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Abstract:In active health, biomechanics plays an irreplaceable role. Exercise creates mechanical stimulation to human tissues and organs. It promotes health, or causes injury and disease. In addition, biomechanics is involved in the design and evaluation of assistive devices, as well as in rehabilitation clinical diagnosis and treatment. The development of active health biomechanics requires the integration of sports and medicine. It includes more dynamics, fatigue and mechanical coupling issues. In the future research, on the one hand, the experience of other directions in biomechanics should be learnt from. On the other hand, it is necessary to combine the frontiers of scientific and technological development to develop new directions in biomechanics.

Abstract:Objective To design a kind of customized insole with zonal gradient hardness for people with high arch foot in need of plantar decompression. Methods A functional gradient structure was designed and applied to the customized insole. Porous elements with corresponding elastic modulus were used in different areas of insole. The relationship between structural element parameters and modulus was studied through mechanical tests. The foot geometry and plantar pressure distribution data of volunteers were collected, and the plantar region was divided according to the pressure contour line, so as to assemble the structural unit. Four kinds of customized insoles were designed: ordinary flat insole, optimized flat insole, ordinary full contact insole and optimized full contact insole. Through plantar pressure test experiment, the optimization design of sub region was verified. Results The designed insole could reduce the peak pressure of high arch foot by 52.8% in static standing state and 18.43% in gait condition. Conclusions This method can be used to design customized insoles, such as functional insoles for patients with diabetes and high arch feet, by providing better decompression function. The research findings provide references for conservative treatment of foot diseases with decompression needs.

Abstract:Objective To analyze the difference in ground reaction force (GRF) between male and female runners and between left and right limbs using the one-dimensional statistical parametric mapping (SPM). Methods Thirty male and female runners participated the running test on force treadmill at the speed of 12 km/h. GRF of consecutive five steps were recorded. The independent-sample t test and paired-sample t test in the SPM package were used to check the male vs female and right limb vs left limb differences. Results Male and female runners showed inter-limb asymmetry in vertical average loading rate (VALR), and the VALR of male runners was significantly higher than that of female runners in the left limb, while no significant differences were found in the right limb. Male and female runners showed significant differences in the right vertical GRF during push-off and medial-lateral GRF during landing, while left medial-lateral GRF presented significant differences during landing and mid stance. Male runners showed right limb vs left limb significance in the anterior-posterior GRF during push-off, vertical GRF during landing and push-off and medial-lateral GRF during landing, while female runners exhibited right limb vs left limb significance in vertical GRF during landing and push-off. Conclusions This study introduced the application of SPM in statistical analysis of GRF, elaborated the procedures and theory, compared the test of time-series data in SPM and discrete value with traditional statistics, and discussed the difference and features in SPM and SnPM, thus providing references for the application in data analysis of sports biomechanics. Comparison in the male vs female and right limb vs left limb revealed the genders and inter-limb symmetrical differences in the landing, mid-stance and push-off phases during stance. The research findings laid the foundation for future investigation of mechanism in running related injuries and strategy of prevention and treatment.

Abstract:Objective Based on ergonomics and biomechanics simulation technology, the biological evaluations of human muscles and the rehabilitation strategies of foot rehabilitation robot with adjustable swing were carried out and studied. Methods The human-robot coupling model of human body and foot rehabilitation robot with adjustable swing were established by using AnyBody software. Through kinematics simulation of the coupling model, the comparison between the simulation result and the theoretical calculation result confirmed reliability of the coupling model. The parameter study of AnyBody software was used to perform the biomechanical simulation of the verified coupling model. By regarding velocity and swing of the foot rehabilitation robot as variables, the muscle activity and muscle force under different combinations of variables were analyzed. ResultsDuring rehabilitation exercise, stretching performance of the foot related-muscles was effectively trained. The influence of different velocity and swing amplitude on muscles was different, and safety range of the velocity and swing adjustment was obtained. Conclusions The combined analysis of muscle activity and muscle force under different velocity and swing was achieved. The results have certain guiding significance on clinical application of foot rehabilitation robot and formulation of rehabilitation strategies in passive rehabilitation mode.

Abstract:Objective To establish the biomechanical model of skeletal muscle during hand grasping for reverse dynamics simulation, so as to obtain the maximum muscle force of each muscle involved in the process of hand grasping under different forces. Methods CT scanning was performed on a volunteer’s hand, and CT data of his hand were imported into Mimics software for 3D reconstruction, so as to obtain the bone models of each segment. After adjusting the model coordinates by Geomagic Studio, the model was imported in AnyBody software for establishing the kinematics model of the hand skeleton. The related muscles involved in the flexion of each finger were added, to establish the skeletal muscle model of the hand. The model was then used to simulate the reverse dynamics of hand grasping. ResultsThe maximum muscle force of each muscle in the whole process of finger movement was obtained after the 5-30 N external force was applied to each distal phalanx. With the increase of force, the maximum muscle force of each muscle showed a linear trend. For example, the maximum muscle force of flexor pollicis longus increased from 18.49 N to 110.93 N; when the external force was 5 N, the maximum muscle force of flexor pollicis brevis, flexor pollicis longus, adductor pollicis and flexor digiti minimi brevis during hand grasping was 7.70, 18.49, 9.49, 8.39 N, respectively. The muscle force of superficial and deep flexors was greater than that of other muscles in the process of finger movement, which played a major role in grasping the hand. Conclusions The maximum muscle force of the muscles involved in hand grasping under different resistance, and the relationship between muscle force of main muscles and joint angles, can provide guidance and references for the evaluation of hand rehabilitation effect of stroke patients, as well as certain theoretical basis for the manufacture of rehabilitation equipment.

Abstract:Objective To compare the differences in lower limb joint kinematics and muscle activation between Asian squat (AS) and Western squat (WS). Methods Eleven healthy adults were recruited to complete the biomechanical test of AS and WS. The 3D motion analysis system, force plates and surface electromyography (EMG) were used to collect kinematics, kinetics and muscle activation data of the subjects during two squats, and muscle force of the lower limb was also calculated by OpenSim. Results AS showed pelvis forward flexion, while WS showed pelvis backward extension at the time of peak knee flexion angle. Compared with the AS, a significant smaller hip flexion, larger knee flexion, larger hip abduction and hip rotation angles were found in WS at the time of peak knee flexion angle. Compared with AS, a significant greater peak force of soleus was found in WS during descent and ascent phases of squat. Additionally, a smaller peak force of anterior tibia was found in WS than that in AS during descent and ascent phases of the squat. No significant differences were found in other muscle peak force and the time of peak force between AS and WS. Conclusions The combined tibialis anterior activation and proximal joint flexion might be beneficial to stabilization during AS. The soleus muscle activation was significant in WS with heel lifting. The muscle activation pattern of proximal joint was similar between AS and WS. This study provides theoretical guidance for the design of clinical squat rehabilitation programs or the selection of squat training.

Abstract:Objective To analyze gait characteristics of patients with spastic cerebral palsy (CP) before and after functional selective posterior rhizotomy (FSPR) surgery, so as to evaluate curative effects of the surgery objective ly. MethodsFifteen patients with spastic CP to be treated by FSPR were selected. The VICON three-dimensional (3D) motion analysis system and AMTI 3D force plates were used to collect and analyze the spatiotemporal gait parameters, kinematic and dynamic parameters before and after FSPR surgery. Results After the surgery, the left and right support phases were longer,and the left-side step length was significantly larger. The step height, velocity and the max displacement of center of gravity (COG) in coronal plane were smaller than those before surgery.The sagittal plane angle (flexion and extension angle) of the knee during initial landing was significantly increased, while no significant differences were found in that of the hip and ankle.The range of motion (ROM) of the left/right hip, knee and ankle in sagittal plane was increased to some extent during walking, with statistical differences. The ROM of right ankle in coronal plane was also increased obviously. The minimum flexion angle of the right knee and the maximum plantar flexion angle of the left/right ankle were significantly reduced. The maximum vertical forces of left and right support phases were significantly increased, while no significant differences were found in torque of lower limbs. Conclusions The 3D gait analysis can be used to evaluate the effect of FSPR on patients with spastic CP. The spasticity of patients with spastic CP is relieved after FSPR surgery, and the spatiotemporal gait parameters and kinematics parameters are improved significantly. But the improvement of dynamic parameters was not obvious, and further rehabilitation treatment is needed.

Abstract:Objective To investigate the influence of Tai Chi posture on knee joint load and the strategy of coordinated muscle contraction. Methods Twenty Tai Chi practitioners with more than 3 years of Tai Chi practice was recruited. By using high-speed motion capture system andthree-dimensional force plate, the adduction angle, tibial angle, joint force, joint torque of the supporting leg during the Tai Chi step lunge movement were collected, and the quadriceps and gastrocnemius muscle strength were obtained through simulation method. The muscle strength performance, recruitment mode and activation method of baseline step, toe-out step and toe-in step were compared. ResultsThe tibial angle and adduction force increased in the toe-out step but those parameters in the toe-in step remained unchanged; the strength of the medial femoris, semimembranosus, semitendinosus and lateral gastrocnemius muscle increased in the toe-out step; the external femoral muscle and medial gastrocnemius muscle increased in the toe-in step. The gastrocnemius muscle was preferentially activated than the quadriceps muscle, and the way of muscle recruitment changed. Conclusions Tai Chi posture will change the way of muscle force recruitment and affect the knee joint function. Standardized movements can be used as the reference for osteoarthritis exercise therapy and have some significance in clinical application.

Abstract:Objective To investigate the effects of shoes type (barefoot, ordinary running shoes, minimalist shoes) and walking speed (jogging, walking at normal speed) on biomechanical parameters of knee joint, so as to provide theoretical reference for scientific fitness. Methods Vicon three-dimensional （3D） motion capture system and Kistler 3D force plate were used to collect biomechanical parameters of lower limbs from 10 subjects during walking at different speed with different shoes. Two-way (2 walking conditions × 3 shoe conditions) repeated measures analysis of variance was used to statistically analyze each dependent variable. Results Compared with jogging, the lateral excursion of plantar center of pressure (COP) was greater, the moment arm in frontal plane, the adduction moment and peak loading rate of knee joint were smaller, but the angular impulse of knee joint in frontal plane was greater. Compared with ordinary running shoes, the stride length was decreased, the lateral excursion of COP was greater, and the moment arm of knee joint in frontal plane, the knee adduction moment, the peak load rate and the angular impulse of knee joint in frontal plane were smaller. Conclusions In order to reduce the angular impulse and peak loading rate of knee joint in frontal plane, it is recommended to jog with small strides for ordinary people with minimalist footwear.

Abstract:Objective To study the constitutive model of adipose tissue at medium strain rate and its parameter inversion. Methods Based on experiments of adipose tissue mechanical properties, the compression experiment of adipose tissues was reconstructed by finite element method, and the parameters for characterizing constitutive models of adipose tissues were screened. Combined with the method of feasible direction (MFD) in optimization method, the reverse calculation for parameters of fat tissue constitutive model at medium strain rate was conducted. ResultsCompared with Ogden constitutive model, the viscoelastic constitutive model was more suitable for characterizing the mechanical response at medium strain rate (260 s-1). The parameters of the constitutive model suitable for simulation were obtained using the reverse method. Conclusions The viscoelastic constitutive model was more suitable for characterizing the mechanical response at medium strain rate. The results provide references for studying the influence of human adipose tissues on body injury in finite element simulation of vehicle collisions.

Abstract:Objective To propose a one-way fluid-structure interaction (FSI) method based on an idealized aortic dissection model, so as to analyze the hemodynamics and wall stress in the false lumen (FL) under the influence of multiple overlapping uncovered stents (MOUS). Methods Upon establishment of the numerical model, the models were divided into two categories according to whether the model involved FL perfused branch artery. The characteristics of hemodynamics and wall stress state in the post-operative scenarios were simulated under different surgical strategies. The wall stress state of the FL before and after thrombosis formation was also compared and analyzed. ResultsThe release process of the stents had little influence on wall stress of the FL. The high velocity and high wall shear stress (WSS) area in the FL could not be reduced by using the MOUS alone. If only the proximal entry tear was blocked with a covered stent-graft, the distal end would maintain a region of high flow rate and high WSS. The combination of covered stent-graft and MOUS would result in a region of low flow rate and low WSS, as well as reduced wall pressure and wall stress in the FL. Compared with the model with FL perfused branch arteries, the model without it was more likely to form a region of low flow rate and low WSS after surgery. However, blood pressure in the FL was relatively higher. The formation of thrombus in the FL could greatly reduce wall stress in the area covered by the thrombus. Conclusions The method proposed in this study can simultaneously investigate hemodynamics and wall stress characteristics of the FL, and provide support for studying mechanical mechanism of FL thrombolysis induced by MOUS and the post-operative aortic expansion.

Abstract:Objective To measure mechanical properties of calcified tissues from human aortic valve by nanoindentation test. Methods Leaflets from 5 patients with aortic stenosis were collected. Elastic modulus and hardness of the calcified leaflets were obtained by nanoindentationtest. Results The elastic modulus and hardness of the calcified leaflets were (15.69±3.89) GPa and (0.59±0.15) GPa, respectively. Conclusions The elastic modulus and hardness of the calcified valve tissues can be obtained by nanoindentationtest, which provides experimental data for biomechanical research of the valve.

Abstract:Objective To explore hemodynamic performance of the aortic dissection after lesions, so as to provide a more scientific basis for patient treatment. Methods Based on computed tomography angiography (CTA) image data from a patient with complex Stanford B-type aortic dissection, the personalized aortic dissection models with different rupture shapes (H-type, O-type, and V-type) at proximal end of the aortic dissection were established. Combined with computational fluid dynamics (CFD) and morphological analysis method, distributions of the velocity at rupture section, the blood flow, the wall pressure and the wall shear stress (WSS) were analyzed. Results The flow velocity, the highest pressure difference and the WSS proportion at entrance of the H-shaped rupture showed larger hemodynamic parameters than those of the other two types. The risk of dissection rupture for type H was the largest, while type V was in the middle, and type O was the smallest. Conclusions This study provides an effective reference for further numerical analysis the cases and formulation of treatment plans.

Abstract:Objective To compare biomechanical properties of the traditional and novel locking compression plate （LCP） for treating femoral shaft fracture, so as to provide theoretical basis for selecting more effective bone plate. Methods The bending strength and fatigue tests on the plate were performed, and the finite element analysis on deformation, stress and life of the plate were conducted by using ANSYS Workbench. Results The average bending yield load and bending strength of the novel LCP were 1.4 times of that of the traditional LCP, and the average cycle times of the novel and traditional LCP were 106 and 47 091, respectively. The difference of service life for two LCPs was 33.8%. ConclusionsThe failure probability of the novel LCP is smaller than that of the traditional LCP, and the novel LCP has more effective biomechanical stability.

Abstract:Objective To investigate the characteristics of knee kinematics and ground reaction force (GRF), as well as the stress state of cartilage and meniscus in the process of lateral incisions at different cutting angles under expected conditions. Methods Kinematics and GRF data of 14 subjects at 45°, 90° and 135° cutting angle respectively under expected conditions were collected. The knee joint reaction force was obtained through the inverse dynamics calculation of Visual 3D. Based on three-dimensional (3D) finite element model of the knee joint, the contact process at 3 lateral cutting angles was simulated. ResultsUnder expected conditions, there were significant differences in knee joint kinematics characteristics at 3 cutting angles during contact process(P＜0.001), and the knee flexion increased with the cutting angle increasing; the vertical GRF decreased significantly with the cutting angle increasing (P＜0.001), while the horizontal GRF showed the opposite trend; for 3 cutting angles, the peak contact stress of patellar cartilage and femoral cartilage was larger at 90° cutting angle, the peak principal stress at anterior cruciate ligament (ACL) contact point was also larger at 90° cutting angle, and the following was at 135° and 45° cutting angle, respectively; the peak contact stress of lateral femoral cartilage was larger than that of medial femoral cartilage at 3 cutting angles. Conclusions The risk of knee joint injury is higher at 90° cutting angle, and the stress state of knee joint at 135° cutting angles is better than that at 90° cutting angle, and the risk of knee joint injury does not increase with the increase of cutting angle under expected conditions.

Abstract:Objective To establish the pushing transmission model of tendon-sheath system (TSS) for endoscopic flexible instrument, and study the key influencing factors of transmission efficiency. Methods The force and displacement transmission models of TSS in pushing configuration were built and simulated. The tendon-sheath transmission testing platform was designed to validate the model. The influencing factors, such as transmission velocity, tendon-sheath diameter ratio, curvature radius, were explored using this setup. Results There were obvious nonlinear phenomenon in force and displacement transmission. The model simulation results accorded quite well with the experiment results. Transmission velocity, tendon-sheath diameter ratio, curvature radius all had great effects on pushing force transmission of endoscopic flexible instrument, while they had a smaller effect on displacement transmission. Conclusions The proposed model can be used for calculating pushing force transmission of tendon-sheath system for endoscopic flexible instrument, so as to provide the doctors with force feedback at the tip of the end effector, and ensure the safe operation and improve the surgical effects. For better design and control of endoscopic flexible instrument, the transmission velocity, tendon-sheath diameter ratio, curvature radius must be comprehensively considered.

Abstract:Objective To design a personalized titanium mandibular prosthesis with porous and support structure, and analyze its stress distribution characteristics through finite element analysis, so as to evaluate clinical value and prospect of the prosthesis. Methods The fourth mandibular premolar and molar from the right mandible of Beagle dogs were removed. The spiral CT was taken after three-month healing, and the three-dimensional (3D) model of the mandible was established. Resection of 3 cm mandible with simulated surgical procedure and reconstruction with personalized restoration were conducted. The prosthesis consisted of abutment, pillar, solid unit, porous unit and retention unit. A personalized titanium mandibular prosthesis finite element model A was established, to analyze the prosthesis stress under loading, and further study was proceeded when the maximum stress of each part constituting the prosthesis was smaller than yield strength of its material. The finite element model B with the assembly of the prosthesis, mandible and screw was constructed and loaded with the mastication force, and the stress, strain and displacement distributions of the mandible were recorded. Results When the abutment was under 100 N vertical loading, the peak stress of the prosthesis with solid structure and porous structure was 147.03 and 75.36 MPa, respectively, which was smaller than yield strength of its material; the peak stress of the cortical bone and cancellous bone was 53.713, 4.216 7 MPa, and the strain was 3.753 6, 3.562 5, respectively; the maximum displacement of the restoration was 338.3 μm. ConclusionsTaking the canine mandible as an example, the personalized prosthesis with porous and support structure shows the uniform stress distribution and good mechanical properties through finite element analysis. The results provide a new method for the design of prosthesis for repairing mandibular defects.

Abstract:Objective To study movement process of circulating tumor cells (CTCs) in the blood and mechanism of CTC capture by CellCollector, and reveal relationship between the detected CTC numbers and the actual CTC concentration in the body. Methods Based on Fluent and EDEM software, the unidirectional fluid-solid interaction method was applied to establish a two-phase flow model, including the hemodynamic model and the CTC transport model, and capture simulations under different CTC concentration conditions were conducted. Results The number of CTCs captured by CellCollector was significantly positively correlated with the CTC concentration in the body. When the CTC concentration was low, CTCs could only be captured in several time intervals, and the capture had a certain contingency; as the concentration increased, the uniformity of CTC capture over time became better, and the total number of captures also increased. Conclusions Through the fitting of simulation results, analytical quantitative relationship between the captured CTC number and the CTC concentration in the body is preliminarily given, which provides theoretical basis and mechanical explanation for the clinical use of CellCollector.

Abstract:Objective The ileum of porcine intestines with radiofrequency (RF) energy was fused through a novel linkage-type pressure controlled electrode, so as to verify feasibility and security of intestinal reconstruction in the RF energy tissue fusion technology. Methods Fresh porcine intestines were fixed on negative electrode in the order of ‘mucosa-serosa’, and then different compressive pressures （497，796，995，1 194，1 492 kPa）and RF energy were applied to the tissues through positive electrode of pressure cone to complete intestinal anastomosis. Biomechanical properties of the fused area were studied by tensile strength and bursting pressure test, and the thermal diffusion and tissue microstructure also studied. ResultsThe anastomotic tensile strength and bursting pressure could reach （8.73±1.11） N and （8.29±0.41） kPa, respectively, when the energy output power, pressure and welding time were 160 W, 995 kPa and 13 s, respectively, and an intact microstructure with little free collagen in the fused area could be observed. Conclusions The technology of RF energy-based tissue fusion could accomplish fast and stable intestinal tract reconstruction, showing great potential in clinical application. It is of great significance to shorten the operation time, simplify the operation process and improve the operation quality.

Abstract:Objective To investigate the mechanical properties of Achilles tendon (AT) during running under different shoe conditions (minimalist vs conventional shoes). MethodsSixteen healthy male runners with habitual rearfoot strike patterns were recruited to complete the running trials at the speed of 3.16~3.50 m/s under two shoe conditions. The cross-sectional area of the AT was obtained by ultrasound imaging. Sagittal plane ankle kinematics and ground reaction forces were recorded by motion capture system and three-dimensional force platform simultaneously. Mechanical properties of the ankle and AT were calculated. Paired t test was used to compare the effects of two shoe conditions on various parameters (ankle angle, strike angle, AT force, stress, strain, etc). ResultsCompared with conventional shoes, foot inclination angle was significantly reduced by 39.9% with minimalist shoes. Obvious increase in ankle moment, peak AT force, peak AT loading rate, average loading rate, and obvious decrease in time to peak AT force were observed with minimalist shoes. Peak AT stress, peak AT strain and corresponding stress rate, peak strain rate also increased significantly with minimalist shoes. ConclusionsGreater AT loading was observed when runners with habitual rearfoot strike pattern in conventional shoes begin to wear minimalist shoes. Therefore, a gradual transition to minimalist shoes was recommended for them so as to improve the ability to load adaptively.

Abstract:Objective To explore the influence of biomechanical characteristics of badminton players on sports risk at the moment of foot and ankle landing, so as to provide references basis for avoiding the sports risk of high-frequency and high-intensity landing of ankle joint of beginners. Methods Using three-dimensional force measuring platform and motion capture system, the kinematic and dynamic data of 30 badminton beginners (experimental group) and 30 high-level athletes (control group) at the kick-off (1 step) moment during ankle landing were collected. Results The angles of metatarsal flexion and dorsiflexion in experimental group were significantly smaller than those in control group, and the angles of varus and internal rotation in experimental group were significantly larger than those in control group. The left-right forces in experimental group were significantly larger than those in control group, and there was no significant difference in anterior-posterior force and vertical force between experimental group and control group. The valgus and external rotation torque of experimental group were significantly higher than those of control group, and the internal rotation torque of control group was significantly higher than that of experimental group. Conclusions Compared with beginners, the ankle movement of professional athletes has good dynamic stability and flexibility, the cushioning task can be completed with a smaller range of movement and force in left-right direction, and the angle of metatarsal flexion and dorsiflexion of professional athletes is relatively increased. It is also the embodiment of good training effect, so that the buffer time is slightly longer to prevent the impact of sudden landing of the ankle.

Abstract:Advanced glycation end-products (AGEs) are the products of non-enzymatic reactions between free amino groups of macromolecules and reducing sugars. AGEs accumulation in bone tissues changes the activity and function of bone cells by binding to their surface receptors, causing abnormalities in the process of bone remodeling. AGEs accumulation can also change the original structure and mineral deposition of bone collagen, affect the micro-mechanical properties of bone tissues, and further reduce bone strength and toughness, increase the bone fracture risk, which will lead to bone diseases and do great harm to human health. This article summarized the causes of AGEs and their detection methods, and reviewed previous studies about the effects of AGEs accumulation on bone biomechanics at micro and macro levels, so as to provide references for the early diagnosis and treatment of bone diseases in clinic.

Abstract:Bone homeostasis is a relative balance between bone formation and resorption. Signal transducer and activator of transcription 3 (STAT3), which is closely related to bone homeostasis, takes part in multiple intracellular and extracellular signal pathways. STAT3 participates in the process of osteoblast differentiation regulated by several factors. It can also maintain bone homeostasis by regulating the recruitment, differentiation and activation of osteoclasts. In addition, STAT3 is involved in the interaction between osteoblasts and osteoclasts. Patients with STAT3 mutations can have several inherited bone metabolism diseases. Furthermore, STAT3 plays a critical role in load-driven bone remodeling. Mechanical stimulation promotes osteoblast differentiation and bone formation through activating or enhancing STAT3 expression during bone remodeling process. This review summarizes the participation of STAT3 in maintaining bone homeostasis together with its possible mechanisms and discusses the connection between STAT3 and mechanical stimulation in bone remodeling, so as to provide a potential pharmacological target for the treatment of bone diseases.

Abstract:Osteocytes are the main mechanical sensory and transductive cells of bone tissues. They connect with each other through many synaptic structures to form a huge regulatory network of bone steady-state cells, which are connected with osteoblasts, osteoclasts and other bone matrix surface cells. Osteocytes regulate bone metabolism and maintain bone regeneration by affecting osteoblast bone formation and osteoclast bone resorption through paracrine pathway. Aiming at the effects of some signal molecules or protein factors secreted or released by osteocytes after mechanical stimulation on the growth and differentiation of osteoblasts and osteoclasts, this paper reviews recent advances in how mechanically stimulated osteocytes communicate with osteoblasts and osteoclasts, so as to provide new ideas for the study of osteocytes biomechanics.

Abstract:Titanium mesh cage is one of the fusion devices used in anterior cervical corpectomy and fusion (ACCF). It can not only immediately rebuild the stability of cervical spine during the operation, maintain the height and physiological curvature of intervertebral vertebrae, but also avoid the complications of bone donor area caused by autologous bone extraction. Therefore, titanium mesh cage has become the most commonly used internal plant in ACCF. However, there exist many problems in traditional titanium cage, such as stress shielding and titanium cage sinking, which will affect the surgical effect to a certain extent, and even lead to serious postoperative complications requiring revision surgery. At present, a variety of new titanium cages have been invented, which can solve the problems caused by traditional titanium cage to a certain extent. Biomechanical evaluation and its testing methods are an indispensable process for judging whether a new type of spinal fusion cage can be used in clinical practice. This article reviews the biomechanical studies related to cervical spine anatomy, the biomechanical properties of traditional titanium cages and new titanium cages, so as to provide new ideas for the improvement of traditional titanium cages and the development of new titanium cages.