Abstract:
A catheter introducer includes a tube having a proximal end, a distal end and a lumen extending therethrough along a longitudinal axis of the tube for accommodating a catheter traveling along a longitudinal axis of the tube and a head portion coupled to the distal end of the tube. The head portion includes an aperture in fluid communication with the lumen at a proximal end thereof and a tip at a distal end thereof, an exterior surface extending from the proximal end thereof to an opening of the head portion along a first portion of the head portion and extending from the proximal end thereof to the tip along an opposing portion of the head portion and an interior surface extending from the aperture to the opening of the head portion along the first portion of the head portion and extending from the aperture toward the tip along the opposing portion of the head portion. The exterior surface circumferentially tapers from the proximal end to the distal end and the interior surface forms a channel for receiving a catheter passing through the lumen and the aperture, the channel being concave along at least one axis.

Description:
FIELD OF THE INVENTION 
   The invention relates generally to medical devices and more particularly to catheter introducing devices. 
   BACKGROUND OF THE INVENTION 
   During surgical procedures, catheter introducers are often used to provide a conduit for passage of catheters and other relatively long, thin and flexible medical devices, for example, guide wires, into lumens in a patient. For example, in cholangiography procedures, an introducer is used to establish a guide channel to permit advancement of a catheter to an incision in the wall of the cystic duct of the gallbladder. The catheter is introduced through the introducer, under control of the surgeon, and is extended out of the introducer. The distal tip of the catheter is manipulated by the surgeon into the incision in the cystic duct, and navigated by the surgeon through the lumen of the cystic duct forward and through the valve of Heister. During this procedure, the valves or other obstructions can inhibit the catheter&#39;s advancement in the duct. 
   Prior art catheter introducers include a cannula and a hub mounted on a proximal end of the cannula. The cannula is generally straight in profile, and the catheter passes through the distal end of the cannula along the same axis as the cannula. During the surgical procedure, the surgeon typically approaches the cystic duct at some oblique angle to its longitudinal axis. Depending on the approach angle, a straight introducer may direct the catheter directly into the opposite wall of the duct, and may require pushing against the back wall of the duct in order to bend the catheter and direct it into the lumen of the duct. The elasticity of the duct wall makes such a procedure very difficult. 
   Some prior art introducers utilize a curved distal end to direct the catheter into the cystic duct. The curved introducers represent an improvement over the straight introducers, but still do not provide the support and control necessary for optimized catheter insertion. In general, both straight and curved introducers share a common problem. Laparoscopic procedures are difficult to execute because the surgeon is operating with instruments on an extended lever arm. For a cholangiography, a catheter must be inserted into a small incision in the cystic duct, the narrowest of the extra-hepatic ducts, which is generally 3 to 7 mm in diameter. With existing cholangiography procedures, the surgeon must be able to transmit navigation motions to insure that the catheter is properly inserted into the incision in the duct. Existing introducers do not have a tip which is optimized for providing access of the catheter to the cystic duct. While existing introducers may enable the surgeon to navigate the end of the catheter proximate the incision, they still require that the surgeon enter the incision with the end of the catheter, which can be difficult, given the necessary flexibility of the catheter, the diameter of the catheter and the typical dimensions of the incision. 
   What is needed is an improved catheter introducer which may be easily inserted into the cystic duct, and may be easily manipulated for laparoscopic cholangiograms. 
   SUMMARY OF THE INVENTION 
   The present invention provides a catheter introducer device including a tapered tip which facilitates insertion of the catheter into the cystic duct. 
   A catheter introducer includes an elongated tube extending from a proximal end to a distal end along a longitudinal axis and a direction translation device. The tube has a lumen for accommodating a catheter. The direction translation device, which may include a scoop-shaped, spoon-shaped or straight head portion, extends from the distal end of tube. The head portion includes an upper surface in connection with the lumen, a lower surface extending from the outer surface of said tube, a distal tip, and a catheter receiving portion formed between the lumen and the tip. The catheter receiving portion is defined by a two-axis concave surface extending from the interior surface of central lumen to the distal tip. The distal tip may be pointed, bill-shaped, or channeled. The concave surface of the catheter receiving portion and the distal tip form a path for guiding an inserted catheter, such that a lead end of the catheter traveling through the lumen contacts the concave surface of the catheter receiving portion upon exiting the lumen and is forced to travel in a direction oblique to the longitudinal axis. For properly guiding the catheter to a desired direction, and for properly placing the catheter in a duct, the catheter receiving portion may be constructed substantially straight, or slightly curved, or substantially curved corresponding to the shape of the duct or the requirement of a surgery procedure. 
   In one embodiment, the protrusion is scoop-shaped. The protrusion has a width, which monotonically decreases from the distal end of the tube to the distal tip of the protrusion. In another embodiment, the width of the protrusion monotonically decreases from a point between the distal end of the tube and the distal tip of the protrusion to the distal tip of the protrusion. 
   In yet another embodiment, the protrusion is spoon-shaped. The spoon-shaped protrusion may have a first width at the base and a second width at an intermediate point between the base and the tip, the second width being greater than the first width. The spoon-shaped protrusion may taper in width from the intermediate point to the tip. The catheter receiving portion of the spoon-shaped protrusion may include a one- or two-axis concave surface for translating a direction of travel of the catheter within the lumen which is parallel to a longitudinal axis of the tube to a direction of travel outside of the lumen which is oblique to the longitudinal axis. 
   In yet another embodiment, the protrusion is substantially straight. The protrusion extends from the distal end of the tube. The straight protrusion design is adapted for introducing an inserted catheter to a direction parallel to the longitudinal axis of the tube. 
   The head portion may be constructed within planes tangent to the outer surface of the tube. The smaller profile design of the head portion allows insertion of the head portion through the incision in the cystic duct, and placement within it. Following such insertion, a catheter may be inserted into the introducer from the proximal end, extended out from the head portion and guided into the lumen of the cystic duct. The curved design of the protrusion also provides good support for the catheter if it encounters resistance from valves or other obstructions. 
   The small profile design of the protrusion also makes it easier for the introducer to be inserted along the lumen of the cystic duct. During operation, electro-cauterization may be utilized to stop any bleeding at the incision site. This may cause the duct tissue to shrink, or a buildup of dead tissue to partially obstruct the lumen of the cystic duct. The leading edge of the tip can be used to pass through this narrowed incision, and then can be positioned for directing catheter insertion in the duct. 
   According to another aspect of the invention, a catheter introducer includes a tube having a proximal end, a distal end and a lumen extending therethrough along a longitudinal axis of the tube for accommodating a catheter traveling along a longitudinal axis of the tube and a head portion coupled to the distal end of the tube. The head portion includes an aperture in fluid communication with the lumen at a proximal end thereof and a tip at a distal end thereof, an exterior surface extending from the proximal end thereof to an opening of the head portion along a first portion of the head portion and extending from the proximal end thereof to the tip along an opposing portion of the head portion and an interior surface extending from the aperture to the opening of the head portion along the first portion of the head portion and extending from the aperture toward the tip along the opposing portion of the head portion. The exterior surface circumferentially tapers from the proximal end to the distal end and the interior surface forms a channel for receiving a catheter passing through the lumen and the aperture, the channel being concave along at least one axis. 
   The interior surface may be curved along a radius of curvature. The radius of curvature may be a nonzero value or infinite. The channel may be concave along two axes. The exterior surface along the first portion of the head portion may completely surround the opening, thereby forming a protruding portion at the tip. The protruding portion may include a flat bill or a pointed tip. The head portion may remain within planes which are tangent to an outer surface of the tube. The channel may deflect the catheter from traveling along the longitudinal axis to a direction oblique to the longitudinal axis as the catheter is directed through the head portion. The head may be constructed such that the catheter exits the opening at an angle which is between zero and thirty degrees with respect to the longitudinal axis. The head portion may be constructed such that the longitudinal axis of the tube passes through the opening or such that the longitudinal axis of the tube intersects the channel. A line connecting the first portion of the exterior surface at the opening and the tip may lie in a plane which is oblique with respect to the longitudinal axis. 
   The present invention also provides a method of using the improved catheter introducer. During operation, the introducer is first guided towards the cystic duct. The head portion of the introducer is then inserted into the incision in the duct, and positioned so that the concave channel of the direction translation device is substantially orthogonal to the longitudinal axis of the duct. The catheter is then advanced down the introducer until it extends out of the head portion and is guided into the lumen of the duct. 

   
     DESCRIPTION OF THE FIGURES 
     Other advantages and novel features will be set forth in the detailed description, taken in conjunction with the accompanying drawings, in which: 
       FIG. 1  is a cross-sectional view of a catheter introducer in accordance with the present invention; 
       FIGS. 2A–2C  are various views of one embodiment of a catheter introducer straight head portion according to the present invention; 
       FIGS. 3A–3C  are various views of another embodiment of a catheter introducer straight head portion according to the present invention; 
       FIGS. 4A–4C  are various views of another embodiment of a catheter introducer straight head portion according to the present invention; 
       FIGS. 5A–5C  are various views of another embodiment of a catheter introducer straight head portion according to the present invention; 
       FIGS. 6A–6C  are various views of another embodiment of a catheter introducer straight head portion according to the present invention; 
       FIGS. 7A–7C  are various views of another embodiment of a catheter introducer straight head portion according to the present invention; 
       FIGS. 8A–8D  are various views of another embodiment of a catheter introducer spoon-shaped head portion according to the present invention; 
       FIGS. 9A–9C  are various views of another embodiment of a catheter introducer spoon-shaped head portion according to the present invention; 
       FIGS. 10A–10C  are various views of another embodiment of a catheter introducer spoon-shaped head portion according to the present invention; 
       FIGS. 11A–11D  are various views of another embodiment of a catheter introducer spoon-shaped head portion according to the present invention; 
       FIGS. 12A–12E  are various views of another embodiment of a catheter introducer scoop-shaped head portion according to the present invention; 
       FIGS. 13A–13C  are various views of another embodiment of a catheter introducer scoop-shaped head portion according to the present invention; 
       FIGS. 14A–14C  are various views of another embodiment of a catheter introducer scoop-shaped head portion according to the present invention; 
       FIGS. 15A–15C  are various views of another embodiment of a catheter introducer scoop-shaped head portion according to the present invention; 
       FIGS. 16A–16D  are various views of another embodiment of a catheter introducer scoop-shaped head portion according to the present invention 
       FIG. 17  is a top perspective view showing the catheter introducer of the present invention introducing a catheter into a cystic duct; and 
       FIG. 18  is a side perspective view showing the catheter introducer of the present invention introducing a catheter into a cystic duct. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   The present invention is directed to a catheter introducer including a tapered tip which facilitates the insertion of the introducer into an incision in a duct, thereby enabling a surgeon to direct the catheter into the duct to the desired location.  FIG. 1  shows a cross-sectional diagram of one embodiment  10  of the invention. As shown in  FIG. 1 , the introducer  10  includes a tube  12  having a lumen  14  along a longitudinal axis  14 . A head portion  18  extends from a distal end  20  of the tube  12 . As shown in  FIGS. 2A–2C , in which  FIG. 2A  is a side view of the head portion  18  of  FIG. 1 ,  FIG. 2B  is a top view of the head portion  18  of  FIG. 1  and  FIG. 2C  is the same cross-sectional view of the head portion  18  of  FIG. 1 , taken along line  2 C— 2 C of  FIG. 2B . As shown in these figures, head portion  18  is extends generally along the longitudinal axis  16  and includes a lumen extension portion  22  having an interior surface  24  which extends from the interior surface  26  of lumen  14  of tube  12 . Head portion  18  further includes an exterior surface  28  which extends from the exterior surface  30  of the tube  12 . As shown in  FIGS. 1 and 2C , the interior surface  24  and the exterior surface  28  converge toward each other to form a tip  32  which, as is described in more detail below, is used to facilitate the insertion of the head portion  18  into an incision in the cystic duct. Lumen extension portion  22  of the head portion  18  terminates at an opening  34  of the head portion  18 , which opening  34  enables a catheter passing through the lumen  14  and lumen extension portion  22  to exit the head portion proximate the tip  32  at an angle which is relatively acute with respect to the relative plane within which the opening  34  lies. As shown in FIGS.  1  and  2 A– 2 C, head portion  18  tapers from its proximal end  38 , adjacent distal end  20  of tube  12  to the tip  32 . This taper occurs along outer sidewalls  31  as well as along exterior surface  28  with respect to two orthogonal planes which intersect along the longitudinal axis  16  of tube  12 . As a result, exterior surface  28  tapers circumferentially inwardly from planes tangential to the exterior surface  30  of tube  12 , the tangential planes being shown in the figures by dashed line  40 . The amount of taper, indicated by reference numerals  36   a  and  36   b , may vary, depending on the particular application and procedural requirements. While the exterior surfaces of the head portion  18  taper as described and shown, the interior surface  24  of the head portion  18  remains parallel to the longitudinal axis  16  such that the direction of travel of the catheter through the head portion  18  remains along the longitudinal axis  16 . 
   In use, a catheter (not shown) is directed through the lumen  14  of the tube  12  into a position in which the distal end of the catheter is located proximate the distal end  20  of the tube  12 . The introducer  10  is brought into close proximity to an incision in the cystic duct and the surgeon inserts the tip  32  of head portion  18  into the incision. Depending on the size of the incision relative to the diameter of the head portion  18 , the surgeon may insert as much as the entire head portion  18  into the incision, thereby aligning the distal end of the catheter with the incision or, preferably inserting the distal end of the catheter into the incision. With the head portion  18  in such a position, the surgeon is then able to navigate the catheter into the cystic duct and through any obstruction within the duct, with the aid of the head portion  18  and particularly tip  32 . 
   As shown in  FIGS. 2A–2C , this embodiment includes a channel  42  formed between the lower interior surface  24  which extends from the proximal end  38  of the head portion  18  to the tip  32  and interior sidewalls  33  and which, by the nature of the interior surface of the lumen, is concave around the longitudinal axis. The catheter rides within this channel as it is directed out of the opening  34  and through the duct.  FIGS. 3A–3C  show another embodiment  44  of the straight head portion  18 . This embodiment is similar to that shown in  FIGS. 2A–2C , with the exception that the channel  22  terminates at a lip  46   a  of the tip  32 . In this embodiment, lip  46   a  is formed to be continuous with exterior portion  48  of the head portion. 
   Shown in  FIGS. 4–7  are various configurations of the lip  46 . Each configuration is advantageous in enabling the surgeon to insert the tip and head portion into the incision in the cystic duct and through the valves and other obstructions in the duct that may be encountered by the surgeon during the procedure, while reducing the chance of causing any damage within the duct with the tip of the head portion.  FIGS. 4A–4C  show an embodiment  50  of the straight head portion, including a lip  46   b  which is in the form of a flat bill shape.  FIGS. 5A–5C  show an embodiment  52  of the straight head portion, including a lip  46   c  which is in the form of an extended flat bill shape.  FIGS. 6A–6C  show an embodiment  54  of the straight head portion, including a lip  46   d  which is in the form of a pointed tip.  FIGS. 7A–7C  show an embodiment  56  of the straight head portion, including a lip  46   e  which is in the form of a flat bill shape and which includes a more rounded transition between the sidewalls and the top portion of the outer surface  24 . 
   In another embodiment of the present invention, the head portion may be curved with respect to the longitudinal axis to enable the interior surface of the head portion to impart a deflecting force on the catheter as it is directed through the head portion and beyond the opening therein.  FIGS. 8A–8D  show such an embodiment  60 , wherein  FIG. 8A  is a side view of the head portion  60 ,  FIG. 8B  is a top view of the head portion,  FIG. 8C  is a cross-sectional view of the head portion  60 , taken along line  8 C— 8 C in  FIG. 8B  and  FIG. 8D  is a three-dimensional perspective view of the head portion  60 . As shown in  FIGS. 8A–8D , head portion  60  is generally spoon-shaped, wherein interior surface  62  and the exterior surface  64  are curved upwardly with respect to the longitudinal axis  16 . The combination with sidewalls  66  and interior surface  62  result in a channel  68  that is concave in two-dimension, both along the longitudinal axis  16  and around it. This feature is particularly shown in  FIG. 8D . Similarly to the head portion  18 , head portion  60  tapers from its proximal end  74 , adjacent distal end  20  of tube  12  to the tip  76 . This taper also occurs along outer sidewalls  78  as well as along exterior surface  64  with respect to two orthogonal planes which intersect along the longitudinal axis  16  of tube  12 . Head portion  60  may also include a circumferential shoulder portion  70 , for facilitating the taper described above. In the spoon-shaped configuration shown in  FIGS. 8A–8D , the tip  76  includes a lip  80   a  that is continuous with exterior portion  82  of the head portion  60 . 
   Lumen extension portion  69  of the head portion  60  terminates at an opening  72  of the head portion  60 , which opening  72  enables a catheter passing through the lumen  14  and lumen extension portion  69  to exit the head portion proximate the tip  76  at an angle which is relatively acute with respect to the relative plane within which the opening  72  lies. 
   In use, when the tip  76  of head portion  60  is inserted into the incision and the catheter is directed through lumen  14  into channel  68 , it contacts surface  62  and is deflected laterally with respect to the longitudinal axis  16 . This lateral deflection facilitates navigation of the catheter through the duct by the surgeon by enabling the surgeon to laterally move the catheter within the duct by laterally moving the head portion of the introducer. 
   Shown in  FIGS. 9–11  are various configurations of the lip  80 . Each configuration is advantageous in enabling the surgeon to insert the tip and head portion into the incision in the cystic duct and through the valves and other obstructions in the duct that may be encountered by the surgeon during the procedure.  FIGS. 9A–9C  show an embodiment  84  of the spoon-shaped head portion, including a lip  80   b  which is in the form of a flat bill shape.  FIGS. 10A–10C  show an embodiment  86  of the spoon-shaped head portion, including a lip  80   c  which is in the form of an extended flat bill shape.  FIGS. 11A–11D  show an embodiment  88  of the spoon-shaped head portion, including a lip  80   d  which is in the form of a pointed tip. 
   In yet another embodiment of the present invention, the head portion may be curved with respect to the longitudinal axis to enable the interior surface of the head portion to impart a deflecting force on the catheter as it is directed through the head portion and beyond the opening therein, however, with shallower side walls and a lower profile than the spoon-shaped head portion described above.  FIGS. 12A–12D  show such an embodiment  90 , wherein  FIG. 12A  is a side view of the head portion  90 ,  FIG. 12B  is a top view of the head portion  90 ,  FIG. 12C  is a cross-sectional view of the head portion  90 , taken along line  12 C— 12 C in  FIG. 12B  and  FIGS. 12D and 12E  are three-dimensional perspective views of the head portion  90 . As shown in  FIGS. 12A–12E , head portion  90  is generally scoop-shaped, wherein interior surface  92  and the exterior surface  94  are curved upwardly with respect to the longitudinal axis  16 . The combination of shallow sidewalls  96  and interior surface  92  result in a channel  100  that is concave in two-dimension, both along the longitudinal axis  16  and around it. This feature is particularly shown in  FIGS. 12D and 12E . 
   As shown in  FIGS. 12A–12E , the interior surface  92  and the exterior surface  94  converge toward each other to form a tip  106  which, as described above, is used to facilitate the insertion of the head portion  90  into an incision in the cystic duct. In the embodiment of head portion  90 , channel  100  continuos until tip  106  with no lip between the channel  100  and tip  106 . Lumen extension portion  108  of the head portion  90  terminates at an opening  110  of the head portion  90 , which opening  110  enables a catheter passing through the lumen  14  and lumen extension portion  108  to exit the head portion proximate the tip  106  at an angle which is relatively acute with respect to the average plane within which the opening  110  lies. Similarly to the head portion  18 , head portion  90  tapers from its proximal end  104 , adjacent distal end  20  of tube  12  to the tip  106 . This taper also occurs along outer sidewalls  114  as well as along exterior surface  116 , the optional exception of portion  102 , with respect to two orthogonal planes which intersect along the longitudinal axis  16  of tube  12 . 
     FIGS. 13A–13C  show another embodiment  120  of the scoop-shaped head portion  18 . This embodiment is similar to that shown in  FIGS. 12A–12C , with the exception that the channel  100  terminates at a lip  108   a  of the tip  106 . In this embodiment, lip  108   a  is formed to be continuous with exterior portion  122  of the head portion. 
   Shown in  FIGS. 14–16  are various configurations of the lip  108 . Each configuration is advantageous in enabling the surgeon to insert the tip and head portion into the incision in the cystic duct and through the valves and other obstructions in the duct that may be encountered by the surgeon during the procedure.  FIGS. 14A–14C  show an embodiment  124  of the scoop-shaped head portion, including a lip  108   b  which is in the form of a flat extended bill shape.  FIGS. 15A–15C  show an embodiment  126  of the scoop-shaped head portion, including a lip  108   c  which is in the form of an short flat bill shape.  FIGS. 16A–16C  show an embodiment  128  of the scoop-shaped head portion, including a lip  108   d  which is in the form of a pointed tip. 
   The head portion may be constructed such that the angle at which the catheter may exit the opening can vary from between approximately zero degrees, relative to the longitudinal axis, as shown in the embodiments of  FIGS. 1–7 , or at any angle up to approximately 90 degrees. With respect to the spoon and scoop-shaped head portions, the preferable range of the angle of exit of the catheter with respect to the longitudinal axis is approximately zero to approximately sixty degrees, and more preferably, between approximately zero and approximately thirty degrees. 
   The straight head, spoon-shaped head and scoop-shaped shaped head each have a suitably small profile. Preferably the straight head and spoon-shaped head portions are constructed such that they remain within planes which are tangent to the exterior surface of the tube  12 . The smaller profile design of the protrusion allows insertion through the incision in the cystic duct, and placement within it. Following such insertion of the tip of the head portion, a catheter may be inserted into the introducer from the proximal end, and extended out from the opening in the head portion, and is guided into the lumen of the cystic duct. The curved, spoon-shaped and scoop-shaped designs of the head portion also provide lateral and longitudinal support for the catheter if it encounters resistance from valves or other obstructions. 
   The small profile design of the protrusion also makes it easier for the introducer to be inserted along the lumen of the cystic duct. During an operation, electro-cauterization may be utilized to stop any bleeding at the incision site, which may cause the duct tissue to shrink, or cause a buildup of dead tissue to obstruct the lumen of the cystic duct. The leading edge of the tip can be used to pass through this narrowed incision, and then can be positioned for navigating the catheter through the duct. 
   Referring to  FIG. 17  and  FIG. 18 , which are top and side perspective views, respectively, of the insertion of the catheter introducer of the present invention into a cystic duct during an operation, the catheter introducer  10  is inserted by a surgeon through a trocar into a patient&#39;s abdomen. The introducer  10  is guided towards a transverse incision  138  in the cystic duct  140 . In the case of the straight head portion, the head portion is then inserted into the incision in the duct, and positioned so that the longitudinal axis  16  of the tube generally lines up with the longitudinal axis of the duct, such that the catheter can be directed through the lumen and out of the straight head portion into the duct. In the case of the curved spoon and scoop-shaped head portions, the head portion is inserted into the incision in the duct, and positioned so that the concave channel is substantially perpendicular to the longitudinal axis of the duct. The catheter is then advanced through the introducer  10  until it extends to the concave channel and is then deflected laterally out of the opening in the head portion and is guided into the lumen of the duct substantially in line with the longitudinal axis of the duct. As described above, the positioning of the introducer  10  in the cystic duct provides good lateral and longitudinal support for the catheter if it encounters resistance from valves or other obstructions. 
   While the preferred embodiments and method of use of the invention have been illustrated and described in some detail in the drawings and foregoing description, it should be understood that this description is made only by way of example to set forth the best mode contemplated of carrying out the invention and not as a limitation to the scope of the invention which is pointed out by the claims below.