Patent Description:
In certain types of surgical procedures, the use of surgical staples has become the preferred method of joining tissue and, as such, specially configured surgical staplers have been developed for these applications. For example, intra-luminal or circular staplers have been developed for use in a surgical procedure known as an anastomosis. Circular staplers useful for performing an anastomosis are disclosed, for example, in <CIT>; <CIT>; <CIT>; and <CIT>.

One form of an anastomosis comprises a surgical procedure wherein sections of intestine are joined together after a diseased portion has been excised. The procedure requires re-joining the ends of the two tubular sections together to form a continuous tubular pathway. Previously, this surgical procedure was a laborious and time consuming operation. The surgeon had to precisely cut and align the ends of the intestine and maintain the alignment while joining the ends with numerous suture stitches. The development of circular staplers has greatly simplified the anastomosis procedure and also decreased the time required to perform an anastomosis.

In general, a conventional circular stapler typically consists of an elongated shaft that has a proximal actuating mechanism and a distal stapling mechanism mounted to the shaft. The distal stapling mechanism commonly consists of a fixed stapling cartridge that contains a plurality of staples configured in a concentric circular array. A round cutting knife is concentrically mounted in the cartridge interior to the staples for axial travel therein. Extending axially from the center of the cartridge is a movable trocar shaft that is adapted to have a staple anvil removably coupled thereto. The anvil is configured to form the ends of the staples as they are driven into it. The distance between a distal face of the staple cartridge and the staple anvil is controlled by an adjustment mechanism mounted to the proximal end of the stapler shaft for controlling the axial movement of the trocar. Tissue clamped between the staple cartridge and the staple anvil is simultaneously stapled and cut when the actuating mechanism is activated by the surgeon.

When performing an anastomosis using a circular stapler, the intestine is typically stapled using a conventional surgical stapler with double rows of staples being emplaced on either side of the diseased portion of intestine to be removed. The target section is simultaneously cut as the adjoining end is stapled. After removing the diseased portion, the surgeon typically inserts the anvil into the proximal end of the lumen, proximal of the staple line. This is done by inserting the anvil head into an entry port cut into the proximal lumen by the surgeon. On occasion, the anvil can be placed transanally, by placing the anvil head on the distal end of the stapler and inserting the instrument through the rectum. The surgeon then ties the proximal end of the intestine to the anvil shaft using a suture or other conventional tying device. Next, the surgeon cuts excess tissue adjacent to the tie and the surgeon attaches the anvil to the trocar shaft of the stapler. The surgeon then closes the gap between the anvil and cartridge, thereby clamping the proximal and distal ends of the intestine in the gap. The surgeon next actuates the stapler causing several rows of staples to be driven through both ends of the intestine and formed, thereby joining the ends and forming a tubular pathway. Simultaneously, as the staples are driven and formed, the concentric circular knife blade is driven through the intestinal tissue ends, cutting the ends adjacent to the inner row of staples. The surgeon then withdraws the stapler from the intestine and the anastomosis is complete.

During the aforementioned stapling process, it is often difficult for the surgeon to effectively view the area of the colon being cut and stapled. To assist the surgeon, separate endoscopes equipped with cameras and lighting systems are employed. However, due to the limited amount of space available to maneuver and position such instrument within the colon, such instruments may not supply a desired amount of illumination to the area. Thus, there is a need for a circular stapler that is equipped with a source of illumination.

During the above-described surgical procedures, the need exists to provide feedback to the surgeon that the anvil is properly attached to the device prior to closing and firing. For example, in a lower anterior resection, it is often difficult for the surgeon to know if they have successfully attached the anvil to the trocar. Adverse outcomes may occur if the stapler is fired prior to securing the anvil to the device. Thus another need exists for a device for indicating when the anvil has been properly attached to the device.

Also during the above-described surgical procedures, it is often difficult for the surgeon to know when the anvil has been moved to the desired closed position wherein it is ready to be fired. Thus, there is a need for a feedback arrangement for a circular stapler that provides the surgeon with an indication that the anvil has been moved to the desired firing position.

<CIT> describes a surgical fastening instrument which employs an adjustable closure mechanism and a visual indicator. The fastening instrument is provided with a stationary hand grip or hand rest and an actuating handle. An elongated body portion is provided that terminates in a distal jaw mechanism including an anvil jaw and a cartridge jaw. A fastener cartridge is positioned within the cartridge jaw for driving staples or fasteners through tissue against an anvil surface positioned on the anvil jaw. At the handle end of the instrument is a push button for operating an advancement mechanism. The push button and an advancing mechanism extend outwardly from the proximal end of the instrument. A releasable retaining mechanism is coupled to a slider mechanism so that as the slider mechanism is urged forward into a housing, the retaining mechanism slides forward along a stationary rod. An electrical circuit within the surgical instrument is positioned on the slider mechanism. The visual indicator is in the form of an LED and is disposed in the housing. The electrical circuit includes a wire that electrically connects the indicator to a battery, a wire that connects the battery to a contact, and a wire that connects the indicator to another contact. Illumination of the indicator is accomplished by closing the circuit which is achieved by bringing these two contacts into abutment. After tissue which is to be surgically repaired is positioned between the cartridge jaw and the anvil jaw, the push button is pushed and moves the slider mechanism into the housing. Distal movement of the slider mechanism carries one contact distally toward the other contact. Once the device is ready to be fired, the contacts and are in abutment as the slider mechanism has travelled distally, thereby completing the circuit, and allowing electrical current to flow from the voltage source to the indicator. The indicator therefore becomes lit to inform the user that the cartridge jaw is spaced a desired distance from the anvil jaw.

<CIT> describes a surgical stapling device comprising a handle portion, and elongated body portion and a head portion. The elongated body portion extends distally from the handle portion. The head portion includes an anvil assembly and a shell assembly housing a plurality of staples, the anvil assembly being movable in relation to the shell assembly between spaced and approximated positions. An approximation mechanism includes an anvil retainer to releasably engage the anvil assembly, and a retractable trocar assembly includes a trocar slidably supported by the anvil retainer, the trocar being movable between a retracted position located within the anvil retainer to an advanced position extending from the anvil retainer. An indicator is supported on the handle portion, the indicator providing a visual indication identifying whether the anvil assembly has been attached to the anvil retainer. The anvil assembly includes a center rod configured to engage the retractable trocar assembly during attachment of the anvil assembly to the anvil retainer to move the trocar from the advanced position to the retracted position. The trocar is operably connected to the indicator assembly, such that movement of the trocar between the advanced and retracted positions effects movement of the indicator.

<CIT> and <CIT> describe surgical staplers include a non-contact sensor such as a Hall effect sensor to detect the proximity of various parts of the stapler. For example, once a trigger switch actuates a motor, an axial drive traverses distally to actuate the stapler cartridge. A magnetic member moves with the axial drive towards or away from the non-contact sensor. The detected distance from the magnetic member and the sensor is used to modulate operation of the motor.

<CIT> describes a surgical stapling instrument that includes a plurality of contact sensors, placed along the length of the tissue contacting surfaces of a shell assembly and an anvil assembly. The contact sensors are connected to a processor and provide an indication of when tissue is located between the shell assembly and the anvil assembly. In operation, once initial contact is made between the contact sensors, an inductive sensor, such as a tissue linear variable differential transformer, can be used to determine the gap between the shell assembly and the anvil assembly. BRIEF SUMMARY.

In one general aspect of the present invention, there is provided a surgical stapling instrument for applying one or more surgical staples to tissue, according to claim <NUM>. The instrument comprises a handle assembly and a shaft assembly that is coupled to the handle assembly and movably supports a trocar assembly therein. A stapling head assembly is operably coupled to the shaft assembly. The stapling head assembly comprises a staple cartridge for supporting one or more surgical staples and a staple driver for engaging and driving the staples from the staple cartridge. A knife is also movably supported in the stapling head assembly. The surgical stapling instrument further includes a drive system for applying drive motions to the staple driver assembly and the knife. An anvil is removably attachable to a distal end of the trocar assembly. An illumination device is attached to the anvil. The illumination device is electrically connected to a source of electrical current. At least one sensor is provided on one of the anvil and the trocar assembly and is electrically coupled to the source of electrical current and the illumination device such that when the anvil is attached to the distal end portion of the trocar assembly, electrical current flows from the source of electrical current to the illumination device.

In accordance with another general form of the present invention, there is provided a surgical stapling instrument for applying one or more surgical staples to tissue, according to claim <NUM>. The instrument comprises a handle assembly and a shaft assembly that is coupled to the handle assembly. A stapling head assembly is operably coupled to the shaft assembly. The stapling head assembly comprises a staple cartridge for supporting one or more surgical staples, and a staple driver for engaging and driving the staples from the staple cartridge. A knife is movably supported in the stapling head assembly. A drive system is provided for applying drive motions to the staple driver and the knife. The instrument further includes a source of electrical current. An indicator is also provided on the instrument. The indicator communicates with the source of electrical current. A trocar assembly is movably supported by the shaft assembly and configured to detachably support an anvil thereon. The trocar assembly has a first contact region and a second contact region that communicate with the source of electrical current and the indicator. the second contact region is electrically insulated from the first contact region such that when the anvil is attached to the distal end of the trocar assembly, the anvil electrically connects the first and second contact regions to permit the electrical current to flow to the indicator.

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and, together with the general description of the invention given above, and the detailed description of the embodiments given below, serve to explain the principles of the present invention.

Certain exemplary embodiments will now be described to provide an overall understanding of the principles of the structure, function, manufacture, and use of the devices disclosed herein. One or more examples of these embodiments are illustrated in the accompanying drawings. Those of ordinary skill in the art will understand that the devices specifically described herein and illustrated in the accompanying drawings are non-limiting exemplary embodiments and that the scope of the present invention is defined solely by the claims. The features illustrated or described in connection with one exemplary embodiment may be combined with the features of other embodiments.

Turning to the Drawings, wherein like numerals denote like components, there is shown a circular stapler <NUM> that includes a unique and novel system for providing feedback to the surgeon to indicate when the detachable anvil <NUM> thereof has been properly attached to the stapler <NUM>. A variety of different circular staplers are known in the art. <FIG> illustrate an exemplary circular stapler arrangement that may employ the benefits of various aspects of the present invention. It is conceivable, however, that the various embodiments of the present invention may be successfully employed with other stapler constructions.

It will be appreciated that the terms "proximal" and "distal" are used herein with reference to a clinician manipulating the handle portion of the surgical instrument. The term "proximal" referring to the portion closest to the clinician and the term "distal" referring to the portion located away from the clinician. It will be further appreciated that, for convenience and clarity, spatial terms such as "vertical", "horizontal", "up" and "down" may be used herein with respect to the drawings. However, surgical instruments are used in many orientations and positions, and these terms are not intended to be limiting and/or absolute.

As can be seen in <FIG>, there is disclosed a circular stapler <NUM> that includes a stapling head assembly <NUM>, an anvil <NUM>, an adjustment knob <NUM>, and a trigger <NUM>. The stapling head assembly <NUM> is coupled to a handle assembly <NUM> by a shaft assembly <NUM>. The trigger <NUM> is pivotally supported by the handle assembly <NUM> and is configured to operate the stapler <NUM> when a safety mechanism <NUM> is released. When the trigger <NUM> is activated, a drive system operates within the shaft assembly <NUM> so that staples <NUM> (<FIG>) are expelled from the stapling head assembly <NUM> into forming contact with the anvil <NUM>. Simultaneously, a knife <NUM>, that is operably supported within the head <NUM>, acts to cut tissue held within the circumference of the stapled tissue. The stapler <NUM> is then pulled through the tissue leaving stapled tissue in its place.

<FIG> illustrates one form of anvil <NUM> and stapling head assembly <NUM> that may be employed in connection with various embodiments of the subject invention. As can be seen in that Figure, the anvil <NUM> may have a circular body portion <NUM> that has an anvil shaft <NUM> for attaching a trocar <NUM> (<FIG>) thereto. The anvil body <NUM> has a staple forming undersurface <NUM> thereon. In various embodiments, a shroud <NUM> is attached to the distal end of the anvil body <NUM>. The anvil <NUM> may be further provided with a pair of trocar retaining clips or leaf-type springs <NUM> that serve to releasably retain the trocar <NUM> in retaining engagement with the anvil shaft <NUM> as will be discussed in further detail below.

As can also be seen in <FIG>, the stapling head assembly <NUM> may comprise a casing member <NUM> that supports a cartridge supporting assembly in the form of a staple driver <NUM> that is adapted to interface with a circular staple cartridge <NUM> and drive staples <NUM> supported therein into forming contact with the staple forming undersurface <NUM> of anvil <NUM>. A circular knife <NUM> is centrally disposed within the staple driver <NUM> and has a distal cutting edge <NUM> formed thereon. The proximal end <NUM> of the casing member <NUM> may be coupled to an outer tubular shroud <NUM> of the shaft assembly <NUM> by a distal ferrule member <NUM>.

<FIG> illustrates a shaft assembly <NUM> that operably supports the trocar <NUM> and compression shaft <NUM> for axial movement therein. The compression shaft 54may be axially and movably supported within the outer tubular shroud <NUM> and include a distal compression shaft portion <NUM>. As can also be seen in <FIG>, the distal compression shaft portion <NUM> is coupled to the staple driver <NUM>. Thus, axial movement of the compression shaft portion <NUM> within the outer tubular shroud <NUM> causes the staple driver <NUM> to move axially within the casing member <NUM>. Actuation of the firing trigger <NUM> (<FIG>) will cause the compression shaft <NUM> and the distal compression shaft portion <NUM> to move in the distal direction (arrow "DD") thereby driving the staple driver <NUM> distally to fire the staples <NUM> into forming contact with the staple forming undersurface <NUM> of the anvil <NUM>. As the staple driver <NUM> is driven distally, it also drives the cutting edge <NUM> of the knife <NUM> through the tissue held within the circumference of the stapled tissue into a knife board <NUM> mounted in the anvil <NUM>.

The trocar <NUM> may include a trocar tip <NUM> that has attached thereto a top tension band <NUM> and a bottom tension band <NUM>. The trocar tip <NUM> may be coupled to the top tension band <NUM> and bottom tension band <NUM> by fasteners <NUM> (e.g., screws, studs, posts, etc.). A spacer band <NUM> is received within the tubular shroud <NUM> and serves to slidably support the upper and lower tension bands <NUM>, <NUM> within the shroud <NUM>. The proximal ends of the top tension band <NUM> and bottom tension band <NUM> may be attached to a distal end of an adjustment shaft <NUM>. As illustrated in <FIG>, the tip <NUM> of the trocar <NUM> may be inserted into the anvil shaft <NUM> of the anvil <NUM> and retained in engagement by the trocar retaining clips <NUM>.

In various embodiments, the adjustment shaft <NUM> may be axially movably supported within a handle assembly <NUM> of the type and construction disclosed in U. Patent Publication No. US-<NUM>-<NUM>-A1 to Todd Philip Omaits, et al. , filed September <NUM>, <NUM>. However, other handle and firing system arrangements may be employed.

Various embodiments of the present invention include a unique and novel anvil feedback system generally designated as <NUM> for, among other things, providing the surgeon with an indication that the anvil <NUM> has been properly coupled to the trocar <NUM>. One embodiment of the tissue feedback system <NUM> may include at least one indicator <NUM> that may be mounted to the distal end of the shroud <NUM>. In various embodiments, for example, the indicator <NUM> may comprise at least one illumination device such as, for example, at least one light emitting diode (LED) or other lighting device. As can be seen in <FIG> and <FIG>, the indicator <NUM> may be connected to a Direct Current ("DC") power source <NUM> that may comprise a battery or number of batteries <NUM> or other suitable DC power source by a wire or conductor <NUM>. The battery <NUM> may also be supported within the shroud <NUM> such that it may be easily installed and replaced. The indicator <NUM> may also be connected to a sensor <NUM> that is mounted in the shaft <NUM> of the anvil <NUM> by a first wire or conductor <NUM>. The sensor <NUM> may also be connected to the power source <NUM> by another conductor or wire <NUM>.

In various embodiments, sensor <NUM> may comprise a switch <NUM> that is normally open in its unactuated position such that no current flows to the illumination device light <NUM> until the switch <NUM> is closed. The switch <NUM> is so positioned within or on the shaft <NUM> of the anvil <NUM> such that when the trocar tip <NUM> is properly affixed to the shaft <NUM> (i.e., seated within the shaft <NUM> as shown in <FIG> and retained in such position by retaining clips <NUM>), the switch <NUM> is closed which permits the current to flow from the battery <NUM> to the indicator <NUM>. Switch <NUM> may comprise a variety of different switch arrangements. For example, switch <NUM> may comprise a mechanically actuated switch (i.e., a switch that is mechanically closed by virtue of contact with the trocar tip <NUM>). However, the switch <NUM> could also be a magnetic switch, etc. that is actuated when the trocar tip <NUM> has been seated in its properly coupled position within the shaft <NUM> of the anvil <NUM>.

Those of ordinary skill in the art will appreciate that the anvil feedback system <NUM> provides an indication to the surgeon that the anvil <NUM> has been properly coupled to the trocar <NUM>. While only one indicator <NUM> has been illustrated as being mounted to the shroud <NUM>, it will be understood that more than one indicator could be employed and supported in other orientations on the anvil body <NUM>. Still in other embodiments, one indicator <NUM> in the form of an illumination device may be supported by the anvil to illuminate the surgical site as well as provide an indication that the anvil has been properly attached and another indicator (not shown) may be supported on the handle assembly or shaft to provide the surgeon with another indication that the anvil has been properly affixed to the trocar <NUM> without having to specifically look at the anvil or surgical site. Such indicators mounted to the handle assembly could comprise, for example, an illumination device, a sound generating device, a vibration generating device, etc..

The use of the circular stapler <NUM> will now be described with reference to <FIG>. When performing an anastomosis using a circular stapler <NUM>, the intestine <NUM> may be stapled using a conventional surgical stapler with multiple rows of staples being emplaced on either side of a target section (i.e., specimen) of intestine <NUM>. <FIG> illustrates the liner staple lines <NUM>, <NUM>. The target section is typically simultaneously cut as the section is stapled. The target section has already been excised in <FIG>. After removing the target specimen, the surgeon inserts the anvil <NUM> into the proximal portion <NUM> of the intestine <NUM>, proximal of the staple line <NUM>. This is done by inserting the anvil head <NUM> into an entry port cut into the proximal intestine portion <NUM> or the anvil <NUM> can be placed transanally, by placing the anvil <NUM> on the distal end of the stapler <NUM> and inserting the instrument through the rectum. Next, the surgeon attaches the anvil <NUM> to the trocar tip <NUM> of the stapler <NUM>. Once the trocar tip <NUM> has been inserted into the anvil shaft <NUM> to a position wherein the proximal end <NUM> of the anvil shaft <NUM> is seated on a shoulder portion <NUM> of the trocar <NUM> and the retaining clips <NUM> retainingly engage the trocar tip <NUM>, the switch <NUM> is closed to permit current to flow from the battery <NUM> to the indicator <NUM>. The surgeon may observe that the indicator <NUM> is illuminated by employing a video camera (not shown) that is supported through an endoscope (not shown) to enable the surgeon to view the surgical site (or if another indicator is provided on the handle assembly or shaft assembly, the surgeon may receive an indication from that device that the anvil has been properly attached to the trocar <NUM>). Those of ordinary skill in the art will appreciate that when the indicator <NUM> comprises at least one illumination device attached to the anvil <NUM>, the indicator <NUM> provides an indication that the anvil <NUM> has been properly attached to the trocar <NUM> as well as illuminates the surgical site.

Once the anvil <NUM> has been properly coupled to the trocar tip <NUM>, the anvil <NUM> is inserted into the distal portion <NUM> of the intestine <NUM>. The surgeon may then tie the distal end <NUM> of the proximal section <NUM> of the intestine <NUM> to the anvil shaft <NUM> using a suture <NUM> or other conventional tying device and also tie the proximal end <NUM> of the distal intestine portion <NUM> around the anvil shaft using another suture <NUM>. The surgeon then begins to rotate the closure knob assembly <NUM> (<FIG>) to draw the anvil <NUM> toward the cartridge <NUM> supported in the staple driver <NUM> to close the gap between the anvil <NUM> and cartridge <NUM> and thereby engage the proximal end <NUM> of the distal intestine portion <NUM> with the distal end <NUM> of the proximal intestine portion <NUM> in the gap "G" therebetween. The surgeon continues to rotate the closure knob assembly <NUM> until the desired gap G is attained. When in that "firing" position, the surgeon may then pivot the safety yoke <NUM> to the off position and fire the stapler <NUM> by depressing the firing trigger <NUM>. Depressing the trigger <NUM> causes the compression shaft <NUM> to drive the staple driver <NUM> distally to drive the staples <NUM> to be driven through both ends <NUM>, <NUM> of the intestine <NUM>, thereby joining the portions <NUM> and <NUM> and forming a tubular pathway. Simultaneously, as the staples <NUM> are driven and formed, the knife <NUM> is driven through the intestinal tissue ends <NUM> and <NUM>, cutting the ends adjacent to the inner row of staples <NUM>.

<FIG> illustrate another circular stapler <NUM>' that may employ some unique and novel features of the present invention. Those components of stapler <NUM>' that are identical to the above-described components are labeled with like numbers. In one embodiment, for example, the anvil <NUM> lacks the indicator <NUM> of the prior embodiments. In this embodiment, however, the trocar <NUM> is formed with two or more contact regions <NUM> and <NUM> that are electrically isolated from each other by an electrical insulator <NUM>. More specifically and with reference to <FIG>, the trocar <NUM> includes a body portion <NUM> that is coupled to the top tension band <NUM> and bottom tension band <NUM> by fasteners <NUM> in the manner described above. The body portion <NUM> has a distal end portion <NUM> that terminates in tip <NUM> and which has the first contact region or shoulder <NUM> formed thereon. The body <NUM> of the trocar <NUM> is fabricated from an electrically conductive material such as, for example, stainless steel, titanium, aluminum, etc. Received on distal portion <NUM> of the trocar <NUM> is an electrical insulator sleeve <NUM> that may be fabricated from, for example, a thermoplastic material such as Vectra®, high density polyethylene (HDPE), Ultem®, etc. Mounted on the electrical insulator <NUM> is a contact bushing <NUM>. Contact bushing <NUM> is fabricated from electrically conductive material such as, for example, stainless steel, titanium, aluminum, etc. The contact bushing <NUM> has a distal shoulder <NUM> formed thereon which defines a second contact surface <NUM> for engagement with the proximal end portion <NUM> of the hollow anvil shaft <NUM>.

A first conductor or wire <NUM> is connected to the contact bushing <NUM>. In various embodiments, the contact bushing <NUM> may have a slot or groove <NUM> sized to receive an end of the conductor <NUM> which may be soldered, and/or glued or otherwise electrically connected thereto. A second conductor or wire <NUM> maybe attached to body portion <NUM> by one or both of the fasteners <NUM> that also serve to couple the top and bottom tension bands <NUM>, <NUM> thereto. However, the second conductor <NUM> may be electrically coupled to the body portion <NUM> of the trocar <NUM> by other suitable methods.

<FIG> depicts one form of an indicator circuit <NUM> that may be employed. As can be seen in that Figure, a Direct Current ("DC") power source <NUM>, that may comprise a battery or number of batteries <NUM> or other suitable DC power source, is connected to the contact bushing <NUM> which is mounted on the electrical insulator <NUM> that is mounted on the trocar body <NUM> as illustrated in <FIG>. The second conductor <NUM> is connected to the electrically conductive trocar body <NUM> and an indicator <NUM> that is mounted on the handle assembly <NUM>. The indicator <NUM> is, in turn, connected to the power source <NUM> by a conductor <NUM>. The indicator <NUM> may comprise at least one light emitting diode ("LED") or other suitable light source. Thus, when the shaft <NUM> of the anvil <NUM> is properly received on the distal portion <NUM> such that the proximal end <NUM> of the shaft <NUM> is seated on the second contact region <NUM>, the shaft <NUM> is also in contact with the first contact region <NUM> which completes the circuit <NUM> and cause the indicator <NUM> to be energized. Such arrangement provides the surgeon with a positive indication that the anvil <NUM> has been properly attached to the trocar <NUM>. <FIG> illustrates an alternative indicator circuit <NUM>' which employs a microprocessor <NUM> that may be housed within the handle assembly <NUM> to control the indicator <NUM> when the anvil <NUM> has been attached to the trocar <NUM> to complete the circuit.

As was discussed above, once the anvil <NUM> has been properly coupled to the trocar <NUM>, the anvil <NUM> is inserted into the distal portion <NUM> of the intestine <NUM>. The surgeon may then tie the distal end <NUM> of the proximal section <NUM> of the intestine <NUM> to the anvil shaft <NUM> using a suture <NUM> or other conventional tying device and also tie the proximal end <NUM> of the distal intestine portion <NUM> around the anvil shaft using another suture <NUM>. The surgeon then begins to rotate the closure knob assembly <NUM> (<FIG>) to draw the anvil <NUM> toward the cartridge <NUM> supported in the staple driver <NUM> to close the gap between the anvil <NUM> and cartridge <NUM> and thereby engage the proximal end <NUM> of the distal intestine portion <NUM> with the distal end <NUM> of the proximal intestine portion <NUM> in the gap "G" therebetween. The surgeon continues to rotate the closure knob assembly <NUM> until the desired gap G is attained. To assist the surgeon in determining when the anvil <NUM> has been moved to the desired firing position relative to the staple cartridge <NUM>, various embodiments may also be provided with a closure circuit <NUM>.

More particularly and with reference to <FIG>, the closure circuit <NUM> may include the power source <NUM>, the first contact region <NUM> on the body portion <NUM> of the trocar <NUM> and a second contact region <NUM> formed on the contact bushing <NUM> as was described above as well as a string potentiometer <NUM> or other distance sensor to control a variable resistor. The string potentiometer <NUM> is configured and mounted within the shaft <NUM> or handle assembly <NUM> and coupled to the trocar <NUM> or adjustment shaft <NUM> to detect the axial distance that the trocar <NUM> moves in the proximal "PD" direction from a starting position wherein the anvil <NUM> has been properly coupled thereto. When employing this feature, the trocar <NUM> may be positioned (by virtue of rotating the control knob <NUM>) in a starting position wherein the anvil <NUM> may be attached thereto in the manner described above. The string potentiometer <NUM> is set such that resistance is low when the anvil <NUM> has been properly coupled to the trocar <NUM> in the starting position. Thus, when the anvil <NUM> has been attached to the trocar <NUM>, resistance is low and the indicator <NUM> is energized to provide the surgeon with an indication that the anvil <NUM> has been properly attached. As the surgeon then rotates the adjustment knob <NUM> to draw the anvil <NUM> proximally toward the cartridge <NUM>, resistance in the string potentiometer <NUM> increases and reduces the amount of current flowing to the indicator <NUM> thereby dimming the indicator <NUM> until the anvil reaches a desired firing position (i.e., the desired gap "G" has been achieved). At that point, the resistance is increased to a level wherein little or no current flows to the indicator light <NUM> to cause it to go out. Thus, the surgeon can watch the indicator <NUM> during the closing process and when the light goes out, the surgeon knows that the anvil <NUM> has been positioned in the desired firing position.

While this embodiment employs a string potentiometer to adjust the resistance in the closure circuit <NUM> as the trocar <NUM> and anvil <NUM> are adjusted, other circuit arrangements may be employed. For example, a transistor based amplifier such as a Darlington pair that is controlled by the axial distance that the trocar <NUM> is moved may be employed. In still other embodiments, a circuit <NUM>' may be employed which includes a microprocessor <NUM> for controlling the illumination of the indicator <NUM> as the anvil <NUM> is axially advanced to a desired closed position.

While several embodiments of the invention have been described, it should be apparent, however, that various modifications, alterations and adaptations to those embodiments may occur to persons skilled in the art with the attainment of some or all of the advantages of the invention. For example, a single component may be replaced by multiple components, and multiple components may be replaced by a single component, to perform a given function or functions.

The devices disclosed herein can be designed to be disposed of after a single use, or they can be designed to be used multiple times. In either case, however, the device can be reconditioned for reuse after at least one use. Reconditioning can include an combination of the steps of disassembly of the device, followed by cleaning or replacement of particular pieces, and subsequent reassembly. In particular, the device can be disassembled, and any number of particular pieces or parts of the device can be selectively replaced or removed in any combination. Upon cleaning and/or replacement of particular parts, the device can be reassembled for subsequent use either at a reconditioning facility, or by a surgical team immediately prior to a surgical procedure. Those of ordinary skill in the art will appreciate that the reconditioning of a device can utilize a variety of different techniques for disassembly, cleaning/replacement, and reassembly.

Preferably, the invention described herein will be processed before surgery. First a new or used instrument is obtained and, if necessary, cleaned. The instrument can then be sterilized. In one sterilization technique, the instrument is placed in a closed and sealed container, such as a plastic or TYVEK® bag. The container and instrument are then placed in a field of radiation that can penetrate the container, such as gamma radiation, x-rays, or higher energy electrons. The radiation kills bacteria on the instrument and in the container. The sterilized instrument can then be stored in the sterile container. The sealed container keeps the instrument sterile until it is opened in the medical facility.

Claim 1:
A surgical stapling instrument (<NUM>) for applying one or more surgical staples (<NUM>) to tissue, comprising:
a handle assembly (<NUM>);
a shaft assembly (<NUM>) coupled to said handle assembly (<NUM>) and movably supporting a trocar assembly (<NUM>) therein;
a stapling head assembly (<NUM>) operably coupled to said shaft assembly(<NUM>), said stapling head assembly (<NUM>) comprising:
a staple cartridge (<NUM>) for supporting one or more surgical staples (<NUM>);
a staple driver (<NUM>) for engaging and driving the staples (<NUM>) from said staple cartridge (<NUM>); and
a knife (<NUM>) movably supported in said stapling head assembly (<NUM>);
a drive system (<NUM>, <NUM>, <NUM>) for applying drive motions to said staple driver (<NUM>) and said knife (<NUM>);
an anvil (<NUM>) removably attachable to a distal end of said trocar assembly (<NUM>);
an illumination device (<NUM>) attached to said anvil (<NUM>), said illumination device (<NUM>) electrically connected to a source of electrical current (<NUM>); and
at least one sensor (<NUM>) electrically coupled to said source of electrical current (<NUM>) and said illumination device (<NUM>);
characterized in that said at least one sensor (<NUM>) is on one of said anvil (<NUM>) and said trocar assembly (<NUM>) and is electrically coupled such that when said anvil (<NUM>) is attached to said distal end portion of said trocar assembly (<NUM>), electrical current flows from said source of electrical current (<NUM>) to said illumination device (<NUM>).