Abstract:
Exemplary embodiments of a virtual reality surgical training simulator may be described. A virtual reality surgical training simulator may have a rendering engine, a physics engine, a metrics engine, a graphical user interface, and a human machine interface. The rendering engine can display a three-dimensional representation of a surgical site containing visual models of organs and surgical tools located at the surgical site. The physics engine can perform a variety of calculations in real time to represent realistic motions of the tools, organs, and anatomical environment. A graphical user interface can be present to allow a user to control a simulation. Finally, a metrics engine may be present to evaluate user performance and skill based on a variety of parameters that can be tracked during a simulation.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority from U.S. Provisional Patent Application No. 61/790,573, filed Mar. 15, 2013, and entitled SYSTEM, METHOD, AND COMPUTER PRODUCT FOR VIRTUAL REALITY SURGICAL TRAINING SIMULATOR, the entire contents of which are hereby incorporated by reference. 
     
    
     BACKGROUND 
       [0002]    Simulation is a training technique used in a variety of contexts to show the effects of a particular course of action. Well-known simulators include computer flight simulators used to train pilots or for entertainment and even games like Atari&#39;s Battlezone, which was adapted by the U.S. Army to form the basis of an armored vehicle gunnery simulator. Simulators can range from simpler computer-based simulators configured to receive input from a single input device (e.g. a joystick) to complex flight simulators using an actual flight deck or driving simulators having a working steering wheel and a car chassis mounted on a gimbal to simulate the forces experienced while driving a car and the effects of various steering and command inputs provided through the steering wheel. 
         [0003]    Surgical simulation platforms exist to allow for teaching and training of a variety of surgical techniques and specific surgical procedures in a safe environment where errors would not lead to life-threatening complications. Typical surgical simulation platforms can be physical devices that are anatomically correct models of an entire human body or a portion of the human body (for example, a chest portion for simulating cardiothoracic surgery or an abdomen portion for simulating digestive system surgery). Further, human analogues for surgical training can come in a variety of sizes to simulate surgery on an adult, child, or baby, and some simulators can be gendered to provide for specialized training for gender-specific surgeries (for example, gynecological surgery, caesarian section births, or orchidectomies/orchiectomies). 
         [0004]    While physical surgical platforms are commonly used, physical simulation is not always practical. For example, it is difficult to simulate various complications of surgery with a physical simulation. Further, as incisions are made in physical surgical simulators, physical simulators may require replacement over time and can limit the number of times a physical simulator can be used before potentially expensive replacement parts must be procured and installed. 
         [0005]    Virtual reality surgical simulation platforms also are available to teach and train surgeons in a variety of surgical procedures. These platforms are often used to simulate non-invasive surgeries; in particular, a variety of virtual surgical simulation platforms exist for simulating a variety of laparoscopic surgeries. Virtual reality surgical simulators typically include a variety of tools that can be connected to the simulator to provide inputs and allow for a simulation of a surgical procedure. 
         [0006]    User interfaces for virtual reality surgical simulation platforms often rely on the use of a keyboard and pointing device to make selections during a surgical simulation. Further, graphical user interfaces for virtual reality surgical simulation platforms often present a multitude of buttons that limit that amount of screen space that can be used to display a simulation. Such interfaces can be unintuitive and require excess time for a user to perform various tasks during a simulation. 
       SUMMARY 
       [0007]    Exemplary embodiments of a virtual reality surgical training simulator may be described. A virtual reality surgical training simulator may have a rendering engine, a physics engine, a metrics engine, a graphical user interface, and a human machine interface. The rendering engine can display a three-dimensional representation of a surgical site containing visual models of organs and surgical tools located at the surgical site. The physics engine can perform a variety of calculations in real time to represent realistic motions of the tools, organs, and anatomical environment. A graphical user interface can be present to allow a user to control a simulation. Finally, a metrics engine may be present to evaluate user performance and skill based on a variety of parameters that can be tracked during a simulation. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    Advantages of embodiments of the present invention will be apparent from the following detailed description of the exemplary embodiments. The following detailed description should be considered in conjunction with the accompanying figures in which: 
           [0009]      FIG. 1  shows an exemplary system diagram of a physics engine configured to provide realistic output for a virtual reality surgical simulator. 
           [0010]      FIG. 2  shows an exemplary embodiment of a physics engine configured to provide haptic output from a virtual reality surgical simulator to a connected human machine interface. 
           [0011]      FIG. 3  shows a flow diagram of a method for receiving movement information and transmitting the information to a physics engine. 
           [0012]      FIG. 4  shows a flow diagram of a method for receiving simulated movement information and generating feedback for a user. 
           [0013]      FIG. 5  shows a flow diagram of a method for communicating tactile feedback to a user. 
           [0014]      FIG. 6  shows a system diagram of a virtual reality surgical simulator. 
       
    
    
     DETAILED DESCRIPTION 
       [0015]    Aspects of the present invention are disclosed in the following description and related figures directed to specific embodiments of the invention. Those skilled in the art will recognize that alternate embodiments may be devised without departing from the spirit or the scope of the claims. Additionally, well-known elements of exemplary embodiments of the invention will not be described in detail or will be omitted so as not to obscure the relevant details of the invention. 
         [0016]    As used herein, the word “exemplary” means “serving as an example, instance or illustration.” The embodiments described herein are not limiting, but rather are exemplary only. It should be understood that the described embodiments are not necessarily to be construed as preferred or advantageous over other embodiments. Moreover, the terms “embodiments of the invention”, “embodiments” or “invention” do not require that all embodiments of the invention include the discussed feature, advantage or mode of operation. 
         [0017]    Further, many of the embodiments described herein are described in terms of sequences of actions to be performed by, for example, elements of a computing device. It should be recognized by those skilled in the art that the various sequences of actions described herein can be performed by specific circuits (e.g. application specific integrated circuits (ASICs)) and/or by program instructions executed by at least one processor. Additionally, the sequence of actions described herein can be embodied entirely within any form of computer-readable storage medium such that execution of the sequence of actions enables the at least one processor to perform the functionality described herein. Furthermore, the sequence of actions described herein can be embodied in a combination of hardware and software. Thus, the various aspects of the present invention may be embodied in a number of different forms, all of which have been contemplated to be within the scope of the claimed subject matter. In addition, for each of the embodiments described herein, the corresponding form of any such embodiment may be described herein as, for example, “a computer configured to” perform the described action. 
         [0018]    Referring to exemplary  FIG. 1 , a physics engine for use in a virtual reality surgical simulator may be disclosed. Physics engine  100  may have an interaction calculator  102 , a physical scene description  104 , and one or more object descriptions  106 . In one exemplary embodiment, physical scene description  104  and object descriptions  106  may be computer files accessed by physics engine  100 . Physical scene description  104  may contain a description of each of the one or more objects that can have physical interactions in a simulation. In an exemplary embodiment, physical scene description  104  may contain a description of the organs or soft tissue being operated on and any of the one or more tools that may be inserted into a simulated body for use in the simulated surgical procedure. In some embodiments, one or more physical scene descriptions  104  and one or more object descriptions  106  may be stored in a database, and the appropriate scene description  104  and one or more object descriptions  106  may be loaded into physics engine  100  depending on the surgical simulation to be performed 
         [0019]    Physics engine  100  may perform kinematic, collision, and deformation calculations in real time to represent realistic motions of the tools, organs, and anatomical environment during a surgical procedure. Physics engine  100  may allow the use of multiple geometric models of the same object. In some embodiments, objects may be represented in physics engine  100  by a mechanical model having mass and constitutive properties, a collision model having a simplified geometry, and a visual model having a detailed geometry and visual rendering parameters. In some embodiments, each object may be represented in separate files or data objects. Physics engine  100  may support the addition and removal of objects during the simulation. As objects are added and removed, physics engine  100  may be updated to reflect the changed physical relationships within the simulated anatomical environment and the properties of different surgical tools inserted into the simulated anatomical environment (for example, the flexibility of tubing versus the rigidity of steel cutting or grasping instruments). 
         [0020]    In an exemplary embodiment, each of the organs or soft tissues described in physical scene description  104  may have a corresponding physical object description  106 . Each physical object description  106  may have a volumetric nodal point description  108  and a spherical boundary description  110 . Volumetric nodal point description  108  may have a simplified geometry containing information about the boundaries of an object to be used by interaction calculator  102  to determine the physical behavior of objects in a simulation. In an exemplary embodiment, spherical boundary description  110  may contain information about the volumetric boundary of an object to be used by interaction calculator  102  to detect collisions between objects (for example, collisions between discrete soft tissues or organs or collisions between a surgical tool and soft tissue). 
         [0021]    Referring now to exemplary  FIG. 2 , a system for providing haptic feedback from collision and interaction calculations generated by physics engine  100  may be disclosed. A human machine interface  200  may be connectively coupled to a virtual reality surgical simulator. Human machine interface  200  may have an input/output processor  202  configured to receive input from a virtual reality surgical simulator and transmit movement outputs from human machine interface  200  to a connected virtual reality surgical simulator. Human machine interface  200  may further have a plurality of hardware elements  204 , each of which may have one or more actuators  206  configured to provide physical feedback through one of the plurality of hardware elements  204 . Hardware elements  204  may be shaped in any desired form; in some embodiments, hardware elements  204  may be shaped in the form of the surgical instruments to be used in a particular surgical procedure to impart a sense of realism to the simulation. Interaction calculations generated by physics engine  100  may include an amount and direction of force a collision with soft tissue or an organ may impart on a surgical tool. Physics engine  100  may transmit force information to human machine interface  200 , and input/output processor  202  may actuate one or more appropriate actuator  206  to impart the appropriate amount of force in the calculated direction on one or more hardware element  204  to give a user real-time tactile feedback about the precise location of a surgical tool being used in a simulation. 
         [0022]    Referring generally to exemplary  FIGS. 3-5 , a method of providing haptic feedback in a surgical simulator may include receiving movement information from a user and transmitting it to a physics engine, performing physics calculations, and communicating feedback information to a user through a tactile medium. 
         [0023]    Exemplary  FIG. 3  shows a flow diagram of a method  300  of receiving movement information and transmitting the information to a physics engine. An exemplary embodiment of method  300  may be performed by a human machine interface, for example one as described above and as shown in exemplary  FIG. 2 . In step  302 , hardware movement information may be received. Hardware movement information may be generated by a user utilizing one or more hardware elements. In some embodiments, hardware elements may be constructed to have handholds substantially similar to surgical implements, or as desired, with actuators to detect movement and generate an electronic signal corresponding to the physical movement. Hardware movement information may include the amount of force and in which direction it is applied by a user. 
         [0024]    In step  304 , the hardware movement information may be transmitted to a processor. In step  306 , the processor may convert the hardware movement information to simulated movement information. In some exemplary embodiments, analog hardware movement information may be converted to digital simulated movement information. In a final step  308 , the simulated movement information may be transmitted to a physics engine. The physics engine may be a processor coupled with a memory which may be configured to accept simulated movement information, perform physics calculations, and provide feedback. 
         [0025]    Exemplary  FIG. 4  shows a flow diagram of a method  400  of receiving simulated movement information and providing feedback to a user. An exemplary embodiment of method  400  may be performed by a physics engine, for example one as described above and as shown in exemplary  FIG. 1 . In step  402 , simulated movement information may be received. The simulated movement information may have been generated by a user through a human machine interface, for example as described above and shown in  FIG. 3 . 
         [0026]    In step  404 , physics calculations such as kinematic, collision, and deformation calculations may be performed. To perform step  404 , a scene description, an object description, and an interaction calculator may be utilized. A scene description may contain a description of each of the one or more objects that can have physical interactions in a simulation, for example the locations and orientations of organs and tools in a surgical simulation. Each object within the simulation may have an object description. Each object description may include information describing the object&#39;s shape, size, and physical properties. An interaction calculator may determine the simulated forces present if a simulated collision is determined to occur. In step  404 , the collision and deformation calculations may alter the scene description and object description. 
         [0027]    Step  404  results in generating feedback information. In step  406 , feedback information is transmitted via a human machine interface, for example the same interface used to generate the original hardware movement information received in step  302 , as described above. In step  408 , feedback information is sent a processor system. The processor system may further be coupled to a visual rendering engine which may provide visual feedback via a monitor to the user. The processor system may in addition be coupled to a metrics engine, which may record the simulated movements made and determine how well a simulation was completed. 
         [0028]    Exemplary  FIG. 5  shows a flow diagram of a method  500  of communicating tactile feedback to a user. An exemplary embodiment of method  500  may be performed by a human machine interface, for example one as described above and as shown in exemplary  FIG. 2 . In step  502 , feedback information is received. Feedback information may have been generated by a simulation, for example, a physics engine as described above and as shown in exemplary  FIG. 1 . In step  504 , the feedback information is converted to one or more actuator commands. In some exemplary embodiments, an output processor may interpret digital feedback information into one or more actuator commands. In step  506 , the actuator command is transmitted to a hardware element. The hardware element may contain one or more actuators. In step  504 , a processor may determine which of a plurality of actuators situated on one or more hardware elements should receive the actuator command. In some exemplary embodiments, the one or more hardware elements may be constructed to have handholds substantially similar to surgical implements, or as desired, and may be held by a user. In response to the transmittal of an actuator command in step  506 , the one or more actuators may exert a force on the one or more hardware elements, thus providing haptic feedback to the user. 
         [0029]    Referring to exemplary  FIG. 6 , physics engine  100  and human-machine interface  200  may be parts of a virtual reality surgical simulator  600 . Physics engine  100  may be communicatively coupled to a processing system  602 . Processing system  602  may further be communicatively coupled to a rendering engine  604 . Rendering engine  604  may render visuals of the simulation, for example to provide visual feedback to a user. Processing system  602  may also be communicatively coupled to a metrics engine  606 . Metrics engine  606  may determine how well a simulation was completed. Virtual reality surgical simulator  600  may also include an input device  608  and an output device  610 . Input device  608  and output device  610  may be two separate devices or a single integrated device, as desired. In some exemplary embodiments, input device  608  may allow a user to log in, access records of simulations, and select a simulation to perform. In some exemplary embodiments, output device  610  may provide visual feedback to a user, for example, an image of a simulated surgery or the calculated records of completed simulations. 
         [0030]    The foregoing description and accompanying figures illustrate the principles, preferred embodiments and modes of operation of the invention. However, the invention should not be construed as being limited to the particular embodiments discussed above. Additional variations of the embodiments discussed above will be appreciated by those skilled in the art. 
         [0031]    Therefore, the above-described embodiments should be regarded as illustrative rather than restrictive. Accordingly, it should be appreciated that variations to those embodiments can be made by those skilled in the art without departing from the scope of the invention as defined by the following claims.