The Study:  Sagittal alignment of the cervical spine: do we know enough?                 

The Facts:

a. The authors note there is growing interest in correlating clinical outcomes to cervical sagittal alignment.

b. The authors state it is “known that cervical lordosis is not universally physiological and should not be pursued in all patients undergoing surgery.”

c. They indicate that the interaction between lordosis, kyphosis and translation and the cervical and whole spine balance affects outcomes.

d. The authors also note that our understanding of cervical sagittal balance has grown in the last decade

e. They feel it is not the shape of the cervical spine by itself but how the shape works with the balance of the entire spine.

f. The authors then move through a series of discussions, some of which are regarding the changes in sagittal alignment seen following spinal surgeries. Although the discussions are somewhat wandering, they do provide background and the interested reader may wish to read them in the full text..

g. The authors note that cervical sagittal alignment is important and must be considered when performing cervical spine surgery, our understanding of the role of cervical sagittal alignment remains “primitive”.

i. They state: “Patients with pre-operative cervical kyphosis with sagittal imbalance are known to have worse outcomes post-operatively. It is unclear whether and to what extent correcting this imbalance should be pursued, as it must be shown to result in clinically superior outcomes. A greater understanding of its relationship with overall global spinal balance will also be required in order to accurately determine personalized surgical correction targets for individual patients.”  

Take Home:

Sagittal alignment of the spine is important to corrective care surgeons (and should be to us as well) and yet there simply isn’t enough known about it at present.  We need more research to improve our understanding as to what are appropriate goals for sagittal alignment in surgical interventions.

Reviewer's Comments: This article points out the interplay between the shape of the cervical spine and the rest of the spine. This is a big deal and we do have a lot to learn. Once again we are seeing continued interest by the medical community in the sagittal alignment of the entire spine. It would be interesting to see the results if spine surgeons took a lateral full spine view before deciding on how to proceed when contemplating surgical intervention. Would it change the interventions they used? Would they actually use the full spine view to inform their decisions?

Reviewer:  Roger Coleman DC

 Editor’s Comments: I found it interesting that the authors are already thinking in terms of being able “to accurately determine personalized surgical correction targets for individual patients.” They are obviously thinking forward to eventually providing surgical corrections of posture which are individually tailored to the unique spinal characteristics of each patient. It seems tragic, that chiropractic, a profession with such a rich heritage in the relationship between spinal alignment and health, cannot even come fully to grips with the much more generalized concept that there can be no normal spinal function without healthy spinal alignment. This paper is one more example of how we are being left in the dust in this crucial area of spinal research.

Editor: Mark R. Payne DC 

Reference: Teo AQA, Thomas AC, Hey HWD. Sagittal alignment of the cervical spine: do we know enough? J Spine Surg. 2020 Mar;6(1):124-135. doi: 10.21037/jss.2019.11.18.  

Link to Abstract: https://www.ncbi.nlm.nih.gov/pubmed/32309651

Link to Full Text:  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7154352/pdf/jss-06-01-124.pdf