AU2003234481B2 - Ligating band dispenser - Google Patents

Description

LIGATING BAND DISPENSER

FIELD OF THE INVENTION

[0001] 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

[0002] 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.

[0003] Some previous ligating band dispensers allowed a user to dispense only a

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.

[0004] U.S. Patent No. 5,398,844 to Zaslavsky et al. ("the Zaslavsky '844

patent"), which is expressly incorporated by reference herein, 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 '844 patent allows a user to place several ligating bands at

desired locations without removing the device from the patient's body to reload ligating

bands, it requires multiple pull strings to deploy the ligating bands. These pull strings

may interfere with each other, may become tangled, or may take up excessive room in the

endoscope working channel, thereby preventing the use of catheter-type accessory

devices. In addition, as the number of ligating bands included on the distal end of these

devices is increased, the number 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.

[0005] ^"U.S. Patent No. 5,853,416 to Tolkoff ("the Tolkoff '416 patent") and U.S.

Patent No. 6,059,798 ("the Tolkoff '798 patent"), both of which are expressly

incorporated by reference herein, describe a distal end for a ligating band dispenser

wherein a plurality of ligating bands can be actuated sequentially by the same trigger line.

In addition, the bands can be located at a certain distance away from the distal end of the

device, and all or part of the cylindrical support surface may be transparent for

visualization. [0006] U.S. Patent No. 5,913,865 to Fortier et al. ("the Fortier '865 patent"),

which is also expressly incorporated by reference herein, also describes a distal end for a

ligating band dispenser that also allows a plurality of ligating bands to be actuated

sequentially by the same trigger line. The supporting structure as shown in the

embodiment of Figures 5-14 of the Fortier '865 patent includes a plurality of slots in the

distal end of the device that are arranged so that the trigger line need only pass through

each slot once. This helps prevent neighboring passes of the trigger line from becoming

twisted or tangled with one another. In addition, the Fortier '865 patent describes that the

slots can have alternating depths, such that alternating shallow slots and deeper slots are

disposed on the distal end for retaining the trigger line. With such an arrangement, the

lead part of the trigger line may be positioned in the shallower of two neighboring slots,

thus insuring that the lead part of the trigger line is closer to the distal rim of the device.

This increases deployment reliability. The deeper slot helps prevent the trigger line from

coming off prematurely. In addition, each of the slots may be narrower than the trigger

line, which also helps prevent the trigger line from prematurely exiting the slots.

[0007] As described in the Fortier '865 patent, and as shown in the embodiment

of Figures 17-19 of that patent, the support surface also may 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. Having the bands roll, instead of slide, along the support surface promotes

deployment of the bands. If a band slides along the support surface, it may not deploy.

The axially extending ridges are described as having a frictional surface, which may include, for example, a plurality of transverse grooves or a sawtooth profile. (Col. 8,

lines 2-4).

[0008] While the entire disclosure of the Fortier '865 patent is expressly

incorporated by reference herein, specific reference is made to the embodiment of Figures

5-14 and the embodiment of Figures 17-19, as discussed above. Like the rest of the

Fortier '865 patent, the description and illustration of these embodiments, including the

means for deployment of the bands, is expressly incorporated herein by reference.

[0009] Physicians, when using a device such as one of the above-mentioned

devices, often apply a lubricant to the device, to aid in intubation. While the lubricant

aids in intubation, it also reduces the friction between the ligating bands and the support

surface. The reduced friction may cause the ligating bands to slide instead of roll along

e support surfac , and hence may reduce the probability of a successful bund

deployment.

SUMMARY OF THE INVENTION

[0010] The present invention is directed toward providing an improved distal end

for a ligating band dispenser, wherein the device has an improved transverse groove or

ridge profile that promotes rolling of the bands instead of sliding.

[0011] In one embodiment, the ligating bands and the transverse grooves or

ridges on the support surface are dimensioned such that the width of the bands when

stretched on the support surface is substantially the same as the pitch of the transverse

grooves or ridges on the support surface. In another embodiment, the ligating bands and the transverse grooves or ridges on the support surface are dimensioned such that the

width of the bands when stretched on the support surface is less than the pitch of the

transverse grooves or ridges on the support surface. Having the width of the bands when

stretched on the support surface be substantially the same as or less than the pitch of the

transverse grooves or ridges on the support surface allows the bands to fit within the

grooves. This helps insure that the bands are sufficiently held back by the ridge crests to

induce a rolling action.

[0012] In another aspect of the invention, in addition to having the pitch of the

transverse grooves or ridges be substantially the same as or greater than the width of the

stretched bands, the transverse grooves or ridges may also be dimensioned such that the

height of the ridge crests is sufficiently high to insure that the bands are sufficiently held

back by the ridge crests to induce a rolling action.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The present invention will be more readily understood through the

following detailed description, with reference to the accompanying drawings, in which:

FIG. 1 is a side view of a prior art ligating dispenser device illustrating the

forces affecting movement of a ligating band;

FIG. 2 is an expanded view of a highlighted portion of FIG. 1;

FIG. 3 is a perspective view of a prior art ligating dispenser device;

FIG. 4 is a perspective view of a portion of the prior art ligating dispenser

device of FIG. 3; FIG. 5 is a front view of the prior art ligating dispenser device of FIG. 3;

FIG. 6 is an enlarged view of a portion of a ridge profile of a prior art

ligating dispenser device;

FIG. 7 is a cross-sectional view of a distal end of a ligating band dispenser

device;

FIG. 8 is an enlarged view of a portion of an improved transverse ridge

profile of a ligating dispenser device according to the invention; and

FIG. 9 shows the portion of the transverse ridge profile of the ligating

dispenser device of FIG. 8, with ligating bands in place.

DETAILED DESCRIPTION OF THE INVENTION

[0014] FIGS. 1 and 2 illustrate the forces involved in the deployment of a ligating

band 4, FIG. 2 being an expanded view of the highlighted portion of FIG. 1. In any

design in which the bands 4 are pulled towards the distal end 114 of a 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.

[0015] Potential problems are created when the band 4 slides instead of rolls. If

the band 4 slides across the support surface 130, that portion of the band 4 at the trigger line 20 may reach the distal rim of the support surface, thereby allowing the trigger line

20 to come free from one or more slots 124 in the distal rim (slots 124 are shown in FIG.

3), prior to motion being initiated in the band 4 at a position diametrically opposite the

trigger line 20. This leaves the band 4 with no effective trigger line 20. Also, if the band

4 slides across the support surface 130, it tends to push the trigger line 20 ahead of it.

This too may cause the trigger line 20 to come out of the slots, leaving the band 4 with no

effective trigger line 20. The trigger line 20 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 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 20. This is particularly true

if the bands 4 undergo heating from, for example, a typical sterilization cycle.

[0016] As shown in FIG. 3. an example o^r a prior art suppo-1 surface 130 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 FIGS. 3-5, 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 alternating

shallow slots and deeper slots, then one of each type of slot may be disposed, for

example, between each corresponding pair of primary ridges 170. Alternatively, all of

the slots 124 may have the same depth.

[0017] 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 20.

[0018] The support surface 130 in FIGS. 3-5 also includes, for example, at least

one axially extending secondary ridge 172. A pair of secondary ridges 172 are shown.

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 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 configuration is illustrated in FIGS. 3 and 5. The primary ridges 170 and secondary

ridges 172 could alternatively 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.

[0019] Some examples of dimensions for the device are as follows. The support

surface may have, for example, a length of approximately 0.6 to 0.8 inches and an outer

diameter of approximately 0.4 to 0.6 inches. The channel may have a diameter of

approximately 0.3 to 0.55 inches. The slots may have a depth of approximately 0.01 to

0.04 inches and a width of approximately 0.006 to 0.01 inches. If slots of alternating

depths are used, the shallow slots may have a depth of approximately 0.01 to 0.02 inches,

and the deeper slots may have a depth of approximately 0.02 to 0.04 inches, each with a width of approximately 0.006 to 0.01 inches. The slots may be arranged around the distal

end with an angular spacing of approximately 6 to 10 degrees between adjacent slots.

[0020] The Fortier '865 patent describes that the primary ridges 170 may 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.

The frictional surface increases the tendency of the bands 4 to roll rather than slide,

increasing deployment reliability. The Fortier '865 patent, however, provides no

description of the size, spacing or number of grooves.

[0021] FIG. 6 shows the groove profile of the first commercial embodiment of the

Fortier '865 patent having transverse grooves, the prior art SPEEDBAND™

SUPERNIEW ligating device (Boston Scientific Corp.). As shown in FIG. 6, that device

had a groove pitch PI of approximately 0.039" and groove depth D! « .f approximately

0.015". This device was used with ligating bands that had a relaxed (off housing) outer

diameter (OD) of 0.229", a relaxed inner diameter (ID) of 0.075", a relaxed wall height

(i.e., the distance between the ID and OD) of 0.077", and a relaxed width (measured in

the direction along an axis passing through the center of the band) of 0.077". Because the

width was substantially the same as the wall height, the cross-section geometry of these

bands was substantially square. When stretched onto the housing as shown in FIG. 6, the

width of the bands was reduced to approximately 0.050". Since the groove pitch was

approximately 0.039", the width of the bands was thus approximately 28% greater than

the groove pitch, making the width of the bands substantially greater than the groove

pitch. [0022] In another version of the prior art SPEEDBAND™ SUPERVIEW ligating

device (Boston Scientific Corp.) using the housing as shown in FIG. 6, ligating bands

were used having a relaxed (off housing) outer diameter (OD) of 0.259". a relaxed inner

diameter (ID) of 0.075", a relaxed wall height (i.e., the distance between the ID and OD)

of 0.092", and a relaxed width (measured in the direction along an axis passing through

the center of the band) of 0.077". Because the width was smaller than the wall height, the

cross-section geometry of these bands was substantially rectangular. When stretched

onto the housing as shown in FIG. 6, the width was again reduced to approximately

0.050". Again, since the groove pitch was approximately 0.039", the width of the bands

was approximately 28% greater than the groove pitch, making the width of the bands

substantially greater than the groove pitch.

[0023] The present invention is directed to an improved distal end for a ligating

band dispenser, wherein the device has a transverse groove or ridge profile that promotes

rolling of the bands. One example of an embodiment according to the present invention

is illustrated in FIG. 8. As shown in FIG. 8, that device had a groove pitch P2 of

approximately 0.060" and groove depth D2 of approximately 0.018". This ligating bands

for use with this embodiment of the device according to the invention are shown stretched

on the housing in FIG. 9. These ligating bands have a relaxed (off housing) outer

diameter (OD) of 0.245", a relaxed inner diameter (ID) of 0.075", a relaxed wall height

(i.e., the distance between the ID and OD) of 0.085", and a relaxed width (measured in

the direction along an axis passing through the center of the band) of 0.085". Because the

width is substantially the same as the wall height, the cross-section geometry of these bands is substantially square. When stretched onto the housing as shown in FIG. 9, the

width W2 of the bands is reduced to approximately 0.060". Since the groove pitch is also

approximately 0.060", the width of the bands in this embodiment when stretched on the

support surface is substantially the same as the pitch of the transverse grooves or ridges

on the support surface. Having the width of the bands when stretched on the support

surface be substantially the same as the pitch of the transverse grooves or ridges on the

support surface allows the bands to fit within the grooves, as shown in FIG. 9. As will be

appreciated by persons of ordinary skill in the art, this configuration helps insure that the

bands are sufficiently held back by the ridge crests to induce a rolling action when the

trigger line pulls on the bands.

[0024] In another embodiment of the invention, the ligating bands and the

transverse grooves or ridges on the support surface may dimensioned such that the width

of the bands when stretched on the support surface is less than the pitch of the transverse

grooves or ridges on the support surface. Having the width of the bands when stretched

on the support surface be less than the pitch of the transverse grooves or ridges on the

support surface also allows the bands to fit within the grooves, which again helps insure

that the bands are sufficiently held back by the ridge crests to induce a rolling action.

[0025] In another aspect of the invention, in addition to having the pitch of the

transverse grooves or ridges be substantially the same as or greater than the width of the

stretched bands, the transverse grooves or ridges may also be dimensioned such that the

height of the ridge crests is sufficiently high to insure that the bands are sufficiently held

back by the ridge crests to induce a rolling action. Thus, for example, the groove depth D2, which also corresponds to the height of the ridge crests, may be approximately

0.018", as shown in FIG. 8.

[0026] The transverse groove or ridge profile as described herein may be used on

any suitable ligating band dispensing device, for example a ligating band dispensing

device similar to that shown or described in the Fortier '865 patent or as described or

depicted herein. Persons of ordinary skill in the art will appreciate that modifications

may be made to the above-described embodiments without departing from the scope of

the invention. For example, other dimensions may be chosen for the ligating bands or the

groove or ridge pitch or height, so long as the principles described herein are still

followed. The full scope of protection sought for the invention is defined in the appended

claims.

Claims (20)

What is claimed is:

1. A ligating band dispensing device comprising:

a supporting structure comprising a substantially cylindrical support

surface adapted to receive a plurality of ligating bands and a trigger line on an

outer surface thereof, the support surface having a channel extending axially

therethrough from a distal end to a proximal end, the support surface including at

least one axially extending primary ridge disposed on the outer surface, said at

least one primary ridge maintaining the plurality of ligating bands in a position

remote from the trigger line, wherein said at least one primary ridge includes a

plurality of transverse grooves on an outer face; and

a plurality of ligating bands stretched onto he support surface,

wherein the ligating bands and the transverse grooves on the support

surface are dimensioned such that the width of the bands when stretched on the

support surface is substantially the same as the pitch of the transverse grooves on

the support surface.

2. The ligating band dispensing device according to claim 1 , wherein transverse

ridges are located between adjacent transverse grooves, resulting in a plurality of

transverse ridges, and wherein the height of the transverse ridges is dimensioned

to insure that the bands are sufficiently held back by the transverse ridges to

induce a rolling action.

3. The ligating band dispenser device according to claim 2, wherein the height of the

transverse ridges is approximately 0.018 inches.

4. The ligating band dispensing device according to claim 1, wherein the pitch of the

transverse grooves on the support surface is approximately 0.060 inches.

5. The ligating band dispensing device according to claim 1, wherein the width of

the bands when stretched on the support surface is approximately 0.060 inches.

6. The ligating band dispensing device according to claim 1, wherein the support

surface has an outer diameter of approximately 0.4 to 0.6 inches.

7. The ligating band dispensing device according to claim 1, wherein the support

surface further includes a plurality of slots disposed on the distal end for retaining

the trigger line, and wherein the support surface includes a total number of the

slots so that, when the ligating bands and the trigger line are arranged on the .

support surface, the trigger line passes through each slot at most once.

8. The ligating band dispensing device according to claim 1, comprising a plurality

of shallow slots and deeper slots, wherein the plurality of shallow slots and deeper

slots are grouped in slot pairs, each of the slot pairs including one of the shallow

slots and an adjacent one of the deeper slots, and wherein each of the slot pairs is disposed between a corresponding pair of the primary ridges.

9. The supporting structure according to claim 1, the outer surface of the support

surface further including at least one axially extending secondary ridge, the at

least one secondary ridge maintaining the ligating bands remote from the support

surface.

10. A ligating band dispensing device comprising:

a supporting structure comprising a substantially cylindrical support

surface adapted to receive a plurality of ligating bands and a trigger line on an

outer surface thereof, the support surface having a channel extending axially

therethrough from a distal end to a proximal end, the '•αpport surface including at

least one axially extending primary ridge disposed on the outer surface, said at

least one primary ridge maintaining the plurality of ligating bands in a position

remote from the trigger line, wherein said at least one primary ridge includes a

plurality of transverse grooves on an outer face; and

a plurality of ligating bands stretched onto the support surface;

wherein the ligating bands and the transverse grooves on the support

surface are dimensioned such that the width of the bands when stretched on the

support surface is less than the pitch of the transverse grooves on the support

surface.

11. The ligating band dispensing device according to claim 10, wherein transverse

ridges are located between adjacent transverse grooves, resulting in a plurality of

transverse ridges, and wherein the height of the transverse ridges is dimensioned

to insure that the bands are sufficiently held back by the transverse ridges to

induce a rolling action.

12. The ligating band dispenser device according to claim 11, wherein the height of

the transverse ridges is 0.018 inches.

13. The ligating band dispensing device according to claim 10, wherein the pitch of

the transverse grooves on the support surface is approximately 0.060 inches.

14. The ligating band dispensing device according to claim 10, wherein the width of

the bands when stretched on the support surface is approximately 0.060 inches.

15. The ligating band dispensing device according to claim 10, wherein the support

surface has an outer diameter of approximately 0.4 to 0.6 inches.

16. The ligating band dispensing device according to claim 10, wherein the support

surface further includes a plurality of slots disposed on the distal end for retaining

the trigger line, and wherein the support surface includes a total number of the

slots so that, when the ligating bands and the trigger line are arranged on the support surface, the trigger line passes through each slot at most once.

17. The ligating band dispensing device according to claim 10, comprising a plurality

of shallow slots and deeper slots, wherein the plurality of shallow slots and deeper

slots are grouped in slot pairs, each of the slot pairs including one of the shallow

slots and an adjacent one of the deeper slots, and wherein each of the slot pairs is

disposed between a corresponding pair of the primary ridges.

18. The supporting structure according to claim 10, the outer surface of the support

surface further including at least one axially extending secondary ridge, the at

least one secondary ridge maintaining the ligating bands remote from the support

surface.

19. A method of deploying ligating bands comprising:

providing a supporting structure comprising a substantially cylindrical

support surface adapted to receive a plurality of ligating bands and a trigger line

on an outer surface thereof, the support surface having a channel extending axially

therethrough from a distal end to a proximal end, the support surface including at

least one axially extending primary ridge disposed on the outer surface, said at

least one primary ridge maintaining the plurality of ligating bands in a position

remote from the trigger line, wherein said at least one primary ridge includes a

plurality of transverse grooves on an outer face; providing a plurality of ligatmg bands stretched onto the support surface,

wherein the ligating bands and the transverse grooves on the support surface are

dimensioned such that the width of the bands when stretched on the support

surface is substantially the same as or less than the pitch of the transverse grooves

on the support surface so that the ligating bands fit within the transverse grooves;

and

actuating the trigger line so as to induce a rolling action in said ligating

bands toward the distal end of the supporting structure.

20. The method of deploying ligating bands according to claim 19, wherein transverse

ridges are located between adjacent transverse grooves, resulting in a plurality of

transverse ridges, and wherein the height of the transverse ridges is dimensioned

to insure that the bands are sufficiently held back by the transverse ridges to

induce a rolling action.