Answer to the Letter to the Editor of F.-A. Dauchy et al. concerning manuscript "Intradural extramedullary primary hydatid cyst of the spine: a case report and review of literature". Eur Spine J, doi:10.1007/s00586-012-2373-1 by I. Lotfinia, S. Sayyahmelli, A. Mahdkhah, M. Shoja M (2012)