Early methods of classification for low back pain were based on either anatomical findings, restrictions of movement, or assessing alignment of body landmarks. Many of these classification still are in use today.
Classification By Positioning
There are many therapists, chiropractors, and osteopathic physicians that will palpate (using the fingers to sense or find things) bony landmarks on either side of the spine, or on one side of the spine and centrally on the spine, and then assess their alignment with each other. Treatment is then based on the relative position of the fingers as they line up on the patient.
The main pitfall for this type of assessment is the inherent asymmetry of the human body – both the patient’s and the examiner’s. For example, I spent my college undergraduate days working in physics laboratories. In those labs, we measured with very accurate and precise (there is a difference between those two terms) devices, and were measuring fairly definite objects. A common scenario was measuring the length of a piece of metal (or the length of travel between two objects made of metal) with a metal ruler or measuring tape.
In each and every case, we would measure three times and take an average. Why? Because the alignment of our eyes, head, measuring device, and object being measured changes from moment to moment. On the human body, the examiner is using the inherent asymmetry of his/her own eyes, hands, shoulders, arms, etc to attempt to get a measure of relative positions of multiple body parts on the patient. Each of these landmarks are bony prominences, which must be located through layers of skin and fat. Never mind how the patient and examiner might be standing, leaning, or otherwise orientating their bodies.
Studies of this type of assessment found:
- The examiners were unlikely to agree on the relative positions of bony prominences when examining the same patient.
- The examiners were unlikely to agree, therefore, on what kind of problem the patient was having, or what classification their problem fell into.
- The patients’ symptoms were reduced by spinal manipulation, regardless of what the examiner felt was wrong, or which direction he/she felt the manipulation should be performed.
Classification By Anatomic Abnormality
With the advent of advanced imagery physicians attempted to relate problems seen in the clinic with the results of more technologically advanced imaging studies, such as MRI. For instance, a patient had pain that radiates down the right leg, with numbness of an area of skin and weakness of a group of muscles associated with a particular nerve root, the examiner would look to the imaging study (MRI in most cases) to confirm that the nerve root indicated by clinical exam was indeed the one with some kind of abnormality (usually impinged upon by another structure) demonstrated on the MRI.
Sometimes this is a smart practice. When pain radiates down the arm or leg and presents with a fairly specific pattern that correlates to a large disc herniation, then the MRI can indicate to a surgeon what structures will need to be surgically altered or removed. In other cases pain is localized to the center of the back, or radiates only into the gluteal area (butt) or upper thigh. Imaging studies may not show any abnormality, or may show an abnormality that doesn’t correlate with the problem observed in the clinic.
For instance, a patient comes in for right-sided back pain that radiates into the middle right thigh. MRI is performed and demonstrates a small disc herniation on the left side that is impinging on a nerve root on the left side. Subsequently several research studies were performed on “normal” people – those that had never had any significant back pain. What did they find? Roughly speaking, the subject’s age predicted the percentage likelihood that person would demonstrate a significant abnormality (disc herniation) on the MRI. That is, in a group of 100 adults at age 40 who have never experienced any low back pain (a difficult group of people to find, by the way), roughly 40 of those adults will have a herniated disc revealed on their MRI.
There were those clinicians (physicians, chiropractors, therapists) that believed that based on the location of the pain, quality of the pain (burning, stabbing, etc) and what movements increased the pain, they could determine what anatomic structure (disk, joint, or otherwise) was injured or painful. Subsequent research demonstrated that clinical examination could not accurately correlate findings with a particular structure in the back or sacroiliac joints. Even if an examiner did know what was wrong (but remembering that they never could accurately know), there was still no agreement regarding what kind of treatment to pursue. What does one do to fix a disc rather than a joint or ligament?
What came along next -through decades of observation and quite by accident at first – was the classification of patients by syndrome. A syndrome is a group (some call it a “cluster”) of signs (what the examiner observes or provokes) and symptoms (what the patient complains of) put together. The use of syndromes usually indicates that scientists do not understand the underlying mechanisms of the problem, or that the underlying mechanisms may relate to each other in such a complicated way that they are not easily understood.
Some common syndromes are chronic fatigue syndrome, restless leg syndrome, or lately two that have been “redefined” a little – metabolic syndrome, and acute coronary syndrome. They sometimes are “redefined” from specific anatomic or physiological problems when it becomes apparent that the particular structure or physiological pathway is only part of a larger problem. For example heart attacks are related to coronary artery disease, but through a much more complicated process than was realized 20-30 years ago. The same goes for diabetes, obesity, and high blood pressure – some components of metabolic syndrome.
In spinal pain, the first syndrome classifications were a combination of complaints of pain and loss of function, combined with assessment of position. Then in the 1950s Robin McKenzie, a physical therapist from New Zealand, began to look at spinal pain a different way – classifying mostly on reports of what activities increased or decreased the patient’s pain, along with the pain response to repeated end range movements. This process was started when a patient was accidentally placed into a position (extreme extension – lying face down with the back arched as far as it would go) that was thought to be damaging to the back.
The patient got off the table (after falling asleep) and reported that he felt much better. Where other therapists, including McKenzie, had been afraid to ask a patient to push himself to the limit of a painful motion (bending backwards, for example) he found by accident that repeatedly pushing the spine to it’s limits in a given direction can tell a lot about what can solve the patient’s painful problem. Keep reading for future articles on this issue with more specifics about how your therapist can accurately classify and treat your spinal pain.