What are Tarlov Cysts?

Tarlov cysts, also known as perineural cysts, are fluid-filled sacs that most commonly affect the nerve roots in the sacral region of the spine. While often asymptomatic, a symptomatic Tarlov cyst can be a source of significant distress. These cysts are typically found incidentally during imaging for other conditions, but when they grow large enough to compress surrounding nerves, they can lead to a variety of symptoms. Their formation is believed to be related to the nerve sheath, often occurring near the dorsal root ganglion.

Symptoms and Associated Pain

The primary symptom associated with symptomatic Tarlov cysts is chronic pain. This pain can manifest in various ways, including radicular pain that radiates down the legs, buttocks, or perineum, often worsening with sitting or standing. Neuropathic pain, tingling, numbness, and weakness can also occur, reflecting the compression of the delicate nerve roots. Bladder, bowel, and sexual dysfunction are also possible, depending on the affected nerves. The intensity of this pain can range from mild discomfort to debilitating agony, significantly impacting a person's quality of life.

The Connection to CSF Leaks

In some instances, Tarlov cysts can be implicated in the development of a spontaneous cerebrospinal fluid (CSF) leak. The walls of these perineural cysts are often thin and contiguous with the dural sac, which contains CSF. If a cyst ruptures or develops a small defect, it can lead to a persistent CSF-leak. Such leaks can cause intracranial hypotension, resulting in symptoms like orthostatic headache, neck stiffness, dizziness, and nausea. Diagnosing a CSF leak related to a Tarlov cyst requires specialized imaging and expertise from medical professionals.

A Rare Complication: Superficial Siderosis

A severe and rare complication associated with chronic CSF leaks, particularly those involving bleeding, is superficial siderosis. This condition occurs when there is persistent leakage of blood into the CSF, leading to the deposition of iron pigment (hemosiderin) on the surface of the brain and spinal cord. This iron deposition can cause progressive neurological damage, manifesting as ataxia, sensorineural hearing loss, and myelopathy. While Tarlov cysts themselves don't directly cause superficial siderosis, their potential to cause chronic CSF leakage and associated microhemorrhages creates a pathway for this serious development. Early detection and treatment of the underlying CSF leak are crucial to prevent or halt the progression of superficial siderosis.

Diagnosis and Management

Diagnosis of Tarlov cysts typically involves magnetic resonance imaging (MRI) of the spine. Symptomatic cysts are often identified based on their size and location in relation to compressed nerve roots. Management strategies vary, ranging from conservative approaches like pain management and physical therapy to more invasive interventions such as aspiration, fibrin glue injection, or surgical fenestration and wrapping of the cyst. The decision for treatment depends heavily on the severity of symptoms, the presence of a CSF-leak, and the overall impact on the individual's health and well-being.