Chiari Bridges

Tag: Heritable Disorders of Connective Tissue

  • The Important Questions to Ask Your Neurosurgeon [Revised]

    The Important Questions to Ask Your Neurosurgeon [Revised]

    Most Chiarians go to see a surgeon with an expectation of them being knowledgeable in their field. However, while they might be a neurosurgeon, their knowledge of Chiari and its comorbid/pathological conditions might not rank high in their practice. Make the most of your initial appointment by interviewing them and what they really know about Chiari Malformations. Be cautious of inflated success rates. Chiari decompression in general offers a just over a 50% success rate (which means it has a nearly 50% failure rate). Surgeons that claim a 100% (or near 100% success rate) are usually not basing their success on how their patients feel afterward, it is based on if they were successful with the aspects of the surgery:
             Removal of the occipital bone ✓
              Opening the dura and adding the patch/graft ✓
              Laminectomy ✓
              Cauterization/resection of cerebellar tonsils ✓

    WE DESERVE BETTER THAN THAT!

    HERE IS A LIST OF CHIARI QUESTIONS WE RECOMMEND ASKING AT YOUR FIRST NEUROSURGERY APPOINTMENT:

    General Questions:

    • How do you define a Chiari Malformation?
    • What do you believe causes a Chiari malformation?
      • Are all Chiari malformations from a small posterior fossa?
      • Do I have a small posterior fossa? If yes, how big is it? If size is unknown, was my posterior fossa measured? If not, why not? How did you come to the conclusion that I have a small posterior fossa?
      • How common do you believe Acquired Chiari malformations to be?
    • Do you always recommend decompression surgery for all of your patients with herniated cerebellar tonsils? Why/why not?
    • In an average month, how many Chiari decompressions do you perform? How many tethered cord releases? How many craniocervical fusions? What percentage of your practice is spent treating patients with these connective tissue related conditions?
    • Looking at my brain scan, is any part of my “brainstem” herniated (below the posterior fossa)? If so, does that make me a Chiari 1.5?

    Intracranial Hypotension (low pressure) Questions:
    *Article to help you understand CSF Leaks & Intracranial Hypotension prior to your appointment.
    If you have SYMPTOMS OF LOW INTRACRANIAL PRESSURE and/or suspect a cerebrospinal fluid leak, we recommend asking the following questions:

    • S.E.E.P.S.
      • Looking at my brain scan, do you see any Subdural fluid collections?
      • Looking at my brain scan, do you see an Enhancement of pachymeninges?
      • Looking at my brain scan, do you see an Engorgement of my venous structures? Should we do an MRV to make sure?
      • Looking at my brain scan, does my Pituitary appear to be enlarged?
      • Looking at my brain scan, does my brain appear to be Sagging?
    • Looking at my corpus callosum:
      • Does there appear to be a depression?
      • Is there an inferior pointing of the splenium?

    If he/she answers affirmatively to any of the above S.E.E.P.S. questions, ask: 

    • What should be done to find/repair a potential leak?
    • Are you aware that it is common for CSF Leaks to not show up on MRI?
    • Are you willing to do a CT Myelogram and/or a digital subtraction myelogram, if I develop symptoms of a leak and none can be found on MRI?
    • Are you aware that it can often take multiple epidural blood patches to try and seal a leak, and sometimes when a blood patch fails to work, a surgical dural repair might be necessary?

    Intracranial Hypertension (high pressure) Questions:
    *Article to help you understand Intracranial Hypertension prior to your appointment.
    If you have SYMPTOMS OF HIGH INTRACRANIAL PRESSURE, we recommend asking the following questions:

    • Looking at my brain scan, do I have cerebrospinal fluid in my sella turcica (Empty Sella Syndrome)?
    • Looking at my brain scan, do you see any evidence of my optic nerves are swollen (papilledema)?
      • If so, should I be referred to a neuro-ophthalmologist?
    • Looking at my brain scan, do my lateral ventricles appear small or flattened?
      • If so, do I need to have my pressures checked?
        • If yes, are you aware of the risks of developing a CSF Leak from a lumbar puncture?
      • What are the symptoms of a CSF Leak, should one develop?
        • What is your plan of action if I should develop these leak symptoms?
        • Are you aware that it is common for CSF Leaks to not show up on MRI?
        • Are you willing to do a CT Myelogram if I develop symptoms of a leak, and none can be found on MRI?
      • Should a leak be found, are you aware that it can often take multiple epidural blood patches to try and seal a leak?

    Tethered Cord Questions: 
    *Article to help you understand Tethered Cord: Sorry, Coming Soon.
    If you have SYMPTOMS OF TETHERED CORD, we recommend asking the following questions:

    • Looking at my brain/cervical scan, does my brainstem appear to be elongated?
    • Looking at my cervical scan, does my spinal cord appear to be stretched?
    • Looking at my lumbar scan, does my conus reach my mid/low L2?
    • Looking at my thoracic and lumbar scan, does my spinal cord appear to be pulling to the back, or one particular side?
      • If so, should we do a prone MRI to see if it has actually adhered to that side?
    • Looking at my lumbar scan, do I appear to have fatty tissue inside the epidermis?
      • If the answer to any of these questions is affirmative, do you suspect that I have a tethered spinal cord?
      • If so, should we plan for a Tethered Cord Release before or soon after decompression surgery, so the likelihood of a failed decompression is reduced?
      • If I have urological issues, can I get a referral for urodynamic testing to rule out any other potential causes of my urological issues?

    Craniocervical Instability (CCI) & Atlantoaxial Instability (AAI):
    *Article to help you understand CCI & AAI prior to your appointment.
    If you have SYMPTOMS OF CRANIOCERVICAL INSTABILITY or SYMPTOMS OF ATLANTOAXIAL INSTABILITY, we recommend asking the following questions:

    • Looking at my brain/cervical scans, what are the measurements of my clivoaxial angle and Grabb-Oakes?
    • Do these measurements meet the diagnostic criteria for Craniocervical Instability?
    • Looking at my flexion and extension imaging, how many millimeters of translation are there between flexion and extension?
    • Does Chamberlain’s Line cross my odontoid? If so, does it cross at a level that would indicate Basilar Invagination?
    • Looking at my rotational imaging, what is the percentage of uncovering of the right and left articular facets on rotation?
    • Do the percentages from my rotational imaging meet the diagnosis criteria for Atlantoaxial Instability?

    IF A DIAGNOSIS CRITERIA IS MET IN ANY OF THE ABOVE, WE STRONGLY RECOMMEND THAT YOU WAIT ON DECOMPRESSION AND PURSUE THE TREATMENT OF SAID CONDITION(S) AND THAT OF EHLERS-DANLOS SYNDROME, AS EACH OF THESE CONDITIONS CAN BE PATHOLOGICAL TO AN ACQUIRED CHIARI AND EACH IS A STRONG INDICATOR THAT A CONNECTIVE TISSUE PROBLEM EXISTS. 

    *The questions in this article will periodically change as we are able to expand our recommended questions.

    *Original version released September 2018, revised 2023.

  • The Chiari Malformation Ehlers-Danlos Connection

    The Chiari Malformation Ehlers-Danlos Connection

    CHIARI (KEE-AR-EE) MALFORMATIONS ARE FAR FROM RARE, THEY ARE JUST RARELY UNDERSTOOD, EVEN BY MOST MEDICAL PROFESSIONALS. A CHIARI MALFORMATION EXISTS WHEN THE LOWEST PART OF THE HIND BRAIN (THE CEREBELLAR TONSILS) PROLAPSES INTO THE HOLE AT THE BOTTOM OF THE SKULL (FORAMEN MAGNUM), ENTERS THE SPINAL CANAL AND OBSTRUCTS THE FLOW OF CEREBROSPINAL FLUID (CSF), PUTS PRESSURE ON THE BRAIN STEM AND SPINE, AND MAY RESULT IN VARYING DEGREES OF NERVE COMPRESSION.

    PREVALENCE OF CHIARI: Once thought to occur in 1 in 1000 people, it is now believed to be much more frequent of an occurrence. A 2016 pediatric study found it to occur in 1 in 100 children[1]. Since Chiari Malformation Type 1, the most common type, tends to become symptomatic during late teens and early adulthood, it is likely to be much more common when adults are factored in.

    THE CONNECTION: Chiari malformations were originally believed to be caused by a posterior fossa hypoplasia (small area inside the back of the skull) and doctors speculated that lack of maternal prenatal care or drug abuse caused the deformity. However, as studies continue, they are finding that many with this hind brain herniation have connective tissue disorders, such as Ehlers-Danlos Syndromes. Ehlers-Danlos Syndromes involve a mutation in one of the collagen genes. Collagen is a protein that is often described as a “cellular glue” that helps hold the body together. When that glue fails to hold, everything seems to go awry; specifically, as related to Acquired Chiari Malformations: organs tend to prolapse, and bones begin to shift as joint laxity increases (including the bones/vertebrae at the craniocervical junction). They are finding that these acquired Chiari malformations are far more common than originally thought. There are many pathological co-factors that can cause or attribute to the formation of a Chiari Malformation, and most can be linked to these Heritable Disorders of Connective Tissues (HDCTs), including a posterior fossa hypoplasia. In one large study, they found those with a Chiari malformation and no associated co-factors, with only slightly over 52% having a small Posterior Cranial Fossa (PCF). When other co-factors were present, the number of Chiarians found with a small PCF plummeted and therefore it is should be considered acquired until proven otherwise.[2]

    DIAGNOSES: A decade ago, it took 10-20 years from the onset of symptoms to be diagnosed and now it takes an average of 1-2 years, because medical professionals are slowly beginning to look for it. Magnetic Resonance Imaging (MRI) remains the best tool for diagnosis. Some medical professionals believe that a tonsillar herniation of less than 5mm is simply a tonsillar ectopia and only diagnose a Chiari malformation when the descent is > 5mm. However, the 5mm requirement is controversial and many doctors now base their diagnoses not solely on measurements, but rather on symptomology and a combination of other factors (including Cine MRI, a patient’s symptoms, and other relevant factors). Due to the prevalence of connective tissue issues, gravity often proves to be a significant factor and should be taken into account by use of an upright MRI whenever possible.[3] EDS should be diagnosed by a geneticist before surgery is considered.

    TREATMENT OPTIONS: There is no cure for a Chiari malformation, but there are treatment options. When symptoms are minimal and not life-altering, pain management is usually offered. However, it is important to know that while medications may ease some symptoms, Chiari symptoms tend to be progressive. Decompression surgery is the only treatment available to attempt to halt the progression of the damage being done to your Central Nervous System (CNS). The most common reason that decompression surgeries fail, is undiagnosed co-morbid conditions, especially those that can be etiological/pathological co-factors. More than one surgery might be necessary to successfully treat a Chiari malformation and any/all co-morbid conditions and there is a correlation between early surgical intervention and positive surgical outcomes[4].

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    References:

    1 Eltorai, Ibrahim M. “Rare Diseases and Syndromes of the Spinal Cord” Cham: Springer International Publishing: Imprint: Springer, 2016. Page 43, 15.2, <www.springer.com/us/book/9783319451466>.

    2 Milhorat, Thomas H., et al. “Mechanisms of Cerebellar Tonsil Herniation in Patients with Chiari Malformations as Guide to Clinical Management.” Acta Neurochirurgica, Springer Vienna, July 2010, <www.ncbi.nlm.nih.gov/pmc/articles/PMC2887504>.

    3 Henderson, Fraser C., et al. “Neurological and Spinal Manifestations of the Ehlers–Danlos Syndromes.” American Journal of Medical Genetics Part C: Seminars in Medical Genetics, 21 Feb. 2017, <www.onlinelibrary.wiley.com/doi/10.1002/ajmg.c.31549/full>.

    4 Siasios, John, et al. “Surgical Management of Patients with Chiari I Malformation” International Journal of Pediatrics, Article ID 640127, Hindawi, 2012, <https://www.hindawi.com/journals/ijpedi/2012/640127>.