Showing papers in "International Journal of Medical Robotics and Computer Assisted Surgery in 2009"

OpenIGTLink: an open network protocol for image-guided therapy environment

Abstract: Background With increasing research on system integration for imageguided therapy (IGT), there has been a strong demand for standardized communication among devices and software to share data such as target positions, images and device status.

Steerable catheters in minimally invasive vascular surgery.

Abstract: Background Remote-controlled catheter navigation systems have recently been introduced into minimally invasive vascular surgery and some of them have already been applied in clinical practice. Steerable catheters with improved manoeuvrability play an important role in these innovations for conventional catheterization. Methods This review details the development of various steerable catheters, both in use clinically and under investigation. Comprehensive comparison and analysis in several key aspects are followed to reveal both the advantages and limitations of these catheters, as well as the requirements for relevant techniques. Results Steerable catheters are able to select direction in the distal end, and superior to conventional counterparts in many aspects. Differences between magnetic and active catheters mainly lie in function, safety, configuration of operating room and cost. They have similar requirements for miniaturization and slave insertion mechanisms. Conclusions Steerable catheters are rapidly evolving and still require technological refinements to extend current capabilities. Copyright © 2009 John Wiley & Sons, Ltd.

Robotic-assisted single-incision right colectomy: early experience

Abstract: Background Application of laparoendoscopic single-site surgery (LESS) is increasing across surgical disciplines. In addition to the possibility of decreased postoperative pain, LESS offers better cosmesis with virtually ‘scarless’ surgeries, while avoiding the increased costs and complexity of natural orifice surgery. Instrument conflict minimization often requires the crossing of articulating instruments, which we believe can be more intuitively facilitated using the daVinci-S® robotic system. We describe our early experience with three robotic single-incision right hemicolectomies. Methods Three robotic single-incision right hemicolectomies were performed using the daVinci-S robotic system, utilizing a single 4 cm incision through or around the umbilicus. The procedure was performed using three robotic arms, a 12 mm camera and two 8 mm robotic ports. A medial to lateral approach was used and an extracorporeal resection and anastomosis was performed after undocking the robot. Results There were no intraoperative or postoperative complications. Average operative time was 152 min. The first case was converted to non-robotic single-incision right hemicolectomy during mobilization of the ascending colon, due to uncontrollable air leakage around the ports. The second and third cases were successfully completed without air loss by purse-stringing sutures around each individual port and the use of the SILS™ port, respectively. Conclusions Robotic-assisted single-incision right hemicolectomy can be successfully and safely performed using the daVinci-S robotic system. Several techniques may be employed to prevent the loss of pneumoperitoneum. We believe right hemicolectomy lends itself to single-site surgery because specimen extraction requires a 4 cm incision and may confer patient benefit, with decreased postoperative pain and improved cosmesis. By crossing the robotic instruments and reassigning control of the arms, the robot represents a means to help perform these procedures safely by allowing them to be performed in a more intuitive fashion. Copyright © 2009 John Wiley & Sons, Ltd.

A novel computer-assisted drill guide template for lumbar pedicle screw placement: a cadaveric and clinical study

Abstract: Background The great accuracy of computer-assisted operative systems for pedicle screw insertion makes them highly desirable for spinal surgeries. However, computer-assisted pedicle screw placement is expensive, and the learning curve for these techniques is significant. We have developed a novel method of spinal pedicle stereotaxy by reverse engineering (RE) and rapid prototyping (RP) and have validated the method's accuracy by cadaveric and clinical study. Methods A volumetric CT scan was performed on each desired lumbar vertebra and a three-dimensional (3D) reconstruction model was generated with MIMICS 10.1, while the optimal screw size and orientation were determined using UG Imageware 12.1. A drill template was created using UG Imageware 12.1, with a surface that is the inverse of the vertebral surface. The drill template and its corresponding vertebra were manufactured using RP. The method was tested on six cadavers without any fluoroscopic control at surgery. Eventually, the technology was applied in six clinical cases. Results The accuracy of the drill template was confirmed by preoperatively drilling the screw trajectory into the vertebra biomodel. In the cadaveric experiment, 36 pedicle screws were inserted and no pedicle perforation was observed by postoperative CT scan. In the six clinical patients, the best fit for positioning the template was easily found manually during the operation. The required time between fixation of the template to the lamina and insertion of the pedicle screw into each segment (one or two vertebrae) was 1–2 min. In total, 22 screws were inserted into T12-L5, with two to four screws/patient. No misplacement occurred using the individual templates. Fluoroscopy was used only once after all the pedicle screws had been inserted. The method significantly reduces operation time and radiation exposure for the members of the surgical team. Conclusions The authors have developed a novel computer-assisted drill template for lumbar pedicle screw placement. This method has shown its ability to customize the placement and size of each screw, based on the unique morphology of the lumbar vertebra. The potential use of drill templates to place lumbar pedicle screws is promising. Copyright © 2009 John Wiley & Sons, Ltd.

Computer-assisted therapy in orbital and mid-facial reconstructions

Abstract: Background: Management of orbital and mid-facial fractures requires a thorough ophthalmic evaluation and precise imaging. A principle goal of therapy is to anatomically reduce fracture segments and to restore a normal orbital volume as soon as possible. Diagnostic advances such as new surgical and imaging techniques have dramatically improved both the functional and aesthetic outcome of reconstructions. Methods: Orbital reconstruction is performed using computer-assisted navigation. This technique makes preoperative simulation by mirroring the unaffected side onto the affected side. Results: Results from computer-assisted navigation application to both primary and secondary orbital and mid-facial reconstruction are shown. Conclusion: Navigation technique it offers significant advantages in both primary and secondary reconstructions. Navigation facilitates reconstruction in unilateral defects through mirroring techniques, and in bilateral defects by importing virtual models from standard CT datasets improving the software tool to fulfil the need for maxillofacial surgery reconstruction. Copyright © 2009 John Wiley & Sons, Ltd.

Using the PhysX engine for physics‐based virtual surgery with force feedback

Abstract: Background The development of modern surgical simulators is highly challenging as they must support complex simulation environments. The demand for higher realism in such simulators has driven researchers to adopt physics-based models which are computationally very demanding. This poses a major problem since real time interactions must permit graphical updates of 30 Hz and a much higher rate of 1 kHz for force feedback (haptics). Recently several physics engines have been developed which offer multi-physics simulation capabilities including rigid and deformable bodies, cloth and fluids. While such physics engines provide unique opportunities for the development of surgical simulators, their higher latencies, compared to what is necessary for real time graphics and haptics, offer significant barriers to their use in interactive simulation environments.

Accuracy analysis of three-dimensional bone surface models of the forearm constructed from multidetector computed tomography data.

Abstract: Background We developed an original computer program that simulates upper limb reconstruction surgery using three-dimensional (3D) bone models constructed from computed tomography (CT) data. However, the accuracy of a bone model has not been clarified, and radiation exposure from CT scanning posed a concern. The purpose of this study was to investigate the appropriate CT parameters required to reduce radiation exposure while maintaining the accuracy of 3D models of the forearm bones. Methods Twelve dry forearm bones were used to investigate the accuracy of 3D bone models created from two different CT parameters. The accuracy was evaluated by measuring: (a) the discrepancy between the models constructed from low- and normal-dose CT parameters; (b) the error between actual surface data derived by a contact-type coordinate measuring machine and a 3D bone model; and (c) the difference between a 3D bone model constructed from a bare dry bone and a model constructed from the same bone embedded in a radio-opaque soft tissue substitute. CT dose index (CTDI) and dose-length product (DLP) were recorded to evaluate the radiation exposure. Results The mean error between bone models constructed from two different CT parameters was 0.04 mm. CTDI and DLP for the normal-radiation dose condition were 9.3 and 563 mGy/cm and those for the low-radiation dose condition were 0.3 and 18 mGy/cm, respectively. The mean error between the bone models and scanning data from contact measurement was 0.45 mm. The mean error between a 3D model constructed from a dry bone and that constructed from the same bone embedded in a radio-opaque soft tissue substitute was 0.06 mm. Conclusions 3D bone models constructed from low-radiation dose CT data demonstrated the same level of accuracy as those constructed from normal-radiation dose data. The present simulation system can produce 3D bone models with one-thirtieth of the normal radiation dose in the forearm. Copyright © 2009 John Wiley & Sons, Ltd.

Cone-beam computed tomography of the maxillofacial region--an update.

Abstract: Background During the last few years, craniomaxillofacial diagnosis of the head has been confronted with an increasing number of innovations and improvements. The main progress occurred following the introduction of cone-beam technology in computed tomography in the 1990s. The number of manufacturers and devices using this technology for the maxillofacial region is growing rapidly and they are now becoming readily available. Materials This article focuses on cone-beam computed tomography (CBCT) devices applied to the maxillofacial region. CBCT serves as a bridge from two dimensions (2D) to three dimensions (3D), with lower irradiation than conventional CT. Different manufacturers and models are now available to satisfy the different needs of clinicians. Results A recent review of the manufacturers found 23 CBCT devices on the market. The specifications, applications and other issues of currently available CBCT devices are presented and discussed. Conclusions 3D imaging is developing at a very fast pace. New technologies and machines are emerging and CBCT is becoming readily available. Due to the growing demand for the technology based on the needs of clinicians, there is now a wide and growing selection of devices on the market. Some of the new advances now mean that CBCT imaging should be a well-considered option in maxillofacial imaging. Copyright © 2009 John Wiley & Sons, Ltd.

Trauma Pod: a semi-automated telerobotic surgical system.

Abstract: Background The Trauma Pod (TP) vision is to develop a rapidly deployable robotic system to perform critical acute stabilization and/or surgical procedures, autonomously or in a teleoperative mode, on wounded soldiers in the battlefield who might otherwise die before treatment in a combat hospital could be provided. Methods In the first phase of a project pursuing this vision, a robotic TP system was developed and its capability demonstrated by performing selected surgical procedures on a patient phantom. Results The system demonstrates the feasibility of performing acute stabilization procedures with the patient being the only human in the surgical cell. The teleoperated surgical robot is supported by autonomous robotic arms and subsystems that carry out scrub-nurse and circulating-nurse functions. Tool change and supply delivery are performed automatically and at least as fast as performed manually by nurses. Tracking and counting of the supplies is performed automatically. The TP system also includes a tomographic X-ray facility for patient diagnosis and two-dimensional (2D) fluoroscopic data to support interventions. The vast amount of clinical protocols generated in the TP system are recorded automatically. Conclusions Automation and teleoperation capabilities form the basis for a more comprehensive acute diagnostic and management platform that will provide life-saving care in environments where surgical personnel are not present. Copyright © 2009 John Wiley & Sons, Ltd.

Image-guided navigation: the surgeon's perspective on performance consequences and human factors issues

Abstract: Background Image-guided navigation (IGN) represents a first step in the automation of surgical functions The use of IGN can involve several human factors issues that must be taken into account when evaluating their impact on surgical performance and patient safety Methods A nationwide survey was conducted among 213 surgeons from 112 German hospitals in order to assess the perceived performance consequences and human factors issues of IGN, including changes of situation awareness, performance and workload, as well as issues of overreliance, skill degradation and usability Results Generally, surgeons report improved performance and patient safety related to the use of IGN However, issues of increased time pressure and mental demands were reported by inexperienced users Furthermore, overreliance on IGN represents a risk, albeit only in a minority of respondents Conclusions IGN is evaluated as a helpful tool for surgeons However, special care should be taken to provide surgeons with sufficient time and training during familiarization with an IGN system Copyright © 2009 John Wiley & Sons, Ltd

The impact of robotics on practice management of endometrial cancer: transitioning from traditional surgery

Abstract: Background Evaluation of the impact of a new robotic surgery programme on perioperative outcomes for endometrial cancer Methods A prospective database of all patients undergoing staging for endometrial cancer during July 2007–July 2008 was collected and analysed. Demographic data and perioperative outcomes were compared between cases performed via laparotomy, laparoscopy and robotics. Results Sixty-five patients underwent staging during the time of data collection (LAP-26, LSC-7, ROB-32). No difference in surgical volume in the year before vs. after robotics was identified. Median operative time for robotics and laparotomy was significantly less than for laparoscopy (p = 0.023). There was no significant difference in lymph node yields between the three groups (p = 0.92). Robotics was associated with significantly less blood loss (p < 0.0001). Complication rates were significantly lower in the robotic group compared to the laparotomy group (p = 0.05). Median hospital stay was 1 day for the minimally invasive groups. Total number of perioperative inpatient days decreased from 331 to 150 in one year. Practice management of endometrial cancer transitioned from a predominantly open approach (5.6% LSC) to robotics (11% LSC, 49% ROB) within 12 months. Conclusions Robotic surgery dramatically altered our management of endometrial cancer and was associated with a significant improvement in several perioperative outcomes when compared to laparotomy and laparoscopy. Copyright © 2009 John Wiley & Sons, Ltd.

A novel 3D classification system for canine impactions—the KPG index

Abstract: Background 3D cone beam imaging allows localization of impacted canines, using spatial relationships, with excellent tissue contrast. The aim of this project was to assess the degree of difficulty for the treatment of impacted canines, based on the 3D information provided by cone beam imaging. Methods 3D cone beam images taken from subjects with impacted canines were obtained from a private practice and school setting. Results A novel measuring scale was devised, based on three different viewpoints, in order to grade the difficulty of impaction and the potential efficacy of treatment. Depending on its anatomical location, the cusp tip and the root tip are each given a number 0–5 in three dimensions taken from a pretreatment image. The sum of the cusp tip and root tip scores in the three views dictated our anticipated difficulty of treatment. Conclusions A novel method of analysing impactions using cone beam imaging was proposed. This method utilizes the entire three views of a CBCT image. Copyright © 2009 John Wiley & Sons, Ltd.

Optimization of a novel mechanism for a minimally invasive surgery robot.

Abstract: Background Minimally invasive surgery (MIS) has many advantages compared with open surgery, but there are still many drawbacks in performing MIS. Using robotic technologies, many problems caused by human restrictions, such as fatigue and low precision, can be solved. In this paper, a novel mechanism for a MIS robot is proposed. Methods Kinematics analysis was carried out and singularity and isotropy configurations were also investigated, based on kinematics equations. In order to evaluate the performance of the robot, a combined measure gave attention to the mean value and standard deviation of the reciprocal of the condition number. Optimization was achieved by maximizing the combined measure subjected to a set of constraints in the task workspace. The effectiveness of the measure was demonstrated by comparing the performance and volume of the optimized mechanism with those of the mechanism optimized by the Global Condition Index (GCI). Results The robot met the volume constraints with the dimensional parameter a ≤ 115 mm. The combined measure φ was maximized when a is 100 mm. The robots optimized by the GCI and the combined measure showed similar performance in terms of condition number, but the latter had advantages on volume compared with the former. Conclusions A novel mechanism that satisfied the incision point constraint of MIS was proposed. A systematic methodology for optimizing the mechanism was developed and the combined measure was effective to evaluate the performance. A prototype was set up based on the outcomes mentioned in the paper. Copyright © 2009 John Wiley & Sons, Ltd.

Target registration and target positioning errors in computer-assisted neurosurgery: proposal for a standardized reporting of error assessment.

Abstract: Background Assessment of errors is essential in development, testing and clinical application of computer-assisted neurosurgery. Our aim was to provide a comprehensive overview of the different methods to assess target registration error (TRE) and target positioning error (TPE) and to develop a proposal for a standardized reporting of error assessment. Methods A PubMed research on phantom, cadaver or clinical studies on TRE and TPE has been perfomed. Reporting standards have been defined according to (a) study design and evaluation methods and (b) specifications of the navigation technology. Results The proposed standardized reporting includes (a) study design (controlled, non-controlled), study type (non-anthropomorphic phantom, anthropomorphic phantom, cadaver, patient), target design, error type and subtypes, space of TPE measurement, statistics, and (b) image modality, scan parameters, tracking technology, registration procedure and targeting technique. Conclusions Adoption of the proposed standardized reporting may help in the understanding and comparability of different accuracy reports. Copyright © 2009 John Wiley & Sons, Ltd.

Development of a piezo‐actuated micro‐teleoperation system for cell manipulation

Abstract: Background Intracytoplasmic sperm injection (ICSI) requires long training and has low success rates, primarily due to poor control over the injection force. Making force feedback available to the operator will improve the success rate of the injection task. A macro–micro-teleoperation system bridges the gap between the task performed at the micro-level and the macroscopic movements of the operator. The teleoperation slave manipulator should accurately position a needle to precisely penetrate a cell membrane. Piezoelectric actuators are widely used in micromanipulation applications; however, hysteresis non-linearity limits the accuracy of these actuators. Method This paper presents a novel approach for utilizing a piezoelectric nano-stage as slave manipulator of a teleoperation system. The Prandtl–Ishlinskii (PI) model is used to model actuator hysteresis in a feedforward scheme to cancel out this non-linearity. To deal with the influence of parametric uncertainties, unmodelled dynamics and PI identification error, a perturbation term is added to the slave model and applies a sliding mode-based impedance control with perturbation estimation. Results The stability of entire system is guaranteed by Llewellyn's absolute stability criterion. The performance of the proposed controller was investigated through experiments for cell membrane penetration. Conclusion The experimental results verified the accurate position tracking in free motion and simultaneous position and force tracking in contact with a low stiffness environment. Copyright © 2009 John Wiley & Sons, Ltd.

Robotic ultrasound-guided prostate intervention device: system description and results from phantom studies

Abstract: Background We introduce the first robotic ultrasound-guided prostate intervention device and evaluate its safety, accuracy and repeatability. Methods The robotic positioning system (RPS) determines a target's x, y and z axes. It is situated with a biplane ultrasound probe on a mobile horizontal platform. The integrated software acquires ultrasound images for three-dimensional (3D) modelling, coordinates target planning and directs the RPS. Results The egg phantom evaluates the software's safety and workflow protocol. Two random targets are planned in each quadrant and biopsy needles are inserted. All were within three separate eggs. Metal wire tips are targeted and their distances from the biopsy needle tips are measured. With 20 wires, < 1 mm accuracy is obtained. Repeatability is demonstrated when previous positions are returned to with similar accuracy. Conclusion Our device demonstrates safety in a defined boundary with a repeatable accuracy of < 1 mm. It can be used for accurate prostate biopsy and treatment delivery. Copyright © 2009 John Wiley & Sons, Ltd.

Application of computer-aided three-dimensional skull model with rapid prototyping technique in repair of zygomatico-orbito-maxillary complex fracture.

Abstract: Background With the advent of CAD/CAM and rapid prototyping (RP), a technical revolution in oral and maxillofacial trauma was promoted to benefit treatment, repair of maxillofacial fractures and reconstruction of maxillofacial defects. Methods For a patient with zygomatico-facial collapse deformity resulting from a zygomatico-orbito-maxillary complex (ZOMC) fracture, CT scan data were processed by using Mimics 10.0 for three-dimensional (3D) reconstruction. The reduction design was aided by 3D virtual imaging and the 3D skull model was reproduced using the RP technique. In line with the design by Mimics, presurgery was performed on the 3D skull model and the semi-coronal incision was taken for reduction of ZOMC fracture, based on the outcome from the presurgery. Results Postoperative CT and images revealed significantly modified zygomatic collapse and zygomatic arch rise and well-modified facial symmetry. Conclusions The CAD/CAM and RP technique is a relatively useful tool that can assist surgeons with reconstruction of the maxillofacial skeleton, especially in repairs of ZOMC fracture. Copyright © 2009 John Wiley & Sons, Ltd.

Measuring leg length and offset with an imageless navigation system during total hip arthroplasty: is it really accurate?

Abstract: Background A novel imageless measurement algorithm to assess leg length (LL) and offset (OS) changes during total hip arthroplasty (THA) has been established, the purpose of this study was to describe the process and establish whether or not it is accurate. Methods THA was performed on 17 cadaver hip specimens. LL and OS changes were determined intra-operatively, using an imageless navigation system. Pre- and postoperatively, all specimens had a computed tomography scan (CT) and the LL and OS changes were analysed by two blinded investigators. Results With mean differences of less than 1 mm (LL, 0.74; SD, 2.4 mm; OS, 0.89; SD, 1.8 mm) supported by substantial significant correlations [r = 0.83 (LL) and r = 0.92 (OS)] imageless navigation values demonstrated a high accuracy when compared to CT measurements. Conclusions Intra-operative LL and OS measures are reliable and accurate when using an imageless calculation algorithm which stores the position of the femoral reference frame in relation to the pelvic coordinate system before and after reconstruction. Copyright © 2009 John Wiley & Sons, Ltd.

Accuracy in planar cutting of bones: an ISO-based evaluation.

Abstract: BACKGROUND: Computer- and robot-assisted technologies are capable of improving the accuracy of planar cutting in orthopaedic surgery. This study is a first step toward formulating and validating a new evaluation methodology for planar bone cutting, based on the standards from the International Organization for Standardization. METHODS: Our experimental test bed consisted of a purely geometrical model of the cutting process around a simulated bone. Cuts were performed at three levels of surgical assistance: unassisted, computer-assisted and robot-assisted. We measured three parameters of the standard ISO1101:2004: flatness, parallelism and location of the cut plane. RESULTS: The location was the most relevant parameter for assessing cutting errors. The three levels of assistance were easily distinguished using the location parameter. CONCLUSIONS: Our ISO methodology employs the location to obtain all information about translational and rotational cutting errors. Location may be used on any osseous structure to compare the performance of existing assistance technologies. Copyright (c) 2009 John Wiley & Sons, Ltd.

Design and preliminary in vivo validation of a robotic laparoscope holder for minimally invasive surgery.

Abstract: BACKGROUND: Manual manipulation of the camera is a major source of difficulties encountered by surgeons while performing minimally invasive laparoscopic surgery. METHODS: A survey of laparoscopic procedures and a review of existing active and passive holders were conducted. Based on these analyses, essential requirements were highlighted for such devices. Pursuant to this, a novel active laparoscope manipulator was designed, paying particular attention to ergonomics and ease of use. Several trials on the pelvitrainer and a first in vivo procedure were performed to validate the original design of our device. RESULTS: Phantom experiments demonstrated ease of use of the robot and advantages of the intuitive joystick with omnidirectional displacements and speed control. The compactness of the device and image stability were appreciated during the surgical trial. CONCLUSIONS: A novel robotic laparoscope holder has been developed and produced. An in vivo trial proved its value in clinical practice, enabling surgeons to work more comfortably. Copyright (c) 2009 John Wiley & Sons, Ltd.

Improving target registration accuracy in image-guided neurosurgery by optimizing the distribution of fiducial points.

Abstract: Background The point-pair method is widely used to register the patient space and the image space in image-guided neuro surgery. In this kind of registration, the distribution of fiducial points has a great influence on the registration accuracy at the target point. Methods In this paper we propose the idea of target registration accuracy contribution (TRAC) of current fiducial points and of candidate fiducial points. Based on these two values, we give an interactive method to help the surgeon optimize the distribution of fiducial points so as to improve the registration accuracy at the target point. Results The experiments on real patients' data showed that this approach reduced approximately half of the registration error at the target point introduced by unsuitable distribution of fiducial points. When transferring the optimized distribution to real patients, the target registration accuracy obtained from optimization had no serious deterioration. Conclusion This study provides a practical approach for neurosurgeons to arrange the fiducial points properly on a patient's head. Copyright © 2008 John Wiley & Sons, Ltd.

Tailor-made surgical guide based on rapid prototyping technique for cup insertion in total hip arthroplasty.

Abstract: Background A surgical guide made by the rapid prototyping (RP) technique for cup insertion in total hip arthroplasty might be useful to avoid malalignment of the cup, which indicates postoperative complications. Methods To address this research question, we applied a RP-based guide to 24 patients with their CT images. We designed it to fit onto the acetabular edge and to insert a Kirschner wire (K-wire) which indicated a planned cup direction. We intraoperatively placed it on the acetabular edge, inserted the K-wire through the guide on the superior acetabulum and implanted the cup while observing the alignment of the K-wire. We also recorded the additional time needed to use the guide. Results The mean cup accuracy between planned and postoperative alignments was 2.8° (SD = 2.1° ) for abduction and 3.7° (SD = 2.7° ) for anteversion. The mean additional time was 3.5 (range 2–6) min. Conclusion We can use this guide with acceptable accuracy and without consuming an excessive amount of time. Copyright © 2009 John Wiley & Sons, Ltd.

Skeleton-based active catheter navigation.

Abstract: Background The emergence of the active catheter has prompted the development of catheterization in minimally invasive surgery. However, it is still operated using only the physician's vision; information supplied by the guiding image and tracking sensors has not been fully utilized. Methods In order to supply the active catheter with more useful information for automatic navigation, we extract the skeleton of blood vessels by means of an improved distance transform method, and then present the crucial geometric information determining navigation. With the help of tracking sensors' position and pose information, two operations, advancement in the proximal end and direction selection in the distal end, are alternately implemented to insert the active catheter into a target blood vessel. Results The skeleton of the aortic arch reconstructed from slice images is extracted fast and automatically. A navigation path is generated on the skeleton by manually selecting the start and target points, and smoothed with the cubic cardinal spline curve. Crucial geometric information determining navigation is presented, as well as requirements for the catheter entering the target blood vessel. Using a shape memory alloy active catheter integrated with magnetic sensors, an experiment is carried out in a vascular model, in which the catheter is successfully inserted from the ascending aorta, via the aortic arch, into the brachiocephalic trunk. Conclusions The navigation strategy proposed in this paper is feasible and has the advantage of increasing the automation of catheterization, enhancing the manoeuvrability of the active catheter and providing the guiding image with desirable interactivity. Copyright © 2009 John Wiley & Sons, Ltd.

Impact of IQ, computer-gaming skills, general dexterity, and laparoscopic experience on performance with the da Vinci surgical system

Abstract: BACKGROUND: Due to improved ergonomics and dexterity, robotic surgery is promoted as being easily performed by surgeons with no special skills necessary. We tested this hypothesis by measuring IQ elements, computer gaming skills, general dexterity with chopsticks, and evaluating laparoscopic experience in correlation to performance ability with the da Vinci robot. METHODS: Thirty-four individuals were tested for robotic dexterity, IQ elements, computer-gaming skills and general dexterity. Eighteen surgically inexperienced and 16 laparoscopically trained surgeons were included. Each individual performed three different tasks with the da Vinci surgical system and their times were recorded. An IQ test (elements: logical thinking, 3D imagination and technical understanding) was completed by each participant. Computer skills were tested with a simple computer game (hand-eye coordination) and general dexterity was evaluated by the ability to use chopsticks. RESULTS: We found no correlation between logical thinking, 3D imagination and robotic skills. Both computer gaming and general dexterity showed a slight but non-significant improvement in performance with the da Vinci robot (p > 0.05). A significant correlation between robotic skills, technical understanding and laparoscopic experience was observed (p < 0.05). CONCLUSIONS: The data support the conclusion that there are no significant correlations between robotic performance and logical thinking, 3D understanding, computer gaming skills and general dexterity. A correlation between robotic skills and technical understanding may exist. Laparoscopic experience seems to be the strongest predictor of performance with the da Vinci surgical system. Generally, it appears difficult to determine non-surgical predictors for robotic surgery.

Long-term results of quality of life after standard laparoscopic vs. robot-assisted laparoscopic fundoplications for gastro-oesophageal reflux disease. A comparative clinical trial.

Abstract: Background The role of telematic surgical approach in gastro-oesophageal reflux disease (GERD) is still unclear. Methods The aim of the study is to assess disease specific symptoms and quality of life in patients with GERD treated with either traditional laparoscopic (TL) or robot-assisted fundoplication using the Da Vinci™ system (DV) in long-term follow-up. Results Eighty patients underwent a fundoplication in 2003. Four years later all patients were given a standardized questionnaire and 59 (74%) replied. The TL group included 44 patients (18 male/26 female) and the DV group 15 patients (9 male/6 female); the mean operating time was 116 min for the TL group and 207 min for the DV group (p 0.05). Conclusions Although a safe and feasible procedure, high functional costs of the Da Vinci system and longer operating time prevent this operation from being the standard surgical procedure for GERD. Copyright © 2008 John Wiley & Sons, Ltd.

Comparison of navigation accuracy in THA between the mini-anterior and -posterior approaches

Abstract: Background The accuracy of a CT-based hip navigation might depend on surgical approaches, resulting in varying accuracy of implant alignment. Methods We performed primary cementless total hip arthroplasty (THA) with mini-incision surgery (MIS) to 40 well-matched patients (anterior or posterior approaches, 20 hips each), using navigation with surface registration. We investigated cup alignment using postoperative computed tomography (CT) and compared the navigation accuracy between the two approaches, i.e. the difference between intra-operative and postoperative alignments of the cup. Results There was no significant difference between the two approaches. The mean navigation accuracies in abduction and anteversion were 2.0° (SD 1.4° ) and 2.7° (SD 1.9° ), respectively, in the anterior approach, and 2.4° (SD 2.0° ) and 2.0° (SD 1.4° ), respectively, in the posterior approach. All cup alignments were within 10° of the target orientation. Conclusions This CT-based navigation for MIS–THA provides navigation accuracy without significant differences between the two approaches and with favourable alignment of the cup. Copyright © 2008 John Wiley & Sons, Ltd.

A medical tactile sensing instrument for detecting embedded objects, with specific application for breast examination.

Abstract: Background In this paper, having considered the tactile sensing and palpation of a physician in order to detect abnormal masses in the breast, we simplified and then modelled the tissue containing a mass and used contact elements to analyse the tactile sensor function. Methods By using the finite element method, the effects of the mass existence appeared on the surface of the tissue. This was due to exerting mechanical load on the modelled tissue surface. Following this, a tactile sensing instrument called the ‘tactile tumour detector’ (TTD) was designed and constructed. This device is able to detect abnormal objects in the simulated models by making contact with model surfaces. In order to perform a series of precise experiments, a robot that could hold the tactile probe was used. The velocity of the linear movement of the probe is low enough to ensure that the tissue behaves in the linear elastic range, so that dynamic effects can be neglected. Results and Discussion The maximum value of stresses was chosen as the comparison criterion. The variation of this criterion vs. the mass parameter changes was investigated and good agreements between numerical and experimental results were obtained. Moreover, the sensitivity and specificity of TTD and clinical breast examination (CBE) in the detection of breast masses, in comparison to sonography as the ‘gold standard’, were calculated by performing clinical trials on 55 cases. Copyright © 2009 John Wiley & Sons, Ltd.

HyBAR: hybrid bone-attached robot for joint arthroplasty

Abstract: Background A number of small bone-attached surgical robots have been introduced to overcome some disadvantages of large stand-alone surgical robots. In orthopaedics, increasing demand on minimally invasive joint replacement surgery has also been encouraging small surgical robot developments. Among various technical aspects of such an approach, optimal miniaturization that maintains structural strength for high speed bone removal was investigated. Methods By observing advantages and disadvantages from serial and parallel robot structures, a new hybrid kinematic configuration was designed for a bone-attached robot to perform precision bone removal for cutting the femoral implant cavity during patellofemoral joint arthroplasty surgery. A series of experimental tests were conducted in order to evaluate the performance of the new robot, especially with respect to accuracy of bone preparation. Results A miniaturized and rigidly-structured robot prototype was developed for minimally invasive bone-attached robotic surgery. A new minimally invasive modular clamping system was also introduced to enhance the robotic procedure. Foam and pig bone experimental results demonstrated a successful implementation of the new robot that eliminated a number of major design problems of a previous prototype. Conclusions For small bone-attached surgical robots that utilize high speed orthopaedic tools, structural rigidity and clamping mechanism are major design issues. The new kinematic configuration using hinged prismatic joints enabled an effective miniaturization with good structural rigidity. Although minor problems still exist at the prototype stage, the new development would be a significant step towards the practical use of such a robot. Copyright © 2009 John Wiley & Sons, Ltd.

Computer-assisted surgery for dynamic hip screw, using Surgix©, a novel intraoperative guiding system

Abstract: Background We present Surgix©, a new computer-assisted surgery system (CASS). This system uses image analysis technology in order to measure three-dimensional (3D) distances, visualize implant templates and view the guided trajectory on standard fluoroscopy. Our purpose was to compare surgery results and technique with and without the Surgix CASS. Methods The study included 61 dynamic hip screw (DHS) procedures. The Surgix system was used in 41 procedures. We compared the number of guide wire insertion trials and the time needed for each trial, the number of X-ray pulses, tip–apex index, nine-quadrant position and shaft–neck angle. Results The procedures were carried out by experienced users (≥ five operations, using the system) and had a first-trial guide wire insertion success rate of 77.8%, compared to a rate of 10% for the control group (p = 0.001) and fewer insertion trials (1.33 vs. 3.05, respectively; p = 0.001). The mean number of fluoroscopy pulses was 41.5% lower for the experienced group than for the control (17.6 vs. 30.1; p = 0.009). There were no significant differences in tip–apex distance, favourable quadrant screw placement or neck–shaft angle. Conclusion The results of this study demonstrate that the Surgix CASS significantly improves the accuracy of hardware positioning and reduces radiation exposure time, thus enhancing patient outcome. Copyright © 2008 John Wiley & Sons, Ltd.

Graphic and haptic modelling of the oesophagus for VR-based medical simulation.

Abstract: Background Medical simulators with vision and haptic feedback have been applied to many medical procedures in recent years, due to their safe and repetitive nature for training. Among the many technical components of the simulators, realistic and interactive organ modelling stands out as a key issue for judging the fidelity of the simulation. This paper describes the modelling of an oesophagus for a real-time laparoscopic surgical simulator. Methods For realistic simulation, organ deformation and tissue cutting in the oesophagus are implemented with geometric organ models segmented from the Visible Human Dataset. The tissue mechanical parameters were obtained from in vivo animal experiments and integrated with graphic and haptic devices into the laparoscopic surgical simulation system inside an abdominal mannequin. Results This platform can be used to demonstrate deformation and incision of the oesophagus by surgical instruments, where the user can haptically interact with the virtual soft tissues and simultaneously see the corresponding organ deformation on the visual display. Conclusions Current laparoscopic surgical training has been transformed from the traditional apprenticeship model to simulation-based methods. The outcome of the model could replace conventional training systems and could be useful in effectively transferring surgical skills to novice surgeons. Copyright  2009 John Wiley & Sons, Ltd.