Magdalena K. Chmarra

Force feedback and basic laparoscopic skills

BackgroundNot much is known about the exact role of force feedback in laparoscopy. This study aimed to determine whether force feedback influences movements of instruments during training in laparoscopic tasks and whether force feedback is required for training in basic laparoscopic force application tasks.MethodsA group of 19 gynecologic residents, randomly divided into two groups, performed three laparoscopic tasks in both the box trainer and the virtual reality (VR) trainer. The box-VR group began with the box trainer, whereas the VR-box group began with the VR trainer. The three selected tasks included different levels of force application. The box trainer provides natural force feedback, whereas the VR trainer does not provide force feedback. The performance of the two groups was compared with regard to time, path length, and depth perception.ResultsFor the tasks in which force plays hardly a role, no differences between box-VR group and the VR-box group were found. During a task in which force application (pulling and pushing forces) plays a role, the box-VR group outperformed VR-box group in the box trainer. Moreover, training with the box trainer had a positive effect on subsequent performance of the task with the VR trainer. This was not found the other way around. No differences were found between box-VR and the VR-box group in tasks not requiring force application.ConclusionForce feedback influences basic laparoscopic skills during tasks in which pulling and pushing forces are applied. For these tasks, the switch from the trainer without force feedback to the one with natural force feedback has a detrimental effect on performance. Therefore, training for tasks in which forces play an important role (e.g., stretching, grasping) should be done using systems with natural force feedback, whereas eye–hand coordination can be trained without force feedback.

Systems for tracking minimally invasive surgical instruments

Minimally invasive surgery (e.g. laparoscopy) requires special surgical skills, which should be objectively assessed. Several studies have shown that motion analysis is a valuable assessment tool of basic surgical skills in laparoscopy. However, to use motion analysis as the assessment tool, it is necessary to track and record the motions of laparoscopic instruments. This article describes the state of the art in research on tracking systems for laparoscopy. It gives an overview on existing systems, on how these systems work, their advantages, and their shortcomings. Although various approaches have been used, none of the tracking systems to date comes out as clearly superior. A great number of systems can be used in training environment only, most systems do not allow the use of real laparoscopic instruments, and only a small number of systems provide force feedback.

Objective classification of residents based on their psychomotor laparoscopic skills

BackgroundFrom the clinical point of view, it is important to recognize residents’ level of expertise with regard to basic psychomotor skills. For that reason, surgeons and surgical organizations (e.g., Acreditation Council for Graduate Medical Education, ACGME) are calling for assessment tools that credential residents as technically competent. Currently, no method is universally accepted or recommended for classifying residents as “experienced,” “intermediates,” or “novices” according to their technical abilities. This study introduces a classification method for recognizing residents’ level of experience in laparoscopic surgery based on psychomotor laparoscopic skills alone.MethodsFor this study, 10 experienced residents (>100 laparoscopic procedures performed), 10 intermediates (10–100 procedures performed), and 11 novices (no experience) performed four tasks in a box trainer. The movements of the laparoscopic instruments were recorded with the TrEndo tracking system and analyzed using six motion analysis parameters (MAPs). The MAPs of all participants were submitted to principal component analysis (PCA), a data reduction technique. The scores of the first principal components were used to perform linear discriminant analysis (LDA), a classification method. Performance of the LDA was examined using a leave-one-out cross-validation.ResultsOf 31 participants, 23 were classified correctly with the proposed method, with 7 categorized as experienced, 7 as intermediates, and 9 as novices.ConclusionsThe proposed method provides a means to classify residents objectively as experienced, intermediate, or novice surgeons according to their basic laparoscopic skills. Due to the simplicity and generalizability of the introduced classification method, it is easy to implement in existing trainers.

Fundamental aspects of learning minimally invasive surgical skills.

With the introduction of minimally invasive surgery (MIS) the necessity to develop training methods to learn skills outside the operating room (OR) became clear. Several training simulators have become commercially available. However, fundamental research into the requirements for effective and efficient training in MIS is still lacking. Yet in the literature several learning models have been described that may be used when designing the structure of a training program. While learning skills, three stages can be observed: cognitive, associative and autonomous. The learning cycle also includes different learning styles and, moreover, every trainee has his/her preferred learning style. Furthermore, training should be adapted to the level of behaviour: skill‐based, rule‐based or knowledge‐based. Training of complex skills should include multiple performance objectives, such as just‐in‐time supportive information and part‐task practice. Finally, motivation for training can be created by assessment. In conclusion, several theories on learning can be found in the literature. These theories may help in the development of effective training programs for training MIS skills outside the OR.

The influence of experience and camera holding on laparoscopic instrument movements measured with the TrEndo tracking system

BackgroundEye–hand coordination problems occur during laparoscopy. This study aimed to investigate the difference in instrument movements between the surgeon him- or herself holding the camera and an assistant holding the camera during performance of a laparoscopic task and to check whether experience of the surgeon plays a role in this issue.MethodsThe participants were divided into three groups: experts, residents, and novices. Each participant performed positioning tasks using the right (R) and left (L) hands. During these tasks, the camera was manipulated either by the participant (Cself) or by an assistant (Cassistant). Movements of instruments were recorded with the authors’ new TrEndo tracking system. The performance was analyzed using five kinematic parameters: time, path length, three-dimensional (3D) motion smoothness, 1D motion smoothness (along the axis), and depth perception.ResultsA total of 46 participants contributed. Three tests were performed: test 1-LCself, test 2-LCassistant, and test 3-RCassistant. In all the tests, the experts performed better than the residents and novices in terms of time, path length, and depth perception. The novices performed better in tests 1-LCself and 2-LCassistant than in test 3-RCassistant in terms of path length, 3D motion smoothness, and depth perception.ConclusionsLaparoscopic experience and the camera-holding factor influenced the performance of laparoscopic tasks on the simulator. Time, path length, and depth perception clearly discriminate between different levels of experience in laparoscopy, whereas 3D and 1D motion smoothness play a limited role. Novices experienced more difficulties when an assistant held the camera. Therefore, self-manipulation of the camera seems to improve novices’ eye–hand coordination.

Retracting and seeking movements during laparoscopic goal-oriented movements. Is the shortest path length optimal?

AimsMinimally invasive surgery (MIS) requires a high degree of eye–hand coordination from the surgeon. To facilitate the learning process, objective assessment systems based on analysis of the instruments’ motion are being developed. To investigate the influence of performance on motion characteristics, we examined goal-oriented movements in a box trainer. In general, goal-oriented movements consist of a retracting and a seeking phase, and are, however, not performed via the shortest path length. Therefore, we hypothesized that the shortest path is not an optimal concept in MIS.MethodsParticipants were divided into three groups (experts, residents, and novices). Each participant performed a number of one-hand positioning tasks in a box trainer. Movements of the instrument were recorded with the TrEndo tracking system. The movement from point A to B was divided into two phases: A-M (retracting) and M-B (seeking). Normalized path lengths (given in %) of the two phases were compared.ResultsThirty eight participants contributed. For the retracting phase, we found no significant difference between experts [median (range) %: 152 (129–178)], residents [164 (126–250)], and novices [168 (136–268)]. In the seeking phase, we find a significant difference (<0.001) between experts [180 (172–247)], residents [201 (163–287)], and novices [290 (244–469)]. Moreover, within each group, a significant difference between retracting and seeking phases was observed.ConclusionsGoal-oriented movements in MIS can be split into two phases: retracting and seeking. Novices are less effective than experts and residents in the seeking phase. Therefore, the seeking phase is characteristic of performance differences. Furthermore, the retracting phase is essential, because it improves safety by avoiding intermediate tissue contact. Therefore, the shortest path length, as presently used during the assessment of basic MIS skills, may be not a proper concept for analyzing optimal movements and, therefore, needs to be revised.

Relevance of Motion-Related Assessment Metrics in Laparoscopic Surgery

Introduction. Motion metrics have become an important source of information when addressing the assessment of surgical expertise. However, their direct relationship with the different surgical skills has not been fully explored. The purpose of this study is to investigate the relevance of motion-related metrics in the evaluation processes of basic psychomotor laparoscopic skills and their correlation with the different abilities sought to measure. Methods. A framework for task definition and metric analysis is proposed. An explorative survey was first conducted with a board of experts to identify metrics to assess basic psychomotor skills. Based on the output of that survey, 3 novel tasks for surgical assessment were designed. Face and construct validation was performed, with focus on motion-related metrics. Tasks were performed by 42 participants (16 novices, 22 residents, and 4 experts). Movements of the laparoscopic instruments were registered with the TrEndo tracking system and analyzed. Results. Time, path length, and depth showed construct validity for all 3 tasks. Motion smoothness and idle time also showed validity for tasks involving bimanual coordination and tasks requiring a more tactical approach, respectively. Additionally, motion smoothness and average speed showed a high internal consistency, proving them to be the most task-independent of all the metrics analyzed. Conclusion. Motion metrics are complementary and valid for assessing basic psychomotor skills, and their relevance depends on the skill being evaluated. A larger clinical implementation, combined with quality performance information, will give more insight on the relevance of the results shown in this study.

How to objectively classify residents based on their psychomotor laparoscopic skills

Abstract In minimally invasive surgery (MIS), a surgeon needs to acquire a certain level of basic psychomotor MIS skills to perform surgery safely. Evaluation of those skills is a major impediment. Although various assessment methods have been introduced, none of them came as a superior. Three aspects of assessing psychomotor MIS skills are discussed here: (i) advantages and disadvantages of currently available assessment methods, (ii) methods to objectively classify residents according to their level of psychomotor skills, and (iii) factors that influence psychomotor MIS skills. Motion analysis has a potential to be the means to deal with assessment of psychomotor skills. Together with classification methods (e.g. linear discriminant analysis), motion analysis provides an aid in deciding whether a resident is ready to move to the next level of training. Presence of factors that influence psychomotor MIS skills results in a high need for standardisation of valid tasks and setups used for the assessment of MIS skills.

Towards Adaptable Architecture

There is a need for products that can automatically adapt to various environmental and working conditions. Since a standard theoretical framework for designing such adaptable products is not yet established, only few rules, generalized methods, software tools, and guidelines for design for adaptability can be found in literature. The goal of this paper is to address issues associated with designing adaptable product architecture and to propose a first step to develop methods and tools to deal with these issues. The paper first gives various definitions and an overview of product adaptability. Then it discusses adaptable product architectures, external conditions, and customer needs that are crucial aspects in designing adaptable products. The research proposes a scheme of an adaptable product that can constitute part of a formalized design method for adaptability. Finally, it illustrates the design choices that should be made to arrive at an adaptable product architecture.Copyright

Intracorporeal Suturing: Economy of Instrument Movements Using a Box Trainer Model

STUDY OBJECTIVE To determine whether economy of instrument movement can differentiate between skills levels during intracorporeal suturing using a box trainer model. DESIGN Prospective cohort study (Canadian Task Force classification II-2). SETTING Skills laboratory of a university teaching hospital. SUBJECTS Forty-two volunteers participated including 19 medical students without previous laparoscopic experience (novices), 12 residents in obstetrics and gynecology (intermediates), and 11 practitioners of intracorporeal suturing who had performed at least 200 laparoscopic procedures including advanced surgery (experts). INTERVENTIONS Each participant performed 3 consecutive standardized intracorporeal sutures using a box trainer, and instrument movements were recorded using the TrEndo tracking device. MEASUREMENTS AND MAIN RESULTS Time, path length, motion in depth, and motion smoothness of the instrument tips were recorded. Performance in the 3 groups differed significantly (p <.001 for all parameters; Kruskal-Wallis test). Experts outperformed novices in all 4 parameters (p <.01; Bonferroni test). CONCLUSION The construct validity has been suggested for time, path length, motion in depth, and motion smoothness for assessment of the laparoscopic suturing task using a box trainer. An expert level has been set for training and assessment purposes. The addition of economy of movement to time to complete the task has the potential to refine acquisition of skills.