Patent Publication Number: US-2023149085-A1

Title: Surgical simulation device

Description:
TECHNICAL SCOPE OF THE INVENTION 
     The present invention relates to the field of medical instruments and equipment. More particularly, the invention relates to a device for surgical simulations. 
     TECHNICAL BACKGROUND 
     It is known in the field of medicine to offer training devices to trainee surgeons. Trainees can of course train on deceased bodies, but these are limited in number. Trainees can also train on living patients under the supervision of a senior surgeon, but this practice poses a risk to the patient. It is therefore essential to provide systems to free surgical learning from the availability of deceased bodies or patients. 
     Many examples of such systems already exist in the state of the art, as illustrated, for example, in EP 1746558 B1, and WO 2019204615 (A1). 
     Document EP1746558 B discloses a system for simulating a surgical operation, by a user, on a body, simulated with at least two real instruments. The system comprises a longitudinal track and a plurality of carriages movable along said track. Each carriage has clamping means and means for rotating and longitudinally moving said real instruments. The system also comprises feedback means for receiving and transmitting, to the user&#39;s hand, a feedback force from said real instrument with respect to the simulation characteristic, means for recognising a real instrument to be inserted into said clamping means, whereby said real instrument can be fixed within said clamping means to be moved longitudinally and rotated by the user. 
     Document WO 2019204615 (A1) discloses an apparatus comprising an endoscopy device, and a tracking device adapted to work with a three-dimensional tracking system to track the location and orientation of the endoscopy device in three dimensions in a simulated operating room environment. The apparatus also includes a physical model of a patient&#39;s head comprising hard and soft components, and the endoscopy device is configured to be inserted into the physical model to provide haptic feedback of the endoscopic surgery. 
     Both documents disclose surgical training devices by combining a mechanical system (surgical instruments and/or training consoles) with a sensor system and a display system. The sensors determine the positioning of the instruments used by the operator in relation to the elements of the training console. Data is displayed on a display system to assist the surgical trainee. However, none of these devices allow for real immersion. The conditions of the operating theatre are not reproduced and the trainee cannot experience all the sensations of an operating theatre procedure. The prior art disclosures lack a virtual component to the simulation, in order to significantly approximate the operating conditions in the operating room. The only way to reproduce these conditions in a relevant way is to immerse the operator in a virtual world, while allowing him to manipulate real surgical instruments in order to prepare him as well as possible for the real conditions of the operating room. 
     Virtual reality is also used to accompany a surgeon during a surgical procedure, as for example illustrated by WO 2017114834 (A1). 
     Document WO 2017114834 (A1) discloses a control unit provided for a surgical robot system, comprising a robot configured to operate a surgical tool on a patient. The control unit includes a processor configured to transmit live images acquired from the patient to a virtual reality (VR) device for display. The unit processes the input data received from the VR device to determine a target on the patient and determine a path for the surgical tool to reach the target based on the live images and the processed input data; and to transmit control signals to cause the robot to guide the surgical tool to the target via the determined path. 
     However, when accompanying a surgeon during an operation, it is not a question of recreating the conditions of the operating theatre in order to familiarise a beginner. 
     The prior art disclosures do not allow the user to manipulate real surgical instruments simultaneously in the physical world and in a virtual world reproducing the operating conditions in the operating room. 
     It is to these disadvantages that the invention more particularly intends to remedy by proposing a surgical simulation device combining a virtual world with the use of real surgical instruments. 
     SUMMARY OF THE INVENTION 
     This is achieved in accordance with the invention by means of a surgical simulation device, comprising:
         a computing unit,   a real surgical instrument, and   a virtual surgical instrument connected to the computing unit,   an electronic system comprising an electronic card and at least one sensor, the electronic system connecting the real surgical instrument to the computing unit, the electronic card and the at least one sensor being integrated into the real surgical instrument by means of at least one specific interface part.       

     The invention is characterised in that:
         the real surgical instrument with the electronics has substantially the same weight as the corresponding functional surgical instrument   the real surgical instrument corresponds to a functional surgical instrument, the functional surgical instrument being intended to be manipulated within the framework of a surgical operation, the functional surgical instrument comprising at least one functional element, the real surgical instrument comprising the same functional element, the at least one functional element being able to be activated according to at least two distinct operating states,   the virtual surgical instrument has the same geometrical characteristics as the real surgical instrument and has a virtual functional element similar to the functional element of the real surgical instrument,   the virtual functional element of the virtual surgical instrument is adapted to be activated in the same operating states as the functional element of the real surgical instrument, and   the operating state of the virtual functional element of the virtual instrument is adapted to be aligned, in real time, with the operating state of the functional element of the real surgical instrument.       

     Thus, this solution achieves the above-mentioned objective. In particular, providing instruments with at least one sensor and linking each of them to a virtual twin that the operator has in his virtual field of view, significantly increases the realism of the training and almost identically reproduces the operating conditions in an operating theatre. The activation by the operator of the mechanical or electronic functionalities of the real surgical instrument triggers an identical action in the virtual world, i.e. the operating state of the real surgical instrument is instantly reproduced in the virtual world by the virtual surgical instrument. Furthermore, this surgical simulation device allows the connection of a wide variety of surgical instruments (mechanical and/or electronic, small and/or large, rigid and/or flexible). 
     The surgical simulation device according to the invention may comprise one or more of the following features, taken alone or in combination with each other:
         the at least one sensor of the electronic system may constitute a functional element of the real surgical instrument,   the at least one sensor of the electronic system may be for measuring a mechanical capacity of a functional element of the actual surgical instrument,   the at least one sensor of the electronic system may be intended to measure a relative movement of a functional element of the real surgical instrument with respect to an original position,   the real surgical instrument provided with the electronic system may have dimensions, shapes, and a centre of mass substantially identical to those of the functional surgical instrument,   the electronic card, the at least one sensor and the at least one specific interface piece are integrated into the real surgical tool in replacement of at least one electronic component of a set of electronic components of the functional surgical instrument,   the virtual surgical instrument may be adapted to be viewed by the operator on a viewing device connected to the computing unit,   the real surgical instrument may be provided with a haptic device so as to be able to simulate, for the operator, an interaction with a predefined body, of a nature and positioning determined by the computing unit,   a virtual equivalent of the predefined body is adapted to be visualized, by the operator, on the display device,   the real surgical instrument may be provided with a sound feedback system,   the real surgical instrument may be provided with a spatial localization system so that the computing unit can determine, at each instant, the positioning of the real surgical instrument in space with respect to a predefined origin.       

    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       Further features and advantages of the invention will become apparent from the following detailed description, for the understanding of which reference is made to the attached drawings in which: 
         FIG.  1    is a generalized schematic view of the simulation device according to the present invention, 
         FIG.  2    is a perspective view of a first embodiment of a real surgical instrument according to the invention, 
         FIG.  3 A  is a perspective view of a first specific interface part according to the invention, 
         FIG.  3 B  is a perspective view of the interface piece of  FIG.  3 A  integrated with a surgical instrument according to the embodiment of  FIG.  2   , 
         FIG.  4 A  is a perspective view of a second specific interface part according to the invention, 
         FIG.  4 B  is a perspective view of the interface piece of  FIG.  4 A  integrated with a surgical instrument according to the embodiment of  FIG.  2   , 
         FIG.  5    is a perspective view of a virtual surgical instrument according to the invention, 
         FIG.  6 A  is a perspective view of a virtual operating theatre at the time of starting an operation, 
         FIG.  6 B  is a perspective view of the operating theatre of the previous figure during the operation, 
         FIG.  7 A  is an illustration of a virtual screen of the virtual operating theatre of  FIGS.  6 A and  6 B , during operation, more particularly,  FIG.  7 A  is an illustration of a virtual screen in the virtual operating theatre providing access to an interior view of a virtual patient, 
         FIG.  7 B  is an illustration of the virtual screen of the previous figure at the end of the operation, 
         FIG.  8 A  is a perspective view of a second example of a real surgical instrument according to the invention, 
         FIG.  8 B  is a perspective view of the embodiment of the previous figure, in which the specific interface piece is open. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the present application, the term “to integrate” is used in the dictionary sense of placing something in a set in such a way that it appears to belong to it, that it is in harmony with the other elements of the set. To integrate something into something means to incorporate it, to make it part of a whole. 
     In the present application, the term “sensor” refers to a device that transforms the state of an observed physical quantity into a usable quantity, such as, for example, an electric voltage, a mercury height, or the deflection of a needle. It is noted that a is at least constituted by a transducer. 
     As schematically shown in  FIG.  1   , a surgical simulation device  10  according to the present invention comprises:
         a real surgical instrument (surgical instrument)  12  intended to be manipulated by an operator,   a computing unit  14 ,   an electronic system  16  comprising an electronic card  18  and at least one sensor  20   a ,  20   b ,  21 ,   a virtual surgical instrument  22  connected to the computing unit  14 .       

     The real surgical instrument  12  is derived from a functional surgical instrument intended to be manipulated in a surgical procedure. Thus, even though the real surgical instrument  12  is not functional in an operating room setting, it reproduces substantially the same physical sensations as a functional instrument when manipulated by an operator in the context of the present invention. 
     The virtual surgical instrument  22  is made visible to the operator by projection onto a display device  24 . 
     In this case, the operator may be a trainee surgeon. 
     The display device  24  is, for example, a virtual reality headset. The operator puts on the headset to perform the surgical simulation. 
     Real Surgical Instrument 
     The electronic system  16  connects the surgical instrument  12  to the computing unit  14 . The electronic system  16  is integrated with the surgical instrument  12 . The electronic system  16  may be integrated into any type of surgical instrument  12 , including, for example, foot switches arranged around machines typically present in an operating room (such as an ultrasound scanner, a milling machine or bed), a photopolymerization lamp or a milling speed control unit for example. Furthermore, the electronic system  16  is transparent in size, shape, weight and centre of mass to the operator handling the surgical instrument  12 . 
     The electronic card  18  of the electronic system  16  may for example be a board of the Arduino®, Teensy®, MBed® type. This electronic board  18  can communicate with or without wires (for example according to BLE or WIFI protocols) with the computing unit  14 . This computing unit  14  may, for example, be a remote computer or a microcontroller comprising an arithmetic and logic unit and a memory. The electronic card  18  may, for example, be powered by a rechargeable battery (Li—Po, Ni-MH, Li-Ion . . . ), or by a battery. The electronic card  18  also allows direct feedback to the operator on the status of the electronic system  16  of the surgical instrument  12  by means of a multi-coloured LED (for example to indicate that the device  10  is switched on, that the electronic system  16  is well connected to the computing unit  14 , that the battery level is low, that the sensors  20   a ,  20   b ,  21  are functional, etc.) without having to start a simulation. 
     This electronic card  18  has digital and analogue inputs and outputs to retrieve, in real time, information from the sensors  20   a ,  20   b ,  21  integrated in the surgical instrument  12 . Each sensor  20   a ,  20   b ,  21  collects its own functional information. As shown in  FIG.  2   , all sensors  20   a ,  20   b ,  21  are integrated with the surgical instrument  12 . 
     In the case of the present invention, the electronic system  16  comprises three types of sensors  20   a ,  20   b ,  21 : two types of so-called original sensors (a set of primary original sensors  20   a , and a set of secondary original sensors  20   b ), and one type of so-called additional sensors  21 . The primary and secondary original sensors  20   a ,  20   b  are elements present on the functional surgical instrument  12  as marketed and used by practitioners in an operating theatre. These original primary and secondary sensors  20   a ,  20   b  are disconnected from their basic electronics resulting from their industrial processing and are then integrated into the electronic system  16  of the surgical simulation device  10 . 
     In particular, the original primary and secondary sensors  20   a ,  20   b  each constitute a functional element  26  of the surgical instrument  12 . A functional element  26  is an element required for the proper operation and/or handling of the surgical instrument  12 . Each functional element  26  of the real surgical instrument  12  is identical to the functional element  26  of the corresponding functional surgical instrument. A functional element  26  may be mechanical or electronic. Classically, each functional element  26  may be activated in at least two distinct operating states. This will be explained further below. A functional element  26  may also be primary  26   a  or secondary  26   b . A surgical instrument  12  may thus comprise one or more primary functional elements  26   a  (electronic or mechanical) and one or more secondary functional elements  26   b  (electronic or mechanical). A primary functional element  26   a  may, for example, take the form of an activation handle, button, lever, or touchpad, and it enables the surgical instrument  12  to be operated, activated, and/or controlled, etc. Thus, each primary original sensor  20   a  forming a primary functional element  26   a , allows the computing unit  14  to retrieve an operator action on the surgical instrument  12 . The operator performs this action during a surgical simulation for surgical purposes, such as coagulating a vessel, or orienting the effector of the surgical instrument  12 . Each secondary original sensor  20   b  forming a secondary functional element  26   b , in turn, provides feedback on the operating status of the surgical instrument  12 . A secondary original sensor  20   b  may, for example, take the form of a buzzer or an LED to, for example, indicate to the operator that a coagulation system is ready or that the surgical instrument  12  is at a certain load level. 
     Independent of the original sensors  20   a ,  20   b , the additional sensors  21  are added to the functional surgical instrument  12  and are therefore not required for the proper functioning/use of said instrument  12 . Each additional sensor  21  is used to measure:
         a mechanical capacity of a primary functional element  26   a  of the actual surgical instrument  12 , and/or   a relative movement of a primary functional element  26   a  of the actual surgical instrument  12  with respect to an original position of said primary functional element  26   a,      an orientation of a primary functional element  26   a  relative to an original position of said primary functional element  26   a,      an ambient or internal magnetic field,   an orientation of a primary functional element  26  relative to another primary functional element  26 ,   a relative position of the surgical instrument  12  in space with respect to a defined reference frame.       

     An IMU (inertial measurement unit) may, for example, forms an additional sensor  21 . 
     The electronic system  16  can be added to different categories of surgical instruments  12  in a wide range of applications and in all surgical specialties. Classically, two types of functional surgical instruments are considered:
         complex surgical instruments,   mechanical surgical instruments.       

     Complex functional surgical instruments can be electronic and/or mechanical. They may therefore have a wide variety of mechanical and electronic functional elements  26 . These mechanical functional elements  26  may take the form of mechanical actuators such as buttons, triggers, activation handles P (see  FIG.  2   ), knobs, dimmers, etc. The mechanical functional elements  26  are primary functional elements  26   a . They can be operated by means of a motor or by direct action of the operator. A complex functional surgical instrument also has electronic functional elements  26  such as secondary functional elements  26   b  such as an LED, for example. Where a complex functional surgical instrument is electronic, it is usually provided with a battery or is connected to an external machine in the operating theatre to enable it to be powered. 
     The system&#39;s electrical power is provided by a 12V/3 A power supply (not shown). The data is transmitted by a wired means of communication (USB 2.0, Ethernet) or by a non-wired means of communication (Wifi, Bluetooth, . . . ). 
     Specifically, the signal processing performed from each real surgical instrument  12  produces a real-time effect in the virtual reality simulation. Thus, each virtual surgical instrument  22 , as a virtual twin, moves and reacts identically to its real model. Each real surgical instrument  12  has a unique identifier which allows the values received to be associated with the corresponding virtual surgical instrument  26 , i.e. the correct virtual twin. Each real instrument  12  thus connects to the simulation (TCP, UDP, serial) when it is switched on. Each real instrument  12  then sends its data at a defined frequency to the computing unit  14 . 
     The connection is made between the computing unit  14  and each real surgical instrument  12  via a protocol that can be point-to-point (Unicast) or broadcast (Broadcast or Multicast for example). In all modes, the simulation acts as a data server. 
     The example in  FIG.  2    illustrates the case of a cauteriser. 
     Mechanical functional surgical instruments do not have electronic functional elements but only mechanical functional elements (primary functional elements  26   a ). These include surgical retractors, scissors, forceps and needle holders or more complex mechanical systems such as the AMIS® system by Medacta for hip replacement. 
     As already indicated, each real surgical instrument  12  of the present invention corresponds to a functional instrument and each functional element  26  of the functional surgical instrument corresponds to a functional element  26  of the real surgical instrument  12 . Each functional element  26  of the real instrument  12  may be activated, exactly like the corresponding functional element  26  of the functional instrument, in at least two distinct operating states. The sum of the operating states of each of the functional elements  26  of the real surgical instrument  12  provides the operating state of the real surgical instrument  12  itself. For a complex surgical instrument  12 , for example, a functional off state and a functional on state can be distinguished. The energised functional state can itself be divided into a resting functional state (the operator does not use the instrument  12 ) and an activating functional state (the operator activates the instrument  12 ). Depending on the surgical instruments  12 , there may be several functional states of activation, for example if the surgical instrument  12  has a primary functional element  26   a  that can adopt several speeds, such as the rod T of the surgical instrument  12  of the example shown in  FIG.  2   . For a mechanical surgical instrument  12 , a distinction may, for example, be made between an open functional state and a closed functional state (in the case of forceps, or scissors, for example). 
     Taking the example shown in  FIG.  2   , a secondary sensor  21  may for example measure:
         the rotation of a shaft T of the actual surgical instrument  12 ,   a degree of closure of an activation handle P.       

     Note that the rod T and the activation handle P are each a primary functional element  26   a.    
     The challenge around the sensors is twofold: for the original sensors  20   a ,  20   b  the challenge is to disconnect the original electronics to connect it to the electronic system  16  without altering the original functioning of the sensor  20   a ,  20   b , and, for the additional sensors  21 , the challenge is to add them without disturbing the functioning of the surgical tool  12 . 
     In addition to complex or mechanical surgical instruments  12 , the electronic system  16  may be integrated into a control box present in an operating theatre. This may, for example, be a cold light control box for endoscopic cameras or the control panels of an anaesthesia machine. It is thus possible to recover the actions of a user external to the simulation but present at the operator&#39;s side to reproduce his actions in the simulation. For example, in the case of the use of an endoscopic camera in a surgical simulation, it becomes possible to ask an assistant to adjust the intensity of the light of an endoscopic camera while the operator is performing the surgical simulation. To be able to do this, it is necessary to know the degree of light sent by the endoscopic camera and to connect the light block to the simulation. This same type of situation is found in a simulation during which CO 2  is classically injected into the abdominal wall of a patient before the introduction of the tools: indeed, by connecting the CO 2  injector to the electronic system  16 , it becomes possible to ensure flow management along the operation and the operator can be accustomed to regularly checking the pressure level, for example. 
     The notion of a complex surgical instrument  12  covers certain surgical robots such as, for example, a robotic assistance platform handling console which is increasingly used by practitioners. 
     In the example shown in  FIGS.  2  and  3 B , the rotation of the rod T of the surgical instrument  12  is transmitted via a secondary sensor  21  in the form of an infinitely rotating encoder  28 . Generally speaking, an encoder is a hardware or software component that transforms information into a code. A rotational encoder typically comprises a light source, a disc with holes at regular intervals rotating around an axis and an optical sensor. Each time light passes through one of the holes in the disc, an electrical signal is sent. By collecting the signal that passes through each disc, it is possible to know in which direction the axis rotates and by how many degrees. The more holes the disc has, the more precise the angle. In this case, the encoder shaft  281  is coupled to the rod T of the surgical instrument  12 . Thus, when the rod T is activated (i.e. rotated), it drives the shaft of the encoder  28 . This shaft  281  drives the perforated disc  282  which gives information about the angle of rotation of the rod T. 
     In the example shown in  FIGS.  2  and  4 B , the degree of closure of the activation handle P is transmitted by a secondary sensor  21  which may, for example, take the form of a rotating or sliding variable resistor (potentiometer)  29  or a force sensor. In general, a type of variable resistor with three terminals, one of which is connected to a slider moving over a block of variable resistor terminated by the other two terminals, is called a potentiometer. This system makes it possible to collect, between the terminal connected to the cursor and one of the other two terminals, a voltage which depends on the position of the cursor and the voltage to which the variable resistance block is subjected, the two terminals corresponding to the maximum and minimum values of the variable resistance block. In the present case, the slider  291  of the linear potentiometer  29  is coupled to the activation handle P. Thus:
         when the activation handle P is actuated, the slider  291  of the potentiometer  29  is, along the variable resistance block  292 , displaced in an actuation direction and this displacement causes the resistance of the potentiometer  29  to vary in that direction,   when the activation handle P is released, a spring integrated in the actual surgical instrument  12  pushes the activation handle P back to its original state (open) and the slider  291  of the potentiometer is, along the variable resistance block  292 , driven in the other direction.       

     In this way, the minimum and maximum values that can be reached when the activation handle P is opened or closed are known and, by means of a cross product, the percentage of opening or closing of said activation handle P is accessed. 
     It can be seen from  FIGS.  2 ,  3 B and  4 B  that the electronic card  18  and the sensors  20   a ,  20   b ,  21  are integrated into the surgical instrument  12  by means of at least one specific interface part  30 . Each specific interface part  30  is obtained by 3D printing. 
     In the case of the example illustrated in  FIGS.  2 ,  3 A and  3 B , the connection between the encoder  28  and the rod T of the surgical instrument  12  is enabled by a specific interface piece  30 . This specific interface piece  30  is illustrated in  FIG.  3 A . The specific interface piece  30  of  FIG.  3 A  is in two parts: a first part  301  intended to be glued to the rod T of the surgical instrument  12 , and a second part  302  intended to be glued to the shaft of the encoder  28 . The shaft of the encoder  28  can be driven by the rod T via a coding system. The specific dimensioning and geometry of the specific interface part  30  linked to the encoder  28  thus makes it possible to ensure that the encoder  28  is driven by the rod T of the surgical instrument  12  without hindering the travel of the rod T during the operation of the surgical instrument  12 . 
     In the case of the example illustrated in  FIGS.  2 ,  4 A and  4 B , the coupling between the activation handle P of the surgical instrument  12  and the potentiometer  29  is also guaranteed by another specific interface piece  30 . As before, this specific interface part  30  comprises two parts: a first part  301  forming a sleeve and intended to be glued around the slider of the potentiometer  29 , and a second part  302  forming a hoop and passing around the handle P. The first and second parts  301 ,  302  of the specific interface part  30  are connected to each other in such a way as to be able to swivel one with respect to the other according to one degree of freedom. The potentiometer  29  is fixedly mounted in the surgical instrument  12 . The first part  301  is fixedly mounted on the axis of the potentiometer  29 , which itself is slidable relative to the body of the potentiometer. The second part  302  follows the movements of the activation handle P when it is operated by the operator and then transmits these movements to the first part  301  which transmits them to the slider of the potentiometer  29 . The information is then sent to the computing unit  14 . 
     Each additional sensor  21  is added to the surgical instrument  12  in a manner that is transparent to the operator with respect to the functional surgical instrument. In general, the addition of all the sensors  20   a ,  20   b ,  21  and the electronic card  18  of the electronic system  16  as well as each of the specific interface parts  30  does not significantly alter the mechanical travel or force required to mechanically actuate each primary and/or secondary functional element(s)  26   a  and/or  26   b  of the surgical instrument  12  relative to those of the functional surgical instrument. The physical properties of the surgical instrument  12  (dimensions, shapes, and a centre of mass, etc.) remain, after integration of the electronic system  16 , substantially identical to those of the functional surgical instrument obtained from the factory. The challenge, for each surgical instrument  12 , is thus to add the measurement system of the electronic system  16  in a substantially transparent manner for the operator so as to preserve all the degrees of freedom of the functional surgical instrument. Indeed, the electronic card  18 , each sensor  20   a ,  20   b ,  21  and each specific interface part  30  are integrated into the actual surgical tool  12  in replacement of at least one electronic component of a set of electronic components of the functional surgical instrument. In the example illustrated in  FIGS.  8 A,  8 B , the specific interface part  30  is integrated inside the real surgical tool  12  by attaching (docking) it to an end of the surgical instrument  12 . This attachment is done in such a way that it does not alter the handling parameters of the surgical tool  12 . Thus, in the example shown in  FIGS.  8 A and  8 B , the specific interface piece  30  is attached in continuity with the motor axis of the real surgical tool  12 . The final mass of the real surgical tool  12  is maintained substantially the same as that of the functional surgical tool because the electronic card  18 , each sensor  20   a ,  20   b ,  21  and the specific interface piece  30  are integrated into the real surgical tool  12  in replacement of at least one electronic component of a set of electronic components of the functional surgical instrument, even though they are not integrated at the location where these electronic components were. The specific interface part  30 , the electronic card  18 , the sensors  20   a ,  20   b ,  21  are integrated into the actual surgical tool  12  by attachment (docking) and form a single technical part. Thus, each mass change induced by the addition of a component of the electronic system  16  of the system  10  is compensated by the removal of an electronic component (e.g. a battery) initially present in the functional surgical instrument. 
     The real surgical instrument  12  may be provided with a sound feedback S. This sound feedback, like what exists in the automotive field to help a user to park, allows to give an indication of the available space around the real surgical instrument  12  or even information on the position of an end of the real surgical instrument  12  in the space and allows to help the operator, at the beginning of learning, to perceive the depth of the working space. This sound feedback S gives the distance between the tip of the instrument and the surgical target. This type of feedback allows additional information to be sent to the user without overloading his visual space so that he can concentrate on his task. 
     The actual surgical instrument  12  may furthermore be provided with a spatial location system L, so that the computing unit  14  can determine the position of the real surgical instrument  12  in space relative to a predefined origin at any time. 
     The real surgical instrument  12  may also be provided with a haptic device H so that an interaction with a predefined body can be simulated for the operator. This haptic device H will be described in more detail below. The real surgical instrument  12  may, in addition to the haptic device H, be provided with an overall sensory device, so as to be able to emit, in response to a predefined external signal, a specific sound, light or smell. 
     All the systems added to the real surgical instrument  12 , i.e. the integrated electronic system  16 , the haptic system H, the sonar system S and the spatial localization system L, are transparent to the operator: the real surgical instrument  12  does not lose functionality despite the integration of all these systems and the centre of mass of the real surgical instrument  12  is not changed. 
     Virtual Surgical Instrument 
     As already mentioned, each real surgical instrument  12  of the present invention is intended to be manipulated by an operator and can be activated in at least two distinct operating states. Furthermore, each real surgical instrument  12  has its own geometrical characteristics. In the surgical simulation device  10  of the present invention, to each real surgical instrument  12 , corresponds a virtual surgical instrument  22  (see  FIG.  5   ) having the same geometrical characteristics as those of the corresponding real surgical instrument  12 . This is a virtual twin  22  of the real surgical instrument  12 . Each virtual surgical instrument  22  can be activated to the same operating states as the corresponding real surgical instrument  12 , and the operating state of the virtual instrument  22  aligns, in real time, with the operating state of the corresponding real surgical instrument  12 . 
     In the example shown in  FIG.  5   , the virtual surgical instrument  22  is a cauteriser, a twin of the cauteriser shown in  FIG.  2   . While manipulating the real surgical instrument(s)  12 , the operator views each virtual surgical instrument  22  on the viewing device  24  connected to the computing unit  14 . In addition to viewing each virtual surgical instrument  22  (in the case of  FIG.  6 A , a cauteriser and three trocars t 1 , t 2 , t 3 ), the operator can view an entire virtual operating room  32  (see  FIG.  6 B ) and even a virtual patient  34  on whom he/she is to perform a surgical simulation. The virtual operating theatre  32  and the virtual patient  34  are stored in the computing unit  14  and made visible to the operator by the latter. 
     In the example illustrated in  FIGS.  6 A to  8 B , the surgical simulation concerns a thoracic scoliosis correction. In a classical and known way, this surgery is a minimally invasive surgery and the operator is oriented thanks to an image generated by a camera introduced into the patient&#39;s body by means of one or more trocars. These trocar(s) are also used, in this case, to guide the real surgical tool  12  towards an image of the organ to be operated on (here, the spine) displayed on a screen. In the case of a surgical simulation, the operator acts, by means of the virtual surgical tool  22  on the virtual organ to be operated  36 . In the specific case of the example of minimally invasive surgical simulation illustrated in  FIGS.  6 A to  8 B , the operator sees, on a virtual screen  38 , an image  36 ′ of the virtual organ to be operated  36  (the virtual spine). This virtual screen  38  is part of the virtual operating theatre  32 . As seen in  FIG.  8 A , the operator also sees an image  22 ′ of the virtual surgical tool  22  on the virtual screen  38 . The surgical simulation thus immerses the operator in the real conditions of an operating theatre. 
     This ‘immersion’ produced by virtual reality combined in real time with real instrumentation from real surgical instruments, accelerates the beneficial effects on the training of the auditory, visual and kinaesthetic memory of the trainee (the user). Through this training, the user will, firstly, actively memorise the gesture and actions to be performed for the simulated procedure. And secondly, passively, the interactions between his different senses will create transferable automatisms in a real context. 
     Thus, each of the original sensors  20   a ,  20   b  or additional sensors  21  added to the functional surgical instrument to measure a degree of rotation, a length of stroke, a percentage of closure, a speed, a rate of battery charge, or a pressure allow these same quantities to be reproduced on the virtual surgical instrument  22 . As each sensor is connected to the electronic card  18 , which in turn is connected to the computing unit  14 , the computing unit  14  can therefore, in real time, reproduce the mechanical operation of each real surgical instrument  12  during the simulation. 
     Furthermore, the real surgical instrument  12  may be provided with a haptic device so that an interaction with a predefined body can be simulated for the operator. This predefined body is a virtual body which has a virtual nature and a virtual positioning determined by the computing unit  14 . The operator visualises a virtual equivalent of the predefined body as a virtual anatomical object  40  via the display device  24 . In this case, since it is a minimally invasive surgery, the operator sees an image  40 ′ of each anatomical object  40  surrounding the virtual organ to be operated on  36 . In  FIG.  6 A , ribs can be seen, in  FIGS.  7 A,  7 B , an image of a lung can be seen. 
     Each predefined body therefore simulates a virtual anatomical object  40  in virtual reality. As already mentioned, this virtual anatomical object  40  can be a lung, a liver, a muscle, a bone, etc. The haptic feedback H built into the surgical instrument  12  (complex or mechanical) maximises the realism of the surgical simulation by providing force feedback sensations to the operator. Using a cable system or vibration technology (e.g. an eccentric rotating mass motor (ERM), or a piezoelectric motor, etc.), the palpation or collision of the real surgical instrument  12  (or virtual surgical instrument  22 ) with a virtual anatomical object  40  in the virtual reality can be felt. The operator may also feel the pulling force of a suture, for example. In the case where the real surgical instrument  12  is provided with an overall sensory device, the sound, light and/or smell emitted in response to the external signal further intensifies the immersive experience. 
     Thus, the electronic system  16  integrated into the real surgical instrument  12  allows information on the status of the real surgical instrument  12  to be transmitted in real time to its virtual twin  22 . Like the real surgical instrument  12 , the virtual surgical instrument  22  has at least one virtual functional element  42  (see  FIG.  5   ). This virtual functional element  42  is a twin of the corresponding real functional element  26 . Thus, the operating state of the virtual functional element  42  of the virtual instrument  22  is aligned, in real time, with the operating state of each functional element  26  of the real surgical instrument  12 . To ensure the performance of the immersive experience, the alignment of the functional state of the corresponding real and virtual surgical instruments  12 ,  22  (or their corresponding functional elements  26 ,  42 ) occurs without any apparent delay to the operator. The integrated electronic system  16  is able to follow the evolution of the functional states of the real surgical instrument  12  according to the full functionality of the latter, respecting the ergonomics and geometrical characteristics of the latter, and to be sufficiently miniaturised so as not to add to the weight of the real surgical instrument  12  and so as not to impede the operator during the surgical simulation. 
     It is noted that the surgical simulation device  10  according to the present invention allows an operator to manipulate simultaneously in the physical world and in the virtual world real surgical instruments  12 . Thus, each real surgical instrument  12  used in the operative steps of a surgical procedure is connected in real time to a virtual reality comprising a virtual surgical instrument  22  corresponding to each real surgical instrument  12 . 
     The technology developed by the present invention thus provides a perfect match between the virtual world and the real world, without which the skills acquired in simulation will be insufficient and approximate.