Abstract:
A surgical device for manipulating tissue. The device includes an elongated shaft having a proximal end and a distal end extending therefrom. There is also an elongated end effector having a proximal end attached to the distal end of the shaft, a distal end extending therefrom. The end effector has first and second opposing jaws which are movable with respect to each other from an open position, wherein the jaws are spaced apart, to a closed position wherein the jaws are in close approximation to one another. At least one of the jaws has an expandable member disposed thereon for selectively increasing the size of the jaw in a direction perpendicular to the longitudinal axis so as to increase the rigidity of the end effector.

Description:
This application is related to the copending U.S. patent application Ser. No. 10/247,897, which is hereby incorporated herein by reference. 
   FIELD OF THE INVENTION 
   The present invention has application in conventional endoscopic and open surgical instrumentation as well as application in robotic or power assisted surgery. The present invention relates, in general, to an expandable member to stiffen a jaw of a surgical device and, more particularly, to an anvil cap movable to a position to increase the height of an anvil of an endoscopic linear cutter. 
   BACKGROUND OF THE INVENTION 
   Medical devices to simultaneously cut and staple tissue in a surgical patient, often called linear cutters, are commonly used in endoscopic surgery. In endoscopic surgery, linear cutters are placed into the patient through a cannula having a small orifice. Each linear cutter generally has an end-effector in the form of a cartridge, for holding and ejecting staples, and an anvil, for forming the ejected staple into the proper shape. After passing through the cannula, the cartridge and anvil are clamped around tissue to be cut and stapled to compress the tissue and stem blood flow. The tissue exerts a reactive force against the cartridge and the anvil of the device. Examples of linear cutters can be found in U.S. Pat. Nos. 6,032,849 and 5,673,840, both of which are hereby incorporated herein by reference. 
   An anvil of a linear cutter has depressions positioned within it. Each depression receives the legs of a “C” shaped staple ejected towards it and bends the legs of the staples to form “B” shaped closures. To keep each pocket positioned in the correct position and at the correct distance from the cartridge, it is advantageous to minimize anvil deflection. Force exerted against the anvil from the tissue causes bending of the anvil and channel of the end-effector in a plane orthogonal to the tissue surface. The bending displaces the staple-forming portion of the anvil from the optimum position to receive an ejected staple, and may result in malformation of staples. The malformation has a greater potential for occurring when the cartridge and the anvil of the device are made longer. 
   A technique for creating a stiffer anvil is to increase the dimension of the anvil in the plane of bending. This dimension is commonly called the height of the anvil, and increasing the height of the anvil can also enlarge the cross-sectional area of the anvil. However, the benefits of endoscopic surgery stem from creating small incisions on the patient. Small incisions use small cannulas, and a small cross-sectional area for the anvil is desirable to fit the jaws of the device through a small cannula. Longer working jaws are desirable, but jaw length has been limited by the need to maintain small cross-sectional area and efficacious staple formation. Deflection needs consideration not only in the design of endoscopic linear cutters, but also in any endoscopic device having an attached implement that receives a reactive force from tissue or the work being performed. 
   Because of the benefits of a small incision, there has been a desire to use an implement that will have a short height to facilitate entry through a small orifice and that will expand to a greater height to become more rigid while being used inside the body. The present invention provides for a surgical device having a working implement with a movable device that can be raised to increase the implement rigidity, and that can be lowered to decrease implement height to facilitate insertion through a cannula. 
   SUMMARY OF THE INVENTION 
   In accordance with the present invention, there is provided a surgical device for manipulating tissue. The device includes an elongated shaft having a proximal end and a distal end extending therefrom. There is also an elongated end effector having a proximal end attached to the distal end of the shaft, a distal end extending therefrom. The end effector has first and second opposing jaws which are movable with respect to each other from an open position, wherein the jaws are spaced apart, to a closed position wherein the jaws are in close approximation to one another. At least one of the jaws has an expandable member disposed thereon for selectively increasing the size of the jaw in a direction perpendicular to the longitudinal axis so as to increase the rigidity of the end effector. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The novel features of the invention are set forth with particularity in the appended claims. The invention itself, however, both as to organization and methods of operation, together with further objects and advantages thereof, may best be understood by reference to the following description, taken in conjunction with the accompanying drawings in which: 
       FIG. 1  is an isometric view of an endoscopic linear cutter having an expandable member according to an embodiment of the invention. 
       FIG. 2  is an isometric exploded view of the shaft of the linear cutter of  FIG. 1 . 
       FIG. 3  is a fragmentary side elevation view of a slot within the tube shown in  FIG. 2 . 
       FIG. 4  is an isometric view of the anvil depicted in  FIG. 2 . 
       FIG. 5  is a side elevation view, partially in section, of the shaft of the linear cutter of  FIG. 1  showing the anvil closed against the cartridge and the anvil cap lowered into a cavity of the anvil. 
       FIG. 6  is a section view taken along line  6 — 6  of  FIG. 5  depicting the anvil cap lowered into a cavity of the anvil. 
       FIG. 7  is a side elevation view, partially in section, of the shaft of the linear cutter of  FIG. 1  showing the anvil closed against the cartridge and the anvil cap raised from the cavity of the anvil. 
       FIG. 8  is a section view taken along line  8 — 8  of  FIG. 7  depicting the anvil cap raised from the cavity of the anvil. 
       FIG. 9  is a side elevation view, partially in section, of the shaft of the linear cutter of  FIG. 1  showing the anvil opened away from the cartridge and the anvil cap raised from the cavity of the anvil. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  shows a surgical device  78  for manipulating tissue. Surgical device  78  has a first and a second jaw, and one of the jaws is equipped with an expandable member according to an embodiment of the invention. In the embodiment shown in  FIG. 1 , the expandable member is an anvil cap  10 . Anvil cap  10  is shown on one of the jaws, anvil  22 , which is closed adjacent to a second jaw, or cartridge  60 . Cartridge  60  contains staples  61  ( FIG. 2 ), which can be ejected into tissue to be formed into shape to join and retain the tissue by pockets within anvil  22 . Anvil  22  and cartridge  60  are located at a distal end  19  of an elongated shaft  18 . Shaft  18  in the embodiment depicted further comprises a tube  64  extending along a longitudinal axis  27  proximally towards a rotation knob  73  and a handle  76 . Handle  76  attaches at a proximal end  23  of shaft  18 . Right thumbpad  42  and left thumbpad  44  extend from shaft  18 , as an expander actuator, to be grasped by a physician to expand anvil  22 , as will be shown. 
   In the embodiment depicted in  FIG. 1 , surgical device  78  is an endoscopic linear cutter. An endoscopic cutter suitable for modification with the addition of anvil cap  10  could be one described in U.S. Pat. No. 5,597,107 issued to Bryan Knodel et al, on Jan. 28, 1997, and which is hereby incorporated herein by reference. Handle  76  can be the handle of the endoscopic linear cutter described in U.S. Pat. No. 5,597,107, and contains actuators to move portions of shaft  18 . A closure actuator  41  within handle  76  can move tube  64  to drive anvil  22  to positions next to and away from cartridge  60 . A firing actuator  47  within handle  76  can be used to eject staples  61  into tissue. 
     FIG. 2  shows an exploded isometric view of a shaft  18  of surgical device  78 . Anvil cap  10  is a substantially rigid member used to stiffen anvil  22 . Anvil cap  10  is a roughly “U” shaped device having a horizontal section  14  and two vertical sections  16 . Anvil cap  10  has the inside of the “U” shape open towards anvil  22  and three diagonal cap slots  12 , cut into each vertical section  16 . The length of each cap slot  12  extends at a diagonal to longitudinal axis  27  ( FIG. 1 ) of shaft  18 . The distal portion of each cap slot  12  is closer to the closed, section of the “U” than the proximal portion. A bulge  20  rises on vertical section  16  next to each cap slot  12 , along the narrow material edge of the open side of the “U.” 
   Cavity  24  receives anvil cap  10  into anvil  22 . A linkage  32  extends through the center of cavity  24 . Linkage  32  has three anvil holes  36  to align with cap slots  12 , and also provides a linkage hole  38  at a proximal end. Linkage actuator  34  attaches at linkage hole  38  using, for example, a pin, and extends proximally through shaft  18  to a thumbpad hole  46  at the proximal end of linkage actuator  34 . Linkage  32  can rotate relative to linkage actuator  34  about linkage hole  38  to facilitate rotational motion of anvil  22 . 
   Channel  48  carries anvil  22  with assembled anvil cap  10 , linkage  32  and linkage actuator  34 . Channel  48  also carries a knife  65  and a wedge driver  63 . Curvilinear slots  50  retain anvil bosses  52  to locate anvil  22 . Anvil bosses  52  are free to translate along the curve of curvilinear slots  50 . Two “Z” shaped channel thumbpad slots  56  are located near the proximal end of Channel  48 , and at its distal end, channel  48  has a cartridge retention area  58 . 
   Cartridge  60  assembles to cartridge retention area  58 . Cartridge  60  supplies staples  61  and staple drivers (not shown) to surgically staple tissue. Firing wedge  62  travels through openings (not shown) within cartridge  60 , forcing staple drivers towards the tissue surface and forcing staples  61  into tissue. 
   Tube  64  encloses the proximal end of channel  48 , linkage actuator  34 , and the proximal end of linkage  32 . An indentation  66  in tube  64  near the distal end of tube  64  fits into groove  68  on anvil  22 . Tube thumbpad slots  70  are near the proximal end of tube  64  and have a roughly “L” shaped configuration. 
   Right thumbpad  42  and left thumbpad  44  are assembled using a rod  74  and a male thread (not shown) on one thumbpad extending into a female thread within the opposite thumbpad. Rod  74  may alternatively be on either right thumbpad  42  or left thumbpad  44 . Rod  74  is depicted on left thumbpad  44  in  FIG. 2 . Rod  74  of left thumbpad  44  extends through tube thumbpad slots  70 , channel thumbpad slots  56 , and thumbpad hole  46 . Both tube thumbpad slots  70  and channel thumbpad slots  56  fit loosely enough to rod  74  to allow travel of rod  74  along the length of the respective slots. Knob groove  72  keys tube  64  to an adjustment knob  73  ( FIG. 1 ) so that rotation of adjustment knob  73  rotates shaft  18 . 
     FIG. 3  depicts further detail of one of tube thumbpad slots  70 . The roughly “L” shaped configuration is inverted, with the horizontal portions  81  of the “L” nearer the top of tube  64 . Vertical portions  82  extend perpendicular from the proximal parts of horizontal portions  81 . Vertical portions  82  are shown bounded by distal walls  84  and proximal walls  83 . 
   Further detail of anvil  22  is depicted in  FIG. 4 . Two ribs  26  within cavity  24  fit inside the open portion of the inverted “U” shape of anvil cap  10  to locate anvil cap  10 . Anvil slots  30  in anvil  22  align with cap slots  12  when anvil cap  10  is within cavity  24 . Anvil pins  40  ( FIG. 2 ) align with and extend through anvil slots  30 , anvil holes  36 , and cap slots  12 . Anvil pins  40  may press through anvil holes  36  in linkage  32 . Anvil pins  40  have clearance to move proximally and distally within anvil slots  30 . Anvil pins  40  also have clearance to move along the length of diagonal cap slot  12 . 
     FIG. 5  is a side elevation view, partially in section, of shaft  18 . In  FIG. 5 , the configuration of shaft  18  is that of  FIG. 1  with anvil  22  closed and anvil cap  10  within cavity  24 . On the base of cavity  24 , six depressions  28  exist to receive bulges  20  when anvil cap  10  is lowered into cavity  24 . It can also be seen that linkage actuator  34 , left thumbpad  44 , and right thumbpad  42  are moved distally within horizontal portions  81 . Linkage actuator  34  will force linkage  32  distally. Linkage  32  moves anvil pins  40  forward, camming against the bottom portion of cap slots  12  to force anvil cap  10  into cavity  24 . 
     FIG. 5  further shows that anvil  22  has an anvil face  21  opposing a cartridge face  29  when anvil  22  and cartridge  60  are approximated. Additionally, anvil cap  10  possesses an anvil cap back side  55 . A dimension  23 , or height, of the expandable assembly of anvil  22  and anvil cap  10 , can be measured from anvil face  21  to anvil cap back side  55  in a direction perpendicular to longitudinal axis  21 . 
   Channel  48  carries a channel back side  57  opposite cartridge face  29 . An analogous dimension to dimension  23  could be measured from channel back side  55  to cartridge face  29 . 
     FIG. 6  is a cross-sectional view of anvil  22  taken along line  6 — 6  of  FIG. 5 .  FIG. 6  depicts anvil cap  10  recessed within cavity  24  of anvil  22 . With anvil cap  10  recessed into anvil  22 , anvil  22  has a first cross-sectional area and a first area moment of inertia lower than a second cross-sectional area and a second area moment of inertia that can be attained by expanding anvil cap  10  from cavity  24 . The dimension  23 , or height, of anvil  22  is relatively small, and anvil  22  has first stiffness lower than a second stiffness that can be attained by expanding anvil cap  10  from cavity  24 . However, with anvil cap  10  within cavity  24  of anvil  22 , in the position shown in  FIG. 6 , anvil  22  has a low profile easily inserted through a small opening of, for example, a trocar cannula used in endoscopic surgery. 
     FIG. 7  is a side elevation view, partially in section, of shaft  18  with anvil  22  closed to a position adjacent cartridge  60 , and anvil cap  10  moved out of cavity  24 . After inserting shaft  18  through an orifice, the physician can raise anvil cap  10  from cavity  24  by moving either left thumbpad  44  or right thumbpad  42  proximally along horizontal portions  81  of tube thumbpad slots  70  as shown in the figure. Left thumbpad  44  or right thumbpad  42  pulls linkage actuator  34  proximally, and linkage actuator  34  in turn moves linkage  32  proximally. Anvil pins  40  exert a force against cap slots  12  to cam anvil cap  10  away from cavity  24  in a direction perpendicular to longitudinal axis  27 . Anvil cap  10  is restrained from moving proximally by the proximal wall of cavity  24 . After raising anvil cap  10 , the user can move either left thumbpad  44  or right thumbpad  42  in a direction away from horizontal portions  81  and along vertical portions  82 , rotating linkage actuator  34  slightly relative to linkage  32 . Distal walls  84  of tube thumbpad slots  70  restrain left thumbpad  44  and right thumbpad  42  from moving distally, locking anvil cap  10  in the expanded position away from cavity  24 . 
     FIG. 8  is a cross-sectional view of anvil  22  taken along line  8 — 8  of  FIG. 7 .  FIG. 8  shows anvil cap  10  expanded from cavity  24  of anvil  22 . With anvil cap  10  expanded from anvil  22 , anvil  22  has a second cross-sectional area and a second area moment of inertia higher than the first cross-sectional area and the first area moment of inertia that exists when anvil cap  10  is lowered into cavity  24 . The dimension  23 , or height, of anvil  22  has increased, and anvil  22  has a second stiffness higher than the first stiffness that exists when anvil cap  10  is lowered into cavity  24 . The size of anvil  22  has effectively increased in a direction perpendicular to longitudinal axis  27 . Anvil  22 , which had a low profile for easy insertion through a small orifice, now has a higher, stiffer profile for use within a body. 
     FIG. 9  shows a split section view of shaft  18  with anvil  10  moved to an open position away from cartridge  60 . Closure actuator  41  ( FIG. 1 ) of handle  76  moves tube  64  proximally to open anvil  22  by moving anvil  22  rotatably away from cartridge  60 . Pulling tube  64  proximally causes indentation  66  to force anvil  22  proximally by pulling on groove  68 . Anvil  22  rotates to an open position when anvil bosses  52  translate along curvilinear slots  50 . Tube thumbpad slots  70  move with tube  64  proximally relative to channel thumbpad slots  56 . Distal walls  84  on tube  64  urge right thumbpad  42  and left thumbpad  44  proximally through channel thumbpad slots  56 . Right thumbpad  42  and left thumbpad  44  draw linkage actuator  34  and linkage  32  proximally, so that linkage actuator  34  maintains a force on anvil cap  10  through anvil pins  40  and cap slots  12 . The force maintains anvil cap  10  in a position raised from cavity  24  of anvil  22  as anvil  22  is moved from the closed position to an open position. Linkage  32  also rotates relative to linkage actuator to allow rotation of anvil  22  as anvil bosses  52  translate along curvilinear slots  50 . 
   Opened surgical device  78  may now grasp on tissue requiring transection and stapling. Firing actuator  47  ( FIG. 1 ) within handle  76  can move wedge driver  63  distally to force firing wedge  62  through cartridge  61  to eject staples  61 . Pockets in anvil  22  form staples  61  to retain tissue to control bleeding. Knife  65  may be used to transect tissue. 
   After transection and stapling, the user can remove surgical device  78  from the patient&#39;s body through a small orifice. To accomplish removal, the user opens surgical device  78  to unclamp it from any tissue. The user then reverses the procedure depicted in  FIGS. 5 through 9 . Anvil  22  is first closed by moving tube  64  distally. Distal movement of tube  64  causes the proximal walls  83  of tube thumbpad slots  70  to force right thumbpad  42  and left thumbpad  44  distally through channel thumbpad slots  56 . Right thumbpad  42  and left thumbpad  44  move to the distal sections of channel thumbpad slots  56 , where the vertical portions  82  of channel thumbpad slots  56  become available for use. Moving either thumbpad first vertically along vertical portions  82 , then horizontally and distally along horizontal portions  81  after the thumbpads are in the distal position will return the thumbpads to the original position depicted in  FIG. 3  and lower anvil cap  10  into cavity  24 . The closed anvil  22  with retracted anvil cap  10  may now be withdrawn through a smaller orifice that would be possible with expanded anvil  22 . 
   It will be recognized that equivalent structures may be substituted for the structures illustrated and described herein and that the described embodiment of the invention is not the only structure which may be employed to implement the claimed invention. As one example of an equivalent structure that may be used to implement the present invention, the endoscopic linear cutter may be a surgical implement such as a grasper, scissors, or other endoscopic surgical tools. Anvil cap  10  may be a plate that moves alongside an end-effector of a surgical tool instead of recessing into a cavity in the end-effector. 
   While preferred embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. For example, as would be apparent to those skilled in the art, the disclosures herein have equal application in robotic or power assisted surgery. In addition, it should be understood that every structure described above has a function and such structure can be referred to as a means for performing that function. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. Accordingly, it is intended that the invention be limited only by the spirit and scope of the appended claims.