Cholesteatoma is a cystic structure located in the middle ear and mastoid cavity and is not a true tumor. The inner wall of the capsule is compounded with squamous epithelium, and the capsule is filled with exfoliated epithelium, keratinized material, and cholesterol crystals. The outer side of the capsule is closely connected to its adjacent bone wall or tissue by a layer of fibrous tissue of varying thickness. Cholesteatoma damages the surrounding bone wall and expands in all directions due to its compression of the surrounding bone, collagenase, lysosomal enzymes, as well as necrosis factors and prostaglandins produced by the cholesteatoma and the granulation tissue under its capsule. 1, such as the destruction of the adjacent important structures such as the auditory tuberosity, semicircular canal, facial nerve, etc. can produce hearing loss, vertigo and vomiting, facial palsy (crooked mouth and eyes) and other extracranial complications, which seriously affect the quality of life (such as facial palsy patients lead to depression, autism, low self-esteem, such as vertigo patients need someone to take care of their lives, the sky is spinning, vomiting, etc., such as hearing loss patients have poor academic performance, tinnitus and irritability, difficulty sleeping, etc.). 2.If the foci of infection exist in the capsule, the pus will spread along the surrounding weak area, and if it enters the skull, it will produce intracranial complications leading to dizziness and headache, and in serious cases, high fever, life-threatening and even death. 3. If it develops in the direction of postauricular and mastoid, it will produce postauricular abscess or fistula, neck abscess, etc. Pathogenesis: According to the pathogenesis of cholesteatoma, it can be divided into two types: congenital and acquired. The former is due to the development of ectodermal tissue left over from the embryonic period, while the etiology of the latter is unknown. Due to the direct compression of cholesteatoma and the chemicals it releases, it can destroy the surrounding bone and spread inflammation leading to a series of intracranial and extracranial complications. Therefore, the cholesteatoma type middle ear should be treated surgically as early as possible. Clinical features: Long-term persistent pus flow in the ear, with varying amounts of pus. The pus often has a peculiar foul odor. The cholesteatoma may not cause significant hearing loss, even if the auditory bone is partially destroyed, because the cholesteatoma acts as a bridge between the defective auditory bones, resulting in less significant hearing loss. If the lesion or bacterial toxin invades the cochlea, the hearing loss is mixed. On examination, a marginal perforation of the tympanic membrane is seen in the posterior and superior part of the relaxed or tense tympanic membrane. A grayish-white scaly or pea-like amorphous material is visible in the tympanic chamber from the perforation and is oddly smelly. CT examination of the temporal bone can determine the extent of the lesion and guide surgery. Treatment principles Early surgery should be performed for cholesteatoma type otitis media. Currently, modified mastoidectomy or mastoidectomy is more commonly used to completely remove the lesion and prevent complications in order to obtain a dry ear. While completely removing the lesion, the healthy tissues related to the sound-transmitting structures should be preserved as much as possible, and on this basis, tympanoplasty should be performed simultaneously or in a secondary stage to improve hearing. Our department now often uses the German Binger titanium artificial hearing bone for hearing reconstruction.