Systematic review of validity testing in colonoscopy simulation

Simulators and training models for diagnostic and therapeutic gastrointestinal endoscopy: European Society of Gastrointestinal Endoscopy (ESGE) Technical and Technology Review

Gastrointestinal (GI) endoscopy comprises both diagnostic and therapeutic procedures involving the luminal GI tract as well as the biliary tree, liver, and pancreas. GI endoscopy is challenging to learn, requiring both cognitive (nontechnical) and technical skills, and requires extensive practice to attain proficiency. Simulation-based training has been shown to assist trainees and young endoscopists in acquiring new skills and accelerating the learning curve. Moreover, simulation-based training creates an ideal environment for trainees to initially learn and practice skills while making mistakes with no risk to patients.This review, divided in two parts, offers a comprehensive summary of the different classes of simulators available for GI endoscopic training.In Part I, only mechanical simulators are reported and described. In Part II, animal simulators (ex vivo/in vivo) and virtual reality models are detailed, together with prototypes that are currently not commercially available.

Colonoscopy Training on Virtual-Reality Simulators or Physical Model Simulators: A Randomized Controlled Trial

OBJECTIVE

This study employed a randomized controlled trial to assess the efficacy of virtual-reality (VR) simulators and physical model simulators on colonoscopy training to explore the optimal and evidence-based simulation training.

DESIGN

Forty participants were divided into 2 groups and randomized as dyads: the VR simulator group and the physical model simulator group. All the participants performed a baseline test through porcine colonoscopy. After a 6 h simulation training, each participant underwent a post-test on a pig after bowel preparation, and the procedures were video-recorded. Both the baseline test and the post-test were blindly assessed by 2 experienced assistant director physicians based on the GAGES-C scoring system.

SETTING

Simulation center, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai.

PARTICIPANTS

Forty surgical residents without colonoscopy experience.

RESULTS

Both the VR simulator group and the physical model simulator group improved significantly over the baseline test. The VR simulator group performed significantly better than the physical model simulator group, p=0.042. The participants in both groups expressed a high level of simulator satisfaction.

CONCLUSIONS

Novice residents can benefit from both VR simulators and physical model simulators. The VR simulator was shown to be more effective for colonoscopy training. VR simulators were more recommended for novices conducting basic colonoscopy training.

Development and validation of a simulation-based assessment tool in colonoscopy

BACKGROUND

Colonoscopy is difficult to learn. Virtual reality simulation training is helpful, but how and when novices should progress to patient-based training has yet to be established. To date, there is no assessment tool for credentialing novice endoscopists prior to clinical practice. The aim of this study was to develop such an assessment tool based on metrics provided by the simulator. The metrics used for the assessment tool should be able to discriminate between novices, intermediates, and experts and include essential checklist items for patient safety.

METHODS

The validation process was conducted based on the Standards for Educational and Psychological Testing. An expert panel decided upon three essential checklist items for patient safety based on Lawshe's method: perforation, hazardous tension to the bowel wall, and cecal intubation. A power calculation was performed. In this study, the Simbionix GI Mentor II simulator was used. Metrics with discriminatory ability were identified with variance analysis and combined to form an aggregate score. Based on this score and the essential items, pass/fail standards were set and reliability was tested.

RESULTS

Twenty-four participants (eight novices, eight intermediates, and eight expert endoscopists) performed two simulated colonoscopies. Four metrics with discriminatory ability were identified. The aggregate score ranged from 4.2 to 51.2 points. Novices had a mean score of 10.00 (SD 5.13), intermediates 24.63 (SD 7.91), and experts 30.72 (SD 11.98). The difference in score between novices and the other two groups was statistically significant (p<0.01). Although expert endoscopists had a higher score, the difference was not statistically significant (p=0.40). Reliability was good (Cronbach's alpha=0.86). A pass/fail score was defined at 17.1 points with correct completion of three essential checklist items, resulting in three experts and three intermediates failing and one novice passing the assessment.

CONCLUSION

We established a valid and reliable assessment tool with a pass/fail standard on the simulator. We suggest using the assessment after simulation-based training before commencing work-based learning.

The colonoscopic vacuum model-simulating biomechanical restrictions to provide a realistic colonoscopy training environment

INTRODUCTION

Practicing endoscopic procedures is fundamental for the education of clinicians and the benefit of patients. Despite a diverse variety of model types, there is no system simulating anatomical restrictions and variations in a flexible and atraumatic way. Our goal was to develop and validate a new modelling approach for adhesion forces between colon and abdominal wall.

METHODS

An inlay for a standard mechanical trainer was designed and 3D printed. Colon specimens were fixed to the inlay along colon ascendens (CA) and colon descendens (CD) by a vacuum. Our system, which we refer to as Colonoscopy Vacuum Model (CoVaMo), was validated with 11 test persons with varying level of expertise. Each performed one colonoscopy and one polypectomy in the CoVaMo and in the Endoscopic Laparoscopic Interdisciplinary Training Entity (ELITE). Achieved adhesion forces, times required to fulfill different tasks endoscopically and a questionnaire, assessing proximity to reality, were recorded.

RESULTS

Mean adhesion forces of 37 ± 7 N at the CA and 30 ± 15 N at the CD were achieved. Test subjects considered CoVaMo more realistic than ELITE concerning endoscope handling and the overall anatomy. Participants needed statistically significantly more time to maneuver from anus to flexura sinistra in CoVaMo (377 s ± 244 s) than in ELITE (58 s ± 49 s).

CONCLUSION

We developed a training environment enabling anatomically and procedural realistic colonoscopy training requiring participants to handle all endoscope features in parallel. Fixation forces compare to forces needed to tear pig colon off the mesentery. Workflow and inlay can be adapted to any arbitrary ex vivo simulator.

Reperfused human cadaver as a new simulation model for colonoscopy: a pilot study

BACKGROUND

The reperfused human cadaver is a validated simulator for surgery. We aimed to use it as a colonoscopy simulator.

METHODS

Novices, intermediates and skilled participants in gastrointestinal endoscopy were included. They performed one colonoscopy on a reperfused human cadaver and reaching rates, time, and length needed to reach anatomical landmarks were reported for construct validity analysis. We also assessed our model realism (SRS survey), educational content (CVS survey) and task load (NASA-TLX index). Score items were collected and defined as "favorable" when items were rated ≥ 5/7 with an inter-quartile range (IQR) overlapping four, and "very favorable" when rated ≥ 5/7 with an IQR excluding four (neutral). Primary endpoints were the rectosigmoid junction (RSJ) reaching rate and the descending colon (DC) reaching time. Secondary objectives were SRS, CVS and NASA-TLX questionnaire results.

RESULTS

A total of 11 skilled participants, 5 intermediates and 8 novices were included. Skilled participants reached RSJ more often than novice and intermediary groups, respectively, 100%, 80% and 75% without differing significantly. They reached DC more frequently (100% for skilled, 80% for intermediates and 50% for novices, p = 0.018). The median time to reach RSJ (59, 272 and 686 s for skilled, intermediates and novices group, respectively) and DC (90, 534 and 1360 s for skilled, intermediates and novices) was significantly shorter for skilled participants (both p < .01). Nineteen out of the 22 items composing the realism survey obtained "very favorable" and "favorable" scores. Educational content was designated as "very favorable". Mental, physical, and technical demands were gradually higher the lower the initial level of experience.

CONCLUSIONS

Reperfused human cadaver model has the potential to be valid simulation tool for diagnostic colonoscopy training.

An automatic measure of progression during colonoscopy correlates to patient experienced pain

BACKGROUND

Colonoscopy screening and surveillance programs depend on patient's tolerable experience, which is associated with competence of the endoscopist. The Colonoscopy Progression Score (CoPS) is an automated tool based on recording of the Magnetic Scope Imager (MEI) picture in order to track progression. CoPS deliver a numeric score and a graphic map. A high score expresses a rapid and smooth progression. Aims of study were to explore the correlation between CoPS and patient experienced pain and to identity locations associated with pain.

METHODS AND MATERIALS

Patients listed for colonoscopy were included and asked to reply to pain by pressing a rubber ball. The signal was recorded simultaneous to CoPS. Patients evaluated the experience on a Visual Analogue Scale (VAS). CoPS and recorded pain events were used to create a pain sensitive CoPS-map (S-CoPS map).

RESULTS

A total of 58 complete recordings were used for evaluation. We demonstrated a moderate correlation between CoPS and patient experienced pain, Pearson's r = -0.47 (p < .001). A low CoPS was associated with a painful colonoscopy and a high CoPS excluded severe pain. Sensitivity and specificity was 0.79 and 0.60 and AUC was 0.61 Passage of the sigmoid colon, right and left flexures were associated with pain for 51%, 33% and 25% of the patients, respectively.

CONCLUSION

A moderate correlation between CoPS and patient experienced pain suggest that CoPS measure inserting skills but might also be a measure of a gentle performance. The graphic S-CoPS-map can be used to point-out painful passages and aid planning of future colonoscopies.

Robotic-assisted flexible colonoscopy: preliminary safety and efficiency in humans

BACKGROUND AND AIMS

The flexible endoscope is used as a platform for minimally invasive interventions. However, control of the conventional endoscope and multiple instruments is difficult. Robotic assistance could provide a solution and better control for a single operator. A novel platform should also enable interventions in areas that are currently difficult to reach. This study evaluates the safety and efficacy of a robotic platform that guides a conventional endoscope through the large bowel.

METHODS

Adult patients scheduled for routine diagnostic colonoscopy were included in this feasibility study. The endoscope was introduced using a robotic add-on to provide tip bending and air/water actuation. The endoscopist directly controlled the endoscope shaft. Upon cecal intubation, the add-on was detached and the procedure continued using conventional control. Primary evaluation parameters were the number of serious adverse events and the percentage of successful cecal intubations.

RESULTS

The procedure was performed on 22 consecutive patients who all gave informed consent. There were no serious adverse events. Cecal intubation was successful in 15 patients (68%) using the robotic add-on. Six cases were completed after conversion to conventional control: 3 cases were converted to pass sharp angulation in the flexures and 3 cases were converted after technical difficulties. One case was not successful with either technique because of severe diverticulosis.

CONCLUSIONS

The robotic add-on steering module allows safe endoscope intubation to reach intervention sites throughout the large bowel. The next step is to clinically evaluate complementary instrument and shaft-guiding modules in therapeutic procedures.

A Review of Endoscopic Simulation: Current Evidence on Simulators and Curricula

Upper and lower endoscopy is an important tool that is being utilized more frequently by general surgeons. Training in therapeutic endoscopic techniques has become a mandatory requirement for general surgery residency programs in the United States. The Fundamentals of Endoscopic Surgery has been developed to train and assess competency in these advanced techniques. Simulation has been shown to increase the skill and learning curve of trainees in other surgical disciplines. Several types of endoscopy simulators are commercially available; mechanical trainers, animal based, and virtual reality or computer-based simulators all have their benefits and limitations. However they have all been shown to improve trainee's endoscopic skills. Endoscopic simulators will play a critical role as part of a comprehensive curriculum designed to train the next generation of surgeons. We reviewed recent literature related to the various types of endoscopic simulators and their use in an educational curriculum, and discuss the relevant findings.

Kinematic analysis of wrist motion during simulated colonoscopy in first-year gastroenterology fellows

BACKGROUND AND STUDY AIMS

Gastroenterology trainees acquire skill and proficiency in performing colonoscopies at different rates. The cause for heterogeneous competency among the trainees is unclear. Kinematic analysis of the wrist joint while performing colonoscopy can objectively assess the variation in wrist motion. Our objective was to test the hypothesis that the time spent by the trainees in extreme ranges of wrist motion will decrease as the trainees advance through the fellowship year.

SUBJECTS AND METHODS

Five first-year gastroenterology fellows were prospectively studied at four intervals while performing simulated colonoscopies. The setting was an endoscopy simulation laboratory at a tertiary care center. Kinematic assessment of wrist motion was done using a magnetic position/orientation tracker held in place by a custom-made arm sleeve and hand glove. The main outcome measure was time spent performing each of four ranges of wrist motion (mid, center, extreme, and out) for each wrist degree of freedom (pronation/supination, flexion/extension, and adduction/abduction).

RESULTS

There were no statistically significant differences in the time spent for wrist movements across the three degrees of freedom throughout the study period. However, fellows spent significantly less time in extreme range (1.47 ± 0.34 min vs. 2.44 ± 0.34 min, P = 0.004) and center range (1.02 ± 0.34 min vs 1.9 ± 0.34 min, P = 0.01) at the end of the study compared to the baseline evaluation. The study was limited by the small number of subjects and performance of colonoscopies on a simulator rather than live patients.

CONCLUSIONS

Gastroenterology trainees alter the time spent at the extreme range of wrist motion as they advance through training. Endoscopy training during the first 10 months of fellowship may have beneficial effects on learning ergonomically correct motion patterns.

Simulation-based training for colonoscopy: establishing criteria for competency

The aim of this study was to create simulation-based tests with credible pass/fail standards for 2 different fidelities of colonoscopy models. Only competent practitioners should perform colonoscopy. Reliable and valid simulation-based tests could be used to establish basic competency in colonoscopy before practicing on patients. Twenty-five physicians (10 consultants with endoscopic experience and 15 fellows with very little endoscopic experience) were tested on 2 different simulator models: a virtual-reality simulator and a physical model. Tests were repeated twice on each simulator model. Metrics with discriminatory ability were identified for both modalities and reliability was determined. The contrasting-groups method was used to create pass/fail standards and the consequences of these were explored. The consultants significantly performed faster and scored higher than the fellows on both the models (P < 0.001). Reliability analysis showed Cronbach α = 0.80 and 0.87 for the virtual-reality and the physical model, respectively. The established pass/fail standards failed one of the consultants (virtual-reality simulator) and allowed one fellow to pass (physical model). The 2 tested simulations-based modalities provided reliable and valid assessments of competence in colonoscopy and credible pass/fail standards were established for both the tests. We propose to use these standards in simulation-based training programs before proceeding to supervised training on patients.

Characterization of right wrist posture during simulated colonoscopy: an application of kinematic analysis to the study of endoscopic maneuvers

BACKGROUND

Endoscopic maneuvers are associated with a high incidence of musculoskeletal injuries.

OBJECTIVE

To quantify wrist motion patterns during simulated endoscopic procedures to identify potential causes of endoscopy-related overuse injury.

DESIGN

Twelve endoscopists with different levels of experience were tested on 2 simulated endoscopic procedures that differed in their level of difficulty.

SETTING

Right wrist movement patterns were recorded during simulated colonoscopies by using a magnetic motion-tracking device. Analysis focused on 3 wrist degrees of freedom: abduction/adduction, flexion/extension, and pronation/supination.

INTERVENTIONS

Subjects were tested on 2 GI lower endoscopies (colonoscopies) on a simulator.

MAIN OUTCOME MEASUREMENTS

Time spent within ranges of the entire wrist range of motion for 3 wrist degrees of freedom.

RESULTS

Endoscopists spent up to 30% of the duration of the procedures at the extremes of the wrist joint range of motion. Endoscopic experience did not affect the time spent at the extremes of the wrist joint of motion. The time spent within each range of motion differed depending on the wrist degrees of freedom and difficulty of procedure.

LIMITATIONS

This study examined only 1 upper limb joint in a limited number of subjects and did not measure interaction forces with endoscopic tools.

CONCLUSIONS

We identified wrist movement patterns that can potentially contribute to the occurrence of musculoskeletal injury in endoscopists. This study lays the foundation for future work on establishing links between upper limb movement patterns and the occurrence of overuse injury caused by repetitive performance of endoscopic procedures.