Cannula cap including yeildable outer seal and flapper valve

A cannula cap embodiment includes a monolithic elastomeric cap body having a sidewall portion for engaging a proximal end of a cannula, and an end portion connected to the cylindrical sidewall portion. The cannula cap also includes a monolithic flapper valve positioned within an interior of the cap body. The monolithic flapper valve includes a flapper portion, a ringed-shaped flapper mounting portion connected to adjacent interior portions of the cap body, and an integrally formed hinge portion connecting the flapper mounting portion to the flapper portion for permitting the flapper portion to move to an open position when an instrument is positioned within the instrument receiving passageway, and for biasing the flapper portion toward a closed position when an instrument is removed from the instrument receiving passageway. An instrument seal portion of the end portion of the cap body includes a reduced thickness wall portion adjacent an outer opening and extending in a plane transverse to the instrument receiving passageway, and an outwardly extending pleat surrounding the reduced thickness wall portion. The end portion of the cap body also includes a generally planar outer annular portion surrounding the pleat generally aligned with an imaginary plane defined by the reduced thickness wall portion.

FIELD OF THE INVENTION 
The present invention relates to the field of medical devices and, more 
particularly, to a cannula cap for a cannula. 
BACKGROUND OF THE INVENTION 
A cannula or trocar tube is typically used in laparoscopic surgery to be 
inserted into and line an opening made in the body. In other words, a 
cannula provides a portal into a region within the body, such as the 
abdominal region, for example. A surgical trocar is a sharp pointed 
instrument typically initially inserted into a cannula with its pointed 
tip extending outwardly from a distal end of the cannula. The sharp tip 
facilitates penetration of the tissue of the body and positioning of the 
distal end of the cannula into the desired portion of the body. The trocar 
may be removed and a surgical instrument or endoscope may be inserted into 
and manipulated while extending through the cannula. 
To increase visibility and instrument access within the body, a pressurized 
gas is typically introduced into the body to define a surgical cavity into 
which one or more cannulas may extend. Accordingly, the cannula typically 
requires a seal against a loss of pressurized gas both when no instrument 
is positioned within the cannula, and also when an instrument is 
positioned in the cannula. In addition, it may also be desirable to ensure 
a good gas seal with a shaft of the instrument even as the instrument is 
manipulated longitudinally into or out of the cannula, or as the 
instrument is moved in a lateral or side-to-side motion. 
One conventional approach to sealing an instrument passageway through a 
cannula when no instrument is present provides a flapper valve within the 
upper end or cap of the cannula. For example, U.S. Pat. No. 5,104,383 to 
Shichman discloses a flapper valve with a raised center portion for 
effecting sealing with a valve seat defined by a valve mounting portion, 
and with the flapper being pivotally mounted to the surrounding mounting 
portion by a pivot pin. Along these lines, U.S. Pat. No. 5,290,245 to 
Dennis discloses a flapper valve including a domed valve plug, a bias 
spring for biasing the flapper to the closed position, and a hinge pin for 
pivotally connecting the flapper to an adjacent mounting portion. 
U.S. Pat. No. 5,364,372 to Danks et al. discloses a flat flapper valve 
connected via a pivot pin and including a bias spring and associated lever 
arm. U.S. Pat. No. 5,411,483 to Loomas et al. also discloses a 
spring-loaded flapper valve having a flat flap portion. U.S. Pat. No. 
5,385,553 to Hart et al. and U.S. Pat. No. 5,385,560 to Wulf also disclose 
conventional flat flapper valves oriented at an inclined angle and 
pivotally connected to the surrounding cap structure. Unfortunately, 
conventional flapper valves as have been used to seal a cannula require 
several individual parts which are typically independently manufactured 
and which are then assembled, such as by precise alignment and insertion 
of the relatively small hinge pin through the flapper and mounting 
openings to form the flapper valve. 
Relating to the instrument entrance seal of a cannula, elastomeric 
materials have been used in a cannula cap to permit an instrument to pass 
through a suitable opening in the elastomeric material and while forming a 
seal with the instrument. For example, U.S. Pat. No. 5,330,437 to Durman 
discloses an elastomeric self-sealing valve having an undersized outer 
opening. U.S. Pat. No. 5,380,288 to Hart et al. discloses an outer seal 
that permits movement while an inner seal is more rigid to effect complete 
sealing. 
U.S. Pat. No. 5,411,483 to Loomas et al., discussed briefly above, 
discloses various seal embodiments including an annular corrugated portion 
or bellows for facilitating lateral movement of an instrument at the outer 
seal of a cannula cap. Unfortunately, the cannula cap and bellows 
disclosed in the Loomas et al. patent, for example, includes a 
multiplicity of individual component parts requiring assembly. In 
particular, the seal disclosed in the Loomas et al. patent is mounted to a 
ring, in turn, which is captured for lateral movement by a pair of 
opposing walls. 
In addition to mechanical and assembly complexity of many conventional 
cannula caps, the manufacturing costs for such caps can be relatively 
high. Accordingly, the relatively expensive cannula caps are desirably 
sterilized to permit multiple uses. However, in view of small pockets and 
other areas within the caps, sterilization of complicated components may 
also be relatively difficult. 
SUMMARY OF THE INVENTION 
In view of the foregoing background, it is therefore an object of the 
present invention to provide a cannula cap having a reliable and effective 
valve for sealing the instrument receiving passageway of the cannula cap 
and cannula when no instrument is present, and wherein the valve is 
readily manufactured and assembled with any other components of the 
cannula cap. 
It is another object of the invention to provide a cannula cap having an 
outer instrument seal that provides effective sealing for different sized 
instruments, and which permits side-to-side movement of the instrument 
within the cannula and while maintaining an effective gas seal, and 
wherein the cannula cap is readily manufactured. 
It is yet another object of the present invention to provide a cannula cap 
which is readily and inexpensively manufactured to permit disposal after 
one use if desired. 
These and other objects, features and advantages according to the present 
invention are provided by a cannula cap comprising in one embodiment a 
monolithic elastomeric cap body which, in turn, includes a cylindrical 
sidewall portion for engaging a proximal end of the cannula, and an end 
portion connected to the sidewall portion. A monolithic flapper valve is 
preferably positioned within an interior of the cap body. More 
particularly, the end portion of the cap body has a bore therethrough 
defining an instrument receiving passageway. In addition, the monolithic 
flapper valve preferably includes a flapper portion, a flapper mounting 
portion having a ring shaped and being connected to adjacent interior 
portions of the cap body, and an integrally formed hinge portion 
connecting the flapper mounting portion to the flapper portion. 
The hinge portion is for permitting the flapper portion to move to an open 
position when an instrument is positioned within the instrument receiving 
passageway. The hinge portion also biases the flapper portion toward a 
closed position when an instrument is removed from the instrument 
receiving passageway. In other words, the cannula cap may in one 
embodiment be formed of two monolithic component parts --a cap body and a 
flapper valve--to facilitate manufacture, and to be reliable and rugged in 
use. 
The flapper portion of the valve may preferably include a generally planar 
portion and a dome shaped portion connected thereto, and wherein the dome 
shaped portion extends into the instrument receiving passageway to seal 
same when the flapper portion is in the closed position. For consistent 
repeatable sealing, the hinge portion preferably comprises a pair of 
spaced apart straps or living hinges extending between the flapper 
mounting portion and the flapper portion. The straps provide for proper 
sealing of the flapper valve despite any manufacturing or alignment 
tolerances, for example. 
Another aspect of the invention relates to an instrument seal portion of 
the end portion of the cap body. The instrument seal portion preferably 
has an outer opening for receiving the instrument therethrough and forming 
a gas seal therewith. The instrument seal portion preferably comprises 
yieldable sealing means for permitting movement of the instrument in one 
or more of a longitudinal direction into or out of the instrument 
receiving passageway, and a lateral or transverse direction and while 
maintaining an effective gas seal with the instrument. 
The yieldable sealing means may preferably comprise a reduced thickness 
wall portion adjacent the outer opening and extending in a plane 
transverse to the instrument receiving passageway. The yieldable sealing 
means also preferably includes an outwardly extending pleat surrounding 
the reduced thickness wall portion. The end portion of the cap body also 
preferably further comprises a generally planar outer annular portion 
surrounding the pleat and being generally aligned with an imaginary plane 
defined by the reduced thickness wall portion. In addition, the reduced 
thickness wall portion may include a circular reinforcing rib or ridge 
immediately adjacent the outer opening. 
The end portion of the cap body may also comprise a throat portion having a 
distal end defining a valve seat for the flapper portion of the flapper 
valve. The end portion of the cap body may also have an annular recess 
surrounding the throat portion and further defining the valve seat for the 
flapper portion. 
The cap body also preferably has a valve receiving channel extending along 
an interior portion thereof adjacent an interior corner defined at the 
junction between the end portion and the cylindrical sidewall portion. 
Accordingly, the flapper mounting portion is readily positioned and 
secured within the valve receiving channel to thereby securely position 
the flapper valve in its proper position within the cap body. 
The cap body may further include a first series of transverse ribs on an 
interior thereof for removably securing the cannula cap to the proximal 
end of the cannula. Similarly, the cannula cap may also include a second 
series of transverse ribs on an exterior thereof. In one embodiment, the 
flapper valve preferably comprises a plastic material that is flexible, 
but which is still more rigid than the elastomeric material of the cap 
body. The cap body may preferably be formed of an elastomeric material, 
such as silicone rubber. 
A method aspect of the invention is for making a cannula cap for 
positioning on a proximal end of a cannula of a type for receiving an 
instrument therethrough. The method preferably comprises the steps of: 
forming a monolithic elastomeric cap body comprising a sidewall portion 
for engaging a proximal end of a cannula and an end portion connected to 
the sidewall portion, the end portion having a bore therethrough defining 
an instrument receiving passageway; forming a monolithic flapper valve 
comprising a flapper portion, a flapper mounting portion and an integrally 
formed hinge portion connecting the flapper mounting portion to the 
flapper portion; and securing the flapper mounting portion of the 
monolithic flapper valve within the monolithic elastomeric cap body. The 
flapper portion is preferably movable to an open position when an 
instrument is positioned within the instrument receiving passageway and is 
biased toward a closed position when an instrument is removed from the 
instrument receiving passageway. 
The step of forming the monolithic cap body preferably comprises the step 
of molding same from an elastomeric material, such as silicone rubber, for 
example. The step of forming the flapper valve preferably comprises 
molding same from a plastic material more rigid than the elastomeric 
material of the cap body.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The present invention will now be described more fully hereinafter with 
reference to the accompanying drawings, in which preferred embodiments of 
the invention are shown. This invention may, however, be embodied in many 
different forms and should not be construed as limited to the embodiments 
set forth herein. Rather, these embodiments are provided so that this 
disclosure will be thorough and complete, and will fully convey the scope 
of the invention to those skilled in the art. Like numbers refer to like 
elements throughout. 
Referring initially to FIGS. 1-7, the cannula cap 20 in accordance with the 
invention is first described. FIG. 1 illustrates an instrument assembly 15 
including the cannula cap 20 fitted to the upper or proximal end 22a of a 
cannula 22. The cannula 22 also illustratively includes a reduced diameter 
tubular portion 22b which, in turn, includes spirally wound ridges 22c 
thereon, as would be readily understood by those skilled in the art. In 
addition, the cannula 22 may also include a plurality of transverse 
circumferentially extending ribs or ridges 22d on the upper end portion 
22a to secure the cannula cap 20 to the cannula 22. The cannula 22 may be 
used for any of a number of minimally invasive surgical techniques, for 
example, as would be readily understood by those skilled in the art. 
A trocar 23 is shown positioned within the cannula 22 and cannula cap 20. 
The trocar 23 includes an upper handle portion 23a, a shaft portion 23b, 
and a pointed tip 23c as would also be readily understood by those skilled 
in the art. 
The cannula cap 20 in one preferred embodiment of the invention comprises a 
monolithic elastomeric cap body 25 which, in turn, includes a sidewall 
portion 25a for engaging a proximal or adjacent upper end portion 22a of 
the cannula 22. In other embodiments of the invention, the cap body 25 may 
comprise more rigid plastic or other materials as will be readily 
appreciated by those skilled in the art. The cap body 25 also 
illustratively includes an end portion 25b connected to the cylindrical 
sidewall portion 25a. More particularly, the end portion 25b of the cap 
body 25 preferably has a bore 26 therethrough defining an instrument 
receiving passageway. An instrument tip and shaft, such as the illustrated 
trocar tip 23c and shaft 23b may be positioned through the bore 26. 
The spiked end or tip 23c of the trocar 23 extends outwardly from the end 
of the cannula 22 when fully inserted as shown in FIG. 1, to thereby 
facilitate penetration of a portion of the body, such as the abdomen. The 
trocar 23 may be withdrawn and other instruments inserted through the 
cannula cap 20 and cannula 22 for various treatment and diagnostic 
procedures as would be readily understood by those skilled in the art. As 
used herein the term "instrument" is meant to cover not only hand 
manipulable endoscopic instruments, but also endoscopes and other medical 
devices having a shaft portion for extending through the cannula cap 20 
and cannula 22. 
The cap body 25 may further include a first series of transverse ribs or 
ridges 42 (FIG. 5) on an interior thereof to facilitate removably securing 
the cannula cap 20 to the proximal or upper end portion 22a of the cannula 
22. In other words, the interior transverse ribs 42 cooperate with the 
outer ribs 22d on the upper end portion of the cannula to provide a secure 
fit and seal therewith. In addition, the cannula cap 20 may also include a 
second series of exterior transverse ridges or ribs 43 on an exterior 
thereof to facilitate grasping the cannula cap, for example. The exterior 
ribs 43 may also be useful to permit removably securing a reducer, not 
shown, to the outside of the cannula cap 20 as shown, for example, in U.S. 
Pat. No. 5,312,362 to Pfolsgraf et al. The reducer provides a seal with a 
smaller diameter instrument as would be readily understood by those 
skilled in the art. The reducer may take the form of an enlarged cannula 
cap 20, but without the flapper valve 35. Those of skill in the art will 
also readily appreciate other equivalent projections for removably 
securing the cannula cap 20 to the cannula 22, and facilitating grasping 
of the cannula cap 20 or removably securing a reducer to the cap. 
A monolithic flapper valve 35 is preferably positioned within an interior 
of the cap body 25. As will be readily appreciated by those skilled in the 
art the cannula cap 20 may be formed of two monolithic component parts, 
namely the cap body 25 and the flapper valve 35, to thereby facilitate 
manufacturing and to be reliable and rugged in use. The cap body 25 may 
preferably be formed of an elastomeric material, such as silicone rubber. 
The flapper valve 35 preferably comprises a plastic material that is 
flexible yet which is more rigid than the material of the cap body 25. 
The monolithic flapper valve 35 illustratively includes a flapper portion 
35a, a ring shaped flapper mounting portion 35b being connected to 
adjacent interior portions of the cap body 25, and an integrally formed 
hinge portion or pair of hinges 35c connecting the flapper mounting 
portion to the flapper portion. The hinge portion is preferably formed by 
the illustrated pair of spaced apart straps or spaghetti hinges 35c 
extending between the flapper mounting portion 35b and the flapper portion 
35a. Those of skill in the art will recognize that a single hinge or 
multiple hinges are also contemplated by the present invention, although 
benefits are provided by the illustrated pair of spaced apart hinges 35c. 
As will be readily appreciated by those skilled in the art, the hinges 35c 
are for permitting the flapper portion 35a to move or be deflected to an 
open position when an instrument is positioned within the instrument 
receiving passageway or bore 26 as shown perhaps best in FIG. 7. The 
flapper portion 35a of the flapper valve 35 presses lightly against the 
shaft 23b without adversely restricting or effecting the feel of the shaft 
when inserted or manipulated within the cannula 22. The hinges 35c also 
bias the flapper portion 35a toward a closed position when an instrument 
is removed from the instrument receiving passageway (FIG. 5). As would be 
readily understood by those skilled in the art, gas back pressure from 
within the body cavity also serves to fully close the flapper valve 35. A 
gap 35d is preferably defined between the adjacent edges of the flapper 
portion 35a and the flapper mounting portion 35b to provide clearance for 
opening and closing of the flapper portion. 
The flapper portion 35a may preferably include a generally planar portion 
37 and a dome shaped portion 38 connected thereto. The dome shaped portion 
38 may preferably extend into and close off the instrument receiving 
passageway 26 to seal same when the flapper valve 35 is in the closed 
position. The combination of the flapper valve 35 and cap body 25 provides 
for compliance in manufacturing so that the individual components may be 
made to relatively large tolerances, yet which precisely cooperate 
together to define the needed gas tight seals once assembled. In other 
words, the hinges 35c and other components of the flapper valve 35, for 
example, cooperate with the cap body 25 to allow repeated alignment so 
that high tolerance valve seating is achieved by low manufacturing 
tolerance components. The hinges 35c allow the flapper portion 35a to seat 
itself regardless of any mis-shaping of the dome portion 38, for example. 
Turning now additionally to the assembly 30 shown in FIGS. 8 and 9, another 
aspect of the invention relates to an instrument seal portion 40 of the 
end portion 25a of the cap body 25. In FIGS. 8 and 9 the angular 
articulation of the shaft 50 is exaggerated for clarity of explanation as 
will be readily appreciated by those skilled in the art. The instrument 
seal portion 40 preferably has an outer opening 26a for receiving the 
instrument shaft 50 therethrough and forming a gas seal therewith. The 
instrument shaft 50 may be part of any of a number of medical instruments 
or devices as would be readily understood by those skilled in the art. 
The instrument seal portion 40 preferably comprises yieldable sealing means 
for permitting movement of the instrument shaft 50 in at least one of a 
longitudinal direction into or out of the instrument receiving passageway, 
and transverse thereto, and while maintaining an effective gas seal with 
the instrument. In other words, the seal portion 40 tracks movement of the 
instrument without leaking. In addition, the yieldable sealing means 
permits reduced manufacturing tolerances in making the cap body 25 as it 
relates, for example, to alignment with respect to the cannula internal 
bore as will be readily understood by those skilled in the art. 
The yieldable sealing means preferably includes the illustrated reduced 
thickness annular wall portion 41 adjacent the outer opening 26a and 
extending in a plane transverse to the instrument receiving passageway 26. 
The reduced thickness is relative to other parts of the end portion 25b 
and/or to the sidewall portion 25a. 
The yieldable sealing means also preferably includes the illustrated 
outwardly extending pleat 44 surrounding the reduced thickness wall 
portion 41. The pleat 44 may include the inner and outer wall portions 
joined at their upper ends as illustrated. Multiple such pleats 44 are 
also contemplated by the invention as would be readily understood by those 
skilled in the art. The pleat 44 may also include one or more reinforcing 
ribs, not shown, extending in a generally radial direction for additional 
strength. 
The end portion 25b of the cap body 25 also preferably further comprises a 
generally planar outer annular portion 46 surrounding the pleat 44 and 
being generally aligned with an imaginary plane defined by the reduced 
thickness wall portion 41. In addition, the reduced thickness wall portion 
41 may include a circular reinforcing rib 47 immediately adjacent the 
outer opening 26a. As would be readily understood by those skilled in the 
art, the opening 26a is preferably slightly undersized for the instrument 
shaft 50 to be accommodated. The pleat 44, reduced thickness wall portion 
41, the reinforcing rib 47, and throat portion 51 cooperate to permit 
linear shaft movement into and out of the cannula 22, transverse or 
lateral movement, and combinations of such movements as illustrated in 
FIGS. 8 and 9, and while providing a gas tight seal with the instrument 
shaft 50. 
The end portion 25b of the cap body 25 also illustratively includes a 
throat portion 51 having a distal or lower end 51a defining a valve seat 
for the flapper portion 35a of the flapper valve 35. The end portion 25b 
of the cap body 25 also illustratively has an annular recess 53 
surrounding the throat portion 51 and further defining the valve seat for 
the flapper portion 35a of the flapper valve 35. The annular recess 53 
also serves to provide clearance for the hinges 35c (FIG. 5). 
The cap body 25 may also have a valve receiving channel 56 (FIGS. 5 and 7) 
extending along an interior portion thereof adjacent a corner defined by 
the end portion 25b and the cylindrical sidewall portion 25a. Accordingly, 
the flapper mounting portion 35b is readily positioned and secured within 
the valve receiving channel 56 to thereby securely position the flapper 
valve in its proper position within the cap body. An adhesive 58, 
illustrated schematically by the stippling in FIG. 3, may used to 
adhesively secure the flapper valve 35 in position within the cap body 25 
as would be readily appreciated by those skilled in the art. 
A method aspect of the invention is for making a cannula cap 20 for 
positioning on a proximal end of a cannula 22 of a type for receiving an 
instrument therethrough. The method preferably comprises the steps of: 
forming a monolithic elastomeric cap body 25 comprising a sidewall portion 
25a for engaging a proximal end of a cannula 22, and an end portion 25b 
connected to the sidewall portion, the end portion having a bore 26 
therethrough defining an instrument receiving passageway. The method 
preferably further comprises forming a monolithic flapper valve 35, which 
in turn, includes a flapper portion 35a, a flapper mounting portion 35b 
and an integrally formed hinge portion 35c connecting the flapper mounting 
portion to the flapper portion. The method also preferably includes the 
step of mounting the flapper mounting portion 35b within the monolithic 
elastomeric cap body 25. The flapper portion 35a is preferably movable to 
an open position (FIG. 7) when an instrument shaft is positioned within 
the instrument receiving passageway 26 and is biased to a closed position 
(FIG. 5) when an instrument is removed from the instrument receiving 
passageway. 
The step of forming the monolithic cap body 25 preferably comprises the 
step of molding same from silicone rubber. The step of forming the flapper 
valve 35 preferably comprises molding same from a plastic material that is 
flexible to define a workable hinge portion 35C, yet which is more rigid 
than the elastomeric material of the cap body 25. 
Another method aspect of the present invention is for making a medical 
device. The method includes the steps of: providing a cannula 22 
comprising a tube having a distal end and a proximal end; providing a cap 
body 25 comprising an end portion 25b having a bore therethrough defining 
an instrument receiving passageway; and forming a monolithic flapper valve 
35 comprising a flapper portion 35a, a flapper mounting portion 35b, and 
an integrally formed hinge portion 35c. The method further preferably 
comprises the step of securing the monolithic flapper valve 35 and cap 
body 25 to the proximal end of the cannula 22 so that the flapper portion 
35a is moved to an open position when an instrument is positioned within 
the instrument receiving passageway and so that the flapper portion is 
biased toward a closed position when an instrument is removed from the 
instrument receiving passageway. 
The cannula cap 20 according to the invention provides a flapper valve 35 
for reliably and effectively sealing the instrument receiving passageway 
of the cannula cap and cannula when no instrument is positioned within the 
cannula. In addition, the yieldable sealing means, provided in part by the 
reduced thickness wall portion 41 and the pleat 44 of the cap body 25, 
provides effective sealing for an instrument that is positioned within the 
instrument receiving passageway 26, even when the instrument is moved 
longitudinally and/or laterally. Moreover, the operator's "feel" in 
manipulating the instrument is not adversely affected by the yieldable 
sealing means or the flapper valve 35. The yieldable sealing means can 
also readily accommodate different sized instruments. The cap body 25 is 
also readily manufactured and assembled with the flapper valve 35 to form 
the cannula cap 20. 
The cap body 25, as well as the flapper valve 35 may each be readily made 
from low cost materials by low cost manufacturing methods as will be 
readily appreciated by those skilled in the art. In addition, assembly of 
the completed cannula cap 20 is also straightforward and relatively 
inexpensive. Accordingly, one important feature of the cannula cap 20 of 
the present invention is that if desired the cap may be used one time and 
disposed of, so that no sterilization is needed between uses. The cannula 
cap 20 also readily mates with the illustrated cannula 22 which, in turn, 
is relatively simple tubular structure that is easy to sterilize for reuse 
as would also be readily understood by those skilled in the art. 
In other embodiments of the invention, the cannula cap may include an 
integrally formed or monolithic cap body and flapper valve as would be 
readily understood by those skilled in the art. In slightly different 
terms, the cannula cap may include the outer seal portion and while the 
flapper portion may be integrally molded with the cap body. Many other 
modifications and other embodiments of the invention will come to the mind 
of one skilled in the art having the benefit of the teachings presented in 
the foregoing descriptions and the associated drawings. Therefore, it is 
to be understood that the invention is not to be limited to the specific 
embodiments disclosed, and that modifications and embodiments are intended 
to be included within the scope of the appended claims.