Ligating band dispenser

A ligating band dispenser for attachment to the distal end of a ligating device having proximal and distal ends with a lumen extending therebetween and being adapted for supporting a plurality of ligating bands includes a support for attachment to the distal end of the ligating device and for carrying the plurality of ligating bands and having a passage communicating with the lumen; and a dispenser including a first displacement element looped about each of the bands in series attached to the support and extending through the passage and lumen whereby proximal motion of the operator element from the proximal end of the ligating device transfers individually the most distal ligating band off the distal end of the support.

FIELD OF INVENTION 
This invention relates to a ligating band dispenser for attachment to the 
distal end of an endoscopic device having proximal and distal ends with a 
lumen extending therebetween and being adapted for supporting a plurality 
of ligating bands, and more particularly to such a dispenser which employs 
a single displacement element to dispense a plurality of bands 
sequentially and individually. 
BACKGROUND OF INVENTION 
It is well known that one can treat various types of lesions including 
hemorrhoids and esophageal varices by ligation. The object of ligation is 
to position an elastic cord, or ligating band, around the lesion to stop 
circulation through the tissue and allow the tissue to die whereupon the 
body sloughs off the dead tissue. One instrument for facilitating the 
placement of a single ligating band or set of bands includes, at its 
distal end, a ligating band dispenser comprising two rigid, concentric 
tubes. The tubes can slide with respect to each other under the control of 
a trigger mechanism at the proximal end of the instrument. A rigid 
endoscope having internal passages forming a suction path and a light path 
interconnect the trigger mechanism and dispenser. The dispenser inner tube 
can be loaded with a set of one or more elastic rings or ligating bands. A 
separate stopper bar attaches to the instrument to prevent premature 
dispensing. When the instrument is located proximate a lesion, a surgeon 
removes the stopper bar and applies suction to draw tissue into the hollow 
passage at the distal end of the dispenser. Pulling on the trigger 
retracts the inner tube. The larger diameter of the outer tube engages the 
ligating band so the band cannot displace with the inner tube. As the 
inner tube is withdrawn from the ligating band, it slides off the inner 
tube and elastically contracts onto the tissue. 
Another instrument includes a ligating band dispenser with an inner tube 
that moves with respect to an outer tube to dispense a ligating band. This 
dispenser is oriented at right angles to the rigid endoscope and includes 
a structure for moving the inner tube of the dispenser in this 
configuration. 
A third similar dispenser approach includes an inner tube that moves 
axially with respect to an outer tube at the distal end of the instrument. 
The outer tube attaches axially onto the distal end of the endoscope. An 
operating mechanism in the form of a pull wire with a weighted handle 
maintains tension on the inner tube so that it does not displace axially 
outwardly while the instrument is being positioned. For some applications 
it is suggested that the endoscope structure be inserted through an 
overtube to prevent premature dispensing. Suction can be applied to draw 
tissue into the central aperture of the dispenser formed by the inner 
tube. Then a surgeon pulls the handle and retracts the inner tube axially 
past the distal end of the outer tube to force the ligating band of the 
instrument onto the tissue. 
Each of the foregoing instruments dispenses a single ligating band or a 
single set of ligating bands at a single location. None suggests 
dispensing ligating bands at discrete locations. These instruments 
apparently would have to rely on a surgeon's sense of touch in order to 
displace the inner tube by an incremental distance corresponding to the 
thickness of a stretched ligating band to deposit a plurality of bands at 
different sites. That would be very difficult to accomplish. 
Indeed, when it was desired to deposit ligating bands at different sites, 
the common practice was to load and dispense one band and to withdraw the 
entire instrument from the patient and load a new ligating band onto the 
inner tube each time. Loading ligating bands onto an instrument requires 
special tools and can be time consuming, particularly if the special 
tooling must be available to install each ligating band individually while 
the instrument is withdrawn. Each of these instruments requires some 
structure, such as special stoppers or overtubes, for preventing the 
premature dispensing of the ligating band. Consequently, none of these 
instruments is readily adaptable for dispensing ligating bands at 
different sites without withdrawing the instrument after each individual 
site is ligated. 
Another device, a multiple ligating band dispenser for ligating instruments 
includes interfitted inner and outer structures that support a plurality 
of ligating bands at axially spaced locations. Retraction of the inner 
structure dispenses one ligating band. Extension of the inner structure 
advances the remaining ligating bands distally, axially so the next 
retraction dispenses another ligating band. This ligating band dispenser 
overcomes some but not all of the undesirable characteristics of 
single-band dispensers. For example, prior art single-band dispensers can 
eject a ligating band inadvertently if, during placement, tissue at the 
distal end of the dispenser, rather than the physician, moves the distal 
edge of the movable tube. The multiple band dispenser overcomes this 
problem by using a spring to bias the movable tube to a distal position. 
However, the use of the spring increases the force that must be used 
during the dispensing operation. Also, the distal edge of the movable tube 
is the most distal part of the dispenser. During placement, this edge 
engages the lesion to form a vacuum seal thereby allowing the lesion to be 
withdrawn into the lumen of the endoscope. When the movable tube moves 
proximally during the dispensing operation, the vacuum seal can break 
thereby enabling the lesion to pull away from the dispenser. 
In one attempt at dispensing a plurality of ligating bands individually and 
sequentially, a support, coaxially attached to the distal end of an 
endoscope, carries the plurality of ligating bands at axially spaced 
positions along an exterior surface. There are two concentric tubes with 
grooves inside the outer tube. The elastic ligating bands are positioned 
between the tubes and within the grooves so that rotation of the outer 
tube by means of a screw mechanism advances all the bands. This allows the 
bands to be sequentially advanced off the end of the dispenser. In another 
embodiment there are two concentric tubes, the inner being rigid and the 
outer being a flexible fabric. The bands are arranged on the outer surface 
of the fabric tube separated by small protrusions forming grooves on which 
the bands rest. The distal edge of the fabric is folded over the distal 
edge of the rigid tube so that it may be pulled proximally inside the 
rigid tube. A cable is provided to pull the fabric tube inward, causing 
the bands to be sequentially released from the end of the device. Both 
advance all the ligating bands simultaneously. Due to the strong elastic 
force applied by the bands on the housing and the friction between the 
bands and the housing, moving all bands at the same time requires 
significant pull force. In addition, moving all the bands simultaneously 
increases the likelihood of inadvertently firing two or more bands 
simultaneously. 
Another attempt for dispensing a plurality of ligating bands individually 
and sequentially uses a support, coaxially attached to the distal end of 
an endoscope, and carries the plurality of ligating bands at axially 
spaced positions along an exterior surface. One or more displacement 
filaments are looped around each band; each filament then loops over the 
distal edge of the dispenser where it is secured. The other end of each 
filament runs beneath the band, over the distal edge of the dispenser and 
joins with a pull wire which exits the proximal end of the endoscope. When 
a physician moves the pull wire a certain distance proximally, the 
filaments sequentially advance each band off the distal edge of the 
dispenser, releasing the securing means as the band slides off the distal 
end of the dispenser. Various means are described to enable a single pull 
wire to sequentially advance multiple sets of filaments. 
This approach overcomes some of the drawbacks of earlier devices. In 
treating lesions of the esophagus or other difficult to approach 
structures, it is desirable to have a sufficient number of ligating bands 
to assure completion of the procedure without the necessity of removal and 
reinsertion of the endoscope. Although this device can deliver multiple 
bands, it has some drawbacks. Each band has one or a pair of filaments 
used for advancing the band over the distal edge of the structure and onto 
the tissue. A complex attachment harness is used to assure that the series 
of loops of filaments is displaced sequentially to release only one band 
at a time from the distal end. Additionally, when the number of bands 
increases, the assembly labor and manufacturing complexity of assembly of 
the device becomes significant, and increases considerably with increasing 
numbers of bands. In addition, the displacement filaments all run though 
the working channel of the endoscope, and the small diameter of this 
channel limits the number of filaments. Additionally the filaments may 
limit the suction and obstruct other functions such as delivery of fluid 
or other devices through the working channel. The large number of 
filaments significantly obstructs drawing of tissue into the ligating 
structure and limits visibility through the end of the device. 
SUMMARY OF INVENTION 
It is therefore an object of this invention to provide a ligating band 
dispenser for dispensing plural ligating bands, individually and 
sequentially at one or many different sites. 
It is a further object of this invention to provide such a ligating band 
dispenser for dispensing plural ligating bands individually without the 
need to remove the dispenser after each band dispensing. 
It is a further object of this invention to provide such a ligating band 
dispenser which is usable with a variety of ligating devices, endoscopes 
and similar structures. 
It is a further object of this invention to provide such a ligating band 
dispenser which is reliable, easy to use and reduces the likelihood that 
the vacuum seal will be broken between the distal end of the dispenser and 
lesion being treated. 
It is a further object of this invention to provide such a ligating band 
dispenser which reduces to a minimum the number of operator elements 
necessarily present in the working passage of the dispenser. 
It is a further object of this invention to provide such a ligating band 
dispenser which dispenses plural ligating bands at different locations and 
allows for passage of other devices, such as sclerotherapy injection 
needles, through the working channel. 
It is a further object of this invention to provide such a ligating band 
dispenser which dispenses plural ligating bands at different locations, 
where operation required to dispense the bands does not significantly 
limit the space or visibility through the working channel which forms the 
entrance chamber for the tissue drawn into the dispenser in preparation 
for ligation. 
It is a further object of this invention to provide such a ligating band 
dispenser which is simple to make and use. 
It is a further object of this invention to provide such a ligating band 
dispenser which is particularly useful for esophageal varices. 
The invention results from the realization that an improved, simpler 
ligating band dispenser can be achieved using a single displacement 
element by looping the element around each band seriatim and attaching it 
to the band support means so that a single displacement element actuated 
by a single operation can dispense all of a plurality of ligating bands 
individually, separately and sequentially. 
This invention features a ligating band dispenser for attachment to the 
distal end of a ligating device having proximal and distal ends with a 
lumen extending therebetween and being adapted for supporting a plurality 
of ligating bands. There are support means for attachment to the distal 
end of the ligating device and for carrying the plurality of ligating 
bands. The support means has a passage communicating with the lumen of the 
ligating device. There are dispensing means including a first displacement 
element looped about each of the bands in series. The displacement element 
is attached to the support means and extends through the passage and lumen 
of the ligating device. An operator element extending from the 
displacement element through the lumen and accessible at the proximal end 
of the lumen whereby proximal motion of the first displacement element 
from the proximal end of the ligating device transfers the most distal 
ligating band off the distal end of the support means. 
In a preferred embodiment the support means may include a like plurality of 
notches and the displacement element may extend through a corresponding 
notch at least once over, around and under the associated band and return 
to a notch. For all but the last band the displacement element may extend 
from the returned to notch to the next notch and then under, around and 
over the associated band. Dispensing means may include a second 
displacement element looped about each of the bands in series and spaced 
about the bands from the first displacement element. The first 
displacement element may include stop means for arresting movement of the 
distal end of the displacement element during band dispensing. The support 
means may include limiter means for preventing withdrawal of the first 
displacement element from the support means after the last band is 
dispensed. The dispensing means may include an operator element extending 
from the displacement element through the lumen of the ligating device and 
accessible at the proximal end of the lumen. Slack may be provided in at 
least one of the loops of the displacement element about the bands. The 
support means may include a distal edge portion and the displacement 
element may extend distally of the distal edge portion, loop around a 
corresponding ligating band and releasably attach to the support means at 
the distal edge portion. The support means may include tubular body means 
having an exterior cylindrical surface for carrying the ligating bands and 
having a proximal shoulder portion and may include connector means for 
connecting the shoulder portion to the proximal end of the ligating 
device. The dispensing means may include a second displacement element, 
each displacement being looped about a separate set of at least one band. 
DISCLOSURE OF PREFERRED EMBODIMENT 
Other objects, features and advantages will occur to those skilled in the 
art from the following description of a preferred embodiment and the 
accompanying drawings, in which: 
FIG. 1 is a side elevational view with portions broken away of a ligating 
band dispenser according to this invention mounted on the distal end of a 
ligating device such as an endoscope showing the special threading pattern 
of the dispensing element; 
FIG. 2 is a view similar to FIG. 1 with the first ligating band displaced 
toward the distal end of the dispenser; 
FIG. 3 is a view similar to FIGS. 1 and 2 with the first ligating band 
clear of the distal edge of the dispenser about to be freed from the 
displacement element and encircle hemorrhoidal tissue or an esophageal 
varix; 
FIG. 4 is a view similar to FIGS. 1-3 showing limiter means for preventing 
complete withdrawal of the displacement element from the dispenser; 
FIG. 5 is a view taken along lines 5--5 of FIG. 4; 
FIG. 6 is a view similar to FIG. 1 showing purposely introduced slack in 
the loops of the displacement element about some of the ligating bands; 
and 
FIG. 7 is a diagrammatic view showing the bands operated in two different 
groups by two different displacement elements.

There is shown in FIG. 1 a ligating band dispenser 10 according to this 
invention attached to the distal end 12 of a ligating device such as 
endoscope 14. Dispenser 10 includes a support 16 which engages flexible 
connector 18 on shoulder 20. The other portion 22 of connector 18 attaches 
to the distal end 12 of endoscope 14. Passage 24 in support 16 
communicates with lumen 26 in endoscope 14. In accordance with this 
invention, a plurality of ligating bands 30, 32, 34, 36 and 38 are 
stretched onto support 16. The entire assembly of ligating band dispenser 
10 and endoscope 14 are typically circularly symmetrical about 
longitudinal axis 40 and are circular in cross section, although this is 
not a necessary limitation of the invention. 
Displacement element 42 extends through passage 24, then lumen 26, and then 
outwardly over the distal edge 44 of support 16 through notch 46. From 
there displacement element 42 loops over at 48, around at 50, and under at 
52 the first ligating band 30 and then returns to that same notch 46, 
extends at 54 along the inside edge and exits radially outwardly once 
again and exits once again through notch 56, whereupon it moves under 58, 
around 60 and over 62 the first ligating band 30, then under 64 it moves 
under 58, around 60 and over 62 the first ligating band 30, then under 64 
ligating band 30, over 66 the second ligating band 32, around 68 ligating 
band 32, and under it 70, back to notch 58. The paths of subsequent loops 
74, 76, 78, 80, 82 and 88 and their engagement with notches 90, 92 and 94 
can be easily traced in FIG. 1. A knot 96 or device of similar function 
can be placed at the end at 98 of displacement element 42 to prevent it 
from being pulled through retaining hole 122. Displacement element 42 can 
be connected to operator element 100 which extends all the way to the 
proximal end 102 of endoscope 14. Displacement element 42 and operator 
element 100 may in fact be one and the same thread, filament, wire or 
string. 
As displacement element 42 and/or operator element 100 is pulled to the 
right in FIG. 2, the first band 30 is moved and/or rolled to the left 
toward distal end 44 of support 16 of dispenser 10. Continued pulling on 
element 42 and/or 100 causes band 30 to slide free of distal end 44 of 
support 16 of dispenser 10. At the moment, depicted in FIG. 3, the loop 
110 of the displacement element 42, being free of notches 46 and 56, will 
unwrap from around band 30, causing the next pull on element 42 to begin 
movement of the next band 32 to the left. At this time band 30 collapses 
about the hemorrhoidal tissue which has been vacuum-drawn into the end of 
support 16 by means of a vacuum supplied through lumen 26 in a 
conventional fashion. 
The movement of element 42 to the right in FIG. 3 draws up the slack so 
that further pulling on elements 42 or 100 will begin moving band 32 to 
the left in the same way as band 30. A limiter 120, FIG. 4, is provided 
within support 16 to catch the knot 98 or other device of similar function 
so that even after the last band 38 is dispensed element 42 cannot be 
completely withdrawn from dispenser 10. This serves to keep dispenser 10 
tethered to the distal end 12 of endoscope 14 so that dispenser 10 cannot 
be inadvertently lost inside the patient. Limiter 120 employs a hole 122 
which is smaller than knot 98 so that knot 98 cannot be pulled through it. 
The structure of limiter 120 and the hole 122 can be seen more clearly in 
FIG. 5. 
Slack is preferably introduced as slack loops 130, 132, FIG. 6, so that 
each band 30-38 can be advanced at intervals without moving one or more 
additional bands simultaneously. This is done for control and to reduce 
the friction or drag encountered. The movement of two, three or additional 
bands increases the resistance such that a much stronger force must be 
applied to element 42 or 100 and such force could pose a danger to the 
patient or a threat of inadvertent shifting of the dispenser at a critical 
moment such as when the band is released to encircle the varix or tissue 
or cause release of multiple bands simultaneously. 
The location of each band is progressively further from the distal edge of 
the dispenser. Therefore, the travel from resting position to release for 
each successive band increases. The handle at the proximal end of the 
endoscope for releasing the bands is designed for simplicity for the user 
so that the handle advances about one inch per band release. It is 
desirable that the advance for releasing each band be the same so that the 
user can rely on the uniformity of dispensing. But, since there is a 
different travel per band, in order to have a uniform advancement, a 
varying length of slack is used to make up the difference in travel 
between bands. 
The length of string that is woven around the distal band is considerably 
shorter than that woven around the proximal band. Therefore, if there was 
no slack in the string between the first and second band, when the string 
is pulled one inch, two bands would deploy instead of one. Chart I below 
shows the distance and the slack needed: 
CHART I 
______________________________________ 
Length of string Total length per 
woven around band 
Length of slack 
band 
______________________________________ 
Band 1 .2 inch .8 inch 1.0 inch 
Band 2 .4 inch .6 inch 1.0 inch 
Band 3 .6 inch .4 inch 1.0 inch 
Band 4 .8 inch .2 inch 1.0 inch 
Band 5 1.0 inch 0 inches 1.0 inch 
______________________________________ 
Chart II shows the slack for eight bands: 
CHART II 
______________________________________ 
Length of string Total length per 
woven around band 
Length of slack 
band 
______________________________________ 
Band 1 .2 inch 1.6 inches 1.8 inches 
Band 2 .4 inch 1.4 inches 1.8 inch 
Band 3 .6 inch 1.2 inches 1.8 inch 
Band 4 .8 inch 1.0 inch 1.8 inch 
Band 5 1.0 inch .6 inch 1.8 inch 
Band 6 1.2 inches .4 inch 1.8 inches 
Band 7 1.4 inches .2 inch 1.8 inches 
Band 8 1.6 inches 0 inches 1.8 inches 
______________________________________ 
A length of 1.8 inch of advance per band is not desirable and would be 
unacceptable to the user. To solve this problem, the eight bands are split 
into two groups of four. Then the slack would appear as in Chart III: 
CHART III 
______________________________________ 
Length of string Total length 
woven around band 
Length of slack 
per band 
______________________________________ 
First String 
Band 1 .2 inch .8 inch 1.0 inch 
Band 2 .4 inch .6 inch 1.0 inch 
Band 3 .6 inch .4 inch 1.0 inch 
Band 4 .8 inch .2 inch 1.0 inch 
Second String 
Band 5 .2 inch .8 inch 1.0 inch 
Band 6 .4 inch .6 inch 1.0 inch 
Band 7 .6 inch .4 inch 1.0 inch 
Band 8 .8 inch .2 inch 1.0 inch 
______________________________________ 
The use of two different groups of four bands each is shown in FIG. 7 where 
support 16 carries two groups of ligating bands, 140 and 142. Displacement 
element 100 engages the distal series of bands 140. After the bands 140 
are deployed, displacement element 110 engages the proximal series of 
bands 142. After the bands 142 are deployed, the knot 108 lodges into the 
limiter 120. 
Although specific features of this invention are shown in some drawings and 
not others, this is for convenience only as each feature may be combined 
with any or all of the other features in accordance with the invention. 
Other embodiments will occur to those skilled in the art and are within the 
following claims: