Window Coverage and Liquid Biopsy in the First-Line Therapy of Severe Sudden Sensorineural Hearing Loss

Introduction: Based on clinical practice guidelines, the application of corticosteroids as first-line therapy is common. Although SSHL's etiology is primarily idiopathic, hearing loss can result from perilymphatic fistula (PLF). Recent findings show evidence of a spe-cific rate of PLF based on a cochlin- tomoprotein (CTP) detection test. Based on this rate of PLF treatment, the concepts of SSNHL need to be re-evaluated. The present study aimed to evaluate CTP in SSNHL patients and compare pre-surgical and post-surgical pure tone hearing thresholds after round and oval window sealing as first-line treatment. Material and Methods: 30 patients with unilateral SSNHL with pure tone average (PTA) (4 Freq.) of 60 dB or more were enrolled in a prospective study. All patients underwent tympanoscopy for middle ear exploration as first-line treatment. After intraoperative obser-vation of possible PLF all patients obtained middle ear lavage to gain CTP samples for following ELISA-based CTP detection tests. All patients received round window and oval window sealing with fascia. PTA hearing thresholds were analyzed post-surgical 3 weeks after treatment based on 4-frequency bone conduction (BC). Results: Average preoperative pure-tone BC threshold was 97,7 dB compared with 69 dB postoperative BC threshold. Mean BC improved by 20,3 dB after middle ear explora-tion and window sealing. 56% (17 of 30) of patients recovered at least 10 dB. Middle ear cochlin-tomoprotein detection rate was in 70% positive. Conclusion: The combination of early tympanoscopy and inner ear-specific cochlin-tomoprotein as a detection tool for suspected perilymphatic fistula shows evidence of PLF as a key causative in SSNHL.