Abstract:
An apparatus for indicating the amount of tension applied to separate internal organ sections includes a housing, a shaft extending from the housing, and a fastener applier. The fastener applier is supported on the shaft. The fastener applier includes an anvil assembly and a cartridge assembly. The anvil assembly is positionable between first and second positions relative to the cartridge assembly. The anvil assembly and the cartridge assembly include a tissue detection device positioned to contact separate internal organ sections to generate a signal indicative of an amount of tension between the organ sections as the anvil assembly moves between the first and second positions. The tissue detection device is operably coupled to a gauge configured and dimensioned to generate an output based upon the signal. The output indicates the amount of tension between the organ sections.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 11/446,646, filed on Jun. 5, 2006, which claims priority to, and the benefit of, U.S. Provisional Patent Application Ser. No. 60/687,214, filed Jun. 3, 2005, the entire disclosures of which are incorporated by reference herein. 
    
    
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to a method and/or apparatus for measuring the tension in body tissue. More particularly, the present disclosure relates to a method and/or apparatus for measuring the tension in body tissue at a site of a surgical anastomosis. 
     2. Background of Related Art 
     Anastomosis is the surgical joining of separate hollow organ sections. Typically, an anastomosis procedure follows a surgical procedure in which a diseased or defective section of hollow tissue is removed and the remaining end sections are drawn together and joined. Depending on the desired anastomosis procedure, the end sections may be joined by either circular, end-to-end, or side-to-side organ reconstruction methods. 
     In a known circular anastomosis procedure, two ends of organ sections are drawn together and joined by means of a stapling device which drives a circular array of staples through the end of each organ section and simultaneously cores any tissue interior of the driven circular array of staples to free a tubular passage. Examples of devices for performing circular anastomosis of hollow organs are described in U.S. Pat. Nos. 6,053,390; 5,588,579; 5,119,983; 5,005,749; 4,646,745; 4,576,167; and 4,473,077, each of which is incorporated herein in its entirety by reference. Typically, these devices include an elongated shaft having a handle portion at a proximal end thereof to effect actuation of the device and a staple holding component disposed at a distal end thereof. An anvil assembly including an anvil shaft with attached anvil head is mounted to the distal end of the device such that the anvil head is movable towards the staple holding component. The two ends of the organ sections are drawn together and clamped between the anvil head and the staple holding component of the device by securing one end of the organ section to the anvil assembly, securing the other end of the organ section about the staple holding component, and moving the anvil head towards the staple holding component. The clamped tissue is stapled by driving one or more staples from the staple holding component so that the ends of the staples pass through the organ sections and are deformed by the anvil head. An annular knife is concurrently advanced to core tissue within the hollow organ to free a tubular passage within the organ. Typically, this procedure is conducted endoscopically or laparoscopically using endoscopic instruments. 
     Although the circular anastomosis procedure described above has provided substantial improvements to surgical procedures requiring anastomosis, additional improvements are desired. For example, when the two ends of the organ sections to be anastomosed are drawn together, tension is generated in the organ sections. Because of the type of surgery, it can be difficult for a surgeon to determine how much tension is being or has been applied to the organ sections at the anastomotic site. Excessive tension on the organ sections at the anastomotic site may result in complications, e.g., strictures, postoperative leaks, necrosis, etc. 
     Accordingly, it would be desirable to provide a surgical apparatus and/or method for measuring the tissue tension at an anastomotic site and providing a surgeon with immediate data indicating the magnitude of the tension. It would also be desirable to provide an apparatus which is suitable for use with a circular anastomosis device and could measure the initial and residual tension at an anastomotic site during a surgical procedure. 
     SUMMARY 
     The present disclosure is directed to an apparatus for indicating the amount of tension applied to separate internal organ sections. The apparatus includes a housing, a shaft extending from the housing, and a fastener applier. The fastener applier is supported on the shaft. The fastener applier includes an anvil assembly and a cartridge assembly. The anvil assembly is positionable between first and second positions relative to the cartridge assembly. The anvil assembly moves a first organ section towards a second organ section as the anvil assembly moves between the first and second positions such that an amount of tension is generated between the first and second organ sections. In the first position, the anvil assembly is spaced apart from the cartridge assembly, and in the second position, the anvil assembly is in close cooperative alignment with cartridge assembly. 
     The anvil assembly and the cartridge assembly include a tissue detection device positioned to contact separate internal organ sections to generate a signal indicative of an amount of tension between the organ sections as the anvil assembly moves between the first and second positions. The tissue detection device is operably coupled to a gauge configured and dimensioned to generate an output based upon the signal. The output indicates the amount of tension between the organ sections. 
     In embodiments, the tension detection device includes a pair of contacts. One or more contacts are positioned to extend through one or more openings formed in one or both of the anvil assembly and the cartridge assembly. One or more contacts may be movable between extended and retracted positions. One or more contacts may extend or retract from the one or more openings in response to movement of the anvil assembly between the first and second positions. The housing may include a switch that extends and retracts the one or more contacts upon the actuation of the switch. One or more of the contacts may be connected to the gauge by one or more wires. 
     In embodiments, the gauge may be supported within the fastener applier. The gauge may be a strain gauge. The gauge may be operably coupled to an indicator supported on the housing that displays the output. In embodiments the indicator displays the output in real time. 
     According to one aspect, the present disclosure is directed to a method for detecting an amount of tension applied to organ sections and includes the step of providing an apparatus including a housing, a shaft extending from the housing, and a fastener applier. The fastener applier is supported on the shaft and includes an anvil assembly and a cartridge assembly having a tissue detection device. The tissue detection device is operably coupled to a gauge. The method includes the steps of positioning the anvil assembly between first and second positions relative to the cartridge assembly such that a first organ section moves towards a second organ section; applying tension to the organ sections; and generating an output that indicates an amount of tension between the organ sections. The method may include the steps of causing the tissue tension device to generate a signal indicative of the amount of tension between the organ sections and causing the gauge to generate the output based upon the signal. One step may include causing an indicator that is operably coupled to the gauge to display the output. In one embodiment, the tissue detection device includes a pair of contacts such that the method involves moving one or more of the contacts in response to movement of the anvil assembly between the first and second positions. One step may include moving one or more of the contacts between extended and retracted positions relative to one or both of the anvil assembly and the cartridge assembly. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the presently disclosed apparatus are described herein with reference to the drawings, wherein: 
         FIG. 1  is a front perspective view of an embodiment of the presently disclosed apparatus; 
         FIG. 2  is a front perspective view of an alternate embodiment of the presently disclosed apparatus; 
         FIG. 3  is a side view of another embodiment of the presently disclosed apparatus located at an anastomotic site between two organ sections; 
         FIG. 4  is a side view of a further embodiment of the presently disclosed apparatus located at an anastomotic site between two organ sections with no tension applied to the organ sections; and 
         FIG. 4A  is a side view of the apparatus of  FIG. 4  with tension applied to the organ sections. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Embodiments of the presently disclosed method and apparatus for measuring tissue tension at an anastomotic site will now be described in detail with reference to the drawings wherein like numerals designate identical or corresponding elements in each of the several views. As is common in the surgical apparatus art, the term proximal will refer to a location on the device closer to the operator of the device, e.g., surgeon, while the term distal will refer to a location on the device further away from the operator of the device. 
       FIG. 1  illustrates one embodiment of the presently disclosed apparatus for measuring tissue tension at an anastomotic site shown generally as  10 . Apparatus  10  is supported on a circular anastomosis fastener applier shown generally as  20 . Apparatus  10  includes a pair of contacts or leads  12  and  14  which are positioned at a distal end of circular anastomosis fastener applier  10 . Contact  12  includes a first end positioned to extend through an opening  16  formed in an anvil assembly  22  of fastener applier  20 . A second end of contact  12  communicates with a tension gauge (not shown), e.g., strain gauge, supported within housing  24  of fastener applier  10 . Contact  14  includes a first end positioned to extend through an opening  19  defined in a staple holding component or staple cartridge  26  of fastener applier  20 . A second end of contact  14  communicates with the tension gauge in housing  24  (not shown). Contacts  12  and  14  are positioned to contact each organ section adjacent the anastomotic site to supply a signal indicative of the magnitude of tissue tension to the tension gauge. The tension gauge translates the signal sent by contacts  12  and  14  into data identifying the magnitude of tension in the organ sections. Contacts  12  and  14  can be connected to the tension gauge by wires or the like. In one embodiment, a tension indicator  30  is supported on housing  24 . Tension indicator  30  communicates with the tension gauge to display in real time the tension in the organ sections. It is envisioned that fastener applier  20  may include a part which is connectable to a strain gauge and indicator which are located externally of housing  24 . 
     During an anastomotic procedure, anvil assembly  22  is repositioned towards staple cartridge  26  and moves a first organ section towards a second organ section, thereby applying an amount of tension to the organ sections. Anvil assembly  22  is repositionable, in relation to staple cartridge  26 , throughout a plurality of positions including a first position that is spaced apart from staple cartridge  26  and a second position that is in close cooperative alignment with the staple cartridge  26 . 
     In one embodiment, contacts  12  and  14  are retractable into and out of openings  16  and  19 , wherein contacts  12 ,  14  are repositionable between an extended position and a retracted position. In one embodiment, contacts  12  and  14  are extended from openings  16  and  19  in response to approximation of the anvil assembly  22  and staple holding component  24 . Alternatively, a manual switch may be provided to extend the contacts. 
       FIG. 2  illustrates an alternate embodiment of the presently disclosed apparatus for measuring tissue tension at an anastomotic site shown generally as  100 . Apparatus  100  is similar to apparatus  10  in that apparatus  100  includes a first contact  112  mounted on an anvil assembly  122  of fastener applier  120  and a second contact  114  mounted on a staple holding component or staple cartridge  124  of fastener applier  120 . However, contacts  112  and  114  are flat contacts which are mounted on an outer rim of both anvil assembly  122  and staple holding component  124  at a position to contact organ sections at a location adjacent the anastomotic site. Each contact  112  and  114  communicates with a tension gauge (not shown) supported within fastener applier  120  which communicates with a tension indicator  130  as discussed above with respect to apparatus  10 . As discussed above, it is envisioned that the tension gauge and indicator may be located externally of the fastener applier. 
     In a further embodiment, tension indicators  30 ,  130  may include an audible and/or visual alarm indicator (i.e. red light, buzzer, horn, bell, etc.) that informs the operator that a predetermined amount of tension is being applied to the organ sections. The setting for the alarm indicator is operator adjustable and the procedure to be performed is one of several criteria that is considered when establishing the predetermined amount of tension for the alarm setting. 
       FIG. 3  illustrates another embodiment of the presently disclosed apparatus for measuring tissue tension shown generally as  200  which is separate from a fastener applier. Apparatus  200  can be applied across an anastomotic site  230  to produce a reference indication of the magnitude of the tension where the organ sections are joined. Apparatus  200  includes an elongated member  210  formed of a material which bridges anastomotic site  230  and is, in one embodiment, initially slack. When excess tension exists in the anastomosed tissue, the material goes taut or releases from the tissue. In another embodiment, member  210  is secured to organ sections  232  and  234  using an adhesive or the like. Member  210  can be monitored endoscopically using an endoscope or other viewing equipment. Although apparatus  200  is illustrated as a strip of material, it is also contemplated that apparatus  200  may be a suture or any other material for maintaining the two sections of the anastomotic site in close approximation. It is further contemplated that apparatus  200  may be formed of a biocompatible and/or bioabsorbable material. 
     In another embodiment shown in  FIG. 4 , device  300  is formed of a body of material  310  which can be visualized via x-ray, MRI, CT scan, ultrasound or any other known device. Body of material  310  is positioned to bridge an anastomotic site  330 . In one embodiment, when excess tension is present in the tissue or organ sections  332  and  334 , body  310  undergoes a physical change to indicate excess tension at anastomotic site  330 , e.g., body  310  may be stretched (see  FIG. 4A ), such that the change in the width and/or length of body  310  is indicative of the change in tension applied to organ sections  332  and  334 . Further still, changes to the thickness of body  310  indicate the change in tension applied to organ sections  332  and  334 . It is envisioned that other changes may occur upon application of tension to body  310 , e.g., a color change may occur from a bioabsorbable marker, or a release from the organ sections may indicate a change in tension, etc. 
     The embodiments illustrated in  FIGS. 3-4A  are configured for measuring the tension applied to organ sections  232  and  234  or  332 ,  334  prior to approximation of the organ sections with a surgical stapling apparatus as well as during approximation and subsequent to the approximation. Further still, the disclosed embodiments are capable of measuring and indicating the amount of tension applied to the organ sections before, during, and after the firing of surgical staples from the surgical stapling apparatus. It is contemplated that devices  200 ,  300  may be formed from an elastic material as well as non-elastic materials. 
     In one embodiment, device  200  ( FIG. 3 ) is attached to organ sections  232 ,  234  prior to approximation of organ sections  232 ,  234 . This occurs after a section of the subject organ is removed between organ sections  232 ,  234 . Device  200  is attached using known endoscopic techniques through an access port (e.g. cannula) (not shown). Once attached, device  200  may be monitored through the access port using an endoscope (not shown). As organ sections  232 ,  234  are approximated using a circular anastomosis fastener (i.e. apparatus  10  as shown in  FIG. 1 ) tension is applied to organ sections  232 ,  234 . If the applied tension exceeds a predetermined amount, device  200  may detach at one or both attachment points or have a certain amount of slack between the attachment points. Specifically, once device  200  is attached to the spaced apart organ sections  232 ,  234 , movement of the organ sections towards one another (i.e. approximation) reduces the tension applied to device  200  and causes it to sag or go slack, whereupon, device  200  may detach from one or both of its attachment points. 
     In an alternate embodiment, device  200  is attached as described hereinabove to organ sections  232 ,  234  after approximation, but prior to joining organ sections  232 ,  234 . In this configuration, the practitioner observes device  200  as before. If the tension applied to organ sections  232 ,  234  exceeds a predetermined amount during the joining of the sections, device  200  may detach from one or both of the organ sections or go slack, as discussed hereinabove. 
     In a further embodiment, device  200  is attached as discussed hereinabove to organ sections  232 ,  234  after organ sections  232 ,  234  are anastomosed. In this configuration, device  200  is observed as before, wherein tension in the anastomosed organ sections  232 ,  234  will create tension in the attached device  200 . If the tension exceeds a predetermined amount, device  200  may stretch and/or deform, thereby indicating an excess tension condition. Alternatively, device  200  may include a sac of ink or dye that is released upon exceeding a predetermined amount of tension. 
     In another embodiment, a marker which reacts to strain or tension is applied to one or both of the organ sections to be joined. The marker can be an ink, polymer, or the like. When excess tension or any strain exists in the tissue sections, the marker reacts to the strain to provide an indication or reference of magnitude. The marker&#39;s reaction to the amount of tension applied to the organ sections may include changes in the marker&#39;s physical dimensions, a change in the marker&#39;s color, a reduction in an amount of slack in the marker, or separation of one end of the marker from an organ section. In addition, markers or devices  200 ,  300  may include a container (e.g. a pouch or a sac) that is embedded in marker  200 ,  300  such that an indicator (e.g. an ink or a dye) stored in the container is released when the tension applied to the organ sections exceeds a predetermined value. 
     In yet another embodiment, an electromechanical device may be operatively connected across the anastomotic site. The electromechanical device is configured to provide an output which provides an indication or measurement of tension at the site. 
     It will be understood that various modifications may be made to the embodiments disclosed herein. Thus, the above description should not be construed as limiting, but merely as illustrative of the disclosed apparatus and method. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.