Tarlov Cyst
November, 2006
Tarlov
cysts are fluid-filled nerve root cysts found most commonly at the
sacral level of the spine – the vertebrae at the base of the spine.
These cysts typically occur along the posterior nerve roots. Cysts can
be valved or nonvalved. The main feature that distinguishes Tarlov cysts
from other spinal lesions is the presence of spinal nerve root fibers
within the cyst wall, or in the cyst cavity itself.
Due
to the close proximity to the lower pelvic region, patients may be
misdiagnosed with herniated lumbar discs, arachnoiditis, and in females,
gynecological conditions. An accurate diagnosis may be further
complicated if the patient has another condition that affects the same
region.
Incidence and Prevalence
Small, asymptomatic Tarlov cysts are actually present in an
estimated 5 to 9 percent of the general population. However, large cysts
that cause symptoms are relatively rare. Tarlov cysts were first
identified in 1938, yet there is still very limited scientific knowledge
available.
In a recent Tarlov cyst survey, an estimated
86.6 percent of respondents were female, and 13.4 percent were male.
This condition affects women far more frequently than it affects men.
The largest majority of respondents were ages 31 to 60, with a combined
total of 80.4 percent in that age demographic.
An
estimated 33 percent of respondents had a cyst(s) present in other parts
of the body, most commonly the abdomen or hand and wrists.
An estimated 3 percent of respondents had no pain; 4.2 percent
categorized their pain as very mild; 7.6 percent as mild; 31.5 percent
as moderate; 38.6 percent as severe; and 15.1 percent as very severe.
Source:
Tarlov
Cyst Support Group, Tarlov Cyst Survey
Causes
Although the exact cause is
unknown, there are theories as to what may cause an asymptomatic Tarlov
cyst to produce symptoms. In several documented cases, accidents or
falls involving the tailbone area of the spine caused previously
undiagnosed Tarlov cysts to flare up.
Symptoms
An increase in pressure in or on the cysts may
increase symptoms and cause nerve damage. Sitting, standing, walking,
and bending are typically painful, and often, the only position that
provides relief, is reclining flat on one’s side. Symptoms vary greatly
by patient, and may flare up and then subside. Any of the following may
be present in patients that have symptomatic Tarlov cysts.
- Pain in the area of the nerves
affected by the cysts, especially the buttocks
- Weakness
of muscles
- Difficulty sitting for prolonged periods
- Loss of sensation on the skin
- Loss of
reflexes
- Changes in bowel function such as
constipation
- Changes in bladder function including
increased frequency or incontinence
- Changes in sexual
function
Diagnosis
Tarlov cyst is
difficult to diagnose because of the limited knowledge about the
condition, and because many of the symptoms can mimic other disorders.
Most primary care physicians would not consider the possibility of
Tarlov cyst. It is best to consult a neurosurgeon with experience in
treating this condition.
Tarlov cysts may be discovered
when patients with low back pain or sciatica have a magnetic resonance
imaging (MRI) performed. Follow-up radiological studies, in particular,
computed tomographic (CT) myelography are usually recommended.
If a patient has bladder problems and seeks medical help from
an urologist, there are tests that can help diagnose Tarlov cyst. The
standard urological tests for Tarlov cyst help determine if the patient
has a neurogenic (malfunctioning) bladder. In urodynamics, the bladder
is filled with water through a catheter and the responses are noted.
Cystoscopy involves inserting a tube with a miniature video camera into
the bladder via the urethra. A neurogenic bladder shows excessive
muscularity. A third possible test is a kidney ultrasound to see if
urine is backing up into the kidneys.
Nonsurgical
Treatment
Nonsurgical therapies include lumbar
drainage of the cerebrospinal fluid (CSF), CT scanning-guided cyst
aspiration, and a newer technique involving removing the CSF from inside
the cyst and then filling the space with a fibrin glue injection.
Unfortunately, none of these procedures prevent symptomatic cyst
recurrence.
Surgery
Tarlov
cyst surgery involves exposing the region of the spine where the cyst
is located. The cyst is opened and the fluid drained, and then in order
to prevent the fluid from returning, the cyst is occluded with a fibrin
glue injection or other matter.
Neurosurgical techniques
for symptomatic Tarlov cysts include simple decompressive laminectomy,
cyst and/or nerve root excision, and microsurgical cyst fenestration and
imbrication.
The authors of one study found that
patients with Tarlov cysts larger than 1.5 cm and with associated
radicular pain or bowel/bladder dysfunction benefited most from surgery.
The benefits of surgery should always be weighed carefully against its
risks.
Outcome
Postoperative
CSF leak is the most common complication, but in some cases, these
leaks may self-heal. Patients may be advised to stay in bed with the
foot of the bed raised, and to wear a corset to control swelling.
Although it is low, there is a risk of developing bacterial meningitis.
Although some patients have noted a considerable decrease in pain, the
most common negative outcome is the failure of the surgery to eliminate
the symptoms. In some cases, the surgery may cause an existing symptom
to worsen or it may cause a new one.
When all treatment
options have been exhausted, it is very important for the patient to
make any necessary lifestyle changes and to undertake a pain management
strategy with his or her physician. Supervised pain management, as well
as support groups, can help a patient cope and improve his or her
quality of life.
Tarlov Cyst Resources
Tarlov Cyst Association