Surgery for tumors of the third ventricle and pineal region via the posterior transcallosal approach

The posterior tibial approach is the first surgical procedure used for tumor resection in the pineal region. This approach has been used by many scholars to this day. The advantage of this approach is that it does not damage the cerebral hemisphere, so no postoperative epilepsy occurs. The downside is that the surgical site is deep, poorly exposed, and there is a risk of damaging important structures around it and the brain or large veins above it. Microsurgery is applied to deep brain tumor resection, the damage of surgery is reduced, and the therapeutic effect is also obviously improved. Therefore, it is still one of the surgical approaches for tumor resection in this area. Treating diseases: pineal tumors Indication The third ventricle and pineal region tumor surgery through the posterior tibial approach is applicable to: 1. The third ventricle posterior and pineal region radiotherapy is not sensitive to tumors, the nature of which is benign or malignant, and there may be full and major resection. 2. After radiotherapy in this area, the tumor shrinkage is not significant, and the improvement of clinical symptoms is not obvious. 3. After resection of other surgical approaches, the tumor recurred. Contraindications 1. Crossed cerebral dominance, which is the left hemisphere language advantage of the left-lead patient and the right hemisphere language advantage of the right-handed patient, is not suitable for the corpus callosum, which is prone to language problems and/or writing difficulties after surgery. 2. For germ-sensitive germ cell tumors (germino-ma), surgical resection is not preferred. 3. Those who have implanted tumors are not suitable for surgery. 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. 3. Preoperative application of adenosine sodium carotid artery injection to determine the dominant hemisphere of the language center, such as patients with crossed brains, should use other surgical approaches. Surgical procedure Scalp incision The right occipital flap was incision, anterior to central posterior gyrus, medial sagittal midline, posterior to anterior occipital lobe. In order to expand the surgical exposure, Tu Tongjin uses the bone flap of the midline. Therefore, the scalp incision is also from the midline to the opposite side. After the flap is free, turn to the right side of the ankle. 2. Bone craniotomy The top left bone flap is made of 4 to 5 holes. The inner hole is located beside the sagittal sinus. The outer hole is 6 to 7 cm from the midline. The periosteum of the bone flap is turned to the temporal side. The upper edge of the bone window still needs the rongeur. Some bone is removed to reveal the edge of the sagittal sinus. A total of 6 holes were drilled across the midline bone flap of the application, and 2 of them were on the opposite side. This method can achieve greater exposure by retracting the sagittal sinus. The disadvantage is that there is more blood loss when the bone flap is opened, and it is necessary to quickly cover the sponge to stop bleeding. 3. Dural incision The dura mater is cut in the opposite direction to the bone flap and retracted toward the sagittal sinus side by suture. At the sagittal sinus, the bridge vein often adheres to the dura mater, or enters the dura mater too early and re-injects into the sinus. It needs to be carefully stripped or the sneaked dura segment can be retained on the bridge vein to avoid tearing the bridge. vein. To distinguish between the central vein (Rolandic vein) and other bridge veins, the central vein that flows back to the superior sagittal sinus along the central sulcus is thick and can not be damaged or cut. It should be properly covered with cotton sheets, and the brain pressure plate should not be pulled close. Once this vein is damaged, hemiplegia will occur. Recovery is incomplete. Other small portal veins injected into the sinus of the parietal lobe can be severed when the surgical approach is blocked, and larger bridge veins should be preserved if not required for surgery. 4. Carcass incision The cerebral longitudinal plate was inserted along the sagittal sinus and the right side of the cerebral palsy with a brain pressure plate, and the inner side of the parietal lobe was retracted outward. The connected blood vessels between the medial side of the parietal lobe and the cerebral palsy also need to be electrocoagulated and then cut off, and then continue to reach the posterior and compression parts of the corpus callosum. Larger tumors often thin the posterior part of the corpus callosum. Before the carcass was cut, some authors advocated electrocoagulation of the sagittal sinus and incision of the lower half of the cerebral palsy to enlarge the field of exposure. The serpentine fixed retractor is used to retract the inner sides of the parietal leaves on both sides, and the subsequent operation is preferably performed under a surgical microscope. The bipolar electrocoagulation is used to treat the blood vessels of the posterior surface of the corpus callosum across the midline. The corpus callosum itself has few blood vessels. The microscopic stripper is used to cut the corpus callosum 3 to 4 cm in the median line. The thinned corpus callosum is easily cut through, and then enters the top of the third ventricle, and larger tumors can be revealed. 5. Tumor resection Carefully distinguish the anatomical relationship between the tumor and the intracerebral vein and the great cerebral vein above the tumor, and peel the left and right cerebral veins outward from the surface of the tumor, and protect the vein with a small cotton piece with a tail line. Suzuki advocates that the two internal cerebral veins are pulled together to the opposite side, which is considered to be beneficial for revealing the tumor. Before incision of the tumor, the surface blood vessels of the tumor are treated by bipolar coagulation. For example, the cystic tumor can be aspirated to shrink the tumor, and the cotton strip with the tail line is placed between the tumor and the surrounding structure to continue to expand the free range. Then the tumor is removed and the tumor content is removed, or the benign tumor is removed intracapsularly. The operation method is the same as before. According to the nature of the tumor and the severity of adhesion to the surrounding tissue, total tumor resection, subtotal resection or partial resection is performed. After the tumor is resected, the tumor bed is carefully examined for bleeding and low-power bipolar coagulation to stop bleeding. The cerebellum in the third ventricle was cleaned and washed repeatedly with a large amount of physiological saline. Note the smoothness of the upper mouth of the midbrain aqueduct, and the cerebral ventricle was filled with physiological saline. 6. Guan skull The dura mater is tightly sutured, the bone flap is restored, and the periosteum, cap aponeurosis, and skin are sutured. 7. Ventricular drainage Drill holes in the right forehead and continue drainage through the anterior horn. complication 1. Postoperative hemiplegia: caused by damage to the central vein, recovery is incomplete. 2. Prolonged coma: Intracerebral and cerebral venous injury, blood backflow blocked. 3. Difficulties in language and writing: The brain is superior to the patient's carcass incision, and the language center should be checked before surgery. Tumors in this area with the advantage of cross-brain are switched to surgical procedures without carcass. 4. Hypothalamic injury, hydrocephalus.

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