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.

Prevalence and incidence of idiopathic subglottic stenosis in southern and central Alberta: a retrospective cohort study

Background

Subglottic stenosis (SGS) is a reportedly rare disease that causes recurrent severe airway obstruction. Etiologies reported for SGS include idiopathic, iatrogenic, autoimmune, congenital, and traumatic, with variable ratios among different centres. From empiric observation, southern and central Alberta was hypothesized to have a disproportionate distribution of SGS driven by increased idiopathic SGS (iSGS) compared to previous literature. Identification of causative agents of iSGS will help understand and guide future management options, so this study aimed to characterize the demographics of SGS subtypes, define prevalence and incidence rates of iSGS in southern Alberta, and geographically analyze for clustering of iSGS prevalence.

Methods

SGS patients from Alberta census divisions No. 1–9 and 15 were retrospectively reviewed. Patients were subtyped according to etiology of SGS and characterized. Idiopathic SGS prevalence and incidence was assessed; prevalence was further geographically segregated by census division and forward sortation area (FSA). Significant clustering patterns were assessed for using a Global Moran’s I analysis.

Results

From 2010 to 2019 we identified 250 SGS patients, who were substantially overrepresented by idiopathic patients (80.4%) compared to autoimmune (10.0%), iatrogenic (7.6%), congenital (1.2%), and traumatic (0.8%). The total iSGS prevalence was 9.28/100,000 with a mean annual incidence rate of 0.71/100,000 per year. Significant clustering was observed (Moran’s index 0.125; z-score 2.832; p = 0.0046) and the highest rates of prevalence were observed in southern Alberta and in rural communities heterogeneously dispersed around Calgary FSAs.

Conclusion

In southern and central Alberta, iSGS patients were disproportionately over-represented in contrast to other subtypes with the highest prevalence in southern Alberta. There was a three-fold higher annual incidence compared to previous literature demonstrating the highest rates of disease reported worldwide. Future research aims to expand the geographical scope and to assess for demographic or environmental differences within significant clusters that may contribute to disease pathophysiology.

Level of evidence

III.

Graphical Abstract

Factors Affecting Posterior Glottic Stenosis Surgery Outcomes: Systematic Review and Meta-analysis

OBJECTIVES

To investigate surgical adjuncts (stents) and previous surgeries on outcomes from posterior glottic stenosis (PGS).

METHODS

PubMED/Medline, CINAHL, EMBASE, and Web of Science were searched for publications on adult patients undergoing surgery for PGS. Decannulation and need for additional surgeries were evaluated as outcomes. Linear mixed-effects (with random effects and fixed effects) models were used for multivariate testing.

RESULTS

In total, 516 abstracts were reviewed and 26 articles were considered for systematic review. Of these, 19 articles with 140 pooled patient cases were extracted for meta-analysis. On multivariate meta-analysis analysis accounting for study-specific variation and use of open procedures, prior surgeries were associated with additional surgeries (RR = 3.76 [1.39-3.86], P = .038) and the use of a stent was associated with a lower likelihood of decannulation (RR = 0.42 [0.09-0.98], P = .044).

CONCLUSION

Minimizing repeat surgery is a predictor for avoiding additional future surgeries and use of a stent was correlated with poor outcomes. These 2 findings may assist providers in patient counseling regarding the need for further surgical interventions. Further, this study is the first to compare the efficacy of surgical approaches for the resolution of PGS, and highlights the importance of avoiding repeat procedures and stents for the management of PGS.

Laryngotracheal Mucosal Surface Expression of Candidate Biomarkers in Idiopathic Subglottic Stenosis

OBJECTIVES

Idiopathic subglottic stenosis (iSGS) is an inflammatory process leading to fibrosis and narrowing of the laryngotracheal airway. There is variability in patient response to surgical intervention, but the mechanisms underlying this variability are unknown. In this pilot study, we measure expression of candidate targets at the mucosal surface of the subglottis in iSGS patients. We aim to identify putative biomarkers for iSGS that provide insights into the molecular basis of disease progression, yield a gene signature for the disease, and/or predict a response to therapy.

STUDY DESIGN

In vitro comparative study of human cells.

METHODS

Levels of candidate transcripts and proteins were measured in healthy and stenotic laryngotracheal tissue specimens taken from the mucosal surface in 16 iSGS patients undergoing endoscopic balloon dilation. Pre- and post-operative pulmonary function test and patient reported voice and breathing outcomes were also assessed. Unsupervised clustering was used to define patient subgroups based on expression profile.

RESULTS

Pulmonary function and voice and breathing outcome metrics demonstrated significant post-operative improvement. Transcript levels of αSMA, CCL2, COL1A1, COL3A1, FN1, IFNG, and TGFB1 and protein levels of CCL2, IFNG, and IL-6 were significantly upregulated in stenotic as compared to healthy tissues. Marked heterogeneity was observed in the patterns of expression of candidate markers across individuals and tissue types. Patient subgroups defined by expression profile did not show a statistically significant difference in dilation interval.

CONCLUSION

Pro-inflammatory and pro-fibrotic pathways are significantly upregulated along the mucosal surface of stenotic laryngotracheal tissues, and CCL2 and IFNG merit further investigation as potential iSGS biomarkers.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:342-349, 2021.

Early medical therapy for acute laryngeal injury (ALgI) following endotracheal intubation: a protocol for a prospective single-centre randomised controlled trial

INTRODUCTION

Respiratory failure requiring endotracheal intubation accounts for a significant proportion of intensive care unit (ICU) admissions. Little attention has been paid to the laryngeal consequences of endotracheal intubation. Acute laryngeal injury (ALgI) after intubation occurs at the mucosal interface of the endotracheal tube and posterior larynx and although not immediately manifest at extubation, can progress to mature fibrosis, restricted glottic mobility and clinically significant ventilatory impairment. A recent prospective observational study has shown that >50% of patients intubated >24 hours in an ICU develop ALgI. Strikingly, patients with AlgI manifest significantly worse subjective breathing at 12 weeks. Current ALgI treatments are largely surgical yet offer a marginal improvement in symptoms. In this study, we will examine the ability of a postextubation medical regime (azithromycin and inhaled budesonide) to improve breathing 12 weeks after ALgI. METHODS AND ANALYSIS: A prospective, single-centre, double-blinded, randomised, control trial will be conducted at Vanderbilt Medical Center. Participants will be recruited from adult patients in ICUs. Participants will undergo a bedside flexible nasolaryngoscopy for the identification of ALgI within 72 hours postextubation. In addition, participants will be asked to complete peak expiratory flow measurements immediately postintubation. Patients found to have ALgI will be randomised to the placebo control or medical therapy group (azithromycin 250 mg and budesonide 0.5 mg for 14 days). Repeat peak expiratory flow, examination of the larynx and patient-reported Clinical COPD (chronic obstructive pulmonary disease) Questionnaire, Voice Handicap Index and 12-Item Short Form Health Survey questionnaires will be conducted at 12 weeks postextubation. Consented patients will also have patient-specific, disease-specific and procedure-specific covariates abstracted from their medical record.

ETHICS AND DISSEMINATION

The Institutional Review Board (IRB) Committee of the Vanderbilt University Medical Center has approved this protocol (IRB #171066). The findings of the trial will be disseminated through peer-reviewed journals, national and international conferences.

TRIAL REGISTRATION NUMBER

NCT03250975.

The Value of Dynamic Voice CT Scan for Complex Airway Patients Undergoing Voice Surgery

Introduction:

Dynamic voice computerized tomography (DVCT) is a novel technique that provides additional information to characterize laryngeal function for patients with complex airway history that may alter surgical decisions. The goal of this study was to evaluate the impact of DVCT on decision making for reconstructive voice surgery for a cohort of post-airway reconstruction dysphonia patients.

Methods:

Retrospective chart review at a pediatric tertiary care center for patients with history of complex airway surgery and subsequent reconstructive voice surgery for dysphonia between 2010 and 2016. The study group had a DVCT prior to surgery while the control group underwent surgery without a DVCT. Consensus Auditory-Perceptual Evaluation of Voice (CAPE-V) and pediatric Voice Handicap Index (pVHI) scores were evaluated by the voice clinic team (otolaryngologist, speech therapist) before and after voice surgery.

Results:

Twenty-one patients were analyzed (14 female, 67%) with a mean age (SD) of 14 (4.5) years old. Ninety percent (17/21) had a prior tracheostomy and a mean (SD) of 2.6 (1.3) airway surgeries. Twelve patients (57%) underwent DVCT prior to reconstructive voice surgery. CAPE-V baseline scores were similar between study and controls (means [SE] = 49 [4.6] and 57 [6.0], P = .72). However, scores significantly improved for the study group after voice surgery (mean [SE] = 31 (4.7), P < .0001) while controls did not improve (58 [5.7], P = .99). Baseline VHI scores were similar between both groups: mean (SE) = 54 (5.4) versus 52 (6.2), respectively, P = .99. Postsurgically, VHI scores were also similar between both groups (means [SE]: 46 [7.1] vs 47 [4.5], P = .99). Reconstructive voice surgery for study patients included posterior cricoid reduction (46%), vocal fold medialization/augmentation (46%), and laryngeal reinnervation (7.7%) while all controls underwent a single treatment (vocal fold medialization/augmentation).

Conclusion:

Patients with preoperative DVCT were more likely to have improvement. DVCT appeared to have altered surgical decision making and has allowed tailoring of reconstructive surgery to specific patients’ needs. DVCT could represent an important tool prior to reconstructive surgery to guide the choice of surgical procedures for complex airway patients.

Preliminary Assessment of Dynamic Voice CT in Post–Airway Reconstruction Patients

Objectives

To compare the ability of the dynamic voice computed tomography (CT) scan to characterize laryngeal function in airway reconstruction patients vs bedside endoscopic nasopharyngolaryngoscopy and videolaryngostroboscopy.

Study Design

Case series with chart review.

Settings

Pediatric tertiary care center.

Subjects and Methods

Retrospective case series of children and young adults with a history of complex airway surgeries with subsequent dysphonia. We analyzed clinical data for all patients who underwent an airway reconstruction procedure between January 1, 2010, and April 30, 2016, and also had a dynamic voice CT and bedside endoscopic exam during the same period.

Results

Twenty-four patients were analyzed (4 male, 20 female) with a mean age of 15.1 years (95% confidence interval [CI], 12.9-17.22). Patients had a mean of 2.2 airway surgeries (95% CI, 1.8-2.6), with 62.5% of them being open procedures. Laryngotracheoplasty with a cartilage graft was the most common procedure (40.0%). The pattern of laryngeal closure could be detected in all cases with the dynamic CT scan (n = 24/24, 100%) compared to 87.5% (21/24) with the standard endoscopic examination ( P = .04). The location of gap closure could be detected in all cases (24/24) with the dynamic voice CT while 20.8% (5/24 patients) could not be rated with standard endoscopy/stroboscopy ( P = .02). Dynamic voice CT was able to assess the vertical closure pattern of the glottis 100% (24/24) while it could be detected in 83.3% (20/24) cases with endoscopic study ( P = .04).

Conclusion

Dynamic voice CT shows promise as an additional tool for evaluation of patients with a history of complex airway procedures by providing complementary information.

Treatment options in idiopathic subglottic stenosis: protocol for a prospective international multicentre pragmatic trial

INTRODUCTION

Idiopathic subglottic stenosis (iSGS) is an unexplained progressive obstruction of the upper airway that occurs almost exclusively in adult, Caucasian women. The disease is characterised by mucosal inflammation and localised fibrosis resulting in life-threatening blockage of the upper airway. Because of high recurrence rates, patients with iSGS will frequently require multiple procedures following their initial diagnosis. Both the disease and its therapies profoundly affect patients' ability to breathe, communicate and swallow. A variety of treatments have been advanced to manage this condition. However, comparative data on effectiveness and side effects of the unique approaches have never been systematically evaluated. This study will create an international, multi-institutional prospective cohort of patients with iSGS. It will compare three surgical approaches to determine how well the most commonly used treatments in iSGS 'work' and what quality of life (QOL) trade-offs are associated with each approach.

METHODS AND ANALYSIS

A prospective pragmatic trial comparing the 'Standard of Care' for iSGS at multiple international institutions. Patients with a diagnosis of iSGS without clinical or laboratory evidence of vasculitis or a history of endotracheal intubation 2 years prior to symptom onset will be included in the study. Prospective evaluation of disease recurrence requiring operative intervention, validated patient-reported outcome (PRO) measures as well as patient-generated health data (mobile peak flow recordings and daily steps taken) will be longitudinally tracked for 36 months. The primary endpoint is treatment effectiveness defined as time to recurrent operative procedure. Secondary endpoints relate to treatment side effects and include PRO measures in voice, swallowing, breathing and global QOL as well as patient-generated health data.

ETHICS AND DISSEMINATION

This protocol was approved by the local IRB Committee of the Vanderbilt University Medical Center in July 2015. The findings of the trial will be disseminated through peer-reviewed journals, national and international conference presentations and directly to patient with iSGS via social media-based support groups.

TRIAL REGISTRATION NUMBER

NCT02481817.

Voice and swallowing outcomes for adults undergoing reconstructive surgery for laryngotracheal stenosis

PURPOSE OF REVIEW

Adult laryngotracheal stenosis is a rare, multifactorial condition which carries a significant physical and psychosocial burden. Surgical approaches have developed in recent years, however, voice and swallowing function can be affected prior to treatment, in the immediate postoperative phase, and as an ongoing consequence of the condition and surgical intervention. In this study we discuss: the nature of the problem; surgical interventions to address airway disorders; optimal patterns of care to maximize voice and swallowing outcomes.

RECENT FINDINGS

Studies in this field are limited and focused on surgical outcomes and airway status with voice and swallowing a secondary consideration. Retrospective studies of swallowing have focused on factors such as the duration of dysphagia symptoms following airway surgery and made comparisons between type of surgery, use of stent, and length of swallowing problems. The literature suggests that patients are likely to return to their preoperative diet. There has been a focus on voice outcomes following cricotracheal resection which results in a postoperative decrease in the fundamental frequency. However, study comparisons are limited by the use of inconsistent outcome measures (for both voice and swallowing) which are often not validated, with heterogeneous groups and varying surgical techniques.

SUMMARY

The limited literature suggests that swallowing function is more likely to recover to presurgical status than voice function. Further prospective studies incorporating consistent instrumental, clinician, and patient-reported outcome measurement are required to understand the nature and extent of dysphagia and dysphonia resulting from this condition and its treatment.

Evaluation of Dyspnea Outcomes After Endoscopic Airway Surgery for Laryngotracheal Stenosis

Importance

Endoscopic airway surgery is a frequently used procedure in the management of laryngotracheal stenosis (LTS); however, no established outcome measures are available to assess treatment response.

Objective

To assess acoustics and aerodynamic measures and voice- and dyspnea-related quality of life (QOL) in adult patients with LTS who undergo endoscopic airway surgery.

Design, Setting, and Participants

This case series compared preoperative measures and postoperative outcomes among adult patients who underwent endoscopic airway surgery for LTS from September 1, 2013, to September 30, 2015, at the tertiary care Johns Hopkins Voice Center. Patients were excluded if they did not undergo balloon dilation or if they had multilevel or glottic stenosis. The Phonatory Aerodynamic System was used to quantify laryngotracheal aerodynamic changes after surgery. Final follow-up was completed 2 to 6 weeks after surgery.

Main Outcomes and Measures

The voice-related QOL instrument (V-RQOL), Dyspnea Index, and Clinical Chronic Obstructive Pulmonary Disease Questionnaire were completed before and after endoscopic surgery. Consensus auditory perceptual evaluation of voice, acoustic measurements, and aerodynamic outcomes were also assessed.

Results

Fourteen patients (1 man and 13 women; mean [SD] age, 45.4 [4.3] years) were enrolled. The mean postoperative V-RQOL scores (n = 14) increased from 74.3 to 85.5 (mean of difference, 11.3; 95% CI, 2.2 to 20.3). The mean postoperative Dyspnea Index (n = 14) decreased from 26.9 to 6.6 (mean of difference, -20.3; 95% CI, -27.9 to -12.7); the mean postoperative Clinical Chronic Obstructive Pulmonary Disease Questionnaire scores (n = 9) decreased from 3.2 to 1.0 (mean of difference, -2.2; 95% CI, -3.4 to -0.9). Postoperative mean vital capacity (n = 14) increased from 2.5 to 3.1 L (mean of difference, 0.6 L; 95% CI, 0.3-1.0 L), whereas mean laryngeal resistance (n = 14) decreased from 73.9 to 46.4 cm H2O/L/s (mean of difference, -27.5 cm H2O/L/s; 95% CI, -44.8 to -10.3 cm H2O/L/s) postoperatively.

Conclusions and Relevance

Patients demonstrate statistically and clinically significant improvement in dyspnea-related QOL, whereas a few patients showed a clinically significant improvement in V-RQOL. Dyspnea-related QOL outcomes should be added to airway surgeons' regular assessment of patients with LTS to measure treatment response and inform the decision to perform a second operation, whereas V-RQOL outcomes need additional prospective study with a larger sample size. The Phonatory Aerodynamic System is not an optimal method to quantify changes in laryngotracheal aerodynamics after intervention in LTS.

Effects of voice-sparing cricotracheal resection on phonation in women

INTRODUCTION

Individuals with idiopathic subglottic stenosis (SGS) are at risk for voice disorders prior to and following surgical management. This study examined the nature and severity of voice disorders in patients with SGS before and after a revised cricotracheal resection (CTR) procedure designed to minimize adverse effects on voice function.

METHOD

Eleven women with idiopathic SGS provided presurgical and postsurgical audio recordings. Voice Handicap Index (VHI) scores were also collected. Cepstral, signal-to-noise, periodicity, and fundamental frequency (F₀ ) analyses were undertaken for connected speech and sustained vowel samples. Listeners made auditory-perceptual ratings of overall quality and monotonicity.

RESULTS

Paired samples statistical analyses revealed that mean F₀ decreased from 215 Hz (standard deviation [SD] = 40 Hz) to 201 Hz (SD = 65 Hz) following surgery. In general, VHI scores decreased after surgery. Voice disorder severity based on the Cepstral Spectral Index of Dysphonia (KayPentax, Montvale, NJ) for sustained vowels decreased (improved) from 41 (SD = 41) to 25 (SD = 21) points; no change was observed for connected speech. Semitone SD (2.2 semitones) did not change from pre- to posttreatment. Auditory-perceptual ratings demonstrated similar results.

CONCLUSION

These preliminary results indicate that this revised CTR procedure is promising in minimizing adverse voice effects while offering a longer-term surgical outcome for SGS. Further research is needed to determine causal factors for pretreatment voice disorders, as well as to optimize treatments in this population.

LEVEL OF EVIDENCE

4. Laryngoscope, 127:2085-2092, 2017.

Effects of Balloon Dilation for Idiopathic Laryngotracheal Stenosis on Voice Production

OBJECTIVE

To evaluate the effects of balloon dilation for idiopathic laryngotracheal stenosis on voice production.

METHODS

Retrospective review of 10 female patients with idiopathic laryngotracheal stenosis undergoing balloon dilation. Voice outcomes were evaluated by comparing pre- and posttreatment patient-reported, perceptual, aerodynamic, and acoustic parameters. Complete data sets were not available for all subjects; sample size for each parameter is reported with the corresponding result.

RESULTS

Total Voice Handicap Index (VHI) decreased significantly (22.9 ± 13.5 to 6.8 ± 6.5; n = 8; p = .015), as did glottal function index (7.2 ± 4.9 to 1.5 ± 2.0; n = 6; p = .022). No changes were observed in the GRBAS (grade, roughness, breathiness, asthenia, strain) scale. Changes in aerodynamic parameters were not statistically significant. Percent jitter decreased (1.32 ± 1.37 to 0.60 ± 0.29; n = 7; P = .078), and fundamental frequency range was preserved (507 ± 325 to 612 ± 281; n = 7; P = .309).

CONCLUSIONS

Our sample of patients with idiopathic laryngotracheal stenosis had a mild-moderate dysphonia that improved with balloon dilation. Importantly, adverse effects on voice that can occur with open procedures were not observed. Patient perception of dysphonia improved while fundamental frequency range was maintained and aerodynamic parameters remained within or moved toward the normal range. Larger prospective studies are warranted to further evaluate changes in voice production associated with balloon dilation.