Prevalence and percutaneous drainage of cysts of the sacral nerve root sheath (Tarlov cysts).

PURPOSE To describe a percutaneous CT-guided method for drainage of perineurial (Tarlov) cysts, which are a cause of sciatica and low back pain, and to report the prevalence of these cysts within the population as detected by MR. METHODS Five hundred sequential lumbosacral spine MRs were evaluated for the presence of a perineurial cyst. Using CT-guided percutaneous drainage techniques, seven cysts were drained in five symptomatic patients. RESULTS Of the 500 sequential lumbosacral spine MRs, examinations from 23 patients showed perineurial cysts, a prevalence of 4.6%. Five patients (1%) were symptomatic from the cysts. After CT-guided percutaneous drainage, instant pain relief lasted from 3 weeks to 6 months without the risk or cost of spine surgery. CONCLUSIONS Lumbosacral perineurial cysts are common lesions that are usually asymptomatic but may cause pressure symptoms. Cyst puncture can alleviate the pain. Although the cysts repressurized and the patients' symptoms returned in most cases, this technique seems to be a quick and simple way of at least attaining a pain-free interval and possibly a complete cure as occurred in one patient in this study.