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548915 research-article 2014

AOR XXX10.1177/0003489414548915Annals ofOtology,Rhinology&Laryngology Kraft et al Reprinted by permission of Ann Otol Rhinol Laryngol. 2015; 124(2):137-142.

Article

Annals of Otology, Rhinology & Laryngology 2015, Vol. 124(2) 137–142 © The Author(s) 2014 Reprints and permissions: sagepub.com/journalsPermissions.nav DOI: 10.1177/0003489414548915 aor.sagepub.com

Using Pulmonary Function Data to Assess Outcomes in the Endoscopic Management of Subglottic Stenosis

Shannon M. Kraft, MD 1 , Kevin Sykes, PhD, MPH 1 , Andrew Palmer, CCC-SLP 2 , and Joshua Schindler, MD 2

Abstract Objective: This study aimed to examine the authors’ experience with endoscopic management of idiopathic subglottic stenosis (iSGS), and to identify pulmonary function test (PFT) values that can be used to quantify outcomes. Methods: Retrospective review. Results: Twenty-five patients with a new diagnosis of iSGS were seen between 2006 and 2012. Median age at surgery was 45.3 years (interquartile range [IQR], 38.5-67.0), and median body mass index was 28.7 kg/m 2 (IQR, 23.5-32.1). Forty-five procedures were performed. Median preoperative stenosis was 56.8% (Cotton-Myer grade 2). The typical stenosis began 15 mm below the true vocal folds and was 12 mm long. Median follow-up was 21.4 months (IQR, 5.1-43.1). For patients receiving multiple dilations, median time between procedures was 23.7 months. Four PFT parameters demonstrated significant improvement after intervention: (1) PEF (absolute change = 2.54 L/s), (2) PIF (absolute change = 1.57 L/s), (3) FEV1/PEF (absolute change = 0.44), and (4) FIF50% (absolute change = 1.71 L/s). PIF was the only parameter affected by using a larger balloon ( P = .047). Conclusion: PEF, PIF, FEV1/PEF, and FIF50% improved significantly after endoscopic incision and dilation of iSGS, and this could potentially be used as a metric by which to evaluate outcomes in the endoscopic management of subglottic stenosis.

Keywords endoscopic, idiopathic subglottic stenosis, pulmonary function test

Introduction Etiology/Pathophysiology

Ultimately a disease of the subglottic lamina propria, no single etiologic factor has been identified.

Idiopathic subglottic stenosis (iSGS) is a nonspecific fibro- inflammatory process that results in progressive narrowing of the airway at the level of the cricoid and proximal tra- chea. Investigators have proposed a multitude of theories as to the etiology of the process since its first description in 1972. 1 The disorder occurs almost exclusively in women, typically presenting in the fourth or fifth decade. 2 This female preponderance led to the hypothesis that estrogen might play a role in the pathogenesis of iSGS, although the evidence for this has not borne out. 3,4 Current theories regarding the etiology of iSGS have focused on non-gender-specific causes. Subglottic injury from laryngopharyngeal reflux (LPR) has been implicated as a possible cause. 5 Autoimmune disease, specifically a limited form of seronegative polyangiitis with granuloma- tosis (GPA), has also been proposed as a mechanism for iSGS. 6 Other theories on the etiology of the disorder include repetitive microtrauma from cough 7 and hereditary factors. 8

Endoscopic Management of iSGS Although segmental resection of the diseased portion of the airway is considered the gold standard for obtaining long-term improvement in the airway in iSGS, it is a potentially morbid procedure. 9 Endoscopic surgery pro- vides an attractive alternative that is less invasive, albeit less definitive. As surgeon experience has grown, several variations in technique have been explored. Dedo and 1 Department of Otolaryngology, University of Kansas, Kansas City, Kansas, USA 2 Department of Otolaryngology, Oregon Health and Science University, Portland, Oregon, USA Corresponding Author: Shannon M. Kraft, MD, Department of Otolaryngology–Head and Neck Surgery, University of Kansas Medical Center, 3901 Rainbow Boulevard, MS 3010, Kansas City, KS 66160, USA. Email: skraft3@kumc.edu

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