Comparing mixed reality with standard computed tomography (CT) images to teach students how to assess midface fractures
| ISRCTN | ISRCTN15007079 |
|---|---|
| DOI | https://doi.org/10.1186/ISRCTN15007079 |
| Sponsors | University Hospital Zurich, University of Zurich |
| Funder | Universitätsspital Zürich |
- Submission date
- 20/10/2026
- Registration date
- 20/10/2026
- Last edited
- 20/10/2026
- Recruitment status
- No longer recruiting
- Overall study status
- Completed
- Condition category
- Other
Plain English summary of protocol
Background and study aims
Doctors assessing fractures in the middle part of the face usually examine computed tomography (CT) images on a computer screen. Mixed-reality technology allows users to view and manipulate three-dimensional images through a headset. This study compared these two approaches in a learning exercise for medical and dental students. It investigated how useful and easy to use the students found each system, how closely their fracture assessments matched an expert reference, and how much time they needed.
Who can participate?
Medical and dental students in their third to sixth year of study who had no previous knowledge of or experience with the AO CMF midface fracture classification system were eligible.
What does the study involve?
Forty students took part and were randomly allocated to one of two groups. Twenty students used a Microsoft HoloLens 2 mixed-reality headset with Lumi software, while twenty examined conventional two-dimensional CT images on a hospital computer. After a short introduction and practice example, each student assessed four previously treated fracture cases and completed a questionnaire about the imaging system.
What are the possible benefits and risks of participating?
No medical treatment was given to participants, and patient care was not changed. The study offered no direct clinical benefit. Its findings may help educators evaluate the use of three-dimensional imaging technology in medical training. Some participants using a headset reported symptoms. Patient imaging was pseudonymised before use.
Where is the study run from?
Department of Cranio-Maxillo-Facial and Oral Surgery, University Hospital Zurich, Switzerland.
When is the study starting and how long is it expected to run for?
The participant assessment sessions were completed between 14 April and 16 May 2025. Each participant attended one session, with no subsequent follow-up assessment.
Who is funding the study?
The study used departmental resources at University Hospital Zurich. The headset equipment was already owned by the department, and the software licence was purchased by the institution. No specific external research grant was received.
Who is the main contact?
Maximilian E. H. Wagner, Department of Cranio-Maxillo-Facial and Oral Surgery, University Hospital Zurich, Switzerland.
maximilian.wagner@usz.ch
Contact information
Principal investigator
University Hospital Zurich
Rämistrasse 100
Zurich
8091
Switzerland
 ORCID ID |
0000-0001-7609-9172 |
|---|---|
| Phone | +41 44 255 30 58 |
| maximilian.wagner@usz.ch |
Scientific, Public
University Hospital Zurich
Rämistrasse 100
Zurich
8091
Switzerland
| ORCID ID |
0009-0000-4822-7368 |
|---|---|
| Phone | +41 44 255 30 58 |
| maximilian.ries@usz.ch |
Study information
| Primary study design | Interventional |
|---|---|
| Allocation | Randomized controlled trial |
| Masking | Open (masking not used) |
| Control | Active |
| Assignment | Parallel |
| Purpose | Medical education and imaging-interface evaluation |
| Scientific title | Head-mounted mixed reality versus two-dimensional CT review for structured midface fracture assessment by medical and dental students: an exploratory randomised trial |
| Study objectives | The study investigated whether head-mounted mixed-reality (MR) visualisation of CT data offers more favourable learner-reported usefulness, ease of use and satisfaction than conventional two-dimensional (2D) CT review during structured midface fracture assessment. Secondary objectives were to compare agreement with a study-specific expert reference for AO CMF-derived fracture features and the time required to assess four midface fracture cases. |
| Ethics approval(s) | Ethics approval not required |
| Health condition(s) or problem(s) studied | Medical education and image-based assessment of traumatic midface fractures using computed tomography. |
| Intervention | Forty medical and dental students were allocated in pairs to one of two study groups using a simple A/B draw. One participant in each pair was assigned to mixed reality (MR) and the other to conventional two-dimensional (2D) CT review, yielding 20 participants per group. Participants and investigators were not blinded. In the MR group, participants examined pseudonymised CT-derived three-dimensional volume renderings using Lumi software on a Microsoft HoloLens 2 head-mounted display. The images could be manipulated interactively using hand gestures. In the 2D group, participants reviewed CT images on a conventional hospital monitor using DeepUnity Review version 2.0.2.2, including axial, coronal and sagittal views with standard scrolling, zooming and windowing functions. All participants received an approximately three-minute introduction to the allocated interface and completed a practice case that was excluded from the analysis. Each participant then assessed four distinct midface fracture cases randomly selected from a fixed pool of ten cases using Randomlist.org. Participants recorded fracture features and review-and-classification time for each case and completed an adapted 15-item usability questionnaire after the four assessments. Each participant attended one study session. No subsequent follow-up assessment was conducted. No clinical treatment was administered to study participants, and patient care was not affected. |
| Intervention type | Device |
| Phase | Not Applicable |
| Drug / device / biological / vaccine name(s) | Microsoft HoloLens 2; Lumi mixed-reality imaging platform; DeepUnity Review version 2.0.2.2 (active comparator). |
| Primary outcome measure(s) |
|
| Key secondary outcome measure(s) |
1. Concordance of fracture assessments with expert reference assessments measured by comparison of participant assessments with a study-specific expert reference using features derived from the AO CMF classification system (anatomical side, target region, fragmentation, displacement status, and displacement direction) during the study session for each of four midface fracture cases |
| Completion date | 16/05/2025 |
Eligibility
| Participant type(s) | |
|---|---|
| Age group | Mixed |
| Lower age limit | 18 Years |
| Upper age limit | 99 Years |
| Sex | All |
| Target sample size at registration | 40 |
| Total final enrolment | 40 |
| Key inclusion criteria | 1. Medical or dental students enrolled in the third to sixth year of their respective degree programme 2. No self-reported previous knowledge of or experience with the AO CMF midface fracture classification system 3. Ability to attend a single study session and provide oral informed consent |
| Key exclusion criteria | No additional exclusion criteria were specified beyond failure to meet the inclusion criteria |
| Date of first enrolment | 14/04/2025 |
| Date of final enrolment | 16/05/2025 |
Locations
Countries of recruitment
- Switzerland
Study participating centres
Results and Publications
| Individual participant data (IPD) Intention to share | No |
|---|
Editorial Notes
20/10/2026: Trial's existence confirmed by Kanton Ziirich Kantonale Ethikkommission.
