M. Cenk Cavusoglu

Robotics for telesurgery: second generation Berkeley/UCSF laparoscopic telesurgical workstation and looking towards the future applications

Robotic telesurgery is a promising application of robotics to medicine, aiming to enhance the dexterity and sensation of regular and minimally invasive surgery through using millimeter‐scale robotic manipulators under the control of the surgeon. In this paper, the telesurgical system will be introduced with discussion of kinematic and control issues and presentation of in vitro experimental evaluation results.

In touch with robotics: neurosurgery for the future.

THE INTRODUCTION OF multiple front-end technologies during the past quarter century has generated an emerging futurism for the discipline of neurological surgery. Driven primarily by synergistic developments in science and engineering, neurosurgery has always managed to harness the potential of the latest technical developments. Robotics represents one such technology. Progress in development of this technology has resulted in new uses for robotic devices in our discipline, which are accompanied by new potential dangers and inherent risks. The recent surge in robot-assisted interventions in other disciplines suggests that this technology may be considered one of a spectrum of frontier technologies poised to fuel the development of neurosurgery and consolidate the era of minimalism. On a more practical level, if the introduction of robotics in neurosurgery proves beneficial, neurosurgeons will need to become facile with this technology and learn to harness its potential so that the best surgical results may be achieved in the least invasive manner. This article reviews the role of robotic technology in the context of neurosurgery.

Virtual environments for training critical skills in laparoscopic surgery.

Surgical training simulations must incorporate not only advanced technical features, such as detailed geometric organ models and physically-based modeling techniques, but also a thorough understanding of the major training issues relating to a particular procedure. We have developed a prototype environment for training laparoscopic cholecystectomy, or gallbladder removal surgery, which focuses a students attention on the critical steps performed during the procedure and provides feedback as to the common errors committed during a session. The current version of our system runs in real-time on a mid-range graphics workstation. The simulation also provides a platform for research into a variety of different areas, including tissue modeling, finite element methods, and generalized simulation authoring.

Design of a Parallel Robot for Needle-Based Interventions on Small Animals

In this paper, a novel 5-degrees-of-freedom robot for performing needle-based interventions on small animal subjects is presented. The robot can realize dexterous alignment of the needle using two parallel mechanisms, and has a syringe mechanism to insert needles to subjects. Operations on small animals require high accuracy positioning during needle insertion. The kinematic calibration procedure of the robot using an optical tracker as an external sensor is presented to enhance accuracy of the system. After the kinematic calibration, the positioning accuracy of the needle tip is measured as 0.4 mm RMS. The robot design is light weight, and has a motion bandwidth of 4 Hz. The robot can track reference trajectories with a closed-loop controller.

Virtual reality simulation: basic concepts and use in endoscopic neurosurgery training.

IntroductionVirtual reality simulation is a promising alternative to training surgical residents outside the operating room. It is also a useful aide to anatomic study, residency training, surgical rehearsal, credentialing, and recertification.DiscussionSurgical simulation is based on a virtual reality with varying degrees of immersion and realism. Simulators provide a no-risk environment for harmless and repeatable practice. Virtual reality has three main components of simulation: graphics/volume rendering, model behavior/tissue deformation, and haptic feedback. The challenge of accurately simulating the forces and tactile sensations experienced in neurosurgery limits the sophistication of a virtual simulator. The limited haptic feedback available in minimally invasive neurosurgery makes it a favorable subject for simulation.ConclusionsVirtual simulators with realistic graphics and force feedback have been developed for ventriculostomy, intraventricular surgery, and transsphenoidal pituitary surgery, thus allowing preoperative study of the individual anatomy and increasing the safety of the procedure. The authors also present experiences with their own virtual simulation of endoscopic third ventriculostomy.

Determination of elasticity parameters in lumped element (mass-spring) models of deformable objects

Lumped element models, also known as, mass-spring-damper models, are widely used to simulate deformable objects because of their simplicity and computational efficiency. However, the parameters of lumped element models are typically determined in an ad hoc fashion through trial-and-error, as these models are not directly based on continuum mechanics of deformable objects. In this paper, an alternative method to determine the elasticity parameters of lumped element models of deformable objects is presented. The elasticity parameters are determined using an optimization that minimizes the matrix norm of the error between the stiffness matrices of the linear lumped element model and the linear finite element model of the same object. The method has been developed for two-dimensions and for three-dimensional volumetric objects with tetrahedral and hexahedral (brick) elements. The method has been validated by comparing deformation results of the lumped element models with the deformation results given by finite element models, under various tension, and compression loading conditions.

Personal navigation via shoe mounted inertial measurement units

We are developing a personal micronavigation system that uses high-resolution gait-corrected inertial measurement units. The goal of this project is to develop a navigation system that use secondary inertial variables, such as velocity, to enable long-term precise navigation in the absence of Global Positioning System (GPS) and beacon signals. In this scheme, measured zero velocity durations from the ground reaction sensors are used to reset the accumulated integration errors from the accelerometers and gyroscopes in position calculation. We achieved an average position error of 4 meters at the end of half-hour walks.

Needle path planning for autonomous robotic surgical suturing

This paper develops a path plan for suture needles used with solid tissue volumes in endoscopic surgery. The path trajectory is based on the best practices that are used by surgeons. The path attempts to minimize the interaction forces between the tissue and the needle. Using surgical guides as a basis, two different techniques for driving a suture needle are developed. The two techniques are compared in hardware experiments by robotically driving the suture needle using both of the motion plans.

Three dimensional modeling of an MRI actuated steerable catheter system

This paper presents the three dimensional kinematic modeling of a novel steerable robotic ablation catheter system. The catheter, embedded with a set of current-carrying micro-coils, is actuated by the magnetic forces generated by the magnetic field of the MRI scanner. This paper develops a 3D model of the MRI actuated steerable catheter system by using finite differences approach. For each finite segment, a quasi-static torque-deflection equilibrium equation is calculated using beam theory. By using the deflection displacements and torsion angles, the kinematic modeling of the catheter system is derived. The proposed models are evaluated by comparing the simulation results of the proposed model with the experimental results of a proof-of-concept prototype.

Modeling of needle-tissue interaction forces during surgical suturing

This paper presents a model of needle tissue interaction forces that a rigid suture needle experiences during surgical suturing. The needle-tissue interaction forces are modeled as the sum of lumped parameters. The model has three main components; friction, tissue compression, and cutting forces. The tissue compression force uses the area that the needle sweeps out during a suture to estimate both the force magnitude and force direction. The area that the needle sweeps out is a direct result of driving the needle in a way that does not follow the natural curve of the needle. The friction force is approximated as a static friction force along the shaft of the needle. The cutting force acts only on the needle tip. The resulting force and torque model is experimentally validated using a tissue phantom. These results indicate that the proposed lumped parameter model is capable of accurately modeling the forces experienced during a suture.