Lori Allred used to plan her days one step at a time.

Lori Allred used to plan her days one step at a time.

Chronic back pain made even the simplest chores an ordeal. "Vacuuming was an issue," she recalled. "Sitting for more than 20 minutes was an issue. It was bad enough that I had trouble bending over to pick up things."

Allred had degenerative disc disease. One of the spongy, shock-absorbing discs between the vertebrae in her spine had deteriorated. She endured a constant dull ache, interrupted by episodes of searing pain if she turned or bent the wrong way.

So when she heard about a surgery that offered an opportunity for relief, she jumped at the chance.

"When you get to the point where you just can't function normally anymore, why not consider another option?" she said. "What do you have to lose?"

Allred, who lives in Medford, had a prosthetic, stainless-steel disc implanted between her fourth and fifth lumbar vertebrae, near the base of her spine. Dr. Mark Peterson of Medford performed the surgery as part of a clinical trial to evaluate a new device designed to replace failed discs.

The artificial disc basically is two steel plates that slip between the vertebrae after the surgeon removes part of the original disc to create a space. The lower plate has a little dome about the size of a nickel or a dime. The upper plate has a concave surface that mates perfectly atop the dome.

"It's like a teeter-totter," Peterson explained. "It wobbles in all directions."

The wobble means Allred's spine can bend and twist — without pain — just like it did when she was a kid.

"I call it my little Dyson ball," she said, referring to a popular vacuum cleaner that floats on a ball mount.

Peterson said the artificial disc is a huge improvement over spinal fusion — the traditional treatment for degenerative disc disease. Fusion provides relief for some patients, but it puts more stress on the spinal discs above and below the fusion, which can lead to future problems in those discs. Surgeons tend to turn to fusion as a last resort after all other interventions fail.

Peterson said there are other artificial discs on the market, but placing them involves complex surgery and long recovery times. The experimental device he inserted in Allred's spine, manufactured by San Diego-based Nuvasive, can be placed with minimally invasive surgery, which means less pain for patients, quicker recovery and less time in the operating room.

"I have a scar about this big," Allred said, holding her thumb and finger about three inches apart. She was able to go home the same day of her surgery.

Peterson is one of about 15 surgeons across the United States participating in the trial. He traveled to Brazil to learn the surgical technique from the physician who invented the replacement disc. He's done four disc replacements so far, two at Providence Medford Medical Center and two at Surgery Center of Southern Oregon.

While Allred said the artificial disc has changed her life, Peterson cautioned that it's still unproven over the long term.

"What patients all want to hear is how good it is," Peterson said. "The answer is, we don't know. This is a study."

It's also not for everyone. To qualify for the trial, a patient must have degenerative disc disease limited to one disc, and no other spinal afflictions, such as facet disease, which affects the joints that connect the vertebrae. Peterson said he's still recruiting patients for the trial, and those who meet the criteria will have their surgery and follow-up care paid by Nuvasive. The results of the trial will determine whether the device will gain federal approval for general use.

Seven months after her surgery, Allred is an enthusiastic supporter of the technique.

"The only thing I can't do now is run," she said. "I walk two miles on the treadmill every day."

People who want to determine whether they qualify to participate in the trial of the Nuvasive XL TDR should call 541-608-2574.

Reach reporter Bill Kettler at 541-776-4492 or e-mail bkettler@mailtribune.com.