Clinical manifestations of auditory neuroma
Auditory neuroma is a common benign intracranial tumor, accounting for 8-12% of intracranial tumors. The peak age of onset is 30-49 years old, with no gender variability and a few are bilateral. It has a long course and the duration of symptoms can range from months to years. The tumor first compresses the cochlear nerve, facial nerve and internal auditory artery in the inner ear canal, and the corresponding clinical symptoms appear. With the growth of tumor, it can squeeze the trigeminal nerve, brainstem, cerebellum and posterior group of cranial nerves, which can lead to the obstruction of cerebrospinal fluid circulation and increase of intracranial pressure.
1. Hearing impairment: Its first symptoms are mostly the irritation or destruction of auditory nerve, such as tinnitus, vertigo, hearing loss or even deafness. Tinnitus is high pitched and continuous, and hearing loss often occurs at the same time;
2. Trigeminal nerve symptoms: numbness, hypesthesia and weakened corneal reflex on the same side. A few patients may have trigeminal neuralgia symptoms;
Facial nerve symptoms: facial muscle twitching, reduced ipsilateral lacrimation, peripheral facial palsy;
4. Brainstem compression symptoms: vertebral fasciculus sign, contralateral limb light paralysis, contralateral hemianesthesia;
5, cerebellar compression symptoms: ipsilateral cerebellar ataxia, gait instability, dysphonia, etc;
6. Posterior cranial nerve compression symptoms: swallowing difficulty, choking and coughing, hoarseness, reduced gag reflex, etc;
7, cranial hypertension symptoms: headache, vomiting, optic papillary edema, etc.
Indications.
1.Small and medium-sized auditory neuroma (tumor maximum diameter <3cm).
2.Auditory neuroma residual after surgery or recurrence after surgery.
3, the patient’s advanced age, there are contraindications to surgery or the patient refuses surgery can also be considered gamma knife treatment.
Contraindications.
With severe trigeminal neuralgia, microsurgical treatment is recommended, because gamma knife treatment is difficult to rapidly relieve trigeminal neuralgia.
Treatment dose.
Radiation dose: The peripheral irradiation dose for auditory neuroma is 12~14Gy, and the central dose is 22~28Gy.
Precautions.
1, six months to one year after gamma knife treatment, the central reinforcement of auditory neuroma is weakened (central necrosis), some tumors have temporary swelling, and the volume may increase. This is a normal pathological change process, as long as the patient’s symptoms are not significantly aggravated, not accompanied by increased intracranial pressure, can continue to follow up, generally judge whether the treatment is effective boundary for 2 to 3 years after gamma knife treatment.
2, Gamma knife treatment after 50% to 60% of small and medium-sized tumors significantly reduced, about 30% of the tumor slightly reduced or maintain the original size. Some of the larger auditory neuromas shrink significantly only 5 years after gamma knife surgery.
Post-operative complications.
1, nausea, vomiting and other symptoms can occur early after treatment.
2, 1% to 2% of patients develop facial nerve damage 4 to 8 months after gamma knife treatment. 1% to 3% of patients develop trigeminal nerve damage symptoms (facial numbness or discomfort).
3.For moderate or large auditory neuroma, about 5% of patients develop traffic hydrocephalus after treatment, requiring ventriculo-abdominal shunt surgery.
4, there are hearing before treatment, some patients may lose their hearing after treatment.
5, a small number of patients with persistent tinnitus after gamma knife treatment.