Chiari Malformation Treatment – Do You Need Surgery?

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Chiari malformation treatment 2

I often see patients after surgical Chiari malformation treatment. Many actually have craniocervical instability causing their problems, but mistakenly get Chiari surgery and don’t do well. In fact, I just spoke to one of these patients this week on a Telemedicine consult. I tried to explain to her that this is a procedure with significant collateral damage, so I thought it was time for a blog on the topic.

What Is Chiari Malformation?

Chiari malformation occurs when the brain pushes down through the hole in the base of the skull called the foramen magnum. This can cause pressure on the back of the brain (cerebellum) and/or the brain stem. This can lead to a host of symptoms:

  • Neck pain
  • Balance problems, dizziness, or vomiting
  • Muscle weakness or numbness
  • Difficulty swallowing or speaking.
  • Ringing or buzzing in the ears (tinnitus)

The biggest concern is that these symptoms overlap with many other problems. For example, patients with upper neck facet joint injuries get neck pain, balance issues, and other symptoms. Patients who have craniocervical instability (CCI) often have all of the above symptoms. Hence, having an MRI suggestive of a Chiari malformation and these symptoms does NOT mean the next step is invasive surgery.

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Types of Chiari Malformation

chiari 0

Where the rubber meets the Chiari road is which type of malformation is present. The least severe is actually not listed in the above pictures because it’s more controversial, which is often called Chiari 0 or cerebellar ectopia. Few physicians would argue that if you have a portion of your brain that has herniated downwards than you may have a very real need for Chiari malformation treatment through surgical decompression (Chiari 1 or 2 as shown above). However, all too often these days, patients get operated on for Chiari 0 without a frank lower brain herniation, which is the focus of this blog.

Chiari 0 or CTE (Cerebellar Ectopia)

First, Chiari 0, or Cerebellar Tonsillar Ectopia (CTE), is when the back of the brain (cerebellum) isn’t really herniating down through the bottom hole in the skull. Instead, it’s “on the line” of pushing down and out of the skull or has done so just slightly. All of this is much less severe than Chiari 1, which means that surgery for Chiari 0 is very controversial. For example, we don’t have a huge body of research that shows that this MRI finding is associated with symptoms (2).

My colleagues and I performed a research study many years ago which looked at how many cerebellar ectopia or Chiari 0 patients could be found on upright MRI imaging after car crashes (1). We found that about 1 in 5 patients with chronic pain after a car crash had this issue. The question was whether this was causing their symptoms, or an upper neck injury, as many of these patients also had evidence of CCI. Meaning that the ligaments that held their head on had been injured and that the Chiari 0 was being caused by that ligament injury.

Surgery for Chiari 0

chiari surgery

Chiari malformation treatment often involves surgery. The goal is to remove bone and “decompress” the area of the brain with pressure. That means opening the skin, retracting back the muscles, and then removing the bone shown here in yellow. This is often the back of the skull and the back of the c1 and/or C2 vertebrae (if needed). The skull bone removal procedure is called a posterior fossa decompression.

Complications from this procedures are substantial (3). They include more than 1 in 10 of the patients having a dural leak. This means that the doctor cuts through the covering of the brain and spinal cord (the dura) which is the sac containing cerebrospinal fluid in which the brain floats. The dura is then sewn back up and leaks, often requiring another surgery. Other common complications include 9% who get an infection of the brain (meningitis), infected wounds at 7%, and damaged nerves in 5%. About 3% of the patients die from the surgery.

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What Is the Collateral Damage?

chiari malformation surgery

However, a much bigger deal with this surgery, even beyond the very serious complications that could happen, is the collateral damage. To understand that, we need to review the critical anatomy in this area. In the image shown here, note that the PAOM is a ligament in the back of the neck that helps to keep the skull stable on the neck as you look down. Then note the myriad of muscles in the upper neck at the base of the skull. They’re responsible for maintaining your head stability on your neck. Both this ligament and many of these muscles are destroyed when a posterior fossa decompression surgery is performed. Why is this a big deal?

Permanent Bobblehead

This ligament and these muscles at the back of the upper neck and skull are critical for stabilizing your head on your neck. Think of the head as a bowling ball at the end of a stick (your neck). Without an important piece of duct tape (the PAOM ligament) or the muscles that actively balance the bowling ball on the stick, you can become a permanent bobblehead. Hence, outside of huge fusion surgery to bolt all of this together, there is no way to fix the collateral damage done by this aggressive surgical Chiari malformation treatment.

My Patient

Chiari malformation treatment

This is my patient’s MRI to the left. It shows a Chiari 0 or cerebellar ectopia, meaning that she doesn’t have a Chiari 1 with a good chunk of her lower brain having herniated through the bottom of the skull and into the spinal canal. Instead, the surgeon believed that pressure on the lower part of the brain (the cerebellar tonsils) was causing her symptoms. She therefore, underwent a posterior fossa decompression at great personal risk. This didn’t help any of her symptoms which primarily include balance problems, neck pain, and brain fog. She was then later diagnosed with craniocervical instability (CCI) by a neurosurgeon in Spain who wants to now fuse C0-C2 (the skull to her upper neck bones) and her lower neck to boot. She wisely said no and began to explore other options.

Ultimately, she’s likely a candidate for a much less invasive PICL procedure to help tighten down upper neck ligaments damaged while she was playing volleyball many years ago. However, I had to tell her that since the PAOM ligament and many upper neck muscles are no longer there because of the surgical Chiari malformation treatment she has already had, our less invasive injection procedure may fail. So while I have hopes that I can help her and the PICL procedure is less invasive than the planned fusion, because of the collateral damage from surgery, it could be too late. For information on the PICL procedure to help tighten damaged upper neck ligaments without invasive surgery, see below:

The upshot? I wanted to get this blog out to discourage other CCI patients from persuing surgical Chiari malformation treatment. This is a big surgery with big complications, but more importantly, the collateral damage that the procedure causes can be epically bad, and can limit less invasive treatment options. So please think twice before getting this procedure!



(1) Freeman MD, Rosa S, Harshfield D, Smith F, Bennett R, Centeno CJ, Kornel E, Nystrom A, Heffez D, Kohles SS. A case-control study of cerebellar tonsillar ectopia (Chiari) and head/neck trauma (whiplash). Brain Inj. 2010;24(7-8):988-94. doi: 10.3109/02699052.2010.490512.

(2) Furuya K, Sano K, Segawa H, Ide K, Yoneyama H. Symptomatic tonsillar ectopia. J Neurol Neurosurg Psychiatry. 1998;64(2):221–226. doi:10.1136/jnnp.64.2.221

(3) Dubey A, Sung WS, Shaya M, Patwardhan R, Willis B, Smith D, Nanda A. Complications of posterior cranial fossa surgery–an institutional experience of 500 patients. Surg Neurol. 2009 Oct;72(4):369-75. doi: 10.1016/j.surneu.2009.04.001. Epub 2009 Jul 14.

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Category: Neck/Cervical

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5 thoughts on “Chiari Malformation Treatment – Do You Need Surgery?

  1. Sam

    It is contraindicated to perform suboccipital decompressive craniectomy on a TRAUMA patient without first ruling out CCI (atlanto-occipital and/or atlanto-axial instability) and cord traction (anywhere in the spinal column) through rigorous history taking, clinical examinations and radiological work ups (e.g. dynamic MRI, MRA, CSF imaging, DMX).

    Whereas in trauma patients with acquired CTE and radiological evidence of positional CSF disturbance, certain symptoms to certain degree can be attributed to the brain structures compression / CSF disturbance, however in the presence of CCI and/or cord traction the root cause of the majority of symptoms (along with their frequency and magnitude) can be more accurately attributed to the repetitive stretch injury of sensitive brain structures (e.g. brain stem, cranial nerves, vertebral/carotid arteries) causing transient or permanent neurological deficits.

    In patients with cord traction anywhere in the spinal column for any reason (e.g. CCI, spondylolisthesis, disc protrusion in conjunction with kyphosis, tethered cord), isolated suboccipital decompressive craniectomy would likely result in further stretch injury / descent of the brain structures thereby exacerbating the symptoms.

    1) Henderson FC, Geddes JF, Vaccaro AR, Woodard E, Berry KJ, Benzel EC. Stretch-associated injury in cervical spondylotic myelopathy: new concept and review. Neurosurgery. 2005 May;56(5):1101-13; discussion 1101-13.

    2) Thomas H. Milhorat, Paolo A. Bolognese, Misao Nishikawa, Clair A. Francomano, Nazli B. McDonnell, Chan Roonprapunt, Roger W. Kula. Association of Chiari malformation type I and tethered cord syndrome: preliminary results of sectioning filum terminale. Surg Neurol. 2009 July ; 72(1): 20–35. doi:10.1016/j.surneu.2009.03.008.

    3) Scott Rosa, John W. Baird, David Harshfield, Mahan Chehrenama – Craniocervical Junction Syndrome: Anatomy of the Craniocervical and Atlantoaxial Junctions and the Effect of Misalignment on Cerebrospinal Fluid Flow. DOI: 10.5772/intechopen.72890

  2. Nancy B.

    I just wanted to mention that Chiari is often associated with Ehlers-Danlos Syndrome (usually Hypermobile type) and given that this is a genetic connective tissue disorder, surgeries are often less successful than with people who have normal collagen. EDSers often don’t heal well, hence the need for extra hardware etc.

    Having EDS myself, I have noticed that many doctors don’t know much about the condition and believe it is very rare. It is not. Being a syndrome, it has many other manifestations other than ‘loose joints’, many of which can negatively influence the outcome of surgery and other treatments. Those are too numerous to mention here.

    Not all Chiari is caused by trauma and doctors should be aware of this, especially as there has been slim research on treatments like PICL on patients who already are disadvantaged by genetics.

    1. Chris Centeno, MD Post author

      Nancy, yes, EDS patients don’t respond well to surgery! I haven’t seen any controlled trails of CCI surgery nor decompression on EDS patients, do you have a link to one I may have missed?

  3. Nancy B.

    I’m sorry but I don’t have much to offer to you as results of CCI surgery are mostly anecdotal. Bing ‘tapped into’ the EDS community I can tell you that patients have a lot of trouble even finding surgeons who have experience with EDSers, and that includes finding access to upright MRIs. The American Journal of Medical Genetics March 2017 has devoted the entire issue to all things EDS although discussions about surgery are rather limited. I have not run across much information about using stem cell or PRP EDS treatment, probably because it is not usually covered by insurance.

    As far as decompression goes, as you have mentioned in some of your blogs, some EDSers begin by getting surgery for spinal problems due to instability and end up having large sections of their spine fused due to excess stress put on the vertebra above and below.

    Something to take into consideration is that EDSers often have co-morbidities which can vary considerably from patient to patient and are not necessarily included in EDS diagnostics ‘proper.’ Surgeons should expect the unexpected!

    Some of the more common problems include dysautonomia (POTS, NMH etc.), unusual medication sensitivities and metabolism, mast cell issues and unusual allergies, earlier onset osteoporosis and arthritis, IBS and other gastrointestinal issues, other concurrent autoimmune disorders, dislocations and subluxations, and of course, all manner of chronic pain. Surgeons frequently have to deal with ultra fragile skin which easily tears or rips, trouble suturing and wound dehiscence—not to mention poor and much delayed healing—and EDS does not only affect soft tissue, but can affect bone as well. This is only the short list!

    Connective tissue makes up over 1/3 or the body and can affect nearly every system. There are to date, 14 different kinds of EDS, the three most common are Hypermobile, Classical and Vascular (prone to aneurysms mid sized organ rupture). Unfortunately, the genetic underpinnings of the most common type, Hypermobile, are still unknown.

    I don’t know how helpful this might be, but it is a lecture by a neurosurgeon who has a lot of experience treating Chiari in EDSers;

    Again, good luck and I’m sorry I can’t offer you exactly what you are looking for…

    1. Chris Centeno, MD Post author

      Yep, no high-level research that suggests CCI surgery is effective.

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