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Definition and Description
Tarlov cysts (hereafter referred to as TCs) are also known as perineural/perineurial, or sacral nerve root cysts. They are dilations of the nerve root sheaths and are abnormal sacs filled with cerebrospinal fluid (hereafter referred to as CSF) that can cause a progressively painful radiculopathy (nerve pain). They are located most prevalently at the S2, S3 level of the sacrum. The sacrum is a fused triangle-shaped bone comprised of the five sacral vertebrae forming the base of the spine. The five lumbar vertebrae are located just above the sacrum, and the four coccygeal vertebrae are just below the sacrum forming the coccyx or tailbone.
Perineural cysts can form in any section of the spine; a significant percentage (11%) of patients have cysts at more than one location of the spine.. Some patients have cysts at all sections of the spine, including cervical, thoracic, lumbar, and sacral. Other very closely related spinal pathology and symptoms can be due to meningeal diverticulum, meningocele, and pseudomeningocele.
The TCs appear on MRI to be dilated or ballooned areas of the sheaths that cover nerve roots exiting from the sacral region of the spinal column. The cysts are created by the dilated sheaths of the nerve roots directly connected to the subarachnoid area of the spinal column, through which the cerebrospinal fluid flows. There are 3 layers or meninges (coverings) of the brain and spinal cord. They are the dura mater, literally meaning "hard mother" in Latin, which is the outermost , toughest, and most fibrous of the three layers. Next is the arachnoid layer, the middle layer where the spinal fluid flows, and the innermost layer, the pia mater. The space between the arachnoid and pia mater layer is called the subarachnoid space.
Some individuals have TCs visible on a MRI, but have experienced no relevant symptoms, and the cysts are perhaps identified, but are not acknowledged as significant by the radiologist reading the films or by the physician who ordered them. If the patient has no symptoms that might be suggestive of symptomatic TCs, and sometimes even if they do have symptoms, the patient might not be told about the finding on the MRI. It is not unusual, if the cyst has been present for a number of years to see evidence of erosion and remodeling of the sacral bone, or other vertebrae in the spine. When conditions cause these cysts to fill with more spinal fluid and to expand in size, they begin to compress important surrounding nerve fibers; the cysts contain nerve fibers, resulting in a variety of symptoms including chronic pain.
Causes and Symptoms
Although the cause(s) of Tarlov cysts formation is yet scientifically unproven,there are a number of conditions that can create increased spinal fluid pressure, increasing the flow of cerebrospinal fluid into the cysts and causing them to expand in size and create symptoms. The cysts are then termed symptomatic Tarlov Cysts. Some incidents or conditions that might potentially cause the asymptomatic cysts to become symptomatic are traumatic injuries such as falls, automobile accidents , heavy lifting, childbirth, and epidurals. Trauma to the spinal cord, an increase in the CSF pressure, or a blockage of the CSF can result in cyst formation. Read "What happens in spinal cord injuries?" in Our Library. It is also noted that the herpes simplex virus can cause the Tarlov cyst symptoms to worsen during a herpes virus outbreak, but there is no known "connection" related to any virus or infection with causing Tarlov cysts to develop.
There is significant clinical evidence that collagen mutations or connective tissue disorders such as Marfan's, Ehlers-Danlos, Sjogren's, Loeys-Deitz, Lupus, MCTD (mixed connective tissue disorders), UCTD(undifferentiated connective tissue disorders) are predisposing or contributing to the cysts developing. A number of Tarlov cyst patients have also been diagnosed with a connective tissue disorder, and many more of their biological family members, who may or may not have Tarlov cysts, have been diagnosed with one of the above mentioned connective tissue disorders (CTD). A geneticist research group, funded by the Foundation, is currently looking at that potential connection....pun intended.
Symptoms of expanding/enlarging cysts occur due to compression of nerve roots that exit from the sacral area. Symptoms may include the following, dependent on the location of the cysts and the section of the spine they occur:
Pain in lower back (particularly below the waist) and in buttocks, legs, and feet
Pain in the chest, upper back, neck, arms and hands
Weakness and/or cramping in legs and feet / arms and hands
Paresthesias (abnormal sensations) in legs and feet or arms and hands, dependent on cyst locations
Pain sitting or standing for even short periods of time
Pain when sneezing or coughing
Inability to empty the bladder or in extreme cases to urinate at all
Bowel or bladder changes, including incontinence
Swelling over the sacral (or cervical, thoracic, or lumbar) area of the spine
Soreness, a feeling of pressure and tenderness over the sacrum and coccyx (tailbone), extending across the hip and into the thigh with cysts in the sacrum. Same feelings in upper sections of the spine dependent on cyst locations
Headaches (due to the changes in the CSF pressure) and sometimes accompanied by blurred vision, double vision, pressure behind the eyes and optic nerve pressure causing papilledema (optic nerve swelling)
Other sensory system symptoms: Tinnitus/Ear noises (ringing, buzzing, snapping,popping, cricket sounds,etc.)
Dizziness and feeling of loss of balance or equilibrium, especially with change of position
The feeling of sitting on a rock
Pulling and burning sensation in coccyx (tailbone) area, especially when bending
Vaginal, rectal, pelvic and/or abdominal pain
Restless leg Syndrome
PGAD (Persistent Genital Arousal Disorder)
Sexual dysfunction and painful intercourse
The sciatic nerve is the longest nerve in the body and it originates at the S2, S3 level of the spinal column. It crosses the buttocks and extends down the leg into the foot. Sciatica is a syndrome that results in burning, tingling, numbness, stinging, electrical shock sensations in the lower back, buttocks, thigh, and pain down the leg and foot. Severe sciatica may also result in weakness of the leg and foot.
Some TCs don't cause symptoms and are not diagnosed. However, when symptoms develop that are suggestive of TCs, MRI will demonstrate their presence, and Myelogram or CT may demonstrate the CSF flow between the spinal subarachnoid area and the cyst, determining how rapidly the open communicating/wide neck cyst is filling and whether or not the fluid is freely flowing in and/or out of the cyst.
Diagnosis and Treatment
Most Tarlov cysts are discovered on MRI, CT or Myelogram. The best imaging study to image the Tarlov/perineural cyst is a "spine MRI", and since the vast majority (95%) of the perineural cysts are on the sacral spine, then the order should be for a "full sacral spine MRI (S1-S5) all the way to the coccyx/tailbone". Additionally, the ordering physician should request the radiologist to "look for the presence of Tarlov/perineural cysts, and if any are imaged, to report the cysts and their specific locations, sizes and numbers.
If the patients symptoms are related to the upper sections of the spine(although the cysts occur much less frequently in these areas (3-6%), then the appropriate cervical, thoracic or Lumbar MRI should be ordered. Some patients have the cysts in more than one section of the spine. It is sometimes confusing to make an accurate diagnosis as to the cause of the symptoms, if there are multiple diagnoses found, such as herniated discs, ruptured disc, DDD (degenerative disc disease). It is sometimes diagnostically conclusive that the cysts are the cause of symptoms, when pain is improved by aspirating the fluid from the cysts. Although using a needle to aspirate CSF from the cysts can temporarily relieve symptoms, eventually the cysts will refill and the symptoms will recur usually within hours.
Pain may be also temporarily controlled by aspiration of the cysts and then injecting the cysts with fibrin glue (a substance produced from blood chemicals involved in the clotting mechanism). The aspiration of CSF and injection of fibrin glue procedure theoretically is designed to remove the CSF from the cyst, and to block the entrance or the neck of the cyst with the sealant glue, to prevent return of the flow of CSF into the cyst. Some patients have found immediate relief after the procedure, while others have reported a delayed benefit from the procedure when the nerve irritation has subsided. After the procedure, there are outcomes of both short term relief, as well as longer term relief reported. However, it is considered to be a temporary relief procedure.
Transcutaneous Electrical Nerve Stimulation (TENS) has been proven useful for some in pain management. TENS devices deliver electrical impulses through the skin to the cutaneous (surface) and afferent(deep) nerves to control pain. Unlike medications and topical ointments, TENS does not have any known side effects, other than skin irritation from the electrodes seen in some patients.
How does TENS control Pain?
There are two major theories as to how electrical stimulation relieves pain. According to the "gate control theory", pain and non-pain impulses are sent to the brain from the local nervous system. These pulses travel through the cutaneous nerves to the deeper afferent nerves and then to the spinal cord and brain. The gates prevent the brain from receiving too much information too quickly. Since the same nerve cannot carry a pain impulse and a non-pain impulse simultaneously, the stronger, non-pain impulse (from the TENS device) "controls the gate". According to the second theory, TENS stimulation encourages the body to produce natural painkillers called endorphins. These chemicals interact with receptors, blocking the perception of pain. This is similar to the way the drug Morphine works, but without the side effects associated with the pharmaceutical drug.
Some patients report that changes in their diet and/or the addition of nutritional supplements to alter acid-base balance (alkalinity/acidity) in the body may have helped with symptoms; however, there have been no scientific studies in Tarlov cyst patients to prove any benefit with dietary changes or dietary supplements.
Pain medications plus medications used to treat chronic nerve related pain (such as antiseizure medications and antidepressants) may be helpful in some patients. NSAIDs (non-steroidal anti-inflammatory drugs) are an important adjunct to the treatment to help with nerve inflammation and irritation.
Lidoderm patches used for shingles/post herpetic neuralgia (PHN) may be applied locally over the sacral area to provide some temporary relief of discomfort sitting and assistance with pain management. In Europe, this same product is marketed under the name Neurodol.
When pain is intractable, despite a variety of interventions, or when other neurological symptoms become severe (ie bowel and bladder dysfunction, severe paraesthesias,etc.), and the sacrum is eroding and remodeling, surgery may be the treatment of choice. There are a small number of physician's in the world who have surgical expertise in the treatment for TCs, and the short-term and long-term outcome of surgery is improving but variable in individual patients at this time. The usual surgical procedure consists of fenestration and imbrication of the cysts and then packing all the dead space around the cysts with fat, glue, and/or muscle. The body does not like dead spaces, and new cysts will possibly develop in the dead spaces around the old cysts, if not filled. Due to the potential risks for further nerve damage or spinal fluid leaks, there might be increased symptoms postoperatively, including more bowel and bladder problems, when the cysts are located in the S2-S3 nerve location. However, the neurosurgeons are perfecting surgical techniques and including intra-operative nerve monitoring to decrease the risks of further nerve damage. Due to the long term nerve compression causing irritation and inflammation to the nerves, it may take months to a year to determine the full benefit of the surgery.
Neurosurgeons and interventional neuroradiologists may treat individuals with TCs, if they are knowledgeable about the symptomatology of the cysts and the extended ramifications of untreated cysts that are present with no other spinal pathology. NOTE: See "Find a Dr." page on the website.
It is important for any other spinal pathology to be ruled out as a possible cause of symptoms.But, when cysts are visualized on MRI films and there is no other spinal pathology found to be the cause of the symptoms, it is important to refer the patient to someone who is familiar with the pathology and treatment of TCs. Pain management specialists are vital to the pain management of symptomatic Tarlov cysts; family practice physicians play a key role in management of symptoms, including bowel and bladder dysfunction.
A urologist might be consulted if the cysts are interfering with bladder function with such issues as urinary retention or residual resulting in increased frequency of UTI, and in some cases the necessity to self catheterize. The opposite urinary problem might occur and result in incontinence (inability to control leakage of urine).
Prognosis of Symptomatic Tarlov Cysts
Those who have progressive and prolonged symptoms run a risk of neurological damage, if the cysts continue to compress nerve structures. If the nerve damage is progressive and affects bladder and bowel function and other body systems, it is important to have a good primary physician to coordinate referrals to specialists. Many patients become disabled and unable to continue to work, due to the pain and multi-systems affected issues.Individuals who undergo neurosurgery or those who have the cysts aspirated and injected with fibrin glue have varied results from no improvement to moderate improvement, but in some cases have worsened symptoms and more nerve damage from the procedures. There are also some patients who are much improved, evidenced by an increase in activities without the severity of symptoms recurring, and the need for less medications.There is no scientific analysis to date of all the compiled reports from the various procedures. The Foundation is working with the physicians and the researcher to provide collaboration, communication and an improved database of results of treatments. Some physicians are tracking outcomes and results can be found on their individual websites.
Collaboration of those very few members of the medical community who are willing to treat Tarlov cysts, as well as improved continuing medical education (CME) is essential to improve the short and long term prognosis of those diagnosed with Tarlov cysts.
The sharing of scientific data from procedures they have performed will aid in developing improved treatment outcomes and in educating the medical community about this devastating and life altering diagnosis. Promoting dedicated research to determine cause and treatment for an improved outcome and prognosis of Tarlov cysts is one of the primary goals of the Tarlov Cyst Disease Foundation.
Dr. Frank Feigenbaum Discusses Tarlov Cysts:
American Chronic Pain Association
Encyclopedia of Neurological Disorders
National Institutes of Health (NIH)
National Institute of Neurological Disorders and Strokes (NINDS)
Sacral Nerve Root Cysts, Isadore M. Tarlov
Personal experiences of those diagnosed with Tarlov cysts
TENS user manual (EMPI)