Medical hypotheses
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Tarlov cysts (TCs) consist of dilated nerve root sheaths filled with cerebrospinal fluid (CSF) and are most frequently found in the sacrum. It is estimated that 25% of detected TCs cause chronic pain and intestinal and urogenital symptoms due to compression of the sacral nerve root fibers inside the TC. Unfortunately, symptomatic TCs are frequently overlooked. ⋯ While increased intracranial pressure causes dilation of the ventricles, the associated increased spinal pressure may cause dilation of multiple spinal nerve root sheaths to form TCs. Furthermore, while the increased volume of the ventricles gradually compresses the neurons and axons of the brain against the bony skull, simultaneously, the increased pressure inside the nerve sheaths may also gradually compress the neurons and axons located inside the dorsal root ganglia and spinal nerves, resulting in neuropathic pain, sensory abnormalities, and neurogenic bladder and bowel symptoms. Hydrocephalus patients reporting neuropathic pain should be screened for the presence of TCs.