Sufficiently accurate thermal modeling is necessary for many applications such as heat dissipation, melting processes, building design or even bio-heat transfers in surgery. Circuit models help modeling heat transfer dynamics: this method is simple and is often used to model thermal phenomena. However, such models well approximates low and high frequency behavior but they are not accurate enough in the middle band of interest, thus lacking of precision in dynamical terms. A more complete and accurate description of conductive heat transfer can be obtained by using a two-port network. The resulting analytical expressions are complex and nonlinear in the frequency ω. This complexity in the frequency domain is difficult to handle when it comes to control applications and more specifically in real-time applications such as surgery. Consequently, an analysis of this thermal two-port network in the frequency domain directly leads to fractional-order systems. A frequency domain analysis of the series and shunt impedances will be presented and different approximations will be explored in order to obtain simple but sufficiently precise linear fractional transfer function models. The series impedances are approximated by using asymptotic and pole-zero approximations and the shunt impedance is approximated by using a capacitance approximation and two fractional model approximations.

Assessment techniques for orthopedics training are primarily subjective, and often based on qualitative metrics. In this paper, we propose an analytical approach for the quantitative assessment of orthopedic surgery training, specifically, bone drilling. Our goal in this paper is to help improve orthopedics training by providing a means to assess the resident training progress. To this end, we introduce a novel metric that assigns a unique signature to an individual’s drilling activity based on their drilling trajectory, and we compare it with the signatures of expert surgeons. We conduct a simple bone-drilling experiment with surgeons (experts) and novice users on a hybrid (physical - digital) setup consisting of 3 D printed bone surrogates that emulate physical and perceptual properties of a human bone across the young and old age groups. We create expert models using our drilling signature metric to evaluate drilling performance for novice users with respect to expert orthopedic surgeons. Our preliminary analysis of drilling signatures across expert and novice users showcases a perceivable distinction across two different bone types highlighting some fundamental insights on the drilling setup, bone material, and user response to each bone type. Our results indicate that the drilling signature helps capture not only a novice user’s drilling behavior, but also their relative expertise as they progress with training.

By surgically incising a patient’s cornea, an ophthalmologist can reduce or eliminate the patient’s myopia (nearsightedness). Although one such keratorefractive procedure, known as radial keratotomy, is a common practice among some ophthalmologists, there is presently no comprehensive or universally accepted method that a surgeon can use to determine how to perform the operation to exactly eliminate a patient’s refractive error. In this paper, a general methodology for designing radial keratotomy procedures that determines the optimal incision geometry on a patient-by-patient basis is presented. This approach is based on coupling a transversely isotropic finite element model of the human cornea to an optical model of the entire eye. Two objective functions are considered, and each one is shown to possess monotonicity properties that specify a constraint bound solution, obtained by directly solving the constraint equations. Consequently, the resulting incision geometry in each formulation not only eliminates the myopic error but yields the global minimum of the objective function.

In this paper, the dynamic response of a piezoelectric transducer in contact with an acoustic media is formulated. This serves as a model problem for an ultrasonic phased array in contact with the human body. These arrays may be used for hyperthermia or ablation surgery; the focus of this paper, however, is the efficient numerical formulation for modeling the array problem. Efficient numerical methods will provide a useful design tool and allow for the investigation of structural–acoustic phenomena. A finite element formulation based on Galerkin and Galerkin Least Squares (GLS) methods is presented. The benefits of the GLS method over the standard Galerkin method are demonstrated through numerical experiments of the dynamic response of a multi–element array. The methods under development can be applied to any fluid structure interaction problem and point strongly to the advantage of GLS methods for mid– and high–frequency applications. The accuracy of approximate versus exact non–reflecting, truncation boundary conditions is discussed.

In the filed of remote manipulation, it is generally required to manipulate objects through elongated tools or through a tele-operation system. In the field of EndoSurgery, one of the challenging tasks for the surgeons is the notion of knotting a suture. This is done by using long graspers and needle drivers which have constrained degrees of freedom caused by the ports of entry to the surgical area. In general, this task is the most time consuming one and requires degree of dexterity which is not available. The objective of this paper is to present an overview of the patented design features of various knotting assisting mechanisms which have been invented for automating aspect of knotting and discussion on a novel and practical design concept. Then this paper presents how the notion of the Knot Theory which is mathematical abstraction can be extended to develop a Graphical Surgeon Interface (GSI) in order to guide the operator during the remote manipulation of the suture during the knotting task and also during the training phases using a haptic interface device.

A new hand held surgical device intended to aid physicians in microsurgery is reported. This device provides a means for delivering small implants through the use of a precision motion linear stepper motor fabricated from silicon and piezoelectric components. The stepper motor described here utilizes the inertial properties of a moving mass as part of the actuation process. Micro Electromechanical Systems-based (MEMS) technology is used in building the device. Test instruments have delivered over fifty implants with consistent performance. Typically the test instruments have attained 1.2 mm/s advancement speeds against 3 Newton resistance loads, a maximum output force of 4.6 Newtons, and maximum total displacement of 38 mm.

This paper presents the preliminary results of a new real-time finite element system which supports haptic (i.e. force) feedback to the user. The methodology of the system is based on linear finite-element analysis. Further, this system was originally developed as part of a real-time skin surgery simulator with the Human Interface Technology Lab and, the Division of Dermatology at the University of Washington Medical School. We are currently exploring its use and development as a new engineering design tool.

The design of an intracorpeal suturing device that will assist surgeons in placing an internal suture through a small incision. Performing surgical procedures through a small incision greatly reduces patient trauma and rehabilitation time, both of which are proportionally related to medical costs. Medical devices exists today that allow surgeons to perform procedures through small incisions, unfortunately, it is difficult to place sutures deep in the body using minimally invasive techniques. A device that enables surgeons to place sutures minimally invasively will facilitate surgeons by increasing the scope of procedures that can be preformed using this technique.

In some applications of compliant mechanisms, the fact that energy is stored in the elastic members presents a problem. For instance, in manually operated instruments, such as surgical forceps, the operating force should preferably be proportional to the gripping force, while forces introduced by the bending of elastic elements would disturb this force transmission process. To restore the force transmission quality, compliant mechanisms may be statically balanced, resulting in statically balanced compliant mechanisms (SBCM’s). This paper presents an example of a compliant surgical forceps mechanism, which is statically balanced by a low-friction rolling-link compensation mechanism. Force feedback is restored to the extent that the pulse in an artificial artery can be perceived clearly.

Laparoscopic surgery is carried out by using an endoscope with a camera that is inserted through a small incision in the abdominal wall. The camera pictures are presented on a monitor. The light source of the endoscope forms a ring around the camera lens, and the endoscope movements are limited by the incision point. The absence of shadows in the camera picture and the restricted ability to observe organs from aside complicate the surgeon’s depth perception. This paper describes the development of a new steerable endoscope that is the product of a close co-operation between the Man-Machine Systems Group of the Delft University of Technology and the Hirose & Yoneda Laboratory of the Tokyo Institute of Technology. The endoscope, which is called Endo-Periscope , uses a new spatial parallelogram-mechanism to transform the movements of the handgrip into movements of the steerable tip. The handgrip contains an arrow that points always in the direction of the line-of-sight of the tip-camera. This provides intuitive control of the tip and it shows the surgeon how the camera is oriented in the abdominal cavity. The light source is located on the shaft and the tip-camera can be moved in six degrees of freedom. This enables the surgeon to observe organs from different sides and to use shadows as a depth information source. Part of the parallelogram-mechanism is a new kind of spring which combines a very high torsional stiffness with a low, asymmetric bending stiffness. The spring and the working principle of the Endo-Periscope have been applied for two patents.

In this paper we describe a surgical navigation system named HipNav (Hip-Navigation) for THR and KneeNav (Knee-Navigation) for TKR with an emphasis on using these systems as a real time intraoperative measurement tool (these enabling technologies are the surgical toolbox of the future). This approach will permit the direct comparison of patient outcomes with measurable surgical techniques.

This paper proposes incorporating compliant mechanisms into the design of minimally invasive surgical tools to help overcome current tool limitations — particularly to increase multifunctionality. To perform multiple unique functions, a compliant mechanism is designed with a single topology that allows multiple input forces to independently produce distinct output displacements. A multicriteria topology optimization procedure is developed for the design of compliant mechanisms, and the procedure is executed using Matlab. This method generates topologies displaying both sufficient compliance and stiffness for each load case by formulating the objective function as a ratio of mutual potential energy to strain energy. The total objective function is then assembled as the weighted sum of the objective functions for each load case. The optimization procedure is illustrated through the generation of topologies for a device based on a grasperscissors combination tool. Also addressed are factors which significantly influence the resulting solution, such as the weighting function value and starting point.

A model has been developed to design a new active, steerable end-effector for minimally invasive surgery. Active material is incorporated into the surgical instrument to increase the degrees of freedom available to the surgeon. This paper focuses on the modeling of the end-effector using both piezoelectric ceramic and electroactive polymer (EAP) materials. The end-effector design consists of a number of bimorph actuator sections in series with each active layer being individually controlled. Each section may behave as either a bimorph or a unimorph actuator, where in the case of unimorph one of the active layers is passive. By varying the strength and direction of the electric field across each section, a prescribed overall shape can be achieved to allow the user to steer the device. The piezoceramic device is modeled using strain energy methods to predict the quasi-static force-deflection behavior. In the EAP model, experimental data for the electrostrictive P(VDF-TrFE) copolymer is used to model the non-linear relationship between the electric field and the induced strain. Due to the large deflections achievable with the EAP, a model for large deflections beams is also used. Modeling is carried out using MATLAB and then the behavior of piezoelectric ceramic is compared to that of electro-active polymer (EAP).

In minimally invasive surgery, surgeons are deprived of direct contact with the patient’s tissue. All manipulation, including diagnostic palpation, is carried out via long and slender instruments, inserted through small trocars inserted in the skin. Due to poor mechanical characteristics, such as internal friction, backlash, and non-linear force transmission functions, current instruments allow only marginal force feedback. Consequently, surgeons lack a major source of vital information, resulting in reduced safety and grasping forces far greater than necessary. Previous research lead to the design of a 10mm-trocar grasper with low friction and an outstanding force transmission characteristic. The present study was conducted to develop this prototype into a clinically applicable instrument which can be used in 5mm-trocar therapy, by redesigning the mechanism while maintaining the excellent mechanical characteristics. This resulted in a clinical prototype, still according the patented rolling link design but in a different embodiment, now also matching the additional specifications. Mechanical testing showed that the mechanical efficiency of the 5mm-trocar version is as high as in the original version. The 5-mm-version will now be used for further optimization and clinical testing.

In some robot applications, workspace limitations can interfere with the desired path. In unstructured environments such as robot assisted surgery, checking for this must be done quickly to minimize procedural delays. Here, an algorithm is proposed that computes the distance between a few points on the desired path and the nearest workspace boundary to determine if the path is admissible (i.e. inside the dextrous workspace). Execution time is dependent on the proximity of the path to the reachable workspace limit and is upper bounded by a configurable workspace deadband value. The algorithm is applied to the ROBODOC ® Surgical Assistant with good results.

Medical robots in neurosurgery are currently used to accurately position a microscope in consonance with MRI images to allow positional awareness relative to important features of surgical focus. Currently, these robots must be “hand” adjusted by the surgeon, unlike the mouth-operated, counterbalanced linkages that are adjusted using a mouth interface. A human interface to the robot will allow smooth operation as well as new programmable motions not obtainable with the non-actuated microscope stands. A robotically guided microscope will be able to move in a spherical motion allowing for quicker and easier focus about a point of interest. Future work in robotic augmentation must certainly allow tools to be manipulated. As a first step, we mount a biopsy holder on a parallel robot and discuss the compliance issues of the entire system.

This paper presents an algorithm for determining the boundary volume of local mesh for haptic rendering. Here haptic rendering is defined as generation of reaction forces and contact shape information for graphical display. Haptic rendering consists of a number of components: a) scene representation b) scene modelling for global collision detection c) collision detection; d) contact profile and e) scene display. As oppose to classical Finite Element Method or Multi-Body Systems dynamics, haptic rendering deals with the modelling of object where the user can interact with them in the virtual environment. This paper concerns with some aspects related to the interaction between the surgeon tool (probe or micro-robot) and a model of human tissue and organ. Specifically the paper addresses analogies between traditional notion of mesh generation used in finite-element analysis and notion of haptic rendering. In fact, when the user interacts with the object, it is not clear which level of accuracy is needed for the creating the sense of reaction forces at the point of interaction. That is the motivation for proposing the notion of ε-mesh in analogy with the similar notion used in the theory of adaptive meshing. The ε-mesh radius is a scalar quantity defined as a function of the material properties of the contacting bodies, the expected local geometry of the bodies, the direction and relative approach velocities of the bodies. Relationships are presented which show how relative coarseness of the ε-mesh radius with respect to the mesh sizes outside of the radius affect the relative reaction forces.

Airway management is one of the most important priorities when dealing with patients with severe injuries, but knowledge of the important anatomy and physiology is needed for providers to perform a successful surgery. This paper provides a solution for the precise cricothyroid membrane detection problem for real-time surgical airway management applications. With a commercial compact and portable cricothyrotomy kit, the proposed method will enable providers with general knowledge to perform successful first-aid airway management. In this paper, we propose a Hybrid Neural Network (HNNet), consisting of two parallel computing ensembles. The first ensemble takes as an input a low-resolution global image and outputs the Region-of-Interest (ROI) from the predefined grids. The high-resolution image is then cropped according to the ROI, and fed into the second ensemble to achieve precise keypoint detection. Global features and their spatial information from the first ensemble are also fed into the second ensemble to improve the precision. A dataset that consists of over 16,000 images from 13 subjects is built, and the location of the cricothyroid membrane in each image is precisely labeled by medical experts. The training results are presented to show both the efficiency and improved performance of our proposed method compared to existing ones.

Single Incision Laparoscopic Surgery (SILS) is a fast-growing method in the field of MIS (Minimally Invasive Surgery) that has the potential to represent the future of laparoscopic surgeries. The major benefits of SILS results from a single incision which makes surgeries essentially scar-less, and it can reduce wound infection substantially as well as recuperation time. Many new researches are now focusing on developing cutting edge technologies to support SILS; however, the practical applications of SILS are constrained by a number of intricacies such as space limitation, absence of dexterous multitasking tools, lack of sufficient actuation force and poor visualization. Deployment and retraction of surgical tools or robots are done manually in the absence of a multitasking tool manipulator which increases the surgery time, risk of injury and surgeon’s fatigue. Our research focuses on designing a novel operative hardware (multitasking manipulator) to facilitate the SILS technique with automatic tool changing capability. A wire driven mechanism has been implemented in the design to minimize the damage to the electronic hardware during sterilization since the electronic actuation and sensing components are located remotely from the end-effector which requires heat or chemical sterilization before surgery. And a wire-driven articulated robotic arm has also been designed to support the manipulator. The details of the robotic design and analysis are conducted in the paper. The feasibility of this robotic method has been demonstrated by experiments.

In this paper, we present the design of a miniaturized actuation system for robotic lumbar discectomy tools. Lumbar dis-cectomy is one of the most common types of back surgery in the United States. Our previous work proposed a new robotic lumbar discectomy (RLD) system consisting of teleoperated articulated instruments inside a robotic cannula for performing this operation. The robotic cannula is used for the independent translation and rotation of the instruments residing in it. Due to the large servo-motor based actuation systems of the initially developed instruments, it was not possible to achieve a fully integrated RLD system. Here, we present the design of a shape memory alloy actuation system for teleoperating RLD tools that allows full integration with the robotic cannula. More than a 10X size reduction in footprint has been achieved. Experimental results show that SMA-driven actuation system meets the instrument range-of-motion, manipulation, and grasping force requirements. Integrated system tests demonstrate the successful operation of the miniaturized RDL tools with the robotic cannula.