INSTRUMENT FOR ATTACHING TO A BONE ANCHOR AND INSTRUMENT FOR USE IN DISTRACTION AND/OR RETRACTION, IN PARTICULAR FOR ORTHOPEDIC SURGERY OR NEUROSURGERY, MORE SPECIFICALLY FOR SPINAL SURGERY
An instrument configured to attach to a bone anchoring element during surgery includes an elongate portion and an end portion having a first side and an opposite second side, where the elongate portion extends away from the first side, and where an opening is defined at the second side to accommodate at least a portion of a head of the bone anchoring element. The opening of the end portion has a first section sized to permit insertion and removal of the head therethrough, and a second section forming a seat for the head. When the head is held in the seat, the seat prevents removal of the head through the opening, while the head is movable unobstructedly from the second section back towards the first section.