Randomly alternating image presentation during laparoscopic training leads to faster automation to the "fulcrum effect"

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.

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.

Robotic cholecystectomy using Revo-i Model MSR-5000, the newly developed Korean robotic surgical system: a preclinical study

BACKGROUND

Laparoscopic surgery has become the standard option for gastrointestinal surgeries. However, laparoscopic procedures require extended training times and are difficult for inexperienced surgeons. Robot-assisted laparoscopic surgery facilitates easy adaptation of laparoscopic procedures, but robotic surgical systems are expensive. In addition, their cost has remained high because there is currently only one manufacturer of commercially available systems. Recently, a new Korean robotic surgical system, Revo-i, has been developed. The aim of this study was to evaluate the feasibility and safety of Revo-i by performing robotic cholecystectomy in a porcine model.

METHODS

After approval by the Institutional Animal Care and Use Committee of Yonsei University Health System, cholecystectomy was performed in four pigs using the Revo-i robotic surgical system. Operative time and perioperative complications were recorded, and all animals were observed for postoperative complications for 2 weeks after surgery RESULTS: Robotic cholecystectomy was completed successfully and without gallbladder perforation in all cases. The mean operative time was 78 ± 12 min, the mean docking time was 4.5 ± 2.52 min, and the mean console time was 49.8 ± 14.17 min. There were no perioperative complications, and none of the animal used for the in vivo models exhibited abnormal behavior during the postoperative observation period.

CONCLUSIONS

These preliminary results verify the safety and efficacy of robotic cholecystectomy using the Revo-i robotic surgical system. Human trials are slated to begin accordingly.

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.

Modelling dynamic fronto-parietal behaviour during minimally invasive surgery--a Markovian trip distribution approach

Learning to perform Minimally Invasive Surgery (MIS) requires considerable attention, concentration and spatial ability. Theoretically, this leads to activation in executive control (prefrontal) and visuospatial (parietal) centres of the brain. A novel approach is presented in this paper for analysing the flow of fronto-parietal haemodynamic behaviour and the associated variability between subjects. Serially acquired functional Near Infrared Spectroscopy (fNIRS) data from fourteen laparoscopic novices at different stages of learning is projected into a low-dimensional 'geospace', where sequentially acquired data is mapped to different locations. A trip distribution matrix based on consecutive directed trips between locations in the geospace reveals confluent fronto-parietal haemodynamic changes and a gravity model is applied to populate this matrix. To model global convergence in haemodynamic behaviour, a Markov chain is constructed and by comparing sequential haemodynamic distributions to the Markov's stationary distribution, inter-subject variability in learning an MIS task can be identified.

Surgical simulation: a systematic review

OBJECTIVE

To evaluate the effectiveness of surgical simulation compared with other methods of surgical training.

SUMMARY BACKGROUND DATA

Surgical simulation (with or without computers) is attractive because it avoids the use of patients for skills practice and provides relevant technical training for trainees before they operate on humans.

METHODS

Studies were identified through searches of MEDLINE, EMBASE, the Cochrane Library, and other databases until April 2005. Included studies must have been randomized controlled trials (RCTs) assessing any training technique using at least some elements of surgical simulation, which reported measures of surgical task performance.

RESULTS

Thirty RCTs with 760 participants were able to be included, although the quality of the RCTs was often poor. Computer simulation generally showed better results than no training at all (and than physical trainer/model training in one RCT), but was not convincingly superior to standard training (such as surgical drills) or video simulation (particularly when assessed by operative performance). Video simulation did not show consistently better results than groups with no training at all, and there were not enough data to determine if video simulation was better than standard training or the use of models. Model simulation may have been better than standard training, and cadaver training may have been better than model training.

CONCLUSIONS

While there may be compelling reasons to reduce reliance on patients, cadavers, and animals for surgical training, none of the methods of simulated training has yet been shown to be better than other forms of surgical training.

Advantages of advanced laparoscopic systems

BACKGROUND

Conventional laparoscopy offers great benefits to our patients, but suffers from major technical drawbacks. Advanced laparoscopic systems are being developed addressing some of these drawbacks.

METHODS

We performed a training-box based study, performing laparoscopic tasks using conventional laparoscopy and advanced laparoscopic systems in order to assess the influence of these technical drawbacks in order to predict where the biggest advantages of newly developed surgical systems can be expected.

RESULTS

The most significant technical drawbacks were two-dimensional vision, disturbed eye-hand target axis and (possibly to a lesser extent) the rigid instruments with a limited five degrees of freedom.

CONCLUSION

Major advances in advanced laparoscopy might only be expected using console-based robot-arm manipulated systems like the daVinci surgical system, or a combination of a high-quality 3-dimensional vision system, restoration of the eye-hand-target axis and the use of an advanced handheld instrument offering seven degrees of freedom such as the Radius surgical system.

HMM Assessment of Quality of Movement Trajectory in Laparoscopic Surgery

Laparoscopic surgery poses many different constraints to the operating surgeon, this has resulted in a slow uptake of advanced laparoscopic procedures. Traditional approaches to the assessment of surgical performance rely on prior classification of a cohort of surgeons' technical skills for validation, which may introduce subjective bias to the outcome. In this study, Hidden Markov Models (HMMs) are used to learn surgical maneuvers from 11 subjects with mixed abilities. By using the leave-one-out method, the HMMs are trained without prior clustering subjects into different skills levels, and the output likelihood indicates the similarity of a particular subject's motion trajectories to the group. The experimental results demonstrate the strength of the method in ranking the quality of trajectories of the subjects, highlighting its value in minimizing the subjective bias in skills assessment for minimally invasive surgery.

Cyber visual training as a new method for the mastery of endoscopic surgery

BACKGROUND

We devised a new method incorporating cyber visual training whereby novices in endoscopic surgery are instructed via repetition of a video-recorded procedure. We then conducted a study designed to investigate the impact of this cyber visual training on the mastery of intracorporeal knot-tying as an endoscopic technique.

METHODS

For the cyber visual training a 10-min video of the same procedure was replayed at normal, slow, and rapid speeds or presented in a series of still images. The training was undertaken by 36 medical students and 1st year trainee doctors who had had no experience of endoscopic surgery. They were divided into three groups, each of all received the same introductory lecture. Group A was only given training with the instructor for 15 min. Group B trained with the instructor for 15 min and was allowed self-training for 10 min. Group C viewed the cyber video beforehand and then underwent training with the instructor for 15 min. For all participants, the time required to complete a knot-tying task was measured and the level of endoscopic skill before and after the training was assessed using a virtual reality system the minimally Invasive Surgical Trainer-Virtual Reality (MIST-VR), in terms of the following three parameters: time, errors, and efficiency of hand movements. The Steel-Dwass test was used to evaluate the differences among the three groups in task performance.

RESULTS

Group C completed the knot-tying task faster than group A (p = 0.0375), but there were significant differences between groups A and B and groups B and C. There were no significant differences in the parameters assessed using the MIST-VR.

CONCLUSIONS

Our new concept of cyber visual training is effective for mastering the knot-tying technique. This type of training should be widely applicable to other procedures, such as dissection, clipping, and hemostasis.

Discriminative validity of the Minimally Invasive Surgical Trainer in Virtual Reality (MIST-VR) using criteria levels based on expert performance

BACKGROUND

Increasing constraints on the time and resources needed to train surgeons have led to a new emphasis on finding innovative ways to teach surgical skills outside the operating room. Virtual reality training has been proposed as a method to both instruct surgical students and evaluate the psychomotor components of minimally invasive surgery ex vivo.

METHODS

The performance of 100 laparoscopic novices was compared to that of 12 experienced (>50 minimally invasive procedures) and 12 inexperienced (<10 minimally invasive procedures) laparoscopic surgeons. The values of the experienced surgeons' performance were used as benchmark comparators (or criterion measures). Each subject completed six tasks on the Minimally Invasive Surgical Trainer-Virtual Reality (MIST-VR) three times. The outcome measures were time to complete the task, number of errors, economy of instrument movement, and economy of diathermy.

RESULTS

After three trials, the mean performance of the medical students approached that of the experienced surgeons. However, 7-27% of the scores of the students fell more than two SD below the mean scores of the experienced surgeons (the criterion level).

CONCLUSIONS

The MIST-VR system is capable of evaluating the psychomotor skills necessary in laparoscopic surgery and discriminating between experts and novices. Furthermore, although some novices improved their skills quickly, a subset had difficulty acquiring the psychomotor skills. The MIST-VR may be useful in identifying that subset of novices.

In-line image projection accelerates task performance in laparoscopic appendectomy

BACKGROUND

In laparoscopy, the monitor usually is placed at or above eye level across from the operating surgeon. Position of the endoscopic image at hand level has been shown in a laboratory model to facilitate task performance. The authors tested the hypothesis that in-line image projection reduced operating time for a standardized procedure.

METHODS

Children undergoing laparoscopic appendectomy were assigned randomly according to video image position: (1) at the top of the laparoscopy tower in front of the surgeon ("overhead") or (2) on a screen placed on the patient's abdomen ("in-line"). Operating time was recorded for each operation, and patients were stratified according to severity of appendicitis and training level of the operating surgeon. Statistical analysis was performed using Student's t, chi2 tests, and analysis of variance with post-hoc Fisher test (P <.05. significant).

RESULTS

One hundred eight children, aged 2 to 17 years, underwent a laparoscopic appendectomy during a 26-month period. Fifty-four were assigned to the in-line projection screen and 54 to the overhead monitor. Operating time was significantly shorter (P =.013) when in-line projection was used (46.8 +/- 10.2 v. 52.2 +/- 15.1 minutes with overhead monitor). By analysis of variance (ANOVA) the only factors that significantly affected operating time were use of in-line projection (P =.030), severity of appendicitis (P =.002), and training level of the operating surgeon (P =.047).

CONCLUSIONS

Placing the endoscopic image in the same field as the surgeon's hands decreases operating time by 10%, even for procedures that, like appendectomy, do not require complex suturing skills. This decrease in operating time occurs independently of the surgeon's level of proficiency or the degree of difficulty of the operation.

A comparison between randomly alternating imaging, normal laparoscopic imaging, and virtual reality training in laparoscopic psychomotor skill acquisition

OBJECTIVES

To evaluate virtual reality as a laparoscopic training device in helping surgeons to automate to the "fulcrum effect" by comparing it to time-matched training programs using randomly alternating images (ie, y-axis inverted and normal laparoscopic) and normal laparoscopic viewing conditions.

METHODS

Twenty-four participants (16 females and 8 males), were randomly assigned to minimally invasive surgery virtual reality (MIST VR), randomly alternating (between y-axis inverted and normal laparoscopic images), and normal laparoscopic imaging condition. Participants were requested to perform a 2-minute laparoscopic cutting task before and after training.

RESULTS

In the test trial participants who trained on the MIST VR performed significantly better than those in the normal laparoscopic and randomly alternating imaging conditions.

CONCLUSION

The results show that virtual reality training may provide faster skill acquisition with particular reference to automation of the fulcrum effect. MIST VR provides a new way of training laparoscopic psychomotor surgical skills.