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Percutaneous endoscopic lumbar discectomy (PELD) is an effective surgical option for lumbar disc herniation (LDH) but is associated with lumbar intervertebral disc rehydration in some patients. However, the incidence of rehydration is not clearly, and only a few studies have discussed this in detail. The study aimed at investigating the factors influencing intervertebral disc rehydration in a series of patients with LDH who underwent PELD. Ninety-six patients with single-level LDH who underwent PELD at Shenzhen Traditional Chinese Medicine Hospital from October 2013 to May 2021 were studied. The relevant data of the patients were recorded such as age, course of disease, sex, body mass index (BMI), diabetes mellitus, hypertension, smoking status, and postoperative exercise; imaging factors such as Modic changes of adjacent vertebrae at surgical level, Pfirrmann grade, degree of disc herniation (Komori classification), and spinal canal morphology; peripheral blood factors such as blood routine parameters, C-reactive protein level, erythrocyte sedimentation rate (ESR), and Th1/Th2 subgroup analysis; and operation-related factors such as surgical approach, length of operation, and amount of blood loss. Univariate analysis and binary logistic regression analysis were conducted to determine the influence of the above parameters on disc rehydration. Our results showed that Young patients with intervertebral disc herniation with a short course of disease, no smoking history, not overweight, no history of diabetes, with intervertebral disc herniation type of Komori Type C, Pfirrmann grade IV, and no adjacent vertebral Modic changes, coupled with high levels of mononuclear cells and TNF-α in peripheral blood, may be more prone to rehydration after PELD.

Background Intervertebral disk degeneration (IVDD) is closely associated with inflammatory environments. Curcumol has been shown to alleviate inflammation in various disease models, but its effects on IVDD remain unclear. In this study, we sought to determine the mechanism of curcumol in tumor necrosis factor (TNF)-α−induced nucleus pulposus cells and a mouse IVDD model. Methods Nucleus pulposus cells were pretreated with curcumol and then exposed to TNF-α. Cell viability was analyzed using CCK-8, and the messenger ribonucleic acid and protein levels of inflammatory cytokines and PI3K/Akt/NF-κB-related signaling molecules were detected using real-time polymerase chain reaction, enzyme-linked immunosorbent assay, and western blotting. The mouse IVDD model was established by puncturing the C6/7 level of the caudal spine, and then it was treated with curcumol after surgery. Alcian blue/orange G staining was performed to evaluate the severity of intervertebral disk damage, and immunohistochemistry was performed to detect the expression of TNF-α. Toxicologic effects of curcumol were measured by performing hematoxylin-eosin staining and enzyme-linked immunosorbent assay. Results Curcumol reduced IL-1β, IL-6, and TNF-α production in NPCs, and the phosphorylation of proteins in the PI3K/Akt/NF-κB signaling pathway was also decreased. The PI3K/Akt/NF-κB-related signaling molecules decreased when TNF-α-induced NPCs were treated with a PI3K inhibitor; however, curcumol did not reverse these effects. In vivo, curcumol ameliorated the progression of IVDD at the early stage and did not exert toxicologic effects. Conclusions These results suggest a potential therapeutic use of curcumol to alleviate inflammation via the PI3K/Akt/NF-κB signaling pathway and delay the progression of IVDD.

NiTi alloy has a wide range of applications as a biomaterial due to its high ductility, low corrosion rate, and favorable biocompatibility. Although Young’s modulus of NiTi is relatively low, it still needs to be reduced; one of the promising ways is by introducing porous structure. Traditional manufacturing processes, such as casting, can hardly produce complex porous structures. Additive manufacturing (AM) is one of the most advanced manufacturing technologies that can solve impurity issues, and selective laser melting (SLM) is one of the well-known methods. This paper reviews the developments of AMNiTi with a particular focus on SLM-NiTi utilization in biomedical applications. Correspondingly, this paper aims to describe the three key factors, including powder preparation, processing parameters, and gas atmosphere during the overall process of porous NiTi. The porous structure design is of vital importance, so the unit cell and pore parameters are discussed. The mechanical properties of SLM-NiTi, such as hardness, compressive strength, tensile strength, fatigue behavior, and damping properties and their relationship with design parameters are summarized. In the end, it points out the current challenges. Considering the increasing application of NiTi implants, this review paper may open new frontiers for advanced and modern designs.

Additive manufacturing (AM) is among the most attractive methods to produce implants, the processes are very swift and it can be precisely controlled to meet patient’s requirement since they can be produced in exact shape, dimension, and even texture of different living tissues. Until now, lots of methods have emerged and used in this field with diverse characteristics. This review aims to comprehensively discuss 3D printing (3DP) technologies to manufacture metallic implants, especially on techniques and procedures. Various technologies based on their main properties are categorized, the effecting parameters are introduced, andthe history of AM technology is briefly analyzed. Subsequently, the utilization of these AM-manufactured components in medicine along with their effectual variables is discussed, and special attention is paid on to the production of porous scaffolds, taking pore size, density, etc., into consideration. Finally, 3DP of the popular metallic systems in medical applications such as titanium, Ti6Al4V, cobalt-chromium alloys, and shape memory alloys are studied. In general, AM manufactured implants need to comply with important requirements such as biocompatibility, suitable mechanical properties (strength and elastic modulus), surface conditions, custom-built designs, fast production, etc. This review aims to introduce the AM technologies in implant applications and find new ways to design more sophisticated methods and compatible implants that mimic the desired tissue functions.

Friction stir processing (FSP) was successfully employed to produce gradient multi-phase structured Ti–6Al–4V/Ag nanocomposite surface layer. Microstructural evolution of amorphous/nanocrystalline/nano-twin in the surface layer was characterized by TEM in detail. The formation of amorphous phase in the upper surface of stir zone (SZ) was attributed to mechanically driven amorphization caused by dislocation gliding plastic deformation and elements mixing process. The dislocation activities played a dominant role in causing the distortion of lattices and nanocrystallization. The plastic deformation via FSP was responsible for considerable dislocations pile-up and tangle in the potential deformation bands.

Although Ti-6Al-4V has been widely used in biomaterial field. Compared with other classes of materials, it still encounters some problems such as low surface hardness and relative low biocompatibility. To solve these problems friction stir processing (FSP) was applied to fabricate a nanosized composite layer of TiO2 and Ti-6Al-4V. Uniform distribution of TiO2 particles with some clusters on the surface of alloy can be observed. Due to severe plastic deformation and stirring heat, nanocrystallines and amorphous TiO2 can be observed in stir zone. FSPed samples show significant improvement in surface microhardness and biocompatibility due to its modified structure compared with original sample. In addition, through corrosion behaviors of the samples in simulated body fluid, it is found that FSP can enhance whilst TiO2 reduces the possibility and corrosion rate of material in environment of human body.

Implant-associated infections (IAIs) are among the most intractable and costly complications in implant surgery. They can lead to surgery failure, a high economic burden, and a decrease in patient quality of life. This manuscript is devoted to introducing current antimicrobial strategies for additively manufactured (AM) titanium (Ti) implants and fostering a better understanding in order to pave the way for potential modern high-throughput technologies. Most bactericidal strategies rely on implant structure design and surface modification. By means of rational structural design, the performance of AM Ti implants can be improved by maintaining a favorable balance between the mechanical, osteogenic, and antibacterial properties. This subject becomes even more important when working with complex geometries; therefore, it is necessary to select appropriate surface modification techniques, including both topological and chemical modification. Antibacterial active metal and antibiotic coatings are among the most commonly used chemical modifications in AM Ti implants. These surface modifications can successfully inhibit bacterial adhesion and biofilm formation, and bacterial apoptosis, leading to improved antibacterial properties. As a result of certain issues such as drug resistance and cytotoxicity, the development of novel and alternative antimicrobial strategies is urgently required. In this regard, the present review paper provides insights into the enhancement of bactericidal properties in AM Ti implants.

Reconstruction of bone defects is still a challenge. In this study, we developed and systematically evaluated a novel injectable strontium-containing hydroxyapatite (Sr-HA) bone cement in which Sr-HA powder included 5% Sr and was mixed with a setting liquid that included 5% potassium citrate. This Sr-HA cement was mainly composed of HA and α-tricalcium phosphate (TCP) and exhibited favorable injectability (100%), setting times (the initial setting time was 240 s and the final setting time was 420 s), compressive strength (73.4 MPa), maximal load and maximum bending stress, and excellent radiopacity. In addition, the Sr-HA cement also had excellent biocompatibility that exhibited low cytotoxicity for cell proliferation and no obvious disturbing effect on the osteogenic differentiation of periodontal ligament stem cells (DLSCs) and dental pulp stem cells (DPSCs). However, the Sr-HA cement could slightly promote the osteogenic differentiation of MC3T3 cells, which also implied that it would promote osseointegration between the cement and surrounding bone but would not obviously disturb the biological behavior of DLSCs and DPSCs. An in vivo study further confirmed that Sr-HA cement exhibited favorable osseointegration with the maxilla and tibia. All these findings implied that the novel Sr-HA cement was a suitable bone substitution for bone defects.

Numerous antibacterial biomaterials have been developed, but a majority of them suffer from poor biocompatibility. With the purpose of reducing biomaterial-related infection and cytotoxicity, friction stir processing (FSP) was employed to embed silver nanoparticles (Ag NPs) in a Ti-6Al-4V (TC4) substrate. Characterization using scanning electron microscopy, transmission electron microscopy, and three-dimensional atom probe tomography illustrates that NPs are distributed more homogeneously on the surface of TC4 as the groove depth increases, and silver-rich NPs with a size from 10 to 20 nm exist as metallic silver diffused into the substrate, where the silver content is 4.3-5.6%. Electrochemical impedance spectroscopy shows that both FSP and the addition of silver have positive effects on corrosion resistance. The modified samples effectively inhibit both Staphylococcus aureus and Escherichia coli strains and slightly reduce their adhesion while not displaying any cytotoxicity to bone mesenchymal stem cells in vitro. The antibacterial effect is independent of Ag-ion release and is likely due to the number of embedded silver NPs on the surface, which directly contact and subsequently destroy the cell membrane. Our study shows that the TC4/Ag metal matrix nanocomposite is a potential infection-related biomaterial and that embedding Ag NPs tightly on a biomaterial surface is an effective strategy for striking a balance between the antibacterial effect and biocompatibility, providing an innovative approach for accurately controlling the cytotoxicity of infection-related biomaterials.

Ti–xNb–3Zr–2Ta alloys (x = 33, 31, 29, 27, 25) (wt.%) were fabricated by vacuum non-consumable arc melting and hot forging. The hot-forging specimens were solid solution treated at 1053 K for 1.8 ks followed by water quenching (WQ) and air cooling (AC) respectively. The microstructure of hot-forging specimens with different deformation rate and solid solution treated at different temperatures was investigated. The result showed that a large amount of α" martensite appeared in the WQ group while only a little amount of α" phase could be found in the AC group. Moreover, for the WQ group, less niobium resulted in more diffraction peaks of α" phase in XRD profiles. This result suggested that the stability of β phase decreased with the decrease of Nb content. The microhardness of Ti–xNb–3Zr–2Ta (wt.%) alloys was improved significantly with the decreasing Nb content in both WQ group and AC group. Increasing deformation ratio could effectively refine β grains for Ti–25N–3Zr–2Ta (wt.%). Both acicular martensite and lath martensite were found in the transmission electron microscope observation of Ti–25Nb–3Zr–2Ta (wt.%) alloy. Martensitic internal twins were identified as well.

Polyoxymethylene/carbon fiber(POM/CF)composites containing nano-SiO2 were prepared, and their mechanical properties were investigated. At a content of 1-5 vol.%, the nano-SiO2 exerted an obvious reinforcing effect on POM, leading to an increase in the elastic modulus and stiffness of the composites.

The influence of oxygen content on microstructure and mechanical properties of Ti–22.5Nb–0.7Ta–2Zr (at.%) alloy was investigated in this work. According to experiments, the grains were refined apparently when the oxygen content was between 1.5% and 2.0%. The ultimate tensile strength (UTS) increased and elongation decreased with increasing oxygen content. But at the content of 1.0%, the elongation was nearly the same to that of the original alloy (about 16%). The elastic modulus remained comparatively low (