A Systematic Review of Three-Dimensional Printing in Liver Disease

A novel 3D-printed educational model for the training of laparoscopic bile duct Exploration:a pilot study for beginning trainees

Background

Laparoscopic common bile duct exploration (LCBDE) is a minimally invasive procedure for the removal of bile duct stones that is often performed by experienced hepatobiliary surgeons; beginners do not easily master this approach.

Aim

To investigate the effectiveness and practicality of a three-dimensional printed (3DP) anatomical model based on radiographic images in the training of LCBDE techniques and formulate standardized educational workflows.

Methods

Colored LCBDE training models were produced using 3DP technology. Twenty standardized training trainees were randomly divided into two groups: a 3DP model training group and a traditional laparoscopic simulation training group. Both groups received the same number of teaching hours. After a 4-weeks training course, the trainees' subjective and objective progress in basic knowledge and manipulations were evaluated and compared.

Results

Compared with traditional laparoscopic simulation, 3DP model simulation training is of great significance in improving trainers' understanding of surgical procedures and cooperation during the operation. Trainees with 3DP models training demonstrated a significant improvement in their understanding of the key points of surgery (χ2 = 6.139, p = 0.013) and skills scores, especially in core procedural steps operation. More importantly, the trainees showed higher levels of satisfaction and self-confidence while assisting in the surgery.

Conclusion

With the development of 3DP models, improvements in the learning effect for theoretical understanding and practical skills were significant. The present study is the initial educational experience with 3DP models to facilitate the operational capabilities of the trainees for LCBDE.

Training the Next Generation of Transplant Surgeons With a 3-Dimensional Trainer: A Pilot Study

Background

In the United States, no published guidelines promote exposure to technical variants (ie, living donor or split liver) during transplant fellowship. Simulation with hands-on liver models may improve training in transplantation. This pilot study addressed 3 overall goals (material and model creation tools, recruitment rates and assessment of workload, and protocol adherence).

Methods

A patient-specific hands-on liver model was constructed from clinical imaging, and it needed to be resilient and realistic. Multiple types of materials were tested between January 2020 and August 2022. Participants were recruited stepwise. A left lateral segmentectomy simulation was conducted between August 2022 and December 2022 to assess protocol adherence.

Results

Digital anatomy 3-dimensional printing was considered the best option for the hands-on liver model. The recruitment rate was 100% and 47% for junior attendings and surgical residents, respectively. Ten participants were included and completed all the required surveys. Seven (70%) and 6 (60%) participants "agreed" that the overall quality of the model and the material were acceptable for surgical simulation. Five participants (50%) "agreed" that the training improved their surgical skills. Nine participants (90%) "strongly agreed" that similar sessions should be included in surgical training programs.

Conclusions

Three-dimensional hands-on liver models have the advantage of tactile feedback and were rated favorably as a potential training tool. Study enrollment for further studies is possible with the support of leadership. Rigorous multicenter designs should be developed to measure the actual impact of 3-dimensional hands-on liver models on surgical training.

Cardiovascular computed tomography in cardiovascular disease: An overview of its applications from diagnosis to prediction

Cardiovascular computed tomography angiography (CTA) is a widely used imaging modality in the diagnosis of cardiovascular disease. Advancements in CT imaging technology have further advanced its applications from high diagnostic value to minimising radiation exposure to patients. In addition to the standard application of assessing vascular lumen changes, CTA-derived applications including 3D printed personalised models, 3D visualisations such as virtual endoscopy, virtual reality, augmented reality and mixed reality, as well as CT-derived hemodynamic flow analysis and fractional flow reserve (FFRCT) greatly enhance the diagnostic performance of CTA in cardiovascular disease. The widespread application of artificial intelligence in medicine also significantly contributes to the clinical value of CTA in cardiovascular disease. Clinical value of CTA has extended from the initial diagnosis to identification of vulnerable lesions, and prediction of disease extent, hence improving patient care and management. In this review article, as an active researcher in cardiovascular imaging for more than 20 years, I will provide an overview of cardiovascular CTA in cardiovascular disease. It is expected that this review will provide readers with an update of CTA applications, from the initial lumen assessment to recent developments utilising latest novel imaging and visualisation technologies. It will serve as a useful resource for researchers and clinicians to judiciously use the cardiovascular CT in clinical practice.

Preoperative and postoperative 3D reconstruction for surgical management of a post-cholecystectomy biliary stricture

Cholecystectomy-related iatrogenic biliary injuries cause intricate postoperative complications that can significantly affect a patient's life, often leading to chronic liver disease and biliary stenosis. These patients require a multidisciplinary approach with intervention from radiologists, endoscopists and surgeons experienced in hepatobiliary reconstruction. Symptoms vary from none to jaundice, pruritus and ascending cholangitis. The best strategy for the management of biliary stricture is based on optimal preoperative planning. Our patient presented 1 year after an iatrogenic lesion was induced during a cholecystectomy, and was managed with a complex common bile duct reconstruction through a Roux-en-Y hepaticojejunostomy. The three-dimensional (3D) model reconstruction of the biliary tract was pivotal in the planning of the patient's surgery, providing additional preoperative and intraoperative assistance throughout the procedure. The 3D model's description of detailed spatial relations between the bile duct and the vascular structure in the liver hilum enabled a correct surgical dissection and safe execution of the anastomosis.

3D printing of self-healing personalized liver models for surgical training and preoperative planning

3D printing can produce intuitive, precise, and personalized anatomical models, providing invaluable support for precision medicine, particularly in areas like surgical training and preoperative planning. However, conventional 3D printed models are often significantly more rigid than human organs and cannot undergo repetitive resection, which severely restricts their clinical value. Here we report the stereolithographic 3D printing of personalized liver models based on physically crosslinked self-healing elastomers with liver-like softness. Benefiting from the short printing time, the highly individualized models can be fabricated immediately following enhanced CT examination. Leveraging the high-efficiency self-healing performance, these models support repetitive resection for optimal trace through a trial-and-error approach. At the preliminary explorative clinical trial (NCT06006338), a total of 5 participants are included for preoperative planning. The primary outcomes indicate that the negative surgery margins are achieved and the unforeseen injuries of vital vascular structures are avoided. The 3D printing of liver models can enhance the safety of hepatic surgery, demonstrating promising application value in clinical practice.

Hepatobiliary surgery based on intelligent image segmentation technology

Liver disease is an important disease that seriously threatens human health. It accounts for the highest proportion in various malignant tumors, and its incidence rate and mortality are on the rise, seriously affecting human health. Modern imaging has developed rapidly, but the application of image segmentation in liver tumor surgery is still rare. The application of image processing technology represented by artificial intelligence (AI) in surgery can greatly improve the efficiency of surgery, reduce surgical complications, and reduce the cost of surgery. Hepatocellular carcinoma is the most common malignant tumor in the world, and its mortality is second only to lung cancer. The resection rate of liver cancer surgery is high, and it is a multidisciplinary surgery, so it is necessary to explore the possibility of effective switching between different disciplines. Resection of hepatobiliary and pancreatic tumors is one of the most challenging and lethal surgical procedures. The operation requires a high level of doctors' experience and understanding of anatomical structures. The surgical segmentation is slow and there may be obvious complications. Therefore, the surgical system needs to make full use of the relevant functions of AI technology and computer vision analysis software, and combine the processing strategy based on image processing algorithm and computer vision analysis model. Intelligent optimization algorithm, also known as modern heuristic algorithm, is an algorithm with global optimization performance, strong universality, and suitable for parallel processing. This algorithm generally has a strict theoretical basis, rather than relying solely on expert experience. In theory, the optimal solution or approximate optimal solution can be found in a certain time. This work studies the hepatobiliary surgery through intelligent image segmentation technology, and analyzes them through intelligent optimization algorithm. The research results showed that when other conditions were the same, there were three patients who had adverse reactions in hepatobiliary surgery through intelligent image segmentation technology, accounting for 10%. The number of patients with adverse reactions in hepatobiliary surgery by conventional methods was nine, accounting for 30%, which was significantly higher than the former, indicating a positive relationship between intelligent image segmentation technology and hepatobiliary surgery.

Full-sized realistic 3D printed models of liver and tumour anatomy: a useful tool for the clinical medicine education of beginning trainees

BACKGROUND

Simulation-based medical education (SBME) and three-dimensional printed (3DP) models are increasingly used in continuing medical education and clinical training. However, our understanding of their role and value in improving trainees' understanding of the anatomical and surgical procedures associated with liver surgery remains limited. Furthermore, gender bias is also a potential factor in the evaluation of medical education. Therefore, the aim of this study was to evaluate the educational benefits trainees receive from the use of novel 3DP liver models while considering trainees' experience and gender.

METHODS

Full-sized 3DP liver models were developed and printed using transparent material based on anonymous CT scans. We used printed 3D models and conventional 2D CT scans of the liver to investigate thirty trainees with various levels of experience and different genders in the context of both small group teaching and formative assessment. We adopted a mixed methods approach involving both questionnaires and focus groups to collect the views of different trainees and monitors to assess trainees' educational benefits and perceptions after progressing through different training programs. We used Objective Structured Clinical Examination (OSCE) and Likert scales to support thematic analysis of the responses to the questionnaires by trainees and monitors, respectively. Descriptive analyses were conducted using SPSS statistical software version 21.0.

RESULTS

Overall, a 3DP model of the liver is of great significance for improving trainees' understanding of surgical procedures and cooperation during operation. After viewing the personalized full-sized 3DP liver model, all trainees at the various levels exhibited significant improvements in their understanding of the key points of surgery (p < 0.05), especially regarding the planned surgical procedure and key details of the surgical procedures. More importantly, the trainees exhibited higher levels of satisfaction and self-confidence during the operation regardless of gender. However, with regard to gender, the results showed that the improvement of male trainees after training with the 3DP liver model was more significant than that of female trainees in understanding and cooperation during the surgical procedure, while no such trend was found with regard to their understanding of the base knowledge.

CONCLUSION

Trainees and monitors agreed that the use of 3DP liver models was acceptable. The improvement of the learning effect for practical skills and theoretical understanding after training with the 3DP liver models was significant. This study also indicated that training with personalized 3DP liver models can improve all trainees' presurgical understanding of liver tumours and surgery and males show more advantage in understanding and cooperation during the surgical procedure as compared to females. Full-sized realistic 3DP models of the liver are an effective auxiliary teaching tool for SBME teaching in Chinese continuing medical education.

Patient-Specific 3D Printed Soft Models for Liver Surgical Planning and Hands-On Training

Background: Pre-surgical simulation-based training with three-dimensional (3D) models has been intensively developed in complex surgeries in recent years. This is also the case in liver surgery, although with fewer reported examples. The simulation-based training with 3D models represents an alternative to current surgical simulation methods based on animal or ex vivo models or virtual reality (VR), showing reported advantages, which makes the development of realistic 3D-printed models an option. This work presents an innovative, low-cost approach for producing patient-specific 3D anatomical models for hands-on simulation and training. Methods: The article reports three paediatric cases presenting complex liver tumours that were transferred to a major paediatric referral centre for treatment: hepatoblastoma, hepatic hamartoma and biliary tract rhabdomyosarcoma. The complete process of the additively manufactured liver tumour simulators is described, and the different steps for the correct development of each case are explained: (1) medical image acquisition; (2) segmentation; (3) 3D printing; (4) quality control/validation; and (5) cost. A digital workflow for liver cancer surgical planning is proposed. Results: Three hepatic surgeries were planned, with 3D simulators built using 3D printing and silicone moulding techniques. The 3D physical models showed highly accurate replications of the actual condition. Additionally, they proved to be more cost-effective in comparison with other models. Conclusions: It is demonstrated that it is possible to manufacture accurate and cost-effective 3D-printed soft surgical planning simulators for treating liver cancer. The 3D models allowed for proper pre-surgical planning and simulation training in the three cases reported, making it a valuable aid for surgeons.

Patient-Specific 3D-Printed Low-Cost Models in Medical Education and Clinical Practice

3D printing has been increasingly used for medical applications with studies reporting its value, ranging from medical education to pre-surgical planning and simulation, assisting doctor-patient communication or communication with clinicians, and the development of optimal computed tomography (CT) imaging protocols. This article presents our experience of utilising a 3D-printing facility to print a range of patient-specific low-cost models for medical applications. These models include personalized models in cardiovascular disease (from congenital heart disease to aortic aneurysm, aortic dissection and coronary artery disease) and tumours (lung cancer, pancreatic cancer and biliary disease) based on CT data. Furthermore, we designed and developed novel 3D-printed models, including a 3D-printed breast model for the simulation of breast cancer magnetic resonance imaging (MRI), and calcified coronary plaques for the simulation of extensive calcifications in the coronary arteries. Most of these 3D-printed models were scanned with CT (except for the breast model which was scanned using MRI) for investigation of their educational and clinical value, with promising results achieved. The models were confirmed to be highly accurate in replicating both anatomy and pathology in different body regions with affordable costs. Our experience of producing low-cost and affordable 3D-printed models highlights the feasibility of utilizing 3D-printing technology in medical education and clinical practice.

Hyper accuracy three-dimensional (HA3D™) technology for planning complex liver resections: a preliminary single center experience

Three-dimensional visualization technology (3DVT) has been recently introduced to achieve a precise preoperative planning of liver surgery. The aim of this observational study was to assess the accuracy of 3DVT for complex liver resections. 3DVT with hyper accuracy three-dimensional (HA3D™) technology was introduced at our institution on February 2020. Anatomical characteristics were collected from two-dimensional imaging (2DI) and 3DVT, while intraoperative and postoperative outcomes were recorded prospectively. A total of 62 patients were enrolled into the study. 3DVT was able to study tumor extension and liver anatomy, identifying at least one vascular variation in 37 patients (59.7%). Future remnant liver volume (FRLV) was measured using 2DI and 3DVT. The paired samples t test assessed positive correlation between the two methods (p < 0.001). At least one vessel was suspected to be invaded by the tumor in 8 (15.7%) 2DI cases vs 16 (31.4%) 3DVT cases, respectively. During surgery, vascular invasion was detected in 17 patients (33.3%). A total of 73 surgical procedures were proposed basing on 2DI, including 2 alternatives for 16 patients. After 3DVT, the previously planned procedure was changed in 15 cases (29.4%), due to the clearer information provided. A total of 51 patients (82%) underwent surgery. The most frequent procedure was right hepatectomy (33.3%), followed by left hepatectomy (23.5%) and left trisectionectomy (13.7%). Vascular resection and reconstruction were performed in 10 patients (19.6%) and portal vein was resected in more than half of these cases (66.7%). 3DVT leads to a more detailed and tailored approach to complex liver surgery, improving surgeons' knowledge of liver anatomy and accuracy of liver resection.

3D Printed Models in Cardiovascular Disease: An Exciting Future to Deliver Personalized Medicine

3D printing has shown great promise in medical applications with increased reports in the literature. Patient-specific 3D printed heart and vascular models replicate normal anatomy and pathology with high accuracy and demonstrate superior advantages over the standard image visualizations for improving understanding of complex cardiovascular structures, providing guidance for surgical planning and simulation of interventional procedures, as well as enhancing doctor-to-patient communication. 3D printed models can also be used to optimize CT scanning protocols for radiation dose reduction. This review article provides an overview of the current status of using 3D printing technology in cardiovascular disease. Limitations and barriers to applying 3D printing in clinical practice are emphasized while future directions are highlighted.

Three-dimensional modeling in complex liver surgery and liver transplantation

Liver resection and transplantation are the most effective therapies for many hepatobiliary tumors and diseases. However, these surgical procedures are challenging due to the anatomic complexity and many anatomical variations of the vascular and biliary structures. Three-dimensional (3D) printing models can clearly locate and describe blood vessels, bile ducts and tumors, calculate both liver and residual liver volumes, and finally predict the functional status of the liver after resection surgery. The 3D printing models may be particularly helpful in the preoperative evaluation and surgical planning of especially complex liver resection and transplantation, allowing to possibly increase resectability rates and reduce postoperative complications. With the continuous developments of imaging techniques, such models are expected to become widely applied in clinical practice.

Anatomical Engineering and 3D Printing for Surgery and Medical Devices: International Review and Future Exponential Innovations

Three-dimensional printing (3DP) has recently gained importance in the medical industry, especially in surgical specialties. It uses different techniques and materials based on patients' needs, which allows bioprofessionals to design and develop unique pieces using medical imaging provided by computed tomography (CT) and magnetic resonance imaging (MRI). Therefore, the Department of Biology and Medicine and the Department of Physics and Engineering, at the Bioastronautics and Space Mechatronics Research Group, have managed and supervised an international cooperation study, in order to present a general review of the innovative surgical applications, focused on anatomical systems, such as the nervous and craniofacial system, cardiovascular system, digestive system, genitourinary system, and musculoskeletal system. Finally, the integration with augmented, mixed, virtual reality is analyzed to show the advantages of personalized treatments, taking into account the improvements for preoperative, intraoperative planning, and medical training. Also, this article explores the creation of devices and tools for space surgery to get better outcomes under changing gravity conditions.

The current and possible future role of 3D modelling within oesophagogastric surgery: a scoping review

BACKGROUND

3D reconstruction technology could revolutionise medicine. Within surgery, 3D reconstruction has a growing role in operative planning and procedures, surgical education and training as well as patient engagement. Whilst virtual and 3D printed models are already used in many surgical specialities, oesophagogastric surgery has been slow in their adoption. Therefore, the authors undertook a scoping review to clarify the current and future roles of 3D modelling in oesophagogastric surgery, highlighting gaps in the literature and implications for future research.

METHODS

A scoping review protocol was developed using a comprehensive search strategy based on internationally accepted guidelines and tailored for key databases (MEDLINE, Embase, Elsevier Scopus and ISI Web of Science). This is available through the Open Science Framework (osf.io/ta789) and was published in a peer-reviewed journal. Included studies underwent screening and full text review before inclusion. A thematic analysis was performed using pre-determined overarching themes: (i) surgical training and education, (ii) patient education and engagement, and (iii) operative planning and surgical practice. Where applicable, subthemes were generated.

RESULTS

A total of 56 papers were included. Most research was low-grade with 88% (n = 49) of publications at or below level III evidence. No randomised control trials or systematic reviews were found. Most literature (86%, n = 48) explored 3D reconstruction within operative planning. These were divided into subthemes of pre-operative (77%, n = 43) and intra-operative guidance (9%, n = 5). Few papers reported on surgical training and education (14%, n = 8), and were evenly subcategorised into virtual reality simulation (7%, n = 4) and anatomical teaching (7%, n = 4). No studies utilising 3D modelling for patient engagement and education were found.

CONCLUSION

The use of 3D reconstruction is in its infancy in oesophagogastric surgery. The quality of evidence is low and key themes, such as patient engagement and education, remain unexplored. Without high quality research evaluating the application and benefits of 3D modelling, oesophagogastric surgery may be left behind.

Validation of a three-dimensional printed dry lab pancreaticojejunostomy model in surgical assessment: a cross-sectional study

OBJECTIVES

Until now, there have been few tools to evaluate whether a surgeon was technically ready to perform a safe pancreaticojejunostomy (PJ). In the current study, we aimed to evaluate whether a three-dimensional model could mimic a real surgical situation and distinguish between surgeons of different levels of experiences.

DESIGN

A three-dimensional PJ dry laboratory model was printed. Eight experienced pancreatic surgeons were tasked to evaluate the appearance and tactile sensation of the model. Proficiency was scored based on 15 surgeons with various levels of pancreatic experience performing a PJ on the three-dimensional model. Additionally, the time of manipulation and NASA Task Load Index (NASA-TLX) scores were recorded for each operation.

SETTING

Our study was conducted in multimedical centre in China.

RESULTS

Compared with real surgical situations, this model had similar appearance (3.96±0.55 out of five points) and tactile sensation (3.85±0.46 out of five points) according to the expert evaluation. Additionally, the chief surgeon group scored the best in proficiency (based on NASA-TLX scores and operative time), and there were statistical differences for performances among surgeons of various levels (p<0.05).

CONCLUSION

The three-dimensional PJ model could mimic a real surgical situation and can distinguish between surgeons of different levels of experiences.

Application of a 3D-printed eye model for teaching direct ophthalmoscopy to undergraduates

PURPOSE

This study aims to design an eye model that can simulate the fundus for teaching direct ophthalmoscopy and to evaluate its effectiveness.

METHODS

We first used 3D printing materials to make an eye model and then randomly assigned 92 undergraduates into group A (model-assisted training group) and group B (traditional training group) to test our model. After the same training time, real patients were used to test the students, with 120 s as the examination time limit. We recorded the students' ability to clearly see the optic disk, the time to determine the cup-to-disk ratio, and whether they were correct.

RESULTS

Forty-three students in group A (93.48%) successfully saw the fundus, while 21 in group B (45.65%) succeeded. The difference between the two groups was 47.83% (95% confidence interval, 29.59-66.07%, P < 0.0001). The median time to see the fundus was 29s (95% confidence interval 23-45 s) in group A, while an estimated minimum time in group B was 80 s, indicating that group A was significantly faster than group B (P < 0.0001).

CONCLUSIONS

This 3D-printed eye model significantly improved the students' study interest, study efficiency, and study results and is worthy of being promoted.

Dealing with hepatic artery traumas: A clinical literature review

BACKGROUND

The hepatic artery (HA) is one of the most threatened vascular structures during hepatopancreatobiliary (HPB) surgeries and interventional procedures. It can be affected by many clinical pictures, especially tumors, due to its anatomical position and neighborhood.

AIM

To reveal the evolution and recent developments in the management of HA traumas in the light of the literature.

METHODS

In this article, 100 years of MEDLINE (PubMed) literature and articles including cases and series of HA injuries were reviewed, and the types of injury occurrence, treatment, and related complications and their management were compiled.

RESULTS

The risk of HA injury increases during cholecystectomies and pancreatoduodenectomies, among the most common operations. HA anatomy shows anomalies in approximately 15%-25% of the cases, further increasing this risk. The incidence of HA injury is not precisely known. Approaches that have evolved in recent years in managing patients with HA injury (laceration, transection, ligation, resection) with severe morbidity and mortality risk are reviewed in light of the current literature.

CONCLUSION

In conclusion, complications and deaths due to HA injury are less common today. The risk of complications increases in patients with hemodynamic instability, jaundice, cholangitis, and sepsis. Revealing the variations in the preoperative radiological evaluation will reduce the risks. In cases where HA injury is detected, arterial flow continuity should be tried to maintain with primary anastomosis, arterial transpositions, or grafts. In cases where bile duct injury develops, patients should be directed to HPB surgery centers, considering the possibility of accompanying HA injury. Large-scale and multicentric studies are needed to understand better the early and long-term results of HA ligation and determine preventive procedures.

Hybrid Additive Fabrication of a Transparent Liver with Biosimilar Haptic Response for Preoperative Planning

Due to the complexity of liver surgery, the interest in 3D printing is constantly increasing among hepatobiliary surgeons. The aim of this study was to produce a patient-specific transparent life-sized liver model with tissue-like haptic properties by combining additive manufacturing and 3D moulding. A multistep pipeline was adopted to obtain accurate 3D printable models. Semiautomatic segmentation and registration of routine medical imaging using 3D Slicer software allowed to obtain digital objects representing the structures of interest (liver parenchyma, vasculo-biliary branching, and intrahepatic lesion). The virtual models were used as the source data for a hybrid fabrication process based on additive manufacturing using soft resins and casting of tissue-mimicking silicone-based blend into 3D moulds. The model of the haptic liver reproduced with high fidelity the vasculo-biliary branching and the relationship with the intrahepatic lesion embedded into the transparent parenchyma. It offered high-quality haptic perception and a remarkable degree of surgical and anatomical information. Our 3D transparent model with haptic properties can help surgeons understand the spatial changes of intrahepatic structures during surgical manoeuvres, optimising preoperative surgical planning.

Using 3D-Printed Mesh-Like Brain Cortex with Deep Structures for Planning Intracranial EEG Electrode Placement

Surgical evaluation of medically refractory epilepsy frequently necessitates implantation of multiple intracranial electrodes for the identification of the seizure focus. Knowledge of the individual brain's surface anatomy and deep structures is crucial for planning the electrode implantation. We present a novel method of 3D printing a brain that allows for the simulation of placement of all types of intracranial electrodes. We used a DICOM dataset of a T1-weighted 3D-FSPGR brain MRI from one subject. The segmentation tools of Materialise Mimics 21.0 were used to remove the osseous anatomy from brain parenchyma. Materialise 3-matic 13.0 was then utilized in order to transform the cortex of the segmented brain parenchyma into a mesh-like surface. Using 3-matic tools, the model was modified to incorporate deep brain structures and create an opening in the medial aspect. The final model was then 3D printed as a cerebral hemisphere with nylon material using selective laser sintering technology. The final model was light and durable and reflected accurate details of the surface anatomy and some deep structures. Additionally, standard surgical depth electrodes could be passed through the model to reach deep structures without damaging the model. This novel 3D-printed brain model provides a unique combination of visualizing both the surface anatomy and deep structures through the mesh-like surface while allowing repeated needle insertions. This relatively low-cost technique can be implemented for interdisciplinary preprocedural planning in patients requiring intracranial EEG monitoring and for any intervention that requires needle insertion into a solid organ with unique anatomy and internal targets.

The evolution of surgery for colorectal liver metastases: A persistent challenge to improve survival

Only a few decades ago, the opinion that colorectal liver metastases were a palliative diagnosis changed. In fact, previously, the prevailing view was strongly resistant against resecting colorectal liver metastases. Constant technical improvement of liver surgery and, much later, effective chemotherapy allowed for a successful wider application of surgery. The clinical use of portal vein embolization was the starting signal of regenerative liver surgery, where insufficient liver volume can be expanded to an extent where safe resection is possible. Today, a number of these techniques including portal vein ligation, associating liver partition and portal vein ligation for staged hepatectomy, and bi-embolization (portal and hepatic vein) can be successfully used to address an insufficient future liver remnant in staged resections. It turned out that the road to success is embedding surgery in a well-orchestrated oncological concept of controlling systemic disease. This concept was the prerequisite that meant liver transplantation could enter the treatment strategy for colorectal liver metastases, ending up with a 5-year overall survival of 80% in highly selected cases. In particular, techniques combining principles of 2-stage hepatectomy and liver transplantation, such as "resection and partial liver segment 2-3 transplantation with delayed total hepatectomy" (RAPID) are on the rise. These techniques enable the use of partial liver grafts with primarily insufficient liver volume. All this progress also prompted a number of innovative local therapies to address recurrences ultimately transferring colorectal liver metastases from instantly deadly into a chronic disease in some cases.

A study of three-dimensional reconstruction and printing models in two cases of soft tissue sarcoma of the thigh

PURPOSE

The aim of our study was to demonstrate the value of three-dimensional (3D) reconstruction and three-dimensional printing (3DP) models in two cases of soft tissue sarcoma (STS) of the thigh.

MATERIALS AND METHODS

Two patients with STS were recruited and underwent enhanced CT and MRI scans. Then, the 3D models were reconstructed and printed using the obtained data, and five experts were invited to assess the segmentation quality. In addition, 34 junior, intermediate and senior general surgeons were recruited to demonstrate the value of 3D models in preoperative planning and invited five surgeons to complete the assessment of 3D models-assisted intraoperative navigation. Finally, 32 interns were enrolled to explore the significance of 3D models in medical education.

RESULTS

All experts agree with the accuracy of the 3D models. The application of 3D models in preoperative planning improved the understanding of general surgeons (P = 0.000, P = 0.000, P = 0.000). After the planning tools were exchanged between the two groups, senior surgeons in group A showed more significant improvements in performance than junior and intermediate surgeons in group A (P = 0.001, P = 0.006). Surgeons unanimously agree on the value of 3D models in intraoperative navigation. When applied for the education of medical interns, these models could enhance their understanding of pathologic anatomies (P = 0.036).

CONCLUSION

In two operations for STS of the thigh with complex adjacencies, our study demonstrates that 3D models are of great value for preoperative planning, intraoperative navigation and medical education. More importantly, these models were more helpful to senior general surgeons.

Utility of a 3-dimensionally printed color-coded bone model to visualize impinging osteophytes for arthroscopic débridement arthroplasty in elbow osteoarthritis

BACKGROUND

The identification and precise removal of bony impingement lesions during arthroscopic débridement arthroplasty for elbow osteoarthritis require a high level of experience and surgical skill. We have developed a new technique to identify impinging osteophytes on a computer display by simulating elbow motion using the multiple positions of 3-dimensional (3D) elbow models created from computed tomography data. Moreover, an actual color-coded 3D model indicating the impinging osteophytes was created with a 3D printer and was used as an intraoperative reference tool. This study aimed to verify the efficacy of these new technologies in arthroscopic débridement for elbow osteoarthritis.

METHODS

We retrospectively studied 16 patients treated with arthroscopic débridement for elbow osteoarthritis after a preoperative computer simulation. Patients who underwent surgery with only the preoperative simulation were assigned to group 1 (n = 8), whereas those on whom we operated using a color-coded 3D bone model created from the preoperative simulation were assigned to group 2 (n = 8). Elbow extension and flexion range of motion (ROM), the Mayo Elbow Performance Score (MEPS), and the severity of osteoarthritis were compared between the groups.

RESULTS

Although preoperative elbow flexion and MEPS values were not significantly different between the groups, preoperative extension was significantly more restricted in group 2 than in group 1 (P = .0131). Group 2 tended to include more severe cases according to the Hastings-Rettig classification (P = .0693). ROM and MEPS values were improved in all cases. No significant differences in postoperative ROM or MEPS values were observed between the groups. There were no significant differences in the improvement in ROM or MEPS values between the 2 groups.

CONCLUSIONS

The use of preoperative simulation and a color-coded bone model could help to achieve as good postoperative ROM and MEPS values for advanced elbow osteoarthritis as those for early and intermediate stages.

Applicability of 3D-printed models in hepatobiliary surgey: results from "LIV3DPRINT" multicenter study

BACKGROUND

Hepatobiliary resections are challenging due to the complex liver anatomy. Three-dimensional printing (3DP) has gained popularity due to its ability to produce anatomical models based on the characteristics of each patient.

METHODS

A multicenter study was conducted on complex hepatobiliary tumours. The endpoint was to validate 3DP model accuracy from original image sources for application in the teaching, patient-communication, and planning of hepatobiliary surgery.

RESULTS

Thirty-five patients from eight centers were included. Process testing between 3DP and CT/MRI presented a considerable degree of similarity in vascular calibers (0.22 ± 1.8 mm), and distances between the tumour and vessel (0.31 ± 0.24 mm). The Dice Similarity Coefficient was 0.92, with a variation of 2%. Bland-Altman plots also demonstrated an agreement between 3DP and the surgical specimen with the distance of the resection margin (1.15 ± 1.52 mm). Professionals considered 3DP at a positive rate of 0.89 (95%CI; 0.73-0.95). According to student's distribution a higher success rate was reached with 3DP (median:0.9, IQR: 0.8-1) compared with CT/MRI or 3D digital imaging (P = 0.01).

CONCLUSION

3DP hepatic models present a good correlation compared with CT/MRI and surgical pathology and they are useful for education, understanding, and surgical planning, but does not necessarily affect the surgical outcome.

Using virtual 3D-models in surgical planning: workflow of an immersive virtual reality application in liver surgery

Purpose

Three-dimensional (3D) surgical planning is widely accepted in liver surgery. Currently, the 3D reconstructions are usually presented as 3D PDF data on regular monitors. 3D-printed liver models are sometimes used for education and planning.

Methods

We developed an immersive virtual reality (VR) application that enables the presentation of preoperative 3D models. The 3D reconstructions are exported as STL files and easily imported into the application, which creates the virtual model automatically. The presentation is possible in “OpenVR”-ready VR headsets. To interact with the 3D liver model, VR controllers are used. Scaling is possible, as well as changing the opacity from invisible over transparent to fully opaque. In addition, the surgeon can draw potential resection lines on the surface of the liver. All these functions can be used in a single or multi-user mode.

Results

Five highly experienced HPB surgeons of our department evaluated the VR application after using it for the very first time and considered it helpful according to the “System Usability Scale” (SUS) with a score of 76.6%. Especially with the subitem “necessary learning effort,” it was shown that the application is easy to use.

Conclusion

We introduce an immersive, interactive presentation of medical volume data for preoperative 3D liver surgery planning. The application is easy to use and may have advantages over 3D PDF and 3D print in preoperative liver surgery planning. Prospective trials are needed to evaluate the optimal presentation mode of 3D liver models.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00423-021-02127-7.

Perceptions of porta-celiac vascular models for hepatic surgery and their use in residency training

BACKGROUND

Primary aspect of hepatic navigation surgery is the identification of source vascular details to preserve healthy liver which has a vascular anatomy quite challenging for the young surgeons. The purpose was to determine whether three-dimensional (3D) vascular pattern models of preoperative computed tomography (CT) images will assist resident-level trainees for hepatic surgery.

METHODS

This study was based on the perception of residents who were presented with 5 different hepatic source vascular patterns and required to compare their perception level of CT, and 1:1 models in terms of importance of variability, differential of patterns and preoperative planning.

RESULTS

All residents agree that models provided better understanding of vascular source and improved preplanning. Five stations provided qualitative assessment with results showing the usefulness of porta-celiac models when used as anatomical tools in preplanning (p = 0.04), simulation of interventional procedures (p = 0.02), surgical education (p = 0.01). None of the cases had scored less than 8.5. Responses related to understanding variations were significantly higher in the perception of the 3D model in all cases, furthermore 3D models were more useful for seniors in more complex cases 3 and 5. Some open-ended answers: "The 3D model can completely change the operation plan" One of the major factors for anatomical resection of liver transplantation is the positional relationship between the hepatic arteries and the portal veins.

CONCLUSION

The plastic-like material presenting the hepatic vascularity enables the visualization of the origin, pattern, shape, and angle of the branches with appropriate spatial perception thus making it well-structured.

Patient-centered oncosurgical planning with cancer models in subspecialty education

BACKGROUND

A fundamental aspect of oncosurgical planning in organ resections is the identification of feeder vessel details to preserve healthy organ tissue while fully resecting the tumors. The purpose of this study was to determine whether three-dimensional (3D) cancer case models of computed tomography (CT) images will assist resident-level trainees in making appropriate operative plans for organ resection surgery.

METHODS

This study was based on the perception of surgery residents who were presented with 5 different oncosurgical scenarios. A five-station carousel including cases of liver mass, stomach mass, annular pancreas, pelvic mass and mediastinal mass was formed for the study. The residents were required to compare their perception level of the cases with their CT images, and 3D models in terms of identifying the invasion of the mass, making differential diagnosis and preoperative planning stage.

RESULTS

All residents have given higher scores for models. 3D models provided better understanding of oncopathological anatomy and improved surgical planning. In all scenarios, 70-80% of the residents preferred the model for preoperative planning. For surgical choice, compared to the CT, the model provided a statistically significant difference in terms of visual assessment, such as tumor location, distal or proximal organotomy (p:0.009). In the evaluation of presacral mass, the perception of model was significantly better than the CT in terms of bone-foramen relationship of chondrosarcoma, its origin, geometric shape, localization, invasion, and surgical preference (p:0.004). The model statistically significantly provided help to evaluate and prepare the case together with the colleagues performing surgery (p:0.007). Commenting on the open-ended question, they stated that the tumor-vessel relationship was clearly demonstrated in the 3D model, which has been very useful.

CONCLUSIONS

With the help of 3D printing technology in this study, it is possible to implement and evaluate a well-structured real patient scenario setup in cancer surgery training. It can be used to improve the understanding of pathoanatomical changes of multidisciplinary oncologic cases. Namely, it is used in guiding the surgical strategy and determining whether patient-specific 3D models change pre-operative planning decisions made by surgeons in complex cancer mass surgical procedures.

Clinical Applications of Patient-Specific 3D Printed Models in Cardiovascular Disease: Current Status and Future Directions

Three-dimensional (3D) printing has been increasingly used in medicine with applications in many different fields ranging from orthopaedics and tumours to cardiovascular disease. Realistic 3D models can be printed with different materials to replicate anatomical structures and pathologies with high accuracy. 3D printed models generated from medical imaging data acquired with computed tomography, magnetic resonance imaging or ultrasound augment the understanding of complex anatomy and pathology, assist preoperative planning and simulate surgical or interventional procedures to achieve precision medicine for improvement of treatment outcomes, train young or junior doctors to gain their confidence in patient management and provide medical education to medical students or healthcare professionals as an effective training tool. This article provides an overview of patient-specific 3D printed models with a focus on the applications in cardiovascular disease including: 3D printed models in congenital heart disease, coronary artery disease, pulmonary embolism, aortic aneurysm and aortic dissection, and aortic valvular disease. Clinical value of the patient-specific 3D printed models in these areas is presented based on the current literature, while limitations and future research in 3D printing including bioprinting of cardiovascular disease are highlighted.

Advanced hepatic vasculobiliary imaging segmentation and 3D reconstruction as an aid in the surgical management of high biliary stenosis

BACKGROUND

Three-dimensional (3D) models are increasingly used to help surgeons, guiding them through the complex hepatic vasculobiliary anatomy. The biliary tract is a relatively untapped territory with only a few case reports described in medical literature. Our aim is to present an innovative 3D reconstruction methodology for biliary imaging and surgical planning, applied to a case of iatrogenic biliary stricture, with fusion of segmented CT and MRI images.

CASE PRESENTATION

A selected case of Bismuth type III iatrogenic biliary stenosis for 3D planning. CT and MR studies were acquired with dedicated protocols for segmentation. Two radiologists performed segmentation and 3D model post-processing, fusing both imaging techniques to faithfully render the anatomical structures. Measurements of anatomical landmarks were taken in both the CT/MRI and the 3D model to assure its accuracy and differences in measurement were calculated. The 3D model replicates anatomical structures and pathology with high accuracy, with only 2.2% variation between STL, CT and MRI measurements. The model was discussed with the surgical team and used in the surgical planning, improving confidence in this delicate procedure, due to the detailed prior knowledge of the patient's anatomy.

CONCLUSION

Three-dimensional reconstructions are a rapidly growing area of research with a significant impact in the personalized and precision medicine. The construction of 3D models that combine vascular and biliary anatomy, using different imaging techniques, respectively CT and MRI, will predictably contribute to a more rigorous planning of complex liver surgeries.

Producing three-dimensional printed models of the hepatobiliary system from computed tomography imaging data

INTRODUCTION

Macroscopic anatomy has traditionally been taught using cadaveric material, lectures and a variety of additional resources including online modules and anatomical models. Traditional plastic models are effective educational tools yet they have significant drawbacks such as a lack of anatomical detail, a lack of texturisation and cost. Three-dimensional printed models stand to solve these problems and widen access to high-quality anatomical teaching. This paper outlines the use of three-dimensional multiplanar imaging (computed tomography) in the development of an accurate model of the hepatobiliary system.

MATERIALS AND METHODS

Computed tomography scans were used to construct a virtual three-dimensional model of the hepatobiliary system. This was printed locally as a full-size colour model. We give a complete account of the process and software used.

DISCUSSION

This study is among the first of a series in which we will document the newly formed Oxford Library of Anatomy. This series will provide the methodology for the production of three-dimensional models from computed tomography and magnetic resonance imaging scans, and the library will provide a complete collection of the most complex anatomical areas. We hope that these models will form an important adjunct in teaching anatomy to medical students and surgical trainees.

Three-Dimensional Augmented Reality Visualization Informs Locoregional Therapy in a Translational Model of Hepatocellular Carcinoma

PURPOSE

To evaluate the utility of visualizing preprocedural MR images in 3-dimensional (3D) space using augmented reality (AR) before transarterial embolization of hepatocellular carcinoma (HCC) in a preclinical model.

MATERIALS AND METHODS

A total of 28 rats with diethylnitrosamine-induced HCCs > 5 mm treated with embolization were included in a prospective study. In 12 rats, 3D AR visualization of preprocedural MR images was performed before embolization. Procedural metrics including catheterization time and radiation exposure were compared vs a prospective cohort of 16 rats in which embolization was performed without AR. An additional cohort of 15 retrospective cases was identified and combined with the prospective control cohort (n = 31) to improve statistical power.

RESULTS

A 37% reduction in fluoroscopy time, from 11.7 min to 7.4 minutes, was observed with AR when compared prospectively, which did not reach statistical significance (P = .12); however, when compared with combined prospective and retrospective controls, the reduction in fluoroscopy time from 14.1 min to 7.4 minutes (48%) was significant (P = .01). A 27% reduction in total catheterization time, from 42.7 minutes to 31.0 minutes, was also observed with AR when compared prospectively, which did not reach statistical significance (P = .11). No significant differences were seen in dose-area product or air kerma prospectively.

CONCLUSIONS

Three-dimensional AR visualization of preprocedural imaging may aid in the reduction of procedural metrics in a preclinical model of transarterial embolization. These data support the need for further studies to evaluate the potential of AR in endovascular oncologic interventions.

There Is a Great Future in Plastics: Personalized Approach to the Management of Hilar Cholangiocarcinoma Using a 3-D-Printed Liver Model

In recent years, three-dimensional (3-D) printing technology has become a standard tool that is used in several medical applications such as education, surgical training simulation and planning, and doctor-patient communication. Although liver surgery is ideally complemented by the use of preoperative 3-D-printed models, only a few publications have addressed this topic. We report the case of a 29-year-old Caucasian woman admitted for a Klatskin tumor infiltrating the right portal vein requiring surgery that required complex vascular reconstruction. A life-sized liver model with colorful plastic vessels and realistic looking tumor was created with the aim of planning an optimal surgical approach. According to the 3-D model, we performed a right hepatic trisectionectomy, also removing enbloc the tract of portal vein encased by the tumor and the neoplastic thrombus, followed by a complex vascular reconstruction between the main portal vein and the left portal branch. After 22 months of follow-up, the patient was alive and continuing chemotherapy. The use of the 3-D models in liver surgery helps clarify several useful preoperative issues. The accuracy of the model regarding anatomical findings was high. In the case of complex vascular reconstruction strategies, rational use of 3-D printing technology should be implemented.

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.

Surgical planning with patient-specific three-dimensional printed pancreaticobiliary disease models - Cross-sectional study

BACKGROUND

Three-dimensional (3D) printing has been increasingly used in medical applications with the creation of accurate patient-specific 3D printed models in medical imaging data. This study has been planned based on the fact that research on 3D printing in pancreaticobiliary disease is limited due to lack of studies on validation of model accuracy.

METHODS

This is an innovative study where general surgery residents are presented 5 distinct hepatopancreatobiliary disease scenarios to generate a perception and required to compare their perception level of these cases with magnetic resonance cholangiopancreatography (MRCP), 3D images and 1:1 solid models that the pathology, diverse diagnosis and presurgery diagnosis stages can be observed. This study is single-centered.

RESULTS

The dilated pancreaticobiliary intervention based on scenarios for general surgery residency was more original since there was no prior study that includes both model building and the evaluation of the perception created by the model. Five scenarios provided qualitative assessment with results showing the usefulness of 3D models when used as clinical tools in preoperative planning, simulation of interventional procedures, surgical education, and training. The perception level in the 3D model, MRCP (Z: 3.854, p: 0.000) and the 3D image (Z: 2.865, p: 0.004) was higher; likewise, the 3D-STL image was higher compared to the MRCP image (Z: 3.779, p: 0.000). All subspecialists agree that 3D models provided better understanding of dilated pancreaticobiliary pathoanatomy and improved surgical planning.

CONCLUSIONS

A thoroughly outlined genuine patient situation layout aimed for general surgery training can be installed and monitored with the support of 3D printing technology of this study. This can be utilized to develop the comprehension of pathoanatomical variations of complex pancreaticobiliary illness and to adopt a surgical approach.

Development of patient-specific 3D-printed breast phantom using silicone and peanut oils for magnetic resonance imaging

Background

Despite increasing reports of 3D printing in medical applications, the use of 3D printing in breast imaging is limited, thus, personalized 3D-printed breast model could be a novel approach to overcome current limitations in utilizing breast magnetic resonance imaging (MRI) for quantitative assessment of breast density. The aim of this study is to develop a patient-specific 3D-printed breast phantom and to identify the most appropriate materials for simulating the MR imaging characteristics of fibroglandular and adipose tissues.

Methods

A patient-specific 3D-printed breast model was generated using 3D-printing techniques for the construction of the hollow skin and fibroglandular region shells. Then, the T1 relaxation times of the five selected materials (agarose gel, silicone rubber with/without fish oil, silicone oil, and peanut oil) were measured on a 3T MRI system to determine the appropriate ones to represent the MR imaging characteristics of fibroglandular and adipose tissues. Results were then compared to the reference values of T1 relaxation times of the corresponding tissues: 1,324.42±167.63 and 449.27±26.09 ms, respectively. Finally, the materials that matched the T1 relaxation times of the respective tissues were used to fill the 3D-printed hollow breast shells.

Results

The silicone and peanut oils were found to closely resemble the T1 relaxation times and imaging characteristics of these two tissues, which are 1,515.8±105.5 and 405.4±15.1 ms, respectively. The agarose gel with different concentrations, ranging from 0.5 to 2.5 wt%, was found to have the longest T1 relaxation times.

Conclusions

A patient-specific 3D-printed breast phantom was successfully designed and constructed using silicone and peanut oils to simulate the MR imaging characteristics of fibroglandular and adipose tissues. The phantom can be used to investigate different MR breast imaging protocols for the quantitative assessment of breast density.

Use of Three-dimensional Printing in the Development of Optimal Cardiac CT Scanning Protocols

Three-dimensional (3D) printing is increasingly used in medical applications with most of the studies focusing on its applications in medical education and training, pre-surgical planning and simulation, and doctor-patient communication. An emerging area of utilising 3D printed models lies in the development of cardiac computed tomography (CT) protocols for visualisation and detection of cardiovascular disease. Specifically, 3D printed heart and cardiovascular models have shown potential value in the evaluation of coronary plaques and coronary stents, aortic diseases and detection of pulmonary embolism. This review article provides an overview of the clinical value of 3D printed models in these areas with regard to the development of optimal CT scanning protocols for both diagnostic evaluation of cardiovascular disease and reduction of radiation dose. The expected outcomes are to encourage further research towards this direction.

Decision-making based on 3D printed models in laparoscopic liver resections with intraoperative ultrasound: a prospective observational study

OBJECTIVES

The aim of this study was to evaluate impact of 3D printed models on decision-making in context of laparoscopic liver resections (LLR) performed with intraoperative ultrasound (IOUS) guidance.

METHODS

Nineteen patients with liver malignances (74% were colorectal cancer metastases) were prospectively qualified for LLR or radiofrequency ablation in a single center from April 2017 to December 2018. Models were 3DP in all cases based on CT and facilitated optical visualization of tumors' relationships with portal and hepatic veins. Planned surgical extent and its changes were tracked after CT analysis and 3D model inspection, as well as intraoperatively using IOUS.

RESULTS

Nineteen patients were included in the analysis. Information from either 3DP or IOUS led to changes in the planned surgical approach in 13/19 (68%) patients. In 5/19 (26%) patients, the 3DP model altered the plan of the surgery preoperatively. In 4/19 (21%) patients, 3DP independently changed the approach. In one patient, IOUS modified the plan post-3DP. In 8/19 (42%) patients, 3DP model did not change the approach, whereas IOUS did. In total, IOUS altered surgical plans in 9 (47%) cases. Most of those changes (6/9; 67%) were caused by detection of additional lesions not visible on CT and 3DP.

CONCLUSIONS

3DP can be helpful in planning complex and major LLRs and led to changes in surgical approach in 26.3% (5/19 patients) in our series. 3DP may serve as a useful adjunct to IOUS.

KEY POINTS

• 3D printing can help in decision-making before major and complex resections in patients with liver cancer. • In 5/19 patients, 3D printed model altered surgical plan preoperatively. • Most surgical plan changes based on intraoperative ultrasonography were caused by detection of additional lesions not visible on CT and 3D model.

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.

Personalized Three-Dimensional Printed Models in Congenital Heart Disease

Patient-specific three-dimensional (3D) printed models have been increasingly used in cardiology and cardiac surgery, in particular, showing great value in the domain of congenital heart disease (CHD). CHD is characterized by complex cardiac anomalies with disease variations between individuals; thus, it is difficult to obtain comprehensive spatial conceptualization of the cardiac structures based on the current imaging visualizations. 3D printed models derived from patient's cardiac imaging data overcome this limitation by creating personalized 3D heart models, which not only improve spatial visualization, but also assist preoperative planning and simulation of cardiac procedures, serve as a useful tool in medical education and training, and improve doctor-patient communication. This review article provides an overall view of the clinical applications and usefulness of 3D printed models in CHD. Current limitations and future research directions of 3D printed heart models are highlighted.

Investigating accuracy of 3D printed liver models with computed tomography

Background

The aim of this study was to evaluate the accuracy of three-dimensional (3D) printed liver models developed by a cost-effective approach for establishing validity of using these models in a clinical setting.

Methods

Fifteen patients undergoing laparoscopic liver resection in a single surgical department were included. Patient-specific, 1-1 scale 3D printed liver models including the liver, tumor, and vasculature were created from contrast-enhanced computed tomography (CT) images using a cost-effective approach. The 3D models were subsequently CT scanned, 3D image post-processing was performed, and these 3D computer models (MCT) were compared to the original 3D models created from the original patient images (PCT). 3D computer models of each type were co-registered using a point set registration method. 3D volume measurements of the liver and lesions were calculated and compared for each set. In addition, Hausdorff distances were calculated and surface quality was compared by generated heatmaps.

Results

The median liver volume in MCT was 1,281.84 [interquartile range (IQR) =296.86] cm³, and 1,448.03 (IQR =413.23) cm³ in PCT. Analysis of differences between surfaces showed that the median value of mean Hausdorff distances for liver parenchyma was 1.92 mm. Bland-Altman plots revealed no significant bias in liver volume and diameters of hepatic veins and tumor location. Median errors of all measured vessel diameters were smaller than CT slice height. There was a slight trend towards undersizing anatomical structures, although those errors are most likely due to source imaging.

Conclusions

We have confirmed the accuracy of 3D printed liver models created by using the low-cost method. 3D models are useful tools for pre-operative planning and intra-operative guidance. Future research in this field should continue to move towards clinical trials for assessment of the impact of these models on pre-surgical planning decisions and perioperative outcomes.

Patient-specific 3D printed model of biliary ducts with congenital cyst

BACKGROUND

3D printing has shown great promise in medical applications, with increasing reports in liver diseases. However, research on 3D printing in biliary disease is limited with lack of studies on validation of model accuracy. In this study, we presented our experience of creating a realistic 3D printed model of biliary ducts with congenital cyst. Measurements of anatomical landmarks were compared at different stages of model generation to determine dimensional accuracy.

METHODS

Contrast-enhanced computed tomography (CT) images of a patient diagnosed with congenital cyst in the common bile duct with dilated hepatic ducts were used to create the 3D printed model. The 3D printed model was scanned on a 64-slice CT scanner using the similar abdominal CT protocol. Measurements of anatomical structures including common hepatic duct (CHD), right hepatic duct (RHD), left hepatic duct (LHD) and the cyst at left to right and anterior to posterior dimensions were performed and compared between original CT images, the standard tessellation language (STL) image and CT images of the 3D model.

RESULTS

The 3D printing model was successfully generated with replication of biliary ducts and cyst. Significant differences in measurements of these landmarks were found between the STL and the original CT images, and the CT images of the 3D printed model and the original CT images (P<0.05). Measurements of the RHD and LHD diameters from the original CT images were significantly larger than those from the CT images of 3D model or STL file (P<0.05), while measurements of the CHD diameters were significantly smaller than those of the other two datasets (P<0.05). No significant differences were reached in measurements of the CHD, RHD, LHD and the biliary cyst between CT images of the 3D printed model and STL file (P=0.08-0.98).

CONCLUSIONS

This study shows our experience in producing a realistic 3D printed model of biliary ducts and biliary cyst. The model was found to replicate anatomical structures and cyst with high accuracy between the STL file and the CT images of the 3D model. Large discrepancy in dimensional measurements was noted between the original CT and STL file images, and the original CT and CT images of the 3D model, highlighting the necessity of further research with inclusion of more cases of biliary disease to validate accuracy of 3D printed biliary models.

Impact of 3D printing technology on the comprehension of surgical liver anatomy

BACKGROUND AND AIMS

Surgical planning in liver resection depends on the precise understanding of the three-dimensional (3D) relation of tumors to the intrahepatic vascular trees. This study aimed to investigate the impact of 3D printing (3DP) technology on the understanding of surgical liver anatomy.

METHODS

We selected four hepatic tumors that were previously resected. For each tumor, a virtual 3D reconstruction (VIR) model was created from multi-detector computed tomography (MDCT) and was prototyped using a 3D printer. Forty-five surgical residents were evenly assigned to each group (3DP, VIR, and MDCT groups). After evaluation of the MDCT scans, VIR model, or 3DP model of each tumor, surgical residents were asked to assign hepatic tumor locations and state surgical resection proposals. The time used to specify the tumor location was recorded. The correct responses and time spent were compared between the three groups.

RESULTS

The assignment of tumor location improved steadily from MDCT, to VIR, and to 3DP, with a mean score of 34.50, 55.25, and 80.92, respectively. These scores were out of 100 points. The 3DP group had significantly higher scores compared with other groups (p < 0.001). Furthermore, 3DP significantly improved the accuracy of surgical resection proposal (p < 0.001). The mean accuracy of the surgical resection proposal for 3DP, VIR, and MDCT was 57, 25, and 25%, respectively. The 3DP group took significantly less time, compared with other groups (p < 0.005). The mean time spent on assessing the tumor location for 3DP, VIR, and MDCT groups was 93, 223, and 286 s, respectively.

CONCLUSIONS

3D printing improves the understanding of surgical liver anatomy for surgical residents. The improved comprehension of liver anatomy may facilitate laparoscopy or open liver resection.