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PubMed2002

Objective surgical performance evaluation based on haptic feedback.

In order to develop effective virtual reality training systems for surgery there is a need to provide appropriate sensory and performance feedback to the user. This paper aims to demonstrate a method by which performance data can be collected. This is used to investigate the effect of haptic feedback on performance. A PHANTOM desktop device was used in conjunction with a suturing simulation A pair of needle-holders was instrumented with strain gauges and attached to the stylus of the PHANTOM allowing the measurement of force application and time. Suturing performance was evaluated in terms of stitch completion time, peak force application, and the length and straightness of the stitch. The effect of the level of force feedback provided by the simulation and performance over time was considered. The results indicate that the presence of force feedback affected task completion time, peak force application and the straightness of the stitch. Task completion time was shown to increase with the level of force feedback provided. Performance was seen to improve over time in terms of task completion time and the accuracy ofthe stitch. The work has examined how the presence and level of force feedback affects performance of a simple task. The accuracy of haptic feedback is important in the design of surgical simulation systems to ensure effective training transfer. A data collection method by which objective performance evaluation can be made is demonstrated. The method can be applied to training using bench models, simulations and potentially in the operating theatre.

Clinical Competence↗
PubMedDate not supplied

Robotics, telesurgery and telementoring--their position in modern urological laparoscopy.

OBJECTIVES: Laparoscopic surgery in general is handicapped by the reduction of the range of motion from six to four degrees of freedom. This has a major impact on technically difficult procedures such as laparoscopic radical prostatectomy. Solutions for this problems include the understanding of the geometry of laparoscopy with sophisticated training programs, but lie also in newly developed surgical robots, computer simulators and telementoring. This article evaluates the value of these alternatives based on own experiences and an analysis of the current literature. METHODS: Own experiences with robot-assisted surgery include 406 laparoscopic radical prostatectomies using a voice-controlled camera-arm (AESOP) as well as 6 telesurgical interventions with the Da Vinci-system. Additionally, substantial experimental studies have been performed focussing on the geometry of laparoscopy and new training concepts such as perfused pelvitrainers and computer simulation. Moreover, the current literature of the last 10 years on telesurgery and telementoring has been reviewed. RESULTS: The geometry of laparoscopy includes the angles between the instruments which have to be in a range of 25 degrees to 45 degrees; the angles between the instrument and the working plane that should not exceed 55 degrees; and the angle between the shaft of the needle holder and the needle which has to be adapted according to the anatomical situation in range of 90 to 110 degrees. 3-D-systems did not yet proved to be effective due to handling problems such as shutter glasses, video-helmets or reduced brightness. At the moment, there are only two robotic surgical systems (ZEUS, Da Vinci) in clinical use for telesurgery, of which only the Da Vinci provides stereovision and all six degrees of freedom (DOF). In the meantime, more than 200 laparoscopic radical prostatectomies have been performed with this system. Until now, however, there was no evidence of any advantages over the conventional laparoscopic approach. The ZEUS in combination with the telecommunication system SOKRATES is the only device enabling to realize telemanipulation and telementoring over long distances (i.e. transatlantic). CONCLUSION: Robotic surgery represents a turning point of surgical research. However, broad use of robotic systems is limited mainly because of the high investment and running costs. Whereas there will be a clear role of audio-visual telementoring in future training concepts, the need of telemanipulation/telesurgery has not yet been clarified. New technological concepts promote the development of hand-held mechanical manipulators (i.e. 6-DOF-needle-holder) used in combination with mono-tasking computerized robots (i.e. AESOP) resulting in a significant cost reduction.

Computer Simulation↗
PubMed2006

Virtual reality ureteroscopy simulator as a valid tool for assessing endourological skills.

AIM: Virtual reality (VR) simulators are now commercially available for various surgical skills training. The Uro Mentor VR Ureteroscopy Simulator by Symbionix is one system that may revolutionize the way we assess and teach surgical residents. Surgical educators may no longer have to depend on the operating room as the sole venue for teaching residents technical skills. We validated performance on this new system with previously developed assessment tools and compared it to performance on a high fidelity ureteroscopy bench model. METHODS: Urology residents (n = 16) were assessed on their ability to perform cystoscopy, guidewire insertion, semirigid ureteroscopy and basket extraction of a distal ureteric stone on the VR simulator. A blinded examiner assessed subject performance using a checklist, global rating scale and a pass/fail rating. In addition, computer-generated parameters including time to complete task, scope and instrument trauma and the number of attempts to insert a guidewire were analysed. Performance on the VR simulator was compared to performance on a high fidelity ureteroscopy bench model. RESULTS: Senior residents (n = 8) scored significantly higher on their global rating scale (29.4 +/- 2.5 vs 20.8 +/- 0.9, P = 0.005), checklist (19.1 +/- 1.1 vs 15.2 +/- 0.9, P = 0.02), pass/fail rating (chi(2) = 7.3, P = 0.007) and required less time to complete the task (352.9 +/- 55.7 s vs 576.8 +/- 67.4 s., P = 0.02) than the junior residents (n = 8) on the VR simulator. Junior residents also had a significantly higher incidence of scope trauma (4 vs 0.6, P = 0.02). No significant differences were noted in instrument trauma and the number of attempts to insert the guidewire. Global rating scale performance on the VR simulator correlated well to performance on the high fidelity ureteroscopy bench model (r = 0.7, P = 0.002) as did time to complete task (r = 0.7, P = 0.004). CONCLUSIONS: The Uro Mentor VR Ureteroscopy Simulator is a useful tool in assessing resident endourological skills. Performance on the VR simulator is comparable to a validated high fidelity ureteroscopy bench model. Future studies will assess the utility of VR simulators in surgical skills training.

Adult↗
PubMed2002

Cryotherapy simulator for localized prostate cancer.

Cryotherapy is a treatment modality that uses a technique to selectively freeze tissue and thereby cause controlled tissue destruction. The procedure involves placement of multiple small diameter probes through the perineum into the prostate tissue at selected spatial intervals. Transrectal ultrasound is used to properly position the cylindrical probes before activation of the liquid Argon cooling element, which lowers the tissue temperature below -40 degrees Centigrade. Tissue effect is monitored by transrectal ultrasound changes as well as thermocouples placed in the tissue. The computer-based cryotherapy simulation system mimics the major surgical steps involved in the procedure. The simulated real-time ultrasound display is generated from 3-D ultrasound datasets where the interaction of the ultrasound with the instruments as well as the frozen tissue is simulated by image processing. The thermal and mechanical simulations of the tissue are done using a modified finite-difference/finite-element method optimized for real-time performance. The simulator developed is a part of a comprehensive training program, including a computer-based learning system and hands-on training program with a proctor, designed to familiarize the physician with the technique and equipment involved.

Computer Simulation↗
PubMed2000

Vitreous surgery simulator.

OBJECTIVE: To reduce the surgical risks to patients and expose surgeons to surgical experience and complications, we have developed a practical system of vitreous surgery using virtual-reality technology. METHODS: The system is composed of high-resolution color stereo binoculars, haptic devices, foot switches, and a high-speed graphics computer. To simulate vitreous surgery, we created several virtual patient eyes with retinal diseases such as preretinal membranes and subretinal neovascular tissue at the fovea. RESULTS: The simulator provided the trainees with an operating environment similar to an actual one, and allowed them to learn to maneuver surgical instruments and remove proliferative tissue on the retina, under the retina, or both. This system allowed surgeons to avoid iatrogenic complications through visual signs such as retinal hemorrhage when the instrument contacted the retinal surface. CONCLUSIONS: This simulator may not only be suitable for residents to learn ocular surgical techniques but may also allow veteran surgeons to develop new surgical methods and skills.

Computer Simulation↗
PubMed2004

Lift-up laminoplasty for myelopathy caused by ossification of the posterior longitudinal ligament of the cervical spine.

BACKGROUND AND AIMS: We have utilized lift-up laminoplasty to treat patients with myelopathy caused by ossification of the posterior longitudinal ligament (OPLL) of the cervical spine. The preliminary surgical outcome with computer-assisted morphological assessment is presented. MATERIAL AND METHODS: The surgical technique of lift-up laminoplasty includes standard posterior exposure of the cervical spine, en-bloc laminectomy, and expansion of the cervical canal by lift-up of the laminae with custom-designed hydroxyapatite laminar spacers and stabilization of the laminae using titanium miniplates. From 1998 to 2003, 10 consecutive patients with cervical myelopathy secondary to OPLL have been treated with this method and comprehensively evaluated. Care was taken to tailor the treatment to individual patients by using different sizes of spacers to adjust the degree of expansion depending on the amount of stenosis of the cervical spine. The degree of expansion of the cervical canal was altered by design, based on the preoperative imaging simulation. RESULTS: Preliminary surgical outcome, evaluated at 6 months after surgery, revealed a significant improvement of neurological function. Image analysis revealed that the cervical canals were significantly expanded, with a mean reduction of 13.1% in the stenosis ratio. Lift-up laminoplasty was effective in the treatment of patients with myelopathy secondary to cervical OPLL, and the amount of expansion could be individually adjusted at the discretion of the surgeon. CONCLUSION: Although analysis with a larger population and a longer follow-up period needs to be undertaken, our method of lift-up laminoplasty appears to be a viable choice among standard posterior cervical approaches for cervical OPLL.

Aged↗
PubMed2000

[Virtual reality in neurosurgery].

DEFINITION: Virtual reality enables users to immerse themselves in a virtual three-dimensional world and to interact in this world. The simulation is different from the kind in computer games, in which the viewer is active but acts in a nonrealistic world, or on the TV screen, where we are passively driven in an active world. In virtual reality elements look realistic, they change their characteristics and have almost real-world unpredictability. USE OF VIRTUAL REALITY: Virtual reality is not only implemented in gambling dens and the entertainment industry but also in manufacturing processes (cars, furniture etc.), military applications and medicine. Especially the last two areas are strongly correlated, because telemedicine or telesurgery was originated for military reasons to operate on war victims from a secure distance or to perform surgery on astronauts in an orbiting space station. In medicine and especially neurosurgery virtual-reality methods are used for education, surgical planning and simulation on a virtual patient.

Endoscopes↗
PubMed1995

Clinical evaluation of a system for precision enhancement in spine surgery.

Most techniques in segmental spinal fixation surgery rely on the identification of predefined targets with the help of anatomical landmarks and on intraoperative use of image intensifiers. However, because there is no direct link between the image information, the accessible spinal anatomy, and the action of surgical instruments several potential problems and possible complications are still involved. A novel system for spinal surgery has been designed allowing for the real-time, intraoperative localization of surgical instruments in medical images. In practice this was achieved by combining image-guided stereotaxis with advanced optoelectronic position sensing techniques. Modules were developed for image data processing, surgical planning and simulation, and various intraoperative procedures. A detailed validation of the system was performed indicating an overall accuracy to be better than the slice distance of the spinal image used. In an in-vitro setting 20 pilot holes for pedicle screws were prepared in human cadaveric lumbar spines. An analysis in 77 histological cuts showed an ideal location in 70 and only minor cortex engagement in seven sections. In vivo the system has been successfully applied in three posterior low lumbar stabilizations with overall 15 transpedicular screws. RELEVANCE--:This article focuses on the clinical evaluation of a computer-assisted surgery system and its application to the operating theatre for transpedicular fixation of the spine. The given approach effectively keeps the surgeon 'in the loop' and requires only minor modifications of the established surgical techniques and associated instruments. The results of this study indicate that advanced computer-assisted techniques may significantly improve the accuracy and safety of surgical interventions of the spine. The proposed technique may in future be adapted to other applications in orthopaedic surgery.

Journal Article↗
PubMed2005

Tearing of membranes for interactive real-time surgical training.

Tearing for interactive real-time surgical training is a problem rarely discussed in scientific publications. In this paper, an approach is presented to model the tearing of membranes. Based on a mesh of mass nodes connected by springs and triangles tears propagate along the springs of the mesh. Springs and triangles at the crack are divided up between both sides, keeping the number of triangles constant. Node stress indicates when and where the membrane tears. Tear threshold of a node depends on the node's location in the mesh. Edge nodes tear more easily than internal nodes. Nodes at the end of a crack have the lowest threshold to favor the propagation of already created cracks. Compared to a straightforward solution of the problem, the deletion of over stretched springs, the approach has some advantages. The presented algorithm shows a more plausible result for small resolutions that are used by the real-time simulation of stiff materials. On high-resolution meshes, there is only little difference between both approaches. Two training modules for the ophthalmo-surgical simulator EYESI use the presented tearing method to model realistic membrane tearing.

Algorithms↗
PubMed2006

Transversely isotropic properties of porcine liver tissue: experiments and constitutive modelling.

Knowledge of the biomechanical properties of soft tissue, such as liver, is important in modelling computer aided surgical procedures. Liver tissue does not bear mechanical loads, and, in numerical simulation research, is typically assumed to be isotropic. Nevertheless, a typical biological soft tissue is anisotropic. In vitro uniaxial tension and compression experiments were conducted on porcine cylindrical and cubical liver tissue samples respectively assuming a simplistic architecture of liver tissue with its constituent lobule and connective tissues components. With the primary axis perpendicular to the cross sectional surface of samples, the tissue is stiffer with tensile or compressive force in the axial direction compared to that of the transverse direction. At 20% strain, about twice as much force is required to elongate a longitudinal tissue sample than that of a transverse sample. Results of the study suggest that liver tissue is transversely isotropic. A combined strain energy based constitutive equation for transversely isotropic material is proposed. The improved capability of this equation to model the experimental data compared to its previously disclosed isotropic version suggests that the assumption on the fourth invariant in the constitutive equation is probably correct and that anisotropy properties of liver tissue should be considered in surgical simulation.

Animals↗
PubMed2004

Antibiotic prophylaxis influences cardiovascular stability in complicated surgery.

OBJECTIVE: Antibiotic prophylaxis is used in many surgical procedures but there are frequent cardiovascular instabilities following antibiotics in perioperative period. A clinic modelling randomised trial (CMRT) in pigs was developed to compare the effects of 2 commonly used antibiotic combinations on cardiovascular stability during major surgery. MATERIALS AND METHODS: Thirty pigs (both sexes) were randomised into 3 groups, receiving either saline (placebo), co-amoxiclav or cefuroxime/metronidazole in clinically relevant doses as antibiotic prophylaxis. A laparotomy was performed and the abdomen remained open. Surgical complications were simulated by removing one third of the blood volume. For fluid resuscitation, 500 ml hetastarch (HAES(TM)) were infused rapidly (therapy of complication) and polymyxin B (15 mg/kg bodyweight) was applied for induction of histamine release reactions (complication of therapy). The main end points were histamine release reactions, these were classified by 2 blinded investigators. RESULTS: Neither cardiovascular changes nor histamine release reactions were detected immediately after the administration of antibiotics or placebo alone. Plasma histamine concentrations increased after bleeding in the co-amoxiclav group (p < 0.05). After fluid resuscitation and induction of anaphylactoid reactions, the median histamine release and cardiovascular changes were not significantly different between the groups. However, the incidence of typical histamine release related reactions differed significantly between the groups: 8/10 for the controls, 6/10 in the co-amoxiclav and 2/10 in the cefuroxime/metronidazole group (p < 0.05). CONCLUSIONS: The stability and reproducibility of this model clearly demonstrated the concept of a 'clinic modelling randomised trial' as a useful tool. Antibiotic prophylaxis influences the organism's capability to cope with intraoperative bleeding and fluid resuscitation problems. Indeed antibiotic prophylaxis may be beneficial. These effects of antibiotics could only be demonstrated in complex surgical models. Thus new antibiotics should be investigated in complex animal models prior to prospective randomised clinical trials or usage in clinical practice.

Animals↗
PubMed2005

LapSim virtual reality laparoscopic simulator reflects clinical experience in German surgeons.

BACKGROUND AND AIMS: The aim of this study was to analyze the ability of a training module on a virtual laparoscopic simulator to assess surgical experience in laparoscopy. METHODS: One hundred and fifteen participants at the 120th annual convent of the German surgical society took part in this study. All participants were stratified into two groups, one with laparoscopic experience of less than 50 operations (group 1, n=61) and one with laparoscopic experience of more than 50 laparoscopic operations (group 2, n=54). All subjects completed a laparoscopic training module consisting of five different exercises for navigation, coordination, grasping, cutting and clipping. The time to perform each task was measured, as were the path lengths of the instruments and their respective angles representing the economy of the movements. Results between groups were compared using chi(2) or Mann-Whitney U-test. RESULTS: Group 1 needed more time for completion of the exercises (median 424 s, range 99-1,376 s) than group 2 (median 315 s, range 168-625 s) (P<0.01). Instrument movements were less economic in group 1 with larger angular pathways, e.g. in the cutting exercise (median 352 degrees , range 104-1,628 degrees vs median 204 degrees , range 107-444 degrees , P<0.01), and longer path lengths (each instrument P<0.05). CONCLUSION: As time for completion of exercises, instrument path lengths and angular paths are indicators of clinical experience, it can be concluded that laparoscopic skills acquired in the operating room transfer into virtual reality. A laparoscopic simulator can serve as an instrument for the assessment of experience in laparoscopic surgery.

Chi-Square Distribution↗
PubMed2001

Pharmacologic, but not dietary, genistein supports endometriosis in a rat model.

Endometriosis is a disease in which uterine tissue proliferates in extrauterine sites. Using a surgical model to simulate endometriosis, we explored the potential for the phytoestrogen genistein, by injection and diet, to sustain endometriosis in rats. Uterine tissue was attached to intestinal mesentery of 8-week-old Sprague Dawley rats. After 3 weeks, the rats were ovariectomized and the implants measured. Following 3 weeks of daily injections or exposure to dietary genistein, animals were necropsied and implants located and measured. Injections of genistein (50 and 16.6 microg/g BW) or estrone (1 microg/rat) sustained the implants; injection of sesame oil (vehicle for estrone), dimethylsulfoxide (DMSO; vehicle for genistein), or genistein at 5.0 microg/g BW did not sustain implants. Dietary genistein (250 or 1000 mg genistein/kg AIN-76A diet) did not support the implants. In ovary-intact rats exposed to 250 mg genistein/kg AIN-76A diet, implant size was not altered, compared to control-fed animals. To assess estrogenic actions of genistein, we measured uterine estrogen receptor alpha (ER-alpha) and progesterone receptor (PR) isoforms A and B by Western blot analyses. Injections of estrone or genistein (50 or 16.6 microg/g BW) significantly reduced uterine ER-alpha compared to vehicle-treated animals. PR (B) was significantly increased by all injected doses of genistein or estrone and by the higher dietary dose (1000 mg genistein/kg AIN-76A). PR (A) was significantly increased by injected doses of genistein (16.6 and 5.0 microg/g BW). We conclude that pharmacologic injections, but not dietary physiological concentrations of genistein, support surgically induced endometriosis in rats. Our results suggest a critical role for ER modulation and genistein bioavailability in the maintenance of the implants.

Animals↗
PubMed2002

Volume cutting for virtual petrous bone surgery.

A profound knowledge of anatomy and surgical landmarks of the temporal bone is a basic necessity for any otologic surgeon. Because this knowledge, so far, has been mostly taught by limited temporal bone drilling courses, our objective was to create a system for virtual petrous bone surgery that allows the realistic simulation of specific laterobasal surgical approaches. A major requirement was the development of an interactive drill-like tool, together with a new technique for realistic visualization of simulated cut surfaces. The system is based on a volumetric, high-resolution model of the temporal bone, derived from CT. Interactive volume cutting methods using a new multivolume scheme have been developed. In this scheme, cut regions are modeled independently in additional data volumes using voxelization techniques. The voxelization is adapted to successive cutting operations as needed for the simulation of a drill-like tool. A new visualization technique was developed for artifact-free rendering of sharp edges, as formed by the intersection of a cut and an object surface. The new multivolume visualization technique allows high-quality visualization of interactively generated cut surfaces. This is a necessity for a realistic simulation of petrous bone surgery. Our system therefore facilitates comprehension of the complex morphology, and enables the recognition of surgical landmarks, which is most important if injury to delicate organs (e.g., the facial nerve or auditory ossicles) is to be avoided. The system for virtual petrous bone surgery allows the simulation of specific surgical approaches with high-quality visualization. The user can learn about the complex three-dimensional anatomy of the temporal bone from the viewpoint of a real otosurgical procedure.

Anatomy, Cross-Sectional↗
PubMed2005

Implementation of a Web- and simulation-based curriculum to ease the transition from medical school to surgical internship.

BACKGROUND: Starting a surgical internship is a stressful experience. We developed a web and simulation-based curriculum to ease this transition. METHODS: We created an educational website containing a curriculum of commonly encountered on call situations. After match day in 2003, we contacted all of our new surgical interns. We performed a confidence assessment using a Likert-scale questionnaire, and the trainees were given access to the curriculum. In June 2003, we performed human patient simulator sessions. The participants were asked to provide feedback regarding the simulator experience. During the first week of residency, they were again asked to answer the confidence questionnaire. RESULTS: Sixteen residents (94%) used the web curriculum, and 17 (100%) participated in the simulations. Eleven (65%) filled out both questionnaires. The confidence score improved from 5.4 to 6.7 (P < .0001). CONCLUSIONS: A web and simulation-based curriculum for incoming house staff is feasible. Studies are underway to validate this novel method and to expand its use for surgical education.

Adult↗
PubMed2002

Intractable diplopia after strabismus surgery in adults.

OBJECTIVES: To investigate the incidence of persistent intractable diplopia in adults undergoing surgery for long-standing, constant strabismus and to define tests that may be useful for identifying patients at risk for developing this complication. METHODS: A retrospective medical record review of adults without diplopia undergoing surgery for constant strabismus. RESULTS: Medical records of 424 adult patients undergoing strabismus surgery were studied. Of these patients, 143 (34%) experienced diplopia when tested preoperatively with prisms to simulate the desired surgical outcome. Only 40 patients (9%) had temporary diplopia after surgery, which resolved in all cases by 6 weeks postoperatively. Three patients (0.8%) developed persistent intractable diplopia. Experiencing diplopia with preoperative prism testing was significantly more likely to result in postoperative diplopia than if diplopia was not present preoperatively (P<.001 and P =.04 for temporary and persistent postoperative diplopia, respectively). Preoperative testing had a sensitivity and negative predictive value for temporary postoperative diplopia of 100%, a specificity of 73%, and a positive predictive value of 28%. Similar values were found for persistent diplopia after surgery with the exception of the positive predictive value, which was only 2%. Patients who did not see double during preoperative testing with prisms never developed diplopia after surgery. However, the presence of preoperative diplopia with prism testing (including a prolonged trial with Fresnel prisms) was infrequently predictive of postoperative diplopia. CONCLUSIONS: Intractable diplopia after strabismus surgery in adults without previous diplopia is very rare. The diagnostic use of prisms prior to surgery may identify some patients who have little or no risk of postoperative diplopia, as well as a group of patients with a small but definite risk of intractable postoperative diplopia.

Adolescent↗
PubMed2001

Fixation-based surgery: a new technique for distal radius osteotomy.

OBJECTIVE: The objective was to develop a fixation-based three-dimensional presurgical planner and an intraoperative guidance system for distal radius osteotomy. Fixation-based surgery is a technique premised on using a fixation device, such as a fracture-fixation plate, during the alignment and distraction phases of an osteotomy. MATERIALS AND METHODS: The planning system and guidance system were coded using OpenGL on UNIX workstations. In vitro tests were performed to compare the reproducibility of the computer-enhanced technique to that of the traditional technique, and an in vivo pilot study was initiated. RESULTS: In vitro, the computer-enhanced technique produced a significant reduction by more than one half in both the maximum error of correction and the standard deviation of the correction error. Preliminary in vivo results on six patients suggest that similar error diminution will occur during regular clinical application of the technique. CONCLUSIONS: Both studies showed that the computer system is simple to use. The planning system allowed the surgeon to perform multiple simulations of the surgical procedure preoperatively, which were used to optimize the plan and identify potential problems during realignment. The use of a fixation-based technique avoided the complexity of attempting to guide the surgeon to realign a bone fragment in six degrees of freedom of correction, and eliminated the use of X-ray fluoroscopy for achieving the alignment.

Humans↗
PubMed2001

A new robotic endoscope manipulator. A preliminary trial to evaluate the performance of a voice-operated industrial robot and a human assistant in several simulated and real endoscopic operations.

We report our learning experience in simulated and real surgical tasks with a new voice-controlled robotic endoscope manipulator: an industrial robot with the tool-holder arm modified to support the optic and camera. The manipulator control-card programs have been rewritten to meet the needs of endoscopic surgeons. For this preliminary work, systems engineers with an additional monitor monitored, recorded, and compared the percentage effectiveness and precision of the responses of the robotic and human assistant to successive oral commands during the several different experimental surgical tasks. Simultaneously, to help develop this voice-commanded system for future, more precise robotic manipulation of surgical instruments, they measured the cartesian and spherical coordinates of successive positions of the optic. In unexpectedly difficult experimental conditions, the tireless robot proved more precise and effective than the demonstrably fatigable human: the steadier screen images of the robotic manipulations helped the surgeon tie knots in 7-0 sutures.

Animals↗