Medical instrumentation includes two or, in particular, more anchoring elements for anchoring on body tissue, and a stabilization element via which the two or more anchoring elements are connectable. The instrumentation includes a sensor unit, a coupling unit for percutaneous selective coupling of the sensor unit to at least one anchoring element or to the stabilization element, and a data processing unit which determines from sensor signals of the sensor unit the position of the anchoring elements relative to one another and/or the position of at least one anchoring element relative to the stabilization element.