The Effectiveness of Artificial Intelligence-based Pedicle Screw Trajectory Planning in Patients With Different Levels of Bone Mineral Density.

Study Design: Retrospective cohort study.

Objective: To evaluate the effectiveness of pedicle screw trajectory planning based on artificial intelligence (AI) software in patients with different levels of bone mineral density (BMD).

Summary Of Background Data: AI-based pedicle screw trajectory planning has potential to improve pullout force (POF) of screws.

3D Bioprinting of Artificial Skin Substitute with Improved Mechanical Property and Regulated Cell Behavior through Integrating Patterned Nanofibrous Films.

Three-dimensional (3D) bioprinting has advantages for constructing artificial skin tissues in replicating the structures and functions of native skin. Although many studies have presented improved effect of printing skin substitutes in wound healing, using hydrogel inks to fabricate 3D bioprinting architectures with complicated structures, mimicking mechanical properties, and appropriate cellular environments is still challenging. Inspired by collagen nanofibers withstanding stress and regulating cell behavior, a patterned nanofibrous film was introduced to the printed hydrogel scaffold to fabricate a composite artificial skin substitute (CASS).

Targeting adipocyte ESRRA promotes osteogenesis and vascular formation in adipocyte-rich bone marrow.

Excessive bone marrow adipocytes (BMAds) accumulation often occurs under diverse pathophysiological conditions associated with bone deterioration. Estrogen-related receptor α (ESRRA) is a key regulator responding to metabolic stress. Here, we show that adipocyte-specific ESRRA deficiency preserves osteogenesis and vascular formation in adipocyte-rich bone marrow upon estrogen deficiency or obesity.

Bidirectional control of parathyroid hormone and bone mass by subfornical organ.

Parathyroid hormone (PTH) is one of the most important hormones for bone turnover and calcium homeostasis. It is unclear how the central nervous system regulates PTH. The subfornical organ (SFO) lies above the third ventricle and modulates body fluid homeostasis.

Distribution of bone voids in the thoracolumbar spine in Chinese adults with and without osteoporosis: A cross-sectional multi-center study based on 464 vertebrae.

Bone void is a novel intuitive morphological indicator to assess bone quality but its use in vertebrae has not been described. This cross-sectional and multi-center study aimed to investigate the distribution of bone voids in the thoracolumbar spine in Chinese adults based on quantitative computed tomography (QCT). A bone void was defined as a trabecular net region with extremely low bone mineral density (BMD) (<40 mg/cm), detected by an algorithm based on phantom-less technology.

A Unified Therapeutic-Prophylactic Tissue-Engineering Scaffold Demonstrated to Prevent Tumor Recurrence and Overcoming Infection toward Bone Remodeling.

Osteosarcoma occurs in children and adolescents frequently and leads to a high fatality rate. Although surgical resection is the most common methods in clinic, patients always suffer from tumor metastasis and recurrence and it is difficult for them to self-repair large bone defects. Furthermore, the postoperative infection from bacteria triggers an inflammatory response and hinders the bone-repair process.

One Novel Phantom-Less Quantitative Computed Tomography System for Auto-Diagnosis of Osteoporosis Utilizes Low-Dose Chest Computed Tomography Obtained for COVID-19 Screening.

The diagnosis of osteoporosis is still one of the most critical topics for orthopedic surgeons worldwide. One research direction is to use existing clinical imaging data for accurate measurements of bone mineral density (BMD) without additional radiation. A novel phantom-less quantitative computed tomography (PL-QCT) system was developed to measure BMD and diagnose osteoporosis, as our previous study reported.

Infiltration from Suspension Systems Enables Effective Modulation of 3D Scaffold Properties in Suspension Bioprinting.

Bioprinting is a biofabrication technology which allows efficient and large-scale manufacture of 3D cell culture systems. However, the available biomaterials for bioinks used in bioprinting are limited by their printability and biological functionality. Fabricated constructs are often homogeneous and have limited complexity in terms of current 3D cell culture systems comprising multiple cell types.

Osteoarthritis Pain.

Joint pain is the hallmark symptom of osteoarthritis (OA) and the main reason for patients to seek medical assistance. OA pain greatly contributes to functional limitations of joints and reduced quality of life. Although several pain-relieving medications are available for OA treatment, the current intervention strategy for OA pain cannot provide satisfactory pain relief, and the chronic use of the drugs for pain management is often associated with significant side effects and toxicities.

Cultural Validation of the Chinese Central Sensitization Inventory in Patients with Chronic Pain and its Predictive Ability of Comorbid Central Sensitivity Syndromes.

Background: Central sensitization (CS) is frequently reported in chronic pain, and the central sensitization inventory (CSI) is popularly used to assess CS. However, a validated Chinese CSI is lacking and its predictive ability for the comorbidity of central sensitivity syndromes (CSSs) remains unclear. Hence, this study aimed to generate the Chinese CSI (CSI-C) with cultural adaptation and examine its psychometric properties.

3D-bioprinted BMSC-laden biomimetic multiphasic scaffolds for efficient repair of osteochondral defects in an osteoarthritic rat model.

Osteochondral defect repair in osteoarthritis (OA) remains an unsolved clinical problem due to the lack of enough seed cells in the defect and chronic inflammation in the joint. To address this clinical need, we designed a bone marrow-derived mesenchymal stem cell (BMSC)-laden 3D-bioprinted multilayer scaffold with methacrylated hyaluronic acid (MeHA)/polycaprolactone incorporating kartogenin and β-TCP for osteochondral defect repair within each region. BMSC-laden MeHA was designed to actively introduce BMSCs in situ, and diclofenac sodium (DC)-incorporated matrix metalloproteinase-sensitive peptide-modified MeHA was induced on the BMSC-laden scaffold as an anti-inflammatory strategy.

Types of vertebral fractures could influence the selection of clinical bone mineral measures to predict biomechanical properties.

Areal and volumetric BMD (aBMD and vBMD) measured by DXA and quantitative CT (QCT), respectively, are usually employed to predict vertebral fracture risks. In this study, we induced compression and wedge vertebral fractures to test if the types of fracture could influence the selection of bone mineral measures to predict biomechanical properties of vertebral bodies. DXA and QCT were employed to scan twenty-four male cadaveric vertebral bodies of humans for bone mineral content (BMC) and aBMD measures, and vBMD measures, respectively.

A biomechanical study on the effect of lengthening magnitude on spine off-loading in magnetically controlled growing rod surgery: Implications on lengthening frequency.

To assess whether the magnitude of lengthening in magnetically controlled growing rod (MCGR) surgeries has an immediate or delayed effect on spinal off-loading. 9 whole porcine spines were instrumented using two standard MCGRs from T9 to L5. Static compression testing using a mechanical testing system (MTS) was performed at three MCGR lengthening stages (0 mm, 2 mm, and 6 mm) in each spine.

Rapid external erosion of coral substrate in subtropical Hong Kong waters.

Erosion of coral substrate plays a crucial role in reef calcium carbonate budget, but little is known about erosion in subtropical corals. In a 2-year study of coral substrate erosion, we deployed Porites skeletal blocks at nine sites across subtropical Hong Kong waters. External erosion varied from 0.

Clay-based nanocomposite hydrogel with attractive mechanical properties and sustained bioactive ion release for bone defect repair.

Although clay-based nanocomposite hydrogels have been widely explored, their instability in hot water and saline solution inhibits their applications in biomedical engineering, and the exploration of clay-based nanocomposite hydrogels in bone defect repair is even less. In this work, we developed a stable clay-based nanocomposite hydrogel using 4-acryloylmorpholine as the monomer. After UV light illumination, the obtained poly(4-acryloylmorpholine) clay-based nanocomposite hydrogel (poly(4-acry)-clay nanocomposite hydrogel) exhibits excellent mechanical properties due to the hydrogen bond interactions between the poly(4-acryloylmorpholine) chains and the physical crosslinking effect of the nanoclay.

Metformin Hydrochloride Encapsulation by Alginate Strontium Hydrogel for Cartilage Regeneration by Reliving Cellular Senescence.

Cartilage lesion is a common tissue defect and is challenging in clinical practice. Trauma-induced cellular senescence could decrease the chondrocyte capability of maintaining cartilage tissue regeneration. A previous investigation showed that, by controlling the cellular senescence, the cartilage regeneration can be significantly accelerated.

Lingzhi and San-Miao-San with hyaluronic acid gel mitigate cartilage degeneration in anterior cruciate ligament transection induced osteoarthritis.

Objective: To investigate the mitigate efficacy of Chinese medicine Lingzhi (LZ) and San-Miao-San (SMS) combined with hyaluronic acid (HA)-gel in attenuating cartilage degeneration in traumatic osteoarthritis (OA).

Methods: The standardized surgery of anterior cruciate ligament transection (ACLT) was made from the medial compartment of right hind limbs of 8-week-old female SD rats and resulted in a traumatic OA. Rats (n ​= ​5/group) were treated once intra-articular injection of 50 ​μl HA-gel, 50 ​μl HA-gel+50 ​μg LZ-SMS, 50 ​μl of saline+50 ​μg LZ-SMS and null (ACLT group) respectively, except sham group.

Bioinspired Multichannel Nerve Guidance Conduit Based on Shape Memory Nanofibers for Potential Application in Peripheral Nerve Repair.

Repairing peripheral nerve injury, especially long-range defects of thick nerves, is a great challenge in the clinic due to their limited regeneration capability. Most FDA-approved nerve guidance conduits with large hollow lumen are only suitable for short lesions, and their effects are unsatisfactory in repairing long gaps of thick nerves. Multichannel nerve guidance conduits have been shown to offer better regeneration of long nerve defects.

Failure mechanisms of pedicle screws and cortical screws fixation under large displacement: A biomechanical and microstructural study based on a clinical case scenario.

Study Design: Cadaveric biomechanical with imaging analysis.

Objective: This study aims to compare the fixation failure between pedicel screws (PS) and cortical screws (CS), thus to investigate their failure mechanisms under vertical migration.

Summary Of Background Data: Due to their minimal invasive nature, CS are gaining popularity.

A novel mechanical parameter to quantify the microarchitecture effect on apparent modulus of trabecular bone: A computational analysis of ineffective bone mass.

Background: One of the characteristics of osteoporotic bone is the deterioration of trabecular microarchitecture. Previous studies have shown microarchitecture alone can vary the apparent modulus of trabecular bone significantly independent of bone volume fraction (BV/TV) from morphological and topological perspectives. However, modulus is a mechanical quantity and there is a lack of mechanical explanatory parameters.

Prevent action of magnoflorine with hyaluronic acid gel from cartilage degeneration in anterior cruciate ligament transection induced osteoarthritis.

According to the Chinese medicine, magnoflorine exerted significant anti-inflammatory effects and potentially promoted synthesis of proteoglycans in chondrocytes to reverse the progression of rheumatoid arthritis. However, the latent beneficial effect of magnoflorine for the treatment of traumatic osteoarthritis (OA) is still unknown. Therefore, we aim to demonstrate the efficacy of magnoflorine combined with HA-gel in attenuating cartilage degeneration in anterior cruciate ligament transection (ACLT) induced OA rat model.

Multifunctional fibrous scaffolds for bone regeneration with enhanced vascularization.

Due to the structural similarity to the extracellular matrix of human tissue and the ultra-high surface area-to-volume ratio, three dimensional electrospun fibrous structures have been increasingly used as tissue engineering scaffolds. Given that successful bone regeneration requires both good osteogenesis and vascularization, producing scaffolds that have both osteogenic and angiogenic potential is highly desirable. In this investigation, tricomponent fibrous scaffolds simultaneously incorporated with recombinant human vein endothelial growth factor (rhVEGF), recombinant human bone morphogenetic protein-2 (rhBMP-2) and bioactive calcium phosphate (Ca-P) nanoparticles are produced through a novel multi-source multi-power electrospinning method, and sequential growth factor release with a quick rhVEGF release and a steady rhBMP-2 release is achieved.

The measured mechanical properties of osteoporotic trabecular bone decline with the increment of deformation volume during micro-indentation.

Purpose: Osteoporosis is a critical global health issue. However, the biomechanical properties of osteoporotic trabecular bone have not been well understood due to its hierarchically complex structure mingled with accumulated microcracks. Previous studies indicated the mechanical behaviors of trabecular bone may differ with varying amounts of deformation.

Precisely Controlled Delivery of Abaloparatide through Injectable Hydrogel to Promote Bone Regeneration.

Side-effects from allograft, limited bone stock, and site morbidity from autograft are the major challenges to traditional bone defect treatments. With the advance of tissue engineering, hydrogel injection therapy is introduced as an alternative treatment. Therapeutic drugs and growth factors can be carried by hydrogels and delivered to patients.

Three-Dimensional Printing of Biodegradable Piperazine-Based Polyurethane-Urea Scaffolds with Enhanced Osteogenesis for Bone Regeneration.

Synthetic biodegradable polymeric scaffolds with uniformly interconnected pore structure, appropriate mechanical properties, excellent biocompatibility, and even enhanced osteogenesis ability are urgently required for in situ bone regeneration. In this study, for the first time, a series of biodegradable piperazine (PP)-based polyurethane-urea (P-PUU) scaffolds with a gradient of PP contents were developed by air-driven extrusion 3D printing technology. The P-PUU ink of 60 wt % concentration was demonstrated to have appropriate viscosity for scaffold fabrication.