Keywords: Chiari type I malformation; posterior fossa decompression; duraplasty; CSF leak; CSF collection; postoperative fistula Posterior fossa decompression (PFD) is the treatment of choice for patients affected by Chiari type I malformation (CM-I) who present with Chiari-related symptoms (CM-I syndrome1) and/or syringomyelia.2,3 The association of PFD with enlargement duraplasty (PFDD)—although judged to be more effective in treating CM-I symptoms and resolving syringomyelia than bone...