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.

Computational fluid dynamics model of laryngotracheal stenosis and correlation to pulmonary function measures.

3D models of airway lumens were created from CT scans of 19 patients with laryngotracheal stenosis. Computational fluid dynamics (CFD) simulations were completed for each, and results were compared to measured peak inspiratory flow rate, grade of lumen constriction, and measures of airway geometry. Results demonstrate flow resistance and shear stress correlate with degree of lumen constriction and absolute cross-sectional area as well as flow rate. Flow recirculation depends on airway constriction but does not vary with flow rate. Resistance and wall shear stress did not correlate well with functional measures. Flow recirculation did differ between subjects with higher functional measures and subjects with lower functional measures. This analysis provides mathematical models to predict airway resistance, wall shear stress, and flow reversal according lumen constriction and inspiratory flow rate. It suggests aerodynamic factors such as flow recirculation play a role in differences in functional performance between patients with similar airway measures.

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.

Postlaryngectomy supraglottic stenosis revealed by three-dimensional computed tomography reconstruction: A case report.

RATIONALE: Supraglottic stenosis is a rare cause of airway obstruction. It can be induced by radiation, trauma, autoimmune diseases, or caustic exposure, and is often misdiagnosed as asthma. Detailed airway information is necessary to re-establish the normal functioning of the airway. PATIENT CONCERNS: A 78-year-old woman with severe dyspnea and hypercarbia was scheduled for surgery to resolve airway obstruction, previously known as supraglottic stenosis. DIAGNOSES: To determine the exact internal shape of the stenotic lesion, we reconstructed three dimensional computed tomography (CT) images depicted a tubular supraglottic stenosis. INTERVENTIONS: The patient underwent tracheotomy under monitored anesthesia care and local anesthesia, followed by general anesthesia. For long-term management of the patient, the otorhinolaryngologist excised the supraglottic stricture via micro-laryngeal surgery using a CO2 laser and applied mitomycin to prevent further obstruction. OUTCOMES: The patient recovered uneventfully after anesthesia, and symptom due to supraglottic stenosis was improved. LESSONS: During airway management of patients with postlaryngectomy supraglottic stenosis, three-dimensional reconstructed computed tomography images facilitate airway configuration in addition to endoscopy and other radiological findings.

Correlation of airway ultrasonography and laryngoscopy findings in adults with subglottic stenosis: a pilot study.

PURPOSE: Ultrasonography of the airway has potential as an alternative, non-invasive, method to monitor patients with subglottic stenosis in an outpatient setting. This prospective, interventional, double-blinded study aimed to correlate ultrasound-based and laryngoscopy-based subglottic stenosis assessment in adults. METHODS: The study was conducted between July 2020 and March 2021 at a tertiary referral center. Consecutive adult patients with subglottic stenosis were evaluated using airway ultrasonography 1 day prior to scheduled laryngoscopy. The radiologist was blinded to the preoperative endoscopic findings, and the primary surgeon was blinded to the ultrasonographic measurements. The intraoperative subglottic diameter was defined as the outer diameter of an endotracheal tube passing through the subglottis without producing an air leak. RESULTS: Sixteen patients (11 females; age range, 17-66 years; mean = 44.06, SD = 12.79) were included. The ultrasonographic subglottic diameter ranged from 5.20 mm to 8.00 mm (mean = 6.24 mm, SD = 0.90). In 15 of 16 patients, the diameter difference between the ultrasonographic and intraoperative measurements ranged from -0.80 mm to 0.30 mm (mean = -0.20 mm, SD = 0.35). However, patient 6 had a difference of - 2.10 mm between the two measurements, which was attributed to thick laryngotracheal secretions interfering with the ultrasonographic air shadow. Data analysis of all 16 patients showed a statistically significant correlation between the readings obtained by the two techniques (r = 0.84, P = 0.000051). CONCLUSION: This study found a significant correlation between ultrasonography-based and laryngoscopy-based subglottic stenosis assessment in adult patients. It provides a basis for an alternative and potentially reliable method to monitor patients with subglottic stenosis.

Correlations of Radiographic and Endoscopic Observations in Subglottic Stenosis.

OBJECTIVE(S): Subglottic stenosis (SGS) represents a constellation of diverse pathologic processes that ultimately lead to narrowing of the subglottic region and can produce significant morbidity. Existing endoscopic and radiographic assessments may not be consistent in practice. METHODS: Severity of stenosis was evaluated and reported using the Cotton-Myer classification system from 33 endoscopic procedures from 32 unique subjects. Radiographic imaging within the preceding 3 month period was subsequently reviewed and narrowing was measured by a blinded radiologist. Degree of stenosis was reported as a percentage in 30 out of 33 endoscopic evaluations and subsequently compared to radiographically determined percentage of stenosis. Statistical analyzes were conducted to evaluate concordance between endoscopic and radiographic assessments. RESULTS: About 45.5% (15/33) of the evaluations were in agreement using Cotton-Myer scoring, while 27.3% (9/33) were discrepant by 1 grade and 27.3% (9/33) by 2 grades. Correlation of degree of stenosis as a percentage using Spearman (coefficient: 0.233, P-value: .214) and Pearson (coefficient: 0.138, P-value: .466) methods demonstrated very weak relationships. Radiographic scoring did not predict endoscopic classification to a significant degree using mixed effects regression. CONCLUSIONS: Radiographic and endoscopic grading of subglottic stenosis may not be reliably concordant in practice.

Three dimensional printed models of the airway for preoperative planning of open Laryngotracheal surgery in children: Surgeon's perception of utility.

BACKGROUND: Preoperative planning of open laryngotracheal surgery is important for achieving good results. This study examines the surgeon's perception of the importance of using life size 3D printed models of the pediatric airway on surgical decision making. METHODS: Life-size three-dimensional models of the upper airway were created based on CT images of children scheduled for laryngotracheal-reconstruction and cricotracheal resection with anastomosis. Five pediatric airway surgeons evaluated the three-dimensional models for determining the surgical approach, incision location and length, graft length, and need for single or double-stage surgery of seven children (median age 4.4 years, M:F ratio 4:3). They rated the importance of the three-dimensional model findings compared to the direct laryngoscopy videos and CT findings for each domain on a validated Likert scale of 1-5. RESULTS: The mean rating for all domains was 3.6 ± 0.63 ("moderately important" to "very important"), and the median rating was 4 ("very important"). There was full agreement between raters for length of incision and length of graft. The between-rater agreement was 0.608 ("good") for surgical approach, 0.585 ("moderate") for incision location, and 0.429 ("moderate") for need for single- or two-stage surgery. CONCLUSION: Patient-specific three-dimensional printed models of children's upper airways were scored by pediatric airway surgeons as being moderately to very important for preoperative planning of open laryngotracheal surgery. Large-scale, objective outcome studies are warranted to establish the reliability and efficiency of these models.

Use of Airway Ultrasound in Infants With Unexpected Subglottic Stenosis During Anesthesia Induction: A Case Report.

Point-of-care ultrasound has been integrated into airway management because it allows for rapid and noninvasive assessments. We present 2 cases of unexpected subglottic stenosis in infants during induction of anesthesia. Intubation failed even with endotracheal tubes that were small for patients' age. Airway ultrasound was used to measure the subglottic airway diameters, which were 2.0 and 3.0 mm in first and second cases, respectively. The severity of subglottic stenosis in the first case was grade III, requiring emergent tracheostomy. In conclusion, airway ultrasound helps to assess possibility of intubation and plan further airway management in children with unexpected difficult airway.

Surgery for laryngotracheal stenosis: Improved results.

OBJECTIVE: Laryngotracheal resection is still considered a challenging operation and few high-volume institutions have reported large series of patients in this setting. During the 5 years, novel surgical techniques as well as new trends in the intra- and postoperative management have been proposed. We present results of our increased experience with laryngotracheal resection for benign stenosis. METHODS: Between 1991 and May 2019, 228 consecutive patients underwent laryngotracheal resection for subglottic stenosis. One hundred eighty-three (80.3%) were postintubation, and 45 (19.7%) were idiopathic. Most of them (58.7%) underwent surgery during the past 5 years. At the time of surgery, 139 patients (61%) had received tracheostomy, laser, or laser plus stenting. The upper limit of the stenosis ranged between actual involvement of the vocal cords to 1.5 cm from the glottis. RESULTS: There was no perioperative mortality. Two hundred twenty-two patients underwent resection and anastomosis according to the Pearson technique; 6 patients with involvement of thyroid cartilage underwent resection and reconstruction with the laryngofissure technique. Airway resection length ranged between 1.5 and 8 cm (mean, 3.8 ± 0.8 cm) and it was >4.5 cm in 19 patients. Airway complication rate was 7.8%. Overall success of airway complication treatment was 83.3%. Definitive success was achieved in 98.7% of patients. Patients presenting with idiopathic stenosis or postcoma patients showed no increased failure rate. CONCLUSIONS: Laryngotracheal resection for benign subglottic stenosis is safe and effective, and provides a very high rate of success. Careful intra- and postoperative management is crucial for a successful outcome.

Quantitative Evaluation of Subglottic Stenosis Using Ultrashort Echo Time MRI in a Rabbit Model.

OBJECTIVE/HYPOTHESIS: To assess the ability of ultra-short echo time (UTE)-MRI to detect subglottic stenosis (SGS) and evaluate response to balloon dilation. To correlate measurements from UTE-MRI with endotracheal-tube (ETT)-sizing and to investigate whether SGS causes change in airway dynamics. STUDY DESIGN: Animal research study. METHODS: Eight adult New-Zealand white rabbits were used as they approximate neonatal airway-size. The airways were measured using ETT-sizing and 3D UTE-MRI at baseline, 2 weeks post-cauterization induced SGS injury, and post-balloon dilation treatment. UTE-MR images were acquired to determine airway anatomy and motion. Airways were segmented from MR images. Cross-sectional area (CSA), major and minor diameters (Dmajor and Dminor ), and eccentricity were measured. RESULTS: Post-injury CSA at SGS was significantly reduced (mean 38%) compared to baseline (P = .003) using UTE-MRI. ETT-sizing correlated significantly with MRI-measured CSA at the SGS location (r = 0.6; P < .01), particularly at the post-injury timepoint (r = 0.93; P < .01). Outer diameter from ETT-sizing (OD) correlated significantly with Dmajor (r = 0.63; P < .01) from UTE-MRI at the SGS location, especially for the post-injury timepoint (r = 0.91; P < .01). Mean CSA of upper trachea did not change significantly between end-expiration and end-inspiration at any timepoint (all P > .05). Eccentricity of the upper trachea increased significantly post-balloon dilation (P < .05). CONCLUSIONS: UTE-MRI successfully detected SGS and treatment response in the rabbit model, with good correlation to ETT-sizing. Balloon dilation increased CSA at SGS, but not to baseline values. SGS did not alter dynamic motion for the trachea in this rabbit model; however, tracheas were significantly eccentric post-balloon dilation. UTE-MRI can detect SGS without sedation or ionizing radiation and may be a non-invasive alternative to ETT-sizing. LEVEL OF EVIDENCE: NA Laryngoscope, 131:E1971-E1979, 2021.

Superior Strategy in Benign Tracheal Stenosis Treatment: Surgery or Endoscopy?

INTRODUCTION: Due to the variations in (laryngeal) tracheal stenosis (TS) patient groups, there is still no consensus on which patient should be treated with endoscopy or surgery. The aim of the present study was to generate an algorithm in the light of the related literature and the data obtained from a clinic where both endoscopic and surgical treatments are conducted. METHOD: A retrospective analysis was performed on the data of a total of 56 patients during 2013 to 2019. A total of 38 patients were subject to surgery with 31 as a first treatment option and 7 due to the unsatisfactory results of endoscopic treatments. Endoscopic approaches were tried on a total of 29 patients with 25 as initial treatment and 4 due to postsurgical recurrence. RESULTS: Symptomatic full control ratio was determined as 69% with endoscopic treatments, 89.5% in subglottic stenosis (SGS) surgery (n = 19), and 89.5% in trachea surgery (n = 19). However, success rates with no recurrence were determined, respectively, as 40.0, 36.4, and 36.4% for patients subject to dilatation, stent, or T tube treatment. Dilatation was observed to be successful in patients with stenotic segment lengths of less than 1.5 cm (p = 0.02). Failure rates increased in SGS (p = 0.03) and TS (p = 0.12) in the surgical group with increasing stenotic segment length. The presence of comorbidities was not effective on treatment success. CONCLUSION: Endoscopic methods are preferred in cases of web-like stenosis. Surgical methods should first be considered for other patients and endoscopic methods should be used on patients who are not suited for surgery or in cases of postsurgical recurrence.

Subglottic Stenosis Position Affects Work of Breathing.

OBJECTIVES: Subglottic stenosis (SGS) is the most common type of laryngeal stenosis in neonates. SGS severity is currently graded based on percent area of obstruction (%AO) via the Myer-Cotton grading scale. However, patients with similar %AO can have widely different clinical courses. Computational fluid dynamics (CFD) based on patient-specific imaging can quantify the relationship between airway geometry and flow dynamics. We investigated the effect of %AO and axial position of SGS on work of breathing (WOB) in neonates using magnetic resonance imaging. METHODS: High-resolution ultrashort echo-time MRI of the chest and airway was obtained in three neonatal patients with no suspected airway abnormalities; images were segmented to construct three-dimensional (3D) models of the neonatal airways. These models were then modified with virtual SGSs of varying %AO and axial positioning. CFD simulations of peak inspiratory flow were used to calculate patient-specific WOB in nonstenotic and artificially stenosed airway models. RESULTS: CFD simulations demonstrated a relationship between stenosis geometry and WOB increase. WOB rapidly increased with %AO greater than about 70%. Changes in axial position could also increase WOB by approximately the same amount as a 10% increase in %AO. Increased WOB was particularly pronounced when the SGS lumen was misaligned with the glottic jet. CONCLUSION: The results indicate a strong, predictable relationship between WOB and axial position of the stenotic lumen relative to the glottis, which has not been previously reported. These findings may lead to precision diagnosis and treatment prediction tools in individual patients. LEVEL OF EVIDENCE: 4 Laryngoscope, 131:E1220-E1226, 2021.

The direct laryngoscopy and rigid bronchoscopy findings and the subsequent management of infants with failed extubations.

INTRODUCTION: There is limited data regarding the role of direct laryngoscopy and rigid bronchoscopy (DLRB) in infants with failed extubations. Pediatric otolaryngologists are frequently consulted to perform DLRB in infants with failed extubations. OBJECTIVE: To determine the DLRB findings in infants with failed extubations and the interventions performed based on these findings. METHODS: A retrospective chart review was performed on infants less than 12 months old undergoing DLRB for failed extubations from January 2013-June 2017 at a tertiary care children's hospital. Data was collected on age, birth weight, perinatal complications, comorbid conditions, number of failed extubations, length of most recent intubation, operative findings, and subsequent interventions, including tracheostomy. Descriptive and comparative analyses were performed. RESULTS: Of the 62 subjects who met study criteria, median age at DLRB was 3.0 months, corrected age was 1.0 months, gestational age was 27.1 weeks, birth weight was 0.97 kg, and number of failed extubations was 2.0. About 80% had respiratory distress at birth requiring intubation, and 76% carried a diagnosis of bronchopulmonary dysplasia (BPD). The median number of days intubated prior to DLRB was 27. Twenty-seven percent of subjects had no significant abnormal findings on DLRB, and 26% had subglottic stenosis. The majority (74%) underwent tracheostomy. Eighteen percent of subjects had an initial intervention for abnormal DLRB finding(s) other than tracheostomy and were able to avoid tracheostomy as a future intervention. Tracheostomy placement was associated with a diagnosis of BPD (RR 1.78, 95% CI 1.02, 3.10), having a birth weight less than 0.71 kg (RR 1.45, CI 1.01, 2.10), and being intubated for 48 or more days prior to DLRB (RR 1.57, 95% CI 1.05, 2.36); it was not associated with the number of failed extubations prior to DLRB. CONCLUSIONS: Infants with failed extubations commonly had abnormal findings on airway evaluation by DLRB. Most children in this population still required tracheostomy placement, but about 20% were able to have an alternate intervention and avoid tracheostomy.

Inyección intralesional de corticoide como tratamiento para la estenosis subglótica idiopática / Intralesional corticosteroid injection for treatment of idiopathic subglottic stenosis

No disponible

Subglottic stenosis due to chronic lymphocytic leukemia / Estenosis subglótica debida a leucemia linfocítica crónica

No disponible

Validation of the Normalized Laryngeal Constriction Ratio in Normal and Disordered Swallowing.

PURPOSE: The timing of laryngeal vestibule closure (LVC) is important for airway protection during swallowing. However, it is unknown whether the extent of LVC contributes to airway protection. The goal of this study is to validate the extent of LVC via a measure called laryngeal constriction ratio (LCR). METHODS: A retrospective analysis of videofluoroscopic swallows was conducted on 38 stroke participants and 40 healthy controls. The LCR was calculated by deriving a size-normalized area of airspace from a 1) maximum closed laryngeal vestibule and a 2) maximum open laryngeal airspace (at rest). Airway invasion severity was derived via the Penetration-Aspiration Scale score. RESULTS: Six hundred forty-nine videofluoroscopic swallows were analyzed. A mixed model analysis revealed a statistically significant mean difference between the normalized laryngeal constriction ratios of healthy individuals (mean (m) = 0.003) versus older dysphagic patients (m = .026) (P = 0.001), quantifying less closure in older patients with dysphagia. Additionally, swallows with airway compromise had a statistically worse LCR when compared to swallows without airway compromise (P = 0.001). CONCLUSION: The normalized LCR might be a valid fluoroscopic surrogate measure for LVC and, furthermore, airway compromise during swallowing. By investigating spatial measurements in the laryngeal vestibule during safe and unsafe swallows, the LCR provides a direction for further research to allow for critical examination of the physiology relating to closure degree in order to precisely detect and treat abnormalities during swallowing. LEVEL OF EVIDENCE: 4 Laryngoscope, 130:E190-E198, 2020.

Slide laryngotracheoplasty for congenital subglottic stenosis in newborns and infants.

OBJECTIVES: Subglottic stenosis is the most common laryngeal anomaly necessitating tracheostomy in early childhood. Crico- and laryngotracheal resection and laryngotracheal reconstruction-usually with autologous cartilage graft implantation-are the most effective treatments. These surgical techniques are obviously challenging in neonatal age and infancy. However, a reconstructive surgery performed at early age may prevent the sequel of complications. METHODS: The authors present their novel surgical method for congenital subglottic stenosis. Seven infants had inspiratory stridor; two of them had to be intubated and one required tracheostomy. Laryngotracheoscopy, CT or MRI revealed subglottic stenosis: Cotton-Myer grade II in one, and grade III in six cases. Slide laryngotracheoplasty was performed before 5 months of age (10-130 days), with a follow-up period of average 36 months (4-80 months). Phoniatry and quality of life questionnaire were used for evaluation of postoperative results. RESULTS: Slide laryngotracheoplasty in the neonatal age made the temporary tracheostomy unnecessary. All babies remained intubated for 3 to 10 days with an uncuffed tracheal tube. After extubation, no dyspnea or swallowing disorder occurred. A subjective quality of life questionnaire, laryngotracheoscopy, clinical growth charts showed satisfactory functional results. CONCLUSIONS: Single-stage slide laryngotracheoplasty might be a favorable solution for subglottic stenosis, even in early childhood. In one step, the airway can be maintained without stenting and tracheostomy. LEVEL OF EVIDENCE: 4 Laryngoscope, 130:E199-E205, 2020.