Abstract:
A diameter reduction mechanism for a fixed seal trocar employing a movable reduction member pivotally connected with a housing. The housing is adapted to be mounted on a proximal end of a valve assembly of the trocar. The reduction member defines a hole aligned with a passageway defmed by the trocar. The hole defines an operable area less than an operable area defined by the passageway. The diameter reduction mechanism is configured for the ease of selectively employing the reduction member between a first position reducing the operable area of the passageway and a second position wherein the reduction member is clear of the passageway. The first position is configured to limit excessive off-axis and angular movements of small diameter surgical instruments and the second position is configured to accommodate an unrestricted use of large diameter surgical instruments in the passageway.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This case claims priority to Applicant&#39;s U.S. Provisional Application 60/241,665, filed Oct. 19, 2000, the entire contents of which are hereby incorporated by reference. 
     
    
     BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    The present disclosure relates to a mechanism for controlling the operable area of a passageway defined in a valve assembly of a trocar. More particularly, the present disclosure relates to a diameter reduction mechanism that is removably positionable over the passageway of the trocar to restrict the movement of small diameter surgical instruments to a reduced operable area of the passageway without sealing with the trocar and pivot clear of the passageway to accommodate large diameter surgical instruments. 
         [0004]    2. Background of Related Art 
         [0005]    Trocar valve assemblies are configured to provide a fluid tight sealing system before, during, and after a surgical instrument is entered through the trocar during minimally invasive surgical procedures. Sealing systems, such as a valve assembly for a passageway defined by a trocar connected with a cannula include an outer seal which can be fixed or floating, in combination with additional inner seals. Fixed outer seals are limited by their ability to sustain a seal when smaller surgical instruments are moved off-axis, away from and generally parallel to the central longitudinal axis, towards the inside circumference of the cannula. Fixed seals are also limited by their ability to sustain their integrity when small diameter surgical tool angulation is employed. These extreme ranges of motion of smaller diameter surgical instruments within the cannula can create a “cat eye” or crescent shaped gap in the fixed seal that can result in a loss of seal integrity. Additional problems include the ability of a sealing system to be sufficiently flexible to maintain its integrity when both small diameter and large diameter surgical instruments are used. 
         [0006]    Devices to restrict the diameter of a passageway in a trocar housing generally require a complex additional mechanism to be positioned on the proximal end of the trocar housing that restricts the range of motion of small surgical instruments and include additional seals or replace seals of the valve assembly with seals configured for small surgical instruments. These diameter reducing devices, however, typically require the disassembly and assembly of the proximal end of the trocar to adjust for the varying sizes of diameter reduction devices. 
         [0007]    A continuing need exists for a diameter reducing structure that can limit parallel off-axis as well as angular movements of small diameter surgical instruments and accommodate larger diameter surgical instruments without disassembling the proximal end of the trocar. 
       SUMMARY 
       [0008]    A diameter reduction mechanism is provided for assisting the valve assembly of a trocar in maintaining a seal. The diameter reduction mechanism includes a housing and a movable limiter. The limiter is diametrically positionable over the passageway to control the parallel off-axis and angular movements of smaller diameter surgical instruments. The limiter includes a locking mechanism and a pivot. The locking mechanism is adapted for use by a surgeon to readily lock the limiter in position over the passageway and to unlock and move the limiter clear of the passageway. Once the limiter is clear of the passageway, larger diameter surgical instruments are freely positionable within the passageway without any further adjustments by the operator. 
         [0009]    The invention, together with attendant advantages, will be best understood by reference to the following detailed description of the invention when used in conjunction with the figures below. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0010]    Preferred embodiments of the presently disclosed diameter reduction structure fixed trocar seal are described herein with reference to the drawings, wherein: 
           [0011]      FIG. 1  is a top view of one preferred embodiment of a diameter reduction mechanism for a fixed trocar seal constructed in accordance with the present disclosure; 
           [0012]      FIG. 2  is a cross-sectional side view of the diameter reduction mechanism for the fixed trocar seal of  FIG. 1  along lines A-A; 
           [0013]      FIG. 3  is a cross-sectional side view of the diameter reduction mechanism for the fixed trocar seal of  FIG. 1  along lines B-B; 
           [0014]      FIG. 4  is a close-up of a partial cross-sectional side view of the diameter reduction mechanism for the fixed trocar seal of  FIG. 1  along lines C-C; 
           [0015]      FIG. 5  is a close-up of detail D of a pivot assembly of the diameter reduction mechanism for the fixed trocar seal of  FIG. 2 ; 
           [0016]      FIG. 6  is a close-up of detail E of the interface between the valve assembly and the diameter reduction mechanism for the fixed trocar seal of  FIG. 2 ; and 
           [0017]      FIG. 7  is a perspective view of the top of the diameter reduction mechanism for the fixed trocar seal of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS  
       [0018]    The present disclosure contemplates the introduction into a body of a patient a trocar adapted for receiving all types of surgical instruments including clip appliers, graspers, dissectors, retractors, staplers, laser fibers, endoscopes, as well as electrosurgical cutting, coagulating, and ablation devices, and the like. All such objects are referred to herein as “instruments”. 
         [0019]    Referring now in specific detail to the drawings in which like referenced numerals identify similar or identical elements throughout the several views, and initially to FIGS.  1 - 3 , a novel diameter reduction mechanism for a fixed trocar seal  10  is shown constructed in accordance with the present disclosure and intended to be configured as an integral portion or an attachment to a conventional trocar assembly  100 . Trocar assembly  100  includes valve assembly  120 , end cap  130 , and cannula (not shown). Trocar assembly  100  defines a passageway  150  aligned with a central longitudinal axis-X. Passageway  150  defines a first operable area. Valve assembly  120  is configured to provide a seal between a cavity formed in the patient and the outside atmosphere during and subsequent to insertion of an instrument through the cannula. 
         [0020]    Diameter reduction mechanism for fixed trocar seal  10  includes a housing  20  and a limiter  50 . Housing  20 , in one preferred embodiment is an integral and proximal portion of valve assembly  120  of trocar  100 . In another preferred embodiment, housing  20  is a tubular shaped ring adapted for being removably connected to a proximal end of valve assembly  120 . Housing  20  includes a tubular wall  26  having a distal end portion  22  and a proximal end portion  24  aligned with the longitudinal axis-X. 
         [0021]    Referring now to  FIGS. 2-4  and  6 , distal end portion  22  of tubular wall  26  includes an inwardly and radially extending protuberance  23  configured to engagingly mate and lock with an annular lip  133  positioned on end cap  130  of valve assembly  120 . 
         [0022]    As shown in  FIGS. 1 ,  2  and  5 , proximal end portion  24  includes a receptacle  25  having a pair of opposed notches  27  configured for the pivoting of limiter  50  and a diametrically opposed lip  28  positioned on wall  26 . Lip  28  has an arcuate shaped portion extending outwardly and radially from wall  26  with a distal facing generally flat portion. 
         [0023]    Referring now to  FIGS. 1-3  and  5 - 6 , in one preferred embodiment, diameter reduction mechanism  10  in a first position includes housing  20  lockingly engaged with valve assembly  120  and limiter or reduction member  50  extending diametrically over passageway  150  and valve assembly  120 . Limiter  50  includes a first end  52  being pivotally connected to a receptacle  25  of housing  20  and a second end  54  being engaged and locked with lip  28 . An axis-Z is defined perpendicular to limiter  50  and axis-Y that intersects axis-X. 
         [0024]    Limiter  50  has an elongate planar beam shape having a thickness in the direction of axis-X and a width in the direction of axis-Z. The width of limiter  50  can vary, but is approximately less than or equal to the diameter of passageway  150 . A hole or opening  71  is centrally positioned on limiter  50  and aligned with the longitudinal axis-X. Limiter  50  also includes an annular recess  59  positioning hole  71  distal to first end  52  and second end  54  such that a proximal side of a rim  72  of hole  71  is positioned approximately equal to or below the proximal edge of valve assembly  120 . 
         [0025]    In  FIGS. 1-3  and  5 , first end  52  can include interfaces such as a hinge, a threaded connection, or a slide, such that the limiter  50  can pivot about notch  27  of receptacle  25 . In one preferred embodiment first end  54  includes a pair pins  55  perpendicular to axis-Y positionable within notches  27 . Pins  55  have a controlled tolerance to fit tightly within notches  27  for a pure rotational hinge type movement or notches  27  can include a predetermined amount of play or bias such that limiter  50  can translate a controlled distance along axis-Y, for example, or pivot angularly within a plane Z-Y formed by the intersection of axes Z and Y. 
         [0026]    Referring now to  FIGS. 1 ,  2  and  7 , second end  54  includes a locking mechanism  60  having a first cantilevered element  62  extending along axis-Y with a second cantilevered element  64  and a third cantilevered element or locking element  66  extending distally therefrom and generally parallel to longitudinal axis-X. A distal end of element  66  includes a radially inwardly extending protuberance  67  configured for engagingly interfacing with lip  28  to lock limiter  50  in the first position. A fillet  63  extends between an edge  61  of element  62  and a distal end edge  65  of element  64 . Fillet  63  is ergonomically configured for the positioning of a limb or portion of a limb of a surgeon for the proximal movement or flexing of second end  54  to disengage protuberance  67  from lip  28 . 
         [0027]    Limiter  50  includes an interior portion  70  having a proximal first rim  72  and a distal second rim  74  defining hole  71  as well as an annular portion  78 . Rim  72  has a conical shape with a distally decreasing inside diameter and rim  74  has a conical shape with a distally increasing diameter. The conical shapes of rims  72  and  74  are advantageously configured to support a limited degree of small surgical instrument angulation. Hole  71  is aligned with the longitudinal axis-X in the first position and less than the inside diameter of passageway  150  by a predetermined amount, depending upon the desired application. Thus, hole  71  reduces the first operable area to a second operable area less than the first operable area. It is envisioned that diameter reduction mechanism for fixed trocar seal  10  can be provided in a variety of reducing diameters in a kit configuration having multiple limiters  50  and/or mechanisms  10  and be readily removed and replaced as an assembly without interrupting the integrity of the valve assembly. 
         [0028]    As shown in  FIGS. 1-3  and  7 , interior portion  70  includes an annular channel  76  extending proximally from the distal side of limiter  50 . Channel  76  is in apposition with rim  74  and defines rim  74  as a distally extending cantilevered element that provides a controlled degree of flexing or bias by rim  74  to urge instruments towards the central longitudinal axis. Annular portion  78  extends distally from interior portion  70 . Annular portion  78  has a distal end  79  configured for seating on a rim  139  of a proximal end of end cap  130 . Rim  139  defines a proximal portion of passageway  150  in conjunction with annular portion  78  in the first position. Annular portion  78  defines an inside diameter approximately equivalent to the proximal portion of passageway  150  defined by end cap  130 . Thus, limiter  50  in the first position is configured as a cross beam supported on ends  54  and  52  by housing  20  and by the positioning of annular portion  78  in direct contact with rim  139  of end cap  130 . Annular portion  78  provides structural support for limiter  50  and it precludes the misalignment of instruments while providing a non-sealing interface with passageway  150 . 
         [0029]    Limiter  50  is movably positioned on housing  20  such that when the surgeon desires to use instruments larger than the diameter of hole  71 , the limiter  50  can be readily pivoted out of the first position over passageway  150  by using the limb or the portion of the limb of the surgeon to pull proximally against fillet  63  or edge  61 . When limiter  50  is pivoted clear of passageway  150 , diameter reduction mechanism for fixed trocar seal  10  is in a second position. Limiter  50  in the second position, is preferably extending distally and parallel to the longitudinal axis-X, but it may include stops or be biased to a range of positions from extending proximally and generally parallel to the longitudinal axis-X to being parallel to axis-Y, for example. 
         [0030]    It is also envisioned that limiter  50  can be suitably configured for translation or angular movement with the X-Y plane such that limiter  50  can include a variable circumference configured to be aligned with axis-X that can be integral to or removably attached to limiter  50  to accommodate varying sized instruments without removing limiter  50  or diameter reduction mechanism for fixed trocar seal  10  from the trocar. 
         [0031]    Referring now to  FIG. 7 , in operation, diameter reduction mechanism for fixed trocar seal  10  is positioned over a proximal end of valve assembly  120  of trocar  100  and forwarded distally to engage and lock housing  20  with valve assembly  120 . Moving limiter  50  accommodates the selective changing of the operable area of passageway  150 . Limiter  50  in the first position is configured to limit the off axis movements as well as the angulation of small diameter surgical instruments less than or equal to the diameter of hole  71 . Limiter  50  is adapted to readily accommodate, with a single movement of edge  61  or fillet  63 , the movement of limiter  50  from the first position to the second position for the positioning of larger diameter surgical instruments. Limiter  50  is adapted for being readily replaced to the first position by the limb of the surgeon positioning second end  54  to suitably engage locking mechanism  60  to retain limiter  50  in the first position. 
         [0032]    Although the illustrative embodiments of the present disclosure have been described herein with reference to the accompanying drawings, it is to be understood that the disclosure is not limited to those precise embodiments, and that various other changes and modifications may be affected therein by one skilled in the art without departing from the scope or spirit of the disclosure. All such changes and modifications are intended to be included within the scope of the disclosure.