Abstract:
A laparoscopic nephrectomy device is disclosed. The device has an upper jaw and a lower jaw designed to clamp a portion of an organ, such as a kidney, so as to cut off blood flow locally to a portion of that organ. The upper jaw includes a mid-jaw piece and a top jaw piece, with each piece separately articulated. The mid-jaw piece is pivotably connected to the lower jaw. A top jaw piece is pivotably connected to the mid-jaw piece. The mid-jaw and top jaw pieces include a mechanism to fix the angular orientation of the mid-jaw and top jaw pieces with respect to one another, including a retractable slide piece that is carried by the mid-jaw piece and received in a slot in the top jaw piece. The jaws have insulated troughs that carry electrode structure for applying coagulative therapies.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Provisional Patent Application No. 61/166,345, filed Apr. 3, 2009. The entire contents of that application are incorporated by reference herein in their entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The invention relates generally to the field of medical and surgical instruments, and more particularly to surgical instruments for manipulating and clamping the kidneys. 
         [0004]    2. Description of Related Art 
         [0005]    A nephrectomy is a surgical procedure in which a kidney is removed. Nephrectomies may be performed, for example, in cases of renal cell carcinoma, kidney deformity, trauma, and for live donor transplants. In a typical nephrectomy, the connections of the kidney to the renal artery and vein and to the ureter are severed and the kidney is removed. In 2008, 55,000 nephrectomies were performed, of which 50% were performed laparoscopically, i.e., through several small incisions in the abdomen, rather than by directly exposing the kidney with a large incision. 
         [0006]    However, a full or “radical” nephrectomy is not indicated in every case. A partial nephrectomy, removal of only a portion of a kidney, may be indicated, for example, in cases in which there is a tumor in one kidney and the other kidney is functioning poorly, or in cases in which there are tumors in both kidneys. In general, partial nephrectomies may result in less morbidity, less blood loss, shorter recovery time, reduced need for pain medication, and conserved kidney function. 
         [0007]    In a partial nephrectomy, although only a portion of the kidney is removed, the renal artery is typically clamped, cutting off blood flow to the entire kidney, not just the portion requiring removal. Once the renal artery has been clamped, the surgeon has 30 minutes to excise the tumor, restore hemostasis, and repair both the urine collection system and the defect created by the procedure. After 30 minutes, ischemia from lack of blood flow can cause tissue damage. Thus, the procedure is difficult and has a steep learning curve. Tools and procedures that allow for clamping off only an affected portion of the renal blood supply would make the partial nephrectomy easier and perhaps make the procedure more widely used. 
         [0008]    Unfortunately, surgical tools that allow for clamping off only a portion of the renal blood supply are relatively few. As one example, U.S. Patent Application Publication No. 2004/0158286 discloses a hemostatic tissue clamp. However, most embodiments of that clamp are designed to be used only with an open surgical procedure, in which the entire kidney is exposed. Those embodiments that are designed for laparoscopic use have an extremely complex jaw mechanism. 
       SUMMARY OF THE INVENTION 
       [0009]    One aspect of the invention relates to a laparoscopic nephrectomy device. The device is shaped and proportioned to be inserted through a laparoscopic port and is adapted to clamp a portion of an organ, such as a kidney, such that blood flow is interrupted locally. The end effector of the device includes a lower jaw piece and an upper jaw with two separate articulations. Specifically, a mid-jaw piece is pivotably connected with the lower jaw piece and is also coupled to a handle mechanism such that the handle mechanism can drive the upper jaw between open and closed positions. A top jaw piece is pivotably connected to the distal or forward end of the mid-jaw piece. The mid-jaw and top jaw pieces also include a mechanism for maintaining the top jaw piece in a specific angular orientation with respect to the mid-jaw piece. Specifically, the mid-jaw piece carries a slide piece that is biased forwardly by a resilient elastic member, such as a spring. The top jaw piece has a corresponding angled slot, which is sized and positioned to receive the slide piece from the mid-jaw piece. As the jaws are driven open, the slide piece pushes into the slot in the top jaw piece, locking the top jaw piece in its angular orientation with respect to the mid-jaw piece. This double articulation allows the top jaw piece to be substantially parallel with the bottom jaw piece at a specified distance, which, in turn, allows for more even pressure distribution on the renal capsule when a kidney is clamped. 
         [0010]    The device may include electrically and thermally insulated troughs that carry electrode structure, such that the device is adapted to apply coagulative therapies, such as radiofrequency (RF) coagulative therapy, to the clamped organ or tissue. 
         [0011]    Another aspect of the invention relates to end effectors for laparoscopic surgical instruments. The end effectors have the properties described above. 
         [0012]    Other aspects, features, and advantages of the invention will be set forth in the description that follows. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING FIGURES 
         [0013]    The invention will be described with respect to the following drawing figures, in which like numerals represent like features throughout the figures, and in which: 
           [0014]      FIG. 1  is a perspective view of a laparoscopic nephrectomy device according to one embodiment of the invention; 
           [0015]      FIG. 2  is a cross-sectional view of a portion of the laparoscopic nephrectomy device of  FIG. 1 , shown as being inserted through a laparoscopic port; 
           [0016]      FIG. 3  is a cross-sectional view of a portion of the laparoscopic nephrectomy device of  FIG. 1  with its jaw open; 
           [0017]      FIG. 4  is an enlarged cross-sectional view of a portion of the laparoscopic nephrectomy shown in  FIG. 3 ; 
           [0018]      FIG. 5  is a perspective view illustrating the laparoscopic nephrectomy device of  FIG. 1  in use, clamping the blood supply of a diseased portion of a kidney; and 
           [0019]      FIG. 6  is a perspective view similar to the view of  FIG. 5 , illustrating the kidney after using the laparoscopic nephrectomy device to apply coagulative therapy. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]      FIG. 1  is a perspective view of a laparoscopic nephrectomy device, generally indicated at  10 , according to one embodiment of the invention. The use of the device  10  in nephrectomies and partial nephrectomies will be described below; however, the device  10  need not be limited to, or used only for, those procedures. 
         [0021]    The device  10  is an elongate instrument with an end effector  12  that is particularly adapted to clamp a portion of an organ, such as a kidney, and to apply coagulative therapies, such as radio frequency (RF) coagulation, to that organ. At the other end of the device  10 , manipulating structure  14  is used by the physician or surgeon to position and actuate the end effector. Generally speaking, the device  10  is particularly adapted for use in laparoscopic surgical procedures, and to that end, the device  10  is long enough to allow the end effector  12  to be inserted into a body cavity through a laparoscopic port while the manipulating structure  14  remains outside of the body cavity, as will be described below. As shown in  FIG. 1 , the length of the device  10  between the manipulating structure  14  and the tip of the end effector  12  is generally cylindrical in overall shape, so as to facilitate insertion through a laparoscopic port. However, as those of skill will understand, embodiments of the invention need not be limited to laparoscopic procedures; the sizes, proportions, contours, and manipulating structure  14  of the device  10  may be modified in order to adapt the device  10  for use in open surgical procedures, if desired. 
         [0022]    In the device  10 , the manipulating structure  14  comprises a set of grips  16 ,  18  and associated structure. A first or stationary grip  16  is fixedly attached to a rod  20  that connects to and forms a part of the end effector  12 . A second, movable grip  18  is pivotably connected to the stationary grip  16  at a grip pivot  22 , so that it moves relative to the stationary grip  16 . Thus, the two grips  16 ,  18  can be squeezed together or driven apart in a scissor-like movement. 
         [0023]    The end effector  12  of the device  10  has two separate points of articulation in its upper jaw. A bottom jaw piece  24  arises from and comprises the distal end of the rod  20 . A mid-jaw piece  26  is pivotably attached to the bottom jaw piece  24  at a first jaw pivot  29 . A top jaw piece  28  is attached to the distal end of the mid-jaw piece  26  at a second jaw pivot  30 . In the position shown in  FIG. 1 , the mid-jaw piece  26  extends at an acute angle up from the first jaw pivot  29 . The jaw pieces  24 ,  26 ,  28  are generally half-cylindrical in shape, such that when the end effector  12  is closed, it also has a generally cylindrical shape. As one example of suitable proportions for the jaw pieces  24 ,  26 ,  28 , the bottom jaw piece  24  may have a length of about 123 mm from its point of attachment to the mid-jaw piece  26 , the mid-jaw piece  26  may have a length of about 67 mm, and the top jaw piece  28  may have a length of about 68 mm. The width of the end effector  12  and its components may be about 10 mm. 
         [0024]      FIG. 2  is a cross-sectional view of the device  10  being inserted through a laparoscopic port  32 . The movable grip  18  is coupled to a push rod  34  that extends through the rod  20  and connects to the mid-jaw piece  26  at a push rod pivot  36 . The push rod pivot  36  is just below and rearward of the first jaw pivot  29 , such that when the movable grip  18  is pushed toward the fixed grip  16 , the push rod  34  is pulled rearwardly and drives the mid-jaw piece  26  to rotate clockwise about the first jaw pivot  29 , toward the bottom jaw piece  24 . In the position shown in  FIG. 2 , the movable grip  18  is closed against the stationary grip  16 , which maintains the end effector  12  in the position shown. Conversely, when the two grips  16 ,  18  are pulled apart, the push rod  34  is pushed forwardly, causing the mid jaw piece  26  to rotate counterclockwise about the first jaw pivot  29 . The locations of the first jaw pivot  29  and the push rod pivot  36  are chosen so as to maximize mechanical advantage given the size constraints, which lowers the amount of force needed to open and close the end effector  12 . 
         [0025]      FIGS. 3 and 4  illustrate the opening of the end effector  12  and the mechanism by which the position of the mid-jaw piece  26  and the top jaw piece  28  maintain position with respect to one another. The mid-jaw piece  26  carries a slide piece  38  within a channel  40  in the mid-jaw piece  26 . A resilient elastic member  42 , in this case, a compression spring, bears between the slide piece  38  and the back of the channel  40  in which the slide piece  38  rests. The resilient elastic member  42  biases the slide piece  38  forwardly. 
         [0026]    The resilient elastic member  42  is best seen in the enlarged view of  FIG. 4 . More specifically, as shown in that figure, the rear portion  39  of the slide piece  38  is narrowed, and the elastic member  42  encircles it and bears against the shoulder  41  created by the narrowing of the slide piece  38 . 
         [0027]    In the fully closed position of  FIG. 2 , the beveled front edge  44  of the slide piece  38  rests against the proximal edge  47  of the top jaw piece  28 . As the grips  16 ,  18  are actuated to open the end effector  12 , the slide piece  38  is driven by the resilient elastic member  42  into a slot  45  in the top jaw piece  28 . The beveled front edge  44  of the slide piece  38  and the rounded contour of the proximal edge  47  of the top jaw piece  28  may assist the slide piece  38  in aligning itself with the slot  45 . In the illustrated embodiment, the slot  45  is angled upwardly, with an angle of 10 degrees from the horizontal. Other embodiments may use other angles, depending on the desired angular relationship between the mid-jaw piece  26  and the top jaw piece  28 . When the end effector  12  is in the open position shown in  FIG. 1 , the slide piece  38  is in the position shown in the enlarged cross-sectional view of  FIG. 4 . 
         [0028]    The angle of the mid-jaw piece  26  and the relationship of the mid-jaw piece  26  with the top jaw piece  28  allow the top jaw piece  28  and bottom jaw piece  24  to be substantially parallel to one another when the two jaw pieces  24 ,  28  are a specified distance apart. For example, the two jaw pieces  24 ,  28  may be substantially parallel to one another when they are approximately 2.5 cm apart. This allows the end effector  12  to exert more even pressure on the renal capsule when the kidney is clamped. Of course, the specified distance may vary from embodiment to embodiment and application to application. In this context, 2.5 cm is assumed to be about the jaw distance necessary to effectively clamp a portion of a kidney. 
         [0029]    The device  10  also includes a mechanism to disengage the slide piece  38  from the slot  44 , so that the end effector  12  can be returned to the position shown in  FIG. 2 . Specifically, a wire or pull cord  46  is connected to the proximal (rear) portion of the slide piece  38 . The pull cord  46  is generally inelastic and inextensible, although it may have at least some degree of flexibility. The pull cord  46  transits the rod  20  through a channel  48  in the rod  20 . At the rear of the device  10  near the manipulating structure, a transversely-extending gripping structure or cord pull  50  is connected to the cord  46  and rides in a horizontal slot  51 . When the cord pull  50  is pulled back, the slide  38  is pulled out of the slot  44  by the wire  46 . As the end effector  12  is closed, the slide  38  returns to the position shown in  FIG. 2 . 
         [0030]    As was described briefly above, the device  10  is constructed and adapted to apply coagulative therapies to the tissue that is clamped by the end effector  12 . In the illustrated embodiment, each of the top and bottom jaw pieces  24 ,  28  has a trough  52 ,  54 . These troughs  52 ,  54  are filled with an electrically and thermally insulating material  56 , such as a plastic resin. For example, a polyetherimide resin like ULTEM® 1000 polyetherimide resin may be used. Provided in or on the insulating material  56  is electrode structure  58  suitable for applying bipolar electrocautery or other forms of coagulative therapy. In the illustrated embodiment, the electrode structure  58  comprises respective pluralities of electrically conductive posts or needles. In other embodiments, the electrode structure  58  may comprise metallic strips or other similar structure, and the electrode structure in the top jaw piece  28  and bottom jaw piece  24  may differ from one another. 
         [0031]    The bottom, mid-jaw, and top jaw pieces  24 ,  26 ,  28  include conduits or channels  60 ,  62 ,  64  that allow wires and/or other forms of electrical connecting structure to pass through the end effector  12  to connect with the electrode structure  58 . (As can be appreciated from the figures, corresponding channels are provided in the rod  20 , generally contiguous with the channels in the end effector  12  itself.) The wires (not shown in the figures) may be insulated or passivated as necessary. As shown in  FIG. 1 , the proximal end of the device  10  near the manipulating structure  14  may include a connector to connect to an RF generator  66 . The RF generator  66  may, for example, apply 490 kHz energy. As those of skill in the art will realize, the connection shown between the device  10  and the RF generator  66  in  FIG. 1  is schematic. The manner of connection may vary from embodiment to embodiment, based both on the specific characteristics of the device  10  and the characteristics of the RF generator  66 . 
         [0032]      FIGS. 5 and 6  are perspective views of a portion of the device  10  with a kidney  100 , illustrating the device  10  in use. In  FIG. 5 , the end effector  12  of the device  10  is clamping a kidney  100  proximate to a tumor  102 . As was described above, when the end effector  12  is in the position shown in  FIG. 5 , the top jaw piece  28  and the bottom jaw piece  24  are substantially parallel. In some embodiments, the jaw pieces  24 ,  28  may have an additional layer of soft, conforming material on the faces that contact the kidney  100 , so as to further reduce the force exerted on the renal capsule or to better distribute that force. 
         [0033]    Once the end effector  12  is engaged, coagulative therapies can be applied, as shown in  FIG. 6 , leaving a cauterized area of tissue  104  around the end effector  12 . For example, in preliminary tests with ex vivo porcine kidneys, settings of 20 watts for two minutes using a 490 kHz RF generator were found to provide adequate coagulation. In similar in vivo testing, also with porcine kidneys, 20 watts for four minutes were found to provide adequate coagulation. 
         [0034]    As was described briefly above, the surgeon would generally apply manual force to the grips  16 ,  18  in order to engage the end effector  12 . The locations of the pivots  29 ,  34  are selected so as to maximize the mechanical advantage of the device  10  and minimize the force. However, especially when coagulative therapies are being applied, it may be necessary to maintain the end effector  12  in the clamped state for an extended period of time, on the order of several minutes. In order to promote uniform application of force over time and to prevent hand cramping that might occur with long-term clamping, the manipulating structure  14  of the device  10  may include a locking mechanism for the grips  16 ,  18  that maintains the two grips  16 ,  18  in a desired position without the application of continued manual pressure. A number of these types of locking mechanisms are known in the art, and any one of these may be used. 
         [0035]    Although  FIGS. 5 and 6  show the use of the device to clamp and apply electrocoagulative therapy along a single line proximate to the renal pole, the device  10  may be used in many ways. In some procedures, it may be advantageous or necessary to clamp and coagulate in multiple places forming, e.g., a wedge shape. As those of skill in the art will realize, the device  10  may be applied multiple times in multiple places, if desired. The device  10  may also be used to provide additional or repeated coagulative therapy to the same location. 
         [0036]    The device  10  may be made of any suitable biocompatible material, including metals, such as surgical stainless steels. Other materials, such as plastics, may be used in some embodiments, although it may be helpful if the materials that are used are autoclavable or otherwise able to be sterilized. 
         [0037]    Although the above description focuses on the complete device  10 , those of skill in the art will realize that the end effector  12  may be attached to any sort of manipulating structure, and that manipulating structure may or may not resemble the manipulating structure  14  of the illustrated embodiment. The manner in which the end effector  12  is actuated is not critical to the invention so long as it is easily and reliably used by the physician or surgeon. To that end, one advantage of the manipulating structure  14  is that it actuates the end effector  12  using familiar movements of the hands. 
         [0038]    While the invention has been described with respect to certain embodiments, the description is intended to be exemplary, rather than limiting. Modifications and changes may be made within the scope of the invention, which is defined by the appended claims.