Gerald M. Fried

Proving the value of simulation in laparoscopic surgery

Objective:To assess the McGill Inanimate System for Training and Evaluation of Laparoscopic Skills (MISTELS) physical laparoscopic simulator for construct and predictive validity and for its educational utility. Summary Background Data:MISTELS is the physical simulator incorporated by the Society of American Gastrointestinal and Endoscopic Surgeons (SAGES) in their Fundamentals of Laparoscopic Surgery (FLS) program. MISTELS’ metrics have been shown to have high interrater and test-retest reliability and to correlate with skill in animal surgery. Methods:Over 200 surgeons and trainees from 5 countries were assessed using MISTELS in a series of experiments to assess the validity of the system and to evaluate whether practicing MISTELS basic skills (transferring) would result in skill acquisition transferable to complex laparoscopic tasks (suturing). Results:Face validity was confirmed through questioning 44 experienced laparoscopic surgeons using global rating scales. MISTELS scores increased progressively with increasing laparoscopic experience (n = 215, P < 0.0001), and residents followed over time improved their scores (n = 24, P < 0.0001), evidence of construct validity. Results in the host institution did not differ from 5 beta sites (n = 215, external validity). MISTELS scores correlated with a highly reliable validated intraoperative rating of technical skill during laparoscopic cholecystectomy (n = 19, r = 0.81, P < 0.0004; concurrent validity). Novice laparoscopists were randomized to practice/no practice of the transfer drill for 4 weeks. Improvement in intracorporeal suturing skill was significantly related to practice but not to baseline ability, career goals, or gender (P < 0.001). Conclusion:MISTELS is a practical and inexpensive inanimate system developed to teach and measure technical skills in laparoscopy. This system is reliable, valid, and a useful educational tool.

Development of a Model for Training and Evaluation of Laparoscopic Skills

BACKGROUND Interest in the training and evaluation of laparoscopic skills is extending beyond the realm of the operating room to the use of laparoscopic simulators. The purpose of this study was to develop a series of structured tasks to objectively measure laparoscopic skills. This model was then used to test for the effects of level of training and practice on performance. METHODS Forty-two subjects (6 each of surgical residents PGY1 to PGY5, 6 surgeons who practice laparoscopy and 6 who do not) were evaluated. Each subject viewed a 20-minute introductory video, then was tested performing 7 laparoscopic tasks (peg transfers, pattern cutting, clip and divide, endolooping, mesh placement and fixation, suturing with intracorporeal or extracorporeal knots). Performance was measured using a scoring system rewarding precision and speed. Each candidate repeated all 7 tasks and was rescored. Data were analyzed by linear regression to assess the relationship of performance with level of residency training for each task, and by ANOVA with repeated measures to test for effects of level of training, of repetition, and of the interaction between level of training and repetition on overall performance. Students t test was used to evaluate differences between laparoscopic and nonlaparoscopic surgeons and between each of these groups and the PGY 5 level of surgical residents. RESULTS Significant predictors of overall performance were (a) level of training (P = 0.002), (b) repetition (P < 0.0001), and (c) interaction between level of training and practice (P = 0.001). There was also a significant interaction between level of training and the specific task on performance scores (P = 0.006). When each task was evaluated individually for the 30 residents, 4 of the 7 tasks (tasks 1, 2, 6, 7) showed significant correlation between PGY level and score. A significant difference in performance scores between laparoscopic and nonlaparoscopic surgeons was seen for tasks 1, 2, and 6. CONCLUSIONS A model was developed to evaluate laparoscopic skills. Construct validity was demonstrated by measuring significant improvement in performance with increasing residency training, and with practice. Further validation will require correlation of performance in the model with skill in vivo.

Development and validation of a comprehensive program of education and assessment of the basic fundamentals of laparoscopic surgery

IN THE LATE 1990S THE Society of American Gastrointestinal Endoscopic Surgery (SAGES) formed a committee (Fundamentals of Laparoscopic Surgery or FLS) and charged it to develop educational materials covering the basic fundamentals of laparoscopic surgery. Four major principles guided the committee’s developmental process. First, comprehensive coverage of the domain of basic laparoscopy was seen as involving two components: one cognitive (declarative knowledge); and the other psychomotor (procedural skill). Second, the focus of the program was to be on the educational material considered unique to laparoscopy and not on material normally encountered during open surgical training. Third, in accordance with the idea of basic fundamentals, any content specific to a particular anatomic location or to a specific laparoscopic procedure was to be avoided. And fourth, the program was to contain mechanisms for assessment as well as for didactic instruction. The overall goal of the FLS program was to ‘‘teach a standard set of cognitive and psychomotor skills to practitioners of laparoscopic surgery’’ in the belief that knowledge and application of these fundamentals would help ‘‘ensure a minimal standard of care for all patients undergoing laparoscopic surgery.’’ The didactic learning modules are

Randomised controlled trial of laparoscopic versus mini cholecystectomy

Laparoscopic cholecystectomy (LC) has gained wide acceptance for treatment of cholelithiasis in preference to open cholecystectomy, though it has not been formally compared with mini cholecystectomy (MC). We have compared these two techniques in a randomised trial. 70 patients with ultrasound-proven cholelithiasis were randomly allocated LC (38) or MC (32); 37 and 25, respectively, underwent the assigned procedure. The mean hospital stay (including 1 preoperative day) was significantly shorter in the LC than the MC group (median 3 [interquartile range 2-3] vs 4 [3-5], p = 0.001) as was duration of convalescence (mean 11.9 [SD 9.1] vs 20.2 [16.5] days, p = 0.04). The rate of return to normal activities was 1.77 times greater in the LC group than in the MC group (95% confidence interval 1.01-3.11, p = 0.03). In regression analysis, the type of cholecystectomy done was the only variable significantly associated with the duration of convalescence. Although there was significant postoperative improvement in all of three quality of life scores in both groups, LC patients improved more quickly than did MC patients. This randomised trial shows the superior effectiveness of LC over MC in treating cholelithiasis.

Fundamentals of Laparoscopic Surgery simulator training to proficiency improves laparoscopic performance in the operating room—a randomized controlled trial

BACKGROUND The purpose of this study was to assess whether training to proficiency with the Fundamentals of Laparoscopic Surgery (FLS) simulator would result in improved performance in the operating room (OR). METHODS Nineteen junior residents underwent baseline FLS testing and were assessed in the OR using a validated global rating scale (GOALS) during elective laparoscopic cholecystectomy. Those with GOALS scores <or=15 were randomly assigned to training (n = 9) or control (n = 8) groups. An FLS proficiency-based curriculum was used in the training group. Scoring on FLS and in the OR was repeated after the study period. Evaluators were blinded to randomization status. RESULTS Sixteen residents completed the study. There were no differences in baseline simulator (49.1 +/- 17 vs 39.5 +/- 16, P = .27) or OR scores (11.3 +/- 2.0 vs 12.0 +/- 1.8; P = .47). After training, simulator scores were higher in the trained group (95.1 +/- 4 vs 60.5 +/- 23, P = .004). OR performance improved in the control group by 1.8 to 13.8 +/- 2.2 (P = .04), whereas the trained group improved by 6.1 to 17.4 +/- 1.9 (P = .0005 vs control; P < .0001 vs baseline). CONCLUSIONS This study clearly demonstrates the educational value of FLS simulator training in surgical residency curricula.

Evaluating laparoscopic skills

Background: The McGill Inanimate System for Training and Evaluation of Laparoscopic Skills (MISTELS) was developed to assess laparoscopic skills and to score them objectively. This system has been described previously. The purpose of the current study was to determine a pass/fail threshold. Methods: In this study. 165 individuals were tested and grouped according to their clinical competency in laparoscopic surgery. The noncompetent group consisted of medical students and surgical residents in their first 2 years of training (n = 83). The competent group consisted of chief general surgical residents in their last year of training, laparoscopy fellows. and practicing laparoscopic surgeons (n = 82). The Mann-Whitney U test was used to evaluate differences in task performance between the two groups. Results: There was a significant difference in total scores and individual MISTELS task scores between the noncompetent and competent laparoscopic surgeons (189 vs 372.5; p < 0.0001). By setting specific pass/fail total score thresholds (cutoff scores), competent surgeons can be discriminated from noncompetent surgeons. Conclusion: An objective pass/fail evaluation can be given to individuals tested with the MISTELS system.

Useful predictors of bile duct stones in patients undergoing laparoscopic cholecystectomy

ObjectiveThe authors determined the most useful predictors of common bile duct (CBD) stones as diagnosed by endoscopic retrograde cholangiopancreatography (ERCP) in patients who underwent laparoscopic cholecystectomy (LC). MethodsProspective and retrospective collection of historical, biochemical and ultrasonographic data was used. Receiver operating characteristics curve analysis was used to determine optimal biochemical cut-off values. Multivariate analysis using logistic regression with generation of the best model identifying independent predictors of CBD stones also was employed. Prospective validation of the model was performed on an independent group of patients. ResultsEndoscopic retrograde cholangiopancreatographies were performed before LC in 106 patients, and after LC in 33. Only four of ten clinical variables evaluated independently predicted the presence of CBD stones. The optimal model predicted a 94% probability of CBD stones in a patient older than 55 years of age who presented with an elevated biliubin (over 30 μmol/L) and positive ultrasound findings (a dilated CBD, and a CBD stone seen on ultrasound). This model was validated prospectively in a subsequent series of 49 patients in which the probability of CBD stone was only 8% when all four predictors were absent. ConclusionsThe identified independent clinical predictors of a CBD stone helps select a population of symptomatic gallstone bearers who benefit most from cholangiographic assessment.

Factors determining conversion to laparotomy in patients undergoing laparoscopic cholecystectomy

Laparoscopic cholecystectomy (LC) has been performed increasingly in an outpatient setting. Conversion from LC to open cholecystectomy (OC) is sometimes required. To predict conversion to OC, a single institutional study of 1,676 consecutive patients in whom LC was attempted was performed. Factors evaluated were age, sex, history of acute cholecystitis, pancreatitis, or jaundice, previous abdominal surgery, abnormalities of liver function tests, thickened gallbladder wall identified by preoperative ultrasound, obesity or morbid obesity, and cumulative institutional experience in LC. Conversion to OC was required in 90 of 1,676 (5.4%) patients. Significant preoperative predictors of conversion were acute cholecystitis, increasing age, male sex, obesity, and thickened gallbladder wall found by ultrasound. Nonobese women younger than age 65 years with symptoms of biliary colic and normal gallbladder wall thickness found by preoperative ultrasound required conversion only 1.9% of the time. These predictors may be useful in planning a program of ambulatory or short stay surgical units for patients undergoing LC and for comparing data between series.

Peroral Endoscopic Myotomy for the Treatment of Achalasia: An International Prospective Multicenter Study

Pilot studies have indicated that peroral endoscopic myotomy (POEM) might be a safe and effective treatment for achalasia. We performed a prospective, international, multicenter study to determine the outcomes of 70 patients who underwent POEM at 5 centers in Europe and North America. Three months after POEM, 97% of patients were in symptom remission (95% confidence interval, 89%-99%); symptom scores were reduced from 7 to 1 (P < .001) and lower esophageal sphincter pressures were reduced from 28 to 9 mm Hg (P < .001). The percentage of patients in symptom remission at 6 and 12 months was 89% and 82%, respectively. POEM was found to be an effective treatment for achalasia after a mean follow-up period of 10 months.

Experimental evidence for a vagally mediated and cholecystokinin-independent enteropancreatic reflex

: The natural history of gallstone disease in 691 patients, followed for a mean +/- SD duration of 78 +/- 61.6 months (median 62.9 months), is presented. These patients are all subscribers of a large health maintenance organization and are believed to represent a cross-section of middle income Americans. Symptoms attributed to biliary tract disease were present in 556 (80.5%), and the other 135 (19.5%) patients were asymptomatic. In the symptomatic group, the mean +/- SD duration of observation was 82.9 +/- 63.2 months (median 68.5 months); 242 (44%) eventually underwent biliary tract operations most often because of persistent symptoms. Only 10% of asymptomatic patients followed for 58 +/- 50.2 months (median 46.3 months) developed symptoms of biliary calculi, and seven per cent required operations. There were 50 deaths in this series of 691 patients, 25 in the symptomatic group, and 25 in the asymptomatic. Only two of these deaths were biliary tract related, and both were in the symptomatic group. This study suggests that patients with silent stones do not need to be operated on prior to the development of symptoms. In addition, many patients with symptoms of biliary calculi can tolerate their symptoms for long periods of time and prefer this course of action to cholecystectomy.Truncal vagotomy results in diminished pancreatic protein secretion in response to intraduodenal fat. This diminished secretion may be due, at least in part, to interruption of the vagal reflexes between the intestine and the pancreas that work independently of cholecystokinin (CCK). In five dogs with chronic pancreatic fistulas, plasma CCK concentrations and pancreatic protein secretion in response to an intestinal stimulant (intraduodenal oleate) and to two exogenous peptides (bombesin and CCK-33) were compared before and after bilateral truncal vagotomy. Vagotomy decreased integrated protein secretion by about 50% in response to intraduodenal oleate. In contrast, protein output in response to parenteral stimuli increased after vagotomy. Integrated output of CCK in response to intraduodenal oleate or to exogenous bombesin or CCK was not significantly affected by vagotomy, but release of pancreatic polypeptide was decreased significantly in response to all stimuli after truncal vagotomy. These data provide evidence that truncal vagotomy decreases pancreatic protein secretion in response to intestinal stimulants by interrupting enteropancreatic reflexes mediated by the vagus, while maintaining normal (or supranormal) sensitivity of the pancreas to endogenous and exogenous CCK.