Patent Publication Number: US-7585288-B2

Title: Trocar and cannula assembly having conical valve and related methods

Description:
RELATED APPLICATIONS 
     This patent application is a continuation-in-part of, and claims priority to and the benefit of co-pending U.S. patent application Ser. No. 11/153,860 filed Jun. 15, 2005, which is a continuation-in-part of, and claims the benefit of U.S. patent application Ser. No. 10/879,644 filed on Jun. 29, 2004, which was a continuation of, and claimed the benefit of U.S. patent application Ser. No. 10/763,762 filed on Jan. 23, 2004, now abandoned each of which is hereby incorporated by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates in general to the field of medical devices. More particularly, the present invention relates to trocar systems, cannulas, valves, and methods. 
     2. Description of Related Art 
     Trocar systems have been developed over the years for various endoscopic applications in the field of medicine. These trocar systems conventionally include a cannula through which a trocar or obturator or other endoscopic related tool extends. It is known to use one or more valves positioned within or connected to a proximal end of the cannula of a trocar system. Examples of such trocar systems having one or more valves in the cannula thereof can be seen in U.S. Pat. No. 5,226,891 by Bushatz et al. titled “Seal Protection Apparatus,” U.S. Pat. No. 5,308,336 by Hart et al. titled “Seal Protection Mechanism,” U.S. Pat. No. 5,385,553 by Hart et al. titled “Trocar With Floating Septum Seal,” U.S. Pat. No. 5,782,812 by Hart et al. titled “Seal Assembly For Access Device,” U.S. Pat. No. 5,443,452 by Hart et al. titled “Seal Assembly For Access Device,” and U.S. Pat. No. 5,209,737 by Ritchart et al. titled “Lever Actuated Septum Seal.” These devices, however, can be bulky and awkward to use and have complex multi-component mechanical valves which can be difficult and expensive to manufacture and can have an increased risk of mechanical failure. The mechanical valves also have little or no flexibility. 
     Other trocar systems have been developed which are easier to use and have less complex mechanical valves. One example of such trocar system can be seen in U.S. Pat. No. 6,569,119 by Haberland et al. titled “Trocar System Having Cannula with Finger Grips.” These devices provide enhanced gripping and easier handling of the systems. Nevertheless, there is also still a need for alternative cannula and valve configurations for trocar systems, a need for relatively less expensive trocar systems, a need for trocar systems with better performance, a need for more flexible trocar systems and valves which enhance handling thereof by medical personnel users, i.e., physicians, and yet are still effective for various endoscopic surgical procedures. 
     SUMMARY OF THE INVENTION 
     With the foregoing in mind, embodiments of the present invention advantageously provide embodiments of a valve having a unique design to provide a secured seal around a plurality of tools that individually and separately extend through the valve. Embodiments of a valve provide an easier insertion and retraction, of various laparoscopic surgical instruments as well as other surgically related items which have varying diameters. Problematical instruments do not get obstructed or caught in a multi-component valve assembly as disclosed in the prior art. Embodiments of the present invention also advantageously provide a trocar system having relatively low costs associated with the manufacturing of components of the system, e.g., valves, and thereby can reduce the cost associated with the trocar system. Embodiments of the present invention additionally advantageously provide a more flexible trocar system which is effective during various endoscopic surgical procedures. Embodiments of the present invention further advantageously provide enhanced methods of forming a seal around tools and of using a trocar system during surgical procedures. Still further, because embodiments of a valve can have a relatively flat and thin profile and because peripheries of a valve are fixedly connected to a valve housing, the valve advantageously can operate like a membrane. Furthermore, because various types and diameters of tools can be used by medical personnel, embodiments of a valve advantageously allow one type of valve, cannula, or trocar system to be readily used for all of these various sizes and types of tools. 
     More particularly, a trocar system includes, but is not limited to, a cannula having an elongate cannula body. The cannula body has medial and distal portions thereof having at least a first diameter. The cannula body also has a proximal, portion thereof connected to the medial portion and having a second diameter. The second diameter is greater than the first diameter. According to an embodiment of the trocar system, the system also includes a valve housing being readily detachably connected to the proximal portion of the cannula body. The valve housing has an axis and a first opening at a proximal end of the valve housing, a second opening at a distal end of the valve housing, and an axially downward facing shoulder. The first opening is defined by a plurality of sidewalls extending in a substantially axial direction, and has a first opening diameter. 
     According to embodiments of the present invention, the trocar system also includes a cap assembly which includes at least one valve positioned entirely within the valve housing. According to an embodiment of the cap assembly, the at least one valve can include a valve body having an annular-shaped valve opening positioned in a medial portion of the valve body and adapted to individually and separately receive a plurality of different elongate tools. Each of the tools have a different diameter therethrough so that when any one of the plurality of elongate tools is positioned through the valve opening, a septum seal is maintained between peripheries of the valve body surrounding the valve opening and abuttingly contacting outer peripheries of the any one of the plurality of elongate tools extending therethrough. The valve body has first and second layers of a fabric material and a layer of elastomeric material positioned between and contacting each of the first and second layers of the fabric material. The valve body also has a periphery valve section connected to and extending radially outwardly from peripheries of the valve body. The periphery valve section includes an outer ring with an outer perimeter thereof defining an outer perimeter of the septum valve. The outer ring engaging the axially downward facing shoulder of the valve housing. The periphery valve section having a plurality of rib members each radially extending substantially an entire distance between an outer perimeter of the valve body and the outer perimeter of the periphery valve section and symmetrically positioned spaced-apart from each other. The periphery valve section having a greater flexibility than the valve body. The trocar system also includes a compression ring positioned in the valve housing adjacent the septum valve. The compression ring compresses the outer ring of the septum valve against the axially downward facing shoulder of the valve housing in order to fixedly position the septum valve within the valve housing. The compression ring has a compression ring opening substantially aligned axially with the first opening of the valve housing. The trocar system further includes a plurality of tools that each have an elongate body for extending through the valve housing, the valve opening of the at least one valve, and the cannula. 
     Further more particularly, the cap assembly of the trocar system can include, but is not limited to, a valve housing having at least one opening formed in line with an axis of the valve housing, with the at least one opening being defined by a plurality of sidewalls extending in a substantially axial direction. The cap assembly also includes at least one valve positioned adjacent to the at least one opening of the valve housing. The at least one valve includes a valve body having an annular-shaped valve opening adapted to individually and separately receive a plurality of different elongate tools. Each of the elongate tools can have a different diameter so that when any one of the plurality of elongate tools is positioned through the valve opening and abuttingly contacting outer peripheries of the any one of the plurality of elongate tools extending therethrough, a septum seal is maintained between peripheries of the valve body surrounding the valve opening. The valve body has at least one layer of a fabric material and a layer of elastomeric material. The valve body also has a periphery valve section connected to and extending radially outwardly from peripheries of the valve body. The periphery valve section has a plurality of rib members each radially extending substantially an entire distance between an outer perimeter of the valve body and an outer perimeter of the periphery valve section. 
     According to another embodiment of the trocar system, the system can include a valve housing adapted to detachably connect to a cannula and characterized by having a proximal end housing portion, a distal end housing portion, and a medial housing portion connected therebetween having a proximal valve housing inner perimeter surface and a distal valve housing inner perimeter surface which can be of the same or differing diameters. The proximal end housing portion can include a first opening having a first opening diameter defined by portions of an inner valve housing sidewall extending distally in a substantially axial direction. The proximal end housing portion can also include an annular valve ring recess adapted to receive an annular valve ring which surrounds the first opening. The distal end housing portion can include a second opening having a second opening diameter defined by a distal valve housing sidewall extending in a substantially axial direction. 
     According to an another embodiment of the cap assembly, the at least one valve positioned within a valve housing includes a first valve having a valve body which includes a proximal valve section fixedly positioned within the valve housing and a distal valve section extending axially from the proximal valve section and into the proximal portion of the cannula. The proximal valve section can include a valve ring positioned in the valve ring recess of the valve housing. The valve ring has a proximal surface, a distal surface, an inner perimeter surface, and an outer perimeter surface defining an outer perimeter of the valve body. The proximal valve section of the valve body can also include a plurality of convolutes each having a first sidewall extending radially inwardly from a portion of the inner perimeter surface of the valve ring and a second sidewall extending axially from the first sidewall substantially parallel to the inner perimeter surface of the valve ring and forming an inner radial periphery of the proximal valve section. The inner perimeter surface of the valve ring, the first sidewall, and the second sidewall of each of the plurality of convolutes form a respective convolute recess for each of the plurality of convolutes. The proximal valve section of the valve body can also include a plurality of rib members each radially extending substantially an entire distance between the inner radial periphery of the proximal valve section and inner perimeter surface of the valve ring and can be symmetrically positioned spaced-apart from each other. The distal valve section of the valve body can include a valve extension extending axially from the plurality of convolutes. The valve extension can include a proximal end portion substantially connected to a distal portion of each of the plurality of convolutes, a distal end portion, and a substantially conically shaped medial portion connected to and extending therebetween. An annular-shaped valve opening is positioned in the distal end portion of the valve extension and is adapted to individually and separately receive therethrough any one of a plurality of different elongate tools each having a different diameter so that when any one of the plurality of elongate tools is positioned through the valve opening a seal, e.g., septum seal, is maintained between peripheries of the valve extension surrounding the valve opening and outer peripheries of any one of the plurality of elongate tools extending therethrough. 
     The first valve can also include a compression ring positioned in the valve housing abuttingly contacting an axially facing distal surface of the valve ring to hold the valve ring in the valve ring recess and to compress the valve ring against an axially facing inner surface of the proximal end housing portion of the valve housing adjacent the valve ring recess in order to fixedly position the valve within the valve housing. The compression ring can include a compression ring opening substantially aligned axially with the first opening of the valve housing to allow extension of the plurality of elongate tools therethrough, an outer perimeter surface having a radial diameter sized so that the compression ring substantially abuttingly contacts the distal valve housing inner perimeter surface when positioned within the valve housing, and an annular flange extending into each one of the plurality of convolute recesses to individually and separately engage a corresponding one of the plurality of convolutes to further enhance positioning and securing of the first valve within the valve housing. 
     The cap assembly can also include a second valve to advantageously help ensure inter-cavity sealing. The second valve can include an annular flange portion spaced axially from the valve ring of the first valve and having a radial diameter sized so that the annular flange portion substantially abuttingly contacts both the distal valve inner housing perimeter surface and an axially facing distal surface of the compression ring adjacent the compression ring opening to enhance positioning of the second valve at least partially within the valve housing. The second valve can also have a second valve opening positioned within the annular flange portion and substantially aligned axially with the first opening of the valve housing to allow extension of the plurality of elongate tools therethrough, an annular-shaped sidewall connected to the annular flange and extending distally in a substantially axial direction when positioned in the valve housing, and a pair of valve flaps connected to and extending inwardly from the annular-shaped sidewall and having at least one slit along common peripheral edges thereof through which the plurality of tools extend individually and separately. The second valve can be held in place through use of a cap seal ring positioned at least partially within the valve housing and positioned to abuttingly contact a distal surface of the annular flange portion of the second valve when the second valve is positioned in the valve housing. The cap seal ring can have an axially extending annular-shaped flange axially spaced apart from the compression ring to provide a slot or recess to releasably receive the annular flange portion of the second valve. The cap seal ring can also include a plurality of radially extending flanges each adapted to engage outer peripheries of a separate one of the plurality of radially extending flanges of the cannula to slidably detachably connect the valve housing to the cannula. 
     Embodiments of the present invention also include methods of using a trocar system. For example, according to embodiment of a method, the method includes the step of providing a cap assembly in a trocar system. The cap assembly has a septum valve including a valve body having an annular-shaped valve opening positioned in a medial portion of the valve body adapted to receive individually and separately a plurality of tools therethrough so that when any one of the plurality of tools is positioned through the valve opening abuttingly contacting outer peripheries of the any one of the plurality of tools extending therethrough a septum seal is maintained between peripheries of the valve body surrounding the valve opening. The valve body can include first and second layers of a fabric material and a layer of elastomeric material positioned between and contacting each of the first and second layers of the fabric material, and can include a periphery valve section connected to and extending radially outwardly from peripheries of the valve body and having an outer perimeter thereof adapted to be fixedly connected to the valve housing. The periphery valve section can also have a plurality of rib members each radially extending substantially an entire distance between an outer perimeter of the valve body and the outer perimeter of the periphery valve section and symmetrically positioned spaced-apart from each other. The periphery valve section can have a greater flexibility than the valve body. 
     The method of using a trocar system can also include the step of inserting a tool through the septum valve and cap assembly comprising the septum valve thereof. During the inserting step, the periphery valve section is deformed temporarily so that the valve body extends distally by contact pressure from the tool and so that a distal end of the tool is guided toward the valve opening and then the periphery valve section is refracted to its selected biased position upon the complete insertion of the tool. The method of using a trocar system can also include the step of guiding the tool to the septum valve with a substantially cylindrical-shaped cap assembly opening when the tool is being inserted through the cap assembly. The method of using a trocar system can further include the steps of extending the tool through a cannula body matingly connected to the cap assembly at a proximal portion thereof, detaching the cap assembly from the proximal portion of the cannula body, and removing tissue or other specimen from the cannula body. 
     According to another embodiment of the method of using a trocar system, the method can include the step of providing a cap assembly in a trocar system including a valve positioned at least partially within a valve housing. The valve can include a valve body having a proximal valve section positioned within the valve housing and a distal valve section extending axially from the proximal valve section and including a valve extension having a proximal end portion, a distal end portion, and a substantially conically shaped medial portion connected to and extending therebetween. A valve opening is positioned in the distal end portion of the valve extension and is adapted to individually and separately receive therethrough any one of a plurality of different elongate tools. The method can also include the step of inserting a tool through cap assembly including the valve extension and a valve opening thereof, during which the valve extension guides the distal end of the tool to the valve opening and upon reaching the valve opening the valve opening is deformed temporarily by contact pressure from the tool so that upon the complete insertion of the tool a seal is formed around outer peripheries of the tool. The method further includes the steps of guiding the tool to the valve extension with a substantially cylindrical-shaped cap assembly opening when the tool is being inserted through the cap assembly, extending the tool through a cannula body matingly connected to the cap assembly at a proximal portion thereof, detaching the cap assembly from the proximal portion of the cannula body, and removing tissue or other specimen from the cannula body. 
     Embodiments of the present invention also include methods of forming a valve for a trocar system. For example, a method can include providing a slab of an elastomeric material, a first layer of a fabric material overlying the elastomeric material and a second layer of a fabric material underlying the elastomeric material, cutting a disc shape in the slab, compressing the slab so that the elastomeric material extends outwardly from peripheries of the first and second layers of the fabric material, and curing the compressed slab to form a septum valve for a trocar system. 
     Another embodiment of the method of forming a valve for a trocar system can include first inserting a valve having a valve body into the valve housing. A compression ring, for example, coated with an ultraviolet bonding agent, is then placed into the valve housing adjacent and abuttingly contacting the valve in a “stacked” fashion. Following this, the second valve is inserted into the valve housing adjacent and abuttingly contacting the compression ring, and a cap seal ring coated with an ultraviolet bonding agent is placed into the valve housing abuttingly contacting outer peripheries of the second valve. Both the compression ring and cap seal ring can be coated with an ultraviolet bonding agent along the outer peripheries thereof abuttingly contacting the inner peripheries of the valve housing. Once each of the components is in its place, the entire cap assembly is placed in a compression system, wherein each component is compressed to its desired depth into the valve housing. At that point, an ultraviolet light is exposed to the ultraviolet bonding agent to cure the materials. Upon the completion of the curing, the cap assembly is formed as one unit. Beneficially, the second valve can be readily removed and exchanged for a replacement. 
     When constructing a trocar system, the cap assembly is abuttingly and releasably connected to a cannula. The proximal end portion of the cannula body has at least one valve housing mating portion associated therewith and the cap seal ring positioned in the valve housing also has at least one cannula body mating portion or flange associated therewith so that the cap assembly matingly attaches to the cannula body in a secured position and whereby movement of the cap assembly, e.g., rotation, by a hand of a user, releases, e.g., unsecures or unlocks, the respective mating portions for ready removal of the cap assembly by the user with the valve and second valve and so that specimens, e.g., tissue, can be readily removed from the cannula body without damage by the first and second valve. Advantageously, the extraction of large tissue samples and/or gauze packs can be accomplished without removing the cannula from the area where various endoscopic procedures take place. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       So that the manner in which the features and advantages of the invention, as well as others which will become apparent, may be understood in more detail, a more particular description of the invention briefly summarized above may be had by reference to the embodiments thereof which are illustrated in the appended drawings, which form a part of this specification. It is to be noted, however, that the drawings illustrate only various embodiments of the invention and are therefore not to be considered limiting of the invention&#39;s scope as it may include other effective embodiments as well. 
         FIG. 1  is a perspective environmental view of a trocar system positioned within a layer of epidermis of a patient according to an embodiment of the present invention; 
         FIG. 2  is a fragmentary sectional view of a trocar system having first and second valves taken along line  2 - 2  of  FIG. 1  according to an embodiment of the present invention; 
         FIG. 3  is a side elevational view of a trocar system according to an embodiment of the present invention; 
         FIG. 4  is a top plan view of a cap assembly of a trocar system according to an embodiment of the present invention; 
         FIG. 5  is an exploded view of a cap assembly of a trocar system according to an embodiment of the present invention; 
         FIG. 6  is a perspective view of a septum valve of a trocar system according to an embodiment of the present invention; 
         FIG. 7  is a top plan view of a septum valve of a trocar system according to an embodiment of the present invention; 
         FIG. 8  is a bottom plan view of a septum valve of a trocar system according to an embodiment of the present invention; 
         FIG. 9A  is sectional view of a septum valve of a trocar system taken along line  9 A- 9 A of  FIG. 7  according to an embodiment of the present invention; 
         FIG. 9B  is an enlarged fragmentary sectional view of a septum valve of a trocar system according to an embodiment of the present invention; 
         FIG. 10  is a perspective view of an alternate embodiment of a septum valve of a trocar system according to an embodiment of the present invention; 
         FIG. 11  is an enlarged fragmentary sectional view of an alternate embodiment of a septum valve of a trocar system taken along line  11 - 11  of  FIG. 10  according to an embodiment of the present invention; 
         FIG. 12  is a perspective view of an alternate embodiment of a septum valve of a trocar system according to an embodiment of the present invention; 
         FIG. 13  is an enlarged fragmentary sectional view of an alternate embodiment of a septum valve of a trocar system taken along line  13 - 13  of  FIG. 12  according to an embodiment of the present invention; 
         FIG. 14  is a perspective environmental view of a trocar system positioned within a layer of epidermis of a patient according to an embodiment of the present invention; 
         FIG. 15  is a fragmentary sectional view of a trocar system having first and second valves taken along line  15 - 15  of  FIG. 14  according to an embodiment of the present invention; 
         FIG. 16  is a side elevational view of a trocar system according to an embodiment of the present invention; 
         FIG. 17  is a top plan view of a cap assembly of a trocar system according to an embodiment of the present invention; 
         FIG. 18  is an exploded view of a cap assembly of a trocar system according to an embodiment of the present invention; 
         FIG. 19  is a perspective view of a valve of a trocar system according to an embodiment of the present invention; 
         FIG. 20  is a top plan view of a valve of a trocar system according to an embodiment of the present invention 
         FIG. 21  is a bottom plan view of a valve of a trocar system according to an embodiment of the present invention; 
         FIG. 22  is sectional view of a valve of a trocar system taken along line  22 - 22  of  FIG. 21  according to an embodiment of the present invention; and 
         FIG. 23  is an environmental perspective view of a valve, valve mold, and a slab illustrating the formation of a valve according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention will now be described more fully hereinafter with reference to the accompanying drawings, which illustrate embodiments of the invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the illustrated 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, the prime or double prime notation, if used, indicates similar elements in alternative embodiments. 
       FIG. 1  illustrates a trocar system  20 , which advantageously includes a cap assembly  30  having a valve housing  32 . The valve housing  32  advantageously can have a roughened outer surface, e.g., a plurality of dimples  41 , to enhance gripping and rotating thereof by a hand of a user. The trocar system  20  also includes a cannula  40  having an elongate cannula body  42 . The cannula body  42  advantageously includes distal  46  and medial  44  portions thereof having a first diameter and a proximal portion  48  thereof connected to the medial portion  44  and having a second diameter. The second diameter can be advantageously larger or greater than the first diameter as illustrated. The finger gripping means  27  of the trocar system  20 , for example, can be provided by a pair of finger grips  26 ,  28  connected to outer surfaces of the proximal portion  48  of the cannula body  42 . 
     As illustrated in  FIG. 1 , the trocar system  20  further includes a plurality of tools  22 ,  23 ,  24 ,  25  each having an elongate body for extending through the cap assembly  30  and cannula  40 . Advantageously, the plurality of tools  22 ,  23 ,  24 ,  25  each have a different diameter in the range of from about 4 millimeters to about 13 millimeters. The tools can be obturators or other endoscopic related tools for various endoscopic procedures. 
     As perhaps best shown in  FIGS. 1-9B , the cap assembly  30  according to an embodiment of the present invention, can include a valve housing  32  which has a substantially annular shape, a first opening  31  at a proximal end, and a second opening  33  at a distal end. The cap assembly  30  can also include a septum valve  50 . The septum valve  50  is positioned adjacent the first opening  31  of the valve housing  32  and has an outer perimeter thereof fixedly connected to the valve housing  32 . As perhaps best shown in  FIG. 2 , in an embodiment of the present invention, the portion of the cap assembly  30  forming the first opening  31  extends substantially axially downward toward the septum valve  50 . An upper portion of first opening is rounded so as not to have any right angle edges at the first opening  31 , but resulting cross-section is a substantially cylindrical first opening  31  extending along the same axis as that for valve opening  51 . As illustrated in  FIG. 2-3 , the septum valve  50  is positioned entirely within the valve housing  32 . 
     The septum valve  50  advantageously includes a valve body  55 , which has an annular-shaped valve opening  51  positioned in a medial portion of the valve body  55 . The valve opening  51  is adapted to individually and separately receive a plurality of different elongate tools each having a different diameter therethrough. With such design, when any one of the plurality of elongate tools is positioned in the cap assembly  30  through the valve opening  51 , a septum seal is maintained between peripheries of the valve body  55  surrounding the valve opening  51  and abuttingly contacting outer peripheries of the any one of the plurality of elongate tools extending therethrough. Additionally, the valve body  55  advantageously has first  52  and second  53  layers of a fabric material and a layer of elastomeric material  54  positioned between and contacting each of the first  52  and second  53  layers of the fabric material. 
     The septum valve  50  also advantageously includes a periphery valve section  57 . The periphery valve section  57  is connected to and extends radially outwardly from peripheries of the valve body  55 . The periphery valve section  57  has an outer perimeter thereof defining the outer perimeter of the septum valve  50 , which is fixedly connected to the valve housing  32 . Additionally, the periphery valve section  57  has a plurality of rib members  59  radially extending substantially an entire distance between an outer perimeter of the valve body  55  and the outer perimeter of the periphery valve section  57 . Advantageously, the rib members  59  are symmetrically positioned spaced-apart from each other. Still additionally, the periphery valve section  57  further has a plurality of convolutes  58  each positioned between and connected to any two adjacent rib members  59 . The plurality of convolutes  58  are in a selected biased position before and after each of the plurality of different elongate tools extends through the valve opening  51  individually and separately. The plurality of convolutes  58  extend toward the proximal end of the valve housing  32  when in their biased position. 
     As illustrated in  FIG. 2-3 , the cap assembly  30  also includes a second valve  60 . The second valve  60  is advantageously positioned spaced-apart from the septum valve  50  and adjacent the second opening  33  of the valve housing  32 . The second valve  60  advantageously has an annular flange portion  62  for enhancing the positioning of the second valve  60  within the valve housing  32 , annular-shaped sidewalls  64  connected to the annular flange  62  and extending distally when positioned in the valve housing  32 , and at least a pair of valve flaps  66  connected to and extending inwardly from the sidewalls  64  and flange portion  62 . The sidewalls  64 , for example, can extend distally of the end housing so that the flange portion  62  retains only portions of the valve  60  within the end housing  32  and yet slidably or in a spaced-apart relation have other portions which are positioned within the proximal portion  48  of the cannula body  42 . The pair of valve flaps  66  has at least one slit  68  along common peripheral edges thereof through which the plurality of tools extend individually and separately. The second valve  60  also advantageously has ribs or rib members  67 , e.g., formed integrally therewith as a single piece, and connected to the sidewalls  64 , as illustrated, to reduce drag as will be understood by those skilled in the art. The second valve  60  can also be advantageously impregnated with a lubricant such as an oil material to enhance performance of the valve. 
     For the septum valve  50 , the periphery valve section  57  is a continuous extension of the elastomeric layer  54  of the valve body  55 . The periphery valve section  57  as constructed has a greater flexibility than the valve body  55 . The elastomeric material advantageously includes polyisoprene or a fiberous material being impregnated with a silicon material to enhance the strength of the valve  50  and to enhance sliding and sealing of the plurality of tools. The fabric material advantageously includes a family of high-strength and resilient synthetic polymers containing polyurethane. One example of the fabric materials that can be used for constructing the septum valve is Spandex. For Spandex, there are three possible weaves to the fabric, which essentially incorporates Nylon and Lycra in an equally balanced bi-directional weave. The combination of elastomeric and fabric materials provides an enhanced recovery memory and resiliency. As constructed, the septum valve  50  advantageously has a stretching or elastic range to readily accommodate, e.g., auto-reduction, tools or other instruments having a diameter of about 4 millimeters to about 13 millimeters as understood by those skilled in the art while still maintaining pneumoperitoneum. The valve opening  51  of the valve body  55  has a diameter less than the diameter of each of the plurality of tools that extends through the septum valve  50  so that a secured septum seal is provided around outer peripheries of each of the plurality of tools. The second valve  60  advantageously has this range as well, but individually can even have a greater range, e.g., 1 millimeter to 13 or 14 millimeters. Accordingly, with the septum valve  50  and second valve  60  in combination, the trocar system advantageously can receive different diameter instruments without the necessity of switching cannulas or valve systems. 
     The septum valve can advantageously have various embodiments. As illustrated in  FIGS. 6-9B  and  11 - 13 , wiper region, which is the medial region of the valve body surrounding the peripheries of the valve opening and is formed of the elastomeric material, can have different thickness. In one embodiment, the wiper region has a much greater or larger thickness than the adjacent fabric region as illustrated in  FIGS. 6-9B . That is, the fabric layers  52 ,  53  have much greater or larger peripheries adjacent the valve opening  51  than the periphery of the elastomeric layer  54  surrounding the valve opening  51 . In alternative embodiments, the wiper region is getting narrower and the thickness of the wiper is getting closer to the thickness of the adjacent fabric region. 
     Notably, the septum valve  50  is advantageously fixedly secured to the valve housing  32 .  FIG. 5  illustrates a construction process of the cap assembly  30 . To provide secure sealing, the septum valve  50  having the valve body  55  and periphery valve section  57  is first inserted into the valve housing  32  with the convolutes  58  extending towards the proximal end of the valve housing  32 . Then a compression ring  36  coated with an ultraviolet bonding agent is placed into the valve housing  32  adjacent and abuttingly contacting the septum valve  50  in a “stacked” fashion. Following this, the second valve  60  is inserted into the valve housing  32  adjacent and abuttingly contacting the compression ring  36 , and a cap seal ring  38  coated with an ultraviolet bonding agent is placed into the valve housing  32  abuttingly contacting outer peripheries of the second valve  60 . Both the compression ring  36  and cap seal ring  38  are advantageously coated with an ultraviolet bonding agent along the outer peripheries thereof abuttingly contacting the inner peripheries of the valve housing  32 . The compression ring  36  also advantageously extends radially inward axially below the valve body  55  and forms a compression ring opening  37  substantially in-line with the valve opening  51  and the first opening. 
     Once each of the components is in its place, the entire cap assembly is placed in a compression system, wherein each component is compressed to its desired depth into the valve housing. At that point, an ultraviolet light is exposed to the ultraviolet bonding agent to cure the materials. The curing takes place in about 8 seconds. Upon the completion of the curing, the cap assembly  30  is formed as one unit. 
     When constructing a trocar system according to an embodiment of the present invention, the cap assembly  30  is abuttingly connected to the cannula  40 . The proximal end portion  48  of the cannula body  42  has at least one valve housing mating portion  34  associated therewith and the valve housing  32  also has at least one cannula body mating portion  35  associated therewith so that the cap assembly  30  matingly attaches to the cannula body  42  in a secured position and whereby movement of the cap assembly  30 , e.g., rotational, by a hand of a user releases, e.g., unsecures or unlocks, the respective mating portions  34 ,  35  for ready removal of the cap assembly  30  by the user with the septum valve  50  and second valve  60  positioned therein and so that specimens, e.g., tissue, can be readily removed from the cannula body  42  without damage by the septum valve  50  and second valve  60 . The extraction of large tissue samples and/or gauze packs can be accomplished without removing the cannula from the area where various endoscopic procedures take place. 
     The cannula body  42  can be advantageously formed of a clear plastic material so that direct visualization of specimen removal and instrument passage can be advantageously provided. This, for example, allows various types of cutting, gripping, or other types of tools to be inserted through the cannula  40  for various endoscopic procedures. 
     As illustrated in  FIGS. 1-13  and as described above, the present invention also includes embodiments of a method of using a trocar system  20  including the steps of providing a cap assembly  30 , which includes a septum valve  50 ,  50 ′,  50 ″ and inserting a tool  22 ,  23 ,  24 ,  25  through the septum valve  50 ,  50 ′,  50 ″ and cap assembly  30 . During the insertion, the convolutes  58 ,  58 ′,  58 ″ of the periphery valve section  57 ,  57 ′,  57 ″ flex inwardly around the medial portion of the valve body  55 ,  55 ′,  55 ″ and consequently, the periphery valve section  57 ,  57 ′,  57 ″ is deformed temporarily so that the valve body  55 ,  55 ′,  55 ″ extends distally by contact pressure from the tool  22 ,  23 ,  24 ,  25  and so that a distal end of the tool  22 ,  23 ,  24 ,  25  is guided toward the valve opening  51 ,  51 ′,  51 ″. The unique symmetric rib structure of the periphery valve section  57 ,  57 ′,  57 ″ reinforces the movement of the convolutes  58 ,  58 ′,  58 ″ and the recovery of the convolutes  58 ,  58 ′,  58 ″. Because the septum valve  50 ,  50 ′,  50 ″ is constructed in a thin and relatively flat profile, the septum valve  50 ,  50 ′,  50 ″ functions like a thin elastic membrane. The membrane flexes inwardly and outwardly around the medial portion of the valve body  55 ,  55 ′,  55 ″ with the outer peripheries fixedly secured within the valve housing  32  and does not float or rotate in the valve housing  32 . Upon the complete insertion of the tool  22 ,  23 ,  24 ,  25 , the convolutes  58 ,  58 ′,  58 ″ flex outwardly around the medial portion of the valve body  55 ,  55 ′,  55 ″ and consequently, the periphery valve section  57 ,  57 ′,  57 ″ is retracted to its selected biased position. This method also includes extending the tool  22 ,  23 ,  24 ,  25  through a cannula body  42  matingly connected to the cap assembly  30  at a proximal portion  48  thereof, detaching the cap assembly  30  from the cannula body  42  and removing tissue or other specimen as understood by those skilled in the art from the cannula body  42 . 
     Embodiments of the septum valve  50 ,  50 ′,  50 ″ includes a valve body  55 ,  55 ′,  55 ″ having an annular-shaped valve opening  51 ,  51 ′,  51 ″ positioned in a medial portion of the valve body  55 ,  55 ′,  55 ″ and adapted to receive a plurality of tools  22 ,  23 ,  24 ,  25  individually and separately therethrough. The valve body  55 ,  55 ′,  55 ″ advantageously has first  52 ,  52 ′,  52 ″ and second  53 ,  53 ′,  53 ″ layers of a fabric material and a layer of elastomeric material  54 ,  54 ′,  54 ″,  54 ′″ positioned between and contacting each of the first and second layers of the fabric material. The septum valve  50 ,  50 ′,  50 ″ also includes a periphery valve section  57 ,  57 ′,  57 ″ connected to and extending radially outwardly from peripheries of the valve body  55 ,  55 ′,  55 ″ and having an outer perimeter thereof. The periphery valve section  57 ,  57 ′,  57 ″ advantageously has a plurality of rib members  59  each radially extending substantially an entire distance between an outer perimeter of the valve body  55 ,  55 ′,  55 ″ and the outer perimeter of the periphery valve section  57 ,  57 ′,  57 ″ and symmetrically positioned spaced-apart from each other (see  FIGS. 2 ,  6 - 9 B,  11 - 13 ). The periphery valve section  57 ,  57 ′,  57 ″ advantageously has a greater flexibility than the valve body  55 ,  55 ′,  55 ″. 
     Because embodiments of a septum valve  50 ,  50 ′,  50 ″, according to the present invention, have a relatively flat and thin profile and because peripheries of a septum valve  50 ,  50 ′,  50 ″ are fixedly connected to a valve housing  32 , the septum valve  50 ,  50 ′,  50 ″ advantageously can operate like a fixed membrane that flexes distally toward the cannula  40  to allow tools  22 ,  23 ,  24 ,  25  used with the valve  50 ,  50 ′,  50 ″ to be guided toward and readily inserted into the valve opening  51 ,  51 ′,  51 ″. Yet, because tools  22 ,  23 ,  24 ,  25  can be sharp or point on distal ends thereof, the fabric or reinforced layers protect the membrane operation from tears or punctures during insertion of a tool  22 ,  23 ,  24 ,  25 . Further, because various types and diameters of tools can be used by medical personnel, embodiments of a septum valve advantageously allow one type of valve, cannula, or trocar system to be readily used for all of these various sizes and types of tools. 
     As shown in  FIGS. 14-23 , embodiments of the present invention employ a nonplanar valve  150  which can be used with the cannula  40 . Note, for simplicity, components common to both the embodiments described with reference to  FIGS. 1-9B , such as the cannula  40 , and the embodiments that will be described will retain their original numbering. Those components not common will be renumbered accordingly. 
     As perhaps best shown in  FIGS. 14 ,  15 , and  18 , according to an embodiment of the present invention, a cap assembly  130  of a trocar system  120  includes a valve housing  132 . The valve housing  132  which can have, for example, a substantially annular shape, can include a proximal end housing portion  171 , a distal end housing portion  173 , and a medial housing portion  175  connected to and extending therebetween. The proximal end housing portion  171  can include a first opening  131  having a first opening diameter defined by portions of an inner valve housing sidewall  177  extending distally in a substantially axial direction. The inner valve housing sidewall  177  forming the first opening  131  extends substantially axially downward toward a valve opening  151  of a valve  150 , described below. The upper portion of the first opening  131  can be rounded so as not to have any right angle edges at the first opening  131 , but with the resulting cross-section forming a substantially cylindrical first opening  131  extending along the same axis as that for the valve opening  151 . The proximal end housing portion  171  can also include an annular valve ring recess  179  for retaining the valve  150 . The distal end housing portion  173  can include a second opening  133  having a second opening diameter defined by a distal valve housing sidewall  181  extending in a substantially axial direction. The medial housing portion  175  can includes a first proximal valve housing inner perimeter surface  183  and a second distal valve housing inner perimeter surface  185  which can have a perimeter size or circumference the same or slightly larger than that of the first proximal valve housing inner perimeter surface  183 . 
     As perhaps best shown in FIGS.  15  and  18 - 22 , the valve  150  can include a valve body  155  positioned at least partially within the valve housing  132 , axially aligned with the first opening  131  of the valve housing  132 . As perhaps best shown in  FIG. 19 , the valve body includes a proximal valve section  191  fixedly positioned entirely within the valve housing  132  (see  FIG. 15 ) and a distal valve section  193  extending axially from the proximal valve section  191 . The proximal valve section  191  includes a valve ring  195  positioned in the valve ring recess  179  ( FIG. 15 ) of the valve housing  132 . The valve ring  195  has a proximal surface  197 , a distal surface  199 , an inner perimeter surface  201 , and an outer perimeter surface  203  defining an outer perimeter of the valve body  155 . The proximal valve section  191  also can include a plurality of convolutes  158  each having a first sidewall  207  extending radially inwardly from a portion of the inner perimeter surface  201  of the valve ring  195  and a second sidewall  209  extending axially from the first sidewall  207  substantially parallel to or slightly angled from the inner perimeter surface  201  of the valve ring  195  and forming an inner radial periphery of the proximal valve section  191 . The inner perimeter surface  201  of the valve ring  195 , the first sidewall  207 , and the second sidewall  209  of each of the plurality of convolutes  158  form a respective convolute recess  211 . The proximal valve section  191  can also include a plurality of rib members  159  (see, e.g.,  FIGS. 18 and 20 ) each radially extending substantially an entire distance between the inner radial periphery of the proximal valve section  191  and inner perimeter surface  201  of the valve ring  195  and symmetrically positioned spaced-apart from each other. 
     The distal valve section  193  can extend axially from the proximal valve section  191  and can include a valve extension  152  extending axially from the plurality of convolutes  158 . The valve extension  152  can have a proximal end portion  212  substantially connected to a distal portion of each of the plurality of convolutes  158 , a distal end portion  213 , and a medial portion  215  connected to and extending therebetween. According to an embodiment of the valve extension  152 , the medial portion  215  can have a substantially frustro-conical or other similar conical-form shape, as illustrated. The distal valve section  193  includes a valve opening  151  positioned in the distal end portion  213  of the valve extension  152 , which can have, for example, an annular shape. The valve opening  151  is adapted to individually and separately receive therethrough any one of the plurality of different elongate tools  22 ,  23 ,  24 ,  25 , each having a different diameter so that when any one of the plurality of elongate tools is positioned through the valve opening  151  a septum-type seal is maintained between peripheries of the distal end portion  213  of the valve extension  152  surrounding the valve opening  151  and outer peripheries of any one of the plurality of elongate tools when extending therethrough. As noted previously, the plurality of tools  22 ,  23 ,  24 ,  25 , ( FIGS. 1 and 14 ) each have an elongate body for extending through the valve housing  132 , the valve opening  151  of the valve  150 , and the cannula  40 . 
     The plurality of convolutes  158  are each positioned between and connected to any two adjacent rib members  159 . According to an embodiment of the convolutes  158 , each convolute  158  can be in a selected biased position before and after each of the plurality of different elongate tools, individually and separately, extends through the valve opening  151 . According to an embodiment of the present invention, the combination of the convolutes  158  and the valve extension  152  allow for axial movement of the tools  22 ,  23 ,  24 ,  25 , without a corresponding movement within the valve opening  151  with respect to outer peripheries of the tools. 
     The valve body  155 , in general, and the portion of the valve extension  152  surrounding the opening  151 , in particular, can be formed of a flexible material to provide the elastic range necessary to accommodate the plurality of elongate tools  22 ,  23 ,  24 ,  25 . According to an embodiment of the valve body  155 , the flexible material advantageously can include a silicon material coated with paralene, available through various manufacturers including Dow Corning Corp., to enhance the strength of the valve  150  and to enhance sliding and sealing of the plurality of tools  22 ,  23 ,  24 ,  25 . 
     As shown in  FIGS. 15 ,  16 , and  18 , the cap assembly  130  can also include a compression ring  136  positioned in the valve housing  132  at a medially axial position between the first and second openings  131 ,  133 , of the valve housing  132 , abuttingly contacting an axially facing distal surface  199  of the valve ring  195 . The compression ring  136  includes a compression ring opening  137  substantially aligned axially with the first opening  131  of the valve housing  132  to allow extension of the plurality of elongate tools therethrough. The compression ring opening  137  can also be sized to allow at least portions of the inner valve housing sidewall  177  and valve  150  to extend therethrough. The compression ring  136 , also includes an outer perimeter surface  217  having a radial diameter sized so that the compression ring  136  substantially abuttingly contacts the proximal valve housing inner perimeter surface  183  when positioned within the valve housing  132  and includes an annular flange  219  extending into each one of the plurality of convolute recesses  211 . 
     The compression ring  136  is positioned to compress the valve ring  195  against an axially facing inner surface and an axially facing shoulder of the proximal end housing portion  171  of the valve housing  132  which together along with a portion of the first proximal valve housing inner perimeter surface  183  of the medial housing portion  175  form the valve ring recess  179 , and/or to compress the valve ring  195  against the first proximal valve housing inner perimeter surface  183  of the medial housing portion  175 , to hold the valve ring  195  in the valve ring recess  179  to fixedly position the valve  150  within the valve housing  132 . That is, the compression ring  136  is positioned so that the proximal valve housing inner perimeter surface  183 , surfaces forming the valve ring recess  179 , and an annular flange  219  of the compression ring  136  rigidly hold the valve ring  195  within the valve housing  132 . 
     The annular flange  219  of the compression ring  136  can include a plurality of notches  221  symmetrically positioned spaced-apart from each other so that each of the notches  221  aligns with and receives a separate one of the plurality of rib members  159  to thereby rotationally align the compression ring  136  with the valve ring  195  when positioned in contact therewith. Alternatively, the annular flange  219  can include a plurality of separate spaced apart flanges (not shown) having a gap between each pair of flanges defining the notch  221  and aligned with the plurality of remembers  159  to thereby enhance positioning of the valve ring  195 . To further enhance positioning of the valve ring  195 , according to an embodiment of the valve housing  132  and valve ring  195 , the axially facing inner surface of the proximal end housing portion  171  of the valve housing  132  can include one or more protuberances  205  extending at least partially along the length of the valve ring recess  179  and the proximal surface  197  of the valve ring  195  can include one or more recesses  206  or can deform to form a recess  206 , as illustrated, to receive the one or more protuberances  205  to thereby enhance positioning of the valve ring  195  within the valve housing  132 . 
     The cap assembly  130  can also include a second valve  160 . The second valve  160  is advantageously positioned adjacent the second opening  133  of the valve housing  132 , abuttingly contacting the compression ring  139 . The second valve  160  advantageously has an annular flange portion  162  spaced axially from the valve ring of the first valve  150 . The annular flange portion  162  can have a radial diameter sized so that the annular flange portion  162  substantially abuttingly contacts the distal valve inner housing perimeter surface  185  and an axially facing distal surface of the compression ring  136  adjacent the compression ring opening  137  to enhance the positioning of the second valve  160  within the valve housing  132 . The second valve  160  includes a second valve opening  223  positioned within the annular flange portion  162  and, when positioned within the valve housing  132 , is substantially aligned axially with the first and second openings  131 ,  133 , of the valve housing  132  to allow extension of the plurality of elongate tools  22 ,  23 ,  24 ,  25 , therethrough. 
     According to an embodiment of the present invention, annular-shaped sidewalls  164  are connected to the annular flange portion  162  and extend distally in a substantially axial direction when positioned in the valve housing  132 . At least one pair of valve flaps  166  is connected to and extends inwardly from the sidewalls  164  and flange portion  162 . The sidewalls  164 , for example, can extend distally of the end of the valve housing  132  so that the flange portion  162  retains only portions of the valve  160  within the valve housing  132  and yet slidably or in a spaced-apart relation have other portions which are positioned within the proximal portion  48  of the cannula body  42 . Similarly, portions of the valve extension  152  and/or the valve opening  151  of the first valve  150  can extend within the proximal portion  48  of the cannula body  42 . The pair of valve flaps  166  has at least one opening or slit  168  along common peripheral edges thereof through which the tools  22 ,  23 ,  24 ,  25 , can individually and separately extend. The second valve  160  also advantageously can have ribs or rib members (not shown), e.g., formed integrally therewith as a single piece, and connected to the sidewalls  164  to reduce drag as will be understood by those skilled in the art. The second valve  160  can also be advantageously impregnated with a lubricant such as an oil material to enhance performance of the valve. Note, according to an embodiment of the present invention, the illustrated sidewalls  164  can be replaced with other forms of extension extending from the annular flange portion  162  of the second valve  160 . Further, the valve opening  168  can take other forms such as an annular shaped opening or other known to those skilled in the art. 
     The second valve  160 , in general, and the portion of the sidewalls  164  surrounding the opening  168 , in particular, can be formed of a flexible material similar to that used in forming the first valve  150 . For example, according to an embodiment of the second valve  160 , the flexible material advantageously can include a silicon material coated in paralene to enhance the strength of the valve  160  and to enhance sliding and/or sealing of the plurality of tools  22 ,  23 ,  24 ,  25 . 
     According to an embodiment of the cap assembly  130 , in order to enhance positioning of the second valve  160 , a proximal surface of the annular flange portion  162  of the second valve  160  can include an at least partially annular recess  227  or can deform to form a recess  227 , as illustrated, to receive an at least partially annular protuberance  225  extending from a distal surface of the compression ring  136  to thereby enhance positioning of the second valve at least partially within the valve housing  132 . 
     A distal surface of the annular flange portion  162  of the second valve  160  can further include a second valve annular-shaped recess  229  adapted to receive an axially extending annular-shaped flange  272  of the proximal portion  48  of the cannula  40  to thereby enhance positioning of at least part of the proximal portion  48  of the cannula  40  within the valve housing  132 . 
     As shown in  FIGS. 15 ,  16 , and  18 , the cap assembly  130  can also include a cap seal ring  138  positioned at least partially within the valve housing  132  and having an axially extending flange  274  positioned to abuttingly contact a distal surface of the annular flange portion  162  of the second valve  160  when positioned in the valve housing  132 . The cap seal ring  138  can include a plurality of radially extending flanges  135  each adapted to engage outer peripheries of a separate one of the plurality of radially extending flanges  34  of the cannula  40  to slidably detachably connect the valve housing  132  to the cannula  40 . The cannula  40  can also include an annular shaped axially extending flange adapted to engage the annular-shaped recess  229  of the second valve  160  to thereby enhance positioning of the cannula  40  securely against the second valve  160  when positioned in engagement with the radially extending flanges  135  of the cap seal ring  138 . 
     As perhaps best shown in  FIGS. 15 ,  18 , and  23 , embodiments of the present invention a method of forming a trocar system  120 . As constructed, for example, the valve  150  advantageously has a stretching or elastic range to readily accommodate, e.g., auto-reduction, tools or other instruments having a diameter of about 4 millimeters to about 13 millimeters as understood by those skilled in the art while still maintaining pneumoperitoneum. The valve opening  151  of the valve body  155  has a diameter less than the diameter of each of the tools  22 ,  23 ,  24 ,  25 , that extend through the valve  150  so that a secured seal is provided around outer peripheries of each of the tools. The second valve  160  advantageously has this range as well, but individually can even have a greater range, e.g., 1 millimeter to 13 or 14 millimeters. Accordingly, with the valve  150  and second valve  160 , in combination, the trocar system  120  advantageously can receive different diameter instruments without the necessity of switching cannulas or valve systems. 
     The valve  150  is advantageously fixedly secured to the valve housing  132 .  FIG. 23  illustrates an exemplary construction process of the cap assembly  130 . To provide secure sealing, the valve  150  having the valve body  155  is first inserted into the valve housing  132 . Then a compression ring  136 , for example, coated with an ultraviolet bonding agent, is placed into the valve housing  132  adjacent and abuttingly contacting the valve  150  in a “stacked” fashion. Following this, the second valve  160  is inserted into the valve housing  132  adjacent and abuttingly contacting the compression ring  136 , and a cap seal ring  138  coated with an ultraviolet bonding agent is placed into the valve housing  132  and abuttingly contacting outer peripheries of the second valve  160 . Both the compression ring  136  and cap seal ring  138  can be coated with an ultraviolet bonding agent along the outer peripheries thereof abuttingly contacting the inner peripheries of the valve housing  132 . 
     Once each of the components is in its place, the entire cap assembly is placed in a compression system, wherein each component is compressed to its desired depth into the valve housing  132 . At that point, an ultraviolet light is exposed to the ultraviolet bonding agent to cure the materials. The curing takes place in about 8 seconds. Upon the completion of the curing, the cap assembly  130  is formed as one unit. Beneficially, the second valve  160  can be readily removed and exchanged for a replacement. 
     When constructing a trocar system  120 , the cap assembly  130  is then abuttingly connected to the cannula  40 . The proximal end portion  48  of the cannula body  42  has at least one valve housing mating portion  34  associated therewith and the cap seal ring  138  positioned in the valve housing  132  also has at least one cannula body mating portion or flange  135  associated therewith so that the cap assembly  130  matingly attaches to the cannula body  42  in a secured position and whereby movement of the cap assembly  130 , e.g., rotation, by a hand of a user releases, e.g., unsecures or unlocks, the respective mating portions  34 ,  135  for ready removal of the cap assembly  130  by the user with the first and second valves  150 ,  160 , and so that specimens, e.g., tissue, can be readily removed from the cannula body  42  without damage by the first and second valves  150 ,  160 . The extraction of large tissue samples and/or gauze packs can be accomplished without removing the cannula  40  from the area where various endoscopic procedures take place. 
     As illustrated in  FIGS. 14-22 , embodiments of the present invention also include a method of using a trocar system  120  including the steps of providing a cap assembly  130 , which includes a valve  150 , as described above, and inserting a tool  22 ,  23 ,  24 ,  25  through the valve  150  and cap assembly  130 . During the insertion, the convolutes  158  and the valve extension  152  flex so that the valve body  155  extends distally by contact pressure from the tool  22 ,  23 ,  24 ,  25  and so that a distal end of the tool  22 ,  23 ,  24 ,  25  is guided through the valve opening  151 . The unique symmetric rib structure reinforces the movement of the convolutes  158  and the recovery of the convolutes  158  once the tool is extended through the valve opening  151 . Because the valve  150  is constructed in a thin and relatively conical shaped profile, the valve  150  functions like a thin elastic membrane that flexes inwardly and outwardly along a fairly wide range of tool positions without requiring the valve opening  151  to “slide” along the outer peripheries of the respective tool once positioned through the valve opening  151  and does not float or rotate in the valve housing  132 . This method also includes extending the tool  22 ,  23 ,  24 ,  25  through a cannula body  42  matingly connected to the cap assembly  130  at a proximal portion  48  thereof. The method further includes the steps of detaching the cap assembly  130  from the cannula body  42  and removing tissue or other specimen as understood by those skilled in the art from the cannula body  42 . Because various types and diameters of tools can be used by medical personnel, embodiments of a valve advantageously allow one type of valve, cannula, or trocar system to be readily used for all of these various sizes and types of tools. 
     In the drawings and specification, there have been disclosed a typical preferred embodiment of the invention, and although specific terms are employed, the terms are used in descriptive sense only and not for purposes of limitation. The invention has been described in considerable detail with specific reference to these illustrated embodiments. It will be apparent, however, that various modifications and changes can be made within the spirit and scope of the invention as described in the foregoing specification and as defined in the appended claims.