Ependymomas arise from the cells that line the
Ventricles (Cerebrospinal Fluid spaces within the Brain) and
the Central Canal of the Spinal Cord. Seventy (70%) percent of
Ependymomas that affect the Brain, occur in children. In the
Spinal Cord, however, about 96% occur in adults. This type
Brain tumors tends to occur in the Posterior Cranial
Fossa (the lower back portion of the Brain). About 10% of the Brain
tumors will spread to the Spinal Cord through the Cerebrospinal
Fluid.
There are a number of varieties of Ependymoma recognized by
the
World Health Organization.
- The Papillary Ependymoma (the most common)
occurs in the Brain and Spinal Cord.
- The Myxopapillary Ependymoma occurs only at
the bottom of the Spinal Cord (a region called the
"Filum Terminale".)
- The Subependymoma is a common finding at autopsy and
a rarely require surgical intervention.
- Finally there is the Anaplastic Ependymoma, a
more aggressive tumor.
These are tumors that arise from Ependymal Cells within the
substance of the Spinal Cord and are the most common
Intramedullary Tumor in adults. These tumors, which
affect men and women equally, occur throughout life,
but are more frequently seen in the middle adult
years.
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FIGURE 1A (Left): MRI Scan (Gadolinium Enhanced-Sagittal View)
of a C2-C4 Intramedullary Ependymoma (Arrow)
in a 33 year old Male.
Figure 1B (Right): MRI Scan (Transaxial View at C2-3-Same Patient)
There is a thin "rim" of Spinal Cord
surrounding the tumor (Curved Arrow.)
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The usual treatment for this Spinal Cord Tumor is surgical
removal. Modern
Minimally Invasive Microsurgical Techniques
have been effective in advancing current treatment plans.
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Figure 2A (Left): Intra-operative x-ray (Same Patient as
Figures 1A&B) for the precise positioning of the
Minimally Invasive Medtronic "X-tube"
retractor in preparation for a Bilateral C2-C4 Laminectomy
-Unilateral Approach.
Figure 2B (Right): Operative Photo (Same patient) of the
Minimally Invasive Retractor in position
through a 26 millimeter right paramedian incision.
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Figure 3A (Left): Post-operative CT Scan (Same Patient)
Double-ended Arrow indicates the Right sided
Laminectomy at C3. The Broad Arrows correspond to the Horizontal
Arrows in Figure 3B (Right). This
is a 3-D CT reconstruction of the Cervical Spine in this patient.
The Curved Arrows indicate the upper & lower limits of the
Laminectomy.
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Figure 4 (Above): Operative Photo-Same Patient as Figures 1 & 2)
A Minimally Invasive C2-C4 Bilateral
Laminectomy (Unilateral approach) allowed sufficient exposure.
Here, the Dura Mater (Straight Arrows) has been opened. The
surface anatomy of the Spinal Cord is distorted by the pressure
exerted from within the Spinal Cord by the large Intramedullary
Ependymoma.
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Figure 5: Operative Photo (High Magnification-Same Patient.)
The entire tumor has been removed permitting
an unusual view of the interior of the Spinal Cord. In order to
accomplish this tumor resection, a short incision was made
through the Posterior surface of the Spinal Cord recognizing
that this may well result in a permanent, although limited,
sensory deficit. Note the intact Anterior Spinal Artery visible
in the extreme depth of the tumor resection cavity.
Compare this view with the Pre-operative MRI Scan (Figures 1A & B)
and the Post-operative CT Scan images in Figures 3A & 3B to
understand the Minimally Invasive surgical approach.
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Figure 6 (Below): MRI Scan (C3 Level-Same Patient as Figures 1-7)
at 5 weeks post-operative.
The Spinal Cord (Curved Arrow) appears
to have re-expanded after the Tumor was completely removed. (Compare
this to Figure 1B.) The Minimally Invasive Laminectomy
Unilateral surgical avenue (Double-ended Arrow) is visible
here and can be compared to Figures 3A & 3B.
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Figure 7 (Right): Photo of patient at his 5-week post-operative office visit.
He is fully ambulatory with normal control
of bowel & bladder function. He still has significant weakness
in his Right Deltoid muscle (resulting in difficulty raising
his arm above his head) and in the Right hand. These weaknesses
have continued to improve fairly quickly.
Immediately post-operatively, he was quadriparetic (weak in
all 4 extremities) with the Right side worse than the Left.
He made rapid progress and was transferred to a Regional
Rehabilitation Facility where he continued to improve to full
ambulation and capable of self care.
These patients are followed, on a long-term basis, with MRI
Scan. Absent evidence of recurrence of tumor, further treatment
(Chemotherapy &/or Radiation) is not required.
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Radiation treatment (preferably in the form of Stereotactic Radiosurgery)
may be required in patients where there is evidence of persistent
or recurrent tumor.
Chemotherapy may be necessary for some patients.
These tumors differ from other Ependymomas by their
location within the Filum Terminale, a neurologically
non-functioning structure at the lower-most end of the
Spinal Cord.
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Figure 8A (Left): MRI Scan (Sagittal View)
L3 level Filum Terminale Ependymoma is a
solid mass filling the Spinal Canal (Arrow.)
Figure 8B (Right): MRI Scan (Transaxial View)
shows the Tumor infiltrating the Nerve
Roots (Curved Arrow).
A Minimally Invasive Surgical resection was
followed by Radiation & Chemotherapy.
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The role of surgery for Filum Terminale Ependymomas
depends on the size of the tumor and its relationship
to the surrounding roots of the Cauda Equina. We strongly favor
Minimally Invasive Microsurgical
with Gross Total Resection when possible. Complete
surgical resection can be accomplished with small and moderate-sized tumors
that remain well circumscribed within the fibrous coverings of the
Filum Terminale and are separable from the Nerve Roots of the
Cauda Equina. Large tumors can present significant problems for
surgical resection. These tumors have been present for many
years and present a risk for spread through the
Cerebrospinal Fluid (CSF). Filum Terminale Ependymomas that are large
and adherent to many Nerve Roots can make total removal difficult
to impossible without considerable damage to the Nerve Roots to which
they are densely adherent.
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Figure 9A (Left): MRI Scan (Sagittal View) 7B (Right): Axial
View-same patient as Figures 1A & B)
2 years post-op resection of
infiltrating Filum Terminale Ependymoma
Note how the Nerve Roots have remained "clumped" together
(Arrows)
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While many can be safely and completely resected, those that cannot or
should not be totally removed can be treated with post-operative
Radiation Therapy and Chemotherapy.
Even in cases where the Tumor can be removed totally, a recurrence
rate of at least 20% can be anticipated.
Biologically aggressive tumors, which are more common
in younger patients, can recur early after removal. Radiation
therapy is an important adjunct for these patients as well as
those in whom a significant amount of tumor is left behind during the
operation.
Neuro-oncologic chemotherapy
is an additional option available in some centers.
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Figure 10: MRI Scan Series (Sagittal View)
An L1 & L2 Lumbar Level Filum Terminale
Ependymoma (Arrows) in a 19 year old male.
This tumor was completely removed using a Minimally Invasive
approach. No further treatment was required.
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Figure 11: MRI Scan (Transaxial View-Same patient as Figure 3.)
The tumor (Curved Arrow) appears to occupy
the entire Spinal Canal.
At surgery, the Spinal Nerve Roots (Arrows point to the "dark"
round objects) are EXTERNAL to the Tumor and compressed against
the inside walls posteriorly of the Dural covering of the Spinal
Canal.
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We invite the reader to explore our section
Spinal Cord Tumor Case Studies
for further examples of spinal Cord Ependymoma cases.
From among our patients with Spinal Cord Tumors,
we have selected several to present in this special section
in order to illustrate the application of Minimally Invasive
Techniques as well as some of the characteristics, differences
and challenges encountered with these clinical problems.
An example of a complete resection of a Filum Terminale Ependymoma is
contrasted with another case in order to demonstrate the issue of dense
adherence to Nerve Roots, which limits the reasonable possibility of
complete resectability.
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This page last edited on 2/19
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