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

Background: Short-segment posterior fixation (SSPF) for traumatic thoracolumbar burst fractures has been widely used. Few studies have addressed the association between the destruction of the vertebral endplate and adjacent disc and postoperative correction loss. This study aimed to investigate the risk factors for correction loss after SSPF. Methods This study included 48 patients (mean age of 35.0 years) who underwent SSPF for thoracolumbar burst fracture. The mean postoperative follow-up period was 25.7 months (range, 12–98 months). Neurological status and postoperative back pain were assessed using medical records. The segmental kyphotic angle (SKA) and anterior vertebral body height ratio (AVBHR) were measured as radiographic parameters to evaluate the indirect reduction of the vertebral body and local kyphosis. The intervertebral disc and vertebral endplate injury severity were assessed using the preoperative Sander’s traumatic intervertebral disk lesions (TIDL) classification and AO classification. Correction loss was considered to be present if ΔSKA was ≥ 10°. Multivariate logistic regression analysis was performed to identify risk factors for postoperative correction loss. Results The distribution of fractures was as follows: 10 in T12, 17 in L1, 10 in L2, 9 in L3, and 2 in L4. Vertebral fractures were classified as follows: 13 patients had type A3, 11 had A4, 11 had B1, and 13 had B2. Union of the fractured vertebrae was achieved in 47 patients (98%). SKA and AVBH significantly improved after surgery from 11.6° to 3.5° and from 67.2–90.0%, respectively; however, correction loss at follow-up were 10.4° and 9.7%, respectively. Severe TIDL (Grade 3) was observed in 20 patients (42%). Patients with TIDL grade 3 showed significantly greater ΔSKA and ΔAVBHR after surgery than patients with TIDL grade 0–2. The multivariate logistic regression analysis revealed that the presence of cranial grade 3 TIDL and an older age were significant risk for ΔSKA ≥ 10°. All patients were able to walk at final follow-up. The postoperative severe back pain was associated with TIDL grade 3 and ΔSKA ≥ 10°. Conclusion Severe disc and endplate destruction at injury and older age are risk factors for correction loss following SSPF for thoracolumbar burst fractures.