4.3. Tool handle design
When designing a surgical instrument, certain criteria must be fulfilled. Surgical instrument should be designed in a manner that allows ease and universality of use, durability, mass production, fast and easy sterilization, and resistance to physical and chemical agents. All surgical tools can be classified into four categories: cutting and dissecting instruments; grasping instruments; retracting instruments, and wound closing instruments and materials.51
Surgical instruments are becoming more and more complex. Therefore, designers face a challenging task to incorporate new features and achieve better performance and optimal design.52 Traditional design techniques, which are geared toward user characteristics, such as anthropometric design, do not contain sufficient data for good instrument design to best adapt to target population needs.
Minimally invasive surgical approaches significantly improve surgical results. The instrumentation has changed significantly from open to laparoscopic and robotic surgery with varying usability and ergonomic qualities.53 In order to establish guidelines for the future design of surgical instruments, it is necessary to assess the effects of current surgical approaches and surgical instruments.
Laparoscopic surgery techniques have been shown to provide major benefits to patients. However, surgeons are subjected to hard working conditions due to poor ergonomic design of instruments. A review of laparoscopic instruments reveals important design aspects.54 It is concluded that there is a need for more information on ergonomic guidelines on users’ sensory requirements during design and production of surgical instruments.
Although robotic surgery seems to remove physical discomfort during and after surgery, the results of different studies show that there is room for improvement of seating positions and control lever ergonomics. It is found that comfort and precision are the most important aspects of surgical instrument selection.53
Although the benefits of minimally invasive surgery (MIS) are undeniable, the surgeon must deal with disadvantages caused by non-regional instrument handles. Inadequate ergonomic positioning of arms and fingers can lead to pressure, nerve irritation, and rapid fatigue. Therefore, it is necessary to compare ergonomic efficiency of several different instruments’ handles used during surgery to find the most adequate solution for surgery. It should be investigated whether the position of the surgeon in relation to the patient during operation affects the use of instrument handles. Recent studies show that the shape of most used instrument handles causes users’ inconvenience and that none of currently available handles on the market meet all ergonomic criteria. The correct solution to this problem reflects the need to embrace ergonomic recommendations when designing handles for MIS instruments. It is necessary to use anatomical, physiological, and ergonomic data, as well as the results of authentic experience. On this basis, an ideal ergonomic working position for surgeons can be recommended, with optimal understanding for manipulation of instrument’s functional elements. In order to allow the surgeon to evaluate ergonomic handles for MIS instruments according to their own needs, criteria for actual „ergonomic handles“ must be introduced.55 Using ergonomic principles, providing both more intuitive instrument manipulation and a form that reduces high-pressure zones in contact with the arm of a surgeon, a new ergonomic handle design can be proposed.51 New solutions selected in this manner not only provide important ergonomic advantages, but also improve efficiency when performing tasks by reducing extreme joint movements.