Patent Publication Number: US-2020282181-A1

Title: Steering tool

Description:
CROSS-REFERENCE TO PRIOR APPLICATIONS 
     This application is a continuation of and claims priority from U.S. patent application Ser. No. 14/044,886, filed 3 Oct. 2013. 
    
    
     FIELD OF THE INVENTION 
     The present invention generally relates to a steering tool for steering medical devices through body lumens. 
     BACKGROUND OF THE INVENTION 
     PCT Patent Application PCT/US2013/040691, to the present inventor, describes a steering tool for steering medical devices through body lumens. The steering tool has an internal tube disposed inside an external tube. The internal and external tubes are arranged for longitudinal axial movement relative to one another. The distal end of the internal tube is fixedly joined to the distal end of the external tube. One or both of the internal and external tubes is slotted near the distal end thereof. The longitudinal axial movement causes bending of the distal ends of the tubes. One or both of the internal and external tubes are slotted near the distal ends thereof. The steering tool provides a distal tip which combines steerability, flexibility and torqueability. The tool eliminates the need for pull/push wires. 
     Some of the advantages of that steering tool include reduced cross section, circular cross section in each direction for uniform stability of bending in different directions (towards two or more sides), very thin wall thickness, and applicability to very small tubes (e.g., diameters of 0.2-3 mm). The steering tool also works well with larger tubes. The steering tool simplifies production and reduces the number of parts for any steerable endoscope in medical and industrial fields. 
     SUMMARY OF THE INVENTION 
     The present invention seeks to provide further improvements to the steering tool for steering medical devices through body lumens, as is described more in detail hereinbelow. 
     There is thus provided in accordance with an embodiment of the present invention a steering tool including an internal tube disposed inside an external tube, the internal and external tubes being arranged for longitudinal axial movement relative to one another, wherein a distal end of the internal tube is fixedly joined to a distal end of the external tube, and at least one of the internal and external tubes is slotted near the distal end thereof, and wherein the longitudinal axial movement causes bending of the distal ends of the tubes. 
     In accordance with an embodiment of the present invention both of the internal and external tubes are slotted near the distal ends thereof. 
     In accordance with an embodiment of the present invention shapes of the slots change as a parameter of distance from the distal ends of the internal and external tubes. 
     In accordance with an embodiment of the present invention the internal and external tubes are each formed with one or more alignment holes for correct axial and rotational alignment of the internal and external tubes during joining and assembly. 
     In accordance with an embodiment of the present invention an alignment pin is inserted in the one or more alignment holes. 
     In accordance with an embodiment of the present invention an open-ended axial slot is formed in at least one of the internal and external tubes. The axial slot may be open to the most distal slot of the transverse slots. 
     In accordance with an embodiment of the present invention the transverse slots decrease in length and width with increased distance from the distal ends of the internal and external tubes. 
     The slots limit the amount of possible tube bending to avoid damage to the tubes. For example, the outer slots protect while pushing and the internal slots protect while pulling the internal tube. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will be understood and appreciated more fully from the following detailed description taken in conjunction with the drawings in which: 
         FIG. 1  is a simplified illustration of a steering tool, in accordance with a non-limiting embodiment of the present invention, showing one of the tubes of the steering tool in a spread-out view; 
         FIG. 2  is a simplified illustration of the steering tool, in accordance with a non-limiting embodiment of the present invention, showing internal and external tubes which are slotted; 
         FIG. 3  is a simplified illustration of the steering tool, showing an alignment pin for proper alignment of the tubes during assembly; 
         FIG. 4  is a simplified illustration of the steering tool with the internal part being a hollow tube with no slots or a conduit for fluid or wires for energy delivery or optic fiber to transfer optic data or laser; and 
         FIGS. 5A and 5B  are simplified pictorial and cutaway illustrations, respectively, of a steering tool with a manipulation handle, constructed and operative in accordance with a non-limiting embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Reference is now made to  FIGS. 2 and 3 , which illustrate a steering tool  10 , in accordance with a non-limiting embodiment of the present invention. 
     Steering tool  10  includes an internal tube  12  disposed inside an external tube  14 . A distal end  12 D of internal tube  12  is fixedly joined to a distal end  14 D of external tube  14 . The term “joined” encompasses any method for attaching the materials of the tubes together, such as but not limited to, welding, ultrasonic welding, thermal bonding, adhesive bonding, molding, and others. The internal and external tubes  12  and  14  are arranged for longitudinal axial movement relative to one another (except for their distal ends which are joined together). 
     In accordance with an embodiment of the present invention, internal tube  12  and external tube  14  are each formed with one or more alignment holes  13  for correct alignment (including axial and rotational alignment about the longitudinal axis) of the tubes during joining and assembly. An alignment pin  15  ( FIG. 3 ) may be inserted in alignment holes  13  to hold the tubes in the proper alignment during joining. The alignment holes  13  may be off-center and/or of two different diameters to ensure that the tubes are not accidentally aligned incorrectly. 
     The outer diameter of internal tube  12  is smaller than the inner diameter of external tube  14  so they can easily slide relative to each other. This difference in diameter may pose a problem during welding or other types of joining. In accordance with an embodiment of the present invention, in order to achieve good joining (e.g., welding or bonding) between the tubes despite the difference in diameters, an open-ended axial slot  17  is formed in internal tube  12  and/or external tube  14 . Slot  17  provides a path for welding, soldering or adhesive material to flow and join the tubes together. 
     Internal and external tubes  12  and  14  may be made of any suitably flexible, medically safe material, such as but not limited to, stainless steel (e.g., AISI 316), nitinol, cobalt-chromium alloy, nickel-titanium alloy, and others, glass fibers, plastics (e.g., nylon, polypropylene, and many others) or combinations thereof. As will be described further below, the tubes can be used for applications involving light guides, lasers, optic or electrical transfer and other uses, in addition to the mechanical function of bending. 
     At least one of the internal and external tubes  12  and  14  is slotted with slots  16  near the distal end thereof (e.g., transverse to the longitudinal axis of the tubes; the term transverse encompassing any angle—not just perpendicular—which is not parallel to the longitudinal axis of the tubes). In the preferred embodiment both tubes are slotted, but alternatively only one of the internal and external tubes is slotted and the other may be flexible but not slotted. The longitudinal axial movement causes bending of the distal ends of the tubes (on account of them being joined together), as is known from PCT/US2013/040691. One of the internal and external tubes can be longer than the other (e.g., the internal one is longer for grasping its proximal end for pushing and pulling thereof). 
     Slots  16  increase the flexibility toward the distal end of the tube or tubes for steerability of the device and controlled manipulation thereof. The amount of flexibility can be controlled by the number of slots, spacing therebetween, shape of the slot, angle subtended by the slot, thickness of the tube, material of the tube, and other factors. Slots  16  may subtend an arc of about 180-270°. 
     For example, as seen in  FIG. 1 , the shapes of slots  16  change as a parameter of distance from the distal end. In the illustrated example, the slots decrease in length and width (e.g., asymptotically to a minimum size) with increased distance from the distal end. In this manner, the bending radius remains basically constant at any distance from the distal end and the bending moment increases with increased distance from the distal end. Axial slot  17  may be open to the most distal slot  16 . 
     The steering tool  10  may be covered with a semi-rigid or flexible sheath  18  (shown partially in broken lines in  FIG. 2 ) and used as a catheter or needle. In a more preferred embodiment, shown in  FIG. 4 , the internal tube  12  is a simple tube or wire with no slots. In the case of a hollow tube, the internal tube  12  can serve as the conduit for delivery of fluids, light, laser, optic, cameras, illumination, electrical energy transfer (e.g., wired connections), and others, in addition to the mechanical function of bending, Thus, the device can be used to deliver fluids to places in a body with high accuracy, such as but not limited to, direct injection of drugs into the brain. For example, tool  10  may be used as a needle to protrude through or into a blood vessel and inject substances directly into the brain, tumor or infected area. The steering tool  10  may be used as a catheter to direct and deliver cooled gas to freeze tumors or other areas. The steering tool  10  may be used as a catheter to guide fiber optic or laser devices for illumination, treatment, ablation or drying or other uses. In another embodiment, the fiber optic can be part of the mechanical steering system, serving as a pull wire inside the internal or external tube. In this manner, a controlled fiber optic with a diameter of 0.3 mm becomes feasible. 
     In any of the embodiments, the distal edge shape of the internal tube, external tube and/or overall tool may be not only circular, but also shaped as an electrode, needle or other shapes. 
     Reference is now made to  FIGS. 5A and 5B , which illustrate a steering tool with a manipulation handle  20 , constructed and operative in accordance with a non-limiting embodiment of the present invention. 
     In this steering tool, the proximal end  19  of the external tube  14  is affixed or locked in an external tube holder  22  at the distal end of the handle  20 . The internal tube  12  is disposed in external tube  14  as described above. The internal tube  12  extends through the length of handle  20 , and a proximal portion  23  of internal tube  12  may be held by a proximal internal tube holder  24 . The internal tube holder  24  may include a septum  26  which may be used to seal passage of the internal tube  12  therethrough. The handle  20  may be provided with a proximal fluid connector  28 . 
     The handle  20  is provided with a tube manipulator  30 , such as a linear slider, for causing relative axial movement of the internal and external tubes. For example, the tube manipulator  30  may abut against or be connected to a movable portion  32  of handle  20 , which is connected to or abuts against the external tube holder  22 . By moving tube manipulator  30  distally, the movable portion  32  also moves distally and causes the internal tube  12  to move distally as well, thereby causing bending of the distal tip of the internal and external tubes, as described above. The tube manipulator  30  may abut proximally against a stationary portion of the handle  20  and/or may “click” into a groove formed in the handle, which serves as a proximal stop and locks the tube manipulator  30  in place. The tube manipulator  30  may be released when desired from the locked position and relocked in place. Thus, the steering tool can be used very easily as a guide wire for guiding catheters and other devices.