Disc Degeneration: Can it be treated with Disc Replacement Surgery?
The person with the most replaced parts wins and now the joint replacement race does not stop with hips, knees or shoulders. Spinal discs are the latest “joints” to undergo a technology overhaul. Disc replacement surgery, also known as disc arthroplasty, is on the minds of millions who have disc degeneration. These worn out parts of the spine generate an avalanche of problems. So why not exchange them for new ones?
Donald has been so worried about his mother’s failing back. Nothing seems to be helping her. One of his friends told him about a new surgical implant that replaces the worn out discs in the spine. Wow! That might give his mother a brand new back and a brand new lease on life. Two years ago, she had her hip replaced. Within months of that surgery, she was back to ballroom dancing. If joint replacement worked for her hip, surely it could work for her back. Great, he calls his mom to share the news.
Not so fast, the treatment of spinal disc degeneration is not so simple. The hip is very different than the spine. The hip is a single ball-and-socket joint that is easily replaced by metal and polymer parts. The spine is a complicated series of three joints: the disc and the two facet joints. Traditionally, intractable spine pain would be treated with spinal fusion–bonding together of one, two, three or more levels of the spine with bone and metal. One of the problems with spinal fusions is the loss of motion which causes a patient to feel like Frankenstein. Another problem with spinal fusions is the extra stress to the discs above and below the stiff fused segment. With these issues in mind, engineers in Europe created artificial discs that would potential reduce stress and preserve motion.
Since the first disc replacement success stories, many types of implants have been developed. The two best studied artificial discs are the ProDisc (Spine Solutions, Inc.) and SB Charite (Depuy Spine, Johnson and Johnson). Overall, many leading spine surgeons remain skeptical because the advantages of disc replacement over spinal fusion are not entirely proven. Maybe the extra stress on the discs above and below the fusion site is really just a natural coincidence that cannot be prevented with an artificial disc? Maybe the ability for the artificial disc to preserve motion is just marketing hype that is really unnecessary for spine health? Ultimately, these questions need to be answered in order to determine whether or not disc replacement is a better surgery than spinal fusion. At this time, the answers remain unclear and the artificial disc remains a controversial subject in the operating room.
Donald does not care about the controversy. He just wants his mother to get “the best” that technology has to offer. Luckily, he has found a surgeon in the area who does disc replacement surgeries. Weeks later, the surgeon finally sees Donald’s mother, but tells her that she is not a good candidate for this type of surgery. Instead, the surgeon offers other options which are better suited for her situation.
One thing that researching artificial disc replacement (ADR) has taught all surgeons is that patient selection is the key to successful outcomes. Only certain patients meet the criteria for disc implants. The best chances for success are for those with a single painful disc, preferably with a disc herniation. Single disc replacements tend to be more successful because those who have had multi-level disc replacement surgery are not as satisfied with the results as those with just one artificial disc. Leg pain, facet pain, and spine instability (spondylolisthesis) are other reasons people are excluded from having disc replacement surgery. In fact, with the current recommendations about patient selection, very few people qualify for ADR. Eventually as the technology improves, the selection criteria will broaden. For now, research continues and more will be learned about the long term effects of a disc implant that has the potential to wear out over time.
Until further research is completed, disc replacement is still experimental in this infancy stage. Like a baby learning how to walk, there have been some bumps and bruises from complications like implant shifting and improper positioning. Because of these technical difficulties, the spine has proven to be much more complicated than hips, knees or even shoulders. Surgeons and patients must proceed with caution and with a clear understanding of the issues such as: patient selection, long term effects, complications, satisfaction rates, and alternatives. Overall, the goal for any surgery is too improve a patient’s ability to live comfortably. Maybe surgery is not the best treatment option on the horizon for disc degeneration? Maybe surgery is not the best option for a particular individual? All the options need to be considered carefully before jumping on the joint replacement bandwagon because the person with the most replaced parts does not necessarily win.
Christina Lasich, M.D., wrote about chronic pain and osteoarthritis for HealthCentral. She is physiatrist in Grass Valley, California. She specializes in pain management and spine rehabilitation.