The present invention relates to an image-based, patient-specific medical spinal surgery technique and to a spinal prosthesis used in the surgery, and particularly, to an image-based, patient-specific medical spinal surgery technique and to a spinal prosthesis which are intended to solve a problem of damage to a spine caused by installing a spinal prosthesis used in spinal surgery, by introducing an image of a patient to manufacture an insertable spinal prosthesis that is customized for a shape of a spine of an individual patient in a polymer-based material.