Auditory neuroma Auditory neuroma is one of the more common intracranial tumors, for the bridge cerebellar angle common benign tumors, accounting for 80% ~ 90%. It is more common in middle-aged people aged 30~50 years old, and there are more females than males. Due to tinnitus, deafness and dizziness in the early stage of the disease, it is mostly diagnosed in otolaryngology department at the initial stage. Clinical manifestations: Acoustic neuroma occurs in the internal auditory canal, compressing the cochlear nerve, facial nerve and internal auditory artery of the internal auditory canal. As the tumor grows further, it squeezes the trigeminal nerve, brainstem, cerebellum and posterior cranial nerves, and increases intracranial pressure by blocking the circulation of cerebrospinal fluid. Symptoms and signs in typical cases are in the following order: abnormal cochlear and vestibular function, cerebellar motor disorder, adjacent nerve involvement, increased intracranial pressure, brainstem compression, cerebellar crisis, and so on. (1) Early symptoms: Early stage of acoustic neuroma is when the tumor diameter is <2.5cm. As the tumor compresses the cochlear and vestibular branches of the auditory nerve in the internal auditory canal, early symptoms of cochlear and vestibular dysfunction such as tinnitus, hearing loss, dizziness, and unsteady gait occur slowly. The frequency and severity of these symptoms vary from person to person, from unnoticeable in mild cases, to recurrent vertigo or persistent unsteady gait that may affect daily life. Less common early symptoms include itching or tingling in the ear, numbness of the posterior wall of the external auditory canal, and decreased tearing on the affected side, which are caused by the compression of the intermediate nerve in the internal auditory canal. (2) Symptoms in middle and late stages: The symptoms gradually worsen with the increasing size of the tumor. When the tumor extends to the pontine cerebellar angle and involves the surrounding structures, typical pontine cerebellar syndrome will appear: if the trigeminal nerve is involved, abnormal sensation and numbness of the affected side, and dull or disappearing corneal reflexes will appear; if the tumor obstructs the cerebrospinal fluid circulation, it can lead to hydrocephalus and severe intracranial hypertension; when the tumor compresses the cerebellum, cerebellar dysfunction, such as fine motor disorders of the hands and feet of the affected side, and unstable gait, can appear; if the tumor compresses the brainstem, it can lead to weakening of limb strength and loss of muscle power. If the tumor compresses the cerebellum, it can lead to limb weakness, numbness of limbs, and sensory loss. Tumor enlargement to a certain extent can lead to increased intracranial pressure, headache, nausea and vomiting and other symptoms. Patients may die due to sudden brain herniation. Auxiliary examination: MRI and other imaging examinations are preferred for the diagnosis of acoustic neuroma. If there is residual hearing, audiometry can be performed to compare the efficacy of surgery before and after the operation. (1) MRI: It is the preferred diagnostic method with high specificity and sensitivity. Typical acoustic neuroma is a round or ovoid tumor centered on the internal auditory canal, with slightly low or equal signal on T1 image, high signal on T2 image, and cystic changes or hemorrhage. Enhanced scan shows obvious enhancement of the tumor. (2) CT: The effect of tumor display is worse than that of MRI, and it is mostly used for screening. However, it has certain advantages in showing the enlargement of the internal auditory canal. Audiometry and otological examination: (1) Tuning fork test: manifested as neurogenic deafness. (2) Electrical audiometry: manifested as neurological deafness and negative resonance test, which can be differentiated from other neurological deafness. (3) Brainstem Auditory Evoked Potential Examination (BEPE): It is helpful for early detection of acoustic neuroma. Treatment Options There are three main treatment methods for acoustic neuroma: follow-up observation, microsurgical resection and stereotactic radiation therapy (Gamma Knife). For patients who are older (more than 70 years old) or have limited life expectancy and do not have brainstem compression or hydrocephalus, they can be followed up for observation and regular review of MRI to monitor tumor growth. For elderly patients with tumors less than 3cm in diameter, who are not willing to undergo surgical treatment and are generally in poor physical condition, they can be treated with Gamma Knife, which is also used as an adjuvant treatment for residual tumors after surgery. Generally speaking, the tumor control rate of Gamma Knife is lower than that of surgery, but the safety and facial nerve preservation are significantly better than that of surgery. Surgery is the most effective treatment for acoustic neuroma. With the development of microscopic technology, the rate of complete surgical resection of acoustic neuroma and the rate of preservation of the auditory nerve have been significantly improved. The choice of surgical approach should take into account the size and location of the tumor, the patient's hearing and the operator's experience, and there are three main approaches: posterior suboccipital ethmoidal sinus approach, transvaginal approach and cranial fossa approach. The posterior approach of suboccipital sigmoid sinus is usually used for the tumor protruding into the internal auditory canal and the diameter is larger than 3 cm. During the operation, the tumor is resected as much as possible, and at the same time, the pulling on the brainstem is reduced as much as possible, so as to avoid the damage of the nerves, especially for the protection of the facial nerve, and the monitoring of the facial nerve can be carried out to improve the rate of the preservation of the facial nerve during operation.