NeuroLogic - When Tumors Attack the Spine
When Tumors Attack the Spine
Date: June 1, 2009
Fifteen years ago, only about one out of 10 spinal tumor patients was a candidate for surgery, says Ziya Gokaslan. Today, he estimates, that figure is eight or nine times greater. The reason: innovations in surgery.
“We didn’t have the approaches needed to access the tumor,” says Gokaslan, director of the Johns Hopkins Spine Center. Moreover, surgeons were severely limited in their ability to reconstruct the spine.
Gokaslan and his colleagues treat both patients with extrinsic tumors, which arise from the bone or soft tissue of the spinal column; and those with the less common intrinsic, or intramedullary, tumors, those that originate from the spinal cord itself.
The surgical team begins by first removing any segment of the spine bone that blocks access to the tumor. They then use microsurgical techniques to remove the tumor. In some cases, the team uses a laser and ultrasonic aspirator to vaporize part or all of the tumor.
Throughout the procedure, the patient’s spinal cord function is constantly monitored through electromyography, motor evoked potentials or somatosensory evoked potentials. “If we see changes in these recordings, then we make a decision as to whether it’s safe to proceed,” says Gokaslan.
If a portion of spine has been removed, reconstruction is the next step. Spinal tumors can range from a few centimeters in length to the size of a watermelon, and in the latter case, the reconstruction can be highly complex. “Fifteen years ago,” notes Gokaslan, “outside of a few screws and a rod, we didn’t have anything to reconstruct the spine.” Today, they’re rebuilding spines with titanium cages, plates, spacers and other implants.
Among the particularly challenging forms of spinal tumor are those that grow on the spinal cord. Neurosurgeon George Jallo specializes in such cases. Many of his patients have been told by previous doctors that their case is inoperable. Last year, for example, he cared for a 17-year-old who had the extremely rare spinal tumor known as an ependymoma. Doctors at the boy’s local hospital had concluded that surgery to remove the tumor would be too risky. They administered radiation therapy instead. Still the tumor continued to grow. “He then had surgery here,” says Jallo, “and we were able to remove the entire tumor without any new deficits, and he is doing well.”
A surgeon’s reluctance to operate in this vulnerable region is understandable, says Jallo. “The margin of error is on the order of millimeters.” But with a practiced team of specialists, those risks are significantly reduced. The Johns Hopkins Spine Center is one of a handful of places that specializes in spine tumor surgery, says Jallo.
Still, even with a dedicated team of specialists, any surgery on the spine involves a degree of risk. So both Gokaslan and Jallo in their research labs are searching for less invasive alternatives. Instead of a complete surgery, for example, one option is to make a small incision and apply a chemotherapeutic agent near the tumor site, an approach they are testing in animal models. “We haven’t found a cure yet,” says Jallo, “but we have promising results.”
To refer a patient: 410-955-6406