Parasagittal meningioma resection

Parasagittal meningioma refers to the attachment of the tumor base to the superior sagittal sinus wall and the lack of brain tissue between the tumor and the superior sagittal sinus. Its incidence is second only to the convex meningioma of the brain, accounting for 18% to 24.5% of the total number of intracranial meningioma, more common in the elderly. The parasagittal meningioma is mostly located on the side of the sagittal sinus, and a few grow to the sides. The dura mater and skull of the corresponding area are often invaded by the tumor, causing hyperplasia of the skull, sometimes the skull hyperplasia is particularly prominent, and a large bony mass is formed at the top of the skull, which is mistaken for osteoma. Some also cause skull destruction, and even cause skull defects, tumor protrusion, is considered extracranial tumor. Some tumors do not invade the skull and have no bone changes. The blood supply of this type of meningioma is mostly from the internal carotid artery and the external carotid artery, mainly the middle meningeal artery, and the anterior cerebral artery and middle cerebral artery also have branches to participate in blood supply. Sometimes there is a thickening of the scalp, superficial or occipital artery blood supply, resulting in extremely rich blood supply to the tumor, increasing the difficulty of operation. Treatment of diseases: intraventricular meningioma Indication Resection of the parasagittal meningioma is applicable to: After the diagnosis of parasagittal meningioma, surgery should be performed in principle. Contraindications There is no absolute contraindication, such as adhesion to important structures such as the lateral fissure vessels, it is not appropriate to force the whole cut. If the general condition is poor or the vital organs have serious organic diseases, it is necessary to undergo appropriate treatment before surgery. Tumors recur after multiple operations, limb paralysis, unconsciousness is not suitable for surgery. Preoperative preparation 1. Take a skull slice to understand whether there is local hyperplasia or destruction of the skull; whether there is thickening or distortion of the vascular pressure trace leading to the bone hyperplasia or destruction zone, and whether there is a skull change with increased intracranial pressure. 2, angiography, superior sagittal sinus angiography or DSA examination to determine whether the tumor is located on one or both sides of the superior sagittal sinus, the source of blood supply to the tumor and the collateral circulation, whether the superior sagittal sinus is violated or completely occluded. 3, in order to reduce intraoperative bleeding, more than 3 to 5 days before surgery, embolization before surgery. 4, adequate blood preparation, often need more than 2000ml. Surgical procedure 1, scalp incision A horseshoe-shaped flap of the frontal, frontal or occipital portion is placed at the predetermined surgical site, and the tip of the flap reaches the midline or crosses the midline. 2, skull treatment According to the shape of the designed bone flap, the periosteum is cut in a curved shape, and the periosteum is slightly separated from the base side toward the temporal side, and 4 to 6 bone drilling holes can be made. The medial edge of the bone flap is 0.5 to 1 cm from the midline. The bone between the bone holes of the midline is best to be bitten with a rongeur to avoid damage to the sagittal sinus or the superior cerebral vein when using the guide and the wire saw, causing massive bleeding. If the medial side is not enough, the bone should be bitten to the midline to the edge of the sagittal sinus. The exfoliation is first extended to the subcranial epidural space to separate the adhesion, and then the bone flap is inverted. In the process of processing the skull, special attention should be paid to hemostasis from drilling to sawing (cutting) the skull and biting the bone, and reducing the amount of bleeding as much as possible. If free bone flaps are used, bleeding can be significantly reduced. 3, treatment of the dura mater After opening the bone flap, if there is small bleeding in the sagittal sinus, hemorrhoids can be covered with a cotton sponge to stop bleeding. Do not overstress the sagittal sinus wall when hemostasis, so as not to cause the sagittal sinus reflex to cause blood pressure to drop. If there is a sinus wall, it is sutured or repaired. After the dura mater is exposed, the arteries on the dura mater that supply the tumor are sewed one by one or along the blood vessel to be electrocoagulated. The dura mater is cut along the edge of the tumor. If the dura mater is loosely attached to the surface of the tumor, it can be separated by electrocoagulation, and the dura mater is turned to the sagittal sinus side. If the dura mater is extensively infiltrated by the tumor, it will not be separated, but the infiltrated dura mater will be removed together when the tumor is removed. 4, remove the tumor There are two ways to remove the tumor: one method is to turn the tumor from the valgus to the sagittal sinus side. The operation is as follows: find the junction of the tumor and the brain tissue, cut the arachnoid, and find the anterior and posterior and lateral margins of the tumor and the brain tissue. The boundary gap is carefully separated by a cotton piece or a micro-sucker, and the tumor is gradually released from shallow to deep, and the blood supply artery is cut off one by one. If preoperative cerebral angiography has identified the main blood supply artery, it should be treated first. After most of the tumor is free, turn it to the inside, find the tumor attached to the base of the sagittal sinus wall, carefully separate until the normal sinus wall is displayed to prevent tumor recurrence. Another method is to flip the dura mater and first electrocoagulate the tumor at the attachment of the sagittal sinus and free the inner side. Pay attention to find the branch of the anterior cerebral artery supplying the tumor, give the clip, electrocoagulate and cut off, and the separation of the anterior and posterior sides of the tumor remains as described above. After the tumor is completely separated from the brain tissue, the tumor is completely removed. If a side wall or side wall plus the top wall is invaded by the tumor, the dura mater can be repaired after the sinus wall is removed. If the three sinus walls are eroded, the sinus cavity is closed, and the autologous saphenous vein graft can be taken. When the central vein just passes over or is embedded in the tumor surface, special attention should be paid to protecting the vein so as to avoid serious dysfunction such as hemiplegia of the contralateral limb due to the venous return disorder. In order to protect the central vein, the arachnoid membrane can be cut along the veins by microsurgical technique, the vein is carefully removed from the tumor, and then the tumor is divided into two halves, respectively, or the tumor is removed in sections. When there is no risk of damage to the central vein, the tumor is isolated as described above and the tumor is completely removed. There have also been reports of cutting the central vein and waiting until the tumor is resected. 5, close the cranial cavity If no tumor infiltration is seen, the dura mater can be covered and sutured; if a small range of dura mater is infiltrated by the tumor, it needs to be coagulated or defocused laser to carbonize the residual tumor tissue and then suture; if the dura mater is widely eroded, The dura mater is removed together with the tumor, and the defect is repaired with the temporalis fascia or the aponeurotic aponeurosis. If the skull is intact in the bone flap, it will be covered in situ. Partially damaged it is necessary to remove the diseased skull or use high-power laser to kill the intratumoral tumor cells, and then cover the bone flap. When the free bone flap is covered, it can be fixed by bioadhesive bonding. The bone flap is removed if the skull is extensively eroded by the tumor. Whether the skull defect is repaired immediately depends on factors such as the degree of brain damage and the possibility of serious brain swelling after surgery. The flaps were sutured as usual. The surgical residual cavity was placed in a silicone tube for drainage. complication 1, severe brain swelling Mostly due to injury or clipping of large reflux veins. Therefore, attention should be paid to the protection of important reflux veins during surgery. Brain swelling often occurs during surgery or within 1 week after surgery. If dehydration and symptomatic treatment are not controlled, decompressive decompression should be considered to preserve the patient's life. 2, lack of nerve function The cause may be the damage to normal brain tissue or the clipping of the donor artery or the main reflux vein when the tumor is removed. Care should be taken during surgery to avoid the above factors. Cerebral edema can also cause loss of function, but it can be recovered in a short period of time. 3, secondary bleeding in the surgical area The reason is mostly due to incomplete hemostasis or controlled hypotension in the operation, or excessive blood loss. The blood pressure did not rise to the normal level before the cranial cavity was closed, so that the postoperative blood pressure rose, causing the patient to move, and the blood was generated in the operation area. Therefore, after the tumor is removed, the blood pressure of the patient is raised to a normal level, and then the blood is completely stopped. Avoid patient agitation after surgery. 4, seizures Can be due to the original seizures. At the time of surgery, only the tumor was removed without removing the "epileptic foci", or there was no seizure before surgery, and epilepsy was complicated after the operation. Anti-epileptic drugs can be used routinely.