Racial Differences in Iliac Crest Cancellous Bone Composition: Implications for Preoperative Planning in Spinal Fusion Procedures

Study Design: This was a retrospective cohort study. Objective: The objective of this study was to determine whether race, specifically American white and American black, correlates with the ratio of cancellous to total bone at the iliac crest. Summary of Background Data: Studies have demonstrated higher proximal femur bone density in American blacks than American whites. However, whether differences occur at the iliac crest, a common site for autologous graft material in spinal fusion surgery, is not well studied. Understanding such differences could aid orthopedic surgeon decision-making regarding graft options. Materials and Methods: A retrospective review was performed on 133 sequential patients ages 18-75 who underwent computed tomography scan of the pelvis, at a single academic medical center from January 1, 2014, to January 1, 2016. The cohort included 46 American white (21 females, 25 males) and 87 American black participants (40 females, 37 males), an average age of 51.8 years. Groups were matched regarding age, sex, body mass index, and Charlson Comorbidity Score. Measurements of cortical and cancellous bone thickness in the right and left iliac crests were performed using bone window protocol on computed tomography scans. Statistical significance was determined using a 2-tailed t test. Results: The interobserver interclass correlation coefficient reliability (N=2) for measurements at the right iliac crest is 0.895 (95% confidence interval, 0.852-0.925), and the interclass correlation coefficient for the left iliac crest is 0.912 (95% confidence interval, 0.877-0.938). A statistically significant difference in the mean cancellous bone ratio was found between American black (0.667±0.065) and American white (0.750±0.051) groups (P<0.001). Conclusions: At the iliac crest, American black patients had a lower mean ratio of cancellous to the total bone as compared with American white patients. This population may benefit from alternative graft options. While iliac crest autograft remains the first option for fusion surgeries, alternative options should be considered to ensure that each patient receives the best-personalized care.