Abstract:

Aim: Bone mineral density (BMD) is vital in spinal fusion surgery. Dual X-ray absorptiometry (DEXA) is the gold standard for evaluating BMD. In this study, we aim to assess the bone density of the patients using Hounsfield units (HU) who underwent spinal surgery with instrumentation. Material and Method: Computed tomography (CT) and DEXA results of 99 cases of 40 years of age or older who had posterolateral fusion operation between 2014 and 2017 were evaluated retrospectively. The HU values of the vertebral body obtained from the lumbar CT, which is routinely used in surgical planning, were measured with the image archiving and communication system (PACS; Maroview, Infinitt Healthcare). Three measurements were taken from each vertebra. Hounsfield unit values were determined according to age groups. These results were compared with the L1–4 DEXA results acquired before the operation and/ or within six months. Results: HU values of patients obtained from CT were classified between four age groups. Hounsfield unit values of each vertebral level were compared with the T score obtained with DEXA. The correlations of the HU value with the T score were significant (p <0.001). The mean HU values of the compared levels decreased consistently over the ten years. The differences were statistically significant. There was no significant difference between HU values in age groups. Conclusion: Estimating the osteopenic/ osteoporotic spine by measuring the HU values from CT is a simple, cost-effective method that helps surgical planning at instrumentation.

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