Laparoscope positioning apparatus

Abstract

The apparatus 100 comprises a main arm having a first end with a mounting structure 112 for attaching the main arm to a support, and an opposite second end having a carrier 140 for holding a laparosco

Description

FIELD This disclosure relates to systems for positioning and / or guiding surgical instruments, and in particular to a laparoscope positioning apparatus. BACKGROUND Laparoscopy is a surgical procedure used to examine the organs in the abdomen. It typically involves a thin lighted tube called a laparoscope, which includes a camera at its distal end. Operating teams for laparoscopic procedures must consist of the surgeon, an assistant, and a scrub nurse. During laparoscopy, a patient is positioned supine, the surgeon stands at the patient’s side, the assistant stands next to the surgeon, and the scrub nurse and trolleys with equipment are positioned on the opposite side of the patient. Typically, a screen displaying a captured camera image is positioned in front of the surgeon when the surgeon stands upright. Typically, three laparoscopic ports are inserted into the patient’s abdomen to perform a laparoscopic surgery, such as appendectomy. The ports allow for two instruments to be placed into the abdomen, which are controlled by the surgeon, and for one laparoscope to be inserted into the abdomen, which is controlled by the assistant. During the procedure, the assistant holds and positions the laparoscope such that the camera views the instruments while the surgeon uses them to perform the surgery. Therefore, the primary, and usually only, task of the assistant in a laparoscopic procedure is positioning the laparoscope. There have been attempts to minimise the assistant’s involvement in the procedure and to give the surgeon control over it. Such attempts typically involve a linkage system to control the orientation of the camera or the distance the camera is from an area of interest. These devices are used to manipulate the camera such that it moves in up to four degrees of freedom, namely pitch, yaw, roll, and translation. The surgeon would typically have control over the translation of the camera to move it closer to or further away from the area of interest to effectively zoom in or out. In that scenario, the assistant would control the pitch, yaw, and roll. A linkage system may provide the surgeon with more control but is bulky and has variable stability in that the further the camera is from the support or base of the laparoscope, the greater the moment about the support. However, providing the surgeon some control still does not eliminate the requirement for an assistant as the surgeon’s hands are occupied by the instruments. The assistant must manually adjust the laparoscope in at least one of the degrees of freedom such that an image displayed on a screen shows the instruments and the area of interest from the perspective of the surgeon. The preceding discussion of the background is intended only to facilitate an understanding of the present disclosure. It should be appreciated that the discussion is not an acknowledgment or admission that any of the material referred to was part of the common general knowledge in the art as at the priority date of the application. SUMMARY In accordance with an aspect of the disclosure there is provided a laparoscope positioning apparatus comprising: a main arm having a first end with a mounting structure for attaching the main arm to a support, and an opposite second end having a carrier for holding a laparoscope; wherein the main arm includes a number of movable arm segments connected together by which a position of the laparoscope can be changed; and wherein movement of the arm segments is controlled by a control system which receives video data from the laparoscope, identifies at least one surgical instrument visible within a field of view of the laparoscope, and changes the position of the laparoscope based on the relative position of the at least one surgical instrument in the field of view. The control system may identify two surgical instruments visible within the field of view of the laparoscope. The control system may change the position of the laparoscope so that a focal area is centred between the two surgical instruments. The control system may change the position of the laparoscope by moving it closer to or further away from the two surgical instruments so that both surgical instruments may remain within the field of view. The control system may change the position of the laparoscope so that each surgical instrument may remain within a band or zone offset from a centre of the field of view. The arm segments may include a first arm segment which may extend from the mounting structure to a swivel joint, a second curved arm segment which may be movable in translation relative to the swivel joint, and a third arm segment which may be connected to the second arm segment and may have the laparoscope carrier movable in translation relative to the third arm segment. The carrier may rotate the laparoscope about its own axis. The position of the laparoscope may be movable in four degrees of freedom. The four degrees of freedom may be pitch, yaw, roll and forwards-backwards. Pitch may be movable by means of the translation of the second arm segment relative to the swivel joint. Yaw may be movable by means of the movement of the swivel joint. Roll may be movable by means of the rotation of the laparoscope about its own axis. Forward-backwards may be movable by means of the translation of the laparoscope carrier. Roll may be controlled manually by means of a first foot controller. In addition, image rotation may be accomplished by means of the control system controlling a display orientation of the video data and causing such orientation to progressively change so as to rotate the display orientation thereby rotating the field of view of the laparoscope. Any of the degrees of freedom may be controlled automatically by the control system when the control system is in an active state. The control system may be switched between the active state and an inactive state by means of a second foot controller. The at least one surgical instrument may include a marker by which the control system may identify the surgical instrument. In accordance with a further aspect of the invention there is provided a method of controlling a position of a laparoscope during laparoscopic surgery, comprising, by means of a control system: receiving video data from a laparoscope held by a laparoscope positioning apparatus, the laparoscope positioning apparatus including a number of movable arm segments connected together by which a position of the laparoscope can be changed; analysing the video data to identify at least one surgical instrument visible within a field of view of the laparoscope; and controlling movement of the arm segments so as to change the position of the laparoscope based on the relative position of the at least one surgical instrument in the field of view. The method may include identifying a marker on the at least one surgical instrument. The method may include controlling the movement of the arm segments based on the relative position of the marker in the field of view. The video data may be analysed to identify two surgical instruments visible within the field of view of the laparoscope. The method may include controlling the movement of the arm segments to position the laparoscope so that a focal area may be centred between the two surgical instruments. The method may include changing the position of the laparoscope by moving it closer to or further away from the two surgical instruments so that both surgical instruments may remain within the field of view. The position of the laparoscope may be changed so that each surgical instrument may remain within a band or zone offset from a centre of the field of view. The method may include moving one of the arm segments to change the position of the laparoscope within a degree of freedom associated with that arm segment. The method may include changing a yaw of the laparoscope by means of movement of a swivel joint and a first arm segment, the first arm segment extending from a mounting structure to the swivel joint. The method may include changing a pitch of the laparoscope by translating a second arm segment, connected to the swivel joint, relative to the swivel joint. The method may include moving the laparoscope forwards-backwards by translating a carrier on a third arm segment connected to the second arm segment, the carrier holding the laparoscope. The method may include and rotating the laparoscope about its own axis with the carrier. The method may include manually controlling the rotation of the laparoscope about its own axis by means of a first foot controller. In addition, image rotation may be accomplished by means of the control system controlling a display orientation of the video data and causing such orientation to progressively change so as to rotate the display orientation thereby rotating the field of view of the laparoscope, for example so as to compensate for the rotation of the laparoscope and reorient the display to a correct point of view. The method may include automatically controlling any one or more of the degrees of freedom when the control system may be in an active state. The method may include switching the control system between the active state and an inactive state by means of a second foot controller. Embodiments of the technology will now be described, by way of example only, with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS In the drawings: Figure 1 is a side view of an exemplary embodiment of a laparoscope positioning apparatus, according to aspects of the invention, holding a laparoscope and connected to a support; Figure 2 is a three-dimensional view of part of a main arm of the laparoscope positioning apparatus of Figure 1 holding a laparoscope; Figure 3 is a three-dimensional view of a second curved arm segment of the laparoscope positioning apparatus of Figure 1; Figure 4 is a side view of the second curved arm segment of Figure 3; Figure 5 is an exemplary side view of the main arm of Figure 2 with the laparoscope positioned substantially horizontally; Figure 6 is an exemplary side view of the main arm of Figure 2 positioned with the laparoscope pointing generally downwards; Figure 7 is a three-dimensional view of a third arm segment of the laparoscope positioning apparatus of Figure 1; Figure 8 is another side view of the laparoscope positioning apparatus of Figure 1 connected to a hand controller and a foot controller; Figure 9 is an exemplary perspective view demonstrating the degree of freedom each arm segment of the main arm of the laparoscope positioning apparatus of Figure 1 is responsible for; Figures 10 and 11 are side and three-dimensional views of an exemplary laparoscope the laparoscope positioning apparatus of Figure 1 may hold; Figure 12 is a three-dimensional view of the laparoscope positioning apparatus of Figure 1 in use with a test abdomen; Figure 13 is a side view of the laparoscope positioning apparatus of Figure 1 in use by a surgeon holding surgical instruments; Figures 14 to 20 are exemplary fields of view of a laparoscope in use with the laparoscope positioning apparatus of Figure 1; and Figure 21 is a block diagram showing steps of a method of controlling a laparoscope positioning apparatus according to aspects of the invention. DETAILED DESCRIPTION WITH REFERENCE TO THE DRAWINGS Embodiments of the invention provide for a laparoscope position apparatus configured to receive and move a laparoscope. The apparatus may move the laparoscope such that a camera of the laparoscope may record surgical tools used by a surgeon during laparoscopy. The video recording may provide the surgeon with a live video feed of the surgical tools. The apparatus, or at least a segment thereof, is controlled by a control system which receives video data from the laparoscope, identifies at least one surgical instrument or tool visible within the field of view of the camera, and changes the position of the laparoscope based on the relative position of the at least one surgical instrument in the field of view. The laparoscope positioning apparatus includes a main arm having a first end with a mounting structure for attaching to a support. An opposite second end of the main arm includes a carrier configured to hold the laparoscope. The support may be any support acting as a stable structure providing stability to the apparatus. The support may attach to an operating table or be securely fastened to the floor. It should be appreciated that the support may only provide stability to the main arm for smooth and stable movement of the laparoscope during operation. In a preferred embodiment, the support may not be part of the laparoscope positioning apparatus. However, there may be another embodiment where the laparoscope positioning apparatus includes the support. The main arm includes a number of arm segments connected together by which the position of the laparoscope can be changed or manipulated. Each arm segment may be responsible for movement of the laparoscope within a degree of freedom. The arm segments are connected to the support by the mounting structure. The main arm may include a first arm segment extending from the mounting structure to a swivel joint. The swivel joint may connect a second arm segment to the first arm segment. The second arm segment may be curved and may be movable relative to the swivel joint. More specifically, the second curved arm segment may be slidable relative to the swivel joint. The movement of the second arm segment relative to the swivel joint, or first arm segment, may manipulate the pitch of the laparoscope. The curvature of the second curved arm segment may define a pitch path the laparoscope may follow when moved by the apparatus. The main arm may include a third arm segment having the laparoscope carrier. The third arm segment may be connected to the second arm segment. The third arm segment may be responsible for adjusting the translation of the laparoscope such that it moves linearly along its axis. At least part of the third arm segment may be configured to move linearly relative to its connection with the second arm segment. More specifically, the third arm segment may include a translation mechanism moving the carrier along a laparoscope axis and relative to a portion of the third arm segment. The linear translation of the laparoscope via the third arm segment may be responsible for a zoom function of the laparoscope’s video feed. For example, translating the laparoscope along its axis towards a focus point may cause the area around the focus point to enlarge on the camera view, resulting in a zoomed-in camera view. Similarly, translating the laparoscope away from the focus point may cause the area around the focus point to shrink on the camera view, resulting in a zoomed-out camera view. The third arm segment may also be responsible for the roll movement of the laparoscope about its axis. More specifically, the carrier may be responsible for the roll movement of the laparoscope. Furthermore, the control system may be able to identify the at least one surgical tool in the field of view of the laparoscope and may control each of the arm segments to adjust a specific degree of freedom of the laparoscope. For instance, when the at least one surgical tool is moved towards a surgeon along a horizontal plane, the control system may instruct and adjust the second curved arm segment to adjust the pitch or the yaw of the laparoscope such that the surgical tool remains in the field of view. Similarly, moving the tool towards or away from the laparoscope may cause the control system to translate the laparoscope along its axis. It should be appreciated that the control system may control the movement of each arm segment individually and may control them all simultaneously. Moving only one arm segment may move the laparoscope within a single degree of freedom. The simultaneous movement of multiple arm segments may move the laparoscope in multiple degrees of freedom simultaneously. The control system may further be configured to receive and process instructions from a user to control the movement of the main arm and the laparoscope. Laparoscopes may have a lens with an optical axis that is offset from the longitudinal axis of the laparoscope itself, e.g. as illustrated in Figure 5. Physical rotation of the laparoscope is used to change the object of interest being viewed, but results in objects in the video feed rotating. To compensate forthat, the control system may enable digital rotation to reorient the on-screen image to a correct point of view of the clinician. This digital rotation may therefore be considered an additional (virtual) degree of freedom. It should be appreciated that the digital adjustment of the orientation of the video may be manually controlled, for example by a foot controller. The control system may further be toggled or switched between an active and inactive state by a user. In the active state, the control system may automatically adjust the movement, i.e. pitch, yaw, roll, and translation, of the apparatus, and thus the laparoscope, upon moving the surgical instrument. In the inactive state, the control system may not adjust the movement of the laparoscope in at least one degree of freedom upon movement of the surgical instrument. More specifically, in the inactive state, the control system may keep the laparoscope still and stationary upon movement of the surgical instrument. Figures 1 to 13 illustrate an exemplary embodiment of a laparoscope positioning apparatus (100). Figure 1 shows the laparoscope positioning apparatus (100) attached to a support and holding a laparoscope (102). The apparatus (100) includes a main arm having a mounting structure (112) at a first end of the main arm for attaching the main arm to the support, which may be an operating table (not shown). The main arm may include a first arm segment (110) connected to the support, a second curved arm segment (120) connected to the first arm segment (110), and a third arm segment (130) connected to the second arm segment (120). For the purposes of this exemplary embodiment, there is provided an exemplary cartesian coordinate system where a Z-axis denominates the vertical and a Y-axis and an X-axis denominates a horizontal plane. Typically, when the apparatus (100) is used during laparoscopy, the Z-axis may be the surgeon’s vertical, the X-axis may be horizontal and parallel relative to the surgeon, and the Y-axis may be horizontal and perpendicular relative to the surgeon. The first arm segment (110) may extend from the mounting structure (112) to a swivel joint (114) which may include a joint connection (114B), gears (114A), and a mount connection (118). The gears (114A) may be configured to rotate the joint connection (114B) about the Z-axis. The gears (114A) may include a yaw gear arrangement whereby the joint connection (114B) may be rotated about the Z-axis relative to the mount connection (118). The mount connection (118) may connect the gears (114A) to the mounting structure (112). Rotating the joint connection (114B) about the Z-axis may move the laparoscope (102) about the Z-axis when held by the carrier (140). The yaw degree of freedom of the laparoscope (102) may be the rotational movement of the laparoscope (102) about the Z-axis. Figure 2 is a three-dimensional view of the second curved arm segment (120) connected to the joint connection (114B) at one end and the third arm segment (130) at an opposite end. Figures 3 and 4 are enlarged views of the second curved arm segment (120). The main arm may include a pitch mechanism whereby the second curved arm segment (120) may be moved relative to the first arm segment (110). More specifically, the pitch mechanism may be configured to move the second curved arm segment (120) relative to the joint connection (114B). The pitch mechanism may include a pitch driver (124) and the second curved arm segment (120) may include a mating surface (122) configured to mate with the pitch driver (124). The pitch driver (124) may actuate or move the second curved arm segment (120) due to the mating arrangement with the second curved arm segment (120) when driven. In the embodiment shown, the pitch driver (124) may be a pinon (124), and the mating surface (122) on a curved body (126) of the second curved arm segment (120) may form a rack. The rack and pinion (124), when assembled, may form a rack and pinion arrangement. The joint connection (114B) may be configured to rotatably house the pinion (124) such that it is able to rotate within the housing. The joint connection (114B) may further include a groove (116) configured to receive the rack of the second curved arm segment (120). The rack and pinion (124) may mate when the pinion (124) is housed by the joint connection (114B) and the rack is positioned within the groove (116). Rotation of the pinion (124) may cause the rack to slide within the groove (116), causing the second curved arm segment (120) to move relative to the first arm segment (110). The curved body (126) may be configured to slide within the groove (116). Referring to Figure 4, when the pinion (124) is driven to rotate clockwise, the curved body (126) may slide within the groove (116) substantially from left to right in this view. When the pinion (124) is driven to rotate anti-clockwise, the curved body (126) may slide within the groove (116) substantially from right to left. Substantially from left to right should be understood to mean from a general left area to a general right area, and substantially from right to left should be understood to mean from a general right area to a general left area. It should be understood that the left-to-right or right-to-left movement does not need to be linear. The curvature of the second curved arm segment (120) may cause the second curved arm segment (120) to rotate about a virtual pivot point (PP) with a Z-Y plane. The rotation, or movement, of the second curved arm segment (120) may manipulate the pitch of the laparoscope (102) within the same plane. Therefore, the curvature of the second curved arm segment (120) may define a pitch path the laparoscope (102) may follow when moved by the apparatus (100). The curved body (126) may terminate with a stop (128) configured to prevent the body (126) from sliding out of the groove (116). Figures 5 and 6 illustrate a pitch range of the second curved arm segment (120). When the stop (128) abuts with the joint connection (114B), the second curved arm segment (120) may be at a first end of the pitch range and the laparoscope (102) may be substantially horizontal, as shown in Figure 5. When the opposite end of the curved body (126) is positioned within the groove (116), the second curved arm segment (120) may be at a second end of the pitch range and the laparoscope (102) may be pointing generally downwards, as shown in Figure 6. Substantially horizontal must not be understood to be exactly horizontal. Instead, it should be understood to be within 10 degrees from the horizontal. Similarly, pointing generally downwards must not be understood that the laparoscope is generally vertical, but that the laparoscope may be angled less than 20 degrees from the vertical, as determined by the requirements of the application. Figure 7 shows an enlarged view of the third arm segment (130) without the carrier (140). The third arm segment (130) may be connected to the second curved arm segment (120). The connection may include a portion of the second curved arm segment (120) and be integral to the third arm segment (130), as shown in Figure 7. In this embodiment, the connection may be detachable from the second curved arm segment (120). However, it may very well be that the third arm segment (130) is detachable from the connection, which is integral to the second curved arm segment (120). It may also be that the connection is a separate segment of the main arm which does not form an integral part of the second (120) or third (130) arm segments. The third arm segment (130) may include a carrier (140) which is more clearly shown in Figure 8. The third arm segment (130) may include a translation mechanism (132) configured to move the carrier (140). The translation mechanism (132) may include a belt (132B) and translation pulley (132A) which may be driven by a translation motor (134). The belt (132B) may engage with the carrier (140) such that the carrier (140) may move together with the belt (132B). The belt (132B) may include teeth (132C) which may engage with a cooperating carrier engagement (138) such that the carrier (140) may move with the belt (132B). The cooperating carrier engagement (138) may accept a portion of the belt (132B) and an internal engagement mechanism of the cooperating carrier engagement (138) may engage with the teeth (132C) to secure the carrier (140) to the belt (132B). It should be appreciated that there may be various different mechanisms and engagements to connect the carrier (140) to the translation mechanism (132), such as a rack and pinion, a chain and chain connection, a slot and key arrangement, and the like. The translation mechanism (132) may engage with the carrier (140) and may translate the carrier (140) along a laparoscope axis (L). The belt (132) and cooperating carrier engagement (138) should be understood to be exemplary and may be used in a preferred embodiment. Figure 8 shows an exemplary view of the laparoscope positioning apparatus (100) connected to the floor, controls (160, 170) for manually controlling the main arm, and an enlarged view of the carrier (140). The carrier (140) may include a laparoscope housing (141) configured to accept and hold the laparoscope (102). The carrier (140) may further include a roll mechanism configured to rotate the laparoscope (102) about the laparoscope axis (L-L). Rotating the laparoscope (102) about the laparoscope axis (L-L) may designate the roll movement of the laparoscope. The roll mechanism may include a roll motor (148) configured to power and drive first (142) and second (144) roll pulleys connected by a roll belt (146). The second roll pulley (144) may be configured to engage with the laparoscope (102), or an end thereof, such that they may rotate together. It should be appreciated that similar to the translation mechanism, there may be other roll mechanisms which do not include a belt and pulley arrangement. These roll mechanisms may include a gear arrangement, a motor and follower arrangement, or the like. However, the illustrated roll mechanism may be used in a preferred embodiment. Figure 9 is a simplified schematic view of the main arm of the laparoscope position apparatus (100) showing the different degrees of freedom the apparatus (100) provides. For the purposes of explaining the movement of the laparoscope (102) by the apparatus (100), the laparoscope may be received by the carrier (140) with the laparoscope axis (L-L) aligned with the Y-axis, the Z-axis being vertical and perpendicular to the Y-axis, and the X-axis being perpendicular to both the Y-axis and Z-axis. The laparoscope (102) may be movable in four degrees of freedom. The degrees of freedom may be pitch (P), yaw (Y), forwards-backwards (FB), and roll (R). The yaw (Y) movement may be by means of the movement of the swivel joint (114). More specifically, the yaw (Y) movement may be achieved by the rotation of the joint connection (114B) about the Z-axis as driven by the gears (114A). Rotating the joint connection (114B) may, in turn, rotate the second curved arm segment (120) and the third arm segment (130). This will cause the carrier (140) and the laparoscope (102), as held by the carrier (140), to rotate about the Z-axis, causing the yaw (Y) movement of the laparoscope. The pitch (P) movement may be by means of the translation of the second arm segment (120) relative to the swivel joint (114). More specifically, the pitch (P) movement may be achieved by the pitch driver (124) rotating and engaging with the mating surface (122) to translate the curved body (126) to slide within the groove (116), causing the second curved arm segment (120) to move relative to the first arm segment (110). The curvature of the curved body (126) may cause it and the third arm segment (130) with the carrier (140) and laparoscope (102) to rotate about the X-axis. Rotation of the laparoscope (102) about the X-axis by the main arm in the current orientation may cause the pitch (P) movement. The roll (R) movement may be by means of the rotation of the laparoscope (102) about its own axis (L-L). This may be by means of the roll mechanism being configured to engage with the laparoscope (102) while the carrier (140) holds it in the housing (141). The roll mechanism may be configured to drive the rotation of the laparoscope (102) about its own axis (L-L). As mentioned previously, to compensate for the rotation of the image caused by the rotation of the laparoscope, the system may digitally rotate the display image so as to reorient the image to the correct view point of the surgeon. The forwards-backwards (FB) movement may be by means of the translation of the laparoscope carrier (140) relative to the third arm segment (130). More specifically, the translation mechanism (132) of the third arm segment (130) may engage with the carrier (140) and may translate the carrier (140) along the laparoscope axis (L-L) and relative to the third arm segment (130). As the carrier (140) holds the laparoscope (102) it may move together with the carrier (140). Thereby, the laparoscope (102) may be translated in line with the Y-axis and, therefore, moved forwards-backwards. Figures 10 and 11 are examples of a laparoscope (102) which may be used in laparoscopy. The laparoscope (102) does not part of the laparoscope positioning apparatus (100) and it should be understood that the laparoscope (102) shown is only for illustrative and exemplary purposes. A distal end of the laparoscope (102) may be inserted into an abdomen during laparoscopy and a proximal end of the laparoscope (102) may be held by the carrier (140). The distal end may include a laparoscopic camera (104) and associated lighting which, in use, captures the insides of an abdomen. Figure 12 shows a three-dimensional view of the laparoscope positioning apparatus (100) in use with a test abdomen (20). The test abdomen (20) simulates a body lying on an operation table during laparoscopy. The test abdomen (20) includes multiple access points (22 and 24) simulating insertions made to access the insides of the abdomen during laparoscopy. One of the access points is a laparoscope access point (22) and the others are instrument access points (24). Figure 12 shows the distal end of the laparoscope (102) inserted into the test abdomen (20) via the laparoscope access point (22). The proximal end is held by the carrier (140) and the laparoscope positioning apparatus (100) is connected to a support which may be the operation table. Figure 13 shows the laparoscope positioning apparatus (100) as used with surgical instruments or tools (30 and 40). During laparoscopy, a surgeon typically uses two surgical instruments, i.e. a left instrument (30) and a right instrument (40). Figure 13 shows how the apparatus (100) may control the movement of the laparoscope (102) during laparoscopy. A surgeon may hold the instruments (30 and 40) such that distal ends thereof may be in the field of view of the laparoscope (102) and that the distal ends may be recorded. The laparoscope is connected to a control system, which may include a processor and memory that is integral with the apparatus (100) or may be provided by a computing system used in conjunction with the apparatus (100). The control system is configured to receive video data from the laparoscope and to identify at least one surgical instrument (30, 40) visible within the field of view of the laparoscope (102). Typically, two surgical instruments are used in laparoscopy in conjunction with the laparoscope, a surgical tool such as a trocar or grasper, and a suction tube. The at least one of the surgical instruments (30, 40) may include a marker (32, 42) by which the control system may identify the surgical instrument (30, 40). The marker (32,42) may be a pattern, a colour marker, a distinguishable shape, a scratch, an indent, a protrusion, or anything that is distinguishable from the surroundings during laparoscopy. In a preferred embodiment, the marker may be a colour marker. The instrument (30, 40) is identifiable by the control system. It may be that only the left instrument (30) includes a marker (32) or that only the right instrument (40) includes a marker (42). It may also be that both instruments (40, 30) have markers (42, 32). It may also be that the markers (32, 42) are distinct such that the control system can distinguish between the left instrument (30) and the right instrument (40). Figures 14 to 20 are exemplary illustrations of a field of view (50) of the laparoscope (102) as displayed on a screen to a surgeon during laparoscopy. The field of view (50) may be the field of view of the laparoscope (102) as held and controlled by the laparoscope position apparatus (100) of Figure 13. The control system may be configured to identify two surgical instruments (30, 40) visible within the field of view (50). The field of view (50) may include a centre point (51) and a focal area (52). The centre point (51) may be the centre of the two surgical instruments (30, 40) and it may be that the surgeon desires the centre point (51) to be in the focal area (52). More specifically, the centre point may be the centre between the two markers (32, 42). The focal area (52) may be a virtual area (52) which may be displayed on the screen and may be designated by digital boundaries. The focal area (52) may be the centre of the field of view (50). The field of view (50) may also include one or more virtual bands or zones (53, 54) for aligning the laparoscope (102) such that a portion thereof or the markers (32, 42) remain within the bands or zones (53, 54). These bands may or may not be visible in the display. The field of view (50) may have a band (53, 54) for each instrument (30, 40) the control system identifies. In the case where the control system identifies one instrument (30, 40), the field of view may only have one band or zone (53, 54). However, in the preferred embodiment, the control system may be configured to identify two instruments (30, 40) and the field of view (50) may therefore include two bands or zones (53, 54). The control system may control the laparoscope positioning apparatus (100) to position the laparoscope (102) such that the left instrument (30) remains within a left band (53) and the right instrument (40) remains within a right band (54). More specifically, the control system may control the laparoscope positioning apparatus (100) to position the laparoscope (102) such that the left instrument marker (32) remains within the left band (53) and the right instrument marker (42) remains within the right band (54). It should be appreciated that even though bands (53, 54) are used in the exemplary field of view (50), the zones may not be bands. For example, the zones may be blocks, circles, trapezoids, diamonds, or any other shaped zones. It is important that there may be zones and that the zones may be used to manoeuvre the apparatus (100) such that the instruments (30, 40), or a portion thereof, remain within the zones. The control system may be configured to control the apparatus (100) such that each marker (32, 42) may be within its designated band (53, 54) in the field of view (50) and that the markers (32, 42) substantially align with the centre of the focal area (52), as illustrated in Figure 14. Therefore, the control system may control the apparatus such that the centre point (51) is positioned within the centre of the focal area (52). For example, when the centre point (51) is above or below the focal area (52), as illustrated in Figures 15 and 16, the apparatus (100) may be controlled to adjust the position of the laparoscope (102) such that centre point (51) is substantially in the centre of the focal area (52), thereby moving the field of view (50) up or down. Similarly, when the centre point (51) is left or right of the focal area (52) or the centre of the focal area (52), as illustrated in Figures 17 or 18, the apparatus (100) may be controlled to adjust the position of the laparoscope (102) such that centre point (51) is substantially in the centre of the focal area (52), thereby moving the field of view (50) left or right. When the markers (32, 42) are outside of the bands (53, 54), as illustrated in Figure 19, the laparoscope (102) may be moved further away from the markers (32, 42) or an area of interest until the markers (32, 42) are aligned with the bands (53, 54). Similarly, when the markers (32, 42) are between the bands (53, 54), as illustrated in Figure 20, the laparoscope (102) may be moved closer to the markers (32, 42) or an area of interest until the markers (32, 42) are aligned with the bands (53, 54). Moving the laparoscope (102) further away from or closer to the markers (32, 42) may be a zoom-in and a zoom-out action. The control system may be switched or toggled between an active state and an inactive state. In the active state, the pitch, yaw, roll, and translation may automatically be controlled by the control system based on the movement and position of the one or more instruments (30, 40) relative to the laparoscope (102). Therefore, in the active state, the surgeon may be able to control the position of the laparoscope (102) simply by moving the surgical instruments (30, 40). On the other hand, in the inactive state, the control system may be configured to keep the laparoscope (102) still and stable regardless of any instrument (30, 40) movements. Returning to Figure 8, the laparoscope positioning apparatus (100) and control system may be connected to a controller such as a remote controller. In a preferred embodiment, the controller may be a foot controller (170). The foot controller (170) may include user inputs such as push buttons, toggle switches, joysticks, or the like. The foot controller (170) may be for controlling the roll (R) of the laparoscope (102) when held by the carrier (140). The foot controller (170) may further be configured to receive a user input for adjusting the orientation of the field of view (50). The foot controller may also be used to switch the control system between the active state and the inactive state. During laparoscopy, the surgeon may move the instruments (30, 40) such that one can be higher or lower than the other within the field of view (50). When the control system is in the active state, it may control the apparatus (100) to move the laparoscope (102) to follow the instruments (30, 40) such that the surgeon may keep viewing them. During movement of the instruments (30, 40), the control system may cause the image in the video feed to rotate such that the instruments (30, 40) or the markers (32, 42) remain within the bands (53, 54) and the centre point (51) remains substantially at the centre of the focal area (52). In some instances (e.g. where the laparoscope is physically rotated), the perspective of the camera relative to the surgeon’s hands will change. The surgeon viewing the screen may be disorientated as the display may show the instruments in a different orientation than that in which the surgeon is holding them. To compensate for this, the surgeon may therefore toggle an orientation input, button or switch on the foot controller (170) to instruct the control system to adjust the orientation of the field of view (50) as displayed on the screen by rolling / rotating clockwise or anticlockwise, as desired. In one example, there may only be a foot controller (170). Using the apparatus (100) with only a foot controller (170) for laparoscopy may enable the surgeon to conduct the procedure on his or her own. Therefore, an assistant may not be required for the procedure. In an alternative embodiment, the controller may be a hand controller (160) which may include user inputs such as push buttons, toggle switches, joysticks, or the like. Each user input may be associated with manipulating a segment of the main arm. For example, a first user input may instruct the control system to control the movement of the first arm segment (110) to control the yaw (Y) of the main arm and the laparoscope (102). Similarly, a second user input may instruct the control system to control the movement of the second curved arm segment (120) to control the pitch (P) of the main arm and laparoscope (102). A third user input may instruct the control system to control the movement of the third arm segment (130) to control the forward-backward (FB) movement of the laparoscope (102). A fourth user input may instruct the control system to control the roll (R) of the laparoscope (102) while held in the carrier (140). There may be two user inputs for each of the pitch (P), yaw (Y), forwards-backwards (FB) and roll (R) movements of the laparoscope (102) The first of the two user inputs may be for movement in a first direction and a second of the two user inputs may be for a movement in an opposite direction. The control system may be configured to receive instructions from the hand controller (160) during the inactive state and manipulate the main arm based on the instructions. The hand controller (170) may, in the further embodiment, be used in conjunction with the foot controller (160). It may give an assistant control over the laparoscope positioning apparatus (100). The hand controller (170) may be useful as a failsafe, for example, where the control system malfunctions or is not accurate enough when attempting to move the laparoscope (102). Alternatively, it may be useful to give a teacher control over the laparoscope during training sessions when training a trainee surgeon, for example. However, as mentioned earlier, in one embodiment (which may be the preferred embodiment), only a foot controller may be present. Figure 21 is a block diagram showing steps of a method (200) for controlling a position of a laparoscope during laparoscopy, the method (200) being performed by a control system. The method (200) includes receiving (202) video data from a laparoscope held by a laparoscope positioning apparatus, the laparoscope positioning apparatus including a number of movable arm segments connected together by which a position of the laparoscope can be changed. The method (200) further includes analysing (202) the video data to identify at least one surgical instrument visible within a field of view of the laparoscope. The control system may identify a marker on the at least one surgical instrument. More specifically, the video data may be analysed to identify two surgical instruments visible within the field of view of the laparoscope. The method includes controlling (206) movement of the arm segments so as to change the position of the laparoscope based on the relative position of the at least one surgical instrument in the field of view. More specifically, controlling the movement of the arm segments may be based on the relative position of the marker in the field of view. The movement of the arm segments may be controlled to position the laparoscope so that a focal area may be centred between the two surgical instruments. The focal area may be an area of interest a surgeon is focussing on, such as an appendix during an appendectomy. The method (200) may further include changing the position of the laparoscope by moving it closer to or further away from the two surgical instruments so that both surgical instruments may remain within the field of view. The position of the laparoscope may be changed so that each surgical instrument remains within a band or zone offset from a centre of the field of view. The method may further include moving one of the arm segments to change the position of the laparoscope within a degree of freedom associated with that arm segment. Moving the main arm may include changing a yaw of the laparoscope by means of movement of a swivel joint and a first arm segment. The first arm segment may be extending from a mounting structure to the swivel joint. Moving the main arm may include changing a pitch of the laparoscope by translating a second arm segment relative to the swivel joint. The second arm segment may be connected to the swivel joint. Moving the main arm may further include moving the laparoscope forwards-backwards by translating a carrier on a third arm segment connected to the second arm segment. The carrier may be holding the laparoscope. Lastly, moving the main arm may include rotating the laparoscope by the carrier about its own axis, while rotation may also be achieved virtually by rotation of the displayed video data rather to reorient the display to the correct point of view. The method may include automatically controlling any one or more of the degrees of freedom when the control system is in an active state. More specifically, the method may include switching the control system between the active state and an inactive state by means of a second foot controller. The method (200) may be implemented by a control system controlling a laparoscope positioning apparatus (100) holding a laparoscope (102) as explained earlier. An advantage of the control system, method (200), and laparoscope positioning apparatus (100) is that the surgeon can attend to a laparoscopy without the use of an assistant controlling a laparoscope and without having to release one of the instruments. The laparoscope positioning apparatus (100) is able to identify at least one surgical instrument and manipulate and change the position of the laparoscope such that the at least one surgical instrument remains within the field of view of the laparoscope. Furthermore, if the surgeon requires manual control over the movement of the laparoscope, or for certain movements like, there may be provided a foot controller whereby the surgeon can adjust the laparoscope position. The control system may be toggled between an active and inactive state. The surgeon can be assured that the field of view may remain constant while performing fine surgical movements while the control system is in the inactive state, thereby keeping the laparoscope still while performing the fine movements. When the surgeon wishes to change the field of view, all that is required is to activate a foot controller to change the control system into the active state, and then move the surgical tools to guide the field of view of the laparoscope. Another advantage of the laparoscope positioning apparatus is the compact structure of the main arm. The main arm may be positioned between the surgeon and a body during a laparoscopy. As the main arm is compact, the centre of gravity may remain substantially below a connection of the apparatus to support. Having the centre of gravity at a substantially constant point reduces the variable loads gravity imparts on the apparatus when moving the different arm segments. This increases the stability of the apparatus. The foregoing description has been presented for the purpose of illustration; it is not intended to be exhaustive or to limit the technology to the precise forms disclosed. Persons skilled in the relevant art can appreciate that many modifications and variations are possible in light of the above disclosure. The language used in the specification has been principally selected for readability and instructional purposes, and it may not have been selected to delineate or circumscribe the inventive subject matter. It is therefore intended that the scope of the present disclosure be limited not by this detailed description, but rather by any claims that issue on an application based hereon. Accordingly, the present disclosure is intended to be illustrative, but not limiting, of the scope of any accompanying claims. Finally, throughout the specification and any accompanying claims, unless the context requires otherwise, the word ‘comprise’ or variations such as ‘comprises’ or ‘comprising’ will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

Claims

1. A laparoscope positioning apparatus comprising:a main arm having a first end with a mounting structure for attaching the main arm to a support, and an opposite second end having a carrier for holding a laparoscope;wherein the main arm includes a number of movable arm segments connected together by which a position of the laparoscope can be changed;and wherein movement of the arm segments is controlled by a control system which receives video data from the laparoscope, identifies at least one surgical instrument visible within a field of view of the laparoscope, and changes the position of the laparoscope based on the relative position of the at least one surgical instrument in the field of view.

2. The laparoscope positioning apparatus as claimed in claim 1, wherein the control system identifies two surgical instruments visible within the field of view of the laparoscope.

3. The laparoscope positioning apparatus as claimed in claim 2, wherein the control system changes the position of the laparoscope so that a focal area is generally centred between the two surgical instruments.

4. The laparoscope positioning apparatus as claimed in claim 2 or claim 3, wherein the control system changes the position of the laparoscope by moving it closer to or further away from the two surgical instruments so that both surgical instruments remain within the field of view.

5. The laparoscope positioning apparatus as claimed in any one of claims 2 to 4, wherein the control system changes the position of the laparoscope so that each surgical instrument remains within a band or zone offset from a centre of the field of view.

6. The laparoscope positioning apparatus as claimed in any one of claims 1 to 5, wherein the arm segments include a first arm segment extending from the mounting structure to a swivel joint, a second curved arm segment movable in translation relative to the swivel joint, and a third arm segment connected to the second arm segment and having a laparoscope carrier movable in translation relative to the third arm segment.

7. The laparoscope positioning apparatus as claimed in claim 6, wherein the laparoscope carrier also rotates the laparoscope about its own axis.

8. The laparoscope positioning apparatus as claimed in claim 7, wherein the position of the laparoscope is movable in four degrees of freedom being pitch, yaw, roll and forwards-backwards, with pitch by means of the translation of the second arm segment relative to the swivel joint, yaw by means of the movement of the swivel joint, roll by means of the rotation of the laparoscope about its own axis, and forward-backwards by means of the translation of the laparoscope carrier.

9. The laparoscope positioning apparatus as claimed in claim 8, wherein any one or more of the degrees of freedom are controlled manually by means of a first foot controller.

10. The laparoscope positioning apparatus as claimed in claim 8 or claim 9, wherein pitch, yaw and roll is controlled automatically by the control system when the control system is in an active state.

11. The laparoscope positioning apparatus as claimed in claim 10, wherein the control system is switched between the active state and an inactive state by means of a second foot controller.

12. The laparoscope positioning apparatus as claimed in any one of the preceding claims, wherein the at least one surgical instrument includes a marker by which the control system identifies the surgical instrument.

13. The laparoscope positioning apparatus as claimed in any one of the preceding claims, wherein the control system controls a display orientation of the video data and enables such orientation to be rotated to reorient an on-screen image to compensate for roll movement of the laparoscope.

14. A method of controlling a position of a laparoscope during laparoscopic surgery, comprising, by means of a control system:receiving video data from a laparoscope held by a laparoscope positioning apparatus, the laparoscope positioning apparatus including a number of movable arm segments connected together by which a position of the laparoscope can be changed;analysing the video data to identify at least one surgical instrument visible within a field of view of the laparoscope; andcontrolling movement of the arm segments so as to change the position of the laparoscope based on the relative position of the at least one surgical instrument in the field of view.

15. The method as claimed in claim 14, including identifying a marker on the at least one surgical instrument and controlling the movement of the arm segments based on the relative position of the marker in the field of view.

16. The method as claimed in claim 14 or claim 15, wherein the video data is analysed to identify two surgical instruments visible within the field of view of the laparoscope.

17. The method as claimed in claim 16, including controlling the movement of the arm segments to position the laparoscope so that a focal area is generally centred between the two surgical instruments.

18. The method as claimed in claim 16 or claim 17, including changing the position of the laparoscope by moving it closer to or further away from the two surgical instruments so that both surgical instruments remain within the field of view.

19. The method as claimed in any one of claims 14 to 18, wherein the position of the laparoscope is changed so that each surgical instrument remains within a band or zone offset from a centre of the field of view.

20. The method as claimed in any one of claims 14 to 19, including moving one of the arm segments to change the position of the laparoscope within a degree of freedom associated with that arm segment.

21. The method as claimed in claim 20, including changing a yaw of the laparoscope by means of movement of a swivel joint and a first arm segment, the first arm segment extending from a mounting structure to the swivel joint; changing a pitch of the laparoscope by translating a second arm segment, connected to the swivel joint, relative to the swivel joint; moving the laparoscope forwards-backwards by translating a carrier on a third arm segment connected to the second arm segment, the carrier holding the laparoscope; and rotating the laparoscope about its own axis with the carrier.

22. The method as claimed in claim 21, including manually controlling the rotation of the laparoscope about its own axis by means of a first foot controller, and optionally causing a display orientation of the video data to rotate so as to reorient an on-screen image to compensate for the rotation of the laparoscope.

23. The method as claimed in claim 21 or claim 22, including automatically controlling the pitch, yaw and rotation when the control system is in an active state.

24. The method as claimed in claim 23, including switching the control system between the 5 active state and an inactive state by means of a second foot controller.

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