Time-lapse dissection videos: traditional practice in a new, digital format

Abstract

This research introduces an innovative series of time-lapse dissection videos that enable accelerated observation of the dissection process. Cadaveric dissection has consistently been described in the literature as a reliable method for enhancing student understanding and visualisation, however as a process it is expensive and extremely time-consuming, hence it is often inaccessible to learners. When active dissection is unavailable, prosections can be used to teach anatomy, however a considerable amount of spatial and structural information is lost during the dissection process. These time-lapse videos demonstrate dissection quickly and accurately and allow an irreversible process to be rewound and rewatched with flexibility. Results suggest that time-lapse offers a comprehensive and engaging view of the dissection process that students appreciate being able to observe within a concise timeframe. Written annotation, audio narration and colourful highlighting were essential inclusions following student feedback. These videos can provide instruction before dissection classes or can expose the dissection process to learners without access to cadaveric specimens. However, certain invaluable elements of practical dissection are rooted within constructivism and cannot be replicated by video. Time-lapse dissection videos should therefore be used to supplement and not replace active dissection.

Keywords:

• Cadaveric dissection
• educational videos
• time-lapse
• anatomy teaching

Introduction

The study of human anatomy is fundamental to medicine and has traditionally been taught to medical students via full body dissection. There are, however, many disciplines within healthcare and biology that have great cause to learn human anatomy, yet are unlikely to have access to cadaveric dissection. This is primarily because dissection can be a long, arduous, and expensive process. Dissection has many well-established benefits for learning, but can be criticised for its lack of accessibility and its one-directional nature, as every cut is irreversible. This can prevent dissection in large groups or in time-pressured situations from being effective (Patel et al., 2015).

Prosection-based learning is favoured as a more efficient method when time and resources do not permit full-body dissection (Dinsmore et al., 1999). Prosections give learners immediate access to internal structures and can therefore save a considerable amount of classroom time, making it more accessible within the curriculum (Granger, 2004). In addition, specimens prepared by professional anatomists are typically of much higher quality than student dissections, and can provide clearer visualisation and reveal more intricate anatomical regions.

The most notable disadvantage of prosected specimens is that a considerable amount of information is lost during the dissection process. Specimens are generally prepared to show just the ‘important’ structures of the body, such as organs, muscles and vasculature. Students are therefore unlikely to encounter the layers of connective tissues that surround these structures and bind them in place, and may have little appreciation for removed parts or relative depth. As a consequence they may lack awareness and understanding of which structures may be examined through the skin, or which are at risk during injections and in superficial injuries (Nnodim, 1990). Further, since most prosections are observed as a series of separated parts, learners may struggle to comprehend the entirety of the body’s anatomy, and learning may be considered disjointed.

This research introduced a series of time-lapse dissection videos as a method of preserving the anatomical information removed during dissection. Time-lapse photography is an effective tool for visualising events that develop too slowly to be observed in real-time (Bennett & McMillan, 2007; Liu & Li, 2012). In cadaveric dissection, the internal structures of the body are exposed manually by removal of skin, fat, and connective tissue. Even the most skilful dissector requires many hours to prepare a specimen, as great care must be taken to preserve delicate nerves and blood vessels. Accelerating cadaveric dissection via time-lapse video can therefore expose the dissection process to learners in a much faster and more accessible way.

These videos were designed to supplement learning with prosections to allow a more comprehensive understanding of the body. In addition, these videos can act as an instructional guide for performing dissection. The literature suggests that medical students do not receive enough guidance before dissection classes, and that it takes many weeks to develop proper dissection technique (Azer & Eizenberg, 2007). Initial dissections performed by students may therefore lack sufficient quality to reveal the relevant structures in a way that enhances their understanding (Flack & Nicholson, 2018). Watching these videos prior to dissecting could allow insight as to the different methods by which tissues can be exposed, and the instruments most appropriate for different procedures. They could therefore increase both the competence and confidence of students performing dissections, and could reduce anxiety caused by concerns about damaging structures (Azer & Eizenberg, 2007; Greene, 2020).

Consequently, two distinct groups of learners that could benefit from these time-lapse videos have been identified; those that do not dissect and could benefit from observing the process, and those who do dissect and need guidance on how to do so.

Advantages of time-lapse

Despite the educational benefits of videos, anatomical videos that depict real cadavers are in short supply, and there are few which effectively document the process of dissection (DiLullo et al., 2006). This is primarily because high quality dissections take many hours to complete, so watching an entire dissection from start to finish in real-time is impractical.

Several studies evaluating cadaveric dissection videos have cited video length as an issue affecting student usage. Topping (2014) for example, stated that despite popularity of their dissection videos, students critiqued them for being too long. These videos ranged from 12–50 minutes in length, and students described this as the main factor that limited how often they accessed them. In contrast, DiLullo et al. (2006) reported that students had requested longer videos of >5 minutes. Their only explanation for delivering shorter videos (1-4 minutes) was because of concerns about the download speeds available to students; a factor that is far less relevant in 2023. Both Topping (2014) and DiLullo et al. (2006) described efforts to control video length by reducing the amount of footage generated. They described filming the initial portion of dissection, then turning the camera off while the procedure was completed. By this method, segments of the dissection process are unavailable to the viewers, and information is missing compared with the in-situ experience. In contrast, Grant’s Dissection videos (yet to be evaluated in the literature) boast over 13 hours of comprehensive dissection footage to accompany their widely used dissection guide. This footage provides detailed instructions on dissection procedures in real-time, but do students really have time for this?

With time-lapse technology, the entire dissection process can be recorded, and the speed edited to suit the intricacy of the procedure. Time-lapse dissection videos therefore have the advantage of demonstrating the entire process from start to finish, without excessively increasing demands on students’ time. This method also enables students to observe a dissection of much higher quality than they could achieve themselves within allocated classroom time. Creating a time-lapse enables an experienced dissector to demonstrate their finest work without concern over the time-constraints of teaching sessions, and without having to work quickly to limit the length of the recording. Moreover, as time-lapse provides a continuous view of a single specimen being dissected, students can spend less time reorientating themselves to recognise structural relationships than they might with a series of separate specimens or images.

Most importantly, time-lapse videos could allow those without access to active dissection to gain an appreciation of the structures that may be missing from prosections or real-time dissection videos. Prosections are often missing adipose tissue, fascial layers, intermuscular septa, cutaneous nerves, superficial veins, and lymphatics. All of these are of clinical importance when it comes to understanding the cause and spread of pain and disease, but may be underappreciated by those without access to dissection.

Finally, an interesting note is that time-lapse videos might fall into the ‘oddly satisfying’ genre which has become increasingly popular on social media (Nansen & Balanzategui, 2022). Based on the frequent appearance of time-lapses within this genre, it is probable that watching an accelerated dissection would be an exciting visual novelty for students. ‘Oddly satisfying’ videos are thought to appeal to viewers due to tactile qualities, repetitive patterns or movements, and hypnotic effects achieved through editing (Nansen & Balanzategui, 2022). In popular culture, common uses for time-lapse videos include recording of construction projects and capturing natural phenomena such as wildlife or plant growth. They can provide artistic cinematic effects by accelerating periods of hours or days into minutes and seconds (Bennett & McMillan, 2007). Responses to time-lapse videos in other forms of media hints at them being more visually engaging than real-time videos, though whether they have an educational benefit is yet to be determined. This is the first contribution to the literature that explores students’ experiences with time-lapsed dissection videos, and provides some insight into their potential.

Materials and methods

Four time-lapse dissection videos were produced and shown to students to assess their validity as a novel educational resource. In addition, feedback was collected to explore how students benefit from cadaveric dissection and how passive learning by video compares with the active dissection experience. Ethical approval was granted by the Keele Institute for Innovation and Teaching Excellence Educational Research Ethics Committee (KIITE-EREC) before data collection commenced.

All cadaveric specimens included in the study were provided and approved for educational research under guidance of the Human Tissue Act 2004. All donors involved had specifically consented to their images being used. This methods section describes the content of each time-lapse video and details their production, followed by descriptions of the methods of data collection and analysis.

Time-lapse video production

Video 1 demonstrates a comprehensive dissection of the back, revealing everything from the skin down to the spinal cord. Each muscle layer was dissected in sequence, and the vertebrae and skull base were disassembled to expose the central nervous system (supplementary video clip 1). A formalin-fixed cadaver was used, which had been embalmed in prone position so as not to flatten the posterior muscles. Recording was achieved using a GoPro camera suspended in a fixed position over the cadaver, capturing images as viewed from above. This set-up can be seen in Figure 1.

Figure 1. Representation of the set-up used to record time-lapse videos 1-4. Hardware was kept at a consistent distance from each other and from the specimen. Warmth and intensity of lighting were kept consistent as fluctuations in movement and lighting are exaggerated by time-lapse and reduce video quality. Light emitting diode (LED) lights were essential to avoid a horizontal wave-form effect appearing on time-lapse footage.

The dissection took approximately 60 hours over several weeks to complete in real time. Depending on the intricacy of the structures being dissected, the camera was set to capture 1 frame every 2 or 10 seconds. Footage was then stitched together into a 30 frame per second (fps) video, thereby converting either 1 minute or 5 minutes of real-time dissection into 1 second of video. Post-production required a significant amount of editing to convert the many segments of footage into one continuous video that was 8-minutes long. No audio track or annotation were made to accompany this first time-lapse. File size: 580MB.

Videos 2–4 all depict regional dissections of one formalin-fixed cadaver. They demonstrate (2) dissection of the chest wall, (3) dissection of the anterior abdominal wall, and (4) opening of the thoracic cavity with removal of the heart and lungs.

These videos are 6, 7 and 9 minutes long, respectively. Some short sections of these videos were filmed in real-time and accelerated in post-production, as opposed to being filmed via time-lapse. This was to increase the frame rate and maintain clarity during periods of detailed, quick dissection, such as when opening the pericardial sac or cutting through the great vessels to remove the heart.

This trio of videos were all created in the same style, using an identical set-up to video 1 (Figure 1). Filming was done from a fixed angle to reduce movement, and the cadaver was positioned on a black cloth to create a neutral background and minimise distractions. These videos all feature audio narration, offering detailed descriptions of the dissection steps and of the anatomy being exposed. Narration was recorded and added to the video in post-production, scripted at an appropriate level for undergraduate medical students. This voice-over was accompanied by written annotation and brightly coloured highlighting of structures which were added to stills on screen throughout the video (Figure 2 and Supplementary video clip 2). A written list of anatomical structures to be encountered also featured at the beginning of each video. File sizes were between 440MB and 615MB.

Figure 2. Screenshots to show digital highlighting and labelling of structures. Note that post-production edits were achievable without training and with widely available software. A) Image from video 3 showing highlighting of rectus abdominus and related features. B) Image from video 4 showing great veins highlighted in blue.

Data collection

Data was collected via a multimodal approach of anonymous questionnaires and focus groups. Feedback was obtained from postgraduate physician associate students, first and second year (Y1 and Y2) pre-clinical medical students, and intercalating medical students working towards an MMedSci in anatomical sciences. Each of these cohorts had distinctly different levels of dissection experience (described below), and could therefore offer comparative perspectives on the educational relevance of these videos. All participants were recruited on a voluntary basis and were fully informed about the purpose of the research.

Physician associate students (n = 10) were selected to provide data on the unannotated time-lapse footage in video 1. The position of physician associate is relatively new within the United Kingdom, yet is an important and rapidly expanding profession within the NHS. Physician associates are described as frontline, generalist clinicians with a fundamental role in supporting doctors in the diagnosis and management of patients (Aiello & Roberts, 2017). They require a similar skillset and understanding of the human body as doctors, however at Keele University they learn only from prosections, without access to the dissection process. For this reason, they were selected to provide early data on whether time-lapse was an appropriate technique for exhibiting the dissection process. Their feedback then influenced the creation of videos 2-4 before collecting further data from additional cohorts.

Videos 2-4 were viewed and assessed by undergraduate medical students and intercalating medical students. It is important to note that this stage of research was performed during the 2020/21 academic year, when access to dissection was restricted due to the Covid-19 pandemic. Y1 medical students were still able to learn in-situ using prosections, however were not involved in the dissection process and their exposure to cadaveric resources was limited compared with previous cohorts. Y2 medical students were also restricted but had performed seven months of cadaveric dissection prior to the pandemic. Videos were therefore delivered via screen-share over Microsoft Teams. Students were given the opportunity to watch each video twice and were invited to complete an online questionnaire created with Microsoft Forms. All individual questions were optional, hence the number of responses to each question ranges from n = 35 to n = 68.

The focus group was conducted as an online video call over Microsoft Teams. Intercalating anatomists (n = 6) were selected as they had been heavily involved with elements of anatomy teaching and learning throughout the year. All had experience of dissection from their pre-clinical years and were undertaking their own dissection-based research dissertations. A focus group was chosen here as it allowed deeper exploration of the participants’ ideas and attitudes than a questionnaire.

Data analysis

Collecting both qualitative and quantitative results via questionnaires and focus groups allowed triangulation to maximise validity of the data and the analysis (Jick, 1979; McNiff, 2016). Questionnaires consisted of Likert-type items and open-ended questions. Likert-type questions were selected as they produce quantitative data that could be analysed quickly and reliably. Each question was considered a discrete item and was therefore analysed individually, not as a Likert scale (Clason & Dormody, 1994). Open-ended questions were included to collect a range of in-depth responses to supplement answers to Likert-type questions.

Statistically significant differences in quantitative data sets were determined via unpaired, two sample t-tests conducted within Microsoft Excel. All qualitative data was analysed thematically, guided by the six-stage process laid out by Braun and Clarke (2006). Coding was completed manually and by prevalence, via a semantic approach, meaning here that identification of themes relied upon explicit meanings of data, rather than making assumptions about underlying ideas (Braun & Clarke, 2006). This was to ensure that all knowledge claims were supported by evidence and that themes were an accurate representation of the entire data set. This was done to increase rigour and decrease potential biases throughout this research (Mackieson et al., 2018; McNiff, 2016).

Results

Physician associate student feedback

Physician associate students (n = 10) rate time-lapse technology highly as a method of teaching regional anatomy; 70% rated video 1 as excellent (5/5), while the remaining 30% rated it 4/5. Time-lapse was described as either ‘very’ (40%) or ‘extremely’ (50%) useful for teaching (figure 3). Other responses were ‘neutral’, and no negative responses were given.

Figure 3. Responses to the question: ‘How useful do you consider the time-lapse videos for teaching?’ n = 10.

Thematic analysis of open-ended questions confirmed that these physician associate students consider time-lapse dissection videos to be a useful resource. Criticisms and problems with use of time-lapse centre around the need for annotation to accompany these videos and clarify their content. The specific questions asked here were; ‘What do you think about using time-lapse imagery as a guide for performing dissection? Please add any criticisms or problems you can foresee with the use of time-lapse imagery? Any additional comments?’

From the feedback comments analysed, two primary themes were evident in the data. These themes were identified as ‘useful resource’ and ‘requires clarification’. Each primary theme had two associated sub-themes, as shown in the thematic map (Figure 4).

Figure 4. Thematic map showing themes and sub-themes following thematic analysis of questionnaire data. These themes relate to time-lapse video 1 and reflect feedback from physician associate students learning anatomy without access to dissection.

Useful resource

This theme was defined as including all positive comments indicating that time-lapse videos could have educational benefit for anatomy learners. There were two associated sub-themes; ‘instructive’ was established based on comments indicating that time-lapse was seen as a beneficial in guiding the dissection process. The sub-theme ‘interesting’ reflects comments indicating that this time-lapse dissection video was seen as an interesting viewing experience for those without access to dissection. Requires clarification: this theme was defined as including all comments indicating that this time-lapse video would be improved significantly with clarification of what was being shown. The sub-themes ‘needs labels’ and ‘needs commentary’ were defined based on specific requests for these forms of clarity. Table 1 shows evidence of feedback comments supporting each of these themes and their sub-themes.

Table 1. Feedback comments from physician associate students supporting the themes identified in relation to time-lapse video 1.

Examples of feedback comments supporting the theme ‘useful resource’ include:

‘Very helpful and informative’

‘The time-lapse helped me to connect my work experience [in surgery] with the anatomy lecture’

Examples of feedback comments supporting the sub-theme ‘instructive’ include:

‘I think it is a really good learning resource and would be useful in showing the dissection approach before starting a dissection class’

‘I think it would be a useful resource to prepare students beforehand’

Examples of feedback comments supporting the sub-theme ‘interesting’ include:

‘I thought it was interesting and shows anatomy in a completely different way to normal teaching’

‘It is interesting to watch if not given the opportunity to do it yourself’

Examples of feedback comments supporting the theme ‘requires clarification’ include:

‘Labelling and voice over is important for those who don’t know the particular anatomy of the body when watching the time lapse’

‘confusing to know what you are looking at and its significance’

Examples of feedback comments supporting the sub-theme ‘needs labels’ include:

‘The timelapse on its own is a good demonstration piece on how to perform dissection but without labels or audio narration it is limited on how much anatomical knowledge can be learnt’

‘It was helpful but will be more useful if labelled’

Examples of feedback comments supporting the sub-theme ‘needs commentary’ include:

‘A commentary or labelling would be useful to pinpoint structures and explain what is being performed’

‘If the videos had a commentary with them then they would be even more useful and informative’

Undergraduate medical student feedback

Y1 medical students rated time-lapse videos 2–4 highly, with an average of 9.3/10 (Figure 5). The lowest individual rating was 6/10. Students found written labels, colourful highlighting of structures, audio narration, and a list of structures encountered to be helpful additions to these videos (Figure 6). Most students believe that these time-lapse videos are a helpful educational resource that expose the dissection process in an interesting and understandable way (Figure 7). Note that the ‘very unhelpful’ (Figure 6) and ‘strongly disagree’ (Figure 7) responses were all from the same individual.

Figure 5. Graph to show the overall rating each Y1 student gave to the dissection videos ‘as an educational resource’ on a scale of 1-10, where 1 is worst and 10 is best. N = 35.

Figure 6. Y1 medical students were asked how helpful they found individual features of the videos. N = 35.

Figure 7. Y1 medical students were asked to what extent they agreed with these statements about the dissection videos. N = 35.

Y1 and Y2 medical students would appreciate access to dissection videos. 95.6% of Y1 and 79% of Y2 responded ‘yes’ to the question ‘would access to videos of the dissection process be valuable to your learning?’ (Figure 8).

Figure 8. Graph to show whether Y1 and Y2 medical students believe they would benefit from dissection videos. Y1: n = 68. Y2: n = 57.

Most medical students would prefer to be actively involved in the dissection process. 72.7% of Y1 and 70% of Y2 students responded ‘yes’ to the question ‘Given the opportunity, would you prefer to perform dissections yourself in anatomy classes?’ (Figure 9). This question was asked when access to the dissection process was unavailable due to social distancing requirements during the pandemic. Results show no significant difference between Y1 and Y2 responses.

Figure 9. Graph to show whether students would prefer to perform their own dissections during anatomy classes. Data expressed as percentage. Y1: n = 66. Y2: n = 60.

Intercalating medical student feedback

Thematic analysis of focus group data revealed four primary themes

These themes and their associated sub-themes are defined below and have been shown within the thematic map (Figure 10).

Figure 10. Thematic map showing themes and sub-themes following analysis of focus group data. These themes relate to time-lapse videos 2-4 and reflect feedback from intercalating medical students with extensive experience of dissection.

Comprehensive view of dissection

This theme was defined as including all comments that commended the time-lapse videos for displaying the full dissection process from start to finish. There were three associated sub-themes. The sub-theme ‘continuity’ was established based on comments indicating that students liked the flow and continuity offered by time-lapse. The sub-theme ‘oddly satisfying’ reflects comments that the time-lapse videos were ‘satisfying’ to view. The sub-theme ‘engaging’ reflects comments that the videos were found to be compelling to watch from start to finish. Preparation for dissection: This theme was defined as including all comments indicating that these time-lapse videos could be useful for preparing students before dissection classes. The sub-theme ‘reduce anxiety’ was established based on comments describing anxiety in dissection classes might be decreased by viewing videos of the dissection process beforehand so that students know what to expect. Concise videos are appreciated: This theme was defined as including numerous comments describing shorter videos as being preferable to longer videos. Videos cannot replace active dissection: This theme was defined as including all comments indicating that some anatomical concepts cannot be conveyed by video and must be observed and handled in-situ to gain a true understanding. Table 2 shows evidence of feedback comments supporting each of these themes and their sub-themes.

Table 2. Feedback comments from intercalating medical students supporting the themes identified in relation to time-lapse videos 2-4.

Examples of feedback comments from the theme ‘comprehensive view of dissection’ include:

‘I really liked how you showed the removal of the superficial and deep fascia before you could come across the muscles because I feel as a first year when you start dissecting you’re like, oh, there’s muscle, there’s the skin and I'm just expecting that to be just underneath it and that’s not the truth. It’s quite laborious to actually get every bit of fatty tissue out before you can start distinguishing the different layers. I also liked how you physically removed all the muscles properly rather than having a video where they were already pre-removed and just reflecting them. So I liked that you showed the entire process because that’s really helpful.’

Examples of feedback comments from the sub-theme ‘continuity’ include:

‘I really liked it when you paused it and added on labels or highlights, I liked how it continued from that specific point in time. Like there was no cut scene and then like the video started again and just give a really good sense of continuity which I thought was really cool.’

‘The thing that always used to get me with the Acland videos is that it was slow, but then it was also choppy. Because it was so slow you could tell they’d cut it down, but they’ll be like, oh now, the Pec major and minor muscles are reflected and they’d all be gone but they wouldn’t show the process. So I felt like it flowed better, which helped the pacing and also you deliver the information quicker, which I think helped as well.’

Examples of feedback comments from the sub-theme ‘satisfying’ include:

‘One thing I want to add is that it’s oddly satisfying to see all that fascia getting removed. I do like that sped up kind of version of it rather than cutting it all out. So yeah, it’s a strange point, but I think as a student it’s kind of satisfying to see all of it getting cleaned up.’

Examples of feedback comments from the sub-theme ‘engaging’ include:

‘I really liked the length, like they weren’t too long that you weren’t like Oh my God when is this going to be done, you were engaged the whole time.’

Examples of feedback comments from the theme ‘preparation for dissection’ include:

‘I think they’d be useful before we have the actual session. I think that would be a good way of giving a quick overview for a couple of minute video to actually watch someone go through it first. Then before you do it you can then see OK this is where we’re going to get to this so you can then literally just translate it across or put it up like pre reading before the session. I don’t know how many actually do pre-reading but it’s quicker than reading through textbooks. I think they’re more likely to watch a short video to revise before going into the DR as they actually know what they’re going to come across beforehand.’

Examples of feedback comments from the sub-theme ‘reduce anxiety’ include:

‘I think it can be a bit overwhelming not knowing what to do (in dissection) so I think having instructions about how to do it rather than just sort of having a go is actually useful. think that would be really easy to follow and I think it would really help. I wasn’t particularly nervous when I first did my first dissections but I think if you are a little bit unsure, I think it actually shows this is what’s going to happen.’

Examples of feedback comments from the theme ‘concise videos are appreciated’ include:

‘Before even starting the video, when I see something that says this video is 15 minutes long, you tend to look for something that’s shorter. If you see something that says 4 minutes, you’ll know that they get straight to the point of the video and you’re not going to be trying to fast forward to get to where you want to be.’

Examples of feedback comments from the theme ‘videos cannot replace active dissection’ include:

‘I always found no matter how many pictures or videos I got shown of the inguinal canal, it’s one of those things I could never get my head round, whereas I think in dissection if you can put your hand physically into it, figure out from every single angle, then you’re more likely appreciate from at least one of those different orientations, whereas with like a video or a picture you’re only ever going to get showing it from the one viewpoint, and if that’s not sinking in… so I think having it physically in front of you, you can manipulate it however you want and that’s probably the best way to learn something.’

Discussion

Overall, feedback on the time-lapse dissection videos was extremely positive. Physician associate students provided early feedback which demonstrated significant potential in time-lapse as a medium for exposing the dissection process, but also provided a clear message that without annotation its educational benefit is limited. The second set of time-lapse videos produced; videos 2–4, were enhanced by (1) adding narration, (2) adding written labels, (3) highlighting structures of importance with colour, and (4) adding a list of ‘structures to be encountered’ at the beginning of each video. These upgraded videos were rated extremely highly by medical students with an average of 9.3/10 (Figure 5), and feedback on each of these new elements was almost unanimously positive (Figure 6). Moreover, students indicated that these videos would be a useful supplementary resource, had easy to follow educational content, and could act as a suitable guide for performing dissections (Figure 7).

Discussions within the focus group supported the quantitative data of this study and identified several crucial advantages that time-lapse dissection videos have over real-time recordings. Firstly, time-lapse is superior in offering a continuous and comprehensive view of dissection. Students did not like when real-time cadaveric videos were ‘choppy’ and cut between scenes without revealing the dissection process or the connective tissue layers removed. Time-lapse has therefore been successful in displaying the entire dissection process without missing information. Secondly, results suggest that the continuous flow offered by time-lapse creates an interesting, ‘oddly satisfying’, and thus more engaging view of dissection than a real-time recording, indicating that a time-lapse video resource is more likely to be used by students.

The key difference between these time-lapse videos and existing dissection videos is of course the element of acceleration, enabling production of a concise resource. Video length has been shown to be the most significant factor affecting student engagement. A large-scale study by Guo et al. (2014), which analysed student engagement across 6.9 million watching sessions, found that students engaged best with shorter educational videos, and that content longer than 6-9 minutes is unlikely to maintain students’ concentration. This informed the current study, hence time-lapse videos were generated to be 6-9 minutes long. Length and speed of videos were discussed in the focus group, and opinions corresponded with the findings of Guo et al. (2014). It was concluded that concise videos that proceed at a good pace are more likely to be watched and are better at maintaining engagement (Table 2). These time-lapses were short, yet show entire regional dissections. This is not possible without time-lapse technology, further demonstrating the value of this medium in efficiently displaying the dissection process.

In agreement with DiLullo et al. (2006) and Greene (2020) this study recommends that videos could be useful to prepare students for dissection classes by exposing the process beforehand and providing instruction. The results here suggest that time-lapse provides a clear enough view of tools and techniques to act as a suitable dissection guide for undergraduate medical students (Figure 7), although this has yet to be tested in practice. Time-lapse videos have the advantage of being concise enough to show at the beginning of a dissection class or disseminated as a manageable quantity of pre-work.

It is important to note that the literature describes some pedagogical benefits of active dissection that are not replicable through observation alone (Darras et al., 2018; Dennis & Creamer, 2022). Displaying a practical activity by video converts a constructive learning experience into a purely cognitive one (Leppink & van den Heuvel, 2015; Mitrovic et al., 2017). If using the basic learning theories as a framework to consider how learning may occur, this change in approach fundamentally transforms how the experience may be perceived by students (Swanwick, 2010). Corresponding with this, Table 2 shows some specific examples of times when students claimed they were unable to grasp anatomical concepts by videos or textbooks, whereby physical manipulation of structures in dissection had been the only way they could understand a problem or concept. This matches the literature that describes the continued need for dissection (Memon, 2018) and relates to the hands-on benefits of the constructive learning theory.

Constructivism focusses on allowing learners to construct a scaffold of knowledge based on meaningful practical experiences, with students taking on an active role in their own learning process (Aversi-Ferreira et al., 2009; Windschitl, 1999). As dissection is primarily a practical, hands-on activity, it fits well with the ideals of this theory, and therefore shares many of its rewards. According to constructivism, learning is more meaningful to an individual when they can directly interact with a problem or concept (Windschitl, 1999). Dissection involves a significant amount of problem-solving to successfully expose and identify structures, allowing this interaction to occur in a very literal sense. The benefits of the constructivist learning theory suggest a probable limitation in the educational value of dissection videos compared to dissection in person; ultimately warning against complete replacement of active dissection with digital means. Supporting this further, this study clearly shows that the majority of Y1 and Y2 medical students would still prefer to perform their own cadaveric dissections in-situ (Figure 9).

Limitations and suggestions for future research

While this study was strengthened by integrating feedback from a range of student populations with varying levels of dissection experience, sample sizes were small and generalisability was limited. Data was all collected from the same institution and focusses solely on student perceptions. There is therefore significant scope for further research into the value of time-lapse dissection videos within anatomical education.

A significant challenge in this research was in disseminating videos containing cadaveric content. The constraints of the UK Human Tissue Authority plus those of the Coronavirus pandemic meant that students were only offered two occasions to watch each video, limiting the collectable data. Other studies, notably Greene (2020), yielded interesting results by examining how often students accessed their dissection videos over the course of an academic year. The current study lacked the capacity to do this, so an obvious next step in comparing the efficacy of time-lapse with real-time dissection videos would be to align videos to course content, trial them as instructional guides for dissection classes, and provide a more thorough evaluation of student engagement.

Most important to note is that it remains uncertain whether dissection videos have any impact on academic performance. This is not just the case for time-lapse recordings, but also for existing real-time dissection videos (DiLullo et al., 2006; Greene, 2020; Saxena et al., 2008; Topping, 2014). Exploration into impact on assessment results would be imperative to determine the true value of time-lapse in digitally exposing the full dissection process.

Conclusion

Cadaveric dissection is a time-consuming process that is restricted to staffed classroom hours within a licenced facility. It is therefore highly inaccessible. The aim of this study was to introduce a series of time-lapse dissection videos that accurately display cadaveric dissection whilst accelerating the viewing process to decrease demands on study time. It was hypothesised that these videos could have educational benefits for two distinct audiences - those without access to dissection who could benefit from observing the process, and those undertaking dissections who could benefit from additional guidance. Moreover, it was hypothesised that these videos would have distinct advantages over existing real-time dissection videos.

Feedback from a range of anatomy learners evidenced that time-lapse was perceived as a successful method of exposing the dissection process in a comprehensive, engaging and concise manner, however it was made clear that narration and written annotations are essential for providing context to time-lapse footage. Students indicated that these videos were clear enough to act as a suitable guide for performing dissections, though this has yet to be verified in practice.

This research also identified several advantageous features of practical dissection that are rooted in constructivism and cannot be replicated by video, suggesting a distinct limitation to how dissection videos should be used. Nonetheless, this study demonstrates the potential of time-lapse dissection videos as a supplementary anatomy resource and recommends further research into their implementation.

Acknowledgements

The author wishes to give thanks to the generous body donors of Keele University who consented to their images being used within these videos to enhance the learning of future healthcare professionals. The author also wishes to thank each of the students who took the time to provide constructive feedback throughout this project, particularly during the trying times of the pandemic.

Disclosure statement

No potential conflict of interest was reported by the author(s).