Doctors Studying Next Generation Surgery For Back Pain Sufferers

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Doctors Studying Next Generation Surgery For Back Pain Sufferers

Surgeons at Northwestern Memorial Hospital (NMH) are enrolling people with

degenerative disc disease in a research study to determine if new artificial

discs will have the long-term durability to safely provide increased range

of motion and less strain on the adjacent discs than spinal fusion.

Northwestern Memorial Hospital is one of approximately 30 sites around the

country testing the Maverick artificial disc made from cobalt-chrome alloy.

Currently, three artificial discs are being investigated in the United

States. The newest, the Maverick artificial disc, is different in that it

has two rather than three components, which are both made of metal rather

than using any plastics or polymers. Some studies have shown that plastics

and polymers can eventually wear down, and the resulting debris and the

subsequent tissue reaction to such debris is the primary factor limiting the

longevity of joint replacements.

" Artificial joints in knees and hips have been around for decades, but

progress in material engineering and refinement of surgical techniques

finally mean we can attempt disc replacement in as critical a location as

near the spinal cord, " says Srdjan Mirkovic, M.D., a spine surgeon at

Northwestern Memorial Hospital, assistant professor at Northwestern

University's Feinberg School of Medicine, and principal investigator for the

study at NMH.

At Northwestern Memorial, the study is being done collaboratively with

surgeons in both orthopedics and neurosurgery.

The Maverick lumbar disc is made from a cobalt-chrome alloy, a metal

frequently used for orthopedic implants. When assembled, it can move side to

side or back to front. " The concept is borrowed from a concept used in

replacing joints in other parts of the body, " says Liu, M.D., a

neurosurgeon at Northwestern Memorial Hospital, assistant professor at the

Feinberg School of Medicine and a co-investigator for the study. " The

Maverick disc has no plastic parts and uses a simple design with only two

moving parts. We expect this will decrease degradation of the disc and

reduce problems with the mechanics of the disc. "

Fusion, the current standard of care, is performed more than 200,000 times

in the United States each year. " The reason we're looking for alternatives

to fusion is that, while fusing two or more vertebrae in the spine together

can eliminate pain, it does have drawbacks, " explains Dr. Mirkovic. " The

bone does not always heal or fuse correctly, and the recovery and

rehabilitation periods are prolonged. The theory behind replacing the disc

rather than using spinal fusion is that we may be able to preserve range of

motion and decrease wear and tear at adjacent levels by distributing stress

through the lower back. "

As with fusion, the diseased disc is removed. Then, rather than fusing the

surrounding vertebrae together, the Maverick artificial disc is inserted in

its place. A calcium-rich substance anchors it in place. " The recovery may

be quicker because we don't have to immobilize the lower back and wait for

the bones to fully fuse as we do with fusion, " explains co-investigator

Hepler, M.D., an orthopedic surgeon at Northwestern Memorial and

assistant professor at the Feinberg School of Medicine.

Discs are gel-like cushions between vertebrae that absorb shock and act like

ball bearings when people bend and twist. Degenerative disc disease is part

of the natural process of growing older. As people age, their intervertebral

discs lose their flexibility, elasticity and shock absorbing

characteristics. It is a common problem for athletes, but can affect anyone.

The Maverick artificial disc is an investigational device and is limited by

federal law to investigational use. The research study will compare the

outcomes of participants who receive an artificial disc with those of

participants who have lumbar fusion. About two-thirds of study participants

will receive the artificial disc and the rest will receive spinal fusion.

Northwestern Memorial is enrolling participants who have failed conservative

treatments such as medications and local injections for at least six months

and who have pain originating from the disc itself. To learn more, please

visit http://www.back.com/clinicaltrial or contact Northwestern Memorial's

physician referral department at 312-926-8400 or 1-877-926-4NMH (4664).