Mechanical engineering and delicate surgery may seem to have little in common, but the National University of Ireland, Galway, has a very active research group involving more than 40 people who seek to bring engineering expertise to the medical world.
The university has an ambitious research programme that ranges from new design methods for replacement bones to developing surgical tools and procedures.
The work is under way at the National Centre for Biomedical Engineering Science, explains Dr Peter McHugh, one of the centre's research directors. He explains: "It is a centre set up two years ago with a grant of £15.5 million from the Government via the Higher Education Authority to perform research into fundamental questions in biology, medicine and clinical treatment with a focus on interdisciplinary work."
It involves a wide spectrum of expertise, and includes doctors, engineers, life-sciences graduates and physicists. "It is all with a medical focus," says McHugh, who is also a lecturer in the university's department of mechanical engineering.
"We are mostly interested in biomechanics and biomaterials," he explains. The group's interests range far and wide, from implant devices to computer modelling of surgical procedures.
One research area involves the use of computer-aided design software to develop "engineering-assisted surgery" techniques, he says. The centre has installed one of the most powerful supercomputers in the State, which it uses to help model surgical approaches. New methods can be developed on virtual models, and outcomes can be predicted. "Computer modelling is a huge part of the whole thing," he says.
The computer can also be used to assess how, say, a bone plate or the screws and bolts that fix them will perform in the body over time. The object, says McHugh, is to "predict what will happen to the patient long-term".
The group is deeply involved in the latest methods for producing "custom-made implants" for reconstructive surgery. "It would be tremendously helpful in deformities - say after a crash, or if bone is lost through cancer."
Replacement knee and hip joints made in the tough metal titanium are available off the shelf. The Galway team wants to be able to supply custom-made replacements for damaged bones and joints. "We are developing a research capability to allow us to make titanium implants."
Part of the work involves making a replica of the patient's bone structure, a "biomodel", using advanced technologies. These physical models allow the surgeon to see exactly what might be involved in the placement of a prosthesis and helps in the design of the most suitable replacement.
The models are made in polyamide plastic from measurements derived from CT or MRI scans and accurate to a fraction of a millimetre. They are produced using "selective laser sintering", which involves building up the model layer by layer, using a laser beam that fuses together fine particles of polyamide powder.
As the layers are very thin, it could take 12 hours to produce a perfect replica of a full skull, says McHugh. It is fully automated, however, and can operate overnight, so models can be ready the next day.
The replicas are valuable to a surgeon preparing to do reconstructive surgery, he says. They give the surgeon a precise physical view of what needs to be done. The method also allows the construction of a purpose-built prothesis that matches the model.
This "rapid prototyping" is useful when treating patients who need complex bone replacements. "It is for cases where the geometry of the replacement is complicated."
Patients might include those with bone cancers where an unpredictable amount of tissue might be affected, accident victims and people with congenital deformities.
"It would allow a prosthesis to be designed directly for an individual to suit their skeletal structure," says McHugh.
Also, many titanium parts are forged, but McHugh would like to move on to casting, given the exact replicas that can be produced.