We developed a rehabilitation system by using the virtual reality technique and the Kinect in this paper. The system combines rehabilitation training with HMI and serious game organically, and provides a game and motion database to meet different patients' demands. Extended interface of game database is provided in two ways: personalized games can be developed by Virtools and Flash games which are suitable for patients' rehabilitation can be download from the Internet directly. In addition, the system provides patients with flexible interaction and easy control mode, and also presents real time data recording. An objective and subjective evaluation method is proposed to review the effectiveness of the rehabilitation training. According to the results of short questionnaires and the evaluation results of patients' rehabilitation training, the system compared with traditional rehabilitation can record and analyze the training data, which is useful to make rehabilitation plans. More entertainment and lower cost will increase patients' motivation, which helps to increase the rehabilitation effectiveness.
Mass point-spring model is one of the commonly used models in virtual surgery. However, its model parameters have no clear physical meaning, and it is hard to set the parameter conveniently. We, therefore, proposed a method based on genetic algorithm to determine the mass-spring model parameters. Computer-aided tomography (CAT) data were used to determine the mass value of the particle, and stiffness and damping coefficient were obtained by genetic algorithm. We used the difference between the reference deformation and virtual deformation as the fitness function to get the approximate optimal solution of the model parameters. Experimental results showed that this method could obtain an approximate optimal solution of spring parameters with lower cost, and could accurately reproduce the effect of the actual deformation model as well.
With the wide application of virtual reality technology and the rapid popularization of virtual reality devices, the problem of brain fatigue caused by prolonged use has attracted wide attention. Sixteen healthy subjects were selected in this study. And electroencephalogram (EEG) signals were acquired synchronously while the subjects watch videos in similar types presented by traditional displayer and virtual reality separately. Two questionnaires were conducted by all subjects to evaluate the state of fatigue before and after the experiment. The mutual correlation method was selected to construct the mutual correlation brain network of EEG signals before and after watching videos in two modes. We also calculated the mutual correlation coefficient matrix and the mutual correlation binary matrix and compared the average of degree, clustering coefficient, path length, global efficiency and small world attribute during two experiments. The results showed that the subjects were easier to get fatigue by watching virtual reality video than watching video presented by traditional displayer in a certain period of time. By comparing the characteristic parameters of brain network before and after watching videos, it was found that the average degree value, the average clustering coefficient, the average global efficiency and the small world attribute decreases while the average path length value increased significantly. In addition, compared to traditional plane video, the characteristic parameters of brain network changed more greatly after watching the virtual reality video with a significant difference (P < 0.05). This study can provide theoretical basis and experimental reference for analyzing and evaluating brain fatigue induced by virtual reality visual experience.
ObjectiveTo explore the application value of multidisciplinary collaborative team (MDT) model in retroperitoneal tumors involving large vessels.MethodsThree cases of retroperitoneal tumors involving great vessels admitted to Xiang’an Hospital of Xiamen University in 2019 were retrospectively analyzed. With the support of 3D visual reconstruction and virtual reality (VR) technology, we performed MDT discussion and three cases received treatment of surgery, intervention, and targeted therapy.ResultsCase 1 was discussed by MDT and concluded that, based on CT examination, 3D reconstruction, and VR virtual image results, the tumor on the right side was determined to be completely resectable. The left tumor was judged to be unresectable, and the proposed treatment plan was right metastatic tumor resection + left metastatic tumor radiofrequency ablation. After surgery case 1 had been followed up for 6 months. The symptoms of diarrhea were significantly improved. CT reexamination showed that liver lesions and left retroperitoneal lesions were the same size and the condition was stable. After discussion by MDT, radiofrequency ablation around the tumor was proposed for case 2. This case was followed up for 3 months after surgery, and CT reexamination showed no new lesion in retroperitoneum. After MDT discussion, we concluded that arteriovenous fistula of case 3 had no indications for surgery, and proposed interventional combined with targeted therapy. After treatment, the tumor was found to be smaller after reexamination in 8 months than before treatment, and the efficacy was evaluated as partial remission. The follow-up was continued.ConclusionThe future development trend of retroperitoneal tumor therapy involving great vessels is to evaluate each patient’s condition under the MDT mode by using 3D visual reconstruction and VR technology, and to formulate the individualized treatment plan of operation combined with other treatments.
ObjectiveTo explore the feasibility and effectiveness of the modified transtrochanteric curved varus osteotomy in the treatment of osteonecrosis of the femoral head (ONFH), clarify the key points of the operation, and then explore the effectiveness of modified transtrochanteric curved varus osteotomy in the treatment of ONFH assisted by virtual reality (VR) technology. MethodsA 70-year-old adult female cadaver without formaldehyde fixation was taken. It was confirmed by anatomical study and simulated operation that the modified transtrochanteric curved varus osteotomy was suitable for type C1 (patients with involvement of the lateral column of the femoral head but partial integrity) classified by the Japanese Osteonecrosis Investigation Committee (JIC). Between October 2018 and August 2020, 11 patients (17 hips) with ONFH who met the selection criteria were treated with modified transtrochanteric curved varus osteotomy. VR technology was used to simulate varus osteotomy before operation to predict the angle of valgus of lower limbs and pronation of femoral head. Osteotomy, valgus, and pronation were performed according to the results of preoperative planning. After operation, X-ray films were used to evaluate the changes of varus and neck-shaft angle after VR assisted surgery, and Harris score was used to evaluate the hip function. ResultsThe anteroposterior pelvic X-ray film was rechecked at 2 days after operation, of which 3 hips were consistent with the planned varus angle of VR preoperative planning, and the error value of varus angle of the remaining 14 hips was 1°-4°. The difference between VR preoperative planning and 2 days after operation was 6°-16°. All 11 patients were followed up 11-28 months, with an average of 19.2 months. All incisions healed by first intension. During the follow-up, 1 case (1 hip) developed greater trochanter fracture at 2 months after operation and was treated with open reduction and plate and screw internal fixation; 1 case (1 hip) had delayed healing at osteotomy at 4 months after operation and healed at 3 months after local injection of platelet rich plasma and oral supplementation of kidney blood-strengthening soup. At last follow-up, 17 hip osteotomies healed. The Harris score was 84.0±5.6, which was significantly higher than that before operation (57.2±5.5) (t=–14.107, P=0.000); hip function was excellent in 2 hips, good in 13 hips, and fair in 2 hips. ConclusionThe modified transtrochanteric curved varus osteotomy for the treatment of ONFH is theoretically feasible, and the short-term effectiveness of this operation combined with VR technology is satisfactory.
There are two modes to display panoramic movies in virtual reality (VR) environment: non-stereoscopic mode (2D) and stereoscopic mode (3D). It has not been fully studied whether there are differences in the activation effect between these two continuous display modes on emotional arousal and what characteristics of the related neural activity are. In this paper, we designed a cognitive psychology experiment in order to compare the effects of VR-2D and VR-3D on emotional arousal by analyzing synchronously collected scalp electroencephalogram signals. We used support vector machine (SVM) to verify the neurophysiological differences between the two modes in VR environment. The results showed that compared with VR-2D films, VR-3D films evoked significantly higher electroencephalogram (EEG) power (mainly reflected in α and β activities). The significantly improved β wave power in VR-3D mode showed that 3D vision brought more intense cortical activity, which might lead to higher arousal. At the same time, the more intense α activity in the occipital region of the brain also suggested that VR-3D films might cause higher visual fatigue. By the means of neurocinematics, this paper demonstrates that EEG activity can well reflect the effects of different vision modes on the characteristics of the viewers’ neural activities. The current study provides theoretical support not only for the future exploration of the image language under the VR perspective, but for future VR film shooting methods and human emotion research.
Objective To investigate the effect of lower limb rehabilitation robot combined with virtual reality training on walking ability after anterior cruciate ligament reconstruction (ACLR). Methods Patients after ACLR treated in the Rehabilitation Medical Center of the Second Hospital of Jiaxing between May 2019 and July 2021 were selected. The patients were randomly divided into two groups. The patients with conventional ACLR rehabilitation training + lower limb rehabilitation robot combined with virtual reality training were used as the treatment group, and only the patients with conventional ACLR rehabilitation training were used as the control group. The rehabilitation training lasted for 8 weeks. After 4 and 8 weeks of treatment, the two groups were evaluated by Lysholm knee score scale (LKSS), Holden walking score and Gait watch gait analysis. Results A total of 40 patients were included, with 20 patients in each group. There was no significant difference between the two groups in LKSS score, Holden walking score and Gait watch gait analysis dynamic data at 4 weeks of treatment (P>0.05). After 8 weeks of treatment, the LKSS score [(77.74±5.53) vs. (69.53±5.26) points], Holden walking score [(4.79±0.34) vs. (4.45±0.39) points] and Gait watch gait analysis dynamic data [step size: (78.35±2.43) vs. (73.64±3.35) cm, step frequency: (115.10±4.49) vs. (107.71±5.14) step/min, step speed: (108.63±8.55) vs. (96.78±8.47) cm/s] of the treatment group were better than those of the control group (P<0.05), The above indexes of the two groups were improved compared with those at 4 weeks of treatment (P<0.05). Conclusion Lower limb rehabilitation robot combined with virtual reality training can effectively improve walking ability after ACLR.