Utility of Routine Spirometry Measures for Surveillance of Idiopathic Subglottic Stenosis

Impact of Procedural Variation in Endoscopic Dilation for Idiopathic Subglottic Stenosis

OBJECTIVES

A small number of Idiopathic subglottic stenosis (iSGS) patients are treated at institutions across the country. Divergence in operative techniques for endoscopic dilation (ED) of iSGS has been anecdotally recognized but not formally characterized. Additionally, the relationship between procedural variation and clinical outcome has not been studied.

METHODS

Secondary analysis of the NoAAC iSGS1000 cohort investigated variation in procedural techniques and treatment outcomes in patients treated with ED across high-enrolling treatment centers (enrolled >10 patients in PR-02 trial).

RESULTS

Thirteen NoAAC centers each enrolled >10 patients treated with ED for a total of 281 subjects. There was significant variation in procedural details and rate of recurrence among institutions. Hierarchal cluster analysis revealed significant heterogeneity among institutions and clusters in all procedural variables. However, analysis demonstrated a transient delay in disease recurrence in cluster 2 which disappeared with longer longitudinal follow-up. Patient-reported outcome and peak expiratory flow data supported the potential benefit of the technical variation in Cluster 2. Distinct to cluster 2, however, was routine use of adjuvant triple medical therapy (proton pump inhibitor (PPI), antibacterial agent, and steroid inhaler).

CONCLUSIONS

Both outcome and procedural technique vary among centers employing ED to treat iSGS. A transient delay in recurrence was observed among centers that routinely prescribed adjuvant medical therapy (antibiotic, inhaled corticosteroid, and PPI) to iSGS patients after endoscopic dilation, which was further supported by patient-reported data and peak expiratory flow data. Prospective studies are needed to understand the effects of adjuvant medical therapy on recurrence after endoscopic dilation.

LEVEL OF EVIDENCE

4 Laryngoscope, 2024.

[Idiopathic Subglottic Tracheal Stenosis]

Idiopathic subglottic stenosis is a circular scarred narrowing of the airway at the transition from the cricoid cartilage to the trachea. The stenosis is found radiologically and endoscopically at the level of the cricoid cartilage without involvement of the cricoid or tracheal cartilage itself. The disease practically only affects women between the ages of 20 and 60. The same clinical picture occurs in granulomatosis with polyangiitis and less frequently in other autoimmune diseases, where it requires systemic treatment. The clinical picture usually begins insidiously with coughing and sputum production and leads to dyspnoea and a restricted cough. As the course is insidious and the patients are otherwise healthy, the symptoms are often misinterpreted and the diagnosis is delayed. Treatment consists of local measures, ranging from dilatation and laser surgical resection, sometimes with local application of medication to inhibit the proliferation of new scar tissue, to laryngotracheal resection of varying degrees. The disease is located in the border area between the trachea and larynx and the patients are therefore treated by ENT medicine, pneumology and thoracic surgery.

Decision-Making in the Treatment of Idiopathic Subglottic Stenosis: A Survey of Laryngologists

OBJECTIVE

Idiopathic subglottic stenosis (iSGS) is a rare condition involving the subglottic larynx and upper trachea, commonly affecting Caucasian females between 30 and 50 years of age. Despite its homogeneous presentation, clinical management for iSGS is yet to be standardized, leading to variability in outcomes between predominant interventions. In recognition of the heterogenicity in iSGS treatment and the need to improve patient outcomes, this study aimed to survey laryngologists to understand the factors influencing clinical decision-making and the incorporation of new treatment modalities for iSGS.

METHODS

An online survey was sent to 145 academic laryngologists. The survey assessed respondents' professional backgrounds, experience treating iSGS, treatment algorithms, and how various patient factors affect management.

RESULTS

Of the 87 (60%) laryngologists who responded to the survey, the most common clinical assessments were tracheoscopy/bronchoscopy (96.8%) and pulmonary function tests (43.6%). Endoscopic dilation (ED) was the most common primary treatment offered (97.5%): 28.7% of surveyed laryngologists offer SISI as a primary treatment, and 74.7% perform SISI as a planned postoperative treatment. The most common SISI protocol was repeated injections every 4-6 weeks for a series of 1-3 total injections. Notably, 9.2% perform the Maddern procedure. Routine algorithms of care involving surgery were most often based on prior experience and prior patient outcomes (75.9%) and conversations with colleagues (64.4%). Only 31% report using the same protocol learned during their fellowship training.

CONCLUSION

This survey highlights significant variation in the management of patients with iSGS. Understanding the factors that influence decision-making may lead to potential standardization in heterogeneous treatment approaches and may improve clinical outcomes.

LEVEL OF EVIDENCE

5 Laryngoscope, 134:865-872, 2024.

Association between Estrogen Exposure and Idiopathic Subglottic Stenosis

OBJECTIVE

Idiopathic subglottic stenosis (iSGS) is a rare, recurrent, fibroinflammatory disease affecting the larynx and proximal trachea. Given it occurs primarily in adult females, estrogen is speculated to play a central pathophysiological role. This study aimed to evaluate relationships between estrogen exposure, disease progression, and recurrence.

METHODS

North American Airway Collaborative (NoAAC) data of adults with iSGS obstructive airway lesions, who underwent index endoscopic airway dilation, were used to identify associations between estrogen exposure, disease characteristics, and time to recurrence (TTR), and interventions were analyzed using Kruskal-Wallis test and Pearson coefficient. Cox proportional hazards regression models compared hazard ratios by estrogen exposure. Kaplan-Meier curves were plotted for TTR based on menopausal status.

RESULTS

In all, 533 females had complete estrogen data (33% premenopausal, 17% perimenopausal, 50% postmenopausal). Median estrogen exposure was 28 years. Overall, there was no dose-response relationship between estrogen exposure and disease recurrence. Premenopausal patients had significantly shorter time from symptom manifestation to diagnosis (1.17 vs. 1.42 years perimenopausal vs. 2.08 years postmenopausal, p < 0.001), shorter time from diagnosis to index endoscopic airway dilation (1.90 vs. 2.50 vs. 3.76 years, p = 0.005), and higher number of procedures (1.73 vs. 1.20 vs. 1.08 procedures, p < 0.001).

CONCLUSIONS

We demonstrate premenopausal patients may have a more aggressive disease variant than their peri- and postmenopausal counterparts. However, it is unclear as to whether this is related to reduced estrogen in the peri- and postmenopausal states or the age-related physiology of wound healing and inflammation, regardless of estrogen.

LEVEL OF EVIDENCE

3 Laryngoscope, 134:825-830, 2024.

Murine Model of Airway Fibrosis has Anatomic, Physiologic, and Molecular Congruency to Human iSGS

OBJECTIVE

To narrow knowledge gaps in the pathophysiology of idiopathic subglottic stenosis (iSGS) through comparison of a murine subglottic stenosis model with iSGS.

STUDY DESIGN

In vivo animal study.

SETTING

Academic institution.

METHODS

Murine samples/measurements were obtained from mice that underwent chemomechanical injury with a wire brush and bleomycin. Human samples/measurements were obtained from iSGS patients. Anatomic, physiologic, and epithelial molecular data were collected using histology, human peak expiratory flow (PEF) and murine airway conductance, gene expression analysis with quantitative polymerase chain reaction, and protein analysis with quantitative immunohistochemistry.

RESULTS

Anatomic patterns of scars at the subglottis and proximal trachea seen in the murine model are similar to iSGS patients. Subglottic stenosis (SGS) mice had a decrease (P = .0194) in airway conductance compared to healthy controls, similar to a decrease (P = .0001) in predilation PEF versus postdilation in iSGS patients. There was decreased epithelial gene expression of E-cadherin (ECAD) (P < 0.01), occludin (OCLN) (P < .01), and cytokeratin-5 (CK5) (P < .05) and protein expression of ECAD (H/M: P < .001), OCLN (H: P < 0.05, M: P < .001), and CK5 (H: P < .001, M: P < .01) in murine SGS and iSGS versus controls.

CONCLUSION

The murine SGS model shows anatomic, physiologic, and molecular congruency with human iSGS, making it a reasonable model to investigate iSGS. The molecular similarities in epithelial barrier dysfunction suggest it may best be suited to explore epithelial mechanisms of iSGS and therapies directed at epithelial reconstitution. This model provides a foundation to collect data that will improve understanding of iSGS, and, ultimately, translate into more accurate animal models for future use.

[Functional, Radiological and Endoscopic Diagnostic of Tracheal Diseases]

Diseases of the trachea are rare, while other diseases associated with shortness of breath and pulmonary symptoms are common, which is why the necessary diagnosis and therapy are regularly delayed. At the same time, diseases range from simple scarring stenosis to extensive tumour disease. Patients may be otherwise healthy, suffer from autoimmune disease, or have severe general illnesses, as in tracheotomised patients. Therefore, history and clinical examination provide very important clues to a disease of the trachea. Subsequent diagnostics should be ordered in a reasonable manner and lead to the correct diagnosis and subsequent therapy in a timely manner. Functional, radiological and endoscopic examinations, each with a special focus in experienced hands, avoid duplicate examinations or misinterpretations. Patients are grateful because diseases of the trachea - a central airway that cannot be bypassed - are experienced as life-threatening or at least as severely limiting the quality of life.

Spirometry in laryngotracheal stenosis: a systematic review and meta-analysis

PURPOSE

This study aimed to assess the changes in spirometry parameters or indices after relieving laryngotracheal stenosis (LTS) in adult patients.

METHODS

A systematic review and meta-analysis of studies from PubMed, Scopus, Web of Science, Cochrane Library, and EBSCO databases was conducted for assessing changes in spirometry values after endoscopic balloon dilatation of LTS in adults. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. Relevant data, such as changes in mean spirometry values between preoperative and postoperative interventions, and findings of receiver operating characteristic curve analyses for predicting the need for surgical intervention, were extracted.

RESULTS

Ten studies including 330 patients overall met the inclusion criteria. Significant improvements were observed from preoperative to postoperative mean values of different spirometry parameters and indices. The overall mean differences in peak expiratory flow (ΔPEF), expiratory disproportion index (ΔEDI), and peak inspiratory flow (ΔPIF) were 2.26 L/s (95% CI 2.14-2.38), 27.94 s (95% CI 26.36-29.52), and 1.21 L/s (95% CI 0.95-1.47), respectively. ΔPEF and ΔPIF values increased, while ΔEDI decreased. In predicting the need for surgical intervention, EDI had the highest sensitivity (88%), and forced expiratory volume per second/forced vital capacity had the highest specificity (85%).

CONCLUSION

Spirometry is a valuable tool for assessing patients with LTS. PEF, EDI, and PIF were the most commonly reported spirometry parameters that significantly improved after airway stenosis was relieved.

How can we identify subglottic stenosis in patients with suspected obstructive disease?

PURPOSE

Subglottic stenosis, a rare condition of the upper airway, is frequently misdiagnosed as obstructive lung disease. The aim of this study was to investigate whether subglottic stenosis could be identified and distinguished from asthma and chronic obstructive pulmonary disease (COPD) using spirometry or the dyspnea index (DI).

METHODS

The study population included 43 patients with asthma, 31 patients with COPD and 50 patients with subglottic stenosis planned to undergo endoscopic intervention. All patients completed the DI and underwent dynamic spirometry registering both inspiratory and expiratory volumes and flows, including the expiratory disproportion index (EDI), the ratio of forced expiratory volume in 1 s to peak expiratory flow. One-way analysis of variance assessed the discrepancy of the variables among the study groups, and receiver operating curve (ROC) analysis determined the measurement with the best discriminatory power providing a cutoff value, maximizing both sensitivity and specificity.

RESULTS

The only statistically significant variables differing between all three groups were the EDI and the DI. The EDI showed an excellent area under the ROC curve (0.99, p < 0.001) with a cutoff value of 0.39 (98% sensitivity, 96% specificity), followed by DI (0.87, p < 0.001) with a cutoff score of > 25 (83% sensitivity and 78% specificity).

CONCLUSION

In patients with dyspnea of unknown cause, an increase in EDI should arouse a suspicion of extrathoracic airway obstruction, advocating for further evaluation with laryngotracheoscopy.

Effect of Intralesional Steroid Injections Among Patients with Acquired Laryngotracheal Stenosis Undergoing Endoscopic Balloon Dilation Using Pulmonary Function Tests

Objectives: Laryngotracheal stenosis (LTS) is characterized by an abnormal decrease in the upper airway diameter. The pulmonary function test (PFT) is an effective adjunctive diagnostic tool for upper airway obstruction. LTS can be managed with either open surgery or less invasive endoscopic approaches, among which endoscopic balloon dilation is the main method; this may include concurrent intralesional steroid injection (ILSI), which has the potential of improving the outcomes. However, the effectiveness of ILSI is unclear. We aimed to compare the improvement in PFT parameters among patients with acquired LTS following endoscopic balloon dilation who received and did not receive ILSIs. We also compared the recurrence times and rates between the 2 patient cohorts. Methods: We retrospectively collected data regarding pre- and postoperative PFTs, as well as inter-dilation interval records, obtained between June 2015 and April 2020. Results: We included 34 patients with acquired etiologies. The most common cause of stenosis was intubation (52.9%), followed by trauma (29.4%). Further, 52.9% of the patients received ILSIs. Symptom recurrence was reported in 23 (67.6%) cases, with no significant between-group difference -0.1389 [95% confidence interval (CI): -0.4483, 0.1705]. The mean (standard deviation) duration of the first reintervention was 8.62 (8.00) and 7.38 (3.20) months among patients who did and did not receive ILSIs, respectively (mean difference -1.23, P = .614, 95% CI -6.30, 3.84). Conclusion: Our findings indicated that PFT parameters improved following endoscopic balloon dilation, with forced expiratory volume in 1 second being significantly higher with concurrent ILSI. However, there was no between-method difference in the treatment effectiveness. Additionally, the restenosis recurrence rate was consistent with that reported in the literature.

Impact of Serial Intralesional Steroid Injections on Idiopathic Subglottic Stenosis

OBJECTIVES

Serial intralesional steroid injection (SILSI) has been increasingly used to treat idiopathic subglottic stenosis (iSGS). Prior studies have shown effectiveness, but not in all patients. This multi-institutional study evaluates the effect of SILSI on time to recurrent operation, peak expiratory flow (PEF), and dyspnea.

METHODS

Post-hoc secondary analysis of the North American Airway Collaborative data were performed to evaluate the outcomes of iSGS patients undergoing and not undergoing SILSI. The primary outcome was time to recurrent operation, evaluated using Kaplan-Meier curves and Cox regression analysis. Secondary outcomes were change in PEF and clinical chronic obstructive pulmonary disease questionnaire (CCQ) score. Within patients undergoing SILSI, demographics, time from last procedure, and PEF at initiation of SILSI were evaluated to determine the effect on recurrence.

RESULTS

Two hundred and ninety patients were included, 238 undergoing endoscopic dilation alone and 52 undergoing dilation and SILSI. No differences in baseline characteristics were observed. There was no difference in time to recurrence (hazard ratio: 0.64; p = 0.183). There were no differences in PEF or CCQ across the 2.5-year study period. Among 52 patients undergoing SILSI, PEF at the time of starting SILSI did not affect recurrence (χ2  = 0.09, p = 0.77).

CONCLUSION

Patients undergoing and not undergoing SILSI had similar times to recurrence, PEF, and CCQ. Factors predicting recurrence among patients undergoing SILSI were not identified. These results support a randomized controlled trial with a uniform SILSI protocol to quantify the effects of SILSI on objective and subjective outcomes and help determine which iSGS patients benefit most.

LEVEL OF EVIDENCE

3 Laryngoscope, 133:2255-2263, 2023.

The diagnostic accuracy of spirometry as screening tool for adult patients with a benign subglottic stenosis

BACKGROUND

There is a considerable diagnostic delay in the diagnosis 'benign acquired subglottic stenosis in adults' (SGS, diagnosed by the reference standard, i.e. laryngo- or bronchoscopy). Patients are frequently misdiagnosed since symptoms of this rare disease may mimic symptoms of 'asthma.' The 'Expiratory Disproportion Index' (EDI) obtained by spirometry, may be a simple instrument to detect an SGS-patient. The aim of this study was to evaluate the diagnostic accuracy of the EDI in differentiating SGS patients from asthma patients.

METHODS

We calculated the EDI from spirometry results of all SGS-patients in the Leiden University Medical Center (LUMC), who had not received treatment 2 years before their spirometry examination. We compared these EDI results with the EDI results of all true asthma patients between 2011 and 2019, who underwent a bronchoscopy (exclusion of SGS by laryngo- or bronchoscopy).

RESULTS

Fifty patients with SGS and 32 true asthma patients were included. Median and IQR ranges of the EDI for SGS and asthma patients were 67.10 (54.33-79.18) and 37.94 (32.41-44.63), respectively. Area under the curve (ROC) of the accuracy of the EDI at discriminating SGS and asthma patients was 0.92 (95% CI = 0.86-0.98). The best cut-off point for the EDI was > 48 (i.e. possible upper airway obstruction), with a sensitivity of 88.0%% (95%CI = 77.2-95.0%%) and specificity of 84.4% (95%CI = 69.4-94.1%).

CONCLUSIONS

The EDI has a good diagnostic accuracy discriminating subglottic stenosis patients from asthma patients, when compared to the reference standard. This measurement from spirometry may potentially shorten the diagnostic delay of SGS patients. Further studies are needed to evaluate clinical reproducibility.

Sirolimus-eluting airway stent reduces profibrotic Th17 cells and inhibits laryngotracheal stenosis

Laryngotracheal stenosis (LTS) is pathologic fibrotic narrowing of the larynx and trachea characterized by hypermetabolic fibroblasts and CD4+ T cell-mediated inflammation. However, the role of CD4+ T cells in promoting LTS fibrosis is unknown. The mTOR signaling pathways have been shown to regulate the T cell phenotype. Here we investigated the influence of mTOR signaling in CD4+ T cells on LTS pathogenesis. In this study, human LTS specimens revealed a higher population of CD4+ T cells expressing the activated isoform of mTOR. In a murine LTS model, targeting mTOR with systemic sirolimus and a sirolimus-eluting airway stent reduced fibrosis and Th17 cells. Selective deletion of mTOR in CD4+ cells reduced Th17 cells and attenuated fibrosis, demonstrating CD4+ T cells' pathologic role in LTS. Multispectral immunofluorescence of human LTS revealed increased Th17 cells. In vitro, Th17 cells increased collagen-1 production by LTS fibroblasts, which was prevented with sirolimus pretreatment of Th17 cells. Collectively, mTOR signaling drove pathologic CD4+ T cell phenotypes in LTS, and targeting mTOR with sirolimus was effective at treating LTS through inhibition of profibrotic Th17 cells. Finally, sirolimus may be delivered locally with a drug-eluting stent, transforming clinical therapy for LTS.

Can the Remote Use of a Peak Flow Meter Predict Severity of Subglottic Stenosis and Surgical Timing?

OBJECTIVE

We aimed to assess the relationship between patient-performed and patient-reported peak flow meter (PFM) measurements with pulmonary function testing (PFT) and Dyspnea Index (DI) scores as a tool for monitoring Subglottic stenosis (SGS) disease progression remotely.

METHODS

Thirty-five SGS patients were prospectively enrolled. Patients were given PFMs to report serial measurements from home. DI scores and PFT were recorded at serial clinic visits. Data were analyzed to determine the correlation between PFM measurements and PFT data. Pre-operative and post-operative PFM measurements, PFT, and DI scores were analyzed for patients who underwent operative intervention. Receiver operating characteristic (ROC) curves were created for PFM measurements, PFT data, and DI scores to predict the likelihood of surgery.

RESULTS

PFM measurements had a "strong" correlation with the peak expiratory flow rate (PEFR), r = 0.78. Means of PEFR, PIFR, EDI, PFM measurements, and DI scores all significantly improved after the operative intervention (p ≤ 0.05). The area under the curve for ROC curves for DI scores, PFM measurements, and EDI were highest in our cohort with values of 0.896, 0.823, and 0.806, respectively.

CONCLUSION

In our SGS cohort, PFM measurements correlate strongly with PEFR measurements. PFM measurements can adequately demonstrate disease progression and predict the need for surgery in this patient population. Together, DI scores and PFM measurements may be a useful tool to remotely follow patients with SGS and inform timing of in-person assessments.

LEVEL OF EVIDENCE

2 Laryngoscope, 133:628-633, 2023.

Monitoring Adult Subglottic Stenosis With Spirometry and Dyspnea Index: A Novel Approach

Objective

The aim was to examine the correlations among the anatomic Cotton-Myer classification, pulmonary function tests (PFTs), and patient-perceived dyspnea or dysphonia in patients with subglottic stenosis and identify measurements accurately reflecting treatment effects.

Study Design

Prospective cohort study.

Setting

Tertiary referral center.

Method

Fifty-two adults receiving endoscopic treatment for isolated subglottic stenosis were consecutively included. Correlations were calculated among the preoperative Cotton-Myer scale, PFTs, the Dyspnea Index (DI), and the Voice Handicap Index. Receiver operating characteristic curves were determined for PFT, DI, and Voice Handicap Index pre- and postoperative measurements.

Results

The Cotton-Myer classification correlated weakly with peak expiratory flow (r = −0.35, P = .012), expiratory disproportion index (r = 0.32, P = .022), peak inspiratory flow (r = −0.32, P = .022), and total peak flow (r = −0.36, P = .01). The DI showed an excellent area under the curve (0.99, P < .001), and among PFTs, the expiratory disproportion index demonstrated the best area under the curve (0.89, P < .001), followed by total peak flow (0.88, P < .001), peak expiratory flow (0.87, P < .001), and peak inspiratory flow (0.84, P < .001). Patients treated endoscopically with balloon dilatation showed a 53% decrease in expiratory disproportion index (95% CI, 41%-66%; P < .001) and a 37% improvement in peak expiratory flow (95% CI, 31%-43%; P < .001).

Conclusion

Expiratory disproportion index or peak expiratory flow combined with DI was a feasible measurement for the monitoring of adult subglottic stenosis. The percentage deterioration of peak expiratory flow and increase in expiratory disproportion index correlated significantly with a proportional percentage increase in DI.

The Value of Dyspnea and Spirometry in Detecting Relapse of Benign Tracheal Stenosis

BACKGROUND

Benign tracheal stenosis may relapse after management.

OBJECTIVES

This study aimed to assess the value of dyspnea and spirometry in detecting relapse of benign tracheal stenosis.

METHODS

Patients with benign tracheal stenosis were evaluated post-management, at regular follow-up and emergency visits, with the Medical Research Council (MRC) dyspnea scale, spirometry, and flexible bronchoscopy. Patient visits were categorized and compared, in terms of change in clinical and functional parameters, in 2 groups: visits with relapse (case group) and visits with no relapse (control group). The ability of the MRC dyspnea scale and spirometry to predict relapse was evaluated.

RESULTS

Thirty-five patients with benign tracheal stenosis were included. Mean follow-up duration was 3.2 years (standard deviation = 3.3). Spirometry data were analyzed from 43 relapse visits (23 patients) versus 90 nonrelapse visits. The MRC dyspnea score and most spirometric indices were associated with relapse. In the receiver operating characteristic analysis, forced expiratory volume in 1 s, forced expiratory flow when 25% of forced vital capacity has been expired, peak expiratory flow (PEF), and total peak flow were superior to the MRC dyspnea score in predicting relapse. Among spirometric indices, >10.8% of PEF reduction has been very sensitive and specific.

CONCLUSIONS

This study supports the role of dyspnea and spirometry in monitoring benign tracheal stenosis, with spirometry predicting relapse even in clinically stable patients. PEF being a very sensitive index has the additional advantage of being assessed by peak flow meter and could potentially be used for remote monitoring.

Pulmonary Function Tests May Better Predict Dyspnea-Severity in Patients with Subglottic Stenosis Compared to Clinician-Reported Stenosis

OBJECTIVE

Patients with subglottic stenosis (SGS) present with varied degree of breathing complaints. The dyspnea index (DI) is a 10-question patient-reported outcome measure designed to measure the severity of upper airway obstruction. We set out to determine whether pulmonary function tests or clinician-reported degree of stenosis best predicted DI scores.

METHODS

Thirty patients with SGS were retrospectively reviewed over a 6-year period. One visit from each patient was included. Data including peak expiratory flow rate (PEFR), body-mass index (BMI), clinician-reported degree of stenosis, and DI scores were reviewed. Multiple linear regression was performed to determine how degree of stenosis and PEFR % predicted the variation in DI score.

RESULTS

PEFR % better predicted DI scores compared to degree of stenosis (partial correlation -0.32 vs 0.17). After stepwise elimination, PEFR % remained in the regression and was significantly associated with DI scores (F[1, 29] = 9.38, P = .005). BMI did not demonstrate a linear relationship with DI scores and was not included in the regression (r = -.02). The PEFR % unstandardized coefficient was -0.25 (95% CI: -0.42 to -0.08, P = .005). The model predicts that a 4% increase in the PEFR % results in a 1-point decrease in the DI score (95% CI: -1.68 to -0.32).

CONCLUSION

This study suggests that pulmonary function tests may be a better in-office measure to substantiate the severity of symptoms in patients with SGS.

Voice-related quality of life: Relation to objective spirometry measures in subglottic stenosis

OBJECTIVES

The current study seeks to identify the correlation between in-office spirometry data and voice-related quality of life in patients with subglottic stenosis (SGS).

METHODS

Patients with SGS of any etiology were included when in-office spirometric data was available in addition to voice-related patient-reported outcomes (PROM) data in the form of the Voice Handicap Index-10 (VHI-10) and/or the Voice-Related Quality of Life (V-RQOL) survey. Overall survey scores and individual question responses were assessed for degree of correlation to spirometric data.

RESULTS

Twenty-nine patients were included in the final analysis. Overall mean total VHI-10 scores totaled 7.15 (SD 9.11), while mean overall V-RQOL scores totaled 78.41 (SD 16.45). Both PEF and PIF rates correlated to total scores on the VHI and V-RQOL surveys. This correlation was stronger with PIF than with PEF, and with the V-RQOL than with the VHI. Questions related to breathlessness most closely correlated with spirometric data.

CONCLUSION

Voice-related QOL is impacted in patients with SGS in a predictable way. Breathlessness while speaking may be more impactful than inability to produce speech in this population.

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.

Modeling Recurrence in Idiopathic Subglottic Stenosis With Mobile Peak Expiratory Flow

OBJECTIVES/HYPOTHESIS

We sought to establish normative peak expiratory flow (PEF) data for patients with idiopathic subglottic stenosis (iSGS), evaluate whether immediate changes in PEF after a procedure predict long-term treatment response, and test if a decline in longitudinal PEF is associated with disease recurrence.

STUDY DESIGN

International, prospective, 3-year multicenter cohort study of 810 patients with untreated, newly diagnosed, or previously treated iSGS.

METHODS

iSGS patients consented and enrolled in the North American Airway Collaborative (NoAAC) iSGS¹⁰⁰⁰ cohort recorded PEF data on a mobile smartphone app. Cox regression tested the associations between the magnitude of postoperative PEF improvement and longitudinal 90-day PEF decline with the risk of disease recurrence.

RESULTS

Within the NoAAC iSGS¹⁰⁰⁰ cohort, 810 patients participated in a 3-year prospective study comparing surgical treatment efficacy and 385 had appropriate PEF measurements and follow-up data. Of those patients, 42% (161/385) required at least one operation during study follow-up. The mean PEF preceding operative intervention was 241 L/min (95% confidence interval [CI]: 120-380) corresponding to a predicted PEF of 52%. The mean increase in PEF following a procedure was 111 L/min (95% CI: 96-125 L/min). Interestingly, the magnitude of immediate PEF improvement was not predictive of disease recurrence (hazard ratio [HR] for 100 L/min increase = 0.90, 95% CI: 0.60-1.00). However, recurrence was associated with the magnitude of PEF decline over 90 days (30% vs. 10% decline, HR = 2.2, 95% CI: 1.5-3.0).

CONCLUSIONS

We provide normative PEF data on a large iSGS patient cohort. The degree of PEF improvement immediately after surgery was not associated with a longer procedure-free interval. However, a 30% decline in PEF over 90 days was associated with elevated risk of disease recurrence.

LEVEL OF EVIDENCE

2 Laryngoscope, 2021.

Endoscopic Resection and Mucosal Reconstitution With Epidermal Grafting: A Pilot Study in Idiopathic Subglottic Stenosis

OBJECTIVE

To describe technical aspects and surgical outcomes of endoscopic resection and mucosal reconstitution with epidermal grafting (ie, the Maddern procedure) in the treatment of idiopathic subglottic stenosis.

STUDY DESIGN

Medical record abstraction.

SETTING

Johns Hopkins Hospital.

METHODS

Retrospective series of 9 adults with idiopathic subglottic stenosis who underwent the Maddern procedure by a single surgeon over a 5-year period. Prespecified outcomes included (1) perioperative outcomes (Clavien-Dindo grade 4/5 complications, need for staged tracheostomy, hospital length of stay), (2) postoperative outcomes (peak expiratory flow rate [PEFR], need for subsequent airway surgery, tracheostomy at follow-up), and (3) patient-reported quality-of-life outcomes (Clinical COPD Questionnaire, Voice Handicap Index-10, Eating Assessment Tool-10, and 12-Item Short Form Version 2). Wilcoxon matched-pairs signed rank test and Kaplan-Meier analysis were performed.

RESULTS

There were no Clavien-Dindo grade 4/5 complications; 2 patients required unplanned staged tracheostomy; and the median length of stay was 3 days. Following endoscopic resection and stent removal, a median of 2 laser resurfacing procedures were required. Two patients developed recurrent stenosis requiring cricotracheal resection (CTR). There were significant improvements in PEFR, Clinical COPD Questionnaire, and Voice Handicap Index-10, without significant difference in Eating Assessment Tool-10. The 12-Item Short Form Version 2 approximated the population norm. Kaplan-Meier analysis demonstrated significant improvement in time to surgery after the final laser resurfacing.

CONCLUSION

The Maddern procedure has a low complication rate and offers durable physiologic improvement in PEFR, limiting need for additional procedures. Risks included need for CTR salvage, temporary tracheostomy, phlegm accumulation, and laryngospasm. It is a surgical option for patients with short dilation intervals who prefer to avoid the risks of CTR.

Impact of Adjuvant Medical Therapies on Surgical Outcomes in Idiopathic Subglottic Stenosis

OBJECTIVES/HYPOTHESIS

Adjuvant medications including proton pump inhibitors (PPI), antibiotics (trimethoprim/sulfamethoxazole [TMP-SMX]), and inhaled corticosteroids (ICS) may be prescribed for patients with idiopathic subglottic stenosis (iSGS). We describe medication use with endoscopic dilation (ED) or endoscopic resection with medical treatment (ERMT) and evaluate impact on outcomes.

STUDY DESIGN

International, prospective, 3-year multicenter cohort study of 810 patients with untreated, newly diagnosed, or previously treated iSGS.

METHODS

Post hoc secondary analysis of prospectively collected North American Airway Collaborative data on outcomes linked with adjuvant medication utilization. Primary outcome was time to recurrent operation, evaluated using Kaplan-Meier curves and Cox regression analysis. Secondary outcomes of change in peak expiratory flow (PEF) and clinical chronic obstructive pulmonary disease questionnaire (CCQ) score over 12 months were compared.

RESULTS

Sixty-one of 129 patients undergoing ED received PPI (47%), and 10/143 patients undergoing ED received ICS (7%). TMP-SMX was used by 87/115 patients (76%) undergoing EMRT. PPI use in the ED group did not affect time to recurrence (hazard ratio [HR] = 1.00, 95% confidence interval [CI]: 0.53-1.88; P = .99) or 12-month change in PEF (L/min) (median [interquartile range], 12.0 [10.7-12.2] vs. 8.7 [-5.1 to 24.9]; P = .59), but was associated with 12-month change in CCQ (-0.05 [-0.97 to 0.75] vs. -0.50 [-1.60 to 0.20]; P = .04). ICS did not affect outcome measures. TMP-SMX use in ERMT did not affect time to recurrence (HR = 0.842, 95% CI: 0.2345-3.023; P = .79), PEF at 12 months (75 [68-89] vs. 81 [68-89]; P = .92), or 12-month change in CCQ (0.20 [-1.05 to 0.47] vs. -0.30 [-1.00 to 0.10]; P = .45).

CONCLUSION

There is no standard practice for prescribing adjuvant medications. These data do not support that adjuvant medications prolong time to recurrence or increase PEF. Patients with iSGS and gastroesophageal reflux disease may experience some symptom benefit with PPI.

LEVEL OF EVIDENCE

Level 3 Laryngoscope, 2021.

Effect of inhaled fluticasone propionate on laryngotracheal stenosis after balloon dilation: a randomized controlled trial

PURPOSE

Laryngotracheal stenosis describes various airflow compromising conditions leading to laryngeal and tracheal narrowing, including subglottic and tracheal stenosis. Direct laryngobronchoscopy is the diagnostic gold standard for laryngotracheal stenosis. This study aimed to explore the effect of inhaled fluticasone propionate as adjuvant medical therapy in patients with laryngotracheal stenosis after balloon dilation.

METHODS

This prospective randomized controlled trial was conducted from April 2019 to April 2020. Fourteen adults (≥ 18 years) with laryngotracheal stenosis consented to participate. All patients underwent endoscopic balloon dilation. Seven patients were treated with inhaled fluticasone propionate, and seven acted as controls. Detailed documentation of operative findings and pre- and post-balloon dilation spirometry measurements were recorded. Basic demographic data and operative details, including information about the percentage of laryngotracheal stenosis, distance of laryngotracheal stenosis from the vocal cords, the stenotic segment vertical length, and the largest endotracheal tube used before and after dilation were noted.

RESULTS

Spirometry measurements were obtained on 34 occasions (17 before and 17 after balloon dilation). The two groups were similar in spirometry values after treatment. Both groups had significantly improved on most spirometry values after balloon dilation.

CONCLUSION

We found that using inhaled steroids after balloon dilatation in patients with laryngotracheal stenosis had no benefit over non-user patients in spirometry parameters during the short postoperative follow-up. To confirm this outcome, we recommend a large-scale double-blind study with a longer follow-up period.

Comparative Treatment Outcomes for Patients With Idiopathic Subglottic Stenosis

Question

What are the outcomes of the 3 most common surgical approaches for idiopathic subglottic stenosis (iSGS)?

Findings

In this cohort study of 810 patients with iSGS who underwent 1 of the 3 most common surgical treatments, 23% of patients underwent a recurrent surgical procedure during the 3-year study period, but recurrence differed by modality (cricotracheal resection, 1%; endoscopic resection with adjuvant medical therapy, 12%; and endoscopic dilation, 28%). Among successfully treated patients, those who underwent cricotracheal resection reported the highest quality of life but the greatest perioperative risk and worst long-term voice outcomes.

Meaning

These results show the feasibility of integrating an engaged rare disease community with a network of surgeons to facilitate rapid and nuanced treatment comparisons; findings may help inform treatment decision-making in iSGS.

Importance

Surgical treatment comparisons in rare diseases are difficult secondary to the geographic distribution of patients. Fortunately, emerging technologies offer promise to reduce these barriers for research.

Objective

To prospectively compare the outcomes of the 3 most common surgical approaches for idiopathic subglottic stenosis (iSGS), a rare airway disease.

Design, Setting, and Participants

In this international, prospective, 3-year multicenter cohort study, 810 patients with untreated, newly diagnosed, or previously treated iSGS were enrolled after undergoing a surgical procedure (endoscopic dilation [ED], endoscopic resection with adjuvant medical therapy [ERMT], or cricotracheal resection [CTR]). Patients were recruited from clinician practices in the North American Airway Collaborative and an online iSGS community on Facebook.

Main Outcomes and Measures

The primary end point was days from initial surgical procedure to recurrent surgical procedure. Secondary end points included quality of life using the Clinical COPD (chronic obstructive pulmonary disease) Questionnaire (CCQ), Voice Handicap Index-10 (VHI-10), Eating Assessment Test-10 (EAT-10), the 12-Item Short-Form Version 2 (SF-12v2), and postoperative complications.

Results

Of 810 patients in this cohort, 798 (98.5%) were female and 787 (97.2%) were white, with a median age of 50 years (interquartile range, 43-58 years). Index surgical procedures were ED (n = 603; 74.4%), ERMT (n = 121; 14.9%), and CTR (n = 86; 10.6%). Overall, 185 patients (22.8%) had a recurrent surgical procedure during the 3-year study, but recurrence differed by modality (CTR, 1 patient [1.2%]; ERMT, 15 [12.4%]; and ED, 169 [28.0%]). Weighted, propensity score–matched, Cox proportional hazards regression models showed ED was inferior to ERMT (hazard ratio [HR], 3.16; 95% CI, 1.8-5.5). Among successfully treated patients without recurrence, those treated with CTR had the best CCQ (0.75 points) and SF-12v2 (54 points) scores and worst VHI-10 score (13 points) 360 days after enrollment as well as the greatest perioperative risk.

Conclusions and Relevance

In this cohort study of 810 patients with iSGS, endoscopic dilation, the most popular surgical approach for iSGS, was associated with a higher recurrence rate compared with other procedures. Cricotracheal resection offered the most durable results but showed the greatest perioperative risk and the worst long-term voice outcomes. Endoscopic resection with medical therapy was associated with better disease control compared with ED and had minimal association with vocal function. These results may be used to inform individual patient treatment decision-making.

Reliability of peak expiratory flow percentage compared to endoscopic grading in subglottic stenosis

OBJECTIVE

To determine the reliability of pulmonary function testing compared to endoscopic grading in the assessment of subglottic stenosis.

METHODS

Consecutively treated patients with subglottic stenosis at a tertiary care specialty hospital from 2009 to 2019 were identified. Two fellowship-trained laryngologists and two otolaryngologists blinded to clinical history reviewed laryngo tracheoscopic examinations and assessed the degree of stenosis using the Cotton-Myer grading system (% stenosis). Nine full flow-volume loops were performed at the time of each exam.

RESULTS

The endoscopic images of 45 subjects were graded for degree of stenosis and the spirometry data were analyzed. The kappa values for Cotton-Myer grade overall was 0.37, grade I was -0.103, grade II was 0.052, and grade III was 0.045. The overall intraclass correlation of the physician grading of estimated percent obstruction (% stenosis) was 0.712 (P < .01) whereas the overall intraclass correlation for PEF% was 0.96 (P < .01). Within each Cotton-Myer grade, the intraclass correlation for % stenosis was 0.45 (P = .02) for grade I, 0.06 (P = .30) for grade II, and 0.16 (P = .03) for grade III. The intraclass correlation for PEF% for grade I was 0.97 (P < .01), grade II was 0.92 (P < .01), and grade III was 0.96 (P < .01).

CONCLUSION

Cotton-Myer grading and estimating percent obstruction (% stenosis) for adult subglottic stenosis showed poor reliability as an assessment tool compared to the excellent intraclass correlation seen with pulmonary function tests within each Cotton-Myer grade subgroup. We recommend pulmonary function testing, specifically PEF% because it is a normalized value, for the assessment and management of subglottic stenosis.

LEVEL OF EVIDENCE

4.

Predicting Need for Surgery in Recurrent Laryngotracheal Stenosis Using Changes in Spirometry

OBJECTIVES/HYPOTHESIS

We sought to identify changes that occur in spirometric values between surgical interventions in patients with recurrent laryngotracheal stenosis and assess the utility of tracking those changes in predicting the need to return to surgery.

METHODS

This is a retrospective, case-control study of laryngotracheal stenosis. Charts from a 10 year period were reviewed, and 80 patients were identified with recurrent laryngotracheal stenosis and serial spirometry. Recorded forced expiratory volume in 1 second (FEV₁ ), forced inspiratory volume in 1 second (FIV₁ ), peak expiratory flow (PEF), and peak inspiratory flow (PIF), and body mass index (BMI) were tabulated. Calculations were then performed to determine deviations in spirometric measurements from maximums. Comparing the patients who required intervention to those who did not, we used a regression analysis to generate a decision tree based on factors with the strongest predictive power. We then calculated receiver operating characteristic (ROC) curves for all calculated variables.

RESULTS

Deviations in PEF, PIF, and FIV₁ from each patient's maximums had strong predictive power in determining return to surgery. PIF was the only fixed measurement found to have a statistically significant role in predicting return to surgery. BMI did not play a role.

CONCLUSION

For each patient, the deviation from their overall spirometric maximums had the statistically strongest predictive power in determining need to return to surgery. This suggests the importance of the trends in spirometric measures for each individual, and implies these trends have greater import than fixed measures alone.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:2199-2203, 2021.

Utility of Spirometry Values for Evaluating Tracheal Stenosis Patients Before and After Balloon Dilation

OBJECTIVES

Tracheal stenosis is defined as a narrowing of the airway distal to the lower edge of the cricoid cartilage. It is initially diagnosed based on clinical presentation and then confirmed using direct laryngobronchoscopy. Other adjunctive diagnostic methods, including spirometry, have been proposed. This study aimed to evaluate the relationship between tracheal stenosis severity and pre- and post-balloon dilatation spirometry parameters in order to assess for significant changes in spirometry values and to evaluate for the effects of stenosis-associated factors on post-dilation spirometry values, including vertical length and grade of the stenosis, as well as the role of wound-modifying agents.

METHODS

This retrospective study included adults (>18 years of age) with isolated tracheal stenosis who underwent endoscopic balloon dilations at King Saud University Medical City from June 2015 to May 2019, with detailed documentation of operative findings and valid spirometry measurements pre- and post-balloon dilation. Basic demographic data and operative note details, including information about the percentage of tracheal stenosis, distance of tracheal stenosis from vocal cords, vertical length of stenotic segment, and use of wound-modifying agents (topical mitomycin C or triamcinolone injections), were extracted.

RESULTS

Fourteen patients with spirometry measurements obtained on 50 occasions (25 pre-balloon dilation and 25 post-balloon dilation) were included. Each 1-unit increase in the vertical length of the stenosis showed a statistically significant negative relationship (-1.47 L/s) with pre-balloon dilation peak expiratory flow (PEF; P = .034). Post-balloon dilation spirometric values showed statistically significant improvements for most variables.

CONCLUSIONS

The vertical length of an isolated tracheal stenosis can be predicted before surgical interventions using PEF values and may be a significant indicator of anticipated post-balloon dilation surgical success. Our study suggested that spirometry is a very useful technique for evaluating patients with tracheal stenosis due to its noninvasiveness, cost-effectiveness, with a good clinical value.

Implementation of Telemedicine in a Laryngology Practice During the COVID-19 Pandemic: Lessons Learned, Experiences Shared

Objectives

The novel coronavirus disease 2019 has posed significant limitations and barriers to providing in-person healthcare. We aim to provide a summary of learned experiences and important considerations for implementing and offering telehealth to provide laryngology subspecialty care during the COVID-19 pandemic and thereafter.

Materials and Methods

Four laryngologists and a voice-specialized speech-language pathologist from a tertiary-care academic Voice and Swallowing Center were engaged in a structured group consensus conference. Participants shared input, experiences, and practice patterns employed via telemedicine (via telephone or video-communication) during the early COVID-19 era.

Results

Key identified areas of consideration when offering telemedicine included (1) how to set up and structure a telemedicine visit and maintain patient confidentiality, (2) patient examination and treatment initiation, (3) optimization of the tele-visit, (4) limitations and recognition of when a tele-visit is insufficient for patient care needs, (5) billing/reimbursement considerations. Group consensus for the aforementioned topics is summarized and discussed.

Conclusion

During the COVID-19 pandemic, a telemedicine model can be effectively employed to improve patient access to subspecialty laryngology care, including a multidisciplinary care approach, with initiation of various therapeutic interventions. A major limitation given the preclusion of in-person assessment is the lack of access to laryngoscopy, which can likely be delayed safely in the majority of individuals.