Abstract:
This group of inventions provides means and methods for preventing the damaging portions of surgical tools, such as laparoscopic devices, from adversely contacting tissues and organs that are not in the desired field of surgery. As such, the present disclosure pertains to any form of a warning or positioning device or methods, including those that are facilitated via software that are adapted and arranged for use in tracking portions of surgical instruments during laparoscopic surgery or other medical procedures. Such systems include those that are adapted and arranged to provide a warning to the surgeon or other medical personnel regarding the positional status of an instrument, and those that are adapted and arranged for disabling or attenuating the portions of those instruments that might be dangerous to a patient when a dangerous portion of the instrument is near or outside the desired, or denominated, field of surgery. Data relating to the position and orientation of the instrument and of the position of a safe zone within which the instrument can be kept safely is optionally (preferably) stored throughout a medical procedure for later playback for training purposes or for ensuring that a patient was not injured during a medical procedure.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to systems for reducing accidental injury to patients during surgery and more particularly during laparoscopic surgery. 
       BACKGROUND OF THE INVENTION 
       [0002]    Compared with conventional surgery, laparoscopic surgery is an excellent means for achieving significant reductions in surgery-related morbidity. These reductions are achieved, however, only if the procedure is performed completely and without effective errors. Unfortunately, error-free laparoscopic surgeries are not the rule. Indeed, intra-operative and post-operative complications are all too common with laparoscopic surgery procedures. Because of this, there is a need to improve patient safety during laparoscopic surgery so that the benefits derived from such procedures are achieved while the drawbacks are reduced or eliminated. 
         [0003]    One of the most profound drawbacks of laparoscopic surgery is the occurrence of unintentional or inadvertent injuries to patient tissue structures adjacent to or sometimes, distant from the intended surgical site or field. In the pelvic cavity, for example, bowels, ureters, large organs and blood vessels can be injured either directly from the heat or sharpness of the laparoscopic instruments, or burned indirectly through the conduction of heat through nearby tissues. Typically, such injuries are not appreciated at the time of surgery because the specific injury sites are hidden by blood or other patient tissues. As another disadvantage attendant to such iatrogenic injuries, the response to the unintended injury manifested by the patient is often a delayed one. This delayed response can be traumatic as well as tragic, and can sometimes result in one or more further surgeries, which would otherwise be unnecessary. 
         [0004]    The implications from both a medical perspective as well as a medico-legal perspective are enormous. Obviously, such injuries are negative events and therefore best avoided. The present invention is therefore directed to reducing the occurrence and severity of these negative events. 
       SUMMARY OF THE INVENTION 
       [0005]    In one aspect, the invention defines or denominates a surgical field as a three-dimensional space in which the operative portions of laparoscopic instruments, those portions which are capable of causing harm to the patient or medical personnel, are permitted to function. In some embodiments, the hazardous or dangerous function of the instruments can be automatically attenuated or eliminated outside of this denominated space. The operative portions of a laparoscopic instrument or appliance include those that can potentially cause damage if they contact a patient&#39;s tissues in an unintended manner. Examples of such potentially damaging portions include hot wires, electrically charged wires, blades, scissors and shears, sharp points or surfaces. Thus, the operative portions can include those that are adapted and arranged to do one or more of cut, cauterize, ablate, seal, fuse, skewer or clamp. 
         [0006]    In another significant aspect, in order to track and monitor the relative positions and orientations of the instruments with respect to the protected space, and in order to track a probe used to assist in defining the protected space (ie. a safe zone) the present invention employs one or more of software, optics, high speed digital imaging, such as visible spectrum or infrared (IR) imaging, 2D or 3D ultra sound, MRI and CAT scan images, visible spectrum or infrared (IR) imaging, photography, electromagnetic sensing, radio frequency (RF) sensing as well as one or more sensors to enable the surgeon, operating room and other medical personnel, including remote medical personnel, to be apprised of the precise positional status of the laparoscopic instruments being used. 
         [0007]    Positional status refers to the relative position of the operative and non-operative portions of the various laparoscopic appliances and tools being used with respect to various portions of the patient&#39;s body, or with respect to the denominated surgical field, or with respect to one or more sensors placed inside or outside the patient&#39;s body. 
         [0008]    A positive positional status refers to circumstances where the operative portions of the laparoscopic instruments are within the denominated boundaries of the surgical field. A neutral positional status refers to circumstances where the operative portions of the laparoscopic instruments are in the denominated surgical field but near at least one boundary. A negative positional status refers to circumstances where the operative portions of the laparoscopic instruments are outside of the denominated surgical field, or within a predetermined distance of a sensor. 
         [0009]    Positional status is determined with respect to a three-dimensional surgical field having defined boundaries, or with respect to one or more sensors placed in proximity to vulnerable tissues. In accordance with certain aspects of the invention, those boundaries can be defined in a number of different ways and combinations thereof. For example, in some embodiments, proximity to one or more sensors placed on a vulnerable organ or tissue defines the boundaries of the protected space or denominated field. In other embodiments of the invention, the boundaries of the field can be determined with respect to distance from an object, such as a net used for sequestering the bowel, and the like. Thus, definition of the various boundaries makes it possible to determine the relative positions of various portions of laparoscopic instruments with respect to the denominated surgical field, and with respect to vulnerable tissues and organs, as well as with respect to various medical personnel. 
         [0010]    Thus, in accordance with an embodiment of the invention, the three-dimensional spatial boundaries of a surgical field can be determined, or denominated, in a number of different ways. The present means and methods thus denominate the shape and volume of a three-dimensional space, and also track the position of portions of various instruments with respect to that space. By doing so, the likelihood of inadvertent damage is decreased. This is further enhanced by other aspects of the invention. 
         [0011]    For example, each laparoscopic instrument being used in a particular procedure can have a range of statuses. Each of these statuses can be determined by the instrument&#39;s relative position in the denominated field, for example, by means of distance sensors, magnetic sensors, heat sensors, proximity sensors, 2D or 3D imaging technologies (Ultra-sound, MRI, etc.) and the like. 
         [0012]    Thus, a system of the present invention “knows” where inside the body the operative portions of the laparoscopic instruments are located at all times. The sensors therefore aid the surgeon in staying away from vulnerable tissues and areas within the patient&#39;s body. Moreover, the instruments can be in operative communication, programmed or coded to shut off in the event that a dangerous structure is within the radius of a direct injury or a thermal burn, for instance. In an embodiment the invention reduces morbidity by providing the surgeon and other medical personnel with a “denominated surgical field” or “protected space” within which to perform the indicated procedure while reducing the risk of damage to other organs which, in essence, are provided with a kind of “force field” around them. Thus, in one aspect, the means and methods of the invention function to sequester vulnerable portions of the patient&#39;s body. 
         [0013]    When the borders or limits of the denominated field are breached are approached, the system provides also for warnings to be given, such as a buzz or handle vibration in the laparoscopic tool being used. A system in accordance with an embodiment of the invention can thus be adapted and arranged such that the energized or sharp portions of the appliance are operational only within the boundaries determined by the sensor-enabled laparoscopic field, that is, the denominated field. As an example, in some embodiments, the means and methods of the invention can be adapted and arranged such that the sharp edges of the appliance are automatically withdrawn into one or more sheaths provided as part of the laparoscopic appliance. 
         [0014]    In other embodiments of the invention, the means and methods of the invention can be effected by way of software that controls the various energy inputs to the laparoscopic instruments being used, thus preventing the unwanted cutting, avulsing, cauterizing, ablating, or severing of a patient&#39;s tissues and organs. 
         [0015]    As yet another advantage, the means and methods of the present invention can also be adapted and arranged as teaching tools for providing virtually instantaneous feedback to surgeons and other medical personnel regarding their abilities and techniques in laparoscopic surgery. Various feedback loops and sensitivities of the invention can be adjusted to provide tailored instruction with respect to instructional or experimental surgeries on animals or models. 
         [0016]    In some embodiments, all points, co-ordinates, positions and movements of instruments, body, organs and tissues can be recorded and stored for later playback if necessary. The playback can be provided in any of the following formats: audio, graphs, 2D graphic, and 3D graphic, or in any combination thereof. 
         [0017]    In another aspect, the invention is directed to a surgical system for use on a body of a patient, wherein the system permits the user to determine the positions of a plurality of points on internal body portions of the patient surrounding a surgical field, wherein the points are used by a controller to determine a safe zone in which a functional element on a surgical instrument can be positioned without causing injury to the patient. The positions of the points may be monitored by the controller in real time so that if, after the safe zone is determined initially by the controller, the internal body portions of the patient move, the controller updates the data relating to the safe zone in real time. The system uses a sensor net that is positioned in the surgical field to assist in determining the points that define the safe zone both initially and in real time during a medical procedure. 
         [0018]    In another aspect, the invention is directed to a method of using a surgical system on a body of a patient. The method is used to determine the positions of a plurality of points on internal body portions of the patient surrounding a surgical field, in order to determine a safe zone in which a functional element on a surgical instrument can be positioned without causing injury to the patient. The positions of the points may be updated in real time during a medical procedure so that if the internal body portions of the patient move after the safe zone is determined initially, the data relating to the position of the safe zone can be updated in real time. The method incorporates the use of a sensor net that is positioned in the surgical field to assist in the determining of the points that define the safe zone both initially and in real time during a medical procedure. 
         [0019]    In another aspect, the invention relates to a method of using a surgical system on a body of a patient, comprising:
   (a) providing a probe including an interior portion that is configured to be at least partially inserted into the body of the patient during use, a probe body to which the interior portion of the probe is connected, wherein the probe body is configured to be outside the body of the patient during use, wherein the interior portion of the probe includes a probing portion;   (b) providing a surgical instrument including an interior portion that is configured to be at least partially inserted into the body of the patient during use, an instrument body to which the interior portion of the surgical instrument is connected, wherein the instrument body is configured to be outside the body of the patient during use, wherein the interior portion of the surgical instrument includes a functional element;   (c) providing a laparoscope including an interior portion that is configured to be at least partially inserted into the body of the patient during use, a laparoscope body to which the interior portion of the laparoscope is connected, wherein the laparoscope body is configured to be outside the body of the patient during use, wherein the interior portion of the laparoscope includes an image receiving element, wherein, during use, the image receiving element is positionable in a surgical field in the body of the patient to receive images of the probing portion when the probing portion is in the surgical field and to receive images of the functional element when the functional element is in the surgical field; and,   (d) pre-defining a three-dimensional safe zone in a target region within the body of the patient in which a surgery is to be performed by using the probe to define a denominated surgical field in the target region prior to the surgery being performed.   
 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]      FIG. 1  is a perspective view of a surgical system for use on the body of a patient in accordance with an embodiment of the present invention; 
           [0025]      FIGS. 2   a - 2   d  illustrate the surgical system shown in  FIG. 1  being used to determine a safe zone within the patient in which a surgical instrument can be maneuvered without causing injury to the patient; 
           [0026]      FIG. 2   e  is a perspective view of a surgical instrument being used during a surgical procedure; 
           [0027]      FIG. 3  is a perspective view of an optional net that can be included with the system shown in  FIG. 1 ; 
           [0028]      FIGS. 4   a - 4   d  are examples of markers that can be included on a probe shown in  FIG. 1  to permit tracking of the probe by a camera system; 
           [0029]      FIG. 5  is a magnified perspective view of the net shown in  FIG. 3   
           [0030]      FIGS. 6   a - 6   d  are examples of markers that can be included on a surgical instrument shown in  FIG. 1  to permit tracking of the surgical instrument by a camera system; and 
           [0031]      FIG. 7  is an alternative probe for use with the system shown in  FIG. 1 ; and 
           [0032]      FIGS. 8   a  and  8   b  are a flow diagram of the programming for a controller in the surgical system shown in  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0033]    Reference is made to  FIG. 1  which shows a surgical system  10  for use on a body of a patient in accordance with an embodiment of the invention. The surgical system  10  includes a probe  12 , a laparoscope  14 , a surgical instrument  16  ( FIG. 3 ), a display  17 , netting  18  ( FIG. 3 ) with a plurality of safe zone definition sensors  19  on it, a controller  20  and a tracking system  22 , which in the embodiment shown is a camera system. The surgical system  10  is configured to reduce the incidence of injuries to patients during laparoscopic surgery. 
         [0034]    The system  10  is initially used to determine a safe zone  24  ( FIG. 2   e ) within the patient shown at  26  (only a portion of the patient  26  is shown in  FIG. 1 ) in which the surgical instrument  16  can be maneuvered without causing injury to the patient  26 . The determination of the safe zone  24  involves the probe  12 , the laparoscope  14  in particular. The probe  12  includes a probe body  28  and an interior portion  30  connected to the probe body  28 . The interior portion  30  is configured to be at least partially inserted into the body of the patient  26  through one of a plurality of apertures  32  made in the body of the patient  26 . The particular aperture  32  through which the probe  12  is inserted is shown at  32   a.  The interior portion  30  is therefore made from a material that will not cause harm to the patient, such as, for example, a suitable stainless steel. The probe body  28  is configured to be outside the body of the patient  26  during use. 
         [0035]    The probe  12  further includes a probing portion  34  on the interior portion  30 . The probing portion  34  is a portion of the interior portion  30  and is used to identify the positions of points on the internal body portions shown at  36  ( FIG. 3 ) of the patient  26  that are in the surgical field (ie. that are in the vicinity of the particular site in the patient  26  that requires surgery). The surgical field is shown in  FIG. 3  at  38 . Referring to  FIG. 2   a , the probing portion  34  may be at a tip  40  of the interior portion  30 . The probing portion  34  may have one or more selected properties which may be different from the rest of the interior portion  30  so that other portions of the interior portion  30  cannot be mistaken by the system  10  as being the probing portion  34 . For example, the probing portion  34  may be configured to be magnetic. Alternatively, the probing portion  34  may be configured to be electrically conductive. Alternatively, the probing portion  34  may be heated to a selected temperature. Alternatively, the probing portion  34  may be configured to emit signals at a selected frequency and strength. Alternatively, the probing portion  34  may simply be of the same material as the rest of the interior portion  30 , and may simply be conveniently shaped so as to permit easy pointing at an object (eg. an internal body portion  36 ). 
         [0036]    During use of the probe  12  it is desired for the controller  20  to be able to determine the position of the probing portion  34  at selected times. To this end, a probe marker  42  is provided on the probe body  28 . The probe marker  42  is, during use, viewed by the camera system  22  and is used by the controller  20  to identify the probe  12  (ie. to distinguish the probe  12  over other objects, such as the instrument  16 ). Additionally or alternatively, the probe marker  42  is configured to provide sufficient information to the controller  20  for the controller  20  to be able to determine the position and orientation of the probe marker  34 . By determining the position and orientation of the probe marker  34 , the controller  20  can determine the position and orientation of the probe  12  itself and therefore can determine the position of the probing portion  34 . Determining the position of the probing portion  34  is used by the controller  12  in determining where the internal body portions  36  of the patient  26  are, which is then used by the controller  20  to determine the safe zone  24 . 
         [0037]    As shown in  FIG. 6   a  the probe marker  42  may, for example, be made up of a plurality of LEDs  44  on the probe  12 . Some aspect of the LEDs  44  is unique so as to facilitate detection of the probe marker  42  in the images sent by the camera system  22  to the controller  20  and optionally to distinguish the probe marker  42  from an analogous marker on the surgical instrument  16 . For example, the arrangement of the LEDs  44  on the probe body  28  may be distinguishable by the controller  20  to detect the probe marker  42  and optionally to identify it as the probe marker  42  as opposed to the aforementioned marker on the surgical instrument. Alternatively or additionally, the LEDs  44  may be configured to emit light at a particular wavelength or combination of wavelengths of light. 
         [0038]    The LEDs  44  may be configured to emit light at a non-visible wavelength (eg. infrared) so as to not distract the user of the probe  12  (eg. the surgeon) during use. 
         [0039]    As an alternative to LEDs, the probe marker  42  may be made up of any suitable means for identifying the probe  12  and for identifying the position and orientation of the probe  12 . For example, the probe marker  42  may include one or more symbols  47   a  (eg. polygons) on a suitable background  47   b  as shown in  FIG. 6   b . The colour of the symbols  47   a  and the colour of the background  47   b  may be selected to be of sufficient contrast to facilitate locating the symbols on the background, and may be selected to be sufficiently unique so as to permit the controller  20  to detect the probe marker  42  in the images provided by the camera system  22 . Alternatively, as shown in  FIG. 6   c , a combination of LEDs  44  and symbols  47   a  and a background  47   b  may be provided. As shown in  FIG. 4   d , the probe marker  42  may be removable from the probe body  28 . For example, the marker  42  may be provided on a sleeve. 
         [0040]    The netting  18  may have several purposes. For example, the netting  18  may be positionable to restrain at least some of the internal body portions  36  in the surgical field  38  from obstructing the surgical instrument  16  when the surgical instrument  16  is being used in the surgical field  38 . Alternatively, the netting  18  may simply be provided to conform to the shape of at least some of the internal body portions  36  in the surgical field  38 . The netting  18  may be provided with any suitable means for restraining the internal body portions  36 . For example, the netting  18  may be provided with a plurality of hold down members  46  which extend out of the body of the patient  26  and which may be attached to suitable attachment points on a support frame (not shown). Alternatively, the netting  18  may be provided with one or more hold down members that connect to other points within the body of the patient  26 . Alternatively, the netting  18  may be provided with a grippy, elastic peripheral edge permitting the netting  18  to be mounted over internal body portions  36  and to hold on to the body portions  36  themselves. The netting  18  may be made up of one or more individual nets each of which is affixed to internal body portions  36  around the surgical field  38 . 
         [0041]    The plurality of safe zone definition sensors  19  on the netting  18  are configured to communicate with the controller  20  and to cooperate with the probe  12  to establish the positions of points on at least some internal body portions  36  in the surgical field  38  to assist in the determination of the safe zone  24  by the controller  20 . The safe zone definition sensors  19  may be any suitable type of sensors, such as, for example, electromagnetic (EM) sensors, magnetic sensors, heat sensors, radio frequency (RF) sensors, proximity sensors, GPS, Hall Effect sensors and any other suitable type of sensor. Each safe zone definition sensor  19  is configured to detect when the probing portion  34  is at a selected proximity to it. 
         [0042]    In an exemplary embodiment, each safe zone definition sensor  19  is configured to detect when it is contacted by the probing portion  34 . For example, the sensor  19  may be configured to detect self-movement, which would take place when contacted by the probing portion  34 . Alternatively or additionally the sensor  19  may determine contact by the probing portion  34  by some other means. For example, contact with the probing portion  34  may close an electrical circuit through the sensor  19 , which could be used to send a signal to the controller  20  that contact is made with the probe  12 . 
         [0043]    Each sensor  19  may include an accelerometer that is capable of detecting self-movement in three dimensions. When detecting self-movement, the sensor  19  is configured to communicate the amount of self-movement to the controller  20  so that the controller  20  can update the position of the sensor  19  in real time. Because the position of the sensors  19  indicates the position of the internal body portions  36  of the patient  26 , the controller  20  can thus determine if the internal body portions  36  move during surgery, and can use this information to continuously determine a new safe zone  24  ( FIG. 2   e ) in real time during surgery. 
         [0044]    The sensors  19  may communicate with the controller  20  via any suitable means. For example, an electrical conduit  48  ( FIG. 3 ) may extend from the sensors  19  out of the body of the patient  26  to the controller  20 . 
         [0045]    The laparoscope  14  includes a laparoscope body  50  and an interior portion  52  connected to the laparoscope body  50 . The interior portion  52  is configured to be at least partially inserted into the body of the patient  26  through one of the apertures  32 . The particular aperture  32  through which the probe  12  is inserted is shown at  32   b.  The interior portion  52  is therefore made from a material that will not cause harm to the patient, such as, for example, a suitable stainless steel. The laparoscope body  50  is configured to be outside the body of the patient  26  during use. 
         [0046]    The interior portion  52  includes an image receiving element  54 . During use, the image receiving element  54  is positionable in the surgical field  38  in the body of the patient  26  to receive images of the probing portion  34  when the image receiving element  54  is in the surgical field  38 . The image receiving element  54  may be a lens, for example. The laparoscope  14  is configured by any suitable means to transmit received images to the display  17 . For example, the laparoscope  14  may include an image sensor (not shown), which may be, for example, a CCD sensor or a CMOS sensor, that is positioned to receive images from the image receiving element  54 . The laparoscope  14  is configured to transmit the images of the probing portion  34  to the display  17  (optionally via a controller such as the controller  20 ). 
         [0047]    The surgical instrument  16  includes an instrument body  90  and an interior portion  92  connected to the instrument body  90 . The interior portion  92  is configured to be at least partially inserted into the body of the patient  26  during use. The instrument body is configured to be outside the body of the patient during use. The interior portion  92  includes a functional element  94 , which is an element that is configured to perform a particular function on the patient. For example, the functional element  94  may be a cutting blade, a scissors mechanism or for example a heating element to cauterize. As will be understood, the functional element  94  may cause unintended injury to the patient  26  if it is accidentally brought into contact with the internal body portions  36  of the patient  26  surrounding the surgical field  38 . 
         [0048]    During use of the surgical instrument  16  it is desired for the controller  20  to be able to determine the position of the functional element  94  substantially continuously. To this end, an instrument marker  96  is provided on the instrument body  90 . The instrument marker  96  is, during use, viewed by the camera system  22  and may be used by the controller  20  to identify the surgical instrument  16  (ie. to distinguish the surgical instrument  16  over other objects, such as the probe  12 ). Additionally or alternatively, the instrument marker  96  is configured to provide sufficient information to the controller  20  for the controller  20  to be able to determine the position and orientation of the instrument  16 . By determining the position and orientation of the instrument marker  96 , the controller  20  can determine the position and orientation of the surgical instrument  16  itself and therefore can determine the position of the functional element  94 . Determining the position of the functional element  94  is used by the controller  12  in determining whether the functional element  94  is within the safe zone  24 . 
         [0049]    Some examples of instrument markers  96  are shown in  FIGS. 4   a ,  4   b ,  4   c  and  4   d . The instrument marker  96  may includes LEDs  44  ( FIG. 4   a ), one or more symbols  47   a  (eg. polygons) on a suitable background  47   b  ( FIG. 4   b ), or a combination of the two ( FIG. 4   c ). The instrument marker  96  may be removable from the instrument body  90  as shown in  FIG. 4   d . For example it may be provided on a sleeve. 
         [0050]    The camera system  22  includes at least one camera  56  and preferably includes a plurality of cameras  56  mounted around the surgical theatre. The cameras  56  are positioned at selected positions to reduce the likelihood of obstruction of their view of the probe marker  42  and the instrument marker  96 . The cameras  56  receive images of the probe marker  42  and transmit the images to the controller  20 . The controller  20  is programmed to locate the probe marker  42  in the images and to determine by any suitable means, the position and orientation of the probe  12  and therefore the position of the probing portion  34 . This may be achieved by comparing the images from two or more cameras  56  and using triangulation. Alternatively, a stereoscopic camera  56  may be used, so as to provide three-dimensional position information through images sent to the controller  20  without using multiple cameras. Alternatively, a single non-stereoscopic camera  56  may be used which sends a non-stereoscopic image to the controller  20 . The controller  20  can determine easily the position of the marker  42  in the two dimensional plane of the image easily and the depth of the probe marker  42  (ie. its distance from the camera along a third dimensional axis perpendicular to the plane of the image) may be determined based on the apparent size of the marker  42  in the image. 
         [0051]    Providing two or more cameras  56  may be advantageous to reduce the likelihood of the surgeon&#39;s hands or body from preventing the camera system  22  from obtaining an unobstructed view of the probe marker  42 . In an embodiment where at least two cameras  56  are required to have an unobstructed view of the marker  42 , the camera system  22  preferably includes 3 or more cameras  56 . 
         [0052]    Instead of incorporating cameras, the tracking system  22  could alternatively incorporate other types of tracking system sensor that is configured to sense the position of the probe marker and the instrument marker. For example, the tracking system could incorporate one or more of the following exemplary techniques to sense the position of the instrument  16  and of the probe  12 : 2D or 3D ultra sound, MRI and CAT scan images, electromagnetic sensing, radio frequency (RF) sensing. Regardless of the technique used, and the technology used, whatever is on the probe and on the instrument that is detected by the tracking system may be considered a probe marker and an instrument marker respectively. 
         [0053]    The operation of determining the safe zone  24  is as follows, with reference to  FIGS. 1-6  and with reference to the flow diagram  200  shown in  FIGS. 8   a  and  8   b . Initially, a probe, a surgical instrument, a laparoscope, a tracking system, and netting with the sensors  19  therein are provided in steps  202 ,  204 ,  206 ,  208  and  210  ( FIG. 8   a ). Then a plurality of points  58  on internal body portions  36  that surround the surgical field  38  are determined. To do this, the user creates the apertures  32 . The user inserts the netting  18  with the sensors  19  thereon into the surgical field  38  through one of the apertures  32  and affixes the netting  18  as desired. The user inserts the laparoscope  14  into the surgical field  38 . The user inserts the probe  12  into the surgical field  38 . The camera system  22  receives images of the probe marker  42  and transmits the images to the controller  20  (the images thus constitute probe marker input). The user can see the probing portion  34  of the probe  12  on the display  17  via the transmission of images from the laparoscope  14  to the display  17 . Using the images from the laparoscope  14  the user guides the probe  12  so that the probing portion  34  contacts a first of the safe zone identification sensors shown at  19   a.  When the first sensor  19   a  senses contact with the probing portion  34 , the first sensor  19   a  indicates the occurrence of the contact to the controller  20  (step  212 ). In this particular example, the first point  58   a  on the internal body portions  36  is substantially immediately adjacent the probing portion  34 , since they are separated only by the sensor  19   a,  which may be thin. When the controller  20  receives the indication from the first sensor  19   a  that contact was made, the controller  20  determines the position of the probing portion  34  of the probe  12  (step  214 ) based on the one or more images that were received from the camera system  22  at the time that the indication of contact from the sensor  19   a  was sent. The indication of the contact with the first sensor  19   a,  in combination with the one or more images from the camera system  22  may be considered input indicating the position of a first point  58   a  on the internal body portion  36 . The controller  20  may use any suitable method for determining the position of the probing portion  34 . The controller  20  uses the one or more images to determine the position and orientation of the probe marker  42 , and thus the probe  12 . The method used for this determination depends on whether the camera system  22  provides a single non-stereoscopic image, a plurality of non-stereoscopic images, or one or more stereoscopic images. It will be understood by one skilled in the art however, that many suitable algorithms exist for the determination of the position and orientation of an object using one or more images. 
         [0054]    Once the controller  20  has determined the position and orientation of the probe  12 , the controller  20  can then determine the position of the probing portion  34  based on the distance between a selected portion of the probe marker  42  and the probing portion  34  (which is a known value that is stored in the controller&#39;s memory). Using the position of the probing portion  34 , the controller  20  can determine the position of the safe zone definition sensor  19   a,  and thus the position of point  58   a  (step  216 ). In this example, because the sensor  19   a  is substantially immediately adjacent the probing portion  34  and is thin, the determined position of the point  58   a  on the internal body portions  36  may be considered to be the same as the position of the probing portion  34 . Once the position of the point  58   a  on the internal body portions  36  is determined, the controller  20  records it for use in determining the safe zone  24 . After contacting the first sensor  19   a,  the user guides the probe  12  using the laparoscope  14  and display  17  so that the probing portion  34  contacts a second sensor  19   b  for the purpose of having the controller  20  determine the position of a second point  58   b  on the internal body portions  36 . The user continues to go from sensor  19  to sensor  19  until all the sensors  19  have been contacted. In the flow diagram  200  this is shown by the controller  20  checking at step  218  if indications have been received from all the sensors  19  and sending program control back to prior to step  212  if the answer to the check step  218  is ‘no’. 
         [0055]    While one particular sensor  19  was referred to in this example as the first sensor  19   a,  it will be understood that any of the sensors  19  could have been referred to as the first sensor  19   a,  and any of the sensors  19  could have been referred to as sensor  19   b,  and so on. 
         [0056]    Once the positions of the points  58  corresponding to the positions of the sensors  19  have been identified, (ie. the answer to check step  218  is ‘yes’) the controller  20  determines the safe zone  24  based on the points  58  (step  220 ). The points  58  may thus be referred to as safe zone defining points. The safe zone  24  may be determined by generating a plurality of virtual surfaces shown at  60  in  FIG. 2   d  between the points  58 . The controller  20  may generate the virtual surfaces  60  between groups of points  58 , as shown in  FIG. 2   d . The surfaces  60  may, for example, be quadrilateral surfaces between groups of 4 points  58 , or may be triangular surfaces between groups of 3 points  58 , or may be surfaces having some other number of sides between correspondingly sized groups of points  58 . The virtual surfaces  60  define the periphery of the safe zone  24 , which can be considered to be a virtual conduit through which the functional element  94  of the instrument  16  can pass without causing injury to the patient  26 . 
         [0057]    In addition to determining points  58  based on the positions of the sensors  19 , the probe  12  may be used to determine some points  58  that are not based on the sensors  19 . For example, the probe  12  may be positioned with the aid of the laparoscope  14  so that the probing portion  34  contacts the tip of a bone. When in contact with the bone, the user may indicate to the controller  20  to determine the position of the probing portion  34 . For example, the probe  12  may include a button  103  as shown in  FIG. 7 , which the user can press to indicate to the controller  20  to determine the position of the probing portion  34 . 
         [0058]    Once the points  58  have been determined, they may be stored in a database as shown at step  221 . After the positions of the points  58  have been determined, the probe  12  may be removed from the patient  26 . 
         [0059]    The surgical instrument  16  is then used on the patient to carry out some task, such as cutting, cauterizing or some other suitable task. During use of the surgical instrument  16 , it is possible that the internal organs of the patient may move. If the internal body portions  36  move during surgery it is important that the determined safe zone  24  be updated so as to continue to be useful in preventing inadvertent injury to the patient  26 . In order to provide this capability, the sensor  19  associated with each point  58  is capable of sensing self-movement, and indicates to the controller  20  the amount of movement it has incurred in three dimensions. By having the sensors  19  indicate their movement to the controller  20 , the controller  20  can update the positions of the associated safe zone defining points  58  relating to the moved sensors  19  and can update the surfaces  60  that define the safe zone  24 . In this way, the safe zone  24  can be updated continuously so that the functional element  94  is prevented from injuring the patient  26  even if the internal body portions  36  of the patient  26  move after the safe zone  24  has been initially determined. This is represented as step  222  in  FIG. 8   b . At step  223 , the updated points are also stored in the database. 
         [0060]    Any points  58  that were determined without the use of associated sensors  19  cannot be updated as described above, since there are no associated sensors  19  to sense movement of the point  58 . Instead, these points  58  may be considered by the controller  20  to be fixed (ie. non-moving during the course of the medical procedure). Preferably any such points are points that are not expected to move during the medical procedure, such as points on certain bones. 
         [0061]    During use of the surgical instrument  16 , the camera system  22  receives images of the instrument marker  96  and sends the images (which may be referred to as instrument marker input) to the controller  20  (step  224 ). The controller  20  processes the input using a similar algorithm to that used for determining the position of the probing portion  34 , to determine the position of the functional element  94  (step  226 ). This information is used to determine whether the functional element  94  is within the safe zone  24  (step  228 ). If the functional element  94  is outside the safe zone  24  (ie. the answer to check step  228  is ‘no’), the controller  20  is programmed to carry out at least one action selected from the group of actions consisting of: notifying the user of the surgical instrument  16  that the functional element  94  is outside the safe zone  24 ; and disabling the functional element  94  (step  230 ). 
         [0062]    Disabling the functional element  94  may be carried out in a number of ways depending on what makes up the functional element  94 . For example, if the functional element  94  is a heating element, power may be cut to it. Alternatively, if the functional element  94  includes a sharp edge (eg. a cutting blade), the instrument  16  may include a sheath, and may be configured to automatically cover the functional element  94  with the sheath. 
         [0063]    The controller  20  may notify the user in any suitable way that the functional element  94  is outside the safe zone  24 . For example, the controller  20  may be configured to generate a selected sound via a speaker, and/or may be configured to generate a selected image on the display  17 . 
         [0064]    If the functional element  94  is within the safe zone  24  (ie. the answer at check step  228  is ‘yes’), the controller  20  sends program control to step  232 , wherein it checks if the medical procedure has been completed. This may be indicated by the user pressing a power button or some other control to let the system know to stop. If the procedure is over (ie. the answer to check step  232  is ‘yes’), then the program (and thus the method) ends. If the answer to the check step  232  is ‘no’, then the controller  20  continues to check and update the safe zone  24  as mentioned above at step  222  and to continue to receive instrument marker input at step  224 . 
         [0065]    The controller  20  may be programmed to divide the safe zone  24  ( FIG. 2   e ) into two or more sub-zones. For example, the safe zone  24  may be divided into a safest zone  98  and a danger zone  100 . The safest zone  98  is a central portion of the safe zone  24 . If the functional element  94  is kept within the safest zone  98  there is a reduced risk that the user will accidentally move the instrument  16  in such a way as to cause the functional element  94  to contact and cause injury to an internal body portion  36 . The danger zone  100  is a peripheral portion of the safe zone  24 . In other words it is the portion of the safe zone  24  immediately inwardly adjacent to the virtual surfaces  60  that define the periphery of the safe zone  24 . With the safe zone  24  thus divided into multiple sub-zones, the controller  20  may be configured to notify the user via sound and/or images on the display  17  whether the functional element  94  is in a relatively safer part of the safe zone  24  (eg. the safest zone  98 ) or is in a relatively less safe part of the safe zone  24  (eg. the danger zone  100 ). For example, a green bar may be displayed on the display  17  when the functional element  94  is within the safest zone  98 , a yellow bar may be displayed on the display  17  when the functional element  94  is within the danger zone  100 , and a red bar may be displayed when the functional element  94  is outside of the safe zone  24 . In another embodiment, the controller  20  may be programmed to give the user a continuously changing indication of the distance of the functional element  94  from the periphery of the safe zone  24 , via sound and/or images. For example, the controller  20  may be programmed to emit sound elements (eg. beeps) at a selected frequency of emissions (eg. 2 beeps per second) if the functional element  94  is relatively far from the periphery of the safe zone  24 . If the functional element  94  moves closer to the periphery of the safe zone  24 , the frequency of the beeps may gradually increase (eg. up to, for example, 5 beeps per second). If the element  94  leaves the safe zone  24 , the sound may become continuous. 
         [0066]    After the surgical procedure is completed, the instrument  16 , the laparoscope  14  and the netting  18  may be removed from the patient  26 . 
         [0067]    It will be understood that, while it is convenient to have the sensors  19  on the netting  18 , it is alternatively possible for at least some of the sensors  19  to be provided without netting  18 . These sensors  19  could be inserted individually through an aperture  32  an applied directly to an internal body portion  36  using, for example, a mild adhesive. It will also be understood that the netting  18  may be provided without sensors  19  on it. The netting  18  in such an instance can still be useful to assist in restraining internal body portions from obstructing the surgical instrument  16 . 
         [0068]    The controller  20  may be configured to record the movements of the surgical instrument and the data relating to the safe zone  24  (ie. the positions of the safe zone defining points  58  throughout the medical procedure). The recording may be made a printed recording, or in a more preferred embodiment, the recording may be made as data written to a database stored on a computer readable medium, such as a flash memory so that the surgical procedure can be played back and reviewed. Instead of a database, the data could be stored in some other computer readable format such as a data file containing a simple list. The capability to play back and review the movements of the instrument and the safe zone in a medical procedure can be useful to for a variety of purposes. For example, the procedure can be reviewed and explained to students in order to train them in the safe carrying out of such a procedure. Also, in the event that there is a complication during the recovery of the patient, the procedure can be reviewed to ensure that there was no injury that occurred that is the source of the complication. 
         [0069]    The recording of the data and the movements of the instrument can be provided in any suitable format, such as, for example, audio, graphs, 2D graphic, and 3D graphic, or some combination thereof. 
         [0070]    Throughout this disclosure, the components, such as the cameras, the laparoscope, the safe zone definition sensors and the probe have been shown and described as communicating with the controller via suitable electrical conduits such as wires. It will be understood that it is alternatively possible for any of these components to communicate with the controller via wireless means, such as a Bluetooth® connection. 
         [0071]    It has been disclosed that the instrument marker  96  and the probe marker  42  be used to identify the instrument  16  and the probe  12  to the controller  20 , (ie. to distinguish each from each other and from any other components sensed by the controller  20 ). However, an element that is separate from the marker  42  or  96  could alternatively be provided on the instrument  16  and the probe  12  respectively to identify each to the controller  20 . For example, a unique RFID tag can be provided on each to identify each to the controller  20 . 
         [0072]    While the above description constitutes a plurality of embodiments of the present invention, it will be appreciated that the present invention is susceptible to further modification and change without departing from the fair meaning of the accompanying claims.