The Study: Reliability of cervical lordosis measurements on the full spine radiograph.
- The authors compared three different measurement methods on the cervical spine as seen on a lateral full spine film
- They looked at 44 radiographs
- The authors state that "whole-spine lateral radiographs are a key image used in evaluation of global spinal sagittal alignment."
- The three measurement methods studied were: Cobb method, C2-C7 posterior tangent method and sum of posterior tangents method aka the Harrison method.
- The authors concluded that, "All three methods appeared to be highly reliable." But cautioned that you should not use the methods interchangeably as the mean measurement obtained using the Cobb angle was about 7 degrees lower than that obtained using the posterior tangent methods. The differences between the two posterior tangents methods was only about 0.2 degrees.
All three methods are reliable but not interchangeable within the context of a single case “as this could lead to error.”
I leave it to you. Read the article and make up your own mind as to which method you wish to use. I have always heard that the Cobb method is the most used method but in my circle the posterior tangent is the most popular. What I do think is important is that we need to understand the methods that we use to evaluate the spine (I think I said that last issue.). The lead author is from the Department of Orthopaedic Surgery at the University of Illinois in Chicago. It appears that surgeons are interested in measuring spines on full spine radiographs.
Reviewer: Roger Coleman DC
Editor’ Comments: In terms of practical application, there appears to be very little difference between the three methods. That said, it is important to be consistent. So whatever method you start with, just stick with it throughout the case. Many, if not most, DCs are already familiar with the Cobb Method (aka Jackson’s Angle) and it remains the easiest to draw and measure.
For those chiropractors out there who either; aren’t measuring posture on spinal radiographs, OR don’t believe that full spine radiographs provide any real clinical information, OR more commonly, simply aren’t bothering to accurately measure the films you do take, please consider the following excerpts from this study by orthopedic surgeons.
“Spinal balance is critical for physiologic function and low energy expenditure.”
“Sagittal cervical alignment is one of the most important parameters in management of cervical spine disorders.”
“Cervical lordosis (CL) is the most commonly used cervical parameter by surgeons and researchers.”
“Long-cassette lateral radiographs are important in global sagittal balance assessment.”
“On such radiographs cervical alignment can be measured and the relationship between CL and other spine segments can be established.”
“It is thus crucial to use a reliable and reproducible measurement method; one that allows to properly assess the course of the disease and the results of treatment.”
Editor: Mark R. Payne DC
Reference: Janusz P, Tyrakowski M, Yu H, Siemionow K. Reliability of cervical lordosis measurement techniques on long-cassette radiographs. Eur Spine J. 2015 Dec 26. [Epub ahead of print]
Link to Abstract: http://www.ncbi.nlm.nih.gov/pubmed/26707132