PRNP and Creutzfeldt Jacob disease: Algorithms used for planning any type of surgery having the potential to contaminate instruments incorporate the following two main variables: 1) patient-related infectious risk level (based on personal assessment, e.g., patients with PRNP mutations or family history of CJD, or cases where diagnosis of sCJD has been considered due to clinical symptoms), and, 2) the putative contaminating power of the planned procedure (extrapolated from the infectivity level assigned to tissues to be contacted by reusable instruments) [13,19].