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

Object. Tarlov or perineurial cysts are lesions of the nerve root most ofte n 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 assesse d the outcome and efficacy of cyst wall resection in 10 patients with sympt omatic Tarlov cysts. The medical literature is reviewed, theories of origin are evaluated, and suggestions as to their cause and pathogenesis are offe red. Methods. Ten consecutive patients harboring symptomatic Tarlov cysts were t reated by the senior author between 1989 and 1999. All patients were assess ed for neurological deficits and pain by neurological examination and visua l analog scale, respectively. Computerized tomography myelography was perfo rmed in all patients to diagnose delayed filling of the cysts. A sacral lam inectomy with resection of the sacral cyst or cysts was performed in all pa tients. Resected material from eight of 10 patients was submitted for histo pathological evaluation. Seven (70%) of 10 patients obtained complete or su bstantial resolution of their symptoms, with an average follow up of 31.7 m onths. All of these patients had Tarlov cysts larger than 1.5 cm in diamete r, producing radicular pain or bladder and bowel dysfunction. Three (30%) o f 10 patients experienced no significant improvement. All three patients ha rbored 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 c ells in 25% of cases, and evidence of old hemorrhage in half. Conclusions. Large cysts (> 1.5 cm) and the presence of associated radicula r symptoms strongly correlate with excellent outcome. Tarlov cysts may resu lt from increased hydrostatic pressure and trauma.