corpus callosum arteriovenous malformation resection

Although the position of the corpus callosum malformation is deep, it is almost at the brain surface at the bottom of the longitudinal segment of the brain. Of the 34 surgical patients in Yasargil, 30 (88.2%) performed well, with only 1 in the poor. Surgery sometimes involves the corpus callosum and no postoperative split-brain syndrome. The corpus callosum AVM is divided into three types: the anterior part of the corpus callosum AVM, the middle part of the corpus callosum AVM, and the posterior part of the corpus callosum AVM. The venous drainage of the corpus callosum AVM can be divided into three types: 1 drainage to the deep subventricular venous vein, transparent septal vein, intracerebral vein, to the great cerebral vein, is the most common type; 2 in addition to drainage to the large brain vein, still draining To the superior sagittal sinus or the lower sagittal sinus; 3 only to the upper sagittal sinus, the most common. The drainage veins of all corpus callosum AVM should be protected during surgery to prevent intraoperative brain swelling and spontaneous bleeding. The anterior and middle corpus callosum AVM, the blood supply artery is mainly the periorbital artery, the iliac artery, the transparent septal artery and the penetrating artery. The drainage veins flow into the transparent septal vein or the superior and inferior sagittal sinus. The front AVM is mostly triangular. The central AVM is mostly spherical, the base is in the corpus callosum, and can be extended laterally under the buckle back. The tip of the AVM points to the interventricular space. The posterior AVM of the corpus callosum can be extended in the iliac crest or to the lateral lateral ventricle. It is mostly spherical, with the base in the iliac crest and the tip in the lateral ventricle. The blood supply artery is mostly composed of the periorbital artery, and the transparent septal artery and the perforating branch derived from the anterior communicating artery are also seen in the deep part. Sometimes the occipital artery and posterior choroidal artery of the posterior cerebral artery are also involved. The most common drainage veins surround the lateral and medial side of the AVM through the medial atrial vein, which enters the large cerebral vein below the end of the large cerebral vein. When the straight sinus is narrowed or occluded, sometimes the drainage vein can also enter the basal vein. There are few cases of superior or inferior sagittal sinus through the cortical vein. In rare cases, a supply of choroidal blood vessels from the third ventricle can be accepted. Treatment of diseases: subarachnoid hemorrhage Indication 1. There is a history of subarachnoid hemorrhage. 2. Medium and small AVMs with a diameter <4 cm. Contraindications 1. Involvement of a wide range of sides or intrusion into the transparent compartment. 2. Giant AVM with a diameter > 4 cm. Preoperative preparation 1. There must be a correct positioning diagnosis before surgery. In recent years, due to advances in imaging inspection technology, clinical applications such as CT, MRI, and DSA have become increasingly widespread. The relationship between the location of the lesion and the surrounding structure should be analyzed before surgery in order to select the appropriate surgical approach, to obtain the best exposure, avoid the important structure of the skull as much as possible, increase the safety of the operation and strive for good Effect. 2. Skin preparation, wash the head with soap and water 1 day before the operation, shave the hair on the morning of the operation. You can also shave your head on the eve of surgery. 3. Fasting the morning of surgery. It can be enema in the evening before surgery, but when the intracranial pressure is increased, the enema should be removed to avoid sudden deterioration of the condition. 4. Give phenobarbital 0.1g orally before surgery to ensure a quiet rest. One hour before the operation, 0.1 g of phenobarbital, 0.4 mg of atropine or 0.3 mg of scopolamine were intramuscularly injected. Surgical procedure 1. Anterior and middle AVM resection (1) Incision: The right incision was used except that the lesion significantly extended to the left. Forehead flap, the bone flap is about 6cm long and about 4cm wide. The dura mater is a semicircular incision. The base is located on the sagittal sinus side, and the anterior approach of the cerebral longitudinal fissure is taken. (2) Exposing the corpus callosum: The nodule vein is selected at the medial edge of the frontal lobe, and the inner side of the frontal lobe is separated downward. Before the carcass is revealed, the arachnoid adhesion between the cerebral palsy and the cerebral cortex in the longitudinal segment of the brain is separated. For example, the transparent septum is the main drainage vein, which allows 1 to 2 branches to be transferred into the sagittal sinus to break open the field. However, if the main vein is directly drained to the cortical vein of the sagittal sinus, it cannot be severed and must be treated in the final stage of surgery. (3) Blocking the blood supply artery: Once the AVM is exposed, the branch of the periorbital artery that supplies blood to the lesion should be found, and the branches of the blood supply artery should be disconnected, but the trunk of the periorbital artery should not be damaged. The same method can reveal the blood supply branch of the contralateral periorbital artery to the lesion area. Occasionally, on the side of the deformed mass, there may be branches of the orbital artery and the frontal artery. These blood vessels are also cut off after electrocoagulation. The arteries have all been blocked. (4) Free lesions: After the periorbital artery is separated, the AVM can be moved to the medial or lateral side of the corpus callosum, and AVM is further separated from the surrounding brain tissue. There is often a thin layer of gelatinous band around the corpus callosum AVM, which is yellow-orange and free along this layer, which not only facilitates the separation of lesions, but also prevents damage to surrounding normal brain tissue. When separating the AVM, try to leave the drainage vein. If the AVM is in the anterior part of the corpus callosum, the separation should start from the front of the AVM, because the transparent septal drainage vein is behind the lesion. However, for example, AVM resides in the middle of the corpus callosum, and separation should begin with the posterior aspect of the lesion because the transparent septal vein is located in front of the AVM. In addition, separation should also begin on the outside of the upper part of the carcass, as these lesions are often located next to the midline. In the AVM of the iliac crest, some small blood supply arteries from the junction of the corpus callosum at the top of the lateral ventricle and the ependymal membrane were seen. On the anterior junction of the interventricular septum, one or two blood supply arteries can also be seen at the top of the AVM. All blood supply arteries should be disconnected by electrocoagulation. The subependymal vessels are very fragile and should use a weaker current. Sometimes blood supply vessels from choroidal tissue should also be blocked. At this step of surgery, it is especially important to protect the venous veins and the internal cerebral veins from damage. (5) Resection of the lesion: When the AVM is completely disconnected from the blood supply artery and the main vein, the transparent septal vein is electrocoagulated and the malformed vascular group is removed. The transparent septum is just outside the Qianlong column. The Qianlong column forms the front boundary of the interventricular space and is connected to the transparent septum. The dome must be protected from damage during the operation. In a few cases, the main drainage vein is through the superior or inferior sagittal sinus, and these drainage veins should be disconnected at the end. (6) Guan skull: Before closing the incision, to make the systolic blood pressure reach normal, observe at least 15 minutes to see if the hemostasis is true. 2. Posterior AVM resection of the corpus callosum (1) Incision: The scalp incision is opposite to the anterior and middle part. The base of the flap is located at the level of the occipital trochanter and is turned backwards. The flap is 6 cm long, 4 cm wide, and about 2 cm across the midline. The right incision is used unless the lesion is to the left. You can also do a free bone flap or a pedicled flap to the temporal side. The dura mater is turned into a sagittal sinus with a semicircular incision. The surgical operation method is basically the same as that of the front and middle, except that the cranium is craniotomy. (2) Disconnecting the blood supply artery: gently retract the brain outward along the longitudinal slit with an automatic retractor, first revealing the quadrilateral pool, first cutting the arachnoid membrane in the transparent part, and gradually expanding until the corpus callosum and energy See the big veins of the brain. Then, at the right outer corner of the ring pool, that is, at the inner side of the ligament and the isthmus, the annular pool is cut, and the ring pool of the posterior cerebral artery and the superior cerebellar artery is found, and the posterior side of the corpus callosum is recognized. The branch of the periorbital artery in front of the blood supply branches and is electrocoagulated and disconnected. Then, the branch of the blood supply in the posterior part is also cut off, and the branch of the blood supply from the posterior occipital branch of the posterior cerebral artery in the quadrilateral pool. (3) Resection of AVM: After the blood supply artery is cut off one by one, the AVM is removed. The cortex was cut into the paraventricular area of the corpus callosum about 1 cm away from the anterior corpus callosum, and the direction of the right ventricle was released until the AVM was seen. When freeing lesions from normal brain tissue, proceed in the upward and forward direction. Unlike the cerebral large vein AVM, the base of this AVM does not have a thalamic posterior perforator. The pressure portion AVM is introduced into the vein near the beginning of the medial vein of the lateral ventricle triangle. This drainage vein is electrocoagulated (the inner vein wall of this triangle is very fragile, and the coagulation should be careful to use a weak current to solidify), and then the AVM is removed. If the AVM is only located in the iliac crest, it can be cut open and free at its superficial part without starting from the side of the pressure section. complication 1. Because AVM is an abnormal vascular mass, blood supply is extremely rich, such as incomplete resection or electrocoagulation to stop bleeding is not enough, postoperative patient agitation or elevated blood pressure, prone to postoperative hemorrhage to form intracranial hematoma. Once it happens, it should be re-operated immediately to stop the bleeding completely. 2. In patients with large-scale high-flow and chronic progressive cerebral ischemia, normal perfusion pressure breakthrough may occur after AVM resection, resulting in uncontrollable brain swelling and bleeding. Mainly in prevention.