Sacral Insufficiency Fracture: An Insidious Cause for Low Back Pain.

A 79-year-old woman was seen due to low back pain and severe right hip pain. The pain was radiating to the right calf. The patient reported numbness of her right ankle and toes. On detailed questioning, she reported that her hip pain worsened with sitting and walking. She stated that her hip pain improved when lying supine. Her medical history revealed hypertension and osteomalacia, but no trauma. On physical examination, low back flexion and extension were painful at the end of range of motion testing. Neurological examination was normal except for hypoesthesia along the right L5 dermatome. Visual analog scale (VAS) pain score was 8/10. Bone mineral density measurements revealed osteoporosis (T-scores of femoral neck and L1-4 vertebra were -2.7 and -1.4, respectively). Laboratory investigations yielded decreased levels of total calcium, phosphorous, and 25-hydroxyvitamin D, in addition to elevated values of alkaline phosphatase, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and parathormone. Lumbosacral anteroposterior radiograph showed severe degeneration in all lumbar vertebrae, L5-S1 spondylolisthesis, decreased T12-L2 vertebral body height,