Can self-powered piezoelectric materials be used to treat disc degeneration by means of electrical stimulation?

Intervertebral disc degeneration (IDD) due to multiple causes is one of the major causes of low back pain (LBP). A variety of traditional treatments and biologic therapies are currently used to delay or even reverse IDD; however, these treatments still have some limitations. Finding safer and more effective treatments is urgent for LBP patients. With increasing reports it has been found that the intervertebral disc (IVD) can convert pressure loads from the spine into electrical stimulation in a variety of ways, and that this electrical stimulation is of great importance in modulating cell behavior, the immune microenvironment and promoting tissue repair. However, when intervertebral disc degeneration occurs, the normal structures within the IVD are destroyed. This eventually leads to a weakening or loss of self-powered. Currently various piezoelectric materials with unique crystal structures can mimic the piezoelectric effect of normal tissues. Based on this, tissue-engineered scaffolds prepared using piezoelectric materials have been widely used for regenerative repair of various types of tissues, however, there are no reports of their use for the treatment of IDD. For this reason, we propose to utilize tissue-engineered scaffolds prepared from piezoelectric biomaterials with excellent biocompatibility and self-powered properties to be implanted into degenerated IVD to help restore cell type and number, restore extracellular matrix, and modulate immune responses. It provides a feasible and novel therapeutic approach for the clinical treatment of IDD.

Standardisation is the key to the sustained, rapid and healthy development of stem cell-based therapy.

BACKGROUND: Stem cell-based therapy (SCT) is an important component of regenerative therapy that brings hope to many patients. After decades of development, SCT has made significant progress in the research of various diseases, and the market size has also expanded significantly. The transition of SCT from small-scale, customized experiments to routine clinical practice requires the assistance of standards. Many countries and international organizations around the world have developed corresponding SCT standards, which have effectively promoted the further development of the SCT industry. METHODS: We conducted a comprehensive literature review to introduce the clinical application progress of SCT and focus on the development status of SCT standardization. RESULTS: We first briefly introduced the types and characteristics of stem cells, and summarized the current clinical application and market development of SCT. Subsequently, we focused on the development status of SCT-related standards as of now from three levels: the International Organization for Standardization (ISO), important international organizations, and national organizations. Finally, we provided perspectives and conclusions on the significance and challenges of SCT standardization. CONCLUSIONS: Standardization plays an important role in the sustained, rapid and healthy development of SCT.

Strategies to improve the performance of polyetheretherketone (PEEK) as orthopedic implants: from surface modification to addition of bioactive materials.

Polyetheretherketone (PEEK), as a high-performance polymer, is widely used for bone defect repair due to its homogeneous modulus of elasticity of human bone, good biocompatibility, excellent chemical stability and projectability. However, the highly hydrophobic surface of PEEK is biologically inert, which makes it difficult for cells and proteins to attach, and is accompanied by the development of infections that ultimately lead to failure of PEEK implants. In order to further enhance the potential of PEEK as an orthopedic implant, researchers have explored modification methods such as surface modification by physical and chemical means and the addition of bioactive substances to PEEK-based materials to enhance the mechanical properties, osteogenic activity and antimicrobial properties of PEEK. However, these current modification methods still have obvious shortcomings in terms of cost, maneuverability, stability and cytotoxicity, which still need to be explored by researchers. This paper reviews some of the modification methods that have been used to improve the performance of PEEK over the last three years in anticipation of the need for researchers to design PEEK orthopedic implants that better meet clinical needs.

The application of impantable sensors in the musculoskeletal system: a review.

As the population ages and the incidence of traumatic events rises, there is a growing trend toward the implantation of devices to replace damaged or degenerated tissues in the body. In orthopedic applications, some implants are equipped with sensors to measure internal data and monitor the status of the implant. In recent years, several multi-functional implants have been developed that the clinician can externally control using a smart device. Experts anticipate that these versatile implants could pave the way for the next-generation of technological advancements. This paper provides an introduction to implantable sensors and is structured into three parts. The first section categorizes existing implantable sensors based on their working principles and provides detailed illustrations with examples. The second section introduces the most common materials used in implantable sensors, divided into rigid and flexible materials according to their properties. The third section is the focal point of this article, with implantable orthopedic sensors being classified as joint, spine, or fracture, based on different practical scenarios. The aim of this review is to introduce various implantable orthopedic sensors, compare their different characteristics, and outline the future direction of their development and application.

Incidence and risk factors of surgical site infection following cervical laminoplasty: A retrospective clinical study.

There are many debates regarding the risk factors of surgical site infection (SSI) following posterior cervical surgery in previous studies. And, till now there is no such a study to examine cervical laminoplasty surgery. From January 2011 through October 2021, a total of 405 patients who were treated with unilateral open-door laminoplasty surgeries were enrolled in this study. We divided the patients into the SSI group and the non-SSI group and compared their patient-specific and procedure-specific factors. Univariate and multiple logistic regression analysis were performed to determine the risk factors. Of the 405 patients, 20 patients had SSI. The rate of SSI found to be 4.93%. There were significant differences between groups in the thicker subcutaneous fat thickness (FT) (p < 0.001), the higher ratio of subcutaneous FT to muscle thickness (MT) (p < 0.001), the higher preoperative Japanese Orthopaedic Association (JOA) Scores (p < 0.003), the decreased preoperative serum albumin (p < 0.001), the more postoperative drainage (p < 0.05) and the longer time of draining (p < 0.001). Logistic regression analysis of these differences showed that the higher ratio of subcutaneous FT/MT, the higher preoperative JOA scores, the decreased preoperative serum albumin and the longer time of draining were significantly related to SSI (p < 0.05). The higher ratio of subcutaneous FT/MT, the higher preoperative JOA scores, the decreased preoperative serum albumin and the longer time of draining are identified as the independent risk factors of SSI in cervical laminoplasty. Identification of these risk factors could be useful in reducing the SSI incidence and patients counselling.

Can extracellular vesicles be considered as a potential frontier in the treatment of intervertebral disc disease?

As a global public health problem, low back pain (LBP) caused by intervertebral disc degeneration (IDD) seriously affects patients' quality of life. In addition, the prevalence of IDD tends to be younger, which brings a huge burden to individuals and society economically. Current treatments do not delay or reverse the progression of IDD. The emergence of biologic therapies has brought new hope for the treatment of IDD. Among them, extracellular vesicles (EVs), as nanoscale bioactive substances that mediate cellular communication, have now produced many surprising results in the research of the treatment of IDD. This article reviews the mechanisms and roles of EVs in delaying IDD and describes the prospects and challenges of EVs.

The association between morphological characteristics of paraspinal muscle and spinal disorders.

BACKGROUND: Spinal disorders affect millions of people worldwide, and can cause significant disability and pain. The paraspinal muscles, located on either side of the spinal column, play a crucial role in the movement, support, and stabilization of the spine. Many spinal disorders can affect paraspinal muscles, as evidenced by changes in their morphology, including hypertrophy, atrophy, and degeneration. OBJECTIVES: The objectives of this review were to examine the current literature on the relationship between the paraspinal muscles and spinal disorders, summarize the methods used in previous studies, and identify areas for future research. METHODS: We reviewed studies on the morphological characteristics of the paravertebral muscle and discussed their relationship with spinal disorders, as well as the current limitations and future research directions. RESULTS: The paraspinal muscles play a critical role in spinal disorders and are important targets for the treatment and prevention of spinal disorders. Clinicians should consider the role of the paraspinal muscles in the development and progression of spinal disorders and incorporate assessments of the paraspinal muscle function in clinical practice. CONCLUSION: The findings of this review highlight the need for further research to better understand the relationship between the paraspinal muscles and spinal disorders, and to develop effective interventions to improve spinal health and reduce the burden of spinal disorders.

3D printing metal implants in orthopedic surgery: Methods, applications and future prospects.

Background: Currently, metal implants are widely used in orthopedic surgeries, including fracture fixation, spinal fusion, joint replacement, and bone tumor defect repair. However, conventional implants are difficult to be customized according to the recipient's skeletal anatomy and defect characteristics, leading to difficulties in meeting the individual needs of patients. Additive manufacturing (AM) or three-dimensional (3D) printing technology, an advanced digital fabrication technique capable of producing components with complex and precise structures, offers opportunities for personalization. Methods: We systematically reviewed the literature on 3D printing orthopedic metal implants over the past 10 years. Relevant animal, cellular, and clinical studies were searched in PubMed and Web of Science. In this paper, we introduce the 3D printing method and the characteristics of biometals and summarize the properties of 3D printing metal implants and their clinical applications in orthopedic surgery. On this basis, we discuss potential possibilities for further generalization and improvement. Results: 3D printing technology has facilitated the use of metal implants in different orthopedic procedures. By combining medical images from techniques such as CT and MRI, 3D printing technology allows the precise fabrication of complex metal implants based on the anatomy of the injured tissue. Such patient-specific implants not only reduce excessive mechanical strength and eliminate stress-shielding effects, but also improve biocompatibility and functionality, increase cell and nutrient permeability, and promote angiogenesis and bone growth. In addition, 3D printing technology has the advantages of low cost, fast manufacturing cycles, and high reproducibility, which can shorten patients' surgery and hospitalization time. Many clinical trials have been conducted using customized implants. However, the use of modeling software, the operation of printing equipment, the high demand for metal implant materials, and the lack of guidance from relevant laws and regulations have limited its further application. Conclusions: There are advantages of 3D printing metal implants in orthopedic applications such as personalization, promotion of osseointegration, short production cycle, and high material utilization. With the continuous learning of modeling software by surgeons, the improvement of 3D printing technology, the development of metal materials that better meet clinical needs, and the improvement of laws and regulations, 3D printing metal implants can be applied to more orthopedic surgeries. The translational potential of this paper: Precision, intelligence, and personalization are the future direction of orthopedics. It is reasonable to believe that 3D printing technology will be more deeply integrated with artificial intelligence, 4D printing, and big data to play a greater role in orthopedic metal implants and eventually become an important part of the digital economy. We aim to summarize the latest developments in 3D printing metal implants for engineers and surgeons to design implants that more closely mimic the morphology and function of native bone.

Umbilical cord mesenchymal stem cells for regenerative treatment of intervertebral disc degeneration.

Intervertebral disc degeneration is thought to be a major contributor to low back pain, the etiology of which is complex and not yet fully understood. To compensate for the lack of drug and surgical treatment, mesenchymal stem cells have been proposed for regenerative treatment of intervertebral discs in recent years, and encouraging results have been achieved in related trials. Mesenchymal stem cells can be derived from different parts of the body, among which mesenchymal stem cells isolated from the fetal umbilical cord have excellent performance in terms of difficulty of acquisition, differentiation potential, immunogenicity and ethical risk. This makes it possible for umbilical cord derived mesenchymal stem cells to replace the most widely used bone marrow-derived and adipose tissue derived mesenchymal stem cells as the first choice for regenerating intervertebral discs. However, the survival of umbilical cord mesenchymal stem cells within the intervertebral disc is a major factor affecting their regenerative capacity. In recent years biomaterial scaffolds in tissue engineering have aided the survival of umbilical cord mesenchymal stem cells by mimicking the natural extracellular matrix. This seems to provide a new idea for the application of umbilical cord mesenchymal stem cells. This article reviews the structure of the intervertebral disc, disc degeneration, and the strengths and weaknesses of common treatment methods. We focus on the cell source, cell characteristics, mechanism of action and related experiments to summarize the umbilical cord mesenchymal stem cells and explore the feasibility of tissue engineering technology of umbilical cord mesenchymal stem cells. Hoping to provide new ideas for the treatment of disc degeneration.

Low-temperature deposition manufacturing technology: a novel 3D printing method for bone scaffolds.

The application of three-dimensional printing technology in the medical field has great potential for bone defect repair, especially personalized and biological repair. As a green manufacturing process that does not involve liquefication through heating, low-temperature deposition manufacturing (LDM) is a promising type of rapid prototyping manufacturing and has been widely used to fabricate scaffolds in bone tissue engineering. The scaffolds fabricated by LDM have a multi-scale controllable pore structure and interconnected micropores, which are beneficial for the repair of bone defects. At the same time, different types of cells or bioactive factor can be integrated into three-dimensional structural scaffolds through LDM. Herein, we introduced LDM technology and summarize its applications in bone tissue engineering. We divide the scaffolds into four categories according to the skeleton materials and discuss the performance and limitations of the scaffolds. The ideas presented in this review have prospects in the development and application of LDM scaffolds.

The Digital Twin: A Potential Solution for the Personalized Diagnosis and Treatment of Musculoskeletal System Diseases.

Due to the high prevalence and rates of disability associated with musculoskeletal system diseases, more thorough research into diagnosis, pathogenesis, and treatments is required. One of the key contributors to the emergence of diseases of the musculoskeletal system is thought to be changes in the biomechanics of the human musculoskeletal system. However, there are some defects concerning personal analysis or dynamic responses in current biomechanical research methodologies. Digital twin (DT) was initially an engineering concept that reflected the mirror image of a physical entity. With the application of medical image analysis and artificial intelligence (AI), it entered our lives and showed its potential to be further applied in the medical field. Consequently, we believe that DT can take a step towards personalized healthcare by guiding the design of industrial personalized healthcare systems. In this perspective article, we discuss the limitations of traditional biomechanical methods and the initial exploration of DT in musculoskeletal system diseases. We provide a new opinion that DT could be an effective solution for musculoskeletal system diseases in the future, which will help us analyze the real-time biomechanical properties of the musculoskeletal system and achieve personalized medicine.

[Research progress of platelet-rich plasma in treatment of discogenic low back pain].

Objective: To summarize the research progress of platelet-rich plasma (PRP) for the treatment of discogenic low back pain (DLBP). Methods: The literature on the treatment of DLBP with PRP was extensively reviewed, and the classification, treatment mechanism, in vitro and in vivo experiments and clinical trial progress of PRP were summarized. Results: According to the PRP composition, preparation methods, and physicochemical properties, there are five commonly used PRP classification systems at present. PRP is involved in delaying or reversing the progress of disc degeneration and pain control by promoting the regeneration of nucleus pulposus cells, increasing the synthesis of extracellular matrix, and regulating the internal microenvironment of degenerative intervertebral disc. Although several in vitro and in vivo studies have confirmed that PRP can promote disc regeneration and repair, significantly relieve pain, and even improve the mobility of DLBP patients. But the contrary conclusion has been reached in a few studies, and there are limitations to the application of PRP. Conclusion: Current studies have confirmed the effectiveness and safety of PRP in the treatment of DLBP and intervertebral disc degeneration, as well as the advantages of PRP in terms of ease of extraction and preparation, low immunological rejection, high regenerative and repair capacity, and the ability to compensate for the shortcomings of traditional treatment modalities. However, relevant studies are still needed to further optimize PRP preparation methods, unify systematic classification guidelines, and clarify its long-term effectiveness.

Clinical characteristics and treatment of spinal cord injury in children and adolescents.

Pediatric and adult spinal cord injuries (SCI) are distinct entities. Children and adolescents with SCI must suffer from lifelong disabilities, which is a heavy burden on patients, their families and the society. There are differences in Chinese and foreign literature reports on the incidence, injury mechanism and prognosis of SCI in children and adolescents. In addition to traumatic injuries such as car accidents and falls, the proportion of sports injuries is increasing. The most common sports injury is the backbend during dance practice. Compared with adults, children and adolescents are considered to have a greater potential for neurological improvement. The pathogenesis and treatment of pediatric SCI remains unclear. The mainstream view is that the mechanism of nerve damage in pediatric SCI include flexion, hyperextension, longitudinal distraction and ischemia. We also discuss the advantages and disadvantages of drugs such as methylprednisolone in the treatment of pediatric SCI and the indications and timing of surgery. In addition, the complications of pediatric SCI are also worthy of attention. New imaging techniques such as diffusion tensor imaging and diffusion tensor tractography may be used for diagnosis and assessment of prognosis. This article reviews the epidemiology, pathogenesis, imaging, clinical characteristics, treatment and complications of SCI in children and adolescents. Although current treatment cannot completely restore neurological function, patient quality of life can be enhanced. Continued developments and advances in the research of SCI may eventually provide a cure for children and adolescents with this kind of injury.

The Influence of Intervertebral Disc Microenvironment on the Biological Behavior of Engrafted Mesenchymal Stem Cells.

Intervertebral disc degeneration is the main cause of low back pain. Traditional treatment methods cannot repair degenerated intervertebral disc tissue. The emergence of stem cell therapy makes it possible to regenerate and repair degenerated intervertebral disc tissue. At present, mesenchymal stem cells are the most studied, and different types of mesenchymal stem cells have their own characteristics. However, due to the harsh and complex internal microenvironment of the intervertebral disc, it will affect the biological behaviors of the implanted mesenchymal stem cells, such as viability, proliferation, migration, and chondrogenic differentiation, thereby affecting the therapeutic effect. This review is aimed at summarizing the influence of each intervertebral disc microenvironmental factor on the biological behavior of mesenchymal stem cells, so as to provide new ideas for using tissue engineering technology to assist stem cells to overcome the influence of the microenvironment in the future.

Clinical applications and prospects of 3D printing guide templates in orthopaedics.

Background: With increasing requirements for medical effects, and huge differences among individuals, traditional surgical instruments are difficult to meet the patients' growing medical demands. 3D printing is increasingly mature, which connects to medical services critically as well. The patient specific surgical guide plate provides the condition for precision medicine in orthopaedics. Methods: In this paper, a systematic review of the orthopedic guide template is presented, where the history of 3D-printing-guided technology, the process of guides, and basic clinical applications of orthopedic guide templates are described. Finally, the limitations of the template and possible future directions are discussed. Results: The technology of 3D printing surgical templates is increasingly mature, standard, and intelligent. With the help of guide templates, the surgeon can easily determine the direction and depth of the screw path, and choose the angle and range of osteotomy, increasing the precision, safety, and reliability of the procedure in various types of surgeries. It simplifies the difficult surgical steps and accelerates the growth of young and mid-career physicians. But some problems such as cost, materials, and equipment limit its development. Conclusions: In different fields of orthopedics, the use of guide templates can significantly improve surgical accuracy, shorten the surgical time, and reduce intraoperative bleeding and radiation. With the development of 3D printing, the guide template will be standardized and simplified from design to production and use. 3D printing guides will be further sublimated in the application of orthopedics and better serve the patients. The translational potential of this paper: Precision, intelligence, and individuation are the future development direction of orthopedics. It is more and more popular as the price of printers falls and materials are developed. In addition, the technology of meta-universe, digital twin, and artificial intelligence have made revolutionary effects on template guides. We aim to summarize recent developments and applications of 3D printing guide templates for engineers and surgeons to develop more accurate and efficient templates.