Operative Treatment of Thoracolumbar Burst Fractures: Is Fusion Necessary?

Abstract

Burst fractures of the thoracolumbar junction and upper lumbar spine (T12–L2) are common injuries as a result of high-energy trauma, with potentially devastating consequences including pain, paralysis, and loss of function [8]. The thoracolumbar junction, especially, is highly susceptible to injury as it is a fulcrum for increased motion between the rigid thoracic spine and mobile lumbar spine. Burst fractures can often result in significant spinal instability requiring operative stabilization. The classification and treatment of these injuries are controversial. Historic surgical indications based on kyphosis, canal compromise, and loss of vertebral body height failed to accurately reflect the dynamic mechanism of the injury and neglected the neurologic status of the patient. The most commonly used classification today is the thoracolumbar injury classification and severity score (TLICS) described by Vaccaro et al. [5], which includes the morphology of the fracture pattern, the integrity of the posterior ligamentous complex (PLC), and the patient’s neurologic status. While these classification systems are invaluable in indicating patients for surgery as well as guiding the surgical approach, one particular area of controversy is whether fusion is necessary to achieve a good clinical outcome after fixation of thoracolumbar or lumbar burst fractures. There have been several prospective trials comparing patients treated with posterior short segment instrumentation for thoracolumbar and lumbar burst fractures, randomized to fusion or no fusion, with largely similar outcomes [1, 6]. The article discussed here, by Chou et al., describes the long-term follow-up on their randomized cohort, with a mean follow-up of 134 months. In this randomized trial of 46 patients with thoracolumbar or lumbar burst fractures treated with posterior instrumentation with or without fusion, their specific research question was, What are the differences in functional, radiographic, and hardware removal or complication rates between the fusion and non-fusion groups? The purpose of this review is to interpret the outcomes of this study, in which the patients were enrolled and the procedures performed more than 10 years ago, in the context of our now improved understanding of the factors contributing to instability in burst fractures and an evolution in the indications for surgical intervention. Are the conclusions of this randomized trial still valid today? The Article Fusion May Not Be a Necessary Procedure for Surgically Treated Burst Fractures of the Thoracolumbar and Lumbar Spine: A Follow-up of at Least Ten Years Po-Hsin Chou, Hsiao-Li Ma, Shih-Tien Wang, Chien-Lin Liu, Ming-Chau Chang, Wing-Kwong Yu JBJS 2014;96:1724-31 October 15. The main research question was, for thoracolumbar and lumbar burst fractures treated with posterior instrumentation, is fusion necessary? The investigators performed a randomized trial in 46 patients treated with posterior transpedicular screw fixation to the levels above and below the injury, with or without fusion. This was a single-surgeon cohort in Taipei, Taiwan. Fifty-eight patients with burst fractures were enrolled from 1996–2003. Inclusion criteria was any neurologic deficit or no deficit but kyphosis >20°, decreased vertebral body height >50%, and canal compromise >50%. Patients requiring anterior surgery were excluded. Ten patients were lost to follow-up and two excluded based on age. The final cohort of 46 patients had a mean age of 39.4 at the time of injury. The fractures were all from T12–L2, with 24% Denis type A and 76% type B. Outcome measures included radiographic (kyphosis, vertebral height, regional segmental motion, adjacent listhesis, appearance of callus), functional (VAS, low-back outcome score), and hardware removal or breakage. At mean follow-up of 134 months, there was no difference at all time points between the fusion and non-fusion groups in kyphosis or vertebral height. Both groups had significant loss of kyphosis correction over time (10.7° vs. 12.3°, respectively). Regional segmental motion was 0.9° in the fusion group and 4.2° in the non-fusion group (p < 0.05). Functional outcomes were statistically similar at all time points. The authors concluded that the long-term outcomes of short-segment fixation for thoracolumbar and lumbar burst fractures with and without fusion are comparable.