Note: Descriptions are shown in the official language in which they were submitted.
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Improved Distal End for Ligating Band Dispenser
Field of the Invention
The present invention relates generally to the field of tissue ligation,
and more particularly to an improved distal end for a device for dispensing
ligating
bands.
Background Information
Physicians have used elastic ligating bands to treat lesions, including
internal hemorrhoids and mucositis and for performing mechanical hemostasis.
The
object of such ligation is to position a ligating band, which is usually
elastic, over the
targeted lesion or blood vessel section by first stretching the band beyond
its
undeformed diameter and then drawing the tissue to be ligated within the band.
Thereafter the band is released so that it contracts, applying inward pressure
on the
section of tissue caught within the band. The effect of the inward pressure
applied
by the band is to stop all circulation through the targeted tissue, thereby
causing the
tissue to die. The body then sloughs off the dead tissue or the dead tissue
may be
aspirated into an endoscope or a similar device.
Previous ligating band dispensers allowed a user to dispense only a
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single ligating band at a time. That is, after a single ligating band was
dispensed, if a
user wanted to ligate another portion of tissue, the user would remove the
device
from the patient's body, load a new ligating band on the device and reinsert
the
device to the desired area within the patient's body.
United States Patent No. 5,398,844 to Zaslavsky et al. ("the Zaslavsky
patent"), describes a ligating band dispensing device including a
substantially
cylindrical support surface over which elastic ligating bands are stretched.
The
cylindrical support surface is typically attached to the distal end of an
endoscope
which is advanced into the body to a target area. A user then applies suction
through
the endoscope to draw the tissue to be ligated into the cylindrical support
surface and
releases a ligating band to contract around the tissue. While the device of
the
Zaslavsky patent allows a user to place several ligating bands at desired
locations
without removing the device from the patient's body to reload the ligating
bands, it
requires multiple pull strings to deploy the ligating bands. These pull
strings may
interfere with each other or become tangled. In addition, as the number of
ligating
bands included on the distal end of these devices has been increased, the
nuinber of
pull strings increases while the dispenser itself elongates. Accordingly, the
field of
vision from the endoscopes to which these devices are normally coupled has
been
correspondingly decreased.
n~m M of the Invention
R I
The present invention is directed to a supporting structure for a
ligating band dispensing device being adapted to be coupled to a distal end of
an
endoscope. The supporting structure comprises a substantially cylindrical
support
surface adapted to receive a plurality of ligating bands thereon, wherein the
support
surface includes a channel extending therethrough from a distal end to a
proximal
end. The supporting structure further includes a plurality of shallow slots
and deeper
slots disposed on the distal end for retaining a trigger string. The shallow
slots and
deeper slots may, for example, be arranged in an alternating fashion, and each
of the
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slots may be, for example, narrower than the trigger string to prevent the
trigger
string from prematurely exiting the slots.
The support surface may also include a plurality of axially extending
ridges to assist in the deployment of the ligating bands by preventing the
bands from
sliding along the trigger line and facilitating rolling of the bands along the
support
surface.
Brief Description of the Drawings
The present invention will be more readily understood through the
following detailed description, with reference to the accompanying drawings,
in
which:
Fig. I is a perspective view of a distal end of a ligating band
dispensing device according to a first embodiment of the present invention;
Fig. 2 is a cross-sectional view of the ligating band dispensing device
of Fig. 1, taken along line 4-4 of Fig. 1;
Fig. 3 is a cross-sectional view of a ligating dispensing device
according to a second embodiment of the present invention; and
Fig. 4 is a cross-sectional view of a ligating dispensing device
according to a third embodiment of the present invention.
Fig. 5 is a cross-sectional view of a ligating dispensing device
according to a fourth embodiment of the present invention.
Fig. 6 is an end view of the ligating dispensing device of Fig. 5.
Fig. 7 is a detailed view of a slot of the ligating dispensing device of
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Fig. 5.
Fig. 8 is a detailed view of a second slot of the ligating dispensing
device of Fig. 5.
Fig. 9 is a detailed cross-sectional view of an embodiment of a distal
end of the ligating dispensing device of Fig. 5.
Figs. 10 and 11 are detailed cross-sectional views of the slots of Figs.
7 and 8, respectively, taken along lines 10-10 and 11-11 of Fig. 6,
respectively.
Fig. 12 is a perspective view of the ligating dispensing device of Fig.
5.
Fig. 13 is a cross-sectional view of the ligating dispenser device of
Fig. 5, showing the provision of a trigger line through a ring in the device.
Fig. 14 is a side view of the ligating dispenser device of Fig. 5,
showing an exemplary arrangement of ligating bands and trigger line.
Fig. 15 is a side view of a ligating dispenser device illustrating the
forces affecting movement of a ligating band.
Fig. 16 is an expanded view of a highlighted portion of Fig. 15.
Fig. 17 is a perspective view of a further exemplary embodiment of a
ligating dispenser device according to the present invention.
Fig. 18 is a perspective view of a portion of the ligating dispenser
device of Fig. 17.
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Fig. 19 is a front view of the ligating dispenser device of Fig. 17.
Detailed Description of the InventiQn
As illustrated in Fig. 1, a device 1 according to a first embodiment of
the present invention includes a substantially cylindrical support surface 30
coupled
to an elastic ring 8. A central bore 3 (not shown in Fig. 1) which extends
through
the support surface 30 and the elastic ring 8, in operation, receives the
distal end of
an endoscope 6. A plurality (8 in this case) of ligating bands 4 are received
around
the support surface 30 with a trigger line 20 wrapping around each of the
ligating
bands 4 in a repeating pattern. The support surface 30 and the support surface
30' of
Fig. 3 for receiving 8 ligating bands 4 thereon will preferably be between .5
and .8
inches in length and may preferably be between .65 and .75 inches in length.
While
the support surface 30" of Fig. 4 may preferably be between .45 and .65 inches
in
length and is more preferably between .5 and .6 inches in length. Of course,
those
skilled in the art will understand that the length of the support surface may
need to
be varied depending on the thickness of the ligating bands (in a direction
distal to
proximal) received thereon. The ligating bands 4 of Fig. 3 are received on the
support surface 30 so that a distal-most band 4 is separated from a distal end
14 of
the support surface 30 by an area 15 which is, except for the trigger line 20,
substantially free from visual obstructions. The support surface 30 is
preferably
substantially transparent. However, those skilled in the art will understand
that at
least the area 15, which preferably extends .2 -.3" should be transparent.
The trigger line 20 extends from a proximal end accessible to a user,
through a lumen 22 in the endoscope 6 to pass through the central bore 3 and
out to
the support surface 30 via a first one of a plurality of grooves 24. The
trigger line 20
then extends across the support surface 2, passes over the distal-most of the
ligating
bands 4 and wraps underneath this ligating band 4 to extend back into the
first
groove 24. The trigger line 20 then loops under the distal end 14 of the
support
surface 30 and passes through a second groove 24 adjacent to the first groove,
passes
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under the distal-most band 4, wraps around this band 4 and passes under and
around
a second band immediately proximal to the distal-most band 4. The trigger line
20
continues over the second band 4 and passes back under the distal-most band 4
to
extend to the second groove 24, returning from the second groove 24 to wrap
over
and around the second band 4, under the third band 4, etc. This pattern is
repeated
until the trigger line 20 extends around each of the ligating bands 4 received
on the
support surface 30. Of course, the arrangement of the trigger line 20 may be
varied
substantially so long as it is arranged so that a user is permitted to release
each of the
plurality of ligating bands 4 one at a time at each of a corresponding
plurality of
locations within the patient. Thus, for example, a separate trigger line 20
may be
provided for each of the ligating bands 4 or a single line 20 may be divided
at some
point between the user and the support surface 30 into a plurality of
filaments each
of which is coupled to a respective ligating band 4.
The endoscope 6 extends past the juncture between the ring 8 and the
support surface 30 to a shoulder 10 formed at a portion of the central bore 3
within
the support surface 30. This shoulder 10 may preferably be located beneath one
of
the distal-most of the ligating bands 4 and is most preferably located so
that, prior to
releasing any ligating bands, the shoulder is beneath the third ligating band
(counting
distal to proximal) preferably between .35 and .5", and more preferably
approximately .38" from the distal end of the support surface 30. This
shoulder 10
prevents the endoscope 6 from moving past a distal-most position within the
central
bore 3, to create a substantially unobstructed space 18 extending from the
distal end
14 proximally to the distal end of the endoscope 6. This space 18, which is
dimensioned similarly to that of the support surface 2 described above, is
separated
at the shoulder 10 from an increased diameter endoscope receiving portion 31
of the
bore 3 which preferably has a diameter of between .4 and .5 inches depending
upon
the diameter of the endoscope 6 which is to be received therein. The space 18
provides an area into which tissue to be ligated may be drawn so that a
ligating band
4 released from the support surface 30 will encircle and grip the tissue to
the extent
necessary for the band 4 to be maintained in position on the tissue after the
tissue has
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been released. That is, the tissue is drawn into the space 18 by known means
such
as, for example suction or a gripping mechanism (not shown) provided via the
lumen
22. Thus, the placement of the endoscope 6 within the rigid support surface 30
and
the extension of the support surface 30 distally beyond the distal-most
ligating band
4 allow the space 18 to extend distally of the distal-most band 4.
As noted above, the distal end of the endoscope 6 includes an optical
device 16 and a light source 26 which allow a user to view the area adjacent
to the
distal end of the device 1. The placement of the endoscope 6 within the rigid
support surface 30 and the consequent placement of the tissue receiving space
18
distally toward the distal-most band 4 (or distally past all of the ligating
bands 4),
allows the field of vision of the optical device 16 (shown by the dotted lines
in Fig.
2) to be increased relative to that obtained with an endoscope 6 seated
proximal to
the juncture between the ring 8 and the support surface 30. Those skilled in
the art
will understand that an increase of nearly 2 to I over prior placement
positions of the
endoscope may be obtained with this arrangement. Of course, this increase of
the
field of vision is achieved only when the support surface 30 is formed of a
transparent material which may preferably be polycarbonate.
As described above, the elastic ring 8 of the support surface 30 grips
the endoscope 6 to prevent if from becoming separated from the support surface
30.
However, those skilled in the art will understand that in order to maintain a
proper fit
of the endoscope 6 within the rigid support surface 2, or to accommodate
larger
endoscopes 6, sizing the endoscope receiving portion 31 of the central bore 3
to
correspond to the diameter of the distal end of a particular endoscope 6 will
provide
a more secure and stable mating with the support surface 30.
In operation, a plurality of ligating bands 4 are placed on the support
surface 30 with the trigger line 20 threaded between the bands 4 as described
above.
Then an endoscope 6 is passed into the endoscope receiving portion 31 of the
central
bore 3 via an opening formed in the proximal end of the elastic ring 8 until a
distal
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end of the endoscope 6 contacts the shoulder 10 and the trigger line 20
extended
from the proximal end of the endoscope 6 through the central bore 3 to the
ligating
bands 4 (preferably via the lumen 22) . The endoscope 6 is then inserted into
a
patient and advanced, under visual observation (via optical device 16) until
the distal
end 14 of the support surface 30 is adjacent to a portion of tissue to be
ligated. The
user then draws the tissue into the space 18 by, for example, advancing a
gripping
device (not shown) through the lumen 22 and grasping the tissue, or by
applying
suction through the lumen 22. When the tissue is in a desired position within
the
space 18, a user draws the trigger line 20 proximally through the lumen 22
until the
distal-most ligating band 4 is released from the support surface 30 to ligate
the
tissue. As described in the Zaslavsky patent, the trigger mechanism of a
ligating
device incorporating a support surface according to the present invention will
preferably provide the user with a tactile indication that a band 4 has been
released.
Additional bands may be triggered at the same site if desired using the same
technique.
Thereafter, the user releases the tissue by withdrawing the gripping
device or stopping application of the vacuum pressure and then visually guides
the
endoscope 6 to a second location within the patient. When the support surface
30 is
located adjacent to a second portion of tissue to be ligated, the user repeats
the
process described above, releasing a second of the plurality of ligating bands
4. The
second of the plurality of ligating bands 4 is preferably, after release of
the first of
the plurality of ligating bands 4, the distal-most ligating band 4 received on
the
support surface. The remaining ligating bands 4 may then be released one at a
time,
starting with the distal-most remaining ligating band 4 and progressing to the
proximal-most band 4. Thus, the device I allows a user to ligate 8 or more
portions
of tissue without removing the device 1 from the patient while providing the
user
with improved control of the endoscope 6 resulting from the expanded visual
field.
The support surface 30" of Fig. 4 differs from the support surfaces 30
and 30' only in that it is shorter as it is intended to receive only 5
ligating bands
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thereon. Of course, those skilled in the art will understand that increased
numbers of
ligating bands 4 may be received on a support surface as described simply by
lengthening the endoscope receiving portion 31 of support surface to the
extent that
the increase in length of the support surface does not result in excessive
irritation to
the patient or to difficulties in inserting the device into a body lumen.
Figures 5-14 illustrate a fourth embodiment of the present invention.
As with the above embodiments, the ligating dispenser device of Figures 5-12
includes a substantially cylindrical support surface 130 having a central,
axially-
extending bore 103 therethrough. While being substantially cylindrical, the
support
surface 130 may be slightly tapered in the distal direction, as shown in
Figure 5. The
support surface 130 includes, for example, a shoulder 110 on its interior
surface,
against which an endoscope 6 may abut. An endoscope 6 place into the bore 103
will enter a proximal portion 131 of the bore 103 but will be prevented from
moving
further distally into a distal portion 118 of the bore 103 by the shoulder
110.
The support surface 130 has a distal end 114, which includes, for
example, a plurality of slots 124a and 124b for receiving and retaining a
trigger line
(not shown in Figures 5-12). The slots 124a are, for example, relatively
shallow
20 in depth compared to the deeper slots 124b, as shown in Figures 7 and 8.
The slots
124a and 124b are arranged in an alternating fashion with respect to one
another, so
that as a trigger line 20 is looped through the slots 124a and 124b and wound
around
one or more bands 4, it alternatingly passes through each type of slot. In a
further
exemplary embodiment, the shallow slot 124a may retain the "lead string" for
each
band 4 (the proximal of the two segments of the trigger line 20 that together
form a
loop the band 4), while the deeper slot 124b may retain the "trailing string"
for the
band 4. A ring 160 may serve as a guide for trigger line 20 as the trigger
line
extends initially from the endoscope to the distal end 114 of the support
surface 130,
as shown in Figure 13
In a preferred embodiment, the total number of slots 124a and 124b is
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equal to the number of segments of the trigger line 20 that will be retained
in the
slots 124a and 124b. In other words, the trigger line 20 passes, for example,
through
each slot 124a or 124b only once. Accordingly, a minimum number of required
slots
may be determined as a function of the number of bands placed on the dispenser
and
the number of loops of the trigger line 20 which will be wrapped around each
band.
For example, if the trigger line 20 passes around each band 4 once and if
eight bands
are present, then there could be sixteen total slots present, eight shallow
slots 124a
and eight deeper slots 124b. Of course, other configurations are possible. In
addition, regardless of the number of segments of the trigger line 20 formed
by the
arrangement of the trigger line 20 and the bands 4, additional (unused) slots
may be
present.
The trigger line configuration is illustrated in Fig. 14. As can be
seen, after the trigger line 20 is looped around a first one of a plurality of
the bands
4, it may be extend back under the band to be looped around a second one of
the
bands 4. Once looped around the pair of the bands 4, the trigger line 20 may
then
return to the distal end 114 of the support surface 130. At the distal end
114, trigger
line 20 may wind through a shallow slot 124a and a deeper slot 124b as
described
above, and then return proximally to loop around the second band 4 and a third
of
the bands 4. This configuration of the trigger line 20 allows the ligating
bands 4 to
be completely released from the support surface 130. For example, when the
trigger
line 20 in Fig. 14 pulls the distal most band 4a from the distal end 114, the
trigger
line loop 20a, 20b pulls through the center of the band 4a completely freeing
the
band 4a from the trigger line 20. The trigger line portion 20b is then
positioned for
the deployment of the second band 4b.
The combination of shallow slots 124a and deeper slots 124b
increases deployment reliability while minimizing the possibility of the
trigger line
20 prematurely leaving the slots 124a and 124b. In particular, the shallow
slot 124a
holds the trigger line 20 closer to the distal end 114 of the support surface
130, so
that as the band 4 is pulled the trigger line 20 can draw it closer to the
distal end 114,
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increasing deployment reliability. At the same time, the deeper slot 124b may
retain
the trigger line 20 further from the distal end 114, decreasing the
possibility of the
trigger line 20 leaving the slots. As shown in Figures 10 and 11, the shallow
slots
124a extend, for example, only partially into a beveled portion 150 at the
distal end
114 of the cylindrical housing 130, while the deeper slots 124b extend, for
example,
fully into the beveled portion 150. The beveled portion 150 encourages, for
example, proper deployment of the bands 4 by decreasing the likelihood that a
band
4 will be "stranded" at the distal end 114. A band 4 pulled onto the beveled
portion
150 will tend to deploy, even without further pulling by the trigger line 20,
via the
elastic forces within the band 4.
In a preferred embodiment, the slots 124a and 124b are also, for
example, narrower than the trigger line 20. If the width of the slots 124a and
124b is
smaller than the diameter of the trigger line 20, then the trigger line 20 is
more
firmly retained in the slots 124a and 124b. This arrangement further minimizes
the
chance of the trigger line 20 coming out of the slots 124a and 124b before the
associated band 4 deploys, which might leave the band 4 near the distal rim
114 of
the support surface 130 and hamper the deployment of further bands 4.
In an exemplary embodiment, the support surface 130 may be
approximately .6 to.8 inches in length and approximately .4 to .6 inches in
outer
diameter. The bore 103 may be approximately .3 to .5 inches in diameter, and
the
proximal portion 131 of the bore 103 may have a diameter of approximately .35
to
.55 inches in diameter (so that the entire bore may include portions having
diameters
ranging from approximately .3 to .55 inches). The shallow slots 124a may be
approximately .01 to .02 inches in depth and approximately .006 to .01 inches
in
width, and the deeper slots 124b may be approximately .02 to .04 inches in
depth
and approximately .006 to .01 inches in width. The slots 124a and 124b may be
arranged around the distal end 114 with an angular spacing of approximately 6
to 10
degrees between each slot. These dimensions are exemplary and should not be
construed as a limitation on the present invention.
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In a further exemplary embodiment, the support surface 130 may be
approximately .7 inches in length and approximately .5 inches in outer
diameter.
The bore 103 may be approximately .4 inches in diameter, and the proximal
portion
131 of the bore 103 may have a diameter of approximately .45 inches in
diameter.
The shallow slots 124a may be approximately .015 inches in depth and
approximately .008 inches in width, and the deeper slots 124b may be
approximately
.03 inches in depth and approximately .008 inches in width. The slots 124a and
124b may be arranged around the distal end 114 with an angular spacing of
approximately 8 degrees between each slot. Again, these dimensions are
exemplary
and should not be construed as a limitation on the present invention.
Figures 15-19 illustrate another exemplary embodiment of a support
surface 130 according to the present invention. In this embodiment, the
support
surface 130 generally includes, for example, a plurality of raised ridges 170
to assist
in the deployment of ligating bands 4. Figures 15 and 16 illustrate the forces
involved in the deployment of a ligating band 4, Figure 16 being an expanded
view
of the highlighted portion of Figure 15. In any design in which the bands 4
are
pulled towards the distal end 114 of the support surface 130, reliable band
deployment is facilitated by the bands rolling rather than sliding across the
support
surface 130. The rolling action is caused, for example, by the trigger line 20
pulling
over the top of the band 4 and by friction between the band 4 and the support
surface
130. Rolling is initiated, for example, at the point in which the trigger line
20
contacts the band 4, and propagates around the band circumference. This
rolling
causes the band 4 to move distally.
A potential problem is created when the band 4 slides instead of rolls.
If the band 4 slides across the support surface 130, it tends to push the
trigger line
120 ahead of it. The trigger line 120 may then come out of one or more slots
124 in
the distal rim, leaving the band 4 with no effective trigger line 120. The
trigger line
120 itself often exacerbates this problem, because it provides the bands 4
with a
relatively low-friction surface, increasing the chance of sliding. Also, with
sliding
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motion, there is less of a tendency for the band 4 to move at the point of the
support
surface 130 opposite the trigger line 120. This is particularly true if the
bands 4
undergo heating from, for example, a typical sterilization cycle.
An exemplary embodiment of a support surface 130 according to the
present invention includes, for example, a plurality of primary ridges 170 and
at least
one secondary ridge 172 to facilitate rolling of the bands 4. As shown in
Figures 17-
19, the primary ridges 170 may be disposed in the vicinity of the slots 124.
In an
exemplary arrangement, the primary ridges 170 may be arranged so that a pair
of
slots 124 are disposed between each adjacent pair of primary ridges 170. If
the
support surface 130 also includes shallow slots 124a and deeper slots 124b as
described above, then one of each type of slot may be disposed, for example,
between each corresponding pair of primary ridges 170.
The primary ridges 170 are preferably thick enough so that the bands
4 are maintained remote of the trigger line 20. In this manner, bands 4 are
unable to
slide along or push trigger line 120. In a further exemplary embodiment, the
primary
ridges 170 include a frictional surface on their outer face (the face
contacting the
bands 4). The frictional surface may include, for example, a plurality or
transverse
grooves or a sawtooth profile. Other friction-inducing features may also be
provided
in conjunction with or alternative to these exemplary features. The frictional
surface
increases the tendency of the bands 4 to roll rather than slide, increasing
deployment
reliability.
The exemplary support surface 130 also includes, for example, at
least one axially extending secondary ridge 172. In the embodiment of Figures
17-
19, for example, a pair of secondary ridges 172 are provided. Secondary ridges
172
reduce, for example, the contact area between the bands 4 and the support
surface
130, thereby reducing the tendency of the bands 4 to stick to the support
surface 130.
In addition, secondary ridges 172 also allow lubricant, which is often applied
to the
support surface 130 to aid insertion into the patient, under the bands 4,
further
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assisting propagation. The secondary ridges 172 are preferably disposed, for
example, substantially diametrically opposite any primary ridges 170 (if
present),
meaning simply that the secondary ridges 172 are preferable disposed, in
relation to
the primary ridges 170, on the opposite side of the circumference of the
support
surface 130. This exemplary configuration is illustrated in Figures 17 and 19.
The support surface 130 has been described with respect to several
exemplary embodiments. However, the present invention should not be limited to
the particular embodiments described herein, even where particular features
have not
been designated as exemplary. For example, primary ridges 170 and secondary
ridges 172 could be formed around the entire circumference of the support
surface
130, essentially forming a series of ridges that span the circumference of the
support
surface 130. In addition, there are many other modifications of the disclosed
embodiments which will be apparent to those of skill in the art. It is
understood that
these modifications are within the teaching of the present invention which is
to be
limited only by the claims appended hereto.
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