Comparison of the predictive values of MRI-based vertebral bone quality scores for the determination of osteoporosis in different diseases.

PURPOSE: The study aimed to examine the consistency of vertebral bone quality (VBQ) scores for assessing osteoporosis across different etiologies and explore the predictive value of various VBQ scores for fragility vertebral fractures. METHODS: Patients with fragility fractures were matched by age and sex to patients with lumbar degeneration. VBQ scores were calculated in T1- and T2-weighted magnetic resonance imaging. Differential analysis of bone quality was performed based on etiology. RESULTS: A total of 96 inpatients were retrospectively enrolled. VBQT1 scores were only sensitive to osteoporotic bone in degenerative group (p < 0.01), failing to identify osteoporosis in fractured group (p > 0.05). For the degenerative group, the area under the curve (AUC) using the VBQT1 scores to differentiate osteoporosis was 0.72. After controlling the confounding variables, only VBQT2 scores were significantly higher in fractured group than degenerative group, with a greater AUC of 0.82 predicting fragility fractures. VBQT1 scores moderately correlated with femoral neck T-scores in degenerative group (r = -0.45, p < 0.01) but not in fractured group (r = -0.24, p > 0.05). VBQT2 scores were not associated with femoral neck T-scores (p > 0.05). CONCLUSION: This study is the first to evaluate the effectiveness of VBQs scores in assessing osteoporosis post-fracture. Only non-fractured patients' bone quality is fully susceptible to VBQT1 scores. While VBQT1 scores may not correlate with fragility fractures, VBQT2 scores present a viable alternative.

What are the differences in paraspinal muscle morphometry among degenerative spondylolisthesis patients, isthmic spondylolisthesis patients, and healthy individuals? A propensity score matching analysis.

PURPOSE: To compare the morphometry of paraspinal muscles in patients with degenerative spondylolisthesis (DS), isthmic spondylolisthesis (IS), and healthy individuals. METHODS: Thirty-seven pairs of DS patients were selected using propensity score matching with IS patients, while 37 healthy individuals matched for age, sex, and BMI were selected as controls. The relative cross-sectional area (rCSA), and relative functional cross-sectional area (rfCSA) of paraspinal muscles were measured, and the degree of fatty infiltration (FI) was calculated. Based on occupational differences, the patients were also divided into worker and farmer groups, and the same measurements were taken on them. RESULTS: At the L3/L4 level, the multifidus (MF) FI was greater in the DS and IS groups than in the control group, the erector spinae (ES) rfCSA was higher in the IS group than in the DS and control groups. At the L4/L5 level, MF rfCSA was smaller in the DS and IS groups than in the control group; ES rfCSA was higher in the IS group than in the DS and control groups. At the L5/S1 level, MF rfCSA was smaller in the DS and IS groups than in the control group; ES rfCSA was higher in the IS group than in the DS group. At the L3/L4, L4/L5 level, MF rfCSA were higher in the worker group than in the farmer group (p < 0.05). CONCLUSION: The morphological changes in paraspinal muscles in patients with DS were dominated by selective atrophy of the MF, while in patients with IS, the morphological changes in paraspinal muscle showed selective atrophy of the MF accompanied by compensatory hypertrophy of the ES. The surgeon should consider the morphological differences in paraspinal muscle between different types of lumbar spondylolisthesis when establishing the appropriate surgical program.

Ideal entry point and trajectory for C2 pedicle screw placement in children: a 3D computed tomography study.

PURPOSE: To identify the ideal entry point for pediatric C2 pedicle screw and to obtain parameters of it for the indication of pediatric atlantoaxial fusion arthrodesis. METHODS: The pediatric cervical CT images were reconstructed into the 3D digital models and the C2 vertebrae were separated. The location of ideal entry point and screw placement related linear and angular parameters were assessed on the 3D digital models. RESULTS: A total of 214 pedicles from 107 C2 digital models were analyzed. The average entry point for C2 was 3.80 ± 2.78 mm medial to the lateral notch (LN) and 2.57 ± 1.70 mm superior to the LN. The average pedicle diameter (PD) was 6.02 ± 1.31 mm, and the average pedicle screw length (PSL) was 25.63 ± 3.46 mm. Statistical differences were found between different sex for PD and PSL (P < 0.05). As patient age increases, using the most lateral and inferior edge of the lateral mass as a reference marker, the entry point tends to move medial and cephalad, when using the LN as a reference marker, the entry point tends to move medial and slightly caudad. Univariate linear regression analysis suggested that these linear parameters were associated with age (P < 0.01). CONCLUSION: In this study, we found that the measurement results of C2 pedicle screw varied based on sex, laterality, and ages for children younger than 18 years. The entry point of the screws facilitating ideal trajectory tends to change in a linear way as a function of age. This information helps the surgeon to establish the specific anatomy related to C2 pedicle screw placement to facilitate fixation in the pediatric patients.

[The electroluminescence spectra of InGan/GaN blue LEDs during aging time].

The luminescence spectra of InGaN/GaN multiple quantum wells light-emitting diodes under low level injection current (<4 mA) during aging process was investigated for the first time. Comparing the electroluminescence (EL) spectra of LEDs before and after aging time it was found that the peak wavelength and the full width at half maximum (FWHM) decreased with stress time and the changes of EL spectrum had two different stages-drastic decrease at the early stress stage and slow decrease later showing the same trend with the output optical power of LEDs, which indicates that the effective polarization electric field of LEDs becomes weak during the aging process and the change has a clear correlation with the increase of the defects in the multiple quantum wells of LEDs. Electrical measurement revealed that junction capacitance (C(j)) under the same junction voltage (V(j) = 1.8 V) and the junction voltage (V(j)) with the same injection current 1 mA calculated by ac small-signal IV method increased along with aging time, which explicates that the carrier density under the same low injection increases as the aging time increases. Analyses indicate that the polarization field in the quantum well is more seriously screened by the increased carriers captured by defects activated during stress time, the weaker effective polarization electric field makes the tilt of the energy band smaller, the energy radiated through the band edge and the density of energy states of the band edge increase which leads to the behaviors of peak wavelength and the FWHM of InGaN/GaN multiple quantum wells LEDs under low level injection current.

Does the sizing of current cervical disc arthroplasty systems match Chinese cervical anatomic dimensions?

Objective: The objectives of this study were to analyze the computed tomography (CT) scan imaging data of the cervical spine from healthy volunteers and to correlate the measurements to the dimensions of current cervical disc arthroplasty systems. Methods: A total of 130 participants (78 males and 52 females) with a mean age of 41.0 years (range 18.0-66.0 years) who had undergone computed tomography scans of the cervical spine were included. The linear parameters of the C3 to C7 levels, including anterior-posterior diameter (AP), middle disc height (DH), anterior disc height (ADH), posterior disc height (PDH) and center mediolateral diameter (ML), were measured. The analysis was conducted comparing different cervical levels, sexes, and age groups. Known dimensions from eight cervical disc arthroplasty systems were compared with the morphologic data. Results: A total of 520 vertebral segments were measured. The mean values for the measured parameters were as follows: anterior-posterior diameter 16.08 ± 1.84 mm, mediolateral diameter 16.13 ± 1.99 mm, anterior disc height 3.88 ± 1.11 mm, disc height 5.73 ± 1.00 mm, posterior disc height 2.83 ± 0.94 mm, and mediolateral diameter/anterior-posterior diameter 1.01 ± 0.13. All parameters except for posterior disc height were significantly different across the different cervical levels (p < 0.05). There were also significant sex differences in terms of the linear parameters. No differences were found in the majority of parameters among the different age groups (p > 0.05), except for anterior-posterior diameter at the C6/7 level. A comparison of the bone dimensions from the study data and the dimensions of the implants indicated the presence of a size mismatch in the currently available cervical disc prostheses. Conclusion: There is a large discrepancy between the cervical anatomical data of Chinese patients and the sizes of currently available prostheses. The dimensions collected in this study could be used to design and develop appropriate disc prostheses for Chinese patients.

Genetic polymorphisms of the TNF-α-308G/A are associated with metabolic syndrome in asthmatic patients from Hebei province, China.

Asthma is a complex inflammatory disease involving the critical actions of several important cytokines. Epidemiological data show that obesity could increase the risk of asthma, and insulin resistance, or metabolic syndrome are an important risk factor for obesity asthma. Some studies identified that upstream of the transcription start site within the TNF-α gene promoter region-308 polymorphism was associated insulin resistance or metabolic disorders, while this site was closely related to asthma. But no research was performed to evaluate the influence of TNF-α-308G/A polymorphism on metabolic syndrome in asthmatic patients. Here, we recruited 248 asthmatic patients, who were separated into asthma with Mets/asthma without Mets groups and 226 matched healthy controls from Hebei Province to evaluate the influence of TNF-α-308G/A polymorphism on metabolic syndrome in asthmatic patients. Single nucleotide polymorphism of TNF-α-308 locus was genotyped using PCR-RFLP. Some biochemical variables were also determined. Our result showed that the genotypic and allelic frequency of rs1800629 did not show significant difference between asthmatic patients and normal controls. However, the frequency of A allele was significantly higher in asthma group with Mets (22.36%) than in controls (15.71%) (P = 0.02; OR = 0.647; 95% CI = 0.447-0.936). After analyzing the relationship between biochemical features of patients and genotype of TNF-α-308G/A, we found levels of LDL cholesterol, TNF-α and insulin, and HOMA-IR were significantly higher in the asthmatic patients carrying the GA and AA genotypes than in the carriers of GG genotype of rs1800629 (P = 0.029, P = 0.022, P = 0.043, respectively). Thus, our data suggested that TNF-α-308G/A variation was related to metabolic phenotype in asthma patients. Furthermore, we first identified TNF-α-308 A allele was the risk factor for asthmatic patients with Mets in Hebei population, China.