Subchoroid plexus approach for third ventricle and pineal region tumor surgery

Large tumors in the middle of the third ventricle enter the third ventricle only from the interventricular septum and the one side of the sacral column. The scope of the field is limited, and there is concern about the possibility of affecting memory. Asenjo (1963) proposed that the posterior margin of the foramen and lateral ventricle incision was enlarged and the third ventricle tumor was removed. Hirsch (1979) and Delandcheer (1979) reported that the frontal lobe enters the lateral ventricle, cuts the posterior margin of the interventricular septum and cuts the posterior margin of the interventricular septum, lifting the choroid plexus, the iliac crest and the internal cerebral vein to enter the thalamus. The tumor was removed from the top of the third ventricle. His 8 patients had good postoperative results without disability and death. Viale et al. (1980) reviewed the literature and concluded that cutting the venous vein may lead to hemorrhagic infarction in the basal ganglia. Therefore, it is proposed that the venous plexus should not be removed from the lateral ventricle, together with the corpus callosum and the third ventricle. The choroidal tissue is pushed to the contralateral side, and the esophageal membrane is cut inwardly into the third ventricle, and the tumor is removed. The anterior portion of the tumor can also be removed through the interventricular hole alone. Lavyne et al (1983) also cut the mound vein according to the Hirsch method, and under the choroidal tissue (middle sail), the fissure between the inner surface of the thalamus and the top of the third ventricle entered the ventricle and resected the tumor. A total of 8 cases were performed. Disability and death. Domestic research found that 2 cases underwent Hirsch method, 1 case went smoothly, and another case had intraoperative brain swelling and postoperative death. Therefore, it is difficult to determine whether the mound vein should be cut off. Zhou Dingbiao (1991) reported 8 cases of third ventricle tumors treated by choroidal fissure in the lateral ventricle. It is believed that the operation of the anterior middle cerebral tumor can not remove the sacral vein, that is, the tumor is removed through the choroidal fissure and the interventricular space. Good results. Treatment of diseases: pediatric brain tumors Indication 1. Large tumor in the middle of the third ventricle. 2, the third ventricle tumor was cut through the interventricular septum and the first half of the tumor was removed, and the latter half remained. 3. The pineal body area and the posterior part of the third ventricle only removed the second half of the tumor through the posterior approach, leaving the first half. Contraindications 1. Tumors in the pineal region, especially to the posterior cranial fossa, this approach is far away. 2, the third ventricle posterior germ cell tumor sensitive to radiotherapy should not be the first choice for resection. 3. The tumor in the anterior third ventricle is still better with the interventricular septum and the one side of the humeral column. 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 before the craniotomy, the ventricle drainage of the forehead or occipital angle on the opposite side of the operation, and removal within 5 to 7 days after the operation. Surgical procedure 1, scalp incision The right frontal flap was incision, the leading edge was located in the hairline, the medial side was near the sagittal midline, and the posterior side was near the central anterior gyrus. The flap was dissected under the cap aponeurosis and turned to the outside. 2, bone flap craniotomy Drill 4 to 5 skulls, the inner hole is next to the sagittal sinus, and the outer hole is 6 to 7 cm from the midline. The bone flap is connected to the periosteum and turned to the temporal side. 3, dural incision The dura mater is connected to the sagittal sinus and is sutured to the sinus side after incision. 4, brain and ventricle incision In the right frontal center, 2 cm from the center and 2.5 cm from the center line, a 4 cm front and rear longitudinal incision was made forward. Before the incision, the cortical blood vessels were cut by bipolar electrocoagulation, and then the frontal lobe was cut into the anterior horn of the lateral ventricle to see the main structures such as interventricular pores, choroid plexus, mound vein, caudate nucleus, sputum and transparent septum. The snake-shaped fixed retractor is used instead of the common brain plate to open the brain incision, and the subsequent operation is preferably performed under a surgical microscope. 5, reveal the tumor Large tumors can be seen in the enlarged interventricular pores or their anterior poles. According to the method proposed by Hirsch, the bifurcation vein was cut by bipolar electrocoagulation at the interventricular space, and the lateral ventricle choroid plexus was lifted. At the fissure between the corpus callosum and the inner edge of the thalamus, the ependymal membrane is cut by a micro-stripper and communicated with the posterior edge of the interventricular septum to enter the third ventricle, which can more fully reveal the tumor. If the method of Viale does not cut the veins of the nucleus, that is, under the choroid plexus of the lateral ventricle, along the choroidal fissure between the thalamus and the corpus callosum, the ependymal membrane is cut into the third ventricle, and the tumor can be found. However, the scope of this law is limited. 6, tumor resection After the tumor is fully exposed, the soft and hard texture, the number of surface vessels and the relationship with the surrounding structure are examined, and then the tumor is removed. The method of excision has been as described above. If the Viale method is not used to cut off the posterior margin of the sacral vein and the interventricular septum, the anterior segment of the tumor may be removed due to limited surgical field. If you still have difficulty, you can also consider changing the Hirsch method for tumor resection. 7, the skull Before the skull is closed, the continuous drainage tube of the ventricle can be drawn through the posterior lateral bone hole of the bone flap, and then the dura mater is tightly sutured, the bone flap is reset, and the suture is layer by layer. complication 1, postoperative epilepsy, accounting for 5% to 10%, the application of anti-epileptic drugs in the perioperative period. 2, the side of the sacral column does not cause memory loss, the damage of the sacral column on both sides can cause persistent memory loss, should be prevented as much as possible. 3, hemiplegia, seen in the posterior motion of the brain incision cortical injury. 4, excessive traction in the ventricle may damage the thalamus, caudate nucleus, and iliac crest, should pay attention to the placement of the brain pressure plate, and use cotton pads to protect the nerve tissue. 5, the third ventricular wall damage can cause hypothalamic injury syndrome. 6, hydrocephalus. Due to intraoperative and postoperative hemorrhage, obstructive or traffic hydrocephalus occurs, and the ventricle continues to drain after operation. When the extubation is difficult, shunt surgery should be performed. 7, hemorrhagic infarction in the basal ganglia may be due to the cutting of the venous vein.

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