Whether a disc herniation is small or large is generally not a measure of size. Rather, it is a measure of mass effect. In other words, are the normal spinal passageways obstructed by herniated disc or not? Are the nerves compressed by herniated disc or not? If the answer is no, then we are dealing with a small disc herniation. Note that there is no size cut off. That is because smaller herniations can have significant mass effect in individuals with congenitally small canals or in smaller individuals.
Radiculopathy is the presence of nerve dysfunction resulting in pain, loss of sensation, altered sensation or weakness. Radiculopathy may be caused by small or large herniations. The presence of radiculopathy is not dependent on the size of a herniation. We will discuss that below.
Small herniation vs disc bulge
Small herniations are quite common, much more so than larger ones. Unfortunately, they are often misdiagnosed as bulges. If your client has significant lasting symptoms and his/her MRI has been diagnosed as having a bulge, consider a second opinion interpretation. If the protrusion occupies less than 25% of the disc circumference it’s a small contained disc protrusion (protrusion is a common form of herniation).
Disc injury and disc inflammation
Outdated medical knowledge, still firmly espoused by defense experts and attorneys, has it that a herniation or protrusion must be large enough to be pushing on nerves to cause pain. This has been scientifically refuted since the mid 1990’s. Science has established that a disc protrusion, even a small contained one, sets in motion a biochemical cascade in the spine. A disc protrusion results in the expression of inflammatory protein molecules, called cytokines. These includes molecules called interleukins, tumor necrosis factor, interferon and colony stimulating factors, to name a few. These molecules signal cells associated with inflammation to migrate to the disc injury site. This results in an ingrowth of microscopic blood vessels and even new nerves. Some cytokines even stimulate the expression of other molecules, like prostaglandins, that maintain the vicious cycle of inflammation. Prostaglandins are very important inflammatory molecules that are inhibited by drugs like aspirin and ibuprofen.
The result of this inflammatory cascade that begins with a tear in the disc is a painful and inflamed disc. With time the disc becomes more painful because of the ingrowth of new nerves, thanks to the cytokines and inflammation. It may take time for the process to occur, explaining why a painful disc may not occur for several days or even weeks after an injury. Often, the inflammation will extend beyond the disc to involve the nerves. The nerves may ultimately become swollen, inflamed and even scarred. When the nerves are affected symptoms referable to nerve involvement will be seen. This may include numbness, pain or weakness of a limb. The patient may develop a typical sciatica pattern and even a positive straight leg raise test. All of this without MRI evidence that the herniation even touches the nerve structures.
Conclusion
Larger disc herniations with significant mass effect are known to result in radiculopathy. However, a herniation does not have to be large to cause nerve problems. modern science tells us that small disc protrusions or herniations can cause radiculopathy, (nerve pain, numbness and weakness). There is now an abundance of science on the subject and even novel therapies that are being developed to target the inflammation. The old adage of mass effect from a large herniation being necessary for radiculopathy has been definitively refuted by science and medicine. It’s time for modern science to be applied to the care of the injured patient and to be properly used to support the causation of symptoms of radiculopathy from a small herniation.
Jennifer Pailey, MD
The views expressed are the personal views of the author and do not represent the views of The Brain, Spine and Joint Group, its managers, affiliates, partners, employees or its clients. Furthermore, the information provided by the author is not intended to be expert or legal advice.
The content of this newsletter is confidential. It is strictly forbidden to copy, forward, reveal the content of or share any part of this newsletter content with any third party, without a written consent of The Brain, Spine and Joint Group. If you received this newsletter, or a link to it, by mistake, please message This email address is being protected from spambots. You need JavaScript enabled to view it. and follow with its deletion, so that we can ensure such a mistake does not occur in the future.