Nanoparticle elasticity regulates the formation of cell membrane-coated nanoparticles and their nano-bio interactions.

Cell membrane-coated nanoparticles are emerging as a new type of promising nanomaterials for immune evasion and targeted delivery. An underlying premise is that the unique biological functions of natural cell membranes can be conferred on the inherent physiochemical properties of nanoparticles by coating them with a cell membrane. However, the extent to which the membrane protein properties are preserved on these nanoparticles and the consequent bio-nano interactions are largely unexplored. Here, we synthesized two mesenchymal stem cell (MSC) membrane-coated silica nanoparticles (MCSNs), which have similar sizes but distinctly different stiffness values (MPa and GPa). Unexpectedly, a much lower macrophage uptake, but much higher cancer cell uptake, was found with the soft MCSNs compared with the stiff MCSNs. Intriguingly, we discovered that the soft MCSNs enabled the forming of a more protein-rich membrane coating and that coating had a high content of the MSC chemokine CXCR4 and MSC surface marker CD90. This led to the soft MCSNs enhancing cancer cell uptake mediated by the CD90/integrin receptor-mediated pathway and CXCR4/SDF-1 pathways. These findings provide a major step forward in our fundamental understanding of how the combination of nanoparticle elasticity and membrane coating may be used to facilitate bio-nano interactions and pave the way forward in the development of more effective cancer nanomedicines.

Evaluation of a continuous-time random-walk diffusion model for the differentiation of malignant and benign breast lesions and its association with Ki-67 expression.

The purpose of the current study was to evaluate the performance of a continuous-time random-walk (CTRW) diffusion model for differentiating malignant and benign breast lesions and to consider the potential association between CTRW parameters and the Ki-67 expression. Sixty-four patients (46.2 ± 11.4 years) with breast lesions (29 malignant and 35 benign) were evaluated with the CTRW model, intravoxel incoherent motion model, and diffusion-weighted imaging. Echo planar diffusion-weighted imaging was conducted using 13 b-values (0-3000 s/mm2 ). Three CTRW model parameters, including an anomalous diffusion coefficient Dm , and two parameters related to temporal and spatial diffusion heterogeneity, α and ß, respectively, were obtained, and had MRI b-values of 0-3000 s/mm2 . Receiver operating characteristic (ROC) analysis was conducted to determine the sensitivity, specificity, and diagnostic accuracy of CTRW parameters for differentiating malignant from benign breast lesions. In malignant breast lesions, the CTRW parameters Dm , α, and ß were significantly lower than the corresponding parameters of benign breast lesions. In the malignant breast lesion group, the CTRW parameter Dm was significantly lower in high Ki-67 expression than in low Ki-67 expression. In ROC analysis, the combination of CTRW parameters (Dm , α, ß) demonstrated the highest area under the curve value (0.985) and diagnostic accuracy (94.23%) in differentiating malignant and benign breast lesions. The CTRW model effectively differentiated malignant from benign breast lesions. The CTRW diffusion model offers a new way for noninvasive assessment of breast malignancy and better understanding of the proliferation of malignant lesions.

Impacts of climate change on herpetofauna diversity in the Qinghai-Tibetan Plateau.

Although numerous studies on the impacts of climate change on biodiversity have been published, only a handful are focused on the intraspecific level or consider population-level models (separate models per population). We endeavored to fill this knowledge gap relative to the Qinghai-Tibetan plateau (QTP) by combining species distribution modeling (SDMs) with population genetics (i.e., population-level models) and phylogenetic methods (i.e., phylogenetic tree reconstruction and phylogenetic diversity analyses). We applied our models to 11 endemic and widely distributed herpetofauna species inhabiting high elevations in the QTP. We aimed to determine the influence of environmental heterogeneity on species' responses to climate change, the magnitude of climate-change impacts on intraspecific diversity, and the relationship between species range loss and intraspecific diversity losses under 2 shared socioeconomic pathways (SSP245 and SSP585) and 3 future periods (2050s, 2070s, and 2090s). The effects of global climatic change were more pronounced at the intraspecific level (22% of haplotypes lost and 36% of populations lost) than the morphospecies level in the SSP585 climate change scenario. Maintenance of genetic diversity was in general determined by a combination of factors including range changes, species genetic structure, and the part of the range predicted to be lost. This is owing to the fact that the loss and survival of populations were observed in species irrespective of the predicted range changes (contraction or expansion). In the southeast (mountainous regions), climate change had less of an effect on range size (>100% in 3 species) than in central and northern QTP plateau regions (range size <100% in all species). This may be attributed to environmental heterogeneity, which provided pockets of suitable climate in the southeast, whereas ecosystems in the north and central regions were homogeneous. Generally, our results imply that mountainous regions with high environmental heterogeneity and high genetic diversity may buffer the adverse impacts of climate change on species distribution and intraspecific diversity. Therefore, genetic structure and characteristics of the ecosystem may be crucial for conservation under climate change.

Impactos del cambio climático sobre la diversidad de herpetofauna en la meseta Qinghai-Tíbet Región Aunque se han publicado numerosos estudios sobre los impactos del cambio climática en la biodiversidad, son muy pocos los que se enfocan en el nivel intraespecífico o que consideran modelos a nivel poblacional (modelos separados por población). Intentamos cerrar este vacío de conocimiento en relación con la meseta Qinghai-Tíbet (MQT) con la combinación entre modelos de distribución de especies (MDE) y genética poblacional (modelos a nivel poblacional) y métodos filogenéticos (reconstrucción de árboles filogenéticos y análisis de diversidad filogenética). Aplicamos nuestros modelos a once especies endémicas de herpetofauna con distribución amplia en las elevaciones más altas de la MQT. Nos planteamos determinar la influencia de la heterogeneidad de las especies sobre la respuesta de las especies al cambio climático, la magnitud de los impactos del cambio climático sobre la diversidad intraespecífica y la relación entre la pérdida de distribución de la especie y las pérdidas de diversidad intraespecífica bajo dos vías socioeconómicas (SSP245 y SSP585) y tres periodos del futuro (2050s, 2070s y 2090s). Los efectos del cambio climático global fueron más pronunciados a nivel intraespecífico (22% de pérdida en los haplotipos y 36% en las poblaciones) que al nivel morfoespecie en el escenario de cambio climático SSP585. El mantenimiento de la diversidad genética casi siempre estuvo determinado por una combinación de factores que incluyen cambios en la distribución, estructura genética de las especies y la parte de la distribución que se pronosticó se perdería. Esto se debe a que observamos la pérdida y supervivencia de las poblaciones sin importar los cambios pronosticados en la distribución (contracción o expansión). En las regiones montañosas del sureste, el cambio climático tuvo un efecto menor sobre la distribución (>100% en tres especies) comparado con las regiones de la meseta central y del norte de la MQT (distribución <100% en todas las especies). Esto puede atribuirse a la heterogeneidad ambiental, la cual proporciona recovecos de clima adecuado en el sureste, mientras que los ecosistemas en las regiones central y norte fueron homogéneos. De manera general, nuestros resultados implican que las regiones montañosas con una elevada heterogeneidad ambiental y una gran diversidad genética podrían reducir los impactos adversos del cambio climático sobre la distribución de las especies y la diversidad intraespecífica. Por lo tanto, la estructura genética y las características del ecosistema pueden ser cruciales para conservar bajo el cambio climático.

Impact of lumbar fusion on spinopelvic sagittal alignment from standing to sitting position: which factor is associated with postoperative functional limitations due to lumbar stiffness?

PURPOSE: To investigate the impact of lumbar fusion on spinopelvic sagittal alignment from standing to sitting position and the influencing factors of postoperative functional limitations due to lumbar stiffness. METHODS: A total of 107 patients who undertook posterior lumbar interbody fusion were included. Patients were divided into two groups: Group A (lumbosacral fusion; n = 43) and Group B (floating fusion; n = 64). Spinopelvic parameters in standing and sitting position including pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), lumbar lordosis (LL), fusion segment lordosis (FSL), upper residual lordosis (URL), lower residual lordosis (LRL), thoracic kyphosis (TK), thoracolumbar kyphosis (TLK), sagittal vertical axis (SVA) and T1 pelvic angle (TPA) were measured before and after lumbar fusion. The Lumbar Stiffness Disability Index (LSDI) was used to assess functional limitations due to lumbar stiffness. RESULTS: Accompanied by increased postoperative LSDI, the values of changes from standing to sitting (∆) were reduced in some parameters compared with the preoperative values. ∆PT and ∆SS significantly decreased in both two groups. In Group A, ∆LL significantly decreased with increased ∆URL. In Group B, ∆LL, ∆URL and ∆LRL showed no significant difference before and after surgery. Multiple linear regression analysis showed that age and ∆PT independently influenced the postoperative LSDI in Group A. CONCLUSION: After lumbar fusion, changes of lumbopelvic sagittal parameters from standing to sitting would be restricted. Adjacent segment lordosis could partially compensate for this restriction. For patients with lumbosacral fusion, postoperative functional limitations due to lumbar stiffness were related to age and the postoperative ∆PT from standing to sitting.

Relationship Between Emotional Eating and Weight Loss Effect of the 211 Diet Body Weight Management Method in Obese Women of Childbearing Age.

Purpose: To explore the relationship between emotional eating behavior and the weight loss effect of the 211 Diet body weight management method in obese women of childbearing age. Methods: From March 2021 to November 2021, 33 obese women of childbearing age who were recommended by gynecologists to achieve weight management were selected from the gynecological outpatient department of The Affiliated Hospital of Guizhou Medical University via the target sampling method. The participants who met all the study inclusion criteria and did not meet any of the exclusion criteria underwent a 40-day 211 Diet body weight management program. Body mass index (BMI) was collected on the day before the formal start and the first day after 40 days of weight loss. The 7-item Generalized Anxiety Disorder Scale (GAD-7), 9-item Patient Health Questionnaire (PHQ-9) and Weight Efficacy Lifestyle Questionnaire-Short Form (WEL-SF) were employed to evaluate participants' anxiety, depression and dietary self-efficacy before and after weight loss. On the day before the formal start of the program, the Dutch Eating Behaviour Questionnaire (DEBQ) was used to investigate the causes of previous induced eating. Results: The weight of the participants before weight loss was positively correlated with the previous emotional eating scores (r = 0.37; P < .05); after 40 days of weight loss, body weight and BMI were significantly lower than before weight loss (P < .05); BMI reduction value = 1.97 + 0.16*PHQ9 D-value (R2 = 0.35, B = 0.16; P < .001); there was no correlation between WEL-SF scores before and after weight loss (P > .05); WEL-SF scores D-value was positively correlated with previous emotional eating scores (r = 0.41; P < .05), WEL-SF D-value = -22.09 + 1.13*emotional eating (R2=0.16, B=1.13; P < .05); there was no difference among WEL-SF, GAD-7 and PHQ-9 scores before and after weight loss (P > .05). Conclusion: The participants' relatively higher body weight before weight loss was related to their previous relatively more significant emotional eating behaviors. In obese women of childbearing age with more obvious previous emotional eating behaviors, the 211 Diet body weight management method may be more beneficial for weight loss.

A novel refined classification system for type 2 diabetes in adults: A Chinese retrospective cohort study.

AIMS: We propose a simple type 2 diabetes mellitus (T2DM) classification method based on fasting C-peptide (FCP) levels and examined its feasibility and validity. METHODS: Adult T2DM patients first diagnosed in our tertiary care centre from January 2009 to January 2020 were included. Patients were followed until January 2021; their clinical characteristics, chronic complications, treatment regimen, and glycaemic control were compared. RESULTS: In total, 5644 T2DM patients were included. Three subgroups were established based on FCP levels: subtype T1 (FCP ≤ 1.0 µg/L), 1423 patients (25.21%); subtype T2 (FCP 1.0-2.5 µg/L), 2914 patients (51.63%); and subtype T3 (FCP ≥ 2.5 µg/L), 1307 patients (23.16%). T1 was characterised by older age, lower body mass indices, higher initial glycosylated haemoglobin (HbA1c) levels, and the lowest homoeostatic model assessment 2 estimates of ß-cell function (HOMA2-ß) and HOMA2-insulin resistance at baseline. The T3 group's clinical characteristics were opposite to those of T1. T3 patients showed higher incidence rates and risks of diabetic kidney disease, diabetic peripheral vascular disease, and non-alcoholic fatty liver, while the risks of diabetic retinopathy and diabetic peripheral neuropathy were highest in T1. Insulin, glycosidase inhibitors, and thiazolidinedione were the most frequently used drugs, but the use of metformin, dipeptidyl peptidase-4 inhibitor, and insulin secretagogue drugs was slightly lower in T1. T1 maintained higher HbA1c levels throughout follow-up. Overall HbA1c fluctuations were more significant in T3 than in T1 and T2. CONCLUSIONS: The new adult T2DM classification is simple and clear and will help classify different T2DM clinical characteristics and guide treatment plans.

2022 Expert consensus on the use of laser ablation for papillary thyroid microcarcinoma.

OBJECTIVE: With the aim of standardizing and improving the use of ultrasound-guided PLA on PTMC, a panel of experts from China and Italy, jointly issued this expert consensus on the clinical use of PLA for low-risk PTMC. METHODS: This expert consensus was developed by Chinese and Italian experts who have specific competence and expertise in this area. An evidence-based approach combining the knowledge and practical experience of the panelists was utilized. RESULTS: Twenty-six expert consensus recommendations were developed, spanning topics including the indications and contraindications of PLA for PTMC, physician training, preoperative preparation of patients, intraoperative technical procedures, possible complications, efficacy assessment, follow-up strategy, the approach to new PTMC and metastatic lymph nodes after treatment, thyroid-stimulating hormone inhibition therapy, and quality control of the entire procedure. CONCLUSION: We summarized practical recommendations about standardized and improved PLA treatment for PTMC.

Correlation between lordosis distribution index, lordosis tilt, and occurrence of proximal junctional kyphosis following surgery for adult degenerative scoliosis.

PURPOSE: This study aimed to evaluate the effect of postoperative reciprocal progression of Lordosis tilt (LT), Lordosis distribution index (LDI) and occurrence of Proximal junctional kyphosis (PJK) following surgery for Degenerative lumbar scoliosis (DLS). METHODS: A total of 122 consecutive patients with ADS were treated with correction of deformity and followed up for a minimum of 2 years. Spinopelvic parameters were measured preoperatively, postoperatively, and at the latest follow-up. The Japanese Orthopaedic Association score, Oswestry Disability Index, and visual analog scale scores were measured at the latest follow-up. Associations between LT, LDI, and PJK were analyzed using receiver operating characteristic analyses. RESULTS: The prevalence of PJK in the present study was 24.6%. The outcomes of patients with PJK were significantly worse than those of patients without PJK. Postoperative reciprocal progression in LT and LDI with lumbar lordosis restorative surgery was observed. Preoperative risk factors for PJK were older age, larger LT, and larger Cobb angle of the curves. Postoperative risk factors for PJK included postoperative LT and postoperative Cobb angle of the curves, which were smaller than those preoperatively. We found a strong correlation between postoperative LT and Cobb angle of the curves resulting in PJK. Patients with LT < - 8° were at a higher risk of PJK. CONCLUSIONS: LT can be used to predict the occurrence of PJK in patients undergoing surgery for DLS. Appropriate postoperative LT is crucial for preventing the progression of PJK.

The relationship between S1 screw loosening and postoperative outcome in patients with degenerative lumbar scoliosis.

BACKGROUND: When choosing S1 as the lowest level of instrumentation, there are many complications may come out such as S1 screw loosening. Facing this problem, there has been various techniques for the protection of S1 screw including sacropelvic fixation, bicortical or tricortical insertion of S1 screw. OBJECTIVE: This study aimed to explore the risk factors for the S1 screw loosening, then to demonstrate the relationship between S1 screw loosening and postoperative outcome for patients with degenerative lumbar scoliosis (DLS). METHODS: Patients who underwent lumbosacral fixation for DLS were evaluated retrospectively. They were divided into two groups according to the S1 pedicle screw at the follow-up. Age, gender, bone mineral density, body mass index, history of smoking, the number of instrumented levels, comorbidities, complications and radiological parameters were collected. We established logistic regression analysis to determine independent risk factors for S1 screw loosening and multiple linear regression to identify whether S1 screw loosening would influence postoperative clinical outcome. RESULTS: S1 screw loosening rate was up to 41.0% (32/78). Patients were older in the S1 screw loosening group than those in the control group (P < 0.05). Compared with the control group, the rate of osteoporosis was higher in screw loosening group than that in the control group (P < 0.05). Older age and osteoporosis were independent risk factors for S1 screw loosening (P < 0.05). In the screw loosening group, the rate of hypertension was higher than that in the control group (P < 0.05). The relationship of S1 screw loosening and ODI was not significant in the multiple linear regression (P > 0.05). The clinical outcome was similar in the S1 screw loosening group and control group (P > 0.05). CONCLUSION: Older age and osteoporosis are independent risk factors for the S1 screw loosening. Patients with complication of S1 screw loosening are not always along with worse clinical outcome. We should consider potential benefit, complications and medical cost when choosing the lowest instrumented vertebrae for patients with DLS.

Paraspinal muscle characteristics on MRI in degenerative lumbar spine with normal bone density, osteopenia and osteoporosis: a case-control study.

BACKGROUND: To investigate the difference of paraspinal muscles in patients with normal bone density, osteopenia and osteoporosis. METHODS: Patients undergoing surgery for lumbar spinal stenosis were included. Thirty-eight patients with osteoporosis were matched to patients with osteopenia and patients with normal bone density in a 1:1 manner according to WHO criteria. Dual-energy X-ray absorptiometry (DXA) scans and lumbar CT were performed preoperatively to measure the BMD of lumbar, femur and hip and HU values of L1-L4 respectively. The relative total cross-sectional area (rTCSA) and fat infiltration (FI) of multifidus (MF) and erector spinae (ES), and the relative functional CSA (rFCSA) of psoas major (PS) were measured at L4-5 and L5-S level on preoperative MRI. RESULTS: Osteoporotic patients showed lower BMI, higher MF FI and higher ES FI when compared with normal bone density group (25.57 ± 3.71 vs 27.46 ± 3.11; 0.38 ± 0.1 vs 0.32 ± 0.08; 0.33 ± 0.1 vs 0.28 ± 0.08; all adjusted p < 0.05). Both the MF FI and ES FI were significantly correlated with lumbar T-score (r = - 0.223, p < 0.05; r = - 0.208, p < 0.05) and the averaged lumbar HU value (r = - 0.305, p < 0.01; r = - 0.239, p < 0.05). CONCLUSIONS: Osteoporosis and paraspinal muscle degeneration might interact with each other and coexist in patients with degenerative lumbar diseases. It is recommended that the paraspinal muscle degeneration should be considered simultaneously when finding a patient with low bone mass before surgery.

Fat infiltration of paraspinal muscles as an independent risk for bone nonunion after posterior lumbar interbody fusion.

BACKGROUND: The prognosis value of paraspinal muscle degeneration on clinical outcomes has been revealed. However no study has investigated the effect of the fat infiltration (FI) of paraspinal muscles on bone nonunion after posterior lumbar interbody fusion (PLIF). METHODS: Three hundred fifty-one patients undergoing PLIF for lumbar spinal stenosis with 1-year follow-up were retrospectively identified. Patients were categorized into bone union (n = 301) and bone nonunion (n = 50) groups based on dynamic X-ray at 1-year follow-up. The relative total cross-sectional area (rTCSA) and FI of multifidus (MF) and erector spinae (ES), and the relative functional CSA (rFCSA) of psoas major (PS) were measured on preoperative magnetic resonance imaging. RESULTS: The nonunion group had a significantly higher MF FI and a higher ES FI and a smaller MF rTCSA than the union group (p = 0.001, 0.038, 0.026, respectively). Binary logistic regression revealed that MF FI (p = 0.029, odds ratio [OR] = 1.04), lumbosacral fusion (p = 0.026, OR = 2193) and length of fusion (p = 0.001, OR = 1.99) were independent factors of bone nonunion. In subgroup analysis, in one or two-level fusion group, the patients with nonunion had a higher MF FI and a higher ES FI than those of the patients with union (all p < 0.05). Similarly, in lumbosacral fusion group, the patients with nonunion had a higher MF FI and a higher ES FI than those of the patients with union (all p < 0.05). The logistic regressions showed that MF FI remained an independent factor of bone nonunion both in the patients with one or two-level fusion (p = 0.003, OR = 1.074) and in the patients with lumbosacral fusion (p = 0.006, OR = 1.073). CONCLUSIONS: Higher fatty degeneration was strongly associated with bone nonunion after PLIF. Surgeons should pay attention to the FI of paraspinal muscles when performing posterior surgery for patients, especially those who need short-segment fusion or to extend fusion to S1.

A novel surgical planning system using an AI model to optimize planning of pedicle screw trajectories with highest bone mineral density and strongest pull-out force.

OBJECTIVE: The purpose of this study was to evaluate the ability of a novel artificial intelligence (AI) model in identifying optimized transpedicular screw trajectories with higher bone mineral density (BMD) as well as higher pull-out force (POF) in osteoporotic patients. METHODS: An innovative pedicle screw trajectory planning system called Bone's Trajectory was developed using a 3D graphic search and an AI-based finite element analysis model. The preoperative CT scans of 21 elderly osteoporotic patients were analyzed retrospectively. The AI model automatically calculated the number of alternative transpedicular trajectories, the trajectory BMD, and the estimated POF of L3-5. The highest BMD and highest POF of optimized trajectories were recorded and compared with AO standard trajectories. RESULTS: The average patient age and average BMD of the vertebral bodies were 69.6 ± 7.8 years and 55.9 ± 17.1 mg/ml, respectively. On both sides of L3-5, the optimized trajectories showed significantly higher BMD and POF than the AO standard trajectories (p < 0.05). On average, the POF of optimized trajectory screws showed at least a 2.0-fold increase compared with AO trajectory screws. CONCLUSIONS: The novel AI model performs well in enabling the selection of optimized transpedicular trajectories with higher BMD and POF than the AO standard trajectories.

The role of ceRNA-mediated diagnosis and therapy in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death worldwide due to its high degree of malignancy, high incidence, and low survival rate. However, the underlying mechanisms of hepatocarcinogenesis remain unclear. Long non coding RNA (lncRNA) has been shown as a novel type of RNA. lncRNA by acting as ceRNA can participate in various biological processes of HCC cells, such as tumor cell proliferation, migration, invasion, apoptosis and drug resistance by regulating downstream target gene expression and cancer-related signaling pathways. Meanwhile, lncRNA can predict the efficacy of treatment strategies for HCC and serve as a potential target for the diagnosis and treatment of HCC. Therefore, lncRNA serving as ceRNA may become a vital candidate biomarker for clinical diagnosis and treatment. In this review, the epidemiology of HCC, including morbidity, mortality, regional distribution, risk factors, and current treatment advances, was briefly discussed, and some biological functions of lncRNA in HCC were summarized with emphasis on the molecular mechanism and clinical application of lncRNA-mediated ceRNA regulatory network in HCC. This paper can contribute to the better understanding of the mechanism of the influence of lncRNA-mediated ceRNA networks (ceRNETs) on HCC and provide directions and strategies for future studies.

Sagittal Spinal and Pelvic Alignment in Middle-Aged and Older Men and Women in the Natural and Erect Sitting Positions: A Prospective Study in a Chinese Population.

BACKGROUND This prospective study aimed to compare the sagittal spinopelvic parameters in the erect and natural sitting positions in healthy middle-aged and older men and women in a Chinese population. MATERIAL AND METHODS Ninety healthy middle-aged and older men and women underwent lateral whole spinal radiography in the natural and erect sitting positions. The  radiographic sagittal spinopelvic parameters were measured. They included the sagittal vertical axis (SVA), the T1 pelvic angle (TPA), the pelvic incidence (PI), the pelvic tilt (PT), the sacral slope (SS), thoracic kyphosis (TK), thoracolumbar kyphosis (TLK), the T1 slope (T1S), cervical lordosis (CL), and lumbar lordosis (LL). RESULTS In the natural sitting position, LL decreased by 14.5°, TK and TLK increased by 3.2° and 2.5°, respectively, PT increased by 10.3°, T1S increased by 6.9°, and CL increased by 3.4° compared with the erect position. In the natural sitting position, the mean forward-moving SVA was 33.4 mm, and the C2-C7 SVA was 6.1 mm. Men had a larger LL and smaller PT than the women when sitting in the erect position, and a greater TK, T1S, and C2-C7 SVA than women when sitting in the natural position. CONCLUSIONS In the natural sitting position, a reduction in LL was associated with TK, SVA and PT increased, and there were differences between men and women. The characteristics of spinopelvic alignment in healthy older adults should be considered when planning corrective spinal surgery.

Hounsfield units value is a better predictor of pedicle screw loosening than the T-score of DXA in patients with lumbar degenerative diseases.

PURPOSE: To compare the performance of using Hounsfield units (HU) value derived from computed tomography and T-score of dual-energy X-ray absorptiometry (DXA) to predict pedicle screw loosening. METHODS: We reviewed 253 patients aged ≥ 50 years undergoing pedicle screw fixation for lumbar degenerative diseases (LDD). The evaluation of screw loosening: radiolucent zones of ≥ 1 mm thick in X-ray. The criterion for osteoporosis: the lowest T-score ≤ - 2.5. The average HU value of L1-L4 was used to represent lumbar bone mineral density (BMD). The area under receiver operating characteristics curve (AUC) was used to evaluate the performance of predicting screw loosening. RESULTS: One patient underwent reoperation for screw loosening at 9 months follow-up. At 12 months follow-up, the loosening rate was 30.6% (77/252) in the remaining 252 patients. Osteoporotic patients had higher loosening rate than non-osteoporotic patients (39.3% vs. 25.8%, P = 0.026). The T-score showed no significant difference between loosening group and non-loosening group (- 2.1 ± 1.5 vs. - 1.7 ± 1.6, P = 0.074), and so is the lowest lumbar BMD of DXA (0.83 ± 0.16 g/cm2 vs. 0.88 ± 0.19 g/cm2, P = 0.054). The HU value was lower in the loosening group (106.8 ± 34.4 vs. 129.8 ± 45.7, P < 0.001). The HU value (OR, 0.980; 95%CI 0.968-0.993; P = 0.002) was the independent influencing factor of screw loosening. The AUC of predicting screw loosening was 0.666 (P < 0.001) for HU value and 0.574 (P = 0.062) for T-score. CONCLUSIONS: HU value is a better predictor of pedicle screw loosening than T-score of DXA in patients aged ≥ 50 years with LDD. We should not only focus on the DXA measurements when making surgical plans concerning lumbar fixation. These slides can be retrieved under Electronic Supplementary Material.

Age-based normal sagittal alignment in Chinese asymptomatic adults: establishment of the relationships between pelvic incidence and other parameters.

PURPOSE: To investigate the age-based normal values of sagittal parameters and establish the relationships between them in Chinese population. METHOD: Two hundred eighteen asymptomatic adult volunteers were included in this cross-sectional study. The whole spine standing radiograph was taken from them, and the parameters including sagittal vertical axis (SVA), T1 pelvic angle (TPA), global tilt (GT), spino-sacral angle, lumbar lordosis (LL), thoracic kyphosis (TK), T1 slope (T1S), cervical lordosis (CL), C2-C7SVA, pelvic tilt (PT), sacral slop (SS) and pelvic incidence (PI) were measured. The gender differences in sagittal alignment were compared. Pearson correlation was calculated, and a linear regression analysis was used to establish the relation between PI and other parameters. RESULTS: The average values of PI, LL, TPA and GT were 46.2°, 48.2°, 7.8° and 10.6°, respectively, in this cohort. SVA, GT, TPA, TK, T1S, CL and PT significantly increased with age (p < 0.05). The females presented smaller T1S, C2-C7SVA and larger PI, PT than the males. The relationships between PI and TPA, GT, SS, LL could be presented as TPA = 0.411 * PI - 11.2 (R2 = 0.328, p < 0.001), GT = 0.483 * PI - 11.7 (R2 = 0.297, p < 0.001), SS = 0.354 * PI + 16.1 (R2 = 0.203, p < 0.001), LL = 0.588 * PI + 21.0 (R2 = 0.267, p < 0.001), respectively. CONCLUSION: The normal values of sagittal parameters were presented and changed with age in Chinese asymptomatic population. The gender differences existed in sagittal parameters. The relationships between PI and other parameters were established which could be used for further research. These slides can be retrieved under Electronic Supplementary Material.

Characteristics of vertebral CT Hounsfield units in elderly patients with acute vertebral fragility fractures.

OBJECTIVE: To explore the characteristics of vertebral CT Hounsfield units (HU) in elderly patients with acute vertebral fragility fractures. METHODS: A total of 299 patients aged ≥ 65 years with acute vertebral fragility fractures were retrospectively reviewed, and 77 patients of them were age- and sex-matched with 77 control patients without any fractures. The vertebral HU value of L1(L1-HU) was measured, and T12 and L2 were used as alternatives for L1 in the case of L1 fracture. RESULTS: There were 460 thoracic and lumbar vertebral fractures in the 299 elderly patients, including 349 acute vertebral fragility fractures and 111 chronic fractures. The average L1-HU value was 66.0 ± 30.6 HU and showed significant difference among patients having different numbers of vertebral fractures (one fracture: 73.3 ± 27.0 HU, two fractures: 58.7 ± 32.5 HU, three or more fractures: 40.7 ± 28.8 HU; P < 0.001). As for the 1:1 age- and sex-matched patients, the L1-HU of the 77 patients with fractures was lower than that of the control patients (70.6 ± 23.4 HU vs. 101.5 ± 36.2 HU, P < 0.001). The area under the receiver operating characteristic curve of using L1-HU to differentiate patients with fractures from controls was 0.77(95% CI 0.70-0.85, P < 0.001). The cutoff value had high specificity of 90% or high sensitivity of 90% to identify patients with fractures of 60 HU and 100 HU, respectively. CONCLUSIONS: The elderly patients with acute vertebral fragility fractures have much lower HU values than those without fractures. Moreover, the lower the vertebral HU value is, the more likely the patients have more than one vertebral fracture. These slides can be retrieved under Electronic Supplementary Material.

Differences in standing and sitting spinopelvic sagittal alignment for patients with posterior lumbar fusion: important considerations for the changes of unfused adjacent segments lordosis.

OBJECTIVE: This study aimed to describe the changes in spinopelvic sagittal alignment in the sitting position after posterior lumbar fusion, and to identify the factors influencing unfused adjacent segment lordosis. METHODS: Consecutive patients with lumbar degenerative disease who underwent posterior lumbar interbody fusion between December 2010 and April 2012 were recruited. Lateral full spine radiographs were obtained in the standing, erect sitting, and natural sitting positions. Spinopelvic parameters were measured preoperatively and at the final follow-up. RESULTS: The data of 63 patients were analyzed in this study. The average age was 61.6 ± 11.0 years. When changing from standing to sitting at the final follow-up, all spinopelvic sagittal parameters with the exceptions of pelvic incidence and thoracic kyphosis were significantly altered. The most noticeable changes occurred in the natural sitting position, with the spine slumped toward achieving a C-shaped sagittal profile. Multiple linear regression analysis revealed that when changing to a natural sitting position, age and fusion levels reflected the changes in lumbar lordosis (ΔLL), age and lumbosacral fusion reflected the changes in upper residual lordosis (ΔURL). CONCLUSION: The most noticeable changes in spinopelvic sagittal alignment occurred in the natural sitting position after lumbar fusion. Age, fusion levels, and lumbosacral fusion significantly influenced the differences in LL and URL between the standing and natural sitting position. These characteristics should be fully considered when planning spinal realignment surgery and investigating the etiological factors of junctional complications.

Hounsfield units of the vertebral body and pedicle as predictors of pedicle screw loosening after degenerative lumbar spine surgery.

OBJECTIVE: The authors aimed to compare the efficacy of lumbar vertebral body Hounsfield units (HUs) and pedicle HUs at predicting pedicle screw loosening. METHODS: The authors retrospectively assessed 143 patients with L3-5 instrumentation. The patients were classified into one of two groups based on the status of their L3 screws (a screw loosening group or a control group). The pedicle HUs and vertebral HUs of L3 were measured using preoperative lumbar CT scans, and the pedicle HUs were measured in two ways: by excluding or by including cortical bone. RESULTS: The screw loosening rate was 20.3% (n = 29/143) at the 12-month follow-up. The vertebral body HUs and pedicle HUs in the screw loosening group were lower than those in the control group (vertebral body group: 98.6 HUs vs 121.4 HUs, p < 0.001; pedicle excluding cortical bone: 208.9 HUs vs 290.5 HUs, p = 0.002; pedicle including cortical bone: 249.4 HUs vs 337.5 HUs, p < 0.001). The pedicle HUs tended to have a higher area under the receiver operating characteristic curve value in predicting screw loosening, compared with that of vertebral body HUs, but the difference was not statistically significant (p > 0.05). Among patients with low vertebral body HUs of ≤ 130, the loosening rate was much lower in patients with pedicle HUs of ≤ 340 than in those with pedicle HUs of > 340 (31.0% vs 13.0%, respectively; p < 0.05). CONCLUSIONS: Vertebral body HUs alone are insufficient to accurately evaluate the risk of pedicle screw loosening. Therefore, it is important to collect both the pedicle HU and vertebral body HU measurements for surgical planning.

The use of CT Hounsfield unit values to identify the undiagnosed spinal osteoporosis in patients with lumbar degenerative diseases.

PURPOSES: Our purpose was to use computed tomography (CT) Hounsfield unit (HU) values to identify the undiagnosed spinal osteoporosis in patients with lumbar degenerative diseases. METHODS: A total of 334 patients with lumbar degenerative diseases were retrospectively reviewed and divided into two groups according to the degree of lumbar degenerative changes in preoperative lumbar CT images. Patients who had at least three vertebrae with severe degeneration at L1-L4 were placed in the degenerative group, and others were placed in the control group. HU value of trabecular bone in middle axial CT image of vertebral body, T-score and bone mineral density (BMD) at L1-L4 and hips were measured. CT HU thresholds for osteoporosis were obtained from control group and then applied to identify undiagnosed spinal osteoporosis. RESULTS: There were 182 patients in the degenerative group and 152 patients in the control group. CT HU value had a positive correlation with T-score and BMD of lumbar spine in both groups (P < 0.001), while the correlation coefficients at L1-L4 were higher in the control group (> 0.7) than in the degenerative group (< 0.7). T-score and BMD of lumbar spine were higher in the degenerative group (P < 0.05), while CT HU value, T-score and BMD of hips had no significant difference between two groups. According to the linear regression equations of vertebral T-score and CT HU value in the control group, the thresholds matching T-score of - 2.5 were 110, 100, 85 and 80HU for L1, L2, L3 and L4, respectively. Defining CT osteoporosis as L1 ≤ 110HU or L2 ≤ 100HU or L3 ≤ 85HU or L4 ≤ 80HU was 88.5% (69/78) specific and 60.8% (45/74) sensitive for distinguishing DXA osteoporosis of lumbar spine in the control group. The rate of undiagnosed spinal osteoporosis was higher in the degenerative group than in the control group according to CT HU thresholds (38.7% vs. 11.5%, P < 0.05). CONCLUSIONS: Degenerative changes in the lumbar spine can increase BMD and T-score provided by lumbar DXA, leading to an underestimation of vertebral osteoporosis. Thresholds for osteoporosis based on CT HU values can be used as a complementary method to identify undiagnosed spinal osteoporosis in patients with lumbar degenerative diseases. These slides can be retrieved under Electronic Supplementary Material.