The clinical use of 3D printing in surgery

Personalized Biomodel of the Cervical Spine for Laboratory Laminoplasty Training

OBJECTIVE

The use of biomodels in the laboratory for studying and training cervical laminoplasty has not yet been reported. We propose the use of a cervical spine biomodel for surgical laminoplasty training.

METHODS

This is an experimental study. Ten 3D identical cervical spine biomodels were printed based on computed tomography (CT) and magnetic resonance imaging scans of a patient diagnosed with spondylotic cervical myelopathy. The additive manufacturing method used fused deposition modeling and polylactic acid (PLA) was selected as the raw material. The sample was divided into 2 groups: control (n = 5; the biomodels were submitted to CT scanning) and open-door (n = 5; the biomodels were submitted to open-door laminoplasty and postoperative CT). The area and anteroposterior diameter of the vertebral canal were measured on CT scans.

RESULTS

Printing each piece took 12 hours. During the surgical procedure, there was sufficient support from the biomodels to keep them immobilized. Using the drill was feasible; however continuous irrigation was mandatory to prevent plastic material overheating. The raw material made the biomodel CT study possible. The vertebral canal dimensions increased 24.80% (0.62 cm2) in area and 24.88% (3.12 mm) in anteroposterior diameter CONCLUSIONS: The cervical spine biomodels can be used for laminoplasty training, even by using thermosensitive material such as PLA. The use of continuous irrigation is essential while drilling.

The development of direct 3-dimensional printing of patient-specific mitral valve in soft material for simulation and procedural planning

Objectives

Replicating 3-dimensional prints of patient-specific mitral valves in soft materials is a cumbersome and time-consuming process. The aim of this study was to develop a method for a direct 3-dimensional printing of patient-specific mitral valves in soft material for simulation-based training and procedural planning.

Methods

A process was developed based on data acquisition using 3-dimensional transesophageal echocardiography Cartesian Digital Imaging and Communication of Medicine format, image processing using software (Vesalius3D, Blender, Meshlab, Atum3D Operation Station), and 3-dimensional printing using digital light processing, an additive manufacturing process based on photopolymer resins. Experiments involved adjustment of 3 variables: curing times, model thinness, and lattice structuring during the printing process. Printed models were evaluated for suitability in physical simulation by an experienced mitral valve surgeon.

Results

Direct 3-dimensional printing of a patient's mitral valve in soft material was completed within a range of 1.5 to 4.5 hours. Prints with postcuring times of 5, 7, 10, and 15 minutes resulted in increased stiffness. The mitral valves with 2.0-mm and 2.4-mm thinner leaflets felt more flexible without tear of the sutures through the material. The addition of lattice structures made the prints more compliant and better supported suturing.

Conclusions

Direct 3-dimensional printing of a realistic and flexible patient-specific mitral valve was achieved within a few hours. A combination of thinner leaflets, reduced curing time, and lattice structures enabled the creation of a realistic patient-specific mitral valve in soft material for physical simulation.

4D printing of biological macromolecules employing handheld bioprinters for in situ wound healing applications

In situ bioprinting may be preferred over standard in vitro bioprinting in specific cases when de novo tissues are to be created directly on the appropriate anatomical region in the live organism, employing the body as a bioreactor. So far, few efforts have been made to create in situ tissues that can be safely halted and immobilized during printing in preclinical live animals. However, the technique has to be improved significantly in order to manufacture complex tissues in situ, which may be attainable in the future thanks to multidisciplinary advances in tissue engineering. Thanks to the biological macromolecules, natural and synthetic hydrogels and polymers are among the most used biomaterials in in situ bioprinting procedure. Bioprinters, which encounter multiple challenges, including cross-linking the printed structure, adjusting the rheology parameters, and printing various constructs. The introduction of handheld 3D and 4D bioprinters might potentially overcome the difficulties and problems associated with using traditional bioprinters. Studies showed that this technique could be efficient in wound healing and skin tissue regeneration. This study aims to analyze the benefits and difficulties associated with materials in situ 4D printing via handheld bioprinters.

Three-Dimensional Printing in Spinal Surgery

OBJECTIVES

Carry out an update and systematic review on the use of three-dimensional printing (3DP) in spinal surgery.

METHODS

A systematic literature review was performed using the PubMed database in March 2024. "Spine surgery" and "3DP" were the search terms. Only articles published from 2014 to 2024 and clinical trails were selected for inclusion. Non-English or Spanish articles were excluded. This review complied with the Preferred Reported Items for Systematic Reviews and Meta-Analysis guideline.

RESULTS

Ten articles were included after screening and evaluation. The majority of the studied diseases were deformities (n = 3) and traumas (n = 3), followed by degenerative diseases (n = 2). Two articles dealt with surgical techniques. Six articles studied the creation of personalized guides for inserting screws; 2 were about education, one related to educating patients about their disease and the other to teaching residents surgical techniques; 2 other articles addressed surgical planning, where biomodels were printed to study anatomy and surgical programming.

CONCLUSIONS

3DP is one of the most-used tools in spine surgeries, but there are still randomized articles available on the subject. Using this technology seems to have a positive effect on patient education regarding their disease and surgical planning.

Perspective or Spectacle? Teaching thoracic aortic anatomy in a mixed reality assisted educational approach- a two-armed randomized pilot study

PURPOSE

Anatomical understanding is an important basis for medical teaching, especially in a surgical context. The interpretation of complex vascular structures via two-dimensional visualization can yet be difficult, particularly for students. The objective of this study was to investigate the feasibility of an MxR-assisted educational approach in vascular surgery undergraduate education, comparing an MxR-based teaching-intervention with CT-based material for learning and understanding the vascular morphology of the thoracic aorta.

METHODS

In a prospective randomized controlled trial learning success and diagnostic skills following an MxR- vs. a CT-based intervention was investigated in 120 thoracic aortic visualizations. Secondary outcomes were motivation, system-usability as well as workload/satisfaction. Motivational factors and training-experience were also assessed. Twelve students (7 females; mean age: 23 years) were randomized into two groups undergoing educational intervention with MxR or CT.

RESULTS

Evaluation of learning success showed a mean improvement of 1.17 points (max.score: 10; 95%CI: 0.36-1.97). The MxR-group has improved by a mean of 1.33 [95% CI: 0.16-2.51], against 1.0 points [95% CI: -0.71- 2.71] in the CT-group. Regarding diagnostic skills, both groups performed equally (CT-group: 58.25 ± 7.86 vs. MxR-group:58.5 ± 6.60; max. score 92.0). 11/12 participants were convinced that MxR facilitated learning of vascular morphologies. The usability of the MxR-system was rated positively, and the perceived workload was low.

CONCLUSION

MxR-systems can be a valuable addition to vascular surgery education. Further evaluation of the technology in larger teaching situations are required. Especially regarding the acquisition of practical skills, the use of MxR-systems offers interesting application possibilities in surgical education.

A review of the ethical considerations for the use of 3D printed materials in medical and allied health education and a proposed collective path forward

3D scanning and printing technologies are quickly evolving and offer great potential for use in gross anatomical education. The use of human body donors to create digital scans and 3D printed models raises ethical concerns about donor informed consent, potential commodification, and access to and storage of potentially identifiable anatomical reproductions. This paper reviews available literature describing ethical implications for the application of these emerging technologies, existing published best practices for managing and sharing 2D imaging, and current adherence to these best practices by academic body donation programs. We conclude that informed consent is paramount for all uses of human donor and human donor-derived materials and that currently there is considerable diversity in adherence to established best practices for the management and sharing of 3D digital content derived from human donors. We propose a new and simplified framework for categorizing donor-derived teaching materials and the corresponding level of consent required for digital sharing. This framework proposes an equivalent minimum level of specific consent for human donor and human donor-derived materials relative to generalized, nonidentical teaching materials (i.e., artificial plastic models). Likewise, we propose that the collective path forward should involve the creation of a centralized, secure repository for digital human donor 3D content as a mechanism for accumulating, regulating, and controlling the distribution of properly consented human donor-derived 3D digital content that will also increase the availability of ethically created human-derived teaching materials while discouraging commodification.

Design and application of a novel 3D printing digital navigation template for cubitus varus deformity in children

Background

This study was aimed to assess the feasibility and efficacy of 3D printing digital template for treatment of cubitus varus deformity.

Methods

32 patients who underwent lateral closing osteotomy were evaluated between January 2018 and January 2020 in this retrospective study. Navigation templates were used in 17 cases, while conventional surgery in 15 cases. The carrying angles before and after surgery, operation time and elbow joint function were compared.

Results

Navigation templates matched well with the anatomical markers of the lateral humerus. More accurate osteotomy degrees, shorter operation time and less radiation exposure were achieved in the navigation template group (p < 0.05). At the last follow-up time, significant difference was found based on the Bellemore criteria (p = 0.0288).

Conclusions

The novel navigation template can shorten operation time, improve the lateral closing osteotomy accuracy and improve postoperative elbow joint function.

Reduction of surgical complications via 3D models during robotic assisted radical prostatectomy: review of current evidence and meta-analysis

The use of 3-dimensional (3D) technology has become increasingly popular across different surgical specialities to improve surgical outcomes. 3D technology has the potential to be applied to robotic assisted radical prostatectomy to visualise the patient's prostate anatomy to be used as a preoperative and peri operative surgical guide. This literature review aims to analyse all relevant pre-existing research on this topic. Following PRISMA guidelines, a search was carried out on PubMed, Medline, and Scopus. A total of seven studies were included in this literature review; two of which used printed-3D models and the remaining five using virtual augmented reality (AR) 3D models. Results displayed variation with select studies presenting that the use of 3D models enhances surgical outcomes and reduces complications whilst others displayed conflicting evidence. The use of 3D modelling within surgery has potential to improve various areas. This includes the potential surgical outcomes, including complication rates, due to improved planning and education.

A Cost-Effective, Three-Dimensionally Printed Simulation Model Facilitates Learning of Bilobed and Banner Flaps for Mohs Nasal Reconstruction: A Pilot Study

SUMMARY

Flap design for Mohs reconstruction is a complex 3-dimensional process. Simulation offers trainees the chance to practice techniques safely before performing them in the operating room. To aid in teaching, the authors developed a high-fidelity, cost-effective model of the face using three-dimensional printing to simulate flap reconstruction after Mohs surgery. A model face was sculpted digitally to include skin, bone, and cartilage. Negative molds were printed and used to cast silicone, representing external skin. The cartilage and bone models were combined to create a single three-dimensionally printed base. Surgical residents practiced performing banner and bilobed flaps on the simulation model, and improvement was assessed using boards-style pretests and posttests assessing flap design on clinical photographs. Medical students were randomized to complete a similar practice session with the model or a reading on the topic, after which they completed the same assessment. Participants also completed a questionnaire about the model's didactic and monetary value. Residents showed significant improvement after use of the model (banner flap: P = 0.002, bilobed flap: P = 0.04). Medical students who used the model scored significantly higher than those assigned to train by reading ( P = 0.001). Subjective comfort with flap design and execution increased after practice with the model ( P = 0.001). The cost of materials for each model was $2.50; participants reported willingness to pay $24.36 (mean) for this tool. This accessible model was superior to traditional teaching materials for Mohs reconstruction, and aided the comfort and proficiency of trainees.

Advancements and Applications of Three-dimensional Printing Technology in Surgery

Three-dimensional (3D) printing technology has revolutionized surgical practices, offering precise solutions for planning, education, and patient care. Surgeons now wield tangible, patient-specific 3D models derived from imaging data, allowing for meticulous presurgical planning. These models enhance surgical precision, reduce operative times, and minimize complications, ultimately improving patient outcomes. The technology also serves as a powerful educational tool, providing hands-on learning experiences for medical professionals and clearer communication with patients and their families. Despite its advantages, challenges such as model accuracy and material selection exist. Ongoing advancements, including bioactive materials and artificial intelligence integration, promise to further enhance 3D printing's impact. The future of 3D printing in surgery holds potential for regenerative medicine, increased global accessibility, and collaboration through telemedicine. Interdisciplinary collaboration between medical and engineering fields is crucial for responsible and innovative use of this technology.

The Past, Present, and Future of Tubular Melt Electrowritten Constructs to Mimic Small Diameter Blood Vessels - A Stable Process?

Melt Electrowriting (MEW) is a continuously growing manufacturing platform. Its advantage is the consistent production of micro- to nanometer fibers, that stack intricately, forming complex geometrical shapes. MEW allows tuning of the mechanical properties of constructs via the geometry of deposited fibers. Due to this, MEW can create complex mechanics only seen in multi-material compounds and serve as guiding structures for cellular alignment. The advantage of MEW is also shown in combination with other biotechnological manufacturing methods to create multilayered constructs that increase mechanical approximation to native tissues, biocompatibility, and cellular response. These features make MEW constructs a perfect candidate for small-diameter vascular graft structures. Recently, studies have presented fascinating results in this regard, but is this truly the direction that tubular MEW will follow or are there also other options on the horizon? This perspective will explore the origins and developments of tubular MEW and present its growing importance in the field of artificial small-diameter vascular grafts with mechanical modulation and improved biomimicry and the impact of it in convergence with other manufacturing methods and how future technologies like AI may influence its progress.

4D printing for biomedical applications

While three-dimensional (3D) printing excels at fabricating static constructs, it fails to emulate the dynamic behavior of native tissues or the temporal programmability desired for medical devices. Four-dimensional (4D) printing is an advanced additive manufacturing technology capable of fabricating constructs that can undergo pre-programmed changes in shape, property, or functionality when exposed to specific stimuli. In this Perspective, we summarize the advances in materials chemistry, 3D printing strategies, and post-printing methodologies that collectively facilitate the realization of temporal dynamics within 4D-printed soft materials (hydrogels, shape-memory polymers, liquid crystalline elastomers), ceramics, and metals. We also discuss and present insights about the diverse biomedical applications of 4D printing, including tissue engineering and regenerative medicine, drug delivery, in vitro models, and medical devices. Finally, we discuss the current challenges and emphasize the importance of an application-driven design approach to enable the clinical translation and widespread adoption of 4D printing.

Just the gastrointestinal stromal tumor: A case report of medical modeling of a rectal gastrointestinal stromal tumor

A 54-year-old African-American male presented to the colorectal surgery clinic with the chief complaint of a painful anal swelling that had been ongoing for several weeks. An adequate rectal examination was not possible due to severe pain. Therefore, he was taken to the operating room for an exam under anesthesia where a presacral mass was identified. A transgluteal core needle biopsy was performed which was consistent with gastrointestinal stromal tumor. Computed tomography imaging identified a 16 cm ×10 cm ×9 cmrectal gastrointestinal stromal tumor. Given the size and location, the patient began treatment with neoadjuvant Imatinib. His progress was followed with serial computed tomography scans and clinic visits. A 3D model was created the tumor and surrounding structures to aide in pre- and intraoperative planning. The model was utilized during patient education and found to valuable in describing the potential for levator invasion and framing potential post-operative outcomes. The patient was able to undergo rectal preservation via a robotic low anterior resection with a transanal total mesorectal excision, coloanal anastomosis, and diverting ileostomy.

Does using 3D printed models for pre-operative planning improve surgical outcomes of foot and ankle fracture fixation? A systematic review and meta-analysis

PURPOSE

The systematic review aims to establish the value of using 3D printing-assisted pre-operative planning, compared to conventional planning, for the operative management of foot and ankle fractures.

METHODS

The systematic review was performed according to PRISMA guidelines. Two authors performed searches on three electronic databases. Studies were included if they conformed to pre-established eligibility criteria. Primary outcome measures included intraoperative blood loss, operation duration, and fluoroscopy time. The American orthopaedic foot and ankle score (AOFAS) was used as a secondary outcome. Quality assessment was completed using the Cochrane RoB2 form and a meta-analysis was performed to assess heterogeneity.

RESULTS

Five studies met the inclusion and exclusion criteria and were eventually included in the review. A meta-analysis established that using 3D printed models for pre-operative planning resulted in a significant reduction in operation duration (mean difference [MD] = - 23.52 min, 95% CI [- 39.31, - 7.74], p = 0.003), intraoperative blood loss (MD = - 30.59 mL, 95% CI [- 46.31, - 14.87], p = 0.0001), and number of times fluoroscopy was used (MD = - 3.20 times, 95% CI [- 4.69, - 1.72], p < 0.0001). Using 3D printed models also significantly increased AOFAS score results (MD = 2.24, 95% CI [0.69, 3.78], p = 0.005), demonstrating improved ankle health.

CONCLUSION

The systematic review provides promising evidence that 3D printing-assisted surgery significantly improves treatment for foot and ankle fractures in terms of operation duration, intraoperative blood loss, number of times fluoroscopy was used intraoperatively, and improved overall ankle health as measured by the AOFAS score.

First experiences of a hospital-based 3D printing facility - an analytical observational study

PURPOSE

To identify the clinical impact and potential benefits of in-house 3D-printed objects through a questionnaire, focusing on three principal areas: patient education; interdisciplinary cooperation; preoperative planning and perioperative execution.

MATERIALS AND METHODS

Questionnaires were sent from January 2021 to August 2022. Participants were directed to rate on a scale from 1 to 10.

RESULTS

The response rate was 43%. The results of the rated questions are averages. 84% reported using 3D-printed objects in informing the patient about their condition/procedure. Clinician-reported improvement in patient understanding of their procedure/disease was 8.1. The importance of in-house placement was rated 9.2. 96% reported using the 3D model to confer with colleagues. Delay in treatment due to 3D printing lead-time was 1.8. The degree with which preoperative planning was altered was 6.9. The improvement in clinician perceived preoperative confidence was 8.3. The degree with which the scope of the procedure was affected, in regard to invasiveness, was 5.6, wherein a score of 5 is taken to mean unchanged. Reduction in surgical duration was rated 5.7.

CONCLUSION

Clinicians report the utilization of 3D printing in surgical specialties improves procedures pre- and intraoperatively, has a potential for increasing patient engagement and insight, and in-house location of a 3D printing center results in improved interdisciplinary cooperation and allows broader access with only minimal delay in treatment due to lead-time.

The utility of three-dimensional modeling and printing in pediatric surgical patient and family education: a systematic review

BACKGROUND

Three-dimensional (3D) modeling and printing are increasingly being used in surgical settings. This technology has several applications including pre-operative surgical planning, inter-team communication, and patient education and counseling. The majority of research on 3D technology has focused on adult populations, where it has been found to be a useful tool for educating patients across various surgical specialties. There is a dearth, however, of research on the utility of 3D modeling and printing for patient and family education in pediatric populations. Our objective was to systematically review the current literature on how this modality is being utilized in pediatric surgical settings for patient and family education and counselling.

METHODS

We conducted a systematic review in accordance with PRISMA and CASP guidelines. The MEDLINE, CINAHL, Embase, and Web of Science databases were searched from inception to October 21, 2023, with no restrictions on language or geographical location. Citation chaining was used to ensure relevant papers were included. Articles were doubly screened and data was extracted independently by two authors. In the case of disagreement, a third author was consulted. Any articles pertaining to 3D modeling and printing in pediatric surgical settings for patient and family education and counseling were included.

RESULTS

Six articles met inclusion criteria and were used for qualitative analysis. Two involved questionnaires given to parents of children to assess their understanding of relevant anatomy, surgical procedure, and risks after viewing conventional CT images and again after viewing a 3D-printed model. One involved a quasi-experimental study to assess young patients' pre-operative surgical understanding and anxiety after undergoing conventional teaching as compared to after viewing a 3D storybook. One involved questionnaires given to parents of children in control and study groups to assess the usefulness of 3D printed models compared to conventional CT images in their understanding of relevant anatomy and the surgical procedure. Another study looked at the usefulness of 3D printed models compared to 2D and 3D CT images in providing caregiver understanding during the pre-operative consent process. The last article involved studying the impact of using 3D printing to help patients understand their disease and participate in decision-making processes during surgical consultations. In all six studies, utilizing 3D technology improved transfer of information between surgical team members and their patients and families.

CONCLUSION

Our systematic review suggests that 3D modeling and printing is a useful tool for patient and family education and counselling in pediatric surgical populations. Given the very small number of published studies, further research is needed to better define the utility of this technology in pediatric settings.

The Educational Impact of Radiology in Anatomy Teaching: A Field Study Using Cross-Sectional Imaging and 3D Printing for the Study of the Spine

INTRODUCTION

Cross-sectional imaging and 3D printing represent state-of-the-art approaches to improve anatomy teaching compared to traditional learning, but their use in medical schools remains limited. This study explores the utility of these educational tools for teaching normal and pathological spinal anatomy, aiming to improve undergraduate medical education.

MATERIALS AND METHODS

A field study was conducted on a cohort of undergraduate medical students who were exposed to anatomy lessons of the spine considering three learning paradigms: traditional learning, cross-sectional imaging examinations, and 3D printed models. 20 students (intervention group) received the three approaches, and other 20 students (control group) received the conventional (traditional) approach. The students were examined through a multiple-choice test and their results were compared to those of a control group exposed to traditional learning matched by age, sex and anatomy grades. In addition, students in the experimental group were assessed for their satisfaction with each learning method by means of an ad hoc questionnaire.

RESULTS

Students exposed to cross-sectional imaging and 3D printing demonstrated better knowledge outcomes compared to the control group. They showed high satisfaction rates and reported that these technologies enhanced spatial understanding and facilitated visualization of specific pathologies. However, limitations such as the representativeness of non-bone conditions in 3D printed models and the need for further knowledge on imaging fundamentals were highlighted.

CONCLUSION

Cross-sectional imaging and 3D printing offer valuable tools for enhancing the teaching of spinal anatomy in undergraduate medical education. Radiologists are well positioned to lead the integration of these technologies, and further research should explore their potential in teaching anatomy across different anatomical regions.

A survey regarding the organizational aspects and quality systems of in-house 3D printing in oral and maxillofacial surgery in Germany

PURPOSE

The aim of the study was to get a cross-sectional overview of the current status of specific organizational procedures, quality control systems, and standard operating procedures for the use of three-dimensional (3D) printing to assist in-house workflow using additive manufacturing in oral and maxillofacial surgery (OMFS) in Germany.

METHODS

An online questionnaire including dynamic components containing 16-29 questions regarding specific organizational aspects, process workflows, quality controls, documentation, and the respective backgrounds in 3D printing was sent to OMF surgeons in university and non-university hospitals as well as private practices with and without inpatient treatment facilities. Participants were recruited from a former study population regarding 3D printing; all participants owned a 3D printer and were registered with the German Association of Oral and Maxillofacial Surgery.

RESULTS

Sixty-seven participants answered the questionnaires. Of those, 20 participants ran a 3D printer in-unit. Quality assurance measures were performed by 13 participants and underlying processes by 8 participants, respectively. Standard operating procedures regarding computer-aided design and manufacturing, post-processing, use, or storage of printed goods were non-existent in most printing units. Data segmentation as well as computer-aided design and manufacturing were conducted by a medical doctor in most cases (n = 19, n = 18, n = 8, respectively). Most participants (n = 8) stated that "medical device regulations did not have any influence yet, but an adaptation of the processes is planned for the future."

CONCLUSION

The findings demonstrated significant differences in 3D printing management in OMFS, especially concerning process workflows, quality control, and documentation. Considering the ever-increasing regulations for medical devices, there might be a necessity for standardized 3D printing recommendations and regulations in OMFS.

Use of individualized 3D-printed models of pancreatic cancer to improve surgeons' anatomic understanding and surgical planning

OBJECTIVES

Three-dimensional (3D) printing has been increasingly used to create accurate patient-specific 3D-printed models from medical imaging data. We aimed to evaluate the utility of 3D-printed models in the localization and understanding of pancreatic cancer for surgeons before pancreatic surgery.

METHODS

Between March and September 2021, we prospectively enrolled 10 patients with suspected pancreatic cancer who were scheduled for surgery. We created an individualized 3D-printed model from preoperative CT images. Six surgeons (three staff and three residents) evaluated the CT images before and after the presentation of the 3D-printed model using a 7-item questionnaire (understanding of anatomy and pancreatic cancer [Q1-4], preoperative planning [Q5], and education for trainees or patients [Q6-7]) on a 5-point scale. Survey scores on Q1-5 before and after the presentation of the 3D-printed model were compared. Q6-7 assessed the 3D-printed model's effects on education compared to CT. Subgroup analysis was performed between staff and residents.

RESULTS

After the 3D-printed model presentation, survey scores improved in all five questions (before 3.90 vs. after 4.56, p < 0.001), with a mean improvement of 0.57‒0.93. Staff and resident scores improved after a 3D-printed model presentation (p < 0.05), except for Q4 in the resident group. The mean difference was higher among the staff than among the residents (staff: 0.50‒0.97 vs. residents: 0.27‒0.90). The scores of the 3D-printed model for education were high (trainees: 4.47 vs. patients: 4.60) compared to CT.

CONCLUSION

The 3D-printed model of pancreatic cancer improved surgeons' understanding of individual patients' pancreatic cancer and surgical planning.

CLINICAL RELEVANCE STATEMENT

The 3D-printed model of pancreatic cancer can be created using a preoperative CT image, which not only assists surgeons in surgical planning but also serves as a valuable educational resource for patients and students.

KEY POINTS

• A personalized 3D-printed pancreatic cancer model provides more intuitive information than CT, allowing surgeons to better visualize the tumor's location and relationship to neighboring organs. • In particular, the survey score was higher among staff who performed the surgery than among residents. • Individual patient pancreatic cancer models have the potential to be used for personalized patient education as well as resident education.

Effects of the individual three-dimensional printed craniofacial bones with a quick response code on the skull spatial knowledge of undergraduate medical students

Understanding the three-dimensional (3D) structure of the human skull is imperative for medical courses. However, medical students are overwhelmed by the spatial complexity of the skull. Separated polyvinyl chloride (PVC) bone models have advantages as learning tools, but they are fragile and expensive. This study aimed to reconstruct 3D-printed skull bone models (3D-PSBs) using polylactic acid (PLA) with anatomical characteristics for spatial recognition of the skull. Student responses to 3D-PSB application were investigated through a questionnaire and tests to understand the requirement of these models as a learning tool. The students were randomly divided into 3D-PSB (n = 63) and skull (n = 67) groups to analyze pre- and post-test scores. Their knowledge was improved, with the gain scores of the 3D-PSB group (50.0 ± 3.0) higher than that of the skull group (37.3 ± 5.2). Most students agreed that using 3D-PSBs with quick response codes could improve immediate feedback on teaching (88%; 4.41 ± 0.75), while 85.9% of the students agreed that individual 3D-PSBs clarified the structures hidden within the skull (4.41 ± 0.75). The ball drop test revealed that the mechanical strength of the cement/PLA model was significantly greater than that of the cement or PLA model. The prices of the PVC, cement, and cement/PLA models were 234, 1.9, and 10 times higher than that of the 3D-PSB model, respectively. These findings imply that low-cost 3D-PSB models could revolutionize skull anatomical education by incorporating digital technologies like the QR system into the anatomical teaching repertoire.

The Innovation Press: A Primer on the Anatomy of Digital Design in Plastic Surgery

ABSTRACT

Three-dimensional (3D) printing continues to revolutionize the field of plastic surgery, allowing surgeons to adapt to the needs of individual patients and innovate, plan, or refine operative techniques. The utility of this manufacturing modality spans from surgical planning, medical education, and effective patient communication to tissue engineering and device prototyping and has valuable implications in every facet of plastic surgery. Three-dimensional printing is more accessible than ever to the surgical community, regardless of previous background in engineering or biotechnology. As such, the onus falls on the surgeon-innovator to have a functional understanding of the fundamental pipeline and processes in actualizing such innovation. We review the broad range of reported uses for 3D printing in plastic surgery, the process from conceptualization to production, and the considerations a physician must make when using 3D printing for clinical applications. We additionally discuss the role of computer-assisted design and manufacturing and virtual and augmented reality, as well as the ability to digitally modify devices using this software. Finally, a discussion of 3D printing logistics, printer types, and materials is included. With innovation and problem solving comprising key tenets of plastic surgery, 3D printing can be a vital tool in the surgeon's intellectual and digital arsenal to span the gap between concept and reality.

3-D Printed Fracture Models Improve Resident Performance and Clinical Outcomes in Operative Fracture Management

OBJECTIVE

To determine if preoperative examination of patient additive manufactured (AM) fracture models can be used to improve resident operative competency and patient outcomes.

DESIGN

Prospective cohort study. Seventeen matched pairs of fracture fixation surgeries (for a total of 34 surgeries) were performed. Residents first performed a set of baseline surgeries (n = 17) without AM fracture models. The residents then performed a second set of surgeries randomly assigned to include an AM model (n = 11) or to omit it (n = 6). Following each surgery, the attending surgeon evaluated the resident using an Ottawa Surgical Competency Operating Room Evaluation (O-Score). The authors also recorded clinical outcomes including operative time, blood loss, fluoroscopy duration, and patient reported outcome measurement information system (PROMIS) scores of pain and function at 6 months.

SETTING

Single-center academic level one trauma center.

PARTICIPANTS

Twelve orthopaedic residents, between postgraduate year (PGY) 2 and 5, participated in this study.

RESULTS

Residents significantly improved their O-Scores between the first and second surgery when they trained with AM models for the second surgery (p = 0.004, 2.43 ± 0.79 versus 3.73 ± 0.64). Similar improvements were not observed in the control group (p = 0.916, 2.69 ± 0.69 versus 2.77 ± 0.36). AM model training also significantly improved clinical outcomes, including surgery time (p = 0.006), fluoroscopy exposure time (p = 0.002), and patient reported functional outcomes (p = 0.0006).

CONCLUSIONS

Conclusions: Training with AM fracture models improves the performance of orthopaedic surgery residents during fracture surgery.

Analysis of the approach angle to medial orbitotomy that avoids accidental neurotrauma in the mesaticephalic dog skull utilizing 3D computer models and virtual surgical planning

This study was conducted to determine an approach angle to medial orbitotomy that avoids accidental neurotrauma in mesaticephalic dogs. Medical records of dogs with mesaticephalic skulls that were presented to the veterinary medical teaching hospital for head computed tomography (CT) between September 2021 and February 2022 were reviewed. Descriptive data were queried, and CT findings were analyzed. Dogs greater than 20 kg and possessing a disease-free orbitozygomaticomaxillary complex (OZMC) on at least one side of the skull were included in this study. Digital imaging and communications in medicine (DICOM) files of head CT studies were imported into medical modeling software, and the safe approach angle for medial orbitotomy was determined using three-dimensional (3D) computer models and virtual surgical planning (VSP) principles. Angles were measured along the ventral orbital crest (VOC) from the rostral cranial fossa (RCF) to the rostral alar foramen (RAF). The safe approach angle at four points from rostral to caudal along the VOC was measured. The results at each location were reported as mean, median, 95% CI, interquartile ranges, and distribution. The results were statistically different at each location and generally increased from rostral to caudal. The variances between subjects and the differences between locations were large enough to suggest a standard safe approach angle in mesaticephalic dogs cannot be determined and should be measured for each patient. A standardized approach angle to medial orbitotomy is not possible in the mesaticephalic dog. Computer modeling and VSP principles should be implemented as part of the surgical planning process to accurately measure the safe approach angle along the VOC.

Low-density 3D-printed boluses with honeycomb infill 3D-printed boluses in radiotherapy

PURPOSE

Dosimetric characteristics of 3D-printed plates using different infill percentage and materials was the purpose of our study.

METHODS

Test plates with 5%, 10%, 15% and 20% honeycomb structure infill were fabricated using TPU and PLA polymers. The Hounsfield unit distribution was determined using a Python script. Percentage Depth Dose (PDD) distribution in the build-up region was measured with the Markus plane-parallel ionization chamber for an open 10x10 cm² field of 6 MV. PDD was measured at a depth of 1 mm, 5 mm, 10 mm and 15 mm. Measurements were compared with Eclipse treatment planning system calculations using AAA and Acuros XB algorithms.

RESULTS

The mean HU for CT scans of 3D-printed TPU plates increased with percentage infill increase from -739 HU for 5% to -399 HU for 20%. Differences between the average HU for TPU and PLA did not exceed 2% for all percentage infills. Even using a plate with the lowest infill PDD at 1 mm depth increase from 44.7% (without a plate) to 76.9% for TPU and 76.6% for PLA. Infill percentage did not affect the dose at depths greater than 5 mm. Differences between measurements and TPS calculations were less than 4.1% for both materials, regardless of the infill percentage and depth.

CONCLUSIONS

The use of 3D-printed light boluses increases the dose in the build-up region, which was shown based on the dosimetric measurements and TPS calculations.

An interactive and realistic phantom for cricothyroidotomy simulation of a patient with obesity through a reusable design using 3D-printing and Arduino

BACKGROUND AND OBJECTIVES

Proper airway management during emergencies can prevent serious complications. However, cricothyroidotomy is challenging in patients with obesity. Since this technique is not performed frequently but at a critical time, the opportunity for trainees is rare. Simulators for these procedures are also lacking. Therefore, we proposed a realistic and interactive cricothyroidotomy simulator.

METHODS

All anatomical structures were modeled based on computed tomography images of a patient with obesity. To mimic the feeling of incision during cricothyroidotomy, the incision site was modeled to distinguish between the skin and fat. To reinforce the educational purpose, capacitive touch sensors were attached to the artery, vein, and thyroid to generate audio feedback. The tensile strength of the silicone-cast skin was measured to verify the similarity of the mechanical properties between humans and our model. The fabrication and assembly accuracies of the phantom between the Standard Tessellation Language and the fabricated model were evaluated. Audio feedback through sensing the anatomy parts and utilization was evaluated.

RESULTS

The body, skull, clavicle, artery, vein, and thyroid were fabricated using fused deposition modeling (FDM) with polylactic acid. A skin mold was fabricated using FDM with thermoplastic polyurethane. A fat mold was fabricated using stereolithography apparatus (SLA) with a clear resin. The airway and tongue were fabricated using SLA with an elastic resin. The tensile strength of the skin using silicone with and without polyester mesh was 2.63 ± 0.68 and 2.46 ± 0.21 MPa. The measurement errors for fabricating and assembling parts of the phantom between the STL and the fabricated models were -0.08 ± 0.19 mm and 0.13 ± 0.64 mm. The measurement errors internal anatomy embodied surfaces in fat part were 0.41 ± 0.89 mm. Audio feedback was generated 100% in all the areas tested. The realism, understanding of clinical skills, and intention to retrain were 7.1, 8.8, and 8.3 average points.

CONCLUSIONS

Our simulator can provide a realistic simulation experience for trainees through a realistic feeling of incision and audio feedback, which can be used for actual clinical education.

Application of 3D Printing in Bone Grafts

The application of 3D printing in bone grafts is gaining in importance and is becoming more and more popular. The choice of the method has a direct impact on the preparation of the patient for surgery, the probability of rejection of the transplant, and many other complications. The aim of the article is to discuss methods of bone grafting and to compare these methods. This review of literature is based on a selective literature search of the PubMed and Web of Science databases from 2001 to 2022 using the search terms “bone graft”, “bone transplant”, and “3D printing”. In addition, we also reviewed non-medical literature related to materials used for 3D printing. There are several methods of bone grafting, such as a demineralized bone matrix, cancellous allograft, nonvascular cortical allograft, osteoarticular allograft, osteochondral allograft, vascularized allograft, and an autogenic transplant using a bone substitute. Currently, autogenous grafting, which involves removing the patient’s bone from an area of low aesthetic importance, is referred to as the gold standard. 3D printing enables using a variety of materials. 3D technology is being applied to bone tissue engineering much more often. It allows for the treatment of bone defects thanks to the creation of a porous scaffold with adequate mechanical strength and favorable macro- and microstructures. Bone tissue engineering is an innovative approach that can be used to repair multiple bone defects in the process of transplantation. In this process, biomaterials are a very important factor in supporting regenerative cells and the regeneration of tissue. We have years of research ahead of us; however, it is certain that 3D printing is the future of transplant medicine.

Quality assurance in 3D-printing: A dimensional accuracy study of patient-specific 3D-printed vascular anatomical models

3D printing enables the rapid manufacture of patient-specific anatomical models that substantially improve patient consultation and offer unprecedented opportunities for surgical planning and training. However, the multistep preparation process may inadvertently lead to inaccurate anatomical representations which may impact clinical decision making detrimentally. Here, we investigated the dimensional accuracy of patient-specific vascular anatomical models manufactured via digital anatomical segmentation and Fused-Deposition Modelling (FDM), Stereolithography (SLA), Selective Laser Sintering (SLS), and PolyJet 3D printing, respectively. All printing modalities reliably produced hand-held patient-specific models of high quality. Quantitative assessment revealed an overall dimensional error of 0.20 ± 3.23%, 0.53 ± 3.16%, -0.11 ± 2.81% and -0.72 ± 2.72% for FDM, SLA, PolyJet and SLS printed models, respectively, compared to unmodified Computed Tomography Angiograms (CTAs) data. Comparison of digital 3D models to CTA data revealed an average relative dimensional error of -0.83 ± 2.13% resulting from digital anatomical segmentation and processing. Therefore, dimensional error resulting from the print modality alone were 0.76 ± 2.88%, + 0.90 ± 2.26%, + 1.62 ± 2.20% and +0.88 ± 1.97%, for FDM, SLA, PolyJet and SLS printed models, respectively. Impact on absolute measurements of feature size were minimal and assessment of relative error showed a propensity for models to be marginally underestimated. This study revealed a high level of dimensional accuracy of 3D-printed patient-specific vascular anatomical models, suggesting they meet the requirements to be used as medical devices for clinical applications.

Virtual surgical planning and 3D printing in pediatric musculoskeletal oncological resections: a proof-of-concept description

BACKGROUND AND OBJECTIVES

Patient-specific models may have a role in planning and executing complex surgical procedures. However, creating patient-specific models with virtual surgical planning (VSP) has many steps, from initial imaging to finally realizing the three-dimensional printed model (3DPM). This manuscript evaluated the feasibility and potential benefits of multimodal imaging and geometric VSP and 3DPM in pediatric orthopedic tumor resection and reconstruction.

MATERIALS AND METHODS

Twelve children with Ewing's sarcoma, osteosarcoma, or chondrosarcoma were studied. Computed tomography (CT) and contrast-enhanced magnetic resonance imaging (MRI) were acquired as the standard-of-care. Bony and soft tissue components of the tumor and the adjacent bone were segmented to create a computer-generated 3D model of the region. VSP used the computer-generated 3D model. The Objet350 Stratasys™ polyjet printer printed the final physical model used for pre-surgical planning, intraoperative reference, and patient education. Clinical impact, the utility of the model, and its geometric accuracy were assessed.

RESULTS

Subjectively, using the patient-specific model assisted in preoperative planning and intra-operative execution of the surgical plan. The mean difference between the models and the surgical resection was -0.09 mm (range: -0.29-0.45 mm). Pearson's correlation coefficient (r) of the cross-sectional area was -0.9994, linear regression r² = 0.9989, and the Bland Altman plot at 95% confidence interval showed all data within boundaries.

CONCLUSION

We studied the geometric accuracy, utility and clinical impact of VSP and 3DPM produced from multi-modal imaging studies and concluded 3DPM accurately represented the patients' tumor and proved very useful to the surgeon in both the preoperative surgical planning, patient and family education and operative phases. Future studies will be planned to evaluate surgery procedure duration and other outcomes.

Digital health: trends, opportunities and challenges in medical devices, pharma and bio-technology

Digital health interventions refer to the use of digital technology and connected devices to improve health outcomes and healthcare delivery. This includes telemedicine, electronic health records, wearable devices, mobile health applications, and other forms of digital health technology. To this end, several research and developmental activities in various fields are gaining momentum. For instance, in the medical devices sector, several smart biomedical materials and medical devices that are digitally enabled are rapidly being developed and introduced into clinical settings. In the pharma and allied sectors, digital health-focused technologies are widely being used through various stages of drug development, viz. computer-aided drug design, computational modeling for predictive toxicology, and big data analytics for clinical trial management. In the biotechnology and bioengineering fields, investigations are rapidly growing focus on digital health, such as omics biology, synthetic biology, systems biology, big data and personalized medicine. Though digital health-focused innovations are expanding the horizons of health in diverse ways, here the development in the fields of medical devices, pharmaceutical technologies and biotech sectors, with emphasis on trends, opportunities and challenges are reviewed. A perspective on the use of digital health in the Indian context is also included.

Properties and Implementation of 3-Dimensionally Printed Models in Spine Surgery: A Mixed-Methods Review With Meta-Analysis

OBJECTIVE

Spine surgery addresses a wide range of spinal pathologies. Potential applications of 3-dimensional (3D) printed in spine surgery are broad, encompassing education, planning, and simulation. The objective of this study was to explore how 3D-printed spine models are implemented in spine surgery and their clinical applications.

METHODS

Methods were combined to create a scoping review with meta-analyses. PubMed, EMBASE, the Cochrane Library, and Scopus databases were searched from 2011 to 7 September 2021. Results were screened independently by 2 reviewers. Studies utilizing 3D-printed spine models in spine surgery were included. Articles describing drill guides, implants, or nonoriginal research were excluded. Data were extracted according to reporting guidelines in relation to study information, use of model, 3D printer and printing material, design features of the model, and clinical use/patient-related outcomes. Meta-analyses were performed using random-effects models.

RESULTS

Forty articles were included in the review, 3 of which were included in the meta-analysis. Primary use of the spine models included preoperative planning, education, and simulation. Six printing technologies were utilized. A range of substrates were used to recreate the spine and regional pathology. Models used for preoperative and intraoperative planning showed reductions in key surgical performance indicators. Generally, feedback for the tactility, utility, and education use of models was favorable.

CONCLUSIONS

Replicating realistic spine models for operative planning, education, and training is invaluable in a subspeciality where mistakes can have devastating repercussions. Future study should evaluate the cost-effectiveness and the impact spine models have of spine surgery outcomes.

3D printing in the planning and teaching of endovascular procedures

BACKGROUND

The introduction of 3D printing in the medical field led to new possibilities in the planning of complex procedures, as well as new ways of training junior physicians. Especially in the field of vascular interventions, 3D printing has a wide range of applications.

METHODOLOGICAL INNOVATIONS

3D-printed models of aortic aneurysms can be used for procedural training of endovascular aortic repair (EVAR), which can help boost the physician's confidence in the procedure, leading to a better outcome for the patient. Furthermore, it allows for a better understanding of complex anatomies and pathologies. In addition to teaching applications, the field of pre-interventional planning benefits greatly from the addition of 3D printing. Especially in the preparation for a complex endovascular aortic repair, prior orientation and test implantation of the stent grafts can further improve outcomes and reduce complications. For both teaching and planning applications, high-quality imaging datasets are required that can be transferred into a digital 3D model and subsequently printed in 3D. Thick slice thickness or suboptimal contrast agent phase can reduce the overall detail of the digital model, possibly concealing crucial anatomical details.

CONCLUSION

Based on the digital 3D model created for 3D printing, another new visualization technique might see future applications in the field of vascular interventions: virtual reality (VR). It enables the physician to quickly visualize a digital 3D model of the patient's anatomy in order to assess possible complications during endovascular repair. Due to the short transfer time from the radiological dataset into the VR, this technique might see use in emergency situations, where there is no time to wait for a printed model.

Three-dimensional Printer Molds for Vaginal Agenesis: An Individualized Approach as Conservative Treatment

OBJECTIVE

 The aim of this study was to evaluate the use of vaginal molds, made with three-dimensional (3D) printing, for conservative treatment through vaginal dilation in patients with vaginal agenesis (VA).

METHODS

 A total of 16 patients with a diagnosis of VA (Mayer-Rokitansky-Küster-Hauser syndrome, total androgen insensitivity syndrome, and cervicovaginal agenesis) from the Federal University of São Paulo were selected. Device production was performed in a 3D printer, and the polymeric filament of the lactic polyacid (PLA) was used as raw material. A personalized treatment was proposed and developed for each patient.

RESULTS

 There were 14 patients who reached a final vaginal length of 6 cm or more. The initial total vaginal length (TVL) mean (SD) was 1.81(1.05) and the final TVL mean (SD) was 6.37 (0.94); the difference, analyzed as 95% confidence interval (95% CI) was 4.56 (5.27-3.84) and the effect size (95% CI) was 4.58 (2.88-6.28).

CONCLUSION

 The 3D printing molds for vaginal dilation were successful in 87.5% of the patients. They did not present any major adverse effects and offered an economical, accessible, and reproducible strategy for the treatment of VA.

Organs in Color: Utilizing Free Software and Emerging Multi Jet Fusion Technology to Color and Surface Label 3D-Printed Anatomical Models

3D printing (3DP) is a rapidly evolving innovative technology that has already been utilized for the development of educational anatomic models. Until recently, it was difficult and tedious to create multi-colored models and especially labels due to technological constraints. In this technical note, a comprehensive guide for creating labeled and color-coded anatomic models was created using free software, Blender. We have composed a step-by-step process for taking an existing 3D model and adding labeling and color that is compatible with modern high-quality 3D printing technologies (Multi Jet Fusion). We provided colored and labeled 3D renderings of the surface anatomy of the brain, ventricular system of the brain, the segments of the liver, and coronary arteries as examples of the diverse potential of this technology. Additionally, we 3D printed actual models of the surface anatomy of the brain and ventricles of the brain using HP Multi Jet Fusion to demonstrate the potential of this technology in the creation of anatomic models.

Three-dimensional printing and 3D slicer powerful tools in understanding and treating neurosurgical diseases

With the development of the 3D printing industry, clinicians can research 3D printing in preoperative planning, individualized implantable materials manufacturing, and biomedical tissue modeling. Although the increased applications of 3D printing in many surgical disciplines, numerous doctors do not have the specialized range of abilities to utilize this exciting and valuable innovation. Additionally, as the applications of 3D printing technology have increased within the medical field, so have the number of printable materials and 3D printers. Therefore, clinicians need to stay up-to-date on this emerging technology for benefit. However, 3D printing technology relies heavily on 3D design. 3D Slicer can transform medical images into digital models to prepare for 3D printing. Due to most doctors lacking the technical skills to use 3D design and modeling software, we introduced the 3D Slicer to solve this problem. Our goal is to review the history of 3D printing and medical applications in this review. In addition, we summarized 3D Slicer technologies in neurosurgery. We hope this article will enable many clinicians to leverage the power of 3D printing and 3D Slicer.

Implementation of an In-House 3D Manufacturing Unit in a Public Hospital’s Radiology Department

Objective: Three-dimensional printing has become a leading manufacturing technique in healthcare in recent years. Doubts in published studies regarding the methodological rigor and cost-effectiveness and stricter regulations have stopped the transfer of this technology in many healthcare organizations. The aim of this study was the evaluation and implementation of a 3D printing technology service in a radiology department. Methods: This work describes a methodology to implement a 3D printing service in a radiology department of a Spanish public hospital, considering leadership, training, workflow, clinical integration, quality processes and usability. Results: The results correspond to a 6-year period, during which we performed up to 352 cases, requested by 85 different clinicians. The training, quality control and processes required for the scaled implementation of an in-house 3D printing service are also reported. Conclusions: Despite the maturity of the technology and its impact on the clinic, it is necessary to establish new workflows to correctly implement them into the strategy of the health organization, adjusting it to the needs of clinicians and to their specific resources. Significance: This work allows hospitals to bridge the gap between research and 3D printing, setting up its transfer to clinical practice and using implementation methodology for decision support.

Guide for starting or optimizing a 3D printing clinical service

Three-dimensional (3D) printing has applications in many fields and has gained substantial traction in medicine as a modality to transform two-dimensional scans into three-dimensional renderings. Patient-specific 3D printed models have direct patient care uses in surgical and procedural specialties, allowing for increased precision and accuracy in developing treatment plans and guiding surgeries. Medical applications include surgical planning, surgical guides, patient and trainee education, and implant fabrication. 3D printing workflow for a laboratory or clinical service that produces anatomic models and guides includes optimizing imaging acquisition and post-processing, segmenting the imaging, and printing the model. Quality assurance considerations include supervising medical imaging expert radiologists' guidance and self-implementing in-house quality control programs. The purpose of this review is to provide a workflow and guide for starting or optimizing laboratories and clinical services that 3D-print anatomic models or guides for clinical use.

Three-dimensional modeling in complex liver surgery and liver transplantation

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

Artificial Intelligence-Empowered 3D and 4D Printing Technologies toward Smarter Biomedical Materials and Approaches

In the last decades, 3D printing has played a crucial role as an innovative technology for tissue and organ fabrication, patient-specific orthoses, drug delivery, and surgical planning. However, biomedical materials used for 3D printing are usually static and unable to dynamically respond or transform within the internal environment of the body. These materials are fabricated ex situ, which involves first printing on a planar substrate and then deploying it to the target surface, thus resulting in a possible mismatch between the printed part and the target surfaces. The emergence of 4D printing addresses some of these drawbacks, opening an attractive path for the biomedical sector. By preprogramming smart materials, 4D printing is able to manufacture structures that dynamically respond to external stimuli. Despite these potentials, 4D printed dynamic materials are still in their infancy of development. The rise of artificial intelligence (AI) could push these technologies forward enlarging their applicability, boosting the design space of smart materials by selecting promising ones with desired architectures, properties, and functions, reducing the time to manufacturing, and allowing the in situ printing directly on target surfaces achieving high-fidelity of human body micro-structures. In this review, an overview of 4D printing as a fascinating tool for designing advanced smart materials is provided. Then will be discussed the recent progress in AI-empowered 3D and 4D printing with open-loop and closed-loop methods, in particular regarding shape-morphing 4D-responsive materials, printing on moving targets, and surgical robots for in situ printing. Lastly, an outlook on 5D printing is given as an advanced future technique, in which AI will assume the role of the fifth dimension to empower the effectiveness of 3D and 4D printing for developing intelligent systems in the biomedical sector and beyond.

Comparison of off-the-shelf β-tricalcium phosphate implants with novel resorbable 3D printed implants in mandible ramus of pigs

Facial reconstructive surgery has already implemented the use of 3D printed Patient Specific Implants derived from CAD/CAM-based technologies as an alternative to preformed bone graft substitutes. 3D-printed patient-specific implants derived from CAD/CAM-based technologies are used in facial reconstructive surgery as an alternative to preformed bone graft substitutes. However, to minimize the invasiveness and long-term adverse effects of surgical interventions, the implant needs to exhibit exact fitting, porosity, density, and volume and be made from resorbable materials that allow ingrowth and formation of new bone tissue. Therefore, we present this pilot study using 3D-printed implants consisting of pure β-TCP, produced using a novel technique that assures these properties. Eight pigs received 3D-printed truncated porous cone bone implants paired with either an off-the-shelve a chronOS (DePuy Synthes chronOS Vivify Preforms) preformed block (n = 4) or a no-implant void (n = 4) in a surgically created defect on each side of the angle of the mandible. After 6 months, CT data showed that all 3D-printed implants performed as well as did the off-the-shelve implants, with predicted osteointegration medially and laterally and with minimal gapping between the implants and native bone. The CT findings were confirmed by histological analysis that revealed that the 3D-printed implants together with the off-the-shelve implants were almost complete resorbed. Much of the resorbed volume had been replaced by vascularized compact bone, and fusion between newly formed bone and native bone was observed in all implants, further indicating that the 3D-printed implants and off-the-shelve implants performed equally well. Only soft tissue developed in the void control sites. Further studies are needed to confirm these initial findings.

Association between 3D Printing-Assisted Pelvic or Acetabular Fracture Surgery and the Length of Hospital Stay in Nongeriatric Male Adults

Pelvic and acetabular fractures are challenging for orthopedic surgeons, but 3D printing has many benefits in treating these fractures and has been applied worldwide. This study aimed to determine whether 3D printing can shorten the length of hospital stay (LHS) in nongeriatric male adult patients with these fractures. This is a single-center retrospective study of 167 nongeriatric male adult participants from August 2009 to December 2021. Participants were divided into two groups based on whether they received 3D printing assistance. Subgroup analyses were performed. Pearson’s correlation and multivariable linear regression models were used to analyze the LHS and the parameters. Results showed that 3D printing-assisted surgery did not affect LHS in the analyzed patients. The LHS was positively correlated with the Injury Severity Score (ISS). Initial hemoglobin levels were negatively associated with LHS in patients aged 18−40 and non-major trauma (ISS < 16) patients. In 40−60-year-old and non-major trauma patients, the duration from fracture to admission was significantly associated with LHS. This study indicates that 3D-assisted technology for pelvic or acetabular fracture surgery for nongeriatric male adults does not influence the LHS. More importantly, the initial evaluation of patients in the hospital was the main predictor of the LHS.

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

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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