The Study: Cervical spine alignment, sagittal deformity, and clinical implications: a review
The Facts:
a. The authors reviewed normal cervical alignment, how to measure cervical alignment in the sagittal plane and the effect of cervical misalignment (cervical kyphosis in this case) on health-related quality of life (HRQOL).
b. Recent studies suggest a correlation between cervical alignment as measured on the radiograph and HRQOL.
c. Cervical kyphosis may lead to adjacent segment disease.
d. Cervical kyphosis may create tension on the spinal cord.
e. Cervical deformity correction should include an assessment of global cervical-pelvic relationships.
f. Any forward deviation of skull posture results “in an increase in cantilever loads…”
g. An increase in these loads causes the subject to expend more energy to hold the head upright.
h. The three primary methods to evaluate cervical lordosis are Cobb angles, Jackson physiological stress lines (aka Ruth Jackson’s lines; my note) and Harrison posterior tangent lines. The Cobb angles are the most commonly used.
i. Larger forward translation of the head has been associated with poorer HRQOL.
j. The cervical, thoracic, lumbar and pelvic areas are not independent. The alignment of one affects the others.
k. Interestingly, “thoracic kyphosis is not a result of lumbar lordosis, but rather lumbar lordosis is a result of thoracic kyphosis and pelvic incidence.”
l. Increases in thoracic kyphosis produce increases in cervical lordosis.
m. To evaluate the effect of cervical alignment on the rest of the spine “standing 3 foot x-rays are used”.
n. Cervical kyphosis has been associated with myelopathy. As the degree of cervical kyphosis increases the cord is compressed and flattened.
o. The means of correction that the authors discuss is surgical intervention.
p. “Finally, the future directions of cervical deformity lie in assessing the spine as a whole, including the cervical-pelvic relationships.”
Take Home:
Posture matters. The cervical, thoracic and lumbar spines are not separate and distinct units but instead work together. The sagittal lordosis of the cervical spine can be measured. Cervical kyphosis can affect the spinal cord. Lack of segmental postural alignment results in adjacent segmental disease. Alignment should be considered when looking at the results of spinal surgery.
Reviewer’s Comments:
Although the method of treatment discussed in this article was surgery, the other concepts could have been written by a group of chiropractors. As chiropractors seem to be moving away from embracing spinal alignment improvement as a means to improve the quality of patient’s lives the medical profession seems happy to fill the void. I wonder if there will come a time when the medical profession states that spinal alignment is vitally important but that chiropractors are not needed because they are only concerned with manipulation to improve range of motion and have abandoned their interest in spinal alignment and the use of tools such as radiography to assess spinal alignment. The medical profession can certainly fill the void, unfortunately they seem overly bent on using surgery as the tool of choice. Chiropractic seems to have had the correct premise, we can only hope that it is not taken away by the medical profession or given away by chiropractors.
Reviewer: Roger Coleman DC
Editor’s Comments: Medical research is slowly but surely, stealing chiropractic’s birthright…that structure and function are intimately related. While our profession’s various factions fight to protect their little fiefdoms, science marches on. Unfortunately, that science is now all being done by medical researchers. Chiropractic’s “academic apparatchik” is much too sophisticated to take a serious look at the relationship between spinal posture and function, too hopelessly blinded by a professional self image concerned only with pain relief and completely entrenched in their own anti radiography biases, to begin the process of embracing structural/postural correction as a desirable clinical outcome. But meanwhile, medical researchers have no such problems in seeing the value of structural correction. The only difference is that they are willing to do the research to document why they should be able to take your patients away and do it with a knife. (End of rant.)
Editor: Mark R. Payne DC
Reference: Scheer JK, Tang JA, Smith JS, Ascosta FL Jr, Protopsaltis TS, Blondel B, Bess S, Shaffrey CI, Deviren V, Lafage V, Schwab F, Ames CP; International Spine Study Group. Cervical spine alignment, sagittal deformity, and clinical implications: a review. J Neurosurg Spine 2013 Aug;19(2):141-59.