US20050059934A1

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Publication number: US20050059934A1
Application number: US10/830,522
Authority: US
Inventors: Thomas Wenchell; Skott Greenhalgh; David Farascioni
Original assignee: Tyco Healthcare Group LP
Current assignee: Covidien LP
Priority date: 2003-04-25
Filing date: 2004-04-23
Publication date: 2005-03-17
Also published as: AU2010201670B2; EP1615673B1; US20120041271A1; JP2010142655A; WO2004096295A2; US20100222747A1; US8622971B2; AU2004234014A1; AU2004234014B2; EP1615673A2; JP2007525242A; EP1615673A4; CA2522617C; US8070731B2; WO2004096295A3; CA2522617A1; AU2010201670A1; AU2004234014C1

Abstract

An access apparatus for use during a surgical procedure to provide access to the interior of the body includes an access member defining a longitudinal axis and having a proximal end for being disposed at an exterior side of the body and a distal end for extending into the interior of the body. The access member has a bore therethrough dimensioned to permit passage of an object. A seal is disposed within the bore of the access member. The seal includes a fabric material and an elastomeric material, and defines an internal passageway dimensioned to form a substantial sealing relation with an object inserted therethrough.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of priority of U.S. Provisional Application Ser. No. 60/540,421, filed on Jan. 30, 2004 and U.S. Provisional Application Ser. No. 60/466,005, filed on Apr. 25, 2003, the entire contents of which are hereby incorporated by reference.

BACKGROUND

1. Field of the Disclosure

The present disclosure relates to surgical devices and, more particularly, to a surgical access apparatus for use during a minimally invasive surgical procedure. The present disclosure further relates to a novel seal assembly for forming a seal about a surgical object while accommodating angular manipulation of the surgical object.

2. Description of the Related Art

Minimally invasive surgical procedures including both endoscopic and laparoscopic procedures permit surgery to be performed on organs, tissues and vessels far removed from an opening within the tissue. Laparoscopic and endoscopic procedures generally require that any instrumentation inserted into the body be sealed, i.e. provisions must be made to ensure that gases do not enter or exit the body through the incision as, for example, in surgical procedures in which the surgical region is insufflated. These procedures typically employ surgical instruments which are introduced into the body through a cannula. The cannula has a housing at a proximal end thereof in which a seal assembly is mounted. The seal assembly provides a substantially fluid tight seal about the instrument to preserve the integrity of the established pneumoperitoneum. The housing extends above the patient's body, when the cannula is inserted into the incision, reducing the effective length of instruments inserted through the cannula and potentially encumbering maneuverability about the operative site.

Minimally invasive procedures have several advantages over traditional open surgery, including less patient trauma, reduced recovery time, reduced potential for infection, etc. However, despite its recent success and overall acceptance as a preferred surgical technique, minimally invasive surgery, such as laparoscopy, has several disadvantages. In particular, the maintenance of the seal about the surgical instrument within the cannula has proven to be difficult in certain procedures, e.g., in procedures requiring extensive manipulation of the long narrow endoscopic instruments within a remote site. In addition, many conventional seal assemblies are not adapted to accommodate instruments of various sizes, while still maintaining the seal about the inserted instrument. Even further, known seal assemblies are relatively complex, which increases the length of the housing in which it is confined. As a consequence, maneuverability above the operative site and the effective length of the instrument are undesirably affected.

SUMMARY

Accordingly, the present disclosure is directed to an access apparatus for use during a surgical procedure to provide access to the interior of the body. The access apparatus includes an access member defining a longitudinal axis and having a proximal end for being disposed at an exterior side of the body and a distal end for extending into the interior of the body. The access member has a bore therethrough dimensioned to permit passage of an object. A seal is disposed within the bore of the access member. The seal includes a fabric material and an elastomeric material, and defines an internal passageway dimensioned to form a substantial sealing relation with an object inserted therethrough.

Preferably, the fabric material comprises a braided fabric material, and is generally elongated extending along the longitudinal axis of the access member. The braided fabric material may be a tubular braided fabric material.

The seal may include an outer surface with the elastomeric material being at least partially disposed at the outer surface. The outer surface is substantially impervious to passage of insufflation gases. The seal includes an inner surface with the braided fabric material being at least partially disposed at the inner surface for engagement with the instrument. The seal may be substantially impervious to passage of insufflation gases along a substantial length of the seal. Alternatively, the seal may include a porous section adjacent one end thereof to permit passage of insufflation gases.

The seal may be mounted within the access member to define an outer passageway between the seal and the access member. The seal may be secured to the access member at a first location along the longitudinal axis and may be secured to the access member at a second location along the longitudinal axis distal of the first location. The access member may include a channel extending distal of the first location for introduction of insufflation gases into the outer passageway. The porous section of the seal is adjacent the second location to permit passage of insufflation gases between the internal passageway of the seal and the outer passageway.

In one embodiment, the seal includes a constricted area which is expansible to engage the object in substantial fluid tight relation therewith. The elastomeric material is impregnated into the braided fabric material of the seal.

In another embodiment, the seal includes first and second ends. The first end of the seal is secured to the access member at a first location along the longitudinal axis. The second end of the seal is adapted for axial movement in response to passage of an object into the internal passageway of the seal. Preferably, the seal includes a seal mount which is adapted for longitudinal axial movement with the second end of the seal being secured to the seal mount.

In another embodiment, a cannula assembly for use in a surgical procedure is disclosed. The cannula assembly includes a cannula member defining a longitudinal axis and having a longitudinal bore therethrough for passage of a surgical instrument, a cannula housing defining an opening for receipt of the instrument with the cannula housing being connected to a proximal end of the cannula member so that the opening and the bore communicate with one another, and a sealing member mounted within the cannula member for forming a substantial seal with the instrument. The sealing member includes a fabric material which includes a plurality of strands and an elastomeric material.

The fabric material has an elongate shape extending along the longitudinal axis and a predetermined shape prior to insertion of the instrument. The fabric material has a proximal end, a distal end, and a sloped portion therebetween. The sloped portion defines a passageway for the receipt of the instrument and is arranged to form a substantial seal therewith. The fabric material comprises an expansible fabric and is arranged to expand upon engaging the instrument. The elastomeric material is disposed adjacent at least a center-portion of the sealing member. The center-portion is adapted to expand in receiving the instrument.

The fabric material may have a tubular shape and may be braided. The fabric material may include a plurality of monofilament strands and a plurality of multifilament strands.

The sealing member includes an outer surface with the elastomeric material being at least partially disposed at the outer surface. The outer surface is substantially impervious to passage of insufflation gases. The sealing member includes an inner surface with the fabric material being at least partially disposed at the inner surface, for engagement with the instrument. The elastomeric material may be impregnated into the fabric material of the sealing member.

The sealing member may include first and second ends with the first end being secured to the cannula member at a first location along the longitudinal axis. The second end is adapted for axial movement in response to the passage of an instrument through the sealing member. The cannula assembly may further include a seal mount adapted for longitudinal axial movement, whereby the second end of the sealing member is secured to the seal mount.

In another preferred embodiment, a surgical access apparatus for providing access to the interior of the body, includes an access member defining a longitudinal axis and having a proximal end for being disposed at an exterior side of the body and a distal end for extending into the interior of the body and a longitudinal passage extending therethrough, and an elongated seal coaxially mounted within the passage of the access member to define an outer passageway between the access member and the elongated seal. The seal includes a fabric material and an elastomeric material, and has a longitudinal passageway for receipt of an object therethrough in substantial sealed relation therewith. At least one of the access member and the elongated seal defines a port to permit communication of insufflation gases between the outer passageway and the longitudinal passage of the seal. The access member may include an insufflation port to permit passage of insufflation gases from an external source to the outer passageway, and may define a channel in communication with the insufflation port and the outer passageway.

The elongated seal includes an elastomeric material which is substantially impermeable to passage of insufflation gases. The elongated seal may have a distal end portion devoid of the elastomeric material to permit passage of insufflation gases through the fabric material between the outer passageway and the longitudinal passage of the seal.

The elongated seal may include an expansible fabric which is arranged to expand upon engaging the instrument. The sealing member may have a constricted shape for engaging the instrument at an area around a center of the elongated seal. The elongated seal may include an elastomeric material at at least the center. The elongated seal may be secured to an inner surface of the access member at a first location along the longitudinal axis. The elongated seal may be secured to an inner surface of the access member at a second location disposed distally of the first location, so as to form the outer passageway between the elongated seal and the access member. The port is defined in the access member and disposed distally of the first location to allow the release of insufflation gases from the outer passageway.

The elongated seal may define a tubular shape. The elongated seal has a constricted shape defining the interior passageway of the elongated seal and being arranged so that upon insertion of the instrument through the interior passageway, the instrument expands the interior passageway forming a substantial seal therewith.

The access apparatus may also include a zero-closure seal mounted relative to the cannula member and adapted to close in the absence of the instrument.

In another alternative embodiment, the surgical access apparatus includes an access member defining a longitudinal axis and proximal and distal ends, and having a passageway therethrough dimensioned to permit passage of an object, and an elongated seal disposed within the passageway of the access member. The elongated seal includes a proximal end secured within the access member and a distal end mounted for axial movement within the access member. The distal end is moveable to a retracted position to permit the passageway of the elongated seal to expand to accommodate the object in substantial fluid tight relation therewith. Preferably, the elongated seal comprises a fabric and may be a tubular braided fabric. A seal mount may be attached to the distal end of the elongated seal and movable between extended and retracted positions.

In another preferred embodiment, a fabric material for a seal is disclosed. The fabric material includes a tubular braid of a plurality of strands having a polymeric material. Preferably, the tubular braid has between about 48 and about 196 strands which are selected from a group consisting of a plurality of monofilament strands having a diameter of between about 0.001 and about 0.007 inch, and a plurality of multifilament strands having a denier of between about 75 and about 300. The polymeric material is selected from the group consisting of polypropylene, nylon, Teflon, polyethylene terepthalate (“PET”) and polyarylether-ether ketone (“PEEK”).

In another preferred embodiment, a seal including an elastomeric material and a fabric material is disclosed. The fabric material comprises a tubular braid of a plurality of strands. The strands include a polymeric material. The tubular braid has between about 48 and about 196 strands selected from a group consisting of a plurality of monofilament strands having a diameter of between about 0.001 and about 0.007 inch, and a plurality of multifilament strands having a denier of between about 75 and about 300. Preferably, the seal has a drag force of between about 0 and about 10 pounds and a leak rate of between about 0 and about 270 cc/min. The elastomeric material may have a durometer of between about 10 and about 80 shore A, an elastomeric material thickness of between about 0.003 and about 0.015 inches, and a cover factor of between about 0 and about 1. The seal has a density of strands to free space of between about 10% and about 70%, a constricted area having a length of between about 0.1 and about 2.0 inches, a braid angle of between about 0 and about 90 degrees, an initial seal diameter of between about 3 and about 10 mm, and a maximum seal diameter of between about 5 and about 18 mm. The elastomeric material may be selected from the group consisting of polyurethane, polyisoprene, silicone, Monprene™, Santoprene™ and other thermoplastic elastomers (TPE). The seal preferably has a diameter between about 4 mm and about 15 mm. The seal may have a minimum diameter and a maximum diameter, whereby maximum diameter is between about 3 times and about 5 times greater than the minimum diameter.

A method of gaining access to a surgical site within a body is also disclosed.

BRIEF DESCRIPTION OF THE DRAWING(S)

Preferred embodiments of the present disclosure will be better appreciated by reference to the drawings wherein:

FIG. 1 is a perspective view of an access apparatus in accordance with an embodiment of the present disclosure;

FIG. 2 is a second perspective view with cut-away portions showing the interior of the cannula of the access apparatus in accordance with the embodiment ofFIG. 1;

FIG. 3 is a side cross-sectional view of the access apparatus in accordance with the embodiment ofFIGS. 1 and 2;

FIG. 4A is an enlarged cross-sectional view with portions removed of the access apparatus in accordance with the embodiments ofFIGS. 1-3;

FIG. 4B is an enlarged cross-sectioned view illustrating the components of the connection of the seal within the cannula in accordance with the embodiment ofFIGS. 1-4A;

FIG. 5 is a side plan view of the seal assembly of the access apparatus in accordance with the embodiment ofFIGS. 1-4B;

FIG. 6 is an enlarged isolated view in cross-section ofFIG. 5, detailing the components of the seal of the access apparatus in accordance with the embodiment ofFIGS. 1-5;

FIG. 7 is a chart illustrating a preferred range of various design parameters for forming the seal of the access apparatus in accordance with the embodiment ofFIGS. 1-6;

FIG. 8 is a schematic side plan view of a mandrel used in a preferred process for forming the seal in accordance with the embodiment ofFIGS. 1-6;

FIG. 9 is a schematic top plan view of a mold used in a preferred process for forming the seal in accordance with the embodiment ofFIGS. 1-6;

FIGS. 10-11 are cross-sectional views of an access apparatus in accordance with a further embodiment of the disclosure;

FIG. 12 is a side cross-sectional view of an access apparatus in accordance with another embodiment of the disclosure;

FIG. 13 is a side plan view of a seal assembly of an access apparatus in accordance with the embodiment ofFIG. 12;

FIG. 14 is an enlarged isolated view in cross-section of the constricted area of the seal assembly in accordance with the embodiment ofFIGS. 12 and 13;

FIG. 15 is a side cross-sectional view of another embodiment of an access apparatus of the present disclosure; and

FIG. 16 is a side plan view of the access member of the access apparatus in accordance with the embodiment ofFIG. 15.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

The access apparatus of the present disclosure provides a substantial seal between a body cavity of a patient and the outside atmosphere during insertion of an object through the apparatus. Moreover, the access apparatus of the present disclosure is capable of accommodating objects of varying diameters, e.g., instruments from about 4.5 mm to about 15 mm or more, and provide a gas tight seal with each instrument when inserted. This flexibility of the access apparatus greatly facilitates endoscopic surgery where a variety of instruments having differing diameters are often needed during a single surgical procedure.

The apparatus incorporates a seal assembly which permits the introduction and manipulation of various types of instrumentation adapted for insertion through a trocar and/or cannula assembly while maintaining a substantial fluid tight interface about the instrumentation to preserve the atmospheric integrity of a surgical procedure from gas and/or fluid leakage. Specifically, the seal assembly accommodates angular manipulation of the surgical instrument relative to the seal axis in addition to off-axis manipulation of the surgical instrument. This feature of the present disclosure desirably minimizes the entry and exit of gases and/or fluids to/from the body cavity. Examples of instrumentation include clip appliers, graspers, dissectors, retractors, staplers, laser probes, photographic devices, endoscopes and laparoscopes, tubes, and the like. Such instruments will be collectively referred to herein as “instruments or instrumentation”.

The access apparatus may also be adapted to receive and form a seal about a physician's arm or hand during a hand-assisted laparoscopic procedure.

Referring now to the drawings, in which like reference numerals identify identical or substantially similar parts throughout the several views,FIGS. 1-6 illustrate an access apparatus in accordance with an embodiment of the present disclosure. For exemplative purposes, the access apparatus will be described in terms of a cannula assembly which is adapted for introduction, typically utilizing a trocar, within the abdominal cavity during a laparoscopic surgical procedure. However, it is appreciated that the access apparatus may be any apparatus suitable for introduction and passage of surgical objects into underlying tissue including, e.g., catheters, trocar assemblies, endoscopic portals, hand access devices, etc., through an incision or through a natural body opening.

With reference toFIGS. 3, 4A and4B, in conjunction withFIGS. 1-2,cannula assembly100 will now be described.Cannula assembly100 includes a generally tubular member, similar to the conventional cannulas suitable for the intended purpose of accessing a body cavity and permit introduction of instruments therethrough.Cannula assembly100 is particularly adapted for use in laparoscopic surgery where the peritoneal cavity is insufflated with a suitable gas, e.g., CO₂, to raise the cavity wall from the internal organs therein.Cannula assembly100 is typically used with an obturator assembly, such as a sharp tipped trocar, which is an elongate instrument positionable within thecannula assembly100. InFIG. 2, anobturator1000 is shown partially introduced withincannula assembly100. Theobturator assembly1000 may have a sharp end, a blunt end, or a tapered end for separating or dilating tissue, and is utilized to pass through, e.g, abdominal tissue, to facilitate introduction of thecannula assembly100 within the abdominal cavity. Once access to the abdominal cavity is achieved, theobturator assembly1000 is removed from thecannula assembly100 to permit introduction of the surgical instrumentation utilized to perform the procedure.

In one preferred embodiment, access apparatus, i.e.,cannula assembly100, includescannula sleeve102 having proximal and

distal ends

101,103 andcannula housing104 mounted to theproximal end101 of thesleeve102.Cannula sleeve102 defines a longitudinal axis “a” extending along the length ofsleeve102.Sleeve102 further defines an internallongitudinal passage106 dimensioned to permit passage of surgical instrumentation.Sleeve102 incorporatessleeve flange108 monolithically-formed (FIG. 3) at theproximal end101.Sleeve102 may be fabricated of stainless steel or another suitable rigid material such as a polymeric material or the like.Sleeve102 may be clear or opaque. The diameter ofsleeve102 may vary, but, typically ranges from 5 to 15 mm.Sleeve flange108 has aseal support202 integrally formed with or attached to thesleeve flange108.Sleeve Flange108 further includes at least one circumferential recess or slot110 within its outer surface.Circumferential slot110 mates or cooperates with corresponding structure ofcannula housing104 to securecannula sleeve102 andcannula housing104.

As best depicted inFIGS. 3, 4A and4B,cannula housing104 is connected tosleeve flange108 ofcannula sleeve102. In one preferred embodiment, the connection is achieved through ultrasonic welding, adhesives, cements, etc. In the alternative, thecannula housing104 andsleeve flange108 may be connected through a bayonet, threaded or snap-fit coupling, e.g., incorporating adetent116 ofcannula housing104 which is received withinslot110 ofsleeve flange108. An O-ring118 is desirably disposed between aninterior bearing surface120 ofcannula housing104 and anexterior bearing surface122 ofsleeve flange108 to minimize leakage of gases between thecannula housing104 andsleeve flange108 during use in the laparoscopic procedure.

Avalve support114 is mounted betweencannula housing104 andsleeve flange108.Valve support114 includesinner column124 andouter collar126 coaxially disposed about theinner column124.Valve support114 has adistal end113 and aproximal end115.Outer collar126 is mounted against the internal surface ofsleeve flange108 and may be secured thereto with the use of adhesives, cements, etc. The O-ring118 is captured between a dependingleg127 ofouter collar126,cannula housing104 andsleeve flange108, as best seen inFIG. 4A. Aresilient valve128 is supported withinvalve support114.Resilient valve128 includes acircumferential ledge130 which is engaged by theproximal end115 ofinner column124 and secured against an interiorplanar surface132 ofmain housing104 so thatresilient valve128 is supported within the interior of theinner column124.Valve128 may be of general duck-bill configuration and defines aninterior slit134 which opens to permit passage of an object and closes in the absence of the object. Thevalve128 is desirably a zero closure valve or a slit seal which is adapted to close in the absence of a surgical object to thereby prevent passage of insufflation gases throughcannula assembly100. In the alternative,valve128 may be a flat disc-shaped valve, balloon valve, flapper valve, conical valve, etc. In one preferred embodiment,valve128 is the fabric seal disclosed in commonly assigned U.S. patent application Ser. No. 10/165,133, filed Jun. 6, 2002, the entire contents of which are incorporated herein by reference. The seal disclosed in the '133 application may be a flat septum seal having a first layer of resilient material and a second fabric layer juxtaposed relative to the first layer. In yet a further alternative,valve128 is preferably a fabric seal and is desirably arranged so as to have a constricted area. The fabric is desirably constructed of a material that forms a constriction or closure. The seal may also be molded with a resilient material so as to have a constriction. Other arrangements forvalve128 are also envisioned.

Cannula housing

104 desirably includesport136, as best seen inFIG. 2, for connecting a stop cock to thecannula housing104. The stop cock connects to an external source of insufflation gases for introducing insufflation gases into the body cavity of the patient throughcannula sleeve102.Port136 is in communication withchannel138 defined adjacent the interior ofsleeve flange108 of cannula sleeve102 (FIGS. 3, 4A and4B).Channel138 opens tolongitudinal passage106 ofcannula sleeve102.

Referring now toFIGS. 3-6, in conjunction withFIGS. 1-2,seal assembly200 ofcannula assembly100 will be discussed in detail.Seal assembly200 includeselongated seal204 which extends from, theseal support202. As best depicted inFIGS. 4A and 4B,seal support202 is a generally annular element having aninternal opening205 and anouter trough206 defined between inner and outer upwardly extending

walls

208,210 of the seal support202 (FIG. 4B). Thedistal end113 ofvalve support114 is shaped to be received inouter trough206. The proximal end ofelongated seal204 is captured betweenouter trough206 and thedistal end113 of thevalve support114 to mount theseal204 as will be discussed. Alternatively or additionally, theseal204 may be glued or adhered to theseal support202 and/orsleeve flange108.Seal support202 is disposed within the internal boundary ofsleeve flange108 ofcannula sleeve102 when in the assembled condition of the apparatus. Theseal support202 may comprise a separate part attached to thecannula sleeve102 orsleeve flange108, or a part formed integrally with thesleeve flange108 orcannula sleeve102. In either case, theseal support202 is desirably arranged so as to permit flow of insufflation gases throughchannel138.

Elongated seal

204 comprises an elastomeric material, a fabric material, and/or combinations of these materials. The fabric material may comprise braided, woven, knitted, non-woven materials. In a preferred embodiment, as best seen inFIGS. 5-6,elongated seal204 incorporates a tubularbraided fabric material212. The tubular braided fabric may comprise strands of polyethylene, polypropylene, polyethylene, nylon, polyamides, polyglycolic acid, polyethylene teraphthalate (PET), glycolide-lactide copolymer, poly aryl ether-ether ketone, etc. and/or a combination of these strands. Metal strands, such as stainless steel, MP35N, nitinol and/or Titanium may also be used to form the fabric material. As used herein, the term “strands”, “yarns” or ends include both monofilaments and multifilaments.

Variations of the tubular braid are envisioned. The tubular braid may include a variety of braid types with the number of strands (also called “ends of yarn” or “ends”), braid angle, strand diameter, and denier selected in accordance with desired characteristics of the fabric material. The tubular braided fabric material for the seal desirably has strands comprising a polymeric material, and having between about 48 and about 196 strands. The strands are desirably a plurality of monofilament strands having a diameter of between about 0.001 and about 0.007 inch, and a plurality of multifilament strands having a denier of between about 75 and about 300.

Preferred alternative examples of braided fabric materials are listed herein below:

- 1) 144 braided strands, with 72 of the strands comprising 0.003″ PET (polyethylene terephthalate) monofilament and 72 of the strands comprising 100 denier PET multifilament.
- 2) 144 braided strands with 72 of the strands comprising 0.005″ PET monofilament and 72 of the strands comprising 100 denier PET multifilament.
- 3) 144 braided strands of 0.003″ PET or PEEK monofilament.

In the embodiment shown inFIGS. 1-6, theelongated seal204 comprises a composite structure incorporating thetubular braid212 and anelastomeric material214. The elastomer is mounted to, formed on, or otherwise applied to the exterior surface of the braid, and preferably extends approximately the entire length of the tubular braid. The processes contemplated for applying the elastomer include spraying, dipping, injection molding, compression molding and extrusion processes including coextrusion, pulltrusion, corrugating as with vacuum or pressure etc. Preferably, the elastomer is formed so that the elastomer impregnates the fabric of the tubular braid, while leaving at least a portion of the fabric strands exposed at an interior surface of thebraid212. Theelastomeric material214 may comprise polyurethane, polyisoprene, or any suitable elastomer or resilient material. Other suitable elastomeric materials include polyurethane, silicone, polyisoprene, momprene, sanoprene, thermoplastic elastomers (“TPE”), material rubbers and any suitable materials.

In one preferred embodiment of theelongated seal204, the fabric material comprises a tubular braid having 144 strands of 0.003″ PEEK molded with polyisoprene. The polyisoprene alone has a coefficient of friction of about 0.9, whereas the composite structure had a coefficient friction of about 0.16.

With reference again toFIGS. 3-6, the configuration of one preferred embodiment ofelongated seal204 is depicted.Elongated seal204 defines seal axis “b” which is coincident with axis “a” ofcannula assembly100.Elongated seal204 incorporatestubular braid212, which extends the length of theseal204, andelastomeric material214 mounted to, formed on, or otherwise applied to thetubular braid212.Elongated seal204 further includescannula tip216 secured to the distal end of theelongated seal204. In a preferred embodiment,cannula tip216 is directly secured toelongated seal204 with an adhesive or formed during a molding process. Desirably, theelongated seal204 is mounted in thecannula sleeve102 with a degree of slack in the longitudinal direction. Upon insertion of an instrument though theelongated seal204, and expansion of thetubular braid212 in a radial direction, thetubular braid212 contracts in a longitudinal direction. Mounting theelongated seal204 with slack facilitates expansion of theelongated seal204 without undue strain on theelongated seal204.

Elongated seal

204 defines a slightly curved or circular arcuate profile sloping inwardly from its proximal end to acenter220 and then sloping outwardly from thecenter220 to its distal end. This sloped, constricted configuration is created during manufacturing of the tubular braid and elastomer assembly. Thetubular braid212 and/orelastomeric material214 may be formed in the curved shape and then joined to one another. Alternatively, the curved shape may be formed in the process of joining a constant diameter tubular braid and elastomer.

In the embodiment shown inFIGS. 1-6, theseal204 has a circular concave shape, i.e., a curve having one radius. In other embodiments, curves having more than one radius may be used. The geometry and shape ofelongated seal204 affects sealing, snagging and push through force. Generally, shorter seal lengths decrease the chance of snagging and provide lower insertion forces. The shape ofelongated seal204 should balance sufficient sealing with push through forces.Elongated seal204 is arranged so that an area of the seal around thecenter220 is positioned to engage the instrument. The shape ofelongated seal204 and position of engagement with the instrument will define the approach angle of the tip of the instrument, relative to theseal204. An approach angle approaching zero degrees, i.e., tangent to the surface of the seal, decreases snagging and push through force. A longer, gradually tapering, circular concave, or hyperabolic configuration is preferred, as such a shape creates a lower approach angle and lessens snagging and push through force. The fabric material, or elastomeric material, or both, are desirably pre-formed into the constricted or hourglass shape. Preferably,seal204 includes an elongated shape that braid212 assumes naturally, under tension, as this facilitates the manufacturing process.

The novel arrangement of theelongated seal204 has many benefits. Theelongated seal204 seals around an instrument inserted into thepassage106. Theseal204 is disposed within thepassage106 of thecannula sleeve102, and not within thecannula housing104, so that thecannula housing104 has a lower profile. The lower profile ofcannula housing104 effectively extends the useful length of the instrument which is inserted into thecannula assembly100.

Furthermore, it is desirable to minimize the drag of the seal on the instrument so as to facilitate the manipulation of the instrument through thecannula assembly100. Theseal204 desirably comprises a fabric material, arranged to ease insertion of the instrument. Preferably, the fabric material engages the instrument upon insertion. In embodiments incorporating elastomeric and fabric composite materials, the elastomeric material is preferably at least partially impregnated into the fabric material so that theseal204 is largely elastomeric material at an outer surface thereof and possesses largely fabric strands at an inner surface thereof. Theseal204 may be entirely elastomeric material at an outer surface thereof and mostly fabric strands at an inner surface thereof. The fabric strands engage the instrument upon insertion, minimizing contact with the elastomeric material. Contact with the elastomeric material tends to increase the friction forces with the instrument. However, it is contemplated that elastomeric material may be formed on the inner surface ofelongated seal204. In certain embodiments, lubricants, coatings and/or other materials may be used to reduce friction.

The composite structure of certain preferred embodiments also reduces the tendency of the instrument to snag the fabric strands, even where the fabric strands are exposed at an inner surface of theseal204. Without committing to any particular theory of operation, it is believed that the elastomeric material holds the strands in place, reducing the tendency of the instrument to catch the strands.

The elongate tubular shape of theseal204 in certain preferred embodiments engages the instrument along the longitudinal axis “b” of theseal204, increasing the contact area with the instrument, and improving sealing. The fabric material provides sufficient resiliency to seal with instruments in a range of sizes. The fabric material may be arranged to provide good sealing characteristics in the absence of any elastomeric material. The elastomeric material of certain preferred embodiments further provides sealing and resiliency for theseal204.

Elongated seal

204 defines aninternal passageway222, within thepassage106 of thecannula sleeve102, which opens to the underlying body cavity to permit passage of an instrument. When the instrument is inserted, the fabric material and elastomeric material expands to enable the instrument to pass while establishing a sealed relation with the object. In the absence of an instrument, theseal204 returns to its normal constricted configuration under the influence of the resiliency ofelastomer204 and fabric material.

Elongated seal

204 is coaxially arranged withincannula sleeve102 to define anouter passageway224 between theelongated seal204 and the internal surface ofcannula sleeve102. Theouter passageway224 communicates withchannel138 andport136.Elongated seal204 further defines a gap226 (FIG. 4) or portionadjacent cannula tip216 devoid of the elastomer. Thegap226 permits the passage of insufflation gases betweenouter passageway224 andinternal passageway222 ofelongated seal204. Insufflation gases are introduced fromport136, throughchannel138 throughouter passageway224, outgap226 into the body cavity, to expand the body cavity. Alternatively or additionally,gap226 permits the insufflation gases to pass fromouter passageway224 tointernal passageway222, as well as frominternal passageway222 intoouter passageway224, to substantially equalize the pressure within the two locations to allow the seal to adjust to instruments of different sizes. Thegap226 may be provided during the molding process or, alternatively, may be the result of a removal step where the elastomer is removed subsequent to molding to define thegap226. Thegap226 may be created by perforating or forming a slit in the outerelastomeric material214. It is further envisioned thatcannula sleeve102 may include an opening in its outer wall in communication with theouter passageway224 to permit passage of gases to the abdominal cavity. This feature will be discussed in detail herein below.

The insufflation pressure may enhance the sealing ability ofelongated seal204, by allowing the insufflation gases to pass intoouter passageway224 betweenelongated seal204 andcannula sleeve102. If this feature is utilized, thin-walled fabrics and lower Durometer elastomeric materials, are preferred. As an alternative togap226, one or more slits may be formed inelongated seal204 and arranged to open only when exposed to a predetermined pressure, to allow seal inflation. As another alternative,elongated seal204 is devoid of an opening or openings wherebyouter passageway224 is inflated so as to constrictinternal passageway222 ofelongated seal204 and form a seal about an inserted instrument. In the alternative, insufflation gases may be introduced betweenseal204 and thecannula sleeve102 without inflating the seal by providing gas release structure e.g., through thegap226, or in the form of an opening in the wall ofcannula sleeve102.

The access apparatus includes, in certain preferred embodiments, a fixation device at a distal end of the cannula sleeve. The fixation device desirably comprises the anchor disclosed in certain embodiments of U.S. Pat. No. 5,232,451, or the anchor disclosed in certain embodiments of U.S. Provisional Application No. 60/512,389, filed Oct. 17, 2003, the disclosures of which are both hereby incorporated by reference herein. In the alternative, a balloon anchor according to certain embodiments of U.S. Pat. No. 5,697,946 or 5,468,248 may be used, the disclosures of which are both hereby incorporated by reference herein.

The access apparatus according to the present disclosure may incorporate further features such as a skin seal or anchor, such as disclosed in certain embodiments of International Application No. WO 02/096307, the disclosure of which is hereby incorporated by reference herein. The access apparatus may be used with a radially expandable sleeve, as disclosed in certain embodiments of U.S. Pat. Nos. 5,431,676 and 5,183,464, the disclosures of which are both hereby incorporated by reference herein. In further embodiments, the cannula sleeve may include threads on an exterior surface thereof. As disclosed in certain embodiments of U.S. Pat. No. 6,224,608, the disclosure of which is hereby incorporated by reference herein, or a texture on an outer surface thereof. The cannula housing may define loops, flanges, or other structures for use as suture anchors. A person of ordinary skill will appreciate that all these features are well within the present disclosure.

In one preferred process of manufacture, tubularbraided fabric material212 includes a plurality of monofilament and multifilament polyethylene terephthalate (PET) fibers which are braided with, e.g., a braiding machine, to define a general tubular shape. Braiders for forming the tubular braided fabric material are commercially available. For example, Steeger machines from Steeger may be used (Korting Nachf. Wilhelm Steeger in Germany). Preferably, the tubular braid is formed in a tubular shape which defines a diameter approximating the maximum diameter of theelongated seal204 during use. Thereafter, the tubularbraided fabric material212 is placed on a mandrel or pin, so that the mandrel or pin extends through the interior of thetubular braid212. The mandrel has a shape which generally conforms to theinternal passageway222 ofelongated seal204 in its final state as depicted inFIG. 5, i.e., the shape of the mandrel generally corresponds to a desired end result of thetubular braid212 depicted inFIG. 5.FIG. 8 depicts asuitable mandrel300 to form the desired hourglass shape. Thetubular braid212 is placed under tension to conform the braid to the shape of the mandrel. Thereafter, the shaped or slopedtubular braid212 is subjected to a molding process to apply anelastomeric material214 onto at least an exterior surface of thetubular braid212. The preferred molding process is effectuated through, e.g., an injection molding process or a compression molding process.FIG. 9 illustrates a lower half of amold400 utilized to apply the elastomeric material. Themold400 defines amold cavity402 corresponding to the general configuration of the tubular braid212 (shown in phantom) to receive thebraid212 preferably with themandrel300. Themold400 provides aslight clearance404 about the periphery of thecavity402 to receive the elastomeric material. The upper half of themold400 would be identical to the lower half depicted inFIG. 9.

With one preferred injection molding process, the shaped or slopedtubular braid212 and mandrel are positioned within an injection mold having a shape generally corresponding to the shapedtubular braid212 as discussed hereinabove. A molten elastomer is injected into the mold around thetubular braid212. Upon curing, theelastomer coating214 bonds to the exterior surface of thebraid212. As appreciated, the molten elastomer may migrate into the interstices of thebraid212 to fully impregnate thebraid212. However, the preferred process prevents complete communication of the molten elastomer to the interior surface oftubular braid212. This is desirably accomplished by applying sufficient tension to thetubular braid212 so as to increase contact with the mandrel, decreasing thebraid212 diameter, which increases the density of the braid, minimizing migration of elastomer to the inner surface of thetubular braid212. At least a portion of the strands of the tubular braid are exposed at the inner surface of thetubular braid212. A lubricious coating may be applied to the inner surface of thetubular braid212, to further reduce insertion forces. Lubricious coatings including hydrogels and medical fluid may be used. Preferred materials for injection molding include thermoplastic elastomers (“TPE”). Any suitable elastomer may be used.

Alternatively, a compression molding process may be utilized to form theelastomeric material214. In accordance with one preferred process, thetubular braid212 andmandrel300 are placed within a compression mold (such asmold400 ofFIG. 9) having a mold cavity conforming to the desired shape for thetubular braid212. Heat and pressure are applied so that the molten elastomer is then compressed within thetubular braid212 to cover at least the exterior surface of thetubular braid212 and impregnate interstices of the braided fabric material. Pressure may be applied using mechanical pressure and/or a vacuum. Preferably, complete communication of the molten elastomer to the interior surface oftubular braid212 is avoided, as well-the benefits of which are discussed hereinabove. Any suitable elastomer may be used. One preferred elastomer for compression molding is polyisoprene.

It is envisioned that during either the injection or compression molding processes,cannula tip216 may be positioned within the molds and secured to thetubular braid212 through an overmolding step. It is also envisioned that thecannula tip216 be formed using injection molding as the elastomer is injected, or serially before or after the elastomer is injected, over thebraid212. In addition, thecavity402 of themold400 may include spaces for the elastomeric material to build up, forming elastomeric features on theseal assembly200. Thetubular braid212 desirably extends beyond the end of the mold, for clamping and/or tensioning thetubular braid212.

Referring again toFIGS. 3-6, the proximal end ofelongated seal204 has acircumferential flange218.Flange218 is monolithically formed from theelastomeric material214 during, e.g., the injection or compression molding processes.Circumferential flange218 is received withintrough206 ofseal support202 and may be secured within thetrough206 with the use of adhesive, cements or the like. As discussed hereinabove, thedistal end113 ofinner column124 ofvalve support114 securescircumferential flange218 withinseal support202 by engaging theflange218 to secure it within thetrough206 along with the proximal end of thefabric material212.

In yet another preferred method, thetubular braid212 may be dipped into a pool of elastomeric material. A preferred elastomer is urethane. The urethane wicks to the interior surface of thetubular braid212 to form a urethane layer at the inner surface of thetubular braid212. Thetubular braid212 is then inverted such that the elastomeric material is largely disposed on the exterior of thetubular braid212. Thetubular braid212 is placed under tension to form a constricted shape along its length to shape the braid, and heat is applied to the assembly. The assembly is cured under the tensioned stated to define desired curved configuration of theelongated seal204.

Alternatively, in accordance with another process, an elastomer jacket may be separately formed in the desired sloped or tapered configuration and then adhered or otherwise bonded to the outer surface of thetubular braid212 to impart the desired tapered configuration totubular braid212.

In another embodiment, thetubular braid212 may include either monofilament fibers or a combination of monofilament and multifilament fibers, which are wrapped with strands such as elastomeric strands.

Irregardless of the above described processes employed,elastomeric material214 serves as a further barrier to the insufflation gases.Elastomeric material214 also provides further resiliency of theelongated seal204. The braid expands in receiving instruments, forming a fluid tight seal about the instrument, and the braid returns to its initial constricted arrangement subsequent to removal of the instrument. Theelastomeric material214 also expands in receiving the instrument and returns to an initial constricted arrangement upon removal of the instrument.

It is further contemplated that an elastomeric material may be applied to cover the inner surface oftubular braid212 in addition to theelastomeric material214 at outer surface of thebraid212. Preferably, the inner layer has a relatively high durometer to minimize resistance to the inserted instrument, whereas the outer layer preferably has a relatively lower durometer. The inner layer may incorporate protrusions to fill any gaps betweenelongated seal204 and the inserted instruments. The inner and outer elastomeric materials may be formed using injection molding, extrusion or co-extrusion processes, injection coining and compression molding.

As discussed hereinabove,tubular fabric212 may also be formed by a weaving process. The fabric is initially woven into a tube-like structure with the “ends” running in the longitudinal axis of the seal, and the “fill” running in the opposite direction. The fill strands, at least in the center of the seal, comprise LYCRA (trademark of I.U. DuPont and Nemours Company) strands. The LYCRA strands form the constricted shape for the seal. The LYCRA serves to facilitate the establishment of a seal about the instrument and controls puckering of the fabric, which may lead to leakage. Various materials are contemplated for the weave including 80 denier PET, 20 denier PET, etc. with all or less than the entire fill comprising LYCRA. It is further contemplated that several strands of PTFE or polypropylene may be intermingled amongst the various other longitudinally-running ends to reduce friction and facilitate passage of the instrument through the woven seal. PTFE and polypropylene by their respective natures have a low-friction characteristic. Desirably, the seal includes a woven fabric material and an elastomeric material. The woven fabric may further include pleats defined in the interior of the tubular fabric. The pleats may tend to eliminate gaps and other avenues betweenelongated seal204 and the surgical instrument.

Other arrangements and methods of manufacture forelongated seal204 are also envisioned. Some exemplative arrangements and processes of manufacture directed to the fabric material are discussed below:

Braid Examples:

1. Spool wind 72 spools of 0.003″ polyester (PET) monofilament clear with no lubricant on a winding apparatus such as a Fletcher spool winder. The winding apparatus should be tensioned appropriately. Spool up 72 ends of a 100 denier PET with no lubricant/sizing, with 100 Denier, 36 end with high interlacing, PET, for a total of 144 ends. Next load up both sets of 72 spools on a 144 carrier machine with low tension spring systems. The spools are loaded in a pattern to create a fabric having alternating ends of monofilament and multifilament. The braid is manufactured without a mandrel at a pick count of 28 picks per inch. “Picks per inch” is defined herein as the number of intersections between ends, per inch of fabric. This creates a tube of 144 ends at approximately 3-4 mm in diameter with a cover factor of 70%. This tube is then impregnated with a polymer in order to create a composite seal structure using any of the methods discussed above. The composite tube has the ability to stretch radially 400-500%. The length of the braided tube shortens by 15-20 when stretched to 500% the original diameter.
2. Spool wind 72 spools of 0.003″ Teflon (PTFE) monofilament clear with no lubricant. Spool up 72 ends of a 100 denier PET with no lubricant/sizing and 100 Denier, 36 ends with high interlacing, PET for a total of 144 ends. Next load up both sets of 72 spools on a 144 carrier machine with low tension spring systems. The spools are loaded in a pattern to create a fabric having alternating ends of monofilament and multifilament. The braid is manufactured without a mandrel at a pick count of 28 picks per inch. This creates a tube of 144 ends at approximately 3-4 mm in diameter with a cover factor of 70%. This tube is then impregnated with a polymer in order to create a composite seal structure (using any of the methods discussed above). The composite tube has the ability to stretch radially 400-500%. The length of the braided tube shortens by 15-20 when stretched to 500% the original diameter. The PTFE monofilaments create a low drag inner surface to the seal to reduce push through force.
3. Spool wind 144 spools of 0.003″ polyester (PET) monofilament clear with no lubricant. Next load up both sets of 144 spools on a 144 carrier machine with low tension spring systems. The braid is manufactured without a mandrel at a pick count of 29 picks per inch. This creates a tube of 144 ends at approximately 3-4 mm in diameter with a cover factor of 60%. This tube is then impregnated with a polymer in order to create a composite seal structure (using any of the methods discussed above). The composite tube has the ability to stretch radially 400-500%. The length of the braided tube shortens by 15-20 when stretched to 500% the original diameter. The 100% monofilament braid has higher abrasion resistance and is less prone to snagging due to the increased stiffness the monofilaments add to the fabric.
Weave Examples:
1. A narrow fabric loom is set up with 200 denier PTFE filaments in the warp direction at a warp density of 50 ends per inch. The loom is configured to weave a continuous tube. Spandex fill yams of 40 denier are woven into the fabric at a constant fill density of 150 picks per inch. By manipulating the fill yam tension, the fabric tube “power” or squeeze force may be selectively adjusted.
2. A narrow fabric loom is set up with 200 denier PTFE filaments in the warp direction at a warp density of 50 ends per inch. The loom is configured to weave a continuous tube. Spandex fill yams of 80 denier are woven into the fabric at a constant fill density of 60 picks per inch. The fill yam tension may be manipulated to change the fabric tube “power” or squeeze force.
3. A narrow fabric loom is set up with 200 denier PTFE filaments in the warp direction at a warp density of 50 ends per inch. The loom is configured to weave a continuous tube. Spandex fill yams of 40 denier are woven into the fabric at a variable fill density of 50 to 150 picks per inch. The fill yam density may be manipulated to change the fabric tube “power” or squeeze force over given controlled fabric lengths.
4. A narrow fabric loom is set up with 200 denier PTFE filaments in the warp direction at a warp density of 50 ends per inch. The loom is configured to weave a continuous tube. Spandex fill yarns of 40 denier are woven into the fabric at a constant fill density of 150 picks per inch. The diameter of the tube may be adjusted by changing the warp density. The larger less dense fabric can become smaller in diameter which in turn reduces the fill yarn tension and reduces power.
Knit Examples:
1. A one inch head circular knitting machine from Lamb Knitting Corporation with 36 needles per inch was set up to knit a tube using a 200 Denier polyester yarn. The higher the needle density, the more dense the fabric. Denser fabric tends to resist poke through and snagging. Knit fabrics are physically more flexible than braids or weaves. The knit structure is a stretchy reinforcing material able to conform to the seals shape and stretch open when required to pass tools through the tube.
2. A one inch head Lamb circular knitting machine with 36 needles per inch was set up to knit a tube using a 200 Denier Teflon yarn. The higher the needle density, the more dense the fabric. Denser fabric tends to resist poke through and snagging. Teflon reduced tool push through drag.
3. A double needle bar warp knitting machine was set up to knit a tube. The warp knitter has 28 needles per bar and PET 200D yarn. Higher needle densities create a denser tube fabric. The warp knit structure is a stretchy reinforcing material able to conform to the seals shape and stretch open when required to pass tools through the tube. Warp knits are highly durable. A seam is created when warp knitting a tube.

In use of the apparatus, in laparoscopic surgery, for example, the underlying body cavity, e.g., the abdominal cavity is insufflated, as is known, to expand the body cavity and displace the abdominal wall from the underlying organs therein.Cannula assembly100, withobturator1000 positioned therein, is advanced within the abdominal tissue to penetrate the abdominal wall.Obturator1000 is removed whilecannula assembly100 remains within the incision. Surgical instruments are advanced withincannula assembly100, openingvalve128, and enteringinternal passageway222 ofelongated seal204. The instruments are advanced whereby theelongated seal204 engages the instrument and expands outwardly to form a fluid tight seal about the exterior surface of the instrument. The instrument is utilized to perform the desired procedure. The configuration ofelongated seal204 permits the seal to move relative to axis “a”, as the instrument is manipulated during the surgery. As discussed below in connection withFIGS. 10 and 11, the area ofseal204 that engages the instrument is greater for an instrument with a larger diameter, as compared to an instrument with a smaller diameter. During the procedure, insufflation gases are introduced throughouter passageway224. The gases pass throughgap226 ofelongated seal204 to enter the body cavity to maintain insufflation of the body cavity. The insufflation gases also pass throughgap226 fromouter passageway224 tointernal passageway222 and frominternal passageway212 toouter passageway224 ofelongated seal204 to substantially equalize pressure between theouter passageway224 andinternal passageway222 ofelongated seal204 as instruments are inserted and removed.

The present disclosure contemplates changes to the structure of the seal. For example, the fabric material of the elongated seal may comprise any suitable fabric structure. The fabric material ofelongated seal204 must have adequate snag resistance, adequate sealing, and generate acceptable push-through forces upon insertion and removal of an instrument. Fabric materials have certain characteristics that affect the snag resistance, sealing and push through forces, including the material modulus, size and type of strands (also known as yarns), density, power, and geometry of the fabric structure.

As discussed in greater detail hereinbelow,elongated seal204 is arranged in a constricted shape, e.g., a circular concave, a hyperbolic, or an hourglass shape, so that a portion of the seal engages an instrument upon insertion of the instrument into the seal. The fabric structure is desirably selected so that the strands largely extend in the longitudinal axis of theelongated seal204, to reduce snagging. The fabric structure should be selected with a tortuous fluid path, as these fabric materials have lower permeability and greater sealing around the instrument.

The fabric is desirably formed from a plurality of polymeric strands which conform to the instrument inserted without pocketing. The strands for the fabric can be metal, such as stainless steel, MP25N, nitinol and/or Titanium. Pocketing is the formation of an indentation in the fabric when engaged by an instrument and tends to result in greater snagging of the fabric by the instrument. Materials with a lower modulus of elasticity are desirable for their greater sealing characteristics, whereas higher modulus materials are desirable for their lower push through forces and lower snagging. The strands of the fabric desirably has a modulus greater than or equal to 700,000 PSI, for acceptable pocketing and snagging. The smaller the size of the strands that form the fabric, the greater sealing and lower push through forces achieved. However, multifilament strands over 100 Denier and monofilament strands greater than 0.003 inches in diameter are desired, for acceptable snag resistance.

Fabrics which are denser and have higher cover are desired. Tighter or more dense fabrics have lower permeability (defined by cc/cm{circumflex over ( )}2/min). Denser fabrics create a more durable, better sealing structure, with less snagging. Denser, tighter fabrics, having smaller pores, resist snagging, whereas more open fabrics allow instruments to “poke through” the pores and snag. Denser fabrics are formed from a greater number of strands. Fabric materials with greater density produce lower push through forces, as the instrument tends to slide on the strand surfaces. This is surprising, as normally greater friction results from greater surface contact.

Preferably, the density of the fabric, when an instrument is inserted and the seal is expanded to its greatest size is more than 48 strands per inch (also known as “ends per inch”), but not more than 200 strands. The number of ends per inch is measured around the fabric perimeter. If the number of ends per square inch is too high, the constricted shape or hourglass shape can not be formed without puckering, which tends to cause leaking. To increase the density of the fabric, while improving the ability of the fabric to form a constricted shape or hourglass shape, a greater number of smaller yams may be used. However, multifilament strands over 100 Denier and monofilament strands greater than 0.003 inches in diameter are desired, for acceptable snag resistance.

The fabric desirably has enough “power” to create an effective seal without increasing the push through forces and snagging to an unacceptable level. “Power” defines the level of “squeezing force” the seal applies to an instrument inserted into the seal. If the power level of the fabric is high, the seal squeezes the instrument with more force. Higher power improves sealing around the instrument.

The fabric material may comprise strands of multifilament, monofilament, or a combination of multifilament and monofilament strands. The permeability of the fabric material, as defined by cc/cm{circumflex over ( )}2/min, is lower for multifilament fabrics than monofilaments. Multifilament strands create a high resistance to fluids and greater sealing, whereas monofilaments create a low resistance to fluids and leak more. Monofilaments have a greater resistance to snagging as compared to multifilaments.

Runners can be used on the fabric structure (e.g., knits, weaves, braids), extending in the axial direction of the seal, down the length of the seal. Runners greatly improve snag resistance. The runners desirably comprise higher modulus monofilaments of, for example, polypropylene, PEEK, polyester, nylon or other suitable materials. The runners also add radial stiffness to the fabric structures. This stiffness reduces pocketing and snagging. Runners increase the strand surfaces which are engaged by the instrument and in turn reduce push through forces.

The elongated seal is preferably formed from a composite structure of fabric material and a resilient material, preferably comprising an elastomeric material. The elastomeric material may comprise any suitable material. The elastomeric material is used to cover and shape a “zone” of the seal. Theelastomeric material214 and fabric of thetubular braid212 form a composite structure. The sum of the components, i.e., fabric material and the elastomeric material, define the final seal geometry, create the power for sealing, and have significant effects on the push through force and snag resistance. The elastomeric material facilitates holding the tubular fabric structure together, diminishing the chance of snagging.

Elastomeric materials with higher Durometer (a measure of hardness), above 70 shore-A, tend to produce better seals. Creep is lowered and tacky surface properties diminish as Durometer increases. Higher Durometer elastomeric materials produce seals with higher power, and better sealing. Thicker films of elastomeric material also produce more power for the seal. However, these characteristics must be balanced against greater push through forces.

It is desired that the surfaces of the strands oftubular braid212 are available or presented at the inner surface ofelongated seal204, to contact the instrument to reduce the push through forces. The harder, higher modulus polymers used to make the strands tend to be quite lubricious, reducing friction, as compared to elastomeric material.

The elastomeric material must substantially fill the “gaps” in the fabric material in order to create a film or membrane throughout the entire fabric surface. A complete film will assure that fluid does not pass through the seal. A seal with a thinner wall is desirable because such a seal leaves less space for fluid to escape.

The composite seal structure should be flexible and conformable enough to move with the instrument, which improves sealing and reduces the chance of pocketing and snagging. These characteristics are governed by fabric construction, strand type, elastomeric material type, and seal geometry. Thus, the fabric construction, strand type, elastomeric material type, and seal geometry should be selected to form a seal with the desired sealing and snagging. Thinner more compliant fabric and elastomeric material composite structures also decrease push through forces.

FIG. 7 is a design chart illustrating a three dimensional envelope for a preferred seal composite structure. In all cases, the X, Y, and Z axis variables are adjusted, compensated and interchanged to create a design volume (dv) for optimum seal design. Anything outside of the dv may still produce a working seal, however, with less attractive working features such as higher push through forces, less snag resistance, more leakage, or the other characteristics discussed above. The optimum features for the seal (quantified values such as loads, Durometer, volume fractions) are defined by the desired working requirements including drag or push through force (0-10 lbs) and leak rate (0-270 cc/min) to be achieved. The working requirements ofelongated seal104 are encompassed by the Z-axis variables. The X-axis variables are (1) the seal diameter from the initial to the expanded diameter and (2) the number of yams in the seal. The Y-axis variables are (1) durometer, (2) surface cover factor, (3) density of yam to free space, (4) thickness of polymer, (5) geometry of the seal zone and (6) braid angle. The X-axis variable and the Y-axis variables are optimized to produce the desired Z-axis parameters forelongated seal204.

In the design volume shown above, the preferred seal structure will have a drag force of 0-5 pounds, a leak rate of 0-270 cc per minute, an elastomeric material durometer of 10-80 shore A, frictional properties as per ASTM D1894 (plastic film and sheeting) between 0.07 and 0.5, a cover factor of 0-1, a density of strands to free space of 10-70%, a elastomeric material thickness of 0.003-0.015 inches, a constricted area length of 2-0.1 inches, a braid angle of 0-90 degrees, an initial to expanded seal diameter of 3-18 mm, and a strand count of 30-200.

A more preferred seal structure will have a drag force of 0.5-1.5 pounds (when used with larger sized instruments having a diameter of about 10-14 mm), a leak rate of 0-120 cc per minute, an elastomeric material durometer of 10-30 shore A, a coefficient of friction of 0.07-0.18, a cover factor of about 1, a density of 70%-100%, an elastomeric material thickness of 0.003-0.010, a constricted area length of 0.5-1.5 inches, a braid angle of 0-60 degrees, an initial to expanded seal diameter of 4-15 mm and a strand count of 100-160.

FIGS. 10-11 illustrate an alternate embodiment of the present disclosure. Thisaccess apparatus250 is substantially similar to the embodiment ofFIGS. 1-6, but incorporates aseal mount252 disposed withincannula sleeve102 adjacent distal end of cannula sleeve.Seal mount252 is affixed to the distal end ofelongated seal204, in the same manner as discussed above in connection withcannula tip216, and is mounted for axial movement within thecannula sleeve102 between an extended position shown inFIG. 9 and a retracted position shown inFIG. 10. Specifically,seal mount252 includes opposedkeys254 which are received withininternal recesses256 ofcannula sleeve102. Desirably, recesses256 do not extend through to the exterior surface of thecannula sleeve102.Keys254

traverse recesses

256 to permitseal mount252 and the distal end ofelongated seal204 to move in an axial direction. In this manner,elongated seal204 may be sufficiently taut when mounted withincannula sleeve102, i.e., substantially devoid of excess slack material.FIG. 10 illustrates the arrangement ofelongated seal204 and sealmount252 when a relatively small diameter instrument is positioned withinaccess apparatus100. As shown, an area ofelongated seal204 around thecenter220 forms a fluid-tight-relationship with the instrument whileseal mount252 is in a first position. With reference toFIG. 11, upon insertion of a larger diameter instrument,seal mount252 moves in a proximal retracting motion to permit an area ofelongated seal204 around thecenter220 to expand while still maintaining a fluid tight seal about the instrument. The area ofseal204 that engages the instrument is greater inFIG. 11, as compared toFIG. 10.Access apparatus250 may also include aseptum seal258 mounted at the proximal end ofcannula housing104 to provide additional sealing capabilities.Septum seal258 may be any of the seal arrangements described hereinabove. Both theseptum seal258 and duckbill valve shown open to accommodate the instrument inserted into the access apparatus.

FIGS. 12-14 show a cannula assembly according to an alternate embodiment of the present disclosure.Elongated seal500 includesproximal flange502,tubular member504 extending from theproximal flange502 andcannula tip506 mounted to the distal end of thetubular member504.Tubular member504 includes abraided fabric505 with anexternal elastomer coating508.Proximal flange502 may be integrally formed withelastomer coating508 or affixed to the proximal end oftubular member504.Elongated seal500 includes a general hourglass shape tapering inwardly from the proximal end to aconstruction510 and tapering outwardly from theconstruction510 to the distal end of thetubular member504. The hourglass configuration is formed during the manufacturing process by placing the tubular braid on a corresponding hour-glass shaped mandrel and forming the elastomeric material over the braid in accordance with any of the techniques discussed hereinabove.

In a preferred embodiment,elastomer coating508 incorporates a pair ofrib portions512

adjacent construction

510.Rib portions512 provide an area of increased elastomer thickness to effectively increase the resiliency ofcentral portion510 oftubular member504. This increased resiliency ensures the formation of a fluid-tight seal about the instrument and facilitates return of thecentral section510 to its original diameter subsequent to removal of an instrument.Rib portions512 may be incorporated within the mold (compression or injection) as correspondingly dimensioned recesses in the mold which receive the elastomer over-flow. Alternatively,rib portions512 may be separate elastomer bands adhered to the outer surface ofcentral section510 ofelongated seal500.

FIGS. 15-16 illustrate a cannula assembly according to an alternate embodiment.Cannula sleeve102 includes anexternal thread150 formed on its outer surface.Thread150 facilitates insertion of thecannula assembly100 within the tissue site. Specifically, rotational movement of thecannula assembly100 causes thethread150 to engage the tissue and cause advancing movement within the body cavity.Thread150 is shown as continuous; however,thread150 could include partial interrupted thread segments and still be effective in advancingcannula assembly100 within tissue.

Cannula sleeve

102 may also include anopening170 in its outer surface. Opening170 permits passage of insufflation gases between outer space (defined between theelongated seal500 and cannula sleeve102) and the abdominal cavity to either maintain insufflation within the body cavity and/or permit gases to enter or exit the outer space to equalize pressure of the outer space with the abdominal cavity and the internal passage of theelongated seal504. In this embodiment, the elongated seal may be entireably impermeable to insufflation gases.

While the invention has been particularly shown, and described with reference to the preferred embodiments, it will be understood by those skilled in the art that various modifications and changes in form and detail may be made therein without departing from the scope and spirit of the invention. For example, persons of ordinary skill in the art may devise alternative means for mounting the slit seal or elongate seal, which would be contemplated herein. In addition, the slit seal may be omitted and the elongate seal may be arranged to block the passage through the cannula sleeve. In further embodiments, different means for introducing insufflation gases, such as a passageway incorporated in or secured to the cannula sleeve. In other embodiments, the braided or other fabric material is formed in a layer, and the ends of the layer are stitched together or otherwise joined together to form a tubular shape. In further embodiments, the elastomeric portion extends only over the upper portion of the fabric material. In further embodiments, the elastomeric material is omitted and the fabric material is relied upon to form a seal with instruments. Accordingly, modifications such as those suggested above, but not limited thereto, are to be considered within the scope of the invention.