The Classic: Quantitative computed tomography of vertebral spongiosa: a sensitive method for detecting early bone loss after oophorectomy. 1982.
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History, 20th Century↗
Biomedical subjects
Christopher E Cann
Publications and source records attributed to Christopher E Cann.
Controlled trial of pamidronate in children with types III and IV osteogenesis imperfecta confirms vertebral gains but not short-term functional improvement.
UNLABELLED: Bisphosphonates have been widely administered to children with OI based on observational trials. A randomized controlled trial of q3m intravenous pamidronate in children with types III and IV OI yielded positive vertebral changes in DXA and geometry after 1 year of treatment, but no further significant improvement during extended treatment. The treated group did not experience significantly decreased pain or long bone fractures or have increased motor function or muscle strength. INTRODUCTION: Bisphosphonates, antiresorptive drugs for osteoporosis, are widely administered to children with osteogenesis imperfecta (OI). Uncontrolled pamidronate trials in OI reported increased BMD, vertebral coronal area, and mobility, and decreased pain. We conducted a randomized controlled trial of pamidronate in children with types III and IV OI. MATERIALS AND METHODS: This randomized trial included 18 children (4-13 years of age) with types III and IV OI. The first study year was controlled; 9 children received pamidronate (10 mg/m2/day IV for 3 days every 3 months). Four children in each group also received recombinant growth hormone (rGH) injections (0.06 mg/kg/day for 6 days/week). Seven children in the treatment group received pamidronate for an additional 6-21 months. All patients had L1-L4 DXA, spine QCT, spine radiographs, and musculoskeletal and functional testing. RESULTS: In the controlled phase, treated patients experienced a significant increase in L1-L4 DXA z score (p < 0.001) and increased L1-L4 mid-vertebral height (p = 0.014) and total vertebral area (p = 0.003) compared with controls. During extended treatment, DXA z scores and vertebral heights and areas did not increase significantly beyond the 12-month values. Fracture rate decreased significantly in the upper extremities (p = 0.04) but not the lower extremities (p = 0.09) during the first year of treatment. Gross motor function, muscle strength, and pain did not change significantly during the controlled or extended treatment phases. CONCLUSIONS: A controlled trial confirmed the spine benefits of short-term pamidronate treatment in children with types III and IV OI. Pamidronate increased L1-L4 vertebral DXA and decreased vertebral compressions and upper extremity fractures. Vertebral measures did not improve during the extended treatment phase. The treatment group did not experience decreased lower extremity long bone fractures, significant improvement in growth, ambulation, muscle strength, or pain. There was substantial variability in individual response to treatment.
Adolescent↗
Finite element models predict in vitro vertebral body compressive strength better than quantitative computed tomography.
The correlation between bone mineral density and vertebral strength is not based on mechanical principles and thus the method cannot reflect the effects of subtle geometric features and densitometric inhomogeneities that may substantially affect vertebral strength. Finite element models derived from quantitative computed tomography (QCT) scans overcome such limitations. The overall goal of this study was to establish that QCT-based "voxel" finite element models are better predictors of vertebral compressive strength than QCT measures of bone mineral density with or without measures of cross-sectional area. QCT scans were taken of 13 vertebral bodies excised from 13 cadavers (L1-L4; age: 37-87 years; M = 6, F = 7) and used to calculate bone mineral density (BMD(QCT)). The QCT voxel data were converted into linearly elastic finite element models of each vertebra, from which measures of vertebral stiffness and strength were computed. The vertebrae were biomechanically tested in compression to measure strength. Vertebral strength was positively correlated with the finite element measures of strength (r(2) = 0.86, P < 0.0001) and stiffness (r(2) = 0.82, P < 0.0001), the product of BMD(QCT) and vertebral minimum cross-sectional area (r(2) = 0.65, P = 0.0008), and BMD(QCT) alone (r(2) = 0.53, P = 0.005). These results demonstrate that highly automated "voxel" finite element models are superior to correlation-based QCT methods in predicting vertebral compressive strength and therefore offer great promise for improvement of clinical fracture risk assessment.
Adult↗