Enhanced spine fixation apparatus

A spine fixation apparatus, comprising:

• a connecting rod;
• a plurality of coupling blocks each having a lower side surface and an upper side surface;
• a plurality of pedicel screws each being anchorable in a vertebra;
• a plurality of first securing elements each for securing the coupling blocks on the pedicel screws respectively;
• a plurality of second securing elements each for securing the connecting rod on each of the coupling blocks;
• and
• a plurality of third securing elements each having an engaging end surface for engaging with each of the first securing elements;
• wherein, each of the pedicel screws includes a first head portion having a first spherical convex surface at a top end surface thereof, and a first engaging hole longitudinally extending substantially along a longitudinal axis of each of the screws and opening to the first convex surface;
• each of the first securing elements includes:
• a shank portion to be detachably secured in the first engaging hole of the pedicel screw;
• and
• a second head portion having a second spherical convex surface disposed at a top of the shank portion;
• and
• each of the coupling blocks includes:
• a first socket for the shank portion of the first securing element passing therethrough, in which the first socket includes a first recess opening to the lower side surface and defined by a first concave surface for accommodating and matching with at least a portion of the first head portion, a second recess opening toward the upper side surface and defined by a second concave surface for accommodating and matching with the second head portion with a spacing left between portions of the second spherical convex surface and the second concave surface, and an aperture extending between and opening to the bottoms of the first and the second recesses and having a diameter larger than that of the shank portion and smaller than a largest diameter at either of the first and the second head portions;
• a second socket substantially axially perpendicular to the first socket, for the connecting rod accommodated therein;
• a second engaging hole substantially axially perpendicular to the second socket for securing the connecting rod in cooperation with the second securing element;
• and
• a third engaging hole communicating with the second recess and opening to the upper side surface of the coupling block for engaging with the third securing element so that the engaging end surface of the third securing element forces the first securing element against the coupling block.