# A Review of Training and Guidance Systems in Medical Surgery
## 3 Methods
### Synthesis of the Selected Works
#### 3.8.3 Endoscopy  
As new technologies arise, endoscopy has been benefited due to its requirements in sensorial-motor skills. By applying technology during surgeries, safety can be enhanced, and harmful or dangerous events can be prevented. This type of technology is usually provided by commercial systems, hardware, and software. [PERSON] et al. evaluated the performance of the Endoscopic Sinus Surgery Simulator (ES3) [59]. ES3 records overall and task-specific scores. For evaluation, it calculates scores using procedure time and accuracy. Penalties are applied to the rating if it detects surgical hazards during the process. ES3 provides guidance and aid in the form of a virtual instructor, which points out mistakes, errors, and misses during the simulation. Moreover, the system supplies users with predefined navigation cues, and it uses target markers during injection and dissection tasks. Another study that analyzes a commercial system for evaluation and guidance during training is the one made by [PERSON] et al. [60]. In this study, the authors tested the LapSim system manufactured by Surgical Science. This endoscopy simulator was used to create a training course. LapSim exercises used in this course were lifting and grasping. These let the authors evaluate both hands' coordination, which is a crucial skill during endoscopy tasks. LapSim lets professors manage classes, students' profiles, and it enables them to generate performance reports. In the area of aid, LapSim gives real-time on-screen cues and off-site reviews based on the user's actions, and the system also uses a virtual helper to provide interactive learning in the simulation. Although commercial systems can provide full tracking, guidance, and assessment tools, they are costly, which makes them no easily affordable for most educational or medical institutions worldwide. Consequently, studies such as the one developed by [PERSON] et al., focus their research to provide a low-cost solution [61]. The authors created an upper endoscopy training system that stores data from user's sessions. The system provides two modes: training and exam modes. On training, the simulator uses an interactive training experience by enabling a helper on the scene. On the other hand, exam mode asks students to take snapshots of the scene, which are evaluated using an SVM. The simulator provides adaptive questions related to the task, that are generated according to the response of the previous one. The system provides user scores based on the pictures, the results from the questionnaire, and the procedure time. Adaptation of commercial stations is another topic researched in endoscopy. It enables institutions that already have invested in market systems to expand its usefulness by replacing preinstalled software on the stations. [PERSON] et al. modified the NeuroVR system (CAE Inc., QC, Canada) to perform endoscopic third ventriculostomy [62]. The authors replaced NeuroVR's original two mirrors and two screens, and they mounted four mirrors and a screen. New simulation software developed using the Blade framework was installed. The authors modeled two tasks--burr-hole position and entry orientation selection and navigation inside the ventricular system. [PERSON] et al. worked closely with end-users, and they noticed that guidance would be a beneficial resource in their simulator. Therefore, they implemented an on-screen advisor. This advisor can tell the user the actions that have to be done during the procedure by displaying a message window. Another area in endoscopy that has been researched focuses on the information provided to doctors during surgery. Visual information on endoscopy is usually shown in a monitor during the operation; however, some studies state that a direct view of the scene provides better performance [117]. [PERSON] et al. conducted a recent study that is centered on this matter [63]. Sixteen participants were divided into two groups, an endoscopic-view group and a direct-view group. They had to ablate three layers of simulated tissue.