Lumbar burst fracture due to radiotherapy. Case report

The author experienced a case of lumbar burst fracture after radiotherapy. An 80-year-old man was the case. From around November 2016, he was conscious of his right lower limb pain without triggers and was admitted to the hospital with a diagnosis of an L5 vertebral burst fracture. He received radiotherapy for prostate cancer in 2014, and irradiation was thought to be the cause for the vertebral fracture. However, as differential diseases, a pathological fracture due to metastatic spinal tumor and a fracture due to osteoporosis were also suspected. Tumor marker was negative, and CT image, MRI image, and pathologic examination did not show findings suggesting malignancy. MRI image showed fluid sign in the L5 vertebral body, and CT image showed the roughening of bones mixed with bone translucency image and osteoporotic image that agreed with the irradiation field. So, it was diagnosed that the vertebral bone fracture occurred affected by irradiation. From L3 to the sacroiliac joint, posterior decompression fusion surgery was performed. After the surgery, deep infection occurred as a complication but calmed down. Six months after the operation, lower extremity pain became mild and crutch-walking became possible. (A.O.)