intracranial arteriovenous malformation embolization

Cerebral arteriovenous malformation is a congenital regional cerebral vascular dysplasia. There is an abnormal sinus between the artery and the vein, and the blood flows directly from the artery into the vein to form a short circuit. Since there is no capillary network between the normal small arteries and veins, the blood flow resistance is reduced, the flow rate is increased, and the supply artery is gradually expanded to accommodate the increased blood flow. The distal vein stagnates and varicose forms a collateral circulation, and gradually expands and joins the lesion area to form a vascular group of varicose veins and vein intricate clusters with different diameters. Subarachnoid, intracerebral or intraventricular hemorrhage can occur, even in the brain hematoma, occasionally subdural hematoma. Bleeding can cause damage to brain tissue, resulting in symptoms and sequelae of corresponding neurological deficits, and even severely life-threatening. About 30% of patients develop epilepsy. The main basis for the diagnosis of this disease is cerebral angiography, which should be carried out as soon as possible after the bleeding is stable. It is best to perform selective whole brain angiography through the femoral artery puncture cannula, and apply digital subtraction and magnification techniques to better display the extent of the lesion, supply arteries, drain veins, and steal blood. Superselective cerebral angiography via microcatheter is also performed to analyze the vascular structure of the lesion. The blood supply of the abnormal vascular mass is determined by terminal blood supply or perforation, and there is a direct arteriovenous fistula with arteries. Tumor or venous tumor, as well as the time of arteriovenous circulation, etc., provide the basis for selecting indications, embolization materials and injection methods for embolization treatment. For the lesions located in the important functional area, a regional functional occlusion test was performed by superselecting the microcatheter in place by injecting 5 ml of physiological saline containing 50 mg of amitox sodium from the microcatheter to observe whether the patient had transient neurological dysfunction. Such as hemiplegia, limb weakness, numbness, aphasia and so on. Treatment with surgical resection of the lesion is an ideal method of radical cure, but the lesions are extensively deep or located in important functional areas are difficult to remove. In recent years, the development of microcatheter endovascular treatment technology has opened up new avenues for the treatment of this disease. Treatment of diseases: cerebral arteriovenous malformations Indication 1. The lesion is extensive and deep, and it is not suitable for direct surgery. 2. The lesion is located in important functional areas of the brain, such as the sports area, speech area and brain stem. Serious complications and sequelae will occur after surgery. 3. High blood flow lesions, severe blood stasis, surgical resection of bleeding or excessive perfusion syndrome may occur after surgery, may be partial malformation of blood vessels or blood supply artery embolization, and then surgical resection. Contraindications 1. The lesion is low blood flow, the blood supply artery is too thin, the microcatheter can not be inserted, or the microcatheter can not reach the deformed lesion, and can not avoid the perforating artery supplying normal brain tissue. 2. Superselective cerebral angiography showed that the lesion was a perforating donor, and the regional functional occlusion test produced the corresponding neurological deficit. 3. Severe arteriosclerosis, arterial distortion, and the guide tube cannot be inserted into the internal carotid artery or vertebral artery. Preoperative preparation 1. Patient Preparation 1 Learn more about the medical history, perform a comprehensive physical examination and a systematic neurological examination. 2 Those with a history of epilepsy were treated with antiepileptic drugs before surgery. 3 preoperatively according to the condition of the CT scan plus enhanced scan, MRI, MRA examination. 4 blood, urine routine, bleeding, clotting time, liver and kidney function, chest fluoroscopy, heart, EEG, etc. before surgery. 5 fasting before surgery, iodine allergy test, puncture site (such as the perineum) preparation skin, indwelling catheter. 6 Use a cloth strap to restrain the limbs. 2. Special equipment and instruments Prepare one 116G or 18G puncture needle. 2 diameter 0.89mm, length 40cm guide wire 1 piece. One 36F catheter sheath. One 45F cerebral angiography catheter. One 56F guide tube. 6 with a three-way soft connection tube. 7Y type with valve connector. 8 sets of pressurized infusion bags. 1 to 2 of 9 Magic 3F/1.8F, 3F/1.5F, 3F/1.2F or Magic 3F/1.8F, 3F/1.5F, 3F/1.2FMP catheters. 10 two-way switches, 5 pairs of 1ml syringes. Embolization material NBCA, iodophenyl ester, 3-0 or 5-0 silk segment. 1 eye bend, 1 straight scissors. Surgical procedure Generally, the transfemoral puncture cannula is used. 1. The perineum and bilateral groin are routinely disinfected and sterile towels are placed. 2. Using 1% or 2% lidocaine in the right (or left) side of the inguinal ligament 2 to 3 cm, the femoral artery pulsation is clearly layer by layer infiltration anesthesia, and the patient is neurologically anesthetized. 3. Puncture the right (or left) femoral artery with a 16G or 18G puncture needle, insert the 6F catheter sheath sequentially by Seldinger method, and connect the three-way connecting tube of the catheter sheath to the arterial pressure infusion tube to drain the air bubbles in the tube. Adjust the speed of the pressurized infusion bag slowly and drip, and fix the catheter sheath with a sterile tape. 4. The end of the 6F flat guide tube is molded into a hook shape on the boiling water pot at a angle of 110°, and the end of the guide tube is equipped with a two-way switch, which is filled with a contrast agent. The 6F catheter was inserted into the 6F catheter and inserted into the left and right internal and external cerebral arteries, and the left and right vertebral arteries were subjected to selective whole cerebral angiography under the supervision of TV. The contrast injection rate and dosage: internal carotid artery 6ml / s, a total of 8ml; external carotid artery 4ml / s, a total of 6ml; vertebral artery 5ml / s, a total of 7ml). Understand the location, extent, blood supply artery, malformed vascular mass, drainage vein, stealing blood and arteriovenous circulation time. After the diagnosis is made, the guiding tube is inserted into the lesion side neck or the vertebral artery, and the end of the guiding tube reaches the second cervical vertebra plane. 5. Before the insertion of the microcatheter, the patient is given systemic heparinization, intravenous injection at 1 mg/kg. The first dose for adults is 50 mg. If the treatment is continued after 2 hours, it is added at 0.5 mg/kg body weight, and the adult is given 25 mg vein. Injection, and so on. 6. Remove the 6F guide tube end two-way switch, and connect with a Y-shaped valve joint. The Y-shaped valve joint side arm is connected with the three-way connecting tube, and then connected to the arterial pressure infusion bag infusion tube. After the air bubbles in the net pipe, the speed of the pressurized infusion bag is adjusted to slowly drop. Then insert the Magic or Magic-MP microcatheter into the guide tube through the Y-shaped valve joint valve arm end. After the soft and bendable part of the front of the microcatheter is inserted, tighten the valve and pull out the stainless steel guide wire in the microcatheter. The choice of microcatheter type depends on the lesion location, size, thickness of the blood supply artery and the curvature of the blood supply artery. The general lesion is close to the main blood vessel, the large lesion, and the blood supply artery is thick and straight. Magic 1.8 or 1.5F microcatheter is used; If the intracranial peripheral blood vessels, lesions are small, the blood supply artery is thinner and the curvature is more, the Magic 1.2 or 1.5F microcatheter is used. If the front end of the microcatheter does not have an open-cell balloon, after the blood in the microcatheter overflows and the air is exhausted, a 1 ml syringe can be connected at the end. If the end of the microcatheter has an open-cell balloon, a 1ml syringe can be intermittently pushed into the physiological saline at the end of the microcatheter, the air in the microcatheter is discharged into the guiding tube, and the side arm of the Y-shaped valve connector is opened, and the guide is used. Intraductal arterial blood pressure evacuates air bubbles from the side arm of the Y-shaped valve connector. After the air is to be drained, the three-way connecting tube connected to the arterial pressurized infusion bag infusion tube is connected to the side arm of the Y-shaped valve joint, and under the television monitoring, the micro-catheter continues to be fed along the guiding tube until Send the guide tube. Using the natural impact of blood flow, injecting physiological saline from the guiding tube to increase the impact of blood flow, changing the hemodynamic direction, gently filling the balloon, using the microcatheter end shaping and the external transcatheter guiding method, The catheter is delivered to the diseased blood supply artery, and then the front end of the microcatheter is sent to the AVM lesion. 7. Super-selective cerebral angiography of the lesion by microcatheter (injection of contrast agent with a high-pressure syringe at 1 ml/s, total volume 3 ml), analyze the vascular structure of the lesion, and determine whether the arteriovenous malformation is treated with endovascular embolization. And choose embolization materials and injection methods. 8. If the lesion is a non-essential functional area, a single artery end-type blood supply, NBCA embolization should be preferred. Operation methods and requirements: 1 According to the disease blood flow and arteriovenous circulation time, NBCA is prepared into a mixture of 17% to 25%. 2 Ask the anesthesiologist to observe the patient's condition, control hypotension in patients with high blood flow, and reduce the patient's blood pressure to 2/3 of the baseline blood pressure. 3 Rinse the microcatheter repeatedly with a 5% glucose solution and fill the microcatheter. 4 Please inform the technician to prepare the X-ray machine. 5 When directly injecting, use a 1ml syringe to pump the NBCA mixture, connect the end of the Magic catheter, start the machine, and directly inject the NBCA under the TV monitor. Stop the injection immediately when the blood flow of the lesion becomes slow or the NBCA is drained at the end of the vein. The operator cooperates with the assistant to pull the microcatheter together with the guiding tube from the patient. Or use the "sandwich" injection technique, first draw 5% glucose 0.5ml with a 1ml syringe, then aspirate the NBCA mixture (depending on the size of the lesion), and connect to a microcatheter filled with 5% glucose solution. The end, (with NBCA sandwiched between 5% glucose, not in direct contact with blood outside the body), was injected under TV surveillance and the microcatheter was quickly withdrawn. 6 If the second blood supply artery and lesion embolization are needed, insert a second Magic microcatheter. Generally, only one blood supply artery is embolized in one treatment. 9. If the lesion is located in an important functional area or the lesion is deep and extensive, and is not suitable for embolization with NBCA, silk segmental embolization may be used. Operation methods and requirements: 1 According to the blood flow level of the lesion and the size of the blood supply artery, 3-0 or 5-0 silk medical sutures are made into different specifications such as 0.5-2.5cm, generally high blood flow, and the blood supply artery is thicker. The elders, on the other hand, use the short ones. 2 Aspirate about 0.8 ml of saline for injection with a 1 ml syringe, and send the silk segment into the 1 ml syringe with ophthalmology, connect the syringe to the end of the microcatheter, and push the silk segment through the microcatheter into the lesion with saline. The amount of bolus injection in the silk segment varies depending on the size of the lesion. 3 During the process of injecting the silk thread, 40% non-ionic contrast agent is continuously injected to monitor the lesion embolization. If the blood flow of the lesion is slow or the deformed blood vessel group disappears, the bolus should be stopped, and the intermittent bolus should contain 1 mg per ml. 1 to 2 ml of papaverine to prevent vasospasm. 4 Observe the patient's mind, language function, limb movement, etc. during the process of injecting the silk thread, and stop the treatment immediately if there is any abnormality. If there is no abnormality, the microcatheter can be inserted into another blood supply artery for embolization until the lesion is completely embolized. 10. After the embolization is completed, as soon as possible, understand the patient's condition changes, pay attention to whether there are adverse reactions and complications, and deal with them accordingly. If the patient is in good condition, the cerebral angiography of the same condition as before embolization can be performed through the guiding tube to understand the lesion embolization result and compare with the pre-embolization. 11. At the end of the treatment, firstly inject the protamine intravenously (according to 1ml containing 10mg of protamine, which can be used to neutralize heparin 1000U), and then pull out the guiding tube and catheter sheath. The puncture site is pressed for 15-20 min. When there is no bleeding, the part is covered with sterile gauze and pressed with a sandbag for 5-6 h. complication The main complications of endovascular embolization for cerebral arteriovenous malformation include: mis-suppression of normal cerebral arteries, drainage or venous sinus-induced neurological deficits, hyperperfusion syndrome, intracranial hemorrhage, catheter rupture in the cerebral vessels, and cerebral vasospasm. . 1. The main cause of mis-embolization is 1 microcatheter intubation is not in place, and does not avoid the perforation of normal brain tissue; 2 the blood supply method of cerebral arteriovenous malformation is not terminal blood supply, but blood supply through the branch, can not be avoided when embolization To provide perforation of normal brain tissue, in order to avoid such complications, the microcatheter must be delivered to the site, and embolization can not be performed if the perforator of normal brain tissue cannot be avoided. 3 drainage or venous sinus embolization, more common in high blood flow lesions, short arteriovenous circulation time, improper concentration of NBCA embolization, NBCA quickly into the reflux vein or sinus to embolize, and supply arteries, malformed vascular group has not yet Embolism, intracranial hemorrhage will occur immediately. In order to prevent such complications, in the application of NBCA embolization in high blood flow lesions, the concentration of NBCA must be adjusted according to the arteriovenous circulation time, or the silk segment embolization should be used, or the silk segment, GDC or Liquid coil should be used first. Lesions, when the blood flow from high to low, then NBCA embolization. 2. Hyperperfusion syndrome mainly occurs when embolism of high blood flow lesions, especially when NBCA embolization is used. Because the arteriovenous stenosis is blocked in an instant, the blood that was originally stolen by the lesion quickly returns to the normal cerebral blood vessels, due to the long-term normal cerebral blood vessels. In the state of low blood flow, its autoregulation function is unbalanced and cannot adapt to changes in intracranial hemodynamics. Over-perfusion will occur, resulting in severe brain edema, brain swelling and even uncontrollable intracranial hemorrhage. In order to prevent this from happening, when embolizing a huge lesion of high blood flow, the arteriovenous short circuit should be gradually blocked, and only 1/3 or 1/4 of the lesion volume can be embolized at a time; at the same time, at the time of embolization, even after embolization, as appropriate Controlled hypotension measures reduce the patient's blood pressure to 2/3 of the baseline blood pressure; or gradually block the arteriovenous short circuit with a silk segment embolization, slowly changing the intracranial hemodynamics. More care should be taken for elderly, atherosclerotic and hypertensive patients. 3. The cause of intracranial hemorrhage, in addition to the misplaced drainage vein and venous sinus and hyperperfusion syndrome, is also seen in the following conditions: 1 microcatheter into the lesion, NBCA embolization catheter to stick to the lesion, pulling the tube when pulling the bleeding; 2 When the silk wire segment is embolized, because the catheter stays in the blood vessel for a long time, and the stimulation when pushing the line segment, the cerebral vasospasm is held by the microcatheter, and the diseased blood vessel is broken when the force is pulled. In order to prevent cerebral vasospasm, during the process of injecting the silk thread, the papaverine solution should be intermittently injected from the microcatheter. 4. The reason why the catheter is broken in the cerebral blood vessels is that the microcatheter sticks to the lesion when the NBCA is embolized; 2 when the silk segment is embolized, the catheter cannot be pulled out due to cerebral vasospasm, and the microcatheter is pulled off when pulling; 3 Quality problems with catheter materials.