Types of Simulator

There is little doubt that carrying out procedures and learning on live patients is the best method of learning. However, there are a variety of ways that “day-to- day” situations can be mimicked allowing a novice to commence learning a skill, or someone more advanced to develop their skills. Simulations have the added advantage of avoiding many ethical and safety issues that present when dealing with live patients72. The reproducibility of a task that can be created with these simulations means that junior surgeons can commence learning tasks and build confidence in a safe environment.

Sarker et al suggested that simulators can be broken down into several models; inorganic (subdivided into synthetic and electronic), and organic (further divided into cadaveric and animal simulators)72_.

The synthetic models can be further divided into non-life and lifelike. Non-lifelike models are simply devices that allow a particular skill to be practiced. A typical example of this is the wooden blocks used in teaching the hand tying of knots. The model itself represents no similarity to real life, however, it allows a vital skill to be taught and rehearsed. The device used on basic surgical skills courses also involves using a “shoe-lace” half black and half white. This is a useful device that allows the teacher and the student to demonstrate the knot has been tied correctly by the distinctive pattern that is produced.

Lifelike synthetic models may differ in how realistic they are. On a simple scale latex and rubber can be used to recreate surgical scenarios. Simpler models are naturally less expensive and good for teaching and learning surgical techniques whilst more expensive models can be used to recreate more complicated activities, perhaps with several steps allowing a complete procedure to be learnt. These skills can then be transferred to real life situations, with the student hopefully far nearer the top of the learning curve.

The use of electronic or virtual reality simulations is ever increasing. Virtual reality has been defined as “technology that allows people to interact efficiently with three dimensional computerised databases in real time using their natural senses and skills”.73 _{Simulators that}

recreating laparoscopic and endoscopic scenarios. The obvious advantage is the safe environment for learning that is recreated. Part of a procedure can be taught and practised repeatedly, or several steps of the procedure can be taught. This allows progress to be made with all the required steps and potentially a whole procedure learnt with a good degree of technical confidence before going onto operate on a live patient. The other advantages include real-time performance and reproducibility. Further the opportunity to develop a level of competence before trying these techniques on patients has ethical advantages. The ethos of see one, do one, teach one, has long been superseded and patients increasingly expect a consultant led service and thus their procedures should be carried out by the consultant. While appropriate supervision is naturally necessary until the required level of competence is reached, simulators undoubtedly will mean that levels of independence can be reached more rapidly.

Often motor skill performance is judged by time taken to perform a task and the accuracy with which the task is performed. While these two criteria are obviously important in determining whether an individual has successfully learnt how to carry out a task it fails to take into account the amount of effort required to get to the end point. Anecdotally it is often noticeable when watching different surgeons carry out the same procedure that some appear effortless whilst other can make the task appear more difficult. Whilst in some cases this may be down to experience, it could also be related to the way the individual was taught, and an element of natural ability. There is a difference between being competent at a task and effortless in the same task. In this way computerised simulators may be of use in analysing movements and effort required to accomplish a task. With the benefit of these tools individuals may not only just be able to become competent in the skill, but be able to analyse how they are completing the task and how it could be improved. Another feature would be to compare closely with the effort required by someone very accomplished in the task to identify what the fundamental differences are.

Organic models encompasses both live and cadaveric models. Within the UK use of live animal tissue to practice surgical techniques is not allowed. However, there still remain many training workshops within Europe and the US that teach surgical techniques on live animal models- for instance laparoscopic cholecystectomy on pigs. This is an expensive way of teaching and animal anatomy can vary from that found in humans. From learning a technical skill point of view, these are arguably the best after learning on real patients. Tactile feedback

should be realistic, and care in movements and how dissections are carried out are important as careless errors will be punished by bleeding or other complications.

Cadaveric models have the advantage of representing accurate anatomy and relations. Cadavers were commonplace in teaching of anatomy to undergraduate students, with regular dissection sessions. Kapadia et al found that cadaver and bench model training were equivalent and superior to text learning alone74. Junior doctors wishing to become a surgeon would often take jobs as demonstrators in the UK- relearning anatomy, preparing prosections and teaching the undergraduates. This provided an excellent opportunity for learning anatomy to a high level and learning careful tissue handling. However, formalin treated tissue behaves nothing like real tissue, and cannot realistically be used to learn surgical procedures. Unfortunately cadavers are being used less frequently in the undergraduate curriculum so there is less opportunity to learn dissection and gain experience in this for both undergraduate and postgraduate demonstrators.