Chiari Malformation Type I | Arnold Chiari Syndrome

An Overview of Chiari Malformation Type I
& Arnold Chiari Syndrome

There are four types of Chiari Syndrome. The only one that would present beyond birth is type I. Type II is also known as Arnold Chiari Syndrome. Type II is associated with myelomeningeocele and these patients are recognized at birth. Myelomeningeocele patients present at birth with their lower spinal cord out-pouched at the lumbar spine (meningeocele). Types III and IV are severe and not survivable.

Chiari type I was thought to occur in 1 of every 1000 births but with the more ubiquitous use of cervical MRI scans; this disorder appears to be more common. Generally, females outnumber males three to one. Many patients with the Chiari malformation are totally asymptomatic and the disorder is only discovered by imaging studies related to other cervical conditions.

Chiari Malformation

This is really a congenital disorder of the formation of the posterior fossa of the skull. The occipital bone forms the deep “cup” that contains the cerebellum. In Chiari syndrome, the bony cavity that forms is too small to contain this part of the brain and subsequently causes compression of the cerebellum. The parts of the cerebellum that can “squirt out of the way” are the cerebellar tonsils, structures that are almond shaped and found on the sides of the cerebellum. These tonsils lie against the brain stem and are forced into the only exit available, the foramen magnum.

The cerebellar tonsils are pushed into the foramen magnum and crowd out the spinal cord. This crowding can create spinal cord compression, brain stem compression, obstruction of the flow of cerebral spinal fluid (CSF) down the spinal canal and a “water hammer” type effect that can cause an enlargement or syringomyelia of the central canal.

Basilar Invagination

Basilar invagination is a condition associated with occipital bone malformation where the base of the skull “melts” over the upper cervical spine. The top of C2 (the odontoid) then protrudes into the foramen magnum, crowds the brainstem and cerebellum causing similar symptoms as the Chiari malformation.

Compression of the Lower Brain Stem (Pons and Medulla)

When the cerebellar tonsils are pushed into the foramen magnum, the lower brain stem and cranial nerve nuclei can be compressed. This includes the Hypoglossal nerve (CN XII which is a pure motor nerve). The Hypoglossal nerve innervates the tongue and compression affects swallowing and speech. Facial pain or numbness can occur from compression of the Trigeminal nerve (CN V). Problems with breathing can occur from compression of the Medulla and problems with sleep can occur due to compression of the Pons. Sleep apnea can be a result.

(Click to Enlarge) Chiari I – note the upper arrow points to the cerebellar tonsil which is elongated and jammed into the foramen magnum. Lower arrow points to syrinx

(Click to Enlarge) Syringomyelia is the large white circle in the middle of the black cord

Are you suffering from symptoms of Chiari Syndrome?

Would you like to consult with Dr. Corenman about your condition?
You can set up a long distance consultation to discuss your
current X-rays and/or MRIs for a clinical case review.

REQUEST A SECOND OPINION

(Please keep reading below for more information on this condition.)

General Chiari Malformation Symptoms

The Chiari malformation without syringomyelia can cause neck pain and occipital (base of the skull) headaches with coughing, exertion or sneezing. This is due to the increased intrathecal pressure associated with the ValSalva maneuver (holding the breath and contracting the diaphragm-associated with the above actions). The sneeze increases the congestion at the CSF bottleneck at the foramen magnum, which increases base of skull pain. Weakness, numbness, balance problems and hoarseness can also occur. Possible eventual loss of bowel and bladder control can occur eventually in some cases.

Cerebrospinal Fluid Circulation Blockage/Syringomyelia

One of the major problems with Chiari syndrome is the blockage of cerebrospinal fluid (CSF) at the foramen magnum. The choroid plexus inside the lateral ventricles of the brain produces cerebrospinal fluid. CSF then passes though the third ventricle, the aqueduct of Sylvius and then the forth ventricle. CSF then passes out of the skull through the foramen magnum and into the subdural space of the spinal cord. The CSF finally travels down the spine to the sacrum where it is reabsorbed by the arachnoid granules in the sacrum.

Chiari syndrome causes the cerebellar tonsils to block the flow of CSF through the foramen magnum like the cork on a Champaign bottle. Since the pressure increases in the brain, this pulsatile fluid has to go somewhere. One of the pathways still open is the very thin but still patent central canal of the spinal cord.

The persistent production of CSF and the CSF pressure acts as a “water hammer” and can cause dilation of this canal. This dilation is called a syrinx and the cyst that forms can damage the central spinal tracts of the cord. It is estimated that 2/3 of patients with Chiari syndrome will eventually develop a syringomyelia.

Syringomyelia slowly causes a variety of symptoms. Noted are a loss of skin sensitivity to hot and cold, a loss of skin sensation in a “shawl” or “cape” distribution, numbness of the hands and feet, muscle weakness and spasticity.

Physical Examination

Physical Examination findings will depend upon the brain and spine structures affected due to the compression. Difficulty with speaking and breathing can be related to brain stem compression. Upper spinal cord compression will cause long tract signs (hyperreflexia, Hoffman’s sign, clonus and Babinski’s reflex). Cerebellum compression will cause ataxia, dysmetria and incoordination, The CSF block will cause symptoms of upper neck pain and headaches with coughing or sneezing.

Non-Surgical Treatment of Chiari Malformation

As noted before, many patients have no symptoms and this malformation is found as an incidental finding. If there are mild symptoms only and there are no cranial cysts or syringomyelia, medications can be used such as non-steroidal anti-inflammatories. Impact and contact sports probably should be avoided.

Surgical Treatment of Chiari Syndrome

Surgery is the treatment for severe Chiari malformation and MRI findings. The problem as noted earlier is crowding of the cerebellum with a too tight foramen magnum. The surgery is a posterior fossa decompression surgery. The back rim of the foramen magnum is removed with a small part of the back of the skull. The dura typically will be constricted here and will need to be widened. This is performed by incising (opening) the dura, letting it gap and then placing a patch over the open hole (similar to widening the waistline on a pair of pants). Occasionally, the back part of the ring of C1 will also need to be removed (C1 laminectomy) to make more room for the cord and cerebellar tonsils.

For additional resources on Chiari malformation type I, or to discuss Arnold Chiari Syndrome with a spine specialist and neck doctor, please contact the office ofDr. Donald Corenman.

Related Content

Donald Corenman, MD, DC

Average rating:

81 reviews

Eric S

Sep 26, 2021

by Eric S on Donald Corenman, MD, DC

Successful pars repair at 46 years old

Back in November of 2018 (at 46 years old) I came from Vancouver BC to have a pars repair done with Dr. Donald Corenman at the Steadman Clinic in Vail Colorado. I'm finally posting this review nearly three years later in late 2021. The reason I waited so long was I wanted to know the final result before I posted my review. Unfortunately in that time Dr. Corenman has retired. Nevertheless, I want to post this review of Dr. Corenman and his staff at the Steadman Clinic in their excellent treatment of my L5 pars interarticularis.

I fractured my pars at age 42 back in 2014 when rolling on the gym floor, and was denied treatment by the Canadian healthcare system, probably due to my age. First my GP told me there was no surgical option for a pars defect, which was quite incorrect! I tried to live with it, but the symptoms worsened (periodic random spine slippage and weeks of resultant pain after just bending over to tie my shoe, so I eventually learned to mostly squat and hardly bend). When I finally consulted with Canadian spine surgeons, I was told they believed my pars defect had been congenital (since birth). This was absurd, considering I had done extreme martial arts (including jiu jitsu) for years prior, as well as 5 years of reinforcing steel full time in my 20s, probably the hardest job on the back you can find. No pars defect like mine would possibly have allowed this--ergo it was impossible that I had had the defect since birth. I did however have an asymptomatic congenital spina bifida occulta that made me more susceptible to a pars fracture. In 2014 in one instant, I went from having the strongest back people I knew said they'd ever seen, to being unable to safely bend over and tie my shoe without a non-negligible risk of my spine slipping randomly (which would lead to weeks of pain after each occurrence). This was due to the unilateral L5 pars defect, otherwise known as spondylolysis. It was when lying in pain on the floor 4 years later after maybe the 6th spine slippage event post injury, that I had had enough, and resolved to have surgery. If Canada's "universal health care" said no, I would make lemonade from lemons, and find the very best surgeon in the world at pars repairs. That was Dr. Donald Corenman. Dr. Corenman back in 2018 ran a website https://neckandback.com/ that dedicated many pages to the science of every aspect of pars repairs, from eligibility (good discs on MRI), to best surgical techniques (minimal open compared to minimally invasive), best imaging to use (i.e., O-Arm with Stealth imaging vs. older fluoroscopy), the ideal amount of BMP to use and why not use too much or too little, and much more, all to do with pars repairs, pages upon pages of his site just on the pars, with scientific references and his own extensive expert opinion. As a health research statistician, I was very impressed with this. It was in stark contrast to the websites of other spine surgeons which barely gave the pars a word or two, focusing almost exclusively on fusions. I had found the best surgeon in the world for pars repairs, and so after Dr. Corenman personally screened my MRI to ensure my discs were healthy, I booked the surgery.

Being 46 years old at the time of surgery in 2018, with a 4-year-old pars fracture from 2014 combined with a congenital SBO meant my pars fragment was somewhat atrophied, but it was "very solid", said Dr. Corenman in the operative report. Nevertheless, it was challenging with two things to fix, the pars and SBO, and OR time was around 4 hours. Recovery over the following months was guided by a very clear "Spine binder" from the Steadman Clinic with strict rules of "no BLT" (no bending, lifting or twisting), and illustrated physiotherapy guidelines. They even warned patients to avoid fish oil supplements, which could excessively dampen inflammation and hence slow bone healing. They answered many questions I had during months of recovery, with responses coming from the very supportive Lori Fugate (then director of Dr. Corenman's practice), and Ehrich Bean (then physician's assistant at the practice), as well as a couple calls with Dr. Corenman himself after two of the CT scans. Ehrich Bean offered great advice for taking the spine binder conservatively due to the nature of pars repairs vs. fusions. The final post-op CT scan I had was a couple weeks ago at 34 months post-op, and Dr. Corenman had retired, but I got a very positive and informative call from Eric Strauch (current PA at the Steadman Clinic under Dr. Corenman's replacement there, and who had also worked with Dr. Corenman previously). The staff at the Steadman Clinic were extremely supportive all the way through the process. I should mention, the local Canadian spine surgeon did offer me very good post-operative support including antibiotics as needed to deal with a mild surface incision-site infection early on, booking numerous x-rays when I felt something was amiss, as well as booking all four of my post-op CT scans. I am very grateful for that support also.

My final result shows plenty of solid bone across the pars and a healed SBO, with my vertebral body now a solid bone ring instead of being broken at two places as it was pre-op. Does my spine hold up in the real world? You bet! I have recently dug and moved several yards of dirt and sand and gravel by myself (shovel and wheelbarrow!) to fix our water main, pulled roots from the yard, moved several "portable" (these are HUGE) air conditioners up several flights of stairs my myself, and lifted weights. I now run 2 miles (3.2 KM) several times weekly with a hard 100 meter dash in the middle. I bend deeply before each run I go on, with no spine slippage. My spine feels amazing. I can bend over to do exercise, or real word tasks, with no risk of spine slippage.

My sincere thanks to God, Dr. Donald Corenman, Lori Fugate, Ehrich Bean, Eric Strauch, and the Steadman Clinic, as well as the Canadian spine surgeon who offered me excellent post-operative care back in Canada. You have all given me a new lease on life.

Sincerely,
Eric S

Robert S

May 11, 2021

by Robert S on Donald Corenman, MD, DC

Back Fusion Surgery

I had my entire lumbar spine fused in November of 2018. I had scoliosis , with pinched nerves that were so painful I could hardly walk - and standing for more than a few minutes was impossible. Even sitting was painful.
The fusion surgery produced immediate relief! And the recovery was much easier than I expected.
To this day I can do all the activities I love from hiking, to standing in a stream fly fishing to riding my bike long distances - or just walking down the street with my wife.
Kudos to Dr. Corenman and his staff, (including the two Erics) for taking such good care of me!

Leslie R

Jul 9, 2020

by Leslie R on Donald Corenman, MD, DC

TLIF

I had my TLIF surgery on 6/24/2020 by Dr. Corenman, I can not say enough good things about the Dr or his staff. I was always treated with respect and explained everything throughly, that made it easy for everyone to understand. I highly recommend Dr. Corenman and the Steadman Clinic.

Chiari Malformation Type I (Arnold Chiari Syndrome)

An Overview of Chiari Malformation Type I
& Arnold Chiari Syndrome

Chiari Malformation

Basilar Invagination

Compression of the Lower Brain Stem (Pons and Medulla)

Are you suffering from symptoms of Chiari Syndrome?

General Chiari Malformation Symptoms

Cerebrospinal Fluid Circulation Blockage/Syringomyelia

Physical Examination

Non-Surgical Treatment of Chiari Malformation

Surgical Treatment of Chiari Syndrome

Related Content

About the Author: Donald Corenman, MD, DC

Submit your review
First Name, Last Initial:
Email:
Review Title:
Rating:	1 2 3 4 5
Review:

Check this box to confirm you are human.
Submit Cancel

Chiari Malformation Type I (Arnold Chiari Syndrome)

An Overview of Chiari Malformation Type I & Arnold Chiari Syndrome

Chiari Malformation

Basilar Invagination

Compression of the Lower Brain Stem (Pons and Medulla)

Are you suffering from symptoms of Chiari Syndrome?

General Chiari Malformation Symptoms

Cerebrospinal Fluid Circulation Blockage/Syringomyelia

Physical Examination

Non-Surgical Treatment of Chiari Malformation

Surgical Treatment of Chiari Syndrome

Related Content

About the Author: Donald Corenman, MD, DC

An Overview of Chiari Malformation Type I
& Arnold Chiari Syndrome