Surgical positioning apparatus

Methods and apparatus for positioning a surgical implement relative to a feature of a patient are disclosed. A method according to the invention comprises the steps of determining a required position of the implement relative to the feature, holding the required position in a processing means, producing data for the determination of an actual position of the implement, passing the data to the processing means and using the processing means to generate information for positioning the implement at the required position. A suitable exemplary apparatus for carrying out the above method comprises an x-ray unit 10, a mechanical arm 12 for holding the implement, and at least two infra-red cameras 14 which work in conjunction with infra-red emitters 30 on the x-ray unit 10 and mechanical arm. The x-ray unit 10, mechanical arm 12 and cameras 14 all pass information to a processor 16.