Patent Publication Number: US-2022211978-A1

Title: Holding mechanism assembly

Description:
TECHNICAL FIELD 
     The invention relates to a holding mechanism assembly. 
     BACKGROUND ART 
     A tubular body (for example, a medical tube), which is to be inserted through the living body and communicates the inside and the outside of the living body, is held to the living body by a holding mechanism assembly for holding the tubular body to an insertion target. (see Patent document 1, for example). The holding mechanism assembly of Patent document 1 comprises: a driveline being a medical tube; a fixing device having an inserting portion into which the driveline is inserted; and a holding structure being provided in the inserting portion to hold the driveline in a liquidtight manner. The driveline is inserted into the holding structure provided in the inserting portion passing through the fixing device and is held by the fixing device. To fix the driveline to the living body, the fixing device is fixed to the incised area of the skin of the living body. 
     The holding structure provided in the inserting portion of the fixing device of Patent document 1 is provided in a part of the inserting portion in the axial direction of the inserting portion, not provided across the entirety in the axial direction of the inserting portion. Thus, a space is formed, in the radial direction of the driveline, between the inner surface of the inserting portion and the outer surface of the driveline extending by passing through the holding structure. When a predetermined time period elapses after the fixing device is fixed to the skin, cells surrounding the site to which the fixing device is fixed reproduce, so that the space formed between the inner surface of the inserting portion and the outer surface of the driveline is filled up with the reproduced cells. 
     PRIOR ART DOCUMENT 
     Patent Document 
     
         
         Patent Document 1: JP 2017-104437 A 
       
    
     SUMMARY OF THE INVENTION 
     Problem to be Solved by the Invention 
     However, in the above-described holding mechanism assembly, when the living body performs various actions after the holding mechanism assembly is attached to the living body, a relative movement between the driveline and the fixing device may occur. When such a relative movement occurs, cells invading into the above-mentioned space may be damaged to cause inflammation. In order to suppress such inflammation, predetermined measures against inflammation, for example, medication to suppress propagation of bacteria, needs to be taken. 
     An object of the invention is to provide a holding mechanism assembly that makes it possible to suppress cells being damaged in a space formed between an outer surface of a driveline and an inner wall of a communicating portion into which an inserting member is inserted. 
     Means to Solve the Problem 
     A holding mechanism assembly according to the invention comprises: a tubular inserting member, one end side of which is to be arranged in an inside of a living body and the other end side of which is to be arranged in an outside of the living body; a fixing device having a fixing portion to be fixed beneath a skin of the living body and a communicating portion into which the inserting member is inserted; and a holding structure provided in the communicating portion to hold the inserting member to the fixing device in a liquidtight manner, wherein the communicating portion has a first opening opened toward the outside of the living body when the fixing device is fixed beneath the skin; a second opening opened toward the inside of the living body when the fixing device is fixed beneath the skin; and a communication path formed between the first opening and the second opening; a space is formed, on the second opening side of the communication path with respect to the holding structure, between an inner wall of the communicating portion, which defines the communication path, and an outer surface of the inserting member; the outer surface of the inserting member has a covered region covered with fiber that can guide cells and a non-covered region not covered with the fiber; and the non-covered region of the inserting member extends between the holding structure and the second opening in the communication path. 
     Effects of the Invention 
     The holding mechanism assembly according to the invention makes it possible to suppress cells being damaged in a space formed between an outer surface of a driveline and an inner wall of a communicating portion into which an inserting member is inserted. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a lateral partial cross-sectional view of an overall configuration of a holding mechanism assembly according to one embodiment of the invention. 
         FIG. 2  shows an exploded perspective view of the holding mechanism assembly in  FIG. 1 . 
         FIG. 3  shows a partially enlarged cross sectional view of a holding structure of the holding mechanism assembly in  FIG. 1 . 
         FIG. 4  shows a top view of a fixing device according to one embodiment of the invention. 
         FIG. 5  is a schematic view showing the state of the living body at the time the holding mechanism assembly of  FIG. 1  is attached to the living body. 
         FIG. 6  is a schematic view showing the state in which the inserting member moves relatively with respect to the fixing device in a reference example in which fiber is provided on the outer surface, which opposes the inner wall of the communicating portion of the fixing device, of the inserting member. 
         FIG. 7  is a schematic view showing the state in which the inserting member moves relatively with respect to the fixing device, in the holding mechanism assembly of  FIG. 1 . 
     
    
    
     EMBODIMENT FOR CARRYING OUT THE INVENTION 
     Below, a fixing device according to one embodiment of the invention is explained with reference to the attached drawings. The embodiment shown below is merely one example, so that a fixing device in the invention is not limited to the embodiment below. 
     First, a holding mechanism assembly including a fixing device according to one embodiment of the invention will be explained. 
     The holding mechanism assembly is a structure for holding an inserting member to be inserted through an insertion target. Here, “insert” means that the inserting member having a predetermined length is at least in a state in which the inserting member is present across the interior and the exterior of the holding mechanism assembly. As long as the inserting member is inserted through the insertion target, the inserting member may pass through the insertion target or not pass through the insertion target. The insertion target has a hole through which the inserting member is to be inserted. The inserting member has a predetermined length. 
     For the inserting member, a flexible medical tube may be used as one example. In the embodiment, a driveline being one type of medical tube is used. The above-mentioned driveline is inserted from tissues outside the living body, such as the skin into inside the body, such as an organ. The inserting member is not limited to the driveline, so that the inserting member may be a catheter, a different medical tube, or a solid medical cable, or may be a different member having a predetermined length. 
     &lt;Configuration of Holding Mechanism Assembly&gt; 
     Next, the overall configuration of the holding mechanism assembly will be explained using  FIGS. 1 and 2 . 
     As shown in  FIG. 1 , a holding mechanism assembly  1  comprises: a tubular inserting member  2 , one end side of which is to be arranged in an inside of the living body and the other end side of which is to be arranged in an outside of the living body; a fixing device  3  having a fixing portion  31  to be fixed beneath the skin of the living body and a communicating portion  32  into which the inserting member  2  is inserted; and a holding structure  4  provided in the communicating portion  32  to hold the inserting member  2  to the fixing device  3  in a liquidtight manner. Here, the fixing device  3  is fixed to the skin S by anchoring (fixing) a part of the skin S to the surface of the fixing device  3 . 
     According to the embodiment, the inserting member  2  is a driveline as described above (below called a driveline  2 ). The driveline  2  is a tubular member. An end of the driveline  2  inside the body is coupled to a medical device (not shown) being arranged in the body. An end of the driveline  2  outside the body is coupled to a device (not shown) being arranged outside the body. A connector (not shown) for coupling a device (not shown) may be mounted to the end of the driveline  2  outside the body. The outer diameter of the connector may be greater or less than the outer diameter of the driveline  2 . 
     In the embodiment, the medical device arranged inside the body is an auxiliary artificial heart. The auxiliary artificial heart is a member having a pump to circulate blood in the body. The device arranged outside the body includes a pressure-feeding pump to send out cooling water to cool the above-mentioned pump and a power source to feed electric power to the pump. The driveline  2  has, in the interior thereof, a cooling water circulation path  21  to circulate cooling water between the pressure-feeding pump and the auxiliary artificial heart, and a power cable  22  to connect the power source and the pump. The configuration of the driveline  2  is not limited thereto, so that a publicly-known configuration may be adopted. For example, the driveline  2  may be configured to have only a power cable, may be configured to have only a cooling water circulation path, or may be configured to have a member having a different function. The driveline  2  includes the cooling water circulation path  21  containing water inside thereof and the power cable  22 , and is used as a medical tube having flexibility and rigidity. 
     The fixing device  3  has a fixing portion  31  to be fixed to the skin S and a communicating portion  32  through which the driveline  2  is inserted. A surface treatment is applied to at least a part of the fixing device  3  to promote anchoring of a part of the skin S. A material for the fixing device  3  is not particularly limited as long as the fixing device  3  has rigidity with which the fixing device  3  can be fixed to a target. In a case that the fixing device  3  is a member to be fixed to the skin S being biological tissues as in the embodiment, it is preferable that the fixing device  3  is formed of a metal having a high biocompatibility. Metals having the high biocompatibility include titanium and a titanium alloy, for example. The surface of the fixing portion  31  is formed with a porous material such as a mesh-shaped titanium fiber, into which porous material cells can invade, improving close contactability between the fixing portion  31  and the skin S to achieve the prevention of invasion of bacteria into the living body. 
     The fixing portion  31  of the fixing device  3  is fixed to the skin S by inducing the skin tissues of the incised skin S to the fixing portion  31 . In the embodiment, as shown in  FIGS. 1, 2, and 4 , the fixing portion  31  is extended from the communicating portion  32  outwardly in the radial direction of the communicating portion  32  at the end on the living body-side of the communicating portion  32 . In the embodiment, the fixing portion  31  is formed in a flange shape to surround the communicating portion  32 . The fixing portion  31  is formed in a plate shape provided with the communication path  323  of the communicating portion  32  passing therethrough. As shown in  FIGS. 1 and 2 , in the fixing portion  31 , a plurality of countersink portions  33  each being a concave portion are provided on a first surface on the first opening  321  side. In the countersink portion  33 , the skin tissues can enter the space of the concave portion, which countersink portion  33  is provided in a grinding bowl shape. 
     The fixing portion  31  of the fixing device  3 , as shown in  FIG. 4 , has a porous portion  31   a  capable of inducing cells to the space of the porous portion  31   a  and a flat portion  31   b  that allows the cells to be adhered thereto. 
     The porous portion  31   a  has a plurality of pores having a pore diameter to induce the cells into the pores. The porous portion  31   a  is, of the fixing portion  31 , a part in which a large number of pores into which the cells can enter to be fixed thereto are formed. While a single pore that allows the cells to invade thereinto can be provided in a plurality in the porous portion  31   a , the porous portion  31   a  preferably has a porous layer in which a plurality of pores are communicatively connected three-dimensionally. The skin S is fixed to the porous portion  31   a  by inducing the cells in the thickness direction of the porous portion  31   a  (in the downward direction in  FIG. 5 ) to pores (air gaps) formed in the porous portion  31   a . As long as the cells can invade and grow in the porous portion  31   a , the material for the porous portion  31   a  or the size of the pores is not particularly limited. For the porous portion  31   a , a porous material known in the medical field, such as a mesh-shaped titanium fiber may be used, for example. As the porous portion  31   a  is a part fixing the fixing device  3  to the skin, the porous portion  31   a  is preferably a hard member and is more preferably made of a metal such as titanium. Moreover, it is preferable that the porous portion  31   a  is provided integrally with the fixing portion  31  and it is more preferable that the porous portion  31   a  is provided integrally with the fixing device  3 . 
     The flat portion  31   b  has a substantially flat surface and has primarily a function of causing the cells to adhere to the surface of the flat portion  31   b . A material for the flat portion  31   b  is not particularly limited as long as the cells can adhere to the surface SF 2  of the flat portion  31   b . The flat portion  31   b  may be configured by a material having a high biocompatibility, such as titanium or a titanium alloy, for example. Furthermore, the flat portion  31   b  may be made to have a desired surface condition by providing the material having the high biocompatibility with a publicly-known surface treatment such as a mirror surface process or a blasting process (particularly a grit blasting process). 
     The communicating portion  32  communicates the inside of the living body and the outside of the living body. In the embodiment, the communicating portion  32  is a portion through which an inserting member such as the driveline  2  is inserted and is configured in a substantially cylindrical shape. The communicating portion  32  has an opening for the inside of the living body and an opening for the outside of the living body. The communicating portion  32  has the first opening  321 , a second opening  322 , and the communication path  323  formed between the first opening  321  and the second opening  322 . Moreover, in the embodiment, the communicating portion  32  has a communicating portion inclined surface  323   a  provided at the inner surface of the communication path  323  such that the inner diameter is reduced from the first opening  321  toward the second opening  322 , and a female screw portion  323   b  provided on the inner peripheral surface of the first opening  321 . In each of the drawings, illustration of the screw groove of the female screw portion  323   b  is omitted. 
     The first opening  321  is an opening opened toward the outside of the living body when the fixing device  3  is fixed beneath the skin, while the second opening  322  is an opening opened toward the inside of the living body when the fixing device  3  is fixed beneath the skin. The first opening  321  is formed such that the opening surface thereof is orthogonal with respect to the axial direction of the communicating portion  32 . The second opening  322  is formed such that the opening surface thereof is non-orthogonal with respect to the axial direction of the communicating portion  32 . The cross section of the first opening  321  is formed in a circular shape, and the diameter of the first opening  321  in the cross section is substantially same as the outer diameter of a screw member  42  to be described below. The cross section of the second opening  322  is formed in an elliptical shape, and the cross-sectional area of the second opening  322  is formed to be greater than the cross-sectional area of the driveline  2  when the driveline  2  is cut in a direction being parallel to the second opening  322 . 
     The communication path  323  is a path to communicate the first opening  321  and the second opening  322 . The communication path  323  is formed in a circular shape in a cross sectional view. The communication path  323  is configured such that the central axis thereof forms one straight line. While the communication path  323  is formed such that the central axis thereof forms one straight line, it is not limited thereto. The communication path  323  may be formed to be curved or bent at the intermediate portion of the communication path  323 , for example. Moreover, in the embodiment, the communication path  323  is configured to be inclined with respect to the fixing portion  31 , but the inclined angle is not particularly limited. Furthermore, the communication path may be formed to be orthogonal to the target. 
     The communicating portion inclined surface  323   a  is a portion provided on the inner surface of the communication path  323  and is provided such that the inner diameter thereof is reduced toward the second opening  322  from the first opening  321 . The communicating portion inclined surface  323   a  is provided such that the inclined angle of the communicating portion inclined surface  323   a  is constant. In other words, the communicating portion inclined surface  323   a  is configured in a straight-line shape in the cross section shown in  FIG. 1 . While the communicating portion inclined surface  323   a  is formed such that the inclined angle thereof is constant in the embodiment, it is not limited thereto. For example, the communicating portion inclined surface  323   a  may also be formed such that the inclined angle of the communicating portion inclined surface  323   a  increases toward the second opening  322 . In this case, the communicating portion inclined surface is configured such that the cross section shown in  FIG. 1  is in a curved shape. 
     The female screw portion  323   b  is a portion provided on the inner peripheral surface of the first opening  321 . A male screw portion  42   c  to be described below screws into the female screw portion  323   b.    
     In the embodiment, the holding structure  4  is a structure so that the fixing device  3  holds the driveline  2  in a liquid-tight manner to keep inside of the body in a liquid-tight manner. The holding structure  4  comprises a chuck member  41 , a screw member  42 , and a sealing member  43 . 
     The chuck member  41  is a member to tighten and grasp an inserting member such as the driveline  2 . The chuck member  41  has a fixing device-side contacting portion  41   a  which is provided on an outer periphery of one end side of the chuck member  41  and contacts the communicating portion inclined surface  323   a , a screw member-side contacting portion  41   b  which is provided on an outer peripheral surface on the other end side of the chuck member  41  and contacts the screw member  42 , a fitting portion  41   c  which is provided on the inner side and fits to the outer periphery of the driveline  2  in close contact therewith, and a sealing member-side contacting portion  41   d  to contact the sealing member  43 . The chuck member  41  is a member to be arranged between the inner wall of the communicating portion  32  and the outer surface of the driveline  2 . The chuck member  41  has, in the holding structure  4 , a role of holding the driveline  2  by tightening the driveline  2  and a role of achieving liquid tightness. A material for the chuck member is not particularly limited. A material capable of being slightly deformed such as to make it possible to tighten the driveline  2  may be used as a material capable of achieving the role of holding the insertion target and the role of achieving the liquid tightness. The chuck member  41  in the embodiment is formed of a metal having a high corrosion resistance, which metal has the hardness equivalent to that of a material forming the fixing device  3  or the hardness lower than that of the material forming the fixing device  3 . The metal having the high corrosion resistance may be titanium or a titanium alloy, for example. 
     In a state where the chuck member  41  is arranged in the communicating portion  32 , the fixing device-side contacting portion  41   a  is a contacting portion provided at an end on the second opening  322  side and is a portion which contacts the communicating portion inclined surface  323   a . The fixing device-side contacting portion  41   a  is configured to contact the communicating portion inclined surface  323   a  such that a force in a direction in which the chuck member  41  is reduced in diameter (a force toward the driveline  2 ) is applied to the chuck member  41  from the communicating portion inclined surface  323   a . In the embodiment, the inclined angle of the fixing device-side contacting portion  41   a  is identical to that of the communicating portion inclined surface  323   a . In other words, the fixing device-side contacting portion  41   a  is configured to contact the communicating portion inclined surface  323   a  in a surface contact with the communicating portion inclined surface  323   a . In other words, an inclined surface having identical inclined angle to that of the communicating portion inclined surface  323   a  is preferably formed in at least one portion of the fixing device side contacting portion  41   a.    
     The screw member-side contacting portion  41   b  is a contacting portion provided at an end on the first opening  321  side in a state where the chuck member  41  is arranged in the communicating portion  32  to contact the screw member  42 . The screw member-side contacting portion  41   b  is configured as a part of an inclined surface formed on the first opening  321  side of the chuck member  41 . The screw member-side contacting portion  41   b  is configured to contact the tip contacting portion  42   a  of the screw member  42  (described below) such that a force in the direction in which the chuck member  41  is reduced in diameter (a force toward the driveline  2 ) is applied to the chuck member  41  from the tip contacting portion  42   a . Moreover, the tip contacting portion  42   a  of the screw member  42  also receives, from the screw member-side contacting portion  41   b , a force outwardly in a radial direction of the screw member  42 . In the embodiment, the screw member-side contacting portion  41   b  is configured by an inclined surface whose inclined angle is identical to that of the tip contacting portion  42   a  being an inclined surface. In other words, the screw member-side contacting portion  41   b  is configured to contact the tip contacting portion  42   a  in a surface contact with the tip contacting portion  42   a . In other words, an inclined surface having inclined angle identical to that of the tip contacting portion  42   a  is preferably formed in at least one portion of the screw member-side contacting portion  41   b.    
     While the screw member-side contacting portion  41   b  is configured with an inclined surface, it is not limited thereto. It suffices that the screw member-side contacting portion  41   b  has a shape capable of receiving a force from the screw member  42  in a direction in which the chuck member  41  is at least pushed toward the second opening  322  side. 
     The fitting portion  41   c  is a portion to fit to the outer periphery of the driveline  2  in close contact therewith. In the embodiment, the fitting portion  41   c  is the entire inner peripheral surface of the chuck member  41 . In the embodiment, the chuck member  41  has a communicating hole to communicate an opening at a side of the first opening  321  and an opening at a side of the second opening  322  and grasps the driveline  2  such that the driveline  2  extends out of these openings, and the fitting portion  41   c  is the entire inner peripheral surface of the communicating hole of the chuck member  41 . 
     The fitting portion  41   c  is formed in a circular shape in a cross section and is formed such that the diameter of the cross section of the fitting portion  41   c  is uniform as shown in  FIG. 1 . While the fitting portion  41   c  is formed such that the diameter of the cross section thereof is uniform, it is not limited thereto. The fitting portion  41   c  may have a step portion formed such that the diameter of the cross section increases in the central region of the fitting portion  41   c , for example. 
     The sealing member-side contacting portion  41   d  is a contacting portion provided at an end on the first opening  321  side in a state where the chuck member  41  is arranged in the communicating portion  32  to contact the sealing member  43 . The sealing member-side contacting portion  41   d  is configured with a part of the inclined surface formed on the first opening  321  side of the chuck member  41  and a surface being parallel to the radial direction of the communicating portion  32 . The sealing member-side contacting portion  41   d  is continuously formed with the screw member-side contacting portion  41   b . While the sealing member-side contacting portion  41   d  is configured with the part of the inclined surface formed on the first opening  321  side of the chuck member  41  and the surface being parallel to the radial direction of the communicating portion  32 , it is not limited thereto. It suffices that the sealing member-side contacting portion  41   d  has a shape capable of receiving a force from the sealing member  43  in a direction in which the chuck member  41  is pushed toward the second opening  322  side. 
     As shown in  FIG. 2 , the chuck member  41  in the embodiment configured by a first chuck member  411  and a second chuck member  412 . The chuck member  41  may be divided in the radial direction and may be a substantially tubular body by integrally joining them. The chuck member  41  is formed when a joining surface  411   a  of the first chuck member  411  and a joining surface  412   a  of the second chuck member  412  are joined. Moreover, the chuck member  41  has a concave portion  41   e  on the outer peripheral surface of the chuck member  41 . The concave portion  41   e  is provided in order to stop sliding of the chuck member  41  when the chuck member  41  is attached to the insertion target. The structure of the chuck member  41  is not limited to the structure capable of being divided in the radial direction. The chuck member  41  may be configured as the structure capable of being divided in the axial direction or the structure not capable of being divided. 
     The screw member  42  is a member being screwed into the female screw portion  323   b  being provided on the inner peripheral surface of the first opening  321  to close the first opening  321  and hold the driveline  2 . The screw member  42  has a screw member inserting path  42   b  through which the driveline  2  is inserted, a male screw portion  42   c  provided on the outer peripheral surface, a tip portion  42   d  to be inserted into the communicating portion  32 , a tip contacting portion  42   a  provided on the inner side of the tip portion  42   d  to contact the screw member-side contacting portion  41   b , and a screw member fitting portion  42   e  to fit to the sealing member  43 . The screw member  42  is arranged between the inner wall of the communicating portion  32  and the outer peripheral surface of the sealing member  43  and between the inner peripheral surface of the communicating portion  32  and the outer peripheral surface of the chuck member  41 . The screw member  42  has, in the holding structure  4 , a role of closing the first opening  321 , a role of pressing the chuck member  41  and the sealing member  43 , and a role of holding the driveline  2 . A material for the screw member is not particularly limited as long as the material is capable of achieving the role of closing the first opening  321 , the role of pressing the chuck member  41  and the sealing member  43 , and a role of holding an insertion target. In the embodiment, the screw member  42  is formed of a metal having a high corrosion resistance, which metal has the hardness equivalent to that of a material forming the fixing device  3  or the hardness lower than that of the material forming the fixing device  3 . The metal having the high corrosion resistance may be titanium or a titanium alloy, for example. 
     The screw member inserting path  42   b  is a path provided inside the screw member  42  to insert the driveline  2  through the screw member  42 . The screw member inserting path  42   b  is provided from an end of the screw member  42  on the outer side of the living body to the intermediate portion of the screw member  42 . The diameter of the screw member inserting path  42   b  is substantially same as the outer diameter of the driveline  2 . 
     The male screw portion  42   c  is a portion provided on the outer peripheral surface of the screw member  42  to be screwed into the female screw portion  323   b.    
     The tip portion  42   d  is a portion to be inserted into the communicating portion  32  of the fixing device  3 , and the male screw portion  42   c  is provided on the outer peripheral surface thereof. In each of the drawings, illustration of threads of the male screw portion  42   c  may be omitted. 
     The tip contacting portion  42   a  is a portion being provided on the inner peripheral surface of the tip portion  42   d  to contact the screw member-side contacting portion  41   b . The tip contacting portion  42   a  is a portion to contact the screw member-side contacting portion  41   b  configuring the chuck member  41  and is configured with an inclined surface having an inclined angle being identical to the inclined angle of the inclined surface of the screw member-side contacting portion  41   b . The tip contacting portion  42   a  is formed continuously with the screw member fitting portion  42   e . While the tip contacting portion  42   a  is configured with an inclined surface having an inclined angle being identical to the inclined angle of the inclined surface of the screw-member side contacting portion  41   b , the tip contacting portion  42   a  is not limited thereto. It suffices that the tip contacting portion  42   a  has a shape capable of transmitting a force from the screw member  42  in a direction in which the chuck member  41  is pushed toward the second opening  322  by contacting at least a part of the tip contacting portion  42   a  with the screw-member side contacting portion  41   b.    
     The screw member fitting portion  42   e  is a portion to fit to the sealing member  43 . A pressing surface Sa to press the sealing member  43  in the axial direction of the driveline  2  is provided to the screw member fitting portion  42   e . As shown in  FIG. 3 , the screw member fitting portion  42   e  has the pressing surface Sa (See  FIG. 3 ) provided at the first opening  321  side and being parallel to the radial direction, a contact surface Sb being parallel to the outer peripheral surface of the sealing member  43 , and a contact surface Sc being provided such that the inner diameter of the contact surface Sc is reduced toward the second opening  322  side from the first opening  321  side. The configuration of the screw member fitting portion is not limited to the configuration shown in the embodiment as long as the screw member fitting portion fits to the sealing member and has the pressing surface. 
     Moreover, the screw member  42  has a receiving portion  42   f  to receive a deformed portion of the sealing member  43  when the sealing member  43  is pressed and deformed. The receiving portion  42   f  is provided on the first opening  321  side of the screw member fitting portion  42   e  and at the inner side (the screw member inserting path  42   b  side) in the radial direction. 
     Furthermore, a concave portion  42   g  to arrange an O-ring  5  is provided on the outer periphery of the screw member  42 . The concave portion  42   g  is provided on the outer peripheral surface of the tip portion  42   d . The O-ring  5  is a member provided between the outer peripheral surface of the screw member  42  and the inner peripheral surface of the communicating portion  32  and has a role of assisting the liquidtightness between the screw member  42  and the communicating portion  32 . The O-ring  5  may be attached to the inner peripheral surface of the communicating portion  32 , not on the outer periphery of the screw member  42 . 
     The sealing member  43  has an inserting member-side pressing portion  43   a  to elastically press the outer periphery of the driveline  2 , a sealing member fitting portion  43   b  to fit to the screw member  42 , and a chuck member-side contact surface  43   c  to contact the chuck member  41  in the circumferential direction of the driveline  2 . The sealing member  43  is a member arranged between the inner peripheral surface of the screw member  42  and the outer surface of the driveline  2 . The sealing member  43  has, in the holding structure  4 , a role of holding the driveline  2  by tightening the driveline  2  and a role of achieving the liquidtightness. It suffices that a material for the sealing member is a material capable of having the role of holding the insertion target through the sealing member by tightening the insertion target and the role of achieving the liquidtightness and, as a representative thereof, an elastic material may be used. For example, the material for the sealing member  43  is preferably an elastic resin material, which elastic resin material includes a single synthetic resin composition such as an elastic silicone resin, and a mixture of a synthetic resin and an inorganic compound. 
     The inserting member-side pressing portion  43   a  is a member to keep the liquidtightness by contacting and elastically pressing the outer surface of the driveline  2 . In the embodiment, the inserting member-side pressing portion  43   a  is configured with a surface being parallel to the outer surface of the driveline  2 . 
     The sealing member fitting portion  43   b  is a portion to contact the inner surface of the screw member  42 . The sealing member fitting portion  43   b  is a portion to contact the screw member fitting portion  42   e  of the screw member  42 . The sealing member fitting portion  43   b  has a contact surface being parallel to the pressing surface Sa formed on the first opening  321  side, a contact surface being parallel to the contact surface Sb of the screw member fitting portion  42   e , and a contact surface provided such that the inner diameter thereof is reduced toward the second opening  322  side from the first opening  321  side. 
     The chuck member-side contact surface  43   c  is a portion to contact the chuck member  41 . The chuck member-side contact surface  43   c  is a portion to contact the sealing member-side contacting portion  41   d , and is configured with an inclined surface opposing a part of an inclined surface formed on the first opening  321  side of the chuck member  41  and a surface extended parallel to the radial direction of the communicating portion  32 . The chuck member-side contact surface  43   c  is formed continuously with the sealing member fitting portion  43   b . While the chuck member-side contact surface  43   c  is configured with the inclined surface opposing the part of the inclined surface formed on the first opening  321  side of the chuck member  41  and the surface extended parallel to the radial direction of the communicating portion  32 , the chuck member-side contact surface  43   c  is not limited thereto. It suffices that the chuck member-side contact surface  43   c  has a shape capable of transmitting a force from the sealing member  43  in a direction in which the chuck member  41  is pushed toward the second opening  322  by contacting at least a part of the chuck member-side contact surface  43   c  with the chuck member  41 . 
     &lt;Assembling of Holding Structure of Driveline&gt; 
     Next, an assembling method of the holding mechanism assembly  1  will be described using  FIGS. 1 to 3 . 
     The driveline  2  is inserted through the communicating portion  32  of the fixing device  3 . For example, the driveline  2  extending to the outside of the living body from a hole provided in the skin S is inserted through the communicating portion  32  of the fixing device  3  by inserting the driveline  2  from the second opening portion  322  of the fixing device  3  to the first opening  321  side. 
     Moreover, the chuck member  41  is arranged on the outer periphery of the driveline  2 . Specifically, the fitting portion  41   c  of the second chuck member  412  is contacted with the outer periphery of the driveline  2  while contacting the fitting portion  41   c  of the first chuck member  411  configuring the chuck member  41  is contacted with the outer periphery of the driveline  2 . Joining the joining surface  411   a  of the first chuck member  411  and the joining surface  412   a  of the second chuck member  412  causes the chuck member  41  to be arranged on the outer periphery of the driveline  2 . 
     The chuck member  41  is inserted into the communicating portion  32  from the first opening  321  side. While the fixing device-side contacting portion  41   a  of the chuck member  41  inserted into the communicating portion  32  will contact the communicating portion inclined surface  323   a  of the communicating portion  32 , it does not necessarily have to contact the communicating portion inclined surface  323   a  of the communicating portion  32  at this time. Next, the sealing member  43  is fitted to the outer periphery of the driveline  2  such that the sealing member  43  is on the upper side (the first opening  321  side) of the chuck member  41 . Thereafter, the screw member  42  to which the O-ring  5  is fitted is fitted to the outer periphery of the driveline  2  such that the screw member  42  is on the upper side (the first opening  321  side) of the sealing member  43 . Then, the male screw portion  42   c  of the screw member  42  is screwed into the female screw portion  323   b  of the communicating portion  32 . The screw member  42  moves toward the second opening  322  side of the fixing device  3  by screwing the male screw portion  42   c  into the female screw portion  323   b.    
     By screwing the male screw portion  42   c  of the screw member  42  into the female screw portion  323   b  of the communicating portion  32 , the tip contacting portion  42   a  of the screw member  42  moves toward the second opening  322 , and the tip contacting portion  42   a  presses the screw member-side contacting portion  41   b  of the chuck member  41 . The chuck member-side contact surface  43   c  of the sealing member  43  presses the sealing member-side contacting portion  41   d  of the chuck member  41 . At that time, in a case that the chuck member  41  has not been contacted with the communicating portion inclined surface  323   a  of the communicating portion  32 , the chuck member  41  moves toward the second opening  322  side and the fixing device-side contacting portion  41   a  of the chuck member  41  contacts the communicating portion inclined surface  323   a  of the communicating portion  32 . Then, as screwing of the male screw portion  42   c  into the female screw portion  323   b  proceeds, the movement of the chuck member  41  is regulated so that a force to bring the driveline  2  into close contact with the fixing device  3  to hold the fixing device  3  is generated. This makes it possible to assemble the holding mechanism assembly  1  comprising the holding structure  4  having a high close contactability. 
     The above-described assembling procedure is one example, so that the assembling procedure up to causing the male screw portion  42   c  of the screw member  42  to be screwed into the female screw portion  323   b  of the communicating portion  32  is not particularly limited. 
     The structure of the above-described holding mechanism assembly  1  is merely one example, so that the structure of the holding mechanism assembly is not limited to the embodiment. 
     At the time attaching of the holding mechanism assembly  1  to the living body is completed, as shown in  FIG. 5 , a space SP is formed, on the second opening  322  side of the communication path  323  with respect to the holding structure  4 , between the inner wall of the communicating portion  32 , which defines the communication path  323 , and an outer surface  2   a  of the driveline  2 . The space SP is a space formed outward of the outer surface  2   a  of the driveline  2  in the radial direction between an end E on the second opening  322  side of the holding structure  4  and the opening edge of the second opening  322 . When a predetermined time period has passed after the holding mechanism assembly  1  being attached to the living body, the space SP is changed from a state such that cells have not reproduced in the space SP (a state shown in  FIG. 5 ) to a state as shown in  FIG. 1 , in which the cells has reproduced to cause the space SP to be filled up with the reproduced cells. 
     As a result of intensive studies, the inventor has found that inflammation occurring in the site at which the fixing device  3  is fixed to the skin S, the cause of which inflammation was not known conventionally, occurs in a case that the driveline  2  is covered with fiber at a position corresponding to the space SP. That is, the inventor has found that the cause of the damage of the cells is a force being applied in the direction in which cells entering into the fiber and cells in the space SP are peeled off due to a relative movement of the driveline  2  in a case that the driveline  2  is covered with fiber at the position corresponding to the space SP. Then, the embodiment makes it possible to suppress cells being damaged by providing the driveline  2  with a non-covered region A 2  (described below) at a predetermined position. Below, this point will be described in detail. 
     According to the embodiment, as shown in  FIGS. 1 and 5 , the outer surface  2   a  of the driveline  2  has a covered region A 1  covered with fiber that can guide cells and the non-covered region A 2  not covered with fiber, and the non-covered region A 2  of the driveline  2  extends between the holding structure  4  and the second opening  322  in the communication path  323 . 
     The covered region A 1  is a region of the outer surface  2   a  of the driveline  2 , which is covered with fiber that can guide the cells. A material for the fiber constituting the covered region A 1  is not particularly limited as long as the cells can be guided and the material is not harmful to the living body. For example, a polyester fiber can be used for the covered region A 1 . The structure of the covered region A 1  constituted by fiber is not particularly limited as long as the cells can be guided. It is preferable that the covered region A 1  is formed in a porous shape, for example. The growth of cells is promoted in the covered region A 1  by the covered region A 1  formed in a porous shape causing cells to enter into a plurality of air gaps formed in the covered region A 1 . 
     The non-covered region A 2  is a region of the outer surface  2   a  of the driveline  2 , in which the fiber that can guide the cells is not provided. As shown in  FIG. 5 , the non-covered region A 2  is provided at a position of the communication path  323  between the holding structure  4  and the second opening  322 , or in other words opposes the space SP in the radial direction of the driveline  2 . Since the fiber is not provided in the non-covered region A 2 , it is suppressed that cells growing into the space SP are fixed to the outer surface  2   a  of the driveline  2  as described below. Here, the cells being “fixed” refers to a state in which, as in the fiber of the covered region A 1 , for example, the cells grow inwardly in the radial direction of the driveline  2  to enter into pores formed in the fiber and the cells are fixed to the driveline  2 . In the embodiment, the non-covered region A 2  has a surface such that damaging of cells invading into the space SP is suppressed when the fixing device  3  moves relatively in the axial direction and/or the radial direction of the driveline  2  with respect to the driveline  2 . 
     Next, functions and effects of the holding mechanism assembly  1  in the embodiment will be described. In the embodiment, as shown in  FIGS. 1 and 5 , the non-covered region A 2  of the driveline  2  extends between the holding structure  4  and the second opening  322 . This makes it possible to suppress the cells being damaged in the space SP formed between the outer surface  2   a  of the driveline  2  and the inner wall of the communicating portion  32 . Below, functions and effects of the embodiment will be described in further detail, along with a reference example of a case in which the non-covered region A 2  is not provided. 
     As shown in  FIG. 6 , in case that the covered region A 1  has the fiber provided at a position opposing the space SP, cells C invading into the space SP (see  FIG. 5 ) between the outer surface  2   a  of the driveline  2  and the inner wall of the communicating portion  32  grow inwardly in the radial direction of the driveline  2  toward pores, which are formed with the fiber, of the covered region A 1 . Thus, the cells C enter into complex and intricate pores of the covered region A 1  to be firmly fixed to the driveline  2 . In this state, if the living body performs an action and the fixing device  3  moves with respect to the skin S, as shown in  FIG. 6 , for example, the driveline  2  and the fixing device  3  move relatively with respect to each other such that the distance between the outer surface  2   a  of the driveline  2  and the inner wall of the communicating portion  32  increases. Alternatively, the cells in the space SP and the outer surface  2   a  of the driveline  2  can move relatively in the axial direction of the driveline  2  when the driveline  2  is pulled in the axial direction of the driveline  2 , for example. In this way, in case that the outer surface of the driveline  2  moves relatively in the axial direction and/or radial direction of the driveline  2  with respect to the cells C in the space SP, as shown in  FIG. 6 , cells C 2  entering into the fiber in the covered region A 1  are peeled off in the radial direction of the driveline  2  or peeled off in the axial direction of the driveline  2  from cells C 1  positioned in the space SP. 
     On the other hand, in the embodiment, as shown in  FIGS. 1 and 5 , the non-contact region A 2  not covered with fiber extends between the holding structure  4  and the second opening  322 . Thus, as shown in  FIG. 7 , since intricate pores formed with fiber is not present, the cells C invading into the space SP is not fixed to the outer surface  2   a  of the driveline  2 . Therefore, as shown in  FIG. 7 , even when the driveline  2  and the fixing device  3  move relatively with each other such that the distance between the outer surface  2   a  of the driveline  2  and the inner wall of the communicating portion  32  increases, the cells invading into the space SP are easily separated from the outer surface  2   a  of the driveline  2  so that damage of the cells C is suppressed. Similarly, also when the driveline  2  moves relatively in the axial direction of the driveline  2  with respect to the cells in the space SP, the cells C are easily separated from the outer surface  2   a  of the driveline  2  so that damage of the cells C is suppressed. Therefore, the holding mechanism assembly  1  according to the embodiment makes it possible to suppress the cells being damaged in the space SP formed between the outer surface  2   a  of the driveline  2  and the inner wall of the communicating portion  32 . 
     The structure of the non-covered region A 2  is not particularly limited as long as the non-covered region A 2  is not covered with fiber and the grown cells in the space SP being fixed to the driveline  2  is suppressed. The non-covered region A 2  is preferably formed with a smooth curved surface. In case that the non-covered region A 2  is formed with the smooth curved surface, it is suppressed that the cells invading into the space SP is fixed to the non-covered region A 2 . Thus, if a relative movement between the outer surface  2   a  of the driveline  2  and the cells occurs, the outer surface  2   a  of the driveline  2  and the cells invading into the space SP are easily separated from each other so that damage of cells is further suppressed. As long as the outer surface  2   a  of the driveline  2  is smooth, the non-covered region A 2  may be in a state in which the tube body of the driveline  2  has no coating, that is, a state in which the material itself of the tube body of the driveline  2  is exposed to the surface, or the tube body of the driveline  2  has a coating with a material other than fiber. A material forming the non-covered region A 2  is not particularly limited as long as it is a biocompatible material. The material of the non-covered region A 2  may be a synthetic resin, for example. 
     In the embodiment, the driveline  2  inserted into the fixing device  3  is configured such that the covered region A 1  is arranged in a predetermined region at a side toward the inside of the living body with respect to the second opening  322  as shown in  FIGS. 1, 5 and 7 . In this way, while suppressing the cells being damaged in the space SP, the cells are fixed to the covered region A 1  of the outer surface  2   a  of the driveline  2  in a position at a side toward the inside of the living body in the vicinity of the second opening  322  of the fixing device  3 . The holding mechanism assembly  1  has the holding structure  4  in which the fixing device  3  firmly holds the inserting member  2 , the non-covered region A 2  may be provided between the holding structure  4  and the covered region A 1 . The holding mechanism assembly  1  having the covered region A 1  allows stabilizing the driveline  2  inside the living body to promote healing of the incised site. In a region at a side toward the living body with respect to the second opening  322  of the fixing device  3 , influence of the relative movement of cells with respect to the driveline  2  of the fixing device  3  is smaller compared to the surface side of the skin S. The predetermined region of the driveline  2  at a side toward the living body with respect to the second opening  322  is not particularly limited as long as the predetermined region is in the vicinity of the second opening  322  and cells can be fixed in the covered region A 1  of the driveline  2 . For example, in the covered region A 1 , it is preferable that a depth D at the deepest portion of an end (a border between the covered region A 1  and the non-covered region A 2 ) E 2  of the covered region A 1  in  FIG. 1  from the opening edge of the second opening  322  is set to be less than or equal to 7-10 mm (or D≤10 to 15 mm). In this case, it is possible to grow cells across the entire outer periphery of the fiber of the covered region A 1  of the driveline  2  to promote healing of the incised site while suppressing the cells being damaged. In the embodiment, the covered region A 1  is provided such that the end E 2  of the covered region A 1  extends in a direction being perpendicular to the axial direction of the driveline  2 . However, as shown with a double-dashed line E 20  in  FIG. 5 , the end of the covered region A 1  may extend so as to be parallel to the opening edge of the second opening  322  of the fixing device  3 . 
     EXPLANATIONS OF LETTERS 
     
         
         
           
               1  HOLDING MECHANISM ASSEMBLY 
               2  DRIVELINE (INSERTING MEMBER) 
               2   a  OUTER SURFACE OF DRIVELINE 
               21  COOLING WATER CIRCULATION PATH 
               22  POWER CABLE 
               3  FIXING DEVICE 
               31  FIXING PORTION 
               31   a  POROUS PORTION 
               31   b  FLAT PORTION 
               32  COMMUNICATING PORTION 
               321  FIRST OPENING 
               322  SECOND OPENING 
               323  COMMUNICATION PATH 
               323   a  COMMUNICATING PORTION INCLINED SURFACE 
               323   b  FEMALE SCREW PORTION 
               33  COUNTERSINK PORTION 
               4  HOLDING STRUCTURE 
               41  CHUCK MEMBER 
               41   a  FIXING DEVICE-SIDE CONTACTING PORTION 
               41   b  SCREW MEMBER-SIDE CONTACTING PORTION 
               41   c  FITTING PORTION 
               41   d  SEALING MEMBER-SIDE CONTACTING PORTION 
               41   e  CONCAVE PORTION 
               411  FIRST CHUCK MEMBER 
               411   a  JOINING SURFACE 
               412  SECOND CHUCK MEMBER 
               412   a  JOINING SURFACE 
               42  SCREW MEMBER 
               42   a  TIP CONTACTING PORTION 
               42   b  SCREW MEMBER INSERTING PATH 
               42   c  MALE SCREW PORTION 
               42   d  TIP PORTION 
               42   e  SCREW MEMBER FITTING PORTION 
               42   f  RECEIVING PORTION 
               42   g  CONCAVE PORTION 
               43  SEALING MEMBER 
               43   a  INSERTING MEMBER-SIDE PRESSING PORTION 
               43   b  SEALING MEMBER FITTING PORTION 
               43   c  CHUCK MEMBER-SIDE CONTACT SURFACE 
               5  O RING 
             A 1  COVERED REGION 
             A 2  NON-COVERED REGION 
             C, C 1 , C 2  CELLS 
             E END ON SECOND OPENING SIDE OF HOLDING STRUCTURE 
             E 2  END OF COVERED REGION 
             S SKIN 
             Sa PRESSING SURFACE 
             Sb CONTACT SURFACE 
             Sc CONTACT SURFACE 
             SP SPACE