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.