In a fascinating new study just published in The journal BMC Evolutionary Biology, researchers have discovered a possible relationship between one of the most common causes of back pain—disc herniation—and the shape of the spine.
Now, that may not seem all that exciting or extraordinary, but the researchers found that people who have back pain often have a lesion known as a “Schmorl’s node” lodged in between the bones of their spines. And here’s where their research got very interesting: they also report that the spines of people with chronic back pain tend to be closer in shape to the spines of chimpanzees than their human comrades.
In other words, back pain sufferers may have gotten the short end of the evolution stick!
Could it really be that people who suffer from back pain just don’t have spines that have evolved as much as those who live life back pain free?
Schmorl’s nodes occur as a result of strain or stress on the spine. They are essentially spaces in the vertebrae where the cartilage slips into the surface of the vertebral body, often causing inflammation, pain, and difficulty walking. As we evolved from four-legged creatures to upright humans who could walk on two feet, our spines had to evolve to accommodate our new physiology and locomotion. But perhaps some of us (which would actually be a good portion of us since more than 80 percent of us will experience back pain someday) have backs that are stuck in an ancient relative from the chimp family and haven’t fully evolved yet to human standards that can handle the pressure of walking upright.
It’s an intriguing theory to say the least. It’s even gotten a name: the ancestral shape hypothesis. This hypothesis may also explain some other spinal diseases like osteoarthritis. The researchers plan on examining the spines of more ancient and modern humans to further study the notion. And I can’t wait to read about it.
Many folks who log on to our web site write us because they’re concerned that the development of chronic neck pain seems to affect their general quality of life. This correlation is intuitively obvious since anyone who has chronic pain would by the nature of that pain have an overall sense that the quality of their life is less than it should be.
This association was recently documented in a very interesting study by Nolet and associates from the Department of Health at the University of Alberta, Canada and Lakehead University in Ontario, Canada. The primary authors were chiropractors who routinely work with the patients with neck pain.
This study included 1100 randomly sampled Saskatchewan adults with new onset of neck pain. When participants were interviewed six months after the onset of neck pain and asked to take a test called the health-related quality of life test (HRQoL), it did in fact document that chronic neck pain is a predictor of poor physical quality of life. This study was published in the Spine Journal this year (2015).
Anterior cervical discectomy and fusion (ACDF) is popularly regarded as one of the most successful surgeries performed on the spine. You can learn a great deal about this procedure by watching this video from my partner, Dr. Seth Neubardt.
ACDF demonstrates not only a high success rate in improving preoperative symptoms but also has a very favorable safety/complication profile. Patients tend to tolerate the procedure well with relatively little postoperative pain and increased mobility when compared with some other commonly performed spinal operations. In an important article in a recent issue of Spine Journal, Dr. Burneikiene and associates asked and attempted to answer an important question: Is there an optimal timing to further perform surgery?
The findings of this study are instructive and important for Dr. Neubardt and myself as we routinely care for patients with this diagnosis.
That study suggests that patients who have surgery within six months of the symptom onset were associated with much better relief of their radicular, i.e. arm pain, but there was not a significant difference in the resolution or diminution in their neck pain. The criticism of this study is clear in that they did not distinguish between patients who had pure radicular, i.e. arm pain and those who had arm pain with neck pain or those who had neck pain alone.
Our suspicion is that those patients with true radicular symptoms will do best with earlier surgery, particularly if they develop evidence of weakness or loss of sensation or the pain is of such severity that it has limited their ability to function.
Patients who present with cervical myelopathy, in the context of multiple sclerosis, may have overlapping symptoms that result from or are accentuated by both conditions. In fact, I recently had such a patient in my office and the question arose as to what is the impact of surgical intervention and the prognosis for meaningful recovery among individuals with concurrent multiple sclerosis and cervical myelopathy. Unfortunately this data is not well known.
A recent article by Daniel Lubelski and associates published in The Spine Journal discussed just this problem. They followed 48 patients over a 15-year period and unfortunately the majority of patients who had surgery demonstrated no significant improvement in a variety of long-term scores.
Dr. Neubardt and I discussed this issue and it is our goal to better understand the occasional patient who has cervical myelopathy with both these diagnoses in the hopes of helping patients improve their symptoms.
A common question posed to those of us treating cervical herniated discs is the role of physical therapy as a way to treat the herniated disc. The other modalities that frequently come into question are the role of manual therapy or traction. The bone and joint task force on neck pain and its associated disorders published in European Spine in 2008 by Hurwitz, Carroll LJ et al. determined that manual therapy and exercise did seem to provide some benefits to patients with cervical radiculopathy (pain, numbness or tingling down the arm) while traction and various passive modalities did not offer benefit beyond usual care. In our own experience, we find Physical Therapy useful in those patients who have either preoperatively and/or postoperatively developed specific muscle weakness. Many of those patients end up having surgery, but physical therapy does play an important role in the return of muscle strength. Although to the best of our knowledge, we know no randomized trial evaluating the effects of physical therapy during the postoperative period following cervical spine surgery.
A common problem that we face in our practice treating cervical herniated discs is of those patients who present with cervical myelopathy. Myelopathy is compression of the spinal cord by disc or osteophytes (bony ridges).
Generally, there have been two well-accepted treatment modalities to approach this problem. One is ananterior cervical discectomy and subsequent fusion. That is a procedure that will decompress the spinal cord from an anterior approach followed by fusion.
The second common operative procedure is what is called a posterior laminoplasty. With that procedure, the spinal cord is decompressed by opening up the bone in the back of the spinal canal called the lamina.
It has been debatable as to which approach is preferable in patients with cervical myelopathy. It was then with some interest that Dr. Sang et al from the Singapore General Hospital reported on a prospective two-year study of patients treated either with multilevel anterior cervical decompression and fusion with plating or posterior laminoplasty. This was published in an excellent peer-reviewed journal called The Spine Journal in 2013. The results demonstrate that patients with multilevel cervical myelopathy when treated with laminoplasty do well and compared favorably with those patients treated with an anterior approach with a followup of two years.
They report the posterior laminoplasty surgery was associated with a shorter operating time, better range of motion, and the tendency towards fewer complications. They also conclude that a larger randomized study needs to be done to support these findings.
This study is important because so many surgeons and patients alike are faced with the option of one or another approach.
In some instances, the most direct approach to the upper cervical spine is through the oral cavity. One of the challenges of the transoral approach has been the possibility of infection because the mouth is clearly not a sterile area. A recent paper by Dr. Shousha in the journal Spine reports that the infection rate is 3.6%. This is much less than had previously been thought and puts into greater perspective the risk for those patients who require this approach.
One of the most common issues that arise in our practice is well discussed by Dr. Neubardt in the educational video and relates to the choice we the surgeons and US patients have between an anterior cervical discectomy with fusion versus an artificial disc also called an arthroplasty. It has been noted that with cervical spine fusion and the passage of time, adjacent disc level seemed to deteriorate faster. On the simplistic level, this may represent the fact that with two vertebrae fused the adjacent levels have to do more of the “work.” The rationale therefore with an arthroplastic mobile device is that it would decrease the incidence of adjacent segment disease. Therefore, one of the most elementary issues to ask is, what is the incidence and rate of the development of adjacent segment disease? Most studies would indicate that with the single-level fusion, the rate of an adjacent level developing degeneration is 1% per year. Those studies would also indicate that it is more likely to see adjacent segment disease in those patients in whom that the adjacent level already demonstrates some evidence of degeneration.
One of the possible complications of either an anterior cervical discectomy and fusion and/or artificial disc replacement is damage to the vertebral artery. A recent paper by Courtney O’Donnell in the journal Spine concludes that the course of the vertebral artery varies very little (less than 1.5%). Based on that finding, she and her colleagues feel that a CT angiogram prior to surgery is unnecessary. This paper is important in that it will obviate the need for many patients to undergo the angiogram procedure. That test can now be deemed unnecessary.
Adjacent segment disease being the appearance of degeneration of the disc at the level either above or below a fused disc level, so what that means is if someone had a disc degeneration and fusion at C5-C6, it was generally considered that the adjacent segments, i.e., C6-C7 or C4-C5 would be more likely to develop this degeneration. This concept was in large part the basis of why we were so excited about artificial disc replacement because by preserving motion we hope that the adjacent disc would not degenerate or certainly not degenerate as fast. This actually may be a non-issue. A recent article on comparing anterior cervical discectomy and fusion, artificial discs and found no difference at least not in a short-term followup. So, I think it is best if you have been considered for disc replacements or motion preserving device– that is to say an artificial disc versus fusion– that you discussed this with your surgeon reviewing carefully the pros and cons.