Note: Descriptions are shown in the official language in which they were submitted.
CA 02244893 1998-07-27
WO 97!29680 _~_ PCT/US97102056
SURGICAL ACCESS DEVICE AND METHOD
OF CONSTRUCTING SAME
Field of the Invention
The present invention relates generally to surgical access devices for use in
endoscopic surgery, such
devices comprising introducers, endoscopic sheaths, catheters, endoscopes,
cannulas, and the like, and, more
particularly. to surgical access devices having secondary channels for the
post-introduction insertion of endoscopic
surgical instruments, and to a method for constructing such channels.
~ackaround of the Invention
The advantages of minimally invasive surgery are well known and understood.
Essentially, through the use
of advanced endoscopy and other vision systems, surgery can be performed
percutaneously through one or more small
incisions or portals formed in the patient's body or through a bodily orifice,
such as vagina, cervix, urethra, rectum,
mouth. etc. Entrance to the body is accomplished in a number of ways depending
upon the type of procedure. Once
a portal or "port" is formed in the patient's body, a number of surgical
access devices may be placed therethrough
in order to perform the endoscopic procedure. Such devices will typically
include some form of endoscope or other
vision system to allow the surgeon to visualize the procedure. However, other
surgical access devices may be used
in combination with an endoscope, such as an introduces, an endoscopic sheath,
catheters, or other cannuias. Thus,
endoscopes and other endoscopic surgical instruments may be inserted through
these surgical access devices which
may have one or more instrument channels formed therein. Such surgical access
devices may be reusable and, thus,
require sterilization (such as most endoscopes), or may be disposable (such as
introducers, endoscopic sheaths, etc.).
'~llinimally invasive surgery obviously reduces the trauma and pain to rite
patient, accelerates recovery, and
shortens the average hospital stay, thus minimizing the costs of health care
in the U.S. and around the world. In
addition to minimal invasiveness. there is also a trend to attempt to perform
unanticipated procedures during the
initial surgery so as to avoid scheduling repetitive surgeries. That is, for
example, frequently a diagnostic procedure
is scheduled for a given purpose; however, once inside the patient, the
surgeon notices a cyst, polyp, lesion. or other
suspicious pathology. Therefore, the surgeon may desire to perform a biopsy or
other surgical procedure. If an
additional diagnostic or therapeutic procedure could be accomplished
concurrently with the initial procedure,
substantial savings in patient comfort, recovery time, and costs could be
realized. However, presently in most cases,
the patient must be rescheduled for a later procedure.
Although it is known in the prior art to provide auxiliary, expandable
channels in surgical access devices,
3D they have apparently not met with commercial success. A number of reasons
may be postulated.
Although it is understood that the surgical access device must initially have
a small cross-sectional profile
for ease of insertion, the means for expanding that device have varied.
Typically, such expansion means comprises
eocnn~lary r~r ativiliarv rhannol haying 3 liiman for th_a ineertinn gf or
~,ndoscnpe or other endoscopic instrument.
Thus, the main lumen of the surgical access device is formed by a hollow
channel defined by a certain wall of
thickness. The cross-sectional profile of the surgical access device is
usually circular, although ocher profiles have
been utilized. As used herein, "profile" will mean a cross-sectional profile
unless otherwise specified. Thus, the goal
CA 02244893 1998-07-27
WO 97/29680 PCT/US97/02056
_2.
of present access devices is to minimize their profile upon initial
introduction. Following insertion, however, it is
desirable to form a secondary channel in the device for the insertion of a
second instrument in order to complete
the intended procedure or another unanticipated nrnrednrP. Thic s~cnndarv
channPi is typically 6arme~ from 2
polymeric or rubberized elastic material. Due to their elastic nature, such
secondary channels have substantial wall
thicknesses. Moreover, in order to minimize the profile of the device upon
insertion, these secondary channels must ,
be collapsed in some fashion upon insertion. Thus, the cross-sectional wall
thickness of the secondary channel must
lie upon the outer diameter of the main channel, thus adding significantly to
the overall profile of previous surgical
access devices. This construction adds a new problem to the one the device is
attempting to solve.
The most commonly proposed solution to the extra profile added by the
secondary channel, is to surround
t 0 it with an outer sheath or other elastic band, in order to hold it in a
collapsed state around the outer diameter of
the main channel of the surgical access device. However, this approach simply
aggravates the problem due to the
wall thickness of the outer sheath or banding. Moreover, these outer materials
add to the radial resistance which
must be overcome in order to push the instrument through the secondary
channel. In addition, and quite significantly, ,
the elastic nature of previous secondary channels presents severe frictional
disadvantages, further intensifying the
problem of instrument insertion. Moreover, in reusable systems, the outer
sheathing or banding, which causes a
secondary lumen to collapse, presents a substantial problem with respect to
sterilization.
Another significant disadvantage of prior secondary channels is that they are
elastically expandable, both
longitudinally and radially. Thus, upon either insertion andlor deployment of
secondary instrument, the channels may
became loose or gathered. Thus, upon insertion of the instrument, there might
be bunching or binding, which
prevents the instrument from smoothly accessing its desired location. This
requires the application of greater farce
on the instrument, thus increasing the pain and trauma to the patient which is
intended to be avoided by the surgical
access device. That is, most procedures of this type are performed on an out-
patient basis with the patient
undergoing only a local anesthetic. Thus. the difficulties associated with
previous secondary channels, including their
more frictional nature, increases the likelihood that the procedure will be
uncomfortable and even traumatic far the
patient.
Moreover, because of the elastic nature of previous secondary channels, they
require an additional hollow
tube to hold them in the open position for repetitive instrument insertion.
Furthermore, there has been a Pack of
attention to leading edge design, so as to avoid contamination upon insertion
of prior art surgical access devices.
This is particularly a severe problem in connection with the usable systems
which require sterilization between use.
Thus, there are substantial problems associated with secondary channels formed
in a prior art surgical
access devices. Moreover, previous devices have not addressed advances in
endoscopic design. That is, initially
endoscopes were of the straight and rigid rod lens type, or the more costly
flexible scopes with articulating distal
ends. ~LiiVav~~, rfUPC ~Cc'6~tt JCIIII'llt'tU CndUJLUFlGJ 61C Jllltiller In
diameter and allow some flexibility in use, unlike
rigid scopes. Semi-rigid endoscopes present new obstacles, but also additional
opportunities, with respect to auxiliary
channels, which opportunities have not been addressed by previous surgical
access devices.
CA 02244893 1998-07-27
3-
Accordingly, there is a severe need in the prior art for surgical access
devices and methods for constructing
them which can successfully provide secondary or auxiliary surgical channels.
Summary of the Invention
The present invention satisfies this need in the prior art by providing a
surgical access device and method
of constructing same wherein the secondary or auxiliary lumen comprises a
guide channel formed from an extremely
thin, but very strong and substantially noncompliant membrane. This guide
membrane exhibits performance
characteristics which make it preferred for this application.
The wall thickness of the membrane is so thin (approximately .001 inches (.254
mm) in some embodiments)
that it has only a negligible affect on the profile of the present surgical
access device. This is true even though the
membrane may be pleated, folded, or doubled back on or around the outer wall
surface of the surgical access device.
Thus, the guide membrane of the present invention is compatible with very
small diameter access devices which are -
more commonly being used with rigid and especially semi-rigid endoscopes.
Accordingly, the surgical access device
of the present invention is able to substantially reduce the pain and trauma
associated with endoscopic procedures.
One important advantage of the present membrane is that it can be formed or
set in position on the surgical
access device. That is, by the use of heat-forming or heat-shrinking
techniques, or other mechanical or chemical
(e.g., adhesives) means, the membrane can be "set" in order to closely conform
to the o~rter surface configuration
of the access device, thus maintaining a narrow or otherwise small profile.
Moreover, outer elastic sheathing, straps,
or binding of any type are unnecessary; thus, the profile of the access device
is further minimized. An additional
advantage of the present membrane is its lubricity. That is, the material in
its natural state as formed on the access
device is lubricous or otherwise less-adhesive, thereby facilitating inserting
of the access device and reducing
discomfort.
The guide channel membrane of the present invention can be constructed from
any one of a number of
highly oriented or cross-linked, noncompliant materials, including, without
limitation, polymers. Such polymers may
preferably undergo an extrusion process in order to achieve their high
orientation status, resulting in their
noncompliant and substantially inelastic nature. Moreover, such extruded
polymers are also very strong and tough,
and lubricous as pointed out above.-In the preferred embodiment, one guide
channel membrane material is
polyethylene terephthalate ("PET"); although other materials within that group
are possible, examples being polyolefins
and their blends which can be highly orientated or cross-linked after
radiation treatment and heat forming as found
in the art of balloons for angioplasty catheters. Other materials include
nylon and polyethylene which achieve
orientation by pre-stretching whereby the material has high strength and
little elongation when a load (stress) is
exerted upon it. '
The guide channel membrane may be formed from material having various
thicknesses, depending upon the
application of the particular surgical access device; however, thicknesses in
the range of .0005 inch (.127 mm) - .002
inch (.508 mm) are preferred. Thus, it can be seen that such membranes do not
add significantly to the profile of
the access device.
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CA 02244893 1998-07-27
-4-
Another advantage of the guide channel membrane of the present invention is
that they are "releasable"
upon dilation. That is, although heat formed or otherwise set so as to closely
conform to the outer configuration
of the access device, the membrane material can easily open up or release to
form a secondary guide channel. In
most cases, dilation can be achieved by the secondary endoscopic instrument
itself, without a need for a dilator or
obturator. Thus, these additional steps can be avoided. Moreover, the
materials are also internally lubricous, thus,
minimizing resistance to instrument insertion and advancement. The lubricous
nature can also eliminate the need for
additional layers of material, such as Teflon and their coatings, which can
add profile as well as cost to the device.
Since the membrane material is not elastic and is otherwise releasable, there
is no radial resistance to instrument
advancement. In addition, no internal support is necessary. That is, once the
membrane material has been released,
it forms a secondary channel which conforms to the nature of the tissue around
it. In other words, if the tissue
surrounding the access device and secondary channel is tight, the membrane
will collapse and conform at the tissue
in order to avoid unnecessary trauma. On the other hand, if the passage is
expanded or dilated, the channel,
following release, will maintain its general channel-like shape, without the
need for any auxiliary internal tubing or
support from any media such as fluid. Thus, the membrane will maintain its
configuration even with the instrument
removed.
The guide channel of the present invention is self-adjusting. That is, the
membrane material will release
to form a secondary channel which is only large enough to admit the passage of
the instrument being advanced
through it. Thus, the guide channel holds the instrument securely along its
path as it is advanced to the distal end
of the access device. This advantage also allows for insertion of instruments
having various cross-sectional profiles,
thus avoiding the need to design secondary channels specifically for certain
instruments. In certain embodiments,
perforations or slits may be formed in the guide channel in order to
facilitate release or dilation.
As noted above, the guide channel membrane is distensible, but substantially
noncompliant. l hus, it will
not expand elastically upon insertion or dilation, either longitudinally or
radially. It will be understood that the term
"radially" is intended to mean in an outward direction, the cross-sectional
configuration of the present guide channel
not being limited to a circular or cylindrical configuration. Thus, the guide
channel will not bunch up or bind as the
instrument is advanced through it. Moreover, because of its toughness and
strength, repetitive insertions of the
instrument without failure are readily achievable, especially in tight or
strong tissue, such as experienced in
laparoscopic applications. In addition, the membrane under these conditions
will not experience longitudinal expansion,
which could result in the guide channel extending beyond the distal end of the
introducer, thereby blocking or
obscuring vision of the endoscope. -
Upon withdrawal, the guide channel membrane is easily collapsible so as to
minimize any pain or trauma.
Moreover, with the application of a slight vacuum, the membrane will conform
closely to the outer surface
configuration of the surgical access device for easy withdrawal.
The surgical access device of the present invention can be constructed from
inexpensive materials and in
accordance with simple construction techniques. This is particularly true of
the guide channel membrane. Thus, the
access device is disposable, thus avoiding problems associated with
sterilization. Moreover, the membrane is
CA 02244893 1998-07-27
compatible with any type of surgical access device, including introducers,
endoscopic sheaths, catheters, cannulas,
and endoscopes themselves.
In accordance with another advantage of the present invention, one embodiment
of the membrane described
above is used to form a guide channel on the surgical access device. Unlike
secondary channels of the prior art,
the present guide channel can be used to guide an instrument through a bend or
curve as may be experienced in a
procedure using a semi-rigid endoscope. In other words, such endoscopes are
often used in connection with curved
introducers which allow them to navigate certain curved anatomical paths
andlor to move or visualize tissue. Thus,
in accordance with one aspect of the present invention, the guide channel is
nonlinear. Such a channel can be
formed upon a guide platform which is formed on or is otherwise associated
with the access device. Moreover,
guide rails can be formed to further provide structure and rigidity to the
secondary channel. The bends or curves
formed in the guide channel to orient the secondary lumen so that the
instrument can arrive at a specific distal
location with respect to the primary lumen, depending upon the procedure.
The guide platforms or rails can take on a number of configurations.
Advantageously, however, due to the
formable and thermoplastically settable nature of the channel membrane, the
channel membrane can be folded or
arranged with respect to the access device in a wide variety of ways.
The surgical access device of the present invention also exhibits a particular
distal end design which avoids
contamination. Upon insertion of the device, the instrument channel is sealed
so as to avoid entry of tissue or
foreign contaminating material. Due to the thermoplastic nature of the channel
membrane, the seal can be
accomplished by heat forming the channel at the distal tip. Alternatively, a
narrow profile tip can be designed which
plugs the distal opening of the secondary channel while still facilitating
entry of the access device. Like the distal
end of the present access device, the proximal end also features a particular
"y" design which facilitates
advancement of a secondary instrument into the guide channel while minimizing
risk of damage to the device or
discomfort to the patient. The proximal end of the access device is provided
with a housing which gently introduces
the instrument along a path which eventually becomes tangential to the main
longitudinal axis of the access device.
The housing which surrounds the proximal end is also provided with appropriate
valves to control and regulate the
in-flow and out-flow of distension media, irrigation fluid, or other fluid.
As noted above, the guide channel of the present invention can be integrally
formed on the insertion tube
of an endoscope or separately formed on an introducer, endoscopic sheath, and
the like. In the latter case, the
introducer can be designed and constructed so as to guide the entrance of the
secondary instrument in a particular
way in order to achieve a specific purpose, depending upon the procedure being
accomplished. Moreover, the
instrument can enjoy a lumen independent of any movement of the endoscope
which is inserted through the main
channel of the introducer.
In accordance with the method of construction of the surgical access device of
the present invention, as
noted above, the settable nature of the membrane material facilitates a number
of construction arrangements and
techniques. Thus, the membrane material can be folded or stored with respect
to the access device on an exterior
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CA 02244893 1998-07-27
surface, interior surface, or other intermediate location. It can be coupled
to the access device by a wide variety
of means, including mechanical, adhesive, heat formation, etc.
Thus, in accordance with a preferred method, the surgical access device of the
present invention is
constructed from a main tube which provides a main channel for the access
device. The main tube can be
constructed from stainless steel tubing or a rigid plastic such as
polycarbonate which can provide strength with little
wall thickness. Typically, the main channel provides access for insertion or
introduction of an endoscope; however,
other instruments can be introduced into the patient as well through the main
channel. The guide channel membrane
is formed onto the main tube in the following manner. The membrane is provided
in the form of a hollow tube,
which is typically extruded to form that shape, so as to have an outer
diameter which is greater than that of the
main tube. The membranes can be constructed from PET tubing which can came in
the form of balloon tubing which
is pre-stretched and highly orientaiEd for minimal elongation. "usher
constructions of membranes can use poiyoiefins
and their blends, polyethylene, and nylons which are highly orientated or
cross-linked. The guide channel membrane
tube is placed over the main channel tube and positioned eccentrically with
respect to the axis thereof.
A split tube sheath is mechanically clamped over the main tube capturing the
guide channel membrane tube
against the main tube. The split tube can be made from nylon 11 which has high
strength with little wall thickness.
Other materials such as polycarbonate, polyethylene, urethane, and the like
can be employed. The split channel can
be mechanically affixed to the main tube or be placed onto the main tube by a
variety of adhesive agents or thermal
bonding techniques. The actual width of the slit itself can vary which will
affect the profile and guiding
characteristics of the membrane channel. The excess membrane material, owing
to the fact that its outer diameter
is greater than that of the main tube, is allowed to escape through the slit
in the sheath and extends outwardly
therefrom. This excess material is then folded, pleated, or otherwise stored
with respect to the main tube in any
one of a variety of ways so as to minimize the profile of the surgical access
device. Typically, the excess membrane
material is folded or doubled back on .itself so as to closely conform to the
outer surface configuration of the tube.
An intermediate amount of heat, such as approximately 160°F, is then
applied to the membrane material so as to
heat form or set it in position closely conforming to the main tube, although
other mechanical forming or adhesive
techniques may be employed. The settable nature of the membrane is such that a
crease or seam formed in the
pleated material will retain a sharp, narrow profile, thus facilitating entry
and use and avoiding damage or distortion
to the guide channel under these conditions.
In accordance with another method of construction and introducer embodiment,
an even narrower profile
introducer can be constructed without the need for an outer split sheath. In
this case the guide channel membrane
tube is heat bonded or otherwise coupled directly to the hypotube by adhesive
or other means. To facilitate this -
construction, the membrane tube can be supplied in a multi-lumen or figure-8
configuration, wherein the membrane
- is constructed from an extrusion or other process. Moreover, one or more of
the lumens may be collapsible, and .
the others may be noncollapsible, either due to their increased wall thickness
or to rigidifying means such as
hypotubes or reinforcement devices, etc.
n: ST,'-' S_T
...
CA 02244893 2005-07-20
In accordance with another step of the present method, a merge channel may be
formed along the main
channel in order to provide for the easy insertion of a secondary instrument
into the guide channel. The merge
channel can be constructed from a variety of materials arcluding nylon 11 and
other polymers as well as stainless
steel which can be flexed yet retain radial integrity. As noted above, the
merge channel is proximally located with
respect to the surgical access device and remains substantially out of the
body. In accordance with the present
method, the merge channel tube is longitudinally aligned with respect to the
axis of the main tube prior to the over-
wrapping of the guide channel membrane tube. Thus, the proximal end of the
membrane tube circumscribes both
the main tube and the distal end of the merge channel tube and the guide
channel is simultaneously formed around
both the main tube and the merge channel tube to comprise the "y" junction of
the surgical access device. To
provide mechanical strength at this "y" junction, a housing or other
mechanical clamping means is provided. The
housing can take a variety of forms to provide ergonomic benefits to the
operator or clinician. in construction, it
can be made from a variety of injection molded plastics including
polycarbonate, polysutfone, nylon, etc., or machined.
It can be a part of the disposable introducer or a separate unit which is
reusable, re-sterilized, and placed back onto
the surgical access device by the operator prior to each use.
In another step of the present invention, the distal tip of the surgical
device is sealed so as to prevent
contamination or distortion of the guide channel upon insertion of the access
device into the body. likewise, at the
proximal end of the access device, the main channel and merge channel are
provided with the necessary valuing for
irrigation or distention media. The valuing must prevent any leakage around an
instrument or endoscope when these
devices are placed through the ports and typically has an 0-ring or washer
type structure. In add'ttion, they must
contain structures such as duck-bill or star valves which prevent the back
flow of media through the ports when
no instrument or endoscope is through the port. These valves can be made from
silicone, rubber, and other
elastomeric materials which are known in the art.
Thus, in summary, the surgical access device of the present invention
comprises a first channel having a
first lumen for the insertion of an instrument, endoscope, or other
visualization device, and at feast one secondary
channel for providing an auxiliary lumen for the insertion of an instrument,
endoscope, or other visualization device,
wherein the secondary channel is mounted along the outer surface of the
surgical access device and is constructed
from a thin pleated membrane which, prior to dilation of said secondary
channel, so closely conforms to the outer
surface of the device so as to only negr~gibly increase the sae of the profile
of the device. The present invention
further comprises a surgical access device as described above, wherein the
secondary channel is constructed from
a membrane which is self-conformable to the device and which is settable, so
as to closely conform to the surgical
access device.
Accordingly, a surgical access device of the present invention and the method
of constructing it provide a
substantial advancement over the prior art.
CA 02244893 2005-07-20
-~a-
Various embodiments of this invention provide a surgical access device for
providing one or more
auxiliary lumens for inserting one or more components into a patient's body,
said surgical access device
having an outer surface defining at any particular location along its
longitudinal axis, a cross-sectional profile,
said device comprising: a first channel providing a first lumen for the
insertion of one of said components;
and at least one secondary channel providing an auxiliary lumen for the
insertion of another of said
components, said secondary channel being mounted on said surgical access
device so as to be positioned
along said outer surface thereof, said secondary channel being constructed
from a substantially inelastic
flexible membrane having a pre-dilated position and a dilated position, which,
in the pre-dilated position, is set
in a self-retaining position which closely conforms to said outer surface.
Various embodiments of this invention provide a surgical access device for
providing one or more
auxiliary lumens for inserting one or more components into a patient's body,
said surgical access device
defining at any particular location along its longitudinal axis a cross-
sectional profile, said device comprising:
a first channel having a first lumen with an open distal end for the insertion
of one of said components; and at
least one secondary channel adapted to be dilated, said secondary channel
providing an auxiliary lumen for
the insertion of another of said components, said secondary channel
constructed from a substantially
noncompliant membrane which is self-conformable to the outer surface of said
device such that, prior to
dilation of said secondary channel, said membrane is folded to minimize the
profile of said surgical access
device.
Various embodiments of this invention provide a surgical access device for
providing one or more
auxiliary lumens for inserting one or more components into a patient's body,
said surgical access device
having an outer surface defining at any particular location along its
longitudinal axis a cross-sectional profile,
said device comprising: a first channel having an open distal end providing a
fiirst lumen for the insertion of
one of said components; and at least one secondary channel adapted to be
expanded from a first pre-dilated
position to a second dilated position providing an auxiliary lumen for the
insertion of another of said
components, said secondary channel being constructed from a substantially
noncompliant membrane which,
prior to dilation of said secondary channel, is self-retained in said pre-
dilated position along the outer surface
of the device, such that said membrane closely conforms to said outer surface.
Various embodiments of this invention provide a surgical access device,
comprising: a first channel;
and at least one secondary channel providing an auxiliary lumen for the
insertion of at least one component,
said secondary channel being constructed from a substantially inelastic
membrane having a first storage
position and a second released position in which said membrane is dilated so
as to allow passage of said
component.
Various embodiments of this invention provide a channel adapted to be used
with a surgical access
device so as to provide an auxiliary lumen for the insertion of a component,
said channel comprising: a
substantially noncompliant membrane which is thermally, mechanically, or
chemically settable, or any
CA 02244893 2005-07-20
-7b-
combination thereof, so as to be self-retained in a first folded pre-expanded
position and capable of being
unfolded to form different channel configurations.
Various embodiments of this invention provide the use of a surgical access
device of this invention
for insertion of one or more components into a patient's body. Such a
component may include an instrument
and/or a visualization device such as an endoscope.
Various embodiments of this invention provide use of an access device having a
proximal end, a
distal end and an elongate body extending therebetween for providing access to
an internal site in a patient,
said device comprising a first lumen having a substantially fixed interior
cross-sectional area and an open
distal end and at least one second lumen defined at least in part by a
substantially inelastic flexible wall, said
second lumen having an internal cross-sectional area that is movable from a
first, reduced area to a second,
enlarged area; wherein the first, reduced cross-sectional area configuration
of the second lumen is for
facilitating advancement of the device into the patient; and enlargement of
the cross-sectional area of the
second lumen from the first, reduced cross-sectional area to the second
enlarged cross-sectional area is for
provision of access to the internal site in the patient by way of said second
lumen.
Various embodiments of this invention provide the use of an elongate rigid
walled introducer for
enlargement of the effective diameter of an access site of a patient, the
elongate rigid walled introducer
having an elongate tubular body with at least a first lumen extending axially
therethrough and defined within a
substantially rigid wall, the wall defining the first lumen having a radially
inwardly facing surface and a radially
outwardly facing surface, the introducer also having at least a second lumen
extending axially through the
body radially outwardly from the first lumen, said second lumen comprising a
collapsible wall, wherein
collapse of the wall of the second lumen against the outwardly facing surface
of the wall defining the first
lumen is for facilitating introduction of the introducer into the patient and,
expansion of the collapsible wall to
restore the second lumen is for enlargement of the effective diameter of the
access site.
Various embodiments of this invention provide a method of manufacturing a
multilumen access
device, comprising the steps of: providing a substantially noncompliant,
flexible tubular sleeve having a
central lumen extending axially therethrough, said sleeve also having a
radially inwardly facing surface
thereon, said inwardly facing surface being larger than said outwardly facing
surface of said tubular element;
positioning the tubular element eccentrically within the tubular sleeve;
securing the inwardly facing surface of
the tubular sleeve to the outwardly facing surface of the tubular element
circumferentially around the tubular
element through an angle of at least 180°; and folding the excess
tubular sleeve to closely conform to the
outer surface of the tubular element.
Brief Descriation of the Drawin4s
FIGURE 1 is a side view of the surgical access device of the present invention
illustrating a partially
inserted endoscope and a secondary instrument in a pre-introduction location.
- . CA 02244893 1998-07-27
-$-
FIGURE 2 is a close-up side view of the access device illustrating the
advancement of the secondary
instrument through the guide channel of the present invention.
FIGURE 3 is a cross-sectional view of the access device taken along line 3-3
of FIGURE 2 illustrating the
main channel and guide channel in their initial state upon insertion of the
access device into the body and prior to
deployment of a secondary instrument through the guide channel.
FIGURE 3a is a cross-sectional view of the access device illustrating an
alternative embodiment of the main
channel and guide channel prior to deployment of a secondary instrument
through the guide channel.
FIGURE 3b is a cross-sectional view of the present access device illustrating
an alternative embodiment for
the guide channel which does not utilize a split sheath.
FIGURE 3c is a cross-sectional view of the access device of FIGURE 3b,
illustrating the guide channel in
its deployed or released position. -
FIGURE 4 is a cross-sectional view of the access device taken along lines 4-4
of FIGURE 2 illustrating the
guide channel of the present invention in a released or expanded state as the
secondary instrument is advanced
therethrough.
FIGURE 5 is a graph illustrating the stress-strain relationship of oriented
PET, as used far the guide channel
membrane, in comparison with a typical elastomer.
FIGURE 6 is a graph illustrating the relationships between tube diameter and
internal pressure for tubes
comprising PVC, polyolefins, and PET material.
FIGURE 7 is a close-up perspective view of the distal tip of the present
access device illustrating a bend
or nonlinear curve which may be formed in the device, and further illustrating
the manner in which the present guide
channel allows a secondary instrument to conform to such curve.
FIGURE 8 is a close-up, broken-away view of the access device of FIGURE 6
illustrating a guide platform
or guide rail formed in conjunction with guide channel which guides and
supports the secondary instrument along the
curved guide channel.
FIGURE 9 is a cross-sectional view of another embodiment of the surgical
access device of the present
invention illustrating other guide channel and guide platform configurations,
together with the manner in which the
guide channel membrane is formed with respect thereto.
FIGURE 10 is another embodiment of the guide channel of the present invention
illustrating a guide channel
membrane which is perforated or otherwise slit in order to exhibit unique or
specialized release characteristics.
FIGURE 10a is the guide channel embodiment of FIGURE 10 with an instrument
deployed substantially along -
the length of the guide channel.
FIGURE 11 is a close-up perspective view of the distal tip of the present
access device illustrating the
manner in which the guide channel may be sealed to prevent contamination or
damage to the guide channel upon
introduction of the access device into the body.
- . CA 02244893 1998-07-27
-9-
FIGURE 11a is a close-up perspective view of an alternative embodiment of the
distal tip of the present
access device illustrating another manner in which the guide channel may be
sealed to prevent contamination or
damage to the guide channel upon introduction of the access device into the
body.
FIGURE 12 is a longitudinal cross-sectional view taken through the proximal
housing of the present access
device in order to illustrate the merge channel leading into the guide channel
of the present invention.
FIGURE 13 is a cross-sectional view taken along lines 13-13 of FIGURE 12
illustrating the merge channel
and main channel distal the proximal housing of the present access device.
FIGURE 14 is an exploded view of the present access device illustrating the
method of its construction.
FIGURE 15 is an elevational view along the longitudinal axis of the distal end
of another embodiment of
the present invention comprising an introducer having an open-loop formed
thereon.
FIGURE 16 is a cross-sectional detail view of the open-loop of FIGURt 15
showing a hose farmed
therethrough.
FIGURE 17 is a cross-sectional view showing the open-loop introducer of FIGURE
15 with an aspiration tube
positioned in the guide channel.
FIGURES 18 and 18a are cross-sectional views of another embodiment of FIGURES
3 and 3a, illustrating
the main or laparoscopic channel of the access device and a secondary guide
channel which is shown in its initial
storage or collapsed position with respect to the access device body and prior
to the deployment of a secondary
instrument through said guide channel.
FIGURE 19 is a cross-sectional view of the embodiment of the present access
device shown in FIGURES
18 and 18a, as taken along lines 4-4 of FIGURE 2, illustrating the guide
channel of the present invention in a
released or distended state as a secondary laparoscopic instrument is advanced
therethrough.
FIGURE 20 is a cross-sectional view of the laparoscopic embodiment of the
access device of the present
invention illustrating an alternate embodiment of the guide channel.
FIGURE 21 is a cross-sectional view of the access device of FIGURE 20
illustrating the insertion of a
secondary instrument along the guide channel.
FIGURE 22 is a close-up side view of an alternate distal tip of the present
access device.
FIGURE 23 is a close-up view of the distal tip of another embodiment of the
surgical access device
illustrating the secondary instrument and the uterine tissue being visualized
by a hysteroscope.
Detailed Description of the Preferred Embodiment
With reference to FIGURE 1, there is shown the surgical access device 100 of
the present invention. In
- this case, a surgical introducer has been selected to illustrate the
principles of the present invention; however, it will
be understood that such principles apply equally to all types of surgical
access devices, as well as to devices not
necessarily limited to surgical access. In the broadest sense, the principles
of the present invention encompass
devices where secondary channels or other types of guide channels, expandable
or otherwise, are desirable or
necessary in order to allow passage of some type of instrument. Such devices
include, without limitation,
introducers, endoscopic sheaths, catheters, cannulas, and the like. The
secondary or guide channels of the.. preset
_ ~ CA 02244893 1998-07-27 . --_.
-10- _ .
invention may be retro-fitted onto such devices or integrally formed therein.
For example, the guide channel of the
present invention may be integrated into the insertion tube of an endoscope
itself.
Furthermore, it will be understood that the present invention is compatible
with all types of instruments,
including catheters, obturators, etc. Also, visualization devices used with
the present access device are not to be
limited to endoscopes, but also include all types of such devices, including
fluoroscopes, etc. Thus, the terms
"instrument" and "endoscope" are intended to be only illustrative and
representative of the wide variety of devices
that can be utilized in accordance with the present invention, and such terms
are not intended to be limiting in any
respect.
Thus, the fact that the present invention is described with respect to an
introduces is illustrative only and
not intended to be limiting in any respect.
Surgical Introduces
Thus, with further reference to FIGURE 1, there is illustrated a surgical
introduces 100 into which the
principles of the present invention have been incorporated. In this case, the
introduces 100 is intended for
gynecological procedures, such as hysteroscopy or cystoscopy; however, again,
a wide variety of procedures may
be performed with the surgical access device 100 of the present invention.
As shown in FIGURE 1, the access device 100 comprises a distal insertion
portion 102, which is intended
for insertion into the patient's body, and a proximal housing portion 104,
which generally remains outside of the
patient's body. In this case, access to the patient's body is achieved through
dilation of the cervix; however, in
other procedures, access may be gained through other natural openings in the
body or by surgical incision, etc. The
details of construction of the insertion portion 102 are described below in
more detail and illustrated in connection
with FIGURES 3 and 4, while the details of the housing portion 104, including
in-flow and out-flow conduits 106,
108, are described and illustrated below in connection with F1GURE 12.
To the left of the proximal housing portion 104 as shown in FIGURE 1, there is
shown in exploded
relationship ~o the introduces 100 an endoscope 110 and a secondary instrument
112, in this case a grasper which
can be used for the removal of foreign bodies or tissue. The endoscope 110 is
shown partially inserted into a main
or endoscopic part 114 formed at the proximal end of the introduces 100. The
secondary instrument 112 is shown
positioned prior to insertion into a secondary or instrument port 116. The
terminology of main or endoscopic port
114 and secondary or instrument port 116 is merely illustrative since the
endoscope 110 is typically inserted into
the main part 114 of the introduces 100, while the secondary instrument 112 is
inserted through the secondary port
116. However, in accordance with the principles of the present invention. this
arrangement can be reversed, or any
other of a wide variety of instruments may be used in connection with the
various ports of the access device. In
addition, multiple ports in addition to two may be formed on the introduces
100, depending upon the nature of the
procedure to be performed.
_ CA 02244893 1998-07-27 '-
.11- _
FIGURE 1 illustrates the introduces 100 prior to and upon insertion into the
patient's body, but prior to
insertion of any secondary instrument. Although not readily apparent from
FIGURE 1, a guide channel 118 of the
present invention is mounted and formed on an exterior surface 120 of the
endoscopic channel 122 which forms the
basic cross-sectional profile of the insertion portion 102 of the introduces
100. Since the secondary instrument 112
has not yet been inserted through the instrument port 116 or through the
proximal housing 104 to the insertion
portion 102, the guide channel 118 for the instrument is virtually
unnoticeable to the eye or touch. Thus, as
illustrated in FIGURE 1, the guide channel 118 adds only a negligible
dimension to the profile of the access device
100, thus minimizing pain and discomfort to the patient. This a particular
advantage in gynecological procedures
which are frequently performed on an outpatient basis and under only a local
anesthetic. Thus, if a secondary
procedure proves unnecessary, there has been no unnecessary discomfort or pain
to the patient since the profile of
the introduces i 00 has been niinirnized. However, if such a secondary
procedure becomes necessary, it can be
readily accomplished with only a minimal intrusion into the body through the
existing port, without the need to
schedule a second surgery. It also has the obvious advantage of not requiring
a pre-dilatation step prior to the
insertion of the introduces 100. In some cases, such as for the cervix,
dilatation of the cervical canal can be painful
to the patient and should be minimized as much as possible. In addition, the
uterine cavity requires distension to
' allow far proper visualization. If the cervix is over dilated during the pre-
dilatation step, excessive cervical leakage
can occur when trying to distend the uterus. Thus, the introduces 100 with its
guide channel 118 and low profile
will minimize pre-dilatation of the cervix and will provide a guide channel
118 with the diameter of the instrument
being used, thereby reducing the leakage potential via an overly dilated
cervical canal.
It will be noted from FIGURE 1 that the guide channel 118 closely conforms to
the outer configuration of
the endoscopic channel 122 without the need for outer sheaths or bands which
would increase the profile thereof.
Moreover, since the guide channel 118 is formed on the exterior 120 of the
endoscopic channel 122, its natural
lubricity provides an important advantage in connection with the ease of
insertion of the introduces 100. However,
it will be noted in accordance with the present invention that the guide
channel 118 may also be formed on or within
the endoscopic channel 122 in other configurations with respect to the
introduces 100. Moreover, multiple guide
channels may be formed on or incorporated into the main or endoscopic channel
122.
FIGURE 2 is a view of the introduces 100 of the present invention illustrating
the deployment of the
secondary instrument 112 as it advances along the guide channel 118. In this
FIGURE 2, the guide channel portion
124 ahead of the instrument 112 is folded over and upon the insertion portion
102 of the introduces 100. The
characteristics of the guide channel 118 at this location are described below
in more detail in connection with the
description of FIGURE 3. However, in the region of a leading edge 126 of the
instrument, a guide channel portion
128 is shown to be releasing its insertion position and gradually expanding so
as to allow the instrument 112 to
advance. It will be noted that, although FIGURE 2 shows expansion or dilation
to be achievable by the use of the
secondary instrument itself, other instruments, hollow tubings, media, or
means are equally available to achieve
expansion in accordance with the guide channel 118 of the present invention.
r
~~fy :r
CA 02244893 1998-07-27--
-12- . . _ . . _ _ _
As the instrument 112 advances, the guide channel 118 gradually releases in
order to maintain the minimum
profile of the introduces 100. Thus, pain and discomfort to the patient are
minimized. Furthermore, the surgical
access device 100 of the present invention makes it possible for more
endoscopic surgical procedures to be
conducted on an out-patient basis with only minimal or local anesthesia.
Such procedures would include those which are planned and scheduled, as well
as secondary procedures
which are unanticipated. In other words, a surgeon may enter a patient's body
endoscopically for the purpose of
a particular, planned diagnostic or therapeutic purpose. Initial insertion of
the introduces 100 is typically
accomplished under the visual guidance of the endoscope 110. However, once
inside the patient's body, under these
visual conditions, it may become necessary or desirable to perform a secondary
procedure using a secondary
instrument 112 inserted through the instrument port 116 and advanced through
the proximal housing portion 104
and into the guide ciia~rnei 1 i8 of the present invention. Thus, regardless
of the initial purpose of the endoscopic
procedure, this secondary procedure can be performed virtually simultaneously
without rescheduling a second
procedure. Moreover, the secondary procedure can be performed with only
minimal discomfort to the patient and
without withdrawing or reinserting the endoscope or any other instruments.
Because of the narrow profile of the
present access device 100, a wide variety of primary and secondary endoscopic
procedures (as well as multiple
procedures of all types) can be safely and efficiently performed on an out-
patient basis. Thus, the high cost of
health care can be contained somewhat.
Guide Channel
An important feature of the present invention which allows these advantages to
accrue is the guide channel
118 of the introduces 100. This guide channel 118 can be described in more
detail in connection with the cross
sectional drawings of FIGURES 3 and 4. FIGURE 3 is a cross-sectional view of
the insertion portion 102 of the
introduces 100 at a location ahead of the advancing instrument 112. FIGURE 3
illustrates the main or endoscopic
lumen 130 for the insertion of the endoscope 110'or other instrument
(although, the endoscope 110 is not shown
in FIGURE 3 for clarity of illustration). This lumen 130 is formed by the
endoscopic channel 122 which may
comprise a tube 132 of various constructions. The endoscopic tube 132 is in
turn surrounded by a larger diameter
split tube or sheath 134. The split in the sheath 134 defines a slit or
longitudinal opening 136. Sandwiched
between the inner endoscopic tube 132 and the outer split sheath 134 is a
membrane 140 which forms the present
guide channel 118. This membrane 140 can initially be formed in the shape of a
tube or other construction.
As shown in FIGURE 3, the membrane 140 surrounds the inner endoscopic tube 132
but, due to its greater
diameter, also extends out of the longitudinal opening 136 in the split sheath
134. This excess membrane material
may be folded back onto the outer surface 120 of the split sheath 134 to form
a double-layer of the membrane 140
along a partial circumference of the introduces 100.
This folded-back portion 124 shown in FIGURE 3, forming pleats 123, 125, is
that portion which defines
the guide channel 118 for the instrument 112, as illustrated in more detail in
FIGURES 2 and 4. However, as
illustrated in FIGURE 3, prior to instrument deployment, the guide channel 118
is defined by a membrane which
closely conforms to the outer surface 120 of the split sheath 134. For
example, the lateral edges of the pleats 123,
'; '.
CA 02244893 2005-07-20
-13-
125 can be provided with thin creases or seams 127, 129, which can be formed
and set in the membrane material.
Thus, the narrow profile of the introduces 100 is maintained. In add-'rtion,
because of the close conformity of the
guide channel membrane 140, it is kas Ukely to be distorted or disturbed upon
insertion of the introduces 100 into
the body. Thus, the guide channel 118 maintains 'tts structural integrity and
avoids patient discomfort even before
insertion of the secondary instrument i 12
The membrane 140 which comprises the guide channel 118 can be extremely thin,
ranging in thickness
between .0005" (.127 mm) and .002" (.508 mm), preferably being about .001"
(.254 mm). Thus, even when doubled
back on itself and lying on the outer surface 120 of the split sheath 134, the
guide channel 118 adds only a
negligible thickness to the profile of the surgical access device 100.
Moreover, the guide channel in its pre-release
position 124 shown in FIGURE 3 wdf hold a set in this pos'ttion and does not
require any external elastic sheets or
strapping to bind 'rt in pos-rtion on the introduces 100.
It will be understood, as noted above, that the present guide-channel 118 can
be formed on or in
connection with surgical access devices of a wide var~ty. Moreover, in 'rts
pre-release position 124 (which 'rt
assumes prior to and even dur~g insertion of the access device 100 into the
body, but prior to deployment of an
instrument 112 through the guide channel i i8), the guide channel 118 can be
stored, wrapped, or folded in a number
of configurations, other than that shown ~ FIGURE 3.
For example, FIGURE 3a shows muhiple pleats or folds 223s 225 of a pleated
portion in the membrane
140 which will facilitate a larger membrane channel 118 and can foNaw a
multitude of folding patterns whip
preferentially unfold upon the exerted force of the insertion element. The
additional material which constitutes these
multiple folds 224 will allow for larger instruments to pass through the
membrane channel 118. Likewise, the folding
pattern of the pleats may be such that all of the pleat is on one lateral side
of the introduces or the other, rather
than the two equal pleats shown in FIGURE 3a.
Although the method of construction of the introduces 100 of FIGURE 2 is shown
and described in more
detail in connecfron w'tth FIGURE 14, 'rt w~ be understood that the endoscopic
tube 132 can be constructed from
a wide variety of materials which provides rigidity and protection for the
endoscope 110. Preferably, such a tube
132 can take the form of a stainksa steel hypotube. Thus, the tube 132 can
provide the rigidity necessary for
initial insertion (especially in difficult procedures such as a laparoscopy),
and can be used to move tissue without
fear of damage to the endoscope 110 within. Moreover, the endoscopic tube 132
can take on a bend or curve, as
illustrated in FIGURE 7, to facil'ttate a particular procedure. With
advancements in rigid and semi-rigid endoscopes,
such curves or bends in introducers can facil'ttate intricate navigational
procedures while not damaging the endoscope.
The curves and bends also direct the visualization area of the endoscope to
preferentially view anatomical structures
not on the axis of the insertion point in the body.
The outer spftt sheath 134, in 'rts typical construction, is smooth and
lubricous in order to facilitate insertion
of the introduces 100. It may be constructed from a durab~, bio-compatible
polymeric material, such as nylon.
Preferably, nylon 11 can be utilaed.
CA 02244893 1998-07-27
- ,-14- ._
It will be noted in connection with FIGURE 3 that typical introducer
construction will include both the
endoscopic tube 132 and the outer nylon layer 134. Thus, the guide channel 118
of the present invention does not
significantly increase the profile of such an access device 100. In this
connection, a number of cross-sectional
introducer configurations will be readily apparent to those of ordinary skill
in tire art, including noncircular
configurations. In addition, a wide variety of endoscopic tube and split
sheath wall thicknesses are within the realm
of the person of ordinary skill; however, preferably, the endoscopic tube 132
would have a wall thickness of
approximately .008" (2.032 mml, while the split sheath 134 would have a wall
thickness of approximately .005"
(1.27 mm).
On the other hand, the versatility of the guide channel of the present
invention allows it to be incorporated
into introducers of even narrower profiles. For example, FIGURE 3b illustrates
a cross-sectional view of an alternate
embodiment of me present introducer which does not utilize an outer split
sheath to capture a guide channel
membrane 340 onto a stainless steel hypotube 332. In this case the guide
channel membrane 340 can be heat
bonded or otherwise coupled to the tube 332 6y adhesive or other means. To
facilitate this construction, the guide
channel membrane 340 can be supplied in a multi-lumen or figure-8
configuration, as illustrated in FIGURE 3c, with
one lumen 330 of the membrane 340 being mounted on the hypotube 332, leaving
the second lumen 342 to be
folded or pleated thereabout to provide a guide channel 324 in the stored
position having pleats 323, 325. Thus,
FIGURE 3c illustrates this mounting position prior to the folding of the
membrane 340, which position is shown in
FIGURE 3b. It will also be noted in connection with the embodiment of FIGURES
3b and 3c that guide channel
membranes having multiple lumens can be provided and mounted on the hypotube
in this or another manner, and then
folded and set in position about the tube in order to provide an introducer
with extremely narrow profile. Thus,
three, four, or more membrane tubes can be mounted, either jointly or
separately, on the introducer so as to provide
multiple lumens. In addition, one or more of the tubes (which can be
constructed from an extrusion or other process)
may be collapsible, while others may he noncollapsible, due either to the wall
thickness of the membrane extrusion
or some other rigidifying or reinforcing mechanism (such as a hypotube or the
like).
With reference to FIGURE 4, there is shown cross-sectional view of the present
introducer 100 through the
insertion portion 102 where the instrument 112 has already advanced. In this
case, the instrument 112 almost
completely occupies a lumen 142 defined by the guide channel 118 of the
present invention. As shown in FIGURE
4, the guide channel 118 is shown releasing its predeployment position to
allow the instrument 112 to easily pass
along the guide channel 118 and into the patient.
The guide channel 118 of the present invention may be constructed from a
membrane 140 which exhibits
a number of advantageous characteristics. For example, in addition to its
external lubricity, the membrane 140 is
also internally lubricous to facilitate the deployment of the instrument 112.
The physical characteristics of the
membrane 140 also allow the- guide channel 118 to be self-adjusting. That is,
as shown in FIGURE 4, the guide
channel 118 releases only to the extent necessary to accommodate the
particular instrument being inserted through
it. If not needed, the membrane 140 remains folded in its set position in the
region indicated by arrows 144 of
CA 02244893 1998-07-27
-15-
FIGURE 4. This advantageous characteristics allows the guide channel 118 to
accommodate a number of instruments
of various cross-sectional dimensions without significantly increasing the
profile of the introducer 100.
Likewise, if the instrument 112 is removed from the guide channel 118, the
membrane 140 causes it to
maintain approximately the same position as it did with the instrument 112
inserted within, thus facilitating
reinsertion of the same instrument or another instrument. For instance, in
this case of removing multiple portions
of tissue from the body, it may be necessary to remove tissue and then
reinsert the instrument 112 hack through
the guide channel 118 to remove more tissue. Thus, there is no radial
resistance to reinsertion which reduces the
risk of damage to the guide channel 118 and discomfort to the patient. If the
instrument 112 is withdrawn upon
completion of the procedure, the guide channel 118 readily conforms to the
external forces applied to it by the
surrounding tissue, thereby causing the guide channel to collapse upon
withdrawal of the introducer 100, so that
~.1"a n 1.,., 'r .1.. ' a 4.. ....;a.. 1 ~ ~p ~ l c1 . ~., .
palll Or traUllla LO the patIeIII IJ aYOIUGU. hllJU, II UCSIIeU, 1110 I~UIUC
LhaIIIIeI I IU (.an be ~GVQCjIGtCU OI IIGIUJ In Order
to facilitate its collapse prior to withdrawal.
As noted above, the guide channel membrane 140 is noncompliant both
longitudinally and radialfy. Thus,
it does not exhibit elastic characteristics which might cause the guide
channel 118 to bunch up or bind as the
instrument 112 is advanced therethrough. Moreover, the guide channel membrane
140 is malleable, meaning that
it tends ~o conform to the pressures and forces exerted upon it by ambient
conditions, including anatomy, tissue,
and other media. This feature advantageously tends to reduce resistance to
movement of the access device 100
and enhance patient comfort. On the other hand, in the absence of such ambient
forces, the membrane 140
maintains its position and configuration, having somewhat of a "memory" in
this regard and exhibiting patentency
characteristics. In other words, the membrane can be self-supporting, defining
an instrument lumen without the need
for internal wall support means.
A number of materials can achieve these advantages of the guide channel
membrane 140 of the present
invention. For example, inelastic polymers or other pleated, woven, or braided
materials can be utilized. Preferably,
however, highly orientated or cross-linked, noncompliant polymers can be
utilized as a guide channel membrane
Z5 material. Such materials tend to be thermoplastically settable, with glass
transition temperatures greater than room
temperature. in addition, such polymers are semicrystailine and deformabie in
the crystalline state.
These properties yield certain advantages in connection with the present
invention. For example, in order
to minimize profile, the guide channel membrane can be very thin, yet strong.
Because the material is detormabie
in its crystalline state, it may be folded, pleated, rolled, or otherwise
stored in combination with the introducer
without the loss of its advantageous mechanical properties, such as strength,
noncompliance, etc. In achieving this
storage position, the membrane can readily conform to the surface or space in
which it is placed. Because the
membrane is thermoplastically settable, once it is stored in this position,
the application of thermal energy will result
in the realignment of the crystalline structure so that the membrane retains
its storage position; however, it will be
understood that this set in the membrane storage position can also be achieved
by the application of mechanical
energy or chemicals (e.g., adhesives).
r= . .
CA 02244893 1998-07-27
~ -16-
Thus, it can be said that the membrane is "self-conformable," since it can
conform to a surface or space
and assume a given configuration, and then be self-retained in that
configuration. In addition, once it is desired to
remove the membrane from its stored configuration (e.g., in order to achieve
dilation), its deformability is again an
advantage. Besides thermal energy, mechanical, electrical, chemical, or
pneumatic energy can be applied to deploy
the guide channel. Again, because it is deformable in its crystalline state,
it will tend to become set or retained in
its deployed configuration.
One preferred polymeric example of the present guide channel membrane is
polyethylene terephthalate
("PET"), although other polymers are possible. For example, polybutyl
terephthalate may be utilized as a guide
channel 118, as well as nylon 6 or nylon 66. These materials, as well as
others, exhibit the advantages described
above.
-- in the case of PET, FIGURE 5 illustrates the noncompliant (stresslstrain
reiationship) of oriented PET as
compared with a typical elastomer. A PET curve 143 in the graph shows a shaded
region which depicts the behavior
of a highly-orientated PET which has been pre-stretched. These stress-strain
properties relate to a material which
has high strength and very little elongation when a load is exerted upon it.
Conversely, an elastomer behaves
different in this and all sections of its curve 145 on the graph by elongating
with little additional stress. Thus,
where careful precision in 'the configuration of the guide channel is
necessary, membrane material such as PET is
advantageous.
In addition, FIGURE 6 illustrates the relationships between tube diameters and
internal pressure for tubes
comprising PVC 147, polyolefin 149 and PET material 151. In the graphs in
FIGURE 6, plots are shown for a closed
vessel structure such as a balloon for various materials in which the outer
diameter measurement is platted versus
the internal pressure applied. In this example, the PET material 151
demonstrates very little distension with greater
internal pressure as a resort of its high strength and low elongation in
comparison to the polyolefin and PVC materials
149, 147 used for this example. Nevertheless, these and other materials can
provide suitable guide channel
membranes if treated properly during their manufacturing process. Thus, a
major component of the inelastic behavior
of PET and polyolefins is -the fact that their polymer chains in the material
have been highly orientated (PET) or
cross-linked ipolyolefins) with each other, providing greater strength and
resistance to strain. This high degree of
orientation, either by processing or secondary operations such as radiation
treatment or forming and axial stretching,
enables the nondistensible behavior of the present guide channel membrane.
Curved Guide Channels
FIGURES 7 and 8 illustrate another advantage of the present guide channel 118
relating to its ability to
actually guide a rigid or semi-rigid instrument being deployed through it
along a curved path. This advantage can
best. be described in light of the following background information. As shown
in FIGURE 1, a distal end 146 of the
introduces 100 of the present invention is curved slightly. This curvature
provides certain advantages, depending
upon the endoscopic surgical procedure being performed. In this case, the
introduces 100 of FIGURE 1 can be used
in performing a hysteroscopy, wherein an angle of curvature 8 in the range of
5-15° in the introduces 100 is
advantageous in navigating the uterine canal. This curvature, as noted above,
can also be used to gently move tissue
v,~ L~'t
A~~~;~DED
CA 02244893 1998-07-27
' -17- : .. . .
out of the way in order to achieve advancement of the endoscopelintroducer
combination 1101100 to the desired
location. With recent advancements in endoscopes, curvatures in these ranges,
and even up to 30°, can be achieved
without damage to the optical systems of the endoscopes.
However, another advantage of a curved introducer is illustrated in FIGURE 7.
As shown therein, an
endoscope 110 which provides vision out of the curved distal end 146 of an
introducer is able to sweep out a larger
field of vision upon rotation of said introducer 100. This is illustrated in
FIGURE 7 by a first and second position
(in phantom) of the distal end 146, rotated 180 degrees apart. This is a
particular advantage in the case of rigid
or semi-rigid endoscopes which do not have articulation means mounted at the
distal end. In order to achieve this
degree of curvature, as noted above in connection with FIGURES 3 and 4, the
endoscopic tube 132 can be
constructed from a strong and rigid stainless steel material which can be
preformed or bent to the desired curvature.
Whiie this material wiii provide the rigidity, strength, and protection for
the endoscope 110, it does not in and of
itself solve the problems of secondary channels formed in such curved surgical
access devices. Thus, secondary
channels of the prior art were constructed to be used only with straight
instruments or flexible instruments, such
as catheters.
The guide channel 118 of the present invention accommodates a rigid or semi-
rigid instrument which
experiences a curve along its shaft as it is inserted through the guide
channel. Thus, the guide channel 118 of the
present invention makes possible mother category of endoscopic surgical
procedures requiring a curved but rigid or
semi-rigid instrument. First, as noted above, the guide channel membrane 140
is constructed from an extremely
strong material in order to withstand the stresses on it caused by a biased
instrument mounted therein. Nonetheless,
it is important that the secondary instrument being advanced through the guide
channel 118 is provided with a
smooth and straight passage. Any slippage or lateral movement may cause damage
to the guide channel 118 andlor
discomfort to the patient.
Moreover, the guide channel 118 may be located at a number of different
circumferential locations with
respect to the main or endoscopic channel 122. Thus, as shown in FIGURE 7 in
phantom, the guide channel 11$
is located at the bottom of the main channel curvature. This longitudinal
location may be considered "inboard" with
respect to the curvature of the introducer 100. However, the guide channel 118
may also be positioned, as needed
or desirable far a particular procedure, "outboard" of the introducer
curvature (e.g.. on the upper portion of the
introducer 100 as oriented in accordance with FIGURE 7) or "sideboard" (e.g.,
on one or more lateral sides of the
introducer 100). At any of these various locations, the curved instrument will
exert, due to the bias or spring force
it causes as it bends, to apply a force on the outer sheath 134 of the main
channel 122 andlor the guide channel
118.
Thus, as illustrated in FIGURE 8, the guide channel 118 of the present
invention is provided with a guide
platform or other type of guide rail 148 in order to actually guide the
instrument 112 in its path along the guide
channel 118. Thus, even though the instrument may be bending and flexing, it
will tend to be retained in its path
along the guide platform 148, which acts as a rail or track for the instrument
to follow. As illustrated in FIGURE
8, in one preferred embodiment the guide rail 148 comprises the slit 136 in
the split sheath 134 of the main
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endoscopic channel 122. The longitudinal guiding capabilities of this slit 136
are also illustrated in FIGURE 4.
However, other guide platform configurations are possible, as illustrated in
FIGURE 9. FIGURE 9 depicts a D-shaped
main tube 232 which has a flattened area 150, 152 for instrument travel. This
flattened area could also contain
recesses or slots (not shown) to further facilitate directed insertion of the
instrument. In any particular grade channel
118 and guide rail 148 configuration, the guide channel membrane 140 is able
to assume a number of storage or
set positions, as described above.
Thus, as illustrated in FIGURE 9, the guide platform 148 may be flattened or
may be provided with lateral
walls 150, 152 in order to provide sure guidance for the curved instrument.
These lateral walls may also have
upward projections (not shown) so as to contain more securely the sides of the
instrument 112. Therefore, in
accordance with an important advantage of the present invention, the surgical
access device can be used to guide
an instrument along a specified path with respect to the main channel 122 so
that it achieves accurate placement
with respect to a specific location at the distal end of the access device
100.
Distal Portion
FIGURES 10 and 10a illustrate an alternate embodiment of a guide channel 218
of the present invention,
which is characterized by a perforated or serrated guide channel membrane 240.
As noted in FIGURES 10 and 10a,
the guide channel membrane 240 is provided with a reduced diameter in the
region of its distal tip 154. However,
in this region or at other regions along the longitudinal length of the guide
channel 218, the membrane 240 is
perforated or serrated in order to facilitate its release as a secondary
instrument 212 is advanced. Furthermore, the
perforations or slits can be such that the guide channel 218 opens up
completely in order to allow instrument access
to the lateral regions of the access device. Such perforated or serrated guide
channels 218 also provide other guide
channel storage options, as well as other advantages which will be apparent to
one of ordinary skill.
FIGURE 11 illustrates one embodiment of a distal tip 156 of the present
introducer 100. In this
embodiment, a tapered distal profile of the access device 100 facilitates the
insertion process; however, the extreme
distal edge is rounded or blunt in order to avoid damage to the tissue. Holes
158, 160 shown in the distal tip 156
are necessary to provide aspiration and avoid choking of irrigation media. In
this embodiment, the guide channel at
the distal tip 156, which is shown folded back on the outer surface 120 of the
split sheath 134, can be securely
sealed to the body of the introducer 100 by a heat seal process. Thus, the
guide channel 118 is sealed and is
impervious against contamination or distortion as the access device 100 is
introduced into the body. An alternative
embodiment of the distal tip 256 is shown in FIGURE 11a. The distal end of the
introducer can be shaped so as
to have an annular mound 159 at the distal tip of the guide channel 118 and
just proximal of the distal tip of the
access device 100. Likewise, this mound 159 can serve to protect the distal
end of the guide channel 118 against
contamination or damage as the access device 100 is introduced into the body
and navigated through its various
anatomy. .
Proximal Housing Portion
As explained above in connection with FIGURE 1, the proximal housing portion
104 of the present invention
surrounds the main endoscopic channel 122 and a merge channel 162 positioned
above it in FIGURE 12. The merge
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channel 162 allows an endoscope 110 or secondary instrument 112 to be inserted
through it for deployment through
the guide channel 118, shown in its predeployment position in FIGURE 12. The
merge channel 162 also allows a
proximal handle 113 of the instrument 112 to be offset or displaced with
respect to any endoscope or instrument
inserted in the main channel 12~ in order to facilitate use of the access
device 100 by the surgeon.
With reference to FIGURES 12 and 13, the proximal housing portion 104 of the
surgical access device 100
of the present invention can be described. FIGURE 12 is a partial cross-
sectional view of the side of the access
device 104, while FIGURE 13 is a cross-sectional view taken along lines 13-13
of FIGURE 13 in which is illustrated
the piggyback arrangement of the main or endoscopic channel 122 and the merge
channel 162 of the housing 104.
With reference to FIGURE 12, it will be seen that the merge channel 162
converges upon the main channel
122 at a shallow angle ~, gradually becoming asymptotic or tangential thereto.
The merge angle ~ should be
sufficient to allow a slight bending or curvature in the instrument being
inserted through the merge channel 162 and
into the guide channel 118; preferably, an angle ~p of about 4-30° is
satisfactory with 11 ° preferable.
At the extreme proximal end of the housing portion 104, there is shown an
inflow conduit 106 associated
with the main channel 122 and an outflow conduit 108 associated with the merge
channel 162. Depending upon
the procedure being performed, the inflow conduit 106 may be utilized to pass
distention or irrigation media down
the main channel 122 to the distal end of the access device 100. Having the
distension media run through the main
tube 132 and around the endoscope 110 also allows for fluid to travel across
the optics at the distal end of thz
endoscope 110 keeping this area free of blood and debris thereby improving
visualization. The outflow channel 108
can be used to provide aspiration or other evacuation of fluids. Also, of
course, the function of these conduits 106,
108 can be reversed or utilized in connection with multiple channels, as the
case necessitates. In each case, duckbill
valves 166, 168 are formed at the main or endoscopic port 14 and at the
instrument port 116 in order to prevent
the escape of fluids prior to insertion of the instruments into these
respective channels. Likewise, 0-ring structures
or washer elements prevent the escape of fluids around an endoscope or
instrument when inserted through the parts
114, 116. However, it will be understood that other types of valuing and
conduit mechanisms can be utilized in
connection with the present access device.
The cross-sectional view of FIGURE 13 also illustrates the association of the
guide channel membrane 140
with respect to the merge channel 162. That is, the membrane 140 is shown
extending through the slit or neck
136 in the split sheath 134 and completely around the merge channel 162.
Advantageously, the guide channel
membrane material can be heat formed onto both channels in order to provide
some rigidity and strength to the
proximal housing portion 104 of the access device 100. In fact, the membrane
140 can be extended proximally any
desired distance, as shown in FIGURE 12.
Method of Construction
FIGURE 14 is an exploded view of the present access device, illustrating a
method of construction of the
guide channel 118. Preferably,~the main tubing 132 is preformed into the
desired configuration, including any
curvature. The guide channel membrane 140, which may take the form of an
extruded tubing, as illustrated in
FIGURE 14, or other configuration, is then placed eccentrically around the
main tubing 132. The nylon split sheath
CA 02244893 1998-07-27
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134 is then mechanically expanded so as to surround the main tubinglmembrane
material, thereby capturing the
membrane 140 around the tubing 132. During this process the excess membrane
material is allowed to protrude
through the slit or neck 136 in the split sheath 134 and is then folded or
stored with respect to the access device
100 in accordance with various configurations discussed above. Covers or forms
are placed onto the folded
membranes and closely conform to the profile of the introducer 100. T hese
elements keep the membrane 140 in
close configuration prior to heat setting. Another method of forming a closely
fitting mold is to swell an elastomeric
tubing, such as silicone, with Freon. Prior to swelling, the silicone tubing
is of a smaller diameter than the introducer
100. Once swollen and enlarged, the silicone tubing is slid over the folded
membrane and introducer. When the
Freon evaporates, the silicone tubing will resume its pre-enlarged state
thereby creating a tightly fitting mold over
the membrane. After heat setting, the silicone tubing can be removed from the
introducer leaving the membrane in
a tight configuration with the introducer. in any case, a moderate amount of
heat is applied to tire access device
in order to thermoplastically set the guide channel membrane in its stored
position. In one preferred embodiment,
the PET material which comprises the guide channel membrane has a glass
transition temperature of 180°F (82.2°C).
Thus, the setting temperature used in this method of construction is
preferably about 160°F (71.1 °C). It will be
noted in this regard that sterilization of the system is achieved at about
140°F (60°C).
The present method is not limited to that illustrated in FIGURE 14 or
described above. A number of other
methods of construction will become apparent to those of ordinary skill. For
example, because of the thermoplastic
nature of the membrane material, heat forming, heat staking, or heat shrinking
can easily be employed in other
aspects of the construction method. Although most costly, adhesives or other
mechanical fasteners can be utilized.
Some adhesive systems can be effectively incorporated into the design of the
membrane material, main tube or slit
sheath by making these tubes as a co-extrusion with a secondary bonding
material as a composite within the tubing
material or body in which thermal bonding techniques can be employed. Heat-
activated or hot-melt adhesives. UU
cured adhesives, or pressure-sensitive adhesive systems can also be used to
facilitate attachment of the membrane
channel, such as the embodiment of FIGURES 3b and 3c, wherein the membrane is
mounted directly on the hypotube.
Such techniques can also be used for keeping the folded membrane tacked down
onto the surface of the main tube.
Method of Use
In accordance with the operation of the present invention, a method of use
comprises the steps of inserting
a surgical access device into an opening in the patient's body (this step
simultaneously comprising the insertion of
an endoscope or other visualization device or other instrument into the body
through said surgical access device or
sequentially inserting the visualization device through the surgical access
device and into the body after the surgical
device is already in position), storing in connection with the body of the
surgical access device one or more
secondary guide channels and setting said guide channel in its storage
position so as to provide a surgical access
device including the guide channel with the profile which is substantially
equivalent to the profile of the surgical
access device without the guide channel, which may include visualizing by
means of the endoscope the internal
anatomy or tissue of the patient, and releasing the guide channel from its
storage position with respect to the
surgical access device so as to permit insertion into the patient's body of a
secondary surgical instrument (or an
CA 02244893 1998-07-27 _
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endoscope or other visualization device), said releasing step being performed
simultaneously with the insertion of said
secondary instrument. The method may also comprise the steps of providing in
connection with the guide channel
a platform, rail, or track and guiding said secondary instrument through the
guide channel along said platform, rail,
or track. Clearly, because of the versatility of the surgical access device of
the present invention, a number of
methods of use are available.
Open Loop Introducer
An alternate embodiment of a distal tip 400 of an introducer for biopsies is
shown in FIGURES 15-17. As
shown, an open-loop device 402 is formed on a curved distal tip of a main
channel 404. Using an endoscope 406
positioned in the main channel 404, the device 402 may be manipulated by the
physician to collect a tissue
specimen. A hole 408 formed in the distal tip 400 provides a greater viewing
field for the endoscope 406 of the
tissue sampie area. A guide channei 4 t 0 is preferably provided in an
outboard configuration, and the device 402
has a curved length preferably extending past an inboard side 412 of the
introducer. Alternatively, the guide channel
410 may be formed on the inboard side (see FIGURE 15 in phantom). Further, the
length of the curved device 402
may be shorter so as not to extend past the inboard side 412 of the
introducer. During endoscopic surgery, as
discussed in greater detail below with regard to the method of use of the
present device, an aspiration tube 414
may be provided in the guide channel 410 as shown in FIGURES 15 and 17 for
removal of a tissue specimen
comprising either separate cells or a tissue section.
It should also be noted, with regard to the introducer of FIGURES 15-17, that
although the distal tip is
shown without particular shaping for sealing the guide channel and such as
described heretofore, it is understood
that other shapes for sealing at the distal tip of the introducer may be
readily incorporated.
In the open-loop device embodiment 402 being provided on the main channel of
tfie introducer, the
endoscope is inserted into the main channel and its field of vision is
enhanced by the hole 408 in the distal tip of
the main channel. An aspiration tube inserted through the guide channel
removes blood at the viewing area or may
be used to remove~the specimen. An inboard or outboard configuration of the
guide channel may be utilized.
Alternatively, the endoscope and aspiration tube may be switched, so that the
endoscope is in an inboard guide
channel, for example.
Laparoscopic Suraicallntroducer
In another embodiment of the present access device, a laparoscopic surgical
introducer is illustrated in
FIGURES 18-22. In this embodiment, the introducer is intended primarily for
laparoscopic procedures, such as
cholecystectomy, bipolar tubal sterilization, gamete intro-fallopian transfer
("GIFT"), directed biopsy, etc. However,
a wide variety of laparoscopic procedures may be performed with the
laparoscopic introducer of the present
invention.
FIGURES 18 and 18a illustrate the cross-sectional view of an alternative
embodiment of the access device
as taken along Line 3-3 in FIGURE 2. Due to the forces necessary to dilate the
guide channel 540, particularly
during a laparoscopic procedure, an alternate embodiment of the present
introducer comprises a guide channel 540
with a reinforcing device 528 positioned therein. As shown in FIGURES 18-19,
this reinforcing device 528 can
1 ~.L-i.L:c_L Ji-SLL.j
CA 02244893 1998-07-27.
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preferably take the form of a flat wire or other force distribution mechanism
so that the dilation forces do not cause
damage to the guide channel membrane. This reinforcement device 528 can also
facilitate insertion of the dilator
and other secondary instruments by providing a smooth riding surface.
Moreover, the reinforcement device 528, in
combination with other guide channel designs, can provide enhanced guiding and
tracking characteristics, as described
in more detail below in connection with FIGURES 20-21.
Preferably, the present reinforcement device 528 takes the form of a flat wire
having a thickness of
between about .001-.004 inches, and having a width of between about .040 inch
(10.16 mm) -.300 (76.2 mm) inch.
The flat wire is preferably constructed from stainless steel or other sturdy
material. The flat wire is positioned
longitudinally along the laparoscopic channel 522, but within the folds of the
guide channel 540. Thus, the dilator
or secondary instrument will ride along the reinforcement device 528. To
facilitate instrument insertion, the
reinforcement device extends proximally along the merge channel so that the
instrument rides below it as the
instrument emerges from the distal end of the merge channel and begins to
deploy the guide channel.
With reference to FIGURE 19, there is shown cross-sectional view of the
laparoscopic embodiment of the
present introducer through the insertion portion where the instrument 512 has
already advanced. In this case, the
secondary instrument 512 almost completely occupies a lumen 542 defined by the
guide channel 540 of the present
invention. As shown in FIGURE 19, the guide channel 540 is shown releasing its
predeployment position to allow
the secondary instrument 512 to easily pass along the guide channel 540 and
into the patient.
FIGURES 20-21 illustrate other features of the alternate embodiment of the
guide channel 540 including
its ability to securely guide the dilator 512 or instrument into a specific
location with the patient's body. Referring
to FIGURE 20, there is shown a cross-section of a nondilated guide channel 640
including a concave reinforcement
device 628. In this case, the internal flat wire which forms the reinforcement
device 628 is provided with a concave
depression or recess 629 which produces additional guidance for the dilator
andlor secondary instrument. This recess
629 serves to keep the instrument from "walking" off the laparoscopic channel
622 or otherwise deviating from its
longitudinal path along the insertion portion of the introducer.
As shown in FIGURE 21, the recess 629 formed in the flat wire 628 can, in
combination with the slit 636
in the split sheath 634, form a track far the secure guidance of the dilator
or instrument. Thus, in this embodiment
the instrument 612 is not likely to move laterally along its path, which
movement would cause pain and discomfort
to the patient and possible damage to the guide channel 640. Certainly, a wide
variety of guide channel tracking
designs are within the scope of the present invention. Moreover, guide rails
(not shown) in addition to the slit 636,
can be provided to provide even greater instrument guidance. These guide rails
may be provided with upward
projections toot shown) in order to provide even more secure guidance to the
sides of the instrument.
The guide channel 640 of this embodiment of the present invention accommodates
a rigid or semi-rigid
instrument which may be inserted through the guide channel. As noted above,
the guide channel membrane 620 is
' constructed from an extremely strong material in order to withstand the
stresses on it caused by a instrument
advancing therethrough. Nonetheless, it is important that the secondary
instrument being advanced through the guide
._. __
> ~ CA 02244893 1998-07-27. ..
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channel 640 be provided with a smooth and straight passage. Any slippage or
lateral movement may cause damage
to the guide channel 640 andlor discomfort to the patient.
Moreover, the guide channel 640 may be located at a number of different
circumferential locations with
respect to the main or endoscopic channel 622, any the main channel 622 may be
curved. Thus, the guide channel
640 may be located at the bottom of the main channel curvature, which could be
considered "inboard" with respect
to the curvature of the introduces. However, the guide channel 640 may also be
positioned, as needed or desirable
for a particular procedure, "outboard" of the introduces (e.g., on the upper
portion of the introduced, or "sideboard"
(e.g.. on one or more lateral sides of the introduces).
Therefore, in accordance with an important advantage of the present invention,
the surgical access device
can be used to guide an instrument along a specified path with respect to the
main channel 622 so that it achieves
. accurate placement with respect to a specific location at the distal end of
the access device.
FIGURE 22 illustrates another embodiment of a distal tip 708 of the present
introduces. In this embodiment,
the tip 708 is beveled so as to facilitate the insertion process; however, the
extreme distal tip may also he rounded
or blunt in order to avoid damage to internal tissue. The guide channel at the
distal tip 708, which is shown folded
back on the outer surface 735 of the split sheath 734, can be securely sealed
to the body of the introduces by a
heat seal process. Thus, the guide channel 520 is sealed and is impervious
against contamination or distortion as
the access device is introduced into the body. In another alternative
embodiment of the distal tip, the distal end
of the introduces may be shaped so as to have an annular mound at the distal
tip of the guide channel and just
proximal of the distal tip of the access device. Likewise, this mound can
serve to protect the distal end of the guide
channel against contamination or damage as the access device is introduced
into the body and navigated through
its various anatomy.
Hysteroscooic or Biopsy Introduces
If the surgeon notices a cyst, polyp, foreign body, lesion, or other
suspicious pathology, a therapeutic
procedure or biopsy can be accomplished concurrently with the initial
diagnostic procedure. Likewise, the present
invention advantageously avoids pre-dilation to accommodate a larger diameter
instrument in a planned, therapeutic
procedure, such as "GIFT."
A wide variety of secondary instruments, such as biopsy graspers, scissors,
lasers, electrodes, catheters,
etc. can be introduced into the guide channel and used in accordance with the
present invention. After choosing
an appropriate instrument in light of the initial diagnostic procedure, the
physician introduces the instrument into the
secondary port 116. In reference to FIGURE 23, for instance, in the case of
biopsying a potentially pathologic tissue
specimen 774, graspers 713 can be used. After introducing the distal end or
working portion 775 of the graspers
713 into the instrument port of the present device, the physician advances the
graspers 713 through the guide
channel 118. As the physician advances the secondary instrument through the
guide channel, the guide channel 118
will expand no more than is necessary to accommodate the cross-sectional
dimensions of the secondary instrument.
Accordingly, dilation of the cervix is kept to a minimum, which minimizes
patient discomfort.
._. ;_...~~.r,,
CA 02244893 2005-07-20
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The physician continues to advance the secondary instrument, such as the
graspers 713, through the guide
channel untg the working portion of the secondary instrument extends through
the distal end of the guide channel
as illustrated in FIGURE 23. At this point, using the hysteroscope, the
physician is able to simultaneously view the
graspers 713 and the targeted tissue 774, thereby enabling the physician to
further manipulate the secondary
instrument to treat the target tissue, perform a biopsy, remove a foreign
body, etc.
If a biopsy has been performed, the graspers 713 are w'tthdrawn from the guide
channel and the tissue
spec'Knen is sent to be examined by a pathologist. The graspers can then be
reintroduced into the instrument portal
and advanced through the guide channel to perform add'ttional biopsies, if
necessary.
After all biopsies have been performed, the hysteroscope and the access device
are withdrawn from the
70 patient. Because the guide channel provides minimal resistance to external
forces without an instrument in place,
the guide channel readily assumes a collapsed state in response to pressure
exerted by surrounding tissue as the
access device is w'tthdrawn from the patient, thereby minimaing patient
discomfort upon removal of the device.
In conclusion, the surgical access device of the present invention, including
the guide channel and method
for constructing same, represents a marked advancement in the art of
secondary, expandable endoscopic surgical
channels. Thus, tt should be understood that the scope of the present
invention is not to be fun-'rted by the
illustrations or foregoing description thereof, but rather by the appended
claims, and certain variations and
modifications of this invention will suggest themselves to one of ordinary
skill in the art.
