Thank you Andras for such a complete answer. It is great. I have read a paper that compared osteotomies of free-hand surgery, patient specific surgical guides (PSSG) and navigation systems and said that osteotomies with PSSG were the most accurate. In addition to that they don’t need navigation hardware and can be made with a desktop 3d printer in biocompatible PLA and esterilized with EtO or Gamma rays. Another question for you is: Is it possible to develop PSSG on Slicer?