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What makes a simulator great?

“A surgeon or endoscopist should be able to work with instruments in an environment that feels just like that of working on a real patient. There should not be the feeling of a game or artificial environment. Only 3D Systems has worked closely with physicians to develop a continuous improvement of a simulated environment.”
Jeffrey Ponsky (26)  [26]

What is a surgical simulator? 

Basically the concept of a surgery simulator is really simple. The idea is to use these simulators to  help doctors and students to train for a surgery but excluding a patient or an animal or whatever may be used to perform a surgery. So a surgical simulator is a machine, training medical staff in a realistic way so they can learn the technical skills they need to know during a specific surgery. This kind of method, obviously it is not similar to the traditional one used to train doctors and students. Simulation can be a standardized and safe method for training and assessing surgeons and also an easier way to learn the appropriate skills they need. Earlier in time, training and learning was more difficult including that the surgeries were made in real patients and the pressure of patient safety was high. Of course, this is only one of the reasons why surgical simulators, due to technology advancement is safer and with a higher priority. [1], [2]. What we explained above, is also called surgical training. 

Surgical Training

The past three decades have seen a rising interest in the use of simulation for the purposes of training doctors, quality of care, and patient safety. The use of this method to train has become important since it helps not only the ones who are being trained but also the trainers. Since they are not experimenting with real people, it doesn't take as much time as a traditional training, they can make mistakes and see what happens, answer the "what if?" question, learn and reflect for the different situations and make sure to learn from mistakes and not only, so they do better when it comes to a real patient. These simulators are best used to teach skills as  eye–hand coordination and the ability to perform three dimensional actions using a two-dimensional screen as a guide. Eye–hand coordination is improved because the simulation can give both visual feedback, by way of a screen, as well as tactile feedback that simulates the manipulation of organs and tissue. Laparoscopic surgery is one of the procedures that surgeons are being trained using these surgical simulators using virtual reality. In this kind of procedure, the simulator uses a computer screen displaying a three-dimensional graphic of the organs being operated on. Various surgical tools or gloves are connected to motion sensors and haptic or tactile feedback mechanisms where the user can physically feel the difference in simulated tissue and organs.  Virtual reality simulators have been used to allow experts to plan complicated operations and assess perioperative risks. The idea to use virtual reality to simulate medical procedures came from the video games industry. [1], [2], [3], [4], [5]

Laparoscopic trainer [7]

           [6]                                                                                                                                                          


Surgical Rehearsal Platforms

Surgical rehearsal platforms are surgical simulators that offer the opportunity to rehearse a procedure prior to entering the operative suite. The main idea of a surgical rehearsal platform is to transform the patient's given CT and MRI images into a realistic, interactive, 3D computer-based model of that patient. This SRT allows surgeons to plan and rehearse microsurgical techniques for clipping intracranial aneurysms and extracting brain tumors. Using standard scanned images from any patient, the Platform generates 3D images that enable the accurate modeling of interactions between life-like tissue and surgical instruments. The tissue responds "naturally" to actions taken by the surgeon, thus allowing accurate pre-surgery planning and rehearsal. Obviously these SRT are being developed to use for different surgeries, mostly for those which are more complicated than other ones like for example a brain aneurysm or any kind of neurosurgery and other surgery procedures too where surgeons find it harder to procced, being completely confident for the next steps. The SRP involves preoperative rehearsal and planning. Similarly to the CT/MRI studies, the SRP will be available for surgeons during the surgery for evaluation of optional surgical approaches. [8], [9], [11], [12]

During a brain surgery using SRT (© http://case.edu/medicine/neurosurgery/)


SRT (Surgical Theater) [9]

Surgical Simulator Brain Surgery [10] (All rights reserved to CBS Morning Show)




Surgical Simulator Parts 

Surgical simulators have been a big achievement when it comes to training doctors and surgeons. Training by simulation, whether virtual, hybrid, or real, allows the surgeon to rehearse, learn, improve or maintain their skills in a safe and stress free environment. With that being said we also need to know that training by simulation it is not easy and it requires a professional medical staff with a experience before hand so they have the idea of the body anatomy, vessels etc and know the general traditional procedure of any kind of surgery. No matter how advanced or complex the simulation tool, it is of little use without a knowledgeable educator and a well-prepared curriculum. Obviously,  the simulator (s) and their structure also plays a huge role. The surgeons and the trainers  need to feel comfortable using the simulator and understanding how the "machine" works. So basically, in order to achieve high quality results,  the simulators consist into some important elements:  [14]

  1. Volume rendering 
  2. Model response 

  3. Haptics 

Volume rendering is a set of techniques used to display a 2D projection of a 3D discretely sampled data set, typically a 3D scalar field. The main idea is to create 3D models based on imaging modalities like CT or MRI so they can be used for surgical simulators. As commonly implemented, 3D volume rendering takes the entire volume of data, sums the contributions of each voxel along a line from the viewer's eye through the data set, and displays the resulting composite for each pixel of the display. Incorporation of information from the entire volume can lead to greater fidelity to the data; however, much more powerful computers are required to perform volume rendering at a reasonable speed. Differences in implementation of various volume rendering techniques result in varying quality and utility among applications. In order to create valid 3D generic models from 2D image stacks, more attention should be paid to two essential steps - image segmentation and image registration. Obviously, this step is really important since the 3D anatomical models that need to be created must be very accurate to the real model. Beside that, the simulator or better to say it's software must be careful to "catch" every motion and most of deformations even though it must not be allowed to just "create" a deformation it doesn't exist or that physically can't occur. The other part is haptic, or in a simple way the interaction between the user and the simulator. It is important for surgeons to be trained for tasks that require hand-eye coordination, since this is very important when it comes to surgery. In this case it is crucial for the surgeon to sense the parts of the body as in reality and to put the exact amount of pressure into the simulator. [15], [16], [17]

Simulator examples

  • Neuro Touch/ NeuroVr

    NeuroTouch, the prototype simulator developed by Canada’s National Research Council (NRC) and several other research groups, gives surgeons a dry run in virtual reality before entering the operating room, potentially reducing mistakes. First, patient data from functional magnetic resonance imaging (fMRI) is rendered into a 3-D, high-resolution model of an individual’s brain. After the model is loaded into the system, doctors can touch and manipulate tumors and other virtual objects on screens in real time using a physical instrument resembling a scalpel. The instrument has six degrees of freedom and re-creates the force-feedback of the real tool and the varying resistance of tissue in brain regions with differing toughness. The simulation software engine runs 3 processes for computing graphics, haptics, and mechanics. Training tasks were built from magnetic resonance imaging scans of patients with brain tumors. [18], [19], [20], [21]

    NeuroTouch: A Neurosurgery Simulator for Training  © CAE  [23]                             NeuroVR Surgical Simulator © CAE [24]

                                    

  • LapVr Surgical Simulator

    As can be understood from the name the LapVr it is a surgical simulator for laparoscopic training. Lately, this is another example where surgical simulators are successful. LapVR gives learners the opportunity to develop proficiency in techniques such as suturing, knot tying and loop ligation as well as some frequently performed laparoscopic surgeries like gall bladder removal and tubal occlusion for risk-free learning before they touch their first patient. [22]

    LapVr surgical simulator © CAE [25]




Bibliography:    

  1. https://en.wikipedia.org/wiki/Surgery_simulator
  2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4337453/
  3. Van der Meijden OA, Schijven MP. The value of haptic feedback in conventional and robot-assisted minimal invasive surgery and virtual reality training: a current review. Surg Endosc. 2009;23(6):1180–1190.
  4. Torkington J, Smith SG, Rees BI, Darzi A. Skill transfer from virtual reality to a real laparoscopic task. Surg Endosc. 2001;15(10):1076–1079.
  5. https://www.google.com/patents/US8469716
  6. http://www.sciencedirect.com/science/article/pii/S1743919114009741
  7. http://bit.ly/2sgljCR
  8. http://www.neurosurgic.com/index.php?option=com_content&view=article&id=2013:surgical-rehearsal-platform&catid=176:neurosurgical-news&Itemid=639
  9. https://www.youtube.com/watch?v=N08VfC9BbL
  10. https://www.youtube.com/watch?v=xeR92MbiFk8
  11. http://thejns.org/doi/abs/10.3171/2016.1.JNS152576?journalCode=jns
  12. http://case.edu/medicine/neurosurgery/
  13. https://clinicaltrials.gov/ct2/show/NCT02099318
  14. http://www.anthempress.com/surgical-simulation
  15. http://pubs.rsna.org/doi/full/10.1148/radiographics.19.3.g99ma14745
  16. https://en.wikipedia.org/wiki/Volume_rendering
  17. https://whatis.techtarget.com/definition/haptics
  18. http://in-training.org/neurotouch-advances-field-surgical-simulation-8708
  19. https://caehealthcare.com/surgical-simulation/neurovr
  20. http://wolterskluwer.com/company/newsroom/news/health/2012/09/virtual-reality-simulator-helps-teach-surgery-for-brain-cancer-reports-neurosurgery.html
  21. http://neurosim.mcgill.ca/
  22. https://caehealthcare.com/surgical-simulation/lapvr
  23. https://www.youtube.com/watch?v=XOElPpaHHe8
  24. https://vimeo.com/190588397
  25. https://www.youtube.com/watch?v=UBX1SDKtuMw
  26. http://simbionix.com/simulators/


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