A Chiari malformation (CM)—also commonly referred to as cerebellar ectopia or Arnold Chiari malformation—is a structural defect in the lower-rear portion of the brain (cerebellum). This is the part of the brain that controls balance. CM is most commonly caused by a congenital defect. In fact, doctors were sure that developments before and directly after birth were the only possible causes of the malformation. However, several recent studies have shown a correlation between a traumatic incident (i.e., auto accident or slip-and-fall) and symptomatic CM. In other words, a Chiari malformation can be asymptomatic for an indefinite period of time until a traumatic episode instigates its symptoms. For lots of injury victims, this comes as surprise since most individuals with an underlying Chiari malformation have no idea they even have it. Now, research is coming out that may suggest that trauma can not only awaken CM symptoms, but actually cause the malformation altogether.
A Chiari malformation is a structural defect, in this case an enlargement, of the cerebellum. Normally, the cerebellum and the upper portion of the brain stem sit in an indented space at the lower rear of the skull. When part of the cerebellum is too large to sit in this area and so begins to extrude below the opening, it is called a Chiari malformation. Since the bony space is smaller than normal, it causes the cerebellum and brain stem to be pushed downward into an area called the foramen magnum and into the upper spinal canal. The resulting pressure on the cerebellum and brain stem may affect functions controlled by these areas and block the flow of cerebrospinal fluid—the clear liquid that surrounds and cushions the brain and spinal cord. This can have serious repercussions in the way the brain operates and the symptoms a patient experiences.
The symptoms most often associated with a Chiari malformation are headache, neck pain, upper extremity numbness, and paresthesias (the feeling of pins and needles). Because the cerebellum controls balance in the brain, unsteadiness and problems with balance are also extremely common. This may extend to similar symptoms like problems with motor skills, coordination, weakness, and dizziness. Those suffering from CM may experience other symptoms commonly associated with problems with brain such as difficulty swallowing, speech issues, problems with vision, and abnormal breathing. Of course these symtoms can vary in degree and from person to person. As mentioned earlier in this article, some patients never experience any symptoms at all. Some dont notice any problems until adulthood. While still others don’t have issues until trauma onsets it. But what about the questions of trauma actualyl causing the Chiari malformation itself?
In recent years, increased research about the causes of Chiari malformations has produced some interesting results. Initially, Chiari malformation was thought to be an exclusively congenital issue that was caused by structural defects in the brain and spinal cord during fetal development. However, recent research has revealed that Chiari malformations can also be related to trauma, especially whiplash.
Several studies have suggested that a previously undetected Chiari malformation can be symptomatically awakened as a result of trauma caused during a motor vehicle crash. While these studies determined that head or neck trauma is capable of “triggering” symptoms relating to CM, in a 2010 study, Michael D. Freeman and number of other experts set out to determine the answer to an even more intriguing question: Could car crash trauma actually be the initiating cause of a Chiari malformation?
The answer is that it’s definitely possible.
Established research has already concluded that Chiari malformation can be acquired later in life (i.e. non-congenital). In a procedure known as lumbar shunting, cerebrospinal fluid (CSF) levels are reduced in order to ease intracranial pressure in patients with neurological disorders. In some cases, reduced CSF levels can allow the brain to drop in the skull to the point that the cerebellum pushes through the foramen magnum, in effect causing a Chiari malformation. This occurs because the flotation level of the brain is dependent on the amount of CSF within the dural covering of the spine and brain. There is clinical evidence showing that dural leaks causing reduced CSF levels are in fact associated with whiplash trauma. This is possible because the damage caused during the whiplash acts like a lumbar shunting, reducing the levels of CSF. The whiplash trauma then causes a dural leak that results in Chiari malformation.
Regardless of whether or not crash trauma triggers pre-existing asymptomatic Chiari malformation or actually causes it, research indicates that symptoms of CM are substantially more prevalent in whiplash-injured patients. The important takeaway from this is that if you suffer head or neck trauma in an accident, especially whiplash, you may develop symptoms and other issues that are unexpected, like a Chiari malformation. In a whiplash mechanism accident, the head moves violently forward then backwards. This is known as an acceleration-deceleration mechanism injury. During such an episode the cerebellar tonsils can pass through the opening at the bottom of the skull (known as the foramen magnum) and pass into the upper part of the neck. In a seminal study published in the Journal of Brain Surgery by Professor Michael Freeman and Dr. Ezriel Kornel, a correlation between acceleration-deceleration injuries and symptomatic Chiari was found after reviewing 1200 cervical MRI results. The study illustrates that a pre-existing congenital Chiari often becomes symptomatic following a motor vehicle collision. [To view the study, click here].
Injuries resulting from automobile accidents, particularly brain and spine injuries can be extremely complicated. If you’re dealing with a brain or neck injury after an auto accident it’s important to hire a personal injury firm that has extensive experience representing clients with serious or complicated injuries.
Dolman Law Group has been retained on a number of Chiari malformation cases, including several referred by other law firms. Insurance carriers often rely on outdated science depicting such injuries to be congenital and will assert that trauma played no role in the pathology. However, we focus only on the symptoms and the lack of symptoms related to Chiari pre-dating an accident. In other cases we focus on an exacerbation or aggravation of a pre-exiting injury wherein it can be illustrated that the symptoms were dramatically altered as a result of a traumatic episode. If the accident caused the symptoms or inflamed them, there is still liability.
In any event, Chiari cases are rarely resolved in pre-suit. A claimant is generally left, with only one potential recourse; which is filing a lawsuit. In our experience, Chiari cases are heavily laden with expert testimony. Therefore, we often retain a radiologist, neurosurgeon, and epidemiologist to illustrate the significance of this type of injury and to show that our client most likely would not have presented with such symptoms had there been no traumatic event. Symptomatic Chiari is a very serious condition that often will not resolve itself without surgical intervention. This often means a patient enduring a craniotomy. A craniotomy is an extremely invasive procedure with a number of associated risks. Due to the long term prognosis of individuals with symptomatic Chiari, we must account for the need for potential future surgical intervention.
If you have concerns about anything related to Chiari or whiplash, or want to discuss a different type of injury case, contact us at 727-451-6900 or by emailing us through our contact page.
1. A case-control study of cerebellar tonsillar ectopia (Chiari) and head/neck trauma (whiplash) . Freeman MD, Rosa S, Harshfield D, Smith F, Bennett R, Centeno CJ, Kornel E, Nystrom A, Heffez D, Kohles SS. Brain Inj. 2010;24(7-8):988-94.