| Dr.
Miguel B. Royo Salvador
Neurosurgery and Vertebral Column |
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<< Syringomyelia | |
<< Arnold Chiari I malformation | |||||||||||||
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"Scoliosis, syringomyelia and Arnodl Chiari malformation can be stopped." |
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ARNOLD CHIARI I MALFORMATION
What is Arnold Chiari I malformation?
Arnold Chiari I or Chiari malformation, 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 the like. Since at the time when this classification was made no other associated malformation was seen to explain the Chiari I, other causes were suggested, namely, 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 malformation, 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 upon the 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 and is called filum terminale. It has been known for 50 years that this ligament may cause in some people traction of the spinal cord in much the same way as myelomeningocele does in Chiari II and Chiari III malformations.
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Desde hace
más de 30 años nuestras investigaciones explican
que en la malformación de Chiari I existe una tracción
de la médula espinal por una malformación que no
la detectamos: el filum terminale tenso, causa lo mismo que en
la malformación de Chiari II y III, tira de la médula
espinal hacia el canal vertebral. La médula espinal y la columna vertebral tienen la misma longuitud en el quinto mes de vida embrionaria, de aquí hasta la madurez la columna vertebral llega a crecer un palmo más. Entre la columna vertebral y la médula espinal existe un ligamento que las une llamado filum terminale. Está descrito hace 50 años que éste ligamento en algunas personas puede causar tracción de la médula espinal de igual modo que lo hace el mielomeningocele en las malformaciones de Chairi II y III.
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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.
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Figure 2.- Simplified sagittal section of the skull and the brain, normal on the left, on the right, with the cerebellum protruding downward through the foramen occipitalis as does when there is an Arnold Chiari malformation.
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, tha 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.
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. Thus,
the progression of the disease is stopped when the cause is supressed.
The symptoms of the Chairi I disease are due to the stress suffered by
the brain tissue as it is moved downward and it 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 these caused also improve.
What exactly is the surgical section
of the filum terminale?
The surgical section of the filum terminale is carried out by making a
small incision on the sacrum, at the end of the backbone, so there is
no alteration of the spine mechanics, visualizing the filum terminale
and cutting it by means of microsurgery techniques, all of which is done
in hardly half an hour and the patient is in hospital less than a day.
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.
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 there are important arteries there for the spinal cord and because
spinal cord arteries are centripetal, 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.
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 socalled cerebellar tonsils, into the
foramen occipitalis which connects the skull to the spine, causing the
Arnold Chiari malformation, a disease described 100 years ago and was
of unknown cause up to present.
The surgical section of the filum for Arnold
Chiari malformation 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 because of their little elasticity.
The tethering of the filum terminale, aside from 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.
Does this mean that syringomyelia
can also be treated with the same surgical technique as scoliosis and
Chiari I malformation?
In a similar way to scolisis and Chiari I malformation, 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 there is the ependymal canal, 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 about spine cord strain. The symptoms of
the disease are caused by the cell death 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.
Has this treatment been applied to
patients?
40 patients of the three diseases, that is, scoliosis, Arnold Chiari malformation
and syringomyelia, have been operated; some had all three conditions,
and in some cases, the improvement has been dramatic.
Can you give an examplel?
A forty-eight year old woman had a very pronounced scoliosis; she had
had back pains since the age of fourteen, whatever position she was in,
even lying in bed, when getting up, when rolling constantly, she did not
have a pause for thirty-four years. She was operated seven months ago
and has not had the slightest vertebral pain since (case 14 of publication
4).
One case of syringomyelia: a young man of twenty-five, he had no sense
for temperature on the left side of his body and had a big cyst in the
centre of the spinal cord (case 2 of publications 3 and 4). Six hours
after the operation, the specialist verified the total recovery of the
patient’s sense of touch, the improvement lasting to present, eleven
years later. This patient now works in a warehouse in Galicia, while other
specialists, at the sight of his serious injuries predicted total disability
in two years after diagnosing syringomyelia.
Bibliography
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".
PhD thesis (PDF).