The present invention relates to devices for destroying and removing
unwanted materials such as calculi, deposits and tissues (for example, polyps, tumor
cells) from body lumens, and more particularly to laser lithotripsy treatment of
Open surgical intervention was once the standard treatment for the
removal of calculi or stones, especially when such calculi are deposited in a body
lumen other than the bladder. But other less invasive techniques have emerged as
safe and effective alternatives. Lithotripsy, the crushing of stones that develops
in the body into fragments that are easier to remove, is one such technique. Lithotripsy
devices have been developed which utilize electrohydraulic probes, ultrasonic probes,
electromechanical impactors, or a pin driven by compressed air. These devices typically
use percutaneous endoscopic techniques and are configured to be introduced into
the body through small puncture sites to avoid open surgical intervention. Focused
shock waves can also be delivered from an external source in a non-invasive procedure
known as extracorporeal shock wave lithotripsy (ESWL).
Recently, lasers have been used as an alternative source of energy
in lithotripsy, especially for the destruction of renal and bilary stones. Lasers
are suited for minimally invasive lithotripsy because the diameter of the laser
fiber is small and the aperture of the working channel can be minimized. An extensive
review of the use of lasers for lithotripsy is provided in the book entitled "Laser
Lithotripsy," edited by R. Stein, Springer Verlag, 1988. A fiber optic that travels
along the longitudinal axis of a rigid or flexible endoscope typically transmits
the laser beam. Various types of laser lithotripsy systems with a variety of laser
sources, including pulsed dye laser, alexandrite laser, neodymium laser and holmium
laser, have been developed.
A common problem in intracorporeal lithotripsy treatment is the difficulty
in restricting target movement. For example, when using pulsed lasers such as the
holmium yttrium-aluminum-garnet (Ho:YAG) laser, higher frequency pulsation and higher
energy in each pulse produce quicker fragmentation of the stone, but also produce
significant stone mobility, which decreases treatment efficiency. Lower frequency
of pulsation and lower pulse energy may result in less significant stone mobility,
but the treatment time will be prolonged. Regardless of energy level of each emission,
stones of smaller sizes present an inherent mobility problem. Incomplete lithotripsy
treatment of smaller stones or debris can leave a nidus for future stone growth.
Another problem often encountered by a lithotripsy endoscopist involves
the suction tube that is found in some endoscopes. Such a conduit is generally connected
to a pump that produces a vacuum when in operation and clogging at distal ends by
stones and their fragments has been widely reported. See, e.g. U.S. Patent
No. 4,146,019 to Bass et al. Severe clogging may necessitate repeated removal, cleaning
and reinsertion of the endoscope during an operation.
A laser powered surgical instrument, and more particularly a technique
for generating plasma from input laser pulses wherein the plasma creates shockwaves
that are used to fracture tissue positioned or held at an opening near a distal
end of the surgical instrument, is described in International Patent Application
Publication No. WO 95/24867.
US 5,437,659 discloses a device according to the preamble of claim
Summary of the Invention
An object of the present invention is thus to restrict the movement
of targets of lithotripsy treatment, especially small stones and stone fragments.
Another object of the invention is to remove stone fragments resulting from a lithotripsy
treatment in a more complete and immediate manner. Yet another object of the invention
is to solve the problem of clogging at the distal region of a suction conduit used
The present invention as defined in independent claim 2 provides a
device for the destruction and removal of unwanted materials such as calculi, deposits
and tissues (e.g., polyps and tumor cells) from a patient's body lumen. The invention
achieves these objects by combining a suction conduit with a high-energy delivery
system such that at least some of the high energy transmitted is directed to a region
near the distal end of the suction conduit. For example, some of the energy can
be directed inside, outside, at the face of the tip or a combination thereof. As
a result, the energy destroys materials stuck at the distal end of the suction conduit
and provides the user with a suction device that is equipped with a non-clogging
The devices of the invention comprises a suction conduit connected
to a pump for suction and a second conduit connected to an energy source for transmitting
high energy. Once the suction conduit is in operation, it keeps stones or stone
fragments near its tip, stabilizing the movement of the stone. The second conduit
is designed to direct a portion of the high energy into, across, and/or outside
of the distal end of the suction conduit and thus onto the stones or stone fragments.
The energy fragments, pulverizes or erodes stones, including those caught by the
force of suction onto the tip of the suction conduit, into smaller parts or dusts,
and the suction conduit can instantaneously evacuate the stone debris. For example,
in a preferred embodiment where Ho:YAG laser is used as the energy source, the laser
energy continues to break down fragments that are still too large to enter the suction
conduit while knocking them off the suction tip temporarily thus preventing clogging
of the tip. A portion of the energy may also be directed into a portion of the lumen
of the suction conduit, thereby preventing clogging that would have occurred after
debris entered the conduit.
The device of the invention takes full advantage of the suction force
in removing debris instantaneously from the site of the treatment, allowing a more
complete and speedy treatment. Also, by directing a high energy towards the distal
region of the suction conduit, the devices point the energy into a region where
targets are accumulated and relatively immobilized by the suction. The devices and
methods thus offer enhanced treatment efficiency by permitting a more thorough removal
of debris and by avoiding operational difficulties associated with a clogged suction
In one aspect, the devices of the invention can also be equipped with
structures such as barriers or shields in the distal region of the suction conduit
to help block large particles. In another aspect, the devices of the invention use
multiple energy conduits bundled or dispersed in or around the wall of the suction
conduit. Yet in another aspect, the devices use multiple conduits bearing indicia
or marking that permit their identification during a procedure. In still another
aspect, the devices of the invention direct energy towards the distal region of
the first suction conduit with or without a separate optical apparatus such as mirrors,
lenses, prisms for example.
The device of the invention can be used for the removal of stones
and calcifications throughout the body. First, the device is inserted into the body
lumen of a patient and the distal end of the suction conduit is positioned near
a stone. Then, a high energy is transmitted by the energy conduits and directed
to the distal region of the suction conduit, thereby breaking up stones stuck at
the distal region and removing its fragments through suction.
The devices can also be utilized for the removal of soft tissue such
as polyps or tumor cells. For example, the device is first inserted into the body
lumen of a patient and the distal end of the suction conduit is positioned near
the tissue to be removed. Then, a high energy is transmitted by the energy conduits
and directed to the distal region of the suction conduit and thereby shearing off
the tissue and removing it through suction. Additionally, the devices can be used
for orthopedic applications and endoscopic applications such as arthroscopy and
endoscopic retrograde cholangio-pancreatiography (ERCP).
The foregoing and other objects, aspects, features, and advantages
of the invention will become more apparent from the following description and from
Brief Description of the Drawings
In the drawings, like reference characters generally refer to the
same parts throughout the different views. Also, the drawings are not necessarily
to scale, emphasis instead generally being placed upon illustrating the invention.
Only Fig. 8A and 11 constitute an embodiment according to the invention.
- FIG. 1A is a perspective view of an embodiment of a medical device with two
- FIG. 1B is a perspective view of an embodiment of a medical device with two
conduits and an energy-directing apparatus.
- FIGS. 2A-2D are longitudinal cross-section views of various embodiments of the
distal end of the suction conduit taken along line 6-6 in FIG. 1A.
- FIG. 2E is a perspective view of an embodiment of a suction conduit with a mesh-cap.
- FIG. 2F is a perspective view of an embodiment of a device with a curved barrier
at the distal end of the suction conduit.
- FIG. 3A is a perspective view of an embodiment of a device with an energy-transmitting
conduit that has endoscopically discernable external markings.
- FIG. 3B is a perspective view of an embodiment of an energy-transmitting conduit
with an alternative marking pattern.
- FIG. 3C is an elevated perspective view of an embodiment of a medical device
with a twisted bundle of laser fibers.
- FIG. 4 is a partly cross-sectional view of an embodiment of a laser lithotripsy
device with a housing.
- FIG. 5A is a perspective view of an embodiment of a device with a multi-channel
- FIG. 5B is a longitudinal cross-section view of the device in FIG. 5A taken
along line 6-6 in FIG. 5A.
- FIGS. 6A-6C are schematic views of modified distal ends of laser fibers.
- FIG. 7A is a schematic longitudinal cross-section view of an angled tip of a
laser fiber manufactured by etching.
- FIG. 7B is a side view of laser fiber tip applied with a reflective coating.
- FIGS. 8A-8B are partly cross-sectional views of embodiments of a laser lithotripsy
device with an optical apparatus with that of Fig. 8A being configured in accordance
with the invention.
- FIG. 9 is a schematic longitudinal cross-section view of another embodiment
with an optical apparatus.
- FIG. 10A is a perspective view of an embodiment of a device with multiple channels
for laser fibers surrounding a suction conduit.
- FIG. 10B is a radial cross-section view of the device in FIG. 10A taken along
line 6-6 in FIG. 10A.
- FIG. 11 is a schematic view of a tissue-removing device with an optical apparatus
in accordance with an embodiment of the invention.
Distal region: a region near or around, both inside and outside and
including, an end that is farther away from the origin of attachment.
Conduit: a channel or a tubing for conveying energy or matter.
The device of the present invention combines an energy-transmitting
means with a suction means to enhance the efficiency of material removal from a
body lumen. In doing so, it solves both the problem of calculi mobility and clogging
at the distal region of a suction means used in such medical procedures. The devices
comprise at least a suction conduit and a high-energy conduit, and the energy transmitted
is at least partly directed to the distal region of the suction conduit. Other elements
such as viewing instruments, an illumination means or an irrigation conduit can
be further combined with these elements.
Referring to FIGS. 1A and 1B, a device comprises a suction conduit
1 and an energy-transmitting conduit 2. The suction conduit
1 is connected at its proximal end to a pump 3 that creates a vacuum.
The energy-transmitting conduit 2 is connected at its proximal end to a high-energy
source 4 and transmits and directs the high energy to the distal region
5 of the suction conduit 1. The suction conduit 1 and the energy-transmitting
conduit 2 can be co-extruded, otherwise attached to each other or remain
separate. Further, one can be inside the other. Directing the high energy to the
distal region 5 may be achieved without additional apparatuses, as in FIG.
1A, or may involve at least one additional optical apparatus 30, as illustrated
in FIG. 1B.
The suction conduit can be made of a variety of flexible or rigid
materials or a combination of both, such as stainless steel or plastics. To improve
conduit's resistance against kink-formation or against collapse under vacuum pressure,
and to preserve flexibility in the meantime, either or both of the conduits can
be braided or wound with fibers made of materials such as metals or plastics. The
conduit may have coatings on its inside or outside for various purposes, for example,
for protection against corrosion by body fluids or for insulation against the high
energy emitted towards its distal region. It can be of any dimension convenient
for its intended use. It can be further inside a housing or a sheath. It can house
the energy-transmitting conduit by itself. It can be fixedly integrated into a larger
instrument or slidingly inserted into the instrument such as described in U.S. Patent
No. 4,146,019 to Bass et al.
A stainless steel conduit can be passed through a rigid endoscope.
A suction conduit made of a flexible material (such as plastic or a super elastic
alloy such as Nitinol) can be passed through a flexible endoscope. A preferred embodiment
is an elongated polypropylene tubing of 3.175 mm (1/8 inch) outside diameter that
can be used in an endoscope. The devices of the invention may include multiple suction
The proximal end of the suction conduit is connected to a pump 3,
which provides a vacuum when operated. A control mechanism can be further added
to the system to modulate the intensity of the vacuum.
The distal end 8 of the suction conduit 1 may assume
any shape convenient for its intended use. For example, a suction conduit
1 may have a planar face 7 at its distal end, as depicted in FIGS.
2A and 2B. In FIG. 2B, the face 7 of the distal end is at a beveled angle
to the conduit 1's longitudinal axis. The face 7 may also assume a curved
form, for example, ellipsoidal as shown in FIG. 2C. Alternatively, as shown in FIG.
2D, the suction conduit 1's distal end may contain at least one side aperture
39. Configurations of the distal end such as those in FIGS. 2B-2D will effectively
provide at least one side opening, resulting in direct flow41 from both the
side and the front of the suction conduit 1. Where the devices of the invention
are used to remove materials from the walls of a body lumen, embodiments having
side openings are preferable, because these side openings readily access target
materials, avoiding having to bend the tip. Furthermore, the distal end of the suction
conduit can be made of a material different from the body of the conduit. For example,
one might want to make the distal end with a more heat-resistant material to withstand
high energy directed to it. It may also be desirable to use a more impact-resistant
material to withstand the initial impact from stones drawn by the suction force.
Additional structures at the distal region may help prevent clogging
of the suction conduit. For example, a filter, a screen, a mesh, a shield or other
barriers can be molded onto or otherwise attached to the distal region of the suction
conduit. Referring to FIG. 2E, a mesh 9 is attached onto the distal end
8 of the suction conduit 1. The mesh 9 may be placed further
inside or outside the distal end 8. Alternatively, several such barriers
may be placed along the length of the suction conduit 1.
FIG. 2F shows an example of a barrier positioned outside the distal
end of the suction conduit. A channel 12 enclosing an energy-transmitting
conduit (a laser fiber 22 in this case) is inserted directly in the suction
conduit 1. The distal end of the channel 12 is a curved barrier
25, forming a cap over the distal end 8 of the suction conduit
1, and leaving a gap 33 preferably for about 1-10 mm. The gap
33 is set to admit stone fragments having a size smaller than the suction
conduit 1 or than the space between the suction conduit 1 and the
channel 12. The distal end 28 of the laser fiber 22 is disposed
in the distal region of the channel 12. In the particular embodiment in FIG.
2F, the end 28 is outside the barrier 25, but it can be flush with
or receded closely inside the barrier 25. Also, there may be multiple laser
fibers enclosed in the channel 12. The barrier 25 can be made of any
solid material that can withstand the energy emitted from the distal end
28 and be of sufficient hardness to withstand the impact of stones drawn
by the suction force. The barrier 25 is preferably made of light-transmitting
materials such as glass or quartz so that it acts as a lens for the laser emitted
from the tip 28. The tip 28 can be inside, flush with or outside the
barrier 25 and it may be modified, as detailed in later sections, to diffuse
or deflect light side-wise or backward. Once the pump 3 is in use, fluid
flow will direct mobile particles, such as stone fragments 34a towards the
periphery of the barrier 25 and away from the fiber tip28. As a result,
particles must go through the gap 33 between the barrier 25 and the
distal end 8 to enter the suction conduit 1. The size of barrier
25 can vary as long as the gap 33 is narrow enough to effectively
prevent clogging of the suction conduit. In embodiments where the energy-transmitting
conduit is closely receded inside the barrier 25, the large surface area
of the barrier exposed to the flow of liquid will help cooling the barrier off rapidly.
Other techniques are well known in the art and are described in publications,
such as U.S. Patent Nos. 5,281,231 to Rosen et al. and 5,443,470 to Stem et al.,
and "The Swiss Lithoclast: a New Device for Intracorporeal Lithotripsy" by Denstedt
et al. in September 1992's "The Journal of Urology".
The contemplate energy sources known to one of ordinary skills in
the medical profession for fragmenting, coagulating, or vaporizing various unwanted
materials from a body lumen. Such an energy could be mechanical, electric, chemical
or a combination thereof. The energy may be delivered in the form of heat, electric
current, sparks, laser radiation, radio frequency (RF), ultrasonic wave, mechanical
vibrations, ballistic impact, hydraulic shock or chemical corrosives.
In a preferred embodiment, the energy is laser energy with a wavelength
that is highly absorbable in a liquid medium. Typically such wavelength regions
are the mid-infrared portion of the spectrum from about 1.4 to about 11 micrometers
and in the ultraviolet portion of 190-350 nanometers. Lasers which can be utilized
in the present invention are thulium (Th), holmium (Ho), Erbium:yttrium-aluminum-garnet
(Er:YAG), HF, DF, CO, and CO2 in the mid-infrared region, and excimer
lasers in the ultraviolet region.
In a preferred embodiment, a Ho:YAG laser is utilized. The holmium
laser is useful because it produces fine dust and small debris rather than stone
chunks, and thus facilitates removal of the stone. The Ho:YAG laser can be used
not only for the treatment of calculus, but also for soft tissue. The holmium laser
energy is typically transmitted through a fiber. When a holmium laser, after travelling
the length of the fiber, is fired into a liquid medium the laser energy produces
a vaporization bubble.
The Ho:YAG laser produces light at a wavelength of 2.0 to 2.1 microns,
depending on the precise formulation of the holmium rod, in a pulsed fashion. In
one configuration, the laser produces light at a wavelength of 2.09 microns. These
wavelengths are well absorbed by water and other liquid mediums. All stones in a
body lumen (including cystine calculi) absorb this wavelength well, regardless of
the stone color because of the water in the stone and on the stone surface. This
is a major improvement over previous laser sources such as pulsed dye laser, the
effectiveness of which depends on pigmentation on the target. The pulse duration
of Ho:YAG laser also produces photoacoustic effects that aid stone fragmentation.
In a particular embodiment, the Sharplan 2025 Holmium:YAG Surgical Laser is utilized
as a source of laser energy.
In suitable laser systems, the energy of each pulse and the pulsation
frequency can be varied. Generally, high frequency of pulsation and high energy
produce a quick fragmentation but also produces a significant amount of stone mobility.
Lower frequency of pulsation and lower energy is more precise but the overall treatment
time is prolonged. High frequency of pulsation and high energy can be used by the
devices of the present invention because the suction force limits stone movement.
By combining suction with a laser delivery system in accordance with the invention,
the overall efficiency of treatment is improved. In particular, higher powers, more
efficient lasers, such as holmium lasers, can be used even when small stones are
present because the suction helps keep the small stones in the path of the laser.
Preferably, the energy levels used are between about 0.2 and 2.8 Joules per pulse
and the frequency is between about 5 and 20 Hertz. Typical pulse durations are about
200-400 microseconds. Preferably, the pulse duration is 250 microseconds.
Referring again to FIGS. 1A and 1B, a high-energy source
4 is connected to the proximal end of the energy-transmitting conduit
2. This conduit 2 should be made of a material that is suitable for
the transmission of the energy used in the device and variables of its dimension
(such as length, diameter and shape) should be suitable for the intended use of
the device. It can be further inside a housing or a sheath, such as the suction
conduit itself. The invention can have more than one conduit transmitting the high
energy. Some or all of them can be fixedly integrated into a larger instrument or
slidingly inserted into an instrument.
In a preferred embodiment, this energy-transmitting conduit is a low
density, optical quartz fiber that can be used to transmit laser energy. Generally,
the laser fiber extends from about 50 to 500 cm. Preferably, the laser fiber extends
from about 80 to 100 cm. These fibers range in their core size from about 200 to
1000 microns. Preferably the core size of the laser fiber is between 300 and 550
In another embodiment, the medical device comprises a plurality of
mobile components within a housing, and at least one of the mobile components has
a discernable pattern of indicia disposed on the outer surface of its distal region.
The plurality of mobile components may be at least two of any components of a medical
device used in a body lumen, including but not limited to, laser fibers, fiber optics,
catheters and guidewires.
For example, in FIGS. 3A and 3B, the energy-transmitting conduit
2 is a laser fiber jacketed with a pattern of indicia 23 that aids
detection of its movement inside a body lumen through a viewing instrument. An example
of a viewing instrument is an endoscope that contains a fiber optic illumination
source and a fiber optic lens for viewing. Typically, the scope view 29 shows
a small section of the laser fiber near the fiber's distal end. However, commercially
available laser fibers generally have no distinguishing marking on the outside--they
are generally jacketed in a monochromatic (e.g., black) and glossy plastic wrapping.
One aspect of the invention is to provide discernable markings or indicia
23 for the energy-transmitting conduit and other mobile components in the
device. The markings only needs to appear on the section that is to be seen through
the viewing instrument--in the case of an endoscope, the distal region of the fiber
visible under the scope view 29. The spiral and checkered patterns, as shown
in FIGS. 3A and 3B respectively, are examples of preferred embodiments because these
patterns indicate, in the scope view 29, conduit movements both along and
about the longitudinal axis. Further, the energy-transmitting conduit and any tubular
components (such as a guidewire) viewable through the endoscope should have different
markings for the user to tell them apart. This can be accomplished through different
colors or patterns. This inventive aspect contributes to the overall goal of the
invention when movements of the components are desired for operating the device
or the movements actually take place, and where direct visual monitoring of such
movements will aid the operation of the device.
To make components of the devices further discernable when combined
with a viewing instrument such as an endoscope, a non-reflective or low-reflective
coating as a pattern of indicia can be applied to these conduits to soften light
reflected from them. In an endoscope with a means of illumination, the light is
often so intense that the user finds it difficult to view through the viewing instrument.
A coating that reduces light reflection from the laser fiber jacket, for instance,
will solve that problem.
Referring to FIG. 3C, multiple laser fibers 13-15 are housed
in a channel 12 of a larger instrument, such as an endoscope and the arranged
fibers provide markings, as a whole, that are endoscopically discernable. There
can be a variety of ways of bundling multiple conduits, such as spirally twisting
the bundle (as in FIG. 3C), braiding into a bundle, gluing, tying or fitting tightly
into a channel of a housing. Twisting, braiding or otherwise tightening the association
of multiple fibers retains much of the flexibility of individual fibers. It is easier
to move bundled fibers than unbundled ones inside a housing, whether along or about
the housing's longitudinal axis. In a preferred embodiment, each of the three fibers
is jacketed in a sleeve of a different color, forming an overall spiral pattern
when inserted into an endoscope. The same principle applies to other numbers of
energy-transmitting conduits as long as endoscopically discernable patterns are
provided by the overall bundle.
Directing at least a portion of the energy emitted towards the distal
region of the suction conduit can be accomplished with the laser fiber itself as
an integral optical feature or with a separate optical apparatus.
For example, spatial relationship between the two conduits is one
solution. In FIG. 4, a suction conduit, channel 11, is integral to an instrument
10 that houses a laser-transmitting fiber22 inside its other channel
12. A divider 17 having a distal end 20 partly separates channel
11 from channel 12. The housing 10 has a distal end 16 that
comes into contact with a stone 34 that is to be removed. The laser fiber
22 is connected to a laser source 24 at its proximal end
26. The laser fiber 22's distal tip 28 is close to both the distal
end 16 of the housing 10 and the distal end20 of the divider
17, so that stones caught at either of the distal ends 16 and
20 can be exposed to laser radiation emitted from tip 28.
In the particular embodiment shown in FIG. 4, both the laser fiber's
distal tip 28 and the divider 17's distal end 20 are disposed
within the distal end 16 of the housing 10. In other embodiments,
both or either of the distal tip 28 and the distal end 20 may be flush
with the distal end 16 of the housing or may extend beyond it so long as
at least a portion of the laser radiation from tip 28 can effectively fragment
a stone caught at the distal region of the suction conduit 11.
In FIGS. 5A-5B, the divider 17 is positioned so that it facilitates
the placement of a laser fiber 22 at a beveled angle with the longitudinal
axis of the housing 10, thereby directing laser radiation emitted from tip
28 of the energy-transmitting conduit 22 towards the distal region
of suction conduit 11. Furthermore, because the diameter of the suction conduit
increases towards its proximal end, clogging along the body of the suction conduit
In other embodiments, a portion of the energy emitted from the tip
28 may be directed towards the distal end of the suction conduit through
modifications to the energy-transmitting conduit. For example, the distal end of
a typical, commercially available laser fiber can be modified so that a larger surface
area will be radiated by the laser. FIGS. 6A-6C disclose examples of modifications
with various optical lenses disposed at the laser fiber tips to diffuse the laser
energy. These optical lenses are easily manufactured by removing the plastic jacket
from the distal region of the fiber, then using a torch to thermally heating up
the remaining optical core at the distal end, including its usual silicon clad.
The tip will melt, and after cooling off in room temperature, will form a ball as
shown in Fig. 6A. If the molten tip is pressed against a nonporous, flat surface
at a right angle, a flat-end tip resembling that shown in FIG. 6B will result. Further
pressing the same flat surface on the lateral sides of the tip will result in an
extended tip resembling what is shown in FIG. 6C. An extended tip, of about 5 mm,
is especially advantageous for continued use of the same laser fiber.
Other means of affecting the direction of laser path without resorting
to additional apparatus include etching near the distal end of the energy-transmitting
conduit or bending the distal tip for side-firing (described in U.S. Pat. No. 5,416,878).
Cutting at multiple spots in the distal region of a laser fiber results
in light emission along the distal region, in addition to the distal end. FIG. 7A
provides a specific example of etching, where the distal end 28 of a laser
fiber is cut so that an angled tip is formed. In a schematically depicted laser
fiber 22, laser light 42 travels along the optical core
37 via bouncing between the silicon clad 36, which is further wrapped
in a plastic jacket 35. As shown here, because in the angled tip, one side
of the fiber is longer than the other, some of the laser light 42 will be deflected
side-wise once it reaches the end of the optical core 37.
Reflective coatings on the laser fiber may also be used to affect
the laser path. Referring to FIG. 7B, a portion of the distal region of the laser
fiber 22 has been stripped of the plastic jacket 35 and the silicon clad
36 (therefore "unclad"), and at least one layer of reflective coating 50
has been selectively applied to the remaining unclad optical core, including the
distal face 48. The reflective coating 50 is not applied to certain
areas on the unclad optical core so that reflected laser light can "escape" from
these areas and reach a target such as the distal region of the suction conduit.
Depending on the effectiveness of the coatings, however, some of the light might
still go through the coated areas.
An optic, separate from the energy-transmitting conduit may be placed
near the distal end of the energy-transmitting or of the suction conduit to help
direct the emitted energy towards the distal region of the suction conduit. The
devices of the invention include an optical apparatus.
Several optics known in the art that guide laser emission to a certain
area can be used in the invention. They can be a surface, a series of surfaces,
a medium, a series of media, or a combination of any of the above that alters the
path of light. For example, a light diffusing apparatus is described in U.S. Patent
No. 5,151,096 to Khoury. Examples of other optics include and are not limited to
a lens, a mirror (U.S Pat. No. 4,445,892), a series of mirrors (U.S. Pat. No. 5,496,306),
a prism (U.S. Pat. No. 5,496,309) and a parabolic reflector (U.S. Pat. No. 4,672,961);
In the present invention, the optical apparatus is operatively associated
with the two conduits to help direct laser light from the distal end of the energy-transmitting
conduit toward the distal region of the suction conduit. In FIGS. 8A-8B, an embodiment
has an optical apparatus 30 coupled near the distal end 16 of a housing
similar to that shown in FIG. 4. In the embodiment shown in FIG. 8A, the divider
17 is receded proximal to the optical apparatus 30, which, in turn,
is receded inside the distal end 16 of the housing 10. In the embodiment
shown in FIG. 8B, the divider 17 extends all the way to the distal end
16 of the housing 10, and the optical apparatus 30 is also
positioned more outward. The angle of the optical apparatus 30 may be varied
to direct a larger portion of the energy emitted from the laser fiber
22 inside, across or outside the face of the distal end 16.
The optical apparatus 30 can be made of a variety of materials
that are known in the art to be suitable for reflecting, deflecting, diffusing,
or refracting the particular energy emitted from the tip 28 of the laser
fiber. Such materials include, but are not limited to, crystal, quartz, garnet,
stainless steel or gold. The optical apparatus 30 may assume a variety of
configurations such as a planar surface, an ellipsoidal surface, a convex surface
or a pyramid.
The device with an optical apparatus may utilize Ho:YAG laser energy
which produces a vaporization bubble, a semi-circle of energy, extending from the
tip of a firing laser fiber to a target stone when the laser tip is immersed in
liquid. While the body lumen where the device is operating generally has plenty
of water, a separate irrigation conduit can be added to the device to ensure that
the tip is constantly immersed in water. The optical apparatus 30 in FIGS.
8A and 8b directs the vaporization bubble (not shown) into the distal region of
the suction conduit 11 and onto the stone 34. A shock-wave is then
produced by the collapse of the vaporization bubble at the interface between water
and the stone.
Referring to FIG. 9, another preferred embodiment of the device has
a reflective surface31 (a mirror, for example) fixedly attached to the distal
end of an energy-transmitting conduit (a laser fiber 22 in this case). A
housing 32, preferably made with a light-transmitting hard material such
as quartz, fixedly encloses the distal region of the laser fiber 22. The
housing 32 protects the laser fiber 22 and acts as a lens for the
laser. Laser energy emitted from distal end 18 of fiber22 is reflected by
the reflective surface 31 and travels through the housing 32 to the
distal region of the suction conduit 11. Alternatively, the housing can be
made of an opaque material with an opening for the laser light to travel to the
distal region 5 of the suction conduit 11.
Different embodiments and various features of the invention can be
combined in the same device in accordance with the invention. An embodiment may
contain multiple optical features and any of the distal barriers mentioned earlier.
For example, multiple laser fibers modified with an optical lens-tip as illustrated
in FIGS. 6A-6C, and braided together as shown in FIG. 3C, may be disposed inside
the distal end of the barrier 25 of the device shown in FIG. 2F--the barrier
25 is made of glass, quartz or sapphire and serves as a lens at the same
There are several ways to direct a larger portion of emitted energy
towards the distal region 5 of the suction conduit. In one embodiment, the diameter
of the energy-transmitting conduit is increased. In other embodiments, an optical
apparatus is added. Alternatively, more energy-transmitting conduits can be incorporated
into the device. In a preferred embodiment, these conduits are intertwined and bundled
before being incorporated into the device. Again, all these measures can be implemented
in the same embodiment. In another preferred embodiment shown in FIGS. 10A and 10B,
multiple energy-transmitting conduits such as multiple laser fibers22 are
housed in multiple channels of a housing 10. In this particular embodiment,
these channels surround the suction conduit 1. Some of the channels may enclose
other functional components. As shown in FIGS. 10A and 10B, one of the channels
is an irrigation channel 45, which transfers a cooling agent from an irrigation
source 38. Another channel contains a guidewire 46. Two other channels
each contain a pullwire 47. A pullwire is a wire fixedly attached to the
distal end 16 of an endoscopic instrument and a user can deflect the distal
end 16 upon pulling such a wire.
The devices of the invention may be combined with, or incorporated
into, a catheter, an endoscope or other medical devices customarily used for the
destruction and removal of unwanted materials from body lumens. Preferably, when
incorporated into an endoscope, the devices of the invention combine a guidewire,
a fiber optic for illumination, a fiber optic for visualization, a conduit for irrigation
and pullwires for active deflection.
The devices of the invention have applications in lithotripsy. The
device 10 shown in FIGS. 10A and 10B is placed with its distal end
16 in the vicinity of a calculus. Upon application of vacuum in the suction
conduit 1, the suction pulls large stone fragments toward the distal end
16 of the housing 10. The laser system 24 delivers laser energy
to the tip of the laser fibers 22. The laser energy is then emitted from
the tip of the laser fibers 22. The laser energy may be in the form of a
vaporization bubble. Optionally, an optical apparatus further directs the laser
energy released from the laser fiber 22 into, across the face of, and/or
outside of the suction conduit 1 and onto a stone. The laser energy impacts
the stone caught by the suction at the distal region of the suction conduit
1, causing it to be propelled off the tip and fragmented into smaller stone
fragments. The suction then pulls the smaller fragments back into the distal region
of the conduit 1. Fragments small enough will enter the suction conduit and
be evacuated from the treatment site. Large fragments will be held at the distal
end of the suction conduit. The laser energy impacts the stone fragment causing
it to be propelled off the tip and fragment into even smaller fragments. This process
is repeated until the stone fragments are small enough to be all evacuated through
the suction conduit 1. Directing at least some of the laser energy into the
suction conduit 1 keeps the conduit clear of obstruction.
In addition to removing stones, the devices of the invention can be
utilized to remove soft tissue, for example, to facilitate the treatment of tumors
or soft growths in both the gastrourinary (GU) and the gastrointestinal (GI) tract.
Specifically, the devices can be utilized to shear off and evacuate soft tissue
such as polyps. Papillary lesions can be fragmented and evacuated while the base
of the lesion is coagulated.
In one embodiment for treatment of soft tissue, illustrated in FIG.
11, the laser lithotripsy device is modified to facilitate the removal of polyps.
The tip 28 of the laser fiber 22 and the optical apparatus
30 attached to the distal end 16 are both disposed within the channel
12 about 2 millimeters from the distal end 16. Soft tissue
40 such as a polyp or tumor is sucked into the suction channel
11, is sheared off by the laser energy emitted by the laser fiber
22, and then is evacuated by the suction. The angle of the optical apparatus
30 may be varied to change the direction of the laser energy emitted from
the tip 28. The laser lithotripsy device with an angled laser fiber tip but
without a separate optical apparatus may also be modified to accommodate soft tissue
by moving the tip 28 of the laser fiber 22 further within the channel
12 several millimeters from the distal end 16. Alternatively, the
device can be equipped with fluoroscopic guidance so that the laser can be directed
onto the polyp or tumor.