Clinical efficacy and effectiveness of 3D printing: a systematic review

Investigation of the Biocidal Performance of Multi-Functional Resin/Copper Nanocomposites with Superior Mechanical Response in SLA 3D Printing

Metals, such as silver, gold, and copper are known for their biocidal properties, mimicking the host defense peptides (HDPs) of the immune system. Developing materials with such properties has great importance in medicine, especially when combined with 3D printing technology, which is an additional asset for various applications. In this work, copper nanoparticles were used as filler in stereolithography (SLA) ultraviolet (UV) cured commercial resin to induce such biocidal properties in the material. The nanocomposites developed featured enhanced mechanical responses when compared with the neat material. The prepared nanocomposites were employed to manufacture specimens with the SLA process, to be tested for their mechanical response according to international standards. The process followed was evaluated with Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), energy-dispersive X-ray spectroscopy (EDS), and thermogravimetric analysis (TGA). The antibacterial activity of the fabricated nanocomposites was evaluated using the agar-well diffusion method. Results showed enhanced mechanical performance of approximately 33.7% in the tensile tests for the nanocomposites filled with 1.0 wt.%. ratios, when compared to the neat matrix material, while this loading showed sufficient antibacterial performance when compared to lower filler loadings, providing an added value for the fabrication of effective nanocomposites in medical applications with the SLA process.

Three-Dimensional Printed Models for Preoperative Planning and Surgical Treatment of Chest Wall Disease: A Systematic Review

Introduction: In chest wall reconstruction, the main objectives are the restoration of the chest wall integrity, function, and aesthetic, which is often achieved with the placement of implants. We aimed to evaluate whether 3D printed models can be useful for preoperative planning and surgical treatment in chest wall reconstruction to improve the outcome of the surgery and to reduce the rate of complications. Methods: We conducted a systematic review of literature using PubMed, Scopus, Embase, and Google Scholar databases until 8 November 2021 with the following keywords: (“3D printing” or “rapid prototyping” or “three-dimensional printing” or “bioprinting”) and (“chest wall” or “rib” or “sternum” or “ribcage” or “pectus excavatum”). Results were then manually screened by two independent authors to select studies relevant to 3D printing application in chest wall reconstruction. The primary outcome was morphological correction, and secondary outcomes were changes in operating time and procedure-related complication rate. Results: Eight articles were included in our review. Four studies were related to pectus excavatum correction, two studies were related to rib fracture stabilization, and two studies were related to chest wall tumor resection and reconstruction. Seven studies reported 3D printing of a thorax model or template implants for preoperative planning and implant modeling, and one study reported 3D printing of a PEEK prosthesis for direct implantation. Four studies reported comparison with a conventionally treated control group, and three of them detected a shorter operative time in the 3D printing model-assisted group. Satisfactory morphological correction was reported in all studies, and six studies reported a good implant fitting with minimal need for intraoperative adjustments. There were no major intraoperative or postoperative complications in any of the studies. Conclusions: The use of 3D printing models in chest wall reconstruction seems to be helpful for the production of personalized implants, reducing intraoperative adjustments. Results of morphological correction and postoperative recovery after the 3D printing-assisted surgery were satisfactory in all studies with a low rate of complication. Our literature review suggests good results regarding prosthesis fitting, accuracy of surgical planning, and reduction in operative time in 3D printing-assisted procedures, although more evidence is needed to prove this observation.

Additive Manufacturing for Neurosurgery: Digital Light Processing of Individualized Patient-Specific Cerebral Aneurysms

This study aims at demonstrating the feasibility of reproducing individualized patient-specific three-dimensional models of cerebral aneurysms by using the direct light processing (DLP) 3D printing technique in a low-time and inexpensive way. Such models were used to help neurosurgeons understand the anatomy of the aneurysms together with the surrounding vessels and their relationships, providing, therefore, a tangible supporting tool with which to train and plan surgical operations. The starting 3D models were obtained by processing the computed tomography angiographies and the digital subtraction angiographies of three patients. Then, a 3D DLP printer was used to print the models, and, if acceptable, on the basis of the neurosurgeon’s opinion, they were used for the planning of the neurosurgery operation and patient information. All the models were printed within three hours, providing a comprehensive representation of the cerebral aneurysms and the surrounding structures and improving the understanding of their anatomy and simplifying the planning of the surgical operation.

Application of 3D printing in the treatment of appendicular skeleton fractures: Systematic review and meta-analysis

The objective of this study is to evaluate, through a systematic review of the scientific literature and meta-analysis, the applications of three-dimensional (3D) printing in the surgical treatment of complex fractures of the appendicular skeleton, mainly in terms of effectiveness and safety. A systematic review of the scientific literature was conducted in MEDLINE (PubMed) and the Cochrane Library combining different keywords. A specific methodological assessment scale was developed and applied to included papers. Ten studies were included; all of them were controlled trials, except for one retrospective observational cohort study. We observed statistically significant differences between the group that used 3D printing and the control group in terms of reduction in surgical time, reduction in the volume of blood lost during surgery and reduction in the number of intraoperative fluoroscopies, in favor of the 3D printing group. No statistically significant differences were observed in terms of fracture healing time, postoperative joint function, or postoperative complications. Meta-analysis revealed more favorable results for 3D-printing compared with conventional surgery, with the greatest difference observed for the number of intraoperative fluoroscopies. 3D printing might be considered effective and safe in the surgical treatment of anatomically complex appendicular skeleton fractures, in terms of reducing surgical time, lost blood volume, and radiation exposure of surgeons and patients.

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.

Facilitating Student Understanding through Incorporating Digital Images and 3D-Printed Models in a Human Anatomy Course

Combining classical educational methods with interactive three-dimensional (3D) visualization technology has great power to support and provide students with a unique opportunity to use them in the study process, training, and/or simulation of different medical procedures in terms of a Human Anatomy course. In 2016, Rīga Stradiņš University (RSU) offered students the 3D Virtual Dissection Table “Anatomage” with possibilities of virtual dissection and digital images at the Department of Morphology. The first 3D models were printed in 2018 and a new printing course was integrated into the Human Anatomy curriculum. This study was focused on the interaction of students with digital images, 3D models, and their combinations. The incorporation and use of digital technologies offered students great tools for their creativity, increased the level of knowledge and skills, and gave them a possibility to study human body structures and to develop relationships between basic and clinical studies.

A review and guide to creating patient specific 3D printed anatomical models from MRI for benign gynecologic surgery

Background

Patient specific three-dimensional (3D) models can be derived from two-dimensional medical images, such as magnetic resonance (MR) images. 3D models have been shown to improve anatomical comprehension by providing more accurate assessments of anatomical volumes and better perspectives of structural orientations relative to adjacent structures. The clinical benefit of using patient specific 3D printed models have been highlighted in the fields of orthopaedics, cardiothoracics, and neurosurgery for the purpose of pre-surgical planning. However, reports on the clinical use of 3D printed models in the field of gynecology are limited.

Main text

This article aims to provide a brief overview of the principles of 3D printing and the steps required to derive patient-specific, anatomically accurate 3D printed models of gynecologic anatomy from MR images. Examples of 3D printed models for uterine fibroids and endometriosis are presented as well as a discussion on the barriers to clinical uptake and the future directions for 3D printing in the field of gynecological surgery.

Conclusion

Successful gynecologic surgery requires a thorough understanding of the patient’s anatomy and burden of disease. Future use of patient specific 3D printed models is encouraged so the clinical benefit can be better understood and evidence to support their use in standard of care can be provided.

3D-Printing of Drug-Eluting Implants: An Overview of the Current Developments Described in the Literature

The usage of 3D-printing for drug-eluting implants combines the advantages of a targeted local drug therapy over longer periods of time at the precise location of the disease with a manufacturing technique that easily allows modifications of the implant shape to comply with the individual needs of each patient. Research until now has been focused on several aspects of this topic such as 3D-printing with different materials or printing techniques to achieve implants with different shapes, mechanical properties or release profiles. This review is intended to provide an overview of the developments currently described in the literature. The topic is very multifaceted and several of the investigated aspects are not related to just one type of application. Consequently, this overview deals with the topic of 3D-printed drug-eluting implants in the application fields of stents and catheters, gynecological devices, devices for bone treatment and surgical screws, antitumoral devices and surgical meshes, as well as other devices with either simple or complex geometry. Overall, the current findings highlight the great potential of the manufacturing of drug-eluting implants via 3D-printing technology for advanced individualized medicine despite remaining challenges such as the regulatory approval of individualized implants.

Diving into 3D (bio)printing: A revolutionary tool to customize the production of drug and cell-based systems for skin delivery

The incorporation of 3D printing technologies in the pharmaceutical industry can revolutionize its R&D, by providing a simple and rapid method to produce tailored one-off batches, each with customized dosages, different compounds, shapes, sizes, and adjusted release rates. Particularly, this type of technology can be advantageous for the development of topical and transdermal drug delivery systems, including patches and microneedles. The use of both systems as drug carriers offers advantages over the oral administration, but the possibility of skin irritation and sensitization, and the high production costs, may hinder the expansion of this market. In this context, 3D printing, a high-resolution technique, allows the design of high quality, personalized, complex and sophisticated structures, thus reducing the production costs and improving the patient compliance. This review covers the 3D printing concept and discusses the relevance of this technology to the pharmaceutical industry, with a special focus on the development of topical and transdermal products - patches and microneedles. The potential of 3D bioprinting for skin applications is also presented, highlighting the development of patch-like skin constructs for wound and burn treatment, and skin equivalents for in vitro research and drug development. Several recent studies were selected to support the relevance of the subjects addressed herein. Additionally, the limitations of these printing technologies are discussed, including regulatory, quality and safety issues.

Review of Bioprinting in Regenerative Medicine: Naturally Derived Bioinks and Stem Cells

Regenerative medicine offers the potential to repair or substitute defective tissues by constructing active tissues to address the scarcity and demands for transplantation. The method of forming 3D constructs made up of biomaterials, cells, and biomolecules is called bioprinting. Bioprinting of stem cells provides the ability to reliably recreate tissues, organs, and microenvironments to be used in regenerative medicine. 3D bioprinting is a technique that uses several biomaterials and cells to tailor a structure with clinically relevant geometries and sizes. This technique's promise is demonstrated by 3D bioprinted tissues, including skin, bone, cartilage, and cardiovascular, corneal, hepatic, and adipose tissues. Several bioprinting methods have been combined with stem cells to effectively produce tissue models, including adult stem cells, embryonic stem cells (ESCs), induced pluripotent stem cells (iPSCs), and differentiation techniques. In this review, technological challenges of printed stem cells using prevalent naturally derived bioinks (e.g., carbohydrate polymers and protein-based polymers, peptides, and decellularized extracellular matrix), recent advancements, leading companies, and clinical trials in the field of 3D bioprinting are delineated.

The current progress and critical analysis of three-dimensional scanning and three-dimensional printing applications in breast surgery

Background

Several attempts have been made to develop a tool capable of evaluating breast shape and volume to aid surgical planning and outcome assessment. More recently, newer technologies such as three-dimensional (3D) scanning and 3D printing have been applied in breast assessment. The aim of this study was to review the literature to assess the applicability of 3D scanning and 3D printing in breast surgery.

Methods

A literature search was carried on PubMed, Google Scholar and OVID from January 2000 to December 2019 using the keywords ‘3D’, ‘Three-dimensional’, ‘Three/four dimensions’ and ‘Breast’.

Results

A total of 6564 articles were identified initially; the abstracts of 1846 articles were scanned, and 81 articles met the inclusion criteria and were included in this review. Articles were reviewed and classified according to their aims, study subjects, the software and hardware used, main outcomes and major limitations.

Conclusions

These technologies are fast and easy to use, however, high costs, long processing times and the need for training might limit their application. To incorporate these technologies into standard healthcare, their efficacy and effectiveness must be demonstrated through multiple and rigorous clinical trials.

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.

Comparison in clinical performance of surgical guides for mandibular surgery and temporomandibular joint implants fabricated by additive manufacturing techniques

Additive manufacturing (AM) offers great design freedom that enables objects with desired unique and complex geometry and topology to be readily and cost-effectively fabricated. The overall benefits of AM are well known, such as increased material and resource efficiency, enhanced design and production flexibility, the ability to create porous structures and on-demand manufacturing. When AM is applied to medical devices, these benefits are naturally assumed. However, hard clinical evidence collected from clinical trials and studies seems to be lacking and, as a result, systematic assessment is yet difficult. In the present work, we have reviewed 23 studies on the clinical use of AM patient-specific surgical guides (PSGs) for the mandible surgeries (n = 17) and temporomandibular joint (TMJ) patient-specific implants (PSIs) (n = 6) with respect to expected clinical outcomes. It is concluded that the data published on these AM medical devices are often lacking in comprehensive evaluation of clinical outcomes. A complete set of clinical data, including those on time management, costs, clinical outcomes, range of motion, accuracy of the placement with respect to the pre-operative planning, and extra complications, as well as manufacturing data are needed to demonstrate the real benefits gained from applying AM to these medical devices and to satisfy regulatory requirements.

The Use of 3D Printers in Medical Education with a Focus on Bone Pathology

The purpose of this study was to determine the feasibility and effectiveness of incorporating three-dimensional (3D)-printed models into pathology lectures. 3D models of an osteochondroma and an osteosarcoma were printed from a digital model and MRI, respectively, using both stereolithographic and fused-deposition modeling printing techniques. First year medical students with no prior instruction on bone tumors were randomized into two groups: a control group with 2D images and an experimental group with 3D models. The students viewed a pre-recorded lecture about bone tumors, supplemented with handling either 2D images or 3D models of an osteochondroma and osteosarcoma. Performance on pre- and post-activity assessments was compared to evaluate educational effectiveness. Printing 3D models of bone tumors was relatively simple and inexpensive. Assessment data showed that although both groups had improved performance and greater confidence post-lecture, those that handled the 3D models had a more favorable experience than those with the 2D images. This study demonstrates 3D-printed models can be incorporated into a pathology lecture and can positively influence teaching-learning outcomes.

Additive 3-dimensional printing as a novel tool for pre- and postsurgical evaluation and patient education: A clinical case series

BACKGROUND AND OVERVIEW

In contrast to subtractive 3-dimensional (3D) techniques synonymous with computer-aided design and computer-aided manufacturing, rapid progress in additive 3D printing, especially fused filament fabrication or fused deposition modeling, can change the practice of dentistry.

CASE DESCRIPTION

In this article, the authors outline the digital workflow for fused filament fabrication and fused deposition modeling 3D printing that involves converting a Digital Imaging and Communications in Medicine file (scan or radiograph) to a printable Standard Triangle Language file that can be modified (additions or manipulations) using a readily accessible software for 3D printing. The authors also present a clinical case series showing various applications for this technique, including clinician and patient education, treatment planning, and posttreatment evaluations.

CONCLUSIONS AND PRACTICAL IMPLICATIONS

The low cost and simple workflow of additive 3D printing has potential to improve precision and efficiency in clinical dentistry for both academic and private practices.

Application of 3-dimensional printing technology combined with guide plates for thoracic spinal tuberculosis

BACKGROUND

To explore the accuracy and security of 3-dimensional (3D) printing technology combined with guide plates in the preoperative planning of thoracic tuberculosis and the auxiliary placement of pedicle screws during the operation.

METHODS

Retrospective analysis was performed on the data of 60 cases of thoracic tuberculosis patients treated with 1-stage posterior debridement, bone graft fusion, and pedicle screw internal fixation in the Department of Orthopedics, Zhejiang Chinese Medicine and Western Medicine Integrated Hospital from March 2017 to February 2019. There were 31 males and 29 females; age: 41 to 52 years old, with an average of (46.6 ± 2.0) years old. According to whether 3D printing personalized external guide plates are used or not, they are divided into 2 groups: 30 cases in 3D printing group (observation group), and 30 cases in pedicle screw placement group (control group). A 1:1 solid model of thoracic spinal tuberculosis and personalized pedicle guide plates was created using the 3D printing technology combined with guide plates in the observation group. Stability and accuracy tests were carried out in vitro and in vivo. 30 patients in the control group used conventional nail placement with bare hands. The amount of blood loss, the number of fluoroscopy, the operation time, and the occurrence of adverse reactions related to nail placement were recorded. After the operation, the patients were scanned by computed tomography to observe the screw position and grade the screw position to evaluate the accuracy of the navigation template. All patients were followed up for more than 1 year. Visual Analogue Scale scores, erythrocyte sedimentation rate, and C-reactive protein were evaluated before surgery, 6 months after surgery, and 12 months after surgery.

RESULTS

Sixty patients were followed up for 6 to 12 months after surgery. One hundred seventy-five and 177 screws were placed in the 3D printing group and the free-hand placement group, respectively. The rate of screw penetration was only 1.14% in the 3D-printed group (all 3 screws were grade 1) and 6.78% in the free-hand nail placement group (12 screws, 9 screws were grade 1 and 3 screws were grade 2). The difference was statistically significant (P = .047). The operation time of the 3D printing group ([137.67 ± 9.39] minutes), the cumulative number of intraoperative fluoroscopy ([4.67 ± 1.03] times), and the amount of intraoperative blood loss ([599.33 ± 83.37] mL) were significantly less than those in the manual nail placement group ([170.00 ± 20.48] minutes, [9.38 ± 1.76] times, [674.6 ± 83.61] mL). The differences were statistically significant (P < .05). There was no significant difference in VAS score and Oswestry disability index score between the 2 groups of patients before operation, 3 and 6 months after operation (P > .05).

CONCLUSION

The 3D printing technology combined with guide plate is used in thoracic spinal tuberculosis surgery to effectively reduce the amount of bleeding, shorten the operation time, and increase the safety and accuracy of nail placement.

Pediatric surgery is academic by essence: The French perspective

This article offers a personal view on academic pediatric surgery from France. The author shares reflections and looks to the future of the speciality with the desire to encourage and embrace research and innovation. National and international collaboration is emphasized. Surgeons must seize these opportunities to become the next generation of academic pediatric surgeons in France.

Three-Dimensional Technology Applications in Maxillofacial Reconstructive Surgery: Current Surgical Implications

Defects in the oral and maxillofacial (OMF) complex may lead to functional and esthetic impairment, aspiration, speech difficulty, and reduced quality of life. Reconstruction of such defects is considered one of the most challenging procedures in head and neck surgery. Transfer of different auto-grafts is still considered as the “gold standard” of regenerative and reconstructive procedures for OMF defects. However, harvesting of these grafts can lead to many complications including donor-site morbidity, extending of surgical time, incomplete healing of the donor site and others. Three-dimensional (3D) printing technology is an innovative technique that allows the fabrication of personalized implants and scaffolds that fit the precise anatomy of an individual’s defect and, therefore, has attracted significant attention during the last few decades, especially among head and neck surgeons. Here we discuss the most relevant applications of the 3D printing technology in the oral and maxillofacial surgery field. We further show different clinical examples of patients who were treated at our institute using the 3D technology and discuss the indications, different technologies, complications, and their clinical outcomes. We demonstrate that 3D technology may provide a powerful tool used for reconstruction of various OMF defects, enabling optimal clinical results in the suitable cases.

Should hospitals invest in customised on-demand 3D printing for surgeries?

Purpose

The purpose of this research is to (1) analyse the effect of customised on-demand 3DP on surgical flow time, its variability and clinical outcomes (2) provide a framework for hospitals to decide whether to invest in 3DP or to outsource.

Design/methodology/approach

The research design included interviews, workshops and field visits. Design science approach was used to analyse the impact of the 3D printing (3DP) interventions on specific outcomes and to develop frameworks for hospitals to invest in 3DP, which were validated through further interviews with stakeholders.

Findings

Evidence from this research shows that deploying customised on-demand 3DP can reduce surgical flow time and its variability while improving clinical outcomes. Such outcomes are obtained due to rapid development of the anatomical model and surgical guides along with precise cutting during surgery.

Research limitations/implications

We outline multiple opportunities for research on supply chain design and performance assessment for surgical 3DP. Further empirical research is needed to validate the results.

Practical implications

The decision to implement 3DP in hospitals or to engage service providers will require careful analysis of complexity, demand, lead-time criticality and a hospital's own objectives. Hospitals can follow different paths in adopting 3DP for surgeries depending on their context.

Originality/value

The operations and supply chain management community has researched on-demand distributed manufacturing for multiple industries. To the best of our knowledge, this is the first paper on customised on-demand 3DP for surgeries.

Experiment of Mechanical Properties of a Customized Distractor Based on 3D Printing Technology

This study aimed to design and fabricate a customized distractor based on 3D printing technology and compare its mechanical properties with conventional distractor. The investigators designed and implemented a study composed of conventional and customized distractors. The design of customized distractor was based on the specification of conventional mandibular distractors and was fabricated using selective laser melting (SLM) technology. The same type of conventional distractors served as control group. Vickers-hardness test, three-point bending test and welding strength test were carried out for the conventional and customized distractor respectively and data was analyzed with t test using SPSS13.0 software package. The sample was composed of 18 distractors grouped as follows: customized distractor (n = 9) and conventional distractor (n = 9). The customized distractor showed better result than the conventional distractor in mechanical property tests, with statistically significant differences in Vickers-hardness and maximum load (P < 0.05), and no significant differences in yield strength and welding strength (P > 0.05). The results of this study suggest indicated that compared to the conventional distractor, the customized distractor had better mechanical properties and could be used in maxillofacial distraction osteogenesis.

The role of 3D printed models in the teaching of human anatomy: a systematic review and meta-analysis

BACKGROUND

Three-dimensional (3D) printing is an emerging technology widely used in medical education. However, its role in the teaching of human anatomy needs further evaluation.

METHODS

PubMed, Embase, EBSCO, SpringerLink, and Nature databases were searched systematically for studies published from January 2011 to April 2020 in the English language. GRADEprofiler software was used to evaluate the quality of literature. In this study, a meta-analysis of continuous and binary data was conducted. Both descriptive and statistical analyses were used.

RESULTS

Comparing the post-training tests in neuroanatomy, cardiac anatomy, and abdominal anatomy, the standardized mean difference (SMD) of the 3D group and the conventional group were 1.27, 0.37, and 2.01, respectively (p < 0.05). For 3D vs. cadaver and 3D vs. 2D, the SMD were 0.69 and 1.05, respectively (p < 0.05). For answering time, the SMD of the 3D group vs. conventional group was - 0.61 (P < 0.05). For 3D print usefulness, RR = 2.29(P < 0.05). Five of the six studies showed that satisfaction of the 3D group was higher than that of the conventional group. Two studies showed that accuracy of answering questions in the 3D group was higher than that in the conventional group.

CONCLUSIONS

Compared with students in the conventional group, those in the 3D printing group had advantages in accuracy and answering time. In the test of anatomical knowledge, the test results of students in the 3D group were not inferior (higher or equal) to those in the conventional group. The post-training test results of the 3D group were higher than those in the cadaver or 2D group. More students in the 3D printing group were satisfied with their learning compared with the conventional group. The results could be influenced by the quality of the randomized controlled trials. In a framework of ethical rigor, the application of the 3D printing model in human anatomy teaching is expected to grow further.

Next-generation tissue-engineered heart valves with repair, remodelling and regeneration capacity

Valvular heart disease is a major cause of morbidity and mortality worldwide. Surgical valve repair or replacement has been the standard of care for patients with valvular heart disease for many decades, but transcatheter heart valve therapy has revolutionized the field in the past 15 years. However, despite the tremendous technical evolution of transcatheter heart valves, to date, the clinically available heart valve prostheses for surgical and transcatheter replacement have considerable limitations. The design of next-generation tissue-engineered heart valves (TEHVs) with repair, remodelling and regenerative capacity can address these limitations, and TEHVs could become a promising therapeutic alternative for patients with valvular disease. In this Review, we present a comprehensive overview of current clinically adopted heart valve replacement options, with a focus on transcatheter prostheses. We discuss the various concepts of heart valve tissue engineering underlying the design of next-generation TEHVs, focusing on off-the-shelf technologies. We also summarize the latest preclinical and clinical evidence for the use of these TEHVs and describe the current scientific, regulatory and clinical challenges associated with the safe and broad clinical translation of this technology.

A Review on 3D-Printed Templates for Precontouring Fixation Plates in Orthopedic Surgery

This paper is a systematic review of the literature on 3D-printed anatomical replicas used as templates for precontouring the fixation plates in orthopedic surgery. Embase, PubMed, Cochrane, Scopus and Springer databases were consulted for information on design study, fracture anatomical location, number of patients, surgical technique, virtual modeling approach and 3D printing process. The initial search provided a total of 496 records. After removing the duplicates, the title and abstract screening, and applying exclusion criteria and citations searching, 30 papers were declared eligible and included in the final synthesis. Seven studies were identified as focusing on retrospective non-randomized series of clinical cases, while two papers presented randomized case control studies. Two main approaches were highlighted in developing 3D-printed anatomical models for precontouring fixation plates: (a.) medical reconstruction, virtual planning and fracture reduction followed by 3D printing the model; (b.) medical reconstruction followed by 3D printing the model of the mirrored uninjured side. Revised studies reported advantages such as surgical time and blood loss reduction, while the reduction quality is similar with that of the conventional surgery. During the last couple of years there was an increase in the number of studies focused on precontouring orthopedic plates using 3D printing technology. Three-dimensionally-printed templates for plate precontouring were mostly used for acetabular fractures. Knowledge on medical virtual modeling and reconstruction is mandatory.

Applications of PLA in modern medicine

Polylactic acid (PLA) is a versatile biopolymer. PLA is synthesized with ease from abundant renewable resources and is biodegradable. PLA has shown promise as a biomaterial in a plethora of healthcare applications such as tissue engineering or regenerative medicine, cardiovascular implants, dental niches, drug carriers, orthopedic interventions, cancer therapy, skin and tendon healing, and lastly medical tools / equipment. PLA has demonstrated instrumental importance as a three-dimensionally (3D) printable biopolymer, which has further been bolstered by its role during the Coronavirus Disease of 2019 (Covid-19) global pandemic. As an abundant filament, PLA has created desperately needed personal protective equipment (PPE) and ventilator modifications. As polymer chemistry continues to advance, so too will the applications and continued efficacy of PLA-based modalities.

Change in the Dominant Side of Chewing as a Serious Factor for Adjusting the Prophylaxis Strategy for Implant-Supported Fixed Dental Prosthesis of Bounded Lateral Defects

OBJECTIVE

 The main purpose of this article is to study the effect of a change in the dominant side of chewing after prosthetics with fixed structures on implants on the main indicators of osseointegration, adaptation to dentures, and the clinical dental status of patients.

MATERIALS AND METHODS

 In a clinical trial, an analysis was made of the adaptation of 64 patients to intraosseous implant-supported fixed dentures and 56 apparently healthy volunteers. The examination complex included determination of the functionally dominant side of chewing, gnathodynamometry and electromyography indicators of masticatory muscles, and radiological osseointegration criteria. The overall treatment outcomes were evaluated using a visual analogue scale and an objective medical questionnaire, "Prognosis of Adaptation to Orthopedic Structures."

RESULTS

 Patients were divided into two subgroups: with a change in the dominant side of chewing after completion of orthopaedic treatment (40 cases) and without a change in the dominant side of chewing (24 cases). In the second subgroup of patients, in contrast to the first subgroup, relatively better indicators of gnathodynamometer and electromyography were observed. So, in the first group, gnathodynamometry indicators on the dominant side were 255.7 N and in the second group 225 N after 9 to 12 months. Electromyography indices amounted to (198.5 μV s) to (166.3 μV s) after 9 to 12 months. Bone density remained at the required level, and overall treatment outcomes were higher. Namely, the compact plate of the alveolar ridge was preserved, and the condition of the bone tissue around the implants testified to stable osseointegration. The participation of surface masticatory muscles in adaptation of patients to intraosseous implant-supported fixed orthopaedic structures and the necessity and importance of changing the dominant chewing side for the general outcomes of orthopaedic treatment have been discussed.

CONCLUSIONS

 It has been established that a change in the functionally dominant chewing side is accompanied by relatively unstable indicators of chewing function, which is combined with increased loads on the installed prostheses during 3 to 6 months of adaptation. This must be taken into account when planning an individual patient adaptation complex for dental orthopaedic structures.

Role of 3D printing for the protection of surgical and critical care professionals in the COVID-19 pandemic

Antecedentes y objetivo

Durante la pandemia de COVID-19 se produce una reducción del material para la protección de los profesionales. La impresión 3D ofrece la posibilidad de compensar la escasez de algunos de los suministros. El objetivo es describir el papel de la impresión 3D en un servicio de salud durante la pandemia de COVID-19, con énfasis en proceso para desarrollar un producto final listo para ser implementado en el entorno clínico.

Materiales y métodos

Se formó un grupo de trabajo entre la administración sanitaria, clínicos y otras instituciones público-privadas de Cantabria coordinado en el Hospital virtual Valdecilla. El proceso incluyó la recepción de las propuestas de impresión, el conocimiento de los recursos de impresión en la región, la selección de los dispositivos, la creación de un equipo para cada proyecto, diseño de prototipos, evaluación y rediseño, fabricación montaje y distribución.

Resultados

Se producen 1) dispositivos que ayudan a prevenir el contagio de los profesionales: pantallas de protección facial (2.400 unidades), accesorios personalizados para fotóforos (20 unidades) y horquillas salvaorejas para mascarillas (1.200 unidades); 2) productos relacionados con la ventilación de pacientes infectados: conectores de sistemas de ventilación no invasiva entre tubuladura y mascarilla; y 3) hisopos oro y nasofaríngeos (7.500 unidades) para la identificación de portadoras del coronavirus con el objetivo de diseñar protocolos de actuación en las área clínicas.

Conclusiones

La impresión 3D es un recurso válido para la producción de material de protección de los profesionales cuyo suministro está reducido durante una pandemia.

Medical 3D Printing Cost-Savings in Orthopedic and Maxillofacial Surgery: Cost Analysis of Operating Room Time Saved with 3D Printed Anatomic Models and Surgical Guides

RATIONALE AND OBJECTIVE

Three-dimensional (3D) printed anatomic models and surgical guides have been shown to reduce operative time. The purpose of this study was to generate an economic analysis of the cost-saving potential of 3D printed anatomic models and surgical guides in orthopedic and maxillofacial surgical applications.

MATERIALS AND METHODS

A targeted literature search identified operating room cost-per-minute and studies that quantified time saved using 3D printed constructs. Studies that reported operative time differences due to 3D printed anatomic models or surgical guides were reviewed and cataloged. A mean of $62 per operating room minute (range of $22-$133 per minute) was used as the reference standard for operating room time cost. Different financial scenarios were modeled with the provided cost-per-minute of operating room time (using high, mean, and low values) and mean time saved using 3D printed constructs.

RESULTS

Seven studies using 3D printed anatomic models in surgical care demonstrated a mean 62 minutes ($3720/case saved from reduced time) of time saved, and 25 studies of 3D printed surgical guides demonstrated a mean 23 minutes time saved ($1488/case saved from reduced time). An estimated 63 models or guides per year (or 1.2/week) were predicted to be the minimum number to breakeven and account for annual fixed costs.

CONCLUSION

Based on the literature-based financial analyses, medical 3D printing appears to reduce operating room costs secondary to shortening procedure times. While resource-intensive, 3D printed constructs used in patients' operative care provides considerable downstream value to health systems.

Problem-driven innovation models for emerging technologies

As a fundamentally resource-intensive endeavour, healthcare innovation can benefit from a problem-based approach. This kind of methodology needs to define the problem by applying a range of well-established techniques, such as ethnographic research, market analysis, and stakeholder exploration. However, no in-depth investigation has taken place on how these techniques interact and relate to one another. As such, an overarching methodology is needed in order to represent, critically assess, and evolve problem-driven, or need-led, innovation approaches. Graph theory provides a useful way by which this can be done. This paper exemplifies how different elements of a problem-first approach to innovation can be graphically represented within a system, in order to provide insights into the processes that support real-world impact for new technologies. By providing a more refined description of the need-led innovation methodology, it is hoped that these models can drive a more evidence-based and empirical mindset within the field to ultimately drive valuable innovations with increased efficiency.

Overview of Minimally Invasive Spine Surgery

Minimally invasive spine surgery (MISS) has continued to evolve over the past few decades, with significant advancements in technology and technical skills. From endonasal cervical approaches to extreme lateral lumbar interbody fusions, MISS has showcased its usefulness across all practice areas of the spine, with unique points of access to avoid pertinent neurovascular structures. Adult spine deformity has also recognized the importance of minimally invasive techniques in its ability to limit complications and to provide adequate sagittal alignment correction and improvements in patients' functional status. Although MISS has continued to make significant progress clinically, consideration must also be given to its economic impact and the learning curve surgeons experience in adding these procedures to their armamentarium. This review examines current innovations in MISS, as well as the economic impact and future directions of the field.

Evaluation of 3D printing costs in surgery: a systematic review

OBJECTIVES

The use of three-dimensional (3D) printing in surgery is expanding and there is a focus on comprehensively evaluating the clinical impact of this technology. However, although additional costs are one of the main limitations to its use, little is known about its economic impact. The purpose of this systematic review is to identify the costs associated with its use and highlight the first quantitative data available.

METHODS

A systematic literature review was conducted in the PubMed and Embase databases and in the National Health Service Economic Evaluation Database (NHS EED) at the University of York. Studies that reported an assessment of the costs associated with the use of 3D printing for surgical application and published between 2009 and 2019, in English or French, were included.

RESULTS

Nine studies were included in our review. Nine types of costs were identified, the three main ones being printing material costs (n = 6), staff costs (n = 3), and operating room costs (n = 3). The printing cost ranged from less than U.S. dollars (USD) 1 to USD 146 (in USD 2019 values) depending on the criteria used to calculate this cost. Three studies evaluated the potential savings generated by the use of 3D printing technology in surgery, based on operating time reduction.

CONCLUSION

This literature review highlights the lack of reliable economic data on 3D printing technology. Nevertheless, this review makes it possible to identify expenditures or items that should be considered in order to carry out more robust studies.

Three-dimensional printing in radiation oncology: A systematic review of the literature

Purpose/objectives

Three‐dimensional (3D) printing is recognized as an effective clinical and educational tool in procedurally intensive specialties. However, it has a nascent role in radiation oncology. The goal of this investigation is to clarify the extent to which 3D printing applications are currently being used in radiation oncology through a systematic review of the literature.

Materials/methods

A search protocol was defined according to preferred reporting items for systematic reviews and meta‐analyses (PRISMA) guidelines. Included articles were evaluated using parameters of interest including: year and country of publication, experimental design, sample size for clinical studies, radiation oncology topic, reported outcomes, and implementation barriers or safety concerns.

Results

One hundred and three publications from 2012 to 2019 met inclusion criteria. The most commonly described 3D printing applications included quality assurance phantoms (26%), brachytherapy applicators (20%), bolus (17%), preclinical animal irradiation (10%), compensators (7%), and immobilization devices (5%). Most studies were preclinical feasibility studies (63%), with few clinical investigations such as case reports or series (13%) or cohort studies (11%). The most common applications evaluated within clinical settings included brachytherapy applicators (44%) and bolus (28%). Sample sizes for clinical investigations were small (median 10, range 1–42). A minority of articles described basic or translational research (11%) and workflow or cost evaluation studies (3%). The number of articles increased over time (P < 0.0001). While outcomes were heterogeneous, most studies reported successful implementation of accurate and cost‐effective 3D printing methods.

Conclusions

Three‐dimensional printing is rapidly growing in radiation oncology and has been implemented effectively in a diverse array of applications. Although the number of 3D printing publications has steadily risen, the majority of current reports are preclinical in nature and the few clinical studies that do exist report on small sample sizes. Further dissemination of ongoing investigations describing the clinical application of developed 3D printing technologies in larger cohorts is warranted.

Effects of Steam Sterilization on 3D Printed Biocompatible Resin Materials for Surgical Guides-An Accuracy Assessment Study

Computer-assisted surgery with three-dimensional (3D) printed surgical guides provides more accurate results than free-hand surgery. Steam sterilization could be one of the factors that affect the dimensions of surgical guide resin materials, leading to inaccuracies during surgeries. The purpose of this study was to evaluate the effects of steam sterilization on the dimensional accuracy of indication-specific hollow cube test bodies, manufactured in-house using Class IIa biocompatible resin materials (proprietary and third-party). To evaluate the pre- and post-sterilization dimensional accuracy, root mean square (RMS) values were calculated. The results indicate that, in all the groups, steam sterilization resulted in an overall linear expansion of the photopolymeric resin material, with an increase in outer dimensions and a decrease in inner dimensions. The effects on the dimensional accuracy of test bodies were not statistically significant in all the groups, except PolyJet Glossy (p > 0.05). The overall pre- and post-sterilization RMS values were below 100 and 200 µm, respectively. The highest accuracies were seen in proprietary resin materials, i.e., PolyJet Glossy and SLA-LT, in pre- and post-sterilization measurements, respectively. The dimensional accuracy of third-party resin materials, i.e., SLA-Luxa and SLA-NextDent, were within a comparable range as proprietary materials and can serve as an economical alternative.

3D Printing for the Clinic: Examining Contemporary Polymeric Biomaterials and Their Clinical Utility

The advent of additive manufacturing offered the potential to revolutionize clinical medicine, particularly with patient-specific implants across a range of tissue types. However, to date, there are very few examples of polymers being used for additive processes in clinical settings. The state of the art with regards to 3D printable polymeric materials being exploited to produce novel clinically relevant implants is discussed here. We focus on the recent advances in the development of implantable, polymeric medical devices and tissue scaffolds without diverging extensively into bioprinting. By introducing the major 3D printing techniques along with current advancements in biomaterials, we hope to provide insight into how these fields may continue to advance while simultaneously reviewing the ongoing work in the field.

Dimensional accuracy of extrusion- and photopolymerization-based 3D printers: In vitro study comparing printed casts

STATEMENT OF PROBLEM

Reliable studies comparing the accuracy of complete-arch casts from 3D printers are scarce.

PURPOSE

The purpose of this in vitro study was to investigate the accuracy of casts printed by using various extrusion- and photopolymerization-based printers.

MATERIAL AND METHODS

A master file was sent to 5 printer manufacturers and distributors to print 37 identical casts. This file consisted of a standardized data set of a maxillary cast in standard tessellation language (STL) format comprising 5 reference points for the measurement of 3 distances that served as reference for all measurements: intermolar width (IMW), intercanine width (ICW), and dental arch length (AL). The digital measurement of the master file obtained by using a surveying software program (Convince Premium 2012) was used as the control. Two extrusion-based (M2 and Ultimaker 2+) and 3 photopolymerization-based printers (Form 2, Asiga MAX UV, and myrev140) were compared. The casts were measured by using a multisensory coordinate measuring machine (O-Inspect 422). The values were then compared with those of the master file. The Mann-Whitney U test and Levene tests were used to determine significant differences in the trueness and precision (accuracy) of the measured distances.

RESULTS

The deviations from the master file at all 3 distances for the included printers ranged between 12 μm and 240 μm (trueness), with an interquartile range (IQR) between 17 μm and 388 μm (precision). Asiga MAX UV displayed the highest accuracy, considering all the distances, and Ultimaker 2+ demonstrated comparable accuracy for shorter distances (IMW and ICW). Although myrev140 operated with high precision, it displayed high deviations from the master file. Similarly, although Form 2 exhibited high IQR, it did not deviate significantly from the master file in the longest range (AL). M2 performed consistently.

CONCLUSIONS

Both extrusion-based and photopolymerization-based printers were accurate. In general, inexpensive printers were no less accurate than more expensive ones.

Rapid Fabrication of Anatomically-Shaped Bone Scaffolds Using Indirect 3D Printing and Perfusion Techniques

Fused deposit modeling (FDM) 3D printing technology cannot generate scaffolds with high porosity while maintaining good integrity, anatomical-surface detail, or high surface area-to-volume ratio (S/V). Solvent casting and particulate leaching (SCPL) technique generates scaffolds with high porosity and high S/V. However, it is challenging to generate complex-shaped scaffolds; and solvent, particle and residual water removal are time consuming. Here we report techniques surmounting these problems, successfully generating a highly porous scaffold with the anatomical-shape characteristics of a human femur by polylactic acid polymer (PLA) and PLA-hydroxyapatite (HA) casting and salt leaching. The mold is water soluble and is easily removable. By perfusing with ethanol, water, and dry air sequentially, the solvent, salt, and residual water were removed 20 fold faster than utilizing conventional methods. The porosities are uniform throughout the femoral shaped scaffold generated with PLA or PLA-HA. Both scaffolds demonstrated good biocompatibility with the pre-osteoblasts (MC3T3-E1) fully attaching to the scaffold within 8 h. The cells demonstrated high viability and proliferation throughout the entire time course. The HA-incorporated scaffolds demonstrated significantly higher compressive strength, modulus and osteoinductivity as evidenced by higher levels of alkaline-phosphatase activity and calcium deposition. When 3D printing a 3D model at 95% porosity or above, our technology preserves integrity and surface detail when compared with FDM-generated scaffolds. Our technology can also generate scaffolds with a 31 fold larger S/V than FDM. We have developed a technology that is a versatile tool in creating personalized, patient-specific bone graft scaffolds efficiently with high porosity, good scaffold integrity, high anatomical-shaped surface detail and large S/V.

The Personalized Shoulder Reconstruction Assisted by 3D Printing Technology After Resection of the Proximal Humerus Tumours

Background

The reverse shoulder arthroplasty (RSA) may be a promising alternative for proximal humerus tumours because of good postoperative shoulder function. However, the conventional reverse shoulder prosthesis can not meet individual needs and RSA has been associated with a relatively high complication rate. Therefore, implant design and surgical reconstruction technique warrant further study.

Methods

Between September 2015 and May 2018, 7 patients were treated via RSA after en-bloc resection of the proximal humerus tumours. A 3D-printed guiding baseplate was used to assist the implant of the 3D-printed glenoid prosthesis; a personalized humerus prosthesis was used to reconstruct the proximal humerus. The functional outcomes were assessed by range of motion (ROM) of the shoulder joint, Musculoskeletal Tumour Society (MSTS) functional score, and Toronto Extremity Salvage Score (TESS). We also analyzed tumour recurrence, metastases, and complications associated with the reconstruction procedure.

Results

All patients were observed for 14 to 36 months, with an average of 23.6 months. At the final follow-up, the mean MSTS score was 85.7% (range, 73.3–93.3%), and the mean TESS score was 90.0% (range, 84.1–95.9%). No instability, infection, scapular notching, loosening or fracture were observed in this series. One patient with GCT suffered from pulmonary metastasis, while one with osteosarcoma died because of pulmonary metastasis.

Conclusion

The 3D-printed guiding baseplate facilitated the accurate implantation of the glenoid prosthesis. The RSA based on a 3D-printed glenoid prosthesis and a personalized custom-made humerus prosthesis significantly improved the shoulder function and decreased the complication rate. Further studies of a larger scale with longer follow-up are required to validate this technology.

From digital world to real life: a robotic approach to the esophagogastric junction with a 3D printed model

Background

Three-dimensional (3D) printing may represent a useful tool to provide, in surgery, a good representation of surgical scenario before surgery, particularly in complex cases. Recently, such a technology has been utilized to plan operative interventions in spinal, neuronal, and cardiac surgeries, but few data are available in the literature about their role in the upper gastrointestinal surgery. The feasibility of this technology has been described in a single case of gastroesophageal reflux disease with complex anatomy due to a markedly tortuous descending aorta.

Methods

A 65-year-old Caucasian woman was referred to our Department complaining heartburn and pyrosis. A chest computed tomography evidenced a tortuous thoracic aorta and consequent compression of the esophagus between the vessel and left atrium. A “dysphagia aortica” has been diagnosed. Thus, surgical treatment of anti-reflux surgery with separation of the distal esophagus from the aorta was planned. To define the strict relationship between the esophagus and the mediastinal organs, a life-size 3D printed model of the esophagus including the proximal stomach, the thoracic aorta and diaphragmatic crus, based on the patient’s CT scan, was manufactured.

Results

The robotic procedure was performed with the da Vinci Surgical System and lasted 175 min. The surgeons had navigational guidance during the procedure since they could consult the 3D electronically superimposed processed images, in a “picture-in-picture” mode, over the surgical field displayed on the monitor as well as on the robotic headset. There was no injury to the surrounding organs and, most importantly, the patient had an uncomplicated postoperative course.

Conclusions

The present clinical report highlights the feasibility, utility and clinical effects of 3D printing technology for preoperative planning and intraoperative guidance in surgery, including the esophagogastric field. However, the lack of published data requires more evidence to assess the effectiveness and safety of this novel surgical-applied printing technology.

Allogenic tooth transplantation using 3D printing: A case report and review of the literature

BACKGROUND

The history of allogenic tooth transplantation can be traced back to the 16th century. Although there have been many successful cases, much needs to be better understood and researched prior to the technique being translated to everyday clinical practice.

CASE SUMMARY

In the present report, we describe a case of allogenic tooth transplantation between a mother and her daughter. The first left maxillary molar of the mother was diagnosed with residual root resorption and needed to be extracted. The 3rd molar of the daughter was used as a donor tooth. Prior to transplantation, a 3D printing system was introduced to fabricate an individualized reamer drill specifically designed utilizing the donor's tooth as a template. The specific design of our 3D printed bur allowed for the recipient site to better match the donor tooth. With the ability to 3D print in layers, even the protuberance of the root can be matched and 3D printed, thereby minimizing unnecessary bone loss.

CONCLUSION

Our study is a pioneering case combining 3D printing with allogenic tooth transplantation, which could be able to minimize unnecessary bone loss and improve the implant stability. This article aims to enhance our understanding of allogenic tooth transplantation and 3D printing, and may potentially lead to tooth transplantation being utilized more frequently - especially since transplantations are so commonly utilized in many other fields of medicine with high success rates.

Implementation of 3D Printing Technology in the Field of Prosthetics: Past, Present, and Future

There is an interesting and long history of prostheses designed for those with upper-limb difference, and yet issues still persist that have not yet been solved. Prosthesis needs for children are particularly complex, due in part to their growth rates. Access to a device can have a significant impact on a child’s psychosocial development. Often, devices supporting both cosmetic form and user function are not accessible to children due to high costs, insurance policies, medical availability, and their perceived durability and complexity of control. These challenges have encouraged a grassroots effort globally to offer a viable solution for the millions of people living with limb difference around the world. The innovative application of 3D printing for customizable and user-specific hardware has led to open-source Do It Yourself “DIY” production of assistive devices, having an incredible impact globally for families with little recourse. This paper examines new research and development of prostheses by the maker community and nonprofit organizations, as well as a novel case study exploring the development of technology and the training methods available. These design efforts are discussed further in the context of the medical regulatory framework in the United States and highlight new associated clinical studies designed to measure the quality of life impact of such devices.

Comparison of 3-Dimensional and Augmented Reality Kidney Models With Conventional Imaging Data in the Preoperative Assessment of Children With Wilms Tumors

IMPORTANCE

Nephron-sparing surgery can be considered in well-defined cases of unilateral and bilateral Wilms tumors, but the surgical procedure can be very challenging for the pediatric surgeon to perform.

OBJECTIVE

To assess the added value of personalized 3-dimensional (3-D) kidney models derived from conventional imaging data to enhance preoperative surgical planning.

DESIGN, SETTING, AND PARTICIPANTS

In a survey study, the conventional imaging data of 10 Dutch children with Wilms tumors were converted to 3-D prints and augmented reality (AR) holograms and a panel of pediatric oncology surgeons (n = 7) assessed the quality of the different imaging methods during preoperative evaluation. Kidney models were created with 3-D printing and AR using a mixed reality headset for visualization.

MAIN OUTCOMES AND MEASURES

Differences in the assessment of 4 anatomical structures (tumor, arteries, veins, and urinary collecting structures) using questionnaires. A Likert scale measured differences between the imaging methods, with scores ranging from 1 (completely disagree) to 5 (completely agree).

RESULTS

Of the 10 patients, 7 were girls, and the mean (SD) age was 3.7 (1.7) years. Compared with conventional imaging, the 3-D print and the AR hologram models were evaluated by the surgeons to be superior for all anatomical structures: tumor (median scores for conventional imaging, 4.07; interquartile range [IQR], 3.62-4.15 vs 3-D print, 4.67; IQR, 4.14-4.71; P = .008 and AR hologram, 4.71; IQR, 4.26-4.75; P = .002); arteries (conventional imaging, 3.62; IQR, 3.43-3.93 vs 3-D print, 4.54; IQR, 4.32-4.71; P = .002 and AR hologram, 4.83; IQR, 4.64-4.86; P < .001), veins (conventional imaging, 3.46; IQR 3.39-3.62 vs 3-D print, 4.50; IQR, 4.39-4.68; P < .001 and AR hologram, 4.83; IQR, 4.71-4.86; P < .001), and urinary collecting structures (conventional imaging, 2.76; IQR, 2.42-3.00 vs 3-D print, 3.86; IQR, 3.64-4.39; P < .001 and AR hologram, 4.00; IQR, 3.93-4.58; P < .001). There were no differences in anatomical assessment between the two 3-D techniques (the 3-D print and AR hologram).

CONCLUSIONS AND RELEVANCE

In this study, the 3-D kidney models were associated with improved anatomical understanding among the surgeons and can be helpful in future preoperative planning of nephron-sparing surgery for Wilms tumors. These models may be considered as a supplementary visualization in clinical care.

The Role of 3D Printing in Medical Applications: A State of the Art

Three-dimensional (3D) printing refers to a number of manufacturing technologies that generate a physical model from digital information. Medical 3D printing was once an ambitious pipe dream. However, time and investment made it real. Nowadays, the 3D printing technology represents a big opportunity to help pharmaceutical and medical companies to create more specific drugs, enabling a rapid production of medical implants, and changing the way that doctors and surgeons plan procedures. Patient-specific 3D-printed anatomical models are becoming increasingly useful tools in today's practice of precision medicine and for personalized treatments. In the future, 3D-printed implantable organs will probably be available, reducing the waiting lists and increasing the number of lives saved. Additive manufacturing for healthcare is still very much a work in progress, but it is already applied in many different ways in medical field that, already reeling under immense pressure with regards to optimal performance and reduced costs, will stand to gain unprecedented benefits from this good-as-gold technology. The goal of this analysis is to demonstrate by a deep research of the 3D-printing applications in medical field the usefulness and drawbacks and how powerful technology it is.