Ligament Damage from Whiplash in Low Speed Accidents

Written By Advanced Spine Center on February 26, 2016

Ligament Damage After Whiplash!
 
When you are involved in a rear-end auto crash, you can damage your neck.   One particular ligament that you can damage is your Anterior Longitudinal Ligament (ALL).   The ALL is the ligament that runs up and down in front of the neck vertebrae.   The blue tape in the big bone model represents the ALL (see image).
 
Motion x-ray studies of the neck of whiplashed people who are in rear-end collisions, reveal a consistent picture of damage to the anterior longitudinal ligament (ALL).    Corroboration of the observation comes in a 2006 Medical Engineering and Physics Journal report where a group of whiplash researches applied mathematical analysis to study what happens to the human neck and in particular the ALL during a crash.1    A neck spine model is subjected to various forces representing three different speeds, i.e., 5.3, 6.7, and 8 mph, i.e., low speed crashes.  The amount of distraction or displacement of one vertebrae on another is analyzed.    The researcher found that as the speed increased, the amount of displacement increased.  
 
The authors report several findings:
1. The ALL reached stretches that were near the failure rate of the ligament with collisions of just 8 mph.
2. Injuries that do not result in ligament failure may be difficult to diagnose because they could be missed on static X-ray film.  Flexion/extension X-rays or digital motion X-ray could be used to determine the extent of the injury.The authors discuss the potential serious chronic problems that can result from this type of injury:
1. Cervical (neck) instability.   A catastrophic injury of the ALL can result in acute disability while sub-catastrophic injure may lead to chronic pathology.
2. An injured ALL has the highest correlation to extension instability, as well as, axial rotation instability and/or lateral flexion instability.
3. The injuries produced experimentally are similar to clinically observed injuries.
4. Anterior neck injuries caused by whiplash are typically distractive extension injures without exhibiting any neurologic abnormalities.
5. The ALL injury is not visible using conventional radiography and result in cervical instability.
6. Since the ALL is connected to the annular fibers of the disc, a sub-catastrophic failure can result in changes within the disc with long term consequences because of deceased extension stability.
7. The ALL injury makes the neck hyper mobile and unstable that will lead to early degenerative disease of the intervertebral disc or vertebrae.
8. Catastrophic failure of the ALL can lead to disc injury that may require surgical intervention.
 
This study demonstrates the ALL of the spine can be damaged by the injurious motion of whiplash and may lead to long-term disability and/or impairment.   For people who have experienced a rear-end collision, it is advisable to a get a thorough examination to determine the extent of cervical or neck instability and the potential for spinal degeneration later in life.
Unfortunately, the authors failed to report that Flexion-Extension X-rays or the use of digital motion X-ray (DMX) can easily define the translation of one vertebrae on another (called a retrolisthesis) which is caused by damage to the ALL.  The amount of translation reflects the severity of the injury as determined by the AMA Guides to the Evaluation of Permanent Impairment.2
 
If you were involved in an auto accident, get checked out by the doctors at the Advanced Spine Center especially if you think the accident was just a “minor” fender bender.   Careful examination shows some of the most serious neck damage come in low speed accidents.  The current study looks at neck damage resulting from low speeds, e.g., 8 mph and the researchers conclude the ALL is a risk for injury.
 
References:
1.    Stemper BD, Yoganandan N, Pintar FA, Rao RD. “Anterior longitudinal ligament injuries in whiplash may lead to cervical instability.” MedicalEngineering & Physics 2006;28:515-524.
2.     AMA Guides to the Evaluation of Permanent Impairment, 5th or 6th Editions.