Experienced laparoscopic surgeons are automated to the "fulcrum effect": an ergonomic demonstration

Optical angle and visuospatial ability affect basic laparoscopic simulator task performance

Surgical trainees show decreased performance during laparoscopic surgery when the laparoscope (camera) is not aligned with their line of sight towards the operating area. In this study we investigate the influence of visuospatial ability on laparoscopic simulator performance under such non-zero optical angles. Novices were invited to participate in a laparoscopic training session. After completing a visuospatial ability assessment, they performed a simplified laparoscopic task on an in-house developed laparoscopic simulator under eight different optical angles ranging between 0° and 315° in steps of 45°. Data-analysis showed decreased performance under all non-zero optical angles for task duration (mean difference between 1506 and 5049 ms, standard error between 499 and 507, p < .05) and for accuracy under optical angles greater than ±45° (mean difference between 1.48 and 2.11, standard error 0.32, p < .01). Performance-zones were identified for various optical angle ranges and differed for task duration and accuracy. Participants of high visuospatial ability performed significantly better under non-zero angles for accuracy compared to participants of low visuospatial ability (mean difference 0.95, standard error 0.34, p < .01), except for the 180° optical angle (no difference).

Assistance by adaptative damping on a complex bimanual task in laparoscopic surgery

PURPOSE

Laparoscopic surgery has improved outcomes in abdominal surgery, but presents kinematic restrictions for surgeons. Robotic comanipulation with adaptative damping has been investigated in simple laparoscopic tasks. The present protocol aimed to determine the contribution of adaptive damping in complex bimanual tasks approaching clinical setting.

METHODS

Fourteen residents in general surgery performed three exercises, and for each three repetitions without (classic repetitions) and three with robotic assistance (robotic repetitions) in a randomised order. The exercises chosen were trajectory, modified Pea on a Peg and intracorporeal suture. Task performance, gesture performance, workload and impression were measured. Also, a semi-directed interview was performed to collect the participants' feeling about companipulated robots and their potential application in clinical practice.

RESULTS

Adaptative damping assistance did not impact task performance, but allowed an economy of movement in the non-dominant hand during suture exercise (distance 916 ± 500 mm in classic vs. 563 ± 261 mm in robotic, p < 0.001). Perceived workload (p = 0.12) and user's impression were not different between classic and robotic repetitions, except novelty (p < 0.001). Participants' interviews revealed their interest for the robotic devices, particularly the gravity compensation, and were ready to use the adaptative damping provided an intermittent use, for example to dissect dangerous areas.

CONCLUSION

Adaptative damping applied by comanipulated robots does not influence the performance of the task, but improves the performance of the gesture itself, particularly for the non-dominant hand, and during the realisation of a complex task like suturing. For residents in digestive surgery, this assistance does increase workload, and they would use this help in the operating room under certain conditions.

Keep it simple: a crosshair on the screen during proctored laparoscopic surgeries

INTRODUCTION

Inside the operating room, experts use verbal instructions to guide surgical novices through laparoscopic procedures. In this study, we evaluated the use of a crosshair attached to the video monitor, as a hands-free pointing tool to simplify instructions during operation.

METHODS

Ten surgical novices performed two elective laparoscopic cholecystectomies within a week of each other, randomized such that one was performed with and the other without using the crosshair. Directly after operation, questionnaires were completed by the novices and the consultant surgeons. Measures including the comprehensibility of instructions, subjective feeling of safety during preparation, time delays due to different instruction options, and disruptive influence while instructors used the crosshair. Differences in operative performance were evaluated based on the global operative assessment of laparoscopic skills (GOALS) scores.

RESULTS

When the crosshair was used, surgical novices had a better understanding of which anatomical structure should be shown (p = 0.028). Operating time (p = 0.222) and feeling of confidence during preparation did not differ with versus without crosshair use (p = 0.081). All participants stated that the crosshair did not negatively affect the field of vision. In terms of the median GOALS score, the operative performance was improved when the crosshair was used compared with verbal instructions only (median 15, IQR (11; 21) vs. median 12, IQR (5; 19), p < 0.001).

CONCLUSION

The crosshair is a simple, inexpensive, and widely available method to improve communication between instructors and novices in everyday training.

Objective assessment of intraoperative skills for robot-assisted partial nephrectomy (RAPN)

RAPN training usually takes place in-vivo and methods vary across countries/institutions. No common system exists to objectively assess trainee capacity to perform RAPN at predetermined performance levels prior to in-vivo practice. The identification of objective performance metrics for RAPN training is a crucial starting point to improve training and surgical outcomes. The authors sought to examine the reliability, construct and discriminative validity of objective intraoperative performance metrics which best characterize the optimal and suboptimal performance of a reference approach for training novice RAPN surgeons. Seven Novice and 9 Experienced RAPN surgeons video recorded one or two independently performed RAPN procedures in the human. The videos were anonymized and two experienced urology surgeons were trained to reliably score RAPN performance, using previously developed metrics. The assessors were blinded to the performing surgeon, hospital and surgeon group. They independently scored surgeon RAPN performance. Novice and Experienced group performance scores were compared for procedure steps completed and errors made. Each group was divided at the median for Total Errors score, and subgroup scores (i.e., Novice HiErrs and LoErrs, Experienced HiErrs and LoErrs) were compared. The mean inter-rater reliability (IRR) for scoring was 0.95 (range 0.84-1). Compared with Novices, Experienced RAPN surgeons made 69% fewer procedural Total Errors. This difference was accentuated when the LoErr Expert RAPN surgeon's performance was compared with the HiErrs Novice RAPN surgeon's performance with an observed 170% fewer Total Errors. GEARS showed poor reliability (Mean IRR = 0.44; range 0.0-0.8), for scoring RAPN surgical performance. The RAPN procedure metrics reliably distinguish Novice and Experienced surgeon performances. They further differentiated performance levels within a group with similar experiences. Reliable and valid metrics will underpin quality-assured novice RAPN surgical training.

An Ex Situ Cadaver Liver Training Model Continuously Pressurized to Simulate Specific Skills Involved in Laparoscopic Liver Resection: the Lap-Liver Trainer

BACKGROUND

Laparoscopic liver resection (LLR) requires delicate skills. The aim of the study was to develop a training model mimicking as much as possible intraoperative bleeding and bile leakage during LLR. We also assessed the educational value of the training model.

METHODS

The Lap-liver trainer (LLT) combined a continuously pressurized ex situ cadaver liver and a customized mannequin. The customized mannequin was designed by computer-aided design and manufactured by 3D printing. The left lateral sectionectomy (LLS) was chosen to assess the feasibility of a LLR with the LLT. Eighteen volunteers were recruited to perform LLS and to assess the educational value of the LLT using a Likert scale.

RESULTS

The customized mannequin consisted of a close laparoscopic training device based on a simplified reconstruction of the abdominal cavity in laparoscopic conditions. Ex situ cadaver livers were pressurized to simulate blood and bile supplies. Each expert surgeon (n = 3) performed two LLS. They were highly satisfied of simulation conditions (4.80 ± 0.45) and strongly recommended that the LLT should be incorporated into a teaching program (5.00 ± 0.0). Eight novice and 4 intermediate surgeons completed a teaching program and performed a LLS. Overall, the level of satisfaction was high (4.92 ± 0.29), and performing such a procedure under simulation conditions benefited their learning and clinical practice (4.92 ± 0.29).

CONCLUSIONS

The LLT could provide better opportunities for trainees to acquire and practice LLR skills in a more realistic environment and to improve their ability to deal with specific events related to LLR.

Simulation-based skills training: a qualitative interview study exploring surgical trainees' experience of stress

INTRODUCTION

Stress can affect the ability to acquire technical skills. Simulation-based training (SBT) courses allow surgical trainees to train their technical skills away from stressful clinical environments. Trainees' subjective experiences of stress during SBT courses on laparoscopic surgery remains understudied. Here, we explored the subjective stress experiences of surgical trainees during mandatory laparoscopic SBT courses. We aimed to obtain a broader understanding of which factors of the simulation training the trainees perceived as eliciting stress.

METHODS

A qualitative study with semistructured individual interviews was undertaken to explore trainees' subjective experiences of stress. Twenty surgical trainees participated while attending courses at a national training center for advanced laparoscopic surgery. Questions explored trainees' stress experiences during the SBT courses with a focus on perceived stressors related to laparoscopic simulation training on two box-trainers and one virtual reality simulator. Interview data were analyzed using inductive, qualitative content analysis methods to identify codes, categories, and themes.

RESULTS

Findings indicated that trainees have a variety of stress experiences during laparoscopic SBT. Three main themes were identified to be related to stress experiences: simulation task requirements, psychomotor skill levels and internal pressures, with subcategories such as task difficulty and time requirements, unrealistic haptic feedback and realism of graphics, inconsistent and poor technical performance, and self-imposed pressures and socio-evaluative threats.

CONCLUSIONS

Insights into surgical trainees' experience of stress during laparoscopic SBT courses showed that some stress experiences were directly related to simulation training, while others were of psychological nature. The technical and efficiency requirements of simulation tasks elicited stress experiences among trainees with less laparoscopic experience and lower levels of psychomotor skills. Self-imposed pressures played an integral part in how trainees mobilized and performed during the courses, suggesting that levels of stress might enhance laparoscopic simulation performance. For course facilitators aiming at optimizing future laparoscopic SBT courses, attending to the realism, providing clarity about learning objectives, and having awareness of individual differences among trainees' technical level when designing the simulation tasks, would be beneficial. Equally important to the laparoscopic SBT is to create a psychological safe learning space in order to reduce the internal pressures of trainees.

A neurotechnological aid for semi-autonomous suction in robotic-assisted surgery

Adoption of robotic-assisted surgery has steadily increased as it improves the surgeon’s dexterity and visualization. Despite these advantages, the success of a robotic procedure is highly dependent on the availability of a proficient surgical assistant that can collaborate with the surgeon. With the introduction of novel medical devices, the surgeon has taken over some of the surgical assistant’s tasks to increase their independence. This, however, has also resulted in surgeons experiencing higher levels of cognitive demands that can lead to reduced performance. In this work, we proposed a neurotechnology-based semi-autonomous assistant to release the main surgeon of the additional cognitive demands of a critical support task: blood suction. To create a more synergistic collaboration between the surgeon and the robotic assistant, a real-time cognitive workload assessment system based on EEG signals and eye-tracking was introduced. A computational experiment demonstrates that cognitive workload can be effectively detected with an 80% accuracy. Then, we show how the surgical performance can be improved by using the neurotechnological autonomous assistant as a close feedback loop to prevent states of high cognitive demands. Our findings highlight the potential of utilizing real-time cognitive workload assessments to improve the collaboration between an autonomous algorithm and the surgeon.

The burden of performing minimal access surgery: ergonomics survey results from 462 surgeons across Germany, the UK and the USA

This international study aimed to understand, from the perspective of surgeons, their experience of performing minimal access surgery (MAS), to explore causes of discomfort while operating and the impact of poor ergonomics on surgeon welfare and career longevity across different specialties and techniques. A quantitative online survey was conducted in Germany, the UK and the USA from March to April 2019. The survey comprised 17 questions across four categories: demographics, intraoperative discomfort, effects on performance and anticipated consequences. In total, 462 surgeons completed the survey. Overall, 402 (87.0%) surgeons reported experiencing discomfort while operating at least ‘sometimes’. The peak professional performance age was perceived to be 45–49 years by 30.7% of surgeons, 50–54 by 26.4% and older than 55 by 10.1%. 86 (18.6%) surgeons felt it likely they would consider early retirement, of whom 83 were experiencing discomfort. Our findings highlight the continued unmet needs of surgeons performing MAS, with the overwhelming majority experiencing discomfort, frequently in the back, neck and shoulders, and many likely to consider early retirement consequently. Innovative solutions are needed to alleviate this physical burden and, in turn, prevent economic and societal impacts on healthcare systems resulting from MAS limiting surgeon longevity.

The role of virtual reality simulation in surgical training in the light of COVID-19 pandemic: Visual spatial ability as a predictor for improved surgical performance: a randomized trial

INTRODUCTION

Due to the current COVID-19 pandemic, surgical training has become increasingly challenging due to required social distancing. Therefore, the use of virtual reality (VR)-simulation could be a helpful tool for imparting surgical skills, especially in minimally invasive environments. Visual spatial ability (VSA) might influence the learning curve for laparoscopic surgical skills. However, little is known about the influence of VSA for surgical novices on VR-simulator training regarding the complexity of different tasks over a long-term training period. Our study evaluated prior VSA and VSA development in surgical trainees during VR-simulator training, and its influence on surgical performance in simulator training.

METHODS

In our single-center prospective two-arm randomized trial, VSA was measured with a tube figure test before curriculum training. After 1:1 randomization, the training group (TG) participated in the entire curriculum training consisting of 48 different VR-simulator tasks with varying difficulty over a continuous nine-day training session. The control group (CG) performed two of these tasks on day 1 and 9. Correlation and regression analyses were used to assess the influence of VSA on VR-related surgical skills and to measure procedural abilities.

RESULTS

Sixty students (33 women) were included. Significant improvements in the TG in surgical performance and faster completion times were observed from days 1 to 9 for the scope orientation 30° right-handed (SOR), and cholecystectomy dissection tasks after the structured 9-day training program. After training, the TG with pre-existing low VSA scores achieved performance levels similar to those with pre-existing high VSA scores for the two VR simulator tasks. Significant correlations between VSA and surgical performance on complex laparoscopic camera navigation SOR tasks were found before training.

CONCLUSIONS

Our study revealed that that all trainees improved their surgical skills irrespective of previous VSA during structured VR simulator training. An increase in VSA resulted in improvements in surgical performance and training progress, which was more distinct in complex simulator tasks. Further, we demonstrated a positive relationship between VSA and surgical performance of the TG, especially at the beginning of training. Our results identified pre-existing levels of VSA as a predictor of surgical performance.

Camera realignment imposes a cost on laparoscopic performance

There is an unresolved question about whether realigned visual feedback is beneficial or costly to laparoscopic task performance. We provide evidence that camera realignment imposes a reliable cost on performance across both naive controls and experienced surgeons. This finding clarifies an important ongoing discussion in the literature about the effects of camera realignment, which could inform the strategies that laparoscopic surgeons use in the operating room.

The Artisential® Articulated Laparoscopic Forceps: A Dry Lab Study to Examine Dexterity and Learning Effects in Operators with Different Levels of Laparoscopic Experience

PURPOSE

The advent of robotic surgery has highlighted the advantages of articulation. This dry-lab study examined the dexterity and learning effect of a new articulated laparoscopic instrument: the ArtiSential® forceps (LIVSMED, Seongnam, Republic of Korea).

METHODS

A peg board task was designed. Three groups of volunteers with varying levels of laparoscopic expertise were organized to perform the task: expert, intermediate and novice. The participants performed the task using articulated and straight instruments, once before a 30-min training session and once afterwards. The times required to perform the task were recorded. The performances were analyzed and compared between the groups as well as between the straight and articulated instruments.

RESULTS

The experts were significantly faster than the novices with both instruments before the 30-min training session (p = 0.0317 for each instrument). No significant time difference was found among the three groups after the 30-min training session. The decrease in the time required to perform the peg-transfer task with the articulated instrument was significantly greater in the novice and intermediate groups (p = 0.0159 for each group). No significant difference in time reduction was observed between the groups with the straight instrument. Regardless of the user, the articulated device was associated with faster task performance than the straight device after 8 hours of training (p = 0.0039).

CONCLUSION

The ArtiSential® articulated device can improve dexterity. A significantly greater learning effect was observed in the novice and intermediate groups in comparison with experts. A plateau in the learning curve was observed after a few hours of training.

Application of multidirectional stitching technology in a laparoscopic suturing instructional program: a randomized controlled trial

BACKGROUND

Surgeon suturing technology plays a pivotal role in patient recovery after laparoscopic surgery. Intracorporal suturing and knot tying in minimally invasive surgery are particularly challenging and represent a key skill for advanced procedures. In this study, we compared the application of multidirectional stitching technology with application of the traditional method in a laparoscopic suturing instructional program.

METHODS

We selected forty residents within two years of graduation to assess the specialized teaching of laparoscopic suturing with laparoscopic simulators. The forty students were randomly divided into two groups, a control group and an experimental group, with twenty students in each group. The control group was scheduled to learn the traditional suture method, and the experimental group applied multidirectional stitching technology. The grades for suturing time, thread length, accuracy of needle entry, stability of the knot, tissue integrity, and tightness of the tissue before and after the training program were calculated.

RESULTS

There was no significant difference between the two groups before the learning intervention. After the program, both groups significantly improved in each subject. There were significant differences between the control group and the experimental group in suture time (P = 0.001), accuracy of needle entry and exit (P = 0.035), and whether the suture tissue had cracks (P = 0.030). However, the two groups showed non-significant differences in thread length (P = 0.093), stablity of the knot (P = 0.241), or tightness of the tissue (P = 0.367).

CONCLUSIONS

Multidirectional stitching technology improves the efficiency and effectiveness of traditional laparoscopic suture instructional programs. It might be a practicable, novel training method for acquiring proficiency in manual laparoscopic skills in a training setting.

Use of a Low-Cost Portable 3D Virtual Reality Gesture-Mediated Simulator for Training and Learning Basic Psychomotor Skills in Minimally Invasive Surgery: Development and Content Validity Study

Background

Simulation in virtual environments has become a new paradigm for surgeon training in minimally invasive surgery (MIS). However, this technology is expensive and difficult to access.

Objective

This study aims first to describe the development of a new gesture-based simulator for learning skills in MIS and, second, to establish its fidelity to the criterion and sources of content-related validity evidence.

Methods

For the development of the gesture-mediated simulator for MIS using virtual reality (SIMISGEST-VR), a design-based research (DBR) paradigm was adopted. For the second objective, 30 participants completed a questionnaire, with responses scored on a 5-point Likert scale. A literature review on the validity of the MIS training-VR (MIST-VR) was conducted. The study of fidelity to the criterion was rated using a 10-item questionnaire, while the sources of content-related validity evidence were assessed using 10 questions about the simulator training capacity and 6 questions about MIS tasks, and an iterative process of instrument pilot testing was performed.

Results

A good enough prototype of a gesture-based simulator was developed with metrics and feedback for learning psychomotor skills in MIS. As per the survey conducted to assess the fidelity to the criterion, all 30 participants felt that most aspects of the simulator were adequately realistic and that it could be used as a tool for teaching basic psychomotor skills in laparoscopic surgery (Likert score: 4.07-4.73). The sources of content-related validity evidence showed that this study’s simulator is a reliable training tool and that the exercises enable learning of the basic psychomotor skills required in MIS (Likert score: 4.28-4.67).

Conclusions

The development of gesture-based 3D virtual environments for training and learning basic psychomotor skills in MIS opens up a new approach to low-cost, portable simulation that allows ubiquitous learning and preoperative warm-up. Fidelity to the criterion was duly evaluated, which allowed a good enough prototype to be achieved. Content-related validity evidence for SIMISGEST-VR was also obtained.

A new platform for laparoscopic training: initial evaluation of the ex-vivo live multivisceral training device

BACKGROUND

Various training models have been developed for laparoscopic training. Inanimate models including cadavers, ex-vivo simulator, and virtual reality (VR), are less realistic and often fail to display specific events such as bleeding, bile leakage, etc. Animal models provide more realistic experience, but constraints like cost involved, anesthetic requirement, and ethical approval have limited its application. We have designed a new training ex-vivo simulator-Smagister to address these issues.

METHODS

The Smagister consists of a normothermic machine perfusion platform, multivisceral organ of porcine abdominal cavity (liver, gallbladder, pancreas, stomach, intestine, kidney, uterus, bladders, etc.), high-definition display, and software system. Blood gas analysis and number of peristalsis per hour were recorded. A questionnaire was used to subjectively assess vitality of the organ cluster every hour. Three laparoscopic procedures including cholecystectomy (LC), enterotomy closure (LEC) and hepatectomy (LLR) were performed on Smagister, with demonstration of specific events for each procedure. Six experts compared the procedures with actual surgery in terms of feasibility to complete procedures and demonstration of complications.

RESULTS

The fluctuation of perfusate glucose (6.1-8.2 mmol/L) and lactate (5.82-6.55 mmol/L) suggested metabolic function of the multivisceral organs. The mean number of peristalsis was 2.2/min. The simulated surgical view and anatomic structures closely resembled actual surgery during continuous perfusion (3.5 ± 1.0, 3.8 ± 0.8, respectively). The evaluation scores of haptic feedbacks were 3.8 ± 0.8, resembling live tissue handling. LC, LEC, and LLR were performed well on the Smagister, with clear display of the specific events. All six experts considered Smagister as a suitable training modality for both basic and advanced laparoscopic surgery.

CONCLUSION

The amalgamation of live animal model and ex-vivo simulation in Smagister centralizes the virtue of both modalities, expands the training field, and provides high-fidelity laparoscopic training for both novice and senior surgeons.

Construct validity of eoSim - a low-cost and portable laparoscopic simulator

Purpose: To examine the construct validity of the low-cost, portable laparoscopic simulator eoSim using motion analysis.Material and methods: Novice and experienced surgeons (≤ 100 and >100 laparoscopic procedures performed, respectively) completed four tasks on the eoSim using the SurgTrac software: intracorporeal suture and tie, tube ligation, peg capping and precision cutting. The following metrics were recorded: Time to complete task, distance traveled, handedness (left- versus right hand use), time off-screen, distance between instrument tips, speed, acceleration and motion smoothness.Results: Compared to novices (n = 22), experienced surgeons (n = 14) completed tasks in less time (p ≤ .025), except when performing peg capping (p = .052). On all tasks, they also scored lower on the distance metric (p ≤ .001). Differences in handedness (left hand compared between groups, right hand compared between groups) were found to be significant for three tasks (p ≤ .025). In general, the experienced group made greater use of their left hand than the novice group.Conclusion: The eoSim can differentiate between experienced and novice surgeons on the tasks intracorporeal suture and tie, tube ligation and precision cutting, thus providing a convenient method for surgical departments to implement testing of their surgeons' basic laparoscopic skills.

Creating 3D models from Radiologic Images for Virtual Reality Medical Education Modules

Virtual Reality (VR) is a powerful tool that has increasingly being used by medical field in recent years. It has been mainly used surgical training in particular laparoscopic procedures. VR can be used for the teaching of anatomy. The aim of the study is to show application of transforming 2D radiologic images into 3D model by using thresholding and segmentation and import into VR interface at an affordable cost. Four anatomy modules are created with inputs to control the rotational and translational movement of 3D models in the virtual space. These movements allow users to explore 3D models by using head tilt and gaze input. 3D models of the Circle of Willis, Vertebral Aneurysm, Spine, and Skull are rendered in the user's field of view at runtime. VR is constructed to have many potentials uses in radiology education. Visualization of 3D anatomic structures in a virtual environment give another tool for teaching to students and patients about anatomy of the body. Four anatomy modules described here demonstrate example user interaction patterns best suited for viewing contexts. Instead viewing stacked 2D images or 3D models confined to desktop applications, virtual reality increases user interactivity of education. An intuitive understanding of anatomic structures in 3D space enhances the learning experience for medical students, residents, and patients we are treating.

Novel laparoscopic training system with continuously perfused ex-vivo porcine liver for hepatobiliary surgery

OBJECTIVE

To introduce a novel laparoscopic training system with a continuously perfused ex-vivo porcine liver for hepatobiliary surgery.

BACKGROUND

Existing models for laparoscopic training, such as box trainers and virtual reality simulators, often fail to provide holistic training and real haptic feedback. We have formulated a new training system that addresses these problems.

METHODS

Real-Liver Laptrainer consists of a porcine liver, customized mannequin, ex-vivo machine perfusion system, and monitoring software. We made a detailed comparison of Real-Liver Laptrainer with the LapSim virtual reality simulator and the FLS Trainer Box systems. Five laparoscopic surgeons assessed the new system on multiple features. We assessed the performances of 43 trainees who used the new system to perform laparoscopic cholecystectomy (LC) three times.

RESULTS

Real-Liver Laptrainer offered more functions and better tactile feedback than the FLS or LapSim system. All five surgeons graded the quality of the new system as realistic. The utility of the system for training was scored as 3.6 ± 1.1 on a scale of 1-5. Between the first and third attempts, the number of successfully performed LCs increased (9 vs 14 vs 23; P = .011), while the numbers of liver damage incidents (25 vs. 21 vs. 18, P = .303) and gallbladder perforations decreased (17 vs. 12 vs. 9, P = .163). The mean LC operation time significantly decreased (63 vs. 50 vs. 44, P < .0001).

CONCLUSION

Real-Liver Laptrainer is a feasible, stable, and practical training model that has potential for improving the laparoscopic skills of surgeons.

Development of stereo endoscope system with its innovative master interface for continuous surgical operation

Background

Although robotic laparoscopic surgery has various benefits when compared with conventional open surgery and minimally invasive surgery, it also has issues to overcome and one of the issues is the discontinuous surgical flow that occurs whenever control is swapped between the endoscope system and the operating robot arm system. This can lead to problems such as collision between surgical instruments, injury to patients, and increased operation time. To achieve continuous surgical operation, a wireless controllable stereo endoscope system is proposed which enables the simultaneous control of the operating robot arm system and the endoscope system.

Methods

The proposed system consists of two improved novel master interfaces (iNMIs), a four-degrees of freedom (4-DOFs) endoscope control system (ECS), and a simple three-dimensional (3D) endoscope. In order to simultaneously control the proposed system and patient side manipulators of da Vinci research kit (dVRK), the iNMIs are installed to the master tool manipulators of dVRK system. The 4-DOFs ECS consists of four servo motors and employs a two-parallel link structure to provide translational and fulcrum point motion to the simple 3D endoscope. The images acquired by the endoscope undergo stereo calibration and rectification to provide a clear 3D vision to the surgeon as available in clinically used da Vinci surgical robot systems. Tests designed to verify the accuracy, data transfer time, and power consumption of the iNMIs were performed. The workspace was calculated to estimate clinical applicability and a modified peg transfer task was conducted with three novice volunteers.

Results

The iNMIs operated for 317 min and moved in accordance with the surgeon’s desire with a mean latency of 5 ms. The workspace was calculated to be 20378.3 cm³, which exceeds the reference workspace of 549.5 cm³. The novice volunteers were able to successfully execute the modified peg transfer task designed to evaluate the proposed system’s overall performance.

Conclusions

The experimental results verify that the proposed 3D endoscope system enables continuous surgical flow. The workspace is suitable for the performance of numerous types of surgeries. Therefore, the proposed system is expected to provide much higher safety and efficacy for current surgical robot systems.

Negating the fulcrum effect in manual laparoscopic surgery: Investigating skill acquisition with a haptic simulator

BACKGROUND

Manual laparoscopic surgery requires extensive training and familiarization. It has been suggested that motion inversion caused by the 'fulcrum effect' is key to motor challenges. We investigate the potential of a conceptual semi-robotic handheld tool that negates natural inversion.

METHODS

A custom laparoscopic simulator with haptic feedback was developed to allow interactive evaluation of the conceptual tool via virtual prototyping, prior to fabricating a physical prototype. Two groups of eight participants each used either the conceptual or a regular virtual tool over a ten week study to complete two abstract tasks of motor control and force regulation.

RESULTS

Statistically significant higher rates of skill improvement were demonstrated with the conceptual tool for motion efficiency, task completion time and error reduction. Force regulation increased for both groups but without significant differences.

CONCLUSIONS

The results indicate potential for fulcrum-negating hand tools in reducing the time needed to acquire motor skills.

A computerised test of perceptual ability for learning endoscopic and laparoscopic surgery and other image guided procedures: Score norms for PicSOr

BACKGROUND

The aptitude to infer the shape of 3-D structures, such as internal organs from 2-D monitor displays, in image guided endoscopic and laparoscopic procedures varies. We sought both to validate a computer-generated task Pictorial Surface Orientation (PicSOr), which assesses this aptitude, and to identify norm referenced scores.

METHODS

400 subjects (339 surgeons and 61 controls) completed the PicSOr test. 50 subjects completed it again one year afterwards.

RESULTS

Complete data was available on 396 of 400 subjects (99%). PicSOr demonstrated high test and re-test reliability (r = 0.807, p < 0.000). Surgeons performed better than controls' (surgeons = 0.874 V controls = 0.747, p < 0.000). Some surgeons (n = 22-5.5%) performed atypically on the test.

CONCLUSIONS

PicSOr has population distribution scores that are negatively skewed. PicSOr quantitatively characterises an aptitude strongly correlated to the learning and performance of image guided medical tasks. Most can do the PicSOr task almost perfectly, but a substantial minority do so atypically, and this is probably relevant to learning and performing endoscopic tasks.

Achieving Interface and Environment Fidelity in the Virtual Basic Laparoscopic Surgical Trainer

Virtual reality trainers are educational tools with great potential for laparoscopic surgery. They can provide basic skills training in a controlled environment and free of risks for patients. They can also offer objective performance assessment without the need for proctors. However, designing effective user interfaces that allow the acquisition of the appropriate technical skills on these systems remains a challenge. This paper aims to examine a process for achieving interface and environment fidelity during the development of the Virtual Basic Laparoscopic Surgical Trainer (VBLaST). Two iterations of the design process were conducted and evaluated. For that purpose, a total of 42 subjects participated in two experimental studies in which two versions of the VBLaST were compared to the accepted standard in the surgical community for training and assessing basic laparoscopic skills in North America, the FLS box-trainer. Participants performed 10 trials of the peg transfer task on each trainer. The assessment of task performance was based on the validated FLS scoring method. Moreover, a subjective evaluation questionnaire was used to assess the fidelity aspects of the VBLaST relative to the FLS trainer. Finally, a focus group session with expert surgeons was conducted as a comparative situated evaluation after the first design iteration. This session aimed to assess the fidelity aspects of the early VBLaST prototype as compared to the FLS trainer. The results indicate that user performance on the earlier version of the VBLaST resulting from the first design iteration was significantly lower than the performance on the standard FLS box-trainer. The comparative situated evaluation with domain experts permitted us to identify some issues related to the visual, haptic and interface fidelity on this early prototype. Results of the second experiment indicate that the performance on the second generation VBLaST was significantly improved as compared to the first generation and not significantly different from that of the standard FLS box-trainer. Furthermore, the subjects rated the fidelity features of the modified VBLaST version higher than the early version. These findings demonstrate the value of the comparative situated evaluation sessions entailing hands on reflection by domain experts to achieve the environment and interface fidelity and training objectives when designing a virtual reality laparoscopic trainer. This suggests that this method could be used successfully in the future to enhance the value of VR systems as an alternative to physical trainers for laparoscopic surgery skills. Some recommendations on how to use this method to achieve the environment and interface fidelity of a VR laparoscopic surgical trainer are identified.

Laparoscopic training model using fresh human cadavers without the establishment of penumoperitoneum

BACKGROUND:

Laparoscopy is a well-established alternative to open surgery for treating many diseases. Although laparoscopy has many advantages, it is also associated with disadvantages, such as slow learning curves and prolonged operation time. Fresh frozen cadavers may be an interesting resource for laparoscopic training, and many institutions have access to cadavers. One of the main obstacles for the use of cadavers as a training model is the difficulty in introducing a sufficient pneumoperitoneum to distend the abdominal wall and provide a proper working space. The purpose of this study was to describe a fresh human cadaver model for laparoscopic training without requiring a pneumoperitoneum.

MATERIALS AND METHODS AND RESULTS:

A fake abdominal wall device was developed to allow for laparoscopic training without requiring a pneumoperitoneum in cadavers. The device consists of a table-mounted retractor, two rail clamps, two independent frame arms, two adjustable handle and rotating features, and two frames of the abdominal wall. A handycam is fixed over a frame arm, positioned and connected through a USB connection to a television and dissector; scissors and other laparoscopic materials are positioned inside trocars. The laparoscopic procedure is thus simulated.

CONCLUSION:

Cadavers offer a very promising and useful model for laparoscopic training. We developed a fake abdominal wall device that solves the limitation of space when performing surgery on cadavers and removes the need to acquire more costly laparoscopic equipment. This model is easily accessible at institutions in developing countries, making it one of the most promising tools for teaching laparoscopy.

Robust Hand Motion Tracking through Data Fusion of 5DT Data Glove and Nimble VR Kinect Camera Measurements

Vision based interfaces for human computer interaction have gained increasing attention over the past decade. This study presents a data fusion approach of the Nimble VR vision based system, using the Kinect camera, with the contact based 5DT Data Glove. Data fusion was achieved through a Kalman filter. The Nimble VR and filter output were compared using measurements performed on (1) a wooden hand model placed in various static postures and orientations; and (2) three differently sized human hands during active finger flexions. Precision and accuracy of joint angle estimates as a function of hand posture and orientation were determined. Moreover, in light of possible self-occlusions of the fingers in the Kinect camera images, data completeness was assessed. Results showed that the integration of the Data Glove through the Kalman filter provided for the proximal interphalangeal (PIP) joints of the fingers a substantial improvement of 79% in precision, from 2.2 deg to 0.9 deg. Moreover, a moderate improvement of 31% in accuracy (being the mean angular deviation from the true joint angle) was established, from 24 deg to 17 deg. The metacarpophalangeal (MCP) joint was relatively unaffected by the Kalman filter. Moreover, the Data Glove increased data completeness, thus providing a substantial advantage over the sole use of the Nimble VR system.

A Proficiency-Based Progression Training Curriculum Coupled With a Model Simulator Results in the Acquisition of a Superior Arthroscopic Bankart Skill Set

PURPOSE

To determine the effectiveness of proficiency-based progression (PBP) training using simulation both compared with the same training without proficiency requirements and compared with a traditional resident course for learning to perform an arthroscopic Bankart repair (ABR).

METHODS

In a prospective, randomized, blinded study, 44 postgraduate year 4 or 5 orthopaedic residents from 21 Accreditation Council for Graduate Medical Education-approved US orthopaedic residency programs were randomly assigned to 1 of 3 skills training protocols for learning to perform an ABR: group A, traditional (routine Arthroscopy Association of North America Resident Course) (control, n = 14); group B, simulator (modified curriculum adding a shoulder model simulator) (n = 14); or group C, PBP (PBP plus the simulator) (n = 16). At the completion of training, all subjects performed a 3 suture anchor ABR on a cadaveric shoulder, which was videotaped and scored in blinded fashion with the use of previously validated metrics.

RESULTS

The PBP-trained group (group C) made 56% fewer objectively assessed errors than the traditionally trained group (group A) (P = .011) and 41% fewer than group B (P = .049) (both comparisons were statistically significant). The proficiency benchmark was achieved on the final repair by 68.7% of participants in group C compared with 36.7% in group B and 28.6% in group A. When compared with group A, group B participants were 1.4 times, group C participants were 5.5 times, and group C(PBP) participants (who met all intermediate proficiency benchmarks) were 7.5 times as likely to achieve the final proficiency benchmark.

CONCLUSIONS

A PBP training curriculum and protocol coupled with the use of a shoulder model simulator and previously validated metrics produces a superior arthroscopic Bankart skill set when compared with traditional and simulator-enhanced training methods.

CLINICAL RELEVANCE

Surgical training combining PBP and a simulator is efficient and effective. Patient safety could be improved if surgical trainees participated in PBP training using a simulator before treating surgical patients.

Predictive value of background experiences and visual spatial ability testing on laparoscopic baseline performance among residents entering postgraduate surgical training

BACKGROUND

Emerging evidence suggests that despite dedicated practice, not all surgical trainees have the ability to reach technical competency in minimally invasive techniques. While selecting residents that have the ability to reach technical competence is important, evidence to guide the incorporation of technical ability into selection processes is limited. Therefore, the purpose of the present study was to evaluate whether background experiences and 2D-3D visual spatial test results are predictive of baseline laparoscopic skill for the novice surgical trainee.

METHODS

First-year residents were studied. Demographic data and background surgical and non-surgical experiences were obtained using a questionnaire. Visual spatial ability was evaluated using the PicSOr, cube comparison (CC) and card rotation (CR) tests. Technical skill was assessed using the camera navigation (LCN) task and laparoscopic circle cut (LCC) task. Resident performance on these technical tasks was compared and correlated with the questionnaire and visual spatial findings.

RESULTS

Previous experience in observing laparoscopic procedures was associated with significantly better LCN performance, and experience in navigating the laparoscopic camera was associated with significantly better LCC task results. Residents who scored higher on the CC test demonstrated a more accurate LCN path length score (r s(PL) = -0.36, p = 0.03) and angle path (r s(AP) = -0.426, p = 0.01) score when completing the LCN task. No other significant correlations were found between the visual spatial tests (PicSOr, CC or CR) and LCC performance.

CONCLUSION

While identifying selection tests for incoming surgical trainees that predict technical skill performance is appealing, the surrogate markers evaluated correlate with specific metrics of surgical performance related to a single task but do not appear to reliably predict technical performance of different laparoscopic tasks. Predicting the acquisition of technical skills will require the development of a series of evidence-based tests that measure a number of innate abilities as well as their inherent interactions.

Laparoscopic suturing learning curve in an open versus closed box trainer

Background

The aim of this study was to examine the influence of training under direct vision prior to training with indirect vision on the learning curve of the laparoscopic suture task.

Methods

Novices were randomized in two groups. Group 1 performed three suturing tasks in a transparent laparoscopic box trainer under direct vision followed by three suturing tasks in a standard non-transparent laparoscopic box trainer equipped with a 0° laparoscope. Group 2 performed six suturing tasks in a standard laparoscopic box trainer. Performance time, motion analysis parameters (economy of movements) and interaction force parameters (tissue handling) were measured. Participants completed a questionnaire assessing: self-perceived dexterity before and after the training, their experienced frustration and the difficulty of the training.

Results

A total of 34 participants were included, one was excluded because of incomplete training. Group 1 used significantly less time to complete the total of six tasks (27 %). At the end of the training, there were no differences in motion or force parameters between the two groups. Group 2 rated their self-perceived dexterity after the training significantly lower than before the training and also reported significantly higher levels of frustration compared to group 1. Both groups rated the difficulty of the training similar.

Conclusion

Novices benefit from starting their training of difficult basic laparoscopic skills, e.g., suturing, in a transparent box trainer without camera. It takes less time to complete the tasks, and they get less frustrated by the training with the same results on their economy of movements and tissue handling skills.

Virtual reality simulators and training in laparoscopic surgery

Virtual reality simulators provide basic skills training without supervision in a controlled environment, free of pressure of operating on patients. Skills obtained through virtual reality simulation training can be transferred on the operating room. However, relative evidence is limited with data available only for basic surgical skills and for laparoscopic cholecystectomy. No data exist on the effect of virtual reality simulation on performance on advanced surgical procedures. Evidence suggests that performance on virtual reality simulators reliably distinguishes experienced from novice surgeons Limited available data suggest that independent approach on virtual reality simulation training is not different from proctored approach. The effect of virtual reality simulators training on acquisition of basic surgical skills does not seem to be different from the effect the physical simulators. Limited data exist on the effect of virtual reality simulation training on the acquisition of visual spatial perception and stress coping skills. Undoubtedly, virtual reality simulation training provides an alternative means of improving performance in laparoscopic surgery. However, future research efforts should focus on the effect of virtual reality simulation on performance in the context of advanced surgical procedure, on standardization of training, on the possibility of synergistic effect of virtual reality simulation training combined with mental training, on personalized training.

Influence of visual force feedback on tissue handling in minimally invasive surgery

Background

Force feedback might improve surgical performance during minimally invasive surgery. This study sought to determine whether training with force feedback shortened the tissue-handling learning curve, and examined the influence of real-time visual feedback compared with postprocessing feedback.

Methods

Medical students without experience of minimally invasive surgery were randomized into three groups: real-time force feedback, postprocessing force feedback and no force feedback (control). All performed eight suturing tasks consecutively, of which the first and eighth were the premeasurement and postmeasurement tasks respectively (no feedback). Depending on randomization, either form of feedback was given during the second to seventh task. Time, mean force non-zero and maximum force were measured with a force sensor. Results of the groups were compared with one-way ANOVA, and intragroup improvement using a paired-samples t test.

Results

A total of 72 students took part. Both intervention groups used significantly lower interaction forces than the control group during the knot-tying phase of the postmeasurement task and improved their interaction forces significantly during the knot-tying phase. The form of feedback did not influence its effectiveness.

Conclusion

The tissue-handling skills of medical students improved significantly when they were given force feedback of their performance. This effect was seen mainly during the knot-tying phase of the suturing task.

Laparoscopic liver resection using a rubber band retraction technique: usefulness and perioperative outcome in 100 consecutive cases

BACKGROUND

Although laparoscopic liver resection is increasingly performed worldwide, surgeons still face technical challenges because of the variety of procedures used according to tumor location. In the current study, we introduce a unique retraction method using an elastic rubber band and present its learning curve in addition to the perioperative outcomes of 100 consecutive patients.

METHODS

A series of 100 consecutive patients who underwent laparoscopic liver resection using a rubber band technique between August 2008 and June 2013 were analyzed retrospectively. All the study patients underwent the rubber band technique as a method to expose the parenchymal resection plane.

RESULTS

The study subjects consisted of 56 males and 44 females with a mean age of 56.7 ± 9.6 years. There were a total of four open conversions. There was no postoperative mortality. Eighty-five patients underwent minor resection, and 15 patients underwent major resection. Among the 85 patients who underwent a minor resection, 65 patients who had favorably located tumors were compared with the 20 patients who had unfavorably located tumors. A comparison of perioperative outcomes revealed a significant difference in operative time (197.3 ± 81.9 vs. 245.9 ± 116.8 min, P = 0.040) but no differences in any other parameters. There were three (4.6 %) and one (5 %) open conversions in the favorable and unfavorable tumor location group, respectively (P = 0.954). The postoperative complication rates were not statistically different between the two groups [4 (6.2 %) vs. 1 (5 %), P = 0.848]. In the learning curve analysis, operative time and blood loss for left lateral sectionectomy (n = 14) and left hepatectomy (n = 12) and minor limited resections for posterosuperior lesions (n = 20) reached a plateau after approximately ten cases.

CONCLUSION

The retraction technique describes here using an elastic rubber band is a useful approach that results in a safe laparoscopic liver resection. Moreover, this can be applied proficiently after a reasonable learning curve.

The investigation of laparoscopic instrument movement control and learning effect

Laparoscopic surgery avoids large incisions for intra-abdominal operations as required in conventional open surgery. Whereas the patient benefits from laparoscopic techniques, the surgeon encounters new difficulties that were not present during open surgery procedures. However, limited literature has been published in the essential movement characteristics such as magnification, amplitude, and angle. For this reason, the present study aims to investigate the essential movement characteristics of instrument manipulation via Fitts' task and to develop an instrument movement time predicting model. Ten right-handed subjects made discrete Fitts' pointing tasks using a laparoscopic trainer. The experimental results showed that there were significant differences between the three factors in movement time and in throughput. However, no significant differences were observed in the improvement rate for movement time and throughput between these three factors. As expected, the movement time was rather variable and affected markedly by direction to target. The conventional Fitts' law model was extended by incorporating a directional parameter into the model. The extended model was shown to better fit the data than the conventional model. These findings pointed to a design direction for the laparoscopic surgery training program, and the predictive model can be used to establish standards in the training procedure.

An ergonomic analysis of the effects of camera rotation on laparoscopic performance

BACKGROUND

Minimal access surgery is associated with increased risk of complications, particularly early in a surgeon's laparoscopic career. This is mostly due to loss of depth cues, degraded tactile feedback from surgical instrument, and the "fulcrum effect". Degraded and restricted image on the monitor makes camera orientation very important. The objective of this study is to investigate the effects of camera rotation on laparoscopic performance.

METHODS

In two separate studies 100 laparoscopic novices and 7 experienced laparoscopic surgeons ([300 laparoscopic procedures) were asked to perform a simple laparoscopic cutting task and tie intracorporeal square-knots (respectively) under 0, 15, 45, 90, and 180 camera rotation.

RESULTS

In study 1 camera rotation significantly degraded performance of laparoscopic novices (p\0.00001) and also increased their error rate (p\0.00001). In study 2 camera rotation significantly increased the length of time it took surgeons to tie an intracorporeal square-knot (p\0.00001) and the number of errors made (p\0.0001).

CONCLUSIONS

Unintentional camera rotation during surgery should be avoided to eliminate one potential source for errors.

Validation of a new box trainer-related tracking device: the TrEndo

Background

There is an increasing demand for structured objective ex vivo training and assessment of laparoscopic psychomotor skills prior to implementation of these skills in practice. The aim of this study was to establish the internal validity of the TrEndo, a motion-tracking device, for implementation on a laparoscopic box trainer.

Methods

Face validity and content validity were addressed through a structured questionnaire. To assess construct validity, participants were divided into an expert group and a novice group and performed two basic laparoscopic tasks. The TrEndo recorded five motion analysis parameters (MAPs) and time.

Results

Participants demonstrated a high regard for face and content validity. All recorded MAPs differed significantly between experts and novices after performing a square knot. Overall, the TrEndo correctly assigned group membership in 84.7 and 95.7% of cases based on two laparoscopic tasks.

Conclusion

Face, content, and construct validities of the TrEndo were established. The TrEndo holds real potential as a (home) training device.

Robotic liver resection: technique and results of 30 consecutive procedures

BACKGROUND

Robotic surgery can enhance a surgeon's laparoscopic skills through a magnified three-dimensional view and instruments with seven degrees of freedom compared to conventional laparoscopy.

METHODS

This study reviewed a single surgeon's experience of robotic liver resections in 30 consecutive patients, focusing on major hepatectomy. Clinicopathological characteristics and perioperative and short-term outcomes were analyzed.

RESULTS

The mean age of the patients was 52.4 years and 14 were male. There were 21 malignant tumors and 9 benign lesions. There were 6 right hepatectomies, 14 left hepatectomies, 4 left lateral sectionectomies, 2 segmentectomies, and 4 wedge resections. The average operating time for the right and left hepatectomies was 724 min (range 648-812) and 518 min (range 315-763), respectively. The average estimated blood loss in the right and left hepatectomies was 629 ml (range 100-1500) and 328 ml (range 150-900), respectively. Four patients (14.8%) received perioperative transfusion. There were two conversions to open surgery (one right hepatectomy and one left hepatectomy). The overall complication rate was 43.3% (grade I, 5; grade II, 2; grade III, 6; grade IV, 0) and 40% in 20 patients who underwent major hepatectomy. Among the six (20.0%) grade III complications, a liver resection-related complication (bile leakage) occurred in two patients. The mean length of hospital stay was 11.7 days (range 5-46). There was no recurrence in the 13 patients with hepatocellular carcinoma during the median follow-up of 11 months (range 5-29).

CONCLUSIONS

From our experience, robotic liver resection seems to be a feasible and safe procedure, even for major hepatectomy. Robotic surgery can be considered a new advanced option for minimally invasive liver surgery.

On the Persistence of Tool-Based Compatibility Effects

Using tools, such as simple levers, makes specific demands on the motor system. Two related performance decrements have been reported: The costs that arise when required tool movements and movements of the operating hand are spatially incompatible (hand-tool compatibility), and the costs that arise when relevant stimuli and tool movements are spatially incompatible (stimulus-tool compatibility). We performed two experiments to test the boundary conditions of both effects. Experiment 1 revealed a strong hand-tool compatibility effect despite visual occlusion of the hand and instructions to ignore hand movements. Experiment 2 revealed influences of stimulus-tool compatibility despite instructions to ignore the tool and to pay attention to the operating hand alone. These results suggest that lever movements of the type studied here become automatically represented and constrain motor performance.

Acquisition of fundamental laparoscopic skills: is a box really as good as a virtual reality trainer?

BACKGROUND

Laparoscopic surgery requires working in a three-dimensional environment with a two-dimensional view. Skills such as depth perception, hand to eye co-ordination and bimanual manipulation are crucial to its efficacy.

AIM

To compare the efficiency of training in laparoscopic skills on a VR simulator with a traditional box trainer.

METHOD

Twenty medical students were recruited. An initial training session on the relevant anatomy and steps of a laparoscopic cholecystectomy was given. Baseline skills were recorded using a pre-training laparoscopic cholecystectomy on the VR trainer. Parameters measured were: (1) total time taken (mins); (2) number of movements right and left instrument; (3) path length (cms) of right and left instrument was recorded. Ten students trained on a VR simulator, and ten on a box trainer, for three hours each. The box trainer group exercises were based on the Royal College of Surgeons core laparoscopic skills course, and the VR trainer exercises were based on the Simbionix LapMentor basic skills tasks. Following this both groups were reassessed by a laparoscopic cholecystectomy on the VR trainer.

RESULTS

Both groups showed improvement in all measured parameters. A student T-test at 95% confidence interval showed no statistically significant difference between the two groups pre and post training.

CONCLUSION

Both the VR and box trainer are effective in the acquisition of laparoscopic skills.

Action representations in perception, motor control and learning: implications for medical education

OBJECTIVES

the motor behaviours or 'actions' that provide the basis for precision limb control, including the performance of complex medical procedures, are represented at different levels in the central nervous system. This review focuses on how these representations influence the way people perceive, execute and learn goal-directed movements.

PERCEPTION AND ATTENTION

the neural processes associated with paying attention to an object are part and particle of the same processes engaged to physically interact with that object. The automatic way in which specific actions are engaged makes it important that we structure perceptual motor environments in a manner that facilitates goal actions and minimises the likelihood of unwanted actions.

MOTOR CONTROL

most actions are organised to optimise speed, accuracy and energy expenditure while avoiding worst-case outcomes. To achieve a good outcome on movements, the performer must have the opportunity to experiment with the way specific actions are executed. Early in the discovery process, errors are necessary if the performer is to determine his or her performance boundaries. motor learning: as learning progresses, representations of action become predictive. For example, if rapid corrective processes are to operate, the performer needs to anticipate sensorimotor consequences of movement. Thus, practice should be specific to the conditions under which actions are performed, and the performer. Although nothing can replace physical practice, complex representations of action can develop by observing both expert performers and learners. In many cases, practice scenarios that include both physical practice and observations of other learners can be the most efficient use of time and resources.

CONCLUSIONS

although most of the experiments reviewed here involved laboratory tasks such as rapid aiming and movement sequencing, the majority of the principles apply to motor control and learning in more complex situations. Thus, they should be considered when developing methods to train medical personnel to perform perceptual motor procedures with precision.

Bimanual interference with compatible and incompatible tool transformations

The present study investigates bimanual interference in a tool-use task, in which two target locations had to be touched concurrently with two tools, one for each hand. Target locations were either in the same, or in different directions for the two hands. Furthermore, the tools implemented either a compatible or an incompatible relationship between the direction of target locations and the direction of associated bodily movements. Results indicated bimanual interference when the tools had to be moved to targets in different directions. Furthermore, this interference was much more pronounced when the tools required body movements that were spatially incompatible to the cued target locations as compared to when they were compatible. These results show that incompatible relationships between target directions and bodily movement directions can aggravate bimanual interference in tool use.