the seal assembly of the present disclosure , either alone or in combination with a seal system internal to a cannula assembly , provides a substantial seal between a body cavity of a patient and the outside atmosphere before , during and after insertion of an instrument through the cannula assembly . moreover , the seal assembly of the present invention is capable of accommodating instruments of varying diameters , e . g ., from about 5 mm to about 15 mm , by providing a gas tight seal with each instrument when inserted . the flexibility of the present seal assembly greatly facilitates endoscopic surgery where a variety of instruments having differing diameters are often needed 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 cannula assembly while maintaining a fluid tight interface about the instrumentation to preserve the atmospheric integrity of a surgical procedure from gas and / or fluid leakage . specifically , the seal assembly accommodates angular manipulation of the surgical instrument relative to the seal housing axis . this feature of the present disclosure desirably minimizes the entry and exit of gases and / or fluids to / from the body cavity . examples of instrumentation 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 “ instruments or instrumentation ”. by virtue of its features , the seal assembly further defines a substantially reduced profile when assembled together and mounted to a cannula assembly . this reduced profile advantageously increases the working length of instruments introduced into the body cavity through the cannula assembly . in addition , the reduced profile permits enhanced angulation of a surgical instrument relative to the seal housing axis . 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 . referring now to the drawings , in which like reference numerals identify identical or substantially similar parts throughout the several views , fig1 - 5 illustrate the seal assembly 100 of the present disclosure mounted to cannula assembly 200 . cannula assembly 200 may be any conventional cannula suitable for the intended purpose of accessing a body cavity and permit introduction of instruments therethrough . cannula 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 . cannula assembly 200 is typically used with an obturator assembly ( not shown ) which is a sharp pointed instrument positionable within the passageway of the cannula assembly 200 . the obturator assembly is utilized to penetrate the abdominal wall and then subsequently removed from the cannula assembly 200 to permit introduction of the surgical instrumentation utilized to perform the procedure . with reference to fig1 - 5 , cannula assembly 200 includes cannula sleeve 202 and cannula housing 204 mounted to an end of the sleeve 202 . any suitable means , known in the art , for mounting cannula sleeve 202 to cannula housing 204 are envisioned including threaded arrangements , bayonet coupling , snap - fit arrangements , adhesives , etc . cannula sleeve 202 and cannula housing 204 may be integrally formed . cannula sleeve 202 defines a longitudinal “ x 1 ” axis extending along the length of sleeve 202 . sleeve 202 further defines an internal longitudinal lumen passage 206 dimensioned to permit passage of surgical instrumentation therethrough . adjacent a distal end of cannula sleeve 202 is formed an aperture 212 which extends through the wall of sleeve 202 and is in fluid communication with lumen 206 of sleeve 202 . aperture 212 permits passage of insufflation gases through cannula sleeve 202 during the surgical procedure . sleeve 202 may be formed of stainless steel or other rigid materials such as a polymeric material or the like . sleeve 202 may be clear or opaque . the diameter of 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 . cannula housing 204 includes port opening 214 ( fig3 ) and luer fitting 216 positioned within the port opening 214 . luer fitting 216 is adapted for connection to a supply of insufflation gaseous is conventional in the art and incorporates valve 218 to selectively open and close the passage of the luer fitting 216 . cannula housing 204 may include and supports a housing insert 210 therewithin . housing insert 210 defines a stem 210 a extending therefrom and configured for insertion or placement within port opening 214 of cannula housing 204 . cannula housing 204 further includes and supports duckbill or zero closure valve 220 configured for positioning within housing insert 210 . closure valve 220 tapers distally and inwardly to a sealed configuration . closure valve 220 defines a slit 222 which opens to permit passage of the surgical instrumentation and closes in the absence of the instrumentation . closure valve 220 is preferably adapted to close upon exposure to the forces exerted by the insufflation gases in the internal cavity . other zero closure valves are also contemplated including single or multiple slit valve arrangements , trumpet valves , flapper valves , etc . closure valve 220 rests upon an internal shelf 210 b of housing insert 210 when assembled . with continued reference to fig1 - 5 , seal assembly 100 will be discussed in detail . seal assembly 100 may be a separate component from cannula assembly 200 and , accordingly , adapted for releasable connection to the cannula assembly 200 . alternatively , seal assembly 100 may be incorporated as part of cannula assembly 200 . seal assembly 100 includes a seal housing or holder 110 , a ball seal 120 , and a seal cover 130 . seal assembly 100 defines central seal axis “ x 2 ” which is preferably parallel to the axis “ x 1 ” of cannula sleeve 202 and , more specifically , coincident with the axis “ x 1 ” of the cannula sleeve 202 . seal housing or holder 110 includes a cylindrical wall portion 112 having a tapered distal portion 114 and a transverse annular wall or flange 116 extending from a proximal end thereof . seal holder 110 defines central passage 118 which is dimensioned to receive a surgical instrument and laterally confine ball seal 120 . as best shown in fig4 and 5 , tapered distal portion 114 is obliquely arranged relative to seal holder axis “ x 2 ” and extends radially inwardly relative thereto in a distal direction . tapered distal portion 114 assists in creating a seal in combination with ball seal 120 , when the instrument is introduced into cannula assembly 200 , as will be discussed in greater detail below . ball seal 120 has a substantially spherical profile and includes a distal aperture 122 and a proximal aperture 124 . distal aperture 122 has a diameter which is relatively smaller than proximal aperture 124 . ball seal 120 has a diameter substantially equal or smaller than a diameter of cylindrical wall portion 112 of seal holder 110 such that ball seal 120 may be seated within central passage 118 of seal holder 110 . distal aperture 122 and proximal aperture 124 may share a common central axis . ball seal 120 may be fabricated from a suitable resilient and / or elastomeric material , such as , for example , natural rubber , polyisoprene . seal cover 130 includes a transverse wall 132 , a cylindrical wall 134 depending in a distal direction from transverse wall 132 and defining a central lumen or passage 136 . seal cover 130 defines a sloped or angled portion 138 between transverse wall 132 and cylindrical wall 134 . cylindrical wall 134 is dimensioned for receipt within proximal aperture 124 of ball seal 120 . cylindrical wall 134 is further dimensioned such that a distal edge thereof terminates at a location proximal of a distal edge of seal holder 110 . sloped portion 138 is obliquely arranged relative to seal housing axis “ x 2 ” and extends radially inwardly relative to the seal holder axis “ x 2 ” in the distal direction . sloped portion 138 assists in guiding the inserted instrument into lumen 206 of cannula assembly 200 , particularly , when the instrument is non - aligned or off - axis relative to the seal holder axis “ x 2 ”, or introduced at an angle relative to the seal holder axis “ x 2 ”. sloped portion 138 provides more flexibility to the surgeon by removing the necessity that the instrument be substantially aligned with the seal holder axis “ x 2 ” upon insertion . seal cover 130 may include an outer wall 139 configured for selective engagement with cannula housing 204 in order to secure seal assembly 100 to cannula assembly 200 . when seal assembly 100 is assembled , ball seal 120 of seal assembly 100 is interposed between seal holder 110 and seal cover 130 . in particular , ball seal 120 is slidably and rotatably interposed between seal holder 110 and seal cover 130 so as to translate in an axial direction and rotate about longitudinal axis “ x 1 , x 2 ”. in use and during insertion into cannula assembly 200 of an instrument having a diameter greater than the diameter of distal aperture 122 of ball seal 120 , as the instrument is inserted into and through central lumen 136 of seal cover 130 , the instrument passes through distal aperture 122 of ball seal 120 . the frictional force or resistance of ball seal 120 along the outer surface of the instrument , as the instrument is advanced into lumen 206 of cannula assembly 200 , causes ball seal 120 to contact or seal against a surface of seal holder 110 , e . g ., against an inner surface of tapered distal portion 114 of seal holder 110 , as seen in fig4 and 5 . further and during withdrawal of the instrument from cannula assembly 200 , the frictional force or resistance of ball seal 120 along the outer surface of the instrument as the instrument is withdrawn from lumen 206 of cannula assembly 200 causes ball seal 120 to contact or seal against a surface of seal cover 130 , e . g ., against an inner surface of transverse wall 132 and / or against a distal edge of cylindrical wall 134 . turning now to fig6 - 8 , a seal assembly , according to an alternate embodiment of the present disclosure , for use with cannula assembly 200 is generally designated as 300 . seal assembly 300 is substantially similar to seal assembly 100 and thus will only be discussed in detail herein to the extent necessary to identify differences in construction and operation thereof . seal assembly 300 includes a seal housing or holder 310 , a ball seal 320 , and a seal cover 330 . seal housing or holder 310 includes a cylindrical outer wall portion 312 a having a tapered distal portion 314 , a cylindrical inner wall portion 312 b extending proximally from a distal end of tapered distal portion 314 , and a transverse annular wall or flange 316 extending from a proximal end thereof . seal holder 310 defines central passage 318 which is dimensioned to receive a surgical instrument and laterally confine ball seal 320 . cylindrical inner wall portion 312 b terminates in a free proximal end or edge . as best shown in fig7 and 8 , tapered distal portion 314 is obliquely arranged relative to seal holder axis “ x 2 ” and extends radially inwardly relative thereto in a distal direction . tapered distal portion 314 assists in creating a seal in combination with ball seal 320 , when the instrument is introduced into cannula assembly 200 , as will be discussed in greater detail below . ball seal 320 has a substantially spherical profile and includes a distal aperture 322 and a proximal aperture 324 . distal aperture 322 has a diameter which is relatively larger than proximal aperture 324 . distal aperture 322 is dimensioned so as to receive cylindrical inner wall portion 318 a of seal holder 310 therewithin . ball seal 320 has a diameter substantially equal to or smaller than a diameter of cylindrical outer wall portion 312 a of seal holder 310 such that ball seal 320 may be seated within a space defined between cylindrical outer wall portion 312 a and cylindrical inner wall portion 312 b of seal holder 310 . distal aperture 322 and proximal aperture 324 of ball seal 320 may share a common central axis . seal cover 330 includes a transverse wall 332 defining a central opening 336 . seal cover 330 may included an outer wall 339 configured for selective engagement with cannula housing 204 in order to secure seal assembly 300 to cannula assembly 200 . when seal assembly 300 is assembled , ball seal 320 of seal assembly 300 is interposed between seal holder 310 and seal cover 330 . in particular , ball seal 320 is slidably and rotatably interposed between seal holder 310 and seal cover 330 so as to translate in an axial direction and rotate about longitudinal axis “ x 1 , x 2 ”. in use and during insertion into cannula assembly 200 of an instrument , having a diameter greater than the diameter of proximal aperture 324 of ball seal 320 , as the instrument is inserted into and through central opening 336 of seal cover 330 , the instrument passes through proximal aperture 324 of ball seal 320 . the frictional force or resistance of ball seal 320 along the outer surface of the instrument , as the instrument is advanced into lumen 206 of cannula assembly 200 , causes ball seal 320 to contact or seal against at least one surface of seal holder 310 , e . g ., against an inner surface of tapered distal portion 314 of seal holder 310 and / or against an inner surface of cylindrical outer wall portion 312 a , as seen in fig7 and 8 . further and during withdrawal of the instrument from cannula assembly 200 , the frictional force or resistance of ball seal 320 along the outer surface of the instrument , as the instrument is withdrawn from lumen 206 of cannula assembly 200 , causes ball seal 320 to contact or seal against a surface of seal cover 330 , e . g ., against an inner surface of transverse wall 332 . turning now to fig9 , a seal assembly , according to an alternate embodiment of the present disclosure , for use with cannula assembly 200 is generally designated as 400 . seal assembly 400 is substantially similar to seal assembly 100 and thus will only be discussed in detail herein to the extent necessary to identify differences in construction and operation thereof . seal assembly 400 includes a seal lower housing 410 , a ball seal 420 , and a seal upper housing 430 . seal lower housing 410 includes a substantially hemispherical recess 411 formed therein . seal lower housing 410 is configured for support on an end of sleeve 202 of cannula assembly 200 , at a location above or proximal of closure valve 220 . ball seal 420 has a substantially spherical profile and includes a distal aperture 422 and a proximal aperture 424 . distal aperture 422 has a diameter which is different than proximal aperture 424 . as seen in fig9 , distal aperture 422 of ball seal 420 may be relatively larger than proximal aperture 424 of ball seal 420 . ball seal 420 defines a hollow cavity , chamber or the like 426 . seal upper housing 430 includes a transverse wall 432 defining a central opening 436 therein that extends into a substantially hemispherical recess 431 . central opening 436 of seal upper housing 430 is in registration with proximal aperture 424 of ball seal 420 . seal upper housing 430 is configured for connection with seal lower housing 410 such that hemispherical recess 431 thereof is in registration with hemispherical recess 411 of seal lower housing 410 . when seal assembly 400 is assembled , ball seal 420 of seal assembly 400 is interposed between seal lower housing 410 and seal upper housing 430 . in particular , ball seal 420 is slidably and rotatably seated within hemispherical recesses 411 and 431 of seal lower housing 410 and seal upper housing 430 so as to translate in an axial direction and rotate about longitudinal axis . in use and during insertion into cannula assembly 200 of an instrument having a diameter greater than the diameter of proximal aperture 424 of ball seal 420 , as the instrument is inserted into and through central aperture 436 of seal upper housing 430 , the instrument passes through proximal aperture 424 of ball seal 420 . the frictional force or resistance of ball seal 420 along the outer surface of the instrument , as the instrument is advanced into lumen 206 of cannula assembly 200 , causes ball seal 420 to contact or seal against at least one surface of seal lower housing 410 , e . g ., against an inner surface of hemispherical recess 411 of seal lower housing 410 . further , during withdrawal of the instrument from cannula assembly 200 , the frictional force or resistance of ball seal 420 along the outer surface of the instrument , as the instrument is withdrawn from lumen 206 of cannula assembly 200 , causes ball seal 420 to contact or seal against a surface of seal upper housing 430 , e . g ., against an inner surface of hemispherical recess 431 of seal upper housing 430 . turning now to fig1 , a ball seal , according to an alternate embodiment of the present disclosure , for use with cannula assembly 200 and with either seal assembly 100 , 200 , is generally designated as 520 . ball seal 520 may have a substantially spherical profile and defines a bore 521 therein . bore 521 defines a central longitudinal axis “ x ” and includes a first aperture 522 . bore 521 terminates at an end wall 523 defining a second aperture 524 therein . first aperture 522 has a diameter “ d 1 ” which is relatively larger than a diameter “ d 2 ” of second aperture 524 . first aperture 522 and second aperture 524 may share a common central axis co - incident with the central longitudinal “ x ” axis . ball seal 520 is configured and dimensioned such that a maximum thickness “ d 3 ” of ball seal 520 , which defines the dimensions of bore 521 , is relatively larger than a thickness “ d 4 ” of end wall 523 . it is contemplated that diameter “ d 1 ” of bore 521 is selected so as to receive cylindrical wall 134 of seal cover 130 ( see fig3 - 5 ) when ball seal 520 is in a first orientation , or to receive cylindrical inner wall portion 312 b of seal holder 310 ( see fig6 - 8 ) when ball seal 520 is in a second orientation . it is further contemplated that diameter “ d 2 ” of end wall 523 is selected to define an instrument seal . ball seal 520 may be fabricated from a suitable resilient and / or elastomeric material , such as , for example , natural rubber , polyisoprene . 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 .
seal assemblies are provided , comprising a seal holder including a cylindrical wall portion having a tapered distal portion , wherein the cylindrical wall portion defines a central passage . the seal assembly comprises a ball seal supported in the central passage of the seal holder . the ball seal includes a distal aperture and a proximal aperture , wherein the distal and / or proximal aperture is dimensioned for substantial sealed reception with a surgical instrument . the ball seal is adapted for angular movement relative to a central longitudinal axis of the seal holder upon angulation of the surgical instrument , whereby the ball seal substantially maintains the seal with the surgical instrument . the seal assembly comprises a seal cover defining an aperture formed in a transverse wall thereof . the seal cover is configured for connection with the seal holder for maintaining the ball seal within the central passage of the seal holder .