Customised surgical apparatus

#This application is a National Stage 35 U.S.C. 371 of International Patent Application PCT/GB2009/0000517 filed Feb. 26, 2009, which claims benefit of priority of United Kingdom Application No. GB 0803514.9, filed Feb. 27, 2008 (now abandoned).

#The present invention relates to customising surgical apparatus and in particular to customising surgical instruments and/or implants using patient specific data obtained from a captured image of a patient.

#The general idea of creating a patient specific instruments or implants from CT or MRI data has been described previously, for example in U.S. Pat. No. 5,768,134 and WO 93/25157. U.S. Pat. No. 5,768,134 describes using a CT scanner or MRI scanner to generate digitized medical information, which can be used with additional digital information, and a rapid prototyping method to create a prosthesis matching a body part and to which a further functional element can be attached. WO 93/25157 describes a method using tomographic data, such as from a CT or MRI scan, and image processing to generate a 3D reconstruction of the body part, which can be used with a CNC machine to allow an individual prostheses to be created. An individual template can also be manufactured matching a patient's anatomy and for mounting on the patient for guidance, alignment and positioning of a treatment tool.

#An embodiment of the invention will now be described in detail, by way of example only, and with reference to the accompanying drawings, in which:

#FIG. 1 shows a schematic flow chart illustrating the process of designing a customised instrument;

#FIG. 2 shows a schematic flow chart illustrating the building and use of a statistical shape model;

#The present invention uses one or more x-ray images, combined with a statistical model, to provide patient specific anatomy of a joint, or other body part, which can be used to design and manufacture a customised instrument to be used in an orthopaedic procedure on the joint, or to design and manufacture a customised prosthesis for the patient.

#In the case of carrying out a surgical procedure of a knee joint, the mechanical axis of the femur and tibia can be calculated from one or more x-ray images of the hip joint and ankle joint, which are referenced into the co-ordinate frame of the x-rays taken of the knee joint and by taking appropriate measurements from the images.

#The design of a custom instrument and/or prosthesis can be fully automated by incorporating the features of the bony anatomy and relevant soft tissues relevant for planning into the statistical model.