Dr. Lantz pointed out that all chiropractors deal with spinal motion in one form or another, even the so-called "structuralists." "If a bone is 'out of place' or a region has an 'abnormal curvature,' this implies an inability of the bone to move to its proper place or the cure to assume its proper form. In other words, the structures are 'fixated' or otherwise limited in their motions. It all comes down to movement," said Lantz.
One important feature of Dr. Lantz's research is the validation of left versus right movement. Prior to this work, medical researchers paid little attention to these "half-cycle" movements, deferring instead to only report total ROM.
"This is most significant for chiropractic theory," said Dr. Lantz. "Since chiropractic adjustments can be segmentally-specific and side-specific, it is important to look at the effects of such adjustments on left or right movement. Take toggle, for instance. When the atlas is toggled on the right, is movement affected on the left as well? Is only lateral bending affected, or is rotation affected as well? And what about flexion? These are important questions to ask for a better understanding of chiropractic theory and practice."
According to Dr. Lantz, the study began following the World Federation of Chiropractic Conference in Tokyo. He made a presentation at that conference2 in which he raised concerns about "normal" cervical [ROM] values published in a 1991 study by Dvorak, Panjabi, et al.3 Dr. Lantz, then Director of Research at Life Chiropractic College West, had acquired an electrogoniometer and was attempting to replicate the results of that study.
"This is the way science works; when you get a new piece of equipment, you test it out against a standard, and the highest standard for these measurements was the study by Dvorak and Panjabi," commented Dr. Lantz. I tried for a couple of years to replicate their values, but I kept coming up short; not just a little, but 20-30 degrees less for some motions.
"I kept trying to figure out what I was doing wrong. Then, after I had exhausted all sources of possible error, I had to conclude that it was their values, and not mine, that were in error. This was a major assertion. After all, these guys are giants in their fields, and their results were published in Spine. But my findings were undeniable, and the questions raised by them demanded an answer."
Dr. Dvorak is a prominent neurosurgeon at the Schulthess Clinic in Zurich, Switzerland. He is regarded in medical circles as one of the leading "medical manipulators" and has published two books on spinal manipulation. Dr. Manohar Panjabi, PhD, of Yale University, is one of the leading biomechanists in the world, and is best known for his foundational textbook Clinical Biomechanics of the Spine, co-authored by August White, which discusses using an electrogoniometer to measure cervical ROM.
As fate would have it, Dr. Dvorak was at that WFC meeting in Tokyo. He was introduced to Dr. Lantz by Scott Haldeman, DC, MD, PhD, and they discussed the problem at some length. Dr. Dvorak invited Dr. Lantz to come to Zurich to resolve their discrepancies. The two planned the experiment for several months beforehand, with much of the work on the Swiss side done by Geoffrey Klein. The resulting study replicated, in many details, the original study published in Spine by Dr. Lantz in 19992 and, of course, crucial elements from the 1991 study by Dvorak and Panjabi.
The results of the collaboration confirmed Dr. Lantz's assertion that the original Dvorak and Panjabi data were in error. "This isn't one-upsmanship," said Dr. Lantz, "this is about doing good science; it is about the scientific process. This is how disagreements are settled professionally and congenially in an open academic environment."
Dr. Lantz began studying spinal ROM when he realized normative values used in the chiropractic literature and texts, and in the medical literature, were not based on valid research. In many cases, there were no references to any research at all. According to Dr. Lantz, ROM has, in the past, been viewed as unreliable. With new technologies, however, researchers are seeing that spinal ROM determinations can be extremely reliable, if done properly. The resolution of the discrepancies between Dr. Lantz's work2 and Dr. Dvorak's work3 means that researchers around the world, from all disciplines, are moving closer to establishing valid measures for normal spinal ROM.
"Without normal [ROM] values, one cannot determine abnormal or pathological deviations," said Dr. Lantz. "This is very important for chiropractors with regard to rating disability, but can also be useful for tracking the progress of patients, and perhaps directing treatment, once we learn more about spinal motion."
- Lantz CA, Klein G, Chen J, Mannion A, Solinger A, Dvorak J. A reassessment of normal cervical range of motion. Spine 2003; 28(12).
- Lantz CA, Chen J, Buch D. Clinical validity and stability of active and passive cervical range of motion with regard to total and unilateral uniplanar motion. Spine 1999;24(11): 1082-1089.
- Dvorak J, Antinnes J, Panjabi M, Loustalot D, Bonomo M. Age and gender-related normal motion of the cervical spine. Spine 1992;17(10S):393-398.