An end effector system for use in spinal surgery may be described herein. The end effector comprises a sterile section and a non-sterile section. The sterile section comprises an instrument holder that has pins for piercing a plastic sleeve. The instrument holder holds an instrument for performing spinal surgery. The non-sterile section comprises an end effector. The end effector comprises a motor and a transducer. The motor applies a torsional and axial force to the instrument. The transducer provides feedback to the end effector system to adjust a force applied to the instrument.