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Objective To construct a three-dimensional (3D) dynamic head-neck finite element model which ac cords with the anatomical structure,and study its dynamic responses under the extemal force.Methods By using the neck CT images of a Chinese adult male volunteer and obtaining the 3D cervical point cloud data,the finite element model of cervical spine was established using ICEM-CFD and HyperMesh software.This model,including vertebrae,intervertebral discs,facet joints,ligaments and cartilage tissues,and combining with the es tablished and verified head finite element model,was assembled as human head-neck finite element model with detailed anatomical structures.Results The model was validated by data of head-neck axial impact experiments reported in previously published literature.The simulation results showed that the neck deformation,head acceleration,head force and injury positions were preferably consistent with the experimental data.Conclusions The established 3D dynamic finite element model can be used to study head-neck dynamic responses and damage mechanism in the fields of traffic safety and impact injuries.
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Objective To construct a three-dimensional (3D) dynamic head-neck finite element model which accords with the anatomical structure, and study its dynamic responses under the external force. Methods By using the neck CT images of a Chinese adult male volunteer and obtaining the 3D cervical point cloud data, the finite element model of cervical spine was established using ICEM-CFD and HyperMesh software. This model, including vertebrae, intervertebral discs, facet joints, ligaments and cartilage tissues, and combining with the established and verified head finite element model, was assembled as human head-neck finite element model with detailed anatomical structures. Results The model was validated by data of head-neck axial impact experiments reported in previously published literature. The simulation results showed that the neck deformation, head acceleration, head force and injury positions were preferably consistent with the experimental data. Conclusions The established 3D dynamic finite element model can be used to study head-neck dynamic responses and damage mechanism in the fields of traffic safety and impact injuries.
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Objective To explore the effects of intensive therapy program on gross motor function of children with spastic cerebral palsy. Methods Thirty 3-15 year old children with spastic cerebral palsy and level I-III in gross motor function classification system (GMFCS) were randomly divide into 2 groups. The trial group adopted intensive therapy program for treatment, including functional dynamic suit and universal exercise unit combined with functional movement training. The control group adopted core stability training for treatment. Children in two groups took a 1-month training program for 3 hours per day and 5 days per week. The pediatric evaluation of gross motor function measure (GMFM-66) and peabody developmental motor scale (PDMS-2) were administered before and after treatment. Results The scores of GMFM-66 as well as the stationary and locomotion scores of PDMS-2 in both groups showed significant differences within group (P<0.01) after treatment. For the scores of GMFM and PDMS-2 between two groups, no significant differences were found. Conclusions The intensive therapy program can improve the gross motor function of children with spastic cerebral palsy and gain the same effects as core stability training, which can provide a novel and effective intervention for children with cerebral palsy.
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Objective To explore the effects of intensive therapy program on gross motor function of children with spastic cerebral palsy.Methods Thirty 3-15 year old children with spastic cerebral palsy and level Ⅰ-Ⅲ in gross motor function classification system (GMFCS) were randomly divide into 2 groups.The trial group adopted intensive therapy program for treatment,including functional dynamic suit and universal exercise unit combined with functional movement training.The control group adopted core stability training for treatment.Children in two groups took a 1-month training program for 3 hours per day and 5 days per week.The pediatric evaluation of gross motor function measure (GMFM-66) and peabody developmental motor scale (PDMS-2) were administered before and after treatment.Results The scores of GMFM-66 as well as the stationary and locomotion scores of PDMS-2 in both groups showed significant differences within group (P ＜ 0.01) after treatment.For the scores of GMFM and PDMS-2 between two groups,no significant differences were found.Conclusions The intensive therapy program can improve the gross motor function of children with spastic cerebral palsy and gain the same effects as core stability training,which can provide a novel and effective intervention for children with cerebral palsy.
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<p><b>OBJECTIVE</b>To analyze the relationship between position of head, cervical curvature type and associated cervical balance parameters in a neutral looking-forward posture.</p><p><b>METHODS</b>Cervical lateral X-rays of 60 patients with cervical spondylosis were selected from January to December 2015. There were 22 males and 38 females with an average age of (35.5±10.9) years old. The measured parameters included cervical curvature type, McGregor slope, C2 lower end plate slope, T1 slope, center of gravity to C7 sagittal vertical offset (CG-C7 SVA), and C2 to C7 sagittal vertical offset (C2-C7 SVA). The parameters were analyzed using Spearman correlation.</p><p><b>RESULTS</b>The cervical curvature type was significantly correlated with C2 lower endplate slope, C0-C2 angle (total degree of C2 lower endplate slope plus McGregor slope), CG-C7 SVA and T1 slope (<0.05), but it was not significantly correlated McGregor slope (>0.05). C2 lower endplate slope and C2-C7 SVA (r=0.87) were significantly (<0.05) correlated with CG-C7 SVA (<0.05).</p><p><b>CONCLUSIONS</b>There was certain some relationship among position of head, cervical curvature type and associated cervical balance parameters in a neutral looking-forward posture. The center of gravity of the head would backwards shift following faced upward. A position of extension with posterior-shifting of the head would suggest that it may be accompanied with a relatively normal lordosis of the cervical spine. Some patients with abnormal curvature showed slightly bended head in the natural posture. Health education toward these people would be meaningful to restore the balance of their neck.</p>
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Objective To construct a three-dimensional finite element model of human skull with anatomic structure and to study biomechanical responses of the head under various loading conditions. Methods The finite element model of high-precision human head with anatomic structure was reconstructed with the constitutive skull made from elastic-plastic material to simulate the fracture. This model was used to simulate frontal impact intracranial pressure testing, dynamic skull fracture testing and head drop testing reported by the literature, and the simulation reproduced the experimental process of head subjected to impact loads, skull fractures, and biomechanical responses of head fall at different speed. Results Under frontal impact loading, the model showed hedge-side positive-negative intracranial pressure distributions, and the occipital deformation was more serious than that in prefrontal, parietal under similar loading. The faster falling speed would cause more serious injuries. Conclusions To establish the accurate anatomic finite element model of human head can preferably simulate biomechanical responses of the head under the loading of impact and fall. Through quantifying parameters such as contact force and intracranial pressure, injury risks can be assessed to provide scientific references for design of protective devices.
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Objective To explore the mechanism of ankle sprain varus, a kind of human ankle brace with asymmetric physiological structure which can protect the ankle effectively is designed. Methods The anatomic factors of ankle varus were analyzed firstly, and a kind of ankle brace with asymmetric structure was designed based on asymmetric structure of ankle joint by anatomy. Using Kinect system and Geomagic Studio software, 3D scanning and digital modeling on ankle joint of a male adult were performed, and the ankle model was established by 3D printing technology. With EVA film, silica gel film and wrapped edge copper network as raw materials, two kinds of ankle brace with asymmetric structure were prepared by 3D draping and composite materials processing technology. The shaping properties, tensile properties, fatigue performance, outer fabric breathability and friction of the designed brace were tested. Results The outside of ankle brace with asymmetric structure had good shaping property, low tensile elastic recovery rate. Under the effect of repeated small load, EVA composite materials and silicone composite materials could keep good elastic recovery and effectively bear external varus forces. The results from air permeability and grinding test showed that polyester material was a kind of suitable fabrics for the outer lining material. Conclusions The mechanical properties of ankle brace with asymmetric structure can meet the requirement of ankle varus protection. The fabric of ankle brace can improve moisture permeability and frictional properties.
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Ankle sprains are one of the most common surgical injuries in clinic. In this article, the foot anatomy structure was elaborated, and the biomechanics of ankle ligaments during sports was mainly reviewed. At the same time, the mechanism of ankle sprains was analyzed, the principal means of ankle sprains, prevention and rehabilitation at present were summarized, and the use of ankle braces to prevent ankle sprains as well as its research progress were introduced emphatically. The classification and characteristics of ankle braces were then summarized, and the prevention of ankle sprains and development of ankle braces were prospected. The multiple ankle lateral ligament damage was due to the physiological structure differences between lateral and medial ligaments of the ankle joints, and such structure characteristic should be considered while improving ankle braces and designing new ankle braces. Wearing ankle braces plays a key role in ankle sprains protection, which can shorten the recovery time and avoid re-injury in clinical rehabilitation. For rehabilitation of severe ankle sprains, semi-rigid ankle braces are better than elastic ones.
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Manual therapy is one of the effective methods in treating neck pain. It has certain advantages in the short term to ease the symptoms of neck pain. In recent years, using different mechanical sensors and imaging equipment with computer software, the researchers found the difference of cervical activity between health adult and patients with neck pain. They also analyzed the kinematics, magnitude of force, stress and strain of the related structure and other mechanical parameters during cervical manipulation. These biomechanical researches revealed the functional anomaly caused by neck pain, reflect the safety of cervical manipulation, explain the abnormal stress of neck pain and the adjusting role of manipulation. Relatively speaking, these studies are too basic, and their analysis also are limited for the stress and strain about internal tissue. Study to aim directly at above problems will have important significance in understanding neck pain and standardizing manipulation therapy.
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Traditional Chinese traumatology manipulation (TCTM) has some prominent advantage for treating cervical spine diseases in clinic, thus the biomechanical research on TCTM could possess important clinical and theoretical significance. The studies on biomechanical mechanism of TCTM for treating cervical spine diseases in recent years were reviewed from various aspects, and biomechanical issuessuch as the force measurement of TCTM, the different operation types of TCTM (i.e. tendon-soothing maneuver, bone setting manipulation), the TCTM effect on cervical tissues (i.e. vertebral body, intervertebral discs, muscles, blood vessels) were also investigated, trying to provide some biomechanics theoretical evidence and guidance for treating cervical spine diseases with TCTM in clinic.
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Objective To make comparative study on the immediate stability of intra-articular calcaneal fractures fixed by crossing screws and by plate. Methods A set of foot CT images from a normal male were collected to construct 3D finite element models of Scander-III calcaneau fracture fixed by crossing screws and by steel plate, respectively. The regular pattern of stress and displacement distributions on these two fracture models under vertical load of 700 N was analyzed. Results For the screw-fixed model, the stress was concentrated at the connecting area between screws and fracture ends, and the maximum stresses were different for screws at different places. While for the plate-fixed model, the stress was concentrated at the connecting area between plate and screw. The highest stress was concentrated in anterior segment of the plate. The maximum stresses of plate, screw and calcaneus were all lower than their shear strength. The displacements of intact calcaneus and fractures were concentrated on the posterior subtalar joints, and a larger displacement appeared on the internal part of joint facet. Conclusions Both crossing screws and steel plate can be used to fix calcaneal fractures with a preferable initial stability. Functional exercise and rehabilitation are recommended at early time after operation.
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<p><b>OBJECTIVE</b>The clinical effect of the Shi's cervical reduction technique for cervical spondylosis and related disorders has confirmed, however, there were few studies on the body motion during manipulation in vivo study. This study is to summary the law of motion and the motion characteristics of the right operation shoulder, elbow, knee and ankle joints by data acquisition and analysis with the 3D motion capture system.</p><p><b>METHODS</b>The markers were pasted on the head, trunk, left and right acromion, elbow joint, wrist joint inner side and the outer side of the inner and the outer side and the lateral upper arm, forearm lateral, anterior superior iliac spine, posterior superior iliac spine, trochanter, femoral and tibial tubercle, inner and outer side of knee, ankle, fibular head, medial and lateral in first, 2,5 metatarsal head, heel and dual lateral thigh the calf, lateral tibia of one manipulation practioner, and the subject accepted a complete cycle of cervical "Jin Chu Cao and Gu Cuo Feng" manipulation which was repeated five times. The movement trajectory of the practioner's four markers of operation joints were captured, recorded, calculated and analyzed.</p><p><b>RESULTS</b>The movement trajectories of four joints were consistent, while the elbow joint had the biggest discrete degree. The 3D activities of the shoulder and elbow were more obvious than other two joints, but the degree of flexion and extension in the knee was significantly greater than the rotation and lateral bending.</p><p><b>CONCLUSION</b>The flexibility of upper limb joint and stability of lower limb joint are the important guarantees for the Shi's cervical reduction technique, and the right knee facilitated the exerting force of upper limb by the flexion and extension activities. The 3D model built by the motion capture system would provide a new idea for manipulation teaching and further basic biomechanical research.</p>
Subject(s)
Adult , Humans , Male , Biomechanical Phenomena , Cervical Vertebrae , General Surgery , Manipulation, Orthopedic , Methods , MovementABSTRACT
Road traffic injuries have become a major social issue. With the development of technology, legislation and safety consciousness, the fatal rate of brain and chest injuries has been declined. However, as to prevent foot and ankle injuries of occupants still no effectual protective devices have been developed. In this paper, research progress on foot and ankle injuries of occupants was reviewed, which found out that most of such injuries in the frontal motor vehicle crashes occurred more easily to the drivers, which was possibly due to the special loading on their lower extremity during braking. Although there still exists a continuing debate about taxonomy of the frontal motor vehicle crashes, researchers have approached unified understanding that foot and ankle injuries are usually caused in the real-world narrow object frontal crashes. Until now, studies on foot and ankle injury and its protective mechanisms in various types of crashes are rarely conducted. A combination of the in-vitro experiment and computational modeling would be an ideal method to solve this issue.
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Objective To provide data for establishing, driving and validating the inverse dynamics model of AnyBody Modeling System, the simulated half squat parachute landing experiment was designed and relevant data were collected. Method The subject was required to jump from a 0.32 m high platform to simulate the half squat parachute landing. The kinematic parameter of lower extremity joint, the ground reaction force and the surface electromyogram (SEMG) of four main muscles in the lower extremity joint were measured simultaneously. Results The angle changes of hip, knee and ankle along with time in three anatomical planes, the ground reaction force of right foot and the trajectory of the center of pressure were collected within 1 second just before and after the subject landing. These data would be used to drive the muscleskeletal model, while the data for measuring electromyogram activity would be used to validate the model. Conclusions The experiment meets the requirement of muscleskeletal model analysis, which can be used for further study of half squat parachute landing.