A fusion system (500, 600) for insertion within a patient's vertebrae, comprising: a first fastener (510, 610) comprising a first head (514, 614) with a first slot (522, 620), a first shaft (512, 612) and a first neck (516, 616) coupling the first head (514, 614) to the first shaft (512, 612), and wherein the first head (514, 614) comprises a body portion (518, 520, 618) defining an interior surface and a top surface, and a first base (524, 622) extending below the body portion (518, 520, 618) defining a concave interior surface, and wherein the first slot (522, 620) extends through the body portion (518, 520, 618) from the top surface thereof and through a first portion of the first base (524, 622) to a bottom of the concave interior surface; a second fastener (530, 630) comprising a second head (534, 634) with a second slot (542, 640), a second shaft (532, 632) and a second neck (536, 636) coupling the second head (534, 634) to the second shaft (532, 632), and wherein the second head (534, 634) comprises a body portion (538, 540, 638) defining an interior surface and a top surface, and a second base extending below the body portion (538, 540, 638) defining a concave interior surface, and wherein the second slot (542, 640) extends through the body portion (538, 540, 638) from the top surface thereof and through a first portion of the second base to a bottom of the concave interior surface; and an elongate member (550, 650) inserted into the first fastener (510, 610) at a first end and the second fastener (530, 630) at a second end, wherein the elongate member (550, 650) may be positioned at varying angulations with respect to the first and second fasteners (510, 530, 610, 630). a first fastener (510, 610) comprising a first head (514, 614) with a first slot (522, 620), a first shaft (512, 612) and a first neck (516, 616) coupling the first head (514, 614) to the first shaft (512, 612), and wherein the first head (514, 614) comprises a body portion (518, 520, 618) defining an interior surface and a top surface, and a first base (524, 622) extending below the body portion (518, 520, 618) defining a concave interior surface, and wherein the first slot (522, 620) extends through the body portion (518, 520, 618) from the top surface thereof and through a first portion of the first base (524, 622) to a bottom of the concave interior surface; a second fastener (530, 630) comprising a second head (534, 634) with a second slot (542, 640), a second shaft (532, 632) and a second neck (536, 636) coupling the second head (534, 634) to the second shaft (532, 632), and wherein the second head (534, 634) comprises a body portion (538, 540, 638) defining an interior surface and a top surface, and a second base extending below the body portion (538, 540, 638) defining a concave interior surface, and wherein the second slot (542, 640) extends through the body portion (538, 540, 638) from the top surface thereof and through a first portion of the second base to a bottom of the concave interior surface; and an elongate member (550, 650) inserted into the first fastener (510, 610) at a first end and the second fastener (530, 630) at a second end, wherein the elongate member (550, 650) may be positioned at varying angulations with respect to the first and second fasteners (510, 530, 610, 630).