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Mining the Past to Help Patients with Chiari Malformations

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Ever realize you have something that could help another person? Maybe you happen to have the exact tool she needs for a project, or a pair of great snow boots that, come winter, are too small for your son but the perfect size for a friend’s.

It’s a great feeling.

Three of our doctors recently had a similar experience, and they took action by publishing a paper in the March 2016 issue of the journal Child’s Nervous System. Pediatric neurosurgeons Dr. Richard Anderson and Dr. Neil Feldstein, along with resident Dr. Benjamin Kennedy*, used their records of more than 250 patients surgically treated for Chiari I Malformation to help kids with Chiari everywhere.

Chiari I Malformation (CMI) is a condition that tends to arise during childhood or young adulthood. In CMI, part of the base of the brain is squeezed down, out of the skull and into the spinal canal. The brain, brainstem and spinal cord may be mildly or severely compressed. Sometimes CMI causes no symptoms and may need no treatment, and sometimes it leads to symptoms like headache, neck pain, overactive reflexes and trouble swallowing.

CMI may also cause an additional problem. As the brain is pushed down out of the base of the skull, it may block the flow of cerebrospinal fluid, the liquid that bathes the brain and spinal cord. Without its usual flow route, the cerebrospinal fluid sometimes forms a cavity within the spinal cord. This cavity in the spinal cord is known as a syrinx (Greek: tube, pipe, channel).

Both CMI and any resulting syrinxes can squeeze and injure the delicate tissues of the nervous system. Nearly all pediatric neurosurgeons agree that CMI and syrinxes that cause symptoms should be treated with surgery.

Surgical treatment aims to provide more room for the base of the brain, brainstem and spinal cord. The most basic treatment approach is to remove a piece of bone at the base of the skull. This procedure often provides the brain with enough space to fit comfortably. If successful, this procedure also restores a normal flow of cerebrospinal fluid, and the syrinx will resolve.

In some cases, however, the basic procedure is unlikely to provide enough relief. Then neurosurgeons may do a slightly more extensive procedure that involves helping the dura, the brain’s protective covering, fit a little less tightly. They make an opening in the dura over the base of the brain, which relieves pressure there. Then they patch the opening with a graft of artificial dura, effectively increasing the size of the covering.

Unfortunately, choosing the right treatment is not straightforward. Doctors differ on questions such as: Which patients are best treated with observation alone? When should the more extensive procedure be performed? What treatment option is best when a syrinx is present but causes no symptoms?

But there is one thing that almost every neurosurgeon agrees on: It’s important to know whether there is a syrinx.

A syrinx indicates that the flow of cerebrospinal fluid is blocked, which is not desirable. The majority of pediatric neurosurgeons agree that a patient whose CMI has caused a syrinx, whether or not he or she has symptoms, should be considered for surgery.

Pediatric neurosurgeons often perform the more extensive type of surgery if a patient has a syrinx. And following surgery, a syrinx that doesn’t disappear indicates that another operation may be necessary. So doctors use the presence of a syrinx to help decide when to treat, what type of treatment to offer and whether the treatment worked.

But here’s the thing: Sometimes doctors don’t always check the entire spinal cord for syrinxes. A lot of times, they only check the neck. This is because taking an MRI of a child’s entire spinal cord sometimes requires sedation or anesthesia, which doctors generally want to avoid. Unfortunately, no one knows just exactly how common CMI syrinxes are below the neck.

That is, no one knew, until now.

At Columbia, neurosurgeons have long believed that in order to make the best treatment plan, it is crucial to know whether a child with CMI also has a syrinx. Therefore, the standard practice here is to take MRIs of a child’s entire spinal cord when he or she is first diagnosed.

Drs. Feldstein and Anderson and their team had a decade and a half of MRIs and other records about patients’ entire spinal cords. The information had already served its original purpose of providing outstanding care to their patients. But the team saw that the information could also help all kids with Chiari, and their neurosurgeons, find the best treatment.

So the team looked back over the records of more than 250 CMI patients under the age of 21 treated at Columbia University Medical Center/Morgan Stanley Children’s Hospital of NewYork-Presbyterian between 1998 and 2013. All of the patients had received an MRI of the entire spinal cord, in accordance with the doctors’ standard practice.

The authors wanted to know just how many of those patients had a syrinx only below the neck. Then they hoped to find out if the patients with a lower syrinx had anything else in common—symptoms, MRI findings, age or sex, anything—that could help doctors everywhere predict which kids might be more likely to have one of these syrinxes lower in the spinal cord.

The team found that 4.5 percent of their patients had syrinxes only below the neck, in the thoracic spine—syrinxes that were only found because the standard practice was to take an MRI of the entire spinal cord. While that’s a relatively low number of patients overall, the accurate information had a huge impact on those patients’ treatment. (Remember that doctors use a syrinx to help decide what kind of treatment to use, whether treatment has been successful and even whether to treat at all.)

But, the team found, the patients with the lower syrinxes in the thoracic spine had nothing else in common. They could not be distinguished from patients with syrinxes in the neck—or no syrinxes at all—by any particular signs or symptoms, the size or shape of their malformations, their age at diagnosis or any other factor. There was no way to predict who might have a syrinx in the spinal cord below the neck. Such a syrinx could only be found by looking for it.

Therefore, Drs. Anderson, Feldstein and Kennedy recommend in their paper that when a child is first diagnosed with CMI he or she receive an MRI of the entire spinal cord. In almost 5 percent of patients, they say, this will allow doctors to find a syrinx that would have otherwise been missed. For that 5 percent of kids, the information is likely to have a significant effect on their doctors’ ability to choose the best treatment.

Pediatric neurosurgeons will continue to use their own judgment about MRIs; not all of them will follow this paper’s recommendation. But for the first time, all doctors will be able to make a decision informed by data showing exactly how many kids with CMI are likely to have syrinxes lower in the spinal cord.

With this information and their recommendation, Drs. Anderson, Feldstein and Kennedy have provided a tool that other neurosurgeons can use in their own work. And they provided it from records gathered in the course of offering great care to their own patients. That’s a good feeling that starts here at home and can spread to doctors, kids and families everywhere.

*Title and full list of authors: Isolated Thoracic Syrinx in Children with Chiari I Malformation.
Kennedy BC, Kelly KM, Anderson RC, Feldstein NA.

Learn more about Dr. Richard Anderson on his his bio page here.

Learn more about Dr. Neil Feldstein on his bio page here.

Image credit: © [cherylholt]/pixabay

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