bilateral acoustic neuroma surgery

Bilateral acoustic neuroma accounts for about 5% to 8% of the incidence of acoustic neuroma, formerly known as the central type of neurofibrosis, now named Neurofibromatosis II (NF2). NF2 also includes one side of the acoustic neuroma with two types of lesions: neurofibromatosis, meningioma, glioma, schwannomas, vitreous opacity. The former Von Recklinghausen disease or primary neurofibromatosis, now named Neurofibromatosis I (NF1), is mainly characterized by multiple cutaneous neurofibromatosis and milk coffee pigmentation spots on the skin. The study found that both NF1 and NF2 are autosomal dominant, the former abnormal gene is located on chromosome 17, and the latter is located on chromosome 22. Curing disease: Indication 1, bilateral acoustic neuroma is larger, brain stem pressure is obvious, or cause hydrocephalus, consider stage or first stage tumor resection. 2, bilateral acoustic neuroma on one side of a larger volume, a smaller side, can be surgically removed large tumors, if the small side of the tumor is useful for hearing. Continue to observe, or consider stereotactic radiotherapy. 3, bilateral acoustic neuroma on both sides of the small volume (<1,5cm ~ 2cm), hearing useful, can be under the facial nerve and auditory evoked potential monitoring, resection of one side of the tumor; if the surface, auditory nerve function is retained, then staging Lateral tumor resection. Contraindications 1. There is useful hearing on only one side of the bilateral acoustic neuroma. The side tumor has no obvious compression symptoms and the growth is slow. The surgery should be considered. 2, bilateral auditory neuroma advanced brain stem failure. Preoperative preparation Detailed bilateral audiology and facial nerve function tests. Giant acoustic neuroma has caused increased intracranial pressure, and the ventricular continuous drainage is performed in advance 2 to 3 days before surgery. Surgical procedure 1. Make a long incision after the mastoid, from the upper line 5cm down to the neck 4 plane, the barb-shaped incision is also more used, cut the skin, subcutaneous tissue and muscle layer, directly to the occipital scale surface, with automatic retraction The device retracts the incision. Under the upper line, the occipital bone hole is drilled, and the bone window is enlarged according to the size of the tumor: the upper boundary shows the lower edge of the transverse sinus, the lateral side is near the posterior edge of the sigmoid sinus, and down to the foramen magnum. The tumor is huge and can be cut after the atlas Bow, the inner line reaches the midline or exceeds the midline. 2, the tumor treatment of the valve or radial incision of the dura mater, hanging with a wire suspension. Different from the general unilateral auditory nerve sheath tumor surface, auditory nerve and other surrounding structures, attention should be paid during surgery: 1 The tumor is closely intertwined with the surface and the auditory nerve, and the larger tumor often adheres to the brain stem or the cranial nerves of the 9, 10, and 11 brains. Therefore, the total rate of incision is low, careful separation, as far as possible to avoid damage to this important structure; 2 after the dura mater is cut, the cerebellar hemisphere is retracted inward, the adhesion of the tumor to the surrounding important structures is examined, and the possibility of total tumor resection is estimated. If necessary, the posterior wall of the inner ear hole should be ground; 3 the tumor cystectomy should be performed first, and the tumor volume should be reduced. Anyone who has difficulty in adhesion to the cranial nerve and brain stem and who has difficulty in separation should avoid bilateral hearing loss and facial paralysis. Facial paralysis, as well as the poor results of difficulty in swallowing, it is feasible to remove most of the tumor, and the residual tumor is treated with Gamma Knife. 3, Guan skull because of the rich blood supply of such tumors, so the hemostasis should be thorough, and then suture layer by layer. complication 1, local compression and dressing after meningitis is not enough, the formation of pseudocyst, secondary infection. 2, facial nerve injury in the application of microsurgical techniques, this complication has been significantly reduced. 3, brain stem injury surgery directly damage or damage the supply of arteries. 4, 9th, 10 cranial nerve injury. 5, 5, 7 cranial nerve injury caused by corneal ulcer.