A rongeur (34) for driving a cutting unit (240) that includes an outer (240) tube and a cutting implement (302) able to both rotate in move longitudinally in the outer tube The rongeur includes a body (36) to which a rotating spindle (102) for actuating the cutting implement is mounted. The spindle is designed to allow the inner tube to while, rotating move longitudinally relative to the spindle. A mechanism (150, 180) attached to the body selectively displaces the drive inner tube so the distal end of the cutting implement can be advanced towards and retracted away from the distal end of the outer tube.
