Articulation mechanisms for surgical instrument

[0001] This application is a continuation-in-part of U.S. patent application Ser. No. 12/436,087, filed on May 5, 2009, which is hereby incorporated by reference in its entirety.

[0002] The invention generally relates to an articulated surgical instrument, and more specifically to an articulated surgical stapler.

[0003] Minimally invasive surgery is performed through small incisions in the body, into which trocar ports may or may not be placed. One or more surgical instruments are inserted through each incision in order to perform the surgical procedure. In order to effectuate one of the objectives of minimally invasive surgery, which is the minimization of incisions to the body to reduce healing time and scarring, it is desirable to minimize the number of incisions made in the body. The number of incisions and their placement are determined by the particular surgical procedure to be performed and the configuration of the instruments used to carry out that procedure.

[0004] One problem encountering during the performance of a minimally invasive surgical procedure is access to the tissue to be treated. Depending on the specific anatomy of the patient, it may be difficult to reach an area to be treated with a specific surgical instrument. As a result, one or more additional incisions may need to be made in the patient in order to access that tissue. Or, the surgeon may need to obtain a different surgical instrument, adding to the time and expense of the procedure. Additionally, where more incisions may be made or additional instruments may be utilized, it can be difficult and/or time-consuming for the surgeon to find the surgical site again.

[0022] The use of the same reference symbols in different figures indicates similar or identical items.

[0023] U.S. patent application Ser. No. 11/851,379, filed Sep. 6, 2007; U.S. patent application Ser. No. 11/956,988, filed Dec. 14, 2007; U.S. patent application Ser. No. 12/263,171, filed Oct. 31, 2008; and U.S. patent application Ser. No. 12/436,014, filed May 5, 2009 (the “Endocutter Documents”) are hereby incorporated by reference herein in their entirety. U.S. patent application Ser. No. 12/400,760, filed Mar. 9, 2009 (the “Articulation Document”) is also hereby incorporated by reference herein in its entirety.

[0024] Surgical Instrument

[0025] Referring to FIG. 1, a surgical instrument 1 includes a handle 2 attached to a shaft 4, which in turn is attached to an end effector 6. The surgical instrument 1 may be an endocutter, a linear cutter, a stapler, or any other suitable surgical instrument. The end effector 6 may be one or more separate components that are connected to the shaft 4, or may be fabricated integrally with the distal end of the shaft 4. As discussed in greater detail below, the end effector 6 may be fixed to the shaft 4, or may be separable from the shaft 4 such that a fresh end effector 6 may be attached to the shaft 4 after one or more actuations of the surgical instrument. The end effector 4 and at least the distal end of the shaft 4 may be sized to pass through an incision or through a standard trocar port that may be placed in the patient. Advantageously, the end effector 4 may be sized to pass through a trocar port, having an opening between 5-10 millimeters in diameter. Alternately, the surgical instrument 1 may be used in the course of conventional open surgery, where a trocar port is not used. The end effector 4 may include a staple holder 8 connected to an anvil 10, and may be movable between an open configuration and a closed configuration. In the closed configuration, tissue may be clamped between the staple holder 8 and the anvil 10. Alternately, the end effector 4 may omit the anvil 10. Alternately, the end effector 4 need not include a staple holder 8 or anvil 10, and the end effector 4 may instead be a different surgical instrument, such as but not limited to a bipolar cutter, a biopsy device, a grasper, or a stabilizer.

[0026] The shaft 4 advantageously has a tubular shape with a lumen defined therein. Optionally, the shaft 4 may include a cutaway, trough or other feature (not shown) to allow a guidewire (if any) or other positioning aid that may be used in the surgical procedure to remain in place during actuation of the surgical instrument 1. The shaft 4 may be flexible or rigid, in whole or in part. The shaft 4 may be articulated in at least one location, if desired. Referring to FIG. 2, as one example, the shaft 4 may be generally rigid, with the exception of a flexible articulated region 12 that connects two generally-rigid segments of the shaft 4. The articulated region 12 may be configured and operated substantially as set forth in the Articulation Document. As an example of an articulated region 12, a plurality of slots 14 may be located in the shaft 4 in the articulated region 12. The slots 14 may extend completely through the wall of the shaft 4 from the outer surface of the shaft to the lumen in the shaft 4. The slots 14 may be arranged in any suitable manner. As one example, each slot 14 may extend along greater than 180 degrees of circumference of the shaft 4, between two vertices 15. Proceeding proximally along the shaft 4, at least two slots 14 may be generally arranged in an alternating manner. That is, one slot 14 may open generally in one direction away from the longitudinal centerline of the shaft 4, and the slot 14 proximal to that may open generally in the opposite direction away from the longitudinal centerline of the shaft 4. To accomplish this, the vertices 15 of a slot opening (for example) laterally to the left may be located laterally to the right of the vertices of a longitudinally adjacent slot opening laterally to the right. As a result, where at least two slots 14 extend along greater than 180 degrees of circumference of the shaft 4, no line on the surface of the shaft 4 that is parallel to the longitudinal centerline of the shaft 4 can extend completely through the articulating region 12 without encountering a slot 14. Put another way, every line on the surface of the shaft 4 that is parallel to the longitudinal centerline of the shaft 4 crosses at least slot 14. The slots 14 may be oriented and arranged relative to one another to provide for lateral articulation of the shaft 4. That is, the slots 14 may be oriented and arranged such that the portion of the shaft 6 distal to the articulating region 12 is rotatable in a single plane, laterally left and right. Alternately, the slots 14 may be oriented and arranged such that the portion of the shaft 6 distal to the articulating region 12 is rotatable in a single plane in a direction other than laterally left and right. Alternately, the slots 14 may be oriented and arranged such that the portion of the shaft 6 distal to the articulating region 12 is rotatable in more than a single plane.

[0027] Referring also to FIGS. 3-4, one example of an articulation insert 20 is shown. The articulation insert 20 is placed inside the lumen of the shaft 4, such that at least part of the articulation insert 20 is located in the articulating region 12 of the shaft 4. The articulation insert 20 may be fixed to the shaft 4 along part or all of its length. Alternately, the articulation insert 20 may be movable relative to the lumen of the shaft 4 along at least part of its length. The articulation insert 20 of FIG. 3 is a flexible, unitary solid, fabricated from any suitable material. As one example, at least part of the articulation insert 20 may be fabricated from or coated with polytetrafluoroethylene (PTFE). Alternately, at least part of the articulation insert 20 may be coated with any lubricious material, such as, for example, sodium stearate. Alternately, the articulation insert of FIG. 3 may have two or more separate, independent sections. At least one passage 22 is defined longitudinally through the articulation insert 20. The passages 22 may be arranged such that the articulation insert 20 is bilaterally symmetrical about two different perpendicular planes. In this way, at least part of the articulation insert 20 is bendable in a direction away from the longitudinal axis of the articulation insert 20 in the straight configuration shown in FIG. 1, without a preferred bending direction of the articulation insert 20 being established. In such a configuration, at least one of the passages 22 may be empty. Alternately, the articulation insert 20 may be bilaterally symmetrical about only a single plane, or may be asymmetrical.

[0028] Each passage 22 may have any suitable cross-sectional shape. The cross-sectional shape of each passage 22 may be substantially constant along its length, or may vary along at least part of its length. Two or more passages 22 may connect with one another at one or more points along their length. Referring also to FIG. 4A, at least one of the passages 22 is sized and shaped to receive a feeder belt 30 therethrough, where staples 32 are fixed to and frangibly separable from that feeder belt 30. The feeder belt 30 and staples 32 may be substantially as described in the Endocutter Documents. At least one passage 22 may include two staple passages 24 in which the staples 32 of the feeder belt 30 are received, separated by a generally T-shaped platform 26. The top 34 of the T-shaped platform 26 is narrow enough to receive the corresponding feeder belt 30 on its surface, such that the feeder belt 30 is slidable along the top 34 of the T-shaped platform. The top 34 of the T-shaped platform 26 is also wider than the column 36 underneath, which may be undercut relative to the top 34 of the T-shaped platform 26. The narrower column 36 allows the staples 32 room to move as the articulation insert 20 bends, as described in greater detail below. Alternately, the T-shaped platform 26 may have any other suitable shape. As one example, it may be V-shaped, where the wider end of the V is the top 34 on which a feeder belt 30 slides. One or more additional passages 38 may be provided through the articulation insert 20, such that a control member or other structure or mechanism can pass from the handle 2 along the shaft 4 through the passage or passages 38 to the end effector 6.

[0029] Referring also to FIGS. 11-13, an articulation insert 20 may include two or more segments 70. At least one segment 70 may be longitudinally slidable relative to at least one other segment 70. The longitudinal direction is the direction substantially perpendicular to the page. (Given that the shaft 4 can bend in the articulating region 12, the longitudinal direction can also bend within the articulating region 12.) Each segment 70 may be solid and substantially continuous along its length. Advantageously, each segment 70 is independently slidable relative to one or more other segments 70. Such independent motion allows the segments 70 to slip longitudinally relative to one another, reducing stress that would otherwise be experienced by the articulation insert 20 upon bending of the articulated region 12. That is, each segment 70 has a different moment of inertia than a comparative single-piece articulation insert 20 such as described above with regard to FIGS. 1-4. As a result, bending of the articulated region 12 may require less force, thereby further reducing stress that otherwise would be experienced by the articulation insert 20 during bending of the articulating region 12. Each segment 70 may be fabricated from, and/or at least partially coated with, a lubricious material such as PTFE. As another example, at least one segment 70 may be connected to another segment 70 along a least a part of its length, such that those connected segments 70 are not independent from one another. In this way, some slippage between connected segments 70 remains possible.

[0030] At least one segment 70 may be positioned radially outward from a least one other segment 70. For example, referring to FIG. 11, one segment 70 may be a substantially cross shaped segment 72 with four arms 74 extending radially outward from the center 76 of the cross shaped segment 72. Optionally, the longitudinal center line of the articulation insert 20 may pass through the center 76 of the cross-shaped segment 72. The articulation insert 20 may include four other segments 70, where each segment 70 is positioned between two of the arms 74. Each segment 70 may slip longitudinally relative to the cross-shaped segment 72. Each of those segments 70 are positioned radially outward from the center 76 of the cross-shaped segment 72. As another example, referring to FIG. 13, one segment 70 may be a substantially bar-shaped segment 78. Optionally, the longitudinal center line of the articulation insert 20 may pass through the center 76 of the bar-shaped segment 78. The articulation insert 20 may include two other segments 70, where each segment 70 may be generally semicircular in cross section. Each segment 70 may be located on a different side of the bar-go shaped segment 78. Each segment 70 may slip longitudinally relative to the bar-shaped segment 78.

[0031] Referring to FIGS. 11 and 13, the passages 22 through the articulation insert 20 may be configured such that at least part of at least one passage 22 that is configured to receive a feeder belt 30 therein may be bounded by at least two adjacent segments 70. For example, with reference to FIG. 11, each passage 22 is generally U-shaped, where one leg 78 of and the base of the U are bounded by two adjacent segments 70, and the other leg 80 of the U is defined completely within one of the segments 70. As another example, with reference to FIG. 13, each passage 22 is generally U-shaped, where one leg 78 of the U is bounded by two adjacent segments 70, and the base of the U and the other leg 80 of the you is defined completely within one of the segments 70. Alternately, at least one passage 22 may be bounded by more or fewer segments 70, along part or all of its length. Referring to FIG. 12, the passages 22 through the articulation insert 20 instead may be configured such that at least one passage 22 that is configured to receive a feeder belt 30 therein is defined completely through a single segment 70. Optionally, all of the passages 22 that are configured to receive a feeder belt 30 therein each are defined completely through a separate segment 70. Alternately, two or more of the passages 22 that are configured to receive a feeder belt 30 therein are defined in a single segment 70.

[0032] As another example, more than one articulation insert 20 may be used. At least two of the articulation inserts 20 may be positioned end to end. That is, at least two of the articulation inserts 20 may be positioned sequentially in the longitudinal direction. At least two successive articulation inserts 20 may be spaced apart from one another. However, any two successive articulation inserts 20 may be in contact with one another. Where more than one articulation insert 20 is used, at least one articulation insert 20 may be shorter in the longitudinal direction than the articulation insert 20 described in FIGS. 1-4. Alternately, one or more of the articulation inserts 20 are the same length for longer than the articulation insert 20 described in FIGS. 1-4. The articulation inserts 20 may extend within the shaft 4 proximally and/or distally relative to the articulating region 12. Alternately, the plurality of articulation inserts 20 may be generally confined to the articulating region 12. Each articulation insert 20 may be held in place in any suitable manner, although at least one articulation insert 20 may be free to slide at least a limited amount within the lumen of the shaft 4.

[0033] Referring to FIGS. 5-10, another example of an articulation insert 20 is shown. The articulation insert 20 is placed inside the lumen of the shaft 4, such that at least part of the articulation insert 20 is located in the articulating region 12 of the shaft 4. The articulation insert 20 may be fixed to the shaft 4 along part or all of its length. Alternately, the articulation insert 20 may be movable relative to the lumen of the shaft 4 along at least part of its length. The articulation insert 20 of FIGS. 5-10 is fabricated from multiple individual inserts 40 flexibly connected together, and may be referred to as the accordion configuration. Each individual insert 40 may be a thin, generally circular plate. Alternately, one or more individual inserts 40 may have a different shape, thickness or configuration. Advantageously, the inserts 40 are rigid. Alternately, at least one insert 40 is at least partly flexible.

[0034] Advantageously, the individual inserts 40 include cutouts defined therein that collectively define passages 22 of similar shape and size as the cross-section of the flexible solid of FIGS. 3-4, such that the shape of the cutouts are substantially the same as set forth above with regard to FIGS. 3-4. At least one passage 22 may include two staple passages 24 in which the staples 32 of the feeder belt 30 are received, separated by a wall 42. The wall 42 may include a wide area 44 at its top, narrowing generally angularly to a narrow strut 46 that connects to a wider, lower portion 48 of the wall 42. A rail 50 may extend between the individual inserts 40, connected to the upper portion of each wall 42. The rail 50 may include a cavity having substantially the opposite shape of the wide area 44 and the strut 46 of the wall 42, such that the rail 50 is held securely on top of the wall 42. Advantageously, each rail 50 is slidable in the direction perpendicular to the page with regard to FIG. 5 relative to the corresponding wall 42, as described in greater detail below. Alternately, at least one rail 50 may be fixed to at least one wall 42. The top 52 of the rail 50 is narrow enough to receive the corresponding feeder belt 30 on its surface, such that the feeder belt 30 is slidable along the top 52 of the rail 50. The top 52 of the rail 50 is also wider than the wall 42 underneath, which allows the staples 32 room to move as the articulation insert 20 bends, as described in greater detail below. The combination of the rail 50 and the wall 42 is generally T-shaped in cross-section.

[0035] At least one flexible beam 60 may be fixed to each of the individual inserts 40. The beam or beams 60 may thus provide spacing between the individual inserts 40 and hold them in a desired orientation. Alternately, at least one beam 60 is not fixed relative to at least one individual insert 40, such that relative motion therebetween is allowed. The beam or beams 60 may be fabricated from any suitable material. Optionally, successive individual inserts 40 may be separated by O-rings (not shown) or other cushioning material. If so, the O-rings or other cushioning material are either located outside of the passages 22, or include apertures or passages therein aligned with the passages 22 to allow each feeder belt 30 to move through the corresponding passage without interference.

[0036] Referring to FIG. 6, the articulation insert 20 is in a configuration in which its longitudinal centerline is substantially straight. This configuration is advantageously the neutral state of the articulation insert 20, which is the configuration assumed by the articulation insert 20 when no external forces are acting upon it. In the neutral state, the individual inserts 40 may be substantially parallel to one another, and the beam or beams 60 and rail or rails 50 may be substantially perpendicular to the individual inserts 40. Alternately, at least one individual insert 40 may be configured or oriented differently in the neutral state, and/or at least one beam 60 or rail 50 may be configured or oriented differently in the neutral state. Alternately, the articulation insert 20 may be in its neutral state when it is curved such as shown in FIG. 7. Referring to FIG. 8, at least one rail 50 may be longer than the remainder of the articulation insert 20 in the neutral state, such that the distal end of that rail 50 extends distal to the most-distal individual insert 40, the proximal end of that rail 50 extends proximal to the most-proximal individual insert 40, or both. Optionally, one rail 50 extends distal to a remainder of the articulation insert 20, and the other rail 50 extends proximal to a remainder of the articulation insert 20.

[0037] Operation

[0038] The end effector 6 of the surgical instrument 1 is introduced into the body of the patient such as described in the Endocutter Documents and the Articulation Document. The end effector 6 may be articulated such as described in the Articulation Document, before and/or after introduction of the end effector 6 into the patient. Bending of the shaft 4 is focused in and substantially restricted to the articulated region 12. As a consequence of bending of the articulated region 12, the articulation insert 20 is bent as well. Alternately, articulation may be caused by manipulating the articulation insert 20 to in turn cause bending of the articulated region 12 of the shaft 4. The articulated region 12 may be configured to bend through a known range of motion.

[0039] As the articulated region 12 bends, the articulation insert 20 bends. Where the articulation insert 20 has the accordion configuration of FIGS. 5-10, the rails 50 advantageously slide relative to the corresponding walls 42 of the passages 22. In this way, the upper surface 52 of each rail 50 remains substantially flat, because the rails 50 are not compressed or expanded as the articulated insert 20 bends, but rather are free to slide relative to the individual inserts 40. As seen in FIGS. 7 and 10, bending of the articulation insert 20 may cause at least one end of at least one rail to slide outward from a remainder of the articulation insert. As the articulated region 12 bends, where the articulation insert 20 is a flexible solid, the free ends of the staples 32 in a passage 22 on one side of each T-shaped platform 26 move under the top 34 of that T-shaped platform 26 into the space provided by the narrower column 36, substantially without interfering with the T-shaped platform 26. As the articulated region 12 bends, where the articulation insert 20 has an accordion configuration, the free ends of the staples 32 in a passage on one side of each wall 42 move under the rail 50 into the space provided by the narrow wall 42 as compared to the rail 50, substantially without interfering with the wall 42. Thus, each exemplary articulation insert 20 facilitates bending of the feeder belt 30 without prematurely bending the staples 32.

[0040] Where O-rings or other cushioning material is provided between successive individual inserts 40 of the articulation insert 40, the bending of the articulated insert 40 compresses a portion of each O-ring or other material between successive individual inserts 40. In this way, separation between those successive individual inserts 40 may be more easily maintained.

[0041] The surgical instrument 1 may then actuate the end effector 6 such as set forth in the Endocutter Documents and the Articulation Document. If the surgeon desires to use the end effector 6 at a different location within the patient, and the surgical instrument 1 includes one or more feeder belts, as described in the Endocutter Documents, the feeder belt or belts 30 may be advanced, placing a fresh set of staples in position for deployment within the staple holder. Such advancement may be accomplished as set forth in the Endocutter Documents. Where the articulation insert 20 is a flexible solid, each feeder belt 30 slides along the top 34 of the corresponding T-shaped platform 26. Optionally, the top 34 may be lubricated with any lubricious material or coating, such as PTFE, or the T-shaped platform 26 may be fabricated from a lubricious material. The width of the top 34 of the T-shaped platform 26 as compared to the column 36 prevents the staples 32 from colliding with the column 36, such that the feeder belt 30 can advance. The narrowness of the column 36 advantageously is selected based on the range of motion of the articulated region 12, such that the feeder belt or belts 30 can be advanced regardless of the degree of articulation of the end effector 6. Alternately, the end effector 6 must first be moved to a lesser degree of articulation before advancing the feeder belt or belts 30. Where the articulation insert has an accordion configuration, each feeder belt 30 slides along the top 52 of the corresponding rail 50. Optionally, the top 52 may be lubricated with any lubricious material or coating, such as PTFE, or the rail 50 may be fabricated from a lubricious material. The width of the rail 50 as compared to the wall 48 prevents the staples 32 from colliding with the wall 48, such that the feeder belt 30 can advance. The narrowness of the wall 48 advantageously is selected based on the range of motion of the articulated region 12, such that the feeder belt or belts 30 can be advanced regardless of the degree of articulation of the end effector 6. Alternately, the end effector 6 must first be moved to a lesser degree of articulation before advancing the feeder belt or belts 30.

[0042] Referring to FIGS. 1 and 14, the shaft 4 that connects the handle 2 to the end effector 6 may be flaccid. As used in this document, the term “flaccid” refers to a shaft 4 that is flexible but inelastic, such that the shaft 4 is not biased to any particular position, but instead remains in whatever position results from the application of external force thereto. As described above, the feeder belt 30 may extend into and/or completely through the lumen of the flaccid shaft 4. Where the flaccid shaft 4 is utilized, the active articulation mechanism of the Articulation Document may be omitted. Instead, a forceps, robotic end effector, or other tool, or the user's hand, is used to grasp the end effector 8 and/or the distal end of the flaccid shaft 4 in order to orient the end effector 8 in the desired orientation. The shaft 4 flexes in response to that placement of the end effector 8, rather than causing the placement of the end effector 8. A surgical instrument 1 using such a flaccid shaft 4 otherwise may be operated substantially as described above. Such a flaccid shaft 4 may bend at any point along its length, and therefore need not include a dedicated articulating region 12. The shaft 4 optionally may be rigid along part of its length, and flaccid along another part of its length.

[0043] As set forth in the Endocutter Documents, staples extending from the feeder belt 30 may be organized into groups separated by blank space, where that blank space may have any suitable length. Advantageously, no staples extend from, or into an area bounded by, the blank space of the feeder belt 30. Optionally, where a blank space is provided, that blank space may be configured to facilitate articulation of the shaft 4. Referring to FIG. 15, at least part of at least one blank space 90 on the feeder belt 30 may be laterally necked down such that its width is less than the width of the feeder belt 30 immediately proximal and/or distal to the blank space 90. Alternately, at least part of at least one blank space 90 on the feeder belt 30 may also, or instead, be reduced in thickness compared to the thickness of the feeder belt 30 immediately proximal and/or distal to the blank space 90. Referring to FIG. 16, at least part of at least one blank space 90 may be twisted. The twist may be substantially along the longitudinal centerline of the feeder belt 30, or may be about a different line or lines. Referring to FIG. 17, at least part of at least one blank space 90 may be a flexible link 92 that may extend out-of-plane relative to the feeder belt 30 immediately proximal and/or distal to that flexible link 92.

[0044] The shaft 4 and order the articulating region 12 may be configured to move between a straight configuration, in which the longitudinal centerline of the shaft 4 is substantially a straight line, and an articulated configuration, in which a portion of the shaft 4 is angled or curved relative to a remainder of the shaft 4. If so, at least one feeder belt 30 may be configured to advance solely when the shaft 4 is in the straight configuration. This may be accomplished by controlling the motion of the feeder belt or belts 30 with the handle 2, such as by the use of a lockout that prohibits actuation of the handle 2 to advance one or more feeder belts 30 when the shaft 4 is in anything but the straight configuration.

[0045] Alternately, the shaft 4 (whether flaccid or articulated) may bend in such a way that at least one feeder belt 30 is plastically deformed during motion of the shaft 4 from the straight configuration to the articulated configuration. At least one staple fixed to the shaft 4 may bend out of its initial shape during that plastic deformation of the feeder belt 30. Upon motion of the shaft 4 back to the straight configuration, at least one feeder belt 30 may be plastically deformed back to its initial shape, and at least one staple may also bend back to its initial shape.

[0046] While the invention has been described in detail, it will be apparent to one skilled in the art that various changes and modifications can be made and equivalents employed, without departing from the present invention. It is to be understood that the invention is not limited to the details of construction, the arrangements of components, and/or the method set forth in the above description or illustrated in the drawings. For example, the articulation insert 20 may be used to pass mechanisms and/or structures through an articulating region 12 of a shaft 4 other than a feeder belt 30 and/or staples 32. Statements in the abstract of this document, and any summary statements in this document, are merely exemplary; they are not, and cannot be interpreted as, limiting the scope of the claims. Further, the figures are merely exemplary and not limiting. Topical headings and subheadings are for the convenience of the reader only. They should not and cannot be construed to have any substantive significance, meaning or interpretation, and should not and cannot be deemed to indicate that all of the information relating to any particular topic is to be found under or limited to any particular heading or subheading. Therefore, the invention is not to be restricted or limited except in accordance with the following claims and their legal equivalents.