FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
& The Patent Rules, 2003
COMPLETE SPECIFICATION
1.TITLE OF THE INVENTION:
INSULATION OF AN ELECTROSURGICAL INSTRUMENT
2.APPLICANT:
Name: CMR SURGICAL LIMITED
Nationality: United Kingdom
Address: 1 Evolution Business Park, Milton Road, Cambridge, Cambridgeshire, CB24 9NG,
United Kingdom.
3.PREAMBLE TO THE DESCRIPTION:
The following specification particularly describes the invention and the manner in which it is
to be performed:
1
CMR01-131252PC
Insulation of an Electrosurgical Instrument
Field of the invention
5
This invention relates to the insulation of an electrosurgical instrument, and in particular to a
device for applying an insulating sleeve to an electrosurgical instrument.
Background of the invention
10
Electrosurgery is a type of surgery that has been developed to replace traditional surgical
methods and uses a high frequency electrical current to generate heat that provides a means
to cut, dissect, fulgurate, ablate or shrink organic tissue. This method provides advantages
such as increased cutting precision and minimised blood loss. Electrosurgery may be
15 performed using one of two modalities; either a monopolar or bipolar modality. In monopolar
electrosurgery the tissue is targeted using a singular probe electrode, whereas bipolar
electrosurgery uses a bipolar device such as a pair of forceps.
Monopolar electrosurgery requires a firing drive cable that conducts an electrical current
20 from an electrical supply to an end effector. In known monopolar electrosurgical systems, the
end effector is supplied with current by a firing drive cable that conducts current from an
electrical source to the end effector. In order for the end effector to be energised they must
be electrically insulated from the other components located at the distal end of the
electrosurgical equipment. One solution for insulating the end effector from the other
25 electrical components is to encase them in an over-mould constructed from an electrically
insulating material such as PEEK. A disadvantage associated with this over-mould is that it
restricts the range of motion of the end effector. This limits the ability of the end effector to
perform cold-cutting, in which it is actuated in the absence of any heat applied by the
electrical current. In addition to this, design of the over-mould results in a high manufacturing
2
complexity due to the alignment of the metallic parts of the instrument shaft over the plastic
moulded parts, which results in an increase in part-to-part variability.
There is a need for a new mechanism for electrically insulating an electrosurgical instrument
5 that overcomes the abovementioned disadvantages.
Summary of the invention
According to a first aspect, there is provided a device for applying an insulating sleeve to an
10 electrosurgical instrument, the device comprising a housing, the housing comprising: a first
end; a second end; a hollow channel extending from the first end to the second end, the
channel being configured to receive an electrosurgical instrument comprising an end effector
connected to a shaft by a distal articulation; a support structure internal to the housing; the
support structure being configured to: support an insulating sleeve such that the insulating
15 sleeve surrounds the electrosurgical instrument when the electrosurgical instrument is
received by the channel; and when the electrosurgical instrument is advanced through the
channel from the first end to the second end, release the insulating sleeve onto the
electrosurgical instrument.
20 The channel may comprise a first portion and a second portion, wherein the first portion is
narrower than the second portion.
The proximal end of the support structure may be located on a ledge that separates the first
portion of the channel from the second portion of the channel.
25
The first portion of the channel may be circular in cross section, and the first portion may
further comprise an opening located on the ledge of the support structure.
3
The support structure may comprise a plurality of protrusions surrounding the opening, the
plurality of protrusions extending distally along an axis that is parallel to an axis along which
the channel extends.
5 The plurality of protrusions may comprise a first set of protrusions and a second set of
protrusions, wherein: each protrusion of the first set of protrusions extends to a first length;
and each protrusion of the second set of protrusions extends to a second length that is shorter
than the first length.
10 The length of each protrusion of the second set of protrusions may be between 45 to 50% of
the length of each protrusion of the first set of protrusion.
The protrusions of the support structure may be uniformly positioned around the opening.
15 The first set of protrusions may comprise two diametrically opposing protrusions.
The second set of protrusions may comprise two diametrically opposing protrusions.
The housing may be formed of a first portion and a second portion, the first portion and the
20 second portion being pivotally coupled.
The internal mechanisms of the first portion and the second portion may be identical.
The device may further comprise a hinge coupled to both the first portion and the second
25 portion, the hinge enabling pivotal rotation of the first portion and the second portion of the
housing relative to each other.
The device may further comprise a removeable applicator, and the housing may be further
configured to receive the applicator.
30
4
The applicator may comprise: a first end that can be coupled to the second end of the device;
a second end that can be positioned at the first end of the device and configured to receive
an end effector; and a shaft extending between the first end and the second end.
5 The first end of the applicator may comprise a laterally extending member for releasably
engaging the first end of the housing.
The end effector may be a pair of forceps and the second end of the applicator may comprise
an aperture for housing the tips of the forceps when they are closed.
10
The diameter of the shaft of the applicator may be smaller than the diameter of the shaft of
the electrosurgical instrument.
The shaft of the applicator may comprise a limiting ring, and the diameter of the limiting ring
15 may be larger than the inner diameter of the insulating sleeve.
The protrusions may be angled such that the distance between two diametrically opposing
protrusions is smaller than the shaft of the electrosurgical instrument.
20 According to a second aspect, there is provided a method for applying an insulating sleeve to
an electrosurgical instrument, the electrosurgical instrument comprising an end effector
connected to a shaft by a distal articulation at a distal end of the instrument, the method
comprising: applying the insulating sleeve to a support structure of a device, the device
comprising a housing with a first end, a second end, and a hollow channel extending from the
25 first end to the second end, the support structure being internal to the housing and
configured to interface with the insulating sleeve; progressing the shaft of the electrosurgical
instrument through the hollow channel of the device; and engaging the shaft of the
electrosurgical instrument with the support structure, which pushes the insulating sleeve off
of the support structure and onto the electrosurgical instrument.
30
5
According to a third aspect, there is provided a method for removing an insulating sleeve from
an electrosurgical instrument, the electrosurgical instrument comprising an end effector
connected to a shaft by a distal articulation at the distal end of the instrument, the insulating
sleeve being applied to the distal end of the electrosurgical instrument, the method
5 comprising: positioning the electrosurgical instrument within a device, the device comprising
a housing with a first end, a second end, a hollow channel extending from the first end to the
second end, the channel being configured to receive the electrosurgical instrument, and a
support structure internal to the housing, the support structure being further configured to
interface with an insulating sleeve; progressing the first end of the housing of the device
10 towards the distal end of the surgical instrument, such that the insulating sleeve is brought
into contact with the support structure; and applying force to the housing such that, when
the insulating sleeve is brought into contact with the support structure, the housing
progresses with the support structure of the housing towards the distal end of the surgical
instrument, until the insulating sleeve is removed from the distal end of the electrosurgical
15 instrument.
Brief description of the drawings
The present invention will now be described by way of example with reference to the
20 accompanying drawings. In the drawings:
figure 1 illustrates an electrosurgical instrument to which electrical insulation is to be applied;
figure 2 illustrates an insulating sleeve for electrically insulating an electrosurgical instrument;
figure 3 illustrates an arrangement of the insulating sleeve of figure 2 when it is applied to the
electrosurgical instrument of figure 1;
25 figure 4 illustrates a first view of a device for applying an insulating sleeve to an electrosurgical
instrument;
figure 5 illustrates a view of the housing of the device illustrated in figure 4;
figure 6 illustrates a removeable applicator of the device of figure 4;
6
figure 7 illustrates the arrangement of the device housing of figure 4, the applicator of figure
6 and the insulating sleeve prior of figure 2 to assembly of the insulating sleeve onto the
electrosurgical instrument;
figure 8 illustrates the process of applying an insulating sleeve to the electrosurgical
5 instrument using the device of figures 4-7;
figure 9 illustrates the process of removing an insulating sleeve from the electrosurgical
instrument using the device of figure 4.
Detailed description of the invention
10
An example of the arrangement of a new electrosurgical instrument 100 is illustrated in figure
1. The instrument comprises a shaft 102 and an end effector 104. The shaft 102 is coupled at
its distal end to the end effector 104, and at its proximal end to a surgical robot, which
provides power to and controls the movement of the electrosurgical instrument 100. The
15 surgical robot may comprise a console allowing the electrosurgical instrument 100 to be
electrically manipulated by an operator. The surgical robot may further comprise a number
of different electrosurgical instruments, both electrosurgical and non-electrosurgical.
The end effector 104 is configured for insertion into the body of the patient, and to perform
20 a method of surgery. In the example illustrated in figure 1, the end effector 104 comprises a
pair of curved blades 104a, 104b that form a pair of forceps. The forceps can be used to cut
the organic tissues of a patient during a surgical procedure. It will be appreciated that, whilst
the end effector in figure 1 is illustrated as a pair of forceps, an alternative end effector could
be used in its place. The end effector 104 is coupled to the shaft 102 by an articulation 106.
25 The articulation 106 allows the forceps to rotate about the shaft 102 in at least one degree of
freedom.
During an electrosurgical procedure, power is supplied to the electrosurgical instrument 100
by the surgical robot. This power is supplied in the form of a high frequency, alternating
30 electrical current. Current that is provided to the end effector 104 is passed through the shaft
7
102 of the electrosurgical instrument and the articulation 106. In known electrosurgical
instruments, one or more drive cables located within the shaft are used to power the end
effector. In contrast, for the arrangement illustrated in figure 1, the whole of the
electrosurgical instrument 100, including the shaft 102, becomes live when current is
5 provided to the end effector 104. The current heats the end effector 104 so that, when the
end effector 104 is applied to organic tissue, the heated end effector 104 can coagulate and
desiccate the tissue, which results in the occlusion of blood vessels and halting of bleeding.
The end effector 104 may also be used to penetrate and dissect the tissue.
10 As, for the transfer of current through the electrosurgical instrument 100, the whole of the
instrument 100 becomes live, it is necessary for the shaft 102 and the articulation 106 to be
electrically insulated so as not to cause burns to the patient, either via direct contact or
capacitively. To provide initial protection, the shaft 102 comprises two layers of insulation
along its length. The first layer of insulation is a powder coating 108. The powder coating 108
15 may be an Ethylene Tetrafluoroethylene (ETFE) powder coating. The powder coating 108
extends to cover all but the distal end 112 of the shaft. The second layer of insulation
comprises a heat shrink 110. The heat shrink may be a MT-1000 heat-shrink. The heat shrink
110 ends at the distal end of the shaft, but proximally to the end of the powder coating 108.
The powder coating and heat shrink insulation cannot be applied to the articulation 106 of
20 the electrosurgical instrument 100, as this would limit the range of motion of the articulation.
Furthermore, the distal end of the shaft 112 and the articulation 106 must be capable of being
effectively cleaned and sterilised between surgical procedures. At the same time, it is
important that the distal end of the end effector 104 remains exposed. Where the end
effector is a pair of forceps, it is important that the blades 104a, 104b of the forceps are
25 exposed and are able to perform their full range of motion.
To provide electrical insulation to the distal end of the shaft 112 and the articulation 106 of
the electrosurgical instrument 100, an insulating sleeve is provided. An example of the
insulating sleeve 200 is illustrated in figure 2. The insulating sleeve comprises a first end 202,
30 a second end 204, a plurality of portions 206, 208, 210, and a distal fillet 212. The first end
8
202 and the second end 204 each comprise an opening, and a hollow shaft extends through
the insulating sleeve 200 between these two openings. Each portion of the insulating sleeve
is for interfacing with a different part of the electrosurgical instrument 100 and may comprise
a different internal and external diameter. Alternatively, each portion of the sleeve may have
5 the same internal and external diameters and may be configured to stretch around the
respective parts of the electrosurgical instrument that it is configured to cover. In the example
illustrated in figure 2, the insulating sleeve comprises three portions. The insulating sleeve is
also illustrated as being cylindrical in shape. It will be appreciated that alternative shapes of
insulating sleeve may alternatively be provided.
10
The insulating sleeve 200 is formed of a material such as silicon, which is capable of resisting
high temperatures that arise during electrosurgery. In addition to this, the material of the
insulating sleeve is resistive to fatigue for the range of strains expected during end effector
movement. The material of the insulating sleeve 200 is also elastic, so that it is able to expand
15 to surround the electrosurgical instrument 100. The inner surface of the insulating sleeve 200
is coated to ensure a smooth finish. The coating of the inner surface is glutinous. This enables
the surface of the electrosurgical instrument 100, which is polished, to stick to the inner
surface of the insulating sleeve 200. Thus, high friction between the surface of the
electrosurgical instrument 100 and the insulating sleeve 200 is ensured.
20
The first portion 206 of the insulating sleeve 200 is located at a proximal end of the sleeve.
The first portion 206 is configured to interface with the powder coating 108 located on the
outer surface of the shaft 102. The inner diameter of the first portion 206 of the insulating
sleeve 200 is structured so that, when it is not expanded, it is smaller than the outer diameter
25 of the portion of the shaft comprising the powder coating 108. For example, if the outer
diameter of the instrument shaft comprising the powder coating is 6.8mm, the inner diameter
of the first portion 206 of the insulating sleeve may be 4.2mm. As the insulating sleeve is
made of an elastic material, the inner diameter of the first portion 206 of the sleeve can be
stretched to expand its inner diameter such that it can be applied to the electrosurgical
30 instrument.
9
The smaller inner diameter of the first portion 206 relative to the portion of the shaft
comprising the powder coating 108 ensures a compression fit between the sleeve 200 and
the instrument shaft 102. Thus, the insulating sleeve 200 can be well positioned on the
5 instrument shaft 102 during assembly, such that displacement of the sleeve 200 relative to
the shaft 102 during surgical use is prevented. This is advantageous as it minimises the risk of
the sleeve 200 falling onto the surgical site during use. The inner diameter of the first portion
of the sleeve 206 may be between 60% and 63% of the diameter of the instrument shaft 102.
The inner diameter of the first portion of the sleeve 206 may be between 80 and 88% of its
10 outer diameter. In the example where the inner diameter of the first portion 206 is 4.2mm,
the outer diameter of the first portion may be 5mm. In this example, the inner diameter of
the second portion 206 will be 84% of the diameter of the outer diameter of the second
portion. The inner and outer diameters of the first portion 206 are selected such that the
thickness of its walls allows for the first portion 206 to stretch and cover the shaft 102 without
15 tearing.
The second portion 208 of the insulating sleeve 200 is connected to and located distally of the
first portion 206 of the sleeve. The second portion 208 is configured to interface with the
outer surface of the distal end of the shaft 112 that does not comprise any alternative form
20 of insulation. The inner diameter of the second portion 208 is larger than the inner diameter
of the first portion 206. The inner diameter of the second portion 208 may also be larger than
the outer diameter of the shaft 102. For example, if the outer diameter of the shaft is 6.8mm,
the inner diameter of the second portion may be 4.5mm. As it is wider in diameter than the
first portion 206, the second portion 208 (together with the third portion 210) is easier to
25 position over the shaft after the first portion 206 has been positioned. The inner diameter of
the second portion of the sleeve 208 may be between 65% and a 68% of the diameter of the
instrument shaft 102. The inner diameter of the second portion of the sleeve 208 may be
between 78 and 84% of the outer diameter of the second portion 208 of the sleeve. In the
example where the inner diameter of the second portion 206 is 4.5mm, the outer diameter
10
of the first portion may be 5.56mm. In this example, the inner diameter of the second portion
206 will be 81% of the diameter of the outer diameter of the second portion.
The third portion 210 of the insulating sleeve 200 is connected to and located distally of the
5 second portion 208 of the sleeve. The third portion 210 is configured to interface with the
articulation 106 of the electrosurgical instrument 100. The third portion 210 therefore has a
larger inner diameter than both the first portion 206 and the second portion 208, so that it is
able to encapsulate the articulation 106. For example, where the inner diameters of the first
and second portions are 4.2mm and 4.5mm respectively, the inner diameter of the third
10 portion may be 5.9mm. The inner diameter of the third portion of the sleeve 210 may be
between 85% and 88% of the diameter of the instrument shaft 102. The inner diameter of the
third portion of the sleeve 210 may be between 84 and 89% of the outer diameter of the third
portion 210 of the sleeve. Where the inner diameter of the third portion is 5.9mm, its outer
diameter may be 6.8mm. In this example, the inner diameter of the second portion 206 will
15 be 87% of the diameter of the outer diameter of the second portion.
The distal end of the third portion 210 is further connected to a fillet 212. The fillet 212 is
located distally of the third portion 210, where the second portion 208 is located proximally
of the third portion 210. The fillet decreases in radius as it extends away from the third portion
20 210 such that the inner diameter the distal end of the sleeve, which opposes the proximal
end, is narrower than the inner diameter of the third portion 210. In contrast, the thickness
of the fillet 212 increases as it extends distally. The fillet 212 is configured to interface with
the end effector 104 of the electrosurgical instrument. Where the electrosurgical instrument
is a pair of forceps, the fillet 212 is configured to couple, at its distal end, to the blades 104a,
25 104b, of the forceps. The increased thickness of the fillet 212 at its distal end results in a
thicker ring that surrounds the electrosurgical instrument 100, which enables attachment of
the insulating sleeve 200 to the instrument.
Figure 3 illustrates an exemplary arrangement of the insulating sleeve 200 placed over the
30 electrosurgical instrument 100. In this arrangement the first end 202 of the sleeve interfaces
11
with the distal end of the heat shrink 110 that insulates the shaft 102. The first portion 206 of
the sleeve is positioned over and interfaces with the powder coating 108. The second portion
208 of the sleeve overlies the distal part 112 of the shaft. The third portion 210 of the sleeve
overlies the articulation 106 and the fillet 212 overlies a portion of the end effector 104.
5 Where the end effector is a pair of forceps, the fillet 212 overlies a portion of the blades of
the end effector 104.
The first portion 206 of the sleeve does not necessarily have to directly abut the distal end of
the heat shrink 110. However, to ensure that an operator of the electrosurgical instrument is
10 protected from electrical shocks induced by the live system, it is important that the creepage
and clearance distances between the proximal end of the insulating sleeve 200 and the live
portions of the shaft 102 are maintained. The creepage distance is the shortest distance along
the surface of a solid insulating material between two conductive parts. Clearance distance is
the shortest distance in air between two conductive parts.
15
To ensure that both the creepage and clearance distances are maintained, an appropriate
positioning of the insulating sleeve 200 over the electrosurgical instrument 100 is essential.
This is because it may be difficult to reposition the insulating sleeve 200 once it has been
placed on the instrument 100. The insulating sleeve 200 can be positioned on the shaft 102
20 of the instrument manually. However, this process incurs considerable time and effort.
Manual positioning of the sleeve 200 may also result in perforation of the sleeve with the tip
of the end effector 104 or harm caused by the tip of the end effector if the sleeve is displaced.
A device has been provided to ensure the correct application of an insulating sleeve onto the
25 shaft. An example of this device 400 is illustrated in figure 4. The device 400 comprises a
housing 402 that is configured to house an internal mechanism. The housing 402 is small and
ergonomically arranged so that it can fit within the hand of a user. In the example illustrated
in figure 4, the housing has a generally ovular shape. The housing 402 of the device 400 may
be formed of a thermoelastic polymer, such as polypropylene.
30
12
The housing comprises a first end 404, a second end 406, and a hollow channel 408 that
extends between the first end 404 and the second end 406. The dimensions of the channel
408 are such that it is configured to receive an electrosurgical instrument as illustrated in
figure 1, for example. As illustrated in figure 1, the electrosurgical instrument 100 comprises
5 a shaft 102, a distal articulation 106 and an end effector 104 that is located distally of the
distal articulation. The smallest diameter of the channel 408 must therefore be larger than
the largest diameter of the electrosurgical instrument 100.
The housing 402 further comprises a support structure 410 located internally of the housing.
10 The support structure is configured to support an insulating sleeve as illustrated in figure 2,
for example. The support structure 410 is configured to mount the insulating sleeve 200 such
that the sleeve surrounds the electrosurgical instrument 100 when the instrument is
positioned within the channel 408. The arrangement of the housing 402 is such that, when an
electrosurgical instrument 100 is advanced through the channel from the first end 404 to the
15 second end 406, the insulating sleeve is released onto the instrument by the support structure
410. In figure 4, the insulating sleeve 200 is illustrated as mounted on the support structure
410.
Figure 5 illustrates an alternative view of the housing 402 of the device 400. The housing 402
20 comprises a first part 502 and a second part 504. Preferably, the internal mechanisms of the
two parts 502, 504 are identical. The two parts 502, 504 are pivotally coupled together. In
figure 5, the two parts 502, 504 are coupled together by a hinge 506. The hinge 506 has a first
axis 508 about which the first part 502 and the second part 504 are able to rotate. By forming
the housing 402 from two parts 502, 504, the housing 402 can be opened to enable the
25 electrosurgical instrument 100 to be removed from the housing once the insulating sleeve
200 has been applied to the instrument.
The first and second parts 502, 504 can be connected together using a latching mechanism.
A first portion 510 of the latching mechanism may be located on the first part 502 of the
30 housing 402, and a second portion 512 of the latching mechanism may be located on the
13
second part 504 of the housing 402. The latching mechanism may be secured when the two
parts 502, 504 of the housing are rotated about the first axis 508 of the hinge 506 so that they
interconnect. The latching mechanism may be released to separate the first part 502 and the
second part 504 by applying force to either the first or second portion of the latching
5 mechanism. This application of force may comprise sliding, pushing or pulling either the first
portion 510 or the second portion 512 of the latching mechanism to separate these
components from each other.
In one example, the first portion 510 of the latching mechanism comprises a plurality of pins
10 located in a first position within one of the portions the housing 402 of the device. In the same
example, the second portion 512 of the latching mechanism comprises a plurality of holes
located in a corresponding position to the first position of the pins located in the first portion
402. Latching of the first part 502 of the housing to the second part 504 of the housing is
therefore achieved by insertion of the pins into their corresponding holes. In another
15 example, as illustrated in figure 5, both the first part 502 and the second part 504 of the
housing comprise a plurality of pins and a plurality of holes corresponding to those pins.
The channel 408 of the housing 402 is formed from recesses located in both the first and
second parts 502, 504 of the housing 402. When these parts of the housing are
20 interconnected, the channel 408 forms a closed passage located within the housing 402. The
channel 408 further comprises a first portion 514 and a second portion 516. The first portion
514 of the channel extends along the length of the housing 402 from its first end 404 along a
central axis 518. In figure 5, the axis 518 is illustrated as intersecting the channel 408 in the
first part 502 of the housing. However, it will be appreciated that, when the housing 402 is
25 closed, the axis 518 is located in the middle of the first part 502 and the second part 504 of
the housing. The second portion 516 of the channel extends in a direction opposing the
direction of extension of the first portion 514 of the channel along the length of the housing
402 from its second end 406. The first portion 514 and the second portion 516 of the channel
intersect at a ledge 520. A first part of the ledge 520 is located in the first part 502 of the
30 housing, and a second part of the ledge 520 is located in the second part 504 of the housing.
14
The ledge 520 comprises an opening 522 interconnecting the first portion 514 and the second
portion 516 of the channel 408. The channel 408 may be circular in cross section, such that
both the first portion 514 and the second portion 516 of the channel form a cylinder. The first
5 and second portions 514, 516 may alternatively have a cross section formed from any other
geometric shape. The first and second portions 514, 516 of the channel 408 may have the
same diameter. Alternatively, the second portion 516 of the channel 408 may have a diameter
that is larger than the diameter of the first portion 514 of the channel.
10 The support structure 410 of the housing 402 is located on the ledge 520 that connects the
first portion 514 and the second portion 516 of the channel. More precisely, the proximal end
of the support structure 410 is located on and connected to the ledge 520. The support
structure 410 may be formed of a plurality of protrusions 524. The plurality of protrusions
524 may surround the opening 522 located on the ledge 520. The proximal ends of the
15 plurality of protrusions 524 may thus surround the first portion 514 of the channel.
In the example illustrated in figure 5, each protrusion in the plurality of protrusions 524
extends along an axis that is parallel to the axis 518 of the channel. The plurality of protrusions
524 extends towards the second end 406 of the housing 402. The plurality of protrusions 524
20 further comprises a first set of protrusions 526 and a second set of protrusions 528. Each
protrusion of the first set of protrusions extends to a first length from the ledge 520 towards
the second end 406 of the housing 402. Each protrusion of the second set of protrusions 528
extends to a second length that is shorter than the first length.
25 The length of each protrusion of the second set of protrusions 528 may be between 45 and
50% of the length of each protrusion of the first set of protrusions 526. In one example, the
length of each protrusion of the second set of protrusions 528 is 47% of the length of each
protrusion of the first set of protrusions 526. The length of each protrusion of the first set of
protrusions 526 may be between 20 and 25% of the length of the housing 402 of the device.
30 In one example, the length of each protrusion of the first set of protrusions 526 is 21% of the
15
length of the housing 402 of the device. The length of each protrusion of the second set of
protrusions 528 may be between 8 and 13% of the length of the housing 402 of the device. In
one example, the length of each protrusion of the second set of protrusions 528 is 10% of the
length of the housing 402 of the device. The lengths of the protrusions of the first and second
5 sets of protrusions relative to each other, and to the overall length of the housing, are
selected to optimise the process of applying the sleeve 200 to the surgical instrument 100.
Each protrusion of the plurality protrusions 524 of the support structure 410 may be
uniformly positioned around the opening 522. That is, each protrusion of the first set of
10 protrusions 526 may be uniformly spaced around the opening 522 in the ledge 520 relative
to the other protrusions of that set of protrusions. Correspondingly, each protrusion of the
second set of protrusions 528 may be uniformly spaced around the opening 522 in the ledge
520 relative to the other protrusions of that set of protrusions. As mentioned above, the
housing 402 of the housing 402 is formed from a first part 502 and a second part 504.
15 Preferably, the internal mechanisms of the first part 502 and the second part 504 are
identical. Thus, the first and second parts 502, 504, may comprise an equal number of
protrusions. The protrusions may therefore be equally spaced on the parts of the ledge 520
that are formed by both the first 502 and the second 504 part.
20 In the example illustrated in figure 5, both the first set 526 and the second set 528 of
protrusions comprise two protrusions. A first protrusion of the first set of protrusions 526 is
located on the part of the ledge 520 formed by the first part 502 of the housing, A second
protrusion of the first set of protrusions 526 is located on the part of the ledge 520 formed
by the second part 504 of the housing. Correspondingly, a first protrusion of the second set
25 of protrusions 528 is located on the part of the ledge 520 formed by the first part 502 of the
housing, and a second protrusion of the second set of protrusions 528 is located on the part
of the ledge 520 formed by the second part 504 of the housing. In this example, the first and
second protrusions of the first set of protrusions 526 are diametrically opposing protrusions.
The first and second protrusions of the second set of protrusions 528 are diametrically
30 opposing protrusions.
16
The protrusions of the plurality of protrusions 524 are structured so that, as they extend in a
longitudinal direction away from the ledge 520, they are angled inwards. Hence, the diameter
that is formed by the distance between the tips of each protrusion of the first set of
5 protrusions 524 is smaller than the diameter of the opening 522. Likewise, the diameter that
is formed by the distance between the tips of each protrusion of the second set of protrusions
528 is smaller than the diameter of the opening 522. The diameter that is formed by the tips
of each protrusion of the first set of protrusions 526 may be different to (i.e. either smaller
than or larger than) the diameter that is formed by the tips of each protrusion of the second
10 set of protrusions 528. Alternatively, the diameters of the protrusions of the first set of
protrusions 526 and the second set of protrusions 528 may be the same.
The protrusions of the plurality of protrusions 524 are constructed from a flexible plastic
material. Each protrusion of the plurality of protrusions may further comprise a step 530. The
15 step may be located at the proximal end of each protrusion. The proximal end of each
protrusion is the end that is closest to the ledge 520. The step 530 of each protrusion provides
an increase in diameter of the protrusion at the location of the step over the diameter of the
remaining proximal end of the protrusion.
20 The function of the plurality of protrusions 526 is to locate an insulating sleeve 200 on the
housing 402 so that is arranged to be placed over the electrosurgical instrument 100. When
the first part 502 and the second part 504 of the housing 402 are arranged so that they
intersect, and the housing 402 is closed, the protrusions are disposed in a circular
arrangement around the opening 522 on the ledge 520 of the housing 402. Thus, each step
25 530 of a protrusion in the plurality of protrusions 524 provides a mounting surface on which
the insulating sleeve 200 can be located. More specifically, the first portion 206 of the
insulating sleeve is positioned on the steps of the plurality of protrusions. The position of the
first portion 206 of the insulating sleeve 200 is therefore maintained by the plurality of
protrusions 524.
30
17
The diameter of the circle formed by the distance between the steps 530 of the plurality of
protrusions is larger than the inner diameter of the first portion 206 of the insulating sleeve
200. Thus, the plurality of protrusions 524 is able to stretch the first portion of the sleeve so
that this inner diameter is increased. The inner diameter of the first portion 206 is stretched
5 such that it is larger than the diameter of the shaft 102 of an electrosurgical instrument onto
which the insulating sleeve 200 is to be applied.
The housing 402 may be arranged so that it is ergonomically suited for use by an operator.
The housing 402 may comprise one or more extruded portions 412 that are suited to be held
10 by the hand of a user. As mentioned above, the overall size of the housing 402 is such that it
fits within the hand of a user. The housing 402 may further comprise a honeycomb structure
414 on its exterior. The honeycomb structure 414 provides enhanced gripping during use of
the device 400. The housing 502 may further comprise one or more auxiliary elements 532 to
facilitate the opening of the housing 402. In the exemplary arrangement illustrated in figure
15 5, these auxiliary elements are located close to the second end 406 of the housing 402.
However, it may be appreciated that these elements could be located in any alternative
location along the edge of the first and second parts 502, 504 of the housing 402.
The device 400 further comprises a removeable applicator which is used to guide the
20 electrosurgical instrument 100 through the housing 402 so that the sleeve can be provided to
the instrument. The removeable applicator is illustrated in figure 6.
The applicator 600 illustrated in figure 6 comprises a first end 602, a second end 604 and a
shaft 606 extending between the first end and the second end. The first end 602 is configured
25 such that it can be coupled to the second end 406 of the housing 402. The second end 604 is
configured to be positioned at the first end 404 of the housing 402 and to receive the distal
end of the end effector 104 during its use.
The first end 602 of the applicator 600 comprises a laterally extending member 608. That is,
30 the laterally extending member 608 extends in a direction that is substantially perpendicular
18
to the longitudinal axis of the shaft 606 of the applicator. The laterally extending member
may be symmetrical on either side of a line that is formed by the longitudinal axis of the shaft
606. The laterally extending member 608 is configured to releasably engage the second end
406 of the housing 402. The engagement between the second end of the housing 406 and the
5 laterally extending member 608 is ensured when the first part 502 and the second part 504
of the housing 402 have intersected to close the channel 408 of the housing 402.
The applicator 600 further comprises two latching components 610, 612. The latching
components 610, 612 are located at either end of the laterally extending member 608 and
10 extend towards the second end 604 of the applicator. The latching components 610, 612 are
configured to engage with an opening located at the second end 406 of the housing 402. The
housing 402 may therefore comprise a recess that is complementary to the shape of the
laterally extending member 608.
15 The second end 604 of the applicator 600 may further comprise two portions 614, 616. Each
of the two portions 614, 616 is preferably formed from a rigid plastic, and comprises a
proximal end that is connected to the shaft 606 and a distal end located that opposes the
proximal end. The two portions 614, 616 may configured to separate from each other at their
distal ends. The separation of these portions provides an aperture 618 at the distal part of the
20 second end 604 of the applicator. The aperture 618 is configured to interface with the end
effector 104 of an electrosurgical instrument 100. For example, where the end effector 104
is a pair of forceps, the aperture 618 is configured to interface with and house the distal ends
of the blades 104a, 104b of the forceps when they are closed. When the end effector 104
interfaces with the aperture 618, the longitudinal axis of the shaft 102 of the electrosurgical
25 instrument 100 is aligned with the longitudinal axis of the shaft 606 of the applicator 600.
Thus, when the applicator 600 is placed within the housing 402 of the device and the end
effector 104 is engaged with the aperture 618, the applicator 600 enables the electrosurgical
instrument 100 to be guided though the housing 402 in alignment with the applicator. The
electrosurgical instrument 100 can therefore be guided accurately through the housing 402.
30
19
The diameter of the shaft 606 of the applicator 600 is smaller than the diameter of the shaft
102 of the electrosurgical instrument 100 to be used in combination with that applicator. The
diameter of the shaft 606 of the applicator is similar to the diameter that is formed by the
distance between the tips of each protrusion of both the first set of protrusions 526 and the
5 second set of protrusions 528. The shaft 606 is configured to pass through both the first
portion 514 and the second portion 516 of the channel 408 of housing 402 without interfering
with the opening 522 or the support structure 410 of housing 402. The diameter of the shaft
606 of the applicator is also smaller than the diameter that is formed by the distance between
the tips of each protrusion of both the first set of protrusions 526 and the second set of
10 protrusions 528. Thus, the shaft 606 of the applicator can be progressed through the housing
402 without altering the positioning of the protrusions.
The applicator 600 further comprises a limiting ring 620 located on its shaft 606. The diameter
of the limiting ring 620 is larger than the diameter of the shaft 606. The diameter of the
15 limiting ring 620 is also larger than the inner diameter of the fillet 212 of the insulating sleeve
200. To position the insulating sleeve 200 on the applicator 600, the first end 204 of the sleeve
is slid onto the second end 604 of the applicator and is pushed up the shaft 606 until the filet
212 abuts the limiting ring 620. When the fillet 212 abuts the limiting ring 620, it cannot be
slid any further up the applicator 600. Thus, the limiting ring 620 maintains the position of the
20 insulating sleeve 200 on the shaft 606 before it is placed within the housing 402. That is, the
limiting ring 620 prevents the sleeve from being displaced further towards the first end 602
of the applicator on the shaft 606 during storage due to temperature or time dependent
deformations in the sleeve. This is important as it ultimately ensures that the insulating sleeve
200 is placed in the desired position on the electrosurgical instrument 100.
25
Figure 7 illustrates the arrangement of the housing 402, the removeable applicator 600 and
the insulating sleeve 200 prior to application of the insulting sleeve 200 onto an
electrosurgical instrument 100. To form this arrangement, the insulating sleeve 200 is first
placed on the applicator 600 such that its fillet 212 abuts the limiting ring 620. The applicator
30 600 is then inserted into the housing 402. As the insulating sleeve 200 is arranged around the
20
circumference of the shaft 606 of the applicator 600, the applicator can be used to align the
insulating sleeve to the housing 402.
In the arrangement illustrated in figure 7, the first end 602 of the applicator is coupled to the
5 second end 406 of housing 402. That is, the latching components 610, 612 are engaging with
a corresponding opening in the housing 402. The second end 204 of the insulating sleeve 200
is engaged with the limiting ring 620 of the applicator 600. The first end 202 of the insulating
sleeve 200 is abutting the steps 530 located on the first 526 and second 528 sets of the
plurality of protrusions 524. The insulating sleeve 200 is therefore mounted on the housing
10 402. The aperture 618 located at the second end 604 of the applicator 600 is visible. The
second end of the aperture 604 is located at the first end 404 of housing 402. The aperture
618 is configured to receive the distal end of the end effector 104.
Figure 8 illustrates the method of applying an insulating sleeve 200 to an electrosurgical
15 instrument 100 using the device illustrated in figures 4-7. In order to commence this method,
the insulating sleeve 200 is first arranged so that it is mounted on the support structure 410
of the housing 402. More specifically, the insulating sleeve 200 is mounted on the steps 530
of the plurality of protrusions 524 of the support structure 410, such that the first end 202 of
the insulating sleeve 200 interfaces with these steps. This arrangement is illustrated in the
20 overview of the device that is provided in figure 4.
The insulating sleeve 200 may be mounted to the support structure 410 using the applicator
600. The insulating sleeve 200 may initially be mounted to the applicator 600 so that its
second end 204 (i.e. the distal end of the fillet 212) interfaces with the surface of the limiting
25 ring 620. The applicator 600 may then be placed within the channel 408 of the housing 402
by pivoting the first part 502 and the second part 504 of the housing about axis 508 of its
hinge 506 so that they are separated. The applicator 600 can be placed into the recess that
forms the channel 408 on either the first 502 or second 504 part of the housing, and the first
and second parts can then be closed together. The first portion 206 of the insulating sleeve
30 200 is thus positioned on the support structure 410. The second portion 208 or any further
21
portion of the insulating sleeve 200 may also be placed over the support structure 410. As
mentioned above, the first end 202 of the insulating sleeve 200 should abut the steps 530 on
the plurality of protrusions 524 of the support structure 410. When the insulating sleeve 200
is positioned in this way, the laterally extending member 608 of the applicator 600 interfaces
5 with the second end 406 of the housing. The latching components 610, 612 are therefore
engaged with the second end 406 of the housing 402.
The method of applying an insulating sleeve 200 to an electrosurgical instrument 100 begins
at step 8A when the distal end of the electrosurgical instrument 100 is introduced into the
10 second end 604 of the applicator 600. More specifically, the end effector 104 of the
electrosurgical instrument 100 may be introduced into the aperture 618 of the applicator 600.
Where the end effector 104 is a pair of forceps, the closed blades 104a, 104b of the forceps
may be inserted into the aperture 618. When the end effector 104 is engaged with the
aperture 618, the longitudinal axis of the shaft 102 of the surgical instrument 100 is aligned
15 with the longitudinal axis of the applicator 600.
As mentioned above, the first and second portions 614, 616 are preferably formed of a rigid
plastic, and the aperture 618 is provided by the separation of these rigid portions at their
distal ends. In an alternative example, the first and section portions 614, 616 may be formed
20 of a flexible plastic. In this example, the distal ends of the first and second portions 614, 616
adjoin each other when no end effector has been applied to the applicator. The insertion of
an end effector pushes the distal ends of these portions 614, 616 apart to reveal the aperture
618.
25 At step 8B, the applicator 600 is continuously progressed through the housing 402 by pushing
the shaft 102 of the electrosurgical instrument 100 along the longitudinal axis 518 of the
channel 408. The insulating sleeve 200 and the housing 402 remain stationary. The
progression of the applicator 600 through the housing 402 may be done manually. As the end
effector 104 of the electrosurgical instrument 100 is engaged with the aperture 618 of the
30 applicator 600, pushing the electrosurgical instrument 100 forces the applicator 600 to
22
progress through the housing 402. The diameter of the shaft 606 of the applicator 600 is
configured such that it can pass through the inner diameters of the insulating sleeve 200 when
the insulating sleeve 200 is positioned on the support structure 410 of the housing 402.
5 At step 8C, the second end of the applicator 604 passes through the opening 520 and the
support structure 410. Up until this point, the insulating sleeve 200 is still positioned on the
support structure 410. The shaft 102 of the electrosurgical instrument is significantly wider
than both the applicator 600 and the distance between the protrusions of the support
structure 410 so, as the shaft 102 is progressed through the opening 520, it engages with and
10 pushes the plurality of protrusions outwards. This, in turn, expands the inner diameter of the
first portion 206 of the sleeve that is positioned on the support structure 410. This expansion
in the inner diameter of the first portion results in an increase in friction that pushes the
sleeve upwards towards the second end 406 of the housing 402. As mentioned above, the
diameter that is formed by the distance between the tips of each protrusion of the first and
15 second sets of protrusions is smaller than the diameter of the opening 520. Thus, as the
electrosurgical instrument 100 and the applicator 600 continue to advance through the
housing 402, the insulating sleeve 200 is pushed off of the steps 530 of the plurality of
protrusions 524 of the support structure 410 and onto the shaft of the electrosurgical
instrument 100 through the engagement of the support structure with the shaft 102. When
20 the second end 604 reaches the fillet 212 of the insulating sleeve, the engagement between
the second end and the fillet results in additional friction which assists with completing the
adherence of the sleeve 200 to the instrument 100.
At step 8D, the insulating sleeve 200 has advanced such that its first end has passed the tips
25 of the protrusions of the second set of protrusions 528. At this point, the insulating sleeve
200 is only interfacing with the support structure 410 by means of the protrusions of the first
set of protrusions 526. The protrusions of the first set of protrusions 526 apply less force to
the insulating sleeve than the combination of the first and second sets of protrusions 524. For
this reason, less force is required at this stage to continue to progress the electrosurgical
23
instrument 100 through the housing 402. The inner diameter of the portion of the insulating
sleeve 200 that is still attached to the support structure 410 is also reduced.
At step 8E, the insulating sleeve 200 is further advanced such that it is removed from the tips
5 of the protrusions of the first set of protrusions 526. The sleeve 200 is therefore fully applied
to the electrosurgical instrument 100. The diameter of the sleeve 200 has reduced so that it
adheres to the electrosurgical instrument 100. The applicator 600 can be removed from the
insulating sleeve 200 after assembly by pulling on the first end 602 of the applicator so that
the first and second portions 613, 616 of the applicator are forced out of the inner diameter
10 of the third portion 210 of the sleeve.
Once the insulating sleeve 200 has been applied to the electrosurgical instrument 100, the
housing 402 may then be removed from the instrument. This is done by releasing the latching
mechanism of the housing and rotating the first and second parts 502, 504 of the housing
15 away from each other about the axis 508 of the hinge 506. The electrosurgical instrument 100
may then be manually removed from the housing 402. If necessary, the insulating sleeve 200
can be manually adjusted on electrosurgical instrument 100 after its application, to ensure
that its positioning is correct. The housing 402 may be retained for future use. The housing
402 can be applied to and removed from the electrosurgical instrument 100 whilst the
20 instrument is coupled to a surgical robot.
As previously mentioned, the plurality of protrusions 524 in the support structure 410
comprises a first set of protrusions 526 and a second set of protrusions 528. The protrusions
of the second set of protrusions 528 are shorter than the protrusions of the first set of
25 protrusions 526. This is advantageous as it enables the insulating sleeve 200 to be supported
by all of the protrusions of the support structure 410 before the electrosurgical instrument
100 is passed through the sleeve. This means that a suitable amount of force is applied to the
inner diameter of the first portion 206 of the insulating sleeve, and that it can be held so that
it is wide enough for the shaft 606 of the applicator 600 to pass through. Once the shaft 606
30 has passed through the insulating sleeve 200, it is easier to continue to push the
24
electrosurgical instrument 100 through using a smaller number of protrusions. Thus, when
the insulating sleeve 200 is advanced off of the support structure 410 its first end passes the
tips of the protrusions of the second set of protrusions 528 and is supported only by the ends
of the protrusions of the second set of protrusions 526. In this way, the amount of force that
5 is applied to widen the inner diameter of the first portion 206 of the insulating sleeve 200 is
varied to correspond to the path of the insulating sleeve 200 as it is applied to the
electrosurgical instrument 100.
The housing 402 of the device 400 may also be used to remove an insulating sleeve 200 from
10 the electrosurgical instrument 100. The removal of the insulating sleeve 200 may be
performed without the use of the applicator 600. The steps involved in removing the
insulating sleeve 200 from the electrosurgical instrument 100 are illustrated in figure 9.
The removal process begins at step 9A where the first and second parts 502, 504 of the
15 housing 402 are closed around the shaft 102 of the electrosurgical instrument 100 by a user.
The electrosurgical instrument 100 is therefore positioned within the housing 402. The
insulating sleeve 200 is positioned on the shaft 102 and located distally of the second end of
the housing 402. At step 9B the shaft 102 is held stationary and the housing 402 is progressed
by the user towards the distal end of the electrosurgical instrument 100, i.e. towards the end
20 effector 104.
At step 9C the support structure 410 of the housing 402 interfaces with the first end 202 of
the insulating sleeve 200. Where the support structure 410 comprises a first 526 and second
set 528 of protrusions as described above, a number of portions of the first end 202 of the
25 insulating sleeve 200 interface with the distal ends of the protrusions of the first set of
protrusions 526. Where the first set of protrusions 526 comprises two protrusions, two
portions of the first end 202 of the insulating sleeve 200 interface with the distal ends of these
protrusions. The tips of the protrusions apply a resistive force to the interfacing portions of
the insulating sleeve 200. The portions of the insulating sleeve 200 that interface with the
25
distal end of the protrusions are therefore caught on the distal end of the protrusions and
move with the housing 402 as it is advanced further towards the end effector 104.
At step 9D a force is applied to the housing 402 such that it is advanced further along the
5 electrosurgical instrument 100, and a number of further portions of the first end 202 of the
insulating sleeve 200 interface with the distal ends of the protrusions of the second set of
protrusions. Where the second set of protrusions 528 comprises two protrusions, two
portions of the first end 202 of the insulating sleeve interface 200 with the distal ends of the
protrusions. Thus, there are now twice the number of portions of the first end 202 of the
10 insulating sleeve 200 to which a resistive force is applied. The user therefore requires less
force to continue to progress the housing 402 towards the end effector 104.
At step 9E a force is continually applied until the electrosurgical instrument 100 is moved past
the tips of the protrusions of the support structure 410. The insulating sleeve 200 continues
15 to move with the housing 402, whilst the shaft 102 of the instrument 100 remains stationary.
Thus, the insulating sleeve 200 is separated from the electrosurgical instrument 100 as the
housing 402 reaches the end effector 104. The insulating sleeve 200 can then be discarded.
The applicant hereby discloses in isolation each individual feature described herein and any
20 combination of two or more such features, to the extent that such features or combinations
are capable of being carried out based on the present specification as a whole in the light of
the common general knowledge of a person skilled in the art, irrespective of whether such
features or combinations of features solve any problems disclosed herein, and without
limitation to the scope of the claims. The applicant indicates that aspects of the present
25 invention may consist of any such individual feature or combination of features. In view of
the foregoing description it will be evident to a person skilled in the art that various
modifications may be made within the scope of the invention.
26
27
WE CLAIM:
1. A device for applying an insulating sleeve to an electrosurgical instrument, the device
comprising:
a removable applicator; and
5 a housing configured to receive the removable applicator, the housing comprising:
a first end;
a second end;
a hollow channel extending from the first end to the second end, the channel
being configured to receive an electrosurgical instrument comprising an end effector
10 connected to a shaft by a distal articulation;
a support structure internal to the channel, the support structure being
configured to:
support an insulating sleeve such that the insulating sleeve surrounds
the electrosurgical instrument when the electrosurgical instrument is received
15 by the channel; and
when the electrosurgical instrument is advanced through the channel
from the first end to the second end, release the insulating sleeve onto the
electrosurgical instrument.
20 2. A device as claimed in any claim 1, wherein the applicator comprises:
a first end that can be coupled to the second end of the housing;
a second end that can be positioned at the first end of the housing and configured to
receive an end effector; and
a shaft extending between the first end and the second end.
25
3. A device as claimed in claim 2, wherein the first end of the applicator comprises a laterally
extending member for releasably engaging the first end of the housing.
4. A device as claimed in claim 2 or claim 3, wherein the second end of the applicator
30 comprises a first portion and a second portion, wherein each of the first and second portions
comprises a proximal end that is connected to the shaft of the applicator, and a distal end
28
that opposes the proximal end, wherein the first and second portions are configured to
separate from each other at their distal ends.
5. A device as claimed in claim 4, wherein the separation of the first and second portions at
5 their distal ends provides an aperture at the distal part of the second end of the applicator,
the aperture bring configured to interface with the end effector of the electrosurgical
instrument.
6. A device as claimed in claim 5, wherein the end effector is a pair of forceps and the second
10 end of the applicator comprises an aperture for housing the tips of the forceps when they are
closed.
7. A device as claimed in any of claims 1 to 6, wherein the diameter of the shaft of the
applicator is smaller than the diameter of the shaft of the electrosurgical instrument.
15
8. A device as claimed in any of claims 1 to 7, wherein the shaft of the applicator is configured
to pass through the hollow channel of the housing without interfering with the support
structure of the housing.
20 9. A device as claimed in any of claims 1 to 8, wherein the diameter of the shaft of the
applicator is configured such that it can pass through the inner diameter of the insulating
sleeve when the insulating sleeve is positioned on the support structure of the housing.
10. A device as claimed in any of claims 1 to 9, wherein the shaft of the applicator comprises
25 a limiting ring, and wherein the diameter of the limiting ring is larger than the inner diameter
of the insulating sleeve.
11. A method for applying an insulating sleeve to an electrosurgical instrument, the
electrosurgical instrument comprising an end effector connected to a shaft by a distal
30 articulation at a distal end of the instrument, the method comprising:
29
applying the insulating sleeve to a support structure of a device, the device
comprising:
a removable applicator comprising a first end, a second end, and a shaft
extending between the first end and the second end; and
5 a housing configured to receive the removable applicator, the housing
comprising a first end, a second end, and a hollow channel extending from the first
end to the second end, the support structure being internal to the channel and
configured to interface with the insulating sleeve;
inserting the end effector of the electrosurgical instrument into the second end of the
10 applicator;
progressing the shaft of the electrosurgical instrument and the applicator through the
hollow channel of the device;
progressing the second end of the applicator through the support structure; and
engaging the shaft of the electrosurgical instrument with the support structure, which
15 pushes the insulating sleeve off the support structure and onto the electrosurgical
instrument.
12. A method as claimed in claim 11, wherein progressing the second end of the applicator
through the support structure further comprises engaging the second end of the applicator
20 with a distal end of the insulating sleeve to provide additional friction which assists with
completing the adherence of the insulating sleeve to the electrosurgical instrument.
13. A method as claimed in any of claims 11 to 12, wherein the method further comprises
removing the applicator from the insulating sleeve after assembly by pulling on the first end
25 of the applicator such that the second end of the applicator is forced out of the inner diameter
of the sleeve.