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

International multidisciplinary consensus recommendations on clinical application of three-dimensional visualization in precision surgery for pediatric liver tumors

BACKGROUND

Pediatric liver tumors are predominantly primary malignant tumors, and complete tumor resection with sufficient preservation of liver tissue is crucial for improving prognosis. However, due to the delicate anatomical structure of the pediatric liver and the relatively large size of the tumors, especially in difficult cases, the surgical challenges are substantial. While precision liver surgery are widely applied in clinical practice, pediatric cases require more customized approaches. The application of three-dimensional (3D) visualization technology is crucial for enhancing surgical accuracy, allowing for precise preoperative planning and intraoperative guidance.

METHODS

This consensus was collaboratively developed by 36 experts from eight countries, using the Glaser's state-of-the-art method to review and refine the draft.

RESULTS

The final consensus resulted in 15 international multidisciplinary consensus recommendations on clinical application of 3D visualization in precision surgery for pediatric liver tumors.

CONCLUSION

This consensus will standardize the application of 3D visualization technology in precision surgery for pediatric liver tumors to improve outcomes and reduce risks.

[Virtual reality in liver surgery-Planning, advanced training, testing]

Anatomical structures of the liver could be reconstructed three dimensionally from preoperative cross-sectional imaging for over 20 years. This three-dimensional (3D) representation not only optimizes the preoperative planning options but also the communication of specific operation-relevant structures can be improved using 3D models. In addition to a plastic and interactive visualization of 3D organ models, the disruptive technology of virtual reality (VR) can also provide a possibility for structured training and further education regarding surgical anatomy of the liver and operation planning. This makes examinations in virtual reality also seem tangible. The latest prototypes even enable patient-specific simulation of intraoperative sonography. This review article provides an overview of the current status of available technologies for training and further education using VR exemplified by liver surgery.

Enhancing surgical planning for abdominal tumors in children through advanced 3D visualization techniques: a systematic review of future prospects

Introduction

Preoperative three-dimensional (3D) reconstruction using sectional imaging is increasingly used in challenging pediatric cases to aid in surgical planning. Many case series have described various teams' experiences, discussing feasibility and realism, while emphasizing the technological potential for children. Nonetheless, general knowledge on this topic remains limited compared to the broader research landscape. The aim of this review was to explore the current devices and new opportunities provided by preoperative Computed Tomography (CT) scans or Magnetic Resonance Imaging (MRI).

Methods

A systematic review was conducted to screen pediatric cases of abdominal and pelvic tumors with preoperative 3D reconstruction published between 2000 and 2023.

Discussion

Surgical planning was facilitated through virtual reconstruction or 3D printing. Virtual reconstruction of complex tumors enables precise delineation of solid masses, formulation of dissection plans, and suggests dedicated vessel ligation, optimizing tissue preservation. Vascular mapping is particularly relevant for liver surgery, large neuroblastoma with imaging-defined risk factors (IDRFs), and tumors encasing major vessels, such as complex median retroperitoneal malignant masses. 3D printing can facilitate specific tissue preservation, now accessible with minimally invasive procedures like partial nephrectomy. The latest advancements enable neural plexus reconstruction to guide surgical nerve sparing, for example, hypogastric nerve modelling, typically adjacent to large pelvic tumors. New insights will soon incorporate nerve plexus images into anatomical segmentation reconstructions, facilitated by non-irradiating imaging modalities like MRI.

Conclusion

Although not yet published in pediatric surgical procedures, the next anticipated advancement is augmented reality, enhancing real-time intraoperative guidance: the surgeon will use a robotic console overlaying functional and anatomical data onto a magnified surgical field, enhancing robotic precision in confined spaces.

Questionnaire survey of virtual reality experiences of digestive surgery at a rural academic institute: A pilot study for pre-surgical education

We developed a prototype VR platform, VECTORS L&M (VLM), aiming to enhance the understanding of digestive surgery for students, interns, and young surgeons by limiting costs. Its efficacy was assessed via questionnaires before implementation in surgical education. The VLM provides nine-minute VR views of surgeries, from both 180- and 360-degree angles. It was created with L.A.B. Co., Ltd. and incorporates surgery videos from biliary malignancy patients. Following VLM development, a survey was conducted among surgeons who had experienced it. Twenty-eight participants (32% of observers) responded to the survey. A majority (81%) reported positive experiences with the VR content and showed interest in VR video production, though some reported sickness. Most respondents were experienced surgeons, and nearly all believed VR was important for medical education with a mean score of 4.14 on a scale of up to 5. VR was preferred over 3D printed models due to its application versatility. Participants expressed the desire for future VR improvements, such as increased mobility, cloud connectivity, cost reduction, and better resolution. The VLM platform, coupled with this innovative teaching approach, offers experiential learning in intraabdominal surgery, effectively enriching the knowledge of students and surgeons ahead of surgical education and training.

Automated 3D liver segmentation from hepatobiliary phase MRI for enhanced preoperative planning

Recent advancements in deep learning have facilitated significant progress in medical image analysis. However, there is lack of studies specifically addressing the needs of surgeons in terms of practicality and precision for surgical planning. Accurate understanding of anatomical structures, such as the liver and its intrahepatic structures, is crucial for preoperative planning from a surgeon's standpoint. This study proposes a deep learning model for automatic segmentation of liver parenchyma, vascular and biliary structures, and tumor mass in hepatobiliary phase liver MRI to improve preoperative planning and enhance patient outcomes. A total of 120 adult patients who underwent liver resection due to hepatic mass and had preoperative gadoxetic acid-enhanced MRI were included in the study. A 3D residual U-Net model was developed for automatic segmentation of liver parenchyma, tumor mass, hepatic vein (HV), portal vein (PV), and bile duct (BD). The model's performance was assessed using Dice similarity coefficient (DSC) by comparing the results with manually delineated structures. The model achieved high accuracy in segmenting liver parenchyma (DSC 0.92 ± 0.03), tumor mass (DSC 0.77 ± 0.21), hepatic vein (DSC 0.70 ± 0.05), portal vein (DSC 0.61 ± 0.03), and bile duct (DSC 0.58 ± 0.15). The study demonstrated the potential of the 3D residual U-Net model to provide a comprehensive understanding of liver anatomy and tumors for preoperative planning, potentially leading to improved surgical outcomes and increased patient safety.

Impact of patient-specific three-dimensional printed liver models on hepatic surgery safety: a pilot study

BACKGROUND

Simulation and navigation technologies in hepatobiliary surgery have been developed recently. In this prospective clinical trial, we evaluated the accuracy and utility of our patient-specific three dimensional (3D)-printed liver models as an intraoperative navigation system to ensure surgical safety.

METHOD

Patients requiring advanced hepatobiliary surgeries during the study period were enrolled. Three cases were selected for comparison of the computed tomography (CT) scan data of the models with the patients' original data. Questionnaires were completed after surgeries to evaluate the utility of the models. Psychological stress was used as subjective data and operation time and blood loss as objective data.

RESULTS

Thirteen patients underwent surgery using the patient-specific 3D liver models. The difference between patient-specific 3D liver models and the original data was less than 0.6 mm in the 90% area. The 3D model assisted with intra-liver hepatic vein recognition and the definition of the cutting line. According to the post-operative subjective evaluation, surgeons found the models improved safety and reduced psychological stress during operations. However, the models did not reduce operative time or blood loss.

CONCLUSION

The patient-specific 3D-printed liver models accurately reflected patients' original data and were an effective intraoperative navigation tool for meticulously difficult liver surgeries.

CLINICAL TRIAL REGISTRATION

This study was registered in the UMIN Clinical Trial Registry (UMIN000025732).

Combining 99mTc-GSA single-photon emission-computed tomography and Gd-EOB-DTPA-enhanced magnetic resonance imaging for staging liver fibrosis

Preoperative assessment of the degree of liver fibrosis is important to determine treatment strategies. In this study, galactosyl human serum albumin single-photon emission-computed tomography and ethoxybenzyl (EOB) contrast-enhanced magnetic resonance imaging (MRI) were used to assess the changes in hepatocyte function after liver fibrosis, and the standardized uptake value (SUV) was combined with gadolinium EOB-diethylenetriaminepentaacetic acid to evaluate its added value for liver fibrosis staging. A total of 484 patients diagnosed with hepatocellular carcinoma who underwent liver resection between January 2010 and August 2018 were included. Resected liver specimens were classified based on pathological findings into nonfibrotic and fibrotic groups (stratified according to the Ludwig scale). Galactosyl human serum albumin-single-photon emission-computed tomography and EOB contrast-enhanced MRI examinations were performed, and the mean SUVs (SUVmean) and contrast enhancement indices (CEIs) were obtained. The diagnostic value of the acquired SUV and CEIs for fibrosis was assessed by calculating the area under the receiver operating characteristic curve (AUC). In the receiver operating characteristic analysis, SUV + CEI showed the highest AUC in both fibrosis groups. In particular, in the comparison between fibrosis groups, SUV + CEI showed significantly higher AUCs than SUV and CEI alone in discriminating between fibrosis (F3 and 4) and no or mild fibrosis (F0 and 2) (AUC: 0.879, vs SUV [P = 0.008], vs. CEI [P = 0.023]), suggesting that the combination of SUV + CEI has greater diagnostic performance than the individual indices. Combining the SUV and CEI provides high accuracy for grading liver fibrosis, especially in differentiating between grades F0 and 2 and F3-4. SUV and gadolinium EOB-diethylenetriaminepentaacetic acid-enhanced MRI can be noninvasive diagnostic methods to guide the selection of clinical treatment options for patients with liver diseases.

Value of 3D printing technology combined with indocyanine green fluorescent navigation in complex laparoscopic hepatectomy

Background

Laparoscopic hepatectomy (LH) has achieved rapid progress over the last decade. However, it is still challenging to apply laparoscopy to lesions located in segments I, VII, VIII, and IVa and the hepatic hilar region due to difficulty operating around complex anatomical structures. In this study, we applied three-dimensional printing (3DP) and indocyanine green (ICG) fluorescence imaging technology to complex laparoscopic hepatectomy (CLH) to explore the effects and value of the modified procedure.

Materials and methods

From January 2019 to January 2021, 54 patients with complex hepatobiliary diseases underwent LH at our center. Clinical data were collected from these patients and retrospectively analyzed.

Results

A total of 30 patients underwent CLH using the conventional approach, whereas 24 cases received CLH with 3DP technology and ICG fluorescent navigation. Preoperative data were compared between the two groups. In the 3DP group, we modified the surgical strategy of four patients (4/24, 16.7%) due to real-time intraoperative navigation with 3DP and ICG fluorescent imaging technology. We did not modify the surgical strategy for any patient in the non-3DP group (P = 0.02). There were no significant differences between the non-3DP and 3DP groups regarding operating time (297.7±104.1 min vs. 328.8±110.9 min, P = 0.15), estimated blood loss (400±263.8 ml vs. 345.8±356.1 ml, P = 0.52), rate of conversion to laparotomy (3/30 vs. 2/24, P = 0.79), or pathological outcomes including the incidence of microscopical R0 margins (28/30 vs. 24/24, P = 0.57). Additionally, there were no significant differences in postoperative complications or recovery conditions between the two groups. No instances of 30- or 90-day mortality were observed.

Conclusion

The optimal surgical strategy for CLH can be chosen with the help of 3DP technology and ICG fluorescent navigation. This modified procedure is both safe and effective, but without improvement of intraoperative and short-term outcomes.

Leberchirurgie 4.0 - OP-Planung, Volumetrie, Navigation und Virtuelle Realität

Durch die Optimierung der konservativen Behandlung, die Verbesserung der bildgebenden Verfahren und die Weiterentwicklung der Operationstechniken haben sich das operative Spektrum sowie der Maßstab für die Resektabilität in Bezug auf die Leberchirurgie in den letzten Jahrzehnten deutlich verändert.

Dank zahlreicher technischer Entwicklungen, insbesondere der 3-dimensionalen Segmentierung, kann heutzutage die präoperative Planung und die Orientierung während der Operation selbst, vor allem bei komplexen Eingriffen, unter Berücksichtigung der patientenspezifischen Anatomie erleichtert werden.

Neue Technologien wie 3-D-Druck, virtuelle und augmentierte Realität bieten zusätzliche Darstellungsmöglichkeiten für die individuelle Anatomie. Verschiedene intraoperative Navigationsmöglichkeiten sollen die präoperative Planung im Operationssaal verfügbar machen, um so die Patientensicherheit zu erhöhen.

Dieser Übersichtsartikel soll einen Überblick über den gegenwärtigen Stand der verfügbaren Technologien sowie einen Ausblick in den Operationssaal der Zukunft geben.

Influence of Three-Dimensional Visual Reconstruction Technology Combined with Virtual Surgical Planning of CTA Images on Precise Resection of Liver Cancer in Hepatobiliary Surgery

Hepatobiliary malignancies, such as hepatocellular carcinoma (HCC) and biliary tract cancers, namely, gallbladder carcinoma and cholangiocarcinoma, are linked to a high rate of morbidity and mortality, depending on the phase of the disease. The intricate hepatobiliary anatomy and the need for accurate peroperative management, especially in patients with advanced liver disease, make these tumors difficult to treat. Surgical resection is a notable therapy for hepatobiliary cancers. Unnecessary or excessive liver excision influences patient rehabilitation, normal liver function, and postoperative complications. Hepatobiliary operations must therefore include accurate liver removal. The present advancements in imaging technology are aimed at improving the diagnostic efficacy of liver injury even more. Three-dimensional visual reconstruction is becoming more important in the diagnosis as well as treatment of a variety of disorders. In this paper, we proposed a novel three-dimensional visual reconstruction technology using enhanced nonuniform rational basis spline (ENURBS) combined with virtual surgical planning of Computed Tomography Angiography (CTA) images for precise liver cancer resection. The purpose of this project is to rebuild 2D CTA scan images of liver cancer into a 3D reconstructed model for efficient visualization and diagnosis of liver cancer and to prepare an effective preoperative surgical plan for precise liver excision based on a 3D recreated liver model. This method's performance is compared to that of 2D planning in terms of accuracy and time taken to complete the plan. It is concluded that our proposed technique outperforms the planning technique based on 2D images.

The Application of Three-Dimensional Technologies in the Improvement of Orthopedic Surgery Training and Medical Education Quality: A Comparative Bibliometrics Analysis

Orthopedics is a medical specialty that focuses on the clinical treatment and care of the musculoskeletal system. Orthopedics is a medical specialty which specializing in the clinical treatment and nursing of musculoskeletal system. The education of orthopedics is often serious and difficult because of the high technical requirements, complicated anatomical knowledge and long study process. However, medical students or junior residents rarely have the opportunity to see such orthopedic surgery or attend preclinical practice, which limits the opportunities for training clinicians. Hopefully, with the increasing use of three-dimensional (3D) technologies in medical teaching, this situation can be alleviated. In this study, we demonstrate that different 3D technologies can effectively simulate orthopedic surgery with very high accuracy. We carefully evaluated the use of 3D technologies in primary medical teaching and proposed a vision for the future. We searched and screened 3,997 publications from the Web of Science Core Collection (WoSCC) on 22 Oct 2021 with (trauma) AND ((education) OR (training) OR (teaching) OR (learning)) AND ((3D) OR (Three Dimensional)), (Joint) AND ((education) OR (training) OR (teaching) OR (learning)) AND ((3D) OR (Three Dimensional)), (spine) AND ((education) OR (training) OR (teaching) OR (learning)) AND ((3D) OR (Three Dimensional)) as the search strategy. Then, we eliminated the publications irrelevant to “orthopedics” AND/OR “orthopaedic” (in United Kingdom English), the final number of publications are 440 for trauma surgery, 716 for joint surgery and 363 for spine surgery, a visual display of comprehensive information analysis was made by VOSviewer. Next, we read and analyzed retrieved articles extensively according to the selection criteria, 11 highly cited publications on three major branches of orthopedics were chosen. The extracted data included the authors, purpose, methods, results and benefits/limitations. The evaluation of these studies directly and objectively proved the superiority of 3D technologies in orthopedics. Furthermore, the material usage and strength of 3D technologies can be closer to the real situation, which will help improve their effectiveness in teaching. We hope that more relevant studies will be conducted to continue examining the effects of 3D technologies on orthopedic medical education as well as orthopedic surgery training, and we hope that this technique can be more widely used in the clinical teaching of orthopedics to train clinicians on learning medical theory and surgical technology quickly and efficiently.

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.

Virtual reality and 3D printing improve preoperative visualization of 3D liver reconstructions-results from a preclinical comparison of presentation modalities and user's preference

Background

Preoperative three-dimensional (3D) reconstructions for liver surgery planning have been shown to be effective in reduction of blood loss and operation time. However, the role of the ‘presentation modality’ is not well investigated. We present the first study to compare 3D PDFs, 3D printed models (PR) and virtual reality (VR) 3D models with regard to anatomical orientation and personal preferences in a high volume liver surgery center.

Methods

Thirty participants, 10 medical students, 10 residents, 5 fellows and 5 hepatopancreatobiliary (HPB) experts, assigned the tumor-bearing segments of 20 different patient’s individual liver reconstructions. Liver models were presented in a random order in all modalities. Time needed to specify the tumor location was recorded. In addition, a score was calculated factoring in correct, wrong and missing segment assignments. Furthermore, standardized test/questionnaires for spatial thinking and seeing, vegetative side effects and usability were completed.

Results

Participants named significantly more correct segments in VR (P=0.040) or PR (P=0.036) compared to PDF. Tumor assignment was significantly shorter with 3D PR models compared to 3D PDF (P<0.001) or VR application (P<0.001). Regardless of the modality, HPB experts were significantly faster (24±8 vs. 35±11 sec; P=0.014) and more often correct (0.87±0.12 vs. 0.83±0.15; P<0.001) than medical students. Test results for spatial thinking and seeing had no influence on time but on correctness of tumor assignment. Regarding usability and user experience the VR application achieved the highest scores without causing significant vegetative symptoms and was also the most preferred method (n=22, 73.3%) because of the multiple functions like scaling and change of transparency. Ninety percent (n=27) stated that this application can positively influence the operation planning.

Conclusions

3D PR models and 3D VR models enable a better and partially faster anatomical orientation than reconstructions presented as 3D PDFs. User’s preferred the VR application over the PR models and PDF. A prospective trial is needed to evaluate the different presentation modalities regarding intra- and postoperative outcomes.

[Systematic review of current trends in preoperative planning of surgery for liver tumors]

The purpose of the study was a systematic review of current trends in preoperative planning of surgery for liver tumors. These data will be valuable to determine the advantages and disadvantages of 3D modeling, augmented reality technology and 3D printing in preoperative planning of surgery for focal liver lesions.

Three-Dimensional Printed Anatomic Models Derived From Magnetic Resonance Imaging Data: Current State and Image Acquisition Recommendations for Appropriate Clinical Scenarios

Three-dimensional (3D) printing technologies have been increasingly utilized in medicine over the past several years and can greatly facilitate surgical planning thereby improving patient outcomes. Although still much less utilized compared to computed tomography (CT), magnetic resonance imaging (MRI) is gaining traction in medical 3D printing. The purpose of this study was two-fold: 1) to determine the prevalence in the existing literature of using MRI to create 3D printed anatomic models for surgical planning and 2) to provide image acquisition recommendations for appropriate clinical scenarios where MRI is the most suitable imaging modality. The workflow for creating 3D printed anatomic models from medical imaging data is complex and involves image segmentation of the regions of interest and conversion of that data into 3D surface meshes, which are compatible with printing technologies. CT is most commonly used to create 3D printed anatomic models due to the high image quality and relative ease of performing image segmentation from CT data. As compared to CT datasets, 3D printing using MRI data offers advantages since it provides exquisite soft tissue contrast needed for accurate organ segmentation and it does not expose patients to unnecessary ionizing radiation. MRI, however, often requires complicated imaging techniques and time-consuming postprocessing procedures to generate high-resolution 3D anatomic models needed for 3D printing. Despite these challenges, 3D modeling and printing from MRI data holds great clinical promises thanks to emerging innovations in both advanced MRI imaging and postprocessing techniques. EVIDENCE LEVEL: 2 TECHNICAL EFFICATCY: 5.

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.

Outcomes of surgery for giant hepatic hemangioma

BACKGROUND

The surgical indications for liver hemangioma remain unclear.

METHODS

Data from 152 patients with hepatic hemangioma who underwent hepatectomy between 2004 and 2019 were retrospectively reviewed. We analyzed characteristics including tumor size, surgical parameters, and variables associated with Kasabach-Merritt syndrome and compared the outcomes of laparoscopic and open hepatectomy. Here, we describe surgical techniques for giant hepatic hemangioma and report on two meaningful cases.

RESULTS

Most (63.8%) patients with hepatic hemangioma were asymptomatic. Most (86.4%) tumors from patients with Kasabach-Merritt syndrome were larger than 15 cm. Enucleation (30.9%), sectionectomy (28.9%), hemihepatectomy (25.7%), and the removal of more than half of the liver (14.5%) were performed through open (87.5%) and laparoscopic (12.5%) approaches. Laparoscopic hepatectomy is associated with an operative time, estimated blood loss, and major morbidity and mortality rate similar to those of open hepatectomy, but a shorter length of stay. 3D image reconstruction is an alternative for diagnosis and surgical planning for partial hepatectomy.

CONCLUSION

The main indication for surgery is giant (> 10 cm) liver hemangioma, with or without symptoms. Laparoscopic hepatectomy was an effective option for hepatic hemangioma treatment. For extremely giant hemangiomas, 3D image reconstruction was indispensable. Hepatectomy should be performed by experienced hepatic surgeons.

Preoperative 3D reconstruction images for paediatric tumours: Advantages and drawbacks

RATIONALE

Three-dimensional reconstruction (3DR) of preoperative images may improve the presurgical assessment of tumours prior to removal. We aimed to analyse the advantages and discrepancies of preoperative 3DR in paediatric tumours.

METHODS

We conducted a prospective observational study from 2016 to 2019, including patients with thoraco-abdominal tumours having predictable surgical risks on preoperative images (encasement of vessels posing vascular risks, ie, neuroblastic and soft tissue tumours or parenchyma preservation of the invaded organ, ie, liver and kidney). A comparison of 2D/3DR and surgical findings was performed.

RESULTS

Twenty-four patients, with a median age at surgery of 68.2 months (13 days-203 months), were operated on for neuroblastoma (n = 7), renal tumour (n = 7), hepatic tumour (n = 4) and others (n = 6; bone sarcoma of the iliac branch, abdominal lymph nodes of a recurrent testicular germ cell tumour, pseudoinflammatory tumour of the omentum, thoracic lipoblastoma, desmoplastic tumour, solid and pseudopapillar tumour of the pancreas). Reconstruction was of poor quality in two patients with renal tumours because computed tomography (CT) had no excretory phase. Discrepancies between 3DR and surgical findings occurred in two patients, one because of poor assessment of caliceal infiltration by renal nodules and the other because of inadequate reconstruction of renal vein thrombosis. For all the other tumours, 3DR improved the visualisation and precise location of vessels during surgery.

CONCLUSION

High-quality preoperative images are mandatory to provide the best 3DR. In the majority of cases, 3DR is of significant help during surgery to better identify vascular structures within tumours and preserve parenchyma.

Image guidance using two-dimensional illustrations and three-dimensional modeling of donor anatomy during living donor hepatectomy

BACKGROUND

For living donor liver transplantation, preoperative imaging is required for the safety of both the donor and the recipient. We previously initiated our image-guidance program using two-dimensional illustrations and three-dimensional modeling in September 2018; herein, we analyzed the resultant changes in the clinical outcomes.

METHODS

Living donors and recipients who underwent liver transplantation between September 2017 and August 2019 were included. Cases with image guidance were compared to those without image guidance regarding the operative outcome, especially bile-duct opening in the graft as well as surgical complications.

RESULTS

Among 200 living donor transplantation, 90 transplantations were completed with image guidance. The image-guidance group had a higher rate of laparoscopy (80.9% vs. 97.8%; p < .001) as compared with the group without image guidance. Although there was no difference in the type of bile duct (p = .144), more grafts with single bile-duct openings were found in the image-guidance group (52.7% vs. 80.0%; p = .001). Consequently, achievements in bile-duct openings were superior in the image-guidance group (p = .022). There were no differences in bile leakage, graft failure, or number of deaths during the first month post-transplantation.

CONCLUSION

As we initiated our image-guidance program for living donor liver transplantation, clinical outcomes, especially bile-duct division, were improved relative to before implementation.

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.

Effective dose for multiple and repeated radiation examinations in donors and recipients of adult-to-adult living donor liver transplants at a single center

PURPOSE

To evaluate the effective doses received by donors and recipients, identify effective dose contributions, and make risk assessments.

MATERIALS AND METHODS

It was a retrospective study. 100 Donors and 100 recipients were enrolled with an operative day from March 2016 to August 2017. The dose was analyzed for all radiation-related examinations over a period of 2 years, 1 year before and 1 year after the LDLT procedure. The effective doses of plain X-rays, CT, fluoroscopy, and nuclear medicine per patient were simulated by a Monte Carlo software, evaluated by the dose-length product conversion factors, evaluated by the dose-area product conversion factors, and evaluated by the activity conversion factors, respectively. The risks of radiation-induced cancer were assessed on the basis of the ICRP risk model.

RESULTS

The median effective doses were 71 (range: 30-186) mSv for donors and 147 (32-423) mSv for recipients. The radiation examinations were mainly performed in the last three months of preoperative period to first month of postoperative period for recipients and donors. The HCC recipients received a higher effective dose, 195 (64-423) mSv, than those with other indications. The median radiation-induced cancer risk was 0.38 % in male and 0.48 % in female donors and was 0.50 % in male and 0.58 % in female recipients.

CONCLUSION

Donors and recipients received a large effective dose, mainly from the CT scans. To reduce effective doses should be included in future challenges in some living donor liver transplants centers that often use CT examinations.

Application of three-dimensional reconstruction and virtual reality technology in liver surgery

After three-dimensional (3D) reconstruction of the two-dimensional information obtained from routine computed tomography or magnetic resonance imaging examinations of the liver using software, surgeons can examine the volume of the liver, anatomical variation, the course of intrahepatic vessels, the location of the tumor, and its relationship with the surrounding vessels more intuitively, vividly, and from multiple angles. Preoperative 3D reconstruction and virtual reality technology can realize the measurement of liver volume and the implementation of simulated hepatectomy, which can further clarify the scope of surgical resection and ensure the residual liver volume and function to meet the needs of patients after operation. The virtual operation and image navigation before and during the operation can also prevent the injury to important blood vessels and bile ducts in the liver during the operation, significantly shorten the operation time, reduce the bleeding during the operation, and reduce the occurrence of complications such as liver dysfunction, bile leakage, and bleeding after the operation.

Consensus recommendations of three-dimensional visualization for diagnosis and management of liver diseases

Three-dimensional (3D) visualization involves feature extraction and 3D reconstruction of CT images using a computer processing technology. It is a tool for displaying, describing, and interpreting 3D anatomy and morphological features of organs, thus providing intuitive, stereoscopic, and accurate methods for clinical decision-making. It has played an increasingly significant role in the diagnosis and management of liver diseases. Over the last decade, it has been proven safe and effective to use 3D simulation software for pre-hepatectomy assessment, virtual hepatectomy, and measurement of liver volumes in blood flow areas of the portal vein; meanwhile, the use of 3D models in combination with hydrodynamic analysis has become a novel non-invasive method for diagnosis and detection of portal hypertension. We herein describe the progress of research on 3D visualization, its workflow, current situation, challenges, opportunities, and its capacity to improve clinical decision-making, emphasizing its utility for patients with liver diseases. Current advances in modern imaging technologies have promised a further increase in diagnostic efficacy of liver diseases. For example, complex internal anatomy of the liver and detailed morphological features of liver lesions can be reflected from CT-based 3D models. A meta-analysis reported that the application of 3D visualization technology in the diagnosis and management of primary hepatocellular carcinoma has significant or extremely significant differences over the control group in terms of intraoperative blood loss, postoperative complications, recovery of postoperative liver function, operation time, hospitalization time, and tumor recurrence on short-term follow-up. However, the acquisition of high-quality CT images and the use of these images for 3D visualization processing lack a unified standard, quality control system, and homogeneity, which might hinder the evaluation of application efficacy in different clinical centers, causing enormous inconvenience to clinical practice and scientific research. Therefore, rigorous operating guidelines and quality control systems need to be established for 3D visualization of liver to develop it to become a mature technology. Herein, we provide recommendations for the research on diagnosis and management of 3D visualization in liver diseases to meet this urgent need in this research field.

Radiological Society of North America (RSNA) 3D Printing Special Interest Group (SIG) clinical situations for which 3D printing is considered an appropriate representation or extension of data contained in a medical imaging examination: abdominal, hepatobiliary, and gastrointestinal conditions

Background

Medical 3D printing has demonstrated value in anatomic models for abdominal, hepatobiliary, and gastrointestinal conditions. A writing group composed of the Radiological Society of North America (RSNA) Special Interest Group on 3D Printing (SIG) provides appropriateness criteria for abdominal, hepatobiliary, and gastrointestinal 3D printing indications.

Methods

A literature search was conducted to identify all relevant articles using 3D printing technology associated with a number of abdominal pathologic processes. Each included study was graded according to published guidelines.

Results

Evidence-based appropriateness guidelines are provided for the following areas: intra-hepatic masses, hilar cholangiocarcinoma, biliary stenosis, biliary stones, gallbladder pathology, pancreatic cancer, pancreatitis, splenic disease, gastric pathology, small bowel pathology, colorectal cancer, perianal fistula, visceral trauma, hernia, abdominal sarcoma, abdominal wall masses, and intra-abdominal fluid collections.

Conclusion

This document provides initial appropriate use criteria for medical 3D printing in abdominal, hepatobiliary, and gastrointestinal conditions.

Robot-assisted partial nephrectomy of initial cases using a 3D square-block type kidney model

Background

It is extremely important to understand the local anatomy prior to performing appropriate and efficient robot-assisted partial nephrectomies (RAPNs).

Methods

We developed a personalized three-dimensional printed kidney model of square-block type to enhance our knowledge and understanding on the underlying anatomy during RAPN, and we consequently applied this model to six initial cases of RAPN.

Results

The mean warm ischemic time was 18 minutes and the mean estimated blood loss was 59 mL. Only one patient presented with a minor complication, whereas all six patients included in this study were surgical margin negative.

Conclusions

We believe that this cost-effective model helped us in understanding the underlying local anatomy and facilitating an increased efficiency in the related surgery. Further studies are required to validate our preliminary results.

Preoperative three-dimensional versus two-dimensional evaluation in assessment of patients undergoing major liver resection for hepatocellular carcinoma: a propensity score matching study

Background

Compared with 2D evaluation, 3D evaluation possesses the virtues of displaying spatial anatomy of intrahepatic blood vessels and its relations to tumors, and enabling calculation of liver volumes, thus facilitating preoperative surgery planning.

Methods

The objective of this study is to study whether preoperative 3D (three-dimensional) evaluation produced better long-term overall survival (OS) outcomes compared to the traditional 2D (two-dimensional) evaluation in patients who underwent major hepatectomy for hepatocellular carcinoma (HCC). This retrospective study matched patients who underwent preoperative 2D evaluation with those who underwent preoperative 3D evaluation in a 1:1 ratio using propensity score matching. The primary endpoints were long-term survival outcomes in the two groups after major hepatectomy for HCC.

Results

Of the 248 patients in each of the 2 matched groups, the baseline characteristics were comparable. The median follow-up for all patients was 36 months (range, 0-40 months). The 3-year OS of patients in the PSM cohort was 38.5%. Compared with the 2D Group, patients in the 3D Group had a better OS rate (HR 0.722, 95% CI: 0.556-0.938, P=0.015) and disease-free survival (DFS) rate (HR 0.741, 95% CI: 0.590-0.929, P=0.009). The 3-year OS and DFS rate for the 3D Group versus the 2D group were 58.9% and 44.0% versus 47.4% and 33.1%, respectively.

Conclusions

3D preoperative evaluation resulted in significantly better intermediate-term (3-year) overall survival rate than the traditional 2D evaluation.

Modeling the hepatic arterial flow in living liver donor after left hepatectomy and postoperative boundary condition exploration

Preoperative and postoperative hepatic perfusion is modeled with one-dimensional (1-D) Navier-Stokes equations. Flow rates obtained from ultrasound (US) data and impedance resulted from structured trees are the inflow and outflow boundary condition (BC), respectively. Structured trees terminate at the size of the arterioles, which can enlarge their size after hepatectomy. In clinical studies, the resistance to pulsatile arterial flow caused by the microvascular bed can be reflected by the resistive index (RI), a frequently used index in assessing arterial resistance. This study uses the RI in a novel manner to conveniently obtain the postoperative outflow impedance from the preoperative impedance. The major emphasis of this study is to devise a model to capture the postoperative hepatic hemodynamics after left hepatectomy. To study this, we build a hepatic network model and analyze its behavior under four different outflow impedance: (a) the same as preoperative impedance; (b) evaluated using the RI and preoperative impedance; (c) computed from structured tree BC with increased radius of terminal vessels; and (d) evaluated using structured tree with both increased radius of root vessel, ie, the outlets of the postoperative hepatic artery, and increased radius of terminal vessels. Our results show that both impedance from (b) and (d) give a physiologically reasonable postoperative hepatic pressure range, while the RI in (b) allows for a fast approximation of postoperative impedance. Since hemodynamics after hepatectomy are not fully understood, the methods used in this study to explore postoperative outflow BC are informative for future models exploring hemodynamic effects of partial hepatectomy.

A Systematic Review of Three-Dimensional Printing in Liver Disease

The purpose of this review is to analyse current literature related to the clinical applications of 3D printed models in liver disease. A search of the literature was conducted to source studies from databases with the aim of determining the applications and feasibility of 3D printed models in liver disease. 3D printed model accuracy and costs associated with 3D printing, the ability to replicate anatomical structures and delineate important characteristics of hepatic tumours, and the potential for 3D printed liver models to guide surgical planning are analysed. Nineteen studies met the selection criteria for inclusion in the analysis. Seventeen of them were case reports and two were original studies. Quantitative assessment measuring the accuracy of 3D printed liver models was analysed in five studies with mean difference between 3D printed models and original source images ranging from 0.2 to 20%. Fifteen studies provided qualitative assessment with results showing the usefulness of 3D printed models when used as clinical tools in preoperative planning, simulation of surgical or interventional procedures, medical education, and training. The cost and time associated with 3D printed liver model production was reported in 11 studies, with costs ranging from US$13 to US$2000, duration of production up to 100 h. This systematic review shows that 3D printed liver models demonstrate hepatic anatomy and tumours with high accuracy. The models can assist with preoperative planning and may be used in the simulation of surgical procedures for the treatment of malignant hepatic tumours.

Role of innovative 3D printing models in the management of hepatobiliary malignancies

Three-dimensional (3D) printing has recently emerged as a new technique in various liver-related surgical fields. There are currently only a few systematic reviews that summarize the evidence of its impact. In order to construct a systematic literature review of the applications and effects of 3D printing in liver surgery, we searched the PubMed, Embase and ScienceDirect databases for relevant titles, according to the PRISMA statement guidelines. We retrieved 162 titles, of which 32 met the inclusion criteria and are reported. The leading application of 3D printing in liver surgery is for preoperative planning. 3D printing techniques seem to be beneficial for preoperative planning and educational tools, despite their cost and time requirements, but this conclusion must be confirmed by additional randomized controlled trials.

Impact of three-dimensional visualization technology on surgical strategies in complex hepatic cancer

Surgical resection is still the mainstay of treatment for primary liver cancer (PLC). It is unclear whether three-dimensional visualization (3DV) preoperative evaluation and simulated liver resection would affect the surgical strategies and improve the R0 resection rates of patients with complex PLC when compared with the 2D evaluation using computed tomography or magnetic resonance imaging. In the study, patients with complex PLC who were subjected to laparotomy underwent both 2D and 3DV evaluation before operation. A comparison between the 2D and 3DV evaluation was compared with the gold standard of laparotomy findings. In this study, of 335 patients with complex PLC, 71 were assessed to have resectable tumors. 2D and 3DV assessments determined 63 and 71 patients to have resectable PLC, respectively. At laparotomy 69 of the 71 patients were found to have resectable PLC, but 2 patients were found to be unresectable because of detection of metastatic lesions on laparotomy, which were not detected either by 2D or 3DV preoperative evaluation. The accuracy, false positive and false negative rates of the 2D and the 3DV preoperative assessments in determining tumor resectability were 85.9%, 2.8%, 11.3%, and 97.2% (p < 0.05), 2.8%, 0%, respectively. The 3DV and 2D preoperative evaluation revealed 17 and 13 patients with vascular anomalies, respectively. There were 4 patients with major vascular anomalies not detected by 2D evaluation, whose surgical strategies were modified by 3DV evaluation. These results suggested 3DV preoperative assessment could lead to better in evaluating tumor resectability, with potential benefit in the modification of surgical strategy for patients with complex PLC.

Digital and intelligent liver surgery in the new era: Prospects and dilemmas

Despite tremendous advances in traditional imaging technology over the past few decades, the intraoperative identification of lesions is still based on naked eye observation or pre-operative image evaluation. However, these two-dimensional image data cannot objectively reflect the complex anatomical structure of the liver and the detailed morphological features of the lesion, which directly limits the clinical application value of these imaging data in surgery in that it cannot improve the curative efficacy of surgery and the prognosis of the patient. This traditional mode of diagnosis and treatment has been changed by digital medical imaging technology in the new era with its significant function of accurate and efficient diagnosis of diseases, selection of reasonable treatment schemes, improvement of radical resection rate and reduction of surgical risk. In this paper, we reviewed the latest application of digital intelligent diagnosis and treatment technology related to liver surgery in the hope that it may help to achieve accurate treatment of liver surgery diseases.

Application of 3D visualization and 3D printing technology on ERCP for patients with hilar cholangiocarcinoma

Endoscopic retrograde cholangiopancreatography (ERCP) is an important treatment for inoperable hilar cholangiocarcinoma (HCC). The aim of the present study as to evaluate the clinical value of three-dimensional visualization (3DV) and 3D printing (3DP) technologies for ERCP in patients with HCC. The clinical data of 15 patients with HCC admitted for ERCP were analyzed retrospectively, including 9 males and 6 females. Thin-sliced data of computed tomography and magnetic resonance cholangiopancreatography (MRCP) were acquired and imported into Mimics Innovation Suite v17.0 software for 3D reconstruction. Standard Template Library files were exported for 3D printing. The target bile duct and Bismuth-Corlette (BC) classification were selected and performed respectively with the aid of Mimics Innovation Suite v17.0 software. The results were compared with the selected ones in ERCP. 3DV and 3DP models were successfully constructed for all patients, which presented the tumor, bile duct and the spatial relationship between them from multiple perspectives. The ERCP of all patients in the present study were performed successfully. The target bile duct screened by them had a high concordance rate of 86.7% with that in ERCP. The diagnostic accuracy of BC type results by 3DV and 3DP models was 93.3%. 3DV and 3DP technologies can accurately show the tumor and its associations with the surrounding bile duct, and it can be used to guide ERCP in HCC patients and improve the success rate of the operation.

Image once, print thrice? Three-dimensional printing of replacement parts

OBJECTIVE

The last 20 years has seen an exponential increase in 3D printing as it pertains to the medical industry and more specifically surgery. Previous reviews in this domain have chosen to focus on applications within a specific field. To our knowledge, none have evaluated the broad applications of patient-specific or digital imaging and communications in medicine (DICOM) derived applications of this technology.

METHODS

We searched PUBMED and CINAHL from April 2012 to April 2017.

RESULTS

261 studies fulfilled the inclusion criteria. Proportions of articles reviewed: DICOM (5%), CT (38%), MRI (20%), Ultrasonography (28%), and Bio-printing (9%).

CONCLUSION

There is level IV evidence to support the use of 3D printing for education, pre-operative planning, simulation and implantation. In order to make this technology widely applicable, it will require automation of DICOM to standard tessellation language to implant. Advances in knowledge: Recent lapses in intellectual property and greater familiarity with rapid prototyping in medicine has set the stage for the next generation of custom implants, simulators and autografts. Radiologists may be able to help establish reimbursable procedural terminology.

Extended left hepatectomy for intrahepatic cholangiocarcinoma: hepatic vein reconstruction with in-situ hypothermic perfusion and extracorporeal membrane oxygenation

BACKGROUND

Liver resection for intrahepatic cholangiocarcinoma (ICC) with invasion of the inferior vena cava (IVC) and hepatic veins (HV) is a challenging procedure.

CASE PRESENTATION

We report a case of a 63-year-old woman with a 6-cm, centrally located liver mass. Her biochemistry results were normal except for a Ca19-9 level of 1199 U/ml. The liver biopsy was consistent with ICC and 60% macrosteatosis. Abdominal CT scans revealed a large central mass invading the left HV, middle HV and right HV, infringing on their junction with the vena cava. An operation was planned using a 3-dimensional (3D) computer simulation model using dedicated software. We also describe a novel veno-portal-venous extracorporeal membrane oxygenation (VPV-ECMO) support with in-situ hypothermic perfusion (IHP) during this procedure. We aimed to perform an extended left hepatectomy and reconstruct 3 right HV orifices with an interposition jump graft to the IVC with total vascular exclusion (TVE) and IHP A supplemental video describing the preoperative planning, the operative procedure with the postoperative follow-up in detail is presented. After the patient was discharged, she developed a hepatic venous outflow obstruction 3 months postoperatively, which was effectively managed with hepatic venous stenting by interventional radiology. She is currently symptom free and without tumour recurrence at the 1-year follow-up.

CONCLUSIONS

This report demonstrates that extended left hepatectomy for IHC with IHP and VPV-ECMO is safe and feasible under the supervision of a highly experienced team.

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.