Abstract: The present invention relates to a bone screw comprising a screw body comprising a proximal end, a distal end, a longitudinal axis and a thread along all or a portion of said screw body; a screw head; a through bore extending coaxially through said screw head and through said screw body from the proximal end up to the distal end; at least three blind channels angularly-disposed around the bore; each of said channels being configured to receive a perforated catheter or a needle; a plurality of radially-disposed fenestrations; wherein each of said channels is connected to an exterior of said screw body through at least one fenestration; and flexible directing means secured to the screw head. The present invention also relates to a system comprising such bone screw, to a method of delivering a substance to an intervertebral disc using the system according to the invention and to a method of treating vertebral tumor using the system according to the invention.