Traumatic Posterior L4–L5 Fracture Dislocation of the Lumbar Spine: A Case Report

摘要

Study Design Case report. Objective The diagnosis and surgical management of a patient with traumatic bilateral posterior dislocation of L4–L5 is presented with a thorough review of the existing literature. Summary of Background Data Traumatic dislocation of L4–L5 has been reported in the English literature in only five cases; of these, only two were retrolisthesis. Methods A 20-year-old patient was involved in a high-energy vehicular accident and presented with back pain and inability to ambulate. Neurological assessment showed motor strength grade 2/5 in the proximal lower-extremity muscle groups (L1–L3 myotomes) and 0/5 strength distally (L4–S1 myotomes); in addition, incontinence of sphincters was found. X-rays and computed tomography (CT) scan revealed a three-column ligamentous injury with posterior fracture-dislocation of the L4 vertebral body with complete posterior displacement of L4 to L5 vertebral body. The patient underwent posterior approach with reduction, transpedicular fixation, and posterolateral fusion with autologous bone graft. Results At 1-year follow-up, the patient had recovered muscular strength in proximal lower-extremities muscle groups, sphincter function had fully recovered, and he was able to ambulate with crutches. There was no recovery of distal extremity sensorimotor function. Plain radiograph and CT scan showed good alignment and progressive maturation of his fusion procedure. Conclusion Traumatic retrolisthesis of L4–L5 is a high-energy unstable fracture; reduction of the dislocation is challenging because of the heavy forces acting in the lower lumbar spine. Instrumented fusion restores alignment and maintains segmental stability. Keywords: thoracolumbar trauma, traumatic retrolisthesis, fracture-dislocation Traumatic spondyloptosis, or grade 5 spondylolisthesis, is defined as greater than 100% traumatic subluxation of one vertebral body in the coronal or sagittal plane. 1 Traumatic L5–S1 dislocation had been frequently reported 2 3 4 5 ; on the other hand, there are few reports about traumatic dislocation of L4–L5. Only five cases are reported in the English literature, 6 two of which were retrolisthesis. 7 8 We report one case of L4–L5 traumatic posterior dislocation of L4 vertebral body caused by high-energy trauma. Both the L4 vertebral body and the vertebral column above were totally displaced posterior to the L5 vertebral body. The mechanism of injury, surgical management, and 1-year follow-up are evaluated.