PhD student Durandus Vonck developed a vacuum tool that allows surgeons in keyhole surgery to get a grip on tissue without damaging it.
The development of the vacuum grasper was a typical example of design by research, says Professor Richard Goossens (Industrial Design Engineering) who supervised Vonck’s PhD research. The project fell within the research framework that the IDE faculty has with the German laparoscopic instrument builder Karl Storz GmbH. Vonck not only produced a novel and practical design but also several publications along the way.
“We had regular meetings with Storz’s daughter in Tübingen”, says Goossens, who appreciates the freedom of exploratory research that Storz allowed. “It was only in the end that they took over the design to optimise it for production and for use in the operation theatre.”
It all began with the idea of using vacuum for getting a grip on tissue during an operation. Tools that have been in use for that are basically modified pincers, which are prone to damage the tissue if not handled correctly. Amongst other studies, Dr. Eveline Heijnsdijk showed this in a PhD research project (2004) at the faculty of 3mE.
To test the feasibility of a vacuum grasper for the delicate tissue of the bowels, Vonck set out for tests on pig’s guts. Several degrees of vacuum were applied while the tissue was drawn up to test the strength of the grip. Later the tissue was inspected for damage as a result of the treatment.
After some 160 test-manipulations, only four proved not successful. In other words: the tissue slipped. And as for the vacuum – it proves to be pretty harmless even down to 3 kPa (100 kPa is atmospheric pressure). In some cases small haemorrhages occurred, which – like a hickey – spontaneously blew over after some time. The reason why even deep vacuum hasn’t more adverse effects, is that at a given pressure, tissue completely fills the suction cup of the instrument after which a deeper vacuum doesn’t affect it. This means that even non-expert handling of the instrument cannot cause damage. It’s idiot-proof.
So much for patient security, but how about the doctors? The instrument should be easy to handle without causing stresses and cramps for the surgeons. The user group said they would prefer a manual vacuum over a connection to the vacuum pipe on the operation room. Obviously, this allows the operators more freedom of movement, but can you actually generate enough vacuum by hand?
No less than five IDE master students worked on the design of the vacuum pump handle. “The first design looked like a hair blower”, Goossens remembers. “After that, it gradually became more elegant until Storz took over to optimise the design for manufacturing.” Another clever adaptation they introduced was to place the vacuum piston in the tight shaft instead of in the wider handle.
In 2011, four years after Vonck started with his PhD research project, Storz got the CE-mark on its medically approved device – the laparoscopic vacuum grasper. An instrument that has been tested on the bowel, but may also be applied to liver, spleen and gallbladder.
Goossens has enjoyed working with Storz, and is glad that they have taken up the instrument to bring it to market. He knows from previous projects that without the proper channels your instrument, however clever it might be, is unlikely to reach its users.
–> Durandus Vonck, The feasibility of vacuum technique in minimal invasive surgery – improving the patient safety through instrument design, 24 April 2013, PhD supervisors Prof. Richard Goossens and Prof. Jack Jakimowicz (IDE).
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