Standardizing how our profession interprets not only the medical information found on an x-ray, but also the biomechanical information, is of great importance. There are medically established biomechanical norms as seen on the x-ray, but no one has proposed a system of standardized markings when looking at films from a biomechanical perspective.

Second, once this biomechanical information is collected, how to apply this to a beneficial treatment program is important. The reason biomechanical x-rays are taken of the lumbosacral spine goes well beyond symptoms in that area. As a major component of the kinetic chain, the L-S spine is both the recipient of other biomechanical imbalances as well as a contributor to all biomechanical imbalances throughout the body.

Figure 1. Simple testing of the medial arches will show symmetry.

The information found on lumbo-sacral x-rays has to be taken in context with all other findings, and the maximum biomechanical potential is always the goal. This potential is contingent upon many factors, so a doctor of chiropractic should never consider a case a "failure" if only limited benefits were reached after a reasonable period of time. Some of the contributing factors that will influence the degree of improvement reached are:

• hereditary factors;
• listening skills on the part of the patient;
• communication skills on the part of the doctor;
• management skills on the part of the doctor; and
• the patient's diet, conditioning, foot type, flexibility, attitude, job, height, weight, shoes, and sleep habits.

Determining the Status of Patients' Feet

A constant factor in the balance of the low back is the balance of the feet. It is imperative to determine the status of the patient's feet, primarily their medial arches, as the support given here will have a long-lasting effect on the ultimate balance and corrections made to the low back. There are two simple tests that will show symmetry, or lack thereof, in the medial arches (Figure 1), and body-weight distribution between the right side of the body and the left (Figure 2). The greater the difference in color, the greater the difference in body-weight distribution.

Figure 2. With the body-weight distribution test, the greater the color difference, the greater the difference in distribution.

Normal Lumbosacral Spine Findings On X-ray

Once the determination is made that there is no pathology present on the x-ray, a biomechanical assessment must be made. Many measurements have been used over the years. However, it's important to keep in mind what the goal is with these assessments. The first goal is to determine the biomechanical status of the patient, and the second is to use the information to motivate and educate the patient in the report of findings. We have found that "fewer" biomechanical measurements makes it easier for the patient to comprehend the significance of these measurements, and it is critical that the patient understands what is being communicated to them so they ultimately will consider going through a corrective program.

The standard series recommended, unless further studies are clinically indicated, are the A-P (Figure 3) and lateral (Figure 4) views.

The following are standardized measurements that should be looked for on every A-P L-S x-ray study:

1. Are crest heights level?
2. Does spinous process of L5 line up with the symphysis pubes?
3. Do the obturators appear equal in size?

The following are standardized measurements that should be used on every lateral L-S x-ray study:

1. Ferguson's gravity line (normal bisects anterior third of sacral base);
2. Sacral base angle (normal is 36° to 42°); and
3. Disk integrity (any wear and tear patterns).

Figure 3 (left). The A-P x-ray. Figure 4 (right). Lateral view. Both views look at several standardized measurements.

Abnormal Biomechanical L-S X-ray Findings

On this A-P x-ray, there are multiple abnormalities that can be identified. Sometimes, these abnormalities can be found together on the same x-ray (Figure 5). As you can see, there is a difference in pelvic heights, a difference in the size and shape of the obturators, and a malalignment between the spine and symphysis pubes.

Interpretation

Clearly, there is a structural imbalance found in all three areas on this x-ray. With the significant difference between the right and left crests, a measurement should be done of the legs to determine if a lift is needed. When the imbalances exist as they do on this x-ray, the capacity of the low back is reduced, making the low back more vulnerable to acute injury, soft-tissue distress, and reduced functionality. When this x-ray is combined with a digital foot scan that shows an imbalance between the left and right weight-bearing (Figure 6), it becomes easier for the doctor to make the recommendation that custom orthotics are needed to start making structural corrections and balances.

Figure 5. Multiple abnormalities are identified, including a difference in pelvic heights.

On this lateral x-ray, there are multiple abnormalities that can be identified. Again, quite often these abnormalities can be found together on the same x-ray (Figure 7). As you can see, there is a posterior Ferguson's gravity line and a reduced sacral base angle. Disk integrity is very good, as this is a younger patient.

Interpretation—Reduced Capacity in the Low Back

When the architectural balance in the low back is altered, obviously there will be a reduced capacity in the low back. This doesn't by any means suggest there is pain or symptoms. However, imbalances typically will lead to increased demands on the soft tissue and disks, leading to ultimate symptoms. Again, when these architectural faults are seen in combination with a difference between the right and left foot on the digital foot scan, the first step taken is to recommend custom orthotics.

Disk Degeneration

This is a very common finding on most people over the age of 45. Disk degeneration can be found before the age of 45, but it is primarily seen in the older age group. Typically, the first disk to degenerate will be L5 (Figure 8), but there are times when L3 or L4 (Figure 9, page 28) will degenerate first.

Figure 6. An x-ray, combined with a digital foot scan, shows an imbalance between the left and right weight-bearing.

Interpretation

When a disk goes through a degenerative process, it is preceded by an increase in mechanical loading. There are two primary causes for this: fixation of a joint due to micro or macro stresses over time, and/or an imbalance in structural weight distribution that is centralized through this joint. These factors create an increased weight load, fixation, and accelerated degeneration of the joint space. The primary goals with a condition like this are the following:

• reduce symptoms;
• restore maximum potential motion back to the involved joint; and
• improve the overall structural balance and center of gravity.

Corrective Program

Using biomechanical findings from x-rays allows the doctor of chiropractic to set objective goals rather than subjective goals for the patient. A corrective program needs to last a minimum of 6 months and can easily be recommended over the course of the year. This time frame is to allow for maximal biomechanical improvement and is determined through a variety of tests.

Figure 7. In this x-ray, a posterior Ferguson’s gravity line and a reduced sacral base angle are noticeable.		Figure 8 (left). The first disk to degenerate is typically L5. Figure 9 (right). At times, L3 or L4 disks degenerate first.

The digital foot scan is an objective test, and the patient can be retested at any point in the future. Re-x-rays are the obvious test of choice to determine improvements, and the examiner must keep in mind that radiographic changes may or may not occur. In the absence of radiographic improvements, it is important to remember that many improvements will still be made, such as joint mobility, muscular conditioning, stability, subjective complaints, etc. The patient also should have a routine of exercises that will be a part of their life.

Conclusion

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Correction of biomechanical findings as seen on the x-ray should be the number one goal of all chiropractors. Fixing the problem, not just eliminating the symptoms, was thrust at us from day 1 in school. Unfortunately, the symptom-based system we now live in has forced many chiropractors to become symptom-based doctors. We need to change that.

When making biomechanical or structural changes, it is mandatory to begin every program with the inclusion of custom orthotics. If the foundation of the body is not addressed, there will be a limited potential for improvement through the course of the program. Once patients understand the role custom orthotics play, the importance of reaching maximum biomechanical improvement, and the work needed to achieve such a goal, most patients will excitedly want to begin the journey that will truly change the rest of their life.

Timothy J. Maggs, DC, is the developer of The Structural Management® Program and travels the country teaching. He can also be heard live on his Internet radio show, Thursdays 3 pm to 4 pm EST at www.StructuralManagement.com.