gms | German Medical Science

Objectives: The purpose of this study is to analyze the prevalence of osteoporosis and osteopenia in patients undergoing lumbar fusion surgery (LFS) for degenerative conditions, to determine the proportion of undiagnosed osteoporosis, and to identify risk factors to guide preoperative bone mineral density (BMD) screening.

Methods: This retrospective cross-sectional study was conducted at an academic tertiary spine care center in the United States, including patients undergoing LFS for degenerative conditions from 2014 to 2023. Exclusion criteria were the absence of preoperative quantitative CT (qCT) data.qCT was performed at the L1/2 level prior to surgery, demographic and medical history were extracted from institutional databases. Descriptive and comparative statistics, univariable logistic regression analysis were performed to determine risk factors for previously diagnosed and undiagnosed osteoporosis. To optimize an age cut-off for detecting undiagnosed osteoporosis in patients without a prior diagnosis, and receiver operating characteristics (ROC) analysis was performed. Institutional review board approval was obtained prior to this study.

Results and conclusion: 675 patients were screened, and 578 (54% female) met the inclusion criteria. The median age of the patients was 65 years (interquartile range, IQR, 58–72), and their mean body mass index (BMI) was 29.5 (standard deviation, SD, 6.0). Out of the total number of patients, 182 (31%) had confirmed osteoporosis, with 114 having been previously diagnosed and 68 being newly identified through preoperative qCT. This indicates that 12% of the LFS patient cohort and 37% of patients with confirmed osteoporosis had undiagnosed osteoporosis. Additionally, 199 (34%) patients were diagnosed with osteopenia, resulting in a total of 66% of the cohort having impaired bone quality. The analysis of risk factors revealed that while being female significantly increased the risk for being previously diagnosed with osteoporosis (odds ratio [OR] 5.6; 95% confidence interval [CI] 3.4–9.7; p < 0.001), it did not have a significant effect on the risk of undiagnosed osteoporosis. On the other hand, patients with arterial hypertension had a higher risk of undiagnosed osteoporosis (OR 2.0; 95% CI 1.2–3.5; p = 0.011) but not for previously being diagnosed. ROC analysis revealed that individuals over the age of 65 were more likely to have undetected osteoporosis, with a sensitivity of 82% and specificity of 61% (area under the curve, AUC, 0.77).

In conclusion, there is a need for improved diagnostic vigilance and preoperative screening in patients undergoing LFS to mitigate the risk of postoperative complications associated with low BMD. Further research should focus on refining preoperative screening strategies to better identify patients at risk.