Biomechanical Study of 3 Osteoconductive Materials Applied in Pedicle Augmentation and Revision for Osteoporotic Vertebrae: Allograft Bone Particles, Calcium Phosphate Cement, Demineralized Bone Matrix

Objective This study assessed biomechanical properties of pedicle screws enhanced or revised with 3 materials. We aimed to compare the efficacy of these materials in pedicle augmentation and revision. Methods One hundred twenty human cadaveric vertebrae were utilized for in vitro testing. Vertebrae bone density was evaluated. Allograft bone particles (ABP), calcium phosphate cement (CPC), and demineralized bone matrix (DBM) were used to augment or revise pedicle screw. Post the implantation of pedicle screws, parameters such as insertional torque, pullout strength, cycles to failure and failure load were measured using specialized instruments. Results ABP, CPC, and DBM significantly enhanced biomechanical properties of the screws. CPC augmentation showed superior properties compared to ABP or DBM. ABP-augmented screws had higher cycles to failure and failure loads than DBM-augmented screws, with no difference in pullout strength. CPC-revised screws exhibited similar strength to the original screws, while ABP-revised screws showed comparable cycles to failure and failure loads but lower pullout strength. DBM-revised screws did not match the original screws’ strength. Conclusion ABP, CPC, and DBM effectively improve pedicle screw stability for pedicle augmentation. CPC demonstrated the highest efficacy, followed by ABP, while DBM was less effective. For pedicle revision, CPC is recommended as the primary choice, with ABP as an alternative. However, using DBM for pedicle revision is not recommended

Targeting Oxidative Stress and Inflammation in Intervertebral Disc Degeneration: Therapeutic Perspectives of Phytochemicals

Low back pain is a major cause of disability worldwide that declines the quality of life; it poses a substantial economic burden for the patient and society. Intervertebral disc (IVD) degeneration (IDD) is the main cause of low back pain, and it is also the pathological basis of several spinal degenerative diseases, such as intervertebral disc herniation and spinal stenosis. The current clinical drug treatment of IDD focuses on the symptoms and not their pathogenesis, which results in frequent recurrence and gradual aggravation. Moreover, the side effects associated with the long-term use of these drugs further limit their use. The pathological mechanism of IDD is complex, and oxidative stress and inflammation play an important role in promoting IDD. They induce the destruction of the extracellular matrix in IVD and reduce the number of living cells and functional cells, thereby destroying the function of IVD and promoting the occurrence and development of IDD. Phytochemicals from fruits, vegetables, grains, and other herbs play a protective role in the treatment of IDD as they have anti-inflammatory and antioxidant properties. This article reviews the protective effects of phytochemicals on IDD and their regulatory effects on different molecular pathways related to the pathogenesis of IDD. Moreover, the therapeutic limitations and future prospects of IDD treatment have also been reviewed. Phytochemicals are promising candidates for further development and research on IDD treatment.</jats:p

Deposition Flux, Stocks of C, N, P, S, and Their Ecological Stoichiometry in Coastal Wetlands With Three Plant Covers

The depositional flux of coastal wetlands and the deposition rate of biogenic elements greatly affect the carbon sink storage. Ecological stoichiometry is an important ecological indicator, which can simply and intuitively indicate the biogeochemical cycle process of the region. This study investigated the soil deposition flux, stocks, and ecological stoichiometric ratios of C, N, P, and S under different water and salt conditions based on 137Cs dating technology in the Yellow River Delta (YRD) of China. The results showed that the deposition fluxes were 0.38 cm/year for PV wetlands, 1.08 cm/yr for PA wetlands, and 1.06 cm/yr for SS wetlands. Similarly, PA wetlands showed higher deposition fluxes of C, N, and S compared with SS and PV wetlands. PA wetlands had higher stocks of C (5.86 kg/m2), N (0.36 kg/m2) and S (0.36 kg/m2) in the top 1-m soil layer compared with PV and SS wetlands. However, the highest deposition rate of P (9.82 g/yr/m2) was observed in SS wetlands among the three wetlands. Three accumulative hotspots of C, N, and S in soil profiles of PA and SS wetlands were observed at soil depths of 0–10, 40–60, and 90–100 cm, whereas one accumulative hotspot of P was at the soil depth of 10–12 cm in SS wetlands and 80–82 cm in PA wetlands. PV wetlands showed higher accumulations of C, P, and S in the top 10 cm soil layer and N at the soil depth of 90–100 cm. The higher top concentration factors in these three wetlands indicated that the dominant input of plant residues was the main reason. The ratios of C/N and C/N/P of each sampling site were higher in the surface soils and decreased with depth. The ratios of C/P and N/P were larger in the surface layer (0–20 cm), the middle layer (40–60 cm), and the deep layer (90–100 cm). The ratios of N/P and C/N/P were relatively lower, indicating that these studied wetlands were N-limited ecosystems. The results implied that the coastal wetlands in the YRD have huge storage potential of biogenic elements as blue carbon ecosystems.</jats:p