Reshaping the future of sinus surgery
In preparation for any operation, the correct training and the highest level of accuracy is essential. Jo Lumani speaks to Dr Russell Harris, from the Wolfson School of Mechanical and Manufacturing Engineering, about how medical simulation models can save lives.
It’s a field where precision is key, where a millimetre’s movement in the wrong direction could cause major internal injury or even death. The job of a surgeon is certainly not an easy one and although surgical techniques have advanced considerably over the last few decades, any advanced training procedures should surely be seen as a positive step for the future of patient care.
Dr Russell Harris, from the Department of Mechanical and Manufacturing Engineering, is leading a four-man Loughborough University team aiming to make a tangible difference in the training techniques for surgery, in particular sinus operations, which require high precision and carry a significant risk of damage to critical organs.
Working with the Nottingham University Hospitals NHS Trust, Dr Harris has developed medical simulation models to help lessen the risk associated with complex sinus operations and ultimately increase patient safety.
Now in its third year, the EPSRC Innovative Manufacturing and Construction Research Centre-funded research has been investigating design and production techniques to produce realistic physical surgery models of the sinus to allow the enactment and evaluation of different surgical cases.
"We’ve been working very closely with the NUH in Nottingham, with work to date focussing on the sinus,” said Dr Harris.
"They have a number of remits within the hospital, one of which is producing models when surgeons want to evaluate different individual cases. We wanted to push the boundaries beyond what was currently available and Mr Anshul Sama, from Head and Neck Surgery at the NUH, was very receptive to this.
"Sinus surgery is extremely complex and also very risky. There’s a possibility of damaging the optic nerve and the muscles of the eye, as well as the brain, which is very close by. Parts of the sinus are only one or two millimetres from the brain cavity, so if you penetrate that, there will be cerebral fluid loss and possibly risk of meningitis. Critically, the carotid artery runs in the peripheral wall of the sinuses and there can be serious implications if damaged."
"They need to train surgeons in these complicated areas and minimally invasive endoscopic techniques are becoming much more popular. The clinical skills required are really quite extensive and presently, surgeons are constrained by the very limited training models available, which are primarily simple rubber representations which don’t show much detail, or using cadavers. There are lots of different restrictions with cadavic models – ethically, logistically, availability – but the biggest problem is that the properties are not similar to that of a live patient.
"With the new European working time directive for junior doctors now in force, the BMA and other organisations, most notably the Royal College of Surgeons, have expressed concerns that junior doctor training will suffer. Simulation models such as the ones produced by Loughborough University will address these implications by introducing greater scope and efficacy to enable focussed training in a reduced timescale."
The models, which are manufactured using an Additive Manufacturing technique, replicate the appearance and physicality of the human sinus during surgery and are able to prepare doctors fully for the complexities of different clinical scenarios.
"The challenge for us is being able to get the actual physical properties required because the sinus is very unique and there is lots of variability in the physicality due to its composition of both hard and soft tissue. Also, the structures themselves would be considered, certainly in an engineering sense, to be weak.
Our models are now very close to biological samples and we are now able to integrate some of them in clinical teaching. It has come on a long way in a very short space of time.
"Their properties wouldn’t be desirable in many other engineering concepts, when you actually need to make structures strong or tougher. In these medical simulation models for the sinus, we are trying to make something which is selectively weak, like a real sinus, so it can simulate accidental damage during the surgery and all of the different characteristics."
The research team comprises Dr Russell Harris, Dr Darren Watts, Matteo Gatto and Richard Taylor from the Wolfson School of Engineering; Mr Anshul Sama and Mr Jason Watson of NUH; with support from patient support charity ‘Let’s Face It’ and Z-Corporation, who specialise in 3D printing systems.
The simulation models are designed by reverse-engineering the data from MRI and CT scans.
"We did some pilot work looking at how we could use some of our techniques which allow us to take electronic representations, in this case the CT or the MRI scan, which we then reproduce physically and analyse the material properties.
One of the main requirements is to be able to produce the physical properties of the bone alongside the soft tissue elements. We started off with a process which already has similar material elements to bone and then we had to do a lot of work tailoring the properties of the end product to give us those which we experienced in surgery. One of the very unique things we have done is produced a lot of work in characterising the physical conditions themselves during surgery.
"The training models have progressed well and Matteo has just taken over some of our samples to a training course which was conducted in Copenhagen by Mr Sama. We are beginning to see the fruit of some of our efforts directly translated into some of the models. Our models are very close to biological samples and we are now able to integrate some of them in clinical teaching. It has come on a long way in a very short space of time."
Dr Harris says that the next step for the research is ‘mission rehearsal’ – where exact cases can be replicated, to allow clinicians to practice on specific individual cases before actual surgery takes place.
"We have concentrated a lot on the training to date and we are now producing various different case examples. We are going to assess how quickly we can turn around a physical representation of a patient-specific case. If everything is in place then theoretically, we could do it in 24 hours. That will be a big advantage to the process because as soon as you have got the data, the actual production of the model is a fairly automated process which operates with very little human intervention. We then conduct some processing on the model after we receive it, before it is used. This would also be relatively cheap – possibly below £100 for a model – compared to what is currently available."
The possibilities for this kind of simulation model do not stop at the sinus, with Dr Harris underlining that ultimately, this technique could also help with surgical training on other areas of the body.
"We started deliberately on a very difficult area. There are lots of complications in the physical properties of the sinus and a high risk of damage, but if you can utilise these techniques in this area, then potentially we can move onto lots of different clinical areas in the body.
"That’s something we are currently looking at. For example, you have orthopaedics, where the properties are very different, but our techniques are applicable to all of them. Neuro and cardio surgery are the other big areas.
"What we have really done to date is establish the feasibility of this research in a single clinical discipline. The potential value of this work is much further ranging – we want to get it into further clinical areas to demonstrate the applicability of the techniques.
I’ve personally been working in a clinical setting now for seven years and the boundaries that we have overcome - by collaborating directly with key personnel - has been really quite extensive. The medical and clinical requirements are completely different from other applications of additive manufacturing.
Most of all, our research and these simulation models are capable of making a tangible difference to not only doctors, but also the patients’ lives.
Want to know more?
- Website: www.lboro.ac.uk/amrg
- Contact: Dr Russell Harris
- Tel: 01509 227571
- Email: R.A.Harris@lboro.ac.uk
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