Patent Publication Number: US-2005137613-A1

Title: Operating trocar

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
      This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2001-401943, filed Dec. 28, 2001, the entire contents of the application are incorporated herein by reference.  
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a trocar for introducing an endoscope, a therapeutic instrument and the like into a living body during operation. A trocar according to the invention is suited to, for example, endoscopic surgical operation.  
      2. Description of the Related Art  
      Various types of trocars for introducing endoscopes, therapeutic instruments and the like into living bodies are known.  
      Japanese Utility Model Registration No. 3024069 discloses an art of providing a balloon-like stopper on a trocar to prevent the trocar from coming off.  
      Japanese Patent Laid-Open No. 28666/1997 discloses an art of preventing a trocar from coming off, by expanding an expanding portion in a body cavity.  
     BRIEF SUMMARY OF THE INVENTION  
      A trocar according to the invention includes a guide tube for introducing a medical instrument into a living body and a flange provided on an outer circumference of the guide tube at a location other than opposite ends thereof, the flange having a surface which comes into contact with an outer surface of the living body and which is oblique with respect to an axis of the guide tube.  
      In addition, it is preferable that at least a part of the trocar be formed of an elastic material so that the trocar can follow the movement of the medical instrument.  
      In the trocar, it is general to integrate the guide tube and the flange, but the guide tube and the flange may also be constructed to be removably secured to each other so that the trocar can be conveniently cleaned and stored. In addition, this construction makes it easy to manufacture trocars.  
      In addition, in order to increase the adhesion between the flange and the outer surface of the living body, it is preferable to provide a fixing portion (for example, an adhesive layer provided on the surface of the flange which comes into contact with the outer surface of the living body, an adhesive sheet wider in area than the flange and stuck to the surface of the flange opposite to the surface which comes into contact with the outer surface of the living body, or a fixing band extending from the flange). Holes through which to pass sutures may also be provided in the flange in order to fix the trocar to the living body.  
      In the guide tube, a gastightness retaining member (for example, an O-ring or a valve) may also be provided so that the gastightness of a body cavity can be efficiently retained.  
      It is preferable that the wall thickness of the guide tube be made a thickness suited for the insertion of the guide tube and the wall thickness of the flange be made a thickness which enables the flange to easily adhere to the body surface. Accordingly, in general, both wall thicknesses differ from each other, and in many cases, the flange is thinner in wall thickness than the guide tube.  
      Some of the above-described additional features of the invention can also be applied to known trocars. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
      These and other features, aspects, and advantages of the apparatus and methods of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings where:  
       FIG. 1  is an exploded side view of a blood vessel harvester including a trocar according to a first embodiment of the invention;  
       FIG. 2A  is a perspective view of the trocar according to the first embodiment, and  FIG. 2B  is a longitudinal sectional view of the same trocar;  
       FIG. 3  is a view showing the state in which a dissected portion of skin is formed in a lower limb according to the first embodiment;  
       FIG. 4  is a cross-sectional view showing the state in which the trocar according to the first embodiment is fitted into the dissection portion of skin of the lower limb and a dissector is inserted into a cavity by using the trocar as a guide;  
       FIG. 5  is a general construction diagram showing the state in which a therapeutic sheath is inserted into the cavity by using the trocar in the first embodiment as a guide  FIG. 6  is a perspective view of a trocar according to a second embodiment of the invention;  
       FIG. 7  is a cross-sectional view showing the manner in which the trocar shown in  FIG. 6  is used  
       FIG. 8  is a perspective view of a trocar according to a third embodiment of the invention  
       FIG. 9  is a cross-sectional view showing the manner in which the trocar shown in  FIG. 8  is used;  
       FIG. 10  is a perspective view of a trocar according to a fourth embodiment of the invention  
       FIG. 11  is a cross-sectional view showing the manner in which the trocar shown in  FIG. 10  is used  
       FIG. 12  is a perspective view of a trocar according to a fifth embodiment of the invention;  
       FIG. 13  is a cross-sectional view showing the manner in which the trocar shown in  FIG. 12  is used;  
       FIG. 14  is a perspective view of a trocar according to a sixth embodiment of the invention  
       FIGS. 15A  to  15 C are perspective views showing a plurality of trocars which differ in the inclination angles of their guide tubes to their flanges;  
       FIG. 16  is a perspective view showing the manner in which the trocars shown in  FIGS. 15A  to  15 C are used;  
       FIG. 17  is a perspective view showing the manner in which the trocars shown in  FIGS. 15A  to  15 C are used; and  
       FIG. 18A  is a perspective view of a trocar according to a seventh embodiment of the invention, and  FIG. 18B  is a cross-sectional view of the trocar shown in  FIG. 18A . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      Preferred embodiments of the invention will be described below with reference to the accompanying drawings.  
       FIG. 1  shows an endoscopic blood vessel harvester including a trocar for endoscopic operation according to a first embodiment of the invention. As shown, the endoscopic blood vessel harvester is made of a trocar  1 , a therapeutic sheath  2 , a dissector  3  which serves as expanding means, and a rigid scope  4  which serves as an endoscope.  
      As shown in  FIGS. 2A and 2B , the trocar  1  comprises a flange  5  which has an approximately disk-like shape and is provided with a cylindrical guide tube  6  in such a manner that the guide tube  6  is obliquely inserted through the flange  5 . In many cases, trocars are integrally molded from a synthetic resin material (for example, polysulfone), or formed of a metal (for example, SUS 304 stainless steel). In the first embodiment, the trocar  1  is formed of an elastic material (for example, silicone rubber) so that the trocar  1  has elasticity. As a matter of course, when the trocar  1  is to be given elasticity, the whole of the trocar  1  need not be formed of an elastic material, and only the necessary part of the trocar  1  may be formed of an elastic material. In many cases, the portions of guide tubes that are to be inserted into the bodies of patients do not need great elasticity, but flange portions which come into contact with the body surfaces of patients need great elasticity. In view of this situation, an elastic material can also be used mainly for the flange portions.  
      The outer surface of the guide tube  6  is covered with a lubricating coating for improving the smoothness of insertion of the guide tube  6 . A tip  6   a  of this guide tube  6  is cut at an acute angle, and the end surface of the tip  6   a  is formed approximately in parallel with the flange  5 .  
      In addition, the inner circumferential surface of the proximal end of the guide tube  6  is integrally provided with a gastight ring portion  7  which serves as a gastightness retaining member (a sealing member), and an intermediate portion of the guide tube  6  is integrally provided with a gas feed connecting portion  8 . The gastightness retaining member is provided on a side closer to the proximal end than the gas feed connecting portion  8  (on a side far from the interior of a patient). This construction aims to prevent a gas fed into the trocar  1  through the gas feed connecting portion  8  from leaking out of the trocar  1  at the proximal end. In addition, the bottom or contact surface of the flange  5   a  (the surface of the flange  5  which comes into contact with the patient) is provided with an adhesive layer  9  (for example, adhesive tape) so that the trocar  1  can be adhesively fixed to the skin of the patient.  
      As shown in  FIG. 1 , the therapeutic sheath  2  has a sheath body  10 . The sheath body  10  has the form of a straight cylinder made of a synthetic resin material or the like, and the outer surface of the sheath body  10  is covered with a lubricating coating for improving the smoothness of insertion of the sheath body  10 . The sheath body  10  is constructed so that a rigid scope  4  can be freely inserted into and extracted from the interior of the sheath body  10 . In addition, the sheath body  10  is provided with a first therapeutic instrument channel and a second therapeutic instrument channel. A bipolar cutter  18  is inserted through the first therapeutic instrument channel as a high-frequency therapeutic instrument. The bipolar cutter  18  is constructed to move axially back and forth when a therapeutic instrument manipulating portion  19  is slid axially back and forth. In addition, a blood vessel holder  21  is inserted through the second therapeutic instrument channel, and is constructed to move axially back and forth when a holder manipulating portion  22  is slid axially back and forth.  
      The dissector  3  has a straight cylindrical inserting tube  36 , as shown in  FIG. 1 . An axial portion of this inserting tube  36  is provided with an inserting passage through which to insert an inserting portion  35  of the rigid scope  4 . The outer surface of the inserting tube  36  is covered with a lubricating coating for improving the smoothness of insertion of the inserting tube  36 . A dissecting portion  38  made of a transparent synthetic resin material formed into a conical shape is fixed to the distal end of the inserting tube  36 .  
      The rigid scope  4  has the inserting portion  35  and an eyepiece portion  31 , and a light guide connecting portion  33  is provided on the side of the rigid scope  4 .  
      A case where the blood vessel harvester constructed in the above-described manner is used to extract an extraction target blood vessel (hereinafter referred to simply as a blood vessel) along the full length thereof will be described below with illustrative reference to a great saphenous vein which extends from the inguinal region of the thigh to the ankle of either of the lower limbs.  
       FIG. 3  shows a lower limb  60 , and reference numeral  61  denotes a blood vessel. A dissected portion of skin  64  is provided between a knee  62  and an inguinal region  63 . As shown, when an operator is to extract the blood vessel  61  between the knee  62  and the inguinal region  63 , the operator provides the dissected portion of skin  64  at one location of the knee  62  immediately above the blood vessel  61  by means of a scalpel or the like.  
      Then, the operator exposes the blood vessel  61  in the dissected portion of skin  64  by means of the dissector  3  or the like. Further, the operator dissects tissues immediately above the blood vessel  61  by means of the similar dissector  3  or the like over a distance from the dissected portion of skin  64 , which distance is observable with the naked eyes.  
       FIG. 5  shows the manner in which the therapeutic sheath  2  having the rigid scope  4  inserted inside is inserted through the trocar  1 . In the combination shown in  FIG. 5 , the dissector  3  may also be substituted for the therapeutic sheath  2 . In this substituted combination, the operator proceeds dissection with the dissector  3 . An image of the status of dissection through the dissecting portion  38  of the dissector  3  is picked up by a TV camera  75  via a TV camera head  74  connected to the eyepiece portion  31  of the rigid scope  4 , and the picked-up image is displayed on a monitor  76  as a monitor image.  
      Then, as shown in  FIG. 4 , the operator inserts the dissecting portion  38  along the blood vessel  61 , and when the dissecting portion  38  is inserted to a small extent, the operator inserts the guide tube  6  of the trocar  1  toward the inguinal region  63  obliquely (approximately in parallel with the blood vessel  61 ). When the tip  6   a  of the trocar  1  is turned downward, the adhesive layer  9  on the bottom surface  5   a  of the flange  5  is adhesively fixed to skin  65 . In this state, the operator connects a gas feed tube  67  connected to a gas feed pump  66  to the gas feed connecting portion  8 .  
      In this case, since the outer circumferential surface  6   f  the inserting tube  36  of the dissector  3  adheres closely to the gastight ring portion  7 , the interior of the guide tube  6  and the interior of a cavity  69  is placed in a gastight state, and a gas feed passage  68  is established in an annular space between an inner surface of the guide tube  6  and the outer circumferential surface of the inserting tube  36 .  
      The light guide connecting portion  33  of the rigid scope  4  is connected to a light source device  78  via a light guide cable  57 . Accordingly, illuminating light can be projected from a tip portion of the rigid scope  4  to illuminate the interior of the cavity  69 . When the gas feed pump  66  is driven, a gas is fed into the cavity  69  via the gas feed tube  67 , the gas feed connecting portion  8  and the gas feed passage  68 , whereby the cavity  69  is expanded.  
      At this time, in the cavity  69 , a subcutaneous tissue  70  and a connective tissue of blood vessel  71  lie under the skin  65 , and a blood vessel  61  exists under the connective tissue of blood vessel  71 . The blood vessel  61  has a plurality of side branches  72 , and the branch ends of the respective side branches  72  are connected to the connective tissue of blood vessel  71 . Subcutaneous fat  73  adheres to the connective tissue of blood vessel  71 .  
      Subsequently, the operator inserts the dissect or 3 more deeply in the expanded cavity  69  while guiding the dissector  3  by means of the guide tube  6 . At this time, since the guide tube  6  is formed to extend obliquely with respect to the flange  5 , the guide tube  6  can guide the dissector  3  obliquely with respect to the body surface, thereby successfully introducing the dissector  3  along the running direction of the blood vessel  61 .  
      During the insertion of the dissector  3 , while the operator is observing the cavity  69  on the monitor  76  to take care not to injure the blood vessel  61  nor the side branches  72 , the operator gradually advances the dissector  3  by repeating the manipulation of pushing the dissector  3  to a small extent to dissect the connective tissue of blood vessel  71  from the blood vessel  61  and the side branches  72  by means of the dissecting portion  38  and then pull ng the dissector  3  to a small extent. During this time, even if the dissector  3  is oscillated vertically and horizontally, the trocar  1  does not at all come off the skin  65 , because the trocar  1  is fixed to the skin  65  by the adhesive layer  9 . In addition, since the trocar  1  (the guide tube  6  and the flange  5 ) is formed of an elastic material, the trocar  1  can smoothly follow the movement of the dissector  3  owing to its elastic deformation (the trocar  1  can absorb the deformation of the body surface due to the movement of the dissector  3 ).  
      After the operator has inserted the dissector  3  along the blood vessel  61  from the knee  62  toward the inguinal region  63  and completed a dissecting operation with the dissector  3  in the above-described manner, the operator extracts the dissector  3  from the trocar  1 . Then, as shown in  FIG. 5 , the operator inserts the therapeutic sheath  2  in which the rigid scope  4  is inserted, into the guide tube  6  of the trocar  1 . At this time as well, the guide tube  6  which is formed to extend obliquely with respect to the flange  5  can guide the therapeutic sheath  2  obliquely with respect to the body surface, thereby successfully introducing the therapeutic sheath  2  along the running direction of the blood vessel  61 .  
      When the operator grips the therapeutic sheath  2  in one hand and advances the holder manipulating portion  22  by using, for example, the thumb of the one hand, the blood vessel holder  21  projects from the tip of the sheath body  10 . In addition, when the operator advances the therapeutic instrument manipulating portion  19  by using the index finger of the one hand in which the therapeutic sheath  2  is gripped, the bipolar cutter  18  projects from the tip of the sheath body  10 . Namely, the operator can move the blood vessel holder  21  and the bipolar cutter  18  back and forth while gripping the sheath body  10  in only one hand. Accordingly, the operator can easily sever the side branches  72  by means of the bipolar cutter  18  while holding the blood vessel  61  to be extracted, by means of the blood vessel holder  21 . At this time as well, the trocar  1  (the guide tube  6  and the flange  5 ) which is formed of an elastic material can smoothly follow the movement of the therapeutic sheath  2  owing to its elastic deformation.  
      The operator repeats the operation of severing each of the side branches  72  to dissect the blood vessel  61  from the connective tissue of blood vessel  71 , and when the operation advances up to the inguinal region  63 , the operator completes severing the side branches  72 . Then, the operator forms a small dissected portion of skin in the inguinal region  63  immediately above the blood vessel  61  by means of a scalpel or the like, and draws out the blood vessel  61  through this dissected portion of skin  64 . The operator can sever the drawn portion of the blood vessel  61 , and ligates both severed ends of the blood vessel  61  with a suture. Then, the operator performs the operation of extracting the portion of the blood vessel  61  that extends from the dissected portion of skin  64  of the knee  62  toward the ankle of the lower limb  60 , thereby finally extracting a single blood vessel (about 60 cm long). The method of manipulation is basically the same as the above-described method of harvesting the portion of the blood vessel  61  that extends from the knee  62  to the inguinal region  63 , and detailed explanation is omitted. The vessel which is cut its both sides is removed from the dissected portion of skin  64 .  
      As described above, the trocar  1  according to the first embodiment is provided with the flange  5  which is to be adhesively fixed to the body surface. Accordingly, the trocar  1  does not need to have a complicated stopper structure such as a balloon or an expanding portion, and makes it possible to prevent the guide tube  6  from coming off, merely by adhesively fixing the flange  5  to the body surface. Namely, the trocar  1  according to the first embodiment is inexpensive in that the guide tube  6  can be effectively prevented from coming off, by means of a simple construction.  
      In addition, in the trocar  1  according to the first embodiment, the flange  5  is provided on the guide tube  6  so as to make a predetermined angle (except zero degrees) with a plane approximately perpendicular to the axial direction of the guide tube  6 . In other words, the guide tube  6  extends through the flange  5  obliquely with respect to the extending direction of the flange  5 . Accordingly, the guide tube  6  can guide an endoscope, a therapeutic instrument and the like obliquely with respect to the body surface. Therefore, the operator can make observations in various directions through an endoscope inserted through the guide tube  6 , and can also guide an endoscope and a therapeutic instrument in various directions as occasion demands. Particularly in the case of the first embodiment used for the extraction of a blood vessel, the dissector  3  can be guided obliquely with respect to the body surface, thereby successfully introducing the dissector  3  along the running direction of the blood vessel  61 .  
      In addition, since the flange  5  is provided on the outer circumference of the guide tube  6  at a location other than the opposite ends thereof, a part of the guide tube  6  is exposed outside the body of the patient when the trocar  1  is inserted in the patient. Accordingly, the operator can easily grip the trocar  1  with good operability.  
      The trocar  1  according to the first embodiment is provided with, in addition to the stopper structure (the flange  5 ), the gastightness retaining member (sealing member)  7  which retains the gastightness of the gap between the circumferential surface of the internal hole of the guide tube  6  and an outer surface of an endoscope or a therapeutic instrument inserted in the internal hole (or conduit) of the guide tube  6 . Accordingly, the trocar  1  can reliably retain the gastightness of a body cavity, this feature is particularly important for endoscopic surgical operation.  
      In addition, since the trocar  1  according to the first embodiment is formed of an elastic material, the whole of the trocar  1  can smoothly follow the movement of the dissect or  3  owing to its elastic deformation (the trocar  1  can absorb the deformation of the body surface due to the movement of the dissector  3 ).  
      Furthermore, since the trocar  1  is formed of an elastic material, the angle made by the flange  5  with the axis of the guide tube  6  is variable within an elastically allowable range. Accordingly, when the trocar  1  is inserted in the patient, the flange  5  can easily adhere to the body surface of the patient. As a matter of course, the angle made by the flange  5  with the axis of the guide tube  6  can also be made variable by using a mechanical joint (for example, the guide tube  6  is inserted through a spherical member and a flange having a center opening which diameter is smaller than the diameter of the spherical member and larger than the diameter of the guide tube  6  is fitted onto the guide tube  6  as the flange  5 ).  
      Incidentally, in the first embodiment, the whole of the trocar  1  is formed of an elastic material, but at least one of the flange  5  and the guide tube  6  or at least a part of the flange  5  or at least a part of the guide tube  6  may be formed of an elastic material. Means for fixing the flange to the body surface is not limited to adhesion, and any fixing means that can easily fix the flange  5  to the body surface may be used. In addition, the gastightness retaining member (sealing member)  7  need not be an O-ring such as that used in the first embodiment, and may have any construction that can retain the gastightness of the body cavity.  
      FIGS.  6  to  18  show other embodiments of the invention (a second embodiment to a seventh embodiment). In these embodiments, constituent portions common to the first embodiment are denoted by the same reference numerals as those used in the first embodiment, and the description of the same constituent portions is omitted.  
       FIGS. 6 and 7  show a trocar  1 A according to the second embodiment of the invention. The trocar  1 A according to the second embodiment does not have the adhesive layer  9  provided on the bottom surface  5   a  of the flange  5 . Instead, an adhesive seal  100  having an adhesive layer  10   a  is stuck to the flange  5 , and as shown in  FIG. 7 , the flange  5  is fixed to the body surfaces  65  and  70  by using the adhesive seal  100 . Incidentally, the constructions of the other portions are the same as those in the first embodiment.  
      According to the construction of the second embodiment, since the adhesive layer  9  is not provided, it is possible to produce the trocar  1 A itself more easily, and as long as the adhesive seal  100  has elasticity, the trocar  1 A can follow the movement of an endoscope and a therapeutic instrument to some extent even if neither the flange  5  nor the guide tube  6  has elasticity. For example, the seal  100  is a polyurethane film on one side of which hypoallergenic acrylic adhesive is applied. In this case, the seal  100  has elasticity since polyurethane is used as a base material.  
       FIGS. 8 and 9  show a trocar  1 B according to the third embodiment of the invention. As shown in  FIG. 8 , the trocar  1 B according to the third embodiment is constructed so that the flange  5  and the guide tube  6  can be separated from each other. Specifically, a fixed ring  105  is provided on the inner circumference of the ring-shaped flange  5 , and an engaging groove  6   b  which engages with the fixed ring  105  is formed on the outer circumferential surface of the guide tube  6 . The engaging groove  6   b  obliquely extends to make a predetermined angle with a plane perpendicular to the direction of the longitudinal axis of the guide tube  6 , and the engaging groove  6   b  is arranged to direct the guide tube  6  obliquely with respect to the extending direction of the flange  5  when the engaging groove  6   b  engages with the fixed ring  105  (the flange  5  is arranged to be directed by the engaging groove  6   b  so that the flange  5  makes a predetermined angle with a plane approximately perpendicular to the axial direction of the guide tube  6 ). In addition, since the engagement is so tight, a seal capable of fully retaining the gastightness of a body cavity is formed when the engaging groove  6   b  and the fixed ring  105  are engaged with each other. Incidentally, the constructions of the other portions are the same as those in the first embodiment. The flange  5  and fixed ring  105  are elastomers or a soft thermoplastic which can be plastically deformed to stretch over the guide tube. When the flange  5  is fixed to the guide tube  6 , the flange  5  and fixed ring  105  are extended until the fixed ring  105  corresponds with the groove  6   b , at which point, the flange is relaxed and the fixed ring  105  engages with the groove  6   b.    
       FIG. 9  shows the state in which the guide tube  6  which is fitted in the flange  5  is fixed to the body surface s  65  and  70 . As shown, the guide tube  6  extends obliquely with respect to the body surfaces  65  and  70 , whereby the third embodiment can serve effects and advantages similar to those of the first embodiment.  
      According to the third embodiment, since the guide tube  6  and the flange  5  can be separated in the above-described manner, the trocar  1 B is superior in ease of cleaning and ease of storage, and is also easy to manufacture. In addition, the trocar  1 B is useful in that the flange  5  and the guide tube  6  can be formed of different materials. In addition, the engaging portion of the guide tube  6  may use spaced projections (not shown) instead of the engaging groove  6   b  where the fixed ring  105  is captured between the spaced projections.  
       FIGS. 10 and 11  show a trocar  1 C according to the fourth embodiment of the invention. As shown in  FIG. 10 , the trocar  1 C according to the fourth embodiment does not have the adhesive layer  9  provided on the bottom surface of the flange  5 . Instead, a plurality of holes  110  for tying sutures are formed in the flange  5 . Incidentally, the constructions of the other portions are the same as those in the first embodiment.  
      According to the construction of the fourth embodiment, as shown in  FIG. 11  by way of example, after a needle (not shown) with a suture  112  has been stuck into the body surface s  65  and  70 , the needle is passed through one of the holes  110  of the flange  5  and both ends of the suture  112  are tied together, whereby the flange  5  can be fixed to the body surfaces  65  and  70  by the sutures  112 .  
       FIGS. 12 and 13  show a trocar  1 D according to the fifth embodiment of the invention. As shown in  FIG. 12 , the trocar  1 D according to the fifth embodiment has a construction in which a band  129  extending from the flange  5  has a Hook-and-Loop fastener (for example, Velcro® fastener)  121  whose fastening halves are respectively provided at the opposite ends of the band  129 . Namely, the flange  5  and the band  129  form a fixing belt  120  for fixing the guide tube  6  to a living body. Incidentally, the constructions of the other portions are the same as those in the first embodiment. The band  129  is made of elastomer or soft thermoplastic, and is attached to the guide tube  6  like flange  5  in the third embodiment.  
      According to the construction of the fifth embodiment, as shown in  FIG. 13 , it is possible to prevent the guide tube  6  from coming off, by winding the fixing belt  120  around, for example, the knee  62  of the lower limb  60 .  
      Accordingly, since the trocar  1 D according to the fifth embodiment has belt-like stopper means, the trocar  1 D can be reliably fixed, and is particularly suited to an arm, a leg and the like.  
       FIG. 14  shows a trocar  1 E according to the sixth embodiment. In the trocar  1 E according to the sixth embodiment, the gastightness retaining member (sealing member) provided in the guide tube  6  is formed as a valve  7 A. Specifically, a tubular support portion  125  which supports a valve flap  151  in a turnable manner extends to project into the guide tube  6  from the operator side of the guide tube  6 , and a member (for example, an elastic body)  150  which comes into pressure contact with the outer circumferential surface of an endoscope or a therapeutic instrument to be inserted into the guide tube  6  is fitted to the external end of the support portion  125 . Incidentally, the valve flap  151  can open and close the passage of the guide tube  6  by turning about a pivot  127  provided in the support portion  125 . In addition, the valve flap  151  is biased in the closing direction by a spring  152 . The constructions of the other portions are the same as those in the first embodiment.  
      According to the construction of the sixth embodiment, when an endoscope or a therapeutic instrument is inserted into the support portion  125  to press the valve flap  151 , the valve flap  151  is turned and opened against the urging force of the spring  152 , whereby the endoscope or the therapeutic instrument can be inserted through the guide tube  6 . In this case, since the elastic body  150  comes into pressure contact with the outer circumferential surface of the endoscope or the therapeutic instrument, the gastightness of the body cavity can be retained. In addition, even after the endoscope or the therapeutic instrument has been removed from the guide tube  6 , the gastightness of the body cavity can still be retained, because the valve flap  151  is closed by the biasing force of the spring  152 .  
       FIGS. 15A  to  15 C respectively show a plurality of trocars  1 F,  1 G and  1 H which differ in the inclination angle of the guide tube  6  to the flange  5 . These trocars  1 F,  1 G and  1 H are used for introducing a plurality of operating instruments  130 ,  2 , and  132 , respectively, into the body of a patient, and the operating instruments  130 ,  2 , and  132  differ in access direction relative to a therapeutic target part (affected part) O (hence, in inclination angle relative to the body surface) as shown in  FIG. 16 . The therapeutic target part O to be accessed may be an organ inside an abdominal wall  140  as shown in  FIG. 17 , or may also be the blood vessel  61  inside the lower limb  60  as described previously. Accordingly, the kind of area to which the trocar according to the invention can be applied is not at all be limited.  
       FIGS. 18A and 18B  show a trocar  1 I according to the seventh embodiment of the invention. As clearly shown in  FIG. 18A , in the trocar  1 I according to the seventh embodiment, a wall thickness t 2  of the flange  5  is set to be thinner than a wall thickness t 1  of the guide tube  6 . Incidentally, the constructions of the other portions are the same as those in the first embodiment.  
      Incidentally, in the case where the wall thickness of the flange  5  is not constant or the wall thickness of the guide tube  6  is not constant, the wall thickness of the guide tube  6  may be determined from the average wall thickness of the portion of the guide tube  6  that is to be inserted into a living body, while the wall thickness of the flange  5  may be determined from the average wall thickness of the portion of the flange  5  that is to come into contact with a living body.  
      According to the construction of the seventh embodiment, the guide tube  6  can be easily inserted into a dissected portion of skin, and the flange  5  can be easily made to adhere to the skin.  
      While there has been shown and described what is considered to be preferred embodiments of the invention, it will, of course, be understood that various modifications and changes in form or detail could readily be made without departing from the spirit of the invention. It is therefore intended that the invention be not limited to the exact forms described and illustrated, but should be constructed to cover all modifications that may fall within the scope of the appended claims.