LAUSR

Rationale: Albeit it is rare, the authors report a stage 3 Kummell disease case. It is diagnosed by dynamic thoracic magnetic resonance imaging (MRI). Because there is no established strategy on stage 3 Kummell disease, we performed percutaneous kyphoplasty at first, but unfortunately made a revision surgery to remove the polymethylmethacrylate (PMMA) cement after the failure of percutaneous kyphoplasty. Patient concerns: A 73-year-old lady with severe back pain due to osteoporosis vertebral fracture was admitted to our hospital on June 23, 2016. She underwent percutaneous kyphoplasty with the back pain improved shortly. Unfortunately, she went back to our hospital due to aggravated back pain and partial paralysis on July 25, 2016. Diagnoses: Kummell disease, lumbar stenosis, lacunar infarction. Outcomes: Specially, the compression of spinal cord was obvious in the hyperflexion position on dynamic MRI. Even though there was no improvement in muscle strength, the patient was satisfied with the back pain relief after percutaneous kyphoplasty. But, the same back pain reappeared after about 1 month. Then, we took out the PMMA cement and performed posterior vertebral column resection. At last, the back pain was relieved again but the muscle strength was improved not obviously after operation. At the same time, the kyphosis was corrected and the intravertebral stability was achieved. Lessons: Dynamic MRI is helpful in Kummell disease with neurologic symptoms, even if there is no obvious compression in the neutral position. Furthermore, the intravertebral instability is probably the main reason of the neurologic symptoms in this case. Percutaneous kyphoplasty could not reconstruct the intravertebral stability. Stage 3 Kummell disease with obvious intravertebral instability should be treated by open surgery.