No Margin

The goal of tumor surgery anywhere in the body is to "get the cancer out." When a surgeon excises a tumor from an organ like the breast, lung, kidney, or skin, the risk of recurrence is reduced by intentionally taking out "a margin of good tissue." With brain tumors, this is not an option. Removing a margin of good brain tissue could result in severe neurological deficits with unacceptable reductions in quality of life. Volumetric stereotactic technology is the best available tool for enabling a surgeon to "see" the all-important but elusive boundary between a tumor and a patient's brain.

Seeing the Unseeable

Radiographic and magnetic images are converted into a detailed 3-dimensional model of an individual patient's brain, by using a unique computer application called COMPASS, developed by Dr. Kelly and his colleagues.

COMPASS integrates enormous streams of data to create clear 3-D images of the tumor — positioned precisely within the surgical target area — and the associated vasculature, anatomical landmarks, and functional markers. A robotics-controlled stereotactic headframe, attached to the patient's skull with four pins, is used to ensure precision during the acquisition of the images, and during surgery.

Enhancing the Surgeon's Eye

During surgery," Dr. Kelly continues, "normal brain tissue and tumor often look alike to the eye, but having the volumetric stereotactic image before me extends my vision, letting me 'see' the entire tumor inside and out. Most important, it lets me know exactly where the tumor ends and the brain itself begins, allows me to remove the whole tumor and nothing but the tumor."

Virtual Reality

Throughout surgery, a "virtual reality" image of the brain is projected in front of the surgeon's eyes by a "heads-up" video display unit mounted on the operating microscope.

"What I see through the microscope," says Dr. Kelly, "is not only the actual surgical field itself, but also the computer-generated rendition of what actually is there and what's below the surface. I can see where I am and where I'm going."

"With this technology, you can also see and remove deep-seated tumors which might otherwise be considered inoperable."

Clinical and Econimical Effectiveness

Using the stored 3-D image on a computer screen, the surgical procedure can be simulated beforehand, to identify the optimal approach. Before going into the operating room, the surgeon can decide where to open the skull, how large to make the craniotomy, and what essential tissue and blood vessels to avoid. Because the hole in the skull, the path to the tumor, and the excision are substantially smaller than in conventional neurosurgery, injury to the brain is further minimized.

Dr. Kelly and his colleagues have conducted a study of 1,165 patients at NYU Medical Center and Mayo Clinic who had computer-assisted stereotactic neurosurgery.

"We found that the tumors were completely removed in more than 90 percent of the cases," Dr. Kelly points out, "and the surgical mortality rate was less than one percent."

"Because of its precision, computer-assisted stereotactic surgery yields not only better clinical outcomes — such as minimizing neurological damage and increasing survival — but also achieves economic savings. The time patients spend in the operating room is reduced, sometimes by two or three hours. In addition, because of fewer postoperative complications and quicker recovery, patients are able to leave the hospital sooner. Also, they are less likely to have to return for additional surgery, because of the high success rate in the total removal of tumors."