User:Gth674b/Tarlov cyst

[[[[ Tarlov cyst, aka perineurial cysts, are ...

General Information
Tarlov cysts, also known as perineurial cysts, are cerebrospinal fluid filled sacs located in spinal canal of S2 to S4 region of vertebrae, and are distinguished from other meningeal cysts by nerve-fiber filled walls. Tarlov cysts are defined as cysts formed within the nerve root sheath at dorsal root ganglion.

Classification
Tarlov cysts are considered Type II leisons and are defined as extradural meningeal cysts with nerve fibers. Nabros et all classified spinal cysts in three different types. Type I spinal cysts are extradural meningeal cysts without nerve root fibers. Type II Spinal cysts correspond to Tarlov cysts and are defined as extradural meningeal cysts with nerve fibers. Type III Spinal Cysts contains intradural meningeal cysts

Appearance
The walls of Tarlov cysts are thin and fibrous; they are prone to rupture if touched, making surgery difficult. The nerve fibers that are embedded in the walls of the cysts has the appearance and size of dental floss. The nerve fibers in the walls are usually not arranged in any specific alignment. Histologic examination reveals the Tarlov cyst outer wall is composed of vascular connective tissue, and the inner wall is lined with flattened arachnoid. In addition, part of the lining containing nerve fibers also occasionally contains ganglion cells. The cysts can contain anywhere from a couple milliliter of CSF to over 2.5 liters liters of CSF.

location
Tarlov cysts are located in the S2 and S4 region of the spinal cord. They usually occur on the extradural components of sacrococcygeal nerve roots at the junction of dorsal root ganglion and posterior nerve roots and arise between the endoneurium and perineurium. Occasionally, these cysts are observed in the thoracic spine. However, these cysts most commonly arise at the S2 or S3 junction of the dorsal nerve root ganglion. The cysts are often multiple, extending around the circumference of the nerve, and can enlarge over time to compress neighboring nerve roots to cause bone errosions.

Difference between Tarlov Cysts and other Spinal Meningeal Cysts
The following table is compilation of some key differences between Tarlov Cysts, meningeal cysts and arachnoid diverticula cysts. Although the definitions for each entity are still controversial, the following tiems are generally accepted by surgeons and experts.

Symptoms
Tarlov Cysts are not usually symptomatic; the cases of reported symptomatic Tarlov Cysts ranges from 15% to 30% of the overall reported Tarlov Cyst Cases depending on the source of literature. Nevertheless these cysts are important clinical entities because of its tendency to increase in size over time, potentially causing complications and eroding the surrounding bone tissue. Patients with symptomatic Tarlov cysts can be divided into 3 categories according to their symptoms :

Group 1 - Pain on tailbones that radiates to the legs

Group 2 - Pain on bones, legs, sexual dysfunctions, and dysfunctional bladder

Group 3 - No pain, just sexual dysfunction and dysfunctional bladder

Common symptoms
Below are a list of commonly reported symptoms associated with Tarlov cysts:

backpain, perineal pain, Sciatica, Cauda Equina syndrome, dysuria, urinary incontinence, coccygodynia, sacral radiculopathy, radicular pain, headachs, retrograde ejaculation, paresthesia, hypesthesia, motor disorders in lower limbs and the genital, perineal, or lumbossacral areas, sacral or butttocks pain, vaginal or penile paraesthesia, sensory changes over buttocks, perineal area, and lower extremity

Formation
There are several hypotheses proposed regarding the formation of Tarlov cysts, including: inflammation within the nerve root cysts followed by inoculation of fluids, developmental or congenital origin, arachnoidal proliferation along and around the exiting sacral nerve root, and breakage of venous drainage in the perineuria and epineurium secondary to hemosiderin deposition after trauma Tarlov himself theorized that the perineurial cysts form as a result of blockage of venous drainage in the perineurium and epineuriium secondary to hemosiderin deposition after local trauma  Over the last decade, another theory gaining increasing popularity over the past decade is one postulated by Fortuna et al whish described perineural cysts to be the results of congenital arachnoidal proliferation along the exiting sacral nerve roots.

Theories for Tarlov Cyst enlargement
Tarlov cysts are known to have the tendency to enlarge over time. The prominent theory that explains this phenomenon reasons the enlargement of the cysts is due to the cerebrospinal fluid being pushed into the cyst during systole pulsation but unable to get out during diastole, resulting in enlargement over time. However, this theory has yet to be tested. Although growth in the cysts occur, it is still unknown to how often, or at what condition these cyst form, or if any underlining condition is essential for the formation and enlargement of these cysts. Nevertheless the enlargement of these cysts do pose potential treat to the health of the patient from the continuous pressure in which it exert will erode the bone.

Detection
Both CT and MRI are good imaging procedures that allow the detection of extradural spinal masses such as Tarlov cycsts. In fact, most of the cysts are asymptomatic and are found incidentally during CT or MRI examinations for other reasons.

MRI
MRI, or Magnetic Resonance Imaging, is considered the imaging study of choice in identifying Tarlov Cysts. MRI provides better resollution of tissue density, absence of bone interference, multiplanar capabilities, and is noninvasive. Plain films may show bony errosions of the spinal canal or of the sacral foramina.

CT
CT, or computed tomography scan is another examination method often used for the diagnosis of Tarlov cyst. Unenhanced CT scans may show sacral erosions, asymmetric epidural fat distribution, and cystic masses that are isodense with CSF (cereberol Spinal Fluid). CT Myelogram is minimally invasive, and could be employed when MRI cannot be performed on patient.

Misdiagnosis
The term Tarlov cysts, or 'sacral perineural cyst', has often been misusesd as referring to other cystic lesion in the sacral region. Tarlov cysts are often detected through MRI or CT Myelography; these tools are very useful in spotting cysts at the region, but they cannot distinguish one major difference between Tarlov cysts and other cysts - the fact the walls contains nerve fibers. Therefore, the final diagnosis of a Tarlov cyst is not a radiological but rather a histopathological diagnosis These cysts are sometimes also misdiagnosed as lumbar disc herniation or lumbar spinal stenosis, especially when they are pressing on the S-1 nerve root.

Treatment
There are a handful of treatments available for Tarlov Cysts. The two treatment types are the extraction of cerebralspinal fluids from the cyst, and the complete removal of cyst from area. The first option is more commonly recommended to patients because the removal of the nerve-fiber filled cystic wall may potentially interfere with the functioning of nervous system.

Mention about the 1.5cm thing

Nevertheless, all types of surgical treatment poses common danger, including nerve damage, infection, head-ach caused by leakage of cerebralspinal fluids, and inflammation. Below are some of practices for the treatment of tarlov cysts.

Bony Decompression
brief description and risk will be provided

Cautery of cystic wall
brief description and risk will be provided

Complete excision of cyst along with nerve root involved
brief description and risk will be provided

cyst fenestration
brief description and risk will be provided

inbrication or oversewing of the cyst wall
brief description and risk will be provided