CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. patent application Ser. No. 13/020,354, filed Feb. 3, 2011, which claims priority to, and the benefit of, U.S. Provisional Patent Application Ser. No. 61/309,606, filed Mar. 2, 2010. The entire contents of each of these disclosures are hereby incorporated by reference. 
     
    
     BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    The present disclosure relates to pressurized surgical instruments. More particularly, the present disclosure relates to pressurized surgical instruments incorporating pressurization mechanisms configured to internally balance or exceed pressures detected within an insufflated body cavity. 
         [0004]    2. Background of Related Art 
         [0005]    During certain surgical procedures, such as, for example, laparoscopic procedures, it is often necessary to separate a body wall of a patient from the underlying tissues in order to create a working space for the surgical instruments. This is typically accomplished by forming an incision through the body wall and inserting an access port or cannula through the incision. A source of expansion or insufflation fluids or gases is provided. The gases are forced through the cannula and into the body cavity. As the insufflation fluids enter the body cavity, the fluids force the body wall away from the underlying tissues to create the working space. This results in the working space having a higher internal pressure than that of the ambient pressure external to the body. 
         [0006]    Once the insufflated working space has been created, surgical instruments may be inserted through the cannula and into the insufflated body cavity to perform surgical procedures. These surgical instruments typically include a handle or body portion which remains external to the patient&#39;s body and an elongate tubular member having a working instrument or end effector which is inserted through the cannula and into the pressurized body cavity. Since the body cavity is at a higher pressure than that external to the body cavity, insufflation fluids tend to escape up through the elongate tubular member and exit through gaps in the body portion of the surgical instrument. This escape and flow of insufflation gases through the elongate tubular member creates a drawing or siphoning effect within the elongate tubular member which pulls bodily fluids and tissues through the end effectors and into the elongate tubular member. The introduction of bodily fluids and tissues into the end effector and the remainder of the surgical instrument contaminates and may clog the working components of the surgical instrument. This results in difficulty in operating the surgical instrument in addition to contaminants being passed through the surgical instrument. 
         [0007]    Therefore, it is desirable to provide a surgical instrument which prevents the escape of bodily fluids and tissues through the surgical instrument. It is further desirable to provide a surgical instrument which incorporates a pressurization mechanism to balance the pressures within the surgical instrument with the pressures within the body cavity in order to prevent escape of the insufflation fluids through the surgical instrument. It is still further desirable to provide a pressurized surgical instrument which can be utilized to augment the insufflation fluids provided by the cannula into the body cavity. 
       SUMMARY 
       [0008]    There is disclosed a pressurized surgical instrument having a body portion and an elongate tubular member extending from the body portion. A primary sensor is positioned within the surgical instrument for detecting a pressure in a working environment. The pressurized surgical instrument additionally includes a pressurization mechanism positioned within the body portion of the surgical instrument for balancing the pressure of the surgical instrument with the working environment. The pressurization mechanism includes a controller connected to the primary sensor and a pressure delivery system connected to the controller. The pressure delivery system provides positive pressure to the interior of the surgical instrument in response to a signal received from the controller and is in fluid communication with an interior of the surgical instrument. Specifically, the pressure delivery system is in fluid communication with an interior of the elongate tubular member 
         [0009]    The controller incorporates a second sensor for detecting a pressure within the surgical instrument. The controller compares the pressure in the working environment with the pressure within the surgical instrument. 
         [0010]    The pressure delivery system includes a tube and a distal end of the tube is connected to a collar in fluid communication with a proximal end of the elongate tubular member. The collar is in fluid communication with the proximal end of the elongate tubular member through a series of ports positioned about the collar. 
         [0011]    The primary sensor is positioned within the elongate tubular member. Specifically, the primary sensor is positioned adjacent a distal end of the elongate tubular member. The primary sensor is connected to the controller through a sensor cable. In a particular embodiment, the primary sensor and sensor cable are contained within a wall of the elongate tubular member. 
         [0012]    In one embodiment, the pressure delivery system includes a self-contained gas cartridge positioned within the body portion of the surgical instrument. The pressure delivery system includes a valve connected to the self-contained gas cartridge and to the controller such that the valve regulates gas released by the self-contained gas cartridge in response to a signal received from the controller. 
         [0013]    In an alternative embodiment, the pressure delivery system includes a pressurizing pump in fluid communication with the interior of the elongate tubular member and connected to the controller. A draw tube extends from the pressurized pump to a location and external of the body portion to draw low-pressure insufflation gases into the pump. 
         [0014]    In a further alternative embodiment, the pressure delivery system includes a valve and a connection tube extending from the valve to a connection fitting. The valve is connected to the controller. In this embodiment, the connection fitting is releasably attachable to an external source of insufflation fluids. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0015]    Various embodiments of the presently disclosed pressurized surgical instruments are disclosed herein with reference to the drawings, wherein: 
           [0016]      FIG. 1  is a side view, partially shown in section, of a prior art surgical instrument and prior art cannula inserted through a body cavity wall and into an insufflated or pressurized body cavity; 
           [0017]      FIG. 2  is a side view, partially shown in section, of a first embodiment of a pressurized surgical instrument inserted through the prior art cannula and into the pressurized body cavity; 
           [0018]      FIG. 3  is an enlarged area of detail view of  FIG. 2  illustrating a self-contained pressurization mechanism located within a handle or body portion of the pressurized surgical instrument; 
           [0019]      FIG. 4A  is an enlarged area of detail view of  FIG. 2  illustrating a primary sensor positioned adjacent a distal end of an elongate tubular member of the pressurized surgical instrument; 
           [0020]      FIG. 4B  is an enlarged area of detail view of  FIG. 2  illustrating a primary sensor positioned within a wall of the elongate tubular member of the pressurized surgical instrument; 
           [0021]      FIG. 5  is a view similar to  FIG. 2  illustrating actuation of the self-contained pressurization mechanism to equalize pressure within the elongate tubular member; 
           [0022]      FIG. 6  is a view similar to  FIG. 2  illustrating the actuation of the self-contained pressurization mechanism to create a pressure within the surgical instrument which is greater than the pressure within the pressurized body cavity; 
           [0023]      FIG. 7  is a side view, partially shown in section, of an alternative embodiment of a pressurized surgical instrument inserted through the prior art cannula and into the pressurized body cavity; 
           [0024]      FIG. 8  is an enlarged area of detail view of  FIG. 7  illustrating an alternative embodiment of a pressurization mechanism located within a handle or body portion of the pressurized surgical instrument; 
           [0025]      FIG. 9  is a view similar to  FIG. 7  illustrating the actuation of the pressurization mechanism to equalize pressure within an elongate tubular member of the pressurized surgical instrument; 
           [0026]      FIG. 10  is a view similar to  FIG. 7  illustrating the actuation of the pressurization mechanism to create a pressure within the surgical instrument which is greater than the pressure within the pressurized body cavity; 
           [0027]      FIG. 11  is a side view, partially shown in section, of a further alternative embodiment of a pressurized surgical instrument inserted through the prior art cannula and into a pressurized body cavity; 
           [0028]      FIG. 12  is an enlarged area of detail view of  FIG. 11  illustrating a further alternative embodiment of a pressurization mechanism located within a handle or body portion of the pressurized surgical instrument; 
           [0029]      FIG. 13  is a view similar to  FIG. 11  illustrating the actuation of the pressurization mechanism to equalize pressure within an elongate tubular member of the pressurized surgical instruments; and 
           [0030]      FIG. 14  is a view similar to  FIG. 11  illustrating the actuation of the pressurization mechanism to create a pressure within the pressurized surgical instrument which is greater than the pressure within the pressurized body cavity. 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0031]    Embodiments of the presently disclosed pressurized surgical instruments 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 art, the term ‘proximal” refers to that part or component closer to the user or operator, i.e. surgeon or physician, while the term “distal” refers to that part or component further away from the user. 
         [0032]    Referring initially to  FIG. 1 , there is illustrated a prior art surgical instrument  10  and a prior art cannula  12 . Prior art cannula  12  is illustrated inserted through an incision I formed through a body cavity wall BCW and extending into a body cavity BC. Prior art cannula  12  is provided to receive a portion of prior art surgical instrument  10  therethrough so as to perform surgical operations within body cavity BC. Prior art cannula  12  generally includes a body portion  14  and a cannula tube  16  extending distally from body portion  14 . Body portion  14  and cannula tube  16  form a throughbore  18  for receipt of portion of prior art surgical instrument  10 . Throughbore  18  extends from a proximal end  20  of body portion  14  to an open distal end  22  of cannula tube  16 . 
         [0033]    A pair of seals, such as, for example, seals  24  and  26 , may be provided within body portion  14  to prevent escape of gases out of body cavity BC and to seal about prior art surgical instrument  10 . In order to pressurize and thereby create a working space within body cavity BC, a gas port  28  is provided on body portion  14  for receipt of a source of gas or insufflation fluid  30 . Source of insufflation fluid  30  provides an inert, non-toxic gas such as, for example, carbon dioxide to expand and create a working space within body cavity BC. A valve  32  is provided on gas port  28  to control the flow of gas into body cavity BC. 
         [0034]    Prior art surgical instrument  10  generally includes a handle or body portion  34  having an elongate tubular member  36  extending distally from body portion  34 . An end effector  40  is located on a distal end  38  of elongate tubular member  36  in order to perform surgical operations on tissues located within body cavity BC. In prior art surgical instrument  10 , end effector  40  includes a staple cartridge  42  and an anvil member  44  movably mounted relative to staple cartridge  42 . Anvil member  44  is movable between an open position spaced from staple cartridge  42  to a closed position wherein anvil member  44  is in close cooperative alignment staple cartridge  42 . While end effector  40  is illustrated as including staple cartridge  42  and anvil member  44 , other types of end effectors such as, for example, cutters, graspers, biopsy devices, electrocautery devices, etc. are also contemplated for use in prior art surgical instrument  10 . An actuator or trigger  46  is provided on body portion  34  and is operable to move anvil member  44  between the open and closed positions relative to staple cartridge  42 . A rotator cuff  48  is rotatably mounted on body portion  34  and is affixed to elongate tubular member  36 . Rotator cuff  48  is provided to rotate elongate tubular member  36 , and thus end effector  40 , in order to properly orient end effector  40  relative to the tissues being operated upon. 
         [0035]    In using the prior art surgical instrument  10  and prior art cannula  12  to perform surgical operation within body cavity BC, incision I is formed through body cavity wall BCW and cannula tube  16  is inserted through incision I such that prior art cannula  12  forms an access port into body cavity BC. Once prior art cannula  12  is properly positioned, valve  32  is opened to allow insufflation gases to flow from source of insufflation fluid  30  through throughbore  18  and into body cavity BC in the direction of arrows A thereby expanding body cavity BC to create working space. As insufflation gases flow into body cavity BC, the pressure P 1  within body cavity BC is raised to a level greater than an external or ambient pressure P 2  outside of body cavity BC. 
         [0036]    Once body cavity BC has been properly expanded and pressurized to pressure P 1 , prior art surgical instrument  10  is manipulated such that end effector  40  and elongate tubular member  36  are inserted through seals  24  and  26  and throughbore  18  in prior art cannula  12 . Once end effector  40  has been extended out of distal end  22  of cannula tube  16 , the desired surgical operation is performed within body cavity BC. 
         [0037]    Because pressure P 1  within body cavity BC is greater than pressure P 2  outside of body cavity BC, there exists a pressure differential between end effector  40  located within body cavity BC and the remainder of prior art surgical instrument  10  such as, body portion  34 , located outside of body cavity BC. Insufflation gases located within body cavity BC may, in some instances, be forced proximally through prior art surgical instrument  10  in the direction of arrows B and escape into body portion  34  and out between gaps between rotator cuff  48  and body portion  34  and trigger  46  and body portion  34 . While prior art surgical instrument  10  typically includes various seals (not shown) to prevent escape of the insufflation gases, these seals may still leak, particularly as internal components of prior art surgical instrument  10  move relative to the seals during operation. As the insufflation gases move proximally through prior art surgical instrument  10 , the insufflation gases tend to draw or siphon bodily fluids and tissue particles into and proximally through end effector  40  and elongate tubular member  36  thereby contaminating and in some instances potentially damaging internal components of prior art surgical instrument  10 . Additionally, prior art surgical instrument  10  may provide a pathway for escape of the insufflation gases thereby lowering pressure P 1  within body cavity BC. 
         [0038]    Referring now to  FIG. 2 , there is disclosed a pressurized surgical instrument  50  for use with prior art cannula  12  to perform a surgical operation within body cavity BC. Pressurized surgical instrument  50  is designed to inhibit the prevent escape of insufflation gases out of body cavity BC through pressurized surgical instrument  50 . Pressurized surgical instrument  50  generally includes a handle or body portion  52  having an elongate tubular member  54  extending distally from body portion  52 . An end effector  56  is mounted on a distal end  58  of elongate tubular member  54  and includes a staple cartridge  60  and an anvil member  62  movably mounted relative to staple cartridge  60 . A trigger or actuator  64  is provided to move anvil member  62  from an open position spaced from staple cartridge  60  to a closed position adjacent staple cartridge  60 . While pressurized surgical instrument  50  is disclosed as including end effector  56 , other end effectors such as those noted hereinabove with respect to prior art surgical instrument  10  may be provided. A rotator cuff  66  is rotatably mounted on a distal end  68  of body portion  52  and is affixed to elongate tubular member  54  in order to properly orient end effector  56  relative to tissues being operated upon. 
         [0039]    In order to prevent the escape of insufflation gases out of body cavity BC through pressurized surgical instrument  50 , pressurized surgical instrument  50  includes a pressurization mechanism  70  which is provided to generate a pressure P 3  ( FIG. 5 ) within elongate tubular member  54  which is greater than or equal to pressure P 1  within body cavity BC. The generation of pressure P 3  within elongate tubular member  54  prevents the escape of insufflation gases and siphoning of bodily fluids and tissues into pressurized surgical instrument  50 . A primary sensor  72  is located adjacent distal end  58  of elongate tubular member  54  and is provided to detect pressure P 1 . A sensor cable  74  extends through elongate tubular member  54  from primary sensor  72  to pressurization mechanism  70  in a manner described in more detail hereinbelow. 
         [0040]    Referring now to  FIG. 3 , as noted hereinabove, actuator  64  is movably mounted relative to body portion  52 . Actuator  64  is mounted to body portion  52  at pivot  76 . In order to actuate end effector  56  ( FIG. 2 ) a control rod  78  extends from an internal end  80  of actuator  64  and through elongate tubular member  54 . A proximal end  82  of control rod  78  is movably affixed to internal end  80  by studs  84  formed on internal end  80 . A distal end (not shown) of control rod  78  is affixed to end effector  56  to actuate end effector  56 . As further noted hereinabove, surgical instruments typically include various seals to assist in preventing the escape of gases therethrough. Pressurized surgical instrument  50  includes a seal  86  located at a proximal end  88  of elongate tubular member  54  to seal about control rod  78 . 
         [0041]    Pressurization mechanism  70  includes an internal pressure monitoring and regulation circuit or controller  90  which is provided to receive a signal sent by primary sensor  72  and determine pressure P 3  to be generated by pressurization mechanism  70 . Controller  90  includes a comparison sensor  95  and a microprocessor or analog control circuit to compare pressure body cavity pressure P 1  sensed by primary sensor  72  to ambient pressure P 2  detected by the sensor  95  in controller  90  external of body cavity BC. Controller  90  triggers a valving or pressure regulation mechanism to generate and maintain internal surgical instrument pressure P 3  at a level greater than or equal to pressure P 1 . A proximal end  92  of sensor cable  74  is connected to controller  90  to transmit the signal received from primary sensor  72 . 
         [0042]    Pressurization mechanism  70  additionally includes a self-contained gas canister  94  positioned within body portion  52 . Self-contained gas canister  94  contains a carbon dioxide insufflation gas. A valve  96  is provided on self-contained gas canister  94  to regulate the flow of gas out of self-contained gas canister  94  and through pressurized surgical instrument  50 . A valve cable  98  extends from controller  90  to valve  96 . Controller  90  compares pressure P 1  detected by primary sensor  72  and triggers valve  96  to open in order to provide gas pressure P 3  within pressurized surgical instrument  50 . Self-contained gas canister  94 , valve  96  and valve cable  98  form a pressure delivery system  100  of pressurization mechanism  70 . 
         [0043]    Pressure delivery system  100  additionally includes a pressure tube  102  having a first end  104  connected to valve  96  and a second end  106  which is connected to a proximal end of  108  of elongate tubular member  54  distally of seal  86 . Specifically, a collar  110  is in fluid communication with elongate tubular member  54  through a plurality of ports  112  formed in collar  110 . Second end  106  of pressure tube  102  is affixed to collar  110  to transmit pressurization gases or insufflation fluids from self-contained gas canister  94  to elongate tubular member  54 . 
         [0044]    Referring for the moment to  FIG. 4A , as noted hereinabove, primary sensor  72  is located adjacent distal end  58  of elongate tubular member  54 . A distal end  114  of sensor cable  74  is affixed to primary sensor  72 . Primary sensor  72  may be affixed to an inner surface  116  of elongate tubular member  54  or, alternatively, primary sensor  72  may be formed, molded, or otherwise positioned internally of a wall  118  of elongate tubular member  54 . Additionally, sensor cable  74  may also extend internally of wall  118  from primary sensor  72  proximally to proximal end  88  of elongate tubular member  54 , as shown in  FIG. 4B . It should be noted that, while primary sensor  72  is disclosed as being located within elongate tubular member  54 , primary sensor  72  can be located elsewhere within pressurized surgical instrument  50 . 
         [0045]    Referring now to  FIGS. 2-6 , and initially with regard to  FIG. 2 , the use of pressurized surgical instrument  50  will now be described. Prior art cannula  12  is inserted through incision I formed through body cavity wall BCW such that distal end  22  of prior art cannula  12  is located within body cavity BC. Thereafter, valve  32  is opened to allow gases to flow from source of insufflation fluid  30  through gas port  28  and out distal end  22  of prior art cannula  12 . The gas flows in the direction of arrows A to insufflate body cavity BC to pressure P 1  which is greater than ambient pressure P 2  and to create a working space within body cavity BC. Similar to prior art surgical instrument  10  described hereinabove, when pressurized surgical instrument  50  is in a static or non-actuated condition, insufflation gases can flow proximally through pressurized surgical instrument  50  in the direction of arrows B thereby siphoning insufflation fluids and body tissues into and through pressurized surgical instrument  50 . 
         [0046]    Referring now to  FIGS. 3 and 5 , upon actuation of pressurization mechanism  70 , controller  90  ( FIG. 3 ) receives a signal proportional to pressure P 1  detected by primary sensor  72  and compares it to pressure P 3  within pressurized surgical instrument  50 . Should pressure P 1  be greater than P 3 , controller  90  signals pressure delivery system  100 , including valve  96 , to open allowing high pressure gases to flow from self-contained gas canister  94  through pressure tube  102  to collar  110  at proximal end  108  of elongate tubular member  54 . This initiates the flow of gases distally in the direction of arrows C through pressurized surgical instrument  50 . As gases flow distally in the direction of arrows C through pressurized surgical instrument  50 , the pressure within pressurized surgical instrument  50  is equalized such that pressure P 3  within pressurized surgical instrument  50  is equal to pressure P 1  within body cavity BC thereby preventing any flow or siphoning of bodily fluids or tissues proximally through pressurized surgical instrument  50 . It should be noted that controller  90  can be adjusted to provide a pressure P 3  which is equal to pressure P 1  or greater than pressure P 1 . 
         [0047]    Referring now to  FIG. 6 , and as noted hereinabove, controller  90  can be adjusted to provide a pressure P 3  which is greater than pressure P 1  within body cavity BC. This is desirable where additional insufflation fluid may be necessary to maintain body cavity BC in the insufflated condition and prevent against loss of insufflation gases through additional access ports or prior art cannulas  12 . In this instance, controller  90  triggers pressure delivery system  100  to provide a flow of high pressure gases, having a pressure P 3  greater than P 1 , in the direction of arrows C through pressurized surgical instrument  50  and out distal end  58  of elongate tubular member  54  and into body cavity BC. 
         [0048]    In this manner, pressurized surgical instrument  50  prevents siphoning of bodily fluids and tissues back through pressurized surgical instrument  50  and can be utilized to provide additional insufflation fluids within body cavity BC to offset any losses through other access ports. 
         [0049]    Referring now to  FIGS. 7-10 , and initially with respect to  FIG. 7 , there is disclosed another alternative embodiment of a pressurized surgical instrument  120  for use with prior art cannula  12  to perform a surgical operation within body cavity BC. Like pressurized surgical instrument  50  described hereinabove, pressurized surgical instrument  120  is designed to prevent escape of insufflation gases out of the cavity BC and thus prevent siphoning of any bodily fluids or tissues through pressurized surgical instrument  120 . The operational structure of pressurized surgical instrument  120  is similar to that of pressurized surgical instrument  50  and generally includes a handle or body portion  122  having an elongate tubular member  124  extending distally from body portion  122 . An end effector  126  is mounted on a distal end  128  of elongate tubular member  124  and includes a staple cartridge  130  and an anvil member  132 . Anvil member  132  was movably mounted relative to staple cartridge  130 . A trigger or actuator  134  is provided to move anvil member  62  from an open position spaced from staple cartridge  130  to a closed position adjacent staple cartridge  130 . A rotator cuff  136  is rotatably mounted on a distal end  138  of body portion  132  to orient end effector  126  relative to tissue being operated upon. 
         [0050]    Pressurized surgical instrument  120  includes a pressurization mechanism  140  to prevent the escape of insufflation gases out of body cavity BC through pressurized surgical instrument  120 . Pressurization mechanism  140  is provided to generate a pressure P 4  ( FIG. 9 ) within elongate tubular member  124  which is greater than or equal to pressure P 1  within body cavity BC. A primary sensor  142  is located adjacent distal end  128  of elongate tubular member  124  and is provided to detect pressure P 1  in the manner described hereinabove. A sensor cable  144  extends through elongate tubular member  124  from primary sensor  142  to pressurization mechanism  140 . Similar to primary sensor  72  and sensor cable  74  in pressurized surgical instrument  50 , primary sensor  142  and sensor cable  144  may be provided on an inside of elongate tubular  124  or may be contained within a wall of elongate tubular member  124 . 
         [0051]    Referring now to  FIG. 8 , actuator  134  is movably mounted relative to body portion  122  at a pivot  146 . A control rod  148  extends from an internal end  150  of actuator  134  through elongate tubular member  124  to end effector  126 . Translation of control rod  148  through elongate tubular member  124  by actuation of actuator  134  moves anvil member  132  between the open and closed positions relative to staple cartridge  130  in a known manner. A proximal end  152  of control rod  148  is secured to internal end  150  of actuator  134  by studs  154 . A seal  156  is provided within a proximal end  158  of elongate tubular member  124  to minimize escape of insufflation gases out of body cavity BC through elongate tubular member  124 . 
         [0052]    Pressurizing mechanism  140  additionally includes a pressure delivery system  160  incorporating a pressurizing pump  162 . Pressurizing pump  162  is provided to generate pressure P 4  which is greater than or equal to pressure P 1  located within body cavity BC. Pressure delivery system  160  additionally includes a pressure tube  164  having a proximal end  166  connected to pressurizing pump  162  and a distal end  168  which is connected to a collar  170  provided on proximal end  158  of elongate tubular member  124 . Collar  170  is located distally of seal  156  and includes a plurality of ports  172  which are in fluid communication within an interior of elongate tubular member  124 . 
         [0053]    Pressurizing pump  162  can be powered by a variety of means such as, for example, internal batteries, external power sources, etc. Additionally, pressurizing pump  162  can draw its pressurizing fluid from external air sources in the instance where pressure P 4  is to be equal to pressure P 1  or maybe connected to an external source of low pressure insufflation fluids when it is desired to generate pressure P 4  greater than pressure P 1 . Pressure delivery system  160  additionally includes a draw tube  174  having a first end  176  connected to pressurizing pump  162  and a second end  178  connected to an external source of insufflation fluids. An external tube  180  is provided for connection to the external source of insufflation fluids and is connected to second end  178 . A bushing  182  may be provided to connect second end  178  of draw tube  174  to external tube  180 . 
         [0054]    Pressurization mechanism  140  additionally includes a controller  184  which functions substantially identical to controller  90  described hereinabove with respect to pressurized surgical instrument  50 . A proximal end  186  of sensor cable  144  is connected to controller  184  to transmit a signal detected by primary sensor  142 . A pump cable  188  extends between controller  184  and pressurizing pump  162 . Controller  184  receives a signal from primary sensor  142  and sends an instructional signal to pressurizing pump  162  in order to generate the desired pressure P 4 . 
         [0055]    Referring now to  FIGS. 7 through 10 , the use of pressurizing mechanism  140  to generate pressures within pressurized surgical instrument  120  will now be described. Cannula  12  is positioned through body cavity wall BCW in the manner described hereinabove and body cavity BC is insufflated to a pressure P 1  to create a working space. Thereafter, pressurized surgical instrument  120  is manipulated through cannula  12  such that end effector  126  is positioned within body cavity BC. 
         [0056]    Referring initially to  FIG. 7 , in the initial or nonactivated state, insufflation gases are forced into body cavity BC through prior art cannula  12  in the direction of arrows A. When pressurizing mechanism  140  is not activated pressure P 1  within body cavity BC is greater than pressure P 2  outside body cavity BC thereby allowing insufflation gases to flow in the direction of arrows B through pressurized surgical instrument  120 . As noted hereinabove, the escape of insufflation gases in the direction of arrows B causes a drawing or siphoning effect bowling bodily fluids and tissues into pressurized surgical instrument  120 . 
         [0057]    Referring now to  FIGS. 8 and 9 , when it is desired to prevent siphoning of bodily fluids through pressurized surgical instrument  120 , pressurized surgical instrument  120  is activated such that primary sensor  142  detects pressure P 1  within body cavity BC. The signal detected by primary sensor  142  is sent to pressurization mechanism  140  through sensor cable  144 . Specifically, the signal is sent to controller  184  of pressurization mechanism  140  which then sends a signal to pressure delivery system  160 . Pressurizing pump  162  is activated and draws fluid through draw tube  174  and forces the fluid through pressure tube  164  into elongate tubular member  124 . Fluid pressure is driven along lines of arrows C to generate pressure P 4  within elongate tubular member  124  of pressurized surgical instrument  120 . As shown, generated pressure P 4  is equal to body cavity pressure P 1  which equalizes pressures within pressurized surgical instrument  120  to prevent any siphoning or escape of bodily fluids or tissues. 
         [0058]    Referring now to  FIG. 10 , in the event it is desirable to provide additional insufflation fluid into body cavity BC, the signal sent from controller  184  to pressurizing pump  162  is such that pressurizing pump  162  generates a pressure P 4  greater than body cavity pressure P 1 . As shown, pressurizing gases generated by pressurizing pump  162  travel through pressurized surgical instrument  120  in the direction of arrows C and exit distal end  128  of elongate tubular member  124  and into body cavity BC. 
         [0059]    In this manner, pressurized surgical instrument  120  incorporates an internal pressurizing pump  162  within pressure delivery system  160  of pressurizing mechanism  140  to either balance the pressures within pressurized surgical instrument  120  or generate sufficient pressure to provide additional sources of insufflation fluid into body cavity BC. 
         [0060]    Referring now to  FIGS. 11 through 14 , there is disclosed another embodiment of a pressurized surgical instrument  190 . Pressurized surgical instrument  190  generally includes a handle or body portion  192  and an elongate tubular member  194  extending distally from body portion  192 . An end effector  196  is provided on a distal end  198  of elongate tubular member  194 . End effector  196  includes a staple cartridge  200  and an anvil member  202  movably mounted to staple cartridge  200 . A trigger or actuator  204  is movably mounted on body portion  192  and is provided to move anvil member  202  from an open position spaced from staple cartridge  200  to a closed position adjacent staple cartridge  200 . A rotator cuff  206  is rotatably mounted on a distal end  208  of body portion  192  and is rotatable to orient end effector  196  relative to tissues being operated upon. 
         [0061]    Pressurized surgical instrument  190  includes a pressurization mechanism  210  to prevent the escape of insufflation gases and siphoning of bodily fluids through pressurized surgical instrument  190 . A primary sensor  212  is positioned adjacent distal end  198  of elongate tubular member  194  and a sensor cable  214  extends between primary sensor  212  and pressurization mechanism  210 . It should be noted that, similar to the above embodiments, primary sensor  212  and sensor cable  214  may be contained within a wall (not shown) of elongate tubular member  194 . 
         [0062]    In contrast to the previously disclosed embodiments, pressurized surgical instrument  190  utilizes an external source  216  of high pressure insufflation gases. A supply tube  218  is provided and extends from external source  216  and is connected to a pressure delivery system  220  provided within body portion  192  in the manner described in more detail hereinbelow. 
         [0063]    Referring to  FIG. 12 , actuator  204  is movably mounted to body portion  192  at a pivot  222 . A control rod  224  extends through elongate tubular member  194  and is connected to an internal end  226  of actuator  204  at its proximal end  228 . Studs  230  formed on internal end  226  secure proximal end  228  of control rod  224  to actuator  204 . A seal  232  is provided in a proximal end  234  of elongate tubular member  194  to assist in the prevention of escape of insufflation gases. 
         [0064]    In this embodiment, pressure delivery system  220  generally includes a valve  236  incorporating a fitting  238  for releasable attachment to supply tube  218 . A pressure tube  240  is provided and extends between valve  236  and elongate tubular member  234 . Specifically a proximal end  242  of pressure tube  240  is connected to valve  236  and a distal end  244  of pressure tube  240  is connected to a collar  246  provided about proximal end  234  of elongate tubular member  194 . Collar  246  is in fluid communication with elongate tubular member  194  through a series of ports  248 . 
         [0065]    Pressurization mechanism  210  includes a controller  250  which is substantially similar to those controllers described hereinabove with regard to pressurized surgical instruments  50  and  120 . A proximal end  252  of sensor cable  214  is connected to controller  250  to transmit a signal comparable to the pressure detected by primary sensor  212 . A valve cable  254  is provided and has a first end  256  connected to controller  250  and a second end  258  connected to valve  236 . Controller  250  receives signals sent through sensor cable  214  and transmits a signal along valve cable  254  to control the operation of valve  236 . 
         [0066]    Referring now to  FIGS. 11-14 , and initially with regard to  FIG. 11 , the operation of pressurized surgical instrument  190  will now be described. Cannula  12  is inserted through an incision I formed through body cavity wall BCW and body cavity BC is insufflated to a pressure P 1  to create a working space within body cavity BC. Thereafter, pressurized surgical instrument  190  is manipulated through cannula  12  to position end effector  196  within body cavity BC. As with prior examples, prior to activation of pressurization mechanism  210 , insufflation fluids may flow-through pressurized surgical instrument  190  in the direction of arrows B thereby creating a siphoning effect drawing bodily fluids and tissue into pressurized surgical instrument  190 . 
         [0067]    Referring now to  FIGS. 12 and 13 , upon activation of pressurization mechanism  210 , primary sensor  212  detects pressure P 1  and sends a signal along sensor cable  214  to controller  250 . Controller  250  then sends a signal via valve cable  254  to valve  236 . Depending upon the desired state of pressurized surgical instrument  190 , valve  236  is opened to receive external source  216  of high pressure insufflation fluid via supply tube  218  and allow the insufflation fluids to flow-through pressure tube  240  to collar  246 . Valve  236  is opened to a degree which allows a pressure P 5 , equal to pressure P 1  within body cavity BC, to pass through and into pressure tube  240 . The high pressure insufflation fluids flow through ports  248  and into elongate tubular member  194 . The insufflation fluids flow distally in the direction of arrows C to equalize pressure within pressurized surgical instrument  190 . 
         [0068]    Referring to  FIG. 14 , in the event it is desired to utilize external source  216  of insufflation fluids to provide additional insufflation fluid into body cavity BC, valve  236  is opened to a degree which allows pressure P 5  to be greater than pressure P 1  located within body cavity BC. In this instance, insufflation fluids flow in the direction of arrows C completely through pressurized surgical instrument  190  and into body cavity BC. 
         [0069]    In this manner, pressurized surgical instrument  190  can be equalized to pressure P 1  contained within body cavity BC or can be pressurized to a degree higher than pressure P 1  in body cavity BC and utilized to provide an additional source of insufflation gases. Additionally, by utilizing an external source  216  of pressurized insufflation fluids, pressurized surgical instrument  190  can receive and essentially unlimited supply of pressurization gases. 
         [0070]    As discussed above, pressurized surgical instruments  50 ,  120  and  190  incorporate provisions to equalize pressures within the respective surgical instruments relative to pressures inside an insufflated body cavity BC, as well as, provide an additional source of insufflation fluids into body cavity BC to offset losses through other access ports. 
         [0071]    It will be understood that various modifications may be made to the embodiments disclosed herein. For example, the disclosed pressurization mechanisms, primary sensors and sensor cables may be incorporated into other instruments utilized in endoscopic and/or laparoscopic procedures such as, for example, endoscopic biopsy devices, visualization devices, etc. Further, and as noted hereinabove, the primary sensor may be located at various locations within the surgical instrument so as to detect pressures within the surgical instrument at various points. Additionally, seals may be provided at the openings in the surgical instruments body portions which receive the actuators, rotator cuff and any other external devices and the entire surgical instrument including the body portion, as well as the elongate tubular member portion, may be pressurized. Therefore, the above description should not be construed as limiting, but merely as exemplifications of particular embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.
There are provided pressurized surgical instruments for use in pressurized surgical environments. The pressurized surgical instruments include pressurizing systems for maintaining a neutral or positive pressure flow within the surgical instrument during use. The pressurizing systems include a primary sensor for detecting the pressure of the surgical environment and a pressurizing mechanism for balancing the pressure of the surgical instrument with the surgical environment. The pressurizing mechanism includes a controller to receive and compare the signal sent from the primary sensor to the ambient or internal instrument pressure and a pressure delivery system to provide positive pressure to the interior of the surgical instrument in response to a signal received from the controller. The sources of pressure for the pressure delivery systems may be external or self contained within the surgical instrument.