Syringomyelia (sear-IN-go-my-EEL-ya) is a chronic disorder involving
the Spinal Cord in which a fluid filled cavity (or cyst) forms within
the Spinal Cord. This cyst, called a Syrinx, expands and elongates
over time, destroying the center of the Spinal Cord. As the nerve
fibers inside the Spinal Cord are damaged, a wide variety of symptoms
can occur, depending upon the size and location of the Syrinx.
There are other terms applied to this condition that are used
interchangeably by physicians. These terms, Syringomyelia,
Hydromyelia or Syrinx, all refer to an internal expansion of a
normally very narrow channel (the Central Canal) which occupies a
center position within the center of the Spinal Cord and which is
not normally dilated.
There are two major types of Syringomyelia. In most cases it is
related to a congenital malformation involving the cerebellum and
brainstem called the Arnold-Chiari Malformation. (Please consult
our website information for Arnold-Chiari Malformation.) This
"malformation" occurs during fetal development and is
characterized by downward displacement of the lower part of the
brain (Cerebellar Tonsils) beneath the Foramen Magnum, into the
upper (superior) portion of the Cervical Spinal Canal. This
displacement blocks the normal flow of Cerebrospinal Fluid (CSF).
If Cerebrospinal Fluid, as a result of the interference with its
normal flow within the Fourth Ventricle of the Brain, is abnormally
directed (under pressure developed in the cyclical beating of the
Brain which is synchronous with beating of the Heart)) into this
Central Canal of the Spinal Cord, it may dilate the Central Canal.
This "hydrocephalus" of the Spinal Cord is the "Syrinx". The
Syrinx may compress the surrounding Spinal Cord resulting in damage
by internal compression which then may interfere with the normal
functioning of the Spinal Cord.
Syringomyelia can also be associated with an abnormal "Curvature of
the Spine", a condition known as "Scoliosis". It is important to
recognize that when scoliosis is initially identified,
neuroimaging tests should be considered since the underlying cause
of the scoliosis may be the presence of the Arnold-Chiari Type I
Not all patients with Arnold-Chiari Malformations will develop a
Syrinx, however. it can also occur as a complication of Spinal
Cord trauma, Meningitis, Spinal Cord Tumor (17% of patients with
a Syrinx will also have a Spinal Cord Tumor), Arachnoiditis or
a Tethered Spinal Cord. In these cases the Syrinx forms in the
section of the Spinal Cord damaged by these conditions. As more
people are surviving Spinal Cord injuries, more cases of
post-traumatic Syringomyelia are being diagnosed. Symptoms may
appear months or even years after the initial injury and are
related to the site and anatomical level of the Spinal Cord that
was subjected to the trauma. Some cases of Syringomyelia are
Familial (Genetically determined) although this is rare.
Symptoms usually begin between the ages of 25 and 40 and may
worsen with straining or any activity that causes Cerebrospinal
Fluid pressure to fluctuate. Some patients, however, may have
long periods of stability.
The symptoms of Syringomyelia are numerous and a person may have
various combinations of different symptoms. Symptoms tend to
develop slowly, although sudden onset may occur with coughing
and straining. Since the Spinal Cord connects the Brain to nerves
in the extremities, this damage results in pain, muscle weakness
and spasticity (stiffness) in the trunk, shoulders, arms, or
legs and/or loss of bowel and bladder control. This spasticity
of the lower extremities causes difficulty walking.
Other associated conditions may include osteoporosis and scoliosis.
The majority of patients suffer, at some point in the progression
of this disorder, from headaches and chronic pain as well as a
loss of the ability to feel extremes of hot or cold, especially
in the hands. Each patient experiences a different combination
of symptoms depending on the anatomical level of the Spinal Cord
that is involved in the Syringomyelia process and the extent
of the Syrinx.
Magnetic Resonance Imaging (MRI) is the leading diagnostic tool and
neuroimaging technique of choice for Syringomyelia and has
significantly increased the number of cases diagnosed in the
beginning stages of this disorder. The study should be done with
and without Gadolinium (the paramagnetic "enhancing substance")
that will help to diagnose the presence (or absence) of a
concomitant Spinal Cord Tumor.
Since the natural history of Syringomyelia in any individual patient
is not immediately apparent, particularly if they are not
symptomatic. A Non-surgical or "conservative" approach may be
recommended for these patients; however, these patients should be
carefully monitored by a neurologist or neurosurgeon with experience
in this disorder. Periodic MRI's and physical evaluations should
be scheduled at the recommendation of this uniquely qualified
The first step after a definitive diagnosis has been made is to
find a Neurosurgeon with considerable experience in the treatment
of Syringomyelia. Often times that Neurosurgical specialist is
highly experienced in the management of Arnold-Chiari Malformation
patients as well. Surgery is the only available treatment for
Syringomyelia since there are no medications, manipulations or
interventions that are available for this disorder. It is
apparent that not all patients will advance to the stage where
surgery is required; it is also true that evaluation of the
condition is often difficult because Syringomyelia patients can
remain stationary for long periods of time, while others progress
On the other hand, once the patient with this disorder becomes
symptomatic or develops progression of neurological deficits,
definitive treatment is required. The objective of any treatment
is to stop the progression of symptoms and hopefully to relieve
the symptoms. While it is acknowledged that there are a variety
of approaches that can be used, our considerable experience has
convinced us that treatment is best accomplished by an operation
that results in the "decompression" of the Brain Stem, Cerebellum
and Spinal Cord, along with the re-establishment of more normal
Cerebrospinal Fluid circulation. A successful "Decompression"
is achieved by surgically removing the bony structures at the
back of the skull that are compressing the Brain Stem and
The operation, which is similar to the one advocated for
Arnold-Chiari Malformation (called a Sub-occipital or Posterior
Fossa Craniectomy) involves the removal of the bone from the
back of the Posterior Fossa, called the "Sub-occipital bone".
The outer covering of the Brain, (a tough leather-like substance
called the Dura Mater) must also be opened and "expanded" by
suturing in place an expansion "dural graft". This combined
procedure results in the establishment of much more room for
the Brain, Brain Stem and the Spinal Cord.
In some cases, depending on the unique anatomy of a particular
patient, the back portion of the upper one or two Cervical
Vertebrae must also be removed. This is done in only in those
patients where it is imperative to successfully relieve any
compression of the Spinal Cord from the downward migration of the
Cerebellar Tonsils as occurs in the Arnold-Chiari Malformation.
The removal of the back portion of the vertebra is called a
"Cervical Laminectomy". All portions of the procedures described
above (Posterior or Sub-occipital Craniectomy, Superior
Cervical Laminectomy and insertion of a Dural Decompression Graft)
are accomplished at the same time, through the same surgical
incision in the back of the head and upper neck.
Our experience with over 200 patients with Arnold-Chiari Malformation
(with over thirty years of follow up in some cases) has given us
some unique insight into the methods to re-establish of
Cerebrospinal Fluid circulation and to diminish the "water hammer"
effect that appears to result in the formation of a Syrinx. We
routinely microsurgically divide the tense arachnoid bands that
have grown to hold the herniated Cerebellar Tonsils to the inside
of the Dura Mater in the Foramen Magnum region and in the upper
Cervical Spinal Canal. Once this is accomplished, we routinely
microsurgically separate the Cerebellar Tonsils, in the midline,
free up these arachnoidal band-like attachments to the upper
Cervical Spinal Cord and then enter the lower to mid-portion
of the Fourth Ventricle. Once this is done, CSF can escape the
previously abnormal and confining environment, thus allowing for
a re-establishment of a reabsorbtion pathway and the redirection
of the CSF pulse wave away from the Central Canal of the Spinal
Cord. This latter maneuver is extremely important, in our opinion
and experience, in the successful treatment of most Syrinx
related problems. While this may not entirely reverse the
Syrinx and/or the symptoms, it usually aborts the inevitable
progression of the Syrinx and frequently results in a flattening
or disappearance of the Syrinx as the normal flow of Cerebrospinal
Fluid is restored.
We strongly oppose the concept of "amputation" or removal of the
Cerebellar Tonsils as a method to decompress the Spinal Cord.
While "amputation" needlessly invades normal Brain substance, it
also creates a greater risk to post-operative haemorrhage as well
as scar formation which then can result in a late failure of the
operation. To date, we have not seen any patient who has needed a
diversionary "shunt" operation to control ventricular size.
An alternative treatment involves the insertion of a tiny (1
millimeter diameter) Silastic tube (a shunt) into the
Syringomyelia cavity. The operation consists of Laminectomy
(removal of the Lamina the roof of the Spinal Column) over
the particular Spinal level corresponding to the Syrinx. A tiny
opening is made in the back of the Spinal Cord in order to
insert the tube into the Syringomyelia cavity. The tube is fixed
in place with a very fine non-absorbable (permanent) suture and
serves to reroute the Cerebrospinal Fluid from within the Spinal
Cord. A successful surgery will, hopefully, stabilize the
condition and perhaps gain a modest improvement in symptoms.
Unfortunately this operation requires opening the Spinal Cord
over a miniscule segment which nevertheless, destroys that tiny
portion of the Spinal Cord where the opening is made. In our
experience, this invariably results in some sensory impairment
and/or dysaesthesia (disagreeable altered sensation) since the
area of the back of the Spinal Cord is a "sensory tract".
Historically, over time, this surgery is not always successful
and multiple surgeries may be necessary.
The "Terminal Ventricle" is a peculiar anatomical structure that
becomes apparent in some patients with Syringomyelia. The Central
Canal of the Spinal Cord may be dilated at the end of the Spinal
Cord. In these patients, it is possible to open into that
"Ventricle" to place a tiny Silastic tube (similar to the one
described above). This results in a "venting" or indirect
decompression of the Syrinx which is connected to the Terminal
Ventricle through the Spinal Cord's Central Canal. This operation
can be accomplished using Minimally Invasive technique through a
Thoraco-lumbar junction Laminectomy. It, as well, requires opening
through "normal" Spinal Cord which means risking some
neurological function. In this case the very end of the Spinal
Cord may not place the patient at much risk. The actual risk
depends on the precise location of this Terminal Ventricle.
It is imperative to realize that early and definitive treatment
is fundamental to the successful management of patients who are
symptomatic from an Arnold-Chiari Malformation particularly those
who harbor a Syrinx as well. The chances for successful
resolution of the myriad of neurological problems that can
accompany this syndrome are lessened the longer that a
symptomatic patient delays definitive treatment. The symptoms
due to Syringomyelia are more difficult to completely resolve. The
success here is inversely proportional to the extent of the
Syrinx, the amount of Spinal Cord substance that has been
destroyed, the extent of functional neurological impairment as
well as the length of time of the neurological disturbance. It
is for these reasons that early treatment is very important.
National Institute of Neurological Disorders and Stroke
(request Publication #94-3780 on Syringomyelia)
National Institutes of Health
Bethesda, MD 20892 USA
Office of Scientific and Health Reports
NIH Neurological Institute
P.O. Box 5801
Bethesda, MD 20824 USA
American Syringomyelia Alliance Project, Inc.
P.O. Box 1586
Longview, TX 75606-1586 USA
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This page last edited on 2/20