Tarlov cysts are fluid-filled sacs that develop along nerve roots, most often in the sacral region at the base of the spine. While often present without causing issues, they are frequently discovered incidentally during imaging for other conditions. These cysts are typically benign and usually do not cause noticeable symptoms.
Understanding Tarlov Cysts
Tarlov cysts originate as dilations of the nerve root sheath, specifically within the perineural space, and are filled with cerebrospinal fluid (CSF). Cerebrospinal fluid is the clear fluid that surrounds the brain and spinal cord. A distinguishing feature of these cysts is the presence of spinal nerve root fibers within their walls or cavity. These cysts are relatively common, found in an estimated 5 to 9 percent of the general population, yet most individuals remain unaware of their presence due to their asymptomatic nature.
Defining Large Tarlov Cysts
There is no single universally accepted size that defines a “large” Tarlov cyst. Clinical significance is determined by whether the cyst causes symptoms due to its impact on surrounding structures.
While any size can potentially be symptomatic, larger cysts are more likely to compress nearby nerves or erode bone, leading to clinical issues.
Sizes considered significant in clinical contexts range from 1.5 centimeters in diameter or larger, as these are often associated with symptoms. Some reported cysts can be several centimeters, occasionally reaching up to 10 centimeters.
Imaging techniques like MRI and CT scans measure the cyst’s dimensions.
Symptoms Associated with Large Cysts
When Tarlov cysts grow large enough to compress spinal nerves or surrounding tissues, they can cause a variety of symptoms.
Patients may experience pain in the lower back, buttocks, legs, or perineal area. This discomfort can manifest as a burning or shocking sensation that radiates down the legs, often referred to as sciatica.
Nerve compression can also lead to neurological deficits. These include numbness, weakness, or altered sensations (paresthesia) in the legs and feet, or a loss of reflexes.
Additionally, large cysts may affect bowel and bladder function, potentially causing issues such as urinary incontinence, difficulty emptying the bladder, or constipation. Sexual dysfunction can also occur in some cases.
Symptoms may worsen with activities that increase cerebrospinal fluid pressure, such as sitting, standing, walking, coughing, or sneezing.
Diagnosis and Monitoring
Tarlov cysts are primarily diagnosed using advanced imaging techniques. Magnetic Resonance Imaging (MRI) is the most effective method, providing detailed images of the spine that reveal the cyst’s size, location, and relationship to adjacent nerve structures. CT scans can also be utilized when MRI is not feasible. A neurological examination is an important part of the diagnostic process, assessing the patient’s symptoms and nerve function. For symptomatic cysts, regular monitoring is recommended to track changes in size or symptom progression, guiding management decisions.
Treatment Approaches for Symptomatic Cysts
Treatment for Tarlov cysts is typically considered when they are symptomatic. Initial management often involves conservative approaches, such as pain medication to alleviate discomfort. Physical therapy may also be recommended to help manage symptoms and improve mobility. For more severe or persistent symptoms, several interventional procedures are available. These can include aspiration, which involves draining the fluid from the cyst to relieve pressure on the nerves. Another option is the injection of fibrin glue into the cyst, intended to seal it off and prevent refilling. Surgical decompression, such as a laminectomy, may be considered to reduce pressure on the affected nerve roots. Treatment decisions are highly individualized, based on the severity of symptoms and specific characteristics of the cyst.