The present invention is directed to a needle control handle which allows a needle extension distance to be adjusted, set and locked. In one embodiment, the control handle has an outer body and a piston adapted for relative longitudinal movement to extend the needle. A first control knob is movable on the piston for adjusting and setting the distance of the needle extension. A second knob is provided for releasably locking the first control knob on the piston once the needle extension distance has been set. Each of the knobs has a contact surface that enables the knobs to mutually lock with and release from each other.