The solid phase epitaxial regrowth of structurally modified amorphous silicon created by self-ion implantation into nanovoided crystalline silicon is investigated. It is demonstrated that although the modified amorphous silicon is fully reconstructed into single crystal during the epitaxial regrowth, both activation energy and atom attempt frequency for the regrowth are much higher than those of the typical amorphous Si induced by self-ion implantation into Si wafer without nanovoids. The novel regrowth kinetics indicates that the modified amorphous silicon would contain a very high concentration of dangling bonds, which are believed to result from dissociation of the nanovoids originally metastablized in crystalline silicon. The unparalleled sensitivity of SPEG provides an effective and simple way to detect and characterize the subtle structural changes at nanometer scale in amorphous Si.