Pioneering gamma knife treatment increases access for international patients with rare brain malformation
Children from around the world with arteriovenous malformations, a rare brain malformation otherwise known as AVM, can now receive treatment with the well-established Gamma Knife technique in London, U.K. The procedure, which is now available to international patients treated at Great Ormond Street Hospital (GOSH), is set to improve the lives of hundreds of children suffering from AVMs. This technique offers potentially lower risks to the patient compared to other surgical options currently available and offers a long-term solution for deep and small AVMs that are impossible to operate on using traditional approaches.
AVMs occur in the brain and consist of a tangle of blood vessels within the brain tissue, which results in the diversion of blood through abnormal blood vessels causing it to bypass the surrounding normal tissue. AVMs occur in about less than 1% of the population, and they are usually developed at birth. These tangles lead to a weakening and eventual dilation of the blood vessels. Some AVMs do not cause any complications and are only found during a brain scan for another reason. However, depending on where they occur, AVMs can cause abnormal bleeding in 50% of cases, and seizures in 25% of cases. In some cases, the complications can be life-threatening.
Consultant paediatric neurosurgeon, Dr Greg James, from GOSH explains that patients who suffer from AVMs have several treatment options: they can be operated on and removed; they can be blocked up through a process called embolization or treated with the gamma knife technique. In some cases, patients can be treated by all three methods. According to Dr James, the Gamma Knife technique is not always the treatment of choice because, unlike the other two treatment options, it can take up to five years to work. “It tends to work gradually, not overnight and can’t be used for very big AVMs due to the technique’s precise nature. It is also often used for very deep AVMs that would be too risky for open surgery or embolisation,” explains Dr. James.
Gamma knife is a very precise and well-established form of radiotherapy. During the procedure, the doctors can determine which areas will get radiation and which areas will not in order to limit the brain’s exposure to radiation. Dr. James says, “Gamma Knife works like a colander. It uses very weak beams which then all intersect and generate a high dose of radiation. Meanwhile, the surrounding brain area is protected and limited to a very low dose of radiation”.
“Published evidence indicates that there is an 80-85% complete cure of AVMs with Gamma Knife,” says Dr. James. He also stresses that the procedure is extremely safe and the child should be able to go home the next day. “Generally we do the treatment on a Friday and the kids are back at school on a Monday. So they tolerate it very well,” he says.
To date, GOSH, who treat 1,500 children from the Middle East every year, has performed nine Gamma Knife procedures. One of these includes Kuwaiti girl who only recently had her AVM diagnosed after she experienced a bleed on the brain.
Dr. James stresses the importance of involving the family in the whole experience. “As a team of doctors it is important to us to meet the family together to explain why we believe Gamma Knife is best for their child, as well as explain the treatment to them and show them pictures so they are fully informed and involved in the decision-making process”.