This is a very small woman with severe degenerative changes and instabilty at the L23 level. She is recently retired, in her mid 60's, and a longtime smoker - who only recently quit. Following lateral interbody fusion, posterior pedicle screw instrumentation was used. The pedicle measured 5.5 mm and a 5.5 mm screw was placed. The screw fills the pedicle completely with good purchase. The non-threaded portion of the pedicle screws are properly positioned facing the neurological structures. The screws may well penetrate the medial wall of the pedicle. The dotted lines demonstrate the level of encroachment which would be added were the screw fully threaded. She has obtained a solid fusion without the development of any radicular symptoms. The modified screw allows the surgeon to optimize the diameter of the fixation screw.