Can this kind of "deformity" in the brain be removed surgically?

Author: Wang Shuo, Chief Physician, Beijing Tiantan Hospital, Capital Medical University

Chairman of the Neurosurgery Branch of the Chinese Medical Association

Reviewer: Wang Jiawei, Chief Physician, Beijing Tongren Hospital, Capital Medical University

Cerebrovascular malformation is a disease of abnormal development of cerebral blood vessels, which can be divided into four categories. The most common one is arteriovenous malformation, whose pathological feature is a direct connection between intracranial arteries and veins. It can cause a series of clinical symptoms such as cerebral hemorrhage, epilepsy, headache, language disorders, limb numbness, and visual field defects.

We mainly talk about the treatment of arteriovenous malformations.

1. What are the treatments for cerebrovascular malformations?

The main treatments for cerebral vascular malformations include: surgical treatment, embolization therapy (intravascular interventional therapy), stereotactic radiotherapy, combined treatment and conservative treatment.

Surgery is the most traditional and oldest treatment for cerebral vascular malformations. It has been around since the mid-19th century, but the effectiveness of surgery has only improved significantly since the use of microscopes. Currently, surgery is still the main treatment. The treatment is to directly remove the abnormal vascular malformation through craniotomy to achieve the desired effect.

Embolization therapy is an intravascular treatment that uses a catheter to "block" the site of cerebral vascular malformation with embolic materials, so that the arteries and veins no longer communicate with each other.

Stereotactic radiotherapy, also known as gamma knife therapy, uses radiation to irradiate the lesion, causing the endothelial cells of the vascular malformation to degenerate, proliferate, and eventually close and die. However, gamma knife therapy takes a long time. Generally speaking, it takes about two or three years of observation after treatment before the vascular malformation can be closed.

The use of combined treatment is often based on the characteristics of arteriovenous malformations, using two or three of the above-mentioned treatment methods in combination to increase the cure rate while also reducing the risk of treatment. It is often used for complex arteriovenous malformations that require treatment.

A foreign journal has a meta-analysis that summarizes many cases. The statistics show that among the three treatments for cerebral vascular malformations, surgical treatment has the best effect, achieving 96% complete resection, that is, cure. The cure rate of embolization treatment is relatively low, about 10%-20%, and is mainly used as an auxiliary method. Gamma knife treatment can achieve a cure rate of about 38%, but the appropriate indication must be selected.

Therefore, surgical treatment is generally recommended for cerebrovascular malformations of a better grade.

2. Which cerebral vascular malformations can be removed surgically?

The first is cerebral vascular malformation with bleeding. Because cerebral hemorrhage may be life-threatening, and once bleeding occurs, it often occurs a second or even a third time. It will take about ten years for the bleeding rate to drop to about 2%-4% per year. Therefore, active intervention is necessary for these patients.

In addition, active intervention is also recommended for smaller cerebrovascular malformations with a history of bleeding, infratentorial vascular malformations, and cerebrovascular malformations confirmed by angiography to contain aneurysms, because the probability of bleeding is relatively high.

Generally, for unruptured vascular malformations, intervention is recommended for grades I and II. However, for higher-grade grade III or grades IV and V containing functional areas, active intervention is not recommended because the damage caused by intervention is too great.

3. What preparations need to be made before cerebrovascular malformation surgery?

Like all surgical operations, cerebrovascular malformation surgery requires a check of the patient's basic physical condition to see if he or she can tolerate the surgery, such as the condition of the heart, lung, and kidney function. The anesthesiology department also needs to do a basic assessment to see if the patient can be anesthetized.

MRI, CT, angiography and other examinations are also needed to evaluate the condition of the lesion and the benefits of surgery. If the lesion is very close to the functional area, such as the hand functional area or language functional area, functional MRI can also be performed to evaluate whether the functional area can be avoided during surgery to avoid damage as much as possible.

Therefore, there are two main assessments before cerebrovascular malformation surgery. One is the assessment of routine physical condition, and the other is the assessment of lesion conditions and surgical risks.

Figure 1 Original copyright image, no permission to reprint

4. Is cerebrovascular malformation surgery performed under local or general anesthesia?

99% of brain surgeries are performed under general anesthesia, and local anesthesia is rarely chosen. Therefore, cerebral vascular malformation surgeries are basically also performed under general anesthesia.

There is a type of surgery called intraoperative awakening surgery, which also belongs to general anesthesia. However, during the operation, the patient is awakened to determine the need for a certain function, such as asking him to move his hands, or talk, or cooperate in some movements, but the whole process is still under general anesthesia.

5. What are the risks of cerebrovascular malformation surgery?

Any surgery will have risks. The first is the risk of death. Although the probability of accidents during surgery is very low and anesthesia is relatively safe, there is still a certain mortality rate. Currently, the mortality rate of cerebrovascular malformation surgery worldwide is about 0.4%.

Another is the risk of postoperative disability, which is also the most concerned issue for patients and doctors. For example, functional loss, including language, limb movement, coordination, vision, visual field damage, etc., the degree of damage is related to the location of the lesion. If the lesion is in the relative sub-area, there will generally be no damage, but if the lesion is in the functional area, such as the language function area, motor function area, etc., there may be functional loss after surgery.

6. How should patients with cerebrovascular malformations be followed up after surgery?

Depending on the treatment method, the requirements for patient follow-up are also different.

After surgery, patients with cerebrovascular malformations are routinely reviewed with angiography to check whether the malformation has been completely removed. Literature reports that 96% of cerebrovascular malformations can be removed cleanly. If the initial review is successful, a review every 1-2 years is sufficient.

The reexamination mainly depends on several aspects. The first is the medication situation. Patients may take some medications after surgery. For example, patients with epilepsy and patients without epilepsy may also take preventive medications, that is, to prevent epilepsy during the perioperative period. Therefore, doctors should understand the medication situation of these patients during the reexamination. Because epilepsy drugs may damage liver and kidney function, patients are also advised to check their liver and kidney function regularly.

In addition, CT or CT angiography is needed to check the patient's brain function recovery, such as whether there is hydrocephalus, etc. CT angiography can also be used to preliminarily check whether there are any residual vascular malformations. Generally, cerebral angiography should be reviewed again 6-12 months after surgery, especially for patients who have received embolization treatment, to understand the treatment situation. For other patients, if there are no special circumstances, it is generally sufficient to review once every one or two years.

For patients who undergo gamma knife radiotherapy, angiography is generally required about one year or one and a half years after surgery to check the degree of vascular occlusion. A cerebral angiography must be repeated about three years after surgery to see if the blood vessels are occluded. If they are completely occluded, they are considered cured. Note that for these patients, even if they are cured, it is still recommended to recheck about five years after surgery, as some patients may experience recanalization.