Three-dimensional printing: review of application in medicine and hepatic surgery

Research advances and trends in anatomy from 2013 to 2023: A visual analysis based on CiteSpace and VOSviewer

As the cornerstone of medicine, the development of anatomy is related to many disciplines and fields and has received extensive attention from researchers. How to integrate and grasp the cutting-edge information in this field quickly is a challenge for researchers, so the aim of this study is to analyze research in anatomy using CiteSpace and VOSviewer in order to identify research hotspots and future directions. To offer a fresh viewpoint for assessing the academic influences of researchers, nations, or institutions on anatomy, and to examine the development of hotspots in anatomical study and to forecast future trends. A total of 4637 anatomy-related publications from 2013 to 2023 were collected from Web of Science Core Collection databases. Their temporal distribution, spatial distribution, cited authors, co-cited journals, keywords, and disciplinary connections in the literature were analyzed using CiteSpace and VOSviewer, and a knowledge graph was constructed. The temporal distribution shows a general fluctuation in the amount of literature published from 2013 to 2023. In spatial distribution, the total number of published articles was highest in the United States, the United Kingdom, and China, the United States leading. Tubbs, Rhoton, Iwanaga, and LaPrade are important authors in anatomy. Clinical Anatomy, Surgical and Radiologic Anatomy, and Journal of Anatomy were the most highly cited journals. Analysis of keywords and citation emergence showed that the research hotspots and trends in anatomy focused mainly on anatomy education, digital technology, and surgical management. At the same time, anatomy showed a trend toward multidisciplinary crossover, developing closer relationships with molecular biology, immunology, and clinical medicine. Current research in anatomy focuses on innovative reform of the educational model and the application and promotion of digital technology. Also, multidisciplinary cross-fertilization is an inevitable trend for the future development of anatomy.

Application of 3-dimensional visualization and image fusion technology in liver cancer with portal vein tumor thrombus surgery

Liver cancer with portal vein tumor thrombus (PVTT) is a frequent finding and is related to poor prognosis. Surgical resection provides a more promising prognosis in selected patients. The purpose of this study was to explore the application of 3D (3-dimensional) visualization and image fusion technology in liver cancer with PVTT surgery. 12 patients were treated with surgery between March 2019 and August 2022. The preoperative standard liver volume (SLV), estimated future liver remnant (FLR), FLR/SLV, 3D visualization models, PVTT classification, operation programs, surgical results, and prognosis were collected and analyzed. Twelve patients who had complete data of 3D visualization and underwent hemihepatectomy combined with portal vein tumor thrombectomy. The operation plan was formulated by 3D visualization and was highly consistent with the actual surgery. The SLV was 1208.33 ± 63.22 mL, FLR was 734.00 mL and FLR/SLV was 61.62 ± 19.38%. The accuracy of classification of PVTT by 3D visualization was 100%, Cheng type Ⅱa (4 cases), Ⅱb (2 cases), Ⅲa (4 cases), and Ⅲb (2 cases). The 3D visualization model was a perfect fusion with the intraoperative live scene and precise guidance for hepatectomy. No patient was suffering from postoperative liver failure and without procedure‑associated death. 6 patients died of tumor recurrence, and 2 patients died of other reasons. The 12-month cumulative survival rate was 25.9%. 3D visualization and image fusion technology could be used for precise assessment of FLR, classification of PVTT, surgery navigation, and which was helpful in improving the safety of hepatectomy.

Three-dimensional Liver Model Application for Liver Transplantation

BACKGROUND

Children are removed from the liver transplant waitlist because of death or progressive illness. Size mismatch accounts for 30% of organ refusal. This study aimed to demonstrate that 3-dimensional (3D) technology is a feasible and accurate adjunct to organ allocation and living donor selection process.

METHODS

This prospective multicenter study included pediatric liver transplant candidates and living donors from January 2020 to February 2023. Patient-specific, 3D-printed liver models were used for anatomic planning, real-time evaluation during organ procurement, and surgical navigation. The primary outcome was to determine model accuracy. The secondary outcome was to determine the impact of outcomes in living donor hepatectomy. Study groups were analyzed using propensity score matching with a retrospective cohort.

RESULTS

Twenty-eight recipients were included. The median percentage error was -0.6% for 3D models and had the highest correlation to the actual liver explant (Pearson's R = 0.96, P < 0.001) compared with other volume calculation methods. Patient and graft survival were comparable. From 41 living donors, the median percentage error of the allograft was 12.4%. The donor-matched study group had lower central line utilization (21.4% versus 75%, P = 0.045), shorter length of stay (4 versus 7 d, P = 0.003), and lower mean comprehensive complication index (3 versus 21, P = 0.014).

CONCLUSIONS

Three-dimensional volume is highly correlated with actual liver explant volume and may vary across different allografts for living donation. The addition of 3D-printed liver models during the transplant evaluation and organ procurement process is a feasible and safe adjunct to the perioperative decision-making process.

Three-Dimensional Printing as a Progressive Innovative Tool for Customized and Precise Drug Delivery

While using three-dimensional printing, materials are deposited layer by layer in accordance with the digital model created by computer-aided design software. Numerous research teams have shown interest in this technology throughout the last few decades to produce various dosage forms in the pharmaceutical industry. The number of publications has increased since the first printed medicine was approved in 2015 by Food and Drug Administration. Considering this, the idea of creating complex, custom-made structures that are loaded with pharmaceuticals for tissue engineering and dose optimization is particularly intriguing. New approaches and techniques for creating unique medication delivery systems are made possible by the development of additive manufacturing keeping in mind the comparative advantages it has over conventional methods of manufacturing medicaments. This review focuses on three-dimensional printed formulations grouped in orally disintegrated tablets, buccal films, implants, suppositories, and microneedles. The various types of techniques that are involved in it are summarized. Additionally, challenges and applications related to three-dimensional printing of pharmaceuticals are also being discussed.

Three-Dimensional Printing and Bioprinting in Renal Transplantation and Regenerative Medicine: Current Perspectives

For patients with end-stage kidney disease (ESKD), renal transplantation is the treatment of choice, constituting the most common solid organ transplantation. This study aims to provide a comprehensive review regarding the application of three-dimensional (3D) printing and bioprinting in renal transplantation and regenerative medicine. Specifically, we present studies where 3D-printed models were used in the training of surgeons through renal transplantation simulations, in patient education where patients acquire a higher understanding of their disease and the proposed operation, in the preoperative planning to facilitate decision-making, and in fabricating customized, tools and devices. Three-dimensional-printed models could transform how surgeons train by providing surgical rehearsal platforms across all surgical specialties, enabling training with tissue realism and anatomic precision. The use of 3D-printed models in renal transplantations has shown a positive impact on surgical outcomes, including the duration of the operation and the intraoperative blood loss. Regarding 3D bioprinting, the technique has shown promising results, especially in the field of microfluidic devices, with the development of tissue demonstrating proximal tubules, glomerulus, and tubuloinerstitium function, and in renal organoid development. Such models can be applied for renal disease modeling, drug development, and renal regenerative medicine.

3D printing of pharmaceuticals: approach from bench scale to commercial development

Background

The three-dimensional (3D) printing is paradigm shift in the healthcare sector. 3D printing is platform technologies in which complex products are developed with less number of additives. The easy development process gives edge over the conventional methods. Every individual needs specific dose treatment. 'One size fits all' is the current traditional approach that can shift to more individual specific in 3D printing. The present review aims to cover different perspectives regarding selection of drug, polymer and technological aspects for 3D printing. With respect to clinical practice, regulatory issue and industrial potential are also discussed in this paper.

Main body

The individualization of medicines with patient centric dosage form will become reality in upcoming future. It provides individual's need of dose by considering genetic profile, physiology and diseased condition. The tailormade dosages with unique drug loading and release profile of different geometrical shapes and sizes can easily deliver therapeutic dose. The technology can fulfill growing demand of efficiency in the dose accuracy for the patient oriented sectors like pediatric, geriatric and also easy to comply with cGMP requirements of regulated market. The clinical practice can focus on prescribing each individual's necessity of dose.

Conclusion

In the year 2015, FDA approved first 3D printed drug product, which is initiator in the new phase of manufacturing of pharmaceuticals. The tailormade formulations can be made in future for personalized medications. Regulatory approval from agencies can bring the 3DP product into the market. In the future, formulators can bring different sector-specific products for personalized need through 3DP pharmaceutical product.

Graphical Abstract

Role of three-dimensional printing and artificial intelligence in the management of hepatocellular carcinoma: Challenges and opportunities

Hepatocellular carcinoma (HCC) constitutes the fifth most frequent malignancy worldwide and the third most frequent cause of cancer-related deaths. Currently, treatment selection is based on the stage of the disease. Emerging fields such as three-dimensional (3D) printing, 3D bioprinting, artificial intelligence (AI), and machine learning (ML) could lead to evidence-based, individualized management of HCC. In this review, we comprehensively report the current applications of 3D printing, 3D bioprinting, and AI/ML-based models in HCC management; we outline the significant challenges to the broad use of these novel technologies in the clinical setting with the goal of identifying means to overcome them, and finally, we discuss the opportunities that arise from these applications. Notably, regarding 3D printing and bioprinting-related challenges, we elaborate on cost and cost-effectiveness, cell sourcing, cell viability, safety, accessibility, regulation, and legal and ethical concerns. Similarly, regarding AI/ML-related challenges, we elaborate on intellectual property, liability, intrinsic biases, data protection, cybersecurity, ethical challenges, and transparency. Our findings show that AI and 3D printing applications in HCC management and healthcare, in general, are steadily expanding; thus, these technologies will be integrated into the clinical setting sooner or later. Therefore, we believe that physicians need to become familiar with these technologies and prepare to engage with them constructively.

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.

3D bioprinting of dual-crosslinked nanocellulose hydrogels for tissue engineering applications

Hydrogels based on cellulose nanofibrils (CNFs) have been widely used as scaffolds for biomedical applications, however, the poor mechanical properties of CNF hydrogels limit their use as ink for 3D bioprinting in order to generate scaffolds for tissue engineering applications. In this study, a dual crosslinkable hydrogel ink composed of a poly(ethylene glycol) (PEG) star polymer and 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO)-oxidized nanocellulose fibers (CNFs) is presented. As the resulting hydrogel had low structural integrity, at first crosslinking of CNFs was introduced by Ca²⁺. Strong physical interactions between CNFs and Ca²⁺ cations allowed easy regulation of the viscosity of the inks for extrusion printing raising the solution viscosity by more than 1.5 times depending on the amount of Ca²⁺ added. The resulting hydrogel had high structural integrity and was further stabilized in a second step by photo crosslinking of PEG under visible light. In only a few seconds, hydrogels with Young's modulus between ∼10 and 30 kPa were obtained just by altering the CNF and Ca²⁺ content. 3D printed hydrogels supported fibroblasts with excellent cell viability and proliferation. The dual crosslinkable hydrogel ink herein developed is versatile, easy to prepare, and suitable for 3D printing of bioscaffolds with highly tailored viscoelastic and mechanical properties applicable in a wide range of regenerative medicines.

Endoscopic Endonasal Approach for Clipping Anterior Communicating Artery Aneurysms From Cadaver Studies and Three-Dimensional Printed Models to a Clinical Case

OBJECTIVES

Anterior communicating artery (ACoA) aneurysm is one of the most common intracranial aneurysms, and it is also the aneurysm with the highest rupture rate. With the improvement of endoscopic techniques, it is possible to use an endoscopic endonasal approach (EEA) to clip ACoA aneurysms. For further analysis of the EEA for clipping ACoA aneurysms, we used cadaver heads and three-dimensional (3D)-printed models to finish the anatomical study, and we finally selected 1 clinical case to complete the clipping through the EEA.

MATERIALS AND METHODS

We first collected 3 cadaver heads to simulate the EEA. Then, the imaging data of 29 real cases of ACoA aneurysm were collected, and the model of an aneurysm was prepared by 3D printing technology; then, the EEA was used to simulate the clipping of the aneurysm model. Finally, a clinical case with 2 ACoA aneurysms was selected to adopt the EEA for clipping.

RESULTS

Both the cadaver head and 3D-printed aneurysm model could simulate aneurysm clipping with the EEA. The clinical case of the selected ACoA aneurysm can successfully complete the clipping through the EEA.

CONCLUSIONS

3D-printed models are a good method to study the anatomical characteristics of a surgical approach. For specially selected ACoA aneurysms, the EEA is relatively simple method that can be used to clip the aneurysm successfully. The EEA for clipping ACoA aneurysms is a useful complement to the current traditional craniotomy approaches and endovascular embolization.

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.

Hot melt extrusion: An emerging manufacturing method for slow and sustained protein delivery

With the rapid development of the biopharmaceutical industry, an increasing number of new therapeutic protein products (TPPs) have been approved by the FDA and many others are under pre-clinical and clinical evaluation. A major limitation of biopharmaceuticals is their limited half-life when administered systemically. A one-time, implantable, sustained protein delivery device would be advantageous in order to improve the quality of life of patients. Hot melt extrusion (HME) is a mature technology that has been extensively used for a broad spectrum of applications in the polymer and pharmaceutical industry and has achieved success as evidenced by a variety of FDA-approved commercial products. These commercial products are mostly for sustained delivery of small molecule therapeutics, leaving a significant gap for HME formulation of therapeutic proteins. With the increasing need of sustained TPP delivery, HME shows promise as a downstream processing method due to its high efficiency and economic value. Several challenges remain for the application of HME in protein delivery. Progress of HME for protein delivery, challenges encountered, and potential solutions will be detailed in this review article. This article is categorized under: Implantable Materials and Surgical Technologies > Nanomaterials and Implants Biology-Inspired Nanomaterials > Protein and Virus-Based Structures.

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.

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

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

Three-dimensional printing in medicine: a systematic review of pediatric applications

BACKGROUND

Three-dimensional printing (3DP) addresses distinct clinical challenges in pediatric care including: congenital variants, compact anatomy, high procedural risk, and growth over time. We hypothesized that patient-specific applications of 3DP in pediatrics could be categorized into concise, discrete categories of use.

METHODS

Terms related to "three-dimensional printing" and "pediatrics" were searched on PubMed, Scopus, Ovid MEDLINE, Cochrane CENTRAL, and Web of Science. Initial search yielded 2122 unique articles; 139 articles characterizing 508 patients met full inclusion criteria.

RESULTS

Four categories of patient-specific 3DP applications were identified: Teaching of families and medical staff (9.3%); Developing intervention strategies (33.9%); Procedural applications, including subtypes: contour models, guides, splints, and implants (43.0%); and Material manufacturing of shaping devices or prosthetics (14.0%). Procedural comparative studies found 3DP devices to be equivalent or better than conventional methods, with less operating time and fewer complications.

CONCLUSION

Patient-specific applications of Three-Dimensional Printing in Medicine can be elegantly classified into four major categories: Teaching, Developing, Procedures, and Materials, sharing the same TDPM acronym. Understanding this schema is important because it promotes further innovation and increased implementation of these devices to improve pediatric care.

IMPACT

This article classifies the pediatric applications of patient-specific three-dimensional printing. This is a first comprehensive review of patient-specific three-dimensional printing in both pediatric medical and surgical disciplines, incorporating previously described classification schema to create one unifying paradigm. Understanding these applications is important since three-dimensional printing addresses challenges that are uniquely pediatric including compact anatomy, unique congenital variants, greater procedural risk, and growth over time. We identified four classifications of patient-specific use: teaching, developing, procedural, and material uses. By classifying these applications, this review promotes understanding and incorporation of this expanding technology to improve the pediatric care.

Surgical training 2.0: A systematic approach reviewing the literature focusing on oral maxillofacial surgery - Part I

PURPOSE

Many technologies are emerging in the medical field. Having an overview of the technological arsenal available to train new surgeons seems very interesting to guide subsequent surgical training protocols.

METHODS

This article is a systematic approach reviewing new technologies in surgical training, in particular in oral and maxillofacial surgery. This review explores what new technologies can do compared to traditional methods in the field of surgical education. A structured literature search of PubMed was performed in adherence to PRISMA guidelines. The articles were selected when they fell within predefined inclusion criteria while respecting the key objectives of this systematic review. We looked at medical students and more specifically in surgery and analysed whether exposure to new technologies improved their surgical skills compared to traditional methods. Each technology is reviewed by highlighting its advantages and disadvantages and studying the feasibility of integration into current practice.

RESULTS

The results are encouraging. Indeed, all of these technologies make it possible to reduce the learning time, the operating times, the operating complications and increase the enthusiasm of the students compared to more conventional methods. The start-up cost, the complexity to develop new models, and the openness of mind necessary for the integration of these technologies are all obstacles to immediate development. The main limitations of this review are that many of the studies have been carried out on small numbers, they are not interested in acquiring knowledge or skills over the long term and obviously there is a publication bias.

CONCLUSION

Surgical education methods will probably change in the years to come, integrating these new technologies into the curriculum seems essential so as not to remain on the side. This first part therefore reviews, open field camera, telemedicine and 3D printing. This systematic review is registered on PROSPERO.

3D Printing as a Promising Tool in Personalized Medicine

Personalized medicine has the potential to revolutionize the healthcare sector, its goal being to tailor medication to a particular individual by taking into consideration the physiology, drug response, and genetic profile of that individual. There are many technologies emerging to cause this paradigm shift from the conventional "one size fits all" to personalized medicine, the major one being three-dimensional (3D) printing. 3D printing involves the establishment of a three-dimensional object, in a layer upon layer manner using various computer software. 3D printing can be used to construct a wide variety of pharmaceutical dosage forms varying in shape, release profile, and drug combination. The major technological platforms of 3D printing researched on in the pharmaceutical sector include inkjet printing, binder jetting, fused filament fabrication, selective laser sintering, stereolithography, and pressure-assisted microsyringe. A possible future application of this technology could be in a clinical setting, where prescriptions could be dispensed based on individual needs. This manuscript points out the various 3D printing technologies and their applications in research for fabricating pharmaceutical products, along with their pros and cons. It also presents its potential in personalized medicine by individualizing the dose, release profiles, and incorporating multiple drugs in a polypill. An insight on how it tends to various populations is also provided. An approach of how it can be used in a clinical setting is also highlighted. Also, various challenges faced are pointed out, which must be overcome for the success of this technology in personalized medicine.

Hydrogel-based 3D bioprints repair rat small intestine injuries and integrate into native intestinal tissue

3D Printing has become a mainstay of industry, with several applications in the medical field. One area that could benefit from 3D printing is intestinal failure due to injury or genetic malformations. We bioprinted cylindrical tubes from rat vascular cells that were sized to form biopatches. 2 mm enterotomies were made in the small intestine of male Sprague-Dawley rats, and sealed with biopatches. These intestinal segments were connected to an ex vivo perfusion device that provided independent extraluminal and intraluminal perfusion. The fluorescence signal of fluorescein isothiocyanate (FITC)-inulin in the intraluminal perfusate, a non-absorbable fluorescent marker of intestinal integrity, was measured every 15 min over 90 min, and used to assess the integrity of the segments under both continuous perfusion and alternate-flow perfusion. Enterotomies were made an inch away from the ileocecal junction in male Wistar rats and sealed with biopatches. The animals were monitored daily and euthanized at post-operative days 7, 14, 21, and 30. Blinded histopathological analysis was conducted to compare the patch segments to native intestine. Biopatch-sealed intestinal segments withstood both continuous and pulsatile flow rates without leakage of FITC-inulin above the control baseline. 21 of 26 animals survived with normal activity, weight gain, and stool output. Histopathology of the explanted segments showed progressive villi and crypt formation over the enterotomies, with complete restoration of the epithelium by 30 days. This study presents a novel application of 3D bioprinting to develop a universal repair patch that can seal lesions in vivo, and fully integrate into the native intestine.

3D printed bismuth oxide-polylactic acid composites for radio-mimetic computed tomography spine phantoms

Polylactic acid (PLA) composite filaments with varying concentrations of bismuth oxide microparticle additives were fabricated for use with commercially available fused filament fabrication (FFF) printing systems for the production of spine phantoms that mimic the radiopacity of bone. Thermal analysis showed that the additives had limited impact on the glass transition temperature and melting point of the filaments, allowing for their use in commercial FFF systems with standard printer settings. The ultimate strength of the printed test specimens was found to reduce slightly when bismuth oxide was added in high concentrations, with a moderate reduction of 12% compared to PLA at the highest concentration of 30 wt%. The modulus of the specimens increased by up to 24% with the addition of the additive. The radiopacity of specimens printed with the composite filaments were measured by X-ray microcomputed tomography (micro-CT) and clinical computed tomography (CT). The CT number was found to increase by approximately 196 HU per wt% of bismuth oxide added to the filaments. A phantom model of a cervical spine deformity was successfully printed by FFF with a composite filament which was calibrated to mimic the radiopacity of cervical and cortical bone. The results indicate that the composite filaments have direct applicability for the production of phantoms used for education and preoperative planning.

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.

Identifying a commercially-available 3D printing process that minimizes model distortion after annealing and autoclaving and the effect of steam sterilization on mechanical strength

BACKGROUND

Fused deposition modeling 3D printing is used in medicine for diverse purposes such as creating patient-specific anatomical models and surgical instruments. For use in the sterile surgical field, it is necessary to understand the mechanical behavior of these prints across 3D printing materials and after autoclaving. It has been previously understood that steam sterilization weakens polylactic acid, however, annealing heat treatment of polylactic acid increases its crystallinity and mechanical strength. We aim to identify an optimal and commercially available 3D printing process that minimizes distortion after annealing and autoclaving and to quantify mechanical strength after these interventions.

METHODS

Thirty millimeters cubes with four different infill geometries were 3D printed and subjected to hot water-bath annealing then immediate autoclaving. Seven commercially available 3D printing materials were tested to understand their mechanical behavior after intervention. The dimensions in the X, Y, and Z axes were measured before and after annealing, and again after subsequent autoclaving. Standard and strength-optimized Army-Navy retractor designs were printed using the 3D printing material and infill geometry that deformed the least. These retractors were subjected to annealing and autoclaving interventions and tested for differences in mechanical strength.

RESULTS

For both the annealing and subsequent autoclaving intervention, the material and infill geometry that deformed the least, respectively, was Essentium PLA Gray and "grid". Standard retractors without intervention failed at 95 N +/- 2.4 N. Annealed retractors failed at 127.3 N +/- 10 N. Autoclave only retractors failed at 15.7 N +/- 1.4 N. Annealed then autoclaved retractors failed at 19.8 N +/- 3.1 N. Strength-optimized retractors, after the annealing then autoclaving intervention, failed at 164.8 N +/- 12.5 N.

CONCLUSION

For 30 mm cubes, the 3D printing material and infill geometry that deformed the least, respectively, was Essentium PLA and "grid". Hot water-bath annealing results in increased 3D printed model strength, however autoclaving 3D prints markedly diminishes strength. Strength-optimized 3D printed PLA Army-Navy retractors overcome the strength limitation due to autoclaving.

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.

Customized Novel Design of 3D Printed Pregabalin Tablets for Intra-Gastric Floating and Controlled Release Using Fused Deposition Modeling

Three-dimensional (3D) printing has been recently employed in the design and formulation of various dosage forms with the aim of on-demand manufacturing and personalized medicine. In this study, we formulated a floating sustained release system using fused deposition modeling (FDM). Filaments were prepared using hypromellose acetate succinate (HPMCAS), polyethylene glycol (PEG 400) and pregabalin as the active ingredient. Cylindrical tablets with infill percentages of 25%, 50% and 75% were designed and printed with the FDM printer. An optimized formulation (F6) was designed with a closed bottom layer and a partially opened top layer. Filaments and tablets were characterized by means of fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), X-ray powder diffraction (XRPD), and thermogravimetric analysis (TGA). The results show that the processing condition did not have a significant effect on the stability of the drug and the crystallinity of the drug remained even after printing. A dissolution study revealed that drug release is faster in an open system with low infill percentage compared to closed systems and open systems with a high infill ratio. The optimized formulation (F6) with partially opened top layer showed zero-order drug release. The results show that FDM printing is suitable for the formulation of floating dosage form with the desired drug release profile.

The Use of Augmented Reality Technology in Medical Specimen Museum Tours

Human anatomical specimen museums are commonly used by medical, nursing, and paramedical students. Through dissection and prosection, the specimens housed in these museums allow students to appreciate the complex relationships of organs and structures in more detail than textbooks could provide. However, it may be difficult for students, particularly novices, to identify the various parts of these anatomical structures without additional explanations from a docent or supplemental illustrations. Recently, augmented reality (AR) has been used in many museum exhibits to display virtual objects in videos captured from the real world. This technology can significantly enhance the learning experience. In this study, three AR-based support systems for tours in medical specimen museums were developed, and their usability and effectiveness for learning were examined. The first system was constructed using an AR marker. This system could display virtual label information for specimens by capturing AR markers using a tablet camera. Individual AR markers were required for all specimens, but their presence in and on the prosected specimens could also be obtrusive. The second system was developed to set the specimen image itself as an image marker, as most specimens were displayed in cross section. Visitors could then obtain the label information presented by AR without any markers intruding on the display or anatomical specimens. The third system was comprised of a head-mounted display combined with a natural click interface. The system could provide visitors with an environment for the natural manipulation of virtual objects with future scalability.

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.

Cytoskeletal and Actin-Based Polymerization Motors and Their Role in Minimal Cell Design

Life implies motion. In cells, protein-based active molecular machines drive cell locomotion and intracellular transport, control cell shape, segregate genetic material, and split a cell in two parts. Key players among molecular machines driving these various cell functions are the cytoskeleton and motor proteins that convert chemical bound energy into mechanical work. Findings over the last decades in the field of in vitro reconstitutions of cytoskeletal and motor proteins have elucidated mechanistic details of these active protein systems. For example, a complex spatial and temporal interplay between the cytoskeleton and motor proteins is responsible for the translation of chemically bound energy into (directed) movement and force generation, which eventually governs the emergence of complex cellular functions. Understanding these mechanisms and the design principles of the cytoskeleton and motor proteins builds the basis for mimicking fundamental life processes. Here, a brief overview of actin, prokaryotic actin analogs, and motor proteins and their potential role in the design of a minimal cell from the bottom-up is provided.

3D Printing Technology in Design of Pharmaceutical Products

Background:

Three-dimensional printing (3DP) is a novel technology for fabrication of personalized medicine. As of late, FDA affirmed 3D printed tranquilize item in August 2015, which is characteristic of another section of Pharmaceutical assembling. 3DP incorporates a wide range of assembling procedures, which are altogether founded on computer-aided design (CAD), and controlled deposition of materials (layer-by-layer) to make freestyle geometries. Conventionally, many pharmaceutical processes like compressed tablet have been used from many years for the development of tablet with established regulatory pathways. But this simple process is outdated in terms of process competence and manufacturing flexibility (design space). 3DP is a new technology for the creation of plan, proving to be superior for complex products, customized items and items made on-request. It creates new opportunities for improving efficacy, safety, and convenience of medicines.

Method:

There are many of the 3D printing technology used for the development of personalized medicine on demand for better treatment like 3D powder direct printing technology, fused-filament 3D printing, 3D extrusion printer, piezoelectric inkjet printer, fused deposition 3D printing, 3D printer, ink-jet printer, micro-drop inkjet 3DP, thermal inkjet printer, multi-nozzle 3D printer, stereolithographic 3D printer.

Result:

This review highlights features how item and process comprehension can encourage the improvement of a control technique for various 3D printing strategies.

Conclusion:

It is concluded that the 3D printing technology is a novel potential for manufacturing of personalized dose medicines, due to better patient compliance which can be prepared when needed.

Complex formulations, simple techniques: Can 3D printing technology be the Midas touch in pharmaceutical industry?

3D printing is a method of rapid prototyping and manufacturing in which materials are deposited onto one another in layers to produce a three-dimensional object. Although 3D printing was developed in the 1980s and the technology has found widespread industrial applications for production from automotive parts to machine tools, its application in pharmaceutical area is still limited. However, the potential of 3D printing in the pharmaceutical industry is now being recognized. The ability of 3D printing to produce medications to exact specifications tailored to the needs of individual patients has indicated the possibility of developing personalized medicines. The technology allows dosage forms to be precisely printed in various shapes, sizes and textures that are difficult to produce using traditional techniques. However, there are various challenges associated with the proper application of 3D printing in the pharmaceutical sector which should be overcome to exploit the scope of this technology. In this review, an overview is provided on the various 3D printing technologies used in fabrication of complex dosage forms along with their feasibility and limitations.

Generating vascular conduits: from tissue engineering to three-dimensional bioprinting

Vascular disease - including coronary artery disease, carotid artery disease, and peripheral vascular disease - is a leading cause of morbidity and mortality worldwide. The standard of care for restoring patency or bypassing occluded vessels involves using autologous grafts, typically the saphenous veins or internal mammary arteries. Yet, many patients who need life- or limb-saving procedures have poor outcomes, and a third of patients who need vascular intervention have multivessel disease and therefore lack appropriate vasculature to harvest autologous grafts from. Given the steady increase in the prevalence of vascular disease, there is great need for grafts with the biological and mechanical properties of native vessels that can be used as vascular conduits. In this review, we present an overview of methods that have been employed to generate suitable vascular conduits, focusing on the advances in tissue engineering methods and current three-dimensional (3D) bioprinting methods. Tissue-engineered vascular grafts have been fabricated using a variety of approaches such as using preexisting scaffolds and acellular organic compounds. We also give an extensive overview of the novel use of 3D bioprinting as means of generating new vascular conduits. Different strategies have been employed in bioprinting, and the use of cell-based inks to create de novo structures offers a promising solution to bridge the gap of paucity of optimal donor grafts. Lastly, we provide a glimpse of our work to create scaffold-free, bioreactor-free, 3D bioprinted vessels from a combination of rat vascular smooth muscle cells and fibroblasts that remain patent and retain the tensile and mechanical strength of native vessels.

Three-dimensional (3D) printing and its applications for aortic diseases

Three-dimensional (3D) printing is a process which generates prototypes from virtual objects in computer-aided design (CAD) software. Since 3D printing enables the creation of customized objects, it is a rapidly expanding field in an age of personalized medicine. We discuss the use of 3D printing in surgical planning, training, and creation of devices for the treatment of aortic diseases. 3D printing can provide operators with a hands-on model to interact with complex anatomy, enable prototyping of devices for implantation based upon anatomy, or even provide pre-procedural simulation. Potential exists to expand upon current uses of 3D printing to create personalized implantable devices such as grafts. Future studies should aim to demonstrate the impact of 3D printing on outcomes to make this technology more accessible to patients with complex aortic diseases.

Patient-specific three-dimensional printing for pre-surgical planning in hepatocellular carcinoma treatment

Background

Recently, three-dimensional (3D) printing has shown great interest in medicine, and 3D printed models may be rendered as part of the pre-surgical planning process in order to better understand the complexities of an individual's anatomy. The aim of this study is to investigate the feasibility of utilising 3D printed liver models as clinical tools in pre-operative planning for resectable hepatocellular carcinoma (HCC) lesions.

Methods

High-resolution contrast-enhanced computed tomography (CT) images were acquired and utilized to generate a patient-specific 3D printed liver model. Hepatic structures were segmented and edited to produce a printable model delineating intrahepatic anatomy and a resectable HCC lesion. Quantitative assessment of 3D model accuracy compared measurements of critical anatomical landmarks acquired from the original CT images, standard tessellation language (STL) files, and the 3D printed liver model. Comparative analysis of surveys completed by two radiologists investigated the clinical value of 3D printed liver models in radiology. The application of utilizing 3D printed liver models as tools in surgical planning for resectable HCC lesions was evaluated through kappa analysis of questionnaires completed by two abdominal surgeons.

Results

A scaled down multi-material 3D liver model delineating patient-specific hepatic anatomy and pathology was produced, requiring a total production time of 25.25 hours and costing a total of AUD $1,250. A discrepancy was found in the total mean of measurements at each stage of production, with a total mean of 18.28±9.31 mm for measurements acquired from the original CT data, 15.63±8.06 mm for the STL files, and 14.47±7.71 mm for the 3D printed liver model. The 3D liver model did not enhance the radiologists' perception of patient-specific anatomy or pathology. Kappa analysis of the surgeon's responses to survey questions yielded a percentage agreement of 80%, and a κ value of 0.38 (P=0.24) indicating fair agreement.

Conclusions

Study outcomes indicate that there is minimal value in utilizing the 3D printed models in diagnostic radiology. The potential usefulness of utilizing patient-specific 3D printed liver models as tools in surgical planning and intraoperative guidance for HCC treatment is verified. However, the feasibility of this application is currently challenged by identified limitations in 3D model production, including the cost and time required for model production, and inaccuracies potentially introduced at each stage of model fabrication.