Is This the Future of Neurovascular Microsurgical Training?

July 2, 2023

I was very honoured this year to be invited by colleagues at Universitätsklinik für Neurochirurgie, Inselspital Bern to join the faculty of their first simulation workshop on brain aneurysm microsurgery.

This was a terrific opportunity for me as well because I knew this group had been developing a very complex aneurysm surgery simulator for many years and now it was ready for primetime. But would it be any good?

I am not prone to be effusive in praise of simulation as a training tool for intracranial microsurgery at this point. As practical experience and training duration has reduced, technology start-ups have stepped into this space but claims that they deliver better, safer surgical training to what went before (and, by extension, patient outcomes) are rarely (if ever) accompanied by good quality evidence in support.

A great many factors need to be addressed in simulating the experience of carrying out a surgical procedure. Often the most useful exercises in terms of developing muscle memory for certain techniques such as suturing can be most effectively practiced on low-fidelity simulations such as a piece of fruit, chicken leg or a balloon affording multiple retakes and costing very little. Investing vast sums in technology to replicate the appearance of human anatomy unless equally successful in replicating the haptic feedback of instruments interfacing tissue or simulating the effect of breathing or heartbeat not the organ one is supposedly operating upon. Ultimately this is the difference between a high-fidelity experience close to that in the operating room and a video game.

The Bern Aneurysm Simulator- Perfused Brain Module
The perfused brain model at the heart of the Bern Simulator

I should say at this point that I have no financial relationship with the company SurgeonsLab which now produces the Bern Simulator. While they are kind enough to credit me with contributing during its development, in reality that amounted to my volunteering the sort of opinion I set out above. I knew this was going to be technologically more ambitious than other simulators I had seen and would try to address limitations I described but would that make it too complex to use or cost ineffective?

Our first day was spent familiarising me and the candidates with the machine. As an experienced surgeon the anatomical model was never going to persuade me that I was operating on a real human. The arteries didn't feel quite right and there was an alarming lack of veins. It provided a platform to consider the various ways a surgeon can apply the different shaped clips one uses to reconstruct these blood vessels and there was plenty of opportunity to interact with trainees and develop their three-dimensional thinking about clip application.

What was quite useful is that the model could be generated from the imaging of real patients with middle cerebral artery aneurysms affording the opportunity to practice the clip solution ahead of a planned procedure but also the potential to rerun the event.

What was interesting though was that blood appeared to flow through these vessels and the blood pressure and heart rate could be externally altered. If one made a hole in the blood vessel pulsatile jets of red liquid issued into the field. On the second day we started to press the candidates. I was volunteered to demonstrate how one managed the rupture of the aneurysm before one had it all the anatomy exposed one needed to arrest flow. I could sense the anxiety in my assistant as we struggled to turn this uncontrolled situation into a controlled one much to the amusement of our peers. As each of the candidates tried this scenario in turn one could see the range of responses they exhibited. The well-practiced, calm movements on a static model were replaced by hurried, unsteady movement. Breathing speeded up. Sweat appeared on more than one brow. They began to feel a little of what it is to have a procedure slip away from you. It was about managing themselves and their team more than managing the pathology.

The Bern Aneurysm Surgery Simulator

This elaborate and expensive machine simulates only one tiny element of what a neurosurgeon does in the operating room. In that sense one is not simulating "neurosurgery". But if one can simulate that feeling of control slipping away then the situation provoking that feeling perhaps matters less. It's the uncontrolled rupture of a brain aneurysm here but the same emotional response may be encountered with a carotid injury, or a swelling brain. This was the most promising step I have seen to date towards making neurosurgeons experience those emotions away from the operating room. However immersive a simulation is if it does not trigger those emotions, I suspect it has little training or clinical value. I look forward to seeing how it develops.

Under pressure as the aneurysm starts to bleed

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