Sacral insufficiency fracture is a rare complication of the lumbar spinal surgery. It is normally reported as a late complication of the multi-segment spinal fixation in females with osteoporotic bone. We present the case of an elderly gentleman who suffered this complication spontaneously on the second postoperative day. To the best of our knowledge this has never been reported in Pakistan. Sacral alae are directly in line with weight bearingwhile walking and should be kept in mind when mobilizing a postoperative patient whose previous history indicates such risk factors. Once injury is suspected, CT scan is recommended as x-rays may not always reveal the injury. In literature, these fractures have almost always been treated conservatively.1 Conservative management wasnot tolerated well in our case and we proceeded with surgical management using S2 sacral alar iliac screws (S2 AI screws) to extend the previous lumbosacral fusion construct. S2 AI screws are a novel technique used for bone lumbosacral fusion and studies have shown to have lower rate of screw breakage under stress and need for revision surgery with their use.