This study was withdrawn before enrollment due to challenges in participant recruitment. A revised study protocol will be initiated under a new research project.

This study is a prospective, randomized pilot study. To verify an efficacy/safety of the mixed drug injectable delivery vehicle for treating intractable hearing loss. Hearing test, endoscopy of tympanic membrane and CT scans will be conducted after intratympanic treatment for evaluation.

The goal of this clinical trial (pilot study) is to evaluate the Efficacy and Safety of Combined Hyaluronic Acid and Dexamethasone Treatment in Patients with Hearing Loss. The main questions it aims to answer are: • Q1. Verification of safety, • Q2. Therapeutic effect of drug injection on sensorineural hearing loss. Participants will undergo several assessment tests (Verification of adverse effects in the external and middle ear through endoscopy, Confirmation of adverse effects through imaging, Hearing test to check for additional hearing loss, Check if subjective ear fullness persists for more than a week aside from the drug effect). If there is a comparison group: Researchers will compare dexamethasone and hyaluronic acid to verify hearing improvement and safety.

Inclusion Criteria:

• Patients with sudden hearing loss, Meniere's disease, ototoxic hearing loss, and noise-induced hearing loss of 25dB HL at the frequency at which hearing loss occurs as a result of pure tone hearing test
• Patients whose original hearing ability has not been restored with existing standard treatment (oral, intravenous steroids)
• Those who have not participated in clinical trials within 3 months are selected as subjects

Exclusion Criteria:

• Pregnant or lactating women
• When accompanied by lesion, infection, or anatomical deformity of the outer ear, middle ear, or inner ear
• Those with liver disease or metabolic disease or a history thereof
• History of hypersensitivity to indocyanine green or iodine hypersensitivity
• History of ear surgery
• Cases with posterior labyrinth lesions
• Patients with a history of hypersensitivity to the ingredients of this drug
• In addition, serious diseases such as end-stage renal disease, end-stage liver disease, cardiovascular surgery, progressive brain tumor, progressive hemorrhage, and progressive cerebral hemorrhage are included Cases with brain disease and cancer are excluded from the study