Tarlov cysts: a study of 10 cases with review of the literature.

OBJECT: Tarlov or perineurial cysts are lesions of the nerve root most often found in the sacral region. Although there is agreement that asymptomatic Tarlov cysts should be followed, it is still debated whether patients with symptomatic Tarlov cysts should be treated surgically. The authors assessed the outcome and efficacy of cyst wall resection in 10 patients with symptomatic Tarlov cysts. The medical literature is reviewed, theories of origin are evaluated, and suggestions as to their cause and pathogenesis are offered.
METHODS: Ten consecutive patients harboring symptomatic Tarlov cysts were treated by the senior author between 1989 and 1999. All patients were assessed for neurological deficits and pain by neurological examination and visual analog scale, respectively. Computerized tomography myelography was performed in all patients to diagnose delayed filling of the cysts. A sacral laminectomy with resection of the sacral cyst or cysts was performed in all patients. Resected material from eight of 10 patients was submitted for histopathological evaluation. Seven (70%) of 10 patients obtained complete or substantial resolution of their symptoms, with an average follow up of 31.7 months. All of these patients had Tarlov cysts larger than 1.5 cm in diameter, producing radicular pain or bladder and bowel dysfunction. Three (30%) of 10 patients experienced no significant improvement. All three patients harbored Tarlov cysts smaller than 1.5 cm in diameter, producing nonradicular pain. Histopathological examination was performed on specimens from eight of 10 patients, which demonstrated nerve fibers in 75% of cases, ganglion cells in 25% of cases, and evidence of old hemorrhage in half.
CONCLUSIONS: Large cysts (> 1.5 cm) and the presence of associated radicular symptoms strongly correlate with excellent outcome. Tarlov cysts may result from increased hydrostatic pressure and trauma.