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Objective: The aim of this study is to investigate vertebral body bone mineral density (BMD) changes following posterolateral fusion with transpedicular screw fixation using quantitative computerized tomography (QCT) in short and relatively long-term periods., Patients and Methods: A retrospective study was performed to investigate vertebral body BMD changes in the patients who underwent posterolateral fusion with transpedicular screw fixation at thoracic and lumbar spine. A total of 160 patients were enrolled into the study. According to the follow-up period, patients were divided into two subgroups (group 1, early follow-up, mean follow-up period, 279.3±162.3 days and group 2, later follow-up, mean follow-up period, 969.1±274.2 days). The trabecular BMDs (mg/cm³) were measured from T12 to L5 as screw free levels by using QCT measurement software. Comparisons between preoperative and postoperative BMD values were assessed using paired t-test., Results: The mean postoperative BMD values of both group 1 and 2 weresignificantly lower, compared with the preoperative values (79.2±31.3mg/cm³ vs. 91.5±31.4mg/cm(3), 76.1±25.5mg/cm(3) vs. 89.3±30.4mg/cm(3), p<0.001 and p<0.001, respectively). There was no significant correlation between BMD loss and number of fused segments. Vertebral BMD loss was significantly higher in the L3 vertebra when located caudally to the operation site than when located cranially (-27.7±19.8% vs. -12.8±27.1%; p<0.01)., Conclusions: The vertebral body BMD values are decreased at the adjacent of the posterolateral fusion with transpedicular screw fixation levels in both cephalad and caudad sides at an average of 9-months-follow-up postoperatively. This BMD loss persisted, but not worsened at an average of 32-months-follow-up. Vertebral BMD loss was significantly higher in the L3 vertebra when located caudally versus cranially to the surgery site., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Bone mineral density (BMD) and geometric bone measures are individually associated with prevalent osteoporotic fractures. Whether an aggregate of these measures would better associate with fractures has not been examined. We examined relationships between self-reported fractures and selected bone measures acquired by quantitative computerized tomography (QCT), a composite bone score, and QCT-acquired dual-energy X-ray absorptiometry-like total femur BMD in 2110 men and 2682 women in the Age, Gene/Environment Susceptibility-Reykjavik Study. The combined bone score was generated by summing gender-specific Z-scores for 4 QCT measures: vertebral trabecular BMD, femur neck cortical thickness, femur neck trabecular BMD, and femur neck minimal cross-sectional area. Except for the latter measure, lower scores for QCT measures, singly and combined, showed positive (p < 0.05) associations with fractures. Results remained the same in stratified models for participants not taking bone-promoting medication. In women on bone-promoting medication, greater femur neck cortical thickness and trabecular BMD were significantly associated with fracture status. However, the association between fracture and combined bone score was not stronger than the associations between fracture and individual measures or total femur BMD. Thus, the selected measures did not all similarly associate with fracture status and did not appear to have an additive effect on fracture status., (Copyright © 2014 The International Society for Clinical Densitometry. Published by Elsevier Inc. All rights reserved.)

Background:Bone mineral density (BMD) of the lumbar spine (L-spine) has been reported to be normal or increased in persons with chronic spinal cord injury (SCI).Objective:To determine BMD of the L-spine by dual-energy X-ray absorptiometry (DXA) and quantitative computerized tomography (qCT) in men with chronic SCI compared with able-bodied controls.Design:Cross-sectional, comparative study.Setting:Clinical research unit, Veterans Affairs Medical Center, Bronx, NY, USA and Kessler Institute of Rehabilitation, West Orange, NJ, USA.Methods:Measurements of the L-spine were made in 20 men with SCI and compared with 15 able-bodied controls. The DXA images were acquired on a GE Lunar DPX-IQ. The qCT images of the L-spine were acquired on a Picker Q series computerized tomographic scanner.Results:The mean ages for the SCI and control groups were 44±13 vs 42±9 years, and the duration of injury of the group with SCI was 14±11 years. There were no significant differences between the SCI and control groups for L-spine DXA BMD (1.391±0.210 vs 1.315±0.178 g/m2) or for L-spine DXA T-score (1.471±1.794 vs 0.782±1.481). L-spine qCT BMD was significantly lower in the SCI compared with the control group (1.296±0.416 vs 1.572±0.382 g/m2, P=0.05); the T-score approached significance (−1.838±1.366 vs −0.963±1.227, P=0.059). Subjects with moderate degenerative joint disease (DJD) had significantly higher T-scores by DXA than those without or with mild DJD.Conclusion:Individuals with SCI who have moderate to severe DJD may have bone loss of the L-spine that may be underestimated by DXA, reducing awareness of the risk of fracture.Spinal Cord (2009) 47, 628–633; doi:10.1038/sc.2008.169; published online 20 January 2009 [ABSTRACT FROM AUTHOR]