If something sounds too good to be true, then chances are it probably is not so good after all and should be monitored with a watchful eye. All eyes in the spine community have been watching the results of many trials related to total disc replacement for low back pain. In a recent review, members of the Cochrane Collaboration have rendered a warning about the effectiveness and safety of total disc replacement for low back pain.
The idea of replacing a worn out spine disc was first introduced in 1966. Because of very poor results from this pilot procedure, the idea was put away until the technology could catch up. In the past two decades, several disc replacement concepts have come knocking on the FDA’s door: CHARITE (DePuy Spine) and ProDisc (DePuy Synthes Spine) are approved by the FDA and the Maverick (Medtronic) and Flexicore (Stryker Spine) are in the investigational stages. The difference between them is in the amount of movement each one will allow with the ultimate goal of preserving spine flexibility, relieving pain, improving function, and reducing the risk of adjacent level degeneration.
The issue of adjacent level degeneration has been a hotbed of controversy in the spine surgery world. One of the primary problems with conventional spine fusion is that the adjacent levels above and below the fusion are subject to a great amount of stress and wear out very quickly after the fusion takes place. With the use of total disc replacement technology, surgeons are hoping for a device that will preserve enough range of motion so that adjacent levels will not be subjected to so much stress.
While the hopes are high, the results of the initial investigations and trials are subject to review. Members of the Cochrane Collaboration are famous for reviewing the literature and rendering statements about the medical evidence. This time they set their sights on the total disc replacement technology. In terms of effectiveness for treating low back pain, total disc replacement is no better than conventional spine fusion in the short term. Even though the total disc devices preserve range of motion, there is no evidence that proves that these devices prevent adjacent level degeneration. And because the studies used highly selective patient criteria, meaning that only the young and healthy are implanted with these devices, nothing can be said about whether or not total disc replacement should be made available to the general public.
The Cochrane review team continued with their assessment by addressing safety factors. Since this technology is relatively new, no one knows how these devices hold up in the long run, over a course of a lifetime. Thus, long-term follow-up should be watched carefully for potential harmful effects and complications that may arise twenty to thirty years later. Furthermore, nothing in the current medical literature really accounts for the possibility of these devices needing to be revised or replaced. And like all surgery techniques, the risks for infection, bleeding and other complications are known to occur.
As the members of this jury weighed the medical evidence, they came up with this verdict:
"Because we think that harm and complications may occur years afterwards, the spine surgery community should be prudent about adopting this technology on a large scale, despite the fact that total disc replacement seems to be effective in treating low back pain in selected patients, and in the short term is at least equivalent to fusion surgery."
This verdict hinges on two key phrases: "should be prudent" and "on a large scale". Yes, the medical community needs to be very careful about adopting new technology. Decisions to treat should be informed and sound based on the available medical evidence. And at this moment, not enough is known about total disc replacement to start slamming them into everyone who has low back pain "on a large scale". As a doctor, I would only recommend a total disc replacement to a young, active, healthy individual who has severely debilitating one-level disc degeneration. As a young, healthy, active individual with persistent back pain, I would have to be pretty desperate to get my life back on track before I’d let a surgeon touch me.
For now, the medical community will continue to investigate and evolve this concept of replacing worn out spine discs while the community of individuals with back pain sits in the galley with high hopes of a miracle. Sometimes wishes that are too good to be true do come true.
Spine (Phila Pa 1976). 2013 Jan 1;38(1):24-36.
Specialist in Pain Management and Spine Rehabilitation