A method for forming and abrading an implant void in a sacroiliac joint (“SI Joint”) without the use of a rotary cutting instrument. The method incorporates a multimodal abrading device having abrading surfaces on opposing sides and an open tip comprising a cutting edge. The method includes the step of using the abrading head to cut bone tissue from the SI Joint at an insertion point while simultaneously using the abrading surfaces to decorticate the cortical bone at the insertion point.