Correction loss following short-segment posterior fixation for traumatic thoracolumbar burst fractures related to endplate and intervertebral disc destruction

BackgroundThere has been widespread use of short-segment posterior fixation (SSPF) for traumatic thoracolumbar burst fractures. The relationship between the destruction of the vertebral endplate and adjacent disc and postoperative correction loss has been studied in only a few studies. This study investigated the risk factors for correction loss following SSPF.MethodsForty-eight patients (mean age 35.0 years) who underwent SSPF for thoracolumbar burst fractures were enrolled. The mean follow-up period was 25.7 months (12-98 months). The neurological status and postoperative back pain were assessed by the medical records. Segmental kyphotic angle (SKA) and anterior vertebral body height ratio (AVBHR) were measured radiographically to assess indirect vertebral body reduction and local kyphosis. Preoperative Sander's traumatic intervertebral disc lesion (TIDL) classification and AO classification were used to evaluate the severity of disc and vertebral endplate injury. The corrective loss was considered present if Delta SKA was >= 10 degrees. A multivariate logistic regression analysis was performed to identify the risk factors associated with postoperative loss of correction.ResultsThe fracture distribution was as follows: 10 at T12, 17 at L1, 10 at L2, 9 at L3, and 2 at L4. Vertebral fractures were classified in the following way: A3 in 13 patients, A4 in 11, B1 in 11, and B2 in 13. In 47 patients (98%), a union of the fractured vertebrae was achieved. SKA and AVBHR improved significantly after surgery from 11.6 degrees to 3.5 degrees and from 67.2 to 90.0%, respectively. However, the correction loss at follow-up was 10.4 degrees and 9.7%, respectively. Twenty patients (42%) had severe TIDL (grade 3). Postoperative Delta SKA and Delta AVBHR were significantly higher in patients with TIDL grade 3 than with TIDL grade 0-2. The presence of cranial TIDL grade 3 and older age were significant risk factors for Delta SKA >= 10 degrees on multivariate logistic regression analysis. All patients could walk at follow-up. TIDL grade 3 and Delta SKA >= 10 degrees were associated with severe postoperative back pain.ConclusionsRisk factors for loss of correction after SSPF for thoracolumbar burst fractures were severe disc and endplate destruction at the time of injury and older age.