Back pain is usually described as a single problem. This is one reason the medical community has always found it a particular difficult thing to understand. This is akin to saying that chest pain from indigestion and heart attacks are similar. However, if we view it as a symptom with a variety of causes, back pain makes more sense. Understanding different causes allows us to tailor the treatment to the cause.
About 50% of low back pain is disc related. Some of this is mild low back pain, some is moderate, and some is quite severe. The disc is composed of three parts, the tough ligament outside known as the annulus fibrosus (sometimes simply known as the annulus), a jelly-like center known as the nucleus pulposus (likewise simply known as the nucleus), and the top and bottom of the adjacent vertebral bones, known as the vertebral endplates. Disc problems usually have two components, an injury to the annulus, and a movement of the nucleus away from a position centered between the endplates.
Interestingly, research has consistently noted 2 characteristics of disc pain which make diagnosis easier. The first is known as centralization, and as the direction of benefit. Classically, disc pain radiates, or “refers”, down the leg. As disc problems improve, that spreading pain reverses. This is known as centralization, which is a positive sign even if the central pain becomes more intense. It can generally be reproduced by movement in a particular direction, aka the “direction of benefit”. The opposite of centralization, peripheralization, is always worse even if the back pain itself improves. This is because peripheralization happens as the nucleus moves out from a position centered between the bones, and centralization happens as it returns to that position. Peripheralization essentially has two effects: the first is increased tension on the injured fibers of the nucleus, and the second is contact (in one form or another) with the nerves exiting the spine.
With these two characteristics of disc pain, we understand the first step of back pain diagnosis. If the pain centralizes with a direction of benefit, we know it’s most likely disc related. If it does not, we move on to joint dysfunction. In the low back, joint dysfunction is divided between the small joints of the spine, known as the facets joints (or simply, “facets”), and the sacroiliac joints. The sacroiliac joints (or “SI joints”) are the big weight-bearing joints of the pelvis, between the hip bone, or ilium, and the sacrum, the triangular bone at the base of the spine. Both the facets and the SI joints can cease to move properly and cause pain, and are diagnosed with particular movements to specifically reproduce pain from them.
The next category of pain generators in low back pain is nerve pain. With a disc problem, it is very common for the adjacent nerves to be irritated by the disc. This irritation is sometimes inflammatory in nature. However, sometimes scar tissue can develop around the nerve, trapping it in place, and continuing to irritate it with every movement. This is diagnosed with what are called “nerve tension tests”. A normal nerve will not be painful when placed under tension, but an already irritated nerve will. The particular movements to tension each major nerve have been mapped out, and allow us to zero in on the problem more effectively.
The final category of pain generator in back pain is muscular pain. While it is not the most common cause of low back pain, muscles can be the thing which is constantly hurting. Muscle produce characteristic pain referral patterns, and should reproduce the problem when the muscle is touched. The significant detail about muscle-related low back pain is that the opposing muscles are usually involved and must be treated as well, despite generally being pain-free.
In some cases, identifying the painful structure is not enough. In these cases, there is something else going wrong that is perpetuating the pain. A common perpetuating factor is dynamic instability. We define instability as difficulty keeping the body in neutral, and dynamic instability means instability while moving. In these cases, the most effective treatment is exercise designed to stimulate the body’s own protective, stabilizing mechanisms.
The final aspect of this discussion is treatment. Discs (and disc-related nerve problems) respond to two things: pulling the bones apart in a long axis direction, known as traction or distraction, and repeated movements in the direction of benefit. Traction is best performed using a special table called a “flexion distraction table”, and the direction of benefit is utilized in special disc exercises. Joint dysfunction is best dealt with using traditional chiropractic manipulation. This can be done slowly, in what is known as low-velocity low amplitude (LVLA) manipulation, or with speed, in what is known as high-velocity low amplitude (HVLA) manipulation. If nerve problems are independent of disc issues, they can be treated effectively with special movements known as neurodynamics, and are generally performed by the doctor in the office, as well as in a different version at home by the patient. Finally, muscular issues require manual treatment. In our office, we utilize Active Release Technique for this.