A Chiari malformation also commonly referred to as cerebellar ectopia or Arnold Chiari malformation. is a head injury long thought to be only congenital in nature. However, several recent studies have shown a correlation between a traumatic episode (i.e., auto accident) and symptomatic chiari. In other words, a Chiari malformation can be asymptomatic for an indefinite period of time. In fact, most individuals with a Chiari malformation have no idea.
A Chiari I malformation is a structural defect in the cerebellum, the part of the brain that controls balance. Normally, the cerebellum and parts of the brain stem sit in an indented space at the lower rear of the skull, above the foramen magnum. When part of the cerebellum is located below the foramen magnum, it is called a Chiari malformation or tonsillar ectopia. Chiari malformations may develop when the bony space is smaller than normal, causing the cerebellum and brain stem to be pushed downward into 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 – to and from the brain.
The symptoms most often associated with Chiari I malformations include occipital headache, neck pain, upper extremity numbness, paresthesias (“pins and needles”) and weakness. In some cases there can also be lower extremity weakness and signs of cerebellar dysfunction.
In recent years, increased research about the causes of Chiari I 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 that occur 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 I 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 Chiari I malformations, in a 2010 study, Michael D. Freeman and number of other experts set out to determine an even more intriguing question: could motor vehicle crash trauma actually be the sole cause of a Chiari I malformation? The answer is that it’s definitely possible.
Established research has already concluded that Chiari malformation can be acquired (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. Accordingly, it is quite possible that whiplash trauma could cause a dural leak that results in Chiari I malformation.
Regardless of whether or not crash trauma triggers pre-existing asymptomatic Chiari I malformation or actually causes it, research indicates that symptoms of Chiari I malformations 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 resulting from a Chiari I 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 written by Professor Michael Freeman and Dr. Ezriel Kornel, a correlation between acceleration/deceleration injuries and symptomatic chiari was found after reviewing 1200 cervical MRI films. 1 The study illustrates that a pre-existing congenital Chiari often becomes symptomatic following a motor vehicle collision. Disruption of the CSF results in symptoms including dizziness and disorientation.
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.
We have 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 thereof of symptomatology 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.
In any event, Chiari cases are rarely if ever 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 and we often retain a Radiologist, Neurosurgeon and Epidemiologist to illustrate the significance of this injury and the likelihood of our client presenting with such symptoms absent a traumatic event. Symptomatic Chiari is a very serious condition that often will not resolve absent surgical intervention, which generally consists of 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.
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.