Thoracolumbar Burst Fracture: McCormack Load-Sharing Classification - Systematic Review and Single Arm meta-Analysis.

STUDY DESIGN A systematic review and single-arm meta-analysis of randomized clinical trials. OBJECTIVE To evaluate if the load-sharing classification (LSC) is reliable to predict the best surgical approach for thoracolumbar burst fracture (TBF). SUMMARY OF BACKGROUND DATA There is no previous review evaluating the efficacy of the use of LSC as a guide in the surgical treatment of burst fractures. METHODS On April 19, 2019, a broad search was performed in the following databases: EMBASE, PubMed, Cochrane, SCOPUS, Web of Science, LILACS, and grey literature. This study was registered on the International Prospective Register of Systematic Reviews. We included clinical trials involving patients with TBF undergoing posterior surgical treatment, classified by load-sharing score, and that enabled the analysis of the outcomes loss of segmental kyphosis and implant failure. We performed random or fixed effects models meta-analyses depending on the data homogeneity. Heterogeneity between studies was estimated by I and τ statistics. RESULTS The search identified 189 references, out of which nine studies were eligible for this review. All papers presenting LSC up to 6 proved to be reliable in indicating that only posterior instrumentation is necessary, without screw failures or loss of kyphosis correction. For cases where the LSC was higher than 6, only 2.5% of the individuals presented implant failure upon posterior approach alone. For loss of kyphosis correction, only 5% of patients had this outcome where LSC > 6. For both outcomes together, we had 6% of postoperative problems (I = 77%, τ < 0.0015, p < 0.01). CONCLUSION Load-sharing scores up to 6 are 100% reliable, only requiring posterior instrumentation for stabilization. For scores higher than 6, the risk of implant breakage and loss of kyphosis correction in posterior fixation alone is low. Thus, other factors should be considered to define the best surgical approach to be adopted. LEVEL OF EVIDENCE 1.