Innovations In Neurosurgery
September 22, 2010
By Dr. Maurice Nicholson
Dr. Maurice Nicholson
Neurosurgeon at Gamma Knife Center of the Pacific
Where did you receive your training/schooling?
I graduated from the University of Alberta in Canada. I did my postgraduate work in the United States. I did one year at Queen’s Medical Center and four years in Michigan at Henry Ford Hospital, which is a big teaching hospital. And then I came here. In 1998 I went to Stockholm to take a course on Gamma Knife, which is where the technology originated.
How long have you been practicing?
I’ve been practicing as a neurosurgeon for 44 years as of this past July. December of ‘98 is when we did our first Gamma Knife.
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What is a Gamma Knife and what do you do at the Gamma Knife Center?
The Gamma Knife is a machine that treats brain lesions. It not only treats malignant cancer-type lesions, but also benign conditions. For instance, benign tumors like acoustic neuromas, which grow on the eighth nerve, previously had to be operated on. They now can be treated with Gamma Knife so that you don’t have to have open surgery. A condition called trigeminal neuralgia is a severe face pain disorder, and previously there were a variety of medical treatments that sometimes worked on our patients. If they fail, then they go on to have Gamma Knife, which is about 80 percent successful in stopping that pain problem and it doesn’t require open surgery, which is what used to be done. There’s another condition called arteriovenus malformations. This is an abnormality that we see in children. It’s a tangle of arteries and veins, and sometimes they’re deep within the brain. The problem is that they hemorrhage and they can cause paralysis or death. In the old days, you’d try to operate on them, but sometimes the results were not very good and you could end up with a lot of neurological damage. Now we can treat a lot of those with Gamma Knife and it saves a lot of very traumatic surgery.
A big new area is malignant tumors for people who survive their initial cancer, like women with breast cancer. People live a lot longer now, and one of the side effects is that they develop metastases (where cancerous tumors spread to the brain area). Ten years ago and back, if you came in and you had two or three metastases in the brain, you would get whole brain radiation. But whole brain radiation can have some bad effects. Short-term effects are you lose your hair, and you get radiation sickness sometimes. Longer-term effects are that you can get mental deterioration, not everybody, but some. With the new type of Gamma Knife (the Leksell Gamma Knife Perfexion) we have, it’s easy to treat multiple metastases - you just zap each particular little tumor - and by doing that the whole brain doesn’t get a lot of radiation, and therefore you do not lose your hair, you don’t get the radiation sickness and you don’t get the mental deterioration.
You only treat the brain, right?
The head and upper cervical spine. So, we see a lot of women with breast metastases and lot of people with lung cancer, but we don’t treat the lung or the rest of the body. We treat the metastases.
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Does Gamma Knife just zap the tumor or actually remove it?
Yes, it “zaps” it, for want of a better word. The radiation beams destroy the DNA composition and it stops growth. A lot of tumors will shrink down and sometimes they completely disappear.
Can you talk about the new Gamma Knife Perfexion that you’ll be using for the first time today?
These machines weigh 20 tons. They have radioactive cobalt inside so they have to be in a protected room. The advantage over the old machine is that it’s more automated, so it’s faster when you treat. It’s safer, with less radiation dose generally in the room, to the point where you can almost have a window instead of a lead door to look in. And the treatment planning is easier because of advances in the computer programs. For the patient, it’s very advantageous: quicker treatment times, a little better accuracy and much less radiation that can affect any other part of the body. They really just don’t get radiation other than what’s in the brain with this new machine, which is something that you can’t say for a lot of the other systems that are used.
What does the treatment process look like?
When someone comes in to be treated, they come into the pretreatment room. We start an IV, give them a little sedation sometimes, put the head frame on and then they go to get an MRI or a CT scan. The images are imported into the computer and the doctors work out the treatment plan. Then we bring the patient in, put him on the table, put a bolster under his knees, make sure he’s comfortable. You can fit up to 600 pounds on the table.
The treatment is completely silent, so we play the right music, then we all leave the room and we close the door. We talk to the patient, we can talk back and forth - there are speakers - and we tell them, “OK, the table’s going to slide now, your treatment is going to start.” The table slides into where the radiation is, and you just lie there and you don’t feel anything. Treatment varies with the complexity of what we’re treating. Some treatments are as short as 20 minutes. Some - if you have a lot of metastases - can take three hours. We can see the patient because there are three cameras. When they’re all finished, the patient is put in the sitting position and we take the frame off.
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With the old machine, we sometimes had to do seven shots. You go in and treat for a certain amount of time, and then that shot is over and the table would come out, and you go in and make manual adjustments. Then you go out, shot No. 2, patient goes back in. With the Perfexion, you just go in and everything adjusts on its own, so there’s no coming in and out between shots, so that saves a lot of time.
We can conform to some very irregular tumors. Some of those complicated tumors used to take 10 to 12 hours to get them out. A couple hours on a machine like this is a lot easier on the patient and the doctor. The beauty of it is it’s outpatient, so you can come in this morning and have your brain tumor or tumors treated, and you go home after lunch.
How many patients does the Gamma Knife Center have per year?
One hundred and forty, and we anticipate it’s going to increase with the new machine because we can treat more things. Every patient who is treated here is presented at a conference, and that conference consists of three to five neurosurgeons; three to five radiation oncologists; a neuroradiologist - usually two of them and sometimes a few neurologists. Nobody treats without passing the committee.