metastases are almost always diagnosed after the diagnosis of the
primary cancer. 25% of spinal tumors in children are metastatic
deposits. 80% of those with bone metastases will have a spinal
involvement. They are more frequent in the elderly (6th and 7th
decade). There is a slight male preponderance.
sources for spinal metastatic disease include the following: Lung
(31%), Breast (24%), GI (9%), Prostate (8%),
Lymphoma (6%), Melanoma (4%), Unknown (2%), Kidney
(1%), Others including multiple myeloma (13%). Time relation
between primary and spinal metastases vary according to the site and
nature of the primary.
from primary tumors is mainly by the arterial route via nutrient
artery. Retrograde spread through the Batson plexus during Valsalva
maneuver has been postulated. Direct invasion through the
intervertebral foramina also can occur.
70% of symptomatic lesions are found in the thoracic spinal region,
20% in the lumbar region, and 10% in the cervical spine. Over 50% of
patients with spinal metastasis have multiple level involvement.
About 10-38% of patients have multiple noncontiguous segment
involvement. Most of the lesions are localized at the anterior
portion of the vertebral body (60%). In 30% of cases the lesion
infiltrates the pedicle or lamina. A small percentage of patients
have disease in both posterior and anterior parts of the spine.
and intramedullary metastases are not as common as those of the
vertebral body and the epidural space. Isolated epidural involvement
accounts for less than 10% of cases; it is particularly common in
lymphoma and renal cell carcinoma. Epidural
metastasis is the most ominous complication of bone metastasis to
the vertebral spine and is a medical emergency. The tumor enters
the-epidural space by contiguous spread from adjacent vertebral
metastasis in the vast majority of cases. The remaining cases arise
from the direct invasion of retroperitoneal tumor or tumor located
in the posterior thorax through adjacent intervertebral foramina or,
rarely, from bloodborne seeding of the epidural space.
mass effect, an epidural mass can cause cord distortion, resulting
in demyelination or axonal destruction. Vascular compromise produces
venous congestion and vasogenic edema of the spinal cord, resulting
in venous infarction and hemorrhage. The relative importance of
vascular factors as opposed to purely mechanical ones has been a
subject of controversy for many years. The tempo of development of
spinal compression is, perhaps, impossible to generalize. Once
neurological symptoms become manifest, the condition is a
pain at night in a patient with cancer is always an ominous symptom.
The majority of the patients present with radicular pain. The
pain is usually midline, but patients whose tumor involves nerve
roots have sharp or shooting pain in a radicular distribution.
Untreated, the pain slowly intensifies with a mean duration of 7
weeks from the onset of pain to the onset of neurological deficits
due to spinal cord compression. Half of
these patients have sensory and motor dysfunction and over 50% have
bowel and bladder dysfunction.
5-10% of patients with cancer present with cord compression as their
initial symptom. Among those who present with cord compression, 50%
are nonambulatory at diagnosis and 15% are paraplegic.
x-ray is used to show erosion of the pedicles or the
More than 70 percent of patients with spinal cord
compression have an abnormal plain radiograph in the region
of pain (compression fracture, plastic, or lyric
Owl eye erosion of the pedicles in the anteroposterior (AP)
view of lumbar spine is characteristic of metastatic disease
and is observed in 90% of symptomatic patients. Osteoblastic
or osteosclerotic changes are common in prostate cancer and
Hodgkin disease; occasionally, they also are seen in breast
cancer and lymphoma.
scan is useful in determining the integrity of the
vertebral column, especially when surgery is anticipated. CT
if MRI is not available.
scan is the choice of imaging. MRI sagittal scout film is used
for rapid screening of the surrounding soft tissues.
Patients with persistent back pain in the region of abnormality on
plain spine radiograph, with or without neurological deficits,
should undergo evaluation with MRI. Patients with progressive back
or neck pain whose plain radiograph is normal should also undergo an
imaging study of the epidural space, even if their neurological
examination is normal.
|| D2 met-MRI axial
D2 -met -CT
D8 hyperostotic met-MRI sag
D8 hyperostotic met-MRI
myelogram still is used in situations where MRI is not
available. Myelograms, allow for cerebrospinal fluid (CSF) sampling.
CSF sampling should be deferred if evidence of near/complete spinal
block is noted. The risk of having neurological deterioration after
myelogram is about 14%. Neurological deterioration is less likely
with C1-2 puncture.
scan findings are positive in 60% of cases.
Needle or open
biopsy will establish the diagnosis.
thorough metastatic workup is paramount in patients with
spinal metastasis. This helps to delineate the nature and the
extensiveness of the systemic disease; however, the appropriateness
of diagnostic tests depends on the amount of time available. In
patients with rapidly progressing symptoms, chest x-ray and physical
examination is all that is permitted. The patient should then have a
plain x-ray of the entire spine, followed by MRI with and without
treatment is high-dose dexamethasone and analgesics. The
optimal dexamethasone dose has not been established, but in practice
the usual dose is 4 mg hourly after a loading dose of 24mg. Of all
the corticosteroids, dexamethasone has the least mineralocorticoid
effect and is least likely to be associated with infection or
cognitive dysfunction, although it does increase the risk of
myopathy. The frequency of complications from steroid therapy is
dependent on the duration of the treatment and is associated with
hypoalbuminemia. Treatment lasting more than 3 weeks is more likely
to be associated with complications. Hypoalbuminemia appears to
increase the risks of adverse effects associated with steroid
70-80% of patients experience improvement of symptoms within 48
hours of treatment. Approximately 64% of patients report alleviation
of pain within 24-48 hours of starting steroid therapy and 57% show
improvement in their motor function. In most cases steroid use needs
to be continued until the completion of radiotherapy.
remains the mainstay of treatment for spinal metastatic
disease. Most of the lymphoreticular tumors and prostate carcinoma
are radiosensitive; lung and breast are less sensitive. Tumors of
the gastrointestinal system and kidney are resistant to
radiotherapy, as are melanomas.
radiotherapy has been offered to the latter group of patients and
has demonstrated some response. The radiation port normally includes
2 vertebral bodies above and below the diseased segment. 1000-1200
rads a week in divided doses for 3-4 weeks, for an average total of
3200 rads is the usual dose. About 80% of patients with pretreatment
pain have symptomatic relief; 48% of patients with motor or
sphincter dysfunction respond to treatment.
Most often surgery is indicated only as a stabilization
procedure or for tissue diagnosis. It is employed in patients who
have disease progression despite radiotherapy and in those with
known radiotherapy-resistant tumors.
The patient should
be suitable for adjuvant therapy.
The results of
surgery are superior to those of irradiation alone. Relief of pain
and restoration of neurological deficit are respectively 82% and 70%
after the surgery, and 56% and 55% after the irradiation. The
duration of survival following surgery tended to be related to
primary tumor. Minimal survival is achieved in lung carcinoma, and
maximum survival is achieved with prostate carcinoma. Although the
surgery of bone metastasis does not necessarily affect the life
expectancies of the patients, adequate surgery is often able to
provide a patient with several years of pain-free, mobile and useful
deficit and back pain are caused not only by cord or root
compression, but also by skeletal instability. Therefore, the
surgical results after the decompression and stabilization were
superior to those after the decompression alone when they were
evaluated on the basis of pain relief and restoration of
selection of a surgical approach is influenced by
the primary site and extent of osseous and neural
involvement and the patient's preoperative
neurological and clinical status.
current trend is to decompress anteriorly (vertebrectomy,
corpectomy) for anteriorly placed lesions. It is
always combined with reconstruction and and
stabilization with instrumentation.
is indicated less commonly than these other
procedures, because most of the lesions are
anteriorly based, and posterior decompression may
further destabilize the spine.
a potentially curable lesion, a combined anterior
and posterior decompression may be indicated.
Titanium cage & compression screws- AP
Titanium cage & compression screws- Lat
Stabilization with instrumentation
decompression and stabilization together with radiotherapy is
offers stabilization of the diseased bone and allows ambulation
together with pain relief. Patients with nonambulatory status at
diagnosis do poorly, as do patients with more than one vertebra
cases, chemotherapy helps as an adjuvant to surgery and
radiation. Hormone therapy, as in secondaries due to
prostatic carcinomas, give good palliation.
outcome of metastatic disease to the spine and associated structures
is uniformly bleak.
median survival duration for patients with spinal metastatic disease
is 10 months.
morbidity of spinal metastatic disease is of significance,
especially in patients with paralysis and/or bowel and bladder
involvement. The latter compromises the quality of life of patients
with cancer and puts an additional burden on the caregiver.
ultimate goals are to maintain the independence and dignity of the
patient and to optimize his or her comfort level.
treatment has been proven to increase the life expectancy of
patients with spinal metastasis. The goals of therapy are pain
control and functional preservation. The most important prognostic
indicator for spinal metastases is the initial functional score. The
ability to ambulate at the time of presentation is a favorable
prognostic sign. Loss of sphincter control is a poor prognostic
feature and is mostly irreversible.
therapy is more effective in achieving pain control (67%) than
surgery (36%). Notably, surgery alone is the least effective way to
treat spinal metastases. About 20-26% of patients who undergo
surgery experience further deterioration in terms of either mobility
or sphincter control while only 17% in the radiation therapy group
experience further deterioration.
intervention with extensive reconstruction should be employed only
after thorough evaluation of the extent of the systemic disease and
with a clear understanding of the realistic expectation of the
patients and their caretakers.