Design and evaluation of a new ergonomic handle for instruments in minimally invasive surgery.

BACKGROUND: Laparoscopic surgery techniques have been demonstrated to provide massive benefits to patients. However, surgeons are subjected to hardworking conditions because of the poor ergonomic design of the instruments. In this article, a new ergonomic handle design is presented. This handle is designed using ergonomic principles, trying to provide both more intuitive manipulation of the instrument and a shape that reduces the high-pressure zones in the contact with the surgeon's hand. MATERIALS AND METHODS: The ergonomic characteristics of the new handle were evaluated using objective and subjective studies. The experimental evaluation was performed using 28 volunteers by means of the comparison of the new handle with the ring-handle (RH) concept in an instrument available on the market. The volunteers' muscle activation and motions of the hand, wrist, and arm were studied while they performed different tasks. The data measured in the experiment include electromyography and goniometry values. RESULTS: The results obtained from the subjective analysis reveal that most volunteers (64%) preferred the new prototype to the RH, reporting less pain and less difficulty to complete the tasks. The results from the objective study reveal that the hyperflexion of the wrist required for the manipulation of the instrument is strongly reduced. CONCLUSIONS: The new ergonomic handle not only provides important ergonomic advantages but also improves the efficiency when completing the tasks. Compared with RH instruments, the new prototype reduced the high-pressure areas and the extreme motions of the wrist.

Accurate estimation of airborne ultrasonic time-of-flight for overlapping echoes.

In this work, an analysis of the transmission of ultrasonic signals generated by piezoelectric sensors for air applications is presented. Based on this analysis, an ultrasonic response model is obtained for its application to the recognition of objects and structured environments for navigation by autonomous mobile robots. This model enables the analysis of the ultrasonic response that is generated using a pair of sensors in transmitter-receiver configuration using the pulse-echo technique. This is very interesting for recognizing surfaces that simultaneously generate a multiple echo response. This model takes into account the effect of the radiation pattern, the resonant frequency of the sensor, the number of cycles of the excitation pulse, the dynamics of the sensor and the attenuation with distance in the medium. This model has been developed, programmed and verified through a battery of experimental tests. Using this model a new procedure for obtaining accurate time of flight is proposed. This new method is compared with traditional ones, such as threshold or correlation, to highlight its advantages and drawbacks. Finally the advantages of this method are demonstrated for calculating multiple times of flight when the echo is formed by several overlapping echoes.

Ultrasonic sensors in urban traffic driving-aid systems.

Currently, vehicles are often equipped with active safety systems to reduce the risk of accidents, most of which occur in urban environments. The most prominent include Antilock Braking Systems (ABS), Traction Control and Stability Control. All these systems use different kinds of sensors to constantly monitor the conditions of the vehicle, and act in an emergency. In this paper the use of ultrasonic sensors in active safety systems for urban traffic is proposed, and the advantages and disadvantages when compared to other sensors are discussed. Adaptive Cruise Control (ACC) for urban traffic based on ultrasounds is presented as an application example. The proposed system has been implemented in a fully-automated prototype vehicle and has been tested under real traffic conditions. The results confirm the good performance of ultrasonic sensors in these systems.