Abstract:
A surgical portal apparatus for use during a minimally invasive procedure includes a housing and a portal member extending distally from the housing. The housing and portal member combination defines a longitudinal axis. The portal member is sized to be positioned within tissue and has an opening at the distal end. The apparatus also has a pliable seal and a plurality of concentrically arranged piston members, disposed within the housing. The pistons are engageable with the pliable seal and are adapted for moving relative to the housing to control the diameter of a passage through the inner portion of the seal in response to the insertion of a surgical object.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present application claims the benefit of and priority to U.S. Provisional Application Ser. No. 61/081,473 filed on Jul. 17, 2008, the entire contents of which are incorporated herein by reference. 
    
    
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to a device, and a method of use thereof, for facilitating access to a patient&#39;s internal cavities during a surgical procedure. More particularly, the present disclosure relates to a surgical apparatus adapted for insertion into an incision in tissue, and for the sealed reception of one or more surgical objects, so as to form a substantially fluid-tight seal with both the tissue and the surgical object, or objects. 
     2. Background of the Related Art 
     Today, many surgical procedures are performed through small incisions in the skin, as compared to the larger incisions typically required in traditional procedures, in an effort to reduce trauma to the patient and recovery time. Generally, such procedures are referred to as “endoscopic”, unless performed on the patient&#39;s abdomen, in which case the procedure is referred to as “laparoscopic”. Throughout the present  disclosure, the term “minimally invasive” should be understood to encompass both endoscopic and laparoscopic procedures. During a typical minimally invasive procedure, surgical objects, such as surgical access devices, e.g., trocar and trocar assemblies, or endoscopes, are inserted into the patient&#39;s body through one or more incisions in tissue. 
     In general, prior to the introduction of the surgical object into the patient&#39;s body, insufflation gasses are used to enlarge the area surrounding the target surgical site to create a larger, more accessible work area. Accordingly, the maintenance of a substantially fluid-tight seal about the surgical object, or objects, is important, so as to prevent the escape of the insufflation gases and the deflation or collapse of the enlarged surgical work area. 
     To this end, various apparatus, including valves, seals and the like, are used during the course of minimally invasive procedures and are widely known in the art. However, a continuing need exists for an apparatus and associated seal for insertion in tissue that can accommodate a variety of differently sized surgical objects while maintaining the integrity of an insufflated workspace. 
     SUMMARY 
     Accordingly, the present disclosure provides a surgical portal apparatus with a seal assembly, which will allow a surgeon to efficaciously utilize instruments of varying diameter in a surgical procedure. The surgical portal apparatus includes a longitudinal opening to permit passage of a surgical object through the surgical portal apparatus. This seal assembly obviates the need for multiple adapters to accommodate  instruments of varying diameters by providing a seal with an adjustable opening. One embodiment is directed to a surgical portal apparatus having a housing, a portal member, a pliable seal, and a plurality of concentrically arranged pistons for use within the housing. The portal member extends from the housing, having a longitudinal axis defined therethrough. The portal member is dimensioned for positioning within tissue and defining an opening at a distal end. The piston members are engageable with the inner portions of the pliable seal and are adapted for movement relative to the housing to automatically control the diameter of the passage in response to insertion of a surgical instrument. 
     Each of the plurality of piston members acts upon the inner portions of a pliable seal. Each of the plurality of piston members is retained in a respective channel within the housing. The channels are configured to restrict movement of piston members in a radial direction. As the plurality of piston members are moved toward the center of the passage, the dimensioning of the passage is reduced. Each of the plurality of piston members is capable of moving independently of each other. The seal is fully open in the “at rest” position and is capable of fully closing to prevent the escape of fluid when activated. A duck-bill seal or zero seal may be used in conjunction to aid in preventing the escape of fluid during insertion and extraction of a surgical object. 
     The piston members are movable in response to the introduction of a surgical object to establish a substantial sealing relationship with the surgical object. Movement is accomplished by an actuation mechanism acting upon the piston members,  which in turn act against the pliable seal to decrease the diameter of the passage. The actuation mechanism includes a motor with resistive circuitry. The resistive circuitry is configured to detect an increased load on the motor and stops the motor when a specific load is detected. The motor releasably holds the load torque on the piston members in the second relative position causing a constant seal with the surgical object. 
     The surgical portal apparatus includes a sensor positioned within the housing. Located distal to the piston seal, the sensor adapted to be engaged by the surgical object during introduction of the surgical object within the housing. Engagement of the sensor activates the motor and thereby causes the movement of the piston members of the piston seal, from the first relative position to the second relative position. The sensor is capable of determining location and size of the inserted surgical object and moves the plurality of piston members accordingly. 
     In another embodiment, the surgical portal apparatus includes a manual actuation mechanism mounted to the housing and operatively connected to the plurality of piston members of the piston seal. A clinician engages and manipulates the manual actuation mechanism to selectively move the plurality of piston members between the first and second relative positions. In still another embodiment, the actuation mechanism includes an electromagnetic repulsion system capable of moving the plurality of piston members.  
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure, and together with a general description of the disclosure given above, and the detailed description of the embodiments given below, serve to explain the principles of the disclosure. 
         FIG. 1  is a right, perspective view of a trocar assembly and a seal assembly in accordance with the principles of the present disclosure; 
         FIG. 2  is a left, perspective view of a trocar assembly and a seal assembly in accordance with the principles of the present disclosure; 
         FIG. 3  is rear, perspective view of a trocar assembly and a seal assembly in accordance with the embodiment of  FIGS. 1-2 ; 
         FIG. 4  is a side, cross-sectional view of a trocar and seal assemblies in accordance with the present disclosure; 
         FIG. 5  is a side, cross-sectional view of a piston member for use with the trocar and seal assemblies in accordance with the embodiment of  FIGS. 1-4 ;  
         FIG. 6  is a top, partial internal view of the trocar and seal assemblies in accordance with the embodiment of  FIG. 4 ; 
         FIG. 7  is a top view in accordance with the embodiment of  FIG. 4 ; 
         FIG. 8  is a side, cross-sectional view of the trocar and seal assemblies in accordance with the present disclosure; 
         FIG. 9  is a top, internal view of the trocar and seal assemblies in accordance with the embodiment of  FIG. 8 ; 
         FIG. 10  is a top view in accordance with the embodiment of  FIG. 8 ; and 
         FIG. 11  is a flow chart illustrating one method of operation of the trocar assembly in accordance with the present disclosure. 
     
    
    
     Other features and advantages of the present disclosure will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principals of the present disclosure. 
     DETAILED DESCRIPTION   
     The seal assembly of the present disclosure provides a substantial seal between a body cavity of a patient and the outside atmosphere before, during, and after insertion of an instrument through a trocar assembly. Moreover by providing a fluid tight seal with each instrument when inserted, the seal assembly of the present disclosure is capable of accommodating instruments of varying diameters, e.g., from about 5 mm to about 15 mm. The flexibility of the present seal assembly greatly facilitates endoscopic surgery especially wherein a variety of instruments having differing diameters are often interchanged during a single surgical procedure. 
     The seal assembly contemplates the introduction and manipulation of various types of instrumentation, adapted for insertion through a trocar and/or trocar assembly, while maintaining a fluid tight interface about the instrumentation to preserve the atmospheric integrity of a surgical cavity from gas and/or fluid leakage. Specifically, the presently disclosed seal assembly substantively eliminates introduction and removal forces upon a surgical object relative to the seal housing axis and automatically adjusts the seal to compensate for off-center movement of the implement relative to the housing thereby minimizing contamination and leakage from the body cavity. Examples of instrumentation contemplated for use with the present disclosure include clip appliers, graspers, dissectors, retractors, staplers, laser probes, photographic devices, endoscopes and laparoscopes, tubes, and the like. Such instruments will be collectively referred to herein as “surgical objects”.  
     Referring now to the drawings, in which like reference numerals identify identical or substantially similar parts throughout the several views,  FIGS. 1-2  illustrate a seal assembly  100  in accordance with one embodiment of the present disclosure mounted to a trocar assembly  200 . Trocar assembly  200  may be any conventional trocar suitable for the intended purpose of accessing a body cavity and permit introduction of instruments therethrough. Trocar assembly  200  is particularly adapted for use in laparoscopic surgery where the peritoneal cavity is insufflated with a suitable gas, e.g., CO 2 , to raise the cavity wall from the internal organs therein. Trocar assembly  200  is typically used with an obturator assembly (not shown) which is a sharp pointed instrument positionable within the passageway of the trocar assembly  200 . The obturator assembly is utilized to penetrate the abdominal wall and then is subsequently removed from the trocar assembly  200  to permit introduction of the surgical instrumentation utilized to perform the procedure. 
     With reference to  FIGS. 1-2 , trocar assembly  200  includes trocar sleeve  202  and trocar housing  204  mounted to an end of the sleeve  202 . Any means for mounting trocar sleeve  202  to trocar housing  204  are envisioned including threaded arrangements, bayonet coupling, snap-fit arrangements, adhesives, etc. Trocar sleeve  202  and trocar housing  204  may also be integrally formed. Trocar sleeve  202  defines a longitudinal axis “a-a” extending along the length of sleeve trocar  202 . Trocar sleeve  202  further includes an internal longitudinal passage  206 , defined therein and dimensioned to permit passage of surgical instrumentation, therethrough. An aperture   212  is defined adjacent the distal end of trocar sleeve  202 , which extends through the wall of the trocar sleeve  202 . In the following description, as is traditional the term “proximal” refers to the portion of the instrument closest to the operator while the term “distal” refers to the portion of the instrument remote from the operator. 
     Aperture  212  permits passage of insufflation gases through trocar sleeve  202  during the surgical procedure. Trocar sleeve  202  may be formed of stainless steel or other rigid materials such as a polymeric material (or the like) and may be clear or opaque depending upon a particular purpose. The diameter of trocar sleeve  202  may vary, but, typically ranges from about 10 mm to about 15 mm for use with the seal assembly  100  of the present disclosure. Trocar housing  204  includes a port opening  214  defined therein, which is configured to receive luer fitting  216  therein (See  FIGS. 1 ,  2 , and  4 ). Luer fitting  216  is adapted for connection to a supply of insufflation gas and incorporates valve  218 , which selectively opens and closes the passage of the luer fitting  216  to regulate the flow of insufflation gas into the peritoneal cavity. 
     With continued reference to  FIGS. 1-4 , seal assembly  100  will be discussed in detail. Seal assembly  100  may be a separate component from trocar assembly  200  and, accordingly, may be adapted for releasable connection to the trocar assembly  200 . Alternatively, seal assembly  100  may be integrally incorporated as part of trocar assembly  200  forming a single unit. Seal assembly  100  includes a seal housing, having a piston seal  104  disposed therein. Seal housing  102  is generally dimensioned to  house the various internal cooperating components of the sealing assembly  100 . Seal housing  102  also defines central seal housing axis “b-b” which is preferably parallel to the axis “a-a” of trocar sleeve  202  and, more specifically, coincident with the axis “a-a” of the trocar sleeve  202 . Seal housing  102  incorporates two housing components, namely, first and second housing components  106  and  108 , respectively, which, when assembled, form the seal housing  102 . 
     As shown in  FIG. 4 , first housing component  106  defines inner or proximal guide wall  112  and outer cylindrical wall  114 , disposed radially outwardly therefrom. Proximal guide wall  112  defines a central passage  116 , which is configured to laterally confine an instrument (not shown) within the seal housing  102 . Proximal guide wall  112  further includes a flexible seal member  118  moveably disposed thereon and positioned to automatically engage an outer shaft or a surgical instrument upon insertion into central passage  116  as explained in more detail below. Outer wall  114  surrounds proximal guide wall  112  and extends distally therefrom. 
     Second housing component  108  of the seal housing  102  includes a transverse wall  122  and a cylindrical portion  124 . Cylindrical portion  124  is dimensioned to mate with the outer wall  114  of first housing component  106 , as best shown in  FIG. 2 . 
     Referring now to  FIGS. 3-5 , a piston seal  104  is mounted between the first housing component  106  and second housing component  108 . The assembled components  are held together by a series of screws or other, positive fastening means extending through circumferentially-disposed holes. Piston seal  104  includes a plurality of piston members  126  each including a piston body  128 , a tapered leading edge  130 , and an aft end  132 . (See  FIG. 5 ) The plurality of piston members  126  are anchored within the seal housing  102 , in a series of channels  146  that surround the periphery of the central passage  116 . As the plurality of piston members  126  are actuated, a force is applied to the outer most end of each of the plurality of piston members  126  causing each of the plurality of pistons members  126  to move within the channels  146 . The movement of the plurality of seal members  126  forces the seal member  118  to move between a first relative position and a second relative position. 
     Flexible seal member  118  may be fabricated from a single suitable elastomeric material having sufficient resiliency to stretch and form a seal about an inserted objected. Suitable materials include, but are not limited to polyurethane and copolyester. To minimize friction the elastomeric materials may be coated with silicon, the product polytetrafluoroethylene sold under the trademark TEFLON®, or the like. 
     The plurality of piston members  126  may be fabricated from any rigid material, including but not limited to plastic, metal, or composite. The plurality of piston members  126  may also be fabricated from a variety of different materials, e.g., the piston body  128  being made from a plastic material and the tapered leading edge  130  being  made from a composite material. To minimize friction, the plurality of piston members  126  and/or channels  146  may be made from or coated with a low friction material. 
     Prior to the insertion of a surgical instrument, the piston seal  104  is biased in an open orientation with the seal assembly  100  resting in a first position relevant to the proximal guide wall  112 . Upon the insertion of a surgical instrument, the plurality of piston members  126  automatically moves from the first position to a second position relative to the proximal guide wall  112 . The plurality of piston members are substantially closer to one another. The plurality of piston members  126  move automatically and, preferably, simultaneous, to encapsulate and engage the outer shaft of the surgical instrument and form a seal therearound. Instruments of varying diameters may be selectively inserted and withdrawn from the trocar without interrupting or compromising the integrity of the surgical cavity. The relative size and dimension of the central passage  116  automatically adjusts and regulates to adapt to surgical instrumentation of various sizes. 
     The actuation mechanism  110  moves the piston seal  104  between the first relative, or open position, and the second relative position engaging the surgical instrument to establish a sealing relation therewith or to close the piston seal  104 . The actuation mechanism  110  may include a motor  134  (See  FIG. 4 ) having an associated switch  140 , which regulates the operation of the plurality of piston members  126  the  switch  140  may be an “on/off” switch, which (when placed in the “on” position) configures the piston seal  104  for automatic engagement of a surgical instrument&#39;s shaft. The motor  134  may be any suitable miniature electric motor which may be battery powered. The motor output is operatively connected to the plurality of piston members  126  of piston seal  104  in a manner to effect linear movement of the piston members  126  between the first and second relative positions. Various electrical connections for connecting the plurality of piston members  126  to the motor  134  are envisioned and appreciated by one skilled in the art. 
     The force on the outer shaft of the surgical instrumentation may be applied by one or more resilient springs  150 . The springs  150  may be configured to extend relative to proximal guide wall  112  at different distances to accommodate off-center insertion or movement of the surgical instrument within the surgical cavity, e.g., some of the plurality of piston members  126  may travel a greater distance within channel  146  than some of the other plurality of piston members  126  relative to a respective proximal guide wall  112 . In this instance, some of the plurality of piston members  126  react against the surgical instrument without much travel while some of the plurality of piston members  126  are allowed to travel greater distances in order to contact the surgical instrument. The resilient springs  150  also act as guides to keep the plurality of pistons members  126  properly aligned.  
     The motor  134  may also be controlled by the interaction between the surgical instrumentation and a switch  140 . As the inserted instrument contacts the switch  140 , the switch  140  is triggered and activates the motor  134 . The motor  134 , in turn, applies a force via the actuation mechanism  110  to the plurality of piston members  126 . For example, in one embodiment, a motor  134  acts upon the ramp member  138  to cause ramp member  138  to rotate in a given direction. As the ramp member  138  rotates, the force from the motor  134  is translated through the resilient spring  128  to the piston members  126 , causing the plurality of piston members  126  to move between relative positions. As ramp member  138  rotates clockwise the piston seal  104  closes and when the ramp member  138  rotates counterclockwise the piston seal  104  opens. Ramp member  138  may include a scalloped or textured outer surface  138   a  (See  FIG. 3 ), which is dimensioned for a gripping engagement by the user to facilitate rotation. 
     A sensor  152  may be employed in place of a switch to regulate and control the movement of the plurality of piston members  126  for engaging and disengaging the surgical instrumentation. The sensor  152  is typically located at a position that is distal to the piston seal  104  within the seal housing  102  such that as the surgical instrument is introduced into the center passage  116 , the surgical instrument engages the sensor  152 . Once engaged, the sensor  152  activates the motor  134  causing the piston seal  104  to constrict around the surgical instrument. Thus, the plurality of piston members  126  move from a first relative position to a second relative position. The sensor  152  may be configured to interact with a central process unit to determine which of the plurality of  piston members  126  are actuated and the degree of actuation. Once the surgical instrument is removed from the central passage  116 , sensor  152  reactivates and the plurality of piston members  126  reset back to the first position to allow the surgical instrument to be removed without damage to the piston seal or requiring substantial force and which maintains the integrity of the surgical cavity. 
     Resistive circuitry  136  may be utilized to determine the desired or acceptable load place upon the outer shaft of the surgical instrument by the plurality of piston members  126 . For example, when the motor  134  operates, the motor  134  draws an electrical current that can be measured by resistive circuitry  136  associated with the motor  134 . It is envisioned that other alternative uses of resistive circuitry may be implemented to measure the load upon the motor  134 . Once a specific, predetermined load is detected by the resistive circuitry  136 , the motor  134  stops, which in turn stops the plurality of piston members  126  in the second relative position and holds the plurality of piston members  126  against the instrument shaft. 
     Although a motor  134  is disclosed as part of the actuation mechanism  110 , it is appreciated that the actuation mechanism  110  may be manually operated by a clinician. There are several ways a clinician can cause the linear movement of the plurality of piston members  126  and activate the piston seal  104 . One way is to manually rotate the ramp member  138  by the scalloped outer surface  138   a . Another alternative is a manual lever connected to an actuation mechanism reacting upon the pistons through various linkages (not shown).  
     In another embodiment, as shown in  FIG. 8 , the actuation mechanism  110  includes an electromagnetic repulsion system  148 . In this instance, at least two magnets are used in each piston channel  146  a first magnet  142 , having a first magnetic polarity, is attached to the piston member  126  and a second magnet  144  is attached to the wall  124  opposite the piston shaft end with a repelling magnetic polarity pointing towards the first magnetic polarity. As magnet  144  is electrically energized, magnet  142  is forced away from the wall  124 , causing the piston seal  104  to move from the first relative position to the second relative position. 
     While the invention has been particularly shown, and described with reference to the preferred embodiments, it will be understood by those skilled in the art that various modifications and changes in form and detail may be made therein without departing from the scope and spirit of the invention. Accordingly, modifications such as those suggested above, but not limited thereto, are to be considered within the scope of the invention.