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Cauda equina syndrome refers to a very specific constellation
of symptoms that result from damage to the
cauda equina, which refers to the portion of the nervous
system below the conus medullaris and consists of peripheral
nerves, both motor and sensory, within the spinal
canal and thecal sac. Damage in this region causes a variety
of symptoms, including sciatica; low-back pain; saddleand perianal hypesthesia or analgesia; decreased rectal
tone; absent bulbocavernosus, patellar, and achilles reflexes;
bowel and bladder dysfunction; and variable amounts
of lower-extremity weakness. The causative agent may be
extremely variable and includes lumbar disc herniations,
arachnoiditis, hemorrhage, trauma, and neoplasms. In this
manuscript we review CES in the setting of tumors.First,
we look at the tumor types that are common to this region.
Second, we review the relative incidence of metastatic
tumors and the presentation of patients harboring these
lesions as reported in the literature. Last, we examine outcomes
following surgical and nonsurgical management of
CES caused by neoplastic compression.
Patients with CES caused by a neoplasm often have a
relativelylong, nonspecific disease course. A long history
of back pain and paresthesias as well as occasional urinary
difficulties is very common.10 The patients with primary
tumors are usually young and otherwise healthy, circumstances
that often lead to a considerable delay between the
onset of symptoms and final diagnosis. Patients with metastatic
tumors are older and usually have a history ofcancer.
It is imperative that the condition of patients with a
history of malignancy and new-onset back pain or without
neurological deficit be taken seriously and that the appropriate
imaging studies are obtained. In patients with no
medical history of malignancy but in whom there is
abnormal weight loss, hematuria, hemoptysis, melanotic
stools, and so forth, the possible presence of ametastatic
lesion should be suspected. Most investigations may begin
with AP and lateral plain spine radiography studies. Findings
that should prompt further investigation include pedicle
or other bone erosion, abnormal calcifications, and
new or worsening scoliosis in the setting of back pain. Patients
demonstrating weakness or bowel and/or bladder
dysfunction should undergo MR imaging studieswith and
without Gd enhancement of the appropriate spinal levels,
as dictated by results of the clinical examination. Some
patients may benefit from additional information gained
through CT scanning. In addition to allowing superior
assessment of bone integrity at the offending and adjacent
levels, CT scanning allows one to differentiate between
cauda equina compression from a soft-tissuemass and
that from the bone elements, a distinction that may play
a critical role in planning surgical rather than nonsurgical
treatment.
PRIMARY TUMORS
Myxopapillary Ependymoma
In considering the various common tumor types that
may cause CES, it is helpful to divide this spinal region
into its various parts. First, there are tumors that arise from
the conus medullaris or the terminalfilum. The most common
primary spinal cord tumor in this region (83%) is the
myxopapillary ependymoma. This subclass of ependymoma
has a particularly high affinity for the terminal filum
and is believed to arise from its ependymal glia. These
tumors tend to occur in young adults with a mean age of
36.4 years at presentation.28,31,35 There is a 2.2:1 male/female
ratio. These tumors tend tobe very slow growing,
and patients often present with a rather long history of
Neurosurg Focus 16 (6):e3, 2004, Click here to return to Table of Contents
Cauda equina syndrome caused by primary and metastatic
neoplasms
CARLOS A. BAGLEY, M.D., AND ZIYA L. GOKASLAN, M.D.
Department of Neurosurgery, The Johns Hopkins Hospital, Baltimore, Maryland
Cauda equina syndrome (CES) is defined as the...