Abstract:
A steerable catheter device which can be steered to locations within the epidural space, as well as methods of use and manufacture are disclosed. The steerable catheter provides a site-specific drug delivery system for accessing the epidural space. The catheter devices includes a steerable wire or a liner extending from a proximal end of the catheter to the catheter&#39;s distal end. Forces applied to the wire or the liner cause the distal end to deflect and/or rotate to reach a targeted epidural site.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This is a non-provisional and claims benefit to U.S. Provisional Application No. 61/397,943 entitled “Steerable Catheter Device and Uses Thereof” filed on Jun. 18, 2010, and U.S. Provisional Application No. 61/455,199 entitled “Steerable Epidural Catheter” filed on Oct. 15, 2010, both of which are hereby incorporated by reference. 
     
    
     FIELD 
       [0002]    The present application relates to surgical devices and more particularly to a steerable catheter that can be guided to site-specific locations. 
       BACKGROUND 
       [0003]    The most common interventional pain management procedures are used to manage chronic neck and/or back pain, as well as pain associated with labor and delivery. These procedures typically involve epidural injections to deliver pain reducing medicines to the epidural space. Epidural injections may be made using a direct needle injection at the site of pain (transforaminal approach) or using a catheter maneuvered into the epidural space (interlaminar approach). Although, the transforaminal approach may be more diagnostic and provide greater long term pain management than the interlaminar approach, it carries an increased risk of complications, such as inadvertent vascular or nerve injury, spinal cord injury and death. 
         [0004]    Guided catheters have been employed to manage pain using the interlaminar approach. These types of catheters are typically designed for intravascular areas and are not optimized for epidural procedures. Vascular-type guided catheters often rely on the use of a guide wire to position the catheter within the vascular system. After positioning the guide wire near the treatment site, a separate, hollow catheter may then be threaded over the guide wire and maneuvered to the desired location. The guide wire is then withdrawn and the catheter left in place. After the procedure is completed, the guide wire must be re-inserted into the inner lumen of the catheter and the catheter and guide wire collectively withdrawn. However, this process can be cumbersome, time-consuming, and potentially increase the risk of injury to the patient. 
       SUMMARY 
       [0005]    In one embodiment, a steerable catheter device may include an elongated catheter body defining a proximal portion and a distal portion and a lumen formed along the elongated catheter body. The lumen defines a proximal end and a distal end with a reinforcing coil disposed within the lumen for supporting the elongated catheter body. A steerable wire extends proximate or within the lumen from the proximal end of the lumen to a distal tip defined at the distal end of the elongated catheter body, wherein the steerable wire is affixed to the distal tip. Actuation of the steerable wire at the proximal end of the elongated catheter body causes at least one of a rotation and a deflection of the distal tip. 
         [0006]    In another embodiment, a steerable catheter device may include an elongated catheter body defining a proximal portion and a distal portion and a lumen formed along the elongated catheter body. The lumen defines a proximal end and a distal end with a reinforcing coil disposed within the lumen for supporting the elongated catheter body. A steerable liner extends proximate or within the lumen from the proximal end of the lumen to a distal tip defined at the distal end of the elongated catheter body, wherein the steerable liner is affixed to the distal tip. Actuation of the steerable liner at the proximal end of the elongated catheter body causes at least one of a rotation and a deflection of the distal tip. 
         [0007]    In yet another embodiment, a method for delivering a drug to an epidural space may include:
       accessing an area adjacent to the epidural space using a steerable catheter comprising:
           an elongated catheter body defining a proximal portion and a distal portion and a lumen along the elongated catheter body, the lumen having a proximal end and a distal end with a reinforcing coil disposed within the lumen for supporting the elongated catheter body, the lumen containing a steerable wire extending proximate or within the lumen from the proximal end of the lumen to a distal tip defined at the distal end of the elongated catheter body, wherein the steerable wire is affixed to the distal tip, wherein actuation of the steerable wire at the proximal end of the elongated catheter body causes at least one of a rotation and a deflection of the distal tip;   
           applying a force to the steering mechanism to at least one of a deflection and a rotation of the distal end into the epidural space;   providing a liquid through the lumen of the catheter;   transmitting the liquid from the proximal end of the lumen to the distal end of the lumen positioned within the epidural space; and   removing the elongated catheter body.       
 
         [0014]    In an embodiment, a method for manufacturing a steerable catheter device may include:
       forming an elongated catheter body defining a distal portion and a proximal portion, the elongated catheter body defining a lumen having a proximal end and a distal end, wherein the distal portion of the elongated catheter body defining a distal tip; and   inserting a steerable wire along the lumen from the proximal portion of the elongated catheter body to the distal tip, wherein actuating the steerable wire causes at least one of a rotation and a deflection of the distal tip; and   affixing an end of the steerable wire to the distal tip.       
 
         [0018]    In another embodiment, a method for manufacturing a steerable catheter device may include:
       forming an elongated catheter body defining a distal portion and a proximal portion, the elongated catheter body defining a lumen having a proximal end and a distal end, wherein the distal portion of the elongated body defining a distal tip; and   inserting a steerable wire along the lumen from the proximal portion of the elongated catheter body to the distal tip, wherein actuating the steerable wire causes at least one of a rotation and a deflection of the distal tip; and   affixing an end of the steerable line to the distal tip.       
 
         [0022]    Additional objectives, advantages, and novel features will be set forth in the description which follows or will become apparent to those skilled in the art upon examination of the drawings and detailed description which follows. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]      FIG. 1  is an illustration of a prior art epidural site treatment system; 
           [0024]      FIG. 2  is a partial cross-sectional side view showing one embodiment of a steerable catheter; 
           [0025]      FIG. 3  is a side view illustrating the distal end of the steerable catheter; 
           [0026]      FIGS. 4A and 4B  are side views the deflection action of the steerable catheter; 
           [0027]      FIG. 5  is a side view showing the collar of the steerable catheter; 
           [0028]      FIG. 6  is a side view of another embodiment of the steerable catheter engaged to a steering mechanism; 
           [0029]      FIG. 7  is a view of a steering mechanism of the steerable catheter; and 
           [0030]      FIG. 8  is a cross-sectional view of tension device of the steerable catheter. 
       
    
    
       [0031]    Corresponding reference characters indicate corresponding elements among the view of the drawings. The headings used in the figures should not be interpreted to limit the scope of the claims. 
       DETAILED DESCRIPTION 
       [0032]    Aspects of the present disclosure include devices and methods for a steerable catheter. In particular, the steerable catheter includes a steerable wire or a bent liner incorporated proximate or within the lumen of the steerable catheter to maneuver the steerable catheter by deflection and/or rotation of the distal tip defined at a distal end of the steerable catheter. The steerable catheter functions without a removable guide wire for positioning and removing the steerable catheter 
         [0033]    Referring to the drawings, a prior art system  10  to access an epidural site  12  of a mammalian body is illustrated and generally indicated as  10  in  FIG. 1 . The prior art system  10  includes an epidural needle  14  that is used to puncture the skin and access the epidural treatment site  12 . A guide wire (not shown) and a catheter  16  are collectively inserted through the lumen of the needle  14  which deploys the catheter  16  at the treatment site  12 . However, the use of the guide wire to maneuver the catheter  16  through the needle  14  can increase the risk of injury to surrounding tissue and may also require additional equipment to properly manipulate the guide wire and catheter  16 . 
         [0034]    Referring to  FIG. 2 , one embodiment of a steerable catheter generally indicated as  100  is illustrated which overcomes the issues related to the prior art system  10 . The steerable catheter  100  includes an elongated catheter body  102  having a proximal portion  109  defining an opening  107  and a distal portion  111  defining a distal tip  108 . In addition, the opening  107  is in fluid flow communication with a lumen  104  (shown in phantom lines) that extends longitudinally along the elongated catheter body  102 . In addition, the lumen  104  has a proximal end  112  in communication with the opening  107  and a distal end  110  that communicates with the distal tip  108 . The elongated catheter body  102  may have a diameter between in 1 mm and 5 mm. In one embodiment, the elongated body  102  has a diameter equal to or less than 1.5 mm. 
         [0035]    A steerable wire  106  may be disposed within the lumen  104  having a proximal end  130  that extends outwardly from the opening  107  and a distal end  132  that is positioned proximate or within the distal tip  108 . In one embodiment, the steerable wire  106  may be manipulated to deflect and/or rotate the distal tip  108  of the elongated catheter body  102  as shall be discussed in greater detail below. In other embodiments, the steerable wire  106  may be made from a malleable metal material, a bendable plastic material, or a metal material having memory retention characteristics. As shown, the steerable wire  106  may extend from the distal end  110  to a proximal end  112  of the elongated catheter body  102  in parallel orientation relative to the longitudinal axis  700  of the elongated catheter body  102 . The lumen  104  also provides fluid flow communication between the proximal end  112  and distal end  110  of the elongated catheter body  102  such that a medicinal or therapeutic agent, for example a pharmaceutical drug, may be injected at the proximal end  112  and then discharged at the distal end  110  of the lumen  104 . In some embodiments, a reinforced coil  114  may be disposed along a portion or entire length of the lumen  104  to provide a reinforcing structure to the elongated catheter body  102 . In one embodiment, the steerable wire  106  may be disposed longitudinally through the reinforcing coil  114 ; however, in other embodiments, the steerable wire  106  may be disposed freely within the lumen  104 , attached along the inner surface  113  of the lumen  104  or embedded under the inner surface  113  within the elongated catheter body  102 . The reinforcing coil  114  also serves to structurally connect the distal tip  108  with distal portion  132  of the elongated catheter body  102 . In one embodiment, the reinforcing coil  114  may be a variable tension coiled spring. In other embodiments, the reinforcing coil  114  may be a woven, helical, or braided reinforcement structure within the elongated catheter body  102 . 
         [0036]    As further shown, the distal tip  108  includes a plurality of holes  116  that are in fluid flow communication with the lumen  104  such that a liquid, for example a therapeutic agent, injected through the opening  107  of the lumen  104  may pass through the plurality of holes  116  and into the epidural space or other body cavity. The plurality of holes  116  also reduces the probability of any debris or obstruction from completely preventing fluid flow communication through the plurality of holes  116 . In some embodiments, the distal tip  108  may be rounded and have a generally hemispherical configuration. This generally hemispherical configuration of the distal tip  108  also minimizes injuries to the tissue at and around the epidural site  12 . 
         [0037]    As noted above, the proximal end  130  of the steerable wire  106  may be manually manipulated to cause the distal tip  108  to rotate and/or deflect away relative to a longitudinal axis  700  of the elongated catheter body  102 . In particular, distal tip  108  may be deflected such that a center axis  702  of the distal tip  108  is deflected at an angle  704  relative to the longitudinal axis  700 . In some embodiments, the angle  704  of deflection may be between zero to ninety degrees, although in some embodiments the angle  704  of deflection may be between twenty to forty five degrees. The manipulation of the steerable wire  106  may include the application of a tensile force, a compressive force, a rotational torque, or a force perpendicular applied along the longitudinal axis  700 . 
         [0038]    In various aspects, a combination of manipulative forces may be used to manipulate the steerable wire  106 . For example, a first force may deflect the center axis  702  of distal tip  108  from the longitudinal axis  700  at a deflection angle  704  and a second force, such as a rotational force may be applied to rotate the distal tip  108  about the center axis  702 . In some embodiments, the first and second forces may be applied sequentially or concurrently to deflect and rotate the distal tip  108 . 
         [0039]    Referring to  FIG. 3 , the steerable catheter  100  may include a reinforcing coil  114  defining a structural defect  118 . For example, the structural defect  118  may be generally a wedge-shaped formation defined by one or more loops of the reinforcing coil  114 , which may be formed by the intentional strengthening of one or more loops of the reinforcing coil, or the fusion of two or more loops of the reinforcing coil  114 . The structural defect  118  facilitates the deflection and/or rotation of the distal tip  108  when the steerable wire  106  is manipulated. In one aspect, the structural defect  118  reduces the strength of the reinforcing coil  114  at the formation of the structural defect  118  along the reinforcing coil  114 , and therefore makes the elongated catheter body  102  more flexible at the distal portion  111  and susceptible to the rotation and/or deflection caused by manipulation of the steerable wire  206 . Although the structural defect  118  may be wedge-shaped, the structural defect  118  may have other shapes, such as a symmetrical shape, an asymmetrical shape, a rectangular shape, a square shape or combination of above shapes. 
         [0040]    Referring to  FIGS. 4A and 4B , the steerable catheter, designated  200 , has substantially the same configuration as the steerable catheter  100  having an elongated catheter body  202  that defines a lumen  204  having a reinforcing coil  214  and a steerable wire  206  disposed longitudinally proximate or within the lumen  204 . The lumen  204  is in fluid flow communication with a plurality of holes  208  and extends substantially along longitudinal axis  700  when the distal portion  211  is in a straight configuration. In this particular embodiment, the elongated catheter body  202  defines a structural defect  218  for facilitating the deflection and/or rotation of the distal tip  208  rather than the reinforcing coil  214  having the structural defect. In some embodiments, the structural defect  218  may have a wedge-shape configuration defined along the elongated catheter body  202 , one or more pleats incorporated into the elongated catheter body, or the structural defect  218  may constitute the partial removal of a localized portion of the external or internal surface of the elongated catheter body  202 . In one aspect, the structural defect  218  reduces the strength of the elongated catheter body  302  at the location of the structural defect  218 , and therefore makes the distal portion  211  of the elongated catheter body  202  more flexible and susceptible to the rotation and/or deflection caused by manipulation of the steerable wire  206 . As shown in  FIG. 4A , manipulation of the steerable wire  206  causes center axis  702  of the distal tip  208  to deflect at an angle  705  relative to the longitudinal axis  700 , thereby bringing the opposing sides  218 A and  218 B of the structural defect  218  toward each other. Referring to  FIG. 4B , further manipulation of the steerable wire  206  causes an increase in the deflection angle  706  between the center axis  702  and the longitudinal axis  700  and brings the opposing sides  218 A and  218 B of the structural defect  218  closer together to facilitate the deflection of the distal tip  208 . 
         [0041]    Referring now to  FIG. 5 , another embodiment of the steerable catheter, designated  300 , is illustrated. In this embodiment, the steerable catheter  300  includes an elongated catheter body  302  defining a lumen  304  configured to receive a steerable liner  306  therein. The steerable liner  306  defines a proximal portion  312  and a distal portion  314  that extends substantially the length of the elongated catheter body  302  such that manipulation of the proximal portion  312  of the steerable liner  306  causes the distal portion  314  to deflect and/or rotate the distal tip  308 . The steerable liner  306  is a substantially rigid tubular structure, such as a hollow stylette, having a diameter less than the diameter of the lumen  304 . The steerable liner  306  has a generally angled configuration, where the distal portion  314  of the steerable liner  306  may be angled relative to the proximal end  312  of the steerable liner  306 . In some embodiments, the distal portion  314  of the steerable liner  306  may be angled in a range between zero degrees to ninety degrees relative to the longitudinal axis  700 . In one aspect, the steerable liner  306  is threaded through the lumen  304  of the elongated catheter body  302 , such that the center axis  707  of distal tip  308  of the elongated catheter body  302  is deflected from the longitudinal axis  700  by an angle  709  that is substantially equal to the deflection of the distal portion  314  of the steerable liner  306 . In some embodiments, the steerable catheter  300  may also include a steering collar  320  engaged to the proximal portion  312  of the steerable liner  302  to articulate the distal portion  314  of the steerable liner  306 . In one embodiment, the steering collar  320  is mechanically engaged with the steerable liner  306  to impart a force upon the steerable liner  306 . The steerable liner  306  may be subjected to tensile force, a compressive force, a rotational torque, or a perpendicular force along the longitudinal axis  700  of the steerable catheter  300 . 
         [0042]    Referring now to  FIGS. 6-8 , the steerable catheter  100  may be operatively engaged to a steering mechanism, generally indicated as  400 , for articulating the steering wire  106 . In particular, operation of the steering mechanism  400  imparts a force that manipulates the steerable wire  106  and causes the deflection and/or rotation of the distal tip  108  as described above. The steering mechanism  400  may include a tension device  402  and a rotational steering device  404 . The tension device  402  may be used to impart and maintain constant tensile and compressive forces on the steerable wire  106 , while the rotational steering device  404  is used to impart a rotational force on the steerable wire  106 . In one aspect, the functionality of the tension device  402  and a rotational steering device  404  may be incorporated into single steering device that manipulates the steerable wire  106 . 
         [0043]    As shown in  FIG. 8 , the tension device  402  may also incorporate locking features  406  to maintain a constant force to the steerable wire  106 . Referring to  FIGS. 7 and 8 , the steering mechanism  400  may include a plurality of ratchet teeth  408  that are mechanically engaged to locking features  406  of the tension device  402  to prevent undesired motion of the tension device. For example, the locking features  406  may be a series of pawls or other projections to slidably engage with the plurality of ratchet teeth  408  and prevent undesired retrograde motion of the tension device  402 . 
         [0044]    In various other embodiments, the steering mechanism  400  may also include an injection port,  410  and a handle  412 . The injection port  410  may used to deliver medications to the epidural site  12  through the lumen  104  of the elongated catheter body  102 , while the handle  412  provides a means to operate the steering mechanism  400 . The steering mechanism  400  may include a plurality of ratchet teeth  404  that are mechanically engaged by the tension device  402  to prevent undesired motion of the steering mechanism  400  and the steerable wire  106 . In another embodiment, the steering mechanism  400  may mechanically engaged to the steerable catheter  100 . The steering mechanism  400  may be used to impart and maintain constant tensile and compressive forces on the steerable liner  406  through the tension device  402  and the rotational steering device  404 . 
         [0045]    It is believed that the present disclosure and many of its attendant advantages will be understood by the foregoing description, and it will be apparent that various changes may be made in the form, construction, and arrangement of the components without departing from the disclosed subject matter or without sacrificing all of its material advantages. The form described is merely explanatory, and it is the intention of the following claims to encompass and include such changes. 
         [0046]    While the present disclosure has been described with reference to various embodiments, it will be understood that these embodiments are illustrative and that the scope of the disclosure is not limited to them. Many variations, modifications, additions, and improvements are possible. More generally, embodiments in accordance with the present disclosure have been described in the context of particular implementations. Functionality may be separated or combined in blocks differently in various embodiments of the disclosure or described with different terminology. These and other variations, modifications, additions, and improvements may fall within the scope of the disclosure as defined in the claims that follow. 
         [0047]    Those skilled in the art will appreciate that variations from the specific embodiments disclosed above are contemplated by the invention. The following invention should not be restricted to the above embodiments, but should be measured by the following claims.