This equipment comprises at least one connecting bar and at least one sacrum anchor assembly (1-3, 5). According to the invention, each sacrum anchor assembly comprises two sacral anchor screws (1,2), a link assembly (3) including: a sacral connecting part (10) assembled to a sacral anchor plate (11) with polyaxiality, i.e. having possible multi-directional tilting relative to the said first screw (1), and possible pivot relative to the said sacral anchor plate (11) two nuts (5) able to be screwed onto the said shanks (9) of the said first and second screws (1, 2), a first nut (5) is able to clamp this part (10) against a bearing surface (8) formed in the said first screw (1), for tilt and pivot immobilisation of this part (10) relative to the said sacral anchor plate (11).
