Source: www.guardian.co.tt
“But how I get dis back pain boy? It jes come on jes so!” muse many bewildered patients with chronic low back pain, attempting to make some sense of their condition. Often, efforts to explain their pain through cause and effect or logic come up empty, and frustration at the difficulty in understanding their condition begins to permeate their lives. Others who have received medical diagnoses may receive some satisfaction about the reason for their back pain. Diagnoses such as “bulging disc,” “spondylosis,” “degenerative disc disease” and “mechanical low back pain” name the condition but seldom provide a complete explanation for what really is happening in their backs. In this second article in my series on low back pain, I will attempt to explain the “nitty-gritty” of this condition. It is my hope that it will shed some light on why it is such a problem, and the importance of treating it correctly, efficiently and diligently. Indeed it is a complicated, heterogenous condition that warrants professional attention.
A breakthrough in the treatment of low back pain began with a genius of a gentleman known as Manohar Panjabi, who has done a lot of research on the subject. Through in vitro experiments, he discovered that the spine could only tolerate less than twenty pounds of load before it collapsed. The passive structures of the spine such as the bones and ligaments cannot support much weight on their own. However, in live subjects, Panjabi found that the spine could handle much more than that, upwards of three hundred pounds. From these observations, he began to realise the importance of the muscular system in the functioning of a healthy back. The muscles are able to give the spine added stability in order to allow the person to lift heavy objects. But just how does this muscular system function to allow us to perform demanding tasks such as lifting? Panjabi developed a hypothesis to explain how the spine achieves stability. It involves three components that have a very intricate relationship with each other.
The first component is the passive structures of the spine, such as the bones and their arrangement, as well as the ligaments that hold the bones together. These structures give the spine minimum stability as we saw in Panjabi’s in vitro experiments. The second component of spinal stability is the muscular system, which when activated can significantly increase the stability of the spine as the muscles contract and hold the bones in a much firmer arrangement. The final component of spinal stability is the nervous system. Let us use the task of lifting a grocery bag as an example to understand the relationship among these three components. The ligaments in the spine contain little receptors that detect the mechanical status of the spine, such as position, the effort required to lift the grocery bag, and the motion of each bone.
These receptors send information via the nervous system to the muscles, telling them what the spine is doing, how much to contract, and in what pattern to contract in order to produce the required stability to lift the grocery bag. The muscles then react appropriately and the grocery bag is successfully lifted without adverse consequences. However, low back pain often arises when this system is compromised. Most of the time, there is injury to the passive structures of the spine, as in the cases of degenerative disc disease, bulging disc, spondylosis, vertebral fractures, among many other spinal diagnoses. Injury to these passive structures also injures the little receptors in the ligaments. As a result, these receptors send incorrect information to the nervous system about the demands of lifting the grocery bag. The nervous system notes a mis-match between the expected requirements of the lifting task and the information it is receiving from the receptors. In essence, it becomes “confused” and relays corrupted messages to the muscles, so that they activate incorrectly. This results in higher stresses on the back and leads to that all too familiar chronic low back pain.
So in summary, low back pain can often arise from a degenerative or traumatic condition. This is the superficial cause. Underlying this, the commanding system of the spine, loses its ability to control the motion of the bones and generate the appropriate muscular response needed to lift the grocery bag.
Indeed it is a very intricate and complicated process, which can go wrong very easily, and become very difficult to correct. It is one of the main reasons why many sufferers will continue to have recurrent episodes of low back pain throughout their lives…unless they are able to retrain this system and make the necessary lifestyle changes, which I will explore in the next and final article in this series.
NOTE: Carla Rauseo PT, MS, CSCS, is a State Registered and Licensed Physiotherapist and a Certified Strength and Conditioning Specialist.