A Sensorized Instrument for Minimally Invasive Surgery for the Measurement of Forces during Training and Surgery: Development and Applications

The reduced access conditions present in Minimally Invasive Surgery (MIS) affect the feel of interaction forces between the instruments and the tissue being treated. This loss of haptic information compromises the safety of the procedure and must be overcome through training. Haptics in MIS is the subject of extensive research, focused on establishing force feedback mechanisms and developing appropriate sensors. This latter task is complicated by the need to place the sensors as close as possible to the instrument tip, as the measurement of forces outside of the patient\u27s body does not represent the true tool--tissue interaction. Many force sensors have been proposed, but none are yet available for surgery. The objectives of this thesis were to develop a set of instruments capable of measuring tool--tissue force information in MIS, and to evaluate the usefulness of force information during surgery and for training and skills assessment. To address these objectives, a set of laparoscopic instruments was developed that can measure instrument position and tool--tissue interaction forces in multiple degrees of freedom. Different design iterations and the work performed towards the development of a sterilizable instrument are presented. Several experiments were performed using these instruments to establish the usefulness of force information in surgery and training. The results showed that the combination of force and position information can be used in the development of realistic tissue models or haptic interfaces specifically designed for MIS. This information is also valuable in order to create tactile maps to assist in the identification of areas of different stiffness. The real-time measurement of forces allows visual force feedback to be presented to the surgeon. When applied to training scenarios, the results show that experience level correlates better with force-based metrics than those currently used in training simulators. The proposed metrics can be automatically computed, are completely objective, and measure important aspects of performance. The primary contribution of this thesis is the design and development of highly versatile instruments capable of measuring force and position during surgery. A second contribution establishes the importance and usefulness of force data during skills assessment, training and surgery

Force/position-based modular system for minimally invasive surgery,”

Abstract-The limitations of minimally invasive surgery include the inability to sense forces exerted by the instruments on tissue and the limited visual cues available through the endoscope. A modular laparoscopic instrument capable of measuring force and position has been designed to address these limitations. Novel image-based position tracking software has been developed and integrated within a graphical user interface. This modular system is low cost, versatile, and could be used for training, localization of critical features or for guidance during surgical procedures

Energy-based metrics for arthroscopic skills assessment

Minimally invasive skills assessment methods are essential in developing efficient surgical simulators and implementing consistent skills evaluation. Although numerous methods have been investigated in the literature, there is still a need to further improve the accuracy of surgical skills assessment. Energy expenditure can be an indication of motor skills proficiency. The goals of this study are to develop objective metrics based on energy expenditure, normalize these metrics, and investigate classifying trainees using these metrics. To this end, different forms of energy consisting of mechanical energy and work were considered and their values were divided by the related value of an ideal performance to develop normalized metrics. These metrics were used as inputs for various machine learning algorithms including support vector machines (SVM) and neural networks (NNs) for classification. The accuracy of the combination of the normalized energy-based metrics with these classifiers was evaluated through a leave-one-subject-out cross-validation. The proposed method was validated using 26 subjects at two experience levels (novices and experts) in three arthroscopic tasks. The results showed that there are statistically significant differences between novices and experts for almost all of the normalized energy-based metrics. The accuracy of classification using SVM and NN methods was between 70% and 95% for the various tasks. The results show that the normalized energy-based metrics and their combination with SVM and NN classifiers are capable of providing accurate classification of trainees. The assessment method proposed in this study can enhance surgical training by providing appropriate feedback to trainees about their level of expertise and can be used in the evaluation of proficiency

CONSENSO SOBRE O USO DE PROTEÍNA EM PACIENTES CRÍTICOS – ACNC

The critical patient has a significant loss of muscle mass, frequently observing sarcopenia in these patients. Its presence increases adverse outcomes, hospital stays, increased risk of infections, increased time on mechanical ventilatory assistance, greater disability at hospital discharge, less possibility of return to normal life for patients, increased health costs, and higher mortality. Objective: Indicate the opportune and adequate use of the protein in the critically ill patient. Methods: the Colombian Association of Clinical Nutrition (ACNC) and the Colombian Association of Critical Medicine and Intensive Care (AMCI), using a consensus methodology, made recommendations with a group of experts. Results: 46 recommendations were approved with a consensus greater than 80%. Conclusions: Optimal early and progressive protein intervention in critically ill patients is important to obtain the best clinical outcomes, reduce complications, and have an impact on hospital care costs.El paciente crítico tiene una pérdida de masa muscular significativa, observando frecuentemente sarcopenia en estos pacientes. Su presencia aumenta los desenlaces adversos, estancias hospitalarias, mayor riesgo de infecciones, aumento del tiempo de asistencia ventilatoria mecánica, mayor discapacidad al alta hospitalaria, menor posibilidad del retorno normal a la vida habitual de los pacientes, incremento en gastos en salud y mayor mortalidad. Objetivo: Indicar el uso oportuno y adecuado de la proteína en el paciente crítico. Métodos: la Asociación Colombiana De Nutrición Clínica (ACNC) y la Asociación Colombiana de Medicina Critica y Cuidados Intensivos (AMCI) mediante metodología de consenso realizaron unas recomendaciones con un grupo de expertos. Resultados: 46 recomendaciones fueron aprobadas con consenso superior al 80%. Conclusiones: La intervención óptima proteica temprana y progresiva en el paciente crítico, es importante para obtener los mejores desenlaces clínicos, disminuir complicaciones e impactar en costos de atención hospitalaria. O paciente crítico apresenta perda importante de massa muscular, observando-se frequentemente sarcopenia nesses pacientes. Sua presença aumenta os desfechos adversos, internações hospitalares, aumento do risco de infecções, aumento do tempo de assistência ventilatória mecânica, maior incapacidade na alta hospitalar, menor possibilidade de retorno à vida normal dos pacientes, aumento dos custos de saúde e maior mortalidade. Objetivo: Indicar o uso oportuno e adequado da proteína no paciente crítico. Métodos: a Associação Colombiana de Nutrição Clínica (ACNC) e a Associação Colombiana de Medicina Crítica e Terapia Intensiva (AMCI), utilizando uma metodologia de consenso, fizeram recomendações com um grupo de especialistas. Resultados: 46 recomendações foram aprovadas com consenso superior a 80%. Conclusões: A intervenção proteica precoce e progressiva ideal em pacientes críticos é importante para obter os melhores resultados clínicos, reduzir complicações e impactar nos custos hospitalares

CONSENSO SOBRE EL USO DE PROTEÍNA EN EL PACIENTE CRÍTICO – ACNC

El paciente crítico tiene una pérdida de masa muscular significativa, observando frecuentemente sarcopenia en estos pacientes. Su presencia aumenta los desenlaces adversos, estancias hospitalarias, mayor riesgo de infecciones, aumento del tiempo de asistencia ventilatoria mecánica, mayor discapacidad al alta hospitalaria, menor posibilidad del retorno normal a la vida habitual de los pacientes, incremento en gastos en salud y mayor mortalidad. Objetivo: Indicar el uso oportuno y adecuado de la proteína en el paciente crítico. Métodos: la Asociación Colombiana De Nutrición Clínica (ACNC) y la Asociación Colombiana de Medicina Critica y Cuidados Intensivos (AMCI) mediante metodología de consenso realizaron unas recomendaciones con un grupo de expertos. Resultados: 46 recomendaciones fueron aprobadas con consenso superior al 80%. Conclusiones: La intervención óptima proteica temprana y progresiva en el paciente crítico, es importante para obtener los mejores desenlaces clínicos, disminuir complicaciones e impactar en costos de atención hospitalaria.

Feasibility study of a moving hand support for surgery on the beating heart

A method for performing coronary bypass surgery on the beating heart is proposed, and entails the use of a heart-tracking support to move the hands of the surgeon in synchrony with the heart motion. This method eliminates the damaging effects associated with stopping or stabilizing the heart, while preserving the surgeon's dexterity and accuracy. First, a feasibility study was performed in order to compare the accuracy attained and the completion time required to perform accurate tasks on stable and moving targets, both with and without a motion tracking support. The results demonstrate that the negative effects of the target motion, namely, decreased accuracy and increased task completion time, are considerably reduced with the use of the support. The use of both monocular and stereo vision systems that provide a stable view of the work space was shown to limit the increase in task completion time; however, the accuracy was not improved due to the low resolution of the vision systems used. A solution to the design of the moving hand support consists of a three degree of freedom mechanism with prismatic joints. For this mechanism to accurately track the heart, it is necessary to measure the motion of the surgical area in real-time and to generate a suitable control strategy. After comparing several sensors that could be used to measure the heart motion, a mechanical sensor was designed and built. Despite the measurement error present in this particular prototype, it is believed that the design features of the sensor make it a suitable solution to the heart tracking problem. In order to address the problem of motion control, the moving support system was simulated using SIMULINK® and implemented on an experimental setup with PID and computed torque control. Furthermore, an additional control strategy is proposed that facilitates tracking of quasiperiodic, quantized inputs. Results show that it is possible for the mechanism to accurately follow the trajectory of the heart surface, since the maximum tracking error is approximately 0.15 mm.Applied Science, Faculty ofMechanical Engineering, Department ofGraduat

Evaluating Muscle Activation Models for Elbow Motion Estimation

Adoption of wearable assistive technologies relies heavily on improvement of existing control system models. Knowing which models to use and how to improve them is difficult to determine due to the number of proposed solutions with relatively little broad comparisons. One type of these models, muscle activation models, describes the nonlinear relationship between neural inputs and mechanical activation of the muscle. Many muscle activation models can be found in the literature, but no comparison is available to guide the community on limitations and improvements. In this research, an EMG-driven elbow motion model is developed for the purpose of evaluating muscle activation models. Seven muscle activation models are used in an optimization procedure to determine which model has the best performance. Root mean square errors in muscle torque estimation range from 1.67–2.19 Nm on average over varying input trajectories. The computational resource demand was also measured during the optimization procedure, as it is an important aspect for determining if a model is feasible for use in a particular wearable assistive device. This study provides insight into the ability of these models to estimate elbow motion and the trade-off between estimation accuracy and computational demand

Datasheet1_Active cooling of twisted coiled actuators via fabric air channels.pdf

Twisted coiled actuators (TCAs) are promising artificial muscles for wearable soft robotic devices due to their biomimetic properties, inherent compliance, and slim profile. These artificial muscles are created by super-coiling nylon thread and are thermally actuated. Unfortunately, their slow natural cooling rate limits their feasibility when used in wearable devices for upper limb rehabilitation. Thus, a novel cooling apparatus for TCAs was specifically designed for implementation in soft robotic devices. The cooling apparatus consists of a flexible fabric channel made from nylon pack cloth. The fabric channel is lightweight and could be sewn onto other garments for assembly into a soft robotic device. The TCA is placed in the channel, and a miniature air pump is used to blow air through it to enable active cooling. The impact of channel size on TCA performance was assessed by testing nine fabric channel sizes—combinations of three widths (6, 8, and 10 mm) and three heights (4, 6, and 8 mm). Overall, the performance of the TCA improved as the channel dimensions increased, with the combination of a 10 mm width and an 8 mm height resulting in the best balance between cooling time, heating time, and stroke. This channel was utilized in a follow-up experiment to determine the impact of the cooling apparatus on TCA performance. In comparison to passive cooling without a channel, the channel and miniature air pump reduced the TCA cooling time by 42% (21.71±1.24 s to 12.54±2.31 s, p<0.001). Unfortunately, there was also a 9% increase in the heating time (3.46±0.71 s to 3.76±0.71 s, p<0.001) and a 28% decrease in the stroke (5.40±0.44 mm to 3.89±0.77 mm, p<0.001). This work demonstrates that fabric cooling channels are a viable option for cooling thermally actuated artificial muscles within a soft wearable device. Future work can continue to improve the channel design by experimenting with other configurations and materials.</p

Design and Fabrication of Embroidered Textile Strain Sensors: An Alternative to Stitch-Based Strain Sensors

Smart textile sensors have been gaining popularity as alternative methods for the continuous monitoring of human motion. Multiple methods of fabrication for these textile sensors have been proposed, but the simpler ones include stitching or embroidering the conductive thread onto an elastic fabric to create a strain sensor. Although multiple studies have demonstrated the efficacy of textile sensors using the stitching technique, there is almost little to no information regarding the fabrication of textile strain sensors using the embroidery method. In this paper, a design guide for the fabrication of an embroidered resistive textile strain sensor is presented. All of the required design steps are explained, as well as the different embroidery design parameters and their optimal values. Finally, three embroidered textile strain sensors were created using these design steps. These sensors are based on the principle of superposition and were fabricated using a stainless-steel conductive thread embroidered onto a polyester&ndash;rubber elastic knit structure. The three sensors demonstrated an average gauge factor of 1.88&plusmn;0.51 over a 26% working range, low hysteresis (8.54&plusmn;2.66%), and good repeatability after being pre-stretched over a certain number of stretching cycles

Design and Fabrication of Embroidered Textile Strain Sensors: An Alternative to Stitch-Based Strain Sensors

Smart textile sensors have been gaining popularity as alternative methods for the continuous monitoring of human motion. Multiple methods of fabrication for these textile sensors have been proposed, but the simpler ones include stitching or embroidering the conductive thread onto an elastic fabric to create a strain sensor. Although multiple studies have demonstrated the efficacy of textile sensors using the stitching technique, there is almost little to no information regarding the fabrication of textile strain sensors using the embroidery method. In this paper, a design guide for the fabrication of an embroidered resistive textile strain sensor is presented. All of the required design steps are explained, as well as the different embroidery design parameters and their optimal values. Finally, three embroidered textile strain sensors were created using these design steps. These sensors are based on the principle of superposition and were fabricated using a stainless-steel conductive thread embroidered onto a polyester–rubber elastic knit structure. The three sensors demonstrated an average gauge factor of 1.88±0.51 over a 26% working range, low hysteresis (8.54±2.66%), and good repeatability after being pre-stretched over a certain number of stretching cycles