A plurality of expandable fixation devices (EFDs) for minimally invasive surgery. The EFDs use an expanding deformation of the device to achieve a mechanical interference with the environment, e.g., bone. The shape of expansion can be controlled by many factors including the original geometry of the part, the geometry of material removed from the part, and the amount of deformation applied to the part. The EFD may be a relatively large anchor-type fixation device generally characterized by a single set of long longitudinal cuts parallel to a central axis of the device or concentric to a central curve of the device. The EFD may alternatively be a relatively small anchor-type fixation device generally characterized by multiple sets of shorter longitudinal cuts parallel to a central axis of the device or concentric to a central curve of the device. The EFD may also be a screw-type fixation device generally characterized by multiple rotationally indexed cuts in a helical pattern. The cuts define intermediate material regions which form protrusions on the EFD when deformed and, taken together, form a non-continuous helical thread to anchor the EFD in a bone.