For some doctors, the world of impairment ratings creates fear and anxiety. Or, on the other end of the spectrum, an adrenaline surge, and battle-ready emotions. Little is taught in most chiropractic colleges on impairment ratings and how they impact the life of a patient and reflect on the competence of the DC caring for the injured patient. This series of blogs will not only help you get in the game but will give you the tools to stay at the top of your game for years to come. If you have not read Part 1 and Part 2, you are going to want to go back before you read part 3 which dives into the importance of a good delivery.
Now that we have covered the basics of why it is important to get in the game and follow the Guides, we are going to look at how to deliver an effective radiology-based impairment rating report using The AMA Guides®, 5th or 6th Edition. Key areas of The Guides where DC’s have special emphasis include spinal impairment of the various regions: cervical, thoracic, and lumbar spines, as well as the pelvis. The focus here is on the section with the spinal impairment chapters for the regions of the spine. The Guides describe in detail AOMSI – alteration of motion segment integrity.
This AOMSI radiographic finding is only accepted by The Guides to be visualized on plain film lateral flexion and extension views also known as motion studies. Let us address the cervical spine as an example. You do not use MRI or CT for determining AOMSI. The measurement is determined by assessing how one vertebra slips forward or backward on top of another vertebrae as measured on the lateral flexion and extension views. The measurement is obtained by placing points/dots as shown on the diagram and determining how many millimeters does the anterolisthesis or retrolisthesis occur, if any. The measurement in millimeters is the amount of slippage. (Image 3) This isknown as translational AOMSI.
A value greater than 2.5 millimeters in the thoracic spine or greater than 4.5 millimeters in the lumbar spine, and greater than 3.5 millimeters in the cervical spine qualifies as a loss of structural integrity.AOMSI can be either a loss of motion segment from increased translation or angular motion or both.1
In the 6th edition, the AOMSI measurement for the cervical spine is described as the translation measurement being greater than 20% anterior or greater than 20% posterior to the relative translation of one vertebra on another. This AB ratio measurement is shown on Image 1.
There could also be angular AOMSI whereby the vertebrae are tipping or angulated in a flexed or extended position by more than 11 degrees over the other adjacent vertebrae. (Image 4) The instruction is too long for this article but is clearly described in the Guides.A line is drawn along the posterior bodies of the vertebrae below and above the motion segment in question on dynamic flexion and extension of the lateral x-rays of the spine.
Angular motion AOMSI of more than 11 degrees greater than each adjacent level on the flexion radiograph onlyqualifies the individual for this ratable impairment. Alternatively, there may be complete or near complete loss of motion of a motion segment due to developmental fusion, surgical arthrodesis, or preserved motion with disc arthroplasty.2
The subtle differences between the 5th and 6th Editions requires determining which one your state allows or which one you are more comfortable in measuring if both are allowed.While this may seem complicated, it is quite simple once you invest one hour in reading the AMA Guides® spine chapter and watching a 10-minute tutorial on how to apply the lines to perform the measurements. Advanced software with AI technology that allows the doctor to take about 3 minutes and place a dot on the 4 corners of the vertebral bodies of C3 thru C7 on the lateral flexion and extension views will create the measurements automatically for either 5th or 6th Edition measurements. Once you use the digital x-ray software to place those dots/points, then the calculation and measurement are performed by the software and the determination of a ratable impairment are established into a narrative radiology report.
Part 4 of this series will look at the final steps in delivering an effective radiology-based impairment ratings report. Make sure to catch up on Parts 1 and 2 of this series before moving on; you do not want to miss a single step!
Permanent Impairment Ratings: