Dance/movement therapy for improving balance ability and bone mineral density in long-term patients with schizophrenia: a randomized controlled trial.

Fractures are common accidents for long-term hospitalized patients with schizophrenia (SZ) in psychiatric hospitals, and once they occur, patients usually endure the pain of fractures for a long time. Accumulating evidence has supported the implementation of dance/movement therapy (DMT) as a promising intervention for patients with SZ. However, no research has been conducted to investigate its role in balance ability in SZ. This study was designed to investigate the efficacy of a 12-week DMT intervention in bone mineral density and balance ability in patients with SZ using a randomized, controlled trial design. A total of 58 veterans with SZ were randomly assigned to the DMT intervention group (n = 29) and the treatment-as-usual (TAU) group (n = 29). Bone mineral density (BMD) and balance ability were measured in both groups at two measurement points (at baseline and at the end of Week 12). We found that patients in the DMT intervention group had significant improvements in BMD and balance ability compared with the TAU group by using repeated measures analysis of variance. Treatment with DMT demonstrated a significant improvement in BMD from baseline to week 12 (0.03, 95% CI: 0.01-0.05). For the Berg total score and static and dynamic balance, the mean changes in the DMT group were 7.3 (95% CI: 5.6-9.0), 4.0 (95% CI: 0.9-7.1), and 3.7 (95% CI: 2.6-4.8), respectively. Regression analysis showed that baseline BMD was a significant predictor of improvement in BMD from baseline to week 12 in the DMT group (ß = 0.58, p < 0.001). Our results suggest for the first time that DMT intervention may be effective in beneficially regulating BMD and balance ability in SZ patients.

From Skin Mechanics to Tactile Neural Coding: Predicting Afferent Neural Dynamics During Active Touch and Perception.

First order cutaneous neurons allow object recognition, texture discrimination, and sensorimotor feedback. Their function is well-investigated under passive stimulation while their role during active touch or sensorimotor control is understudied. To understand how human perception and sensorimotor controlling strategy depend on cutaneous neural signals under active tactile exploration, the finite element (FE) hand and Izhikevich neural dynamic model were combined to predict the cutaneous neural dynamics and the resulting perception during a discrimination test. Using in-vivo microneurography generated single afferent recordings, 75% of the data was applied for the model optimization and another 25% was used for validation. By using this integrated numerical model, the predicted tactile neural signals of the single afferent fibers agreed well with the microneurography test results, achieving the out-of-sample values of 0.94 and 0.82 for slowly adapting type I (SAI) and fast adapting type I unit (FAI) respectively. Similar discriminating capability with the human subject was achieved based on this computational model. Comparable performance with the published numerical model on predicting the cutaneous neural response under passive stimuli was also presented, ensuring the potential applicability of this multi-level numerical model in studying the human tactile sensing mechanisms during active touch. The predicted population-level 1st order afferent neural signals under active touch suggest that different coding strategies might be applied to the afferent neural signals elicited from different cutaneous neurons simultaneously.

In vitro and in vivo evaluation of a novel lidocaine-loaded cubosomal gel for prolonged local anesthesia.

Marketed lidocaine dosage forms (such as ointment, gels, and injections) used to manage acute and chronic pain showed a short duration of action (<2 h). In this study, a lidocaine-loaded cubosomal gel was prepared to sustain the release of lidocaine to prolong the local anesthetic effect (high drug retention in the skin). Lidocaine-loaded cubosomal gels were prepared by melt emulsification and sonication using Pluronic F127 and DL-α-monoolein (at different levels). The cubosomal gels were characterized by morphology, size, zeta potential, entrapment efficacy, assay, viscosity, pH, and texture profiles. Ex vivo lidocaine permeation and retention studies were performed using Sprague-Dawley rat skin. Transmission electron microscopy images confirmed the bi-continuous liquid crystalline phase with a honeycomb cubosome structure. The cubosomal particle size (103-227 nm), viscosity (13,524-15,627cp), and entrapment efficacy (78.4-94.7%) increase with the level of monoolein. The ex-vivo permeation study showed a biphasic release pattern, with lidocaine cleared from ointment within 4 h (97.9% cumulative release), while cubosomal gels showed sustained release up to 24 h (53.33-98.86% cumulative release). A skin retention study demonstrated that cubosomes can increase (up to 28-fold) the lidocaine content in the skin (4.56 mg) compared to ointment (0.19 mg). A rabbit skin irritation study showed no sign of irritation after the application of cubosomal gel. In the radiant heat tail-flick study, the local anesthetic effect of lidocaine from the cubosomal gel was sustained for up to 16 h with 1.43-fold higher efficacy than marketed ointment. In conclusion, the study demonstrated the potential of cubosomal nanoparticle-laden gel to sustain the release of lidocaine for prolonging local anesthetic effects for pain management.

Biomechanical Analysis of the Effect of the Finger Extensor Mechanism on Hand Grasping Performance.

Quantifying the effect of routing and topology of the inter-connected finger extensor mechanism on hand grasping performances is a long-standing research problem for the better clinical diagnosis, surgical planning and biomimetic hand development. However, it is technically demanding to measure the hand performance parameters such as the contact forces and contact area during hand manipulation. It is also difficult to replicate human hand performance through the physical hand model due to its sophisticated musculotendinous structure. In this study, an experimental validated subject-specific finite element (FE) human hand model was used for the first time to quantify the influence of different tendon topologies and material properties on hand grasping quality. It is found that the grasping quality is reduced by 15.94% and 8.54% if there are no extensor hood and lateral band respectively, and the former plays a more important role in transmitting forces and maintaining grasping qualities than the latter. Excluding extensor hood in the topology causes more reductions in hand contact pressure and contact area than omitting lateral band. 7.5% of the grasping quality is lost due to a softened tendon with half of its original Young's Modulus. Hardened extensor tendon does increase the grasping quality, but the enhancing effect tends to level off once the tendon Young's Modulus is increased by more than 50%. These results prove that the lateral band and extensor hood are critical components for maintaining grasping quality. The dexterity and grasping quality of robotic and prosthetic hands could be improved by integrating these two components. There is also no need to use very stiff tendon material as it won't help to effectively enhance the grasping quality.

Biomechanical analysis of the effect of finger joint configuration on hand grasping performance: rigid vs flexible.

Human finger joints are conventionally simplified as rigid joints in robotic hand design and biomechanical hand modelling, due to their anatomic and morphologic complexity. However, our understanding of the effect of the finger joint configuration on the resulting hand performance is still primitive. In this study, we systematically investigate the grasping performance of the hands with the conventional rigid joints and the biomechanical flexible joints based on a computational human hand model. The measured muscle electromyography (EMG) and hand kinematic data during grasping are used as inputs for the grasping simulations. The results show that the rigid joint configuration currently used in most robotic hands leads to large reductions in hand contact force, contact pressure and contact area, compared to the flexible joint configuration. The grasping quality could be reduced up to 40% and 36% by the rigid joint configuration in terms of algebraic properties of grasping matrix and finger force limit respectively. Further investigation reveals that these reductions are caused by the weak rotational stiffness of the rigid joint configuration. This study implies that robotic/prosthetic hand performance could be improved by exploiting flexible finger joint design. Hand contact parameters and grasping performance may be underestimated by the rigid joint simplification in human hand modelling.

Subject-Specific Finite Element Modelling of the Human Hand Complex: Muscle-Driven Simulations and Experimental Validation.

This paper aims to develop and validate a subject-specific framework for modelling the human hand. This was achieved by combining medical image-based finite element modelling, individualized muscle force and kinematic measurements. Firstly, a subject-specific human hand finite element (FE) model was developed. The geometries of the phalanges, carpal bones, wrist bones, ligaments, tendons, subcutaneous tissue and skin were all included. The material properties were derived from in-vivo and in-vitro experiment results available in the literature. The boundary and loading conditions were defined based on the kinematic data and muscle forces of a specific subject captured from the in-vivo grasping tests. The predicted contact pressure and contact area were in good agreement with the in-vivo test results of the same subject, with the relative errors for the contact pressures all being below 20%. Finally, sensitivity analysis was performed to investigate the effects of important modelling parameters on the predictions. The results showed that contact pressure and area were sensitive to the material properties and muscle forces. This FE human hand model can be used to make a detailed and quantitative evaluation into biomechanical and neurophysiological aspects of human hand contact during daily perception and manipulation. The findings can be applied to the design of the bionic hands or neuro-prosthetics in the future.

Biomechanical comparison of screw-based zones of a spatial subchondral support plate for proximal humerus fractures.

Stabilisation of proximal humerus fractures remains a surgical challenge. Spatial subchondral support (S3) plate promises to overcome common complications associated with conventional proximal humerus plates. This study compared the biomechanical performance of S3 plate with a fixed-angle hybrid blade (Equinoxe Fx) plate and a conventional fixed-angle locking plate (PHILOS). The effects of removal of different S3 plate screws on the humeral stability were also investigated. A total of 20 synthetic left humeri were osteotomised transversely at the surgical neck to simulate a two-part fracture and were each treated with an S3 plate. Head screws were divided into three zones based on their distance from the fracture site. Specimens were divided into four equal groups where one group acted as a control with all screws and three groups had one of the screw zones missing. With humeral head fixed, humeral shaft was first displaced 5 mm in extension, flexion, valgus and varus direction (elastic testing) and then until 30 mm varus displacement (plastic testing). Load-displacement data were recorded to determine construct stiffness in elastic tests and assess specimens' varus stability under plastic testing. Removal of the screw nearest to the fracture site led to a 20.71% drop in mean elastic varus bending stiffness. Removal of the two inferomedial screw above it resulted in a larger drop. The proximal screw pair had the largest contribution to extension and flexion bending stiffness. Varus stiffness of S3 plate constructs was higher than PHILOS and Fx plate constructs. Stability of humeri treated with S3 plate depends on screws' number, orientation and location. Varus stiffness of S3 plate construct (10.54 N/mm) was higher than that of PHILOS (6.61 N/mm) and Fx (7.59 N/mm) plate constructs. We attribute this to S3 plates' thicker cross section, the 135° inclination of its screws with respect to the humeral shaft and the availability of pegs for subchondral support.

Parametric Design Optimisation of Proximal Humerus Plates Based on Finite Element Method.

Optimal treatment of proximal humerus fractures remains controversial. Locking plates offer theoretical advantages but are associated with complications in the clinic. This study aimed to perform parametric design optimisation of proximal humerus plates to enhance their mechanical performance. A finite element (FE) model was developed that simulated a two-part proximal humerus fracture that had been treated with a Spatial Subchondral Support (S3) plate and subjected to varus bending. The FE model was validated against in vitro biomechanical test results. The predicted load required to apply 5 mm cantilever varus bending was only 0.728% lower. The FE model was then used to conduct a parametric optimisation study to determine the orientations of inferomedial plate screws that would yield minimum fracture gap change (i.e. optimal stability). The feasible design space was automatically identified by imposing clinically relevant constraints, and the creation process of each FE model for the design optimisation was automated. Consequently, 538 FE models were generated, from which the obtained optimal model had 4.686% lower fracture gap change (0.156 mm) than that of the manufacturer's standard plate. Whereas its screws were oriented towards the inferomedial region and within the range of neck-shaft angle of a healthy subject. The methodology presented in this study promises future applications in patient-specific design optimisation of implants for other regions of the human body.

Biomechanical comparison of screw-based zoning of PHILOS and Fx proximal humerus plates.

BACKGROUND: Treatment of proximal humerus fractures with locking plates is associated with complications. We aimed to compare the biomechanical effects of removing screws and blade of a fixed angle locking plate and hybrid blade plate, on a two-part fracture model. METHODS: Forty-five synthetic humeri were divided into nine groups where four were implanted with a hybrid blade plate and the remaining with locking plate, to treat a two-part surgical neck fracture. Plates' head screws and blades were divided into zones based on their distance from fracture site. Two groups acted as a control for each plate and the remaining seven had either a vacant zone or blade swapped with screws. For elastic cantilever bending, humeral head was fixed and the shaft was displaced 5 mm in extension, flexion, valgus and varus direction. Specimens were further loaded in varus direction to investigate their plastic behaviour. RESULTS: In both plates, removal of inferomedial screws or blade led to a significantly larger drop in varus construct stiffness than other zones. In blade plate, insertion of screws in place of blade significantly increased the mean extension, flexion valgus and varus bending stiffness (24.458%/16.623%/19.493%/14.137%). In locking plate, removal of screw zones proximal to the inferomedial screws reduced extension and flexion bending stiffness by 26-33%. CONCLUSIONS: Although medial support improved varus stability, two inferomedial screws were more effective than blade. Proximal screws are important for extension and flexion. Mechanical consequences of screw removal should be considered when deciding the number and choice of screws and blade in clinic.

Hybrid blade and locking plate fixation for proximal humerus fractures: a comparative biomechanical analysis.

BACKGROUND: Open reduction and internal fixation of proximal humerus fractures can be difficult to achieve adequate, complication free results due to osteopenia of the proximal humerus and unstable fracture patterns. This study aimed to compare the biomechanical properties of a novel hybrid fixed angle blade plate (Fx plate) with an established fixed angle locking plate (PHILOS plate). METHODS: A two-part fracture was simulated in synthetic composite humeri by creating a transverse osteotomy and 10 mm fracture gap at the surgical neck. After treating the fractures with either an Fx plate or a PHILOS plate, humeral head was fixed and the shaft was displaced in a cantilever fashion. For elastic tests, loading was along the frontal and sagittal plane to achieve varus/valgus and extension/flexion, respectively. In plastic tests, loading was in a varus direction to determine the constructs' resistance to varus collapse. RESULTS: In elastic tests, both construct types had higher peak load and stiffness in extension/flexion than varus/valgus. Fx plate constructs were significantly stiffer than PHILOS constructs in varus/valgus (mean: 7.590/6.900 vs. 6.609/6.091 N/mm; p < 0.001 for both) but significantly less stiff in extension/flexion (8.770/9.541 vs. 9.533/9.997 N/mm; p < 0.001 for extension, p < 0.05 for flexion). In varus plastic tests, significantly higher peak loads were reported for Fx plate than PHILOS (134.391 vs. 115.531 N; p < 0.001). CONCLUSIONS: In this fracture gap model, humeri implanted with a novel Fx plate provided higher varus/valgus stiffness but lower extension/flexion stiffness than a more traditional proximal humeral locking plate design (PHILOS).

Finite element models of the human shoulder complex: a review of their clinical implications and modelling techniques.

The human shoulder is a complicated musculoskeletal structure and is a perfect compromise between mobility and stability. The objective of this paper is to provide a thorough review of previous finite element (FE) studies in biomechanics of the human shoulder complex. Those FE studies to investigate shoulder biomechanics have been reviewed according to the physiological and clinical problems addressed: glenohumeral joint stability, rotator cuff tears, joint capsular and labral defects and shoulder arthroplasty. The major findings, limitations, potential clinical applications and modelling techniques of those FE studies are critically discussed. The main challenges faced in order to accurately represent the realistic physiological functions of the shoulder mechanism in FE simulations involve (1) subject-specific representation of the anisotropic nonhomogeneous material properties of the shoulder tissues in both healthy and pathological conditions; (2) definition of boundary and loading conditions based on individualised physiological data; (3) more comprehensive modelling describing the whole shoulder complex including appropriate three-dimensional (3D) representation of all major shoulder hard tissues and soft tissues and their delicate interactions; (4) rigorous in vivo experimental validation of FE simulation results. Fully validated shoulder FE models would greatly enhance our understanding of the aetiology of shoulder disorders, and hence facilitate the development of more efficient clinical diagnoses, non-surgical and surgical treatments, as well as shoulder orthotics and prosthetics. © 2016 The Authors. International Journal for Numerical Methods in Biomedical Engineering published by John Wiley & Sons Ltd.

Optimization of the position of the acetabulum in a ganz periacetabular osteotomy by finite element analysis.

Periacetabular osteotomy (PAO) is a surgical procedure to correct acetabular orientation in developmental dysplasia of the hip (DDH). It changes the position of the acetabulum to increase femoral head coverage and distribute the contact pressure over the cartilage surface. The success of PAO depends significantly on the surgeon's experience. Using computed tomography data from patients with DDH, we developed a 3D finite element (FE) model to investigate the optimal position of the acetabulum following PAO. A virtual PAO was performed with the acetabulum rotated in increments from the original center edge (CE) angle. Contact area, contact pressure, and Von Mises stress in the femoral and pelvic cartilage were analyzed. Five dysplastic hips from four patients were modeled. Contact area, contact pressure, and Von Mises stress in the cartilage all varied according to the change of CE angle through virtual PAO. An optimal position could be achieved for the acetabulum that maximizes the contact area while minimizing the contact pressure and von Mises stress in the pelvic and femoral cartilage. The optimal position of the acetabulum was patient dependent and did not always correspond to what would be considered a "normal" CE angle. We demonstrated for the first time the interrelation of correction angle, contact area, and contact pressure between the pelvic and femoral cartilage in PAO surgery.

Fracture simulation of restored teeth using a continuum damage mechanics failure model.

OBJECTIVE: The aim of this paper is to validate the use of a finite-element (FE) based continuum damage mechanics (CDM) failure model to simulate the debonding and fracture of restored teeth. MATERIALS AND METHODS: Fracture testing of plastic model teeth, with or without a standard Class-II MOD (mesial-occusal-distal) restoration, was carried out to investigate their fracture behavior. In parallel, 2D FE models of the teeth are constructed and analyzed using the commercial FE software ABAQUS. A CDM failure model, implemented into ABAQUS via the user element subroutine (UEL), is used to simulate the debonding and/or final fracture of the model teeth under a compressive load. The material parameters needed for the CDM model to simulate fracture are obtained through separate mechanical tests. The predicted results are then compared with the experimental data of the fracture tests to validate the failure model. RESULTS: The failure processes of the intact and restored model teeth are successfully reproduced by the simulation. However, the fracture parameters obtained from testing small specimens need to be adjusted to account for the size effect. The results indicate that the CDM model is a viable model for the prediction of debonding and fracture in dental restorations.