Abstrakt Technologie Říjen 2009

“Influence of 2D and 3D view on performance and time estimation in minimal invasive surgery.” Blavier, A. and A. S. Nyssen (2009).

Ergonomics 52(11): 1342-1349.


This study aimed to evaluate the impact of two-dimensional (2D) and three-dimensional (3D) images on time performance and time estimation during a surgical motor task. A total of 60 subjects without any surgical experience (nurses) and 20 expert surgeons performed a fine surgical task with a new laparoscopic technology (da Vinci robotic system). The 80 subjects were divided into two groups, one using 3D view option and the other using 2D view option. We measured time performance and asked subjects to verbally estimate their time performance. Our results showed faster performance in 3D than in 2D view for novice subjects while the performance in 2D and 3D was similar in the expert group. We obtained a significant interaction between time performance and time evaluation: in 2D condition, all subjects accurately estimated their time performance while they overestimated it in the 3D condition. Our results emphasise the role of 3D in improving performance and the contradictory feeling about time evaluation in 2D and 3D. This finding is discussed in regard with the retrospective paradigm and suggests that 2D and 3D images are differently processed and memorised.




“A novel tactile force probe for tissue stiffness classification.”

Darvish, B., S. Najarian, et al. (2009).

American Journal of Applied Sciences 6(3): 512-517.


In this study, we have proposed a new type of tactile sensor that is capable of detecting the stiffness of soft objects. The sensor consists of a brass cylinder with an axial bore. An iron core can easily move inside the bore. Three peripheral bobbins were machined in the cylinder around which three coils have been wound. One of the coils was excited with an alternating current which caused a voltage to be induced in two other coils. A return spring was used to return the core to its initial position after it has been moved. The sensor was pressed against the surface of the object whose stiffness was going to be measured. The position of the core in this state was depended on the stiffness of the given object and the spring constant and was measured by measuring the change in the induced voltage in secondary coils. The proposed sensor was capable of measuring two contact parameters namely the applied force and the stiffness of the object. Using the data of this sensor, three different objects, made of polyurethane, silicon rubber and paraffin gel were discriminated. Thus, this sensor could be used in robot hands and minimally invasive surgery tools to improve their operation. © 2009 Science Publications.




“Robotically Assisted Ablation Produces More Rapid and Greater Signal Attenuation Than Manual Ablation.”

Koa-Wing, M., P. Kojodjojo, et al. (2009).

J Cardiovasc Electrophysiol.


Robotically Assisted Ablation. Introduction: Robotic remote catheter ablation potentially provides improved catheter-tip stability, which should improve the efficiency of radiofrequency energy delivery. Percentage reduction in electrogram peak-to-peak voltage has been used as a measure of effectiveness of ablation. We tested the hypothesis that improved catheter-tip stability of robotic ablation can diminish signals to a greater degree than manual ablation. Methods:In vivo NavX maps of 7 pig atria were constructed. Separate lines of ablation were performed robotically and manually, recording pre- and postablation peak-to-peak voltages at 10, 20, 30, and 60 seconds and calculating signal amplitude reduction. Catheter ablation settings were constant (25W, 50 degrees , 17 mL/min, 20-30 g catheter tip pressure). The pigs were sacrificed and ablation lesions correlated with NavX maps. Results: Robotic ablation reduced signal amplitude to a greater degree than manual ablation (49 +/- 2.6% vs 29 +/- 4.5% signal reduction after 1 minute [P = 0.0002]). The mean energy delivered (223 +/- 184 J vs 231 +/- 190 J, P = 0.42), power (19 +/- 3.5 W vs 19 +/- 4 W, P = 0.84), and duration of ablation (15 +/- 9 seconds vs 15 +/- 9 seconds, P = 0.89) was the same for manual and robotic. The mean peak catheter-tip temperature was higher for robotic (45 +/- 5 degrees C vs 42 +/- 3 degrees C [P < 0.0001]). The incidence of >50% signal reduction was greater for robotic (37%) than manual (21%) ablation (P = 0.0001). Conclusion: Robotically assisted ablation appears to be more effective than manual ablation at signal amplitude reduction, therefore may be expected to produce improved clinical outcomes. (J Cardiovasc Electrophysiol, Vol. pp. 1-7).




“Towards image guided robotic surgery: Multi-arm tracking through hybrid localization.”

Kwartowitz, D. M., M. I. Miga, et al. (2009).

International Journal of Computer Assisted Radiology and Surgery 4(3): 281-286.


Objective: Use of the robotic assisted surgery has been increasing in recent years, due both the continuous increase in the number of applications and the clinical benefits that surgical robots can provide. Currently robotic assisted surgery relies on endoscopic video for navigation, providing only surface visualization, thus limiting subsurface vision. To be able to visualize and identify subsurface information, techniques in image-guidance can be used. As part of designing an image guidance system, all arms of the robot need to be co-localized in a common coordinate system. Methods: In order to track multiple arms in a common coordinate space, intrinsic and extrinsic tracking methods can be used. First, the intrinsic tracking of the daVinci, specifically of the setup joints is analyzed. Because of the inadequacy of the setup joints for co-localization a hybrid tracking method is designed and implemented to mitigate the inaccuracy of the setup joints. Different both optical and magnetic tracking methods are examined for setup joint localization. Results: The hybrid localization method improved the localization accuracy of the setup joints. The inter-arm accuracy in hybrid localization was improved to 3.02 mm. This inter-arm error value was shown to be further reduced when the arms are co-registered, thus reducing common error. © CARS 2009.




“Tool guidance using a compact robotic assistant.”

Nelson, C. A., X. Zhang, et al. (2009).

Journal of Robotic Surgery: 1-3.


Surgical robots in popular clinical use are generally large machines, which limits their practical use to some extent. This study aims to investigate the potential of a small, table-mounted robot for tool guidance in minimally invasive surgery (MIS). In particular, its multipurpose use for guidance of various tools was investigated. A compact robot capable of manipulating MIS tools was designed and built. The robot can move in four degrees of freedom (DOF): three rotational and one translational. These DOF correspond to motion constrained by a trocar. The robot kinematics are based on a bevel-geared “spherical mechanism,” which allows trocar-constrained motion using a small mechanical device. The robot was tested in a porcine model by manipulating scopes and robotic grasping tools using a joystick as directed by a surgeon. Holding a laparoscope, the robot provided superior stability as a camera assistant. It manipulated the scope for visualization of the liver, spleen, bowel, etc. during manual tissue manipulation. Its compactness allowed increased space around the operating table, and the robot was in fact manipulated by joystick from across the room. Maneuvering grasping tools, the robot similarly provided a stable and dexterous platform for tissue manipulation. The test results suggest that the use of robotics for surgery may be enhanced via compact devices to include more hybrid robotic-manual procedures. The robot motion is smoother and more repeatable than that of a human operator. Use of a foot joystick could also place camera control directly with the surgeon. Flexible endoscopes can also be used with the robot for highly dexterous visualization. Notably, changing tools with this system is a very straightforward process and can be achieved without re-registration of the robot’s position/orientation. Therefore, combined with other simple robotic tools for grasping, cautery, etc., compact robotic systems based on this technology could replace the large systems in current use, potentially increasing the impact of robots on medical care. This represents an important step towards multifunctional compact surgical robots. © 2009 Springer-Verlag London Ltd.




“Video Technique for Human Robot-Assisted Microsurgical Vasovasostomy.”

Parekattil, S. J., H. N. Atalah, et al. (2009).

J Endourol.


Abstract Previous studies have shown that robot-assisted microsurgical vasovasostomy (RAVV) has technical advantages over pure microscopic vasovasostomy (MVV) in animal and human models. This study presents a video technique and initial results for RAVV in 20 human cases compared with 7 MVV cases by a single fellowship-trained microsurgeon from July 2007 to June 2009. A three-layer 10-0 and 9-0 suture anastomosis was performed with up to 22 months follow-up (mean 3 months). Mean operative duration for the RAVV cases was 109 and 128 minutes for MVV (p = 0.09). At 2 months postoperatively, all patients were patent. Mean sperm count was 54 million in RAVV and 11 million in MVV (p = 0.04). The use of robotic assistance in microsurgical vasovasostomy may have potential benefit over MVV in decreasing operative duration and significantly improving early semen analysis measures. Further evaluation and longer follow-up is needed to assess its clinical potential.




“Air-cushion force-sensitive probe for soft tissue investigation during minimally invasive surgery.”Zbyszewski, D., B. Challacombe, et al. (2009).

Journal of Endourology 23(9): 1421-1424.


Purpose: We propose a novel air-cushion force-sensitive indentation probe for rapidly locating abnormalities within soft tissues during minimally invasive surgery (MIS). Method: This system comprises a spherical-tipped optical-based force-sensing device that employs an air-cushion technique to conduct continuous rolling indentation over the surface of soft tissues. The device combines rapid acquisition of tissue resistance forces with high manoeuvrability. To determine the stiffness variation, the interaction forces acquired during rolling indentation can be integrated to generate spatio-mechanical stiffness images that can be used for tissue diagnosis. Results: Rolling indentation tests on the probe were carried out on excised porcine liver. The results demonstrate that the probe can be used to acquire force signals for constructing mechanical images, reliably indicating areas of variable stiffness. Conclusions: This probe could be used to characterize the force tissue deflection profile of soft tissues during minimally invasive surgery providing surgeons with enhanced haptic feedback. © Copyright 2009, Mary Ann Liebert, Inc.