What does loss of cervical curve mean?

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I want to talk about taking x-rays.  This is a very common diagnostic tool almost always utilized in trauma cases.  For todays article I will be covering Abnormal Static Sagittal Cervical Curvatures Following Motor Vehicle Collisions: A Retrospective Case Series of 41 Patients Before and After a Crash Exposure.  This was published in the diagnostics journal in 2024 by Haas et al. 

Today’s study did spend some time covering the safety of taking x-rays.  They quoted 4 different studies showing that the safety of x-rays for injured patients has been firmly established and fear of x-rays is not warranted.  They reported that quote “failure to use radiography to assess the condition of the spine after injury and prior to treatment could lead to poor outcomes” end quote. 

They discussed another study showing that continued x-rays following an injury can be helpful with continued management of the injury.  There is a lot of fear in the general population about risks of radiation exposure.  These risks have been shown to be extremely low with spinal x-rays. 

Anyone out there that takes x-rays of patients after a motor vehicle collision will understand exactly what this study is trying to show and will not need a study to know it exists.  Attorneys involved with motor vehicle collision cases will also have seen this many times.  This study was done to quote “investigate the possible alterations in the geometric alignment of the sagittal cervical curve” end quote.  It has been my experience that almost 100% of my patients in a motor vehicle collision have a loss of a decrease in cervical lordosis. 

Today’s study reported that a lot of previous studies have been done showing abnormal cervical lordosis with a variety of complaints, but not as a direct result of a motor vehicle collision.  This type of study would be very difficult to perform.  They reported this in their limitations.  There are no databases I am aware of that have patient’s spinal x-rays with no symptoms and no motor vehicle collisions.  All prior x-rays we are likely to get our hands on will be from patients with symptoms.                   

They did just this.  They went to 3 separate clinics and reviewed x-rays taken over the last 2 years.  They included any patients with lateral cervical x-rays who have never been in a MVC.  They then figured out of all of these patients how many of them were later in a MVC and had cervical lateral x-rays taken again.  They excluded from this group of patients people with the following: Spinal fractures, pre-existing spine instability, pre-existing spine surgery, unable to maintain neutral posture for x-ray, duration between examinations of more than 1 year, failure to have a new x-ray within 6 weeks of the MVC, and patients with motor or sensory loss consistent with disc herniation and radiculopathy or myelopathy.  

They ended up having a group of 15 males and 26 females that fit the study criteria.  The age range was from 8-65 years old.  One difficulty of this type of study is to make sure the way the x-rays are taken is reproducible.  They showed that there is a repeatable and reliable positioning method for taking x-rays based on a 2003 study.  This positioning method was used in all 3 clinics.  This method was reported as quote “The patient was instructed to gently nod their head a few times with their eyes closed and to assume a neutral eyes-forward position with their eyes open to prevent sway” end quote. 

As part of the study, they tracked pain scale before and after the MVC.  The pain scale nearly doubled in this study following the MVC.   This study showed that there were no significant changes in cervical lordosis with age or gender.  The ideal angle for cervical lordosis was reported as 34.5 degrees. 

Prior to the MVC the patient had a cervical lordosis of 17 degrees.  Interesting to note that this population had a large decrease in cervical lordosis prior to a MVC.  This study showed that following the MVC there was a further reduction in cervical lordosis of 8 degrees.  This showed that there is a decrease in cervical lordosis following MVCs.  They also looked at instability of translation following the MVC.  4 of the 41 patients did have x-ray evidence of translation that approached instability. 

Now for anyone that regularly takes x-rays of the cervical spine following MVCs you should not be surprised by this study.  I can only remember 1-2 times after a MVC a patient having no loss of cervical lordosis.  The loss of cervical lordosis is objective evidence of injury that now according to the literature is causally related to MVC.   That can be a big deal in litigation.  Now the question is what does this loss of cervical lordosis mean to patients. 

If you have been doing personal injury work long enough, I am sure you have heard something like this in a radiologist report regarding loss of cervical lordosis:  loss of cervical lordosis is due to muscular spasms.  Early research supported this thought of cervical lordosis was lost due to muscle spasms.  This research was published in 1962, 1979 and 1991.  These research articles showing muscle spasms were the cause of loss of cervical lordosis was based on expert opinions. 

More recent research reported that quote “there is no relationship between muscle spasm and loss of cervical lordosis” end quote.  Another more recent study showed that quote “muscle spasm would cause an increased lordosis due to the larger volume and larger moment arms of the posterior extensor muscles of the cervical spine” end quote.  Another study showed quote “found no evidence that hypertonicity and contraction of the cervical spine musculature has a significant impact on shape and magnitude of the cervical lordosis” end quote.   This study shows that it is clear that besides an opinion there is no evidence that muscle spasms decrease cervical lordosis. 

Let’s talk about snap-through buckling.  Snap-through buckling is a model of instability where a system under a load will pass from one equilibrium state to another.  Today’s study reported that quote “snap-through buckling occurs 2-3 times faster than muscles can fully react to a MVC event” end quote.  It can therefore be argued that the cervical spine muscle spasm or hypertonicity is a reaction to an injury and not the cause. 

Today’s study also showed that a loss of cervical lordosis will increase the mechanical stress and strain on the spine.  This increased stress and strain will worsen the range of motion and has been shown to have worse outcomes in the short and long term.  This loss of cervical lordosis will alter the mechanics of the cervical spine.  As we covered in many prior podcasts an alteration of function will lead to degenerative osseous changes. 

In a medical legal case, it is important to document objective evidence of injury or lack of injury.  It is even more important when there is objective evidence of an injury to understand what that means to a patient. 

For my real-world example, I would like to show how loss of cervical lordosis can be used as objective evidence of injury and what that means to a patient.  In a x-ray report when I see loss of cervical lordosis I typically report that there is a loss or decrease in cervical lordosis which is likely biomechanical changes due to the MVC.  I will also typically report that this loss of cervical lordosis and altered biomechanics can leave the spine prone to complications including degenerative changes. 

Fortunately, I have found chiropractic care effective at helping with loss of cervical lordosis.  I see good progress with cervical lordosis, but often not a full resolution.   Following a course of care, I will typically write a final report.  If the loss of cervical lordosis has not resolved I will typically write a report showing that this loss of cervical lordosis has been shown to be associated with worse outcomes in the short and long term.  This is an indication that the following problems are likely to be chronic long-term compilations of the injury: increased stress and strain on the spine, decreased range of motion and degenerative osseous changes.  This is a permanent injury that will alter the function of the spine leading to symptoms throughout the patient’s life.  Patients with these injuries will need management of their spine throughout their life.