Biomechanical assessment of vertebrae with lytic metastases with subject-specific finite element models.

The assessment of risk of vertebral fracture in patients with lytic metastases is challenging, due to the complexity in modelling the mechanical properties of this heterogeneous material. Currently clinical assessment of patients at high risk of fracture is based on the Spinal Instability Neoplastic Score (SINS), which however in many cases does not provide clear guidelines. The goal of this study was to develop a computational approach to provide a comparative biomechanical assessment of vertebrae with lytic lesions with respect to the adjacent controls and highlight the critical vertebrae. The computed tomography images of the thoracolumbar spine of eight patients suffering of vertebral lytic metastases with SINS between 7 and 12 (indeterminate unstable) were analysed. For each patient one or two vertebrae with lytic lesions were modelled and the closest vertebrae without lesions were considered as control. Metastatic vertebrae (N = 12) and controls (N = 18) were converted to subject-specific, heterogeneous, isotropic, nonlinear finite element models for simulating uniaxial compression. Densitometric and mechanical properties were computed for each vertebra. In average, similar mechanical properties were found for vertebrae with lytic lesions and controls (e.g. ultimate force equal to 6.2 ±â€¯2.7 kN for vertebrae with lytic lesions and to 6.2 ±â€¯3.0 kN for control vertebrae). Only in three patients the vertebrae with lytic lesions were found to be mechanically weaker (-19% to -75% difference for ultimate stress) than the controls. In conclusion, in this study we presented an approach to estimate the mechanical competence of vertebrae with lytic metastases. It remains to be investigated in a clinical study if this method, together with the SINS, can better classify patients with vertebrae with lytic lesions at high risk of fracture.

Experiences with PMMA cement as a stand-alone intervertebral spacer: Percutaneous cement discoplasty in the case of vacuum phenomenon within lumbar intervertebral discs.

BACKGROUND: The treatment of symptomatic degenerative disc disease of the lumbar spine in elderly patients by standard surgical methods is often limited due to severe comorbidities (e.g., cardiopulmonary disease, hypertonia, diabetes). Minimally invasive procedures are more acceptable in this population, since they reduce surgical morbidity and the risk of complications. The percutaneous cement discoplasty (PCD) technique was introduced by the authors to treat dynamic (and angular) instability of the symptomatic lumbar segment by injecting bone cement (polymethylmethacrylate, PMMA) into the disc spaces showing vacuum phenomena via a posterolaterally positioned Jamshidi needle. The aim of this article is to describe the indication, method, and clinical results of PCD. METHOD: A total of 81 patients were treated with PCD in a tertiary care referral center over a 6-year period. The current study includes the first group of 47 consecutive patients to complete a pre- and postoperative questionnaire booklet regarding leg and back pain using the visual analog scale (VAS) and the Oswestry disability index (ODI) questionnaire. RESULTS: A total of 130 discs in these 47 patients were treated with PCD. The majority of patients reported a reduction in their lower back and leg pain (69% and 66%, respectively; p < 0.02) postoperatively. At 6-month follow-up, 61% of patients had a minimum 10-point reduction in their ODI scores (p < 0.01). CONCLUSION: Elderly patients with symptomatic dynamic foraminal stenosis and vacuum phenomenon in the intervertebral disc are suitable candidates for PCD, particularly if they represent high-risk patients for open surgery.

[Experiences with PMMA cement as a stand-alone intervertebral spacer. Percutaneous cement discoplasty in the case of vacuum phenomenon within lumbar intervertebral discs]. / Erfahrungen mit PMMA-Zement als intervertebraler Stand-alone-Platzhalter. Perkutane Zement-Diskoplastie bei Vakuumphänomen der lumbalen Bandscheiben.

BACKGROUND: The treatment of symptomatic degenerative disc disease of the lumbar spine in elderly patients by standard surgical methods is often limited due to severe comorbidities (e.g., cardiopulmonary disease, hypertonia, diabetes). Minimally invasive procedures are more acceptable in this population, since they reduce surgical morbidity and the risk of complications. The percutaneous cement discoplasty (PCD) technique was introduced by the authors to treat dynamic (and angular) instability of the symptomatic lumbar segment by injecting bone cement (polymethylmethacrylate, PMMA) into the disc spaces showing vacuum phenomena via a posterolaterally positioned Jamshidi needle. The aim of this article is to describe the indication, method, and clinical results of PCD. METHOD: A total of 81 patients were treated with PCD in a tertiary care referral center over a 6-year period. The current study includes the first group of 47 consecutive patients to complete a pre- and postoperative questionnaire booklet regarding leg and back pain using the visual analog scale (VAS) and the Oswestry disability index (ODI) questionnaire. RESULTS: A total of 130 discs in these 47 patients were treated with PCD. The majority of patients reported a reduction in their lower back and leg pain (69 and 66 %, respectively; p < 0.02) postoperatively. At 6-month follow-up, 61 % of patients had a minimum 10-point reduction in their ODI scores (p < 0.01). CONCLUSION: Elderly patients with symptomatic dynamic foraminal stenosis and vacuum phenomenon in the intervertebral disc are suitable candidates for PCD, particularly if they represent high-risk patients for open surgery.

Reduction of healthcare-associated infections in a long-term care brain injury ward by replacing regular linens with biocidal copper oxide impregnated linens.

BACKGROUND: Contaminated textiles in hospitals contribute to endogenous, indirect-contact, and aerosol transmission of nosocomial related pathogens. Copper oxide impregnated linens have wide-spectrum antimicrobial, antifungal, and antiviral properties. Our aim was to determine if replacing non-biocidal linens with biocidal copper oxide impregnated linens would reduce the rates of healthcare-associated infections (HAI) in a long-term care ward. METHODS: We compared the rates of HAI in two analogous patient cohorts in a head injury care ward over two 6-month parallel periods before (period A) and after (period B) replacing all the regular non-biocidal linens and personnel uniforms with copper oxide impregnated biocidal products. RESULTS: During period B, in comparison to period A, there was a 24% reduction in the HAI per 1000 hospitalization-days (p<0.05), a 47% reduction in the number of fever days (>38.5°C) per 1000 hospitalization-days (p<0.01), and a 32.8% reduction in total number of days of antibiotic administration per 1000 hospitalization-days (p<0.0001). Accordingly there was saving of approximately 27% in costs of antibiotics, HAI-related treatments, X-rays, disposables, labor, and laundry, expenses during period B. CONCLUSIONS: The use of biocidal copper oxide impregnated textiles in a long-term care ward may significantly reduce HAI, fever, antibiotic consumption, and related treatment costs.

New approach to analyze genetic and clinical data in bisphosphonate-induced osteonecrosis of the jaw.

OBJECTIVES: Osteonecrosis of the jaw (ONJ) is a major complication associated with long-term use of bisphosphonates (BP). We aimed to investigate the effect of CYP2C8 rs1934951 SNP and its relationship to a number of clinical and biochemical factors in 46 Hungarian subjects with bisphosphonate-induced ONJ. METHODS: Blood samples were collected from each subject and genomic DNA was extracted. SNP analysis of CYP2C8 gene was carried out by predesigned TaqMan primer/probe sets. The genetic data together with clinical and biochemical variables were evaluated by chi-square test, logistic regression, and principal component analysis (PCA). RESULTS: The risk of mandibular localization of ONJ was 19.2-fold higher in subjects with AG genotype than in normal GG genotype. PCA revealed strong positive correlations between maxillar localization of ONJ and a group of variables including intravenous BP application and serum lipid markers. Mandibular localization of ONJ was correlated positively with serum calcium, 25-hydroxy-vitamin D and PTH levels, oral BP application, and the length of BP therapy. The degree of the disease and the number of recurrences were correlated with the application of hormone-deprivation therapy for breast cancer patients. CONCLUSION: The statistical approach applying PCA to our data may contribute to the better understanding of factors playing role in the development of bisphosphonate-induced ONJ.

LCT 13910 C/T polymorphism, serum calcium, and bone mineral density in postmenopausal women.

SUMMARY: LCT 13910 CC genotype is associated with lactose intolerance, a condition often resulting in reduced milk intake. Women with the CC genotype were found to have decreased serum calcium and reduced bone mineral density. INTRODUCTION: The CC genotype of the 13910 C/T polymorphism of the LCT gene is linked to lactose intolerance and low calcium intake. METHODS: We studied 595 postmenopausal women, including 267 osteoporotic, 200 osteopenic, and 128 healthy subjects. Genotyping, osteodensitometry, and laboratory measurements were carried out. RESULTS: Frequency of aversion to milk consumption was 20% for CC genotype and 10% for TT + TC genotypes (p = 0.03). The albumin-adjusted serum calcium was 2.325 +/- 0.09 mmol/L for CC genotype and 2.360 +/- 0.16 mmol/L for TT + TC genotypes (p = 0.031). Bone mineral density (BMD; Z score) was lower in the CC than TT + TC genotypes, respectively, at the radius (0.105 +/- 1.42 vs 0.406 +/- 1.32; p = 0.038), at the total hip (-0.471 +/- 1.08 vs -0.170 +/- 1.09; p = 0.041), and at the Ward's triangle (-0.334 +/- 0.87 vs -0.123 +/- 0.82; p = 0.044). CONCLUSION: LCT 13910 C/T polymorphism is associated with decreased serum calcium level and lower BMD in postmenopausal women.

CYP3A7*1C polymorphism, serum dehydroepiandrosterone sulfate level, and bone mineral density in postmenopausal women.

The CYP3A7 enzyme metabolizes some steroid hormones, including dehydroepiandrosterone sulfate (DHEAS). The age-related decline of serum DHEAS levels is believed to contribute to osteoporosis. Previously, the CYP3A7*1C polymorphism has been shown to cause a persistent high CYP3A7 enzyme activity, resulting in lower levels of DHEAS in men. We hypothesized that the CYP3A7*1C polymorphism might contribute to bone loss through decreased levels of serum DHEAS in postmenopausal women. Postmenopausal women (n = 319) were divided into two subgroups: 217 with osteoporosis and 102 healthy controls. Genotyping, serum DHEAS measurement, and osteodensitometry of the lumbar spine and femoral neck were carried out in all subjects. Homozygous CYP3A7*1C carriers had significantly lower BMD at the lumbar spine compared to wild types (T score -3.27 +/- 1.02 in CYP3A7*1C homozygous mutants vs. -1.35 +/- 1.53 in wild types, P = 0.041). This association remained significant after adjustment for menopausal age, serum DHEAS level, alcohol consumption, steroid intake, smoking habits, and previous fractures. No association was found between genotypes and serum DHEAS levels in the total study population or in the subgroups. Serum DHEAS levels correlated positively with bone mineral density at the lumbar spine (r = 0.59, P = 0.042) after correction for age. Our data suggest that the CYP3A7 polymorphism might have an influence on bone mass at the lumbar spine independently of serum DHEAS concentrations.