Effect of laparoscopic handle size on surgical performance: A randomized crossover trial.

Laparoscopic instrument handles design and dimensions are crucial to determine the configuration of surgeons' hand grip and, therefore, can have a deleterious effect on overall surgical efficiency and surgeons' comfort. The aim of this study is to investigate the impact of laparoscopic handle size and hand surface area on surgical task performance. A single-blind, randomized crossover trial was carried out with 29 novice medical students. Participants performed three simulated tasks in "black box" simulators using two scissor-type handles of different sizes. Surgical performance was assessed by the number of errors and time required to complete each task. Hand anthropometric data were measured using a 3D scanner. Execution time was significantly higher when cutting and suturing tasks were performed with the smaller handle. In addition, hand surface area was positively correlated with peg transfer task time when performed with the standard handle and was correlated with cutting task time in small and standard handle groups. We also found positive correlations between execution time and the number of errors executed by larger-handed participants. Our findings indicate that laparoscopic handle size and hand area influence surgical performance, highlighting the importance of considering hand anthropometry variances in surgical instrument design.

Human factors related to the use of a personal computer: A case study.

The aim of this study was to determine and compare the ergonomic requirements in the use of desktop computers and laptops. For comparison, postures in the sagittal and transversal planes involved while performing a typing and editing task on a desktop and laptop computers were verified. Thus, a case study was conducted with a Brazilian male of medium height, who works around 20 hours per week in a computer. Nine spherical markers of 2.5 cm in diameter were joined up with duct tape on the right side of the participant and the positions adopted by the subject were analyzed in the use of a desktop and a laptop computer, through direct observation and filming, using the videography technique. It is concluded that the use of desktop computers has lesser biomechanical demands since it showed angles closer to a neutral position and consequently having a lower risk of musculoskeletal complaints.

How to integrate ergonomics into product design through the user centered design approach.

BACKGROUND: Ergonomics/Human factors (HFE) is little considered in the engineering design practice and design methodologies do not adequately present the use of HFE. OBJECTIVE: The aim of this paper is to propose a systematic for the integration of HFE into product design, based on the user-centered design approach. Thus, an overview of the systematic is presented, as well as the suggestion of methods and support tools for each phase of the design process. METHODS: In order to verify the applicability of the systematic it was done an expert evaluation of the systematic and an experiment was carried out in the engineering education, in two classes of the product design course in a Brazilian University in 2016. RESULTS: The results showed that the students of the study group developed a better knowledge about HFE and its use in product design, besides the probability of using HFE in the product design went from low to high after the experiment. CONCLUSION: Presenting this information in a systematized way together with the design process allows students to be more likely to use it, to understand it better and know how to use it.

Postmen activity's analysis.

This study examines the postmen activity and the bag used in their task, which should transport the weight without affecting the locomotor system and the attitude of the worker. Studies were conducted on the activity of the postmen and transportation of loads, analyzing functional and ergonomic aspects of load distribution, as well as surveys with users, which made it possible to verify and prove the problems presented. Thus, the following work was developed in order to demonstrate the importance of applying an ergonomic product design.