U.S. patent application number 10/699212 was filed with the patent office on 2004-05-13 for endovenous closure of varicose veins with mid infrared laser.
Invention is credited to Goldman, Mitchell P., Hennings, David R., Johnson, Don, Taylor, Eric B., Weiss, Robert A..
Application Number | 20040092913 10/699212 |
Document ID | / |
Family ID | 32230370 |
Filed Date | 2004-05-13 |
United States Patent
Application |
20040092913 |
Kind Code |
A1 |
Hennings, David R. ; et
al. |
May 13, 2004 |
Endovenous closure of varicose veins with mid infrared laser
Abstract
This invention is an improved method and device for treating
varicose veins 200 or the greater saphenous vein 202. The method
comprises the use of infrared laser radiation in the region of 1.2
to 1.8 um in a manner from inside the vessel 200 or 202 such that
the endothelial cells of the vessel wall 704 are damaged and
collagen fibers in the vessel wall 704 are heated to the point
where they permanently contract, the vessel 200 or 202 is occluded
and ultimately resorbed. The device includes a laser 102 delivered
via a fiber optic catheter 300 that may have frosted or diffusing
fiber tips 308. A motorized pull back device 104 is used, and a
thermal sensor 600 may be used to help control the power required
to maintain the proper treatment temperature.
Inventors: |
Hennings, David R.;
(Roseville, CA) ; Goldman, Mitchell P.; (La Jolla,
CA) ; Weiss, Robert A.; (Hunt Valley, MD) ;
Taylor, Eric B.; (Roseville, CA) ; Johnson, Don;
(Roseville, CA) |
Correspondence
Address: |
Ray K. Shahani, Esq.
ATTORNEY AT LAW
Twin Oaks Office Plaza
477 Ninth Avenue, Suite 112
San Mateo
CA
94402-1854
US
|
Family ID: |
32230370 |
Appl. No.: |
10/699212 |
Filed: |
October 30, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60422566 |
Oct 31, 2002 |
|
|
|
Current U.S.
Class: |
606/3 ; 606/15;
606/9 |
Current CPC
Class: |
A61B 2018/2261 20130101;
A61B 2090/036 20160201; A61B 2018/00196 20130101; A61B 18/24
20130101; A61B 2018/00005 20130101; A61B 2017/00084 20130101 |
Class at
Publication: |
606/003 ;
606/009; 606/015 |
International
Class: |
A61B 018/24 |
Claims
We claim:
1. An endovenous method of treating a varicose vein using a laser
having a wavelength between about 1.2 and about 1.8 um to heat and
shrink collagen in a varicosed vessel wall in the absence of
blood.
2. The method of claim 1 in which the laser energy is delivered
with a fiber optic laser delivery device.
3. The method of claim 1 further comprising the following steps:
Inserting a fiber optic laser delivery device into the varicose
vein; Using a pullback device to retract the fiber optic laser
delivery device through the varicose vein at a rate of between
about 0.1 mm/sec and about 10.0 mm/sec while simultaneously
delivering laser energy therefrom.
4. The method of claim 3 in which the fiber optic laser delivery
device is retracted at a rate of between about 1.0 mm/sec and about
5.0 mm/sec.
5. The method of claim 3 in which the pullback device begins
retraction of the fiber optic laser delivery device just prior to
initiating delivery of the laser energy, thereby preventing the tip
of the fiber, optic laser delivery device from sticking to the
vessel wall.
6. The method of claim 1 in which blood is removed from the
varicosed vein prior to treatment with laser energy.
7. The method of claim 2 in which the fiber optic laser delivery
device is introduced to the varicose vein through an introducer
catheter.
8. The method of claim 2 in which the energy delivered through the
fiber optic laser delivery device is evenly distributed by using a
diffuse radiating-tip mounted to the distal end of the fiber optic
laser delivery device.
9. The method of claim 2 in which an non-contact thermal sensor is
used to maintain a desired temperature.
10. The method of claim 9 in which the thermal sensor is used to
maintain a desired coagulation temperature.
11. The method of claim 9 in which the thermal sensor is used to
maintain a desired collagen shrinkage temperature.
12. The method of claim 9 further comprising the step of using the
fiber optic laser delivery device as a sensing element.
13. The method of claim 9 further comprising the step of modulating
the laser power based on the sensed temperature to maintain the
desired temperature.
14. A system for endovenous treatment of varicose veins comprising
the following: A laser having a wavelength between about 1.2 and
about 1.8 um; A fiber optic laser delivery device having a proximal
end and a distal end, for delivery of laser energy from the distal
end of the fiber optic laser delivery device to the inside wall of
a varicose vein; and A pullback device which retracts the fiber
optic laser delivery device through the varicose vein at a rate of
between about 0.1 mm/sec and about 10.0 nm/sec while simultaneously
delivering laser energy therefrom, wherein collagen in the
varicosed vessel wall can be heated and shrunk in the absence of
blood.
15. The system of claim 14 in which the pullback device retracts
the fiber optic laser delivery device through the varicose vein at
a rate of between about 1.0 mm/sec and about 5.0 mm/sec.
16. The system of claim 14 further comprising anesthesia
administered to tissue surrounding the varicose vein, wherein the
anesthesia causes swelling of the tissue surrounding the varicose
vein which causes compression of the varicose vein in order to
remove blood prior to treatment.
17. The system of claim 14 further comprising an introducer
catheter, wherein the fiber optic laser delivery device can be
introduced to the varicose vein.
18. The system of claim 17 in which the introducer catheter
comprises an elongated lumen portion having a proximal end and a
distal end, wherein the fiber optic laser delivery device is
introduced to the introducer catheter through the proximal end and
is introduced to the varicose vein through the distal end.
19. The system of claim 18 further comprising a diffusing tip at
the distal end of the introducer catheter for providing even
distribution of energy radiating during treatment.
20. The system of claim 18 further comprising a diffusing tip at
the distal end of the fiber optic laser delivery device for
providing even distribution of energy radiating during
treatment.
21. The system of claim 14 further comprising an non-contact
thermal sensor.
22. The system of claim 21 further comprising a controller coupled
to the thermal sensor for controlling the temperature in a region
near the distal end of the fiber optic laser delivery device.
23. The system of claim 22 in which the controller modulates a
power input to the laser for controlling the temperature in a
region near the distal end of the fiber optic laser delivery
device.
24. The system of claim 21 wherein the fiber optic laser delivery
device is also the thermal sensor.
Description
RELATED APPLICATIONS
[0001] This Application is related to U.S. Provisional Patent
Application Serial No. 60/422,566 filed Oct. 31, 2002 entitled
ENDOVENOUS CLOSURE OF VARICOSE VEINS WITH MID INFRARED LASER, which
is incorporated herein by reference in its entirety, and claims any
and all benefits to which it is entitled therefrom.
FIELD OF THE INVENTION
[0002] The present invention relates generally laser assisted
method and apparatus for treatment of varicose veins, and more
particularly, to an improved catheter method and apparatus to
target blood vessel walls directly and with a controlled amount of
the appropriate type of energy using a motorized pull-back
device.
BACKGROUND OF THE INVENTION
[0003] Most prior techniques to treat varicose veins have attempted
to heat the vessel by targeting the hemoglobin in the blood and
then having the heat transfer to the vessel wall. Lasers emitting
wavelengths of 500 to 1100 nm have been used for this purpose from
both inside the vessel and through the skin. Attempts have been
made to optimize the laser energy absorption by utilizing local
absorption peaks of hemoglobin at 810, 940, 980 and 1064 nm. RF
technology has been used to try to heat the vessel wall directly
but this technique requires expensive and complicated catheters to
deliver electrical energy in direct contact with the vessel wall.
Other lasers at 810 nm and 1,06 um have been used in attempts to
penetrate the skin and heat the vessel but they also have the
disadvantage of substantial hemoglobin absorption which limits the
efficiency of heat transfer to the vessel wall, or in the cases
where the vessel is drained of blood prior to treatment of
excessive transmission through the wall and damage to surrounding
tissue. All of these prior techniques result in poor efficiency in
heating the collagen in the wall and destroying the endothelial
cells.
[0004] Baumgardner and Anderson teach the advantages of using the
mid IR region of optical spectrum 1.2 to 1.8 um, to heat and shrink
collagen in the dermis.
[0005] The prior art teaches manual retraction of the catheter.
This is a major cause of overheating and perforation of the vessel
wall as even the best surgeon may have difficulty retracting the
fiber at exactly the correct speed to maintain a vessel wall
heating temperature of 85 deg C. Other prior art using
thermocouples at the tip of the catheter depend on electrical
contact between electrodes inside the vessel and are expensive and
require very slow catheter-withdrawal (2 cm/min.) and are difficult
to use.
[0006] The relevant references in the prior art teach use of much
higher power levels, such as between about 10 to about 20 watts.
This is because the prior art laser wavelengths are not as
efficiently coupled to the vessel wall and are instead absorbed in
the blood or transmitted through the wall into surrounding tissue.
It will be understood that methods taught in the prior art can be
inefficient to such a degree that external cooling is mandatory on
the skin surface to prevent burns.
[0007] Finally, the methods and apparatus taught in the prior art
does not mention the use of defusing catheter tips for varicose
vein treatment. Use of common, standard, non-diffusing tip fiber
optic and other laser delivery devices increases the risk for
perforation of the cannulated vessel.
[0008] Navarro et al., U.S. Pat. No. 6,398,777 issued Jun. 4, 2002,
teaches a device and method of treating varicose veins that
involves using a laser whose wavelength is 500 to 1100 nm and is
poorly absorbed by the vessel wall. Laser energy of wavelengths
from 500 to 1100 nm will penetrate 10 to 100 mm in tissue unless
stopped by an absorbing chromophore. See figure X. Most of the
energy used by this method passes through the vessel wall and
causes damage to surrounding tissue. Procedures using these
wavelengths can require cooling of the surface of the leg to
prevent burning caused by transmitted energy. Operative
complications of this technique include bruising and extensive pain
caused by transmitted energy and damage to surrounding tissue.
[0009] However, this technique does appear to be clinically
effective because the blood that remains in the vein after
compression absorbs the 500 to 1100 nm energy. 500 to 1100 nm light
is absorbed in less than 1 mm in the presence of hemoglobin. See
figure X. This blood heats up and damages the vein wall by
conduction, not by direct wall absorption as claimed by
Navarro.
[0010] This prior art technique is poorly controlled because the
amount of residual blood in the vein can vary dramatically. During
an actual procedure using 500 to 1100 nm lasers it is possible to
see the effects of blood absorption of the energy. At uncontrolled
intervals white flashes will be seen indicating places of higher
blood concentration. The blood can boil and explode in the vessel
causing occasional perforation of the vein wall and unnecessary
damage to healthy tissue.
[0011] In places without residual blood the laser energy has no
absorbing chromophore and will be transmitted through the wall
without causing the necessary damage and shrinkage claimed by the
inventors.
[0012] Navarro claims that the treatment device described must be
in direct "intraluminal contact with a wall of said blood vessel".
This is necessary because the 500 to 1100 nm laser cannot penetrate
any significant amount of blood, even though it requires a thin
layer of blood to absorb and conduct heat to the vessel wall. This
is very difficult to achieve and control.
[0013] Navarro also claims the delivery of energy in bursts. This
is required using their technique because they have no means to
uniformly control the rate of energy delivered. Navarro teaches a
method of incrementally withdrawing the laser delivery fiber optic
line while a laser burst is delivered. In clinical practice this is
very difficult to do and results in excessive perforations and
complications.
[0014] Closure of the greater saphenous vein (GSV) through an
endolumenal approach with radiofrequency (RF) or lasers has been
proven to be safe and effective in multiple studies. These
endovenous occlusion techniques are less invasive alternatives to
saphenofemoral ligation and/or stripping. They are typically
performed under local anesthesia with patients returning to normal
activities within 1-2 days.
[0015] RF energy can be delivered through a specially designed
endovenous electrode with microprocessor control to accomplish
controlled heating of the vessel wall, causing vein shrinkage or
occlusion by contraction of venous wall collagen. Heating is
limited to 85 degrees Celsius avoiding boiling, vaporization and
carbonization of tissues. In addition, heating the endothelial wall
to 85 degrees Celsius results in heating the vein media to
approximately 65 degrees Celsius which has been demonstrated to
contract collagen. Electrode mediated RE vessel wall ablation is a
self-limiting process. As coagulation of tissue occurs, there is a
marked decrease in impedance that limits heat generation.
[0016] Presently available lasers to treat varicose veins
enddolumenialy heat the vessel by targeting the hemoglobin in the
blood with heat transfer to the vessel wall. Lasers emitting
wavelengths of 500 to 1064 nm have been used for this purpose from
both inside the vessel and through the skin. Attempts have been
made to optimize the laser energy absorption by utilizing local
absorption peaks of hemoglobin at 810, 940, 980 and 1064 nm. The
endovenous laser treatment (EVLT.TM.) of the present invention
allows delivery of laser energy directly into the blood vessel
lumen in order to produce endothelial and vein wall damage with
subsequent fibrosis. It is presumed that destruction of the GSV
with laser energy is caused by thermal denaturization. The presumed
target is intravascular red blood cell absorption of laser energy.
However, thermal damage with resorption of the GSV has also been
seen in veins emptied of blood. Therefore, direct thermal effects
on the vein wall probably also occur. The extent of thermal injury
to tissue is strongly dependent on the amount and duration of heat
the tissue is exposed to. When veins are, devoid of blood, vessel
wall rupture occurs.
[0017] One in vitro study model has predicted that thermal gas
production by laser heating of blood in a 6 mm tube results in 6 mm
of thermal damage. This study used a 940-nm-diode laser with
multiple. 1 5Jr.about.second pulses to treat the GSV. Histologic
examination of one excised vein demonstrated thermal damage along
the entire treated vein with evidence of perforations at the point
of laser application described as "explosive-like" photo-disruption
of the vein wall. Since a 940 nm laser beam can only penetrate 0.03
mm in blood (17), the formation of steam bubbles is the probable
mechanism of action.
[0018] Initial reports have shown endovenous RF to have excellent
short-term efficacy in the treatment of the incompetent GSV, with
96% or higher occlusion at 1-3 years with a less than 1% incidence
of transient paresthesia or erythema (10-11) Although most patients
experience some degree of post-operative ecchymosis and discomfort,
no other major or minor complications have been reported.
[0019] Patients treated with EVLT have shown an increase in
post-treatment purpura and tenderness. Most patients do not return
to complete functional normality for 2-a days as opposed to the 1
day "down-time" with RF Closure.TM.b of the GSV. Since the
anesthetic and access techniques for the 2 procedures are
identical, it is believed that non-specific perivascular thermal
damage is the probable cause for this increased tenderness. In
addition, recent studies suggest that pulsed laser treatment with
its increased risk for vein perforation may be responsible for the
increase symptoms with EVLT vs RF treatment. Slow uncontrolled
pull-back of the catheter is likely one cause for overheating and
perforation of the vessel wall as even the best surgeon may have
difficulty retracting the fiber at exactly the correct speed to
maintain a vessel wall heating temperature of 85 deg C. This
technique prevents damage to surrounding tissue and perforation of
the vessel.
ADVANTAGES AND SUMMARY OF THE INVENTION
[0020] This invention is a method and device to treat varicose
veins by targeting the vessel wall directly with a more appropriate
wavelength of laser light and controlling that energy precisely
using a motorized pull back device, diffuse fiber delivery systems
and utilizing thermal feedback of the treated tissue. This
technique allows less energy to be used and helps prevent damage to
surrounding tissue and perforation of the vessel.
[0021] It is an object and an advantage of the present invention to
provide an improved method and device that uses a laser wavelength
that transmits through any residual blood in the vessels and is
absorbed by the water and collagen of the vessel wall. This new
technique is more predicable and controllable in the presence of
residual blood and is more effective in targeting only the vessel
wall.
[0022] Clinical experiments have demons treated that perforation of
the vessel wall does not occur using 1.2 to 1.8 um energy, even if
the fiber remains at one location for several seconds. This is
because the laser energy is uniformly and predictably absorbed
without any hot spots, boiling, or explosions caused by blood
pockets.
[0023] Clinical experiments have demonstrated a much lower
incidence of pain and collateral bruising using 1.2 to 1.8 um laser
energy because the vessel wall always stops the energy. Very little
transmits outside the vessel to cause damage.
[0024] Clinical experiments have demonstrated the coagulation of
side vessels concurrently with larger vessel treatment due to a
wave guiding effect of the 1.2 to 1.8 um laser energy into the
smaller vessels. This has not been observed using 500 to 1100 nm
laser energy because residual blood will absorb and stop any energy
from getting into the branch vessels.
[0025] The present improved device and method in contrast to the
teachings of the prior art does not require direct intraluminal
contact with the vessel wall because it is less affected by
residual blood. The energy passes through the residual blood
without boiling or exploding and is absorbed primarily by the
vessel wall. This is a significant clinical improvement over the
methods of the prior art, with much better control and
predictability.
[0026] The present improved device and method utilize a
continuously running laser and energy delivery with a continuous
controlled withdrawal rate using a motorized pull back device.
[0027] Clinical results have shown this device and method to be
clearly superior. It is easier to do for less experienced surgeons
and helps eliminate perforations, pain and bruising.
[0028] Numerous other advantages and features of the present
invention will become readily apparent from the following detailed
description of the invention and the embodiments thereof, from the
claims and from the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] FIG. 1 is a representative schematic block diagram of a
preferred embodiment of the apparatus 100 of the present invention
for performing a preferred embodiment of the varicose vein closure
procedure of the present invention.
[0030] FIG. 2A is a representative view of varicosed veins 200 to
be treated according to the preferred embodiment of the method and
apparatus of the present invention.
[0031] FIG. 2B is a representative-view of the GSV 202 to be
treated according to the preferred embodiment of the method and
apparatus of the present invention.
[0032] FIG. 3A is a representative view showing the beginning of
the introducer or dilator 300 for percutaneous access according to
the preferred embodiment of the method and apparatus of the present
invention.
[0033] FIG. 3B is a representative view showing the use of the
introducer or dilator 300 with the laser fiber 306 passing through
the lumen 302 of the dilator 300 and into the GSV 202 according to
the preferred embodiment of the method and apparatus of the present
invention.
[0034] FIG. 4 is a representative view of the use of an ultrasound
device 400 according to the preferred embodiment of the method and
apparatus of the present invention.
[0035] FIG. 5 is a representative view of a physician 500
performing manual compression of tissue near the tip 308 of the
fiber 306 according to the preferred embodiment of the method and
apparatus of the present invention.
[0036] FIG. 6 is a representative view of the non-contact thermal
sensor 600 and the cooling system 602 of the preferred embodiment
of the method and apparatus of the present invention.
[0037] FIG. 7 is a is a representative view of a varicosed vein
200, showing prolapsed valves 690.
[0038] FIG. 8 is a representative view of administration of
tumescent anesthesia 700 and how it compresses the vein 200 around
the fiber 306 according to the preferred embodiment of the method
and apparatus of the present invention.
[0039] FIG. 9A is a representative view of a diffusing fiber tip
according to the preferred embodiment of the method and apparatus
of the present invention.
[0040] FIG. 9B is a representative view of another diffusing fiber
tip according to the preferred embodiment of the method and
apparatus of the present invention.
[0041] FIG. 9C is a representative view of yet another diffusing
fiber tip according to the preferred embodiment of the method and
apparatus of the present invention.
[0042] FIG. 10 shows curves for absorption coefficients of melanin,
hemoglobin and water as a function of wavelength according to the
preferred embodiment of the method and apparatus of the present
invention.
[0043] FIG. 11 is a photograph of experimental results showing the
distal greater saphenous vein immediately after treatment with a
1320 nm Nd:YAG laser.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0044] The description that follows is presented to enable one
skilled in the art to make and use the present invention, and is
provided in the context of a particular application and its
requirements. Various modifications to the disclosed embodiments
will be apparent to those skilled in the art, and the general
principals discussed below may be applied to other embodiments and
applications without departing from the scope and spirit of the
invention. Therefore, the invention is not intended to be limited
to the embodiments disclosed, but the invention is to be given the
largest possible scope which is consistent with the principals and
features described herein.
[0045] It will be understood that in the event parts of different
embodiments have similar functions or uses, they may have been
given similar or identical reference numerals and descriptions. It
will be, understood that such duplication of reference numerals is
intended solely for efficiency and ease of understanding the
present invention, and are not to be construed as limiting in any
way, or as implying that the various embodiments themselves are
identical.
[0046] FIG. 1 is a representative schematic block diagram of a
preferred embodiment of the apparatus 100 of the present invention
for performing a preferred embodiment of the varicose vein closure
procedure of the present invention. As shown, the system 100 of the
present invention includes a laser console 102, a motorized, fiber
optic catheter "pull-back" machine 104, a fiber optic catheter or
other laser delivery device 106 to deliver laser energy into the
patient's vein, a sterile field 108 and a controller 110.
[0047] FIG. 2A is a representative view of varicosed veins 200 to
be treated according to the preferred embodiment of the method and
apparatus of the present invention. FIG. 2B is a representative
view of the GSV 202 to be treated according to the preferred
embodiment of the method and apparatus of the present invention.
FIG. 3A is a representative view showing the beginning of the
introducer or dilator 300 for percutaneous access according to the
preferred embodiment of the method and apparatus of the present
invention. FIG. 3B is a representative view showing the use of the
introducer or dilator 300 with the laser fiber 306 passing through
the lumen 302 of the dilator 300 and into the GSV 202 according to
the preferred embodiment of the method and apparatus of the present
invention.
[0048] FIG. 4 is a representative view of the use of an ultrasound
device 400 according to the preferred embodiment of the method and
apparatus of the present invention. FIG. 5 is a representative view
of a physician 500 performing manual compression of tissue near the
tip 308 of the fiber 306 according to the preferred embodiment of
the method and apparatus of the present invention. As described
herein, it will be understood that the means for applying
mechanical compression of the tissue near the tip 308 of the fiber
includes manual compression, mechanical clamps or straps, chemical
or other drug-induced swelling, etc.
[0049] FIG. 7 is a is a representative view of a varicosed vein
200, showing prolapsed valves 690. FIG. 8 is a representative view
of administration of tumescent anesthesia 700 and how it compresses
the vein 200 around the fiber 306 according to the preferred
embodiment of the method and apparatus of the present
invention.
[0050] Prior to treatment with the laser 102, blood is removed from
the vessel 200 by using tumescent anesthesia 700, typically
consisting of lidocaine 0.05 to 0.1% in normal saline. Alternate
compositions for tumescent anesthesia 700 will be known to those
skilled in the art. A quartz or sapphire fiber optic 306 is
inserted into the vein 200 via a 16 gauge needle or similar, or
through the vein 200 which has been externalized through a 2-3 mm
incision with a phlebectomy hook (not shown). The fiber 306 is
preferably 500 to 600 um in diameter, but fibers from 50 um to 1 mm
or more or less, could be used. The fiber catheter 300 is threaded
through the length of the vein 200. The position of the fiber 306
within the vein 200 is noted by observing the red aiming beam of
the laser 102 as it is emitted from the tip 304 of the catheter 300
and is visible through the skin. In addition, a duplex ultrasound
device 400 or similar may be used to visualize the fiber tip 308 as
well as the cannulated blood vessel 200 to determine vein wall
contraction and closure. In a preferred embodiment of the method of
the present invention, the catheter 300 must either be removed
prior to pull-back, or be secured to the fiber 306 so that both the
fiber 306 and the cannula or catheter 300 are retracted
simultaneously.
[0051] The catheter 300 is connected to a motorized pullback device
104 either inside or outside of the sterile field 108 of the
patient. The procedure begins by starting the pull back for about 2
or 3 mm and then turning the laser 102 on at about 5 watts of
power. The procedure could also be done at 1 to 20 watts of power
by varying the speed of the pullback device 104.
[0052] Optical absorption curves presented by Baumgardner,
Anderson, and Grove show that the primary absorbing chromophore in
a vein for the 810, 940 and 1.06 um laser wavelengths is
hemoglobin. When a vein is drained of blood and these lasers 102
are used, a great majority of the laser energy is transmitted
through the vessel wall and heats surrounding tissue 702. The 1.2
to 1.8 um laser wavelengths are ideally suited to penetrate the
small amount of remaining blood in the vessel 200 but also is much
more strongly absorbed in the vessel wall 704 by collagen. Most of
the energy is concentrated in the wall 704 for heating and
shrinkage and is not transmitted through to surrounding tissue 702.
This dramatically increases, the safety of the procedure. In
addition these laser wavelength are considered more "eye" safe than
the 800 to 1.06 um lasers, decreasing the risk of eye damage to the
doctor and others in the operating arena.
[0053] In particular the Nd:YAG laser 102 or any other suitable,
similar laser can be used. This laser 102 can operate at a
wavelength of 1.32 um and can be either pulsed or continuous wave.
This procedure works best when the laser 102 is continuous or
pulsed at a high repetition rate to simulate a continuous output.
The repetition rate for a pulsed laser 102 should be 10 Hz to
10,000 Hz.
[0054] Other lasers 102 such as Nd:YAP, ER:YAP, ER:YLF and others
could be used to provide laser wavelengths in the 1.2 to 1.8 um
region. These lasers 102 can be powered by optically pumping the
laser crystal using a xenon or krypton flashlamp or laser diodes.
They may be continuously pumped or pulsed using electro optical or
acousto-optical shutters-or by pulsing the, flashlamp itself.
Lasers 102 in this wavelength region also include diode lasers that
emit 1.2 to 1.8 um wavelengths directly, or fiber lasers that use a
length of doped fiber optic as the lasing medium.
COOLING SYSTEM WITH THERMAL FEEDBACK
[0055] The use of a thermocouple or infrared thermal detector 600
has been described for other applications, including on laser
delivery fibers and for the treatment of varicose veins 202 using
an radiofrequency heating device. However, by installing a
thermocouple on the end of the laser delivery fiber optic device
for the treatment of varicose veins, delivery of thermal energy can
be more precisely controlled. In addition, in using fiber optic
devices made of sapphire, a non-contact thermal sensor can be
located in the laser console and measure tip temperature by
measuring the black body infrared radiation profile emitted at the
opposite end of the fiber reflected from the treatment site,
typically via a beamsplitter in the laser console. A small-diameter
sapphire fiber can be constructed that can be sterilized and
re-used. Data obtained from the non-contact thermal sensor
equipment 600 can also be used to either servo control delivery of
the laser energy to maintain a certain temperature at the treatment
site, or the control system can be used as a safety device, i.e.,
to terminate delivery of laser energy if a certain temperature is
exceeded.
[0056] Another type of thermal feedback device 600 can be an
external device that measures the heat that is transmitted out of
the side of the vein 200 or 202 and heats up the surface of the
skin 608 adjacent the treated vein 200 or 202. As described above,
this detector can be either a contact thermocouple or a, non
contact infrared detector 600. A particularly advantageous use of
this type of thermal detection would be to automatically activate a
cooling device 602, such as a cryogen spray, onto the skin surface
604 to keep it cool, or to send an alarm signal to the operator of
the laser that too much energy is being delivered to and escaping
from the treatment site. In an optional configuration, the laser
operator could point an external detector at a red aiming light
that is visible through the skin from the end of the treatment,
fiber, similar to the use of the ultrasound device currently used,
in order to control the location and duration of the delivery of
the laser energy.
[0057] FIG. 6 is a representative view of the non-contact thermal
sensor 600 and the cooling system 602 of the preferred embodiment
of the method and apparatus of the present invention. Non-contact
thermal sensors 600 as well as contact devices, including RTDs, are
well known in the art. It will be understood that the cooling
device 602 can be any suitable, controlled device which allows a
predetermined amount of cryogenic fluid to be dispensed from an
on-board fluid reservoir or from an external/line source. In a
preferred embodiment, the device 602 is computer controlled, to
provide spurts or squirts of cryogenic fluid at a predetermined
rate or for a predetermined duration. The cryogenic fluid is
dispensed onto the surface of the skin 604 in an area adjacent the
fluid dispensing nozzle 606, and the non-contact thermal sensor 600
determines the temperature of the skin in the same area 604 or in
an area 608 distal from the area being cooled 604. The present
invention, this application and any issued patent based hereon
incorporates by reference the following issued patents with regards
surface cooling methods and apparatus utilized in the present
invention: U.S. patent application Ser. No. 08/692,929 filed Jul.
30, 1996, now U.S. Pat. No. 5,820,626. U.S. patent application Ser.
No. 938923 filed Sep. 26, 1997, now U.S. Pat. No. 5,976,123. U.S.
patent application Ser. No. 10/185,490 filed Nov. 3, 1998, now U.S.
Pat. No. 6,413,253. U.S. patent application Ser. No. 09/364275
filed Jul. 29, 1999, now U.S. Pat. No. 6,451,007.
[0058] Diffusing Tip Fibers
[0059] Diffusing tip fibers are well known for use with high energy
lasers in other fields particularly to coagulate cancerous tumors.
In addition they have been used to direct low intensity visible
radiation in conjunction with photo dynamic cancer therapy. As
described in the prior art, diffusing tip fibers typically require
a scattering material like ceramic to be attached to the tip of a
fiber in order to overcome index matching properties of the blood
and liquid that the fiber is immersed into. It is frequently
insufficient to abrade, roughen or shape the end of a quartz fiber
by itself because the index of refraction of typical types of
quartz is very close to the index of the immersing liquid,
therefore any shape or structure formed in the glass or quartz
portion would be ineffective in the liquid. Furthermore, in a
preferred embodiment, there must be an air gap in the tip
somewhere. In an alternate construction, material is selected that
has bulk light scattering characteristics, like most ceramics,
i.e., light is scattered as it passes through the material, as
opposed to simply providing surface scattering properties. The use
of diffusing tip fibers for the treatment of varicose veins is
unique and has not been previously described.
[0060] Use of diffusing tip fibers for treatment of varicose veins
are an improvement because the laser radiation can be directed
laterally from the end of the fiber allowing more precise heating
and destruction of the vein endothelial cells. Non-diffusing fiber
tips direct energy along the axis of the vein and often require
that the vein be compressed, in a downward position as well as
around the fiber, to be most effective. The procedure described
herein will work with either diffusing or non diffusing tip fibers,
however, diffuse radiation will provide a more uniform and
predictable shrinkage of the vein.
[0061] Adding a ceramic or quartz cap to the end of a small fiber
will also aid in inserting the fiber in the vein. The cap can be
made smooth and rounded so that the fiber tip does not catch on the
vein or on valves within the vein as it is being inserted. A cap or
smooth tip also reduces the chance of perforating the vein with a
sharp fiber tip.
[0062] FIG. 9A is a representative view of a diffusing fiber tip
308A according to the preferred embodiment of the method and
apparatus of the present invention. A ceramic or other suitable
material diffusing tip 902 has an internal screw thread 904 which
screws onto a buffer portion 906 of the fiber optic laser delivery
device 306. The threaded portion 904 can be replaced with a clip
portion or any, other suitable mechanical connection. Optionally, a
non-toxic, heat-resistant-or other suitable epoxy 908 is used to
permanently or removably mount the diffusing tip 902 to the fiber
optic laser delivery device 306.
[0063] The epoxy 908 can also be an adhesive, a bonding agent or
joining compound, etc. FIG. 9B is a representative view of another
diffusing fiber tip 308B according to the preferred embodiment of
the method and apparatus of the present invention. As shown, a
small, circular diffusing bead or head 920 formed of ceramic or
other suitable, appropriate material is coupled to the fiber optic
laser delivery device 306. Optionally, a non-toxic, heat-resistant
or other suitable epoxy 908 is used to permanently or removably
mount the diffusing tip 920 to the fiber optic laser delivery
device 306.
[0064] FIG. 9C is a representative view of yet another diffusing
fiber tip 308C according to the preferred embodiment of the method
and apparatus of the present invention. In this embodiment, a
quartz tube 922 is placed over the distal end 906 of the optical
fiber laser delivery device 306, thereby forming a sealed air
chamber 924. Optionally, a spherical or other shaped diffusing ball
926 is placed within the air chamber 924 such that electromagnetic
radiation directed through the fiber optic laser delivery device
306 is diffused as it is delivered from the tip 922 of the device
308C. Optionally, a non-toxic, heat. resistant or other suitable
epoxy 908 or other suitable attachment means is used to permanently
or removably mount the quartz capillary tube 922 to the fiber optic
laser delivery device 306.
[0065] FIG. 10 shows curves for absorption coefficients of melanin,
hemoglobin and water as a function of wavelength according to the
preferred embodiment of the method and apparatus of the present
invention. It will be observed in FIG. 10 that the region between
about 550 nm to about 1060 nm shows high hemoglobin absorption and
low water absorption, as is well known in the prior art technology.
It will further be observed that the region between about 1200 nm
to about 1800 nm shows low hemoglobin and higher water absorption,
which is a key to the present invention. EXPERIMENTAL RESULTS A
novel endoluminal laser was evaluated in 12 incompetent greater
saphenous veins in 11 patients.
[0066] Method Overview: Twelve incompetent greater saphenous veins
in 11 patients were treated with a 1 320 nm "continuous" Nd:YAG
laser at 5W with an automated pull-back system at 1 mm/sec.
Patients were examined at 1 week, 3,6 and 9 months
post-operatively. Ten treated veins were examined
histologically.
[0067] Brief Results: Full thickness vein wall thermal damage
occurred in all patients without evidence for vessel perforation.
No post-operative complications or pain was noted in any patient.
All patients had complete disappearance of the incompetent GSV with
resolution of all pre-operative symptoms.
[0068] Brief Conclusion: The 1320 nm Nd:YAG laser is safe and
effective for endovascular ablation of the incompetent greater
saphenous vein.
[0069] Method: Patient characteristics are found in Table 1.
1TABLE 1 Patient Characteristics: 11 patients 12 Great Saphenous
Veins 10 female 1 male Average Age: 50 (19-78) 12/12 legs had
varicose and reticular veins 12/12 legs had reflux >1. sec
through the saphenofemoral junction down the great saphenous vein
12/12 had leg pain 2/12 had leg edema Great Saphenous vein diameter
2 cm distal to saphenofemoral junction while patient is standing:
5.5-12 mm (Ave. 8.4 mm).
[0070] A 550 um quartz fiber is inserted into the vein through an
externalization approach as previously described and threaded up to
the saphenofemoral junction. The position of the fiber within the
vein is noted by observing the red aiming beam of the laser as it
is emitted from the tip of the catheter as well as through Duplex
evaluation. The catheter is connected to a motorized pull back
device. The procedure begins by starting the pull back for about 2
or 3 mm and then turning the laser on in a near continuous mode at
5W at 167 mjoules given at a repetition rate of 30 Hz. All laser
fibers were withdrawn with a motorized pull-back system at a rate
of 1 mm/second.
[0071] The average length of treated GSV was-1.7.45+/-3 cm. Average
fluence utilized was 755 Joules over 160+/-20 seconds for an
average of 4.7 JIsec. Immediately after the veins were lasered, the
distal 3 cm was excised, the proximal portion ligated with 3/0
vicryl suture and placed in formaldehyde for histopathologic
processing and evaluation. Nine veins were evaluated by a
dermatopathologist blinded to the purpose and parameters of the
experiment.
[0072] Patients were seen back at 1 day, 1 week, 1, 3, 6, and 9,
months post-operatively for Duplex examination. This examination
was performed by a physician not involved in the surgical
procedure.
[0073] Experimental Results:
[0074] All patients tolerated the procedure well without any
noticeable pain or discomfort. All patients had an unremarkable
post-operative course without any pain. Bruising over the course of
the treated vein occurred in 2 of the 12 treated legs and resolved
within 10-14 days. No evidence of superficial thrombophlebitis
occurred.
[0075] Three patients with four treated legs were followed for 9
months, three patients were followed for 6 months and 5 patients
were followed for 3 months.
[0076] All patients remarked on the complete resolution of
preoperative pain. Of the two patients with pedal edema, one
patient had total resolution of the pedal edema. The other
patient-had a 75% reduction in pedal edema.
[0077] Duplex examination of the treated GSV segment demonstrated a
non-compressible totally occluded vessel for 3r5
months-post-operatively in every patient. At 3 months, the
thrombotic GSV was 1-4 mm in diameter smaller (approximately 50%).
At 6 months, the GSV could not be identified in any patient.
[0078] FIG. 11 is a photograph of experimental results showing the
distal greater saphenous vein immediately after treatment with a
1320 nm Nd:YAG laser. Table 2 describes the extent of thermal
damage into the vein wall in mm of amorphous amphophilic material.
In addition, the layers of vein wall exhibiting thermal damage were
described. Full thickness vein wall damage occurred in all
specimens.
2TABLE 2 Perioperative Diameter of the Great Saphenous Vein and
Extent of Thermal Damage from intravascular 1320 nm Laser
Pre-operative Thickness of thermal damage (amorphous amphophilic
Diameter material)(mm) 8.0 mm 0.8 mm full thickness vein wall
damage 9.0 mm Full thickness damage 1 mm in depth including hyper-
chromasia or loss of endothelial nuclei, and subendothelial
necrosis 8.0 mm Full thickness damage of the vein wall to 0.33 mm
of endothelial nuclei and subendothelial necrosis 5.5 mm Full
thickness subendothelial damage to 0.9 mm with hyperchromasia of
endothelial cells 8.2 mm 0.75 mm full thickness vein wall 8.3 mm
0.74 mm full thickness vein wall damage 10 mm 0.6 mm full thickness
vein wall damage 7.7 mm 0.7 mm full thickness vein wall damage 8 mm
0.8 mm full thickness vein wall damage
[0079] Discussion: Optical absorption curves show that the primary
absorbing, chromophore in a vein for the 810, 940 and 1064 nm laser
wavelengths is hemoglobin. When a vein is drained of blood and
these lasers are used a majority of the laser energy is transmitted
through the vessel wall to heat surrounding tissue. The 1 320 nm
laser wavelength is ideally suited to penetrate the small amount of
remaining blood in the vessel and is much more strongly absorbed in
the vessel wall by collagen. Most of the energy is concentrated in
the wall for heating and shrinkage. This study demonstrates that
the 1320 nm-Nd:YAG laser with an automated pull-back system is safe
and effective for endovascular laser destruction of the GSV.
[0080] Unless defined otherwise, all technical and scientific terms
used herein have the same meaning as commonly understood by one of
ordinary skill in the art to which the present invention belongs.
Although any methods and materials similar or equivalent to those
described can be used in the practice or testing of the present
invention, the preferred methods and materials are now described.
All publications and patent documents referenced in the present
invention are incorporated herein by reference.
[0081] While the principles of the invention have been made clear
in illustrative embodiments, there will be immediately obvious to
those skilled in the art many modifications of structure,
arrangement, proportions, the elements, materials, and components
used in the practice of the invention, and otherwise, which are
particularly adapted to specific environments and operative
requirements without departing from those principles. The appended
claims are intended to cover and embrace any and all such
modifications, with the limits only of the true purview, spirit and
scope of the invention.
* * * * *