Low back pain is the No. 1 chronic pain complaint among Americans, according to the National Center for Health Statistics. In the 2006 survey, more than one in four respondents said low-back pain was a chronic problem. An estimated 31 million Americans between the ages of 20 and 64 experience frequent back pain lasting a full day or longer.

Until recently, Sandy Hoyer was among them. The Ashley resident was in her mid-50s when low-back pain began affecting her ability to lead an active life. X-rays showed degeneration of the discs in her lower spine, as well as wearing down of the small facet joints that link the bony vertebrae together. This led to a narrowing of the spaces through which the spinal nerves run. The compressed nerves caused back and leg pain, weakness and numbness.

“It got to where I couldn't even go to our little grocery store in Ashley without making it through the checkout in tears. I couldn't stand up straight,” Hoyer, now 66, recalled. Chiropractic treatment helped, “but not for long-term. “Acupuncture helped to a greater extent, but I had to do it every week,” she said.

In late May, Hoyer became the second patient in Indiana to have implanted in her lower back the Acadia Facet Replacement System. Doctors Kevin Rahn and Robert Shugart are leading the Acadia clinical trial team at Fort Wayne Orthopaedics, the only Indiana research site for the investigational device made by Hopkinton, Mass.-based Facet Solutions Inc.

About 20 sites across the nation are participating in the clinical trials. Data from the current trial will be used to gain final Food and Drug Administration approval for general use.

When first diagnosed, Hoyer was told surgery was an option, but it was not without drawbacks and complications. Traditional surgery involves trimming or removing the bone spurs and diseased facet joints, then fusing together adjacent vertebrae to stabilize the spine. But spinal fusion limits the natural motion of the back.

Another problem with spinal fusion is that, although the fused vertebrae are supported with surgically-implanted hardware, the vertebrae above and below the fused area can pay a toll from bearing the brunt of motion and weight, weakening over time, which leads to compression of spinal nerves in that area as well.

Significant advancements have been made in recent years in large joint replacements, such as hips and knees. But progress has been slow going and more complicated with spinal facet-joint replacement, Rahn said.

The Acadia system, which is made of cobalt-chrome and titanium, enables the joint to be decompressed widely. By restoring range of motion and fully stabilizing the vertebrae with the implants, the hope is that damage to adjacent joints will be less than with fusion.

“We've had excellent results and no complications,” Rahn said of the five patients at FWO who have received the Acadia system. Candidates must have moderate — not advanced — disease; have tried other non-surgical therapies first; and met other health criteria. Participants must be able to meet a set number of pre- and post-operative visits.

For the surgeon, implanting the Acadia system “is more tedious” than doing a fusion, Rahn said.

The procedure takes about three hours, followed by a two- to three-day hospital stay. FWO, with main offices at 7601 W. Jefferson Blvd., hopes to do about 20 such implants. While a few private insurers cover implantation of the device, FWO works with Facet Solutions to ensure qualified patients can access the investigational treatment.

Data released in April from the pilot study of Acadia showed significant improvements of all measures for patients, including 88 percent reduction in disability, 77 percent reduction in back pain and 83 percent reduction in leg pain.

Hoyer says she is more than satisfied: “I have no nerve problems, no sciatic pain. I can bend over and touch my toes,” something she has been unable to do for years. “They told me to walk as much as I can. I've even jogged a little.”

At the height of her pain and disability before surgery, she sold her beloved horse, thinking her riding days were over. Now she says, “I'm looking forward to riding again.”