Patient-Specific Finite Element Analyses Detect Significant Mechanical Therapeutic Effects on Osteoporotic Vertebrae During a Three-Year Treatment

Abstract

Analyses of the bone mass alone of osteoporotic vertebrae are not sufficient to predict fracture risks and assess the recovery of bone strength during drug treatment. Instead, finite element analyses (FEAs) is superior, because changes in the vertebral strength are strongly dependent on the inner vertebral stress distribution, which is related to the individual bone shape and bone density distribution in cancellous and cortical region. To investigate how FEAs can detect drug effects, we performed patient-specific FEAs of the first lumbar vertebra of osteoporotic patients at five time points (before therapy, and after 6 and 12 months and 2 and 3 years of therapy) during a 3-year drug treatment with alendronate and vitamin D, in four osteoporotic female patients in this study. The FEAs revealed notable decreases in the compressive principal strains in cancellous bone, but these decreases did not necessarily correspond to increases in the bone densities. In addition, statistical analyses by Friedman's test (nonparametric analysis) showed that evaluation based only on the average compressive principal strains over the 3-year treatment identified drug effects significantly, suggesting that compressive principal strain is an useful indicators for monitoring drug effects. Our data implied that compressive fracture of the vertebrae may be prevented as a result of the drug treatment, in a manner that was optimally detectable by patient-specific FEAs.

Finite element analysis of compression fractures at the thoracolumbar junction using models constructed from medical images

“…Imai et al ( 32 ) compared the results of FEM analysis and an actual compression experiment using samples of the thoracolumbar junction collected from fresh cadavers and demonstrated that bone strength and fracture sites can be predicted by FEM analysis. Tawara et al ( 33 – 35 ) reported the usefulness of FEM analysis for examining osteoporotic spines using CT images of bisphosphonate-treated patients, although they only analyzed limited intervertebral spaces and did not take into account the anatomical variability across the whole spine.…”

Design and Optimization Lattice Endoprosthesis for Long Bones: Manufacturing and Clinical Experiment

“…However, interest does not subside because of good usage potential in biomedicine [12][13][14][15]. Patient-based medicine became more widespread with the growth of technical abilities in computational mechanics and computed tomography scan quality [16][17][18]. Nowadays, it is possible to not only perform simulation of surgical treatment [19][20][21] but design the endoprosthesis [14,16] and predict biomechanical reaction [22][23][24].…”

“…Patient-based medicine became more widespread with the growth of technical abilities in computational mechanics and computed tomography scan quality [16][17][18]. Nowadays, it is possible to not only perform simulation of surgical treatment [19][20][21] but design the endoprosthesis [14,16] and predict biomechanical reaction [22][23][24]. Joint usage of the patient CT-data, patient-based design of the endoprosthesis, and additive manufacturing can increase the quality of the orthopedic treatment.…”

Biomechanical Study of the Effects of Balloon Kyphoplasty on the Adjacent Vertebrae

“…FEM has then been used to perform stress analyses to quantify strengths under external force from different directions and of different sizes [8]- [10]. Recent attempts that take individual patients' bone strengths into consideration have used CT data to understand the pathology of and assess therapeutic effects in osteoporosis [11] [12]. These techniques have also been used to evaluate surgeries using instrumentation [13].…”