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Innovations May Ease Process of Back Surgery
Date: Wednesday, September 4, 2002

A pair of “new generation” innovations hold the promise of easing the process of traditional spinal fusion surgery, which essentially welds together two or more vertebrae to ease pain from damaged discs.

By age 50, about 85 percent of the population show evidence of spinal disc degeneration, according to Medtonic Sofamor Danek, the Minneapolis-based developer-manufacturer of medical products for cranial and spinal conditions, including a new fusion technique just approved by the Food and Drug Administration.

Using new bone-building material and a new surgical instrument package, the invasiveness and blood loss of traditional fusion surgery can be decreased dramatically, said Dr. Michael Moore, orthopedic surgeon at PrimeCare’s Bone & Joint Center in Bismarck.

Moore, one of several hundred doctors nationwide trained in the technique, has been waiting for FDA approval of the innovations. Following that approval July 2 (2002), he recently performed his first surgery using bone-generating protein rather than a bone graft.

“Everybody’s heard of bone grafts,” Moore said. “This procedure has the ability to carry out successful fusion without a bone graft.”

Traditionally, spinal fusion surgery is done for people with degenerative conditions of the spine, Moore said. He performs about 150 fusions a year, a procedure also used for spinal fractures, tumors, arthritis of the spine or spinal deterioration from sports or other injuries.

While people can do some things to help this condition—exercise, lifting correctly, etc.—“we inherit our (spinal) cartilage from our parents, and we can’t fix cartilage right now,” he said.

Spinal degeneration may cluster in families, but no one can predict for certain who will get it and who won’t, Moore said.

For some people, low back pain, leg pain or sciatica become so severe and debilitating that they have trouble functioning normally at their jobs and at home.

Spinal fusion once required a large incision, leaving the patient in a body cast for six months to a year. In the last 10-15 years, before this recent approval of bone-generating protein called rhBMP-2 (Bone Morphogenetic Protein) vertebrae were fused with a system of rods and screws. The bone used for the fusion was harvested from the patient’s own pelvis. This harvesting created a second surgical site, subject to pain and discomfort itself.

BMP is a human protein that is cloned, spliced into bacteria and manufactured in powder form. At the time of the surgery, the powered protein is mixed with sterile water and soaked into a sponge-like material encased in a titanium shell. The titanium casing is then implanted between the vertebrae. The BMP protein in the casing then triggers the body’s bone-generating capacity, which fills in the area with the patient’s own bone regrowth.

Clinical trials showed that bone fusion rates using BMP were 6 percentage points higher at 24 months following surgery than traditional bone graft surgery.

Eliminating the need for a second surgery to harvest pelvic bone for the spine helps lessen the magnitude of the surgery, Moore said. Reducing blood loss and pain from a second harvest site are also benefits.

BMP has been in the development stage since 1965 and underwent its clinical trials during the 1990s, Moore said. Orthopedic doctors have been waiting for the protein to be produced and pass its clinical trials, he said.

The other innovation involves sophisticated hardware that by far minimizes the incisions required in traditional spinal surgery. A sextant-like instrument uses a guiding wire, then a series of graduated dilators, to insert arc-shaped rods, all titanium, into the spine with only several small incisions.

The “rod insertion system surgical technique” eliminates the large incision required to get at the spinal column. Instead, the highly calibrated sextant inserts the rods through small (1-2 stitches) incisions, placing the titanium rods precisely into the vertebrae.

With this technique, blood loss from incisions is shrunk dramatically. Moore’s first surgery using the method resulted in minuscule blood loss of 75cc, compared to a range of 500-1,500cc for traditional incisions, he said. This reduces the potential need for transfusions, Moore said.

Robert Hanvik, public relations staff member of Medtronic Sofamor Danek, anticipates at least a fair number of traditional spinal surgeries can be supplanted with this new technique. The new titanium instrument package costs about $7,500, Hanvik said.

Looking ahead, Moore estimates about two hours of surgery time with this technique, compared with 4-6 hours with the older method.

(Reprinted with permission from the Bismarck Tribune.)