This is the first study reporting on the incidence and clinical aspects of sudden sensorineural hearing loss (SSNHL) in South Korea. Using Health Insurance Review and Assessment Service data from 2011 to 2015, the monthly incidence of unilateral SSNHL and incidence according to patients’ sex, age, and month of diagnosis were investigated. The monthly incidence of unilateral SSNHL increased over the 5-year study period, with a mean annual incidence of 17.76 cases/ 100,000 of the population. The incidence increased with age, with most patients presenting in their 60s. There was a slight female preponderance, with a male-to-female ratio of 1: 1.35. Most new patients were diagnosed in October, and the fewest in January. In conclusion, this large-scale study indicates that unilateral SSNHL has a higher incidence among the elderly, women, and in autumn (i.e., along with colder weather).

Adhesion is a major complication of endoscopic sinus surgery that may lead to recurrence of chronic rhinosinusitis, necessitating revision surgery. The purpose of this study was to evaluate the effect of hyaluronic acid and hydroxyethyl starch (HA-HES) relative to hyaluronic acid and carboxymethylcellulose (HA-CMC) with regard to anti-adhesion effect. In this multi-center, prospective, single-blind, randomized controlled study, 77 consecutive patients who underwent bilateral endoscopic sinus surgery were enrolled between March 2014 and March 2015. HA-HES and HA-CMC were applied to randomly assigned ethmoidectomized cavities after the removal of middle meatal packing. At the 1st, 2nd and 4th weeks after surgery, the presence and grades of adhesion, edema, and infection were, respectively, examined via endoscopy by a blinded assessor. The incidence and grades of adhesion at the 2-week follow-up were significantly less in the HA-CMC group than in the HA-HES group (p < 0.05). However, with the exception of week 2, there were no significant differences in the incidence or grades of adhesion, edema, and infection between the two groups. When the primary endpoint-the presence of adhesion at the 4-week follow-up-was compared between two groups, the incidence of adhesion in HA-HES group at the 4-week follow-up was 32% and in HA-CMC was 41.3%, indicating that HA-HES was not inferior to HA-CMC in terms of anti-adhesive effect. No severe adverse reactions were noted during the study period. In conclusion, HA-HES is a safe substitutional anti-adhesion agent that has equivalent effect as HA-CMC after endoscopic sinus surgery.