A Case of an Intraspinal Cystic Mass Due to Osteoporotic Compressed Vertebral Fracture at L1

Abstract

We experienced a rare case with conus medullaris syndrome caused by an intraspinal cystic mass derived from compressed vertebra. A 68 year old man suffered an L1 compressed fracture from falling. Two months later, he experienced severe lumbago after lifting something heavy. Then, he felt numbness in his buttocks and thighs after a few days, and this symptom became aggravated before he was finally referred to our center. On admission, he was also suffering intermittent claudication and had difficulty urinating. Plain radiographs showed a vertebral collapse at the L1 spine. MRI represented a large cystic lesion antero medial in the spinal canal strongly compressing the spinal cord at that level, of which the intensity was identical with that of fluid. A Myelogram showed the complete obstruction of contrast medium adjacent to the collapsed body of L1. The patient underwent laminectomy at the L1 level and microscopic resection of the cyst. The cyst wall had a surface covered with smooth and whitish tissue, but it didn't adhere to the dura. The fluid in the cyst was serous and yellowish. The cyst was reduced in size, followed by Th11 L3 transpedicular fixation combined with transpedicular focal bone and HA granule grafts at the L1 vertebra. The postoperative course was uneventful and the patient's neurological impairment soon disappeared completely. In this case, the sudden vertical load caused a comminuted burst of the L1 vertebral body. We suspect that the fluid inside the vertebral body extended posterior and formed a large intraspinal cystic mass, resulting in conus medullaris syndrome.