Artificial disk mimics nature to relieve back pain
Turning the rich, black soil for her annual vegetable garden, Stephanie Estabrook was filled with the joy of spring. The sun was shining...
Seattle Times medical reporter
Turning the rich, black soil for her annual vegetable garden, Stephanie Estabrook was filled with the joy of spring. The sun was shining; lettuce, beans and cherry tomatoes were in her future.
Unfortunately, Estabrook sowed more than vegetables that May afternoon.
The shoveling left her with a damaged spinal disk that caused nearly a decade of pain and discouragement, required three surgeries, caused her to miss more than a year of work and, at times, drove her into deep depression.
"Physically, it was the worst thing I've ever been through," said Estabrook, of Verlot, Snohomish County. "And emotionally, it's very upsetting. You can't work, you can't do stuff with your kids, you can't even clean your own house."
In January, Estabrook, 43, became the first person in Western Washington to receive an artificial disk — the latest technology to treat degenerative disk disease, a major form of back pain, one of the most common medical problems. Replacing the damaged disk in her lower back, the new device eliminated the nerve pain that was causing such misery.
Before back surgery
More than 80 percent of people with spinal-disk problems respond to treatment that doesn't involve surgery. Here are some measures that help:
Rest: A day or two of bed rest on a firm mattress can help ease severe back pain. Lying flat on your back with knees bent is most comfortable. Except in the worst cases, you should be up and moving after two days, so your muscles don't lose tone and the pain worsen. Avoid prolonged sitting, bending and lifting.
Cold and heat therapy: Use a cold pack for about 20 minutes several times a day. This could be a gel pack kept in a freezer until use or a bag of frozen veggies wrapped in a cloth. Alternate with a hot pack, heating pad or warm bath, if that seems to help.
Medications: Over-the-counter meds include nonsteroidal anti-inflammatory drugs (NSAIDS) such as aspirin and ibuprofen, which relieve pain and reduce inflammation, and acetaminophen, which relieves pain. In some cases, a doctor may prescribe a muscle relaxer, narcotic pain killer or antidepressant, also to relieve pain.
When to see a doctor immediately
Diskectomy, in which a portion of the disk that is pinching a nerve is removed.
Laminectomy, in which part of the rear part of the vertebra is removed to relieve pressure on a nerve, or to gain access to the disk.
Sources: Mayo Clinic, American Academy of Orthopaedic Surgeons
Long-term alternative?The Food and Drug Administration approved the artificial disk in October for patients with degenerative disk disease at one of two vertebrae in the lower back — and who haven't been helped by more conservative treatment.
Degenerative disk disease involves deterioration, from age or injury, of the disk, the natural cushion that separates the vertebrae of the spine.
Physicians hope the artificial disks will provide a long-term alternative to spinal fusion, where metal rods or cages are surgically implanted to stabilize the spine, relieve pain and induce one or more vertebra to grow together.
Made by DePuy Inc., a Johnson & Johnson company, the approved Charite artificial disk allows more flexibility than a fusion, has a shorter surgical recovery and is less likely to require additional surgery, according to its advocates.
"It's the best advance I have seen in spine surgery in 15 years," said Dr. Paul Schwaegler, one of five Seattle-area surgeons trained to perform the operation. Others are David Hanscom, Reggie Knight, Jeff Garr and Jay Williams.
The FDA based its approval on a DePuy study in 16 medical centers. Researchers compared 205 patients who had received the disk with 99 who'd had spinal fusion. After two years, the safety and effectiveness of the procedures were rated about the same.
On average, patients improved significantly from either procedure in a wide range of categories, including: pain, ability to care for oneself, lifting, walking, sitting, standing, sex, social life and travel. Still the artificial disk isn't always an option. It is not suitable for people with an unstable spine, osteoporosis or scoliosis.
In the DePuy study, significant neurological problems from the surgery — leg pain, muscle weakness or nerve damage — occurred in 4.9 percent of artificial-disk patients and in 4 percent of fusion patients.
The FDA now is requiring the company to study 366 more patients over five years to look at the long-term results of the surgery. The requirement addresses the concerns of many surgeons.
"It's appealing. It preserves motion [in the back]. But we really do need more long-term data on it," says Dr. Robert Haralson, executive director of medical affairs for the American Academy of Orthopaedic Surgeons.
A major cause of painBack pain is the nation's No. 1 reason for visits to the doctor, hospitalizations and utilization of other health services, according to the Academy of Orthopaedic Surgeons. More than 27 million physician visits for back pain — about 10 million for low back pain — were recorded nationwide in 2002, an academy analysis of federal data shows. Specific data on degenerative disk disease is not available, but it is one of the major causes of low-back pain.
Estabrook has been through the wringer. Physical therapy, cold packs and pain medications did little to ease the stabbing, debilitating pain that shot through her back and down her left leg following her disk injury. After a few months, she had a laminectomy, in which part of the vertebra was removed so surgeons could remove the piece of disk causing pain.
The procedure mostly eased her suffering, and Estabrook returned to her human-resources job. But her back still occasionally acted up, sending her to bed for days at a time. Two years later, she re-injured the disk crawling under her desk to access a plug. Over the next three years, despite physical therapy, she went into a slow, painful decline.
Meanwhile, Estabrook moved and got another job — one that also made her vulnerable to re-injury. Sitting next to a secure entrance, she had to reach back to her right many times a day to unlock the door for people. A year-and-a-half ago, she finally had to quit her job and get another laminectomy.
The surgery relieved her pain for a while, but physical therapy did not help her recover fully, and she again went on a downward spiral. This time, the pain extended through her back, hips and both legs, and she dragged her left foot as more nerves became involved. Her doctor was leery of doing a fusion, because there was damage to a second, adjacent disk. Finally, she went to another physician, who referred her to Schwaegler. Approval of the artificial disk would be soon, he told her, and she waited eagerly.
Surgery is demandingDegenerative disk disease, caused by age or injury, results in the disk losing much of its thickness. Like a tire that has lost most of its air, it protrudes outward and the pain from the pressure on a nerve can be excruciating.
Fusion increases the wear on the vertebrae above and below the fused site. Over 20 years or more, that wear may cause the patient to need additional surgery.
Artificial-disk surgery — also called total disk replacement — attempts to mimic nature. It restores the natural distance between the vertebrae and seeks to enable the back to bend naturally. It is also designed to avoid pressure on the adjacent vertebrae.
The three- to four-hour artificial-disk surgery is demanding. Because the disk is on the front side of the vertebra, the surgeon approaches the body from the front to avoid disturbing crucial nerves. Through a 5-inch incision below the navel, the surgeon gently moves aside internal organs and blood vessels to access the diseased disk and remove it.
Next, the vertebra end plates are shaved to make them as flat as possible and allow maximum contact with the new disk. The surgeon then inserts two new cobalt chromium end plates, which attach to the bones with small teeth.
Proper placement of the disk core — made of polyethylene, a common plastic — is crucial. The end plates must hold the core in place but allow it to slide slightly back and forth as the spine flexes.
Positioning determines how well, or if, the patient improves, according to the study the FDA relied upon in approving the device.
"We watch placement of the disk on fluoroscopy, live X-ray, with a picture every five seconds," said Schwaegler.
Physicians who perform the procedure are trained by DePuy, then work further with surgeons in the field such as Schwaegler, who is paid for each doctor he trains.
Surgeons have been implanting artificial disks in Europe for more than 15 years. A 2003 analysis by Dutch researchers of nine studies, involving 411 patients, found that most improved over a relatively short period with an artificial disk. But it cautioned that "there is no evidence" the disks will do well over many years and not cause problems in adjacent disks.
Schwaegler is confident the Charite disk — the third generation of the device — will withstand the test of time.
Still, because of the lack of long-term data, most insurance companies won't pay for it.
"The FDA says they need to do more [long-term] study. We want therapeutic ... procedures for our membership to have long-lasting effectiveness and safety," said Dr. Robert Haskey, a medical director of Regence Blue Shield in Washington.
The cost of the procedure in Seattle is about $89,000, including the device, physician fees and hospitalization, according the Schwaegler. A fusion costs about $70,000 in Seattle.
Estabrook is one of the few patients whose surgery was covered by insurance. And she feels especially fortunate.
"I still can't believe it," she said. "I feel great, better than I have in three years. ... I feel really blessed. I was so frustrated before."
Warren King: 206-464-2247 or firstname.lastname@example.org
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