Arnold Chiari I Syndrome

What is Arnold Chiari I Syndrome?

What is Arnold Chiari I Syndrome?

Arnold Chiari I or Chiari Syndrome, described some 100 years ago, refers in general to a condition where there is a downward displacement of the lower portion of the brain: the cerebellar tonsils and the lower part of the cerebellum protrude through the foramen occipitalis into the spinal canal. In malformations Chiari II and III there is a downward displacement of the spinal cord because it is fixed by other spinal malformations such as the myelomeningocele or others. At the time when this classification was made no other associated malformation was seen to explain the Chiari I, other causes were suggested, such as, problems with the circulation of cerebrospinal fluid or small size of the the posterior fossa where the cerebellum is located. For more than 30 years, our research explains that there is a downward movement of the spinal cord in Chiari I Syndrome, due to a malformation not detected: tight filum terminale is responsible for the same symptoms of Chiari II and Chiari III malformations; it pulls the spinal cord into the vertebral canal. The spinal cord and the spine have both the same length up until fifth month of embryonic life, from this point to adulthood, the spine will grow up to twenty more centimeters. There is a ligament between the vertebral column and the spinal cord which links them named filum terminale. It has been known for 50 years that this ligament may cause in some people a traction of the spinal cord in much the same way as myelomeningocele does in Chiari II and Chiari III Syndromes.

For over 30 years our research explains that in the Chiari I Syndrome there is a tensile strength of the spinal cord by a malformation that did not find: the Phylum terminale tense, because as in the Chiari Syndrome II and III, strip of the spinal cord into the vertebral canal.

The spinal cord and spinal column have the same length in the fifth month of embryonic life, from now until the maturity spine reaches grow an inch more. Among the backbone and spinal cord there is a ligament that connects called filum terminale. Described 50 years ago that some people in this ligament can cause traction of the spinal cord the same way as did the myelomeningocele in malformations of Chairi II and III.

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What is the function of the filum terminale?

The filum terminale is the result of the union between the membranes that cover the spinal cord adhered to the bottom of the vertebral canal. From the fifth week of the embryo, these membranes join together with the end of the atrophied spinal cord which would have been the human primitive tail. In adults, the filum terminale does not develop any function.

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Treatments for this disease:

- Craniectomy: (By means of decompression of the foramen magnum or occipital hole)
1. Eliminate sudden death.
2. Some patients improve.
2. 0,5 to 3% of mortality, greater percentage of sudden death.
3. Aggressive, mutilating and with consequences.
4. Improves slightly.
5. Neurological deficit: Depending on the location of the lesion: Hemiparesia (paralysis of hemibody) from 0,5 to 2,1%. Visual field alteration from 0,2 to 1,4%. Speech alteration from 0,4 to 1%. Sensitive deficit from 0,3% to 1%. Instability (walking difficulty) from 10 to 30%.
6. Post-surgical intra-cerebral hemorrhage, from the surgical bed, epidural or intraparenchymal, causing neurological deficit or worsening of a pre- existent deficit from 0,1 to 5%.
7. Heart attack- Edema, variable depending on the process and the situation until 5%.
8. Profound or cerebral superficial infection from 0,1 to 6,8% with cerebral abscess formation, aseptic-septic meningitis.
9. Hemodynamic alteration from the manipulation of cerebral stem injuries.
10. Gaseous embolism (seated postural patients).
11. Cerebrospinal fluid leakage from 3-14% (Fistula of CSF).
12. Post- surgical hydrocephalus.
13. Pneumocephalus.
14. Tetraparesis (Loss in strength in the 4 limbs) incidentally from the surgical position.

- Section of the filum terminale (SFT)
1. Eliminates the cause of Arnold Chiari I Syndrome, Syringomyelia, Scoliosis, Platybasia, basilar impression, odontoid retrocession, kingking of the brainstem and possibly nocturnal enuresis.
2. 0 % of mortality. Without important consequences.
3. With a minimal invasive technique, 45 minutes of surgical time.
Short period of hospitalized hours. Short post surgery recovery.
4. Improves the symptoms and stops the evolution of ACHI, SM and SCO of less than 40 degrees curvature.
5. Improves the blood flow in the whole nervous system (NS).
1. Minimal incision in the sacrum.
2. As the spasticity improves, there can be a loss of strength.
3. As the sensitivity improves, it can increase pain or feel atypical sensations.
4. An increase of brain irrigation increases brain activity and the nature´s personality.

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What use is this explanation to the Chiari I patients?

To begin with, the mere section of that ligament called filum terminale stops the strain to which the spinal cord is subject. The lower part of the brain stops moving downward into the upper part of the vertebral canal.


Fig 2.- Simplified sagittal section of the skull and the brain being normal on the left. But on the right, with the cerebellum protruding downward through the foramen occipitalis as does when there is an Arnold Chiari Syndrome.

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Does the section of the filum terminale make the brain move back to its original place?

If the human brain had the plasticity and memory of a spring or if it was made of rubber, the cerebellar tonsils and the cerebellum would move back to their original position. However, the brain has formed under a strong traction power. When it is freed from this strain, its recovering depends on its degree of plasticity, which in time depends on the age of the patient, the genes, the time and intensity of the strain.

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Then, what is the use of cutting the ligament?

The first thing achieved with the section of the filum terminale is the elimination of the main strain that makes the disease progress. Therefore, the progression of the disease is stopped when the cause is supressed. The symptoms of the Chiari I disease are due to the stress suffered by the brain tissue as it is moved downward and protrudes into the foramen occipitalis. When the filum terminale is cut, in spite of the fact that the magnetic resonance imaging does not show any apparent change in the position of the protruding part of the brain, the strain of the spinal cord has disappeared and the opression inside the foramen occipitalis has decreased. Congestion and the lack of blood in the affected area improve and, therefore, the symptoms also improve.

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What is the surgical sectioning of the filum terminale?

The surgical sectioning of the filum terminale consists in making a small opening at the sacrum bone, at the end of the spine, without involving any inconveniences that could alter the mechanics of the spine. The Filum terminale ligament is exposed and sectioned with microsurgical techniques, all in just half an hour and it has the added bonus of requiring hospitalization of less than a day.

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Does tethering of the spinal cord have any effects on the brain?

The strain of the filum terminale, besides forcing the spine to bend, in order to prevent the strain of the spinal cord, it also pulls downward the lower part of the brain, the so called cerebellar tonsils, into the foramen occipitalis which connects the skull to the spine, causing the Arnold Chiari Syndrome, a disease described 100 years ago and was of unknown cause up to present.

The surgical section of the filum for Arnold Chiari Syndrome makes the downward strain disappear for the cerebellar tonsils, it stops them from suffering because they do not opress themselves into the foramen occipitalis anymore. The operation improves many of the symptoms of the disease and the cerebellar tonsils do not move upwards because they are deformed and have little elasticity.

The tethering of the filum terminale, besides causing a downward movement of the cerebellum and the death of the central part of the spinal cord, generates a flexion-producing stimulus on the spine that seeks preventing the strain of the spinal cord and causes a spinal deformity called Scoliosis.

The section of the filum terminale supresses the flexion-producing stimulus and stops Scoliosis

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What are the consecuences of cutting this ligament?

The filum terminale is the result of the empty cover of the spine cord at the lower back or lumbosacral region. The covering that separates the spinal cord from the spine at the sacrum and lower back, dura mater, arachnoid mater and pia mater, do not contain spine cord anymore and fold as a fibrous cord which forms the filum terminale; this portion of the spinal cord can be compared to a sock we are wearing and we pull taking it half way off our foot: the half that does not contain our foot could be cut with no risk to our foot. In much the same way, the filum terminale can be cut at any point with no harm.

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Does the spinal cord suffer because of the tethering?

Research and tests with animals have proven that a mild tethering of the spinal cord makes neurons stop functioning due to insufficient blood flow. In humans, intense tethering decreases blood flow inside the spinal cord, because here there are important arteries found and because these arteries are centripetal, meaning they go from the outside to the inside, especially at the cervical region, since there is the limit to the downward movement. The lack of blood flow causes the necrosis or death of part of the spinal cord tissue, and then it attracts interstitial fluid from within the spine and forms a cyst in the centre of the spinal cord called syringomyelic cavity, syrinx or Syringomyelia, a disease described 500 years ago, of unknown cause up to present. 

arnold chiari

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Does this mean that syringomyelia can also be treated with the same surgical technique as Scoliosis and Chiari I Syndrome?

In a similar way to Scoliosis and Chiari I Syndrome, in the case of syringomyelia the section of the filum terminale stops the disease. The cyst resulting from the necrosis remains the same, but it may disappear when the space surrounding the spinal cord opens spontaneously or does so towards its centre where the ependymal canal is found, which connects the centre of the spinal cord to the brain cavities. This does not mean that the disease is cured, it only means that the cyst has emptied; the disease persists since it is all about spine cord strain. The symptoms of the disease are caused by the death of cells and the tumor-like effect of the cyst. The section of the filum has three beneficial effects: it stops the death of cells caused by spine cord strain, it helps recover the non functioning but alive neurons, and it diminishes the tumor-like effect of the cyst because it relaxes the spinal cord.

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Has this treatment been applied to patients?

Patients have been operated suffering Arnold Chiari I Syndrome with or without idiopathic Syrigomyelia and/or idiopathic Scoliosis. The progression of the disease has been stopped during its evolution and patients have had recoveries, in some cases spectacular ones.

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Can you give an example?

You can find patients cases in the testimonials section: Arnold Chiari I Syndrome.

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Images: Before and after the Sectioning of the Filum terminale

- Case No. 16453
                                      2008                                                                                         2010
Arnold Chiari 2008  Arnold Chiari 2010

- Case No. 14183
                                      2011                                                                                        2012              
Arnold Chiari 2011  Arnold Chiari 2012

- Case No. 15704
                                      2010                                                                                         2011
Arnold Chiari 2010  Arnold Chiari 2011

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Pathologies and the definitions related to the Filum Disease.

Fore more information on the concept of the Filum Disease please see:
 "Involved Diseases"

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1. Siringomielia, escoliosis y malformación de Arnold-Chiari idiopáticas, etiología común (PDF).
2. Platibasia, impresión basilar, retroceso odontoideo y kinking del tronco cerebral, etiología común con la siringomielia, escoliosis y malformación de Arnold-Chiari idiopáticas (PDF).
3. Nuevo tratamiento quirúrgico para la siringomielia, la escoliosis, la malformación de Arnold-Chiari, el kinking del tronco cerebral, el retroceso odontoideo, la impresión basilar y la platibasia idiopáticas (PDF).
4. "Results of the section of the filum terminale in 20 patients with syringomyelia, scoliosis and Chiari malformation".Acta Neurochir (Wien). 2005 Feb 24 (PDF).
5. "Aportación a la etiología de la siringomielia", Tesis doctoral (PDF).

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