Summer 2006

New Methods Advance Spine Tumor Surgery

UCSF neurosurgeon Chris Ames, M.D., has developed new technologies and techniques for attacking spinal tumors. The techniques offer strikingly different approaches for removing spine tumors and may promise to be more effective at removing the cancer and reducing the morbidity of surgery. Many of the tumors Ames operates on have been deemed inoperable by other surgeons.

One technique that Ames has developed is used for cervical and cervicothoracic tumors that lie anterior to the spinal cord. This lateral transpedicular approach is a new resection paradigm based on the principle of skull surgery, Ames says. During the spine surgery, as during skull surgery, no nervous tissue is retracted to limit mechanical strain on the tissue.

"One common method is to retract the spinal cord, so that you have access to the tumor," Ames says. The problem with this method is that the spinal cord can stop functioning without warning and the patient becomes paraplegic. Another procedure used to access such tumors is to burr a hole in the spinal column anterior to the tumor and suction the tumor out, but the tumor is disrupted and tumor cells may remain behind.

"The main objective of the new approach is to spare neural tissue and to get the tumor out cleanly," Ames says. "The first principle is that we don't do spinal cord retraction and thus significantly reduce the chance that the patient will come out of surgery a paraplegic."

During the surgery, the cervical or cervicothoracic vertebra over the tumor is cut, so that the posterior portion can be rolled back away from the spinal cord. At that point, the table is rotated away from the surgeon to give him a clearer view of the tumor lying under the spinal cord. With clear access, the surgeon can take the tumor out in one piece. The spine is stabilized with a metal framework.

Ames recently described the lateral transpedicular approach in the November 2005 issue of Operative Neurosurgery. UCSF is the only medical center that currently offers the surgery.

Ames has developed another spinal tumor technique for bone tumors affecting individual vertebrae. Rather than cutting the tumor from the bone during the en bloc spondylectomy, Ames removes the whole vertebral section. He cuts the pedicles, then pulls out the front and back sections of the vertebra as a single piece.

"The main intent of the en bloc procedure is to remove the tumor (and surrounding tissue) as a single piece without spreading tumor cells," Ames says.

Ames' en bloc resection can be used for chordoma, chondrosarcoma, osteosarcoma, soft-tissue sarcoma and isolated metastatic disease.

The mechanical structure of the spinal column is retained by a steel framework, which is attached to the spinal column by pedicle screws that Ames also developed. A metal collar protects the spinal cord in the spot from which the vertebra was removed.

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