Novel 3-dimensional virtual hepatectomy simulation combined with real-time deformation

Sonographically-guided Parasacrum Infrapiriformis Drainage of Deep Pelvic Abscesses: An Anatomical Safety Study Using SYNAPSE VINCENT

Objectives

Deep pelvic abscesses are surrounded by the pelvic bones, bladder, gynecological organs, intestinal tract, and nerve and vascular systems, and are approached by various routes for drainage. The transgluteal approach is often performed under computed tomography guidance; however, if ultrasonography can be used to confirm the approach, it is considered more effective because it reduces radiation exposure and allows for real-time puncture under sonographic and fluoroscopic guidance.

Methods

This retrospective study was conducted at Tobata Kyoritsu Hospital (Fukuoka, Japan) between April 1, 2021, and December 31, 2022. Sonographically guided transgluteal drainage with fluoroscopy was performed in five consecutive cases of deep pelvic abscesses using a 3D image analysis system (SYNAPSE VINCENT) to study the anatomy for safe puncture.

Results

Three patients had postoperative abscesses from colorectal cancer, one caused by perforation of the appendicitis, and one caused by sigmoid diverticulitis. The average drainage duration was 11 days (SD = 6.7). No complications, such as bleeding or nerve damage, were observed.

Conclusions

We constructed a 3D image of the puncture route of the trans greater sciatic foramen using SYNAPSE VINCENT to objectively comprehend the anatomy and puncture route. The ideal transgluteal approach is to insert the catheter as close to the sacrum as possible at the level of the infrapiriformis. The parasacrum infrapiriformis approach can be performed safely and easily using ultrasound guidance and fluoroscopy.

Assessment and evaluation of online education and virtual simulation technology in dental education: a cross-sectional survey

BACKGROUND

The global outbreak of coronavirus disease (COVID-19) has led medical universities in China to conduct online teaching. This study aimed to assess the effectiveness of a blended learning approach that combines online teaching and virtual reality technology in dental education and to evaluate the acceptance of the blended learning approach among dental teachers and students.

METHODS

The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) checklist was followed in this study. A total of 157 students' perspectives on online and virtual reality technology education and 54 teachers' opinions on online teaching were collected via questionnaires. Additionally, 101 students in the 2015-year group received the traditional teaching method (TT group), while 97 students in the 2017-year group received blended learning combining online teaching and virtual reality technology (BL group). The graduation examination results of students in the two groups were compared.

RESULTS

The questionnaire results showed that most students were satisfied with the online course and the virtual simulation platform teaching, while teachers held conservative and neutral attitudes toward online teaching. Although the theoretical score of the BL group on the final exam was greater than that of the TT group, there was no significant difference between the two groups (P = 0.805). The skill operation score of the BL group on the final exam was significantly lower than that of the TT group (P = 0.004). The overall score of the BL group was lower than that of the TT group (P = 0.018), but the difference was not statistically significant (P = 0.112).

CONCLUSIONS

The blended learning approach combining online teaching and virtual reality technology plays a positive role in students' learning and is useful and effective in dental education.

Application of computer-assisted surgery in pediatric mediastinal tumor surgery

BACKGROUND

Computer-assisted Surgery system (CAS) is an effective medical imaging simulation tool, which is widely used in preoperative planning of surgery. The objective of this study is to investigate the clinical application of CAS in pediatric mediastinal tumor resection.

METHODS

This retrospective study investigated 74 children who underwent mediastinal tumor resection between June 2008 and June 2022 at the pediatric surgical center of the Affiliated Hospital of Qingdao University and Qingdao Women and Children's Hospital. Preoperative chest computed tomography imaging was performed on all children. A total of 44 children (the CAS-assisted group) underwent clinical image 3D reconstruction and preoperative simulation using Hisense CAS. The control group consisted of 30 children who underwent a conventional procedure without CAS. The demographic, preoperative, and complication data were analyzed and compared between the two groups. t-test, Mann-Whitney U test, X² test, or Fisher's exact test were used accordingly in this study during analysis.

RESULTS

The median operative duration was 119.00 min in the CAS-assisted group and 140.50 min in the control group. The median intraoperative blood loss of the CAS-assisted group and the control group was 14.00 and 31.00 ml respectively. Relative to the control groups, the CAS-assisted group experienced shorter operative duration time (p = 0.041), and less intraoperative blood loss (p < 0.001). The difference in postoperative drain indwelling between the CAS-assisted group (median:4.00 days) and the control group (median:7.00 days) reached a statistical significance (p = 0.001). And the duration of hospitalization after the operation for the CAS-assisted group (median:7.00 days) was shorter than that for the control group (median:9.00 days) (p = 0.001). No significant difference could be found in the rate of blood transfusion (p = 0.258) and the incidence of postoperative complications (p = 0.719) between the two groups.

CONCLUSION

Hisense CAS could effectively assist surgeons to clearly determine the anatomical site of tumors and provide accurate preoperative simulation for surgeons, so as to assist surgeons to specify effective surgical plans for patients.

Effectiveness of an immersive virtual reality environment on curricular training for complex cognitive skills in liver surgery: a multicentric crossover randomized trial

BACKGROUND

Virtual reality (VR) is increasingly used in surgical education, but evidence of its benefits in complex cognitive training compared to conventional 3-dimensional (3D) visualization methods is lacking. The objective of this study is to assess the impact of 3D liver models rendered visible by VR or desktop interfaces (DIs) on residents' performance in clinical decision-making.

METHOD

From September 2020 to April 2021, a single-blinded, crossover randomized educational intervention trial was conducted at two university hospitals in Belgium and Italy. A proficiency-based stepwise curriculum for preoperative liver surgery planning was developed for general surgery residents. After completing the training, residents were randomized in one of two assessment sequences to evaluate ten real clinical scenarios.

RESULTS

Among the 50 participants, 46 (23 juniors/23 seniors) completed the training and were randomized. Forty residents (86.96%) achieved proficiency in decision-making. The accuracy of virtual surgical planning using VR was higher than that using DI in both groups A (8.43 ± 1.03 vs 6.86 ± 1.79, p < 0.001) and B (8.08 ± 0.9 vs 6.52 ± 1.37, p < 0.001).

CONCLUSION

Proficiency-based curricular training for liver surgery planning successfully resulted in the acquisition of complex cognitive skills. VR was superior to DI visualization of 3D models in decision-making.

CLINICALTRIALS

GOV ID

NCT04959630.

Evaluation of the SYNAPSE VINCENT for lateral lymph node dissection in rectal cancer with robotic surgery: a preliminary report

Background

Even if 3D angiographic images of preoperative contrast-enhanced computed tomography (CT) are created, the coronal and axial sections can be unclear, and thus, it is difficult to achieve projection awareness similar to that of actual laparoscopic images. In recent years, the technology of analyzing and applying medical images has advanced, and surgical simulation and navigation have been widely used to improve the safety of surgical operations. It is important to understand pelvic anatomy in the area of rectal cancer, and use of the SYNAPSE VINCENT makes it possible to simulate the anatomy before surgery, which is very useful in educating surgeons and their assistants.

Materials and methods

An important objective in surgery is to understand the anatomy of the external/internal iliac arteries and lymph nodes in lateral lymph node dissection (LLD) for rectal cancer. In this study, we explored the accuracy and usefulness of SYNAPSE VINCENT images of pelvic anatomy (especially vascular anatomy) analyzed preoperatively in two cases of LLD for rectal cancer in our department.

Results

The patients were two men aged 73 and 57 years, respectively. Both patients underwent robotic abdominal perineal resection and LLD with neoadjuvant chemoradiotherapy. The operating times for LLD were 138 and 106 min, estimated blood loss was less than 10 mL and 20 mL, and the harvested lymph nodes were nos. 21 and 22, respectively. The SYNAPSE VINCENT could be used for simulation and navigation before and during surgery. For experienced surgeons, the system helped them carry out operations more accurately.

Conclusion

In the future, surgical support using virtual reality, augmented reality, and mixed reality based on medical images will be useful and is expected to improve the safety, accuracy, and efficiency of surgery, which is extremely useful for both young and skilled surgeons preparing for difficult operations.

Essential updates 2020/2021: Current topics of simulation and navigation in hepatectomy

With the development of three‐dimensional (3D) simulation software, preoperative simulation technology is almost completely established. The remaining issue is how to recognize anatomy three‐dimensionally. Extended reality is a newly developed technology with several merits for surgical application: no requirement for a sterilized display monitor, better spatial awareness, and the ability to share 3D images among all surgeons. Various technology or devices for intraoperative navigation have also been developed to support the safety and certainty of liver surgery. Consensus recommendations regarding indocyanine green fluorescence were determined in 2021. Extended reality has also been applied to intraoperative navigation, and artificial intelligence (AI) is one of the topics of real‐time navigation. AI might overcome the problem of liver deformity with automatic registration. Including the issues described above, this article focuses on recent advances in simulation and navigation in liver surgery from 2020 to 2021.

Artificial intelligence enhances the accuracy of portal and hepatic vein extraction in computed tomography for virtual hepatectomy

BACKGROUND/PURPOSE

Current conventional algorithms used for 3-dimensional simulation in virtual hepatectomy still have difficulties distinguishing the portal vein (PV) and hepatic vein (HV). The accuracy of these algorithms was compared with a new deep-learning based algorithm (DLA) using artificial intelligence.

METHODS

A total of 110 living liver donor candidates until 2017, and 46 donor candidates until 2019 were allocated to the training group and validation groups for the DLA, respectively. All PV or HV branches were labeled based on Couinaud's segment classification and the Brisbane 2000 Terminology by hepato-biliary surgeons. Misclassified and missing branches were compared between a conventional tracking-based algorithm (TA) and DLA in the validation group.

RESULTS

The sensitivity, specificity, and Dice coefficient for the PV were 0.58, 0.98, and 0.69 using the TA; and 0.84, 0.97, and 0.90 using the DLA (P < .001, excluding specificity); and for the HV, 0.81, 087, and 0.83 using the TA; and 0.93, 0.94 and 0.94 using the DLA (P < .001 to P = .001). The DLA exhibited greater accuracy than the TA.

CONCLUSION

Compared with the TA, artificial intelligence enhanced the accuracy of extraction of the PV and HVs in computed tomography.

Application of Magnetic Resonance Imaging in Liver Biomechanics: A Systematic Review

MRI-based biomechanical studies can provide a deep understanding of the mechanisms governing liver function, its mechanical performance but also liver diseases. In addition, comprehensive modeling of the liver can help improve liver disease treatment. Furthermore, such studies demonstrate the beginning of an engineering-level approach to how the liver disease affects material properties and liver function. Aimed at researchers in the field of MRI-based liver simulation, research articles pertinent to MRI-based liver modeling were identified, reviewed, and summarized systematically. Various MRI applications for liver biomechanics are highlighted, and the limitations of different viscoelastic models used in magnetic resonance elastography are addressed. The clinical application of the simulations and the diseases studied are also discussed. Based on the developed questionnaire, the papers' quality was assessed, and of the 46 reviewed papers, 32 papers were determined to be of high-quality. Due to the lack of the suitable material models for different liver diseases studied by magnetic resonance elastography, researchers may consider the effect of liver diseases on constitutive models. In the future, research groups may incorporate various aspects of machine learning (ML) into constitutive models and MRI data extraction to further refine the study methodology. Moreover, researchers should strive for further reproducibility and rigorous model validation and verification.

Development of recognised position-guided navigation system

BACKGROUND

Previously, we developed an image-guided navigation system (IG-NS) incorporating augmented reality technology. Nevertheless, the system could still only aid the operator by presenting imagery and was short of achieving the goal of developing a real navigation system. Therefore, we developed a recognised position-guided navigation system (RP-NS) and herein reported the functionality and usefulness of this system in a phantom model for clinical applications.

METHODS

We developed RP-NS which was reconstructed by adding the positional recognition and instruction functions with the cautions by displaying the images on the monitor with a voice to the IG-NS. We evaluated accuracy of positional recognition and instruction functions using phantom model. By utilising the chronological recording of the tip position of the surgical apparatus, the surgical precision of the operators was assessed. Finally, the feasibility of improvements in surgical precision using this system was evaluated.

RESULTS

The RP-NS indicated an accuracy of the position recognition functions with an error of 2.7 mm. The surgeons could perform partial hepatectomies within mean value of 7.5% error as compared with calculated volume according to the instruction. Improvements in surgical precision using this system were obtained on the surgeons with different levels.

CONCLUSIONS

The RP-NS was highly effective as a navigation system owing to precise positional recognition and adequate instruction functions. Therefore, these results indicate that the use of this system may complement differences in proficiency, and numerically evaluate surgical skills and analyse tendencies of surgeons.

Real-time tracking of organ-shape and vessel-locations for surgical navigation using MEMS tri-axis magnetic sensors

Laparoscopic surgery is less invasive to patients; however, fatal bleeding occurs when a surgeon misinterprets the anatomical location of the blood vessels. Therefore, we have proposed a location tracking system by generating an artificial magnetic field around a patient and attaching MEMS magnetic sensor nodes to certain locations of the patient's organs for real-time tracking of the organ shape and vessel locations. This paper presents the detailed system design and configuration. The results suggest that a high spatial resolution of 1-2 mm may be achieved by static and ultralow-frequency magnetic fields for rotation recognition of each sensor node and noise cancelation of the entire system. The algorithm for creating the navigation 'map' has been investigated from both efficiency and accuracy perspectives, which is essential for practical applications of the above system in surgical navigation.

Fast and accurate nonlinear hyper-elastic deformation with a posteriori numerical verification of the convergence of solution: Application to the simulation of liver deformation

In this paper, we propose a new method to reduce the computational complexity of calculating the tangential stiffness matrix in a nonlinear finite element formulation. Our approach consists in partially updating the tangential stiffness matrix during a classic Newton-Raphson iterative process. The complexity of such an update process has the order of the number of mesh vertices to the power of two. With our approach, this complexity is reduced to the power of two of only the number of updated vertices. We numerically study the convergence of the solution with our modified algorithm. We describe the deformation through a strain energy density function which is defined with respect to the Lagrangian strain. We derive the conditions of convergence for a given tangential stiffness matrix and a given set of updated vertices. We use nonlinear geometric deformation and the nonlinear Mooney-Rivilin model with both tetrahedron and hexahedron element meshing. We provide extensive results using a cube with small and large number of elements. We provide results on nonlinearly deformed liver with multiple deformation ranges of updated vertices. We compare the proposed method to state-of-the-art work and we prove its efficiency at three levels: accuracy, speed of convergence and small radius of convergence.

Three-dimensional virtual reconstruction as a tool for preoperative planning in the management of complex anorectal fistulas

The making of three-dimensional virtual models is a promising technology in preoperative planning, but that is not used in the treatment of anorectal fistulas. The objective of this work is to describe the development and initial experience of the construction of a virtual three-dimensional model of the pelvic anatomy of a patient, allowing the exact identification of the relationships between the fistulous tracts of complex anorectal fistulas and the other pelvic structures. An MRI was performed on this patient, and the images were exported to the Vitrea fX Workstation® software. A radiologist did the analysis and segmentation of the images that were then sent to a three-dimensional image processor (Meshlab v. 1.3.3 – ISTI – CNR Research Center, Pisa University, Italy). The final 3D color image was analyzed by the surgeon and used to guide the catheterization of the fistulous pathways, the internal orifice and to assist in the identification of adjacent structures. The final three-dimensional model presented a high correlation with the intraoperative findings and facilitated the surgical planning.

Simulation and navigation liver surgery: an update after 2,000 virtual hepatectomies

The advent of preoperative 3-dimensional (3D) simulation software has made a variety of unprecedented surgical simulations possible. Since 2004, we have performed more than 2,000 preoperative simulations in the University of Tokyo Hospital, and they have enabled us to obtain a great deal of information, such as the detailed shape of liver segments, the precise volume of each segment, and the volume of hepatic venous drainage areas. As a result, we have been able to perform more aggressive and complicated surgery safely. The next step is to create a navigation system that will accurately reproduce the preoperative plan. Real-time virtual sonography (RVS) is a navigation system that provides fusion images of ultrasonography and reconstructed computed tomography images or magnetic resonance images. The RVS system facilitates the surgeon's understanding of interpretation of ultrasound images and the detection of tumors that are difficult to find by ultrasound alone. In the near future, surgical navigation systems may evolve to the point where they will be able to inform surgeons intraoperatively in real time about not only intrahepatic structures, such as vessels and tumors, but also the portal territory, hepatic vein drainage areas, and resection lines that have been planned preoperatively.

New device with force sensors for laparoscopic liver resection - investigation of grip force and histological damage

Introduction: As the benefits of minimally invasive surgery are recognized, the rate of laparoscopic liver resection (LLR) is rapidly increasing. Liver tissue is fragile compared to tissue of the stomach and colon. In endoscopic and robotic surgery, sufficient tactile sensation is yet to be obtained. Therefore, it is necessary to measure and indicate the grip force of forceps during surgery. We developed a new device consisting of force sensors and investigated its grip force and the resulting histological damage to liver tissue.Material and methods: We measured the grip force generated during laparoscopic surgery in pigs using the forceps with pressure sensors developed by us. Throughout the hepatectomy, we measured the grip force generated by the forceps in real time. We investigated the histological damage to the liver caused by using the forceps with different grip forces.Results: The subject produced a mean grip force of 1.75 N during the procedures. The maximum grip force was 3.38 N. By grasping the tissues of the liver with forceps, bleeding and destruction of the hepatic lobules were observed in a manner dependent on increasing grip force.Conclusion: The new device is necessary for preventing liver damage in laparoscopic hepatic resection.

Application of image-guided navigation system for laparoscopic hepatobiliary surgery

BACKGROUND

To achieve safety of the operation, preoperative simulation became a routine practice for hepatobiliary and pancreatic (HBP) surgery. The use of intraoperative ultrasonography (IOUS) is essential in HBP surgery. There is a limitation in the use of IOUS in laparoscopic surgery (LS), for which a new intraoperative system is expected. We have developed an image-guided navigation system (IG-NS) for open HBP surgery since 2006, and we have applied our system to LS. The aim of this study is to evaluate the results of clinical application of IG-NS in LS.

MATERIALS AND METHODS

Eight patients underwent LS using IG-NS; LS consisted of cholecystectomy and hepatectomy in four patients each. After registration, the 3D models were superimposed on the surgical field. We performed LS while observing the navigation image. Moreover, we developed a support system for operations.

RESULTS

The average registration error was 8.8 mm for LS. Repeated registration was effective for organ deformation and improved the precision of IG-NS. By using various countermeasures, identification of the tumor's position and the setting of the resection line became easy.

CONCLUSION

As IG-NS provided real-time detailed and intuitive information, this intraoperative assist system may be an effective tool in LS.

3D simulation assisted resection of giant hepatic mesenchymal hamartoma in children

OBJECTIVE

To evaluate the usefulness of Hisense Computer Assisted Surgery System (Hisense CAS) in pre-operative surgical planning and intra-operative navigation for resection of pediatric giant hepatic mesenchymal hamartoma (HMH).

METHODS

Five children with HMH underwent hepatectomy in our hospital. Pre-operative abdominal enhanced CT was performed for diagnosis and treatment planning. Using CT DICOM files, three-dimensional reconstruction was performed in three cases for operation planning and intra-operative navigation, with SID carrying out precise liver resection during the operation with Hisense CAS.

RESULT

Two patients underwent right and left lobe hepatectomy, respectively, based only on enhanced CT. In 3 patients, by using the Hisense CAS system, three-dimensional reconstruction of the liver and tumors was successfully completed, and virtual hepatectomy performed successfully according to surgical plans. Hisense CAS could clearly and directly indicate the HMH location and shape, as well as its relationship with the intra-hepatic Glisson system, assisting safe hepatectomy. All five patients recovered well from surgery without any complications, and pathological examinations confirmed that all cases were HMH. No recurrence was observed during the follow-up period of 3 months to 5 years.

CONCLUSION

Hisense CAS system is useful for preoperative planning and intra-operative navigation, assisting safer hepatectomy.

Application of three-dimensional visualization technique in preoperative planning of progressive hilar cholangiocarcinoma

OBJECTIVE

This study aims to investigate the role of three-dimensional visualization technique in the diagnosis and treatment of progressive hilar cholangiocarcinoma.

METHODS

From January 2014 to February 2017, a three-dimensional visualization model was set up in 23 patients with progressive hilar cholangiocarcinoma. The distributions and variations of the hepatic portal ducts were observed. The tumors were classified based on Bismuth classification. The simulation operation was performed and the operation plan was established.

RESULTS

All 23 patients revealed a clear relationship between the intrahepatic and extrahepatic ducts, as well as the tumors and ducts. An individualized surgery program was established through the accurate calculation of liver volume and residual liver volume. Among these patients, 13 patients completed radical resection of hilar cholangiocarcinoma combined with massive hepatectomy. No bile leakage occurred and no operative death was found.

CONCLUSION

For patients with progressive hilar cholangiocarcinoma, the optimized three-dimensional visualization technique can accurately demonstrate the dilated biliary tract system, provide a new standard to determine the presence of tumor and peripheral vascular invasion, help in establishing a reasonable individualized operation plan, reduce the incidence of bile leakage and liver failure after the operation, and improve the success rate of operation.

Virtual Reality Exploration and Planning for Precision Colorectal Surgery

BACKGROUND

Medical software can build a digital clone of the patient with 3-dimensional reconstruction of Digital Imaging and Communication in Medicine images. The virtual clone can be manipulated (rotations, zooms, etc), and the various organs can be selectively displayed or hidden to facilitate a virtual reality preoperative surgical exploration and planning.

OBJECTIVE

We present preliminary cases showing the potential interest of virtual reality in colorectal surgery for both cases of diverticular disease and colonic neoplasms.

DESIGN

This was a single-center feasibility study.

SETTINGS

The study was conducted at a tertiary care institution.

PATIENTS

Two patients underwent a laparoscopic left hemicolectomy for diverticular disease, and 1 patient underwent a laparoscopic right hemicolectomy for cancer. The 3-dimensional virtual models were obtained from preoperative CT scans. The virtual model was used to perform preoperative exploration and planning. Intraoperatively, one of the surgeons was manipulating the virtual reality model, using the touch screen of a tablet, which was interactively displayed to the surgical team.

MAIN OUTCOME MEASURES

The main outcome was evaluation of the precision of virtual reality in colorectal surgery planning and exploration.

RESULTS

In 1 patient undergoing laparoscopic left hemicolectomy, an abnormal origin of the left colic artery beginning as an extremely short common trunk from the inferior mesenteric artery was clearly seen in the virtual reality model. This finding was missed by the radiologist on CT scan. The precise identification of this vascular variant granted a safe and adequate surgery. In the remaining cases, the virtual reality model helped to precisely estimate the vascular anatomy, providing key landmarks for a safer dissection.

LIMITATIONS

A larger sample size would be necessary to definitively assess the efficacy of virtual reality in colorectal surgery.

CONCLUSIONS

Virtual reality can provide an enhanced understanding of crucial anatomical details, both preoperatively and intraoperatively, which could contribute to improve safety in colorectal surgery.

Computational Modeling in Liver Surgery

The need for extended liver resection is increasing due to the growing incidence of liver tumors in aging societies. Individualized surgical planning is the key for identifying the optimal resection strategy and to minimize the risk of postoperative liver failure and tumor recurrence. Current computational tools provide virtual planning of liver resection by taking into account the spatial relationship between the tumor and the hepatic vascular trees, as well as the size of the future liver remnant. However, size and function of the liver are not necessarily equivalent. Hence, determining the future liver volume might misestimate the future liver function, especially in cases of hepatic comorbidities such as hepatic steatosis. A systems medicine approach could be applied, including biological, medical, and surgical aspects, by integrating all available anatomical and functional information of the individual patient. Such an approach holds promise for better prediction of postoperative liver function and hence improved risk assessment. This review provides an overview of mathematical models related to the liver and its function and explores their potential relevance for computational liver surgery. We first summarize key facts of hepatic anatomy, physiology, and pathology relevant for hepatic surgery, followed by a description of the computational tools currently used in liver surgical planning. Then we present selected state-of-the-art computational liver models potentially useful to support liver surgery. Finally, we discuss the main challenges that will need to be addressed when developing advanced computational planning tools in the context of liver surgery.

Encountered-Type Haptic Interface for Representation of Shape and Rigidity of 3D Virtual Objects

This paper describes the development of an encountered-type haptic interface that can generate the physical characteristics, such as shape and rigidity, of three-dimensional (3D) virtual objects using an array of newly developed non-expandable balloons. To alter the rigidity of each non-expandable balloon, the volume of air in it is controlled through a linear actuator and a pressure sensor based on Hooke's law. Furthermore, to change the volume of each balloon, its exposed surface area is controlled by using another linear actuator with a trumpet-shaped tube. A position control mechanism is constructed to display virtual objects using the balloons. The 3D position of each balloon is controlled using a flexible tube and a string. The performance of the system is tested and the results confirm the effectiveness of the proposed principle and interface.

Novel imaging using a touchless display for computer-assisted hepato-biliary surgery

PURPOSE

We developed a touchless display system that allows the user to control the medical imaging software via hand gestures in the air. We conducted this study to verify the effectiveness of this novel touchless display system as a tool for assisting with surgical imaging.

METHODS

The patient's computed tomography (CT) data are generally observed on a display during surgery. The "Dr. aeroTAP" touchless display system was developed to generate virtual mouse events based on the position of one hand. We conducted comparative analyses of using the Dr. aeroTAP vs. using a regular mouse (control group) by measuring the time to select a 3D image from 24 thumbnail images on a screen (study 1) and to then see the CT image on the DICOM viewer (study 2).

RESULTS

We used the Dr. aeroTAP in 31 hepato-biliary operative procedures performed at our hospital. In study 1, which measured the time required to select one of 24 thumbnails, there were significant differences between the mouse and Dr. aeroTAP groups for all five surgeons who participated (P < 0.001). In study 2, there were also significant differences in the time required for CT DICOM images to be displayed (P < 0.001).

CONCLUSIONS

The touchless interface proved efficient for allowing the observation of surgical images while maintaining a sterile field during surgery.

Mediastinal pulmonary artery is associated with greater artery diameter and lingular division volume

Pulmonary vessels have numerous variation and aberrant branching patterns. Mediastinal lingular artery (MLA), the most common aberrant branch, might contribute to greater blood flow to lingular division. Hence, we investigated a correlation between lingular division volume and MLA using three-dimensional CT volumetry. We included 199 consecutive patients who underwent surveillance chest CT to detect possible malignancies in April 2015. We measured lingular division volume and cross-sectional area of lingular arteries using three-dimensional CT volumetry. MLA was identified in 58 cases (29.1%). The MLA group had significantly greater lingular division volume (median ± quartile deviation: 378.3 ± 75.5 mL vs. 330.0 ± 87.5 mL; p = 0.021) and percentage lingular division to left lung volume (19.0 ± 2.62% vs. 16.6 ± 2.39%; p < 0.001) than the non-MLA group. Total cross-sectional area of lingular arteries of the MLA group was significantly larger than that of the non-MLA group (46.1 ± 9.46 vs. 40.2 ± 5.76 mm²; p = 0.003). The total cross-sectional area of the lingular arteries strongly correlated to the percentage of lingular division to left lung volume (r = 0.689, p < 0.001). This is the first report demonstrating a positive correlation between branching pattern of pulmonary artery and lung volume.

Three-Dimensional Liver Surgery Simulation: Computer-Assisted Surgical Planning with Three-Dimensional Simulation Software and Three-Dimensional Printing<sup/>

To perform accurate hepatectomy without injury, it is necessary to understand the anatomical relationship among the branches of Glisson's sheath, hepatic veins, and tumor. In Japan, three-dimensional (3D) preoperative simulation for liver surgery is becoming increasingly common, and liver 3D modeling and 3D hepatectomy simulation by 3D analysis software for liver surgery have been covered by universal healthcare insurance since 2012. Herein, we review the history of virtual hepatectomy using computer-assisted surgery (CAS) and our research to date, and we discuss the future prospects of CAS. We have used the SYNAPSE VINCENT medical imaging system (Fujifilm Medical, Tokyo, Japan) for 3D visualization and virtual resection of the liver since 2010. We developed a novel fusion imaging technique combining 3D computed tomography (CT) with magnetic resonance imaging (MRI). The fusion image enables us to easily visualize anatomic relationships among the hepatic arteries, portal veins, bile duct, and tumor in the hepatic hilum. In 2013, we developed an original software, called Liversim, which enables real-time deformation of the liver using physical simulation, and a randomized control trial has recently been conducted to evaluate the use of Liversim and SYNAPSE VINCENT for preoperative simulation and planning. Furthermore, we developed a novel hollow 3D-printed liver model whose surface is covered with frames. This model is useful for safe liver resection, has better visibility, and the production cost is reduced to one-third of a previous model. Preoperative simulation and navigation with CAS in liver resection are expected to help planning and conducting a surgery and surgical education. Thus, a novel CAS system will contribute to not only the performance of reliable hepatectomy but also to surgical education.

Prediction of Embolization Area after Conventional Transcatheter Arterial Chemoembolization for Hepatocellular Carcinoma Using SYNAPSE VINCENT

PURPOSE

Transcatheter arterial chemoembolization (TACE) is one of the most effective therapeutic options for hepatocellular carcinoma (HCC) and it is important to protect residual liver function after treatment as well as the effect. To reduce the liver function deterioration, we evaluated the automatic software to predict the embolization area of TACE in 3 dimensions.

MATERIALS AND METHODS

Automatic prediction software of embolization area was used in chemoembolization of 7 HCCs. Embolization area of chemoembolization was evaluated within 1 week CT findings after TACE and compared simulated area using automatic prediction software.

RESULTS

The maximal diameter of these tumors is in the range 12-42 mm (24.6 ± 9.5 mm). The average time for detecting tumor-feeding branches was 242 s. The total time to detect tumor-feeding branches and simulate the embolization area was 384 s. All cases could detect all tumor-feeding branches of HCC, and the expected embolization area of simulation with automatic prediction software was almost the same as the actual areas, as shown by CT after TACE.

CONCLUSION

This new technology has possibilities to reduce the amount of contrast medium used, protect kidney function, decrease radiation exposure, and improve the therapeutic effect of TACE.

Usefulness of three-dimensional(3D) simulation software in hepatectomy for pediatric hepatoblastoma. Surg Oncol. 2016;25:236-243. [PMID: 27566028 DOI: 10.1016/j.suronc.2016.05.023]

BACKGROUND

Hepatoblastoma (HB) is the most common malignant liver tumor in childhood. Complete HB surgical resection which is technically demanding is the cornerstone of effective therapy with a good prognosis. The aim of our study is to evaluate the usefulness of 3D simulation software in assisting hepatectomy in pediatric patients with HB.

METHODS

21 children with HB who underwent hepatectomy were enrolled in this study. All patients underwent computer tomography (CT) imaging preoperatively. CT images from 11 cases (from September 2013 to August 2015) were reconstructed with Hisense CAS, and performed hetpatectomy. While 10 cases (from September 2011 to August 2013) without 3D simulation were token as the control group. The clinical outcome were analyzed and compared between the 2 groups.

RESULTS

All the HB were successfully removed for all patients and there was no positive margins in the surgical specimens, no complications, and no recurrences. For the reconstructing group, 3D simulation software successfully reconstructed the 3D images of liver and were used as a navigator in the operation room during hepatectomy. Anatomic hepatectomy were successfully completed for all patients after operation planning using the software. There was no obvious discrepancy between the virtual and the actual hepatectomy. The mean operation time was shorter (142.18 ± 21.87 min VS. the control group, 173.5 ± 54.88 min, p = 0.047) and intraoperative bleeding was less (28.73 ± 14.17 ml VS. 42.8 ± 41.12 ml, p = 0.011) in the reconstructing group. Moreover, postoperative hospital stay tended to be shorter in the reconstructing group (11.18 ± 2.78d VS. the control group 13 ± 3.46d, P = 0.257).

CONCLUSIONS

3D simulation software facilitates the investigation of the complex liver structure, contributes to the optimal operation planning, and enables an individualized anatomic hepatectomy for each pediatric patient with HB.