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Ligament Injury: A Hidden Injury in Spinal Trauma

 

This guest post is brought to you by my friend and colleague Dr. Francisco Colon. Dr. Colon has been doing a lot medical-legal speaking on the role that ligament injury may play in pain after spinal trauma. He was kind enough to share a bit of his expertise in finding these soft tissue injuries that many physicians may be missing on a routine work up. You can find out more about Dr. Colon and his practice at his practice website Cordero Family Chiropractic

Ligament damage to the knee is something most of us have heard of in some regard. Either from personal experience or somebody we know. Detecting ligament damage to the knee is fairly easy to do. Any physician MD, DO, DC and most experienced nurses can easily test for ACL, PCL, and lateral ligament stability by applying basic orthopedic tests. Knee injuries are also well understood and addressed by health care professionals. In that regard, if you develop or acquire a ligament injury to the knee odds are any competent practitioner can easily test for, and send out for the right diagnostic images in order to get conclusive evidence. Unfortunately, this is not the case for ligament injury of the cervical and or lumbar spine.

Doctors have been playing around with x-ray technology since mid-to-late 1890’s. And we have a lot to show for 120 plus years of application and research. And since very early on physicians understood the role x-ray technology would play in detecting ligament damage to the spine. In fact, according to Yochum & Rowe’s Essentials of Skeletal Radiology: “In 1919 A. George called attention to the relevance of ascertaining alignment to detect post-traumatic cervical injuries”. When spinal anatomy is not in proper alignment with George’s line we call that a “break” or “step deformity”. In more scientific terms this is known as an anetrolisthesis or retrolisthesis depending on whether a vertebra slid forward or backwards in reference to the segment below it.

George's line

George’s lines drawn on a neutral lateral cervical x-ray. Looking for signs of a break or step.

As seen in the illustration George’s line can be seen from a side or lateral view of any portion of the spine and normally has an arch like shape. Since the moment it was described by A. George and in his book “A Method for More Accurate Study of Injuries to the Atlas and Axis” we have understood that there are 4 reasons and only 4 reasons for a break in this line. These are: dislocation, fracture, ligament laxity, and degenerative changes. These reasons have not changed since 1919. And the one we will focus on today is ligament laxity as a result of trauma.

Spotting Hidden Ligament Injuries

The most common reason for ligament damage to the knee is forceful trauma. It is the exact same for the ligaments of the spine. But unlike the knee, damage to the ligaments of the spine have  much more severe consequences and are the likely result of acceleration-deceleration injuries such as whiplash. More so, the American Medical Association indicates that “when routine x-rays are normal and severe trauma is absent ligament alteration is rare” (page 379 Guides to the Evaluation of Permanent Impairment 5th edition). In other words it takes a significant amount of force to overstretch and damage these ligaments. The AMA guides go on to say that when there is a break in adequate alignment and “severe trauma” is present flexion and extension x-rays are indicated.

George’s line is useful in identifying really gross ligament injuries, but remember that ligaments are supposed to hold things together in movement. If you sprain an ankle, the ankle doesn’t hurt nearly as much when it is neutral, but it hurts a whole lot when the ligament is stressed by movement. We can’t rely strictly on a neutral x-ray for ligament injuries, so we have to see what they look like when the neck moves.

Flexion and extension x-rays images taken of the side of the spine while the region (cervical, thoracic or lumbar) is in full flexion and also in extension (bending forward and bending back). From a practical standpoint this is the best way to stress the stabilizing ligaments of the spine. In the knee we can easily stress ligaments by manually applying pressure as it is a single superficial and large joint. Unfortunately the spine is not as easily tested and to avoid checking ligaments of the neck through the use of the “choke-hold method” a true professional will opt for x-rays.

 

Flexion stress x-ray may reveal injury to the posterior longitudinal ligaments

Flexion stress x-ray may reveal injury to the posterior longitudinal ligaments

 

 

extension x-ray

Extension stress x-ray may reveal injury to the anterior longutitudinal ligament.

It is also important to note that unlike the knee MRI and CT are will not show ligament damage as 99% of these images are taken in a neutral and recumbent position. This position will not stress the ligament structures enough to elicit evidence of Alteration of Motion Segment Integrity (AOMSI). In fact, standard trauma screening protocols miss discoligamentous injuries in an acute setting at a rate of 44% when CT is present and normal according to Alhilali and Fakhran. In a 2015 study titled Delayed or Missed Diagnosis of Cervical Instability after Traumatic Injury: Usefulness of Dynamic Flexion and Extension Radiographs, by: Gi Yeo, Jeon and Woo Kim discuss the following:

“In discoligamentous injury, 30%of patients with ligamentous disruption displayed a negative result on static radiographies and CT scan…Dynamic flexion extension radiographies are often recommended for patients complaining of neck pain or tenderness after an acceleration-deceleration mechanism injury, especially for patients presenting persistent symptoms in the absence of abnormal findings on standard 3-view radiograph including antero-posterior, lateral, and open mouth views…”

And they conclude:

“Dynamic flexion and extension radiographies are required to exclude the possibility of cervical instability in the patient with cervical trauma in initial or follow up studies. However the examination should be performed carefully to avoid neurologic deterioration.”

In short, the literature suggests that trauma protocols currently have many short comings and the knowledge practitioner should utilize dynamic flexion extension studies to document ligament damage. Concern for neurologic deteriorating has great validity as discussed in the British Journal of Radiology by Harison and Ostlere 2005 “Timely diagnosis of these injuries is imperative, as risk for neurologic sequelae is 10 times higher in patients with cervical injury missed on initial screening.”

The proposed mechanism for neurological deterioration that is expected with these injuries was evidenced and documented in a 2006 SPINE article by Nabili, Jiayong, Quaise Et.AL whereby it was documented that every millimeter of retrolisthesis allowed by ligament instability represents a 12% encroachment in the foramen. It is therefore evident that this hidden injury of the spine one that is very common place in trauma, one that is very easily overlooked and one with severe implications when undiagnosed.

Dr. Francisco Colón was born and raised in Puerto Rico. Dr. Colón decided to study chiropractic at Life University in Marietta, GA. In his last year of studies Dr. Francisco was part of a selected delegation of chiropractic students and Doctors that traveled to a hospital in China to educate and to provide chiropractic care. After graduating Life University in early 2010 Dr. Francisco moved to Miami where he practiced for 3 years with one of South Florida’s most successful chiropractic centers. Dr. Francisco has served a wide range of patients from the new born and healthy to the high performance athlete and the ill. He is committed to his new community of the Palm Beaches and will work hard to preserve the high quality of care that patients have received and have grown to expect from Cordero Family Chiropractic.

Looking at the Brain in Chronic Whiplash Injury

Injuries occurring after a motor vehicle collision can lead to chronic head and neck pain long after the damage of the injury is done repairing. These patients are generally classified as having chronic whiplash associated disorder (cWAD). A problem with cWAD is that we don’t really have a strong sense of why some people will get chronic pain after the injury while most will recover seemingly unphased.

Years of research studying biomechanical changes, ligament studies, and MRI changes in the neck have yet to show a diagnostic lesion that is predictive of a poor prognosis in whiplash patients. A number of studies have shown that psychosocial factors like work status, gender, and attorney retention appear to have a stronger correlation to chronic pain than any current medical diagnostics. This has allowed critics to say that chronic whiplash may be more psychosomatic than a true pathology. 1

How Whiplash Can Change the Brain

Conventional thought on whiplash has linked the pain of whiplash to a soft tissue injury in the cervical spine. When the neck undergoes rapid acceleration and deceleration, then the ligaments, muscles, and tendons of the cervical spine can be sprained and strained with varying levels of severity.

Instability of the cervical ligaments can lead to chronic pain in some trauma cases, but many patients who have chronic pain after an accident don’t have this level of injury. Many of these patients may even have close to normal imaging findings. Even in patients that have positive imaging findings, there’s not much difference between the imaging findings of those that will get better on their own and those that will have long lasting pain. 2

It’s easy to understand how injuries to muscular and ligamentous tissue can cause pain, but chronic whiplash injury is about more than just neck pain. Chronic whiplash often includes things like migraine headache, vertigo, and cognitive decline which are similar symptoms to mild traumatic brain injury. At least one study has shown that whiplash and concussion are indistinguishable based on symptoms alone. 3

When pain is poorly related to tissue injury, then it becomes more helpful to start thinking about pain as it relates to the brain itself. It’s easy to understand how the whipping of the head can tear and injure ligament and muscle tissue, but we have to dig a little deeper to see how whiplash can affect the brain.

Altered Cerebral Blood Flow

One of the best ways to see how a brain is changing is to monitor the way your brain uses blood. These studies are done using things like PET scans that help to identify areas of the brain that are gobbling up more glucose which tells us how active that part of the brain is at a given time.

Patients with chronic whiplash symptoms showed differences in blood flow in the brain in specific areas that play a role in how we perceive pain. These areas include the anterior cingulate cortex, insular cortex, medial prefrontal gyrus, and parahippocampus. 5

This is important because it tells us that the regions of the brain that are affected are NOT just the regions that perceive pain. Areas like the insular cortex and medial prefrontal gyrus are areas that aren’t directly responsible for feeling pain but are related to the limbic system and help us build context around pain.

If there are changes to the way these brain regions are wired, then we may also lose some of our ability to contextualize and inhibit our conscious perception of pain.

Image Source Unknown. If this is yours please contact us so we can credit you or remove.

Image Source Unknown. If this is yours please contact us so we can credit you or remove.

The belief amongst these authors is that there is a mismatch between the incoming pain stimulus and the level of activation in the pain processing centers of the brain.

Axon Injury

This mechanism is pretty similar to what can happen with a concussion. When the head and neck accelerate and decelerate during a collision, the force of the head and neck moving can be stopped by a seatbelt, but it won’t not stop the brain from moving inside the skull. As the brain shifts forward and back, it can create a shearing force in the brain and damage the neurons deep within the brain. The forces from an accident like this have been shown to be similar with the forces associated with a football concussion. 4

Whiplash and the Brain

While the force may not be enough to cause a concussion, the force profiles of a concussion and whiplash are likely high enough to cause some axon injury in the brain.

Although axonal injury doesn’t really correlate well to pain, it can impact our balance, postural control, vision, and other systems that help to keep us upright in a healthy way. Breakdown of these systems can help make sense of why whiplash patients can have vertigo, concentration problems, and headaches.

Central Hyperexcitability

Imagine if you sprained your ankle playing basketball one day, but weeks later after your ankle should have healed, you start to feel pain in other areas of your body that had nothing to do with the ankle sprain. This is the phenomenon of central sensitization which is caused by hyperexcitability of the neurons in your spinal cord. Although just one part of the body was injured, the effects of a central hyperexcitability is that you may feel increased pain throughout your body as a whole.

When we describe the injury of a whiplash as a sprain/strain, then it should have more in common with a sprained ankle in terms of tissue damage and repair. We expect sprains and strains to feel close to normal again in 4-6 weeks for minor sprains. However, the pain of a minor whiplash can last months. Why?

The way the body reacts to injury of a central structure like the spine can be a lot different than the way it responds to a distal structure like the ankle or wrist. When you injure your neck and back, your nervous system perceives movement as more catastrophic because there’s a chance that injury can occur to the spinal cord. Your CNS brings your pain neurons closer to their firing threshold so that they fire easier. By doing this, it is more likely to make movement more painful and immobilize you because your pain receptors will fire more easily. Immobilizing an area of injury is one of the main purposes for pain, because tissue repair is harder for the body if you have  a cut or broken bone moving around all the time.

That’s why when you go down with a neck or back injury, you can be really cautious or apprehensive about any type of movement. Your brain is playing defense against you out of fear that your next movement may be catastrophic to your survival. This may be your body’s wave of keeping you immobilized until the inflammatory and repair response is over.

This becomes very problematic when your central nervous system retains this hyperexcitability AFTER the injured tissues have healed. It leads to a condition where you are feeling pain everywhere, but there’s no blood test or imaging to point to why you are hurting.

This is probably the most important reason for chronic pain, not just in whiplash, but we see this in conditions like fibromyalgia or post-surgical pain syndromes. This isn’t a new idea either. Researchers have shown that central sensitization is a player in whiplash dating back to the early 2000’s. 5, 6

Changing How the Brain Perceives Pain

We know now that the brain and central nervous system can be re-wired in a way to cause chronic pain through a concept known as neural plasticity. We also know that neural plasticity can be used therapeutically to help make the brain more resilient and sometimes undo this maladaptive pain response.

Part of this means that we have to change our mindset about the nature of pain. Our patients yearn for a specific lesion with tissue damage to point to as the culprit for their pain. That way, if we get rid of the lesion, then the pain should follow suit. The obvious problem with this is that there may be no lesion at all. For some this will lead to despair and hopelessness, but for others it may lead to unnecessary procedures to cut or inject areas that are NOT the reason someone is hurting.

 

So if someone’s chronic pain is not coming from a pinched nerve, strained muscle, or injured ligament what is a doctor supposed to do for an ailing patient?

We have to engage patients in things that will change how the brain interacts with pain stimuli. Here’s a short list of useful strategies:

  1. Flip the script – Patients in pain are scared of movement because they think they are creating more injury. We can talk to our patients about this. If we have a level of confidence that pain is coming centrally, then we can teach patients not to fear their MRI or fear their movement. We can teach patients that moving their bodies may be painful right now, but they are NOT causing greater injury despite their pain. By giving patients a better sense of control over their bodies, their pain status can start dropping just by changing their mind.
  2. Lean into it – Patients consistently surprise themselves with how much pain they can tolerate as long as they know they aren’t harming themselves. Exercise and movement therapies can be powerful ways to affect central pain issues. Lots of people focus on doing exercise that help you avoid pain, but people with sensitization issues may benefit from leaning into the pain a bit. By gradually exposing the nervous system to movement with tolerable amounts of pain, you can train your body to tolerate that movement by desensitizing the fear response to that pain
  3. Adjust the Brain – most people and even many chiropractors attribute the benefits of chiropractic care to removing physical pressure on pinched nerves. This might be true in some cases, but it’s not the reason people with chronic pain syndromes get relief. A focus of chiropractic research in the past 10 years has studied how adjustments can change the way the brain processes sensory information.7, 8, 9When we combine these central changes from adjustments with movement therapies, we can make a big change in the way a person’s brain responds to movement.
  4. Biofeedback Tools– A unique way of addressing sensitization after whiplash is to use tools that provide real time feedback as a way to shift the brain’s attention on a painful area. Things like neurofeedback therapy with EEG, visual feedback with attached lasers, and wearable biofeedback devices allow the brain to shift it’s focus to another powerful stimuli. This provides a positive reinforcement to the patient to show that they can gain greater control over how pain shows up in their lives.

Closing Thoughts

The ability of our brains to change and adapt is an important piece of the rehabilitation process. While the above therapies are things I use in clinical practice on a day to day basis, these aren’t the only things that can help you recover. Our brain changes and adapts to ALL stimuli, and finding the right fit that works for you is the job of a good clinician.

  1. Dufton JA, Bruni SG, Kopec JA, Cassidy JD, Quon J. Delayed recovery in patients with whiplash-associated disorders. Injury. 2012 Jul;43(7):1141-7. doi: 10.1016/j.injury.2012.03.006. Epub 2012 Apr 2. PubMed PMID: 22475071.
  2. Curatolo M, Bogduk N, Ivancic PC, McLean SA, Siegmund GP, Winkelstein BA. The role of tissue damage in whiplash-associated disorders: discussion paper 1. Spine (Phila Pa 1976). 2011 Dec 1;36(25 Suppl):S309-15. doi: 10.1097/BRS.0b013e318238842a. Review. PubMed PMID: 22020601; PubMed Central PMCID: PMC3248632.
  3. Leddy JJ, Baker JG, Merchant A, Picano J, Gaile D, Matuszak J, Willer B. Brain or strain? Symptoms alone do not distinguish physiologic concussion from cervical/vestibular injury. Clin J Sport Med. 2015 May;25(3):237-42. doi: 10.1097/JSM.0000000000000128. PubMed PMID: 25051194.
  4. Elkin BS, Elliott JM, Siegmund GP. Whiplash Injury or Concussion? A Possible Biomechanical Explanation for Concussion Symptoms in Some Individuals Following a Rear-End Collision. J Orthop Sports Phys Ther. 2016 Oct;46(10):874-885. PubMed PMID: 27690834.
  5. Curatolo M, Petersen-Felix S, Arendt-Nielsen L, et al. Central hypersensitivity in chronic pain after whiplash injury. Clin J Pain. 2001 Dec; 17(4):306-315.
  6. Curatolo M, Arend-Nielsen L, Petersen-Felix S. Evidence, mechanisms, and clinical implications of central hypersnsitivity in chronic pain after whiplash injury. CLin J Pain. 2004 Nov-Dec;20(6):469-476.
  7. Bialosky JE, George SZ, Horn ME et al. Spinal manipulative therapy-specific changes in pain sensitivity in individuals with low back pain. J Pain. 2014 Feb; 15(2):136-148.
  8. Lelic D, Niazi IK, Holt K, et al. Manipulation of dysfunctional spinal joints affects sensorimotor integration in the prefrontal cortex: a brain source localization study. Neural Plast. 2016; 2016:3704964.
  9. Haavik-Taylor H, Murphy B. Cervical spine manipulation alters sensorimotor integration: a somatosensory evoked potential study. Clin Neurophysiol. 2007 Feb; 118(2): 391-402.