Academy of Chiropractic’s Lawyers PI Program

Lawyers and Medical Specialists Meeting-Communication #27

From the Desk of :

“Alteration of Motion Segment Integrity”

Raymond Wiegand, D.C.

Dear Doctors, 

You are a group of a few who understand the need and are willing to use science to document soft tissue injuries. Structural engineering, physics and mathematics easily explain the biomechanical stability of the spine and motion segment.  As I process x-rays I keep information on the type of ligament instability (rotation / translation) and the location. The most frequent instability occurs at C5. This results from a flexion extension injury where the curve reverses direction so fast that it avulses the infraspinous and supraspinous ligament. This mechanisms is complicated by other forces that work to the detriment of the high impulse distortion to the cervical curve.  Other sudden impact injuries like falling backwards and hitting your head presents many of the same injury dynamics.

Ligament avulsion is easily explainable by the science of biomechanics. The motor unit rotates on an instantaneous axis of rotation (IAR) located posterior to the back of the vertebra body.  The IAR represent a point of pivot from which objects rotate around. The further away from the pivot the more distance the surrounding soft tissue has to elongate to accommodate the rotation. Time plays an important factor on how the ligament responds. The typical time of an impulse during collision is less than 100 milliseconds. This suddenness of force exceeds the physical properties of elasticity and micro or macro avulsion occurs.   

I’ve collected data on the biomechanics of the spine for 30 years including motion studies. One observation, patients are more injured in more locations than anyone could imagine. And the long term effect is destabilization, tissue failure, degeneration and loss of function with pain. We are lucky that the Guides recognizes this injury and that it is based on numbers not opinions.  The numbers are important prior to treatment because it alerts the doctor of appropriate treatment and documents the injury and potential impairment. When AOMSI is detected, for legal purposes, to be an impairment it has to be stationary and permanent. That means, following clinical intervention no further improvement is expected. To document this, the study must be repeated at the end of treatment. This applies to the cervical and lumbar regions. Seat belts are particular injurious to the lumbar spine and lower thoracic spine due to anchoring (lap belt) and rotation (diagonal shoulder belt). 

The Guides is a salvation to objectively document injury and validation for treatment by chiropractors. There are less objective measures but they don’t carry the weight of a Guides impairment.  I will be writing a paper for publication the first half of this year with regards to AOMSI to support the rationale and need for treatment. Hard science is the salvation for chiropractic. 

I am moving to a life changing event by changing my work focus so that I can dedicate my time to teaching spine mechanics and processing films for Spine Metrics.  I am trying to make a difference before our profession throws out the inherent science of clinical spinal biomechanics and abandons the x-ray analysis. To that end I will stop treating patients after 33 years and give up my active clinical practice. I will sincerely miss the patients but the reward comes from knowing I’m teaching doctors how to treat thousands of patients with the best available information. Science and technology easily supports our chiropractic philosophy by describing the rationale and need for spinal adjusting. 

To this end I need your help. I need each one of you who have been sending films to Spine Metrics to send at least 6 studies a month. If you are not sending films check out the service at And don’t short change the patient by sending only cervical films, the lumbar region is nearly as susceptible to AOMSI as the cervical region.  If the patient case is a third party action, you may be the only one who can properly document the most ratable injury. Patients will be dealing with their injuries for a life time. We need to helps them get the settlement they deserve.  Please review your forthcoming files and if appropriate, have the x-rays analyzed. It’s a win win for everyone.  

I will also be available for continuing education for your state. I have presentations for CE for 4,8,12,16 and 24 hours.  If you can help sponsor a seminar through your state association it would be greatly appreciated.  I just need contact information and I will do the follow-up.  Thank you for your anticipated help and I hope the review above of injury mechanism is helpful. 

Raymond Weigand DC