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.