Imperial College in London are developing virtual models with haptic feedback of various clinical procedures to train medical students and professionals. In this context ‘Haptics’ – meaning touch – is the use of a computer peripheral such as a joystick that applies forces against your hand movement in relation to what you see on screen. In simulation, this allows you to physically feel virtual three dimensional shapes. Haptics can vary from a vibrating joystick, to a full sensory purpose-made interface.
An example of the type of haptic device used by Imperial College. The device provides ‘force-feedback’ to your finger as you interact with a 3D on-screen model.
In order to create a virtual model for gynaecological examinations, Dr Fernando Bello, who leads the team at Imperial College, asked us to create a realistic physical model. It had to be realistic in that it had to ‘feel’ like the real thing, where as for this application it did not have to look particularly realistic. However there was one further challenge: the inside of the model needed to be largely transparent, so that internal cameras could track the trainee’s finger movements.
Experimenting with cameras and transparent materials to record movements inside the simulation
By creating a model that closely mimicked the anatomy of a gynaecological examination, and by being able to watch what happened from inside, Imperial College researchers are able to use tiny digital pressure sensors to track what happens when gynaecologist performs an examination and compare this data with the movements they can see through the cameras.
A gynecological examination usually involves an attempt to identify the ovaries by squeezing them between the internally placed finger tips, and by pressing firmly on the patient’s tummy from above. To do this, the ovaries need to be pushed upwards in to a suitable position. If the ovaries are normal, it is sometimes very difficult to identify them.
This was a key part of the procedure that we needed to simulate. In order to know what it should feel like Studiohead designers participated in gynaecological training with Gynaecological Training Assistants (GTAs). These assistants are experts in knowing how an examination should feel when administered on themselves, and are able to guide trainees on how to do an examination correctly. GTAs are a sought after resource and not available to most trainees, however the experience was essential for us to be able to recreate the correct sensations.
One result of the training was a realisation that instead of trying to replicate the anatomy of the uterus and ovaries as they normally lie in a rested position, we needed to position the ovaries as if they were already pushed up against the tummy wall – the position in which you can feel them. This allowed us to get the sensations correct, while also clearing the view for the internal cameras inside the model.
An early iteration using stitched silicone sheet and clear acrylic to make the model transparent.
The model is constructed with clear acrylic supports that represent the bone structure. We then made early prototypes out of stitched transparent silicone sheet before refining the models with molded clear silicone painted on in layers to achieve the desired stiffness.
We also created a very realistic external front piece to the model, which we have decided is too realistic to put on our website in fear of being filtered by search engines.
This project took a lot of trial and error with experienced gynaecologists assessing our model (blind-folded) and feeding back to us on each iteration. Eventually we achieved a high level of realism that will help the Imperial College team to increase access to good quality gynaecology simulation.