The study is aimed at comparative analysis of two frequently used duraplasty materials: one is made out of bovine pericardium, and the other - from bovine collagen derived from bovine achilles tendon. Both materials are routinely used form this intervention (duraplasty), but the question of superiority of one over the other remains open. This study follows patients with Chiari malformation from the time of surgery to the time of their discharge from the hospital and then another 3 months of follow up care.
