Virtual Surgery Simulation Research Articles

A study of attributable variables impacting orthopedic trauma surgical training

PurposeIn medical colleges, resident training programs must provide adequate surgical experiences, making them qualified at the end of residency program. It is generally believed that it would take more time for a surgical resident to perform surgical procedures than a board-certified surgeon. There is no current benchmark with regards to operative time and surgical cases involving orthopedic surgery residents. In this study, we focused on two key aspects of surgical training variables, namely, surgical duration & C-arm shoots when the procedure is done by a faculty surgeon in comparison to done by an orthopedic resident under supervision of faculty surgeon. MethodsIt is an observational prospective study, we observed patients undergoing 1 of 5 common orthopedic trauma operations in a community teaching hospital. We recorded two variables, ‘skin to skin’ surgical duration & number of image intensifier television/C-arm shoots of faculty surgeons and orthopedic resident (postgraduate-3yr) under supervision of faculty surgeon. We calculated mean difference of two variables with or without resident & determined statistical significance, we also compared functional outcome at final follow-up. ResultsThe total number of procedure observed was 402. On observing summarized results of all surgical procedures, faculty surgeons took on an average 33 min lesser (p < 0.05) & on an average 37 lesser number of shoots (p < 0.05) than resident surgeons. The difference in surgical duration tended to increase with the greater complexity of the surgical dissection. The difference in number of C-arm shoots tended to increase with the increase in surgical duration in closed procedures. In all the five procedures there was no significant difference (p > 0.05) in functional outcome of cases performed by faulty surgeon and resident. ConclusionLittle data has been previously published regarding the impact of teaching orthopedic resident in operating room. We demonstrate that resident participation increases the procedure time for commonly performed orthopedic procedures and also the number of C-arm shoots, hence there is a need for technical training facilities outside the operating room such as in cadaveric labs, saw bone labs & virtual surgery simulation. Also the preoperative plan should be thoroughly discussed by faculty surgeon with residents.

Subjective and Objective Quantification of the Effect of Distraction on Physician's Workload and Performance During Simulated Laparoscopic Surgery.

BackgroundDistracting interference cognitive tasks place undeniable pressure on the minds of people who need high precision and attention during the tasks, such as those tasks performed during surgery; these tasks might affect current surgical procedures. We measured the effect of additional cognitive tasks on the mental load of the physician by measuring the mean change in pupil size, blink rate, and subjective assessment during surgery.Material/MethodsWe recruited 24 participants with different levels of laparoscopic surgery to perform a complete appendectomy using a standardized virtual reality laparoscopic surgery simulator. The participants then performed the cognitive task (arithmetic problem), after that they performed an appendectomy surgery task while completing the cognitive task on the simulator. All participants wore trackers to monitor pupil size and blink rate during surgery and the cognitive task. The National Aeronautics and Space Administration (NASA) Task Load Index (TLX) score also recorded performance parameters during the surgical mission.ResultsThe double-task pupil size and the blink rate were significantly increased compared to the single-task observation, and the associated increase in psychological load might have been affected by surgical performance, and the performance parameters were also statistically significant. However, for the aforementioned parameters, experienced surgeons had some differences compared with inexperienced surgeons, but these differences did not reach statistical significance.ConclusionsDistracted cognitive task stimulation in the operating room can increase the surgeon’s psychological burden while also affecting their operational skills, thereby threatening patient safety; reduced cognitive costs might be obtained by improving or managing cognitive deficits.

Construction and application of the core technology system of digital intelligent diagnostic and treatment for hepato-biliary-pancreatic diseases

Digital intelligent diagnostic and treatment technology is a novel technology which is based by combining modern medicine with digitalized and intelligent high-tech to form a multidisciplinary and multi-knowledge domain. This technology plays an important role in areas including precision diagnosis, preoperative planning and surgical navigation. Its core technologies are: (1) quality control research on high-quality CT imaging data acquisition; (2) quality control and homogenization research on three-dimensional (3D) reconstruction; (3) high-quality 3D printed physical models; (4) virtual reality 3D simulation platform; (5) molecular fluorescence imaging to define tumor boundaries; (6) non-rigid registration multi-mode image fusion surgical navigation system; (7) image feature extraction and prediction model establishment. The workflow of this system includes: First, CT data acquisition and 3D visualization of hepatobiliary and pancreatic diseases; followed by individualized vascular assessment, liver volume calculation and surgical planning using the 3D model; then virtual simulation surgery, 3D printing, virtual reality technology and molecular fluorescence imaging accordance to the required specific conditions. Preoperative radiomics are used to predict the risk of complications and long-term follow-up results. Intraoperative multi-modal fusion image navigation and its consistency are evaluated with the findings in actual surgery and preoperative planning. This technology, hopefully, will bring in novel strategies and approaches in the diagnosis and treatment of hepatobiliary and pancreatic diseases.

Condyle dislocation following mandibular reconstruction using a fibula free flap: complication cases

BackgroundCondylar dislocation can arise as a complication in patients who required mandibular and/or condylar reconstruction and were operated on with fibula free flap (FFF) using surgical guides designed using simulation surgery. Surgeons should be aware of the complications in these present cases when planning and performing reconstructions as well as predicting prognoses.Cases presentationTwo cases showed condylar dislocation in mandibular reconstruction using a FFF fixed with a reconstruction plate. Three cases showed condylar dislocation in mandibular reconstruction using a fibula free flap fixed with a mini-plate.ConclusionDespite the lack of clinical symptoms in these cases following mandibular reconstruction using an FFF, the mandibular condyle was severely displaced away from the glenoid fossa. A surgeon must have sufficient time to consider the use of a long flap with thickness similar to that of the mandible, ways to minimize span and bending, and methods of fixation. The patient, moreover, should be educated on condylar dislocation. Customized CAD/CAM-prototyped temporomandibular condyle-connected plates may be a good alternative even if virtual simulation surgery is to be performed before surgery. These considerations may help reduce the incidence of complications after mandibular reconstruction.

The application of digital medical intelligent diagnosis and treatment technology for biliary malignant tumors

With the advent of a new era of digital medicine, the emergence of a series of digital intelligent diagnosis and treatment technology has played an important role in the development of diagnosis and treatment of biliary malignant tumors. In this paper, the application of digital intelligent technology in the diagnosis and treatment of biliary malignant tumors is elaborated based on the relevant literature at home and abroad as well as the author′s practical experience in the past 15 years. This paper introduces the application of digital medical technology represented by three-dimensional visuali-zation, virtual simulation surgery, three-dimension printing technology, virtual reality, abdominal surgery navigation, medical big data and artificial intelligence-radiomics in preoperative evaluation, operation planning, and real-time intraoperative guidance, and looks forward to the new direction of intelligent technology in the diagnosis and treatment of biliary malignant tumors, so as to promote its diagnosis and treatment mode to intelligent assisted diagnosis and treatment. Key words: Biliary malignant neoplasms; Digital medicine; Fluorescence imaging; Medical big data; Artificial intelligence

The accuracy of three-dimensional rapid prototyped surgical template guided anterior segmental osteotomy.

BackgroundSurgical guiding templates provided a reliable way to transfer the simulation to the actual operation. However, there was no template designed for anterior segmental osteotomy so far. The study aimed to introduce and evaluate a set of 3D rapid prototyping surgical templates used in anterior segmental osteotomy.Material and MethodsFrom August 2015 to August 2017, 17 patients with bimaxillary protrusions were recruited and occlusal-based multi-sectional templates were applied in the surgeries. The cephalometric analysis and 3D superimposition were performed to evaluate the differences between the simulations and actual post-operative outcomes. The patients were followed-up for 12 months to evaluate the incidence rate of complications and relapse.ResultsBimaxillary protrusion was corrected in all patients with no complication. In radiographic evaluations, there was no statistically significant difference between the actual operations and the computer-aided 3D simulations (p >0.05, the mean linear and angular differences were less than 1.32mm and 1.72° consequently, and 3D superimposition difference was less than 1.4mm). The Pearson intraclass correlation coefficient reliabilities were high (0.897), and the correlations were highly significant (P< 0.001).ConclusionsThe 3D printed surgical template designed in this study can safely and accurately transfer the computer-aided 3D simulation into real practice. Key words:CAD/CAM; anterior segmental osteotomy; surgical guiding templates; bimaxillary protrusion; virtual surgery simulation.

Effectiveness of the Thoracic Pedicle Screw Placement Using the Virtual Surgical Training System: A Cadaver Study.

The virtual simulation surgery has initially exhibited its promising potentials in neurosurgery training. To evaluate effectiveness of the Virtual Surgical Training System (VSTS) on novice residents placing thoracic pedicle screws in a cadaver study. A total of 10 inexperienced residents participated in this study and were randomly assigned to 2 groups. The group using VSTS to learn thoracic pedicle screw fixation was the simulation training (ST) group and the group receiving an introductory teaching session was the control group. Ten fresh adult spine specimens including 6 males and 4 females with a mean age of 58.5 yr (range: 33-72) were collected and randomly allocated to the 2 groups. After exposing anatomic structures of thoracic spine, the bilateral pedicle screw placement of T6-T12 was performed on each cadaver specimen. The postoperative computed tomography scan was performed on each spine specimen, and experienced observers independently reviewed the placement of the pedicle screws to assess the incidence of pedicle breach. The screw penetration rates of the ST group (7.14%) was significantly lower in comparison to the control group (30%, P<.05). Statistically significant difference in acceptable rates of screws also occurred between the ST (100%) and control (92.86%) group (P<.05). In addition, the average screw penetration distance in control group (2.37 mm±0.23 mm) was significantly greater than ST group (1.23 mm±0.56 mm, P<.05). The virtual reality surgical training of thoracic pedicle screw instrumentation effectively improves surgical performance of novice residents compared to those with traditional teaching method, and can help new beginners to master the surgical technique within shortest period of time.

Virtual Functional Endoscopic Sinus Surgery Simulation with 3D-Printed Models for Mixed-Reality Nasal Endoscopy.

The surgeon's knowledge of a patient's individual anatomy is critical in skull base surgery. Trainees and experienced surgeons can benefit from surgical simulation; however, current models are expensive and impractical for widespread use. In this study, we report a next-generation mixed-reality surgical simulator. We segmented critical anatomic structures for 3-dimensional (3D) models to develop a modular teaching tool. We then developed a navigation tracking system utilizing a 3D-printed endoscope as a trackable virtual-reality (VR) controller and validated the accuracy on VR and 3D-printed skull models within 1 cm. We combined VR and augmented-reality visual cues with our 3D physical model to simulate sinus endoscopy and highlight segmented structures in real time. This report provides evidence that a mixed-reality simulator combining VR and 3D-printed models is feasible and may prove useful as an educational tool that is low cost and customizable.

A Constitutive Model of Soft Tissue Deformation for Virtual Surgical Simulation: A Literature Review

Realistic modeling of soft tissue deformation has been recognized as an essential requirement for virtual surgical simulators. As a consequence, the constitutive model is crucial for modeling soft tissue deformation. In this paper, the significance and characteristics of soft tissue deformation in virtual surgery simulation studies are introduced and analyzed its challenges. We have been focusing on investigating the constitutive relations in the soft tissue mechanical models: viscoelastic models and hyper-elastic models. Moreover, some techniques are given to determine and optimize model parameters through biomechanical experiments. Finally, based on the existing constitutive model, a novel notion for optimizing the soft tissue deformation constitutive model is proposed. The contribution of this paper is to provide theoretical guidance for the simulation of soft tissue deformation in the virtual surgery simulation system and to supply various practical suggestions for developing new constitutive models in the future.

A task and performance analysis of endoscopic submucosal dissection (ESD) surgery.

ESD is an endoscopic technique for en bloc resection of gastrointestinal lesions. ESD is a widely-used in Japan and throughout Asia, but not as prevalent in Europe or the US. The procedure is technically challenging and has higher adverse events (bleeding, perforation) compared to endoscopic mucosal resection. Inadequate training platforms and lack of established training curricula have restricted its wide acceptance in the US. Thus, we aim to develop a Virtual Endoluminal Surgery Simulator (VESS) for objective ESD training and assessment. In this work, we performed task and performance analysis of ESD surgeries. We performed a detailed colorectal ESD task analysis and identified the critical ESD steps for lesion identification, marking, injection, circumferential cutting, dissection, intraprocedural complication management, and post-procedure examination. We constructed a hierarchical task tree that elaborates the order of tasks in these steps. Furthermore, we developed quantitative ESD performance metrics. We measured task times and scores of 16 ESD surgeries performed by four different endoscopic surgeons. The average time of the marking, injection, and circumferential cutting phases are 203.4 (σ: 205.46), 83.5 (σ: 49.92), 908.4s. (σ: 584.53), respectively. Cutting the submucosal layer takes most of the time of overall ESD procedure time with an average of 1394.7s (σ: 908.43). We also performed correlation analysis (Pearson's test) among the performance scores of the tasks. There is a moderate positive correlation (R = 0.528, p = 0.0355) between marking scores and total scores, a strong positive correlation (R = 0.7879, p = 0.0003) between circumferential cutting and submucosal dissection and total scores. Similarly, we noted a strong positive correlation (R = 0.7095, p = 0.0021) between circumferential cutting and submucosal dissection and marking scores. We elaborated ESD tasks and developed quantitative performance metrics used in analysis of actual surgery performance. These ESD metrics will be used in future validation studies of our VESS simulator.

Virtual breast oncoplastic surgery simulator (VBOSS): A novel training tool in breast surgery

Virtual simulators have been employed for the teaching of breast surgery. However, there remains no virtual simulator for the training of oncoplastic breast conserving surgery. This is the first known report of virtual simulator for oncoplastic breast conserving surgery training, to the best of our knowledge.

A multi‐GPU finite element computation and hybrid collision handling process framework for brain deformation simulation

AbstractThis paper offers a fast multi‐graphics processing unit (GPU) parallel simulation framework to the problem of real‐time and nonlinear finite element computation of brain deformation. A load balancing strategy is proposed to ensure the efficient distribution of nonlinear finite element computation on multi‐GPU. A data storage structure is designed to minimize the amount of data transfer and make full use of the overlay technique of GPU to reduce the transferring latency between multi‐GPUs. We further present a fast central processing unit (CPU)–GPU parallel continuous collision detection and response method, which not only can deal with the collision between the brain and skull but also can handle the self‐collision of the brain. Our method can make full use of CPU and GPU to implement a parallel computation about deformation and collision detection. Our experimental results show that our method is able to handle a brain geometric model with high detail gyrus composed of more than 40,000 tetrahedron elements. This can facilitate the fidelity of the current virtual brain surgery simulator. We evaluate our approach qualitatively and quantitatively and compare it with related works.

High Fidelity Virtual Reality Orthognathic Surgery Simulator.

Surgical simulators are powerful tools that assist in providing advanced training for complex craniofacial surgical procedures and objective skills assessment such as the ones needed to perform Bilateral Sagittal Split Osteotomy (BSSO). One of the crucial steps in simulating BSSO is accurately cutting the mandible in a specific area of the jaw, where surgeons rely on high fidelity visual and haptic cues. In this paper, we present methods to simulate drilling and cutting of the bone using the burr and the motorized oscillating saw respectively. Our method allows low computational cost bone drilling or cutting while providing high fidelity haptic feedback that is suitable for real-time virtual surgery simulation.

A Novel Haptic Interactive Approach to Simulation of Surgery Cutting Based on Mesh and Meshless Models.

In the present work, the majority of implemented virtual surgery simulation systems have been based on either a mesh or meshless strategy with regard to soft tissue modelling. To take full advantage of the mesh and meshless models, a novel coupled soft tissue cutting model is proposed. Specifically, the reconstructed virtual soft tissue consists of two essential components. One is associated with surface mesh that is convenient for surface rendering and the other with internal meshless point elements that is used to calculate the force feedback during cutting. To combine two components in a seamless way, virtual points are introduced. During the simulation of cutting, the Bezier curve is used to characterize smooth and vivid incision on the surface mesh. At the same time, the deformation of internal soft tissue caused by cutting operation can be treated as displacements of the internal point elements. Furthermore, we discussed and proved the stability and convergence of the proposed approach theoretically. The real biomechanical tests verified the validity of the introduced model. And the simulation experiments show that the proposed approach offers high computational efficiency and good visual effect, enabling cutting of soft tissue with high stability.

Early Experience with Reduction of Unstable Pelvic Fracture Using a Computer-Aided Reduction Frame.

Purpose The optimal closed reduction technique for unstable pelvic fractures remains controversial. The purpose of this study is to verify the effectiveness and report early experiences with the reduction of unstable pelvic fractures using a computer-aided pelvic reduction frame. Methods From January 2015 to August 2016, a total of 10 patients with unilateral unstable pelvic fractures were included in this study. The surgical reduction procedure was based on the protocol of the computer-aided pelvic reduction frame that we proposed in a previous work. The quality of the reductions achieved using this system was evaluated with residual translational and rotational differences between the actual and virtual reduction positions of pelvis. The duration of the operation was recorded for quality control. Results The mean times required to set up the frame, to complete the virtual surgery simulation, and to reduce the unstable pelvic fractures were 10.3, 20.9, and 7.5 min, respectively. The maximum residual translational and rotational displacements were less than 6.5 mm and 3.71 degrees, respectively. Conclusions This computer-aided reduction frame can be a useful tool for the speedy and accurate reduction of unstable pelvic fractures. Further clinical studies should be conducted with larger patient samples to verify its safety and efficacy.

Role of Visuohaptic Surgical Training Simulator in Resident Education of Orthopedic Surgery.

We sought to assess the validity of a virtual surgical training system on lumbar pedicle screw placement for residents. Ten inexperienced residents were randomly assigned to the simulation training (ST) group (n= 5) and control group (n= 5). The ST group performed the lumbar pedicle screw placement on the virtual surgical training system, and the control group was given an introductory teaching session before the cadaver test. A total of 8 adult fresh cadavers including 5 males and 3 females were collected and randomly allocated to the 2 groups. Each group performed the bilateral L1-L5 pedicle screw instrumentation in the cadaver specimens, respectively. Accuracy was assessed by computed tomography after instrumentation. The screw penetration rates, acceptable rates, and average screw penetration distance of the 2 groups were compared using statistical analysis. The screw penetration rate of the ST group (12.5%) was significantly lower than the control group (37.5%, P < 0.05). The screw acceptable rates in ST and control groups were 100% and 85%, respectively, with statistical differences between each other (P < 0.05). There was also a statistically significant difference of the average screw penetration distance between the ST (1.37 ± 0.62 mm) group and control group (2.42 ± 0.51 mm, P < 0.05). The virtual surgery simulation with greater accuracy is superior to the traditional teaching methods in surgical training of pedicle screw placement and can be used as a promising alternative for training of neurosurgical procedures.

A Novel Nonlinear Parameter Estimation Method of Soft Tissues

The elastic parameters of soft tissues are important for medical diagnosis and virtual surgery simulation. In this study, we propose a novel nonlinear parameter estimation method for soft tissues. Firstly, an in-house data acquisition platform was used to obtain external forces and their corresponding deformation values. To provide highly precise data for estimating nonlinear parameters, the measured forces were corrected using the constructed weighted combination forecasting model based on a support vector machine (WCFM_SVM). Secondly, a tetrahedral finite element parameter estimation model was established to describe the physical characteristics of soft tissues, using the substitution parameters of Young’s modulus and Poisson’s ratio to avoid solving complicated nonlinear problems. To improve the robustness of our model and avoid poor local minima, the initial parameters solved by a linear finite element model were introduced into the parameter estimation model. Finally, a self-adapting Levenberg–Marquardt (LM) algorithm was presented, which is capable of adaptively adjusting iterative parameters to solve the established parameter estimation model. The maximum absolute error of our WCFM_SVM model was less than 0.03 Newton, resulting in more accurate forces in comparison with other correction models tested. The maximum absolute error between the calculated and measured nodal displacements was less than 1.5 mm, demonstrating that our nonlinear parameters are precise.

Combined endeavor of Neutrosophic Set and Chan-Vese model to extract accurate liver image from CT scan

Many different diseases can occur in the liver, including infections such as hepatitis, cirrhosis, cancer and over effect of medication or toxins. The foremost stage for computer-aided diagnosis of liver is the identification of liver region. Liver segmentation algorithms extract liver image from scan images which helps in virtual surgery simulation, speedup the diagnosis, accurate investigation and surgery planning. The existing liver segmentation algorithms try to extort exact liver image from abdominal Computed Tomography (CT) scan images. It is an open problem because of ambiguous boundaries, large variation in intensity distribution, variability of liver geometry from patient to patient and presence of noise. A novel approach is proposed to meet challenges in extracting the exact liver image from abdominal CT scan images. The proposed approach consists of three phases: (1) Pre-processing (2) CT scan image transformation to Neutrosophic Set (NS) and (3) Post-processing. In pre-processing, the noise is removed by median filter. The “new structure” is designed to transform a CT scan image into neutrosophic domain which is expressed using three membership subset: True subset (T), False subset (F) and Indeterminacy subset (I). This transform approximately extracts the liver image structure. In post processing phase, morphological operation is performed on indeterminacy subset (I) and apply Chan-Vese (C-V) model with detection of initial contour within liver without user intervention. This resulted in liver boundary identification with high accuracy. Experiments show that, the proposed method is effective, robust and comparable with existing algorithm for liver segmentation of CT scan images.

Can a virtual reality surgical simulation training provide a self-driven and mentor-free skills learning? Investigation of the practical influence of the performance metrics from the virtual reality robotic surgery simulator on the skill learning and associated cognitive workloads.

While it is often claimed that virtual reality (VR) training system can offer self-directed and mentor-free skill learning using the system's performance metrics (PM), no studies have yet provided evidence-based confirmation. This experimental study investigated what extent to which trainees achieved their self-learning with a current VR simulator and whether additional mentoring improved skill learning, skill transfer and cognitive workloads in robotic surgery simulation training. Thirty-two surgical trainees were randomly assigned to either the Control-Group (CG) or Experiment-Group (EG). While the CG participants reviewed the PM at their discretion, the EG participants had explanations about PM and instructions on how to improve scores. Each subject completed a 5-week training using four simulation tasks. Pre- and post-training data were collected using both a simulator and robot. Peri-training data were collected after each session. Skill learning, time spent on PM (TPM), and cognitive workloads were compared between groups. After the simulation training, CG showed substantially lower simulation task scores (82.9±6.0) compared with EG (93.2±4.8). Both groups demonstrated improved physical model tasks performance with the actual robot, but the EG had a greater improvement in two tasks. The EG exhibited lower global mental workload/distress, higher engagement, and a better understanding regarding using PM to improve performance. The EG's TPM was initially long but substantially shortened as the group became familiar with PM. Our study demonstrated that the current VR simulator offered limited self-skill learning and additional mentoring still played an important role in improving the robotic surgery simulation training.

Simulation-guided navigation for vector control in pediatric mandibular distraction osteogenesis

AimNavigation technology has given surgeons the capacity to know precisely where their instruments are during surgery, and simulation-guided navigation is a surgical method which is based on the use of navigation technology linked to 3D virtual surgery simulation. The aim of the present study was to evaluate the absolute accuracy of simulation-guided navigation as an aid to reproduce the planned position of the distraction device vector in pediatric mandibular distraction osteogenesis. Materials and methodsWe retrospectively evaluated seven patients affected by unilateral (3 pts.) or bilateral (4 pts.) mandibular hypoplasia and treated with this method between 2012 and 2014 at the Maxillofacial Surgery Unit of the University of Bologna, Italy. All patients were enrolled for mandibular distraction using internal unidirectional devices (11 distraction devices implanted overall). Patients were studied through a complete three-dimensional workflow, which led to obtaining a virtual reconstruction of the facial bones and the simulation of the distraction device positioning using a specific experimental software. The surgical planning was loaded on the navigation system and the distraction device was placed following the virtual plan, which is displayed on the navigation system as a guide and tracked with the navigation instruments. ResultsWe analyzed the outcome comparing the recorded three-dimensional coordinates of the achieved distractor position and the three-dimensional coordinates of the planned distractor position. Among the eleven placed distractors, we found a mean angular error of 3.74° ± 3.30° on the axial axis (yaw) and of 6.27° ± 5.32° on the sagittal axis (pitch), while median angular errors are 3.72° on the axial axis (yaw) and 4.08° on the sagittal axis (pitch). ConclusionOur preliminary experience seems to support that simulation-guided navigation for vector control in mandibular distraction osteogenesis could be a useful procedure for reproducing the virtually planned outcome. Nevertheless, our results cannot be considered completely satisfactory. There is a lot of room to improve accuracy and errors seem to depend mainly on the soft tissues interference during distractor placement.