Article
Correlation analysis of CT- and DXA-measured BMD in patients with lumbar spine instrumentation
Korrelationsanalyse von CT- und DXA-gemessener Knochendichte bei Patient*innen mit lumbalen Instrumentierungen
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Authors
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Anto Abramovic
- Medizinische Universität Innsbruck, Universitätsklinik für Neurochirurgie, Innsbruck, Österreich
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Sara Lener
- Medizinische Universität Innsbruck, Universitätsklinik für Neurochirurgie, Innsbruck, Österreich
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Christoph Orban
- Medizinische Universität Innsbruck, Universitätsklinik für Neurochirurgie, Innsbruck, Österreich
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Claudius Thomé
- Medizinische Universität Innsbruck, Universitätsklinik für Neurochirurgie, Innsbruck, Österreich
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Sebastian Hartmann
- Medizinische Universität Innsbruck, Universitätsklinik für Neurochirurgie, Innsbruck, Österreich
| Published: | June 4, 2021 |
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Outline
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Objective: Reduced bone mineral density (BMD) is a well-known risk factor for postoperative mechanical complications in spinal instrumentation of the elderly. In addition to dual x-ray absorptiometry (DXA) scans considered to be the gold standard for BMD screening, the use of computed tomography (CT) increases. The aim of this study was to investigate a correlation of BMD measured preoperatively using CT- and DXA-scans in patients planned for lumbar spinal fusion surgery.
Methods: All patients scheduled for lumbar spinal instrumentation who were screened by both preoperative lumbar CT- as well as DXA scans between 2009 and 2019 were retrospectively included. CT-BMD was measured using the “Schreiber-technique”, with a recommended time span between CT and DXA below 12 months. Patients with cervical or thoracic surgery as well as tumor-associated spine disease were excluded from the study.
Results: 64 patients (51 women, 13 men) with a mean age of 65 years were analyzed. The mean BMD was 95.2 ± 32.5 Hounsfield units (HU) on CT, while the BMD measured by DXA revealed to be 1.0 ± 0.3 and 0.6 ± 0.2 g/cm2 for the lumbar spine and the femoral neck, respectively. The Pearson correlation analysis demonstrated a significant correlation between CT-HU units and DXA scans of the femoral neck (R2 = 0.41, p<0.001), while no significant correlation between DXA scans of the lumbar spine and CT scans was shown (p>0.05). The correlation between DXA scans of the femoral neck and lumbar spine was also poor (p>0.05).
Conclusion: DXA scans particularly of the lumbar spine may not assess bone mineral density effectively. Due to various influential factors and local variations BMD measurement of the lumbar spine by the means of CT may be a more reliable tool. Further studies are necessary to evaluate the assessment of osteoporosis by preoperatively routinely available CT.
