Gamma Knife Brain Surgery: No Pain, No Incision, No Anesthesia

For people diagnosed with brain tumors, the outlook can seem bleak. But thanks to a revolutionary technology that’s been available at Froedtert & Medical College since the end of 1999, treatment for many patients has become much more promising, faster and relatively painless.

The technology is the Gamma Knife, which – despite its name – is not a knife at all but a helmet-like device through which patients receive highly focused beams of radiation that destroy tumors but spare healthy tissue.

Gamma Knife offers amazing advantages to patients; but what it does not provide can be even more impressive and comforting. Gamma Knife surgery entails:

• No head shaving, incisions or sutures.
• No scarring and virtually no pain.
• No general anesthesia – patients go home the same day or the day after.
• No convalescence, rehabilitation or extended absence from work or family obligations. Many patients can resume everyday activities within days of the procedure.

“And it’s just as effective as conventional brain surgery or even newer microsurgical techniques,” says Thomas A. Gennarelli, MD, Chairman of the Department of Neurosurgery and Professor of Neurosurgery at the Medical College of Wisconsin. “With Gamma Knife, we can now treat many people as outpatients. That includes those who would not be good candidates for conventional surgery, such as people with major medical problems or elderly patients.”

Reduced Risk, Lower Cost
Among its many benefits, Gamma Knife surgery means significant cost savings over traditional surgery because of the shortened hospital stay, Dr. Gennarelli noted. “And the risks of surgical complications – such as infections, hemorrhage and adverse reactions to general anesthesia – are eliminated. It’s much easier on the patient.”

Since Froedtert & Medical College acquired Gamma Knife technology, it’s been used to treat more than 200 patients from Wisconsin and northern Illinois.

A Gamma Knife procedure takes about three hours and requires a team of specialists including a neurosurgeon, a radiation oncologist and a medical physicist, Dr. Gennarelli says. While the patient is lightly sedated, the team develops a treatment plan by creating an image map of the patient’s brain using computers and diagnostic imaging.

Next, a large helmet with 201 portals is positioned on the patient’s head. Through the portals, a highly accurate pinpoint of cobalt-60 gamma ray beams is delivered to the tumor. The precise radiation destroys the tumor with little or no damage to surrounding healthy tissue. That is important, because a major challenge in removing a brain tumor is avoiding critical structures that affect a patient’s motion, memory and similar critical functions. Because of its precision, Gamma Knife is also used in children’s surgery, Dr. Gennarelli says.

Role of Computers and Diagnostic Imaging
Gamma Knife technology was actually developed in Sweden about 50 years ago. It wasn’t widely used for treatment until recently, with rapid advances in diagnostic imaging and computer technology.

Not every type of malignant and benign brain tumor can be treated with a Gamma Knife procedure. For example, lesions larger than 4 cm (about the size of a small tomato) cannot be treated. Its use in treating primary malignant brain tumors may be restricted because of the difficulty in identifying the tumor margins. Gamma Knife can, however, also be used as a radiation boost in patients who have already undergone conventional radiation therapy.

Gamma Knife is also used successfully in treating an excruciatingly painful condition involving the face called trigeminal neuralgia (formerly called tic douloureux). It’s also used to treat vascular lesions such as arteriovenous malformations (AVMs), tumors in the base of the skull and other neurological disorders.

Gamma Knife has been widely used for benign tumors such as acoustic neuromas, in which the patient’s auditory and facial nerves can be adversely affected either by the tumor or by the surgery to remove it. With Gamma Knife treatment, Dr. Gennarelli says, many acoustic neuroma patients have a considerably better outcome than with conventional surgery: their hearing is preserved in 80% of cases, the likelihood of facial paralysis is reduced to near 0, and the risk of death during the procedure is virtually eliminated.

Medical College of Wisconsin physicians are conducting a number of clinical trials involving Gamma Knife, Dr. Gennarelli says. One involves comparing the results of Gamma Knife procedures and conventional radiation for certain conditions. Another is exploring ways to use it more effectively in treating malignant tumors.

Although Gamma Knife is a revolutionary technology, it is far from the only advance in the treatment of brain and other neurological disorders, says Dr. Gennarelli. “There are new treatments for epilepsy and Parkinson’s disease that weren’t available until recently.” Those breakthroughs, along with Gamma Knife technology, offer a much brighter future for patients with extremely challenging diagnoses.

Barbara Abel
HealthLink Contributing Writer

MCW Health News presents up-to-date information on patient care and medical research by the physicians of the Medical College of Wisconsin.