A Different Kind of Surgery

For a patient diagnosed with several kinds of brain tumors, going “under the knife” has come to mean a completely different type of procedure than previously thought. When I was in nursing school for my undergraduate degree (many years ago) I remember how amazed I was that I had to opportunity to see brain surgery during my surgical rotation. The surgeon was quite accommodating and allowed these green nurses to come right into the thick of things for an incredibly memorable experience. The patient’s head was shaved clean, bore holes were strategically placed and drilled and then a saw-like instrument was used to cut between the bore holes. Finally a piece of the patient’s skull was removed to expose the brain and the tumor that would eventually be debulked or removed. I still remember thinking “Wow, I’m standing three feet from someone’s exposed brain!”

The surgery was long and tedious and often without tremendous side effects to the patient. Still today, there are some neurosurgeries that require this approach. But unbelievably, many types of brain tumors today can be treated with a much less disfiguring type of surgery. Stereotactic radiosurgery (SRS), including gamma knife and cyber knife have become the treatment of choice for many types of brain tumors. Cyber knife is also used to treat spine, lung, liver, prostate, pancreas and kidney cancers according to Accuray.

Unlike traditional radiation treatments using a linear accelerator or other equipment, Gamma knife allows noninvasive brain surgery to be performed in one session and with extreme precision, sparing tissues adjacent to the target. This allows for much greater control of accuracy and much fewer side effects associated with traditional radiation therapy.

According to the International Radiosurgery Association (IRSA) stereotactic radiosurgery works the same as all other forms of radiation treatment. It doesn’t remove the tumor, but distorts the DNA of the tumor cells. The cells then lose their ability to reproduce and retain fluids. Sterotactic radiosurgery can be used in a variety of instances. If someone has a rapidly growing metastasis, this technique can be used to control the tumor growth until conventional treatment including chemotherapy can be employed. In addition, if a patient has previously failed whole brain radiation or reached a maximum dose, radiosurgery is often a good choice. A patient can be treated in one sitting or hyperfractionated doses over time.

During the treatment, a frame is screwed into the patient’s head to maintain the exact positioning needed. Often for fractionated doses some type of mask is also employed that allows for greater accuracy over time. With cyber knife, the patient is treated in few to several sessions over time. With all types of radiosurgery, accuracy is the key. Computerized images of the patient’s brain are used to determine the treatment plan and direct the beams of radiation to the exact spot that is needed. The most frequent side effect seen with SRS is edema. Because the cells lose their ability to regulate fluid some edema may occur. This is often able to be treated with medications most commonly steroids.

As with all radiation therapy, the type and degree of side effects is easily correlated to the dose of radiation and the amount of healthy tissue that is exposed to the radiation field. With SRS neurosurgeons and radiation oncologists can target a much smaller radiation field, thus decreasing the degree of side effects noted. Patient’s can receive their treatment often in one or few visits with minimal disruption to their lives. A far cry for sure, from the time when most types of brain tumors required long hospitalizations following disfiguring surgeries. Now, instead of saying “Wow, I’m standing three feet from someone’s brain” I can say “Wow, we can get to one tiny spot inside of a person’s brain with no tell tale signs of entry into the brain at all!” Fortunately it’s true that we just keep getting better.