Abstract
Purpose
As the amount of curricular material required of medical students increases, less time is available for anatomy; thus, methods to teach anatomy more efficiently and effectively are necessary. In this randomized controlled trial, we looked at the effectiveness of a mixed reality (MR) device to teach musculoskeletal anatomy to medical students compared with traditional cadaveric dissection.
Method
Participating students were divided into three cohorts. Cohort 1 first studied upper limb anatomy in MR followed by lower limb anatomy through cadaveric dissection. Cohort 2 studied upper limb anatomy with cadaveric dissection followed by lower limb anatomy in MR. After the six sessions, a third cohort of 33 students who never received any teaching in MR was recruited to participate in the final practical exams as a control group. All 64 students completed two practical exams with equivalent content, one in the cadaver lab and one using MR.
Results
The average scores were 73.8% + 12.3 on the cadaver exam and 74.2% + 13.0 in MR. There is no statistical difference between these scores (p > 0.05). A correlation was found between the MR practical exam and cadaver practical exam scores (r = 0.74, p < 0.01) across all students.
Conclusions
To our knowledge, this study marks the first time that MR was compared with traditional anatomy learning modalities in a multi-session, group course. Our results clearly indicate that medical students, regardless of the study modality, performed similarly on the MR and the cadaver practical exams.
Keywords: Medical education, Anatomy, Mixed reality, Virtual reality, HoloLens
Introduction
Anatomical knowledge is generally accepted as important in medical education and, for over 400 years, cadaveric dissection has been employed to teach this essential topic [1]. In a study by Arraez-Aybar et al., practicing medical professionals identified human anatomy as the most relevant basic science discipline for daily clinical practice [2].
Until very recently, dissection, along with lectures and other didactics, was the main method for teaching anatomy to medical students [3]. As the amount of health sciences content required of medical students increases, less curricular time is available for anatomy; thus, methods to teach anatomy more efficiently and effectively are necessary [4]. A number of modalities have appeared to supplement and even replace cadaveric dissection in anatomy education. From simple web-based quizzes and images to advanced 3D technology, computer-assisted learning in anatomy education has become an essential element in student learning [4]. Throughout the world, medical schools have invested time and effort into expanding these resources. Students today can view a 3D skeleton in great detail using an anatomy app on their mobile phones or enter into a virtual reality (VR) chamber to experience virtual anatomy at a level of sophistication unimaginable less than a generation ago [4].
Because of recent advances in technology, the use of virtual/augmented/mixed reality has blossomed into a viable option for medical education programs to supplement anatomy learning [5]. The term “mixed reality” (MR) refers to head mounted displays that overlay virtual objects onto a user’s environment. These typically use holographic projectors to place an image directly on the wearer’s retina, giving the appearance of physical objects in the real world. The first widely available version of this was produced by Microsoft in 2015 and is called Microsoft HoloLens [5].
In the present study, we looked at the effectiveness of an MR device to teach musculoskeletal anatomy to medical students compared with traditional cadaveric dissection. In this randomized controlled trial, students were assigned to either a cadaver or MR lab for a portion of the trial. At the culmination of the trial, each student took two lab practical exams to assess anatomic knowledge: one lab practical based in MR and another lab practical based in cadaver dissection. An additional cohort, which studied the entirety of the material only via cadaveric dissection, was also assessed on both modalities.
Methods
Study Design
A prospective randomized controlled study was conducted during the fall of 2017, with second-year medical students at Case Western Reserve University School of Medicine (CWRU SoM), Cleveland, OH, USA.
An email was sent to the second-year medical school class to recruit volunteers for the study. All students had previous dissection experience in earlier portions of the gross anatomy and radiology courses. For convenience purposes, existing dissection groups were asked to volunteer as a unit. Inclusion criteria were (1) the anatomy group had to consist of four students; (2) all group members had to agree to volunteer for the study and sign an informed consent document; (3) attendance was required at all lab sessions; (4) all students had to agree to complete pre- and post-quizzes during each lab session in order to maintain a consistent response rate; (5) each participant had to agree to complete two anatomy lab practical exams at the end of the course, one using MR and another using cadavers in the dissection lab.
Each anatomy group consisted of four members. Any group with one or more members who had previously taken courses in human anatomy were excluded from the study. All students had dissection experience during their first year of medical school when they were required to dissect the thoracic, abdominal, and pelvic regions. The second-year medical students who participated in this study had no previous exposure to musculoskeletal anatomy. Due to a limitation in the number of available MR devices, only four dissection groups (sixteen students) could participate in the intervention at once. Of the thirty-one anatomy groups which volunteered to participate in the study, 12 anatomy groups were eligible after application of the exclusion criteria and eight of these groups were randomly selected using a random number generator to participate in the intervention. Informed consent was obtained from all individual participants included in the study.
The study was reviewed by the CWRU Institutional Review Board (IRB) and deemed exempt under 45 Code of Federal Regulations (CFR) part 46.101(b) (1). This includes any investigation conducted in established or commonly accepted educational settings, involving normal educational practices, such as research on regular and special education instructional strategies, or research on the effectiveness of or the comparison among instructional techniques, curricula, or classroom management methods.
Anatomical Models
Over a period of 18 months, a team of CWRU-based biomedical artists and anatomy faculty created the MR anatomical models (Fig. 1) used in this study. These custom models were created using 3D modeling software (primarily 3ds Max, Autodesk) in order to meet the competing goals of conveying anatomical information at the highest resolution possible, while maintaining the ability to display this information in a completely mobile device with limited processing power. Microsoft HoloLens devices were the MR devices used for visualization of the models.
Fig. 1.
An example of an anatomical model
MR Classroom Infrastructure
In order to mimic the dissection lab configuration, students remained in their dissection groupings during the MR sessions. Each student wore his or her own MR device. A content expert was present to answer questions. The four groups were positioned at four locations in a room at one time. Given the goal of replicating small group learning in the MR setting, we developed a custom networking and display software package that allowed all 16 students in an MR group to see the same content and participate in the learning exercise at the same time. In this study, the material for each class was designed like a conventional computer presentation (similar to a PowerPoint presentation) where a set of anatomical models was displayed sequentially. One MR device acted as a server that sent out information on the currently displayed content to each individual student’s device. Since the MR devices are untethered from a computer, each student was free to walk around the model and view it from their own vantage point. Student groups and individuals were also able to independently access the device with the software application to review material on their own.
Intervention
Individual class sessions were designed in MR to duplicate the content of the cadaver dissection labs. There were six 2-h cadaveric dissections in the standard curriculum that covered the anatomy of the upper and lower limbs.
Participating students were divided into three cohorts. Two of the cohorts (cohort 1 and cohort 2) consisted of four dissection groups. Initially, there were 16 students in each cohort, but one student from cohort 1 was disqualified from the study due to unexcused absences. Cohort 1 first studied upper limb anatomy in MR followed by lower limb anatomy through cadaveric dissection. Cohort 2 studied upper limb anatomy with cadaveric dissection followed by lower limb anatomy in MR (Fig. 2). Teaching assistants and anatomy faculty were available during all lab sessions (MR and cadaver) to answer questions. After the six sessions, a third cohort of 33 students who never received any teaching in MR was recruited to participate in the final practical exams as a control group. No exclusion criteria existed for cohort 3. All 64 students completed two practical exams with equivalent content, one in the cadaver lab and one using MR, on the same day. The students received the higher of their two exam scores as their final practical exam grade.
Fig. 2.
Division of students into cohorts showing the anatomy that was learned on each modality
Materials and Data Collection
The process of creating equivalent MR lab guides occurred in several steps. First, one of the researchers created a PowerPoint-like MR presentation based on the existing cadaveric dissection guides. Next, these presentations were revised and assembled into parallel lab guides tailored to MR anatomy. Finally, a content expert reviewed these presentations for consistency.
The MR application recorded the amount of time spent by students using the application for study both in and out of the scheduled lab time. Students in the cadaver lab were required to attend each of the three 2-h dissection periods. In addition, students were asked to record their study time in the dissection lab in a pocket notebook.
To ensure anonymity, each study participant created a unique identifier for use on all study-related materials. All study participants had unrestricted access to the MR devices as well as the cadaver labs.
In order to enable comparison between the cohorts, equivalent 60-min MR and cadaver-based practical exams were created and administered on the same day. Exam questions were standardized and included first- and second-order questions addressing both structure identification and related characteristics such as function and innervation. Each practical exam consisted of two short answer questions per station and students were allotted 1 min and 15 s at each station. The MR practical exam consisted of 36 upper limb and 36 lower limb questions. The cadaver practical exam comprises 39 upper limb and 39 lower limb questions. Ten and seven rest stations were interspersed during the MR and cadaver exams, respectively, to enable students to catch up and relax momentarily. Exam questions were standardized and of comparable difficulty to anatomy questions asked in other medical schools in the USA, Canada, and Israel. Anatomy department staff graded de-identified exams. Cohort assignment was not known during the grading process.
Results
Thirty-one of the thirty-two participants in the intervention groups completed all six dissections. All of the students in cohorts 1, 2, and 3 completed a final anatomy written exam and two practical exams, one in the dissection lab and one using MR.
The amount of time spent using the MR devices was recorded automatically. Students logged an average of 3.6 h in MR for both required lab time (2.8 h) and study time (0.8 h) over the three lab periods. Students were required, per the curriculum, to be in each cadaveric dissection lab for three, 2-h dissection sessions totaling 6 h (without considering out-of-class study time because it could not be accurately recorded). Thus, less curricular time was required to cover the same content when using the MR devices. No time information was available for cohort 3 other than the required six, 2-h dissection sessions.
The average scores were 73.8% + 12.3 on the cadaver exam and 74.2% + 13.0 in MR. There is no statistical difference between these scores (p > 0.05). Individual students’ overall practical exam scores for MR vs. cadaver practical exams were compared and a regression analysis was performed (Fig. 3). A correlation was found between the MR practical exam and cadaver practical exam scores (r = 0.74, p < 0.01) across all students.
Fig. 3.
Comparison of student (n = 64) performance on the cadaver-based and MR practical exams
Discussion
This study shows that students who learn musculoskeletal anatomy using MR technology appear to perform as well on an anatomy practical as they do when taught using cadaveric dissection. Less curricular time was required to teach using MR (3.6 h compared with 6). This implies that the MR device may be equally effective but more efficient for teaching musculoskeletal anatomy. The results of this study demonstrate the potential positive impact that these technologies can have on the future of anatomy education. To our knowledge, this study marks the first time that MR was compared with traditional anatomy learning modalities in a multi-session, group course. Our results clearly indicate that medical students, regardless of the study modality, performed similarly on the MR and the cadaver practical exams. While this does not indicate superiority of one modality over another, it does suggest potential equivalence in communicating anatomical material. This study did not examine potential synergies between the use of MR and cadaveric dissection, but this is a clear potential for future research.
There is no doubt that cadaveric dissection is of value to medical students particularly in the early years of their professional training. Benefits include “development of cognitive anatomical knowledge and its vocabulary, appreciation of 3D relationships and anatomical variability, and participating in peer-group learning. Skill-based benefits include developing fine motor control, and attitudinal benefits include establishing the primacy of the patient, promoting professionalism, and promoting attitudes conducive to team working” [6]. Many students come in direct contact with a deceased human body for the very first time when they enter the dissection lab, which provides a safe space to reflect on topics such as death and donation (body or organ). Many of these invaluable benefits are unavailable through computer-based programs.
On the other hand, many claim that cadaveric dissection has its limitations, which may be partially overcome with MR technology. Maintenance of a cadaver lab is costly and time consuming. Moreover, it requires body donors in addition to staffing and facilities to support it [7]. Prosection is considered by some as a viable alternative to cadaveric dissection that provides the tactile input and exposure to anatomical variation without requiring the time necessitated by student dissection [8, 9]. Prosection, however, is not always possible due to storage limitations, preparation requirements, and number of specimens necessary for a large group of students. While MR technologies do often require dedicated technical support by staff, they have advantages over cadaveric dissection and prosection in that they can be utilized in almost any facility and can be re-used an infinite number of times. The cost of an MR lab requires a one-time investment for the technology and is highly dependent on the number of students in the class. While the initial cost may be substantial, dissection labs are expensive to maintain, and require the use of hazardous chemical preservatives [10–12].
The limitations of our study include the small sample size and no robust recorded data on the amount of time spent in the cadaver lab outside of the required 6 h of dissection time. An important strength of this study is its design, with very clear inclusion and exclusion criteria. Lastly, each MR lab guide was created to be equivalent in content to the cadaveric dissection guide and the two practical exams at the end of the block were matched in content and difficulty to decrease the possibility of bias and other confounding factors.
This study is a critical step in understanding the utility and effectiveness of MR in anatomy education. These results demonstrate that medical students can learn anatomical structures at the same level using MR as cadaveric dissection. Thus, technologies such as MR may offer a viable alternative for learning this material, in particular for students who lack access to cadaveric dissection facilities, or even as a way to increase efficiency for students with access to a dissection lab.
Author Contributions
Stojanovska M., Medical Student, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
Contributions: substantial contributions to conception and design, acquisition of data, and analysis and interpretation of data, drafting the article and revising it critically for important intellectual content, provided final approval of the paper, agreed to be accountable for all aspects of the work, gave final approval to the submitted paper.
Tingle G., Senior 3D Artist, Interactive Commons, Case Western Reserve University, Cleveland, OH, 44106, USA
Contributions: substantial contributions to conception and design, revising the article critically for important intellectual content, provided final approval of the paper, agreed to be accountable for all aspects of the work, gave final approval to the submitted paper.
Tan L., 3D Artist, Interactive Commons, Case Western Reserve University, Cleveland, OH, 44106, USA
Contributions: substantial contributions to conception and design, revising the article critically for important intellectual content, provided final approval of the paper, agreed to be accountable for all aspects of the work, gave final approval to the submitted paper.
Ulrey L., 3D Artist, Interactive Commons, Case Western Reserve University, Cleveland, OH, 44106, USA
Contributions: substantial contributions to conception and design, revising the article critically for important intellectual content, provided final approval of the paper, agreed to be accountable for all aspects of the work, gave final approval to the submitted paper.
Simonson-Shick S. M.S., Instructional Designer, Case Western Reserve University, Cleveland, OH, 44106, USA
Contributions: substantial contributions to conception and design, revising the article critically for important intellectual content, provided final approval of the paper, agreed to be accountable for all aspects of the work, gave final approval to the submitted paper.
Mlakar J., Assistant Director of Visualization, Interactive Commons, Case Western Reserve University, Cleveland, OH, 44106, USA
Contributions: substantial contributions to conception and design, revising the article critically for important intellectual content, provided final approval of the paper, agreed to be accountable for all aspects of the work, gave final approval to the submitted paper.
Eastman H., Senior Visualization Technology Developer, Case Western Reserve University, Cleveland, OH, 44106, USA
Contributions: substantial contributions to conception and design, revising the article critically for important intellectual content, provided final approval of the paper, agreed to be accountable for all aspects of the work, gave final approval to the submitted paper.
Gotschall R., Senior Visualization Technology Developer, Interactive Commons, Case Western Reserve University, Cleveland, OH, 44106, USA
Contributions: substantial contributions to conception and design, revising the article critically for important intellectual content, provided final approval of the paper, agreed to be accountable for all aspects of the work, gave final approval to the submitted paper.
Boscia A. M.S., Medical Student, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
Contributions: substantial contributions to conception and design, revising the article critically for important intellectual content, provided final approval of the paper, agreed to be accountable for all aspects of the work, gave final approval to the submitted paper.
Enterline, R. M.S., Research Associate, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
Contributions: substantial contributions to conception and design, acquisition of data, revising the article critically for important intellectual content, provided final approval of the paper, agreed to be accountable for all aspects of the work, gave final approval to the submitted paper.
Henninger E. M.B.A., Executive Director, Interactive Commons, Case Western Reserve University, Cleveland, OH, 44106, USA
Contributions: substantial contributions to conception and design, revising the article critically for important intellectual content, provided final approval of the paper, agreed to be accountable for all aspects of the work, gave final approval to the submitted paper.
Herrmann KA. M.D. Ph.D., Associate Professor of Anatomy University Hospitals Cleveland Medical Center, Cleveland, OH, 44106, USA
Contributions: substantial contributions to conception and design, drafting the article and revising it critically for important intellectual content, provided final approval of the paper, agreed to be accountable for all aspects of the work, gave final approval to the submitted paper.
Simpson S.W. Ph.D., Professor, Department of Anatomy, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
Contributions: substantial contributions to conception and design, acquisition of data, and analysis and interpretation of data, drafting the article and revising it critically for important intellectual content, provided final approval of the paper, agreed to be accountable for all aspects of the work, gave final approval to the submitted paper.
Griswold MA. Ph.D., Professor of Radiology, Faculty Director, Interactive Commons, Case Western Reserve University, Cleveland, OH, 44106, USA
Contributions: substantial contributions to conception and design, acquisition of data, and analysis and interpretation of data, drafting the article and revising it critically for important intellectual content, provided final approval of the paper, agreed to be accountable for all aspects of the work, gave final approval to the submitted paper.
Wish-Baratz S. Ph.D. M.B.A., Associate Professor of Anatomy, Director of HoloAnatomy Interactive Commons, Case Western Reserve University, Cleveland, OH, 44106, USA
Contributions: substantial contributions to conception and design, acquisition of data, and analysis and interpretation of data, drafting the article and revising it critically for important intellectual content, provided final approval of the paper, agreed to be accountable for all aspects of the work, gave final approval to the submitted paper.
Footnotes
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