Accidents at work by excessive efforts / inappropriate movements in nurses

Nurses continuously develop various activities that expose them to excessive force and inappropriate movements. Characterize the accidents reported by overexertion and inappropriate movements in Portuguese nurses during 2009 and 2010. Retrospective cross-sectional study, covering the period from January 1, 2009 to December 31, 2010. Were defined as inclusion criteria, be nurse and having notified by excessive straining and improper motion accident. The information was obtained by reference to the computer record of accidents at work General Administration of Health Services, relating to 672 nurses. There were 672 notifications of accidents by overexertion/ inappropriate moves in Portuguese nurses. The higher prevalence of these accidents was in nurses with over 10 years of service 277 (41.2%), 565 were female (42.6%) in the age group 25-29 (29.9%) and practice time for 555 shifts (82.6%). At admission there were 387 (57.3%) within 3 hours of work 330 (49.1%) and the third day after weekly rest 216 (32.1%). The Mobilization of patients was the most frequent cause of this accident 430 (64.0%). The main effects were the sprains and strains 321 (47.8%), mainly the trunk reached 367 (54.7%) and absenteeism caused 373 (55.5%). On average 17.7 days missed a total of 12.054 days. There was a high prevalence of accidents during the mobilization of prayer on patients so importante to invest in the implementation of mechanical equipment for the mobilization and transport of patients.

Influence of drill speed and feed rate on bone damage

Implant failures and postoperative complications are often associated to the bone drilling. Estimation and control of drilling parameters are critical to prevent mechanical damage to the bone tissues. For better performance of the drilling procedures, it is essential to understand the mechanical behaviour of bones that leads to their failures and consequently to improve the cutting conditions. This paper investigates the effect of drill speed and feed-rate on mechanical damage during drilling of solid rigid foam materials, with similar mechanical properties to the human bone. Experimental tests were conducted on biomechanical blocks instrumented with strain gauges to assess the drill speed and feed-rate influence. A three-dimensional dynamic finite element model to predict the bone stresses, as a function of drilling conditions, drill geometry and bone model, was developed. These simulations incorporate the dynamic characteristics involved in the drilling process. The element removal scheme is taken into account and allows advanced simulations of tool penetration and material removal. Experimental and numerical results show that generated stresses in the material tend to increase with tool penetration. Higher drill speed leads to an increase of von-Mises stresses and strains in the solid rigid foams. However, when the feed-rate is higher, the stresses and strains are lower. The numerical normal stresses and strains are found to be in good agreement with experimental results. The models could be an accurate analysis tool to simulate the stresses distribution in the bone during the drilling process.

Effect of different feed-rate in bone drilling: experimental and numerical study

The behaviour of bone tissue during drilling has been subject of recent studies due to its great importance. Because of thermal nature of the bone drilling, high temperatures and thermal mechanical stresses are developed during drilling that affect the process quality. However, there is still a lack information with regard to the distribution of mechanical and thermal stresses during bone drilling. The present paper describes a sequentially coupled thermal-stress analysis to assess the mechanical and thermal stress distribution during bone drilling. A three-dimensional thermo-mechanical model was developed using the ANSYS/LSDYNA finite element code under different drilling conditions. The model incorporates the dynamic characteristics of drilling process, as well as the thermo-mechanical properties of the involved materials. Experimental tests with polyurethane foam materials were also carried out. It was concluded that the use of higher feed-rates lead to a decrease of normal stresses and strains in the foam materials. The experimental and numerical results were compared and showed good agreement. The proposed numerical model could be used to predict the better drilling parameters and minimize the bone injuries.