Abstract:
A neuro-surgery assembly includes a neuro-catheter slidably received over a wire guide. The wire guide includes an inner tube positioned within an elongate hollow tube that includes a pattern of openings at its distal segment to provide an atraumatic tip for reaching sensitive locations in a brain. The wire guide is changeable between a stiff condition in which the inner tube is pressurized and a soft condition in which the inner tube is depressurized. The user may switch between the stiff and soft conditions to negotiate the tortuous pathway to a brain treatment site without a need to swap out to a different wire guide to support advancement of the neuro-catheter.

Description:
TECHNICAL FIELD 
       [0001]    The present disclosure relates generally to neuro-surgery, and more particularly to a wire guide changeable at will between stiff and soft conditions. 
       BACKGROUND 
       [0002]    Some neuro-surgery treatments require that a distal end of a neuro-catheter be positioned in close proximity to a treatment site in a brain. Prior to the neuro-catheter reaching the treatment site, a wire guide must often first be properly positioned in proximity to the treatment site. Due to the tiny size and sensitivity of passageways within the brain, very soft wire guides must often be used to navigate the tortuous pathway to the treatment site. However, these extremely soft and slender wire guides may not be stiff enough to support the neuro-catheter when being slid over the wire guide to the treatment site. Thus, the physician may often have to repeatedly switch between relatively soft and stiff wire guides to successfully negotiate each of several sharp turns on the way to the treatment site. This switching back and forth between different wire guides can extend the duration of the surgery, increase risks to patients and increase medical device costs. 
         [0003]    The present disclosure is directed toward overcoming one or more of the problems set forth above. 
       SUMMARY 
       [0004]    In one aspect, a wire guide includes an inner tube with a closed distal end positioned inside an elongate hollow tube with a distal segment that defines a plurality of openings. The openings are arranged in a pattern so that a distal segment of the elongate hollow tube is more flexible that a proximal segment. An inflation device with a reservoir of liquid is fluidly connected to a proximal end of the inner tube. The wire guide has a stiff condition in which the inner tube is pressurized by the liquid causing an external surface of the inner tube to bear against an internal surface of the elongate hollow tube. The wire guide has a soft condition in which the inner tube is de-pressurized causing the external surface of the inner tube to be at least partially out of contact with the internal surface of the elongate hollow tube. The inner tube protrudes into a portion, which is less than all, of the plurality of openings when the distal segment is in a curved configuration and the wire guide is in the stiff condition. A shape of each of the plurality of openings changes responsive to flexure of the distal segment away from a straight configuration. 
         [0005]    In another aspect, a neuro-surgery assembly includes a neuro-catheter slidably received over the wire guide. The neuro-surgery assembly has an approach arrangement in which the wire guide is in the stiff condition and a distal end of the neuro-catheter is located proximal to the distal segment. The neuro-surgery assembly as an arrival arrangement in which the wire guide is in the stiff condition and the distal segment of the wire guide is inside the neuro-catheter. The neuro-surgery assembly has a pre-treatment arrangement in which the wire guide is in the soft condition, and the distal segment is withdrawn into the neuro-catheter and separated from the distal end by a withdrawal distance. 
         [0006]    The neuro-surgery assembly may be operated by advancing the wire guide around a turn of a tortuous pathway toward a treatment site in a brain while the wire guide is in the soft condition. The wire guide may then be stopped in the turn with the distal segment in a curved configuration. The neuro-catheter is then slid over the wire guide toward the turn. The wire guide is changed from the soft condition to the stiff condition when a distal end of the neuro-catheter is proximal to the distal segment. The neuro-catheter is then slid around the turn and over the distal segment toward the treatment site. The wire guide is then changed from a stiff condition back to the soft condition. The neuro-catheter is stopped at the treatment site and maintained at the treatment site while the wire guide is withdrawn in the soft condition from the neuro-catheter. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is a perspective schematic view of a neuro-surgery process using the neuro-surgery assembly of the present disclosure; 
           [0008]      FIG. 2  is a schematic view of a neuro-surgery assembly according to the present disclosure; 
           [0009]      FIG. 3  shows a distal portion of the wire guide of  FIG. 2  in a soft condition and a straight configuration; 
           [0010]      FIG. 4  is a side view of the wire guide of  FIG. 3  in the stiff condition and the curved configuration; 
           [0011]      FIG. 5  is a sectioned view of the wire guide of  FIG. 4  as viewed along section lines  5 - 5 . 
           [0012]      FIG. 6  is a schematic view a terminal segment of a tortuous pathway to a treatment site; 
           [0013]      FIG. 7  is the terminal segment of  FIG. 6  after the neuro-catheter and wire guide of the present disclosure prepare for a final turn prior to the treatment site; 
           [0014]      FIG. 8  is the terminal segment of  FIG. 6  after the wire guide has arrived at the treatment site; 
           [0015]      FIG. 9  is the terminal segment with the neuro-surgery assembly in an approach arrangement with the wire guide in the stiff condition; 
           [0016]      FIG. 10  is a view of the terminal segment in an arrival arrangement; and 
           [0017]      FIG. 11  is a view of the terminal segment with the neuro-surgery assembly in a pre-treatment arrangement with the wire guide being withdrawn in a soft condition. 
       
    
    
     DETAILED DESCRIPTION 
       [0018]    Referring initially to  FIGS. 1-5 , a neuro-surgery assembly  10  includes a neuro-catheter  20  (less than or equal to 3 French) slidably received over a wire guide  30 . The neuro-catheter includes a distal end  21  and terminates at its proximal end with a fitting  22 , which may be my suitable fitting known in the art. The wire guide  30  includes an elongate hollow tube  40  with a distal segment  41  that defines a plurality of openings  43  arranged in a pattern  44  so that the distal segment  41  is more flexible than a proximal segment  42  of the elongate hollow tube  40 . An inner tube  50  is positioned inside the elongate hollow tube  40 , and has a closed distal end  51 . An inflation device  60  has a reservoir  61  of liquid  62  fluidly connected to a proximal end  52  of the inner tube  50 . The wire guide  30  has a stiff condition  31  in which the inner tube  50  is pressurized by the liquid  62  causing an external surface  55  of the inner tube  50  to bear against an internal surface  45  of the elongate hollow tube  40 . Liquid  62  may be saline, and may include a radiopaque additive. The wire guide can be changed from the stiff condition  31  ( FIG. 4 ) to a soft condition  32  ( FIG. 3 ) in which the inner tube  50  is depressurized causing the external surface  55  of the inner tube  50  to be at least partially out of contact with the internal surface  45  of the elongate hollow tube  40 . Elongate hollow tube  40  may be made from any suitable material known in the art, including plastics or even metal alloys. The inner tube  50  may be made from a suitable polymer. Although not necessary, the neuro-surgery assembly  10  may include a fitting  70  with a pressure gauge  71  to indicate the pressure of liquid  62  at any given time. The proximal end  52  may include a fitting  53  for fluid connection to inflation device  60  in any suitable manner known in the art. 
         [0019]    As best shown in  FIG. 4 , the inner tube  50  protrudes into a portion  46 , which is less than all, of the plurality of openings  43  when the distal segment  41  is in a curved configuration  33  and the wire guide  30  is in the stiff condition  31 . Thus, those skilled in the art will appreciate that a shape  48  of each of the plurality of openings  43  changes responsive to flexure of the distal segment  41  away from the straight configuration  34 . Thus, one could expect the portion of the openings  46  on the outer radius  35  to enlarge in width while a shape  48  of the openings  43  on the inner radius may decrease in size, as best shown in  FIG. 4 . In the illustrated embodiment, the openings  43  take the form of slots  47 , but those still in the art will appreciate that different sized and shaped openings would also fall within the scope of the present disclosure. In the illustrated embodiment, slots  47  may be oriented perpendicular to a central axis  14  of elongate hollow tube  40 , but other orientations would also fall within the intended scope of the present disclosure. Although not necessary, inner tube  50  may protrude through one or more of the plurality of openings  46  radially beyond an outer surface  49  of the elongate hollow tube  40  that surrounds the relevant openings  46  when the distal segment  41  is in the curved configuration  33  ( FIG. 4 ) and the inner tube  50  is pressurized as per the stiff condition  31 . 
       INDUSTRIAL APPLICABILITY 
       [0020]    The present disclosure finds general applicability in any wire guide. The present disclosure finds specific applicability for neuro-surgery applications. 
         [0021]    Referring again to  FIG. 1-5  and in addition to  FIGS. 6-11 , a method of operating the neuro-surgery assembly  10  is illustrated. The illustrations of  FIGS. 6-10  show a terminal segment of a tortuous pathway  2  to a treatment site  5  in a brain  3  of a patient  1 . Those skilled in the art will appreciate that a surgeon may, in the past, have had to repeatedly switch between relatively stiff and soft wire guides in order to incrementally move a neuro-catheter  20  to a treatment site  5  in the patient&#39;s brain  3 . However, by utilizing the wire guide  30  of the present disclosure, the physician may instead change the wire guide between a stiff condition  31  and a soft condition  32  in order to achieve the same purpose while utilizing only a single wire guide  30  in order to advance the neuro-catheter  20  to the treatment site  5 .  FIG. 6  shows wire guide  30  being advanced along tortuous pathway  2  while in a soft condition as evidenced by the low pressure indication on gauge  71 . After rounding the previous turn, the wire guide  30  may be placed in a stiff condition  31  and the neuro-catheter  20  advanced over wire guide  30  to achieve comparable positioning as shown in  FIG. 7 . Next, the wire guide  30  may be changed from the stiff condition  31  back to the soft condition  32  as evidenced by pressure gauge  71  in  FIG. 8 . The wire guide  30  may then be advanced around turn  4  of tortuous pathway  2  toward treatment site  5  in the patients brain  3  while the wire guide  30  is in the soft condition  32 . Next, at  FIG. 9 , the neuro-surgery assembly  10  may have an approach arrangement  11  in which the wire guide  30  is in the stiff condition  31  and the distal end  21  of neuro-catheter  20  is located proximal to the distal segment  41  of elongate hollow tube  40 . With wire guide  30  in the stiff condition  31 , wire guide  30  may be sufficiently stiff to allow neuro-catheter  20  to be maneuvered from the approach arrangement  11  to the arrival arrangement  12  as shown in  FIG. 10  in which the wire guide  30  is in a stiff condition  31  and the distal segment  41  of the wire guide  30  is positioned inside the neuro-catheter  20 . Thus, when transitioning from the approach arrangement  11  to the arrival arrangement  12 , the neuro-catheter  20  will be slid over wire guide  20  toward and around turn  4  and then over distal segment  41  to arrive at treatment site  5 . After stopping neuro-catheter  20  at treatment site  5 , the wire guide  30  may be changed back from the stiff condition  31  to the soft condition  32 .  FIG. 11  shows neuro-surgery assembly  10  being transitioned to a pre-treatment arrangement  13  in which the wire guide  30  is in the soft condition  32 , and the distal segment  41  is withdrawn into neuro-catheter  20  and separated from the distal end  21  by a withdrawal distance  28 . Those skilled in the art will appreciate that  FIG. 11  shows wire guide  30  being withdrawn from neuro-catheter  20  so that the treatment of treatment site  5  may commence using neuro-catheter  20  properly positioned as shown. For example, treatment site  5  may comprise a stenosis of a type known in the art, and neuro-catheter  20  may be utilized to deliver a stenosis dissolving treatment fluid to treatment site  5 , or some other treatment known in the art. 
         [0022]    Although the illustrations of  FIGS. 6-11  show how the neuro-surgery assembly  10  of the present disclosure successfully maneuvers a turn  4  in a tortuous path  2  to a treatment site  5 , those skilled in the art will appreciate that the wire guide  30  may be changed between the soft condition  32  and the stiff condition  31  a plurality of times while wire guide  30  is maneuvered from an entry site in the patient body  1  to the treatment site  5  within the brain  3 . Those skilled in the art will appreciate that wire guide  30  may be easily and atraumatically advanced around turns in the patient&#39;s anatomy while in the soft condition  32 , but may need to be changed to the stiff condition  31  in order to support advancement of neuro-catheter  20  around each successive turn on the way to a treatment site  5 . Although the present disclosure does not rule out the physician changing between different wire guides while attempting to approach treatment site  5  with a neuro-catheter  20 , many neuro-surgery procedures may allow for the use of a single wire guide  30  according to the present disclosure in order to gain access all the way to the treatment site. As such, one could expect the wire guide  30  to stop at treatment site  5 . Although not necessary, the inflation liquid  62  may include a radiopaque contrast in order to allow the physician to quickly assess the location and track the progress of wire guide  30  in a manner well known in the art. For purposes of the present disclosure, a neuro-catheter means a catheter of three French or less. 
         [0023]    It should be understood that the above description is intended for illustrative purposes only, and is not intended to limit the scope of the present disclosure in any way. Thus, those skilled in the art will appreciate that other aspects of the disclosure can be obtained from a study of the drawings, the disclosure and the appended claims.