In our office we utilize both posture and x-rays to evaluate your spinal alignment. While a postural analysis can provide a knowledge of gross postural/spinal abnormalities (your outside alignment), only a radiographic evaluation can provide the details of your spine’s alignment and condition (your inside alignment). Your spinal alignment, any possible spinal arthritis, and disc disease (S.A.D.D.) are both conditions of interest to your doctor. With the knowledge from analyzing your spinal x-rays, the doctor can determine a beginning clinical impression (diagnosis from any abnormalities found on your x-rays) and determine an initial program of corrective care.
What is Normal for the Spine?
Doctor Bagley performs several levels of analysis on your spinal x-rays. First, an overall evaluation of your alignment in front-to-back radiographic views along with your side radiographic views are performed. In the front view, your spine should be straight or vertically aligned with gravity. In the side view, your spine should have four natural curves. These four curves should be a convex forward curve in the neck (termed lordosis), a concave curve in the rib cage area (termed thoracic kyphosis), another convex forward curve in the low back (termed lumbar lordosis), and a concave curve in your sacrum-tailbone area. Figure 1 illustrates this alignment.
Normal spinal alignment is depicted in both the front and Side views. In the front view, the center of mass of the skull, thorax, and pelvis are in a vertical line which falls between mid-stance. The spinal column is vertically aligned with respect to gravity. In the side view, the center of mass of the skull, thorax, and pelvis are in vertical alignment over the ankle. The cervical spine is lordotic, the thoracic spine is kyphotic, and the lumbar spine is lordotic.
Ligament damage is present when a spinal vertebra does not align properly with either the vertebra immediately above it or immediately below it. In the 1 st and 2nd picture, abnormal alignment of a vertebra translating left and right, signifying spinal ligament damage, is illustrated for the front view. In the 3rd picture, in the side view, forward slippage of the top vertebra is depicted. In the 4th picture, in the side view, backward slippage is shown.
For a third evaluation of your spinal x-rays, your doctor checks each vertebra for normal contour and density. This evaluation determines the state of any possible spinal arthritis and disc disease (S.A.D.D.) that you may have. Figure 3 provides an example of this analysis.
For a fourth evaluation of your spinal x-rays, your doctor checks the spacing between each pair of vertebrae. This spacing is where the spinal discs lie. Any narrowing of the normal spacing indicates disc injury and disc disease. Figure 4 presents an example of disc narrowing and disease.
Between the top and middle vertebrae, a normal disc spacing is seen. However, between the middle and lower vertebrae, the disc space is narrowed. This indicates that the disc has been injured and is losing its water content. While disc disease can have several causes, generally, it is a result of abnormal stress (pressures) applied to the disc from abnormal spinal alignment.
For a fifth evaluation of your spinal x-rays, your doctor determines the alignment of each spinal region (neck, rib cage, and low back) compared to the region immediately below by comparing each region to a vertical line in both the front view and side view. The following vertebrae should be vertically aligned with each other: Cl (first neck vertebra), Tl (first rib cage vertebra), T12 Hast rib cage vertebra at the level of your kidneys), and SI (first vertebra m your sacrum). Figure 5 illustrates this alignment For the three separate spinal regions, neck, rib cage, and low back.
Normal spinal balance from the side is when a vertical line will pass through Cl, Tl, T12, and S1. This can be observed all at once on a full-spine side view x-ray or for individual regions on smaller x-ray views, termed sectional x-rays. The figure to the left shows only the posterior points of each vertebra. If we look at the side view cervical (neck), Cl is aligned with Tl (thick vertical black line), with a forward convex curve termed cervical lordosis. If we just look at the side view of rib cage (thoracic), Tl is aligned with T12 and there is the presence of a concave curvature (termed thoracic kyphosis). If we look at the side view lumbar (low back), T12 is aligned with SI, with a forward convex curve termed lumbar lordosis
For a sixth evaluation, your doctor measures any displacements of the individual spinal vertebra and/or spinal regions. These measurements are in degrees for any angular or turning (rotational) displacements and in millimeters for any sliding or shifting (translational) displacements. Figures 6 and 7 illustrate these measurements.
In the front x-ray views, lines are drawn through the centers of mass of each spinal vertebra to measure your abnormal spinal alignment. In A, an example of an analysis of abnormal spinal alignment of the neck in the front view is provided, and in B, an example of an analysis of abnormal spinal alignment of the low back is shown.
In the side view, lines are drawn on the back part of each spinal vertebra. These lines are termed “Posterior Tangents”. When measuring angles between adjacent posterior tangents, the angles are termed Relative Rotation Angles (RRA). When angles are formed by posterior tangents on the top and bottom vertebrae in any spinal region, these angles are termed Absolute Rotation Angles (ARA). There are precise normal values published in the scientific literature for each spinal RRA and each spinal ARA. Your alignment will be compared to these published normal values.
What Are the Risks of X-Ray Exposure?
While we must constantly work towards the reduction of health risks in all endeavors, we may be led to accept a minimal level as normal. While there is no data indicating diagnostic radiology has a present risk, any radiation dose must be compared to the benefits of useful information gained. The necessity for appropriate treatment selection is indeed an acceptable trade-off when put into perspective. The need for x-ray imaging is especially clear when one considers that radiographic (x-ray) imaging is the only valid method for determining abnormal spinal alignment and the presence of any spinal degeneration. However, since 1990, there has been a growing knowledge base that suggests medical x-rays may have health benefits. While an actual benefit from radiation exposure may seem outrageous, mere is much scientific evidence for this phenomenon. This phenomenon/field of study is termed Radiation Hormesis. 12-27,29-48
Radiation Hormesis is the stimulatory or beneficial effect of low doses of ionizing radiation. This topic is in direct conflict with the “Linear No-Threshold Hypothesis” (LNT), which has been assumed to be true for more than 50 years. This LNT model comes from estimating the risks at lower doses of radiation, in the absence of data, by extrapolating in a linear model from the extremely large doses of radiation from atomic bombs dropped on Japan in the 1940s.
This LNT model has been used to set limits of radiation exposure by all official and governmental associations around the world. 17 Recently in 2003, Kauffmanl2 reiterated that authors critical of exposure from diagnostic radiation always use the LNT model. This use of the LNT model includes the recent 2005 report by the USA National Research Council.28 This report stated, “there will be some risk, even at low doses (100 mSv or less), although the risk is small” and “there is no direct evidence of increased risk of non-cancer diseases at low doses.”28 This 2005 report ignored and contradicted an earlier 2003 review by Kant et al.29
For a comparison of exposures, USA citizens are exposed to an average annual natural background radiation level of 3 mSv, while exposure from a chest x-ray is approximately 0.1 mSv and exposure from a whole body computerized tomography (CT) scan is approximately 10 mSv.28 Also it is noted that lOmSv = l,000mrem, which equates to about 46 cervical series or 8 lumbar series. Thus, the x-ray views taken to evaluate your spine in this office constitute a very small exposure compared to a CT scan or even annual background radiation from your natural environment.
Thus, it is obvious that the extremely small health risks (and maybe even some health benefits), associated with the x-ray exposure, needed to determine the state of health of your spine in this report, are small indeed compared to the knowledge gained from this information.
From your radiographic examination at our office, we have determined the state of degeneration of your spine, and have determined the exact displacements of your spine. This knowledge not only gives us a working Clinical Impression/diagnosis of your spinal condition, but also determines the type of treatment that is needed to improve your spinal health condition.
We hope that you appreciate our thoroughness in examining and diagnosing your spinal health problems. In the next few pages, for each x-ray view obtained, we will present a normal view on the left hand side to compare to your x-ray on the right hand side. A table of values of normal measurements and your abnormal alignment will be provided on a summary page after the x-ray photographs.
By Jarrod Bagley, D.C.