Bone Microstructure Changes due to Once-/Twice-Weekly Teriparatide Administration: A Report of Five Cases Using High-Resolution Peripheral Quantitative Computed Tomography

This study was conducted with the aim of presenting cases in which high-resolution peripheral quantitative computed tomography (HR-pQCT) was used to investigate changes in bone microstructure due to once-weekly/twice-weekly administration of teriparatide (TPTD). Of osteoporosis patients who participated in a non-inferiority trial (TWICE study: once-weekly vs twice-weekly TPTD) with lumbar bone mineral density (BMD) as the primary endpoint, five cases scanned by HR-pQCT before TPTD administration were analyzed. Two cases were given once-weekly TPTD, three were given twice-weekly TPD, and HR-pQCT was repeated after 48 weeks. A sufficient anabolic effect of once-weekly/twice-weekly TPTD on the trabecular and cortical bone at the tibia was obtained. In addition, the average change in cortical porosity (Ct.Po) was only 0.3% in the tibia and 0.2% in the radius. These findings indicate that once-weekly and twice-weekly TPTD can be expected to improve bone microstructure, and the increase in Ct.Po may be suppressed.

Trabecular Bone Score (TBS) in Patients with Early Ankylosing Spondylitis—Limited Utility

Purpose: Ankylosing spondylitis (AS) not only results in pathological ossification of the spine, but can also be associated with osteoporosis. Due to the presence of syndesmophytes and possible involvement of the hip joints, classical dual X-ray absorptiometry (DXA) is of limited use in patients with advanced stages of AS. Trabecular bone score (TBS) is a method complementary to DXA, providing additional information about bone microarchitecture. There is a growing body of evidence for the usefulness of TBS in AS patients. The aim of this study was to assess the clinical utility of TBS in patients with AS. Methods: Patients with AS underwent DXA with additional TBS assessment. A cross-sectional analysis of the frequency of osteoporosis and bone microarchitecture deterioration and their association with patients’ characteristics was done. Results: A total of 51 male patients, mean age 40.7 years, were enrolled. Osteoporosis was diagnosed in seven patients (13.7%). Lumbar bone mineral density (BMD) was higher (p < 0.001) than femoral BMD, indicating abnormal BMD readings in the spine caused by syndesmophytes. Patients with DXA-diagnosed osteoporosis had lower TBS (p = 0.03) and TBS T-score (p = 0.043) values compared to patients without osteoporosis. However, disturbed bone microarchitecture (TBS < 1.23) was present in only three patients (5.9%). None of the patients had a history of an osteoporotic fracture. A lower TBS T-score (p = 0.032) was demonstrated in patients with sacroiliitis grade 4 than in patients with sacroiliitis grade 2, with no significant differences in BMD and T-score values. Conclusion: Among patients with early AS, the clinical utility of TBS is limited—it does not add value to DXA.

Hounsfield unit value on CT as a predictor of cage subsidence following stand-alone oblique lumbar interbody fusion for the treatment of degenerative lumbar diseases

Background To investigate the correlation between vertebral Hounsfield unit (HU) values and cage subsidence in patients treated with stand-alone (SA) OLIF. Methods A retrospective review of collected data was performed on 76 patients who underwent SA OLIF. We utilized the HU value for lumbar bone mineral density (BMD) obtained on preoperative CT. The vertebral HU values of patients with subsidence were compared to those without subsidence. The correlation between cage subsidence and clinical score was investigated. Results Sixteen patients (21.1%) had at least radiographic evidence of interbody cage subsidence. The average cage subsidence was 2.5 ± 1.3 mm (range 0.9-4.8 mm). There were no significant differences in sex, BMI, preoperative diagnoses, or fused level (p > 0.05); however, there were significant differences between the cage subsidence group and the nonsubsidence group in age, average of the lowest T-score, and average HU value, including for the L1 vertebrae, L1-L4 horizontal plane, and L1-L4 sagittal plane (p < 0.05). The average HU value of the L1-L4 horizontal plane showed a more predictable AUC of 0.909 (95% CI, 0.834–0.984; P < 0.001) compared with the average of the lowest T-score following an AUC of 0.791 (95% CI, 0.674–0.909; P < 0.001). Based on logistic regression analysis, the average HU value of the L1-L4 horizontal plane (OR, 0.912; 95% CI, 0.861–0.966; P = 0.002) was an independent factor influencing cage subsidence. Conclusions Patients with lower average HU values of the lumbar vertebrae are at a much higher risk of developing cage subsidence after SA OLIF. Measurement of preoperative HU values on preexisting CT scans could be rapid, simple and feasible.

Effects of Abdominal Aortic Calcification and Facet Joint Arthritis On Lumbar Bone Mineral Density Using Dual-Energy X-Ray Absorptiometry

Background Abdominal aortic calcification (AAC) may overestimate lumbar bone mineral density (BMD) examined by dual-energy X-ray absorptiometry (DXA); however, the degree of effect of AAC on lumbar BMD has not been quantified. In particular, no study has quantitatively compared and analysed segmental BMD and AAC using computed tomography (CT) scan. Thus, this study aimed to quantify the effect of AAC on BMD measurements using DXA via multiple linear regression analysis. Methods This study retrospectively reviewed participants >30 years of age who underwent DXA and spinal CT scans between 2014 and 2016. Variables that significantly affected the BMD of each lumbar segment were identified. Additionally, segmental facet joint arthritis (FJA) and AAC volume were evaluated using CT. Results A total of 620 subjects (153 males and 467 females) were included. The mean age was 71.6 ± 9.1 years (range, 31–89 years). AAC had the highest prevalence in L3 (45.2%), followed by L4 (41.1%). The average volume of AAC was the highest in L4 at 213.67 ± 443.82 mm3, followed by L3 at 161.95 ± 338.09 mm3. Our regression model found that Ln (L4BMD) was significantly correlated with age, BMI, FJA, and AAC volume in female subjects. Additionally, L4 BMD might be overestimated by approximately 0.90% for every 100 mm3 increase in AAC volume. The results for Ln (L3BMD) were almost identical. However, these relationships were not observed in males. Conclusion According to this model, AAC may overestimate lumbar BMD examined by DXA in a dose-dependent manner in females.

Association Between Bone Mineral Density And Serum Creatinine In People < 46 Years Old

Purpose: To research the relationship between serum creatinine and lumbar bone mineral density in people aged <46 years. Methods: A total of 10,968 subjects from the American Nhanes database were included in this cross-sectional study, including 5,744 males (mean age 26.2 years) and 5224 females (mean age 26.7 years). The exposure factor is the serum creatinine value, and the outcome indicator is the lumbar bone mineral density. This study mainly used multivariate linear regression analysis to test the relationship between lumbar bone mineral density and serum creatinine. Results: In the multivariate linear regression analysis, serum creatinine was positively correlated with lumbar bone mineral density (β = 0.122, 95%CI: 0.047-0.198), but in the subgroup analysis stratified by sex, this positive correlation only exists in the female population (Β = 0.186, 95%CI: 0.070-0.301).Conclusions: Our study found that in women aged <46 years with normal renal function, there is a positive correlation between serum creatinine and lumbar BMD. And in those people, the determination of serum creatinine can provide a sensitive biomarker for the early identification and treatment of Osteopenia or osteoporosis.

Hypertryptasemia and Mast Cell-Related Disorders in Severe Osteoporotic Patients

Purpose. Systemic mastocytosis (SM) is characterized by a clonal proliferation of neoplastic mast cells (MCs) in one or more extracutaneous organs including the bone marrow (BM). SM is often associated with osteoporosis (OP) and fractures. Hypertryptasemia usually occurs in SM. We investigated the prevalence of hypertryptasemia in a series of severe osteoporotic patients, the performance of the tryptase test in diagnosing SM in these patients, and their bone features. Methods. The medical records of 232 patients (168 females and 64 males) with a diagnosis of OP (50.4% with fractures) and a serum tryptase assessment were reviewed. BM assessment was performed in a subset of hypertryptasemic patients; clinical, biochemical, and radiographic data were collected. Results. Hypertryptasemia was detected in 33 patients. BM assessment ( n = 16 ) was normal in 8 hypertryptasemic patients, while BM criteria for the diagnosis of SM were met in 3 patients, MC alterations were detected in 4 patients, and one patient presented a polycythemia vera. Serum tryptase levels were higher than 11.4 ng/ml in all patients with BM alterations. The best cut-off of tryptase level related to BM alterations was 17.9 ng/ml, with a sensibility and sensitivity of 75% ( AUC = 0.797 and P = 0.015 by ROC analysis). All osteoporotic patients with hypertryptasemia experienced at least one vertebral fracture associated with a severe reduction of the lumbar bone mineral density. Conclusions. The prevalence of MC-related disorders in severe OP was 3.0%, accounting for the 7.4% of the secondary causes of OP. MC-related disorders may be involved in bone fragility and assessment of serum tryptase is useful to detect MC-related disorders.