Sagittal balance parameters measurement on cervical spine MR images based on superpixel segmentation.

Introduction: Magnetic Resonance Imaging (MRI) is essential in diagnosing cervical spondylosis, providing detailed visualization of osseous and soft tissue structures in the cervical spine. However, manual measurements hinder the assessment of cervical spine sagittal balance, leading to time-consuming and error-prone processes. This study presents the Pyramid DBSCAN Simple Linear Iterative Cluster (PDB-SLIC), an automated segmentation algorithm for vertebral bodies in T2-weighted MR images, aiming to streamline sagittal balance assessment for spinal surgeons. Method: PDB-SLIC combines the SLIC superpixel segmentation algorithm with DBSCAN clustering and underwent rigorous testing using an extensive dataset of T2-weighted mid-sagittal MR images from 4,258 patients across ten hospitals in China. The efficacy of PDB-SLIC was compared against other algorithms and networks in terms of superpixel segmentation quality and vertebral body segmentation accuracy. Validation included a comparative analysis of manual and automated measurements of cervical sagittal parameters and scrutiny of PDB-SLIC's measurement stability across diverse hospital settings and MR scanning machines. Result: PDB-SLIC outperforms other algorithms in vertebral body segmentation quality, with high accuracy, recall, and Jaccard index. Minimal error deviation was observed compared to manual measurements, with correlation coefficients exceeding 95%. PDB-SLIC demonstrated commendable performance in processing cervical spine T2-weighted MR images from various hospital settings, MRI machines, and patient demographics. Discussion: The PDB-SLIC algorithm emerges as an accurate, objective, and efficient tool for evaluating cervical spine sagittal balance, providing valuable assistance to spinal surgeons in preoperative assessment, surgical strategy formulation, and prognostic inference. Additionally, it facilitates comprehensive measurement of sagittal balance parameters across diverse patient cohorts, contributing to the establishment of normative standards for cervical spine MR imaging.

[Robot-assisted PVP for the treatment of osteoporotic fractures of the upper thoracic vertebra].

OBJECTIVE: To investigate the clinical effect of "Tianji" orthopedic robot-assisted percutaneous vertebro plasty(PVP) surgery in the treatment of upper thoracic osteoporotic fracture. METHODS: A retrospective analysis was performed on 32 patients with upper thoracic osteoporotic fracture who underwent PVP surgery in Shenzhen Hospital of Traditional Chinese Medicine from August 2016 to June 2022. There were 8 males and 24 females, ranging in age from 58 to 90 years old, with a mean of (67.75±12.27) years old. Fifteen patients were treated with robot-assisted PVP surgery (robot group), including 3 males and 12 females, with an average age of (68.5±10.3) years. Fracture location:1 case of T2 fracture, 1 case of T3 fracture, 3 cases of T4 fracture, 3 cases of T5 fracture, and 7 cases of T6 fracture. The follow-up period ranged from 1.0 to 3.0 months, with a mean of (1.6±0.7) months. Seventeen patients underwent routine PVP surgery (conventional group), including 5 males and 12 females, with an average age of (66.8±11.6) years old. Fracture location:1 case of T1 fracture, 5 cases of T4 fracture, 2 cases of T5 fracture and 9 cases of T6 fracture. The follow-up period ranged from 0.5 to 4.0 months, with a mean of (1.5±0.6) months. Preoperative and postoperative visual analogue scale(VAS) and Oswestry disability index(ODI) scores were compared between the two groups, and the number of punctures, perspective times, operation time, intraoperative blood loss, bone cement distribution, bone cement leakage, and intraoperative radiation dose were compared between the two groups. RESULTS: Number of punctures times, perspective times, operation time, intraoperative blood loss, bone cement distribution, bone cement leakage and intraoperative radiation dose in the robot group were all significantly better than those in the conventional group(P<0.05). VAS of 2.03±0.05 and ODI of (22.16±4.03) % in the robot group were significantly better than those of the robot group before surgery, which were (8.67±0.25) score and (79.40±7.72)%(t=100.869, P<0.001;t=25.456, P<0.001). VAS of 2.17±0.13 and ODI of (23.88±6.15)% in the conventional group were significantly better than those before surgery, which were (8.73±0.18) score and (80.01±7.59)%(t=121.816, P<0.001;t=23.691, P<0.001). There was no significant difference in VAS and ODI between the two groups after operation (t=-3.917, P=0.476;t=-0.922, P=0.364). CONCLUSION: Robot-assisted PVP in the treatment of upper thoracic osteoporotic fractures can further improve surgical safety, reduce bone cement leakage, and achieve satisfactory clinical efficacy.

Aberrant spinal mechanical loading stress triggers intervertebral disc degeneration by inducing pyroptosis and nerve ingrowth.

Aberrant mechanical factor is one of the etiologies of the intervertebral disc (IVD) degeneration (IVDD). However, the exact molecular mechanism of spinal mechanical loading stress-induced IVDD has yet to be elucidated due to a lack of an ideal and stable IVDD animal model. The present study aimed to establish a stable IVDD mouse model and evaluated the effect of aberrant spinal mechanical loading on the pathogenesis of IVDD. Eight-week-old male mice were treated with lumbar spine instability (LSI) surgery to induce IVDD. The progression of IVDD was evaluated by µCT and Safranin O/Fast green staining analysis. The metabolism of extracellular matrix, ingrowth of sensory nerves, pyroptosis in IVDs tissues were determined by immunohistological or real-time PCR analysis. The apoptosis of IVD cells was tested by TUNEL assay. IVDD modeling was successfully produced by LSI surgery, with substantial reductions in IVD height, BS/TV, Tb.N. and lower IVD score. LSI administration led to the histologic change of disc degeneration, disruption of the matrix metabolism, promotion of apoptosis of IVD cells and invasion of sensory nerves into annulus fibrosus, as well as induction of pyroptosis. Moreover, LSI surgery activated Wnt signaling in IVD tissues. Mechanical instability caused by LSI surgery accelerates the disc matrix degradation, nerve invasion, pyroptosis, and eventually lead to IVDD, which provided an alternative mouse IVDD model.

Suppression of Oxygen Vacancy Defects in sALD-ZnO Films Annealed in Different Conditions.

Zinc oxide (ZnO) has drawn much attention due to its excellent optical and electrical properties. In this study, ZnO film was prepared by a high-deposition-rate spatial atomic layer deposition (ALD) and subjected to a post-annealing process to suppress the intrinsic defects and improve the crystallinity and film properties. The results show that the film thickness increases with annealing temperature owing to the increment of oxide layer caused by the suppression of oxygen vacancy defects as indicated by the X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) spectra. The film transmittance is seldom influenced by annealing. The refractive index increases with annealing temperature at 300-700 °C, possibly due to higher density and crystallinity of the film. The band gap decreases after annealing, which should be ascribed to the decrease in carrier concentration according to Burstein-Moss model. The carrier concentration decreases with increasing annealing temperature at 300-700 °C since the oxygen vacancy defects are suppressed, then it increases at 800 °C possibly due to the out-diffusion of oxygen atoms from the film. Meanwhile, the carrier mobility increases with temperature due to higher crystallinity and larger crystallite size. The film resistivity increases at 300-700 °C then decreases at 800 °C, which should be ascribed primarily to the variation of carrier concentration.

Zinc Oxide Films with High Transparency and Crystallinity Prepared by a Low Temperature Spatial Atomic Layer Deposition Process.

Zinc oxide (ZnO) attracts much attention owing to its remarkable electrical and optical properties for applications in optoelectronics. In this study, ZnO thin films were prepared by spatial atomic layer deposition with diethylzinc and water as precursors. The substrate temperature was varied from 55 to 135 °C to investigate the effects on the optical, electrical, and structural properties of the films. All ZnO samples exhibit an average transmittance in visible and near-infrared light range exceeding 80% and a resistivity in the range of (3.2-9.0) × 10-3 Ω·cm when deposited on a borosilicate glass with a refractive index of ≈1.52. The transmittance, band gap, refractive index, and extinction coefficient are rarely affected, while the resistivity only slightly decreases with increasing temperature. This technique provides a wide process window for depositing ZnO thin films. The results revealed that the films deposited at a substrate of 55 °C were highly crystalline with a preferential (1 0 0) orientation. In addition, the grains grow larger as the substrate temperature increases. The electrical properties and reliability of ZnO/PET samples are also studied in this paper.

[Finite element analysis of maxillary anterior teeth retraction of posterior teeth with different alveolar bone absorption heights under orthodontic force].

OBJECTIVE: This study applied the direct orthodontic force system to explore the applicability of the finite element method in the simulation of alveolar bone absorption and analyze periodontal stress distribution and the overall displacement trend. METHODS: The horizontal balanced alveolar bones of model 2, 3 and 4 were reduced by 2, 4, and 6 mm by deleting elements in reference to the established height of the normal alveolar bone model 1. Then, stress distribution on the posterior set of teeth and initial total tooth displacement under the simulated load of 1.47 N of orthodontic force were investigated. RESULTS: The total displacement of posterior teeth increased and parodontium Von Mises stress gradually increased as the alveolar bone height decreased. The total displacement trend and parodontium stress drastically increased when alveolar bone absorp-tion reached the height of 4 mm. CONCLUSIONS: When treating patients with alveolar bone loss, stress should be avoided or drasti-cally reduced to prevent irreversible damage to periodontal tissue and to improve the quality of medical treatment.

[Internal fixation combined with bone grafting through the injured pedicle for the treatment of thoracolumbar burst fractures via a paraspinal intermuscular approach under MAST Quadrant retractor].

OBJECTIVE: To study clinical effects of short-segment fixation and injured vertebra bone grafting through injured pedicle for the treatment of thoracolumbar burst fractures under MAST Quadrant retractor via a paraspinal muscle approach. METHODS: The data of 42 patients with thoracolumbar burst fractures treated from June 2009 to September 2012 were reviewed. There were 19 males and 23 females, with an average age of (55.2±11.9) years old. The mean injury time was (5.8±4.3) days. Fracture segments included T10 in 3 cases, T11 in 6 cases, T12 in 13 cases, L1 in 9 cases, L2 in 7 cases, and L3 in 4 cases. According to Denis classification, 9 patients were type A, 21 patients were type B, 5 patiens were type C, 5 patients were type D, and 2 patients were type E. All the patients were treated with short-segment pedicle screw-rod system fixation under MAST Quadrant via the paraspinal muscle approach. The operative time, blood loss, complications and the height of vertebra, kyphosis Cobb angle, VAS scores, JOA scores were measured before and after treatment. RESULTS: After treatment, the vertebral height and kyphosis Cobb angle were restored. Compared with preoperative results, postoperative vertebral height and kyphosis Cobb angle, VAS scores and JOA scores were all improved. But there was no statistically significance in vertebral height, kyphosis Cobb angle between postoperative at 1 week and 1 year. CONCLUSION: Internal fixation combined with injured vertebra bone grafting through the injured pedicle for the treatment of thoracolumbar burst fractures via the paraspinal intermuscular approach under MAST Quadrant is a safe, minimally invasive, effective and satisfactory method.

[Regulation of single herb pilose antler on the expression of Smad2 and Smad3 in the cartilage of OA rats: an experimental research].

OBJECTIVE: To observe the effect of single herb pilose antler (PA) on the expression of Smad2 and Smad3 in the cartilage of osteoarthritis (OA) rats. METHODS: One hundred 3-month old female healthy SD rats, (200 +/- 20) g, were recruited and routinely fed for 1 week. They were randomly divided into 5 groups, i.e., the low dose PA group, the high dose PA group, the normal saline control group, the model group, and the normal control group, 20 in each group. The model was prepared using classic Hulth method except the normal control group. After 6-week modeling, the model was confirmed successful by pathologic observation. PA at 0.021 g/100 g and 0.084 g/1 00 g was given by gastrogavage to rats in the low dose PA group and the high dose PA group respectively. Normal saline was administered to those in the normal saline control group. No treatment was given to rats in the normal control group and the model group. Bilateral knee cartilages were harvested at week 2,4, and 6. mRNA and protein expressions of Smad2 and Smad3 were detected by immunohistochemical assay, fluorescent quantitative PCR, and Western blot. RESULTS: OA model was successfully prepared by pathological observation. Results of immunohistochemical assay showed that Smad2 and Smad3 expressed extensively in the cartilage, and located inside the chondrocyte membrane. Compared with the model group, mRNA expression of Smad2 and Smad3 obviously increased in the low dose PA group and the high dose PA group at week 2, 4, and 6, showing statistical difference (P < 0.05). Compared with the same group at week 4 after gastrogavage, mRNA expression of Smad2 and Smad3 obviously decreased in the low dose PA group and the high dose PA group at week 6, showing statistical difference (P < 0.05). Compared with the model group, protein expression of Smad2 and Smad3 obviously increased in the chondrocytes of the low dose PA group and the high dose PA group at week 2 and 4, showing statistical difference (P < 0.01). Compared with the same group at week 2 after gastrogavage, protein expression of Smad2 and Smad3 obviously increased in the low dose PA group and the high dose PA group at week 4, showing statistical difference (P < 0.01). Compared with the same group at week 4 after gastrogavage, protein expression of Smad2 and Smad3 obviously decreased in the low dose PA group and the high dose PA group at week 6, showing statistical difference (P < 0.01). CONCLUSIONS: (1) The pilose antler could repair cartilages by regulating mRNA and protein expressions of Smad2 and Smad3. (2) Up-regulating mRNA and protein expressions of Smad2 and Smad3 might be one of important mechanisms for the pathogenesis of OA.

GISSD: Group I Intron Sequence and Structure Database.

Group I Intron Sequence and Structure Database (GISSD) is a specialized and comprehensive database for group I introns, focusing on the integration of useful group I intron information from available databases and providing de novo data that is essential for understanding these introns at a systematic level. This database presents 1789 complete intron records, including the nucleotide sequence of each annotated intron plus 15 nt of the upstream and downstream exons, and the pseudoknots-containing secondary structures predicted by integrating comparative sequence analyses and minimal free energy algorithms. These introns represent all 14 subgroups, with their structure-based alignments being separately provided. Both structure predictions and alignments were done manually and iteratively adjusted, which yielded a reliable consensus structure for each subgroup. These consensus structures allowed us to judge the confidence of 20 085 group I introns previously found by the INFERNAL program and to classify them into subgroups automatically. The database provides intron-associated taxonomy information from GenBank, allowing one to view the detailed distribution of all group I introns. CDSs residing in introns and 3D structure information are also integrated if available. About 17 000 group I introns have been validated in this database; approximately 95% of them belong to the IC3 subgroup and reside in the chloroplast tRNA(Leu) gene. The GISSD database can be accessed at http://www.rna.whu.edu.cn/gissd/