McGill Inanimate System for Training and Evaluation of Laparoscopic Skills (MISTELS)



MISTELS is the technical component of the Fundamentals of Laparoscopic Skills (FLS) certificate program. This is a joint educational program of the Society of American Gastrointestinal and Endoscopic Surgeons (SAGES) and the American College of Surgeons (ACS). As of 2010, the American Board of Surgery (ABS) requires FLS certification for all general surgery residents seeking board certification. Below are the training targets and task for the 5 basic skills.



• Task 1—Peg Transfer: Six plastic objects are transferred on a pegboard. Errors are defined as objects that drop outside the surgeon’s field of view. 


Through the use of two pegboards and six pegs, the operator was required to lift each peg from one pegboard with the left hand, transfer it to the right hand, and place it on the other pegboard. This was then reversed. The aim was to test eye-hand coordination and ambidexterity. This was scored by time to completion with a cutoff time of 300 sec, and a penalty score was given by calculating the percentage of pegs that could not be transferred as a result of being dropped outside the field of view.
















•Task 2—Pattern Cut: A circular pattern is cut along a 1- mm-wide line. Errors are defined as any deviation from the template


This task involved cutting a 4-cm diameter circular pattern out of a 10 × 10 cm piece of gauze suspended between alligator clips. The aim is to use the grasper in one hand placing the material under tension while cutting with the endoscopic scissors in the other hand. The score was determined by time to completion with a cutoff time of 300 sec, and a penalty was determined by calculating the percentage area of deviation from a perfect circle.















• Task 3—Ligating Loop: A loop is placed at a 1-mm-wide line on a foam appendage. Errors are defined as inaccuracy of loop placement and knot insecurity.


This task involved placing two hemostatic clips on a tubular foam structure at premarked positions 3 cm apart, then cutting on a mark halfway between the clips. The purpose was to replicate similar procedures in surgery where clips need to be placed accurately and securely. The score was determined by time to completion (cutoff time 120 sec), and the penalty score was calculated by measuring in millimeters the deviation of the clip or cut from the predrawn lines. A penalty score of 50 points was given for any clip not placed securely or completely across the tube.















•Task 4—Suturing With Extracorporeal Knot-Tying: A 120-cm-long suture is passed through two targets on a Penrose drain, and three knots tied in an extracorporeal fashion are placed using a knot pusher. Errors defined as inaccuracy of suture placement, poor tissue approximation, knot insecurity and pulling the model from its Velcro attachment.


Identical to the previous task, except in this exercise the knot was tied outside the simulator and secured by an extracorporeal technique with a knot pusher. The scoring system used was identical to exercise 4, except the cutoff time was 420 sec.















• Task 5—Suturing With Intracorporeal Knot-Tying: A 12-cm-long suture is used, and three knots are tied in an intracorporeal fashion. The error definition is identical to that for task 4.


This task involved the placement of a simple suture 13 cm in length through premarked points in a longitudinally slit Penrose drain. The suture was then tied using an intracorporeal knot technique. This exercise develops skills at needle transferring, placement of a suture, and knot tying. Scoring involved timing to completion (cutoff time 600 sec), and a penalty score reflecting the accuracy and security of the suture placed. The penalty score measured the distance in millimeters from the premarked points that the suture was placed; the gap in millimeters if the suture failed to approximate the slit; and the security of the knot, given 0 points for a secure knot, 10 points for a slipping knot, and 20 points for a knot that came apart. The sum of these three totaled the penalty score.






















Derossis, A. M., Fried, G. M., Abrahamowicz, M., Sigman, H. H., Barkun, J. S., & Meakins, J. L. (1998).

Development of a model for training and evaluation of laparoscopic skills 1. The American journal of surgery, 

175(6), 482-487.