Abstract:
An introducer and method provides a surgical tool with a pathway through tissue to a surgical site, wherein the surgical tool includes at least one surgical instrument. The introducer comprises a flexible sheath having a distal portion including a distal end and is arranged for receiving the surgical tool. A tissue separation tip at the distal portion of the sheath advances the sheath into the tissue towards the surgical site. The tissue separation tip is arranged to form a tissue gap and provide the at least one surgical instrument access to the tissue gap for performing a medical procedure consonant with the formation of the tissue gap or the performance of work at the surgical site.

Description:
PRIORITY CLAIM 
       [0001]    The present application claims the benefit of copending U.S. Provisional Patent Application Ser. No. 61/315,018, filed Mar. 18, 2010; the foregoing application is incorporated herein by reference in its entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The present invention is directed to a surgical device. The present invention is more particularly directed to an introducer for providing a surgical tool with a pathway to a surgical site. The present invention is still more particularly directed to such an instrument for use with surgical devices for robotic surgery, such as for example, robotic neurosurgery. 
         [0003]    Surgery has typically involved obtaining access to a region that exposes many aspects of a lesion (e.g. tumor, aneurysm, etc.) allowing its treatment or complete dissection and removal. However, obtaining access to the lesion may also involve damage to areas of the brain or other tissues that are normal. In view of the foregoing, a movement has developed to perform what is called “Minimally Invasive Surgery.” Unfortunately, this, in many instances, is a misnomer since the surgery may or may not be “minimally invasive” both to the critical tissues under consideration, but also to collateral tissues at the site of entry or along the access path. A better term for this type of surgery is “Minimal Access Surgery.” Examples of such surgery include: Endoscopic Surgery, Endoscope Assisted Surgery, Endovascular Surgery, Stereotactic Radiosurgery, etc. 
         [0004]    It is often necessary to treat brain tumors and aneurysms in the base of the skull. These are very difficult to treat because accessing the skull base requires disruption of many important structures. It is desirable to minimize the size of any opening to be made through the skull and surrounding, healthy tissues so that pathology in the skull base is treated with the least amount of potential damage to surrounding tissues. Such a procedure could be thought of as “Minimally Disruptive Surgery.” Current endoscopic and endoscope-assisted operations performed on the head, skull base, chest, abdomen, and other areas are done with rigid and straight endoscopes and tools that can only work in a straight line. However, in complex areas such as the brain, the endoscope has to negotiate many obstacles en route (e.g. bone, brain, and blood vessels). This imposes significant restrictions on the surgery being performed and can lead to an increase in collateral tissue damage, due to enlarging the access path and/or damaging or sacrificing the control over the structures near the lesion. Additionally, there are certain types of surgery that are at present not possible given the limitations posed by existing technology. 
         [0005]    On the other hand, today&#39;s endovascular surgery is often performed over comparatively great distance, and by navigating through a variety of curved channels. Such surgery uses a system of coaxial tubes and actuation cables that work on the basis of forward and backward movement, and side-to-side movement. Such devices are used with real-time imaging that guides the operator to the target. A similar approach is used with flexible endoscopes that work inside the gastrointestinal tract. However, these methods are not applicable for micro scale surgeries, as are performed for intricate neurosurgeries. 
         [0006]    In addition to the foregoing, it is sometimes desirable during surgical procedures to irrigate a surgical site, clean surgical tools, or repeatedly remove and re-introduce surgical tools. This presents a problem with currently known robotic surgical systems because removal of the entire system is generally required to change tools. 
         [0007]    In answer to the short comings and problems associated with the surgical tools mentioned above, a new and improved surgical device has been under development. This device is shown and described, for example, in co-pending application Ser. No. 12/943,745(our 2915-001-03) filed Nov. 10, 2010, for SURGICAL DEVICE, which application is incorporated herein in its entirety. The surgical device describe therein is a surgical device capable of steering surgical tools to surgical sites over curvilinear neurosurgery paths to avoid unnecessary damage to sensitive or critical collateral tissue. The device is capable of steering surgical tools around anatomical obstacles while affording the tools complete maneuverability at the surgical site and removal/replacement during neurosurgical procedures. 
         [0008]    While such a device represents a significant step forward for neurosurgical applications, the advancement would not be realized unless the surgical device could be delivered to the intended surgical site without causing damage to other tissue. What is thus required is an introducer that is capable of creating a working space for the surgical instrument by retracting adjacent tissue without causing undue trauma. For example, in neurosurgery, the introducer would need to be able to separate brain tissue from dura mater to create a channel to introduce the surgical tool. The tissue displacement must be both active and gentle. The introducer should desirably permit the surgical tools to be used during the surgical tool advancement procedure for visualization, connective tissue cutting and cauterizing in creating the instrument pathway and eventual surgical site. The present invention is directed to these and other issues. 
       SUMMARY 
       [0009]    The invention provides an introducer for providing a surgical tool with a pathway through tissue to a surgical site, wherein the surgical tool includes at least one surgical instrument. The introducer comprises a flexible sheath having a distal portion including a distal end and is arranged for receiving the surgical tool. The introducer further comprises a tissue separation tip at the distal portion of the sheath for advancing the sheath into the tissue towards the surgical site. The tissue separation tip is arranged to form a tissue gap and provide the at least one surgical instrument access to the tissue gap for performing a medical procedure consonant with the formation of the tissue gap or the performance of work at the surgical site. 
         [0010]    The tissue separation tip may comprise a plurality of fingers extending from and hingedly coupled to the sheath distal portion and be arranged to advance into the tissue when in a closed condition and to separate tissue to form the tissue gap when subsequently opened. The plurality of fingers may comprise at least two fingers. The introducer may further comprise a control cable for opening the fingers. The introducer may further comprise a control cable for closing the fingers. The introducer may further comprise an actuator associated with each finger, the actuators being operative individually or together for separate or concurrent opening of the fingers. The actuators may be operative in groups of two or more for opening different groups of the fingers by different amounts. The introducer may further comprise webbing bridging adjacent fingers to apply substantially uniform distributed pressure on the separated tissue. 
         [0011]    The tissue separation tip may include a plurality of inflatable members which, when inflated, serve to separate the tissue and form the tissue gap. The introducer may further include at least one conduit communicating with the inflatable members for providing the inflatable members with an inflating fluid. The plurality of inflatable members may be arranged for individual or concurrent inflation. The plurality of inflatable members may be arranged for inflation of selected groups of two or more inflatable members. 
         [0012]    The tissue separation tip may include a plurality of inflatable members which, when inflated, serve to separate the tissue and form the tissue gap. The inflatable members may be deflatable and the tissue separation tip may further include a plurality of fingers extending from and hingedly coupled to the sheath distal portion arranged to open as the inflatable members are deflated for maintaining the tissue gap formed by the inflatable members while also maintaining substantially constant pressure on the separated tissue. Each respective given one of the inflatable members may be carried by a respective given one of the fingers. The plurality of fingers may comprise at least two fingers and the plurality of inflatable members may comprise a like plurality of at least two inflatable members. The introducer may further comprise a control cable for opening the fingers. The introducer may further comprise a control cable for closing the fingers. 
         [0013]    The introducer may further comprise a plurality of control cables. The control cables may be arranged for closing the fingers in selectable groups of two or more for concurrent closing of selected groups of fingers by differing amounts. The introducer may further comprise an actuator associated with each finger. The actuators may be operative individually or together for separate or concurrent opening of the fingers. The actuators may be operative in groups of two or more for opening different groups of the fingers by different amounts. 
         [0014]    The introducer may further comprise webbing bridging adjacent fingers to apply uniform distributed pressure on the separated tissue. The introducer may further include at least one conduit communicating with the inflatable members for providing the inflatable members with an inflating fluid. The plurality of inflatable members may be arranged for individual or concurrent inflation or for inflation of selected groups of two or more inflatable members. 
         [0015]    According to further aspects of the invention, an introducer provides a surgical tool with a pathway through tissue to a surgical site. The surgical tool includes at least one surgical instrument. The introducer comprises a flexible sheath having a distal portion including a distal end and arranged for receiving the surgical tool. 
         [0016]    The introducer further includes a tissue separation tip at the distal portion of the sheath for advancing the sheath into the tissue towards the surgical site. The tissue separation tip is arranged to form a tissue gap and provide the at least one surgical instrument access to the tissue gap for performing a medical procedure consonant with the formation of the tissue gap. The tissue separation tip includes a plurality of inflatable and deflatable balloons which, when inflated, serve to separate the tissue and form the tissue gap and a plurality of fingers extending from and hingedly coupled to the sheath distal portion carrying the balloons and arranged to open as the balloons are deflated for maintaining the tissue gap formed by the inflatable members while also maintaining substantially constant pressure on the separated tissue. 
         [0017]    According to further aspects of the invention, the invention provides a method of introducing a surgical tool to a surgical site within tissue, wherein the surgical tool includes at least one surgical instrument. The method comprises providing an introducer comprising a flexible sheath having a distal portion including a distal end and arranged for receiving the surgical tool and a tissue separation tip at the distal portion of the sheath, the tissue separation tip when in a first configuration being adapted for advancing the tip through the tissue and when in a second configuration adapted for separating the tissue. The method further includes inserting the surgical tool into the introducer sheath, advancing the tissue separation tip into the tissue with the separation tip being in the first configuration, placing the separation tip in the second configuration to separate the tissue with the separation tip to form a tissue gap, performing a medical procedure with the at least one surgical instrument consonant with the formation of the tissue gap, returning the separation tip to the first configuration, and further advancing the tissue separation tip into the tissue with the separation tip being in the first configuration. 
         [0018]    The tissue separation tip may include a plurality of inflatable members which, when inflated, serve to separate the tissue and form the tissue gap and the placing step may include inflating the inflatable members. The tissue separation tip may comprise a plurality of fingers extending from and hingedly coupled to the sheath distal portion and the placing step may include opening the fingers at the distal portion of the sheath. 
         [0019]    The tissue separation tip may comprise a plurality of fingers extending from and hingedly coupled to the sheath distal portion and a plurality of inflatable members which, when inflated, serve to separate the tissue and form the tissue gap. The placing step may include first inflating the inflatable members and thereafter opening the fingers at the distal portion of the sheath while deflating the inflatable members. 
         [0020]    The tissue separation tip may comprise a plurality of fingers extending from and hingedly coupled to the sheath distal portion and a plurality of inflatable members which, when inflated, serve to separate the tissue and form the tissue gap. The placing step may include first inflating the inflatable members and thereafter opening the fingers at the distal end of the sheath while deflating the inflatable members and maintaining substantially constant pressure on the separated tissue. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. The invention, together with further features and advantages thereof, may best be understood by making reference to the following description taken in conjunction with the accompanying drawings, in the several figures of which like reference numerals identify identical elements, and wherein: 
           [0022]      FIG. 1  is side view, with portions cut away, of an introducer device embodying the present invention in a first configuration of use; 
           [0023]      FIG. 2  is an end view of the introducer of  FIG. 1 ; 
           [0024]      FIG. 3  is an end view showing an alternative embodiment of the introducer device of  FIG. 1 ; 
           [0025]      FIG. 4  is a side view, with portions cut away, of the introducer device of  FIG. 1  shown in a second configuration of use; 
           [0026]      FIG. 5  is a side view, with portions cut away, of the introducer device of  FIG. 1  shown in a third configuration of use; 
           [0027]      FIG. 6  is a side view, with portions cut away, of the introducer device of  FIG. 1  during the preparation for the performance of a medical procedure while the introducer device is in the third configuration of use; 
           [0028]      FIG. 7  is a side view, with portions cut away, showing the performance of a medical procedure while the introducer device of  FIG. 1  is in the third configuration of use; 
           [0029]      FIG. 8  is side view, with portions cut away, of another introducer device embodying the present invention in a first configuration of use; 
           [0030]      FIG. 9  is a side view, with portions cut away, of the introducer device of  FIG. 8  shown in a second configuration of use; 
           [0031]      FIG. 10  is a side view, with portions cut away, of the introducer device of  FIG. 8  shown in a third configuration of use; 
           [0032]      FIG. 11  is a simplified perspective view illustrating the manner in which the introducer devices may be configured for selective actuation in accordance with further aspects of the present invention; 
           [0033]      FIG. 12  is a side view of a still another introducer device embodying the present invention; and 
           [0034]      FIG. 13  is a perspective view showing details of the actuator  70  of the introducer device of  FIG. 10 . 
       
    
    
     DETAILED DESCRIPTION 
       [0035]      FIG. 1  is a side view of an introducer device  10  embodying the present invention. The introducer  10  generally includes a sheath  12  and a tissue separation tip  14 . The introducer has a proximal portion  16  and a distal portion  18  that includes the separation tip  14 . 
         [0036]    The sheath  12  is dimensioned for receiving a surgical tool  20  therein. The surgical tool may be, for example, the surgical device shown and described in the aforementioned co-pending application Ser. No. 12/943,745, filed Nov. 10, 2010, for SURGICAL DEVICE, which application is incorporated herein in its entirety. To that end, the surgical tool  20  includes a sheath  22 . At the distal end of the sheath  20  are tool supports  24  and  26 . The sheath  20  and supports  24  and  26  accommodate tool conduits  28  and  30 . The conduits permits surgical instruments to be inserted into the tool  20  or removed there from during a medical procedure without requiring the entire tool  20  from being removed from the patient. As will be seen subsequently, as the introducer separates tissue to form tissue gaps, the surgical instruments may be advanced through the tool  20  and used to perform a medical procedure consonant with the formation of the tissue gap. Such procedures may include visualization, connective tissue cutting and cauterizing. Still further, once the surgical site is reached, the introducer may serve to maintain the surgical site and permit performance of work at the surgical site. 
         [0037]    The introducer  10  includes a plurality of fingers extending from the sheath  12  in the distal direction. The number of fingers employed in the introducer may vary depending upon the circumstances. In accordance with this embodiment, and may be seen in  FIG. 2 , the introducer  10  includes four fingers,  40 ,  42 ,  44 , and  46 . The fingers are hingedly connected to the distal portion  18  of the  12 . Also, as may be seen in  FIG. 3 , the introducer  100  there shown includes six fingers, fingers  102 ,  104 ,  106 ,  108 ,  110 , and  112 . 
         [0038]    The introducer  10  further comprises a like plurality of inflatable members or balloons  50 ,  52 ,  54 , and  56 . Each balloon is associated with and carried by one of the respective fingers  40 ,  42 ,  44 , and  46 . Each of the inflatable members or balloons has a conduit that provides it with inflating fluid. To that end, balloon  50  is associated with conduit  50   a , balloon  52  is associated with conduit  52   a , balloon  54  is associated with conduit  54   a , and balloon  56  is associated with conduit  56   a . All of the balloons may be inflated concurrently or in selectable groups. 
         [0039]    The combination of the balloons and the fingers provides a positive but gentle separation of tissue during surgical tool advancement towards the surgical site. As the balloons or selected balloons or balloon groups are inflated, the tissue is first separated to form a tissue gap. Thereafter, selected fingers, selected groups of fingers, or all of the fingers are opened as the balloons are deflated. This maintains the tissue gap formed by the inflatable members while also maintaining substantially constant pressure on the separated tissue. The forgoing is illustrated in the follow sequence of  FIGS. 4-7 . 
         [0040]    In use, the introducer  10  in a first configuration as shown in  FIG. 1  is deployed at an entry point. Then, the balloons  50 ,  52 ,  54 , and  56  are inflated to gently displace and separate the tissue to form a tissue gap as shown in  FIG. 4 . The introducer is now in a second configuration. Next, as seen in  FIG. 5 , the fingers  40 ,  42 ,  44 , and  46  are opened. As the fingers are opened, the balloons  50 ,  52 ,  54 , and  56  are deflated. As the fingers are opened and the balloons are deflated, the tissue gap is maintained while substantially constant pressure is maintained on the separated tissue. The introducer is now in a third configuration of use. 
         [0041]    With the introducer  10  in the third configuration of use, as seen in  FIG. 5 , it may be made ready for the performance of medical procedures. As seen in  FIG. 5 , the introducer, while in the third configuration of use, presents the separated tissue to one or more medical instruments to be employed in procedures such as visualization, connective tissue cutting and cauterizing consonant with advancement of the introducer  10 .  FIGS. 6 and 7  illustrate the medical procedures being performed. 
         [0042]    Once the tissue gap has been formed and the medical procedures are completed, the process returns to placing the introducer back into the first configuration as shown in  FIG. 1 . The separation tip  14  may then be advanced and the foregoing procedure repeated until the surgical site is reached. Once the surgical site is reached, the introducer may be used to maintain the surgical site for the physician during the primary medical procedure. 
         [0043]    Referring now to  FIGS. 8-10 , they show the distal portions of another introducer device embodying the invention. The introducer  60  includes a sheath  62  and a tissue separation tip  64 . The tissue separation tip  64  includes a plurality of fingers, two of which are shown at  66  and  68 . As in the previous embodiment, the device may have two or more fingers. In some embodiments, the device may have four fingers, in other embodiments six, and in other embodiments even a greater number of fingers.  FIG. 8  shows the introducer in the first, closed, configuration. Each finger is associated with an actuator for opening the finger. In  FIG. 8 , for example, finger  66  is associated with actuator  70  and finger  68  is associated with actuator  72 . The actuators are hingedly carried on the sheath in the distal portion of the sheath  62 . As may be noted in  FIG. 8 . finger  66  is connected to the sheath distal portion by a hinge  74  and finger  68  is connected to the sheath distal portion by a hinge  76 . The manner in which the actuators open the fingers will be described in detail subsequently. The introducer  60 , when in the first configuration as shown in  FIG. 8  is ready to be placed at an entry site or to be advance further into tissue. 
         [0044]    As in the previous embodiment, the introducer  60  further includes a plurality of inflatable members. In accordance with this embodiment, each finger is associated with and carries an inflatable member. To that end, finger  66  carries inflatable member  78  and finger  68  carries inflatable member  80 .  FIG. 9  shows the introducer  60  in the second configuration with the inflatable members  78  and  80  inflated. As in the previous embodiment, as the inflatable members are inflated, adjacent tissue is gently separated or displaced. Each inflatable member  78  and  80  is associated with a conduit  82  and  84  respectively. The conduits permit the inflatable members to be filled with an inflating fluid, such as saline. The conduits may be arranged to inflate each inflatable member individually, or arranged to inflate the conduits in selective groups. The inflatable members or groups of inflatable members may be inflated concurrently or in any desired order or as required. 
         [0045]      FIG. 10  shows the introducer  60  in its open or third configuration. To open each finger, each finger is associated with an actuator. Finger  66  is associated with actuator  70  and finger  68  is associated with actuator  72 . As previously mentioned, the fingers are each hingedly connected to the sheath  62 . Actuator  70  causes finger  66  to open about hinge  74  and actuator  72  causes finger  68  to open about hinge  76 . Each actuator includes a spring member that acts upon its respective finger to open the finger. Actuator  70  includes spring member  86  and actuator  72  includes spring member  88 . The springs are biased to maintain contact with its finger. However, when the ends of the spring members are pulled back, the springs bow. This forces the fingers to open. More specifically, spring member  86  is connected to a control cable  90  and spring member  88  is connected to a control cable  92 . Control cable  90  is shown in greater detail in  FIG. 13 . Here, it may be seen that the cable  90  loops around the spring member  86  and is once again connected to itself. When the cables  90  and  92  are pulled in direction of arrow  94 , the spring members  86  and  88  bow out and push on their respective finger  66  and  68 . As a result, fingers  66  and  68  are opened. 
         [0046]    The spring members may be acted upon by the control cables concurrently for concurrently opening the fingers. Also, the spring members may be acted upon by the control cables individually in any desired or required order to open individual fingers completely or by varying amounts. Alternatively, the spring members may be acted upon to open the fingers in groups. This is shown, for example in FIG.  11 . In this simplified drawing, the spring members are arranged in groups, group  120  and group  122 . Group  120  includes spring members  124  and  126 . Group  122  includes spring members  128  and  130 . The springs of the spring member groups are connected together by a common connector. Common connector  132  is connected to spring members  124  and  126  and common connector  134  is connected to spring members  128  and  130 . Each connector is connected to a control cable. Connector  132  is connected to control cable  136  and connector  134  is connected to control cable  138 . When the control cables are pulled in the direction of arrows  140 , the spring members of each group are bowed together, causing the respective fingers to open together. Hence, the pulling of control cable  136  bows spring members  124  and  126  together and the pulling of control cable  138  causes spring members  128  and  130  to bow together. The groups of fingers may be opened concurrently or in a sequence as desired or required. 
         [0047]    Returning now to  FIG. 10 , each of the fingers  66  and  68  is associated with a retraction cable  96  and  98 . The retraction cable may be employed, if necessary, to close the fingers  66  and  68  respectively. In actual practice, the fingers may be closed by the force of tissue. However, when needed, the retraction cables  96  and  98  may be relied upon to close their respective fingers. 
         [0048]    As in the previous embodiment, it is contemplated that as each finger  66  and  68  is opened, the corresponding inflatable member or balloon  78  and  80  is deflated. The deflation of the balloons as the fingers open serves to maintain the tissue separation or tissue gap while also maintaining a substantially constant pressure on the separated tissue. 
         [0049]    The introducer  60  as shown in  FIG. 10  presents the tissue gap or surgical site to the one or more instruments that may be received by the sheath  62 . The device as described in the aforementioned co-pending application is preferably received by the sheath  62  and used to steer the introducer. Hence while the surgical device within the sheath performs the steering function, the introducer enabled the advancement of the assembly. 
         [0050]    Referring now to  FIG. 12 , it shows another introducer device embodying the invention. The device  150  includes a sheath  152  and a tissue separation tip  154 . As in the previous embodiments, the tissue separation tip includes a plurality of fingers  156  and a like plurality of inflatable members  158  carried by the fingers  158 . Between the fingers  158  is a web  160 . The web provides substantially uniform support for the separated tissue when the introducer is in the third configuration of  FIG. 10 . As may be appreciated by those skilled in the art, the web may also be employed in the embodiments of  FIGS. 8-11  for providing substantially uniform support for the separated tissue. Further, the embodiments of  FIGS. 1-7  may also include control cables for opening and closing the fingers. The control cables may extend proximally along the introducer sheath in a manner similar to the control cables of the surgical device of co-pending application Ser. No. 12/943,745, for connection to a control assembly. 
         [0051]    In each embodiment disclosed herein, the sheath may be compositely formed of one or more flexible materials such as, for example, PVDF (polyvinylidene flouride), Nylon (Polyamide), Polyethylene terephthalate (PET), or polycarbonate. Similarly, the fingers and actuators may be compositely formed of one or more flexible material such as, for example, Nitinol (Nickel Titanium), spring steel, stainless steel, titanium, PVDF (polyvinylidene flouride), Nylon (Polyamide), Polyethylene terephthalate (PET), or polycarbonate. Such materials are well known in the art. 
         [0052]    While a particular embodiment of the invention has been shown and described, changes and modifications may be made. It is therefore intended to cover in the appended claims all such changes and modifications which fall within the true spirit and scope of the invention.