Predisposing Factors for Intraoperative Endplate Injury of Extreme Lateral Interbody Fusion

STUDY DESIGN Retrospective study. PURPOSE To compare intraoperative endplate injury cases and no injury cases in consecutive series and to identify predisposing factors for intraoperative endplate injury. OVERVIEW OF LITERATURE Unintended endplate violation and subsequent cage subsidence is an intraoperative complication of extreme lateral interbody fusion (XLIF). It is still unknown whether it is derived from inexperienced surgical technique or patients' inherent problems. METHODS Consecutive patients (n=102; mean age, 69.0±0.8 years) underwent XLIF at 201 levels at a single institute. Preoperative and immediately postoperative radiographs were compared and cases with intraoperative endplate injury were identified. Various parameters were reviewed in each patient and compared between the injury and no injury groups. RESULTS Twenty one levels (10.4%) had signs of intraoperative endplate injury. The injury group had a significantly higher rate of females (p=0.002), lower bone mineral density (BMD) (p=0.02), higher rate of polyetheretherketone as cage material (p=0.04), and taller cage height (p=0.03) compared with the no injury group. Multivariate analysis indicated that a T-score of BMD as a negative (odds ratio, 0.52; 95% confidence interval, 0.27-0.93; p=0.03) and cage height as a positive (odds ratio, 1.84; 95% confidence interval, 1.01-3.17; p=0.03) were predisposing factors for intraoperative endplate injury. CONCLUSIONS Intraoperative endplate injury is correlated significantly with reduced BMD and taller cage height. Precise evaluation of bone quality and treatment for osteoporosis might be important and care should be taken not to choose excessively taller cage.