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839 OPTICAL PERFORMANCE COMPARISON OF DEFLECTABLE LAPAROSCOPES FOR LAPAROENDOSCOPIC SINGLE-SITE SURGERY

You have accessJournal of UrologyTechnology & Instruments: Laparoscopy: Malignant & Benign Disease1 Apr 2013839 OPTICAL PERFORMANCE COMPARISON OF DEFLECTABLE LAPAROSCOPES FOR LAPAROENDOSCOPIC SINGLE-SITE SURGERY Zachariah Goldsmith, Gaston Astroza, Agnes Wang, W. Neal Simmons, Muhammad Iqbal, Andreas Neisius, Nicholas Kuntz, Ramy Youssef, Michael Lipkin, Glenn Preminger, and Michael Ferrandino Zachariah GoldsmithZachariah Goldsmith DURHAM, NC More articles by this author , Gaston AstrozaGaston Astroza DURHAM, NC More articles by this author , Agnes WangAgnes Wang DURHAM, NC More articles by this author , W. Neal SimmonsW. Neal Simmons DURHAM, NC More articles by this author , Muhammad IqbalMuhammad Iqbal DURHAM, NC More articles by this author , Andreas NeisiusAndreas Neisius DURHAM, NC More articles by this author , Nicholas KuntzNicholas Kuntz DURHAM, NC More articles by this author , Ramy YoussefRamy Youssef DURHAM, NC More articles by this author , Michael LipkinMichael Lipkin DURHAM, NC More articles by this author , Glenn PremingerGlenn Preminger DURHAM, NC More articles by this author , and Michael FerrandinoMichael Ferrandino DURHAM, NC More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2013.02.406AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Flexible working angles and fine optical visualization are major requisite factors in performing laparoendoscopic single-site (LESS) urologic procedures. Multiple mechanical design approaches have been used to develop deflectable laparoscopes for LESS procedures. We compared the optical characteristics of three such devices using a bench top approach to simulate LESS in the straight and deflected positions. METHODS A 10-mm fixed-rod rotating lens device (Storz EndoCameleon) and two 5-mm articulating devices (Olympus EndoEye and Stryker IdealEye) were compared using standard industry testing protocols for image resolution (United States Air Force-1951 test target), distortion (multifrequency grid distortion target), and color reproducibility (Gretag Macbeth color checker). RESULTS The 10-mm fixed-rod rotating lens system demonstrated the highest image resolution (5.04 line pairs/mm), but also the highest distortion (22.8%). Among the 5-mm flexible articulating laparoscopes, resolution was superior with the Olympus EndoEye (4.00 line pairs/mm) compared with the Stryker IdealEye (3.17 line pairs/mm). Distortion (7.0%) and color reproduction (1.18) were superior with the IdealEye vs the EndoEye (18.8 %, 1.27). Laparoscope deflection resulted in attenuation of resolution by 11% with both articulating models, but not with the fixed rod system. CONCLUSIONS Definition of these optical characteristics may inform further development and selection of laparoscopic systems optimized for LESS surgery. A narrow but flexible camera can be crucial in the limited working space available during these procedures. Further investigation is warranted to determine if these objective findings translate into improved surgeon performance. © 2013 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 189Issue 4SApril 2013Page: e344 Advertisement Copyright & Permissions© 2013 by American Urological Association Education and Research, Inc.MetricsAuthor Information Zachariah Goldsmith DURHAM, NC More articles by this author Gaston Astroza DURHAM, NC More articles by this author Agnes Wang DURHAM, NC More articles by this author W. Neal Simmons DURHAM, NC More articles by this author Muhammad Iqbal DURHAM, NC More articles by this author Andreas Neisius DURHAM, NC More articles by this author Nicholas Kuntz DURHAM, NC More articles by this author Ramy Youssef DURHAM, NC More articles by this author Michael Lipkin DURHAM, NC More articles by this author Glenn Preminger DURHAM, NC More articles by this author Michael Ferrandino DURHAM, NC More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Squeezed screw trajectories for smooth regrasping movements of robot fingers

In dextrous robotic manipulation we are often confronted with the problem that the robot fingers need to be repositioned on the object surface, either because a finger reaches its workspace limits or because the manipulation planner decides to do so due to its manipulation strategy. In this paper we propose a trajectory type for the purpose of regrasping, named “Squeezed Screw”. It is smooth and has a relatively simple shape. It is a superposition of a movement on an ellipse with a translation in an arbitrary direction in 3D. It can be generated from only eight input parameters. An algorithm was developed to calculate the path geometry from these parameters. A comparison with a Rapidly-exploring Random Tree algorithm points out the advantages of this novel trajectory type.

Parapharyngeal Space Surgery via a Transoral Approach Using a Robotic Surgical System: Transoral Robotic Surgery

In transoral robotic surgery (TORS), if an endoscopic arm equipped with two integrated cameras is placed close to a lesion, a three-dimensionally magnified view of the operative field can be obtained. More important is that the operation can be performed precisely and bimanually using two instrument arms that can move freely within a limited working space. We performed TORS to treat several diseases that occur in the parapharyngeal space (PPS) and subsequently analyzed the treatment outcomes to confirm the validity of this procedure. Between February 2009 and February 2012, 11 patients who required surgical treatment for the removal of a parapharyngeal lesion were enrolled in this prospective study. Nine patients received TORS for parapharyngeal tumor resection, and 2 patients with stylohyoid syndrome underwent TORS for resection of an elongated styloid process. The average age of the patients included in this study was 42 years. Five patients were male, and 6 patients were female. TORS was successfully performed in all 11 patients. The average robotic system docking and operation times were 9.9 minutes (range, 5-24 minutes) and 54.2 minutes (range, 26-150 minutes), respectively. Patients were able to swallow normally the day after the operation. The average blood loss during the robotic operation was minimal (11.8 mL). The average hospital stay was 2.6 days. There were no significant complications in the perioperative or postoperative period. All patients were extremely satisfied with their cosmetic outcomes. PPS surgery via a transoral approach using a robotic surgical system is technically feasible and secures a better cosmetic outcome than the transcervical, transparotid, or transmandibular approach. This new surgical method is safe and effective for benign diseases of the PPS.

Repair of congenital diaphragmatic hernias through umbilical skin incisions

The use of thoracoscopy and laparoscopy in the treatment of congenital diaphragmatic hernias (CDHs) has been recently reported; however, the use of these procedures still remains controversial due to CO2 insufflation and limited working space. In addition, because of difficult techniques, it has not been widely accepted. Among CDH patients, mild cases whose lung is not hypoplastic, and not associated with persistent pulmonary hypertension of the neonate (PPHN) often develop small defects in the diaphragm that can be repaired using "direct closure." Because direct closure does not require as wide an operative field as that needed for patch closure, we repaired CDH through umbilical skin windows in two neonates with mild CDH to minimize the wounds. With the creation of additional radical small incisions, the surgeries were successfully performed without any intra- or postoperative complications, and the wounds were cosmetically pleasing. The repair of CDHs through umbilical skin windows is a feasible and useful approach in neonates with mild CDH.

Failure to filter: anxious individuals show inefficient gating of threat from working memory

Dispositional anxiety is a well-established risk factor for the development of psychiatric disorders along the internalizing spectrum, including anxiety and depression. Importantly, many of the maladaptive behaviors characteristic of anxiety, such as anticipatory apprehension, occur when threat is absent. This raises the possibility that anxious individuals are less efficient at gating threat's access to working memory, a limited capacity workspace where information is actively retained, manipulated, and used to flexibly guide goal-directed behavior when it is no longer present in the external environment. Using a well-validated neurophysiological index of working memory storage, we demonstrate that threat-related distracters were difficult to filter on average and that this difficulty was exaggerated among anxious individuals. These results indicate that dispositionally anxious individuals allocate excessive working memory storage to threat, even when it is irrelevant to the task at hand. More broadly, these results provide a novel framework for understanding the maladaptive thoughts and actions characteristic of internalizing disorders.

Early Loosening after Total Knee Arthroplasty with Minimal Incision Surgery: A Report of Two Cases and A Review of the Literature

Advances in surgical techniques and equipment have recently encouraged the use of minimal incision surgery (MIS) in total knee arthroplasty (TKA). However several complications have been reported following MIS, among which, early loosening is one of the most serious issues. We report two cases that experienced early loosening of the tibial component within three months of surgery, and received revision surgery within three years of primary MIS TKA. The cases were compared with 50 other cases which received MIS TKAs by the same technique, and it was hypothesized the failures in the two relatively young patients may have been caused by virus implantation of the tibiae component and a large bony cut in the proximal tibia, possibly as a result of limited working space during surgeries.

Co-registration methods for 2D ultrasound and nuclear magnetic resonance images

Event Abstract Back to Event Co-registration methods for 2D ultrasound and nuclear magnetic resonance images Santos R. Yusniel1*, Javier Figueredo2, Joe Michel López Inguanzo1, Marlis Ontivero1, Daylin Gongora1, Jorge Iglesias Fuster1 and Maria Bobes1 1 Cuban Center for Neuroscience (CNEURO), Department of Cognitive Neuroscience, Cuba 2 Center of Medical and Surgical Research (CIMEQ), Cuba Intra-operative MRI and CT images provide information about patient's brain several times during surgery. However, they have serious drawbacks concerning the relatively long image acquisition procedures, high investment and operating costs, a spatially limited workspace and need for special (MR- or CT-compatible) surgical equipment. The optimal solution for neurosurgeons includes a navigation system with high quality images combined with real-time processing and three-dimensional imaging capabilities. Many of these capabilities are available in the ultrasound systems used in neurosurgery for several years. These systems have drawbacks associated with a limited viewing angle, the mixing of study and image data and variable dimensions. However, recent advances has improved the image quality up to a level comparable with intra-operative MRI. Thus, by sorting these limitations, the integration of ultrasound with high resolution MRI represents an efficient and inexpensive procedure for pre-operative surgical planning and intra-operative imaging. Our work combines intra-operative 2D ultrasound images and pre-operative MRI, as well includes fusion with fMRI and DTI images. We present data obtained from surgical procedures in patients with brain tumors. In all cases this procedure allowed the evaluation of 2D ultrasound images combined with MR structural images, fMRI and DTI data, allowing a more efficient surgical planning with successful outcomes. Keywords: brain tumors, ultrasound, neuro-navigation, surgical planning, co-registration Conference: Neuroinformatics 2013, Stockholm, Sweden, 27 Aug - 29 Aug, 2013. Presentation Type: Poster Topic: Neuroimaging Citation: Yusniel SR, Figueredo J, López Inguanzo J, Ontivero M, Gongora D, Iglesias Fuster J and Bobes M (2013). Co-registration methods for 2D ultrasound and nuclear magnetic resonance images. Front. Neuroinform. Conference Abstract: Neuroinformatics 2013. doi: 10.3389/conf.fninf.2013.09.00121 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 23 Jul 2013; Published Online: 23 Jul 2013. * Correspondence: Mr. Santos R Yusniel, Cuban Center for Neuroscience (CNEURO), Department of Cognitive Neuroscience, Havana, Cuba, santos@cneuro.edu.cu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Santos R Yusniel Javier Figueredo Joe Michel López Inguanzo Marlis Ontivero Daylin Gongora Jorge Iglesias Fuster Maria Bobes Google Santos R Yusniel Javier Figueredo Joe Michel López Inguanzo Marlis Ontivero Daylin Gongora Jorge Iglesias Fuster Maria Bobes Google Scholar Santos R Yusniel Javier Figueredo Joe Michel López Inguanzo Marlis Ontivero Daylin Gongora Jorge Iglesias Fuster Maria Bobes PubMed Santos R Yusniel Javier Figueredo Joe Michel López Inguanzo Marlis Ontivero Daylin Gongora Jorge Iglesias Fuster Maria Bobes Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Does Body Habitus of Patients Affect Operative Difficulty During Retroperitoneal Laparoscopic Radical Nephrectomy?

Because of the limited working space available during retroperitoneal laparoscopic radical nephrectomy (LRN), the body habitus of the patient is likely to affect the risk of operative difficulties. This study sought to determine whether anthropometric measurements based on CT and abdominal radiography could be used to predict operative difficulties during retroperitoneal LRN. Between August 2004 and January 2012, 96 consecutive patients with preoperative CT and abdominal radiography examinations underwent retroperitoneal LRN for a T(1) or T(2) stage renal tumor at our institution. The association between anthropometric measurements and demographics of patients and operative duration, estimated blood loss (EBL), and perioperative complications were retrospectively analyzed. Multivariate analysis was performed, and P<0.05 was considered significant. Anterior perirenal fat distance (P=0.016) and distance from the 12th rib to the iliac crest (P=0.038) were independently associated with operative duration. Only anterior perirenal fat distance (P=0.001) was independently associated with EBL. No intraoperative complications and reoperations occurred. The occurrence or severity of postoperative complications was not significantly associated with anthropometric measurements. Body mass index ≥25.0 kg/m(2) was not significantly associated with operative difficulties. The anterior perirenal fat distance and the distance from the 12th rib to the iliac crest can be used to predict operative difficulties during retroperitoneal LRN.

Virtual Robot Kinematic Learning System: A New Teaching Approach

Computer assisted learning systems for robotics can assist students to understand topics on robot modeling, direct and inverse kinematics, join motions, trajectories, and also workspace limitations. This paper presents a virtual robotic kinematic learning system as a new teaching approach of robotics class which will assist and promote better students’ understanding of robotics. From the virtual system’s interface, basic structure and movement of Cartesian, Cylindrical, Spherical and Articulated robot can be visualized. The transformation matrix exercises allow students to write down the formula of translation and rotation matrix and then see the movements of the virtual robot based on the input. In this virtual system, a Lynxmotion Arm Robot was used to teach kinematics for the manipulator movement using Denavit Hartenberg representation. The system is developed using Unity 3D for the animation and for the calculation of robot kinematic, C-Sharp and Java script programming language were used. The system will be evaluated with the students to determine its effectiveness in providing a new teaching approach.

Optical Performance Comparison of Deflectable Laparoscopes for Laparoendoscopic Single-Site Surgery

Flexible working angles and fine optical visualization are major requisite factors in performing laparoendoscopic single-site (LESS) urologic procedures. Multiple mechanical design approaches have been used to develop deflectable laparoscopes for LESS procedures. We compared the optical characteristics of three such devices using a bench top approach to simulate LESS in straight and deflected positions. A 10-mm fixed-rod rotating lens device (Storz EndoCameleon) and two 5-mm articulating devices (Olympus EndoEye and Stryker IdealEye) were compared using standard industry testing protocols for image resolution (United States Air Force-1951 test target), distortion (multifrequency grid distortion target), and color reproducibility (Gretag Macbeth color checker). The 10-mm fixed-rod rotating lens system demonstrated the highest image resolution (5.04 line pairs/mm), but also the highest distortion (22.8%). Among the 5-mm flexible articulating laparoscopes, resolution was superior with the Olympus EndoEye (4.00 line pairs/mm) compared with the Stryker IdealEye (3.17 line pairs/mm). Distortion (7.0%) and color reproduction (1.18) were superior with the IdealEye vs the EndoEye (18.8 %, 1.27). Laparoscope deflection resulted in attenuation of resolution by 11% with both articulating models, but not with the fixed rod system. Definition of these optical characteristics may inform further development and selection of laparoscopic systems optimized for LESS surgery. A narrow but flexible camera can be crucial in the limited working space available during these procedures. Further investigation is warranted to determine if these objective findings translate into improved surgeon performance.

Transumbilical 1-port laparoscopic resection of benign ovarian tumor

Background/PurposeWe evaluated the effectiveness of transumbilical 1-port laparoscopic resection of benign ovarian tumors in children with limited working space. MethodsThis study involved 15 children and adolescents with benign ovarian tumors treated from January 2006 to December 2010. Preoperative evaluation included physical findings, tumor markers, and imaging studies. A single surgeon performed the procedure using a 10-mm 0° operative laparoscope with a 5-mm working channel. The fallopian tube was suspended with transabdominal suspensory sutures passing through the mesosalpinx to expose the tumor and remove it after aspiration of the contents. The tumor was contained in the endobag and chopped into pieces before removal through the small umbilical wound. ResultsThe patients' age ranged from 2 to 17 years (mean, 9.7 years). Tumor size ranged from 3.6 to 23 cm. Tumor markers including α-fetoprotein, β-human chorionic gonadotropin, cancer antigen 125, and carcinoembryonic antigen were negative. The average operating time was 134 minutes. Except for 1 patient with associated encephalomyelitis, all patients were discharged within 3 days after surgery. Pathologic examination and follow-up studies revealed benign tumors, with no residual lesions in the abdomen or recurrence. ConclusionsTransumbilical 1-port laparoscopic resection is effective for resection of benign ovarian tumors in children, with a satisfactory cosmetic outcome. However, to prevent inadequate resection of a potential malignant lesion, thorough preoperative evaluation with physical signs, tumor markers, and imaging studies, as well as flexible intraoperative tactics, should be adopted.

A novel multifunctional rotary actuator with magnetorheological fluid

In some environments with very limited working space, an integrated actuation device with multiple functions would be desirable. This paper is aimed at developing a novel magnetorheological (MR) fluid based multifunctional rotary actuator. To decrease the dimension of the actuation device while enhancing the functionality, a motor part and MR fluid are integrated into one device. With MR fluid, the actuator possesses multiple functions as motor, clutch, and brake. In this paper, the configurations and design details of the motor part and clutch/brake part are illustrated, and the operating principle of the actuator is discussed as well. The torques of the motor part and clutch/brake part are derived. The finite element method is utilized to analyze the magnetic circuits, the influence of permanent magnets on the MR fluid, and the magnetic flux distribution. A prototype of the actuator is fabricated and each function is tested. The results show that the developed actuator is promising for applications which require multiple functions with compact size.

V2158 ROBOTIC SINGLE SITE KIDNEY SURGERY: EARLY EXPERIENCE IN A CADAVER MODEL WITH NOVEL PURPOSE-BUILT INSTRUMENTS

You have accessJournal of UrologySingle Port Surgery1 Apr 2012V2158 ROBOTIC SINGLE SITE KIDNEY SURGERY: EARLY EXPERIENCE IN A CADAVER MODEL WITH NOVEL PURPOSE-BUILT INSTRUMENTS Riccardo Autorino, Humberto K. Laydner, Shahab Hillyer, Rachid Yakoubi, Ahmad Kassab, Wahib Isaac, Emad Rizkala, Georges-Pascal Haber, Robert J. Stein, and Jihad H. Kaouk Riccardo AutorinoRiccardo Autorino Cleveland, OH More articles by this author , Humberto K. LaydnerHumberto K. Laydner Cleveland, OH More articles by this author , Shahab HillyerShahab Hillyer Cleveland, OH More articles by this author , Rachid YakoubiRachid Yakoubi Cleveland, OH More articles by this author , Ahmad KassabAhmad Kassab Cleveland, OH More articles by this author , Wahib IsaacWahib Isaac Cleveland, OH More articles by this author , Emad RizkalaEmad Rizkala Cleveland, OH More articles by this author , Georges-Pascal HaberGeorges-Pascal Haber Cleveland, OH More articles by this author , Robert J. SteinRobert J. Stein Cleveland, OH More articles by this author , and Jihad H. KaoukJihad H. Kaouk Cleveland, OH More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2012.02.2330AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES A novel set of robotic instruments - termed the da Vinci Single-Site instruments - has been developed specifically for robot assisted single-site laparoscopy. We first described their use in a porcine model. More recently, clinical cholecystectomy series have been reported. Herein, we describe a second generation of instruments for robotic single-site surgery and report our early experience in a cadaver model for kidney procedures. METHODS Three types of kidney procedures (ie pyeloplasty, partial nephrectomy & nephrectomy) were performed in a female cadaver using a da Vinci Si™ system in a 3-arm configuration and a set of novel instruments specifically designed for urologic and gynecologic procedures. The sets includes: a multichannel port allowing the placement of an 8.5-mm scope, a 12-mm assistant port, and 2 crossing curved cannulae for the robotic instruments. These cannualae are shorter than the already described version as they are specifically designed for urologic and gynecologic single site surgery. Instruments feature a semirigid shaft allowing them to be inserted through the cannulae, but they do not have a wrist at the distal tip. The multichannel port was inserted through a 2.5 cm transumbilical incision. A lower abdominal standard port was also inserted but only used for video recording purposes RESULTS Time to setup was 40 minutes. No significant gas leak was observed. Three left side procedures successfully completed without addition of extra ports in 4 hours. Suturing time for pyeloplasty was 39 min. Ischemia time for partial nephrectomy was 21 min. Lack of wrist at instrument tip affected suturing tasks and previous laparoscopic experience is needed. Limited range of motion was noted by the console surgeon at the edges. Instrument exchange was easy. Suboptimal retraction and suction by the assistant was due to collision/unfavorable working angle and limited external working space. CONCLUSIONS The feasibility of a variety of robotic kidney procedures by using a 2nd generation of instruments specifically designed for da Vinci™ single-site surgery has been demonstrated in a cadaver model. Advantages of this system compared with conventional LESS include increased dexterity, instrument and scope stability, better ergonomics, and decreased instrument clashing. Limitations have been observed, including lack of articulated instruments and difficulty for the bedside assistant due to limited working space © 2012 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 187Issue 4SApril 2012Page: e871 Advertisement Copyright & Permissions© 2012 by American Urological Association Education and Research, Inc.MetricsAuthor Information Riccardo Autorino Cleveland, OH More articles by this author Humberto K. Laydner Cleveland, OH More articles by this author Shahab Hillyer Cleveland, OH More articles by this author Rachid Yakoubi Cleveland, OH More articles by this author Ahmad Kassab Cleveland, OH More articles by this author Wahib Isaac Cleveland, OH More articles by this author Emad Rizkala Cleveland, OH More articles by this author Georges-Pascal Haber Cleveland, OH More articles by this author Robert J. Stein Cleveland, OH More articles by this author Jihad H. Kaouk Cleveland, OH More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Nonlinear Mechanical Analysis of Polymer Precast Panel for Temporary Support of Tunnels

The increase of population in developed cities has improved the requirement for new advanced transportation method such as urban railway system. Therefore, the needs of developing advanced technology in the tunnelling construction for the use of underground railway system are necessary. Underground railways are one of the most accepted systems used for transporting a large amount of people in highly populated cities, which its development requires a set of advanced science such as in the tunnelling construction process. One of the significant failure may occur in tunnels is ceiling collapse. This failure is a major concern during construction to avoid hazardous for workers. In the past few decades, the combination of sprayed concrete and steel meshes (shotcrete) are utilised as temporary support for tunnels during the construction process. This was a time consuming procedure and for a team of workers, they face plenty of obstacles from safety concern to limited working space area when mounting some heavy panel inside the tunnels. To overcome these problems, an experimental test was carried out using Hard Density Polyethylene (HDPE) which is approximately has the same stiffness to shotcrete but 50% less of the weight of the structure. A rectangular beam sample of was manufactured as a precast panel and experimentally tested under three-point bending load as in the real conditions. Maximum deflection and total reaction force of the panels was recorded. The nonlinear mechanical behaviour of the specimen is analysed based on the bending stiffness. Considering the hyper-elastic behaviour of HDPE, the overall response of the sample had shown a good acceptable strength 14.3% higher than the desired strength which can approve the right material selection. In addition, discussion was given on total stiffness and reduced stiffness because of nonlinear behaviour of the HDPE. The value of strain is measured at the bottom surface of the HDPE beam along the length and width the sample for further discussion. This type of polymer can be assumed as large strain material and it is showing a large deformation under three-point bending condition which can help to inform workers about the safety of the whole structure.

Active Handrest: A large workspace tool for precision manipulation

To address the limited dexterous workspace of the human hand, we have developed the Active Handrest. This device assists in precision manipulation tasks by extending a user’s dexterous workspace while providing ergonomic support for reduced fatigue. People use handrests to complete dexterous activities as routine as providing a signature. However, the dexterous workspace of the statically supported hand is somewhat limited. By providing consistent support over large workspaces the Active Handrest could be useful for performing precision tasks, such as surgery, upper limb rehabilitation, and machining. Our prototype Active Handrest is a planar, human–machine interface that provides support for the user’s wrist and arm while allowing the user to retain complete control over a grasped tool or manipulated device. The Active Handrest uses force input from the user’s hand, position input from a grasped tool, or a combination of these inputs. The device’s controller then converts the input(s) into handrest motions. In this paper we describe our novel device prototype and establish a baseline for its performance. Preliminary experiments were conducted to investigate the effects of control input, velocity limits, and user experience. Subsequent experiments compared the Active Handrest to various other support conditions. Use of the Active Handrest was found to significantly reduce task error and provided better speed-accuracy performance than the other tested support methods.

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Laparoscopic totally extraperitoneal (TEP) repair has been accepted as a popular procedure for inguinal hernia repair, but surgeons still encounter technical difficulties owing to unfamiliar pelvic anatomy and limited working space. We sought to estimate the learning curve for laparoscopic TEP repair without supervision. We retrospectively analyzed the medical records of patients scheduled for laparoscopic TEP repair of an inguinal hernia from December 2000 to October 2007. We reviewed medical records for 700 patients. The cases were divided into 8 groups: 20 patients each in groups I-V and 200 patients each in groups VI-VIII. No significant difference in demographic characteristics was identified among the groups. The mean duration of surgery significantly decreased (p < 0.001) in relation to experience; it reached a plateau of less than 30 minutes (mean 28 min) after 60 cases. The mean length of stay in hospital was 0.97 days, reaching a plateau after 20 cases. Six patients were converted to other techniques: 1 patient each in groups III and VIII and 4 patients in group VII. Three recurrences were detected; however, 2 were excluded because the patient had bilateral inguinal hernias. We estimate the learning curve for laparoscopic TEP repair is 60 cases for a beginner surgeon. The presence of an experienced supervisor during the first 60 cases can help prevent unnecessary complications and shorten the duration of surgery.

Kinematics and Workspace Analyses of 3/3-RRRS Parallel Manipulator

It is known that two primary disadvantages of parallel manipulators are the complicated forward kinematics and limited workspace. This paper mainly addressed the kinematics and workspace analyses of a 3/3-RRRS 6-DOF parallel manipulator. After a brief introduction of the 3/3 -RRRS 6-DOF parallel manipulator, a three-dimensional model and its relevant structure diagram are constituted, the forward and inverse displacement analyses of the 3/3-RRRS parallel manipulator are discussed in detail, especially, a novel geometrical method referred as equivalent mechanism is proposed for the forward displacement analysis of the manipulator under consideration. Based on the displacement analyses of the manipulator, a discretization method is proposed for the computation of the reachable position/orientation workspace of the 3/3-RRRS parallel manipulator, respectively. Examples of a 3/3-RRRS parallel manipulator are given to demonstrate these theoretical results.

The evolving role of simulators and training in robotic urological surgery: Which assessment tool to use?

The evolving role of simulators and training in robotic urological surgery: Which assessment tool to use?

A Case of Giant Ovarian Cyst Managed Successfully Through Laparoscopic Surgery

Mucinous ovarian tumors account for 15% all ovarian neoplasms, of which giant variants rarely occur. Recently huge ovarian cysts (more than 12 kg) are now rarely seen because of the development in health care systems and education. The patient is 26-yearold nulligravida female who presented with abdominal distension. A laparoscopic left salpingo-oophorectomy was performed. Laparoscopic approach to giant ovarian cyst may be difficult regarding the risk of cyst rupture and limited working space. To reduce the limitations of the laparoscopy, we performed laparoscopy after aspirating the cystic contents. During laparoscopy, abdominal cavity was explored by the scope. Cyst contained about 53 L of fluid. The histopathologic examination revealed a borderline mucinous tumor of the left ovary. Laparoscopic excision of giant ovarian cyst seems to be safe and applicable treatment modality.

A new approach to determine the maximal singularity-free zone of 3-RPR planar parallel manipulator

SUMMARYThis paper presents a new algorithm to find the singularity-free cylindrical workspace of parallel manipulators. Because of the limited workspace of parallel manipulators cluttered with different types of singularities, a simple and robust technique to determine continuous singularity-free zones in the workspace of parallel manipulators is required. Here, the largest singularity-free cylinder within the workspace for any prescribed orientation ranging around a reference orientation angle of moving platform is determined. To this end, Particle Swarm Optimization is utilized to find the closest point on the singularity surface to the axis of the cylinder. By implementing the algorithm on 3-RPR planar parallel manipulator, the results show that this algorithm improves the efficiency and leads to significantly larger singularity-free workspace than those reported earlier.