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.

Proposal for a Core Outcome Set of Measurement Instruments to Assess Quality of Voice in Adductor Spasmodic Dysphonia Based on a Literature Review.

OBJECTIVES: Uniform evaluation of treatment effect on the quality of voice in adductor spasmodic dysphonia (AdSD) is challenging due to the broad variety of available outcome measurement instruments (OMIs). The European Laryngological Society categorized five types of measurement domains for voice quality evaluations: patient-reported outcome measures, perceptual analyses, acoustic analyses, visual analyses, and aerodynamic measurements. The aim of this study was to propose a core outcome set (COS) for these domains, enabling systematic assessments of treatment effects on the quality of voice in patients with AdSD. METHODS: The PubMed, Embase, and Cochrane databases were searched for eligible studies published before July 2019. The results were systematically analyzed following the protocol of the COnsensus-based Standards for the selection of health Measurement INstruments/Core Outcome Measures in Effectiveness Trials initiative. The proposed COS is based on the prevalence of OMIs, quality of the included studies, criteria for good measurement properties, and correlations to other OMI domains. RESULTS: A total of 76 articles were included, with nearly all studies and OMIs found to be of moderate or low quality. The 19 studies that reported on the correlation of OMIs demonstrated conflicting results. Appraising the best available evidence, our proposed COS consisted of patient-reported outcome measures (voice handicap index), perceptual measurements (grade, roughness, breathiness, strain, and voice breaks) and acoustic measurements (voice breaks, voice onset time, aperiodicity, and multiparameter algorithms). CONCLUSION: A review of OMIs evaluating treatment effects in AdSD was conducted. Based on this review, a uniform COS was proposed. However, evidence for the selected instruments was limited. Further exploration into the validity and reliability of OMIs for AdSD is recommended.

Adductor spasmodic dysphonia: Botulinum toxin a injections or laser thyroarytenoid myoneurectomy? A comparison from the patient perspective.

OBJECTIVES/HYPOTHESIS: The current gold standard of therapy for adductor spasmodic dysphonia (AdSD) is injection of botulinum toxin A (BTX) in the adductor musculature. A surgical procedure could potentially offer more stable and long-lasting voice quality. In this study, we report the long-term results of endoscopic laser thyroarytenoid (TA) myoneurectomy versus BTX treatment in the same patients with AdSD. STUDY DESIGN: Retrospective case series. METHODS: Between July 2013 and September 2016, a total of 22 patients with AdSD were included. Voice outcomes were measured using the Voice Handicap Index and a Likert-scale patient-reported voice questionnaire. Data were obtained for each patient at four time points: preoperatively with and without BTX and twice postoperatively at 3 months (short term) and 12 months (long term). RESULTS: No statistically significant differences were found between voice outcome after BTX injection and the short- and long-term postoperative voice outcomes for the group as a whole. During postoperative follow-up, 10 of the 22 patients (45%) needed a second procedure after an average of 18 months (interquartile range, 13-22 months) due to recurrence of their original voice problem. CONCLUSIONS: The TA myoneurectomy showed encouraging results, comparable to BTX after follow-up of 12 months for the group as a whole. However, after good results initially, voice deterioration was seen in 45% of the patients who all underwent a second procedure. These preliminary results provide important insights into the value of TA myoneurectomy as a potential definite treatment for a select group of patients with AdSD. Further research might explore long-term results after revision surgery. LEVEL OF EVIDENCE: 4 Laryngoscope, 130:741-746, 2020.