**4. Simulation in upper gastrointestinal (UGI) surgery**

There are currently only a limited number of simulators for upper gastrointestinal (UGI) surgery (**Table 4**).

## **4.1 Esophagectomy**

Esophagectomy is a complex multiple-step procedure that is difficult to perform and teach in the operating room. There is currently no simulator for training the entire operation; however, different parts of the operation can be learned on current simulators. *THE* (transhiatal esophagectomy) *GooseMan* simulator allows for training in transhiatal esophagectomies using an intact porcine organ block along with a


*Current Concepts and Controversies in Laparoscopic Surgery*


**Table 4.**

*Simulators for upper gastrointestinal (UGI) procedures.*

plastic torso, an artificial diaphragm, lungs, heart, aortic, and azygous circulation [27]. This model allows for esophageal mobilization and gastric tubularization while simulating hypotension and aortic and azygous hemorrhage. It is reported to cost less than \$200 USD to build. However, this model has not been validated.

A simulation of esophageal anastomosis has been developed with an *ex vivo* porcine model. It allows for the formation of an esophageal anastomosis with staplers and the placement of sutures into the esophageal wall. The model is highly realistic in allowing various types of esophageal anastomosis to be carried out. However, mobilization of esophagus and stomach cannot be carried out. Overall, the participants using this model found it to be realistic and a good method for developing the skills required for esophageal anastomosis [28].

Orringer et al. [26] have described a cervical esophagogastric anastomosis simulator using silicone esophagus and gastric tip allowing for the formation of a stapled anastomosis. In a pilot trial assessing the simulators, seven thoracic surgeons and eight trainees evaluated the model based on fidelity (multi-variable assessment of degree of realism of a simulator) [36]. The participants rated the model low for realism and the trainees rated the closure of the outer anterior layer of the esophagus model as more difficult than the experienced surgeons. However, there were no overall fidelity differences between trainees and experienced surgeons. The participants felt the model would be useful in training to do cervical esophagogastric anastomosis. The overall cost was \$500 USD for the model including single-use disposables.

#### **4.2 Hiatus hernia repair and fundoplication**

The University of North Carolina has developed a porcine organ block, including heart, lungs, esophagus, diaphragm, stomach, duodenum, liver, and spleen mounted in a human mannequin and perfused with artificial blood [17]. Five expert surgeons performed laparoscopic Heller myotomy, Nissen fundoplication, and sleeve gastrectomies. On completion of a survey after performing the procedures, the model was found to be highly realistic in terms of tissue feel and the use of instruments for all three operations. Some of the limitations of this model were the low number of assessments, the vascularization of the model was not realistic, and it is unclear whether training on the foregut simulator transferred to operative performance in real patients.

An artificial reusable model has been developed of the upper abdominal anatomy, with realistic tissue properties for training in laparoscopic UGI procedures, such as Nissen fundoplication [30]. A range of materials from silicone, latex, and thermoplastic was used to create the model. The advantages included a realistic representation of human anatomy, unlimited preservation, reusable parts, and fixed cost of the model. This model, however, has not been validated.

The Toronto lap-Nissen *ex vivo* porcine laparoscopic simulator increases training surgeons' comfort level when performing or assisting with Nissen fundoplication or Heller myotomy [29]. This model simulates an anatomic model of the human upper abdomen using porcine esophagus, diaphragm, stomach, and spleen in a box trainer. The training model was used as a part of a laparoscopic training course. Twenty-five trainees and five consultant surgeons completed a survey after using the model and subjective measures pre- and post-training showed an increase in knowledge and comfort levels in assisting and being the primary surgeon. The advantages of this model include anatomically appropriate position of diaphragm,

and cost-effectiveness given the organs can be obtained from a butcher instead of having an anesthetized animal. It was suggested that the model needs improvement as the stomach is too rigid to wrap around the esophagus.
