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Student Learning Experience with 3D Printed Models and Plated Samples: A Qualitative Analysis | BMC Medical Education

        Traditional cadaver dissection is on the decline, while plastination and 3D printed (3DP) models are gaining popularity as an alternative to traditional anatomy teaching methods. It is not clear what the strengths and weaknesses of these new tools are and how they might affect students’ anatomy learning experience, which includes such human values ​​as respect, care, and empathy.
        Immediately after the randomized cross-over study, 96 students were invited. A pragmatic design was used to explore learning experiences using anatomically plasticized and 3D models of the heart (Stage 1, n=63) and neck (Stage 2, n=33). An inductive thematic analysis was performed based on 278 free text reviews (referring to strengths, weaknesses, areas for improvement) and verbatim transcripts of focus groups (n = 8) about learning anatomy using these tools.
       Four themes were identified: perceived authenticity, fundamental understanding and complexity, attitudes of respect and care, multimodality, and leadership.
       In general, students felt that the plastinated specimens were more realistic and therefore felt more respected and cared for than the 3DP models, which were easier to use and better suited for learning basic anatomy.
        Human autopsy has been a standard teaching method used in medical education since the 17th century [1, 2]. However, due to limited access, high costs of cadaver maintenance [3, 4], a significant reduction in anatomy training time [1, 5], and technological advances [3, 6], anatomy lessons taught using traditional dissection methods are in decline. This opens up new possibilities for researching new teaching methods and tools, such as plastinated human specimens and 3D printed (3DP) models [6,7,8].
        Each of these tools has pros and cons. The plated specimens are dry, odorless, realistic and non-hazardous [9,10,11], making them ideal for teaching and engaging students in the study and understanding of anatomy. However, they are also rigid and less flexible [10, 12], so they are thought to be more difficult to manipulate and reach deeper structures [9]. In terms of cost, plasticized samples are generally more expensive to purchase and maintain than 3DP models [6,7,8]. On the other hand, 3DP models allow different textures [7, 13] and colors [6, 14] and can be assigned to specific parts, which helps students more easily identify, distinguish and remember important structures, although this seems less realistic than plasticized samples.
        A number of studies have examined the learning outcomes/performance of various types of anatomical instruments such as plasticized specimens, 2D images, wet sections, Anatomage tables (Anatomage Inc., San Jose, CA) and 3DP models [11, 15, 16, 17, 18, 19, 20, 21]. However, the results differed depending on the choice of training instrument used in the control and intervention groups, as well as depending on different anatomical regions [14, 22]. For example, when used in combination with wet dissection [11, 15] and autopsy tables [20], students reported higher learning satisfaction and attitudes towards plastinated specimens. Similarly, the use of plastination patterns reflects the positive outcome of students’ objective knowledge [23, 24].
        3DP models are often used to supplement traditional teaching methods [14,17,21]. Loke et al. (2017) reported on the use of the 3DP model to understand congenital heart disease in a pediatrician [18]. This study showed that the 3DP group had higher learning satisfaction, better understanding of Fallot’s tetrad, and improved ability to manage patients (self-efficacy) compared to the 2D imaging group. Studying the anatomy of the vascular tree and the anatomy of the skull using 3DP models provides the same learning satisfaction as 2D images [16, 17]. These studies have shown that 3DP models are superior to 2D illustrations in terms of student-perceived learning satisfaction. However, studies specifically comparing multi-material 3DP models with plasticized samples are limited. Mogali et al. (2021) used the plastination model with its 3DP heart and neck models and reported a similar increase in knowledge between control and experimental groups [21].
        However, more evidence is needed to gain a deeper understanding of why student learning experience depends on the choice of anatomical instruments and different parts of the body and organs [14, 22]. Humanist values ​​are an interesting aspect that can influence this perception. This refers to the respect, care, empathy and compassion expected from students who become doctors [25, 26]. Humanistic values ​​have traditionally been sought in autopsies, as students are taught to empathize with and care for donated corpses, and therefore the study of anatomy has always occupied a special place [27, 28]. However, this is rarely measured in plasticizing and 3DP tools. Unlike closed-ended Likert survey questions, qualitative data collection methods such as focus group discussions and open-ended survey questions provide insight into participant comments written in a random order to explain the impact of new learning tools on their learning experience.
       So this research aimed to answer how do students perceive anatomy differently when they are given set tools (plastination) versus physical 3D printed images to learn anatomy?
        To answer the above questions, students have the opportunity to acquire, accumulate and share anatomical knowledge through team interaction and collaboration. This concept is in good agreement with the constructivist theory, according to which individuals or social groups actively create and share their knowledge [29]. Such interactions (for example, between peers, between students and teachers) affect learning satisfaction [30, 31]. At the same time, the learning experience of students will also be influenced by factors such as learning convenience, environment, teaching methods, and course content [32]. Subsequently, these attributes can influence student learning and mastery of topics of interest to them [33, 34]. This may be related to the theoretical perspective of pragmatic epistemology, where the initial harvest or formulation of personal experience, intelligence, and beliefs can determine the next course of action [35]. The pragmatic approach is carefully planned to identify complex topics and their sequence through interviews and surveys, followed by thematic analysis [36].
        Cadaver samples are often considered silent mentors, as they are seen as significant gifts for the benefit of science and humanity, inspiring respect and gratitude from students to their donors [37, 38]. Previous studies have reported similar or higher objective scores between the cadaver/plastination group and the 3DP group [21, 39], but it was unclear whether students share the same learning experience, including humanistic values, between the two groups. For further research, this study uses the principle of pragmatism [36] to examine the learning experience and characteristics of 3DP models (color and texture) and compare them with plastinated samples based on student feedback.
        Student perceptions can then influence educators’ decisions about choosing appropriate anatomy tools based on what is and is not effective for teaching anatomy. This information can also help educators identify student preferences and use appropriate analysis tools to improve their learning experience.
        This qualitative study aimed to explore what students consider to be an important learning experience using plasticized heart and neck samples compared to 3DP models. According to a preliminary study by Mogali et al. in 2018, students considered plastinated specimens to be more realistic than 3DP models [7]. So let’s assume:
       Given that plastinations were created from real cadavers, students were expected to view plastinations more positively than 3DP models in terms of authenticity and humanistic value.
        This qualitative study is related to two previous quantitative studies [21, 40] because the data presented in all three studies were collected simultaneously from the same sample of student participants. The first article demonstrated similar objective measures (test scores) between the plastination and 3DP groups [21], and the second article used factor analysis to develop a psychometrically validated instrument (four factors, 19 items) to measure educational constructs such as learning satisfaction, self-efficacy, humanistic values, and learning media limitations [40]. This study examined high-quality open and focus group discussions to find out what students consider important when learning anatomy using plastinated specimens and 3D printed models. Thus, this study differs from the previous two articles in terms of research objectives/questions, data, and analysis methods to gain insight into qualitative student feedback (free text comments plus focus group discussion) on the use of 3DP tools compared to plasticized samples. This means that the present study fundamentally solves a different research question than the two previous articles [21, 40].
        At the author’s institution, anatomy is integrated into systemic courses such as cardiopulmonary, endocrinology, musculoskeletal, etc., in the first two years of the five-year Bachelor of Medicine and Bachelor of Surgery (MBBS) program. Plastered specimens, plastic models, medical images, and virtual 3D models are often used in place of dissection or wet dissection specimens to support general anatomy practice. Group study sessions replace the traditional lectures taught with a focus on the application of acquired knowledge. At the end of each system module, take an online formative anatomy practice test that includes 20 individual best answers (SBAs) covering general anatomy, imaging, and histology. In total, five formative tests were conducted during the experiment (three in the first year and two in the second year). The combined comprehensive written assessment for Years 1 and 2 includes two papers, each containing 120 SBAs. Anatomy becomes part of these assessments and the assessment plan determines the number of anatomical questions to be included.
        In order to improve the student-to-sample ratio, internal 3DP models based on plastinated specimens were studied for teaching and learning anatomy. This provides an opportunity to establish the educational value of new 3DP models compared to plastinated specimens before they are formally included in the anatomy curriculum.
        In this study, computed tomography (CT) (64-slice Somatom Definition Flash CT scanner, Siemens Healthcare, Erlangen, Germany) was performed on plastic models of the heart (one whole heart and one heart in cross section) and head and neck (one whole and one midsagittal plane head-neck) (Fig. 1). Digital Imaging and Communications in Medicine (DICOM) images were acquired and loaded into 3D Slicer (versions 4.8.1 and 4.10.2, Harvard Medical School, Boston, Massachusetts) for structural segmentation by type such as muscles, arteries, nerves, and bones. The segmented files were loaded into Materialize Magics (Version 22, Materialize NV, Leuven, Belgium) to remove the noise shells, and the print models were saved in STL format, which were then transferred to an Objet 500 Connex3 Polyjet printer (Stratasys, Eden Prairie, MN) to create 3D anatomical models. Photopolymerizable resins and transparent elastomers (VeroYellow, VeroMagenta and TangoPlus) harden layer by layer under the action of UV radiation, giving each anatomical structure its own texture and color.
        Anatomy study tools used in this study. Left: Neck; right: plated and 3D printed heart.
        In addition, the ascending aorta and coronary system were selected from the whole heart model, and base scaffolds were constructed to attach to the model (version 22, Materialize NV, Leuven, Belgium). The model was printed on a Raise3D Pro2 printer (Raise3D Technologies, Irvine, CA) using thermoplastic polyurethane (TPU) filament. To show the model’s arteries, the printed TPU support material had to be removed and the blood vessels painted with red acrylic.
        First-year Bachelor of Medicine students at the Lee Kong Chiang Faculty of Medicine in the 2020-2021 academic year (n = 163, 94 males and 69 females) received an email invitation to participate in this study as a voluntary activity. The randomized cross-over experiment was performed in two stages, first with a heart incision and then with a neck incision. There is a six week washout period between the two stages to minimize residual effects. In both stages, students were blind to learning topics and group assignments. No more than six people in a group. Students who received plastinated samples in the first step received 3DP models in the second step. At each stage, both groups receive an introductory lecture (30 minutes) from a third party (senior teacher) followed by self-study (50 minutes) using the provided self-study tools and handouts.
       The COREQ (Comprehensive Criteria for Qualitative Research Reporting) checklist is used to guide qualitative research.
        Students provided feedback on the research learning material through a survey that included three open-ended questions about their strengths, weaknesses, and opportunities for development. All 96 respondents gave free-form answers. Then eight student volunteers (n = 8) took part in the focus group. Interviews were conducted at the Anatomy Training Center (where the experiments were conducted) and were conducted by Investigator 4 (Ph.D.), a male non-anatomy instructor with over 10 years of TBL facilitation experience, but not involved in the study team training. The students did not know the personal characteristics of the researchers (nor the research group) prior to the start of the study, but the consent form informed them of the purpose of the study. Only researcher 4 and students participated in the focus group. The researcher described the focus group to the students and asked them if they would like to participate. They shared their experience of learning 3D printing and plastination and were very enthusiastic. The facilitator asked six leading questions to encourage students to work through (Supplementary Material 1). Examples include discussion of aspects of anatomical instruments that promote learning and learning, and the role of empathy in working with such specimens. “How would you describe your experience of studying anatomy using plastinated specimens and 3D printed copies?” was the first question of the interview. All questions are open-ended, allowing users to answer questions freely without biased areas, allowing new data to be discovered and challenges to be overcome with learning tools. Participants received no recording of comments or analysis of the results. The voluntary nature of the study avoided data saturation. The entire conversation was taped for analysis.
        The focus group recording (35 minutes) was transcribed verbatim and depersonalized (pseudonyms were used). In addition, open-ended questionnaire questions were collected. Focus group transcripts and survey questions were imported into a Microsoft Excel spreadsheet (Microsoft Corporation, Redmond, WA) for data triangulation and aggregation to check for comparable or consistent results or new results [41]. This is done through theoretical thematic analysis [41, 42]. Each student’s text answers are added to the total number of answers. This means that comments containing multiple sentences will be treated as one. Replies with nil, none or no comments tags will be ignored. Three researchers (a female researcher with a Ph.D., a female researcher with a master’s degree, and a male assistant with a bachelor’s degree in engineering and 1–3 years of research experience in medical education) independently inductively encoded unstructured data. Three programmers use real drawing pads to categorize post-it notes based on similarities and differences. Several sessions were conducted to order and group codes through systematic and iterative pattern recognition, whereby codes were grouped to identify subtopics (specific or general characteristics such as positive and negative attributes of learning tools) which then formed overarching themes [41]. To reach consensus, a 6 male researcher (Ph.D.) with 15 years of experience in teaching anatomy approved the final subjects.
        In accordance with the Declaration of Helsinki, the Institutional Review Board of Nanyang Technological University (IRB) (2019-09-024) evaluated the study protocol and obtained the necessary approvals. Participants gave informed consent and were informed of their right to withdraw from participation at any time.
        Ninety-six first-year undergraduate medical students provided full informed consent, basic demographics such as gender and age, and declared no prior formal training in anatomy. Phase I (heart) and Phase II (neck dissection) involved 63 participants (33 men and 30 women) and 33 participants (18 men and 15 women), respectively. Their age ranged from 18 to 21 years (mean ± standard deviation: 19.3 ± 0.9) years. All 96 students answered the questionnaire (no dropouts), and 8 students took part in focus groups. There were 278 open comments about pros, cons, and needs for improvement. There were no inconsistencies between the analyzed data and the report of findings.
        Throughout the focus group discussions and survey responses, four themes emerged: perceived authenticity, fundamental understanding and complexity, attitudes of respect and caring, multimodality, and leadership (Figure 2). Each topic is described in more detail below.
        The four themes—perceived authenticity, fundamental understanding and complexity, respect and care, and preference for learning media—are based on thematic analysis of open-ended survey questions and focus group discussions. The elements in the blue and yellow boxes represent the properties of the plated sample and the 3DP model, respectively. 3DP = 3D printing
        The students felt that the plastinated specimens were more realistic, had natural colors more representative of real cadavers, and had finer anatomical details than the 3DP models. For example, muscle fiber orientation is more prominent in plasticized samples compared to 3DP models. This contrast is shown in the statement below.
       ”…very detailed and accurate, like from a real person (C17 participant; free-form plastination review).”
        The students noted that the 3DP tools were useful for learning basic anatomy and assessing major macroscopic features, while the plasticized specimens were ideal for further expanding their knowledge and understanding of complex anatomical structures and regions. The students felt that although both instruments were exact replicas of each other, they were missing valuable information when working with 3DP models compared to plastinated samples. This is explained in the statement below.
       “…there were some difficulties like… small details like fossa ovale… in general a 3D model of the heart can be used… for the neck, maybe I will study the plastination model more confidently (participant PA1; 3DP, focus group discussion”).
       ”…gross structures can be seen… in detail, 3DP specimens are useful for studying, for example, coarser structures (and) larger, easily identifiable things like muscles and organs… perhaps (for) people who may not have access to plastinated specimens (PA3 participant; 3DP, focus group discussion)”.
        The students expressed more respect and concern for the plastinated specimens, but were also concerned about the destruction of the structure due to its fragility and lack of flexibility. On the contrary, students added to their practical experience by realizing that 3DP models could be reproduced if damaged.
       ”… we also tend to be more careful with plastination patterns (PA2 participant; plastination, focus group discussion)”.
        “…for plastination specimens, it’s like…something that has been preserved for a long time. If I damaged it… I think we know it looks like more serious damage because it has a history (PA3 participant; plastination, focus group discussion).”
       ”3D printed models can be produced relatively quickly and easily…making 3D models accessible to more people and facilitating learning without having to share samples (I38 contributor; 3DP, free text review).”
       “…with 3D models we can play around a bit without worrying too much about damaging them, like damaging samples… (PA2 participant; 3DP, focus group discussion).”
        According to the students, the number of plastinated specimens is limited, and access to deeper structures is difficult due to their rigidity. For the 3DP model, they hope to further refine the anatomical details by tailoring the model to areas of interest for personalized learning. Students agreed that both plasticized and 3DP models can be used in combination with other types of teaching tools such as the Anatomage table to enhance learning.
       ”Some deep internal structures are poorly visible (participant C14; plastination, free-form comment).”
       ”Perhaps autopsy tables and other methods would be a very useful addition (member C14; plastination, free text review).”
       “By making sure the 3D models are well detailed, you can have separate models focusing on different areas and different aspects, such as nerves and blood vessels (participant I26; 3DP, free text review).”
       Students also suggested including a demonstration for the teacher to explain how to properly use the model, or additional guidance on annotated sample images to facilitate study and understanding in lecture notes, although they acknowledged that the study was specifically designed for self-study.
       ”…I appreciate the independent style of research…perhaps more guidance could be provided in the form of printed slides or some notes…(participant C02; free text comments in general).”
       ”Content experts or having additional visual tools such as animation or video can help us better understand the structure of 3D models (member C38; free text reviews in general).”
        First-year medical students were asked about their learning experience and the quality of the 3D printed and plasticized samples. As expected, the students found the plasticized samples to be more realistic and accurate than the 3D printed ones. These results are confirmed by a preliminary study [7]. Since the records are made from donated corpses, they are authentic. Although it was a 1:1 replica of a plastinated specimen with similar morphological characteristics [8], the polymer-based 3D printed model was considered less realistic and less realistic, especially in students in whom details such as the edges of the oval fossa were not visible in the 3DP model of the heart compared to the plastinated model. This may be due to the quality of the CT image, which does not allow clear delineation of the boundaries. Therefore, it is difficult to segment such structures in segmentation software, which affects the 3D printing process. This can raise doubts about the use of 3DP tools as they fear that important knowledge will be lost if standard tools such as plasticized samples are not used. Students interested in surgical training may find it necessary to use practical models [43]. The current results are similar to previous studies that found that plastic models [44] and 3DP samples do not have the accuracy of real samples [45].
        In order to improve student accessibility and therefore student satisfaction, the cost and availability of tools must also be considered. The results support the use of 3DP models for gaining anatomical knowledge due to their cost-effective fabrication [6, 21]. This is consistent with a previous study that showed comparable objective performance of plasticized models and 3DP models [21]. Students felt that 3DP models were more useful for studying basic anatomical concepts, organs, and features, while plastinated specimens were more suitable for studying complex anatomy. In addition, students advocated the use of 3DP models in conjunction with existing cadaver specimens and modern technology to improve students’ understanding of anatomy. Multiple ways to represent the same object, such as mapping the anatomy of the heart using cadavers, 3D printing, patient scans, and virtual 3D models. This multi-modal approach allows students to illustrate anatomy in different ways, communicate what they have learned in different ways, and engage students in different ways [44]. Research has shown that authentic learning materials such as cadaver tools can be challenging for some students in terms of the cognitive load associated with learning anatomy [46]. Understanding the impact of cognitive load on student learning and applying technologies to reduce cognitive load to create a better learning environment is critical [47, 48]. Before introducing students to cadaveric material, 3DP models can be a useful method to demonstrate basic and important aspects of anatomy in order to reduce cognitive load and enhance learning. In addition, students can take the 3DP models home for review in combination with textbooks and lecture materials and expand the study of anatomy beyond the lab [45]. However, the practice of removing 3DP components has not yet been implemented in the author’s institution.
        In this study, plastinated samples were more respected than 3DP replicas. This conclusion is consistent with previous research showing that cadaveric specimens as the “first patient” command respect and empathy, while artificial models do not [49]. Realistic plastinated human tissue is intimate and realistic. The use of cadaveric material allows students to develop humanistic and ethical ideals [50]. In addition, students’ perceptions of plastination patterns may be affected by their growing knowledge of cadaver donation programs and/or the plastination process. Plastination is donated cadavers that mimic the empathy, admiration and gratitude that students feel for their donors [10, 51]. These characteristics distinguish humanistic nurses and, if cultivated, can help them advance professionally by appreciating and empathizing with patients [25, 37]. This is comparable to silent tutors using wet human dissection [37,52,53]. Since the specimens for plastination were donated from cadavers, they were viewed as silent tutors by the students, which earned respect for this new teaching tool. Even though they know that 3DP models are made by machines, they still enjoy using them. Each group feels cared for and the model is handled with care to preserve its integrity. Students may already know that 3DP models are created from patient data for educational purposes. At the author’s institution, before the students begin the formal study of anatomy, an introductory anatomy course on the history of anatomy is given, after which the students take an oath. The main purpose of the oath is to instill in students an understanding of humanistic values, respect for anatomical instruments, and professionalism. The combination of anatomical instruments and commitment can help instill a sense of caring, respect, and perhaps remind students of their future responsibilities towards patients [54].
        In regards to future improvements in learning tools, students from both the plastination and 3DP groups incorporated the fear of structure destruction into their participation and learning. However, concerns about the disruption of the structure of plated specimens were highlighted during the focus group discussions. This observation is confirmed by previous studies on plasticized samples [9, 10]. Structure manipulations, especially neck models, are necessary to explore deeper structures and understand three-dimensional spatial relationships. The use of tactile (tactile) and visual information helps students form a more detailed and complete mental picture of three-dimensional anatomical parts [55]. Studies have shown that tactile manipulation of physical objects can reduce cognitive load and lead to better understanding and retention of information [55]. It has been suggested that supplementing 3DP models with plasticized specimens can improve student interaction with the specimens without fear of damaging the structures.

Post time: Jul-21-2023