The invention relates to a method for constructing a patient-specific surgical guide comprising at least one contact element comprising a contact surface intended to match an anatomical structure to be treated and at least one guiding element for guiding a surgical instrument to treat said anatomical structure, said method comprising: —receiving a 3D medical image of the anatomical structure of the patient; —determining, in said 3D medical image, at least one region of interest containing a portion of the external surface of the anatomical structure intended to match a respective contact element of the surgical guide; —segmenting the 3D medical image in said determined region of interest so as to locally reconstruct the external surface of the anatomical structure; —computing the contact surface of the contact element from said reconstructed local surface of the anatomical structure; —constructing the at least one contact element to include the contact surface. —defining the position of the at least one guiding element with respect to the anatomical structure; —constructing the surgical guide by generating a rigid body including the at least one guiding element and said at least one contact element.