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.