Abstract:
The present invention relates to a minimally invasive surgical instrument implementing a motor. According to one embodiment of the present invention, a minimally invasive surgical instrument comprises a shaft, an end effector connected to one end of the shaft, and a handle unit connected to the other end of the shaft. The handle unit includes a pair of linearly moving members, at least one rotating member for moving the pair of linear moving members away from each other in opposite directions, and a driving element for driving said at least one rotating member. The pair of linearly moving members operates the end effector in the pitch direction or in the yaw direction.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a minimally invasive surgical instrument implemented with a motor. 
       BACKGROUND 
       [0002]    Minimally invasive surgery is a surgical approach that involves the use of instruments inserted through several tiny incision openings to perform a surgery causing minimal tissue trauma in human or animal bodies. 
         [0003]    The minimally invasive surgery relatively reduces changes in metabolism of a patient in the period of post-surgical care, so it facilitates rapid recovery of the patient. Therefore, the minimally invasive surgery shortens the length of hospitalization of the patient after the surgery and allows the patient to return to normal physical activities in a short period of time. In addition, the minimally invasive surgery causes less pain and leaves fewer scars on the patient&#39;s body after the surgery. 
         [0004]    One of the general forms of the minimally invasive surgery is endoscopy. Among the others, a laparoscopy that involves minimally invasive inspection and operation inside abdominal cavity is known as the most general form of endoscopy. To operate a standard laparoscopic surgery, the abdomen of the patient is insufflated with gas and at least one small incision is formed to provide an entrance for laparoscopic surgical instruments, through which a trocar is inserted. When performing the surgery, it is general that a user puts the laparoscopic surgical instruments into a surgical site or the like through the trocar, and manipulates (or controls) the instruments from the outside of abdominal cavity. In general, the laparoscopic surgical instruments include a laparoscope (for observation of a surgical site) and other working tools. Herein, the working tools are similar to the conventional tools used for small incision surgery, except that the end effector or working end of each tool is separated from its handle or the like by a shaft. For instance, the working tools may include a clamp, a grasper, scissors, a stapler, a needle holder, and so forth. Meanwhile, the user monitors the procedure of the surgery through a monitor that displays the images of the surgical site which are taken by the laparoscope. The endoscopic approaches similar to the above are broadly used in retroperitoneoscopy, pelviscopy, arthroscopy, cisternoscopy, sinuscopy, hysteroscopy, nephroscopy, cystoscopy, urethroscopy, pyeloscopy, and so on. 
         [0005]    The inventor(s) has developed various minimally invasive surgical instruments useful for the above-mentioned minimally invasive surgeries and has already disclosed the features of the structures and effects of the same in Korean Patent Application Nos. 2008-51248, 2008-61894, 2008-79126 and 2008-90560, the contents of which are incorporated herein by reference in its entirety. Additionally, the inventor(s) have also introduced a minimally invasive surgical instrument with improved functionality, which is more advantageous for users and patients, in Korean Patent Application Nos. 2010-115152, 2011-3192, 2011-26243 and 2011-29771, the contents of which are incorporated herein by reference in its entirety. 
         [0006]    Herein, the inventor(s) now present a minimally invasive surgical instrument that may employ a motor and that a user may hold and manipulate more conveniently than those disclosed in the above Korean applications or others. 
       SUMMARY OF THE INVENTION 
       [0007]    One object of the present invention is to provide a minimally invasive surgical instrument that may employ a motor and that a user may hold and manipulate more conveniently. 
         [0008]    Another object of this invention is to provide a minimally invasive surgical instrument that may be easily combined with a separate system (e.g., a surgical robot system). 
         [0009]    Yet another object of this invention is to provide a minimally invasive surgical instrument wherein mechanical instability is minimized. 
         [0010]    According to one aspect of the invention to achieve the objects as described above, there is provided a minimally invasive surgical instrument comprising a shaft; an end effector being connected to one end of the shaft; and a handling unit being connected to the other end of the shaft, wherein the handling unit comprises a pair of linear motion members; at least one rotating member to allow the pair of linear motion members to move in the opposite directions; and a driving element to drive the at least one rotating member, and wherein the pair of linear motion members operates the end effector in a pitch or yaw direction. 
         [0011]    In addition, there may be provided other configurations to implement this invention. 
         [0012]    According to the invention, there is provided a minimally invasive surgical instrument that may employ a motor and that a user may hold and manipulate more conveniently. 
         [0013]    According to the invention, there is provided a minimally invasive surgical instrument that may be easily combined with a separate system (e.g., a surgical robot system). 
         [0014]    According to the invention, there is provided a minimally invasive surgical instrument wherein mechanical instability is minimized. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]      FIG. 1  shows the overall appearance of a minimally invasive surgical instrument according to one embodiment (a first embodiment) of the invention. 
           [0016]      FIG. 2  is a front view of a handling unit  400  of the minimally invasive surgical instrument shown in  FIG. 1 , and  FIG. 3  is a rear view of the handling unit  400  of the minimally invasive surgical instrument shown in  FIG. 1 . 
           [0017]      FIG. 4  shows some components of the handling unit  400  of the minimally invasive surgical instrument according to one embodiment of the invention. 
           [0018]      FIG. 5  is a cross-sectional view of some components of the handling unit  400  of the minimally invasive surgical instrument shown in  FIG. 4 . 
           [0019]      FIG. 6  is a perspective view of some components of the handling unit  400  of the minimally invasive surgical instrument shown in  FIG. 4 . 
           [0020]      FIG. 7  is a perspective view of a second rotating member  432 , and 
           [0021]      FIG. 8  is a perspective view of one linear motion member  480 . 
           [0022]      FIG. 9  is an exploded perspective view of some components of the handling unit  400  of the minimally invasive surgical instrument according to one embodiment of the invention. 
           [0023]      FIG. 10  shows in detail a multifunction manipulation unit  410  of the handling unit  400  of the minimally invasive surgical instrument according to one embodiment of the invention. 
           [0024]      FIG. 11  shows a handling unit  400 ′ of a minimally invasive surgical instrument according to another embodiment (a second embodiment) of the invention. 
           [0025]      FIG. 12  shows a first section  430 ′ of the handling unit  400 ′, and 
           [0026]      FIG. 13  shows the (internal) components of the first section  430 ′ shown in  FIG. 12 . 
           [0027]      FIG. 14  shows the (internal) components of a second section  440 ′ of the handling unit  400 ′, and 
           [0028]      FIG. 15  shows some components thereof. 
           [0029]      FIG. 16  shows the operation of the handling unit  400 ′ of the minimally invasive surgical instrument according to another embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0030]    In the following detailed description of the invention, references are made to the accompanying drawings that show, by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. It is to be understood that the various embodiments of the invention, although different from each other, are not necessarily mutually exclusive. For example, specific shapes, structures, or characteristics described herein may be implemented as modified from one embodiment to another embodiment without departing from the spirit and the scope of the invention. Furthermore, it shall be understood that the locations or arrangements of individual elements within each embodiment may be also modified without departing from the spirit and the scope of the invention. Therefore, the following detailed description is not to be taken in a limiting sense, and the scope of the invention is to be taken as encompassing the scope of the appended claims and all equivalents thereof. In the drawings, like reference numerals refer to the same or similar elements throughout the several views. 
         [0031]    Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings to enable those skilled in the art to easily implement the invention. 
         [0032]    Meanwhile, it should be understood that the term “connection” herein encompasses a direct connection or an indirect connection (i.e., via separate components) between mechanical or other types of components. For example, a connection between two rotating components may be a direct connection by the engagement of corresponding gear elements or the like, but may also be an indirect connection via a separate component such as a cable or another rotating component. 
       First Embodiment 
       [0033]      FIG. 1  shows the overall appearance of a minimally invasive surgical instrument according to one embodiment (a first embodiment) of the invention. 
         [0034]    Reference will be made to  FIG. 1 . The minimally invasive surgical instrument may comprise a shaft  100 ; an end effector  200  being connected to one end of the shaft  100  to perform surgery by using surgical tools (not shown) or functioning itself as a surgical tool; a joint unit  300  to connect the shaft  100  and the end effector  200  and to provide the end effector  200  with joint functionality; and a handling unit  400  being connected to the other end of the shaft  100  and capable of being held and manipulated by a user. 
         [0035]    First, the shaft  100  may include a cavity therein to support and pass at least one wire or torque transmission member, in the same manner as those of the minimally invasive surgical instruments disclosed in the aforementioned Korean patent applications of the applicant(s). (The torque transmission member is mainly intended for the rolling motion of the end effector  200 , while the shaft  100  may function itself as the torque transmission member in some cases.) The shaft  100  may comprise at least one segment as necessary. Further, the shaft  100  may comprise a bend in at least a part thereof. 
         [0036]    Next, the end effector  200  may carry out joint motion, rolling motion, opening/closing motion and the like by the action of the at least one wire or torque transmission member passing from the handling unit  400  to the joint unit  300  via the shaft  100 , in the same manner as those of the minimally invasive surgical instruments disclosed in the aforementioned Korean patent applications of the applicant(s). The tip of the end effector  200  may be implemented in the form of a clamp, a grasper, a pair of scissors, a stapler, a needle holder, a hook-type electrode or the like. 
         [0037]    Next, the joint unit  300  may act together with the at least one wire or torque transmission member to allow the end effector  200  to carry out joint motion, rolling motion and the like, in the same manner as those of the minimally invasive surgical instruments disclosed in the aforementioned Korean patent applications of the applicant(s). 
         [0038]    Finally, the handling unit  400  may control the joint motion, rolling motion, opening/closing motion and the like of the end effector  200  according to the user&#39;s manipulation, in the same manner as those of the minimally invasive surgical instruments disclosed in the aforementioned Korean patent applications of the applicant(s). To allow for such control, the at least one wire or torque transmission member may be connected to the handling unit  400 . Further, the handling unit  400  may comprise a multifunction manipulation unit  410  and a trigger  420  to allow the user to carry out various manipulations as will be described below. In addition, a power cord  490  may be connected to the handling unit  400  to supply power for driving at least one driving element (e.g., an electric motor) that may be included in the handling unit  400 . 
         [0039]      FIG. 2  is a front view of the handling unit  400  of the minimally invasive surgical instrument shown in  FIG. 1 , and  FIG. 3  is a rear view of the handling unit  400  of the minimally invasive surgical instrument shown in  FIG. 1 . 
         [0040]    Further reference will be made to  FIGS. 2 and 3 . In the handling unit  400 , the multifunction manipulation unit  410  may be disposed at the position to enable the user to conveniently manipulate the handling unit  400  using only one finger (e.g., thumb) while holding it with the right hand. It is apparent that the multifunction manipulation unit  410  may also be disposed in the handling unit  400  to be suitable for the left-hand grip as necessary. Therefore, the user may use a set of minimally invasive surgical instruments for the right-hand and left-hand grip in some cases. 
         [0041]      FIG. 4  shows some components of the handling unit  400  of the minimally invasive surgical instrument according to one embodiment of the invention. 
         [0042]    Reference will be made to  FIG. 4 . The handling unit  400  may comprise a first gear  430 , a second gear  440 , a guide  450 , a first rotating member  460  and a first driving element  470 . Further, an external driving element  900  may be connected to the outer circumference of the first or second gear  430  or  440  as necessary. 
         [0043]    First, the first and second gears  430  and  440  may be disposed and rotate along the outer circumference of the handling unit  400  (at least a part of which is preferably cylindrical). The first or second gear  430  or  440  may have a gear element at the inner circumference thereof or at the inner and outer circumferences thereof. Meanwhile, the first and second gears  430  and  440  may be disposed substantially parallel to each other. 
         [0044]    Next, the guide  450  may be configured in the form of a cone, hemisphere or pyramid, or in the form similar to one or more of the foregoing, so that a pitch wire (not shown) and a yaw wire (not shown) from linear motion members to be described below and an opening/closing wire or a torque transmission member to be described below may be guided to the cavity of the shaft  100 . As descried above, the above wires or torque transmission member may act on the joint unit  300  or the end effector  200  to cause the joint motion, rolling motion, opening/closing motion and the like of the end effector  200 . 
         [0045]    Next, the first rotating member  460  may be driven by the first driving element  470  to be described below to allow the rotation of a torque transmission member that may be connected to one end thereof not shown in the drawing. To this end, the first rotating member  460  may have a gear element for connection to the first driving element  470  at one end thereof shown in the drawing. 
         [0046]    Finally, at least a part of the first driving element  470  may be an electric motor. The electric motor may be driven by the power supplied through the power cord  490 . The first driving element  470  may have a gear element for connection to the first rotating member  460  at one end thereof shown in the drawing. 
         [0047]      FIG. 5  is a cross-sectional view of some components of the handling unit  400  of the minimally invasive surgical instrument shown in  FIG. 4 . 
         [0048]    Further reference will be made to  FIG. 5 . A second rotating member  432  and a third rotating member  436 , which are paired to each other, may be connected to the inner circumference of the first gear  430 . To this end, the second and third rotating members  432  and  436  may have gear elements as shown in the drawing. Therefore, the second and third rotating members  432  and  436  may always rotate at substantially the same angular velocities with respect to each other as at least one (preferably, only one) of them is driven by a driving element such as an electric motor (not shown but may be referred to as a second driving element). Further, the second and third rotating members  432  and  436  may rotate together according to the rotation of the first gear  430  being connected with and driven by the external driving element  900 . To this end, the external driving element  900  may have a gear element as shown in the drawing. 
         [0049]    Meanwhile, although the first gear  430  and the associated components have been mainly described above, those skilled in the art will understand that the second gear  440  and the associated components (not shown but may be referred to as a fourth rotating member, a fifth rotating member, a third driving element and the like for convenience) may also have the same configurations. The first and second gears  430  and  440  (as well as the pair of the second and third rotating members  432  and  436  and the pair of the fourth and fifth rotating members) may rotate independently of each other to cause the independent operations of the pitch wire and yaw wire (or the yaw wire and pitch wire), respectively, according to the unique principle of the present invention to be described below. 
         [0050]      FIG. 6  is a perspective view of some components of the handling unit  400  of the minimally invasive surgical instrument shown in  FIG. 4 .  FIG. 7  is a perspective view of the second rotating member  432 , and  FIG. 8  is a perspective view of one linear motion member  480 . 
         [0051]    Further reference will be made to  FIGS. 6 to 8 . Under the condition shown in  FIG. 6 , the second and third rotating members  432  and  436  may allow each of a pair of linear motion members  480  to carry out forward and backward motion via a spiral part to be described below. In this case, each of the pair of linear motion members  480  may carry out forward and backward motion in the opposite directions and at substantially the same distance with respect to each other while grasping the pitch wire (or yaw wire) (or passing the pitch wire (or yaw wire)). Therefore, the pair of linear motion members  480  may control the joint unit  300  to cause the pitch direction (or yaw direction) operation of the end effector  200 . In connection with the principle thereof, further reference may be made to those disclosed in the aforementioned Korean patent applications, particularly Korean Patent Application No. 2010-115152. 
         [0052]    As shown in  FIG. 7 , a spiral part  433  may be connected or coupled to the second rotating member  432 . Further, as shown in  FIG. 8 , one linear motion member  480  corresponding to the second rotating member  432  may comprise a wire fixing part  482  and a spiral part  483 . In this case, each of the spiral part  433  and the corresponding spiral part  483  may have a spiral structure to allow the spiral part  483  to approach or go away from the spiral part  433  according to the rotation of the spiral part  433 . Further, a corresponding spiral part may also be connected or coupled to the third rotating member  436 , and another corresponding linear motion member  480  may comprise a corresponding wire fixing part  482  and a corresponding spiral part  483 . However, the spiral orientation of the spiral part  433  of the second rotating member  432  is opposite to that of the corresponding spiral part of the third rotating member  436 , and this also applies to the pair of spiral parts  483  of the pair of linear motion members  480 . Thus, when the distance between the second rotating member  432 , which may be fixed in the handling unit  400 , and the corresponding linear motion member  480  is decreased (i.e., when the corresponding linear motion member  480  carries out backward motion in the direction away from the end effector  200 ), the distance between the third rotating member  436  and the corresponding linear motion member  480  is increased (that is, the corresponding linear motion member  480  carries out forward motion in the direction toward the end effector  200 ), and vice versa. Therefore, the pitch wire (or yaw wire) that the pair of wire fixing parts  482  of the pair of linear motion members  480  are grasping or at least passing may cause the above-described joint motion. 
         [0053]      FIG. 9  is an exploded perspective view of some components of the handling unit  400  of the minimally invasive surgical instrument according to one embodiment of the invention. 
         [0054]    Reference will be made to  FIG. 9 . The first rotating member  460  may be driven by the first driving element  470  to rotate while holding a torque transmission member  700 . In connection with the specific configuration of the torque transmission member  700 , further reference may be made to those disclosed in the aforementioned Korean patent applications, particularly Korean Patent Application No. 2011-29771. 
         [0055]    Meanwhile, an opening/closing wire  800  may preferably be passed through the interior of the torque transmission member  700 . As the opening/closing wire  800  is pulled or released, the end effector  200  may carry out opening/closing motion as disclosed in the aforementioned Korean patent applications. 
         [0056]      FIG. 10  shows in detail a multifunction manipulation unit  410  of the handling unit  400  of the minimally invasive surgical instrument according to one embodiment of the invention. As shown in  FIG. 10 , the multifunction manipulation unit  410  may comprise a joint manipulation unit  412 , a rolling manipulation unit  414  and a fixing part  416 . 
         [0057]    First, the joint manipulation unit  412  may be manipulated in at least four directions (or in at least eight directions) in a manner similar to a joystick to control the pitch direction operation, yaw direction operation or bidirectional operation of the end effector  200 . Further, the joint manipulation unit  412  may be pushed or released like a button to fix or release the joint motion state of the end effector  200 . To this end, the handling unit  400  may further comprise an electronic circuit board (e.g., a printed circuit board) (not shown) for electronically detecting the direction in which the joint manipulation unit  412  is manipulated or whether it is pushed or not to drive or fix the above-described second or third driving element. It is apparent that the electronic circuit board may be readily implemented using known techniques. 
         [0058]    Next, the rolling manipulation unit  414  may preferably be implemented in the form of a wheel to control the rolling motion of the end effector  200 . To this end, the handling unit  400  may further comprise an electronic circuit board (e.g., a printed circuit board) (not shown) for electronically detecting the rotation of the rolling manipulation unit  414  to drive the above-described first driving element  470 . It is apparent that the electronic circuit board may also be readily implemented using known techniques. 
         [0059]    Finally, the fixing part  416  may provide electrical connections required for the above-described electronic configurations and mechanically fix the multifunction manipulation unit  410  to the handling unit  400 . 
         [0060]    Meanwhile, the trigger  420 , which is shown in  FIGS. 1 and 2  but not described in detail, will be discussed below. The trigger  420  may control the pulling or release of the opening/closing wire  800 . For example, when the trigger  420  is pushed, the opening/closing wire  800  may be fixed in a pulled state (thus, for example, the end effector  200  may be closed and remain in that state). Otherwise, the pulling of the opening/closing wire  800  may be released (thus, for example, the end effector  200  may be opened). 
       Second Embodiment 
       [0061]    According to the present embodiment, there is provided a minimally invasive surgical instrument comprising a handling unit  400 ′ having a configuration slightly different from that of the handling unit  400  according to the first embodiment of the invention. 
         [0062]      FIG. 11  shows the handling unit  400 ′ of the minimally invasive surgical instrument according to another embodiment (a second embodiment) of the invention. 
         [0063]    Reference will be made to  FIG. 11 . The handling unit  400 ′ may be roughly divided into a first section  430 ′ and a second section  440 ′. The first and second sections  430 ′ and  440 ′ may preferably be configured to separate from each other. According to this configuration, if the first section  430 ′ is damaged, for example, then only the first section  430 ′ may be replaced by a new one. The components included in the first and second sections  430 ′ and  440 ′ of the handling unit  400 ′ will be described later. 
         [0064]    Further, the handling unit  400 ′ may comprise a guide  460 ′. The guide  460 ′ may be configured in the form of a cone, hemisphere or pyramid, or in the form similar to one or more of the foregoing, so that a pitch wire (not shown) and/or a yaw wire (not shown) from a sliding block to be described below and/or an opening/closing wire (not shown) and/or torque transmission member to be described below may be guided to the cavity of the shaft  100 . As described above, the above wires or torque transmission member may act on the joint unit  300  or the end effector  200  to cause the joint motion, rolling motion, opening/closing motion and the like of the end effector  200 . 
         [0065]      FIG. 12  shows the first section  430 ′ of the handling unit  400 ′, and  FIG. 13  shows the (internal) components of the first section  430 ′ shown in  FIG. 12 . 
         [0066]    Reference will be made to  FIGS. 12 and 13 . There may be formed in the first section  430 ′ (preferably a plurality of) wire through-holes  431 ′. In addition, a wire A and/or wire B may be further arranged. The wire A and/or wire B may be disposed through the wire through-holes  431 ′. On the one hand, the wires A, B may be connected to at least one (preferably two different) electric motors (not shown), respectively. On the other hand, they may be connected to a first rotating member  435 ′ or a second rotating member  436 ′, respectively, to rotate the first or second rotating member  435 ′ or  436 ′ by means of the power of the electric motors, thereby causing the pitch direction or yaw direction operation of the end effector  200 . Meanwhile, a rolling wire (not shown) may be further disposed through the through-holes  431 ′ if necessary. The rolling wire may be connected to (another) electric motor on the one hand and connected to a third rotating member  437 ′ on the other hand to rotate the third rotating member  437 ′ by means of the power of the electric motor, thereby causing the roll direction operation of the end effector  200 . 
         [0067]    As shown, the wire A may be connected to the first rotating member  435 ′ via a first set of pulleys  432 ′ (e.g., a pair of pulleys  432   a ′ and  432   b ′). When the wire A transmits rotation from the electric motor to the first rotating member  435 ′, the first set of pulleys  432 ′ may serve to change the rotation axis thereof. Further, the first rotating member  435 ′ may comprise an insert  435   a ′. The insert  435   a ′ may be inserted and fixed to a first linear motion converting member to facilitate the rotation of the first linear motion converting member according to the rotation of the first rotating member  435 ′. Meanwhile, the wire A may be led into and wound within the first rotating member  435 ′ as shown, but may also be otherwise configured. 
         [0068]    In the same manner, the wire B and the rolling wire may be connected to the second or third rotating member  436 ′ or  437 ′ via a second or third set of pulleys  433 ′ or  434 ′, respectively. In the above case, the second or third rotating member  436 ′ or  437 ′ may be configured similarly to the first rotating member  435 ′, and the second or third set of pulleys  433 ′ or  434 ′ may also be configured similarly to the first set of pulleys  432 ′. 
         [0069]      FIG. 14  shows the (internal) components of the second section  440 ′ of the handling unit  400 ′, and  FIG. 15  shows some components thereof. 
         [0070]    Further reference will be made to  FIGS. 14 and 15 . The second section  440 ′ may include a first linear motion converting member  441 ′ therein. The first linear motion converting member  441 ′ may include a recess  441   a ′ in which the insert  435   a ′ of the first rotating member  435 ′ may be inserted to receive rotation from the first rotating member  435 ′. Further, the first linear motion converting member  441 ′ may include a screw thread (not shown) on a part of the surface thereof. The first linear motion converting member  441 ′ may be fixed to some part in the second section  440 ′ so that it may not carry out forward and backward motion other than rotational motion around the longitudinal axis thereof as the rotation axis. Meanwhile, the second section  440 ′ may further comprise a first sliding block  444 ′ that may carry out linear motion. The first sliding block  444 ′ may include a screw groove (not shown) in a through-hole (not shown) therein. Thus, when the first linear motion converting member  441 ′ fixed to some part in the second section  440 ′ rotates according to the rotation of the first rotating member  435 ′, the first sliding block  444 ′ with the first liner motion converting member  441 ′ being inserted in the corresponding through-hole may carry out linear motion in forward or backward direction. 
         [0071]    As the first sliding block  444 ′ carries out the linear motion, a first rack element  444   a ′ that may be formed on the first sliding block  444 ′ may also carry out linear motion together. This may cause the rotation of a pinion gear  449 ′ that may be arranged engaging with the first rack element  444   a ′ as shown. Then, this may lead to the linear motion of a second rack element  445   a ′ that may be disposed opposite to the first rack element  444   a ′ across the pinion gear  449 ′. Therefore, the first and second rack elements  444   a ′ and  445   a ′ may carry out linear motion in the opposite directions and at substantially the same distance with respect to each other. Accordingly, a second sliding block  445 ′, which may also be included in the second section  440 ′ and comprise the second rack element  445   a ′, may also carry out linear motion in the opposite direction and at substantially the same distance with respect to the linear motion of the first sliding block  444 ′. 
         [0072]    Meanwhile, the second section  440 ′ may further include therein a second linear motion converting member  442 ′, a third sliding block  446 ′ and a fourth sliding block  447 ′. The configurations and operating principles of these components may be similar to those of the above-described components. 
         [0073]    Further, the second section  440 ′ may further include therein a first gear  443 ′ and a second gear  448 ′. The first gear  443 ′ may include a recess  443   a ′ in which an insert (not shown) of the third rotating member  43 T may be inserted to receive rotation from the third rotating member  437 ′. The first gear  443 ′ may engage with the second gear  448 ′. The second gear  448 ′ may be connected to or integrated with the torque transmission member. Therefore, when the first gear  443 ′ rotates according to the rotation of the third rotating member  437 ′, the second gear  448 ′ rotates to eventually cause the rolling motion of the end effector  200 ′. Meanwhile, an opening/closing wire through-hole  448   a ′ may be formed in the second gear  448 ′. Thus, the opening/closing wire may be disposed in the handling unit  400 ′. 
         [0074]      FIG. 16  shows the operation of the handling unit  400 ′ of the minimally invasive surgical instrument according to another embodiment of the invention. 
         [0075]    Further reference will be made to  FIG. 16 . As described above, when the wire A transmits rotation from the electric motor to the first rotating member  435 ′, this may eventually cause the first and second sliding blocks  444 ′ and  445 ′ to carry out linear motion in the opposite directions. In this case, each of the first and second sliding blocks  444 ′ and  445 ′ may carry out forward and backward motion in the opposite directions and at substantially the same distance with respect to each other while grasping the pitch wire (or yaw wire). The pitch wire (or yaw wire) may be guided to the cavity of the shaft  100  along the guide  460 ′ and connected to the joint unit  300 . Therefore, the first and second sliding blocks  444 ′ and  445 ′ may control the joint unit  300  to cause the pitch direction (or yaw direction) operation of the end effector  200 . In the same manner, each of the third and fourth sliding blocks  446 ′ and  447 ′ may carry out forward and backward motion in the opposite directions and at substantially the same distance with respect to each other while grasping the yaw wire (or pitch wire). Therefore, the third and fourth sliding blocks  446 ′ and  447 ′ may cause the yaw direction (or pitch direction) operation of the end effector  200 . In connection with the principle thereof, further reference may be made to those disclosed in the aforementioned Korean patent applications, particularly Korean Patent Application No. 2010-115152. 
       APPLICATIONS 
       [0076]    According to an application of the present invention, the minimally invasive surgical instrument may be connected with a driving element (e.g., the external driving element  900 ) of another motor-based system (not shown) such as a surgical robot as necessary, so that the end effector  200  may carry out joint motion without requiring the action of the internal driving elements. To this end, the form and the like of the handling unit  400 ,  400 ′ may be partially modified to be suitable for the connection to another motor-based system. Further, the form and the like of the handling unit  400 ,  400 ′ may be partially modified to enable the end effector  200  to carry out rolling motion or opening/closing motion by means of another motor-based system as necessary. 
         [0077]    Although the present invention has been described in terms of specific items such as detailed elements as well as the limited embodiments and the drawings, they are only provided to help general understanding of the invention, and the present invention is not limited to the above embodiments. It will be appreciated by a person of ordinary skill in the art that various modifications and changes may be made from the above description. 
         [0078]    Therefore, the spirit of the present invention shall not be limited to the above-described embodiments, and the entire scope of the appended claims and their equivalents will fall within the scope and spirit of the invention.