cerebellopontine angle meningioma
Introduction
Brief introduction of cerebellopontine meningioma The cerebellopontine angle meningioma includes tumors that originate behind the rock bones or invade the cerebellum, but do not contain meningiomas that originate from the slope. Many asymptomatic meningiomas are mostly found by chance. Multiple meningiomas are occasionally visible, and there are reports of family history in the literature. 50% is located beside the sagittal sinus, and the other is convex, and the cerebral palsy is more common, followed by the sphenoid ridge, saddle nodule, olfactory sulcus, cerebellopontine angle and cerebellum, etc., and there are few people growing in the ventricle. Also seen in the epidural. Occasionally, other parts. basic knowledge Sickness ratio: 0.0001% Susceptible people: no special people Mode of infection: non-infectious Complications: meningitis brain stem injury trigeminal neuralgia brain edema
Cause
Causes of cerebellopontine meningioma
Pathogenesis:
The type of tumor is more common in endothelial type and fibrous type. It occurs mostly on the meninges behind the rock bone and inside the inner auditory canal. It is often connected with the upper sinus or the sigmoid sinus. Most of them are spherical nodules, and a few are flat. The blood supply of the tumor comes from the dura mater behind the rock bone, and also from the branch of the anterior cerebellum and the posterior cerebellar arteriole. According to the relationship between the tumor and the internal auditory canal, it is often divided into the internal auditory canal and the internal auditory canal. After the group.
Prevention
Cerebellar pons
Surgical resection is still the only effective method. Surgery is mostly performed under the occipital craniotomy, and the cerebrospinal fluid is released during the operation, so that the cerebellum does not need to be excessively pulled. The posterior group is easy to expose and protect the cranial nerve, and exposes the cerebellar incision, the midbrain, the basilar artery and the III. The cranial nerves are similar to the underarms. Sometimes the subtalar approach and the suboccipital approach can be used in combination to make the tumor more fully exposed and provide more favorable conditions for the total tumor. The underarm approach cuts the cerebellum, the field is wider, the basilar artery, III, IV, V brain nerves show more clearly, but this approach will cause brain damage and Labbe vein injury, severe postoperative epilepsy and hemiplegia .
Complication
Complications of cerebellopontine meningioma Complications meningitis brainstem injury trigeminal neuralgia cerebral edema
If surgery is performed, the following complications may be combined after surgery:
1. Meningitis: Post-cranial fossa tumors are more likely to develop meningitis after surgery than other parts of the tumor, mostly occurring about 1 week after surgery, patients continue to have high fever, neck resistance, cerebrospinal fluid leukocytosis, especially in the middle The number of lobular nucleated cells is obvious, but the repeated bacterial culture is negative. The elderly may have symptoms and signs that are not as obvious as those of young adults, but once they deteriorate, the prognosis is very poor. Therefore, patients with craniotomy of the posterior cranial fossa, especially the pons In patients with meningioma in the cerebellar horn area, early, repeated, slow and appropriate amount of lumbar puncture to release cerebrospinal fluid is beneficial to promote the recovery of cerebrospinal fluid circulation and reduce the occurrence of meningitis. In addition, the operation time should be shortened as much as possible, and tumor residuals should be reduced. Washing the cavity, preventive application of antibiotics after surgery are the key to prevent meningitis. Once meningitis occurs, it needs to be actively treated, replace effective antibiotics, release lumbar puncture for multiple lumbar puncture, or lumbar puncture drainage. Intrathecal injection of gentamicin is feasible.
2. Posterior group of cranial nerve injury: If the patient's posterior group is subjected to traction, clamping or post-operative adhesion, the postoperative patient is prone to drinking water, cough, hoarseness, cough reflex, etc. At this time, the patient is prone to inhalation. Pneumonia, patients with postoperative dysfunction are more likely to occur. Once this complication occurs, it can prevent gastric tube feeding, intravenous infusion to ensure the patient's energy and maintain water and electrolyte balance, give nutritional neuropharmacological treatment, and promote neurological function of patients. Recovery, usually care should pay attention to more turn over, take back and so on to promote sputum discharge, once aspiration pneumonia, should try to suck out the food in the inhaled trachea, atomize the diluted sputum, if necessary, cut the trachea, replace the effective antibiotics.
3. Brain stem injury: If the brain stem is excessively pulled during the removal of the tumor, and the brainstem of the brain is excessively electrocautery, or the brain is directly electrocauterized, it may lead to hemiplegia and even respiratory and dysfunction. This complication should be Prevention is the main, if the targeted treatment, respiratory dysfunction patients have a poor prognosis, if only transient brain stem edema, the function may be restored, if the infarction is difficult to recover, for brain stem injury Effective treatment measures, edema should use dehydration drugs, sometimes hyperbaric oxygen can promote functional recovery, acupuncture also has a certain effect, limb dryness caused by brain stem injury, conservative treatment should pay attention to prevent venous thrombosis, especially lower extremity deep vein thrombosis The formation of this complication should also be based on prevention. After the operation, targeted treatment should be carried out for the limbs of the sputum, such as passive activities, massage, physical therapy, acupuncture and anticoagulation.
4. Trigeminal nerve, facial nerve injury often occurs with dystrophic corneal ulcer or exposed keratitis. The occurrence of this complication has a great relationship with the operation. It usually occurs about half a year after surgery. The patient cannot close or the cornea due to long-term eyelids. The weakening of reflex causes keratitis and even the occurrence of corneal ulcer. The key to prevention and treatment is prevention. Postoperative patients should have timely treatment of corneal reflex or peripheral facial paralysis to prevent or delay the occurrence of keratitis and corneal ulcer. Patients should use chlorine for a long time. Oral eye drops or erythromycin eye ointment to maintain corneal nutrition and suture the eyelids if necessary.
5. Cerebral edema: cerebral edema is prone to postoperative meningioma, and cerebral cerebral cerebral horn meningioma is no exception. Once it occurs, it should be given a drug to relieve brain edema.
6. Tumor recurrence: Because the tumor is not completely removed by surgery, or the base of the tumor is not treated and the skull is eroded by the tumor. For patients with incomplete tumor resection, radiotherapy or internal radiotherapy should be performed. Once the tumor recurs, Should still be treated surgically.
7. Other organ lesions: If the patient has heart, lung or other systemic diseases before surgery, multiple organ failure may occur after surgery. The key to prevention and treatment of this complication is prevention. The patient's ability to tolerate surgery is fully estimated before surgery. Surgery can be performed before adequate preparation.
Symptom
Cerebellar pons and meningioma symptoms Common symptoms Increased intracranial pressure, severe pain, dizziness, neuralgia, hoarseness, corneal reflex, dull facial numbness, hearing loss, nystagmus, cough
Symptoms may vary slightly due to differences in growth site, extent of expansion, and compensatory function, but the most common symptoms are V, VII, VIII cranial nerve damage and cerebellar dysfunction, as the tumor grows, cerebellum, brainstem Due to the compression of the tumor, the corresponding symptoms appear. Later, due to the aqueduct, the fourth ventricle is compressed, the cerebral cerebral horn pool and the ring pool are blocked, and the intracranial pressure is increased. Only a few patients show trigeminal neuralgia, or intracranial Increased pressure with mild cerebellar symptoms.
Cerebral nerves are most common with auditory nerve damage, and the affected side suffers from hearing loss and early tinnitus accounted for more than 90%. Dizziness is rare, vestibular function tests and electrical audiometry can detect abnormalities, followed by mild facial nerve damage; diseased lateral tendon or The hemifacial spasm is mostly early manifestation, and some reports have accounted for about 68%.
Trigeminal nerve damage is also more common, patients with side numbness, decreased sensation, corneal reflex or disappear; if the trigeminal nerve branch is affected by diaphragmatic atrophy, individual cases suffer from paroxysmal pain in the lateral or tongue, single The degree of pain is difficult to distinguish from secondary trigeminal neuralgia.
More commonly damaged are the glossopharyngeal nerve and vagus nerve, swallowing and coughing, hoarseness, examination to see that the pharyngeal reflex is weakened or disappeared, soft palate drooping or sputum weakness, and the nerve, sublingual and accessory nerve damage in the cerebellopontine angle Less common in meningiomas.
Cerebellar dysfunction is a common symptom secondary to auditory nerve damage. It is characterized by unstable walking and ataxia of the affected limb, and large horizontal nystagmus. It is rare to have a speech disorder. When the tumor is heavily compressed, the brain stem may appear. The muscle strength of the ipsilateral limb is weakened, and a small number of patients are accompanied by a shallow sensation of the diseased side. Later, bilateral pyramidal tract signs may occur.
Examine
Examination of cerebellopontine meningioma
1. Cerebral angiography: The anterior image can show that the posterior cerebral artery and the superior cerebellar artery are displaced inward. When the tumor develops to the slope, the basilar artery bifurcation shifts to the contralateral side, and the lateral position is like the posterior cerebellar artery. Displacement, at the same time visible tumor staining.
2. CT and MRI scan: the tumor volume is generally larger (more than 3.5cm), located at the cerebellopontine angle of the bridge, connected to the rock bone by the broad base, the boundary is clear, the oval is round, the base is wide, and the density is not high when it is not enhanced. Uniformity, uniformity after injection of contrast agent, calcification or bone destruction or hyperplasia of the bone, the tumor is not centered on the internal auditory canal, the internal auditory canal does not generally expand, and often has adhesion to the cerebellum, and the coronary scan is more Can confirm the relationship between tumor and cerebellum, in MRI images, tumor signal is similar to gray matter, T1 weighted image is low, equal signal, T2 weighted image is equal, high signal; intratumoral calcification or cystic change, tumor There are many edema around, and the relationship between the tumor and the surrounding shows more clear, which is extremely beneficial for the development of surgical plans.
Diagnosis
Diagnosis and diagnosis of cerebellopontine meningioma
diagnosis
Patients gradually develop progressive cerebral cerebellopontine angle syndrome with symptoms of increased intracranial pressure, especially the first non-auditory neurological symptoms, combined with imaging examinations such as CT and MRI, can generally make a diagnosis.
Differential diagnosis
1. Auditory schwannomas: Symptoms are similar to those of cerebral cerebellopontine meningioma. Generally, the symptoms of sphincter sphincter are mostly from the auditory nerve. The internal auditory canal is enlarged and destroyed. The sphincter tumor is more common in men, while meningioma is more in women. Auditory nerve symptoms or damage, rock bone tip destruction, accompanied by nearby calcification, first consider meningioma, auditory schwannomas CT and MRI examinations show round or lobulated low-density lesions, clear boundaries, a few slightly higher density The inner auditory canal is mostly conical or funnel-shaped, and the fourth ventricle is deformed by pressure and displaced or locked to the opposite side. The aqueduct, the third ventricle, and the lateral ventricle are enlarged. After the enhancement, there is obvious enhancement, cystic or necrotic part. There are low-density areas of varying sizes, and MRI examinations show long T1 and long T2 signals.
2. cerebellopontine angle cholesteatoma: multiple manifestations of trigeminal neuralgia or cerebellopontine angle syndrome, younger age, longer course, more damage to the brain, X-ray film shows a small number of bridge cerebellar cholesteatoma visible rock The tip or rock bone is destroyed, and the inner auditory canal is not enlarged; the typical manifestation of CT is low density shadow, the contrast agent is generally not enhanced, the MRI is lower in the T1 weighted image signal, and the signal is higher on the T2 weighted image, and the internal The signal is not uniform. Because the cholesteatoma grows like a sputum, the orthotopic structure is wrapped rather than moved, and no abnormal contrast enhancement occurs.
3. Primary trigeminal neuralgia: Symptoms are paroxysmal severe pain in the localized trigeminal nerve distribution area, generally no abnormal signs, X-ray plain film, CT and MRI no abnormal findings.
4. Brain arachnoiditis: There is a history of infection, fluctuations in the course of the disease, in addition to the limitations of symptoms often have some more diffuse signs, cerebrospinal fluid has inflammation changes, anti-inflammatory treatment has a certain effect.
