A driver assembly for affixing a surgical fastener to a target location is provided. Operation of the driver assembly inserts the surgical fastener in two stages, first an alignment stage through application of a distally directed force to partially insert the surgical fastener, and then a fastening stage to fully insert and seat the surgical fastener to a proper depth or compression level. The driver assembly comprises a spring loaded automatic trigger mechanism that may be adapted for use with a linearly insertable or a rotationally insertable surgical fastener. Application of the distally directed force actuates the trigger mechanism, wherein a corresponding impact force is delivered for seating the surgical fastener, coupled to a distal end of the driver assembly, upon alignment of cam and receiver elements embodied within the trigger mechanism.
