This invention relates to a method for operating on a spine, and more particularly to a method for operating on a spine by using a spinal fixation device which comprises the steps of (1) creating a hole on a vertebra (2) placing said hollow fixation part joined with said cover part into the hole, and leaving the joining end of said hollow fixation part outside of the vertebra and exposed (3) injecting said medical filling into said cover part via an injecting device and said hollow fixation part (4) allowing said medical filling to become solidified so that said medical filling and the cover part form a lump (5) removing said injecting device from said hollow fixation part.
