorhinolaryngology Head and Neck Surgery of the First Affiliated Hospital of Guangxi Medical University from March 2006 to March 2016, including 20 males and 15 females, whose ages ranged from 1 to 73 years, with a median age of 40.5 years. And CT data of 20 normal subjects were included in the same period, including 10 males and 10 females, whose ages ranged from 20 to 63 years, with a median age of 37.0 years. The continuous cross-sectional area of the airway perpendicular to the centerline was obtained by Mimics software. The area was compared with the discontinuous cross-sectional areas reconstructed by conventional CT 3D reconstruction software advantage workstation, also the length of cervical trachea, the length of stenosis, and the minimum airway area were compared. Multi-factor linear stepwise regression method was used to analyze the factors influencing the measuring difference between the two methods. Three patients with laryngotracheal stenosis were selected, and the measured stenosis length was compared with the surgical specimens to evaluate the accuracy of the two methods. SPSS 26.0 software was used for statistical analysis. Results: In normal people, the areas of thyroid cartilage notch, glottis, inferio thyroid cartilage margin, inferio cricoid cartilage margin, and suprasternal notch planes measured by Mimics centerline method were smaller than those measured by conventional CT 3D reconstruction (t thyroid cartilage notch=4.685, tglottis=3.791, tlower thyroid cartilage margin=5.621, tlower cricoid cartilage margin=6.312, tsuprasternal notch plane=6.436, P<0.05). And the airway length measured by Mimics centerline method from the inferior thyroid cartilage to the superior sternal notch was longer (t=9.79, P<0.001). In laryngotracheal stenosis, in the non-tracheotomy group, the minimum airway area measured by Mimics centerline method was smaller and the stenosis length was longer than those measured by the conventional CT 3D reconstruction, and the difference was statistically significant (tminimum airway area=2.562, tstenosis length=5.240, P<0.05). In the tracheotomy group, the stenosis length measured by Mimics centerline method was longer than that measured by conventional CT 3D reconstruction, and the difference was statistically significant (tstenosis length=2.854, P<0.05). Multi-factor linear regression analysis showed that different CT thickness had a statistically significant effect on the difference in the length of stenosis measured by the two methods (b=-5.370, t=-3.306, P=0.004), and different tracheal forward angle had a statistically significant effect on the difference in the minimum airway area measured by the two methods (b=-0.419, t=-2.208, P=0.04). The difference between the measured length of the Mimics centerline method and the intraoperative specimens was less than 0.5 mm. Conclusion: The centerline extracted based on CT 3D reconstruction can precisely reflect the laryngotracheal morphology and measure laryngotracheal stenosis more accurately.

Infliximab therapy of relapsing tracheal stenosis in a pediatric patient with granulomatosis with polyangiitis: a case report.

BACKGROUND: Granulomatosis with polyangiitis is a granulomatous, necrotizing small-vessel vasculitis affecting both children and adults. However, subglottic tracheal stenosis appears more frequently in the pediatric cohort. To date, granulomatosis with polyangiitis is often treated with steroids, cyclophosphamide, azathioprine, or rituximab, but tumor-necrosis-factor-α-antagonistic drugs are increasingly gaining significance in treatment of refractory cases. CASE PRESENTATION: We report the case of a 15-year-old Caucasian male diagnosed with proteinase-3-positive granulomatosis with polyangiitis with acute shortness of breath. X-ray and magnet resonance imaging showed extensive subglottic narrowing. Forced expiratory volume in 1 s was reduced to 50% of age norm, with massively increased effective airway resistance. The patient initially responded very well to high-dose steroids and maintenance therapy with azathioprine. He was subsequently treated with four doses of rituximab, and levels of proteinase 3 antibodies normalized. After 6 months of clinical remission, the patient presented again with acute respiratory symptoms. Again, he was treated with high-dose steroids, but showed poor clinical response this time. Therefore, we decided to commence a tumor-necrosis-factor-α-antagonistic treatment with infliximab, under which our patient achieved clinical remission and normalization of lung function parameters. CONCLUSIONS: The use of tumor-necrosis-factor-α-antagonistic agents might be a promising alternative for the treatment of refractory tracheal stenosis in pediatric patients with granulomatosis with polyangiitis.

Tracheal Stenosis After Prolonged Intubation Due to COVID-19.

OBJECTIVES: The authors aimed to evaluate the characteristics and management outcomes of patients who developed tracheal stenosis after invasive mechanical ventilation (IMV) due to COVID-19. DESIGN, SETTING, AND PARTICIPANTS: The data of 7 patients with tracheal stenosis and 201 patients without tracheal stenosis after IMV due to COVID-19 between March 2020 and October 2021 were retrospectively analyzed. INTERVENTIONS: Flexible bronchoscopy was performed for the diagnosis of tracheal stenosis and the evaluation of the treatment's effectiveness, and rigid bronchoscopy was applied for the dilatation of tracheal stenosis. MEASUREMENTS AND MAIN RESULTS: In the follow-up period, tracheal stenosis was observed in 7 of 208 patients (2 women, 5 men; 3.3%). The patients were divided into 2 groups as patients with tracheal stenosis (n = 7) and patients without tracheal stenosis (n = 201). There were no statistically significant differences between the 2 groups in terms of age, sex, body mass index, and comorbidities (p > 0.05). The mean duration of IMV of the patients with tracheal stenosis was longer than patients without tracheal stenosis (27.9 ± 13 v 11.2 ± 9 days, p < 0.0001, respectively). Three (43%) of the stenoses were web-like and 4 (57%) of them were complex-type stenosis. The mean length of the stenoses was 1.81 ± 0.82 cm. Three of the patients were treated successfully with bronchoscopic dilatation, and 4 of them were treated with tracheal resection. CONCLUSIONS: Tracheal stenosis developed in 7 of 208 (3.3%) patients with COVID-19 who were treated with IMV. The most important characteristic of patients with tracheal stenosis was prolonged IMV support.

Tracheal Stent Buckling and In-stent Stenosis: A Proposed Airway Management Algorithm for Airway Obstruction for Patients With Tracheal Stents.

EMERGENCY AIRWAY management strategies for patients with complications due to tracheobronchial stents are of growing interest to anesthesiologists. Although tracheal stenting increasingly is used to manage tracheobronchial stenosis of both benign and malignant conditions,1-3 official guidelines for the perioperative airway management of patients with tracheobronchial stents in situ are lacking.3 Here, the authors discuss the management of airway obstruction from a tracheal stent strut protrusion and in-stent stenosis in a patient with a self-expanding nitinol tracheal stent in situ. They discuss the airway management strategy employed and outline a pragmatic airway management algorithm for patients with tracheal stents presenting with airway obstruction.