Microstructural trabecular bone from patients with osteoporotic hip fracture or osteoarthritis: Its relationship with bone mineral density and bone remodelling markers

Osteoporosis (OP) and osteoarthritis (OA) are the most prevalent musculoskeletal disorders in the elderly but the relationship between them is unclear. The purposes of this study are to analyze the bone turnover markers (BTM), bone mineral density (BMD) and the structural and mechanical properties of trabecular bone in patients with OP and OA, and to explore the relationship between these two diseases. We studied 12 OP patients and 13 OA patients. We analyzed BTM (β-CrossLaps and PINP), BMD and microstructural and biomechanical parameters (micro-CT). Our results were: OP group has higher levels of β-CrossLaps and lower BMD at the femoral neck. Also, OP patients have a decreased volume of trabecular bone and less trabecular number, with architecture showing prevalence of rod-like trabeculae and worse connectivity than OA patients. The biomechanical parameters were worse in OP patients. BMD was correlated with almost all the structural and biomechanical parameters. Moreover, β-CrossLaps was negatively correlated with hip BMD and with bone surface density and positively with trabecular separation. BTM, BMD and bone microstructural changes in osteoporosis are opposite to those of OA. These findings justify a less resistant bone with higher risk of fragility fractures in OP patients. These histomorphometric and biomechanical changes may be suspected by measuring of BMD and β-CrossLaps levels.     

EMAS position statement: The management of postmenopausal women with vertebral osteoporotic fracture

Introduction

Osteoporotic vertebral fractures are associated with significant morbidity, excess mortality as well as health and social service expenditure. Additionally, women with a prevalent osteoporotic vertebral fracture have a high risk of experiencing a further one within one year. It is therefore important for the physician to use a diagnostic and therapeutic algorithm for early detection and effective treatment of vertebral fractures.

Aims

The aim of this position statement is to provide and critically appraise evidence on the management of women with a vertebral osteoporotic fracture.

Materials and methods

Literature review and consensus of expert opinion.

Results and conclusions

The management of women with osteoporotic vertebral fractures includes measures to reduce pain providing early mobility, to support the affected spine ensuring fracture healing, as well as starting treatment for osteoporosis itself. Any other underlying pathology should be sought and treated. Early detection and treatment is essential as there is an increased risk of further fractures in patients with vertebral fractures. Treatment will depend on the underlying causes of bone loss, efficacy in any particular situation, cost and patient preference.     

Evaluation of methods for prediction of bone mineral density by clinical and biochemical variables in perimenopausal women

Objectives: to predict spinal and femoral bone mineral density (BMD) in perimenopausal women from simple clinical and biochemical variables. Methods: 2016 women 3–24 months past last menstrual bleeding. Mean age 50.1±2.8 years. Age, height, weight, number of full term pregnancies, weekly hours of physical activity, sunbathing habits, use of sun bed, daily intake of calcium and vitamin D, smoking habits, consumption of alcohol, coffee, and tea, history of forearm or femoral neck fractures among the parents, serum osteocalcin (S-OC), serum bone specific isoenzyme of alkaline phosphatase (BSAP), and urine hydroxyproline/creatinine ratio (U-OHP) were used as predictors in three different mathematical models. Lumbar spine (L2–L4) and femoral neck BMD were measured by DEXA. Three mathematical models (multiple regression, logistic regression, and discriminant analysis) were applied. Results: the multiple regression explained 19–21% of the total variation, and the logistic regression and discriminant function had a sensitivity between 53 and 67% with specificity ranging from 67 to 80%. Age, S-OC, serum bone specific alkaline phosphatase, and a maternal history of forearm or femoral neck fractures seemed to be reproducible risk factors for low bone mineral density irrespective of the mathematical model applied. When applied to a separate population, the models performed poorly. Conclusions: Simple clinical and biochemical variables are not useful to predict spinal and femoral BMD in the individual perimenopausal woman.     

经皮椎体后凸成形术治疗骨质疏松性椎体压缩骨折

目的初步探讨应用球囊扩张椎体后凸成形术治疗骨质疏松性椎体压缩骨折的临床疗效。方法应用球囊扩张椎体后凸成形术治疗骨质疏松性椎体压缩骨折患者24例28个椎体，并随访4～11个月，平均8个月。结果所有患者手术均获成功，无脊髓神经损伤，病椎疼痛缓解，后凸畸形平均矫正20°，随访期间，疗效满意，无病椎高度丢失。结论应用经皮椎体成形术治疗骨质疏松性椎体压缩骨折能明显改善患者疼痛症状，恢复椎体高度，矫正后凸畸形，是一种安全的微创方法。     

Relationship between BMD, dental panoramic radiographic findings and biochemical markers of bone turnover in diagnosis of osteoporosis

OBJECTIVE: Mandibular indices, measured on panoramic radiographs, may be useful screening implements for low skeletal bone mass density (BMD). Recent studies suggest that radiographic examination of mandible may constitute an effective process for the early diagnosis of osteoporosis. Biochemical markers of bone turnover may be of value for prediction of individual bone loss and they may help in predicting risk of fracture in elderly women. In contrast to the vast information available on dental radiographic findings and BMD only scarce data exist on the relationship between panoramic mandibular indices and biochemical markers. The aim of this study was to examine the diagnostic performance of dental panoramic radiography and biochemical markers of bone turnover in relation to BMD at the spine in a group of postmenopausal women. SUBJECTS AND METHODS: An assessment of the number of lost teeth, mandibular cortical width (MCW) at the mental region and morphologic classification of mandibular inferior cortex (MIC grade) was performed on dental panoramic radiographs in a group of 141 postmenopausal women 38-81 years of age. BMD at the lumbar spine was measured by dual energy X-ray absorptiometry. BMD values were categorized as normal (T-score greater than 1.0), and as indicative of osteopenia (T-score -1.0 to -2.5) or osteoporosis (T-score less than -2.5) according to the World Health Organization classification. Serum bone alkaline phosphatase (BAP) was measured with an enzyme immunoassay. Cross-linked N-telopeptides of type I collagen (NTx) corrected for creatinine secretion, was measured with a competitive-inhibition enzyme-linked immunosorbent assay ELISA. RESULTS: In our study, a decrease in MCW by 1mm increases the likelihood of osteopenia or osteoporosis to 47% (p-value<0.05), having taken into consideration the effect of the years elapsed since menopause. The increase of alkaline phosphatase (ALP) per unit increase the likelihood of osteopenia or osteoporosis to 14% (p-value<0.05), having checked the effect of the years since menopause. A decrease in MCW by 1mm increases the likelihood of moderately or severely eroded cortex to 97% (p-value<0.001). The increase in ALP per 1 unit increases the likelihood of moderate or severe erosion per 10% (p-value<0.05), taking into account the years since menopause. CONCLUSIONS: Our results suggest that dentists have sufficient clinical and radiographic information that enables them to play a significant role in early diagnosis of osteoporosis in postmenopausal women. Panoramic radiographs and biochemical markers of bone turnover may be of value for prediction of individual bone loss and they may help in predicting risk of fracture in elderly women.     

糖尿病相关骨转换指标研究进展

骨质疏松症是糖尿病常见并发症之一,也是影响糖尿病患者生存质量及寿命的主要原因.骨密度(bone mineral density,BMD)测定是早期诊断骨质疏松的标准,然而,一些BMD正常的潜在骨质疏松患者易被忽略.因此,寻找敏感性和特异性更高的骨代谢标志物来预测早期骨代谢异常具有重要意义.     

PKP治疗骨质疏松性椎体压缩骨折疗效分析

目的总结经皮椎体后凸成形术(Percutaneous kyphoplasty,PKP)治疗骨质疏松性椎体压缩骨折的临床疗效。方法收集2009年08月~2013年08月泰州市中医院骨科采用PKP治疗的72例(80个椎体)患者资料;采用疼痛视觉模拟评分(Visual analogue scale,VAS)进行手术前后疼痛评估,观察Cobb角变化及并发症情况。结果术后随访1年以上;所有病例疼痛症状均缓解,VAS评分术前(8.0±0.82)分、术后(3.7±0.66)分,差异有统计学意义(0.05);Cobb角术前为(23.49±12.75)°,术后(10.35±5.57)°,差异均有统计学意义(0.05);本组病例手术均获得成功,12例患者出现骨水泥渗漏,8例渗漏到椎体旁,未出现椎体后缘渗漏,均未出现神经症状;相邻椎体骨折2例,伤椎再骨折3例。结论 PKP治疗骨质疏松性椎体压缩骨折可快速有效地缓解患者疼痛、恢复病椎高度,术中术后并发症发生率低。     

Ultra low-dose hormone replacement therapy and bone protection in postmenopausal women

OBJECTIVES: The aim of the present study was to evaluate the effects of low doses of hormone replacement therapy (HRT) in normal young postmenopausal women. METHODS: In an open trial healthy, non-obese postmenopausal women received for 2 years a low-dose continuous combined HRT (LD-HRT) containing 1mg estradiol+0.5 mg norethisterone acetate each pill for 28 days, or 0.5 mg of 17beta-estradiol and 0.25 mg of norethisterone acetate (Ultra low dose, Ultra-LD-HRT) along with 1000 mg of calcium per day. Control group consisted of women receiving only 1000 mg of calcium per day, for 2 years. Menopausal symptoms were evaluated by the Green climacteric scale for the first 12 weeks of the study while bleeding profiles, bone mineral density (BMD) and bone turnover were assessed for 24 months. RESULTS: LD-HRT and Ultra-LD-HRT were effective in reducing menopausal clinical symptoms. In the control group, BMD significantly (P<0.05) decreased at the spine (-2.8+/-0.2%), and femoral neck (-2.8+/-0.7%). In LD-HRT treated group BMD showed a significant (P<0.05) increase at the spine (5.2+/-0.7%), and femoral neck (2.8+/-0.4%) after 24 months. In the Ultra-LD-HRT treated women spine and femoral neck BMD showed a significant (P<0.05) increase (2.0+/-0.3 and 1.8+/-0.3%, respectively) after 24 months. In these women treated with LD-HRT and Ultra-LD-HRT the BMD values were significantly (P<0.05) different from those measured in calcium-treated women. CONCLUSIONS: LD-HRT and Ultra-LD-HRT can alleviate subjective symptoms providing an effective protection against the postmenopausal decrease of BMD.     

骨转换生化标志物

骨基质和骨细胞的代谢(合成与分解)产物,构成了骨转换(骨吸收和骨形成)生化标志物。这些标志物在体液(血液和尿液)中水平的改变,代表了全身骨组织的动态变化。检测骨转换生化标志物在血尿中的水平,对于科学评价代谢性骨病(骨质疏松及其他代谢性骨病)的临床诊断、疗效反应、骨折危险性的预测以及个体骨转换状态等能提供重要信息。本文仅对骨转换标志物的一般生化、测定及应用予以梗概介绍。     

Identification of the risk factors for osteoporosis among postmenopausal women

ObjectivesThe aim of this study was to determine the effect of different durations of menopause at the time of bone mineral density (BMD) measurement and of different age at menopause intervals on the prevalence of osteopenia and osteoporosis among untreated postmenopausal women. We also assessed related factors leading to low BMD.MethodsA total of 2769 postmenopausal women who had not taken any anti-osteoporosis treatment and/or hormone replacement therapy were divided into three groups according to duration of menopause at the time of BMD measurement. The women were also evaluated in four different age groups according to their age at menopause onset. Multinomial logistic regression analysis was used to determine related factors leading to low BMD. Investigated parameters include demographic characteristics, plasma glucose, lipids, and lipoproteins.ResultsAccording to World Health Organization (WHO) criteria, among 2769 patients, 449 (16.2%) were identified as having osteoporosis, 1085 (39.2%) as having osteopenia, and 1235 (44.6%) as having normal BMD. Osteoporosis was determined in 10.6% and 16.2% of women with menopause duration of 0–3 years and 4–7 years, respectively, whereas this rate was 31.9% in women with menopause duration of over 7 years (p = 0.001). The percentages for osteopenia remained constant among the three different menopause durations (0–3 years: 37.2%, 4-7 years: 42.1%, and >7 years: 40.9%). Thirty percent of women with age at onset of <40 years were osteoporotic. However, the percentages of women with osteoporosis among the other age groups were similar (40–46 years: 18.3%, 47–52 years: 14.1%, and >52 years: 15.4%). The percentages for osteopenia remained relatively constant among the four age groups (36.7, 40, 39.1 and 39%). According to the multinomial logistic regression analysis, duration of menopause at the time of BMD test and parity were positively correlated with both osteoporosis and osteopenia, while glucose level was negatively correlated with both osteoporosis and osteopenia. Age at menopause was negatively correlated only for osteoporosis. Low-density lipoprotein cholesterol (LDL-c) level may be accepted as a clinically significant factor for osteopenia (OR: 1.01; CI_95%: 1.00–1.02). No differences were determined in the prevalence of osteopenia and osteoporosis in women with menopause duration of >7 years when evaluated according to the four menopause age groups as described before (p = 0.74). Contribution to the regression model was 0.8% by age at menopause, 5.6% by menopause duration at time of BMD measurement, 5.8% by both factors.ConclusionAccording to our results, osteoporosis is related more to the duration of menopause at the time of BMD measurement rather than the age at menopause among untreated postmenopausal women. High parity was determined as another risk factor for low BMD.     

Serum Cathepsin K levels are not suitable to differentiate women with chronic bone disorders such as osteopenia and osteoporosis from healthy pre- and postmenopausal women

Objectives

Cathepsin K (CatK) is expressed in high levels in osteoplasts and therefore plays an important role in bone resorption. Thus CatK serum levels may be useful in the diagnosis of chronic bone disorders such as osteopenia and osteoporosis. Therefore we aimed at studying CatK levels in women putatively free of known skeletal disorders.

Study design

In total, 121 voluntary women, 27 premenopausal women aged between 20 and 45 years, and 94 postmenopausal women aged 59–81 years, all free of known skeletal disorders were included. All women underwent bone density measurement, routine labor parameter and measurement of serum CatK levels.

Main outcome measures

Based on WHO criteria, women were stratified in four groups (premenopausal: healthy; postmenopausal: healthy, osteopenia, osteoporosis), and their CatK levels were statistically analyzed.

Results

Using WHO criteria 21 postmenopausal women had normal bone mineral density (BMD), 49 had osteopenia and 24 had osteoporosis. All 27 premenopausal women had normal BMD. There were no significant differences in CatK between these groups. ROC analysis resulted in poor diagnostic validity of CatK, where the area under curve was 0.544. There was no correlation neither between CatK and other biomarkers as C-telopeptide crosslaps (CTX) or bone-specific alkaline phosphatase (BAP) nor between CatK and age.

Conclusions

Serum levels of CatK are not suitable to differentiate women with osteoporosis from healthy subjects.     

PKP技术治疗骨质疏松性椎体骨折不愈合的临床观察

目的探讨和评估经皮椎体后凸成形术﹙PKP﹚治疗骨质疏松性椎体压缩骨折不愈合的方法与临床疗效。方法自2006年3月~2011年3月,在局麻下行PKP技术治疗老年椎体压缩骨折不愈合患者28例34个椎体,术后进行AVS、ODI临床疗效和影像学评估。结果所有患者获得3~48个月﹙平均24.6个月﹚随访。23例术后腰背部疼痛消失,5例疼痛明显减轻,VAS由8.3±2.3减少到2.5±1.8,ODI评分由﹙76.5±13﹚%减少至﹙23.5±8﹚%,与手术前有显著性改善﹙0.001﹚。术后X线片及CT提示伤椎内骨水泥填充部位满意,无硬脊膜受压表现。测量X光片术前单椎体后突成角为平均23±8°,术后平均13±5°,改善角度平均10±3°。椎体高度术前平均1.3±0.6cm,术后平均2.1±0.7cm,高度增加平均0.8±0.3cm。手术前后后突角度及椎体高度的恢复均有显著性差异﹙0.001﹚。结论 PKP技术治疗骨质疏松性椎体压缩骨折不愈合是一种脊柱微创技术,适应于手术耐受性差的老年人,是治疗老年椎体压缩骨折不愈合的有效方法。     

Relation between obesity and bone mineral density and vertebral fractures in Korean postmenopausal women

Purpose

The traditional belief that obesity is protective against osteoporosis has been questioned. Recent epidemiologic studies show that body fat itself may be a risk factor for osteoporosis and bone fractures. Accumulating evidence suggests that metabolic syndrome and the individual components of metabolic syndrome such as hypertension, increased triglycerides, and reduced high-density lipoprotein cholesterol are also risk factors for low bone mineral density. Using a cross sectional study design, we evaluated the associations between obesity or metabolic syndrome and bone mineral density (BMD) or vertebral fracture.

Materials and Methods

A total of 907 postmenopausal healthy female subjects, aged 60-79 years, were recruited from woman hospitals in Seoul, South Korea. BMD, vetebral fracture, bone markers, and body composition including body weight, body mass index (BMI), percentage body fat, and waist circumference were measured.

Results

After adjusting for age, smoking status, alcohol consumption, total calcium intake, and total energy intake, waist circumference was negatively related to BMD of all sites (lumbar BMD p = 0.037, all sites of femur BMD p < 0.001) whereas body weight was still positively related to BMD of all sites (p < 0.001). Percentage body fat and waist circumference were much higher in the fracture group than the non-fracture group (p = 0.0383, 0.082 respectively). Serum glucose levels were postively correlated to lumbar BMD (p = 0.016), femoral neck BMD (p = 0.0335), and femoral trochanter BMD (p = 0.0082). Serum high density lipoprotein cholesterol (HDLC) was positively related to femoral trochanter BMD (p = 0.0366) and was lower in the control group than the fracture group (p = 0.011).

Conclusion

In contrast to the effect favorable body weight on bone mineral density, high percentage body fat and waist circumference are related to low BMD and a vertebral fracture. Some components of metabolic syndrome were related to BMD and a vertebral fracture.     

Effects of nandrolone decanoate on bone mass in established osteoporosis

A double-blind, randomized, placebo-controlled study was conducted in 46 postmenopausal women with established osteoporosis in order to assess the long-term effects of nandrolone decanoate on the bone mineral density (BMD) of the lumbar vertebrae and of the distal third of the radius and on the biochemical markers of bone turnover. The patients received intramuscular injections of placebo or 50 mg nandrolone decanoate every 3 weeks for 18 months. Thirty-two of the initial 46 patients completed 1 year of study and 25 completed the whole study period of 18 months. Overall, vertebral BMD increased by 2.9% in the nandrolone decanoate group and fell by 2.3% in the placebo group. Radial BMD showed a slight but transient improvement, with a subsequent return to basal levels in the nandrolone decanoate group, whereas there was a progressive decrease in the placebo group. Patients treated with nandrolone decanoate also complained less of bone pain. Urinary hydroxyproline decreased significantly in treated patients, whereas osteocalcin tended to increase, but the change was not significant. HDL cholesterol concentrations decreased only slightly and haemoglobin increased significantly in the nandrolone decanoate group. Two patients treated with nandrolone decanoate withdrew from the study because of hirsutism and hoarseness. The results indicate that nandrolone decanoate exerts positive effects on vertebral BMD and on bone pain in patients with established postmenopausal osteoporosis.     

Vertebral fracture assessment in Moroccan women: Prevalence and risk factors

Introduction

Vertebral fracture assessment (VFA) is a fast, low-radiation technique which produces images that are of sufficient quality to be used to diagnose the presence of vertebral deformity consistent with fracture.

Objective

To study prevalence and risk factors of vertebral fractures using VFA in asymptomatic Moroccan women.

Methods

The study cohort consists of a population of 328 consecutive women aged over 50 (mean age, weight and BMI of 65 ± 6.5 (50–84) years, 72.0 ± 12.8 (42–125) and 29.4 ± 5.0 (17.1–45.8) kg/m², respectively). Lateral VFA images and scans of the lumbar spine and proximal femur were obtained by two technologists using a GE Healthcare Lunar Prodigy densitometer. Vertebral fractures were defined using a combination of Genant semiquantitative (SQ) approach and morphometry.

Results

68% of vertebrae from T4–L4 and 75% from T8–L4 were adequately visualized on VFA. Vertebral fractures (grades 2 or 3) were detected in 25.6% (84/328) of these women. Thirty-two of women with VFA-identified fracture (38.0%) had only a single vertebral fracture, while the other 61.9% had two or more. Fractures were most common in the mid-thoracic spine and at the thoraco-lumbar junction. As would be expected, the prevalence of VFA-detected fractures increased with age and as BMD declined. Stepwise regression analysis showed that presence of vertebral fracture was mainly related to the spine osteoporotic status, age older than 65, history of peripheral fracture and more than six parities.

Conclusion

Vertebral fractures are common in asymptomatic Moroccan women and are related to age, low BMD, history of fracture and multiparity.     

Panoramic radiomorphometry and vertebral fractures in Spanish postmenopausal women

Objective

To evaluate the relationship between panoramic radiomorphometric indexes, and the presence of osteoporotic fractures in a Spanish postmenopausal women.

Methods

A sample of 120 women (60 with fragility spine fractures and 60 healthy), aged 55–70 years, with fragility spine fractures, were included in this cross-sectional study that was conducted from 2008 to 2011. All the women were referred to undergo a radiological spine examination, spinal densitometry and a panoramic radiograph for assessing osteoporosis using 3 radiomorphometric indexes: Panoramic Mandibular Index (PMI), Mental Index (MI) and Mandibular Cortical Index (MCI). According to mandibular cortical shape, in MCI, three groups were defined: C3 (osteoporosis), C2 (osteopenia), C1 (health).

Results

Significant differences were found between all the MCI groups due to their composition between fractures and non-fractures. C1 group (healthy) has less fractures women than C2 (Bonferroni p < 0.001), C1 has less fractures than C3 (Bonferroni p < 0.001) and finally, C2 has less fractures than C3 (Bonferroni p < 0.006). PMI and MI values were significantly lower in cases than in controls (U Mann–Whitney p < 0.001).

Conclusions

Panoramic radiomorphometrics mandibular indexes such as MCI, PMI, and MI, may be useful for identifying the population at higher risk for fracture. The relationship between panoramic index and osteoporosis remains unclear and further studies using fragility fracture as a real marker of osteoporosis are warranted to clarify the exact role and effect of one condition on the other and the corresponding clinical implications.     

不同治疗方法对绝经后乳腺癌患者骨密度的影响

目的 探讨不同治疗方法 对绝经后乳腺癌患者骨密度(BMD)的影响.方法 研究分为健康对照组(50例)、肿瘤组[48例,其中24例再行他莫昔芬(TAM)组治疗].采用双能X线骨密度仪(DEXA)测定所有研究对象的基线BMD.肿瘤组术后均进行辅助化疗,其中24例(TAM组)化疗后继续使用TAM行内分泌治疗.用DEXA测量腰椎和左髋部位的BMD,比较肿瘤组化疗前、后以及TAM组行内分泌治疗8个月后BMD变化.结果 肿瘤组化疗后腰椎部位BMD(0.87±0.15)g/cm2比化疗前(0.93±0.15)g/cm2明显降低(P<0.05);TAM组行内分泌治疗8个月后腰椎BMD(0.90±0.04)g/cm2和股骨颈(0.74±0.05)g/cm2等左髋部位的BMD均有明显增加(P<0.05).结论 化疗可能导致绝经后乳腺癌患者BMD的下降,而TAM治疗能缓解化疗引起的BMD降低.     

Panoramic radiomorphometry and vertebral fractures in Spanish postmenopausal women

ObjectiveTo evaluate the relationship between panoramic radiomorphometric indexes, and the presence of osteoporotic fractures in a Spanish postmenopausal women.MethodsA sample of 120 women (60 with fragility spine fractures and 60 healthy), aged 55–70 years, with fragility spine fractures, were included in this cross-sectional study that was conducted from 2008 to 2011. All the women were referred to undergo a radiological spine examination, spinal densitometry and a panoramic radiograph for assessing osteoporosis using 3 radiomorphometric indexes: Panoramic Mandibular Index (PMI), Mental Index (MI) and Mandibular Cortical Index (MCI). According to mandibular cortical shape, in MCI, three groups were defined: C3 (osteoporosis), C2 (osteopenia), C1 (health).ResultsSignificant differences were found between all the MCI groups due to their composition between fractures and non-fractures. C1 group (healthy) has less fractures women than C2 (Bonferroni p < 0.001), C1 has less fractures than C3 (Bonferroni p < 0.001) and finally, C2 has less fractures than C3 (Bonferroni p < 0.006). PMI and MI values were significantly lower in cases than in controls (U Mann–Whitney p < 0.001).ConclusionsPanoramic radiomorphometrics mandibular indexes such as MCI, PMI, and MI, may be useful for identifying the population at higher risk for fracture. The relationship between panoramic index and osteoporosis remains unclear and further studies using fragility fracture as a real marker of osteoporosis are warranted to clarify the exact role and effect of one condition on the other and the corresponding clinical implications.     

椎体骨微结构参数与椎弓根螺钉固定强度的相关性

目的 测量不同骨密度（bone mineral density, BMD）条件下椎体松质骨显微结构参数,并与椎弓根螺钉拔出力作相关性分析,以了解与螺钉稳定性相关的骨显微结构参数,进一步明确螺钉松动的原因。方法 采用新鲜尸体脊柱标本,根据BMD检测结果,按临床诊断标准分为骨质正常、骨量减少、骨质疏松和重度骨质疏松4个水平。然后植入椎弓根螺钉,进行螺钉轴向拔出实验,测定最大拔出力（maximum pullout strength, MPS）。收集螺钉拔出实验后椎体标本,在椎体中央部钻取松质骨柱状样本,对样本进行显微CT扫描,获取椎体松质骨显微结构参数,并进行各项指标的不同BMD水平间的比较分析,在了解这些指标随骨质疏松程度加重的变化规律的基础上,再对骨显微结构参数与所对应的螺钉MPS开展相关性分析。结果BMD水平从正常下降到重度疏松程度,MPS随之显著性下降。随BMD水平的依梯次下降,即骨质疏松程度进行性加重,椎体松质骨显微结构参数发生相应明显变化,存在BMD水平间的显著性差异。广泛的相关性存在于BMD、显微CT参数和螺钉MPS指标之间。其中,螺钉MPS与显微CT扫描所得的骨体积分数（BV/TV）、骨小梁厚度（Tb.Th）和小梁间隙（Tb.Sp）呈高度相关性。结论 随BMD下降,骨组织会同时发生质的退变;螺钉MPS与部分骨显微结构参数高度相关。