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Shaw Chiropractic
A Medical-Legal Newsletter for Personal Injury Attorneys
by Dr. Steven W. Shaw

AMA Impairment Guides: 5th Edition, Part 2

My original intent was to write 3 newsletters on this topic assuming that I could cover enough to wet the whistle of the readers. Based upon the incredible response to date, I will be continuing on this topic until you have lost interest. In keeping with the peaked interest, Dr. Michael Yoel and I have organized a 2 hour presentation scheduled to take place on Thursday, March 31st at the Polytechnic Club. The presentation will be from 3:00-5:00 and be followed by a cocktail hour. During the program, ATransitioning into the 5th Edition@, we will cover topics addressed in the newsletters and more. The course will cost $100.00 per office and will include a copy of the Guides which would cost you $139.95 + $12.95 shipping if purchased from the AMA. We are limiting the books to 1 per office but additional books can be purchased.

Loss of Motion Segment Integrity

A motion segment is defined as 2 adjacent vertebra, the disk, the facet joints and all associated ligamentous structures. As the name suggests, motion segments are movable and each has it=s own normal limits. When the Guides discuss loss of motion segment integrity it refers to alteration in segmental movement resulting in either loss of movement or movement beyond normal mechanical limits. When these limits are exceeded, there is potential compromise of the encased neural structures. When no movement exists, altered mechanical stresses are placed on adjacent motion segments.

The Guides allow for rating of loss of motion integrity. However, the loss cannot be documented by physical examination. Stress radiographs must be performed such as flexion/extension films, joint loading studies or fluoroscopy. Joint translation (shear) in a front to back motion of greater than 3.5mm, 2.5mm and 4.5mm for the cervical, thoracic and lumbar spines respectively indicates loss of motion integrity. Loss of motion segment integrity can also occur from excess angular motion. Motion segment angulations of greater than 11° in the cervical spine and between 15° to 25° in the lumbar spine are considered ratable.

Measurement of motion segment integrity can be done manually. However, the use of computer assisted analysis allows for more specific measurement and is better for demonstration purposes when necessary. Use of Fluoroscopic imaging also provides greater insight into motion segment integrity as it is essentially a video of the spine in motion. With fluoroscopy, motion segment analysis of joint coupling can also be evaluated.

ROM vs DRE

Although I have covered this topic extensively in the past, this edition of the Guides has done an excellent job at differentiating when the "Range of Motion" model (ROM or "functional model") should be used versus when the "Diagnostic Related Estimates" model (DRE or "injury model") should be used. The Guides state that "the ROM method should be used only (1) if the DRE method is not applicable (no verifiable injury); (2)if, after obtaining the history and performing the examination, the physician cannot place the individual within a multilevel DRE category;(3) if multilevel involvement and/or alteration of motion segment integrity has occurred in the same spinal region;(4) if there is recurrent radiculopathy caused by a new (recurrent) disk herniation or a recurrent injury in the same spinal region;(5) if there are multiple episodes of other pathology producing alteration of motion segment integrity or radiculopathy; or (6) if statutorily mandated by the involved jurisdiction"

This means that for the great majority of patients involved in a motor vehicle accident with soft tissue injuries and qualifying findings, a DRE impairment should be used. Those doctors who choose to use ROM impairments because their computer can generate them easily or because the numbers are generally larger should be prepared to justify their actions. On the other hand, when the ROM method is appropriate, it is a far more comprehensive and clinically related evaluation method

If the ROM model is used the evaluation physician should be familiar with the "Specific Spinal Disorders" Chart (Pg 404,Table 15-7) and have used an inclinometer with associated validity testing.