Burst fracture of the fifth lumbar vertebra.

Burst fracture of the fifth lumbar vertebra is a rare injury. We report the cases of seven patients who were treated conservatively by immobilization for six to eight weeks in a body-jacket cast that included one lower extremity to the knee. The patients were allowed to walk ten to fourteen days after the injury. A thoracolumbosacral orthosis was worn for an additional three months. No patient had an injury to the sacral root. Two patients had mild lower lumbar motor-root deficits that resolved within one year. All patients had an occasional backache, and two had intermittent radicular-type pain in the distribution of the fifth lumbar or first sacral-nerve root. The degree of compromise of the spinal canal could not be directly related to the degree of neurological deficit; that is, a large compromise of the spinal canal did not necessarily result in a major loss of neurological function. There was no early or late loss of lordosis between the cephalad end-plate of the fourth lumbar vertebra and the cephalad aspect of the sacrum, and there were no signs of progressive collapse of the vertebral body in any patient. In our series, the burst fractures of the fifth lumbar vertebra were stable injuries that caused minimum neurological deficits, and treatment by immobilization in a body-jacket cast was effective.