Trabecular Bone Score Preceding and during a 2-Year Follow-Up after Sleeve Gastrectomy: Pitfalls and New Insights

Bariatric surgery (BS) can have negative effects on bone health. Bone microarchitecture quality evaluation using the trabecular bone score (TBS) has not been described in patients after sleeve gastrectomy (SG). To test the hypothesis that the TBS is clinically useful for this population, we evaluated changes in bone mineral density (BMD) and the TBS in a longitudinal cohort study following SG. The measurements before surgery and after 12 and 24 postoperative months were as follows: weight, height, BMI, waist circumference (WC), BMD and TBS. The results at baseline showed the following: a mean BMI of 43 ± 0.56, TBS of 1.25 ± 0.02, lumbar spine BMD T-score of -0.4 ± 0.93, TBS T-score of -2.30 ± 0.21, significantly lower than BMD-T-score, and associated with a BMD-T-TBS-T gap (T-gap) of -2.05 ± 1.26 (-0.24 ± 0.13). One year after surgery, the TBS had significantly improved (+12.12% ± 1.5), leading to a T-gap of -0.296 ± 0.14, which remained stable at 2 years post-surgery. A correlation analysis revealed a significant negative correlation between the T-gap and WC (r = -0.43 p = 0.004). Our interpretation is that abdominal fat may interfere with image acquisition via increased tissue thickness, leading to a false low TBS at baseline. In conclusion, TBS should be interpreted with caution in patients with obesity and elevated WC. Additionally, we show that after SG, the LS microarchitecture measured using the TBS is partially degraded in up to 25% of patients. Further studies are warranted to assess hip bone microarchitecture changes after bariatric surgery.