A surgical instrument comprising: a body configured to receive a fastener, the body defining a cavity configured to receive a head of the fastener when the fastener is disposed in the body, the cavity having an inwardly extending flange defining a proximal opening of the cavity; a fastener having a threaded portion and a head portion, the head portion comprising: an upper socket configured to interface with a driver for adjusting the position of the fastener within the body; characterized in that, the instrument further comprises: a lower socket; and at least one channel radially extending from the lower socket and sized and shaped to allow translation of a locking body through the channel; and a locking body disposed in each of the at least one radially extending channels of the fastener, wherein the surgical instrument has a first configuration when the head portion of the fastener is engaged by a first driver and a second configuration when the head portion of the fastener is engaged by a second driver, wherein, in the first configuration, engagement of a drive portion of the first driver with the upper socket of the head portion allows the locking body to move radially inward in the channel such that the fastener can be inserted distally into the body and removed proximally from the body without interference between the locking body and the flange of the cavity, and wherein, in the second configuration, when the fastener is disposed in the body such that the at least one radially extending channel is disposed distal to the flange of the cavity, engagement of a drive portion of a second driver with the upper socket includes engagement of a distal end portion of the second driver with the lower socket of the head portion that displaces the locking body radially outward such that the locking body interferes with the flange of the channel when the fastener is advanced proximally by the second driver such that the fastener cannot be removed from the body by the second driver. a body configured to receive a fastener, the body defining a cavity configured to receive a head of the fastener when the fastener is disposed in the body, the cavity having an inwardly extending flange defining a proximal opening of the cavity; a fastener having a threaded portion and a head portion, the head portion comprising: an upper socket configured to interface with a driver for adjusting the position of the fastener within the body; characterized in that, the instrument further comprises: a lower socket; and at least one channel radially extending from the lower socket and sized and shaped to allow translation of a locking body through the channel; and an upper socket configured to interface with a driver for adjusting the position of the fastener within the body; characterized in that, the instrument further comprises: a lower socket; and at least one channel radially extending from the lower socket and sized and shaped to allow translation of a locking body through the channel; and a lower socket; and at least one channel radially extending from the lower socket and sized and shaped to allow translation of a locking body through the channel; and a locking body disposed in each of the at least one radially extending channels of the fastener, wherein the surgical instrument has a first configuration when the head portion of the fastener is engaged by a first driver and a second configuration when the head portion of the fastener is engaged by a second driver, wherein, in the first configuration, engagement of a drive portion of the first driver with the upper socket of the head portion allows the locking body to move radially inward in the channel such that the fastener can be inserted distally into the body and removed proximally from the body without interference between the locking body and the flange of the cavity, and wherein, in the second configuration, when the fastener is disposed in the body such that the at least one radially extending channel is disposed distal to the flange of the cavity, engagement of a drive portion of a second driver with the upper socket includes engagement of a distal end portion of the second driver with the lower socket of the head portion that displaces the locking body radially outward such that the locking body interferes with the flange of the channel when the fastener is advanced proximally by the second driver such that the fastener cannot be removed from the body by the second driver.