Surgery – Endoscope – With protective sheath
Reexamination Certificate
2002-01-04
2004-05-25
Flanagan, Beverly M. (Department: 3739)
Surgery
Endoscope
With protective sheath
C600S121000, C600S104000
Reexamination Certificate
active
06740030
ABSTRACT:
TECHNICAL FIELD
The present invention is directed toward endoscopic apparatus and methods, and more specifically, to endoscope assemblies having working channels with reduced bending and stretching resistance.
BACKGROUND OF THE INVENTION
Endoscopes are widely used for a variety of medical procedures. To improve their performance, endoscopes have been optimized in various ways to best accomplish their purpose. Examples of specialized endoscopes include angioscopes, colonoscopes, bronchoscopes, and arthroscopes.
One of the medical procedures that may be performed using an endoscope is obtaining a biopsy sample.
FIG. 1
shows a conventional endoscope assembly
10
used for obtaining a biopsy sample. The endoscope assembly
10
includes an endoscope
20
having an elongated insertion tube
22
. The insertion tube
22
may be rigid, partially flexible, or entirely flexible The insertion tube
22
includes a distal portion
24
that may be inserted into a body cavity of a patient (not shown), and a working end
26
.
The endoscope
20
includes a headpiece
28
that remains external to the patient during a medical procedure. In the embodiment shown in
FIG. 1
, the headpiece
28
includes an eyepiece
30
for viewing the scene through a viewing lens
31
at the working end
26
of the insertion tube
22
, a pair of articulation control knobs
32
for manipulating the position of the distal portion
24
of the insertion tube
22
, and a pair of fluid control actuators
34
for controlling the flow of fluids through tubes
36
to (or from) the working end
26
. Endoscopes
20
of the type generally shown in
FIG. 1
are described more fully, for example, in U.S. Pat. No. 5,931,833 issued to Silverstein, U.S. Pat. No. 5,483,951 issued to Frassica and Ailinger, and U.S. Pat. No. 4,714,075 issued to Krauter and Vivenzio, which patents are incorporated herein by reference. Representative commercially-available endoscopes include, for example, video or fiberoptically-equipped sigmoidoscopes, bronchoscopes, nasopharyngo-laryngoscopes, colonoscopes, and gastroscopes.
As further shown in
FIG. 1
, the endoscope assembly
10
includes a sheath
40
that encapsulates the insertion tube
22
to prevent at least part of the insertion tube
22
from being soiled during the medical procedure. The sheath
40
may be flexible to allow unrestricted bending of the flexible portion of the insertion tube
22
, or may be relatively rigid. In the depicted embodiment, the sheath
40
includes an enlarged fitting portion
42
that fits over an engagement portion
44
of the headpiece
28
, and a working channel
46
having a proximal end
48
that projects outwardly from the sheath
40
proximate the headpiece
28
.
FIG. 2
is an enlarged isometric view of the working end
26
of the endoscope assembly
10
of FIG.
1
. As shown in
FIG. 2
, the sheath
40
surrounds the insertion tube
22
of the endoscope
20
, and the working channel
46
extends along an outer surface of the insertion tube
22
. The working channel
46
terminates in an open distal end
49
at the working end
26
of the insertion tube
22
. A medical instrument
50
, including a biopsy sampling device
52
, extends through the working channel
46
(see
FIG. 1
) and projects from the open distal end
49
of the working channel
46
. Sheaths of the type shown in
FIGS. 1 and 2
are described more fully, for example, in U.S. Pat. No. 5,025,778 issued to Silverstein et al., U.S. Pat. No. 5,483,951 issued to Frassica et al., and U.S. Pat. No. 5,827,177 issued to Oneda et al.
During a medical procedure, the medical instrument
50
is inserted into the proximal end
48
of the working channel
46
and slid through the working channel
46
until the biopsy sampling device
52
emerges from the open distal end
49
at the working end
26
. Through the eyepiece
30
, the physician observes the biopsy sampling device
52
through the viewing lens
31
and manipulates the medical instrument
50
into the desired position and collects the desired sample. After a biopsy sample is obtained, the biopsy sampling device
52
containing the biopsy sample may be withdrawn through the working channel
46
, or alternately, the entire insertion tube
22
may be withdrawn from the patient's body with the biopsy sampling device
52
remaining in position near the working end
26
.
Although desirable results have been achieved using the conventional devices described above, some drawbacks do exist. For example, during a medical procedure, the flexible insertion tube
22
is generally manipulated into various bending positions using the articulation control knobs
32
. It is therefore desirable for such endoscope assemblies that the sheath
40
, including the working channel
46
, be fabricated of a flexible material to allow for bending and articulation of the insertion tube
22
. Furthermore, it may be desirable to axially stretch the sheath and working channel when positioned on the insertion tube
22
to maintain a tight engagement between an enclosed, transparent end cap of the sheath and the viewing lens
31
of the insertion tube
22
, as described more fully, for example, in co-pending, commonly-owned U.S. patent application Ser. No. 09/235,355.
For these reasons, sheaths are commonly constructed of a flexible elastomeric material. A variety of known flexible materials are used for this purpose. Generally speaking, however, such known flexible materials have high coefficients of friction that inhibit the movement of medical instruments through the working channel. In some situations, such as at a sharp bending corner along the insertion tube, the medical instrument may be unable to progress through the working channel, or may even become stuck, necessitating the removal of the insertion tube.
To reduce the coefficient of friction of the internal surface of the working channel, a variety of techniques have been employed. One approach has been to line the working channel with a relatively-hard corrugated material having a low coefficient of friction, such as materials sold under the trademark TEFLON®. Because the relatively-hard corrugated material has a lower coefficient of friction than the flexible material of the working channel, the medical instrument moves more easily through the working channel, and the corrugations allow the necessary bending and axial stretching of the working channel. Unfortunately, the lining of relatively-hard corrugated material greatly increases the thickness of the wall of the working channel, and thus, the overall diameter of the endoscope assembly. Thus, the sheath having a working channel lined with a relatively-hard corrugated material may increase the discomfort or trauma experienced by the patient, or may not be practical for some medical procedures due to size constraints within the patient's body. Also, the cost of manufacturing the working channel lined with the relatively-hard corrugated material is undesirably high. Finally, although the corrugated channel does stretch axially, it does not do so easily.
SUMMARY OF THE INVENTION
The present invention is directed to endoscope assemblies having working channels with reduced bending and stretching resistance. In one embodiment, an endoscope assembly includes a sheath having a body portion adapted to at least partially encapsulate an endoscopic insertion tube, and a working channel attached to the body portion and extending along at least a portion of the body portion. The working channel has a cut disposed therein, the cut being at least partially transverse to a longitudinal axis of the working channel. The working channel is separable along at least a portion of the cut when the working channel is subjected to an axial tension force.
In an alternate embodiment, the working channel has a gap disposed therein, the gap being at least partially transverse to a longitudinal axis of the working channel. The gap is adapted to widen along at least a portion thereof when the working channel is subjected to an axial tension force.
In another embodiment, the working
Martone Stephen
Oneda Katsumi
Dorsey & Whitney LLP
Flanagan Beverly M.
Vision - Sciences, Inc.
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