A percutaneous and minimally invasive instrument for inserting an interspinous process spacer into a patient is disclosed. The instrument includes a first assembly connected to a handle assembly. The first assembly includes an inner shaft located inside an outer shaft and configured for translational motion with respect to the outer shaft. The relative translational motion causes one of the outer or inner shafts to move with respect to the other and thereby deflect at least one prong formed on one of the inner or outer shafts wherein such deflection causes engagement with a juxtapositioned interspinous spacer. The instrument further includes a driver configured for removable insertion into a proximal end of a passageway of the instrument. The driver has a distal spacer engaging portion configured to engage that part of the spacer requiring activation for deployment of the spacer from an undeployed configuration to a deployed configuration and vice versa.
