Complete fracture-dislocation of the lower lumbar spine with spontaneous neurologic decompression.

Complete posterior fracture-dislocation of the lumbar spine at L4-L5 level occurred in an 18-year-old male patient, who remained neurologically intact. The body of L4 with the vertebral column above was totally displaced behind the body of L5. The posterior elements of L5 were fractured and displaced posteriorly with L4, and this led to marked widening of the canal with spontaneous neurologic decompression. Open reduction and internal fixation with a sacral rod and two Harrington rods restored the anatomic relationship. In spite of the good reduction immediately obtained after surgery, two months later the fracture showed some redisplacement. The implants were removed, and a bone graft was transplanted for additional support. Seven months after trauma, the patient is asymptomatic and the spine is solidly fused. In spite of the risk of neurologic deterioration involved during surgery, open reduction and internal fixation were performed because they offered the best chance of healing, producing a biomechanically sound spine, and decreasing the risk of delayed neurologic deterioration. Because of the relatively wide neural canal at the lumbar level and the absence of spinal cord from the neural elements at the level of the injury, the risk of permanent neurologic deficit being produced during surgery was considered minimal.