These “computer assisted surgical templates” are personalized guides made of biocompatible polymeric material, manufactured with 3D print technology. Their purpose is to improve different kind of freehand operating procedures. It is designed on the basis of CT imaging of individual patient bone by using special software (EBS) to create 3D models from DICOM image format. After that the computer program designed template (designed based on the image data of individual patient) it is put to print by using the latest technologies for 3D engraving. CAST is therefore plastic guidance, designed to meet the needs of individual operational approach and is at the same time an ideal fit to the patient's specific anatomy of the bones. The piece is designed to contain holes or notches through which the surgeon carefully conducts drilling or sawing of the bone, which is a great advantage over standard techniques, providing greater accuracy and minimizing the potential errors due to human factors. Due to pre-operational planning process use of x-ray radiation is significantly reduced during the surgery.