Operating through the keyhole
Laparoscopic surgery offers the possibility of minimally invasive surgery through only three small skin incisions. The reflection of the abdominal cavity and the pelvic cavity is combined with the simultaneous surgical procedure. Using an endoscopic camera, the surgeon sees the surgical area on one or more screens and can thus perform the procedure in a targeted manner. Switching between different instruments for holding, cutting and coagulation make this type of surgery complex, and the limited view of the surgical field is another challenge for the surgical team. Against this background, our customer Erbe Elektromedizin has now developed a new generation of combination instrument, the TriSect rapide, in which the combined functionality of the three basic functions has been coupled with superior ergonomics. As an external partner for ergonomics and design, we were allowed to contribute our expertise.
Design and user research at the beginning
At the beginning of the project, we had to get to know laparoscopic operations and the challenges of the users. In a 2-day ergonomics workshop at the Tübingen Clinic, moderated by the Erbe in-house usability expert, we were able to try out the use of the instruments in a simulated manner and evaluate the different solutions using a wide range of different product samples available on the market. The comparative comfort tests with the users were particularly informative, because in practice the instruments are perceived and controlled almost exclusively with the sense of touch. Added to this is the sometimes unnatural hand and arm posture of the operator, sometimes over a long period of time. It therefore makes sense to design the handpiece in the direction of gripping comfort. Particularly memorable was the statement of a physician who described "the dignity of the instrument function". By this he meant that cutting into living human tissue should be associated with appropriate feedback in the surgeon's hand. A plastic housing that warps and may make crunching noises when squeezed would be a "no-go" in this respect.
Thus inspired and sensitized, the design team set about finding the shape, creating various alternative design concepts and dozens of iterative optimizations. As a multifunctional instrument, the case must pack many functions into a very small space. The installation space for the mechanical components was one challenge, the optimal fit to the hand another. At the same time, the handle had to be comfortable to use even for small hands, and all the release functions had to be easily accessible. For large hands, however, accessibility is less of a problem than possibly closed or constricted grip areas. An ergonomic shape was therefore the essence for the success of the project.
Over the course of the design process, which lasted several months, we repeatedly produced comparable samples from our 3D CAD data and had them tested. There were weeks when our 3D printers didn't stop. During the course of the design development, we were able to deliver 3D prints in all quality levels up to the near-production functional prototype.
A mature result that is worth seeing
The finished product TriSect rapide combines maximum ease of use with an effective workflow. The name already stands for this: "tri" for the three connected instruments, "sect" for "dissection tool" and "rapide" for the fast surgical workflow. The dynamically designed handle fits ideally in small and large hands and is therefore equally suitable for surgeons and female surgeons. A rotating wheel allows the shaft to be turned 360 degrees. Thanks to the ergonomic design, the finger lands directly on the probe again after a turning movement. This allows both precise gripping and sensitive opening of the angle of the branches. The thumb stabilizes and rests comfortably on a recess on the side of the instrument.
For hemostasis (thermal coagulation, hemostasis by heat), the small blue button is pressed. To cut the tissue, the handle must be pressed further. Thus, it encounters a yellow button that triggers the coagulation current flow. Compared to previous multifunctional tools, TriSect rapidly uses electricity instead of ultrasound. Since it can also be used to cut, there is acoustic feedback as well as physical - the slight resistance prevents accidental engagement of the cutting function. To cut larger areas with the pliers open, the yellow button can also be pressed individually. The selected colors, blue and yellow, are standardized colors for coagulation and cutting.
TriSect rapide is manufactured using 2K injection molding: the surfaces with which the doctor interacts or on which the hand rests have a rubbery feel and are made of TPE (thermoplastic elastomer). The shaft can be used for different applications in three different lengths and has a diameter of five millimeters. Due to the included electronics, the instrument cannot be reprocessed and is therefore a single-use product.
The brand new product has already achieved its first success: It received the red dot design award for outstanding product design in the "Medicine & Life Sciences" category in April 2023.
"Our first joint project with Erbe Elektromedizin GmbH is a successful example of close collaboration between design office and in-house engineering."
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