Abstract: Disclosed is an extension piece at a screw end of a pedicle screw, where two extension pieces are oppositely disposed at the pedicle screw tail, and the extension pieces are flexible extension pieces. The extension pieces are flexibly designed, having elastically bendable characteristics, the extension pieces in the subcutaneous part can be elastically bent by external force, its dilation trend may not extend to the epithelial part, and it is feasible that muscles are squeezed only subcutaneously, so as to keep small incisions, and in the case of a threading operation of a reset rod, as portions of the two extension pieces in the subcutaneous part are dilated and separated after bending, a sufficient threading space can be provided, so that the threading operation is easy to perform, thereby reducing risks of surgeries. Further disclosed are a dilator and a push rod reset lever cooperating with the extension piece.