Feeder belt for true multi-fire surgical stapler

[0001] This application claims priority to U.S. Provisional Patent Application Ser. No. 61/175,027, filed on May 3, 2009, which is herein incorporated by reference in its entirety.

[0002] The invention generally relates to surgical staplers and stapling.

[0003] An endocutter is a surgical tool that staples and cuts tissue to transect that tissue while leaving the cut ends hemostatic. An endocutter is small enough in diameter for use in minimally invasive surgery, where access to a surgical site is obtained through a trocar, port, or small incision in the body. A linear cutter is a larger version of an endocutter, and is used to transect portions of the gastrointestinal tract. A typical endocutter receives at its distal end a disposable single-use cartridge with several rows of staples, and includes an anvil opposed to the cartridge. During actuation of an endocutter, the cartridge fires all of the staples that it holds. In order to deploy more staples, the endocutter must be moved away from the surgical site and removed from the patient, after which the old cartridge is exchanged for a new cartridge. The endocutter is then reinserted into the patient. However, it can be difficult and/or time-consuming to located the surgical site after reinsertion. Further, the process of removing the endocutter from the patient after each use, replacing the cartridge, and then finding the surgical site again is tedious, inconvenient and time-consuming, particularly where a surgical procedure requires multiple uses of the endocutter.

[0004] In order to overcome these difficulties, Cardica, Inc. of Redwood City, Calif. has developed a true multi-fire endocutter that is capable of firing multiple times without the need to utilize single-use-cartridges. That endocutter is described in, for example, U.S. patent application Ser. No. 12/263,171, filed on Oct. 31, 2008 (the “Endocutter Application”), which is hereby incorporated by reference in its entirety. Referring to FIG. 1, the Endocutter Application, among other items, discloses a feeder belt 2 to which a plurality of staples 4 are frangibly attached. The feeder belt 2 bends around a pulley 6 at its distal end. Each end of the feeder belt 2 is connected to a different rigid, toothed rack 8, and each rack engages a gear 10. The racks 8 are rigid, and as a result advancement of one rack 8 causes the gear 10 to rotate and thereby move the other rack 8 in the opposite direction. The gear 10 is located in a shaft 12 of the tool, between the handle and a distal end of the shaft. Because the racks 8 are rigid, the linear travel of the racks 8 is limited by the length of the shaft 12 and of the handle connected to the shaft. Consequently, the number of firings that can be made by the tool is limited by the linear distance that the racks 8 can travel within the shaft 12 and structure connected to the shaft 12.

[0010] The use of the same reference symbols in different figures indicates similar or identical items.

[0011] Continuous Feeder Belt Assembly with Flexible Rack

[0012] Referring to FIG. 2, a feeder belt 2 bends around a pulley 6 at its distal end, such that an upper portion 14 of the feeder belt 2 is above and spaced apart from a lower portion 16 of the feeder belt 2. The upper portion 14 and lower portion 16 of the feeder belt 2 may be, but need not be, substantially parallel to one another. The upper portion 14 and lower portion 16 of the feeder belt 2 each have a proximal end, and the proximal end of each portion 14, 16 may be connected to a flexible rack 18. That is, the feeder belt 2 is connected at each end to a flexible rack 18. The combination of the feeder belt 2 and the flexible rack 18 may be referred to as the belt assembly 20. The belt assembly 20 is continuous, meaning that the belt assembly 20 defines a continuous, unbroken loop. The flexible rack 18 may be flexible in any suitable manner. As one example, the flexible rack 18 may be made from a flexible material with sufficient strength and other material properties to allow it to bend around the gear 10, and to be attached to and exert tension on the feeder belt 2. As another example, the flexible rack 18 may be a chain or other mechanism with individual, small links that are themselves rigid but that are collectively flexible. As another example, the flexible rack 18 may be fabricated from nickel-titanium alloy or other superelastic material.

[0013] Where the flexible rack 18 is utilized, the gear 10 may be located at the proximal end of the continuous belt assembly 20. In this way, the gear 10 may be utilized to tension the feeder belt 2 between the gear 10 and the pulley 6 at the distal end of the feeder belt 2. If so, the gear 10 may be located at or near the proximal end of the shaft 12, which may be held within a handle 24, or may be located proximal to or outside the shaft 12 inside the handle 24 or other structure attached to the shaft 12. Further, the initial position of the feeder belt 2 may be as shown in FIG. 2, where staples 4 extend from the upper portion 14 of the feeder belt 2 along substantially all of the upper portion 14. In this way, the feeder belt 2 is able to include more staples 4 along its length than the feeder belt 2 of FIG. 1, such that more staple firings can be made with a single feeder belt 2.

[0014] The feeder belt 2 may be assembled into an endocutter or other surgical apparatus, and may be actuated by that endocutter or other surgical apparatus, substantially as described in the Endocutter Application. Optionally, the gear 10 may be directly driven by a handle such as described in the Endocutter Application, thereby reducing the number of parts and simplifying the overall assembly relative to that handle.

[0015] Optionally, referring also to FIG. 3, staples 4 may be frangibly connected to the flexible rack 18 as well as to the feeder belt 2. The staples 4 may be connected to the flexible rack 18 in substantially the same manner as described in the Endocutter Application. Alternately, the staples 4 may be connected to the flexible rack 18 in any other suitable manner. Where staples 4 are carried by the flexible rack 18, the upper portion 14 of the feeder belt 2 may be spaced apart from the lower portion 16 of the feeder belt 2 a distance sufficient that the staples 4 extending from each portion 14, 16 do not interfere with or engage one another. Alternately, the staples 4 instead, or also, may be laterally spaced relative to one another, such that in the initial position of the feeder belt 2, the staples 4 extending from the upper portion 14 of the continuous belt assembly 20 are laterally spaced a first distance from a longitudinal centerline of that continuous belt assembly 20, and the staples 4 extending from the lower portion 16 of the continuous belt assembly 20 are laterally spaced a second distance from a longitudinal centerline of that continuous belt assembly 20, where the first distance and the second distance are sufficiently different from one another that the staples 4 extending from different portions 14, 16 pass by one another without colliding or interfering with one another during actuating of the continuous belt assembly 20. That is, the continuous belt assembly 20 is arranged in any suitable manner such that the staples 4 along the feeder belt 2 and the flexible rack 18 of the continuous belt assembly 20 do not interfere with one another.

[0016] Alternately, where staples 4 extend from the flexible rack 18, the feeder belt 2 may be omitted, such that the flexible rack 18 is continuous and holds and deploys all of the staples 4.

[0017] Rackless Continuous Feeder Belt Assembly

[0018] Referring to FIG. 4, a feeder belt 2 such as described in the Endocutter Application may include a plurality of apertures 26 defined therein. The apertures 26 may be sized, shaped and spaced apart from one another such that they engage teeth on the gear 10. The feeder belt 2 is sufficiently flexible to wrap around and be driven around the pulley 6, and consequently is sufficiently flexible to wrap around and be driven by or around the gear 10. In such an embodiment, the rack or racks 8, 18 may be omitted, and the feeder belt 2 is itself continuous and forms a continuous loop, as shown in FIG. 5. Alternately, the apertures 26 may be omitted, and the underside of the feeder belt 2 may include teeth similar to one of the racks 8, 18 configured to engage the gear 10. Alternately, the apertures 26 may be omitted, and the feeder belt 2 may be held in tension or otherwise manipulated such that the flat feeder belt 2 is capable of being advanced without the use of features on the feeder belt 2 configured to engage a gear, or without the use of a rack 8, 18 connected to or otherwise engaging the feeder belt 2.