Surgery for tumors in the third ventricle and pineal region via the anterior corpus callosum approach

Curing disease: Indication The third ventricle and pineal region tumors through the anterior corpus callosum are roughly the same as the transfrontal cortical approach, and are suitable for the anterior and middle lesions of the third ventricle, but are not limited by the size of the ventricle, and the tumor is expanded. Both sides of the bilateral lateral ventricle can also pass through this approach. Preoperative preparation 1. The patient has an increased intracranial pressure before surgery. CT or MRI shows that the ventricle is enlarged, and ventricular drainage can be performed 1 to 2 days before the operation. 2. Usually, the ventricle drainage is performed on the forehead or occipital angle of the opposite side of the operation before the craniotomy, and it is removed within 5 to 7 days after the operation. Surgical procedure Flap incision Generally, the flap incision in the right frontal hairline is used. First, in the hairline, cut from the midline to the back of the coronal suture 2cm, bend to the outside 6cm, then turn to the front to cut to the hairline, design 4 skull drilling. 2. Bone formation Usually 4 holes are drilled in the right forehead. In order to make the center line fully visible, 6 holes can be made across the center line. After the bone flap was opened with 4 holes in the right forehead, some bones were still needed to be removed from the medial edge of the bone window to reveal the right margin of the superior sagittal sinus. The bone flap across the midline generally has more blood loss. The bone bridge between the two pairs of bone holes before and after the sagittal sinus should be sawed or bitten open before the bone flap is opened. Immediately after the flap is opened, it is covered with gelatin sponge. The surface of the sagittal sinus to reduce blood loss. If the third ventricle tumor is larger or extends backwards, the hole can be moved back 2 cm so that the last hole is 4 cm behind the coronal suture, but the central vein may be damaged excessively backward. Some authors advocate exposing the entire width of the sagittal sinus to enlarge the exposure, but this will increase the compression or damage of the sagittal sinus. In the operation, the sagittal sinus should not be compressed and pulled for a long time. If the bone window is exposed far away from the midline, the bone edge can be bitten inward with a rongeur. 3. Dural incision The lobes cut the dura mater. Turn over the sagittal sinus side. Be careful not to tear the bridge vein that can be retained. It is usually necessary to cut 1 or 2 veins in front of the coronal suture, which is generally not a problem. However, if you encounter a large drainage vein, you should keep it as much as possible. 10.4 4. Carcass incision Before retracting the right hemisphere from the cerebral palsy, recognize the anatomy to reach the middle of the corpus callosum. The best sign is the imaginary line at the intersection of the sagittal line and the coronal suture to the external auditory canal. This line can pass through the middle or interventricular space of the carcass. If the brain pressure plate is placed too far forward, a large amount of adhesion will be encountered between the two frontal lobes, and there should be little adhesion between the frontal lobes and the cerebral palsy. Sometimes the front central groove can be identified on the inside of the hemisphere, which can be used as the rear end of the carcass. Retracting the right hemisphere, when reaching the lower edge of the cerebral palsy, there is no difficulty in recognizing the midline structure. Because the color of the corpus callosum is white, after the hemisphere is retracted, the iliac artery can be seen walking on the cuff. artery. Use two brain plates to move down inside the hemisphere, until you see a white carcass. Find the periorbital artery on both sides of the midline. When the bilateral periorbital arteries are seen, it is best to coagulate the blood vessels between the two arteries to avoid cutting off the branches of the periorbital artery to the ipsilateral hemisphere. Then use a serpentine fixed retractor to reach the deep part of the incision. Retracted to the sides to reveal the carcass. The incision of the carcass should be limited to the first 1/3 of the carcass, and the incision is 2 to 3 cm long. In patients with hydrocephalus, the corpus callosum is often thin and easy to enter the lateral ventricle. If the ventricles are not enlarged, the carcass can be as thick as 1cm to cut through. The corpus callosum is small, and it can be bipolar coagulated with a blunt dissector at the midline or slightly to the right, or it can be cut longitudinally with a small aspirator. Once the carcass is cut, that is, right into the right ventricle, the main signs are choroid plexus, mound vein, septum and interventricular space, and the tumor in the third ventricle is often seen through the interventricular space. Subsequent surgical procedures are the same as those described above for the second half of the frontal cortex approach. This approach is still widely used internationally. In addition, there is an intermediate suture between the medial line of the carcass and the two transparent compartments, and then separated, and the transsacral intercondylar approach to the top of the third ventricle is performed by cutting the median line of the first half of the carcass vertically downward. , enter the middle seam between the two transparent partitions, the two transparent partitions are respectively attached to the back of the left and right body, and then the two sides of the body are separated by the micro-stripping and the brain pressure plate, and enter the top of the third ventricle to reveal Tumor. 5. Resection of the tumor Once entering the third ventricle, first identify the tumor hardness and vascular richness. Before the tumor capsule is cut, the test puncture should be performed. After the cystic tumor is aspirated, the tumor shrinks and the operating space increases to facilitate the peeling. Hard tumors can be removed by block. Soft tumors can be removed by suction or CUSA. However, tumor-clamps are often used to remove the tumor or the central part of the tumor. The number of surgical resections is determined based on the nature of the tumor biopsy and its adhesion to important structures. After the craniopharyngioma protrudes into the third ventricle, it is closely related to the hypothalamus. It should be operated under the operating microscope to remove the tumor tissue without increasing the important structural damage. For those who have serious adhesion to important structures, it is not necessary to force a total resection. To prevent increased operative mortality and serious complications. The purpose should be to discharge the contents of the cyst, reduce the tumor volume, and restore the cerebrospinal fluid pathway. When dealing with large tumors, when the tumor content is not fully removed and sufficient operation clearance is obtained, do not rush to treat the tumor base or excessive traction. Otherwise, the deep blood vessel tears in the tumor are difficult to control. Meningioma and choroid plexus papilloma originate from the choroid plexus, and the tumor pedicle is relatively small, and both tumors are usually completely resectable. Ependymoma can originate from the ependymal membrane at any location, and should be noted when looking for the base of the tumor. According to the width and boundary of the base part, it is decided whether it should be completely cut. The gelatinous cyst is spherical or ovoid, about 1 to 2 cm in diameter, and is located at the top of the third ventricle. However, it can fill the entire third ventricle, and it is attached to the choroidal tissue, which often enlarges the interventricular space. After opening the wall of the capsule, the contents of the suctioned gel sample can be completely removed. However, when a small number of wall adhesions are difficult to peel off adjacent structures, it is preferred to leave a small wall without reluctance to remove. After the tumor was resected, hemostasis was completely stopped by bipolar coagulation. 6. Guan skull After the tumor is resected, the blood and tissue fragments in the brain should be thoroughly washed, the bleeding should be completely stopped, and the ventricle should be placed continuously. The dura mater is tightly sutured, the bone flap is repositioned, and the suture is layer by layer. complication 1. The vein of the large frontal cortex that flows back into the sagittal sinus should be preserved, because once it is cut, it can cause edema and necrosis of one frontal lobe, which leads to hemiplegia. 2. The 1/3 incision in the anterior aspect of the corpus callosum usually has no obvious dysfunction. It can cause some information transfer damage and memory disturbances in the hemisphere. Most of them are temporary and can be recovered within a few weeks. However, the serious damage of the Qianlong is mostly persistent. .