Implanted Device Motion and Migration

Motion and migration (motion relative to an external reference frame) of implanted medical devices within the patient are important considerations in the design and development of this lifesaving technology. Implanted devices frequently translate and rotate (experience motion) due to cyclic organ motion, tissue growth or degradation, or activities of daily living to name a few. The case studies presented in this chapter as well as the discussion of cyclic motion in the “ Measuring Motion Cycle counts Within a Patient Population ” chapter introduce the concept of device motion. Device migration can occur due to several factors including but not limited to loss of fixation, incorrect sizing in the case of stents and heart valves, flow and pressure effects, tissue growth, patient motion, delivery system retrieval errors, or component failure. Potential complications are varied including pain, loss of therapeutic function, the need for secondary intervention or placement of another device, or in some cases patient mortality.