Effects of laparoscopic instrument and finger on force perception: a first step towards laparoscopic force-skills training

Effects of Real Time Feedback on Novice's Laparoscopic Learning Curve

OBJECTIVE

Analyze the learning curve of medical students when they are trained with a laparoscopic box trainer and are presented with different modes of real-time feedback on their performance in the laparoscopic suturing procedure.

DESIGN

A prospective randomized controlled trial (RTC) was performed. Three groups were proposed: control, visual, and haptic. The block randomization technique was used to assign the participants to one of the three groups. Each group trained the intracorporeal square flat knot task in a standardized FLS box simulator. A total of 11 sessions were programmed for this study: a pre-training session, eight training sessions, a post-training session, and a follow-up session. Measurement of the generated reaction force during the task were taken weekly for the first 10 sessions (pre-training, training, and post-training); then, the follow-up measurement was taken a month after.

SETTING

This study was carried out in a single center at the Unidad de Simulación de Posgrado (USIP) of the postgraduate medicine program of the Universidad Nacional Autónoma de México (UNAM) between May and August 2023.

PARTICIPANTS

The eligible participants were medical students without experience in minimally invasive surgery. All social service intern medics doing their social service in the USIP were invited to participate. A total of 20 participants entered the study from which 18 of them finished all the programmed sessions.

RESULTS

A total of ten metrics were extracted from the reaction force signal measured at each session. All metrics are directly proportional to the reaction force and low magnitudes imply high tissue-handling proficiency. All groups improved their tissue handling skills, being the visual group the one who achieved better performance, followed by the haptic group and lastly the control group.

CONCLUSION

The use of real time feedback, especially visual feedback can help novices to shorten the learning process of tissue handling and achieve a better proficiency in advanced tasks in shorter training periods.

Haptic based fundamentals of laparoscopic surgery simulation for training with objective assessments

Force is crucial for learning psychomotor skills in laparoscopic tissue manipulation. Fundamental laparoscopic surgery (FLS), on the other hand, only measures time and position accuracy. FLS is a commonly used training program for basic laparoscopic training through part tasks. The FLS is employed in most of the laparoscopic training systems, including box trainers and virtual reality (VR) simulators. However, many laparoscopic VR simulators lack force feedback and measure tissue damage solely through visual feedback based on virtual collisions. Few VR simulators that provide force feedback have subjective force metrics. To provide an objective force assessment for haptic skills training in the VR simulators, we extend the FLS part tasks to haptic-based FLS (HFLS), focusing on controlled force exertion. We interface the simulated HFLS part tasks with a customized bi-manual haptic simulator that offers five degrees of freedom (DOF) for force feedback. The proposed tasks are evaluated through face and content validity among laparoscopic surgeons of varying experience levels. The results show that trainees perform better in HFLS tasks. The average Likert score observed for face and content validity is greater than 4.6 ± 0.3 and 4 ± 0.5 for all the part tasks, which indicates the acceptance of the simulator among subjects for its appearance and functionality. Face and content validations show the need to improve haptic realism, which is also observed in existing simulators. To enhance the accuracy of force rendering, we incorporated a laparoscopic tool force model into the simulation. We study the effectiveness of the model through a psychophysical study that measures just noticeable difference (JND) for the laparoscopic gripping task. The study reveals an insignificant decrease in gripping-force JND. A simple linear model could be sufficient for gripper force feedback, and a non-linear LapTool force model does not affect the force perception for the force range of 0.5-2.5 N. Further study is required to understand the usability of the force model in laparoscopic training at a higher force range. Additionally, the construct validity of HFLS will confirm the applicability of the developed simulator to train surgeons with different levels of experience.

A systematic review on classification and assessment of surgical skill levels for simulation-based training programs

BACKGROUND

Nowadays, advances in medical informatics have made minimally invasive surgery (MIS) procedures the preferred choice. However, there are several problems with the education programs in terms of surgical skill acquisition. For instance, defining and objectively measuring surgical skill levels is a challenging process. Accordingly, the aim of this study is to conduct a literature review for an investigation of the current approaches for classifying the surgical skill levels and for identifying the skill training tools and measurement methods.

MATERIALS AND METHODS

In this research, a search is conducted and a corpus is created. Exclusion and inclusion criteria are applied by limiting the number of articles based on surgical education, training approximations, hand movements, and endoscopic or laparoscopic operations. To satisfy these criteria, 57 articles are included in the corpus of this study.

RESULTS

Currently used surgical skill assessment approaches have been summarized. Results show that various classification approaches for the surgical skill level definitions are being used. Besides, many studies are conducted by omitting particularly important skill levels in between. Additionally, some inconsistencies are also identified across the skill level classification studies.

CONCLUSION

In order to improve the benefits of simulation-based training programs, a standardized interdisciplinary approach should be developed. For this reason, specific to each surgical procedure, the required skills should be identified. Additionally, appropriate measures for assessing these skills, which can be defined in simulation-based MIS training environments, should be refined. Finally, the skill levels gained during the developmental stages of these skills, with their threshold values referencing the identified measures, should be redefined in a standardized manner.

Haptic exploration improves performance of a laparoscopic training task

BACKGROUND

Laparoscopy has reduced tactile and visual feedback compared to open surgery. There is increasing evidence that visual and haptic information converge to form a more robust mental representation of an object. We investigated whether tactile exploration of an object prior to executing a laparoscopic action on it improves performance.

METHODS

A prospective cohort study with 20 medical students randomized in two different groups was conducted. A silicone ileocecal model, on which a laparoscopic action had to be performed, was used inside an outside a ForceSense box trainer. During the pre-test, students either did a combined manual and visual exploration or only visual exploration of the caecum model. To track performance during the trials of the study we used force, motion and time parameters as representatives of technical skills development. The final trial data were used for statistical comparison between groups.

RESULTS

All included time and motion parameters did not show any clear differences between groups. However, the force parameters Mean force non-zero (p = 004), Maximal force (p = 0.01) Maximal impulse (p = 0.02), Force volume (p = 0.02) and SD force (p = 0.01) showed significant lower values in favour of the tactile exploration group for the final trials.

CONCLUSIONS

By adding haptic sensation to the existing visual information during training of laparoscopic tasks on life-like models, tissue manipulation skills improve during training.

Construct validity of the SurgForce system for objective assessment of laparoscopic suturing skills

BACKGROUND

Laparoscopic surgery requires a new set of skill to be learned by the surgeons, of which the most relevant is tissue manipulation. Excessive forces applied to the tissue can cause rupture during manipulation or ischemia when confronting both sides of the tissue. The aim of this study is to establish the construct validity of the SurgForce system for objective assessment of advanced laparoscopic skills, based on the force signal generated during suture tasks, and the development of force parameters for evaluating tissue handling interaction.

METHODS

The SurgForce system, a tissue handling training device that measures dynamic force, was used to capture the force generated by surgeons with different levels of laparoscopic experience. For construct validity, 37 participants were enrolled in this study: 19 medical students, 12 residents of surgical specialties and 6 expert surgeons. All participants performed an intracorporeal knotting suture task over a synthetic tissue pad with a laparoscopic box-trainer. The force performance of the participants was analyzed using 11 force-based parameters with the application of the SurgForce system. Statistical analysis was performed between novice, intermediate, and expert groups using a Kruskal-Wallis test, and between the pairs of groups using a Mann-Whitney U-test.

RESULTS

Overall, 9 of the 11 force-related parameters showed significant differences between the three study groups. Results between the pairs of groups presented significant differences in 5 force parameters proposed. Construct validity results demonstrated that the SurgForce system was able to differentiate force performance between surgeons with different levels of laparoscopic experience.

CONCLUSION

The SurgForce system was successfully validated. This force system showed its potential to measure the force exerted on tissue for objective assessment of tissue handling skills in suturing tasks. Furthermore, its compact design allows the use of this device in conventional laparoscopic box-trainers.

Accuracy of Dynamic Force Compensation Varies With Direction and Speed

This study investigates physical responses to force perturbations while tracking a moving target. The results show accuracy depends on the direction of a force perturbation and speed of the task, but generally not on hand. There are also differences in responses when the force is first applied and when it is removed.

Haptic Feedback, Force Feedback, and Force-Sensing in Simulation Training for Laparoscopy: A Systematic Overview

OBJECTIVES

To provide a systematic overview of the literature assessing the value of haptic and force feedback in current simulators teaching laparoscopic surgical skills.

DATA SOURCES

The databases of Pubmed, Cochrane, Embase, Web of Science, and Google Scholar were searched to retrieve relevant studies published until January 31st, 2017. The search included laparoscopic surgery, simulation, and haptic or force feedback and all relevant synonyms.

METHODS

Duplicates were removed, and titles and abstracts screened. The remaining articles were subsequently screened full text and included in this review if they followed the inclusion criteria. A total of 2 types of feedback have been analyzed and will be discussed separately: haptic- and force feedback.

RESULTS

A total of 4023 articles were found, of which 87 could be used in this review. A descriptive analysis of the data is provided. Results of the added value of haptic interface devices in virtual reality are variable. Haptic feedback is most important for more complex tasks. The interface devices do not require the highest level of fidelity. Haptic feedback leads to a shorter learning curve with a steadier upward trend. Concerning force feedback, force parameters are measured through force sensing systems in the instrument and/or the environment. These parameters, especially in combination with motion parameters, provide box trainers with an objective evaluation of laparoscopic skills. Feedback of force-use both real time and postpractice has been shown to improve training.

CONCLUSIONS

Haptic feedback is added to virtual reality simulators to increase the fidelity and thereby improve training effect. Variable results have been found from adding haptic feedback. It is most important for more complex tasks, but results in only minor improvements for novice surgeons. Force parameters and force feedback in box trainers have been shown to improve training results.

Face and Construct Validity of a Novel Virtual Reality-Based Bimanual Laparoscopic Force-Skills Trainer With Haptics Feedback

BACKGROUND

The purpose of this study was to examine the face and construct validity of a custom-developed bimanual laparoscopic force-skills trainer with haptics feedback. The study also examined the effect of handedness on fundamental and complex tasks.

METHODS

Residents (n = 25) and surgeons (n = 25) performed virtual reality-based bimanual fundamental and complex tasks. Tool-tissue reaction forces were summed, recorded, and analysed. Seven different force-based measures and a 1-time measure were used as metrics. Subsequently, participants filled out face validity and demographic questionnaires.

RESULTS

Residents and surgeons were positive on the design, workspace, and usefulness of the simulator. Construct validity results showed significant differences between residents and experts during the execution of fundamental and complex tasks. In both tasks, residents applied large forces with higher coefficient of variation and force jerks (P < .001). Experts, with their dominant hand, applied lower forces in complex tasks and higher forces in fundamental tasks (P < .001). The coefficients of force variation (CoV) of residents and experts were higher in complex tasks (P < .001). Strong correlations were observed between CoV and task time for fundamental (r = 0.70) and complex tasks (r = 0.85). Range of smoothness of force was higher for the non-dominant hand in both fundamental and complex tasks.

CONCLUSIONS

The simulator was able to differentiate the force-skills of residents and surgeons, and objectively evaluate the effects of handedness on laparoscopic force-skills. Competency-based laparoscopic skills assessment curriculum should be updated to meet the requirements of bimanual force-based training.

Haptic Feedback in Needle Insertion Modeling and Simulation

Needle insertion is the most basic skill in medical care, and training has to be imparted not only for physicians but also for nurses and paramedics. In most needle insertion procedures, haptic feedback from the needle is the main stimulus in which novices need training. For better patient safety, the classical methods of training the haptic skills have to be replaced with simulators based on new robotic and graphics technologies. This paper reviews the current advances in needle insertion modeling, classified into three sections: needle insertion models, tissue deformation models, and needle-tissue interaction models. Although understated in the literature, the classical and dynamic friction models, which are critical for needle insertion modeling, are also discussed. The experimental setup or the needle simulators that have been developed to validate the models are described. The need of psychophysics for needle simulators and psychophysical parameter analysis of human perception in needle insertion are discussed, which are completely ignored in the literature.

Objective Assessment of Laparoscopic Force and Psychomotor Skills in a Novel Virtual Reality-Based Haptic Simulator

BACKGROUND

Most of the commercially available virtual reality-based laparoscopic simulators do not effectively evaluate combined psychomotor and force-based laparoscopic skills. Consequently, the lack of training on these critical skills leads to intraoperative errors.

OBJECTIVES

To assess the effectiveness of the novel virtual reality-based simulator, this study analyzed the combined psychomotor (i.e., motion or movement) and force skills of residents and expert surgeons. The study also examined the effectiveness of real-time visual force feedback and tool motion during training.

DESIGN

Bimanual fundamental (i.e., probing, pulling, sweeping, grasping, and twisting) and complex tasks (i.e., tissue dissection) were evaluated. In both tasks, visual feedback on applied force and tool motion were provided. The skills of the participants while performing the early tasks were assessed with and without visual feedback. Participants performed 5 repetitions of fundamental and complex tasks. Reaction force and instrument acceleration were used as metrics.

SETTING

Surgical Gastroenterology, Government Stanley Medical College and Hospital; Institute of Surgical Gastroenterology, Madras Medical College and Rajiv Gandhi Government General Hospital.

PARTICIPANTS

Residents (N = 25; postgraduates and surgeons with <2 years of laparoscopic surgery) and expert surgeons (N = 25; surgeons with >4 and ≤10 years of laparoscopic surgery).

RESULTS

Residents applied large forces compared with expert surgeons and performed abrupt tool movements (p < 0.001). However, visual + haptic feedback improved the performance of residents (p < 0.001). In complex tasks, visual + haptic feedback did not influence the applied force of expert surgeons, but influenced their tool motion (p < 0.001). Furthermore, in complex tissue sweeping task, expert surgeons applied more force, but were within the tissue damage limits. In both groups, exertion of large forces and abrupt tool motion were observed during grasping, probing or pulling, and tissue sweeping maneuvers (p < 0.001).

CONCLUSIONS

Modern day curriculum-based training should evaluate the skills of residents with robust force and psychomotor-based exercises for proficient laparoscopy. Visual feedback on force and motion during training has the potential to enhance the learning curve of residents.