Arnold-Chiari Malformation and Syringomyelia – Medical Marijuana Research Overview

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A Chiari malformation is a structural defect that causes the cerebellum to be positioned incorrectly within the skull that can cause a syringomyelia, or cyst filled with cerebrospinal fluid, to form. Studies have shown marijuana can help curtail the pain, sleeping problems and spasms often associated with the condition.

Overview of Arnold-Chiari Malformation and Syringomyelia

Chiari malformations are structural defects in the cerebellum. Normally, the cerebellum and parts of the brain stem rest at the lower rear of the skull, just above the foramen magnum. In a Chiari malformation, less commonly known as Arnold-Chiari malformation, the cerebellum is positioned below the foramen magnum. Chiari malformation is the leading cause of syringomyelia, which is a syrinx or cyst that accumulates cerebrospinal fluid within the spinal cord and causes the cord to expand.

According to the National Institute of Neurological Disorders and Stroke, primary or congenital Chiari malformations occur during fetal development and may be caused by genetic mutations or a lack of adequate vitamins or nutrients in the maternal diet. The malformations can also be caused later in life, in what’s referred to as a secondary Chiari malformation, if an injury, infection or exposure to harmful substances requires that spinal fluid be drained excessively from the lumbar or thoracic areas of the spine.

Chiari malformations commonly cause headaches, swallowing problems, sleep disturbances, vocal quality changes and balance problems or dizziness. If developed, syringomyelia’s can cause a sensory loss or an exaggerated response to pain, limb weakness and atrophy, muscle spasms, and pain.

Surgery to correct the functional disturbances and prevent the progression of damage to the central nervous system is the only treatment option for a Chiari malformation and syringomyelia.

Findings: Effects of Cannabis on Arnold-Chiari Malformation and Syringomyelia

Cannabis has demonstrated that it can be helpful for managing some of the symptoms associated with Arnold-Chiari malformation and syringomyelia. Cannabis use is prevalent among patients with a chronic illness, and the most frequently reported reasons for use include improvements in pain, sleep and mood (Ware, et al., 2003).

The cannabinoids found in cannabis, tetrahydrocannabinol (THC) and cannabidiol (CBD), are effective at lowering pain levels associated with a wide variety of conditions, including spasticity, headache, migraines, and other acute pain and chronic pain conditions (Jensen, Chen, Furnish & Wallace, 2015) (Baron, 2015).

Cannabis has been long known to help with sleep. One survey study analyzing cannabis’ effect on patients of chronic illnesses found that 75% to 84.2% of respondents reported that cannabis “slightly/much better” improved their sleep. Users are able to fall asleep faster and sleep longer (Tripp, et al., 2014).

There’s also strong evidence that suggests that cannabinoids contained in cannabis reduce muscle tremors and spasticity because of their activation of the cannabinoid receptors, CB1 and CB2, of the endocannabinoid system (Pertwee, 2002). The CB1 and CB2 receptors regulate the excitatory and inhibitory neurotransmitters necessary to curtail spasms (Syed, McKeage & Scott, 2014) (Smith, 2002).

States That Have Approved Medical Marijuana for Arnold-Chiari Malformation and Syringomyelia

Currently, the only state to have approved medical marijuana for the treatment of Arnold-Chiari malformation and syringomyelia is Illinois. However, other states allow medical marijuana to treat some of the symptoms commonly associated with the Arnold-Chiari malformation and syringomyelia.

Several several states have approved medical marijuana specifically to treat “chronic pain,” a symptom commonly associated with Arnold-Chiari malformation and syringomyelia. These states include: Alaska, Arizona, California, Colorado, Delaware, Hawaii, Maine, Maryland, Michigan, Montana, New Mexico, Ohio, Oregon, Pennsylvania, Rhode Island and Vermont. The states of Nevada, New Hampshire, North Dakota, Montana, Ohio and Vermont allow medical marijuana to treat “severe pain.” The states of Arkansas, Minnesota, Ohio, Pennsylvania and Washington have approved cannabis for the treatment of “intractable pain.”

Sixteen states have approved medical marijuana for the treatment of spasms. These states include: Arizona, Arkansas, California, Colorado, Delaware, Florida, Hawaii, Maryland, Michigan, Minnesota, Montana, Nevada, New Hampshire, Oregon, Rhode Island and Washington.

A number of other states will consider allowing medical marijuana to be used for the treatment of Arnold-Chiari malformation and syringomyelia with recommendation by a physician. These states include: California (any debilitating illness where the medical use of marijuana has been recommended by a physician), Connecticut (other medical conditions may be approved by the Department of Consumer Protection), Massachusetts (other conditions as determined in writing by a qualifying patient’s physician), Nevada (other conditions subject to approval), Oregon (other conditions subject to approval), Rhode Island (other conditions subject to approval), and Washington (any “terminal or debilitating condition”).

In Washington D.C., any condition can be approved for medical marijuana as long as a DC-licensed physician recommends the treatment.

Recent Studies on Cannabis’ Effect on Arnold-Chiari Malformation and Syringomyelia
  • One survey study found that for most, using cannabis improves mood, pain, muscle spasms, and sleep.
    A survey of cannabis (marijuana) use and self-reported benefit in men with chronic prostatitis/chronic pelvic pain syndrome.


Baron, E.P. (2015, June). Comprehensive Review of Medicinal Marijuana, Cannabinoids, and Therapeutic Implications in Medicine and Headache: What a Long Strange Trip It’s Been… Headache, 55(6), 885-916.

Chiari malformation and syringomyelia. (n.d.). Mayo Clinic. Retrieved from

Chiari Malformation Fact Sheet. (2015, August 27). National Institute of Neurological Disorders and Stroke. Retrieved from

Jensen, B., Chen, J., Furnish, T., and Wallace, M. (2015, October). Medical Marijuana and Chronic Pain: a Review of Basic Science and Clinical Evidence. Current Pain and Headache Reports, 19(10), 524.

Pertwee, R.G. (2002, August). Cannabinoids and multiple sclerosis. Pharmacology & Therapeutics, 95(2), 165-74.

Smith, P.F., (2002, June). Cannabinoids in the treatment of pain and spasticity in multiple sclerosis. Current Opinion in Investigational Drugs, 3(6), 859-64.

Syed, Y.Y., McKeage, K., and Scott, L.J. (2014, April). Delta-9-tetrahydrocannabinol-cannabidiol (Sativex): a review of its use in patients with moderate to severe spasticity due to multiple sclerosis. Drugs, 74(5), 563-78.

Tripp, D.A., Nickel, J.C., Katz, L., Krsmanovic, A., Ware, M.A., Santor, D. (2014, November). A survey of cannabis (marijuana) use and self-reported benefit in men with chronic prostatitis/chronic pelvic pain syndrome. Canadian Urological Association Journal, 8(11-12). Retrieved from

Ware, M.A., Doyle, C.R., Woods, R., Lynch, M.E., and Clark, A.J. (2003, March). Cannabis use for chronic non-cancer pain: results of a prospective survey. Pain, 102(1-2).

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