Check out this image! What is it?
Yes, it is someone’s back, but how do you know? This is just a series of lines. Somehow, our brain is able to take these lines, and take this 2D image and convert it to a 3D representation of the body. This phenomenon is called Raster Stereography and is the basis behind the way our new Topography scanner works. A computer is able to analyze these lines better than our brains, and gives us accurate measures of spinal deformity.
If we look at the first image again, see if you can notice anything that looks asymmetrical. As you look closer, you start to notice small differences in the contours of the back. Starting at the top, the shoulders are uneven, and the right shoulder blade is more prominent. The muscles on the left of the low back are a little more pronounced, and if you look at the angle of the waist, it is a little flatter on the left.
Go a little deeper and think about what structures under the skin are causing the surface to change in this way. The curve of the spine and bony alignment of the body can have a huge impact on what contours we notice on the surface.
The Diers Formetric Topography machine we recently purchased uses this picture to form an accurate picture of what is going on under the skin. With it, we can determine the curvature of the spine, misalignment of the pelvis, leg length differences, and posture abnormalities, which help us to guide treatment to the underlying problem, rather than just the symptoms.
Why is this important? Why calculate the position of the spine when you can just get an x-ray and see it directly? First of all, x-rays are not good for us, and when a patient needs many spine images, the cumulative effects of x-ray will increase the chances of developing cancer. In patients with spinal deformities such as scoliosis, where many x-rays are needed during the rapid growth period of adolescence, that exposure to radiation causes problems later in life. This technology allows us to image the spine without any exposure to radiation.
Second, it provides a 3D image of the spine. We can get specific measurements of posture and deformity in all dimensions, which helps to guide treatment and develop a more complete plan of care.
Third, the Formetric can be used with movement to determine the effect of specific exercise on the spinal deformity. It gives immediate feedback on whether an exercise is doing what we think it is.
To learn more about topography and treatment for spinal deformity, including scoliosis, visit our services page!
David Butler, Physical Therapist