An undercutting system for preparing a region between an ilium and a sacrum for sacroiliac fusion. The undercutting system includes a probe assembly and a cutting assembly. The probe assembly is operably mounted to the insertion apparatus. The probe assembly is moveable with respect to the insertion apparatus between a retracted configuration and an extended configuration. In the extended configuration at least a portion of the probe assembly extends laterally from the insertion apparatus. The cutting assembly is operably mounted with respect to the probe assembly and the insertion apparatus. The cutting assembly is movable with respect to the insertion apparatus between a retracted configuration and an extended configuration. In the extended configuration at least a portion of the cutting assembly extends laterally from the insertion apparatus.